Simulation Research On Arc Characteristics Of DC Vacuum Circuit Breaker Based On Field Fine Analysis

Vacuum circuit breakers(VCBs)are widely used in medium voltage power system for their advantages of medium friendly environment,maintenance-free,miniaturization.As the control and protection device in multi-terminal DC transmission,distribution and power system,the insulation and arc characteristics of DC vacuum interruption(?)directly affect the whole operation performance.Mechanical type DC VCB inevitably generate arc during the breaking process.Studying the characteristics of interruption of vacuum arc and its control measures is the key to improve the dielectric recovery performance and the life cycle operation performance of the VCB.In this dissertation,15kV/630A/10kA single-break mechanical type DC VCB is taken as the research object.On the basis of the topological structure design and optimization of the converter circuit of the VCB.The electric and magnetic field of the DC VI is modeled and analyzed.Fine simulation of insulation and magnetic field characteristics have been realized for analyzing the insulation and dielectric recovery performance of the VCBs.Based on the commutation topology of 15kV/630A/10kA single-break mechanical DC VCB,the parameters of the commutation circuit topology components are numerically calculated.And the genetic algorithm and variable step-size fourth-order Runge-Kutta method are used.The optimal commutation circuit parameters considering the main circuit parameters and transient recovery voltage(TRV)are obtained.Aiming at the requirements for insulation and breaking capacity of single-break DC VCB,the axisymmetric electric field three-dimensional magnetic field model are established.Considering the optimized commutation circuit parameters,dynamic changes of main circuit current and TRV are taken as field-circuit coupling excitation of the DC VCB.And finite element method is applied to numerically simulate the electromagnetic field of the VI.According to the typical prototype experimental platform of the mechanical type DC VCB,the dynamic changes of arc current,voltage,energy,power and break region resistance are obtained by sampling the current and voltage waveforms during the breaking for quantitatively describing the temperature distribution of the metal vapor arc region.