Operation Analysis and Solution for Mal-operations of Transformer Buchholz Protection in a Transmission Utility
Buchholz relay is one of the main protections for transformer internal fault.But correct operation ratio of Buchholz relays is much lower than transformer differential protection.From 2011 to 2014, more than ten 500kV transformers were tripped by mal-operation of Buchholz relay in China Southern Power Grid (CSG).This paper presents the circumstances when the mal-operations occurred, the findings of the mal-operations and the solutions implemented to avoid the risk of the similar mal-operations.Various solutions including changing output from tripping to alarm, increasing tripping threshold, blocking by high current signal, and adding time delay are analyzed.Adding time delay was chosen as a good and practical solution.It has been implemented on 48 500/220kV transformers, and avoided one mal-trip successfully.
Buchholz relay Mal-operation Transformer protection
Jiang Yu Hongyang Zhou AnWen
国际会议
南京
英文
66-68
2015-09-21（万方平台首次上网日期，不代表论文的发表时间）