Research On Condition-based Maintenance Strategy Of Intelligent Substation Relay Protection System

Relay protection is an important foundation for ensure the stable operation and safe operation of the power grid, how to improve the reliability of the relay protection system has been a high-profile topic. Reasonable maintenance mode is one of the primary means to improve the relay protection system reliability. Condition-based maintenance compared to the traditional way of planned maintenance, has outstanding advantages in ensuring the safe operation of equipment, improve equipment utilization and reduce maintenance costs, which has been become the main development direction of relay protection and power equipment maintenance techniques.With the development and application of intelligent substation technology, relay protection system construction model compared with traditional way has undergone major changes, which brought many new challenges to the intelligent substation relay protection technology. At the same time, the intelligent substation secondary system has the technical characteristics of good online monitoring method and easy to share information, which provide a strong support to realize the condition-based maintenance in relay protection system. Therefore, the research for intelligent substation relay protection system condition-based maintenance technology has important theoretical and practical significance to improve the operation of intelligent substation secondary system maintenance efficiency and management level, promoting the development of intelligent substation technology.Intelligent substation secondary system structure is complex and contains many components. Analysis and evaluation of major fault protection and on-line monitoring methods in relay protection system, which is the premise and foundation to achieve condition-based maintenance. According to the operational characteristics of intelligent substation protection system, the main failure mode, the generation mechanism, performance characteristics, and online testing methods for each component were systematically analyzed. Based on the characteristics of different faults and anomalies of the components, proposed basic strategy for condition-based maintenance and troubleshooting, providing the basis for assessing the operational status and condition-based maintenance programs.Based on the state evaluation of relay protection system condition-based maintenance technology has been applied in engineering practice, and accumulated useful experience. Paper to draw on existing related research of relay protection system condition-based maintenance, proposed condition-based maintenance program based on the evaluation of the health status of intelligent substation relay protection system. In this study program, status indicators for each component of the evaluation system were estabilished for intelligent substation relay protection system, different state indicators calculation methods were proposed. These practical maintenance program seemed good with the existing relay protection equipment condition-based maintenance technology, and conducive to master the use of the site run.Based on the evaluation of the health status of protective equipment maintenance technology has easy to operate, easy to promote the use of other features, but to determine its condition-based maintenance cycle is relatively simple, it is difficult to give full play the advantages of condition-based maintenance technology. Papers from the engineering practical point of view, put forward a condition-based maintenance program based on the probability of failure prediction. The scheme adopts the weibull distribution model on the basis of the component failure rate distribution curve modeling, using the least squares fitting technology for optimal estimation of model parameters calculation.The method through modification of the basic failure rate curve and the equivalent of military age regression, in order to gauge individual differences and component, familial defects, maintenance factors and the influence of the current running status on the failure rate, improve the failure rate prediction accuracy. On this basis, combined with the existing protection system operating experience and reliability theory, achieving the optimal solution of relay protection system maintenance intervals. The example analysis verify the rationality and feasibility of the state overhaul plan.Finally, the full text was summarized, and the next research direction was prospected.