Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The invention concerns a method and a system for online ferroresonance detection in a high voltage electrical distribution network. The method includes: Overflux detection (23), which acts as the start element, overflux being set if the flux is greater than a threshold for specified time duration, mode verification (26) which is to recognize the modes of the ferroresonance, a fuzzy logic method being used to discriminate the ferroresonance modes.

Abstract: 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.

Abstract: The invention concerns a method and a system for online ferroresonance detection in a high voltage electrical distribution network. The method includes: Overflux detection (23), which acts as the start element, overflux being set if the flux is greater than a threshold for specified time duration, mode verification (26) which is to recognize the modes of the ferroresonance, a fuzzy logic method being used to discriminate the ferroresonance modes.

Abstract: A method and a system for transient and intermittent earth fault detection and direction determination in a three-phase median voltage electric power distribution system which comprises many lines. The system comprises: sampling means wherein the residual current and residual voltage on said lines are sampled, transient direction detection means based on instantaneous power, random intermittent detection means based on intermittent change of residual current amplitude, means of integrating transient direction and random intermittent detection, and alarm means indicating maintenance personnel to check the status of one line.

Abstract: 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.