The world’s first 550-kilovolt triggered bypass gap designed for safeguarding converter transformers against explosion has successfully passed long-duration current and pressure endurance tests, marking the product’s full validation.
Jointly developed by Henan Pinggao Electric Co., Ltd. under China Electric Equipment Group Co., Ltd. (CEEG), together with China Electric Power Research Institute, Xi’an Jiaotong University, and Shandong Taikai High Voltage Switchgear Co., Ltd., the product represents a breakthrough in sub-millisecond ultra-fast bypass protection, filling a global technological gap.
Converter transformers are key components in ultra-high-voltage direct current (UHVDC) systems. In the event of internal short circuits, high-energy arcs can rapidly generate high-pressure oil gas, posing serious risks of casing rupture and explosion — making reliable explosion protection a critical challenge.
The new innovative bypass gap features a single-break structure with dual-sided triggering and a plasma jet enabled by exploding wires. This setup enables rapid conduction in under 1 millisecond at ultra-low arc voltage in oil. This swiftly extinguishes the arc in the transformer oil and transfers the fault to the air gap, where it is cleared by an AC circuit breaker — significantly reducing arc duration and energy, and effectively mitigating explosion risk.
The device will soon be deployed at the UHVDC Gusu Converter Station as a demonstration project. It can also be adapted for fault bypass protection in other critical power electronics equipment, offering robust support for the safe and stable operation of UHVDC systems.
(Executive editor: Yuan Ting)
