Arc Suppression Device Research Articles

A novel method of insulation parameters measurement based on hybrid flexible arc suppression device in distribution networks

As one kind of active arc suppression devices, the hybrid flexible arc suppression device (HFASD) with current-based arc suppression method can eliminate the ground-fault current during the single-line-to-ground (SLG) fault. One of the most important aspects for current-based arc suppression method is the insulation parameters measurement. The reference current of current-based arc suppression method is calculated by the insulation parameters, including the ground capacitance and ground leakage conductance. For the sake of obtaining high-precision reference current of current-based arc suppression method, the insulation parameters should be measured accurately. However, the most of existing methods of insulation parameters measurement should increase the additional device cost and measure inaccurately. In this paper, HFASD based on second-order generalized integrator phase-locked loop (SOGI-PLL) algorithm and twice injection current method is proposed to measure the insulation parameters under the normal condition of distribution networks. The simulation and experimental results verify the effectiveness of the proposed method under different influence factors.

Principle and Control Design of a Novel Hybrid Arc Suppression Device in Distribution Networks

A single line-to-ground (SLG) fault may lead to a more severe line-to-line fault and power supply interruption if the ground-fault current exceeds a certain value. Arc suppression device (ASD) is a good solution to eliminate the ground-fault current. A novel hybrid ASD is proposed in this article, which consists of a passive device and an active one. The passive device utilizes multiterminal breakers and an isolation transformer to couple a secondary voltage of a zig-zag grounding transformer to the neutral point to compensate the majority of the ground-fault current. The active device uses a single-phase voltage source inverter to eliminate the residual fault current due to the leakage inductance of the zig-zag grounding transformer in the passive device. A dual-loop voltage and current control method for the active device is designed for the accurate residual current compensation. Results of simulation and prototype experiment validate the effectiveness of the proposed hybrid ASD. The proposed hybrid ASD does not need to detect distributed line-to-ground parameters, and it has lower cost, less control complexity, higher reliability, and better performance, compared to other ASDs.

Principle of Flexible Ground-Fault Arc Suppression Device Based on Zero-Sequence Voltage Regulation

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.

Research on fault section location method of distribution networks with arc suppression coil grounding based on energy leakage function

In distribution networks with arc suppression coil grounding, the fault line can be set as the energy leakage channel of the capacitive current of the entire system. During the period from fault occurrence to the whole action process of arc suppression coil, there is abundant fault information in the transient waves. However, the data of this period are usually ignored in previous methods. In this study, a novel fault section location method based on the leakage energy function is proposed. Only the fault phase voltage and fault phase current are used in the proposed method, to avoid the difficulty of the zero-sequence current measurement. Then, the action characteristics of two types of arc suppression devices are analysed. The influence of the capacitor current on the fault phase voltage and current during the entire process of arc suppression coil operation is deduced. The difference between the leakage energy on both sides of the fault section is used as the criterion for fault section location. Finally, the effectiveness of the method is verified by a case study. The simulation results indicate that the proposed method has high sensitivity and high impedance adaptability, that will have more advantages in the actual situations.

Single-phase flexible arc suppression device based on BSC-SOGI-PLL method for distribution networks

The single line-to-ground (SLG) fault is a research focus, considering it is amongst the top frequent occurrences of faults in distribution systems. The neutral point treatment is crucial for continuous safe operation of distribution systems. However, the traditional arc suppression coil cannot compensate for the active component in ground current. Therefore, we present a single-phase flexible arc suppression device (SFASD) based on backstepping control and second-order generalized integrator phase-locked loop (BSC-SOGI-PLL) method. The SFASD with a cascaded H-bridge (CHB) topology is connected to the neutral point of distribution systems for eliminating the ground current. The comparisons between the BSC-SOGI-PLL and the BSC method concerning the effect of arc suppression are discussed. The effectiveness of the proposed SFASD based on the BSC-SOGI-PLL components for arc suppression is verified on the scale-down experimental platform.

