Abstract
To reveal the mechanism of how much impact the protection system can have on the power system reliability, the paper proposes an operational risk evaluation model of stepped current protection. Firstly, the principles of the fail-operation and false-operation of protection relay are described considering operational conditions of power grids, and the truth that fail-operation and false-operation are due to the invalidation of hardware and incorrect protection scheme in the operation is pointed out. According to the scheme of relay protection systems, the tripping setting and time of stepped current protection in grids, two sets of risk indices based on actual protective range and sensitivity coefficient, such as operational fail-operation probability and operational false-operation probability, are deduced. Furthermore, the loss of load risk index incorporating protection misoperation effect is put forward. The application of the presented operational risk evaluation model of stepped current protection is clarified using a typical example to show the practicality and validity of the proposed approach.
| Original language | English |
|---|---|
| Pages (from-to) | 70-77 |
| Number of pages | 8 |
| Journal | Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering |
| Volume | 28 |
| Issue number | 13 |
| Publication status | Published - 5 May 2008 |
| Externally published | Yes |
Keywords
- Current protection
- Fail-operation
- False-operation
- Reliability evaluation
- Sensitivity