Significant progress in HV cable testing tech

China recently made a significant breakthrough in high-voltage cable testing technology with the successful application of its first domestically developed special test bushing for connecting both inside and outside high-voltage switchgear rooms.

The technology, developed by State Grid Zhoushan Power Supply Co, was applied during the cable tolerance voltage test at the 110-kilovolt Daixi substation in Zhoushan, Zhejiang province.

It effectively addressed a longstanding challenge in the gas insulated switchgear environment — a critical component of power systems — where limited internal space and structural constraints have long complicated testing procedures.

The new test bushing, made from high-strength composite insulation materials, features a modular structure. It is lightweight, resistant to voltages up to 250 kV and is designed for easy installation.

"Today's generation, transmission, conversion and consumption of electricity happen in an instant, which makes traditional power technologies struggle to cope with the intermittent, fluctuating and unpredictable nature of new energy sources," said Sun Zhengyun, secretary-general of the China Energy Research Society.

Sun added that ensuring the safe and stable operation of the power system requires a deep integration of cutting-edge technologies with conventional power infrastructure.

According to the power company, the new solution can shorten test preparation time by 60 percent, improve operational safety by 90 percent, and can be reused, substantially reducing operational and maintenance costs.

In addition, the team developed the technology by conducting data modeling based on domestic and foreign cases to accurately locate the core problem of limited high-voltage lead channels. Through structural design optimization, outdoor series resonant high voltage was safely introduced into indoor terminals while ensuring insulation strength and spatial adaptability, the State-owned power operator said.

Yi Xuedong, head of the research center at the State-owned Assets Supervision and Administration Commission of the State Council, emphasized that as China pursues high-quality economic development, SOEs should further solidify their position as key drivers of technological innovation and lead the energy technology revolution.

"SOEs should continue deepening collaboration among energy think tanks, fostering cooperation between domestic and international institutions, central and local SOE think tanks, as well as those focused on both 'hard technologies' and 'soft sciences' — to drive the new energy security strategy forward with greater depth and effectiveness," Yi added.