Application of a knowledge based system for voltage monitoring and control on the NGC system

This paper reports on an on-going project at the Institute Superior Tecnico (IST) on behalf of the National Grid Company (NGC) aiming to contribute to the adoption of Knowledge Based Systems (KBS), into their Energy Management System (EMS). The paper discusses the design and implementation of VCRM, a system for Voltage Control and Reactive Management based upon both OPF and knowledge-based techniques. A similar on-line application, presented by Barruncho has been developed and installed at the national energy control centre of the Portuguese national utility, Electricidade de Portugal (EDP). The operational and implementation experience gained has been of great value as input information for the NGC project. In this application the OPF calculates an hourly voltage schedule and the rule-based system suggests remedial actions whenever voltage violation alarms are detected by the state monitoring which follows every state estimation. Significant characteristics, operational specifics and control issues of the NGC transmission network, which are related to voltage/VAr management, are presented and discussed in this paper. The new application described is for tertiary voltage control, to contribute to the centralized on-line definition of compensation settings for improved effectiveness of the plants, in a coordinated way with the local control schemes.