ℹ️ Document Conversion Notice: This document has been converted from PDF and formatted to fit this screen. Diagrams and images may be available only in the original here.

An SEL Approach to Modifying Transformer Protection for Nuclear Stations

By Larry Wright

Introduction

Nuclear power generating stations face unique challenges when updating their protective relaying systems due to aging equipment and the need for enhanced functionality. This white paper from Schweitzer Engineering Laboratories (SEL) explores modifications to transformer protection, specifically for Generator Step-Up (GSU) transformers, Unit-Auxiliary Transformers (UATs), and Station-Service Transformers (SSTs). It details design considerations and highlights the capabilities of SEL equipment in addressing these upgrades.

General Design Considerations

When upgrading protection in nuclear stations, a strong emphasis is placed on security and the elimination of single-point vulnerabilities. This often leads to the consideration of redundant two-out-of-three voting schemes, which offer increased security compared to traditional dual-redundant schemes, despite a potential slight decrease in dependability and a moderate cost increase. SEL recommends using a single model of transformer relay for consistency and reliability in redundant schemes.

Relay Selection

The SEL-487E Transformer Protection Relay is highlighted as a robust solution for large generating stations due to its speed, security, and comprehensive features. The paper provides an overview of its functional capabilities, including various protection elements such as differential, overcurrent, and thermal monitoring.

Function Selection and Wiring Design

The document discusses the strategic selection of protective functions within the SEL-487E to optimize performance, including harmonic blocking, negative-sequence differential elements for turn-to-turn faults, and restricted earth fault elements. It also covers AC and DC wiring design considerations, emphasizing the benefits of microprocessor-based relays in simplifying installation and reducing wiring complexity. The paper also touches upon communication protocols like MIRRORED BITS and Ethernet for enhanced system integration.

Maintenance and Conclusion

SEL's approach to maintenance for microprocessor-based relays is simplified, with an emphasis on commissioning tests and monitoring self-test alarms. The paper concludes that upgrading existing nuclear plant transformer protection with the SEL-487E offers significant benefits in terms of reliability, security, and functionality, with similar advantages achievable across other areas of the plant through SEL's protection and communication products.

Google Docs
Google Drive
Download [pdf]
File Info : application/pdf, 12 Pages, 2.34MB
Document Document

0017 SELApproach LW 20151117 Adobe PDF Library 11.0

Related Documents

	SEL-T401L Ultra-High-Speed Line Relay: Dependable Protection Discover the SEL-T401L, an advanced line protection relay offering ultra-high-speed time-domain protection, traveling-wave fault location, and high-resolution transient recording. Learn about its features, applications, and benefits for modern power systems.
	SEL-FLT and SEL-FLR: Fault and Load Monitoring System for Distribution Reliability Schweitzer Engineering Laboratories (SEL) offers the SEL-FLT Fault and Load Transmitter and SEL-FLR Receiver System for enhanced distribution system reliability, fault detection, and load monitoring. Learn about its features, applications, and specifications for power utilities.
	SEL-411L Current Differential Relay Datasheet Datasheet for the SEL-411L Current Differential Relay, detailing its features, firmware options, power supply, secondary inputs, communication protocols, Ethernet options, serial line communications, mounting, chassis, I/O boards, and accessories.
	SEL-751 Feeder Protection Relay: Advanced Power System Protection Discover the Schweitzer Engineering Laboratories SEL-751 Feeder Protection Relay, a robust solution for comprehensive feeder protection, fault location, and arc-flash detection in power systems. Learn about its advanced features and applications.
	RTAC R153 Technical Note: Firmware Enhancements and New Features This technical note details the new features and enhancements introduced in firmware version R153-V0 for the Schweitzer Engineering Laboratories (SEL) ACSELERATOR RTAC product line. It covers cybersecurity improvements, network event capture, temporary licensing, Modbus server enhancements, Axion touchscreen capabilities, and new library extensions.
	Schweitzer Engineering Laboratories S.r.l. Product Sales Terms and Conditions This document outlines the terms and conditions for the sale of products and services by Schweitzer Engineering Laboratories S.r.l. (SEL) to its buyers, covering aspects like contract terms, definitions, pricing, payment, delivery, intellectual property, warranty, liability limitations, and dispute resolution.
	SEL-735 Power Quality and Revenue Meter: Features, Specifications, and Applications The SEL-735 from Schweitzer Engineering Laboratories is a high-accuracy power quality and revenue meter designed for advanced metering, waveform capture, and grid stability monitoring. It offers robust features for industrial and utility applications, including precise energy measurement, comprehensive data logging, and flexible communication options.
	Schweitzer Engineering Laboratories S.r.l. General Terms and Conditions of Product Sale This document outlines the General Terms and Conditions of Sale for products and services provided by Schweitzer Engineering Laboratories S.r.l. (SEL). It covers aspects such as sales conditions, definitions, pricing, payment terms, delivery, intellectual property, warranty, indemnification, limitations of liability, and dispute resolution.