Neste artigo, discutiremos um esquema de distância quadrilateral adaptativo que pode detectar resistência de falta maior do que na implementação anterior. Além disso, o artigo discute as considerações da aplicação dos elementos de distância quadrilaterais.
Este artigo fornece uma análise da interrupção de energia induzida por ataque cibernético na Ucrânia de 23 de dezembro de 2015 e apresenta uma discussão sobre os métodos de mitigação e recomendações que teriam protegido o sistema de controle da Ucrânia.
Este artigo discute os elementos-chave da criação de um sistema confiável de proteção de motor, incluindo a modelagem térmica, a detecção de barras rompidas no rotor e a detecção de arco voltaico.
artigo apresenta a filosofia dos relés de proteção adotada para proteger os
filtros de harmônicos em uma instalação de 600 kV bipolares, associada com
uma linha de transmissão em corrente contínua de 2400 km no Brasil.
Este artigo descreve a operação de um sistema de controle de uma usina de geração FV frente aos desafios associados à interligação destas instalações ao sistema de potência.
Este artigo discute o uso de redes definidas por software (SDN: “Software-Defined Network”), uma nova arquitetura na tecnologia de redes, visando preencher a lacuna entre a interoperabilidade e os requisitos de transporte das comunicações de alta confiabilidade para o sistema de potência.
Este artigo fornece recomendações para testes dos relés da SEL e diretrizes para o desenvolvimento de um programa de testes em conformidade com a norma NERC PRC-005-2.
Este artigo fornece uma visão geral das tecnologias e sistemas baseados em tempo normalmente utilizados para fornecer tempo preciso, discute as vulnerabilidades do sistema de tempo baseado em GPS e explica como projetar sistemas de distribuição de tempo resilientes para aplicações do sistema de potência visando atenuar estas vulnerabilidades.
Os relatórios de evento continuam a ser um recurso inestimável dos relés baseados em microprocessador. A análise de alguns eventos é relativamente simples e direta, mas outros exigem experiência e conhecimento considerável do sistema de potência e do sistema de relés de proteção para encontrar a causa raiz. Esta sessão fornece diversos exemplos de eventos avançados do mundo real, tempo para avaliação dos mesmos, e soluções.
Este artigo fornece um tutorial sobre a localização de faltas baseada em onda viajante ("traveling wave" – TW) e descreve um algoritmo de localização de faltas baseado em TW que usa medições com sincronização de tempo das correntes das TWs nos terminais da linha para determinar a localização da falta.
Este artigo discute vários aspectos essenciais do projeto elétrico, projeto da rede de comunicação, proteção e controle, além dos testes e comissionamento de uma subestação baseada no IEC 61850.
artigo descreve os benefícios da aplicação da tecnologia multifuncional nos
sistemas de automação de controle dos canais de água. De forma similar a uma
aplicação de distribuição de energia, protocolos de comunicação, lógicas
padronizadas e dispositivos robustos são usados para monitorar e controlar o
fluxo de água, gerenciando ao mesmo tempo a energia necessária para o processo.
Este artigo explora um método de controle de tensão com o objetivo de conservação de energia. A abordagem tradicional da redução da tensão de conservação nem sempre é a abordagem adequada para todos os tipos de cargas de alimentadores; algumas cargas operam de forma mais eficiente em uma tensão mais alta.
Primeiro, este artigo apresenta os desafios do sistema de potência existente e os requisitos para o ECS. Em seguida, são descritos o projeto da solução do ECS e a rede de comunicação.
Este artigo discute os aspectos de implementação e aplicação da localização de faltas através de ondas viajantes em um relé de proteção. Limitações de desempenho são discutidas, bem como os requisitos do sistema e considerações da instalação prática.
objetivo deste artigo não é rever os princípios de proteção dos geradores, pois
isso já foi amplamente efetuado em outros trabalhos, mas sim relembrar os
princípios básicos de física e engenharia que estão por trás da interação entre
o AVR de um gerador síncrono e seus limitadores associados, além de algumas
funções de proteção de geradores.
Os relatórios de evento têm sido um recurso inestimável dos relés microprocessados desde a introdução inicial da tecnologia. Os dias de causa raiz desconhecida para interrupções de operação prolongadas ou resultados de testes inexplicáveis estão amplamente superados devido à esta ferramenta e à capacidade de utilização da mesma por engenheiros e técnicos. É necessário praticar para se tornar proficiente na análise de relatórios de evento. Esta sessão fornece exemplos de eventos do mundo real, tempo para avaliação dos mesmos, e soluções.
Este artigo analisa os efeitos da saturação em vários desses elementos e fornece diretrizes de aplicação que eliminam ou minimizam o risco de saturação do TC.
Este artigo discute o sistema SCADA existente e o sistema de monitoramento de uma área ampla (“wide-area monitoring system” – WAMS) recentemente instalado no Centro de Despacho de Carga da Região Norte (“Northern Regional Load Despatch Centre” – NRLDC) da “Power Grid Corporation of India Limited” (PGCIL).
Considerando a competitividade do mercado de energia elétrica, a prevenção de faltas e defeitos nos equipamentos primários das subestações é considerada um fator diferencial significativo para a qualidade da energia elétrica fornecida pelas concessionárias. A redução do número de faltas e defeitos que causam interrupções no suprimento de energia elétrica contribui enormemente para a melhoria dos índices de desempenho dos serviços prestados. Para atingir este objetivo, é necessária a adoção de práticas de manutenção mais eficientes e inteligentes, além da aplicação adequada dos recursos materiais, humanos e financeiros.
Neste artigo, apresentamos um exemplo de um esquema de rejeição de geração nos sistemas de transmissão de 400 kV, onde a CFE está avaliando o uso da diferença angular através das medições fasoriais sincronizadas para melhorar a confiabilidade dos esquemas de rejeição de geração existentes.
Este artigo discute os conceitos fundamentais dos sistemas de rádio, considerando-os em termos dos requisitos de controle e proteção para os modernos sistemas de potência.
Este artigo aborda outro método para aumentar a confiabilidade dos computadores de subestações - projetá-los para usar memória com código de correção de erros (ECC: “Error-Correcting Code”). O uso da memória ECC minimiza a classe de erros de memória específicos de inversão de bits (“single bit flips”). Quase todos os computadores de classe de servidor usam memória ECC, mas muito poucos computadores de subestação usam memória ECC.
Este artigo apresenta um teste efetuado
recentemente pela área de distribuição de uma concessionária de energia
elétrica para substituição das Unidades Terminais Remotas (UTRs) das chaves de
seccionamento do tipo "padmounted" por controladores de automação programáveis expansíveis, baseados no
protocolo IEC 61850.
artigo descreve a solução adotada pela Comisión Federal de Electricidad (CFE),
que instalou com sucesso um sistema de indicação de faltas com comunicação sem
fio a um leitor remoto portátil em seu sistema de distribuição subterrâneo.
Este artigo descreve o projeto de modernização e energização da SE Guarujá 2, uma subestação integrada através da suite de protocolos IEC 61850.
Devido aos casos já registrados de disjuntores fechando com retardos, uma segura e confiável solução custo-benefício foi desenvolvida para evitar problemas futuros.
Este artigo analisa o conceito e aplicação de crosspoint switches de alta velocidade para implementação do esquema de rejeição de cargas numa instalação industrial.
