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The operating equations for key phasor-based protection elements of the SEL-T401L Ultra-HighSpeed Line Relay are published in Appendix G: Signal Processing and Operating Principles of the SEL-T401L Ultra-High-Speed Line Relay Instruction Manual. These equations define the behavior of the protective elements and, when simulated in software, create a simplified model of the key phasor-based protection elements that can be used to better understand relay operation. Note that this model is only an approximation of the behavior of the relay.
This application guide shows how to calculate and test the operating time of inverse-time overcurrent protection elements. Use the accompanying spreadsheet to calculate curve operating times based on relay settings and applied current.
Application Guide - This application guide demonstrates steady-state, single-phase testing of the SEL-487E Transformer Protection Relay differential element and does not require state simulation. For a complete reference on testing this relay, refer to SEL Application Guide AG2010-07 .
Application Guide - This application guide provides an example of using basic information about the motor and power system to model the performance of the machine during starting.
This application guide shows how to reduce effort and complexity when performing common device management tasks (such as upgrading firmware) for the SEL Real-Time Automation Controller (RTAC).
This application guide provides a brief overview and then explains the core concepts of QuickSet Design Templates through several Job Done® examples of increasing difficulty. Each completed example is included in an .rdb file that accompanies this application guide.
Application Guide - This application guide describes a test procedure for the thermal element in the SEL-710 Motor Protection Relay and provides test parameters using specific relay settings. While this application guide specifically addresses the SEL-710, the same procedure can be used for testing other SEL motor relays. The instruction manual for each relay includes details on the specific thermal model used. The test procedure outlined is applicable for SEL-710 Relays with firmware version R200 or newer.
The SEL-451 Protection, Automation, and Bay Control System has extensive logic and protection features, allowing it to be used for many applications. This application guide describes how to implement a motor bus transfer scheme in the SEL-451 for a two-source configuration.
Application guide - The SEL-121F, SEL-121S, SEL-121-0, SEL-221F, SEL-221S, and SEL-221-16 Relays were designed in the 1980s and include phase and ground distance elements. There is not enough processing power in an eight-bit microcontroller to check all of the distance elements (AB, BC, CA, AG, BG, and CG) for each zone during every one-quarter-cycle processing interval. Therefore, these relays use a method for faulted phase identification that is described in this application guide.
This application guide shows how the custom calculation engine in synchroWAVe Event Software can be used to plot the compensated currents and operate and restraint quantities for any SEL transformer protection relay.