Active arc suppression device based on voltage‐source convertor with consideration of line impedance in distribution networks

Abstract

In the non‐effectively grounding distribution system, residual current under single‐line‐to‐ground (SLG) fault threatens the safety of human being and power supply equipment. Active arc suppression device has been proved to be effective for SLG fault arc suppression when the line impedance is ignored. However, in practice, line impedance varies with the fault location and the load current flowing through the impedance brings about additional voltage drop, which increases the fault current and is not dealt with by the conventional methods. To achieve accurate SLG fault arc suppression with the existence of line impedance, the neutral‐to‐ground voltage reference for full ground‐fault current compensation is firstly derived and a detection method is then proposed. The pre‐fault and post‐fault line currents are used to eliminate the influence of load current on the line impedance voltage drop. A dual‐loop voltage and current controller is then designed. The prototype of active arc suppression device was developed. The results of simulation and prototype experiment validate the effectiveness of the proposed method.

Novel arc suppression method for single-phase grounding fault considering line voltage drop

“…In order to extinguish the fault arc reliably, the influence of the line voltage drop can't be ignored, so the reference value of the neutral point voltage needs to be revised. When the neutral point voltage is regulated according to (13), the fault point voltage can be suppressed to zero, and the fault current at this time is correspondingly reduced to zero.…”

“…In addition, considering the existence of phase-to-phase capacitance and phase-to-ground capacitance, mA I & and mA0 I & will change along the line, so the average value of the current between the bus and the fault point is selected when using (13) to calculate the neutral point reference voltage. The average value of mA I & can be obtained by subtracting the average value of the phase-to-phase capacitive current from the measured value at the beginning of the fault line.…”

“…According to the different control objectives, active arc suppression methods can be divided into active current-type arc suppression methods (ACAS) and active voltage-type arc suppression methods (AVAS) [13]. The ACAS obtains 2 the injection current according to the distribution network parameters, it has good performance in low resistance fault and is not affected by line impedance and load current.…”

A Novel Fault Current Full Compensation Method in Active Flexible Grounding Distribution Networks

“…At present, the control technology mainly uses the integration of proportional-integral (PI) control and proportional-resonant (PR) control or double closed-loop to realize flexible control of power electronic equipment. The fast response speed of PI control [5] and the precise control of PR control [6] to specific frequency are the important reasons for the wide application of these two control methods in the control of power electronic equipment.…”