Universidade de Stanford empenhou-se na execução do projeto de modernização dos
sistemas de proteção e controle de sua Subestação Palou.
relés de proteção multifunção possuem recursos abrangentes de monitoração que
podem detectar os estados de alerta e de emergência, minimizar os distúrbios no
sistema e evitar o colapso do mesmo.
Este artigo analisa várias técnicas usadas para detectar faltas provenientes de fontes delta. O artigo faz uma revisão da natureza das contribuições da corrente de falta e das características a tensão das fontes delta não aterradas, usando a análise das componentes de seqüência. O artigo também discute o possível impacto dos sistemas de controle do gerador distribuído e a proteção da interconexão.
Os transformadores de corrente utilizados nas linhas de transmissão são especificados para evitar saturação durante a porção assimétrica da máxima corrente de falta. A saturação é evitada através da seleção da tensão nominal ANSI maior do que a tensão na carga para o valor máximo de falta, com o fator (1 + X/R) aplicado. Isto é possível nas aplicações de proteção de linhas, uma vez que as elevadas correntes de carga resultam no uso de TCs com alta relação e as correntes de falta são normalmente limitadas de três a cinco, e raramente ultrapassam dez, vezes a corrente primária nominal do TC.
Este artigo avalia a confiabilidade das topologias Ethernet de conexão de subestações para a conexão de dispositivos.
Este artigo descreve duas soluções simples com relés, as quais dão a segurança necessária ao “sympathetic trip”, e mantêm a sensibilidade de detecção de faltas desejada. Também apresenta exemplos do sistema, que ilustram como inserir as impedâncias das cargas nos diagramas de componentes simétricas.
Este artigo foi desenvolvido como um estudo de caso do projeto e instalação de uma casa de controle de uma subestação.
Este artigo fornece uma introdução à utilização de rede Ethernet nas subestações de energia elétrica. Além dos termos e conceitos básicos das redes Ethernet, ele trata de assuntos específicos relativos às redes Ethernet em subestações.
Neste artigo, identificamos as ameaças a controladores de subestações e sistemas SCADA e discutimos mecanismos de mitigação para reduzir a vulnerabilidade às invasões eletrônicas maliciosas.
Este artigo discute o processo de fechamento e interrupção dos contatos metálicos.
O artigo discute a modelagem dos cabos através de componentes simétricas e analisa a performance do elemento direcional de seqüência-negativa durante condições de faltas nos cabos.
Este artigo revisa as tecnologias existentes sobre bancos de capacitores, discute as vantagens e desvantagens das diferentes tecnologias de capacitores e detalha as razões do por quê a Pacific Gas and Electric Co. (PG&E) está implementando a tecnologia de capacitores sem fusíveis em todos os novos projetos nos sistemas de 115 e 230 kV.
Este artigo discute uma nova abordagem para encontrar controle, monitoramento e proteção de linha de alta velocidade, utilizando comunicação lógica digital relé-a-relé microprocessado.
Nós quantificamos a probabilidade de operações errôneas (sobredisparo, desligamento retardado), cobertura da resistência da falta, tempos de operação e complexidade dos diversos esquemas de proteção populares. Propomos um novo esquema, que proporciona operação mais rápida, melhor cobertura da resistência da falta e minimiza os riscos das operações irregulares.
O Relé SEL-321 contém um elemento direcional inovador que usa as grandezas de seqüência-negativa tradicionais de um modo um pouco diferente do que é usado pelos elementos direcionais de seqüência-negativa tradicionais. Este artigo descreve e fornece um método para testar esse novo elemento direcional.
Este artigo apresenta a resposta dos relés microprocessados para formas de onda tais como a distorção do terceiro harmônico na corrente do neutro de distribuição, formas de onda de corrente de retificador de seis pulsos com ressonância, corrente de energização magnetizante do transformador e falsa corrente diferencial em TC’s de barramento em anel, causada por remanência desigual.
Os relés microprocessados na distribuição proporcionam melhorias técnicas e economias no custo sob vários aspectos.
O artigo conclui mostrando várias aplicações de proteção de linhas de transmissão para os relés microprocessados.
Este artigo é um tutorial sobre a análise de circuitos trifásicos de um circuito de linha de transmissão e é de um padrão que pode facilmente ser implementado num computador, usando um programa matemático como Mathcad.
Este artigo mais adiante define a eficiência do autoteste em relés digitais.
Este artigo examina o critério baseado em Z = V/I e expõe as degradações devidas ao fluxo de potência e à resistência de falta.
A maioria dos relés digitais de distribuição proporciona a proteção tradicional para sobrecorrente de fase e terra, funções de religamento e informação limitada sobre medição e eventos. Neste artigo, as características adicionais de relés digitais de istribuição mais avançados serão discutidas.
This document explains the functionality of the SEL Underground AutoRANGER Fault Indicator (AR-URD). It defines the AR-URD AutoRANGER trip logic, principles of operation, fault indication options, inrush restraint, and testing and reset functions.
This paper examines the application of GOOSE over Ethernet radios and the associated challenges. The paper shares results from a real-world implementation, including results from GOOSE latency tests for protection and control applications.
This paper presents practical solutions for testing traveling wave-based (TW-based) relays and fault locators, including a TW relay test set and relay event playback functionality. Both approaches are capable of performing end-to-end testing when an absolute time reference is used.
This paper describes the implementation of a circulating current scheme that uses IEC 61850 GOOSE messages to provide automatic voltage regulation for up to four paralleled power transformers.
This paper discusses the differences between implementing cybersecurity measures in information technology (IT) and operational technology (OT) networks. It introduces software-defined networking (SDN) technology and describes how SDN can be used to build a robust and secure OT network.
This paper describes common failure modes for substation clocks and their recovery mechanisms. It also describes test setups with pass/fail criteria to characterize substation-hardened clocks under conditions of electrical and environmental stress.
This paper presents practical solutions for commissioning testing, including end-to-end testing, of ultra-high-speed relays that use traveling waves and incremental quantities. The paper reviews the relay operating principles and derives adequate testing requirements. It then introduces, explains, and illustrates a testing method that relies on superposition of traveling waves and low-bandwidth signals. The method uses a separate test set to generate sharp current and voltage pulses to represent traveling waves and superimposes them on the low-bandwidth signals provided by a traditional relay test set. The method uses test software to control and synchronize both test sets.
This paper discusses how the SEL-735 Power Quality and Revenue Meter exceeds the nonsinusoidal test requirements for ANSI 0.1 accuracy class compliance. It also illustrates why the SEL-735 is highly qualified for revenue metering applications in today’s challenging power system conditions.
This paper describes new developments in power flow regulating tap-changer control systems for phase-shifting transformers (PSTs), which are also called phase angle regulating (PAR) transformers. This paper discusses recent advancements in the control technology and highlights a particularly challenging application of two parallel PSTs installed on San Diego Gas & Electric's 230 kV transmission system.
This paper presents a tested generation control system that was designed and implemented to adapt to a generation system with multiple inertias, islands, control modes, and voltage levels that will tolerate system contingencies.
This paper describes the design of, and the lessons learned from, a deployment of 300 smart motor control centers for a large oil and gas project in Eurasia. Arc-flash and conventional protection schemes were provided. Manufacturing, testing, and design methods are discussed.
This paper describes the design, technology, model development, and overall validation of a hardware-in-the-loop simulation system for the largest oil and gas project in the world. Lessons learned and results from recent testing are shared.
