State Grid Corporation of China

Taizhou Power Supply Company of State Grid Zhejiang Electric Power

North China Electric Power University

State Grid Zhejiang Electric Power Co., Ltd. Taizhou Power Supply Company

Zaibing Zhou

Zhen Huang

Guode Ying

Tao Zhu

Yuande Zheng

Kang Wang

Hua Xu

Ping Zhao

Jian Wu

Chi Zhang

Hao Tan

Hao Li

Yutao Qiu

Ben Li

Xiaochun Xu

Qingchun Zhao

Xiaotong Zhu

Yiping Shen

Yifan Zhu

Tao Zheng

Chen Zhou

Xu Jiang

Rijun Wang

Chenjing Xu

Fengyuan Wang

Yudong Fang

Zheng Qin

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 ground fault protection method and apparatus for a photovoltaic station output transmission line. A circuit breaker on a photovoltaic side is controlled by a control element. Whether measured zero sequence impedance on the photovoltaic side of a segment line has a large variation before and after an action of power grid side distance protection is determined, the variation of the measured zero sequence impedance is inputted into the control element, in condition that the variation of the measured zero sequence impedance is less than a setting value, a tripping signal is outputted to the circuit breaker on the photovoltaic side to isolate the fault; and in condition that the variation of the measured zero sequence impedance is greater than the setting value, photovoltaic side distance protection is not started.

Ground fault protection method and apparatus for photovoltaic station output transmission line

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

Zaibing Zhou