多根情報による重負荷時電圧崩壊可能母線の検出に関する考察

抄録

Conventionally, most of voltage stability indices, including Voltage Stability Proximity Index (VIPI), have been formulated for the overall system. Voltage instability phenomena, however, can occur locally and then cause cascade collapses throughout the system. Therefore, it is of significant importance to establish an index that can locate the possible voltage collapse buses in power systems efficiently. In this paper, we show the local property of the information of multiple solutions in load flow calculation and its use in voltage instability assessment. It should be noted that this kind of information is formatted in the voltage space rather than in the specified value space. Therefore, it adds difficulties to obtain the information of the specified value space, and the qualitative property in a simple one-machine one-load (two-bus) power system may not be true for multi-machine multi-load power systems. We show our investigations by considering several model systems quantitatively comparing with the two-bus power system. Taking the advantage of the power flow formulation, it can be concluded that the localization of the voltage variation vector that indicates the initial direction of the voltage collapse will provide exact information for distinguishing the problem buses in the system. The nose curves of problem buses can be obtained for monitoring purposes at the same time. With the application of these results and VIPI, an emergency countermeasure is suggested for monitoring and delaying possible voltage collapse in the stressed power systems.