This paper discusses the implementation of a smart grid system for a large dispersed oil field using radios as its communications network. The solution includes high-speed load shedding, online monitoring, event reporting, oscillography, and engineering access. This paper also discusses the process used to design and test the radio technology, including the evaluation of its success metrics, network security, radio path study, and optimization.
This paper provides an overview of single event upsets (SEUs), including their causes, mitigation methods, and effects on SEL relays. It quantifies the impact that SEUs have on system protection and provides best practices for ensuring reliability.
This paper introduces a deterministic packet transport method of achieving guaranteed latency for critical traffic being transported over packet-based wide-area networks. The method is standard-agnostic, and it elegantly addresses the challenge of migrating time-division multiplexing-based protection circuits to Ethernet without impacting the performance of the network.
This paper explores the implementation of PTP on various Ethernet architectures, including enhancements to provide PTP redundancy. In addition, the paper provides reasons to use PTP clocks and recommendations on the types of PTP clocks to select.
This paper discusses the protection and controls for two parallel 400 MVA (+31.3° to –80.1°) phase-shifting transformers at a utility's 230 kV interconnection substation.
This paper discusses application considerations for communications-assisted line protective relays using five distance zones. This discussion includes how modern microprocessor-based relays can benefit the power system when properly applied to pilot protection and backup step-distance schemes.
Magnetizing inrush creates a spurious operating current in 87T protection. Early 87T relays used harmonics for security during inrush. Today, we can design algorithms that distinguish directly between inrush and fault currents. By using the new algorithms, we improve the sensitivity and speed of 87T protection and maintain security for transformers with cores built from improved steels.
This paper describes an event in which lightning struck a phase conductor of a 345 kV transmission line and discharged current into the phase conductor, but the magnitude of the lightning discharge was insufficient to lead to an insulation breakdown. The paper examines and explains the response of two different line current differential protective relays during such an event.
This paper compares the performance of different third-harmonic schemes and shows how these schemes can be applied to provide secure and sensitive stator winding coverage. It also provides additional guidance regarding learning algorithms and coordination with injection schemes.
This paper reviews three unique CCVT failure events and discusses relay performance during these failures.
This paper demonstrates how electromagnetic torque responses can be used to measure the impact of events on a motor in a power system. The paper shows examples of calculating electromagnetic torque using oscillographic event report data obtained from digital motor protection.
This paper explains how the X/R ratio and the relay operating time affect the asymmetrical current breaker rating. The paper proposes how to derate a breaker for the relay operating time that is shorter than the standard reference relay time of 0.5 cycle. The paper calculates the “rating loss” due to fast tripping and concludes that applying customary margins when selecting breakers may be sufficient to mitigate the effect of ultra-high-speed relays without the need to replace breakers.
This paper highlights the use of symmetrical components for simplifying the analysis of events with non-classic fault waveforms. It first provides a refresher on symmetrical component theory and then analyzes three real-world events using a symmetrical component-based event analysis approach.
This paper describes how CTs saturate in a simple and intuitive way. The paper describes symmetrical and asymmetrical saturation, remanence, the CT equivalent circuit, the CT excitation graph, ANSI ratings, and how to analyze CT performance using simple equations and tools. It then shows how to detect CT saturation in relay event reports and how relay operation can be compromised during CT saturation.
This paper describes a single-ended traveling-wave-based fault-locating method that works with currents only and explains how to perform fault locating manually using ultra-high-resolution fault records from any recording device. This paper also presents laboratory test results as well as field cases in which line crews found the actual faults.
This paper compares the performance of different third-harmonic schemes and shows how these schemes can be applied to provide secure and sensitive stator winding coverage.
This paper examines various options for obtaining bus protection redundancy. The paper includes an emphasis on examining various methods of applying dual relays in an existing high-impedance bus differential CT circuit.
This paper demonstrates how to analyze faulted transmission lines using phase components (Phase A, Phase B, Phase C) as an alternative to symmetrical components (positive-sequence, negative-sequence, and zero-sequence). The paper explores both steady-state and time-domain applications, with emphasis on generating reliable test signals. Advantages of the phase-domain approach are discussed.
This paper explains how microprocessor-based protective relays are used to provide both control and protection functions for small microgrids. Features described in the paper include automatic islanding, reconnection to the electric power system, dispatch of distributed generation, compliance to IEEE specifications, load shedding, volt/VAR control, and frequency and power control at the point of common coupling.
This paper reports on an experimental investigation that uses wavelength division multiplexing in high-performance power system protection applications. The investigation was performed using the latest generation of carrier-grade optical transport network (OTN) equipment. The paper documents the performance, opportunities, and pitfalls associated with this application and outlines practical strategies for the seamless integration of protection systems with the latest generation of OTN technologies.
This paper reviews the merits of controlling autoreclosing based on the location of the fault. Special attention is given to hybrid lines comprising underground cable sections and overhead line sections. The paper explains how the traveling-wave technology allows precise fault locating on these lines and how to use the fault location for autoreclosing for faults on overhead sections and blocking autoreclosing for faults on cable sections.
This paper discusses high-impedance differential protection with respect to applying the scheme with mismatched-ratio CTs. The paper describes methods for accommodating mismatched CTs and reports on high-current laboratory testing of CTs. The testing was performed to assess the risk caused by overvoltage on the end terminal of a higher-ratio CT that was tapped at a lower ratio and connected to a high-impedance differential relay.
This paper explains the principles and illustrates the operation of distance protection including traditional mho and quadrilateral elements, new time-domain incremental quantity distance elements, and future distance elements based on voltage and current traveling waves.
This paper investigates how, by using the communications and reporting capabilities of modern intelligent electronic devices, a continuously running monitoring system can quickly identify and report signal transmission timing or delivery degradation in a protection system using high-speed peer-to-peer signals.
The purpose of this paper is to detail the cybersecurity risks on industrial control systems and discuss how to detect and counter these risks by applying processes and technology to keep these systems safely operating.
This paper discusses the performance comparison of wireless serial and Ethernet communications and innovative wireless network topologies that maximize overall network performance during realistic field conditions. Techniques for simple and inexpensive dual primary data paths are described.
This paper discusses the design specifications and lessons learned from a project that uses computer virtualization to reduce the computing hardware needs for a modern substation.
In an IEC 61850 digital substation, merging units connected to instrument transformers stream analog measurements as data packets via an Ethernet network. This paper proposes applying software-defined networking (SDN) path programming and fast failover features to achieve Sampled Values (SV) stream redundancy. The paper also discusses using SDN to manage an IEC 61850 network by logically separating station bus and process bus traffic using SDN path programming.
This paper discusses the preliminary considerations in designing a micro transactive grid that can be used as a platform to share the investment and return of distributed energy resources with a community.
In this paper, the multi-loop fault analysis method is used to determine the sensitivity and coverage provided by various generator internal-fault protection elements for interturn, interbranch, phase-to-phase, and series faults.
This paper presents common challenges in distribution protection and demonstrates solutions using the multiple protection elements and custom logic available in modern distribution feeder relays and recloser controls. Solutions are provided to prevent false trips due to inrush, improve protection response times, mitigate conductor slap issues, and improve the performance of noncommunicating loop schemes.
This paper shares the initial results and benefits that Blue Ridge Energy Cooperative has achieved by bringing intelligent electronic device oscillography from across their system together in one application.
