Improved Transformer Differential Protection with System Based Testing according to IEC 60255-187-1

Improved Transformer Differential Protection with System Based Testing according to IEC 60255-187-1 for Medium and Large Power Utilities in Asia.

The performance of the protection relay is usually tested by steady-state testing. The typical testing concept is the functional test focus on logic and mechanism verification. However, this is no longer sufficient against the rapid change of the demand. The recently launched protection testing standards IEC60255-121 and 187-1 introduced the real-world scenario, a system-based approach. The system-based testing philosophy highlighted the relay application and implementations in the existing network. However, these standards were designed for protection relay manufacturers. Our paper suggested the approach to adopt the testing philosophy of the IEC 60255-121 and 187-1 standards and introduced the system based simulation test collection with both the selective IEC 60255-121/187-1 test cases and utilities unique setups. The special configurations are mainly about the CT and VT test data, transmission line mutual coupling, transient behaviours of the faults, transformer internal faults, etc. Our study also introduced the adequate insight collection flow (based on the JTBD model from McKinsey). Our paper will also illustrate some real examples of how power utilities adopt the IEC 60255-121/187-1 standard to speed up the relay acceptance process.