Power systems in China are being interconnected into a unified one which is running according to its physical rules (KCL, KVL and Ohm’s Law) but being managed and controlled by own regional control centres separately and independently. Each sub-system in the unified power system gathers SCADA data real time from its own regional network and makes dispatching decision itself independently. How the Energy Management System (EMS) in each regional control centre follows the variation of whole power system correctly and timely is a very concerned and real problem especially when some transmission line outage occurs in its external network. To solve this problem, some interaction and coordination between control centres in different hierarchies are needed to ensure that a consistent result is achieved by each of the separate control centres. Based on the principle of network piecewise, decomposition and coordination calculation modes with three different interaction levels for real time network analysis applications are proposed in this paper. Through interaction and coordination between master and slaver control centres, a consistent network analysis result with whole network can be achieved at the sub-system level. A practical and efficient real time tracking equivalence system (TES) for EMS applications is developed, implemented and put into on-line operation in this paper. Correctness and exactness of the EMS simulation in sub-systems by using TES have been greatly improved.

提出电网控制中心安全预警和决策支持系统按时间、空间和对象等3个维度进行设计。在时间维上，将电网事故看做事件的发展过程，分析中考虑电网暂态、动态和稳态等状态变化；在空间维上，考虑电网调度管理体制的分层分区，电网分析应分解协调进行；在对象维上，既考虑功角稳定和电压稳定，又考虑安全和经济。文中描述了系统的总体设计框架和功能，论述了系统的特点，给出了部分计算结果。

介绍了运行风险评估的基本定义，总结了电力系统运行风险评估与传统调度确定性分析方法和电力可靠性研究相区别的特征。电力系统运行风险评估的主要目的有2个：一是对电力系统运行中的不确定性因素进行定量评估，建立运行风险指标体系；二是以运行风险指标为决策手段，综合协调电力系统的安全性与经济性。与核电厂运行风险进行类比，分析了电网运行风险评估的发展前景。概述了运行风险评估的相关研究已分别在元件级的安全评估和系统级的安全评估2方面取得的一些重要进展，介绍了它们所借鉴的传统的可靠性研究方法，阐述了风险评估的研究思路。

电网互联为一体，而电网调度却分层分区，需要在线进行电网分解协调稳定分析计算。文中将暂态稳定分解协调计算的各种计算策略统-在计算模式-协调计算方式-外网等值的三维坐标图中，并论述了相互间的演进关系；研究了协调算法、计算速度、通信等问题；设计了一种实用的暂态稳定分解协调计算算法；引入时窗和移窗技术提高算法收敛性，减小通信开销。算例表明，这种算法具有收敛性好、计算结果精度高、对通信质量依赖性低以及对迭代初值的误差不敏感等优点。

A loop-flow-based method for capacitor optimization in distribution systems is proposed in this paper. An optimization algorithm that combines both economic and secure objectives together in a single function for optimal capacitor sizing is presented. Line-current flow, which is a direct indicator of power loss and line loading, is taken as the controlled variable in this optimization algorithm. Therefore, the algorithm has a simple formulation, and is particularly suitable for use in the analysis of radial and weakly meshed distribution systems. An efficient strategy is designed to search for the optimal solution. Because the objective function for the optimization is clearly a quadratic of line-current flow, the convergence character of this algorithm is close to linear and a small iteration is needed in the optimization process. Digital tests have been done to show the validity and efficiency of this algorithm.