The need for low-cost technology and the sheer number of individually terminated copper conductors in traditional wiring approaches have long fostered a dream of fully digital secondary systems based on fiber-optic communications technology. This paper provides an overview of recent standards that add to the wealth of knowledge describing this technology, explains various options and the relationship among different standards, and identifies some of the future work required in this space.
This paper discusses how electromagnetic torque can be calculated from oscillographic event report data obtained from digital motor protection. Several example cases are shared.
Numerous digital communications protocols are used in substations to exchange process information traditionally received as low-level analog signals via copper wires from sensors and instrument transformers at the process level. In this paper, characteristics and performance are compared for IEC 61850 GOOSE and Sampled Values messaging, IEC 61158 EtherCAT, IEEE C37.118.2-2011 Synchrophasor Protocol, and Mirrored Bits® communications for their use in copper reduction and distributed communications-assisted control strategies.
This paper presents simple rules for the correct selection of transformer differential relay compensation settings and their application to real-world installations.
This paper describes the components of a Sampled Values system and discusses communications network engineering challenges, solutions, and tools available to provide and verify a reliable Ethernet packet transport in the process bus system. Special attention is given to the design of large substations, which need to securely merge the station bus and the process bus into a single, substation-wide network.
This paper presents a new communications-based protection scheme that uses incremental-quantity and traveling wave-based directional elements to make tripping decisions in 4 to 6 milliseconds. It includes a discussion of forward and reverse fault field events that are used to analyze the performance of a permissive overreaching transfer trip scheme.
This paper describes the challenges associated with protecting pumped storage hydro units. It discusses how digital protective relay schemes provide simpler and more effective protection than traditional electromechanical relay schemes.
This paper describes a single-ended traveling-wave-based fault-locating method that works with currents only and explains how to perform fault locating manually using ultra-high-resolution fault records from any recording device. This paper also presents laboratory test results as well as a field case in which the line crew found the actual fault.
This paper presents transformer protection logic for security during magnetizing inrush conditions, especially under transformer ultrasaturation resulting in low levels of even harmonics in the differential current. The protection scheme includes inrush unblocking logic to accelerate tripping for internal short circuits. The paper explains key principles, shares implementation details, and illustrates the concepts with simulation results and field cases.
This paper explains principles of fault locating based on traveling waves measured only at line terminals for hybrid lines comprising overhead and cable sections. The paper introduces adaptive autoreclosing control logic to allow or cancel reclosing based on the location of the fault. The paper includes examples that explain and illustrate these principles.
This paper describes the challenges associated with protecting pumped storage hydro units and how digital protective relay schemes provide simpler and more effective protection than traditional electromechanical relay schemes.
In this paper, we use the multi-loop fault analysis method to determine the sensitivity and coverage provided by various generator internal-fault protection elements for interturn, interbranch, phase-to-phase, and series faults.
This paper reports on an experimental investigation that uses wavelength division multiplexing in high-performance power system protection applications. The investigation was performed using the latest generation of carrier-grade optical transport network (OTN) equipment. The paper documents the performance, opportunities, and pitfalls associated with this application and outlines practical strategies for the seamless integration of protection systems with the latest generation of OTN technologies.
This paper discusses the advantages of the time frame capacity factor model for utilities in determining the reliability of a power system with integrated renewable energy sources.
This paper develops an error-checking method for analog-to-digital converters (ADCs) and presents test results for a commercially available ADC which indicate that the error-checking scheme is useful for detecting catastrophic data converter failures.
This paper presents an active power control system for a phase-shifting transformer based on mission priorities. The functional design, technical details, system architecture, and implementations of power controllers are discussed. A case study presents the effectiveness of the proposed controllers.
This paper discusses the installation of a rotor angle measurement system that was commissioned for San Diego Gas & Electric. This installation provides real-time monitoring and recording of generator rotor angle as well as field excitation quantities that can be applied to meet MOD-026 and MOD-027 requirements.
This paper presents a communications-based protection scheme that uses incremental-quantity and traveling-wave-based directional elements to make tripping decisions where coupling capacitor voltage transformers (CCVTs) provide voltage signals to these elements. The paper uses field events captured during forward and reverse faults to analyze the performance of the proposed permissive overreaching transfer trip (POTT) scheme, which achieves operating times on the order of 4 to 6 milliseconds.
This paper analyzes event reports that indicated an arcing ground on the neutral end of a large generator. It investigates the limitations of ground protection techniques as well as techniques to overcome these limitations when detecting an arcing ground fault.
This paper describes how Westar Energy implemented a cost-effective distribution automation system that is now providing a very capable and fully automated fault location, isolation, and service restoration and volt/VAR distribution solution.
This paper presents an efficient and systematic approach for evaluating merging units. It offers engineers help, particularly during merging unit testing, in understanding certain characteristics of a merging unit and in gaining confidence with Sampled Values technology.
This paper discusses the complex challenge of achieving seamless transition between grid-tied and island operation of critical facilities while highlighting fast, reliable, and adaptive protection and control solutions.
This paper reviews what can be achieved with a modern controlled switching device in terms of improving power quality, protecting both the power equipment and the breaker, and improving protective relay reliability.
This paper describes the Chess Master project, sponsored by the U.S. Department of Energy, which will apply software-defined networking to advance energy sector network cybersecurity.
This paper describes the modeling benefits, challenges, and lessons learned associated with controller hardware-in-the-loop testing. The microgrid system used in this study has a 3 MW battery, 5 MW photovoltaic array, 4 MW diesel generator set, and 3.5 MW combined heat and power generation system.
This paper proposes a fast, secure, zero-setting adaptive algorithm to detect and declare open line conditions using wide-area synchrophasor measurements.
In an effort to move towards smart grid, the Dubai Electricity & Water Authority initiated a long-term contract for the supply, installation, testing, and commissioning of 33 substations with modern automation systems for transmission power substations. This paper discusses the system requirements and various engineering decisions that resulted from lessons learned during the system design stage to ensure that the system is ready for future smart grid requirements. Various analysis tools and testing techniques are described that were used to quantify the performance attributes of the IEC 61850-based system design.
This paper discusses a practical technique for harvesting the maximum power from a large photovoltaic system. The technique tracks the maximum power point from the nonlinear output characteristics of the PV system using an adaptive neuro-fuzzy inference system (ANFIS) to extract the maximum power from the PV system under different conditions.
This paper demonstrates intelligent electronic device (IED) resiliency to high-altitude electromagnetic pulse (HEMP) events through analysis and test results. It presents substation grounding and wiring practices that are HEMP resilient and also highlights available HEMP standards as they relate to IEDs and substation control houses. This information will help utilities prevent unnecessary mitigation efforts and address the concerns regarding the effects of HEMP on substations and substation IEDs.
This paper provides a basic explanation of time-domain protection and traveling-wave fault location principles and discusses the power system benefits gained from ultra-high-speed protection, precise and fast fault location, and megahertz sampling rates. It also discusses real-world problems solved by applying time-domain technology.
This paper explains a novel data acquisition method that supports accurate, synchronized, wide-area power flow summation at fixed millisecond intervals.
This paper discusses the fundamentals of how to perform isochronous load sharing in an islanded power system with various makes and sizes of generators (steam and gas turbines). The paper details the decentralized generation control system and also presents other topics crucial for industrial power systems.
