What This Document Is
This is a homework assignment for ECE 525: Power System Protection and Relaying, offered at the University of Idaho. It focuses on the practical application of power system protection principles to a specific network scenario. Students are tasked with designing and coordinating protective schemes for a multi-section power system, including transformers and distribution feeders. This assignment requires a detailed understanding of relay settings, coordination time intervals, and fault current calculations.
Why This Document Matters
This assignment is crucial for students seeking to solidify their understanding of power system protection. It’s designed for those actively learning about relaying techniques and preparing to apply them in real-world engineering scenarios. Successfully completing this assignment will demonstrate proficiency in protective device coordination, a core skill for power engineers. It’s best utilized after covering the fundamentals of fault analysis, relay characteristics, and coordination principles in lectures and readings.
Topics Covered
* Protective Relay Settings (Phase & Ground)
* Time Overcurrent (TOC) Curve Selection
* Coordination of Protective Devices (Relays & Reclosers)
* Fault Current Calculations (Phase-to-Phase, Three-Phase, Single Line-to-Ground)
* Transformer Protection
* Current Transformer (CTR) Selection
* Impact of Zero Sequence Imbalance on Fault Currents
* Application of ANSI/IEEE Standard Damage Curves
What This Document Provides
* A detailed power system network diagram with specified impedances and load characteristics.
* Fault current data for various fault locations and types, enabling coordination studies.
* A selection of inverse time overcurrent curves for consideration in relay setting calculations.
* A transformer damage curve to guide protective device coordination and prevent equipment failure.
* Specific assumptions and constraints to guide the coordination process, such as coordinating time intervals and transformer phase shift characteristics.