Research on sub-station-area breaker failure protection based on the principle of current differential

Abstract

On the basis of the principle of breaker failure protection delay and the analysis of the main factors which affect the protection, a sub-station-area breaker failure and dead-zone protection technical scheme based on the current differential principle is proposed. In this scheme, an incomplete current differential protection is structured by the breakers current transformer (CT) of the non-fault area, which is adjacent to the fault area. When the criteria of the incomplete current differential protection are satisfied, the adjacent breakers will trip to realise the isolation of the fault. This scheme is not only affected by the CT tailing and CT saturation, but also greatly reduces the time delay of breaker failure protection and achieves the free protection setting. The implementation of the project adopts an expandable architecture designed with the master slave mode, which could be achieved by high reliability with a flexible configuration of engineering and not relying on external time signals. Moreover, this scheme has the advantages of versatility and easier to implement. Also, it is preferable due to practicability and extended significance to popularise.

Keywords

• current transformers
• circuit breakers
• relay protection
• power transformer protection
• fault diagnosis
• substation protection
• failure analysis
• delays
• breaker failure protection delay
• dead-zone protection technical scheme
• current differential principle
• incomplete current differential protection
• breakers current transformer
• CT
• nonfault area
• fault area
• adjacent breakers
• free protection setting
• substation-area breaker failure protection
• fault isolation
• master slave mode
• CT tailing
• CT saturation