By using a defense-in-depth approach, you can provide read-only SCADA data and Syslog messages to corporate or other networks. The layered defense includes adding a perimeter network, read-only HMI and Syslog server, and a one-way data sending mechanism through SDN and unidirectional firewall rules.
This paper discusses the benefits of applying the new SEL-FT50/SEL-FR12 Fault Transmitter and Receiver System to enhance distribution system protection.
This paper examines methods available for fault location and describes the method employed at Fayetteville PWC. It shares the results of Fayetteville PWC's pilot project and provides the information to implement their fault location system on the reader's distribution system.
This paper describes the design and testing of the first stage of a synchronism-check upgrade to the Whakamaru Power Station. The scheme allows simultaneous synchronization of up to four 11 kV generators with up to four 220 kV lines located over one kilometer apart.
This paper describes the analysis and resulting investigation that occurred when a CT secondary wire made contact with a transformer bushing, causing an outage at a 138 kV substation.
This paper examines the dynamic mho expansion for positive-sequence memory polarization during a variety of different faults and changing system conditions.
This paper highlights critical parts of the COMTRADE standard and limitations to replaying event files into a relay. It also provides readers a deeper understanding of COMTRADE files and how replaying system disturbances can yield different responses in the protection elements when compared with the original event.
This paper explains practical design principles to follow for networked protection and control systems. Proven cybersecurity best practices, system architectures, monitoring methods, and defense-in-depth techniques are described.
This paper describes two regional system integrity protection schemes implemented in Turkey to avoid regional blackouts and the propagation of disturbances to neighboring countries.
This paper introduces the acceptance criteria for digital messages and LAN performance between data producers and data consumers that are necessary in order to exchange signals to support distributed mission-critical applications. It also compares the attributes of five popular protocols to provide information necessary for designers to understand the behavior and performance of each protocol.
This paper introduces the concept of using terrestrial private communications networks for the distribution of high-accuracy time and provides methods for mitigating specific GPS vulnerabilities.
This paper explains the technical issues that have been addressed during the past decade of Sampled Values technology development and explains how these issues are resolved with the use of software-defined networking for process local-area network packet switching and fault recovery. It also introduces the correlation between accessible electricity and economic improvements, and it discusses the importance of low installation costs, low lifecycle costs, and high availability and resistance for added or expanded power systems.
This paper analyzes the Sampled Value process bus concepts that have recently been updated by various IEC working groups. The authors are engineers with over a decade of participation in developing the IEC communications standards.
This paper describes a three-terminal line differential protection project designed for a rail company as part of a refurbishment project. The paper explains each of the different technologies used for this project, including line differential over Ethernet, coarse wave division multiplexers, and managed switch configuration. It also provides details of the performance of the system in terms of speed and stability.
This paper presents actionable information regarding the critical requirements of a fully trusted industrial control system network. It examines the strengths and weaknesses of existing solutions for implementing trust management.
This paper summarizes the Ethernet packet performance time definitions in IEC 61850 Edition 1 and the new IEC 61850 Edition 2 time classes, introduces subscribing device features required to confirm proper packet exchange, and illustrates case study examples of in-service local-area network (LAN) failures.
The principles of software-defined networking (SDN) offer significant benefits for operational technology (OT) networking by addressing the limitations of traditional Ethernet. Read more in this white paper.
Southern California Edison is protecting a new 500 kV mutually coupled transmission line incorporating both overhead and underground sections. This paper discusses the protection challenges faced with this type of arrangement and describes using real-time digital simulation to evaluate the performance of the protection system.
This paper explains how commercial, off-the-shelf protective relays can be used to automatically island microgrids and to then automatically reconnect them to the macrogrid.
This paper outlines the benefits of using digital communications between primary substation equipment and the protective relays installed in the control house. The authors discuss two methods used to implement a process bus—a switched network and a point-to-point network—and then introduce a new point-to-point, EtherCAT-based digital substation technology that is robust, simple to use, and secure.
This paper describes the components of a wireless protection sensor system, its integration with protection devices, and how the fault information can be transmitted from the sensors to such devices at protection speeds. Additionally, this paper discusses how protection devices use this low-latency fault information to securely speed up the operation speed of and improve the selectivity of distribution protection schemes.
This paper discusses the functionality and merits of the high-speed distribution protection implemented for the City of College Station's multiple distribution substations using communications-assisted special protection and control schemes. These schemes were implemented to improve the reliability, selectivity, and availability of the power system.
This paper describes an event in which a negative-sequence overcurrent (51Q) element operated for a fault on an adjacent feeder, discusses the impact of voltage unbalance on induction motors, and shares lessons learned to assist engineers to securely set 51Q elements.
This paper provides procedures and guidelines for successfully designing and integrating IEC 61850 GOOSE protection schemes while keeping the feasibility of initial commissioning and future expansion and testing in mind.
This paper discusses motoring events and the resulting active and reactive power flows, examines existing reverse power relays used for generator protection, and presents a new algorithm for dependable motoring detection. It also reviews current transformer and voltage transformer accuracy as defined by ANSI IEEE C57.13 and IEC 61869.
This paper outlines the three distinct advantages that software-defined networking (SDN) brings to Ethernet-based control systems: dramatically improved packet delivery performance under both normal and fault event conditions, greater cybersecurity without added complexity, and centralized situational awareness with disruptionless change control, enabling seamless scalability.
This paper details a system developed with American Electric Power for monitoring and automatically diagnosing the health of circuit breakers. It presents an overview of real-time data parameters recorded to provide important health diagnostic information that provides insight into the remaining expected life of the breaker. The system uses this information to reduce operations and maintenance costs by eliminating regularly scheduled manual tests and shifting to as-needed maintenance rather than regularly scheduled maintenance.
This paper compares the intrinsic performance of conventional mho elements and incremental quantity-based distance elements, irrespective of the ways they are implemented. Specifically, it explains that incremental distance elements have superior performance, but they have to be supplemented by conventional mho elements because the incremental elements are only available for a short time.
This paper describes the design of a system that combines event files stored in protective relays and synchrophasor data streamed from phasor measurement units (PMUs) for wide-area system analysis.
This paper describes the design, construction, and commissioning of the microgrid controls for the Duke Energy McAlpine Creek microgrid project and the lessons learned from its implementation.
In this paper, we use high-resolution event data to discuss switching surges caused by high-speed reclosing on high-voltage lines and their impact on bus differential relays.
This paper introduces new ideas and concepts that complement existing generator protection elements to provide better overall generator protection and monitoring.
This paper describes the practical implementation details and operational experience of a new oscillation detection system initially operated at San Diego Gas & Electric. Several examples are provided of successful detection and analysis of events using this system.
This paper addresses the use of IEC 61850 network engineering and testing guidelines for performing network acceptance testing and for troubleshooting in-service Ethernet networks. The paper also explains best practices to configure systems to constantly perform self-tests and monitor and record performance statistics.
This paper discusses improvements to out-of-step protection. These improvements provide adaptive protection based on dynamical system energy balance to more effectively detect potential out-of-step conditions and provide more flexible corrective actions. This method also provides additional robustness by compensating for uncertainties in system parameters.
This paper presents a centralized microgrid control system for effective operation of wind turbines and diesel engines coupled to a flywheel electrical storage component on Saint Paul Island. The wind turbines have sufficient capacity to support the entire island without using the diesel engines, allowing the formation of an islanded power system completely powered by renewables. The control system was tested using hardware-in-the-loop simulation with a simplified electrical model of the Saint Paul system.
