Quantitative assessment of protection system reliability incorporating human errors

Abstract

The protection system plays a vital role in maintaining a high degree of service reliability in present-day power systems. Considerable work has been done to examine different aspects of protection systems and their associated reliability. All of the reliability predictive methods are based solely on equipment failures, neglecting the human component of the protection system. In this paper, a modified Markov model is presented that incorporates human errors in reliability evaluation of protective devices. Two main types of relay failure (failure to operate and inadvertent operation) are taken into account in the proposed model. The model also considers routine test inspections, the self-checking facility of digital relays, and also common cause failures of protective devices and protected components. Numerical studies show the influence of human errors on protection system reliability.

Research on Hidden Failure Reliability Modeling of Electric Power System Protection

“…Ref. [1][2][3][4][5] are the first to explore hidden failures in protection system carefully, later many experts carried research on protection hidden failure and its contribution to protection system reliability and power system reliability and have obtained many good results [6][7][8][9][10][11][12][13][14]. Now, CBM (Condition-Based Maintenance) is presented to apply in power system and protection system in China, hidden failure of protection is defined as a function defect of protection device before; under new CBM circumstance [15,16], hidden failure is defined as a hidden defect of protection that can't be detected by means of CBM such as on-line self-checking and monitoring system, and it may result in mal-operation or non-operation of protection system under certain condition, for example, settings of protection don't change according to the operation mode of protected equipment.…”