Improved travelling wave protection for extra-high-voltage/ultra-high-voltage transmission lines

Abstract

Travelling wave protection has some very attractive advantages such as fast operation speed, immunity to load condition, immunity to power swing, immunity to charging current, and immunity to series compensation. Consequently, travelling wave protection is deemed very suitable for extra-high-voltage/ultra-high-voltage transmission line protection applications. However, its practical application has some challenging issues, especially in regard to security and reliability. For example, harmonics may cause wrong fault direction detection for the classic travelling wave pilot protection, and can even lead to mal-operation in some cases. How to improve the security and reliability under such practical operation conditions is, therefore, a key topic in the research of travelling wave protection. A novel travelling wave pilot protection solution will be discussed, which is based on some new methods such as 4-polarity comparison, a time synchronised pilot protection scheme, and high-frequency unblocking. The analysis and simulation results show that the proposed solution has much better security and reliability than the classic travelling wave pilot protection.

Keywords

• power transmission protection
• power transmission lines
• power transmission reliability
• power system security
• security
• reliability
• time synchronised pilot protection scheme
• high-frequency unblocking
• extrahigh-voltage-ultrahigh-voltage transmission line protection applications
• travelling wave pilot protection solution
• series compensation
• fault direction detection
• 4-polarity comparison