An Algorithmic Approach for Identifying Critical Distance Relays for Transient Stability Studies

Ramin Vakili,Philip Augustin,Vijay Vittal,Mojdeh Khorsand,Bill Robertson

doi:10.1109/oajpe.2021.3064514

Ramin Vakili, Philip Augustin + Show 3 more

Open Access

https://doi.org/10.1109/oajpe.2021.3064514

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Abstract

After major disturbances, power system behavior is governed by the dynamic characteristics of its assets and protection schemes. Therefore, modeling protection devices is essential for performing accurate stability studies. Modeling all the protection devices in a bulk power system is an intractable task due to the limitations of current stability software, and the difficulty in updating the setting data for thousands of protection devices. One of the critical protection schemes that is not adequately modeled in stability studies is distance relaying. Therefore, this paper proposes an iterative algorithm that uses two methods to identify the critical distance relays to be modeled in stability studies: (i) apparent impedance monitoring, and (ii) the minimum voltage evaluation (MVE). The algorithm is implemented in Python 3.6 and uses the GE positive sequence load flow analysis (PSLF) software for performing stability studies. The performance of the algorithm is evaluated on the Western Electricity Coordinating Council (WECC) system data representing the 2018 summer-peak load. The results of the case studies representing various types of contingencies show that to have an accurate assessment of system behavior, modeling the critical distance relays identified by the algorithm suffices, and there is no need for modeling all the distance relays.

Highlights

T HE North American Electric Reliability Corporation (NERC) has identified protection systems as critical reliability assets in modern power grids [1] that play a crucial role in defining the system behavior during and after disturbances
This paper proposes an algorithm for identifying the critical distance relays that are essential to be modeled for performing accurate transient stability studies of different types of contingencies
The Western Electricity Coordinating Council (WECC) system data is used as the test system and different contingencies including line faults and bus faults were studied to evaluate the performance of the proposed algorithm

Summary

INTRODUCTION

T HE North American Electric Reliability Corporation (NERC) has identified protection systems as critical reliability assets in modern power grids [1] that play a crucial role in defining the system behavior during and after disturbances. It is essential that any algorithm developed for identifying the critical distance relays be capable of identifying these distance relay misoperations occurring at distant locations as well Such an algorithm enables a more realistic assessment of power system behavior while using transient stability analysis software, including the CAPE-TS co-simulation platform. An iterative algorithm is proposed in this paper that uses two methods of apparent impedance monitoring and the MVE to identify the critical distance relays that are required to be modeled in the stability studies of different contingencies. Unlike previous methods, the proposed algorithm can identify these distance relays as critical and model them in transient stability studies, which enables a precise assessment of the dynamic behavior of the systems with a high penetration level of renewable resources.

IDENTIFICATION OF CRITICAL DISTANCE RELAYS

Objective

CASE STUDIES

Findings

CONCLUSION