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Abstract With the rapid development of social economy, power supply reliability of the distribution network has become particularly important. The distribution network has long been faced with problems such as overvoltage, single‐phase grounding failure and grounding protection. Passive, active, and hybrid arc suppression devices (ASDs) are proposed to solve these problems. Passive ASDs have the advantages of high reliability, low control complexity and good economic benefits, and have been widely used in distribution networks. With the wide application of power electronic components in distribution network, the active part and harmonic part of ground current, which cannot be effectively eliminated by passive ASDs, increase sharply. Therefore, an active arc suppression method is proposed. However, due to the high cost and low reliability of the active equipment, the hybrid ASD has better arc suppression effect. In this paper, the existing ASDs are reviewed, and specific simulation models are established to verify the principle and performance of three different ASDs. The advantages and disadvantages of the three ASDs are compared in detail, and the possible problems and research directions in the future research of arc suppression technology are prospected.

In the neutral ungrounded distribution network, the removal of permanent single-line-to-ground (SLG) fault easily leads to saturation of the electromagnetic voltage transformers (PT), which may cause ferroresonance overvoltage and PT failure. This paper analyzes the zero-sequence voltage after the removal of the SLG fault and reveals the mechanism of ferroresonance excited by the removal of the SLG fault. Then, the total power and transient energy of the zero-sequence circuit under the SLG fault are analyzed. It is deduced that the energy reaches the minimum value at the zero-cross point (ZCP) of the neutral voltage. Based on this, a permanent SLG fault removal method to avoid ferroresonance is proposed, which uses the ZCP point as the fault removal instant. Simulations in ATP-EMTP show that the proposed method can effectively avoid ferroresonance on subharmonic mode. It can also enhance the ferroresonance suppression performance of the ferroresonance suppression resistor in the fundamental-frequency and high-frequency conditions.

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.

Single-line-to-ground (SLG) fault arcs cause the intermittent over-voltages, leading to short circuits within large-scale area. In this paper, a flexible arc suppression device is proposed, which adopts a zigzag grounding transformer, multi-terminal breakers and an isolation transformer to regulate zero-sequence voltage. Principle of zero-sequence voltage regulation (ZVR) and arc suppression method is presented. By carefully choosing the secondary side voltages of grounding transformer as the input of isolation transformer, the zero-sequence voltage is nearly constrained to the opposite of faulty phase supply voltage, and the ground-fault current is limited to a very small value. This device has high adaptability for low-resistance ground fault as it doesn't adopt any electronic apparatus. A 10kV prototype was established and multiple fault conditions were experimented to verify the effectiveness of the proposed ZVR device and its arc suppression principle.