C I R E D 18 th International Conference on Electricity Distribution Turin, 6-9 June 2005 CIRED2005 Session No 3 APPLICATION OF A COMPUTATIONAL SYSTEM TO SUPPORT REAL TIME RESTORATION AND SWITCHING ACTIONS IN DISTRIBUTION SYSTEMS Flávio A. B. LEMOS*, Alessandro MANZONI*, Mauro A. da ROSA*, Antonio V. ZAMPIERI* Jaime JEFFEMAN FILHO*, Wilson L. FEIJÓ JUNIOR*, Felipe KOBER*, Lucas L. dos SANTOS* Rodrigo BERTANI†, Luciano BRASIL† Electrical Energy System Group - GSEE *Pontifical University Catholic of Rio Grande do Sul – PUCRS - Brasil †RGE Rio Grande Energia S.A - Brazil E-mail address: lemos@ee.pucrs.br INTRODUCTION This paper presents a graphical computation system developed to help system operators in task of distribution system restoration process in real time. Moreover, the system can be used to create switching actions planning to support maintenance, since this action affect the reliability index. The restoration and switching actions are executed using configuration techniques and load curve data, obtained from simulation using typical load curves and energy data. For support actions of restoration, the load curves are adjusts using real time information get from SCADA system. In order to illustrate the potential of system to restoration and switching actions are present results of the application in a distribution control center, with 5 substation, 35 feeders, 1027 switches, 136.495 customers and a demand of 500 MVA. The system can be used for restoration training as well, since the historic database store the past operation (digital and analogic) state. The system was implemented using objected oriented modeling (OOM) and C++ on Windows Operation System, Oracle Database and OpenGL Technology. THE PROBLEM OF DISTRIBUTION SYSTEM RESTORATION AND RECONFIGURATION Distribution systems are getting more larger and complex systems. These characteristics together with a predominance of overhead networks lead to system to present local failures or partial outages (short circuit, overvoltages due lighting, overloads and outages due to accidents, e.g. car crash), such as restoration actions usually deals with the reconfiguration of the distribution network from the restorative state to normal state, since this situation able to get the information of unfaulted network [1,2]. Nowadays, costumers require electrical services with high level of quality and reliability, and regulatory agencies have imposed penalties for violations of limits operation and low level of reliability index. Considering these circumstances, it is very important and mandatory to restore the electrical supply quickly and safely after a fault occurrence, since this may affect reliability indexes and voltage performance index of the system. These characteristics require significant attention and strategies to deal with restoration and reconfiguration problems, since fault isolation, restoration time and service restoration to unfaulted areas can affect reliability index (SAIFI and SAIDI), and voltage performance index of the system. The planning of power system restoration and strategic actions to deal with switching plans to support maintenance programming is a very hard task. The problem of distribution system restoration is a complex decision-making and control problem, since this problem can be described as a multi-objective, multi-stage, combinatorial, nonlinear, and constrained optimization problem [3,4]. Reference [1] presents a large number of selected paper and discussion on power system restoration. In [5] is presented five reports and comments on system operation challenges, including discussion about Energy Management System - EMS. In [6] are presented methods based on expert system for restoration process. References [7,8] covers the aspects of tools used to effective system restoration training programs, as well the use of training simulators for testing and verifying the restoration plans and ability to respond to a real incident. A conceptual framework for computer- aided monitoring and assessment during system restoration is presented in [3 ]and reference [9] describe heuristic search approach for distribution system restoration. The ability to operate in such environment with an acceptable degree of security, reliability and quality, while being economically competitive, using only human experience is become impossible. Many distribution utilities have been maintained a written restoration procedures and heuristics routines. However, in the deregulated electricity industry there is focus on economic issues associated with new competitive market environment. Under these circumstances, a fast and reliable computational system able to help system operators to maximize customer supplied and to minimize restoration time and control actions is essential in modern control systems. Usually, this application is a module of a Distribution Management System (DMS) [1]. Many electrical distribution utilities have developed plans, schemes and computational systems for restoration to meet their particular needs; however, the essence of restoration plans is similar for all distribution utilities. The resume and essence of restoration problem can be summarized as: • Minimize restoration time; • Maximize load allocation; • Minimize control actions. Next sections present an overview of a graphical computation system developed to help system operators in task of distribution system restoration in real time and switching actions plans to support maintenance, operation planning, and operator training. THE SYSTEM STRUCTURE The main aim of the system called GSEE_RESTORE is to generate a restoration plan using real time information.