融合连续过渡模型与Helmer模型的真空断路器开断模型研究

Interruption Model of Vacuum Circuit Breaker Based on Continuous Transition Model and Helmer Model

真空断路器广泛应用于中压等级电网中,在频繁操作场景下易出现过电压问题,而真空断路器的弧后暂态过程直接决定了其分断特性和过电压特征。为解决现有真空断路器模型难以同时对其弧后过程和高频特性仿真的问题,该文搭建了融合连续过渡模型和Helmer模型的真空断路器开断模型,并通过试验和计算确定其仿真参数。以切除35kV系统用并联电抗器为例,研究该真空断路器融合模型与连续过渡模型和Helmer模型计算结果的差异。结果表明,融合模型能够同时考虑弧后介质恢复过程中重击穿和冷间隙重击穿现象;其弧后参数计算与连续过渡模型基本一致,高频开断特性和Helmer模型较为接近。通过分析高频开断过程中的鞘层生长和重击穿情况,可以得到引起真空断路器高频重击穿的主要原因。该文仿真结果验证了所提出的真空断路器开断模型的准确性,可为真空断路器高频分断条件下的弧后鞘层发展分析和重击穿原因判断提供参考。

Widely used in medium-voltage power grids,the vacuum circuit breaker(VCB)is prone to occur the high-frequency overvoltage in frequent operation scenarios.The post-arc transient process of the VCB directly determines the characteristics of the breaker interruption and the system overvoltage.To solve the problem that the current electromagnetic transient model of VCB is difficult to simulate its post-arc transient process and high-frequency characteristics at the same time,this paper establishes a new model of VCB based on the continuous transition model and the Helmer model and obtains its simulation parameters through tests and calculation.Taking the VCB breaks 35kV system shunt reactors as an example,the difference between the results of the integrated model and those of the continuous transition model and the Helmer model are compared.The results show that the integrated model considers both the restriking process of the cold gap and the dielectric recovery stage.The calculation of the post arc parameters is basically consistent with that of the continuous transition model,and its high frequency breaking characteristics are close to those of the Helmer model.By analyzing the sheath growth and restriking stage,the main reasons for the restrikes of the VCB are obtained.These simulation results verify the feasibility and necessity of the proposed simulation model for the VCB,which provides a reference for the analysis of f sheath growth and the determination of the causes of the restrikes of the VCB under the condition of high-frequency breaking.