Two-Phase Current Injection Method for Single Line-to-Ground Fault Arc-Suppression With Revised STATCOM

To suppress the arc current in the single line-to-ground (SLG) fault in neutral isolated distribution network, a two-phase current injection method is proposed for the revised static synchronous compensator (STATCOM), as an extra function during the SLG fault. Therefore, the traditional roles of the dedicated passive coil or power electronic based arc-suppression devices can be taken by this multi-purpose STATCOM. This article first introduces the principles and the models of the arc-suppression current injection during SLG fault. Then, different options of arc-suppression current injection by the revised STATCOM are analyzed in terms of stabilizing the floating dc capacitor voltages of the cascaded H-bridges (CHB) converter. It is discovered that the two-phase current injection is the only viable option to maintain the floating dc capacitors voltages. Then, the arc-suppression current controller and the dc capacitors voltages controller are proposed, and the design process of the control parameters adapting to the varying transitional (grounding) resistances computed online is also introduced. The proposed methods are first validated by simulations. Then, an MVA-rating CHB converter prototype is constructed, and 10 kV feeder SLG fault and arc-suppression experiments are performed to demonstrate the effectiveness of the proposed method.

FASD based on BSC method for distribution networks

A Petersen coil was used as a passive arc-suppression device (ASD) to mitigate ground-fault current when a single-phase-to-ground fault occurred in distribution networks. However, passive ASDs cannot compensate for the active and harmonic components of ground-fault current. Furthermore, a massive residual ground-fault current would endanger human life and the reliable operation of distribution networks. To overcome the shortcomings of passive ASDs, a three-phase flexible ASD (FASD) with a three-phase cascaded H-bridge topology was presented. A three-phase FASD connected to a bus bar of distribution networks was employed to compensate for the ground-fault current. In this study, the FASD with the backstepping control (BSC) based on current-compensation principle was proposed to completely eliminate the ground-fault current. The effectiveness of the proposed FASD with the BSC method was verified using the simulation and experimental results.

Flexible arc-suppression method based on improved distributed commutations modulation for distribution networks

Because of the hazard of single-phase-to-ground faults on distribution networks for human security and device insulation, it is important for the ground-fault current to be eliminated by an arc-suppression device. However, owing to their shortcomings, passive arc-suppression devices cannot compensate the ground-fault current fully. Therefore, active arc-suppression devices have been studied. The flexible arc-suppression device (FASD) with a cascaded H-bridge (HB) topology is one type of active arc-suppression device. An FASD connected to a bus bar of distribution networks is applied to mitigate the ground-fault current. Owing to the high voltage and large current during the ground fault, a large number of HBs are required for the FASD. To modulate the HBs, an improved distributed commutations modulation method, which is combined with the flexible arc-suppression method, is proposed. The proposed modulation strategy aims to minimise the error between the reference signal and the tracking signal during each sampling period. Finally, the proposed strategy is validated via simulations and experiments to confirm its effectiveness for the FASD.

Model-Predictive-Control-Based Flexible Arc-Suppression Method for Earth Fault in Distribution Networks

Traditional arc-suppression devices have a weak effect on the arc-extinguishing result of earth fault because of increased active and harmonic components of fault current. To solve the problem, in this paper, a flexible arc-suppression device based on a three-phase cascaded H-bridge (CHB) converter with auxiliary sources is further developed; on this basis, an arc-suppression method based on the improved finite control set model predictive control is proposed. The proposed approach, which uses a combination of two voltage levels in a sampling period to reduce the steady-state current error, controls the CHB converter to inject compensation current into the distribution network. Taking into account the reduction of switching losses and balancing heat in each H-bridge cell, a novel method that causes the switching transitions to be distributed evenly among the H-bridge cells is proposed to select the optimal switching combination. The tracking capability of the improved control method is analyzed, and the parameters affecting the arc-suppression performance are obtained. The simulation and experimental results show that the proposed method achieves an excellent performance of suppressing fault current and extinguishing arc. Moreover, the balance of switching transitions is also achieved.

Principle and Control Design of Active Ground-Fault Arc Suppression Device for Full Compensation of Ground Current

Traditional ground-fault arc suppression devices mainly deal with capacitive component of ground current and have weak effect on the active and harmonic ones, which limits the arc suppression performance. The capacitive-current detection needed in them suffers from low accuracy and robustness. The commonly used large-capacity reactive component may bring about overvoltage because of possible resonance with the distributed phase-to-ground capacitance. To solve these problems, an active ground-fault arc suppression device is presented. It employs a topology based on a single-phase inverter to inject current into the neutral without any large-capacity reactors, and, thus, avoids the aforementioned overvoltage. It compensates all the active, reactive, and harmonic components of the ground current to reliably extinguish the ground-fault arcs. A dual-loop voltage control method is proposed to realize arc suppression without capacitive-current detection. Its time-based feature also brings the benefit of fast response on ground-fault arc suppression. The principle of full current compensation is analyzed, together with the controller design method of the proposed device. Experiment on a prototype was carried out to validate the effectiveness of the device.