一种快速估算运行状态母线短路容量的方法

A Method for Fast Calculation of Operating Bus Short-circuit Capacity

实时估算运行状态下的母线短路容量,对于评估系统在各种扰动工况下的稳定水平以及继电保护整定计算具有十分重要的实践价值。针对不同运行方式下母线的实时短路容量不易获取的问题,运用戴维南定理对母线的系统侧进行端口等效,并依据负荷工况的变化对母线电压功角影响的条件,推导出功率变化量、电压变化率与母线短路容量之间关系。由于功率变化量和电压变化率便于直接测量,依据上述三者之间的关系,就能方便地估算出母线短路容量。

Estimating short circuit capacity of bus is important for evaluating system robustness and is essence to setting and coordinating relaying protections. The short circuit capacity calculation for operating bus is not convenient. In this paper, the Thevenin＇s theory is applied to construct a two-port network for operating bus with different loading conditions. Then, the relationships among power increment, voltage regulation and short circuit capacity is obtained. Considering power increment and voltage change rate are easy to measure, the short circuit capacity calculation for operating bus can be obtained.