基于PSCAD的特高压直流输电系统建模与仿真分析

Modeling and simulation analysis of UHVDC transmission system based on PSCAD

为了对特高压直流输电系统中的故障变化特性进行准确的仿真与分析,在PSCAD/EMTDC仿真平台上,以宾金直流为例,搭建±800 kV,8000 MW的特高压双极直流输电系统模型,主要对直流输电系统中的无功补偿设备、滤波装置、直流线路、直流控制系统进行详细建模。对于送、受端交流系统,在换流母线处对两侧实际交流系统进行戴维南等值,搭建了以直流系统为主、交流系统简化的实际系统输电模型。并对直流系统的典型故障换相失败进行仿真分析,分析了换相失败故障发生前后,特高压直流系统中主要电气量的变化。通过与实际故障录波的波形进行对比,验证了模型的可行性。着重分析了逆变侧换流母线上流入受端交流系统有功功率、无功功率的变化。研究结论为分析特高压直流换相失败故障对于实际交流系统的影响提供了技术支持。

When studying the interaction between the ultra high-voltage direct current(UHVDC)system and the AC system,the accurate electrical quantity changes of DC fault are important.In order to accurately simulate and analyze the characteristics of fault changes in UHVDC transmission systems,on the PSCAD/EMTDC simulation platform,taking Binkin DC transmission system as an example,a 800 kV,8000 MW bipolar UHVDC transmission system model is built.This model mainly details the reactive power compensation equipment,filtering device,DC line and DC control system in the DC transmission system.For the transmission and reception AC systems,the Thevenin equivalents of the actual AC systems on both sides are made at the converter bus,and a practical system transmission model with a DC system as the main and a simplified AC system is built.The commutation failure of typical faults in the DC system is simulated and analyzed.The main electrical changes in UHVDC system before and after the failure of commutation failure are analyzed.The feasibility of the model is verified by comparing with the waveform of the actual fault recorder.The changes of active power and reactive power flowing into the receiving AC system on the inverter-side converter bus are emphasized.The research conclusion provides technical support for analyzing the impact of UHVDC commutation failure faults on the actual AC system.