841 / 2019-04-29 22:14:41

Operation Condition Assessment Method and Its Practical Implementation for Protection Systems

Operation condition assessment, protection system, condition monitoring, fault detection, communication networks

Protection systems serves as the guardian of power grids, isolating and clearing failures as soon as they occur. Ensuring reliable protection for primary equipment, i.e., the reliability of protection systems, is always an essential security task for power systems. With the application of networked protection scheme and advanced information and communication technology (ICT), protection systems have gradually become cyber-physical complex systems. Consequently, any single failure may lead to incorrect tripping or malfunctions or even eventually result in the cascading failures of power systems. In this context, the operation condition of a protection system and its influences have become more complicated.
Based on historical or real-time data, an operation condition assessment (OCA) can deduce the status of a system within a certain time interval. Whole-view and reasonable OCA results can provide references for fault diagnosis, condition-based maintenance, and intelligent alarming, therefore ensuring the reliability of protection systems. With the development of sensors and condition monitoring technologies, more real-time monitoring data can be utilized in the OCA. Compared with historical data, the volume, diversity and time distribution of these real-time data are larger and far more suitable for reflecting the current status of a system.
However, there are two challenging problems and disadvantages in the existing OCA methods:
(1) A whole-view and systematic OCA method is lacking, since published approaches mostly focus on singlefunction components or single events.
(2) The assessment efficiency is relatively low, and the monitoring information is not fully utilized.
To address these two drawbacks, this paper aims to propose a systematic and efficient OCA method that is essential for a well-monitored and reasonable-assessed protection system. A well-monitored and reasonable-assessed protection system can lead to the improved operation and reliability of power systems. In this paper, a systematic and efficient operation condition assessment (OCA) method and its practical implementation for protection systems are proposed. Considering the device configuration and information transmission scheme, a protection system operation condition model (PSOCM) is developed. Based on the PSOCM, an OCA method is designed to assess the statuses of devices, information flows, information transmission branches and relay functions. To verify the effectiveness of the proposed method, a master-substation operation condition assessment system (MS-OCAS), which utilizes real-time monitoring and other raw data, is demonstrated. As shown by the experimental results for a 110 kV IEC 61850-based substation, the proposed method and system can realize whole-view OCA of protection systems and can dramatically increase the maintenance efficiency.