适用于柔性直流电网操作过电压分析的混合式高压直流断路器端口等效模型

Port Equivalent Model of Hybrid High Voltage DC Breaker for Switching Overvoltage Simulation in VSC-HVDC Grids

柔性直流电网中混合式高压直流断路器动作时会产生较大的操作过电压,但是目前尚缺乏针对直流断路器操作过电压仿真模型的研究。针对主流的混合式高压直流断路器,提出了用于柔性直流电网操作过电压仿真的断路器端口等效模型,同时介绍了该模型中各参数的计算方法。该模型的一个突出优点是,建模时仅需要知道一些原始设计指标和个别组件的动作时间,不涉及断路器内部结构与参数,减小了工程设计阶段断路器建模的难度。在实验室开展了断路器的短路电流分断试验,并利用提出方法建立了试验断路器的仿真模型,试验结果与仿真结果对比显示:该建模方法在仿真直流断路器操作过电压时具有较高的仿真精度,过电压峰值误差最大仅为3.1%。最后,通过张北工程的仿真模型验证了该模型在电网中也具有较高的仿真精度,多次仿真中过电压峰值误差最大仅为3.3%。

A high switching overvoltage will occur when hybrid high voltage DC breaker(H-HVDCB)operates in voltage-source-converter-based high voltage direct current(VSC-HVDC)grids.At present,there is no research on the simulation model of H-HVDCB for switching overvoltage simulation.Aiming at the mainstream H-HVDCB,we put forward a port equivalent model of H-HVDCB for switching overvoltage simulation in VSC-HVDC grids.The calculation method of the parameters in the model is also introduced.A significant advantage of this model is that it only needs to know some original design indicators and the action time of some individual components when modeling,and does not involve the internal structure and parameters of the H-HVDCB,which reduces the difficulty of modeling during the engineering design phase.The breaking test of the H-HVDCB is carried out in the laboratory.Meanwhile,the simulation model of the test H-HVDCB is established by using the proposed method.The comparison between the experimental results and simulation results shows that the proposed model has high simulation accuracy when simulating the overvoltage of H-HVDCB.The maximum error of the peak voltage during the test is only 3.1%.Finally,the simulation model of Zhangbei project verifies that the proposed model also has high simulation accuracy in power grids.The maximum error of the peak voltage is only 3.3%in multiple simulations.