MODEL-BASED ANALYSIS OF PROTECTION SYSTEM PERFORMANCE

Following a power system fault, protection engineers have to analyse t he scheme activity to ensure correct operation. To aid them in this ta sk, data gathering systems are increasingly being fitted to the power system. However, during extreme operating conditions the volume of dat a made available by these systems can be overwhelming. To help overcom e this, knowledge-based systems have been developed and installed at S cottishPower's corporate headquarters to extract the relevant 'informa tion' from the Supervisory Control and Data Acquisition (SCADA) system 'data'. The paper reports on the next stage of decision support for t he protection engineers which builds upon the diagnosis provided by th e knowledge-based systems. This enhanced support is provided by a mode l-based diagnostic system which provides automatic analysis of the ava ilable fault recorder data. This system utilises the most appropriate techniques employed by existing model-based diagnostic systems. A nove l approach for handling tolerances associated with the operating times of protection scheme components is introduced, thus enabling modellin g and measurement inaccuracies to be dealt with.