This paper provides a brief overview of SEL’s Time-Domain Link Technology (TiDL) and IEC 61850 as digital substation solutions and assesses the cybersecurity posture of each.
This paper discusses what happens when a microgrid control system fails and quantitatively evaluates the impact on microgrid reliability.
This paper describes the authors’ experience in designing, installing, and testing microgrid control systems.
This paper describes the logic design, communications infrastructure, and real-time testing of a remedial action scheme implemented in southern Peru.
This paper reviews a number of typical settings found in incremental quantity- and traveling-wave-based protection elements and provides setting guidelines and examples for various applications, including series-compensated lines and lines with tapped loads.
This paper provides insights into how mutual coupling affects ground distance, ground overcurrent, and directional elements in different system configurations; offers practical advice for identifying situations where mutual coupling must be considered; and provides step-by-step guidance for setting ground distance and directional overcurrent elements on transmission lines that are affected by mutual coupling.
This paper focuses on defining and measuring the performance of ultra-high-speed line protective relays, including traveling-wave protection elements.
This paper discusses relay testing concepts, using a line distance relay element as an example.
This white paper describes the early days of programmable logic controllers (PLCs), the introduction of Modbus protocol, and some of the challenges involved today with device interoperability, specifically challenges related to register addressing and data type formatting.
This paper describes a defense-in-depth scheme that applies specifically to the industrial control system realm, with implementation details and an example system.
This paper provides a clear set of procedures and equations to follow in optimal current transformer selection for low-voltage motor control centers.
This paper summarizes the successful addition of a remedial action scheme to an in-service emergency control system in the country of Georgia.
This paper explains a novel data acquisition method that supports accurate, synchronized, wide-area power flow summation at fixed millisecond intervals.
This paper discusses how to use event data (voltages, currents, and fault location) from relays at two ends of a transmission line to calculate positive-, negative-, and zero-sequence line impedances. Impedances calculated from real event data can be used to validate relay settings and short-circuit models.
In this paper, we briefly discuss the types of underground cables, their bonding and grounding methods, and the fundamental differences between overhead transmission lines and cable electrical characteristics. Finally, we discuss the application of short-circuit protection for high-voltage ac cables.
This paper proposes a new principle for generator turn-to-turn fault protection based on the ampere-turn balance between the stator negative-sequence current and the double-frequency component of the field current. The paper describes two protection elements using this principle: a stator-rotor current unbalance element that uses the current magnitudes and a stator-rotor current differential element that uses the current phasors. The paper derives the new methods, discusses their dependability, sensitivity, and security, and illustrates their operation with computer simulations and test results from a physical made-to-scale generator.
This paper provides eight basic guidelines to improve cybersecurity for industrial control systems.
This paper analyzes the voltage sags that occurred during a simulated transformer energization study for an offshore platform.
This paper describes the impacts of photovoltaic (PV) installations on power systems and discusses different mitigation methods to address them. The paper proposes a solution to minimize the impacts by using the concept of coordinated control between the substation and the PV generation plant.
This paper describes the implementation of a power management system for a mature oil field facility and how the system was optimized to use utility generation, its own generation, or both combined for the reliability, stability, and scalability of the facility power system.
This paper demonstrates that errors will exist with a conventional single- or double-ended fault location calculation if the fault occurs during a pole-open condition. Compensated algorithms are presented that achieve accurate fault location under these conditions.
This paper proposes a modular microgrid unit (MMGU) that can work autonomously but is also capable of connecting to other MMGUs to form an expandable microgrid.
In this paper, a real-world event and simulations are used to study the impact of dc winding resistance testing on the magnetizing current of a transformer. Solutions are provided to mitigate possible unintended operations.
This paper describes a new falling conductor detection scheme that trips the affected circuit section in the narrow time window between the moment of the break and the time the conductor hits the ground. The affected circuit section is de-energized while the conductor is still falling, eliminating the risk of an arcing ground fault or energized circuits on the ground.
This paper discusses the design and implementation of a distribution automation system developed to detect electric faults using fault indicators and automatically reconfigure the distribution system topology to isolate faulted sections and restore service to the de-energized loads.
This paper discusses protection system designs for three single-phase-and-spare transformer banks. Ways to improve sensitivity and make it possible to precisely indicate the fault location in the bank are illustrated with examples. The paper also discusses how to design the system to easily reconfigure the differential zones for any spare substitution configuration.
This paper is an introduction to the deployment of a network intrusion detection system for industrial control systems.
Two drastically different types of differential relays, one with a single set of very high-impedance inputs and another with multiple sets of low-impedance inputs, are available for bus differential protection. This paper discusses for each type of relay the concepts used, the pros and cons, and the importance that current transformer selection plays in applications.
This paper discusses improving the security and dependability of line current differential protection schemes on series-compensated transmission lines prone to current inversion.
This paper describes the protection challenges and solutions associated with the Penonomé wind power plant in Panama. The paper discusses protection coordination requirements and results, provides recommendations for future enhancements of the protection system, and concludes with a description of an actual event involving two cross-country faults in a 34.5 kV system.
Ultra-high-speed line protection is becoming a reality today, giving the industry a way to trip line faults in a few milliseconds. One relay described in this paper that uses time-domain principles incorporates incremental-quantity (TD32) and traveling-wave (TW32) directional elements in a communications-assisted tripping scheme, incremental-quantity distance element (TD21), and traveling-wave differential element (TW87). This paper introduces these time-domain line protection elements, shares key details of their implementation in hardware, and illustrates their operation using real-world faults and digital simulations. By comparing the performance of the time-domain line protection elements with the traditional phasor-based elements of the in-service relays that captured the fault records, we demonstrate the performance of the time-domain line
This paper explains modern nanosecond precision time technologies and new applications they enable.
This paper describes and evaluates several commonly applied line protection schemes using analysis tools like fault trees, power system studies, and event analysis. The paper compares the protection schemes in terms of speed, sensitivity, security, dependability, and selectivity.
This paper analyzes and explains why the compensator phase distance elements operated for a utility that experienced a phase cross-connect condition when personnel inadvertently crossed two phases during line switch installation. This paper also discusses the theory of operation of compensator phase distance relays and methods for making elements secure in similar phase cross-connect conditions.
This paper describes the effect geomagnetically induced currents have on CTs and the resulting impact on protection security and dependability. The paper supports its claims with simulated as well as experimental results.
This paper discusses the installation and commissioning of a generator rotor angle and field quantities measurement system at a 740 MVA combined cycle plant. The paper discusses the lessons learned and possible applications using these measurements.
This paper describes the communications requirements for various protection and control applications, and it discusses the advantages and disadvantages of communications technologies. The paper also describes how network topologies can improve security and dependability, and it discusses cybersecurity practices that are suitable for securing protection communications links.
This paper details the threats that SCADA and industrial control systems face, how to detect and counter those threats, and how to apply countermeasures, new technologies, and safe practices to these systems.
This paper describes the post-fault analysis following a three-phase intercircuit fault on parallel 138 kV transmission lines. Fault study data associated with single fault conditions on each line are compared with time-synchronized disturbance data from protective relays.
This paper provides an overview of winding insulation failure modes related to ground faults and discusses all common ground fault protection schemes in detail. The paper contrasts the following aspects of these schemes: sensitivity, speed, security, availability, complexity, and setting considerations.
