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This webinar explains CT saturation in an intuitive way using simple animations and avoiding complex math and physics. We examine symmetrical and asymmetrical saturation, remanence, the equivalent circuit of a CT, and CT excitation graphs. We also…
Through analysis of event reports recorded by relays, this paper will present several examples of settings that led to unintended operation of distribution protection, including transformer delta-winding residual overcurrent protection, transformer high-voltage phase overcurrent protection, and others.
In the interest of reducing transformer differential misoperations, we share in this technical paper practical lessons we have learned through experience with commissioning and relay event report analysis.
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 the interest of reducing transmission line relay misoperations, this technical paper shares practical lessons learned through experience analyzing transmission line relay event reports.
This paper investigates several real-world events with data from both motor starting reports and event records. The data demonstrate the value of having devices capable of recording motor data during starts and fault events and of capturing and reviewing such data for the purpose of determining root cause.
This paper analyzes real-world event report data in the interest of uncovering valuable lessons for setting and commissioning generator relays.
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 presents a novel approach to frequency estimation for power system applications: frequency tracking, frequency protection, and synchrophasors. We based our algorithm on autocorrelation of the waveform or correlation of the waveform and its derivative using a freely chosen window length. Because of the averaging inherent in correlation, the method has exceptional immunity to noise. We derive, explain, and illustrate the new method with simulation results. We review advantages and attributes of the new method compared with two commonly used approaches to frequency measurement: timing between the waveform zero crossings and measuring the rate of rotation of a phasor.
This paper reviews new time-domain line protection operating principles using traveling waves and incremental quantities. We discuss operating principles of novel directional and differential elements based on traveling waves and Zone 1 distance and directional elements based on incremental quantities. This paper provides details on the actual implementation of these principles in a high-performance relay platform and shares performance results from simulations and field recordings.
This paper explores technology options for extending local-area networks (LANs) to devices in a substation yard by using wireless technology.