考虑抑制MIDC后续换相失败风险的节点差异化动态无功补偿方法研究

多馈入直流系统(multi-infeed direct current,MIDC)多回直流间电气联系紧密,交流侧故障导致的换相失败若无干预极易引发后续连锁反应直至直流闭锁,严重毁坏系统安全稳定。动态无功补偿装置可在电压跌落瞬间为换流母线提供有效支撑,抑制直流后续换相失败风险,但由于配置成本较高,大规模应用仍较为困难。为合理降低动态无功补偿配置成本,提高配置方案的经济性和实用性,提出一种考虑抑制MIDC后续换相失败风险的节点差异化动态无功补偿方法。首先对后续换相失败发生机理进行分析,提出一种抑制后续换相失败风险效果的评价指标;根据节点特性对候选补偿节点进行了换相失败关联度的评估和预分区;建立了抑制后续换相失败风险的节点差异化动态无功补偿装置配置模型,利用基于精英改进策略的“教与学”优化(teaching-learning-based optimization,TLBO)算法求解该模型,得到了灵活考虑经济效益与无功补偿效果的动态无功补偿装置差异化配置方案;最后在PSD-BPA和MATLAB联合仿真平台上,用华东电网实际算例验证了所提方法的合理性与有效性。

Node Differential Dynamic Reactive Power Compensation Considering Risk Restraints of Subsequent Commutation Failure of MIDC

A multi-infeed direct current(MIDC)system has close electrical connections between the multiple DC circuits.If there is no intervention,the commutation failure caused by an AC side fault will easily lead to subsequent chain reactions,or even a DC blocking,which will seriously ruin the safety and stability of the system.A dynamic reactive power compensation device may provide an effective support for the converter bus at the moment of a voltage drop,suppressing the risk of subsequent commutation failure.However,due to the high configuration costs,its large scale application is still hard to realize.In order to reduce the configuration costs of the dynamic reactive power compensation reasonably and improve the economy and practicability of the configuration scheme,a node differential dynamic reactive power compensation method considering the risk of subsequent commutation failure of the MIDC is proposed.This paper firstly analyses the mechanism of subsequent commutation failures,and proposes an evaluation index for restraining the risk of the subsequent commutation failure.According to the characteristics of the nodes,the node commutation failure relevancy of the candidate compensation nodes are evaluated and pre-partitioned.Then,the node differentiated dynamic reactive power compensation device configuration model is established for suppressing the risk of the subsequent commutation failure,and the improved TLBO algorithm is used to solve the model,obtaining a dynamic reactive power compensation device differential configuration scheme which flexibly considers the economic benefits and the reactive power compensation effects.Finally,the actual example of East China Power Grid on the co-simulation platform with the PSD-BPA and the MATLAB verifies the rationality and effectiveness of the proposed method.