This paper discusses the implementation of a fast motor bus transfer scheme using existing protective relays. The scheme is designed to respond to local and remote (upstream) events in the substation. This makes possible an attempt to initiate a fast transfer for events that are remote to the motor bus. On a failure to achieve a fast transfer, the scheme resorts to an in-phase transfer and, if that fails, finally a residual transfer. Real-time dynamic modeling was performed to simulate motor bus decay and reacceleration. This paper provides the results of the simulations and the response of the transfer scheme.
This paper provides explanation and comparison of methods of fault identification, isolation, and recovery of data paths in Ethernet networks for high-speed automation and protection applications. SDN is introduced as a new and improved Ethernet transport technology for mission-critical applications.
This white paper discusses SEL Real-Time Automation Controller (RTAC) security concepts and provides configuration examples to empower engineers, technicians, and security personnel to protect critical cyberassets.
This white paper describes how to use the SEL Real-Time Automation Controller (RTAC) to build an automated system to continuously monitor and validate many of the components identified in the NERC PRC-005 standard.
This paper shares details about three challenging case studies and their root causes.
This paper compares the results of using two different wireless technologies, serial radios and cellular modems, to simultaneously stream synchrophasor data from four different locations along a rural feeder to a photovoltaic generation site.
This paper discusses Phase 2 of the ongoing distribution automation pilot project by Central Lincoln People's Utility District, focusing on the fault indicators used in the project and highlighting lessons learned.
This paper describes the new high-speed data acquisition and precise synchronization strategies used for the design of the communications network required for an HVDC link between Spain and France. Various contingency scenarios to improve the availability and reliability of the system are discussed along with several new hardware and software redundancy methods to improve the overall control system dependability and security.
A centralized series of dual triple modular redundant special protection systems have been implemented in Taiwan. This paper covers their design, testing, and implementation.
This paper describes a new directional power algorithm in the form of an adaptive characteristic that provides a dependability bias to ensure tripping during an inadvertent motoring event.
This paper illustrates the methods and benefits of supervising the timely and accurate receipt of GOOSE messages and calculating a binary logic representation of the success of digital message exchange of protection signals. This status, referred to as message quality, is used as a qualifier in communications-assisted protection and automation logic to adapt the logic immediately after communications fail.
This paper analyzes the performance of CTs under the presence of geomagnetically induced currents (GICs). The paper proposes a simple CT model to analyze the GIC problem and applies it, as well as laboratory tests on a physical CT, to explain and quantify the impact of GICs on CTs. We conclude that the impact to protective relays is minimal.
This paper describes new special-purpose test devices and procedures to verify Ethernet network configuration and performance. The results of research using these test procedures are explained, which reveal new network topology recommendations and associated configuration recommendations for protection signal messages, such as multicast GOOSE messages.
This paper describes the shortcomings of PRP and HSR and how to create Ethernet redundancy and duplication via software-defined networking (SDN). Examples illustrate how SDN methods create lossless signal delivery (with the use of Ethernet packets) and address issues of teleprotection, interlocking, and automation applications based on IEC 61850 GOOSE messaging.
This white paper addresses the design considerations for modifying transformer protection at an existing nuclear station and the SEL equipment that can be used to implement that design.
This paper provides guidance to transmission system operators and protection and control engineers on how to overcome the technical limitations imposed by traditional technology for synchronizing islanded microgrids with advanced technology.
This paper briefly explains the principle of ground fault detection in an ungrounded power system and the challenges of locating the actual faulted feeder on the LADWP distribution system at present. We then discuss a new innovative algorithm developed to correctly identify the faulted feeder on the LADWP distribution system. We validated this algorithm by means of laboratory and staged-fault field testing.
This paper presents a country-wide remedial action scheme (RAS) implemented in Usinas y Trasmisiones Eléctricas (UTE) in Uruguay. The RAS consists of six different schemes operating independently and, in certain cases, simultaneously to calculate power system states and take the remedial actions.
This paper compares the mechanisms for quickly reconfiguring Ethernet networks to satisfy mission-critical performance metrics while providing simultaneous duplicate or redundant signal exchange. The paper also describes the redundancy and duplication methods that are available in software-defined networking.
This paper addresses the use of IEC 61850 network engineering and testing guidelines for troubleshooting Ethernet networks. The paper shares practical examples of detecting problems, finding root cause, and correcting communications problems in operational systems in South Africa, Asia, and Europe.
This paper explains why new design possibilities provided by modern IEDs make it difficult to describe protection and control system functionality using traditional schematic diagrams. The paper describes one utility's experience as they worked to modernize their logic and documentation, and it discusses the new guidelines they developed and adopted for logic diagram creation.
This paper is a case study describing the implementation and testing of an advanced automatic synchronising system for a complex and flexible 330 kV bus arrangement used for connecting two hydroelectric generating stations to the transmission grid.
This paper presents the advanced solutions implemented for the protection of a crucial metropolitan distribution network that consists of several parallel circuits between a single-source substation and two load-serving substations.
This paper studies the failures of substation automation systems (SASs) and proposes an all-inclusive categorization of failures that are likely to endanger the correct operation of a power system. Understanding different failure modes can contribute to the development of a model to evaluate the combined SAS and power network in a unique framework.
This paper describes a point-on-wave model development and simulation study that supports a broader investigation of the effect of air conditioning and similar loads on the recovery of electric utility voltage after faults.
This paper summarizes present protection recommendations and their limitations for the three most common types of PSTs. The paper then reports on the further development of a differential element that has been in successful use for many years, is sensitive to all fault types (including turn-to-turn faults), and can be applied to any type of PST using only CTs on the source and load sides of the PST zone.
This paper compares the mechanisms for quickly reconfiguring Ethernet networks to satisfy mission-critical performance metrics while providing simultaneous duplicate or redundant signal exchange. This paper also compares the attributes and complexities of duplication methods and redundancy methods that are available in software-defined networking (SDN) to create lossless signal delivery with the use of Ethernet packets and address issues of teleprotection, interlocking, and automation applications based on IEC 61850 GOOSE messaging.
This paper illustrates the benefit of measuring I0p (the parallel line zero-sequence current) for fault location.
This paper reports on advanced synchronizing systems installed on two offshore platforms.
This paper provides a description of the requirements for protection-class Ethernet networks and the benefits of using software-defined networking (SDN) technology over traditional networking.
In the interest of reducing communications misoperations, this technical paper shares practical lessons learned through experience with troubleshooting, diagnosing, and correcting in-service Ethernet networks. These examples are important for all users and designers of Ethernet communications to review because they represent mistakes that are easy to make, hard to diagnose, and difficult to correct after the fact.
This paper presents methods for supervising signal exchange via digital messages. Case studies that provide examples of improvements to applications, such as logic selectivity, circuit breaker failure (50/62BF), and automatic line transfer (ALT) based on signal message supervision, are discussed.
This paper identifies how accurately loads must be modeled, specifically for frequency stability studies. It also provides a simple reference that engineers can use to specify the level of detail required when load modeling industrial power systems.
This paper shares the methods used to find root cause and solve a governor-induced frequency instability problem.
This paper discusses a fully redundant power management system for a major oil field in Saudi Arabia with a production capacity of 750,000 barrels of oil per day.
