Purposes of Protection Coordination

Purposes and Objectives of Protection Coordination Study

The objective of the protection coordination study is to ensure that all protective devices within the system, including relays, breakers, and fuses, are properly coordinated and appropriately sized relative to the equipment they are designed to protect.

The benefits of conducting a protection coordination study are as follows:

  • Enhanced system and facility reliability
  • Reduction in the financial impact of disruptions
  • Improved protection for equipment
  • Increased operational efficiency
  • Assistance in operations and minimization of unnecessary downtime
  • Identification and prevention of damage due to underrated equipment
  • Identification and prevention of breakdowns due to overloaded equipment

In a well-coordinated system, protective devices are selected and configured to minimize the adverse effects of equipment interference. A coordination study involves analyzing the characteristic curves of fuses and breakers, and comparing these on a log-plot. This comparison reveals any miscoordination, indicated by overlapping curves of different protective devices, thus allowing for necessary adjustments to ensure optimal performance.


How to Conduct Relay Protection Coordination Study?

Reference Standard

  • IEEE 141 – Recommended Practice for Electric Power Distribution and Coordination of Industrial and Commercial Power Systems
  • IEEE 242 – Recommended Practice for Protection and Coordination of Industrial and Commercial Power Systems
  • IEEE 399 – Recommended Practice for Industrial and Commercial Power System Analysis
  • IEEE 241 – Recommended Practice for Electric Power Systems in Commercial Buildings
  • IEEE 1015 – Recommended Practice for Applying Low-Voltage Circuit Breakers Used in Industrial and Commercial Power Systems.
  • I­dEEE 1584 – Guide for Performing Arc-Flash Hazard Calculationsl
  • ANSI C57.12.00 – Standard General Requirements for Liquid-Immersed Distribution, Power, and Regulating Transformers
  • ANSI C37.13 – Standard for Low Voltage AC Power Circuit Breakers Used in Enclosures
  • ANSI C37.010 – Standard Application Guide for AC High Voltage Circuit Breakers Rated on a Symmetrical Current Basis
  • ANSI C 37.41 – Standard Design Tests for High Voltage Fuses, Distribution Enclosed Single-Pole Air Switches, Fuse Disconnecting Switches and Accessories.
  • NFPA 70 – National Electrical Code, latest edition
  • NFPA 70E – Standard for Electrical Safety in the Workplace, latest edition

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