Tsinghua University

Alstom Technology Limited

Alstom Grid UK Limited

Areva T&d UK Limited

Schneider Electric Energy UK Ltd.

Xinzhou Dong

Tao Cui

Andrzej Klimek

Haonan Wang

Xuyang Li

Zhiqian Bo

Ray Chatfield

Boliang Jin

Shenxing Shi

Qilong Qian

Andrzej Juszczyk

The present invention discloses A method of single-phase-to-ground fault line selection for a distribution line based on the comparison of phase current traveling waves, comprising: sampling three phases current traveling waves on the distribution line, and taking the busbar pointing to the line as the current positive direction; when a single-phase-to-ground fault occurs on the distribution lines, comparing the amplitude and polarity of the difference between the three phases current traveling waves before and after the fault, wherein when the amplitude of one of the three phases current traveling wave is higher than 1.5 times of the amplitude of the other two phases current traveling waves, and the polarity of the one of three phases current traveling wave of the largest amplitude is opposite to the polarity of the other two phases current traveling waves, it is determined that the fault occurs on the load side of the measuring point of the line, and the phase with the largest amplitude of the current traveling wave is the fault phase; if the difference of the amplitudes of the three phases current traveling waves is within a predetermined value and the polarity is the same, it is determined that the fault occurs on the power source side of the measuring point of the line. By the technical solution of The present invention, the precise line selection of the single-phase ground fault of the distribution line can be realized.

Single-phase-to-ground fault line selection method for distribution lines and computer readable storage medium

The present disclosure proposes a power flow analysis device and a power flow analysis method for an AC/DC hybrid system. Wherein, the device comprises: a memory being stored a computer program; and a processor performing the following steps when executing the computer program: obtaining an AC system voltage and a commutation reaction of the DC transmission system, a first trigger angle of the rectifier, and a second trigger angle of the inverter; constructing an AC equivalent model according to the AC system voltage, the commutation reaction, the first trigger angle, and the second trigger angle; and performing a power flow calculation according to the AC equivalent model to obtain a power flow analysis result of the AC/DC hybrid system. Therefore, the power flow analysis and calculation problem of the AC/DC hybrid system is transformed into the power flow analysis and calculation problem of the pure AC system, which overcomes the problem that the DC system variables are not easily decoupled in the power flow analysis and calculation, and takes into account the efficiency and accuracy of the power flow calculation.

Power flow analysis device and power flow analysis method for AC/DC hybrid system

The invention concerns a method and a system for online ferroresonance detection in a high voltage electrical distribution network. The method includes:

Method and system for online ferroresonance detection

The method for detecting single-phase grounding fault based on the harmonic component of residual current is provided, in which collecting and calculating the phase differences of third harmonic waves relative to the fundamental wave of the residual current in the feeder line, and judging if the phase differences of the residual current in the feeder line is into a threshold range, and judging if there is a suspected grounding fault, and confirming the fault event by judging the duration and the generated times of the suspected grounding fault. Another method for detecting single-phase grounding fault based on the harmonic component of residual current is provided, in which the residual current of neutral point is used.

Method for detecting single phase grounding fault based on harmonic component of residual current

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Beijing, China

Xinzhou Dong