Modeling and simulation of power system protection relays in a transmission-level application

This report presents the findings of an in-depth literature review on protective relaying. The project focuses on protection system practices which are relevant to transmission-level applications. Various implementations of differential, phase distance and ground distance relays were investigated and ultimately modeled in the Matlab Simulink environment. A further model for a saturable iron-core current transformer was also investigated and developed. These models were tested to ensure compliance with expected results. The developed relay and current transformer models are used to complete a detailed protection design for a sample power system. A small 230kV bulk-power transmission system is presented and modeled in the Simulink environment. A fault study is completed and current transformers are specified in accordance with IEEE standards. Bus and line protections are selected from the various implementations discussed in the report. The settings for all protection relays are developed in detail based on system analysis and the expert guidelines obtained from a wide literature review. The resulting protection design was tested in a systematic fashion and demonstrated to be effective.