【Title】An Improved Scheme of Transformer's Zero-sequence Over-current Protection With Internal Bridge Connection
【Abstract】Briefly describes the bridge connection of transformer zero sequence over current protection the traditional criteria, namely, the line TA self-produced zero current and Bridge TA self-produced zero flow vector and in zero sequence overcurrent protection logic operation. The sequence component method are analyzed in bridge connection mode of three kinds of common mode transformer, single phase to ground fault, the relationship of flows through the TA line of zero sequence current and Bridge TA the size of zero sequence current and amplitude with Two vector sum. The research shows that the sensitivity of the conventional zero sequence overcurrent protection can be reduced when the single phase to ground fault in the three operating modes is studied. The TA line self-produced zero flow, bridge TA self-produced zero flow and vector sum composition or gate criterion is applied to zero sequence overcurrent protection was put forward. Through checking, the criterion in the transformer earthing fault action and original criterion consistent, but external connected fault zero sequence over flow protection sensitivity will effectively improve to meet the sensitivity of relay protection requirements. Finally, the correctness of the scheme is verified by RTDS simulation, and the scheme is extended to all kinds of voltage levels, and the zero sequence overcurrent protection.
【Keywords】Low voltage side differential protection; Split phase differential protection; phase-to-phase fault【作者】
|FENG Guo-dong||: Shanghai SHR Automation Co.Ltd.,Shanghai 201108,China;|
【出版时间】Tue Nov 15 00:00:00 CST 2016
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