New electricity testing benchmark is created

State Grid Xinjiang Electric Power has recently completed China's first line-side partial discharge test on a 750-kilovolt shunt reactor at the Tacheng substation.

This achievement, made in early September, addresses a long-standing challenge in acceptance testing and marks a technological breakthrough in on-site diagnostics for 750 kV voltage level grid equipment.

Acting as a stabilizer in ultrahigh-voltage transmission systems, shunt reactors' internal insulation is prone to partial discharge under high voltage and vibration. However, due to the high capacity of 750 kV reactors, conventional methods have long faced limitations in providing precise on-site detection, creating technical bottlenecks.

To address this challenge, State Grid Xinjiang implemented the corporate reliability enhancement directive for ultrahigh-voltage reactors. Beginning in August, it coordinated with its research institute and extra-high voltage branch, drawing on peer experience to propose an innovative resonant testing method. This approach uses the transmission line itself as a compensation capacitor, interacting with the reactor's inductance to overcome traditional detection limits.

After five rounds of optimization, the team executed the test on Sept 7 at the 750 kV Tacheng substation, applying the method to a three-phase reactor and a 10-kilometer line. By simulating actual operating conditions and raising voltage to rated levels, they employed multidimensional monitoring techniques to capture critical signals. A 48-hour operation concluded with all parameters normal and partial discharge below 100 picocoulombs, confirming the method's feasibility.

The test established a pioneering methodology for line-side partial discharge testing on 750 kV shunt reactors, creating a replicable "Xinjiang model" for future acceptance testing of similar equipment, the company said.

Next, State Grid Xinjiang will focus on developing an integrated field-testing platform to enhance operational efficiency, thereby strengthening the technical safeguards for Xinjiang's main power grid.