中文摘要：

分布式状态估计可用于在线生成互联电网一体化潮流断面。针对无约束优化问题描述的全网状态估计,提出了一种新的分解协调算法。采用节点撕裂法对互联电网进行切分,将全网状态估计问题的KKT（Karush-Kuhn-Tucker）条件方程分解为协调侧和分区侧2个部分。在边界节点状态给定情况下,各分区电网可独立求解分区侧KKT条件方程,获得自身状态估计结果。此时,若协调侧KKT条件方程的残差满足设定条件,则可判断全网状态估计收敛。由此出发,可构建全网状态估计分解协调计算模型,通过求解协调侧KKT条件方程获得边界节点状态修正量,从而调整分区状态估计结果,使其达到一致收敛。文中分别采用JFNG（Jacobian-free Newton-GMRES（generalized minimal residual））算法和逆Broyden拟Newton法这2种方法实现协调侧KKT条件方程求解过程。IEEE14节点系统、IEEE39节点系统和实际电网1165节点系统的测试结果证明,所提出的分布式状态估计算法具有较高的准确性、收敛速度和计算效率。

英文摘要：

The distributed state estimation is a novel and effective solution for achieving unified state estimation results of the whole power system. This paper proposes a new distributed state estimation algorithm, which is based on decomposition-coordination of the non-constrained optimization problem. By dividing the KKT （Karush-Kuhn-Tucker） condition equations of the state estimation of the whole power grid, two subsets of the KKT condition equations are obtained for both the regional power grids and the coordination sides. With given states of the boundary buses, the state estimation of the regional power grids can be worked out individually by solving the corresponding KKT condition equations. Then, if the demand to errors of coordination equation is satisfied, the overall state estimation is converged. Therefore, solving the overall state estimation is equal to solving the coordination equation with the constraint as that all regional state estimations are converged with the given states of the boundary buses. Moreover, to simplify the data exchange interfaces, the JFNG （Jacobian-free Newton-GMRES （generalized minimal residual）） and inverse Broyden quasi-Newton methods are utilized to solve the coordination equation, which makes the proposed algorithm being compatible with the legacy computing resources. Test results of the IEEE 14-bus system, IEEE 39-bus system and the North China 1 165-bus system show that the proposed algorithm can obtain the exactly same results as the centralized ones as well as converge fast and robustly, which enables it to be applied in the wide area networks.