一种考虑母线短路容量的电压稳定解析方法

A New Voltage Stability Analysis Method by Considering Short Circuit Capacity

短路容量是系统电压强度的标志。文中提出一种考虑母线短路容量的电压稳定解析方法,揭示了母线短路容量与低压负荷母线电压稳定的解析关系。在对电源侧戴维南等值的基础上,基于配电网的等值负荷模型在不增加系统规模的情况下使电压稳定分析更符合实际。推导得到的保持电压稳定的临界最小短路容量是一个综合性的电压稳定参数,可以直接全面量化配电网负荷侧的变化对电压稳定的影响。比较临界最小短路容量和实际短路容量可以快速评估母线的电压稳定性,跟踪二者的变化可以明确区分造成电压失稳的根本原因,从而为电压稳定控制提供更加明确的参考依据。为母线短路容量应用于广域电压稳定的在线评估和控制提供了强有力的理论支持。

Short circuit capacity is a measure of the robustness of power system voltage. A new method is proposed to use short circuit capacity analyzing voltage stability. The analytical relationship between the short circuit capacity and the voltage stability of the low-voltage load bus is derived. Based on the Thevenin＇ s equivalent for the power source side, the voltage stability analysis with the equivalent load model for the distribution network well matches the actual situation without adding the scale of simulation system. The derived critical minimal short circuit capacity for maintaining voltage stability can directly quantify all the effects on voltage stability due to the changes of the distribution load side, which is a comprehensive voltage stability parameter. By comparing the actual short circuit capacity and the critical minimal short circuit capacity, the voltage stability of the bus could be fast assessed. By tracking the changes of the two capacities, the main reason causing the voltage instability can be determined. Therefore it will provide a clear guide for the voltage stability control. The work is theoretical support for applying short circuit capacity on the on-line assessment and control of wide-area voltage stability.