State Grid Corporation of China

Taizhou Power Supply Company of State Grid Zhejiang Electric Power

Qingchun Zhao

Zhen Huang

Jian Wu

Guode Ying

Tao Zhu

Kang Wang

Hua Xu

Yuande Zheng

Hao Tan

Ping Zhao

Zaibing Zhou

Hao Li

Ben Li

Xiaochun Xu

Xiaotong Zhu

Yiping Shen

Yutao Qiu

Chi Zhang

Chen Zhou

Xu Jiang

Zheng Qin

Rijun Wang

Provided is a determination method of differential protection suitable for an electricity transmission line with multi-terminal T-connection. The determination method includes: sampling and calculating all phase currents, and calculating a maximum fault component current &#x394;&#x130;in phase current amplitudes of each phase current, a differential current Iin the each phase current, a resistive current Iin the each phase current and a vector sum &#x394;&#x130;of fault component currents except &#x394;&#x130;in the phase current amplitudes of the each phase current; and comparing the maximum fault component current &#x394;&#x130;in phase current amplitudes of each phase current and a threshold setting value I, determining a value of a resistive coefficient K corresponding to the phase current amplitudes of the each phase current according to a comparison result, and performing differential determination on the differential current Iand the resistive current Iin phase current amplitudes of the each phase current according to a differential determination formula: if the differential current Iof the target phase satisfies the above differential determination formula, it is determined that a fault occurs in an area of the target phase.

Differential protection determination method

Provided are a differential protection method and system, applied to a multi-terminal T-connection transmission line. The method includes: selecting two slaves without a connection and connecting the two slaves to construct a slave group; determining a target slave and an auxiliary slave in the slave group, where a first communication path is connected along a channel one, a channel two and a channel three, and a second communication path is connected along the channel three, the channel two and the channel one; transmitting, by the target slave, two frames of messages, and acquiring a delay difference between a transceiving delay of the first communication path and a transceiving delay of the second communication path, where a first frame of messages is transmitted to the target slave via the first communication path, a second frame of messages is transmitted to the target slave via the second communication path.

Differential protection method and system

Growing community of inventors

Zhejiang, China

Qingchun Zhao