Research On Optimization Of Arc-Suppression Methods For Arc Grounding Faults In Distribution Networks Based On Active Transfer Arc-Suppression Technology

The distribution network has a wide distribution area,and the operating environment is complex and changeable.It is prone to arc ground faults.The arc fault current is small and has complex evolution characteristics such as transient and intermittent.It is difficult to identify and suppress faults.On the other hand,long-term operation with faults or grounding faults that are not eliminated in time can easily cause faults to spread and large-scale blackouts,which endanger the reliable and stable operation of the power grid.In recent years,the voltage-based arc suppression method has become a new development direction,and the active transfer arc suppression technology based on fault phase grounding has been gradually promoted.First,the active transfer arc suppression technology needs to accurately identify the fault phase.Second,when the voltage drop of the distribution line cannot be ignored,there is a lack of analysis and demonstration of the arc suppression capability of the voltage arc suppression method.In response to the above problems,this paper has done the following work:The active transfer arc suppression technology uses the fault phase grounding at the busbar to realize the voltage regulation of the fault phase,so the accurate identification of the fault phase is the basis of its reliable arc extinguishing.Since the arc ignition and arc extinguishing moments are uncertain,this brings certain difficulties to the fault phase selection criterion based on steady-state characteristics.This paper analyzes the three-phase voltage transient signal after the fault and obtains the fault phase transient voltage waveform and non-The polarity of the fault phase is opposite,and a method is proposed to judge the fault phase by using the similarity of the transient voltage waveforms of the fault phase and the non-fault phase;Matlab&Simulink is used to establish a 10 k V typical distribution network model and an arc fault model,and grounding at different neutral points The arc grounding fault conditions such as transition resistance,fault point distance,fault phase angle,intermittent grounding,etc.are changed to verify the fault phase identification method.The simulation results show that the proposed fault phase identification methods can correctly select single-phase grounding faults under different transition resistance,fault distance and intermittent arc fault conditions.In this paper,considering the influence of the line voltage drop,the current expression of the fault point before and after the active transfer device is put into use is deduced;the influence law of the transition resistance,fault distance and load current on the fault point current is further analyzed,and the above is verified by simulation.The influence of factors on the current at the fault point.Then,in view of the problem that the active intervention of arc suppression technology may increase the current at the fault point when the fault distance is long and the load current is large,the distribution network model and the arc model under the unfavorable conditions of long feeder and heavy load are established for different transition resistances.The effectiveness of the arc extinguishing at the time is verified.The simulation shows that:considering the breakdown voltage of the arc discharge gap,the fault transfer device can effectively extinguish the arc in the case of a low resistance fault;at the same time,the active transfer arc extinguishing device is simulated for the harmonic component transfer ability,which can effectively transfer the harmonic component and realize Reliable arc extinguishing due to ground fault.