Estimating zero-sequence impedance of three-terminal transmission line and Thevenin impedance using relay measurement data  

作　　者：Swagata Das Sundaravaradan Navalpakkam Ananthan Surya Santoso 

机构地区：[1]Schweitzer Engineering Laboratories,Pullman,USA [2]Department of Electrical and Computer Engineering,The University of Texas,Austin,USA

出　　处：《Protection and Control of Modern Power Systems》2018年第1期382-391,共10页现代电力系统保护与控制（英文）

摘　　要：Current and voltage waveforms recorded by intelligent electronic devices(IEDs)are more useful than just performing post-fault analysis.The objective of this paper is to present techniques to estimate the zero-sequence line impedance of all sections of a three-terminal line and the Thevenin equivalent impedance of the transmission network upstream from the monitoring location using protective relay data collected during short-circuit ground fault events.Protective relaying data from all three terminals may not be always available.Furthermore,the data from each terminal may be unsynchronized and collected at different sampling rates with dissimilar fault time instants.Hence,this paper presents approaches which use unsynchronized measurement data from all the terminals as well as data from only two terminals to estimate the zero-sequence line impedance of all the sections of a three-terminal line.An algorithm to calculate positive-,negative-and zero-sequence Thevenin impedance of the upstream transmission network has also been presented in this paper.The efficacy of the proposed algorithms are demonstrated using a test case.The magnitude error percentage in determining the zero-sequence impedance was less than 1%in the test case presented.

关 键 词：Zero-sequence Three-terminal line Thevenin Impedance 

分 类 号：TN9[电子电信—信息与通信工程]