背靠背直流输电的交流电网故障计算模型研究

Research on Fault Calculation Model for AC Power Grid with Back-to-back HVDC Transmission

背靠背直流输电系统由于两侧换流器联系紧密,在一侧交流电网发生故障时会对另一侧交流系统造成影响。现有的故障计算模型并不适用于背靠背直流,为此,在计及直流系统控制特性的换流器等值模型基础上,分析了背靠背直流系统中谐波传变特性和两侧交流电网间的故障影响机理,并建立了背靠背直流系统故障计算模型;利用该模型结合双端交流电网网络结构以及故障侧的边界条件,提出一种含背靠背直流输电的电网故障分析方法。将所提出的故障计算模型应用于灵宝背靠背直流输电模型的故障分析计算,并与PSCAD/EMTDC软件仿真结果相比较,结果表明所提模型和方法是有效的。

Due to close relation of both sides converters of the back- to-back （BTB） HVDC pat one side of the AC power grid will cause impact on another side of the AC synot suitable for BTB HVDC, therefore, on the basis of equivalent model of the converter counting control characteristics of the DC system, this paper analyzes harmonic interaction characteristic in the DC system and fault influencing mechanism be-tween the connected AC systems and establishes a fault calculation model for the BTB HVDC system. Combining grid struc-tures of the double-ended AC power grids and boundary conditions at the fault side, it presents a kind of fault analysis meth-od for the power grid with BTB HVDC power transmission. The proposed fault calculation model was applied in fault analy-sis and calculation for Lingbao BTB HVDC power transmission model and related results were compared with those from PSCAD/EMTDC simulation. It proves effectiveness of the proposed model and method.