Simulation And Research On The Transient Process Of Distribute Network Resonant Overvoltage

First,Distribute power network is a net consist of lines,transformers,switches and many other electrical equipments.To detect bus voltage,potential transformers always are linked to the bus.The potential transformer’s primary side always set as Y0 connection.In this kind of system,the capacity between lines and earth,and the inductance in the potential transformer,or in neutral grounding system the inductance in the potential transformer and the capacity from the resonant grounded equipment will build a resonance circuit,which is called L-C circuit.In some cases,resonance can be triggered.such a circuit may leading to overvoltage and overshoot current.causing damages to the electrical equipments.second,In this paper,through the actual operation experience combined with the basic theory of resonance,qualitative analysis of the possible reasons of overvoltage,through extensive understanding of the research status at home and abroad,and then introduces the related theory of ferromagnetic resonance,including its classification and mechanism.starting from the ferromagnetic saturation of the voltage transformer,it is analyzed that the essence of the resonance is that the capacitance energy of the earth is released through the transformer,which leads to over current,thus causing saturation.By analyzing the resonant condition of single phase circuit,the basic condition of resonance is obtained.The paper also describes the structure features of the distribution network and the possible operation conditions of the resonance overvoltage in the actual fault,and summarizes the existing techniques to suppress the ferroresonance and the equipment to eliminate the resonance.Last,This paper also introduces the software ATP-EMTP and the background of the basic theory of related equipment in typical resonant circuit and critical analysis of ferroresonance occurring conditions,formation mechanism and suppression measures and modeling of the resonant oscillation circuit,built ferroresonance overvoltage simplified equivalent circuit model.By changing the different variables,simulation,comparison and analysis of the simulation results of all,put forward the corresponding measures to suppress ferroresonance,and again applied to the simulation model,the conclusion shows that the inhibitory effect of.In addition,the simulation of simplified model,puts forward some methods for improving the simulation model,the simulation through the relevant amount in the actual operation,and compared with the field data,modify the simulation model.In order to build up the simulation model of power distribution network,and based on this,the influence of the existence of multiple lines on the ferroresonance of the whole system is studied,and the practical conclusions are drawn.