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.

The development of power system control facilities in China is surveyed. The special emphasis is placed on the automation facilities in power system dispatching centers. The dispatching center hierarchy in China is first introduced and then the development of energy management system (EMS) and distribution management system (DMS) in China is reported. Finally, the development of integrated substation automation and feeder automation are also introduced.

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.

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。

提出了一种规范化的计算机故障分析计算方法.该方法不用进行纵向故障的支路破口，也不用进行线路中间故障的新增节点等处理，保持故障前网络方程不变，任何多重复杂故障，包括不对称短路、跳闸、重合闸都在一个较小的附加故障电路上进行，特别适合于计算机进行复杂故障计算。

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。

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。

随着电网互联和电力体制改革步伐的加快，对电网运行的调度和控制提出了许多更新更高的要求，传统的调度中心EMS的结构和功能将发生很大的变化。为适应这一变化，文中认为现代能量控制中心的概念应当扩展，特点是高度的信息化、智能化、集成化和自动化。其功能由安全发展为安全与经济的协调;局部控制发展为全局分层控制；离线分析发展为在线分析；开环控制发展为闭环控制；在线稳态分析发展为在线暂态分析。

地区电网EMS应用功能是地区电网调度和商业化运营的重要辅助决策工具，是继SCADA实用化后，地区电网调度自动化技术发展的必然趋势。但传统的EMS应用软件面向发输电系统，主要在大区电网省网中应用。通过研究地调和网（省）调在调度管理职能、电网运行特点和自动化水平等方面的不同，设计和开发了面向地区电网的EMS应用软件系统，该系统在功能、算法和应用方法上都具有地调特色，并已在国内多家地调投入在线运行。

An integrated security analysis and optimal power flow package has been implemented in the North East China Power System Control Center. the functions imple-mented in this package include Stata Estimation, Short-Term Load Forecast, External Network Equivalent, Automatic Contingency Selection, Security Assessment and Correction. Oprimal Power Flow. This paper intro. duces, in some details, the functions implemented, the algorithms adopted in the package and the real-time oper-ation experiences. The outstanding featrue of the packageis that it integrates the security and optimization together to get a better merit. The improved ACS algorithm in this paper is a sensitivity based one with bOth real power overload and voltage violation considered. The security as-sessment function is based upon a sparse vector factor modification and both branch outages and generator outages are considered in the algorithm. A P-Q Alternate Approximating OPF algorithm is proposed in this paper and implemented in the package. The formulation of the OPF algorithm is given. The application of this package toNorth East China Power System is described and the oper-ation experiences are given.