This paper provides a theoretical view of how ungrounded and grounded systems behave as well as techniques for providing proper protection for both. It discusses a case study in which a particular system can change between effectively grounded and ungrounded and remain in service.
This paper discusses the line parameter estimation methods for underground cables and presents results from field data and simulations.
This paper presents the functionality, validation, and performance of a state-of-the-art islanding detection and decoupling system in a simulated model for a real-world application.
This paper discusses the implementation of high-speed islanding detection and zone interlocking schemes at a North American refinery using automation controllers. It discusses the scheme layout, protocols used, and algorithms developed to integrate the schemes to achieve optimal performance.
This paper provides field cases that investigate protection system performance when systems are subjected to unexpected switching or interruptions in dc or communications links.
This paper describes a smart automatic synchronizing system that can connect multiple generators in an industrial power system during islanded and utility-connected modes via six different bus-tie and utility tie breakers. The automatic synchronizing system performs matching by controlling multiple governor and exciter interfaces within the facility.
This paper describes the objectives and operating principles of a centralized and automated underground distribution automation system (UDAS) that was developed and applied for rapid fault detection, isolation, and service restoration.
In this paper, the effect of breaker pole scatter on quadrilateral ground distance elements is investigated using a simple two-source power system with two short transmission lines. A case study is included.
This paper discusses complications that can arise from paralleling current transformers and highlights relay design improvements that have been made to add security to these applications.
The paper discusses the benefits of integrating modern substations with a scalable enterprise approach to ensure consistency among substations for operations maintenance and quicker deployment while reducing costs and increasing cybersecurity. Application examples are included.
This paper looks at various commonly used transmission line protective elements and points out characteristics of the line and system to look for when standard reaches and margins cannot be used.
Today's relays are predominantly based on phasors, and as such, they incur a delay associated with the full-cycle observation window required for accurate phasor estimation. This paper discusses a number of protection techniques based on incremental quantities and traveling waves that significantly speed up line protection.
This paper is a transcript of a panel session discussing the relationship between regulators and operators. Panel participants included representatives from Lower Colorado River Authority, the North American Electric Reliability Corporation, Texas Reliability Entity, a law firm, and the National Transportation Safety Board.
This paper explains the principles of negative-sequence differential protection, its basis for excellent sensitivity and speed, and the need for securing it with external fault detectors to deal with the saturation of current transformers. The paper also derives two new protection principles based on negative sequence for generator turn-to-turn fault protection.
This paper presents guidelines developed by CFE to improve and standardize generator protection. Based on the results of simulations and field experiences, the paper describes setting guidelines and improved protection schemes for loss-of-field (40) and stator ground fault (64G) protection.
In this paper, we use gathered event reports to analyze an intercircuit fault that occurred multiple times between two separate voltage levels after a snowstorm. Also discussed are improvements to relay performance during intercircuit faults, including line current differential.
This paper presents the fault current characteristics of a Type 4 wind turbine generator, a case study of a misoperation of directional overcurrent relays in a wind power plant, and recommendations for protecting wind power plants.
This paper teaches how to calculate the source impedance ratio to classify the electrical length of a transmission line for determining protection requirements and setting criteria.
This paper discusses the design and implementation of a system that delivers wide-spectral bandwidth data with precise time stamps over a wide area.
This paper explores technology options for extending local-area networks (LANs) to devices in a substation yard by using wireless technology.
This paper provides a general overview of out-of-band management technology and discusses how it can be applied to a SCADA system to allow remote maintenance of network and computer assets, reduce costs, and improve system reliability.
This paper shows how time-division multiplexing (TDM) and Ethernet communications can be integrated to leverage the benefits of each technology. It also evaluates communications-assisted relay protection schemes and considers future relay protection methods.
This paper investigates the benefits that whitelist malware protection provides power systems and shows that correctly combining malware protection and embedded architecture improves the reliability and cost of ownership of the whole system.
This paper discusses ways to overcome undesired tripping on distribution feeders on inrush conditions using both settings changes and second-harmonic blocking.
This white paper addresses the two main reliability concerns in NAND flash storage, what type of NAND flash memory is best suited for embedded computer systems, and how to optimize computer systems for maximum reliability of NAND flash storage.
This paper describes the development of a new Pacific Gas and Electric Company (PG&E) 500 kV transmission line and breaker protection standard, including the motivations for embarking on the project, challenges encountered, and lessons learned during the design effort.
This paper discusses the replacement of the existing motors at a major gas plant in Saudi Arabia with 27,000 hp synchronous motors. It discusses in detail the thermal model selection, custom thermal protection, relay settings, and the coordination study for these motors.
This paper discusses the centralized ground fault detection system for the LADWP ungrounded distribution system. It explains the ground fault detection of ungrounded distribution systems and innovative algorithms developed to identify ground faults, as well as laboratory test and staged-fault field test results.
This paper describes an ac railway electrical distribution system and the challenges associated with the protection of its feeders.
This paper takes an in-depth look at the injection-based stator ground protection principle, reviews state-of-the-art techniques, and reports on a standalone injection-based relay capable of offering 64S 100 percent stator ground protection all of the time.
This paper discusses a generator percentage differential element that uses external event detection logic to provide additional security for external events without sacrificing dependability.
This paper provides a discussion of event analysis and complex faults, along with a few key characteristics to assist in analyzing event report data generated by a complex fault. Finally, an in-depth analysis of a complex intercircuit fault that occurred on the LCRA TSC 138 kV system is provided.
This paper describes a case study of using IEC 61850 GOOSE messaging to simplify lockout and breaker failure tripping in a 345 kV wind generation integration substation.
This paper describes the development of a control system that applies local information in coordination with synchrophasor measurements to assess the complete state of the power system and differentiate a local phenomenon from the possibility of an overload-related cascade.
This white paper provides both theoretical and real-world examples with questions and solutions that can be used to gain experience with symmetrical components.
This paper explains the basics of how steam turbines produce power, how they are controlled for extraction and droop, and how governors provide dynamic disturbance rejection in an electric power system. This paper shares a case study project at a refinery and includes discussion of steam control, turbine speed and power control, adaptive boundary conditions, extraction turbine basics, and autosynchronization.
This paper introduces a reliable islanding detection solution, using multiprinciple detection techniques and voting supervision logic, that was proposed, implemented, and tested at a refinery in Texas.
Currents associated with balanced and unbalanced faults through three-phase transformers with various combinations of delta and wye windings are reviewed in this paper and used to develop alternative transformer differential relay testing methods using existing relay test sets with two or three current outputs.
Using dissimilar relays in a pilot scheme presents coordination difficulties due to different operation principles that result in different sensitivities, speeds, and transient responses. This paper presents problems and challenges discovered in real-world applications of dissimilar relays in a pilot scheme. The paper also presents solutions to minimize the risk of misoperation and achieve good fault coverage.
This paper proposes a method to measure transmission line parameters for protective relay settings. This method relies on synchronized phasor measurements taken at both ends of the line and compares them with the calculations from both the equivalent PI circuit and the distributed constant line parameters.
This paper contains illustrations of test methods in IEDs and test devices to verify the performance of Ethernet networks as previously described in the paper "Design and Validation Practices for Ethernet Networks to Support Automation and Control Applications."
The Lower Colorado River Authority (LCRA) is protecting a series-compensated line on their transmission grid for the first time as part of the Competitive Renewable Energy Zone (CREZ). This paper discusses experiences in designing, setting, and validating the new protection system.