State estimation aims to estimate the optimal state variables that can represent the current state of a system based on the measurement set in the power system. The PMU (phasor measurement unit) is a key technology that can directly improve the performance of the monitoring, control and state estimation in the power system. The PMU enables the direct measurement of state variables such as voltage magnitude and phase angle. It also makes it possible to synchronize the measurement set using the GPS time stamp. To improve the performance of state estimation, it is not economical to place PMUs on all buses in the power system, so the PMU optimal placement must be determined. PMU optimal placement can be expressed as a limited optimization problem that secures the observability of the system with the placement of minimal PMUs by identifying the locations at which the PMUs should be installed. In this paper, we present the development of a PMU optimal placement algorithm that can determine the observability by searching the spanning tree of the graph, by which a topological connection relationship is created by measurement set.

状态估计的目的是根据电力系统中的测量集，估计出能够代表系统当前状态的最优状态变量。PMU（相量测量单元）是直接提高电力系统监测、控制和状态估计性能的关键技术。PMU 可以直接测量电压幅值和相位角等状态变量。它还可以使用 GPS 时间戳同步测量集。为了提高状态估计的性能，在电力系统中的所有总线上都放置PMU是不经济的，因此必须确定PMU的最佳放置。PMU 最佳放置可以表示为一个有限的优化问题，该问题通过确定 PMU 应安装的位置，通过放置最少的 PMU 来确保系统的可观察性。在本文中，我们提出了一种 PMU 最优放置算法的开发，该算法可以通过搜索图的生成树来确定可观察性，通过测量集创建拓扑连接关系。