UHV test line initialization corona characteristic research based on optical fiber current measurement technology

Transmission line corona characteristic research is one of the key technologies in 1000 kV AC UHV transmission and transformation project in our country. Based on optical fiber current measurement technology, an optical fiber digital UHV corona measurement system is designed in this paper. The system achieves 0.2 level in IEC60044-8 standard, and it is able to measure voltage, current of UHV test line accurately. With this system, corona characteristic of single phase (C phase) conductor is tested, in Wuhan High Voltage Research Institute outdoors test site. The test line is about 200 m long. According to the test data, corona parameters is calculated out, and initialization corona characteristic of the test line is researched. The result shows that, the corona measurement system in this paper is available. With the increase of test voltage, corona loss rises as a exponential function curve approximately. When discharge appears on grading ring and test line, the corona loss and resistance current rise apparently. The corona kneel point is not apparent. With the increase of voltage, equivalent capacitance of test line changes little. According to this situation, it can be considered to adopt voltage resonance voltage loading mode to research corona characteristics.