分布式发电接入电网的静态电压稳定特性及影响分析

Characteristics of static voltage stability for distributed generation integrated into power system and its impacts analysis

分布式发电(Distributed Generation,DG)接入电网在缓解环境污染和能源短缺压力的同时,也会给电网的安全运行分析带来新的挑战,特别是DG控制策略的多样性将使电网静态电压稳定问题更加复杂。DG接入电网对静态电压稳定性的影响主要取决于DG的接入容量、控制方式等因素。首先对DG接入线路的复杂外部网络进行等值,推导负荷节点电压与分布式发电渗透率的解析表达式。在此基础上,分析不同DG渗透率下的节点电压以及负荷PV特性,比较DG采用不同无功控制策略对负荷PV特性的影响。最后,将扩展线路电压稳定指标应用于含DG的电网静态电压稳定分析,研究DG采用主动无功控制策略对线路电压稳定指标的影响。

The integration of distributed generation relieves the pressure of environmental pollution and energy shortage, but at the same time it could bring new challenge to the grid safe operating analysis, particularly the variation of DG control strategies may complicate the static voltage stability analysis. The effect of integrating DG on static voltage stability mostly depends on the capacity and control strategies of DGt Firstly, the equivalent circuit of external grid of DG integrating line is implemented and the analytic expression of load voltage regard to the penetration of DG is derived, and on the basis, the load voltage and the PV characteristic is analyzed under different DG penetrations. Then the impact of the different reactive power control strategies on load PV characteristic is compared. At last, the extended line voltage stability index is used to study the effects of DG reactive power control strategies on the line voltage stability index.