Effects of Protection System Hidden Failures on Bulk Power System Reliability
2006 38th North American Power Symposium
Protection system hidden failures have been recognized as a contributing factor to power system cascading outages. However, in the current bulk power system reliability assessment practice, protection systems are generally assumed to be perfect, and the impact of protection system hidden failures are not taken into account. In this paper, a systematic methodology is proposed to evaluate the effects of protection system hidden failures on bulk power system reliability in the general bulk power
... eneral bulk power system reliability assessment procedure. In the proposed methodology, a breaker-oriented bulk power system network model is developed to include detailed system substation configurations and protection system schemes. Any protection system constituents, such as transducers, relays, and circuit breakers, may suffer from hidden failures. Although hidden failures existing in transducers and relays can be detected considerably by advanced system real-time monitoring and analysis technologies, such technologies do not detect the trip abilities of circuit breakers. To conduct the analysis of hidden failures in circuit breaker trip mechanisms (CBTMs), the probabilistic model of the CBTM is built, based on which a hidden failure effects analysis method is developed to obtain contingences resulting from CBTM hidden failures. Such contingencies as well as other contingencies resulting from independent outages and common-mode outages are subjected to a security-constrained adequacy evaluation approach to evaluate their influence on system reliability. The proposed methodology is demonstrated with a breaker-oriented 24-substation reliability test system, which is derived from the IEEE 24-bus reliability test system by integrating explicit substation and protection system models in the network model. Evaluation results show that protection system hidden failures downgrade the system reliability level because they lead to the outages of undamaged equipment following initial system disturbances. Index Terms -Protection system hidden failure, circuit breakeroriented substation model, bulk power system reliability assessment, circuit breaker trip mechanism, advanced real time power system monitoring and analysis, security-constrained adequacy evaluation.