Dongwu 1000kV UHV AC Substation goes Live after Expansion

On June 28, the expanded Dongwu 1000kV UHV AC transmission substation resumed operation after commissioning. The expansion is a key infrastructure project included in the Outline of Integrated Development of Yangtze River Delta. Upon completion, the substation becomes the world’s most powerful AC transmission substation with 5 UHV AC transformers, 15-bay gas insulated switchgears (GIS), and a capacity of 15 GVA.

This Suzhou-based substation is a major hub for the UHV AC double-ring grid in East China, and critical for South Jiangsu grid and Shanghai grid to receive electricity from rest of China. As an important project under the National Action Plan for Air Pollution Control, the substation was built up in September 2016, running with two main transformers. Expansion was made later due to growing demand for electricity in South Jiangsu, but did not manage to meet the fast-growing need soon after. Another round of expansion became an imperative.


Dongwu 1000kV UHV AC substation

This new expansion was approved by the government in June 2019, and began construction in October of the same year. Challenges such as live-line environment, seasonal rainfall, and the COVID-19 left the project only seven months for working. In order to serve the summer peak of power consumption, the project was among the first batch to resume work amid the pandemic. Detailed schemes were carried out for the construction which covered site disinfection, enclosed management, health monitoring, trace inspection, and emergency response. All parties involved took responsibilities and overcame difficulties to advance the project while containing the pandemic. They put safety the first priority and completed the expansion with high quality.


Testing GIS before installation

Amid the ongoing pandemic, the project introduced a new model of commissioning by on-site personnel supported by remote guidance via video conferencing. 109 tests were conducted on schedule for main transformer switching, reactive compensation equipment switching, system close-loop and open-loop operation, overvoltage, and electromagnetic environment measurement, among others. The substation was put into operation after commissioning completed at 1:36am on June 28, with the system being stable and all equipment in good condition.

The expanded substation is expected to increase the supply capacity of South Jiangsu grid by about 1 GW, further improve the safe and stable operation of the UHV AC double-ring grid in East China, secure power supply during the summer peak, and provide new growth drivers for the integrated development of the Yangtze River Delta.

Sources: Department of UHV Transmission Projects, State Grid Jiangsu Electric Power Company


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Leak Rate:1 x 10-8 ml/s ,0.1ppm,[With optional capillary inlet,1 x 10-10mL/s SF6]

Concentration Sensitivity:0.01 ppm

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