Hangzhou, Zhejiang: Small Microgrids Break the ‘Island’ Dilemma, Making Mountain Power Grids ‘Not Isolated’

“The water level is high now, but there are no hidden dangers in the lines and equipment.” On the morning of July 30, Yu Jianping and his colleagues from the Hangzhou Power Supply Company went to Xiguan Village in Tianmushan Town to conduct a special inspection of the lines.

Near the Xiguan No. 3 public transformer, the rushing stream, carrying sand and mud, surged down, and the water level continued to rise at a visible rate. The rapidly rising stream constantly impacted the bamboo and rocks on the shore. The maintenance personnel adopted a ‘drone + manual’ three-dimensional inspection mode, focusing on inspecting the distribution lines near potential geological hazard points and reinforcing the towers that are susceptible to mountain floods.

Affected by the outer circulation of Typhoon No. 8 ‘Bamboo Grass’, Hangzhou experienced heavy rainfall. Currently, all 31 emergency command centers at the city and county levels under the Hangzhou Power Supply Company have been activated, and the majority of cadres and employees are on duty 24 hours a day. As of 9:00 today, the company has dispatched 1,987 inspection personnel and 824 vehicles, covering 9,301 underground distribution rooms, 101 distribution towers at ‘two mountains and one bend’, and 40 construction project sites. They have completed inspections of electrical facilities, self-provided power sources, and low-lying distribution facilities for 210 users, and eliminated drainage hazards at 33 low-lying charging stations and 384 operational photovoltaic power stations. They have mobilized and deployed 257 emergency teams with 2,635 personnel, and organized 42 emergency rescue backbone teams to be on standby.

In Lin’an, Hangzhou, the unique geographical environment and complex terrain conditions pose severe challenges during the typhoon season. The Tianmu Mountain Range crisscrosses the area, and most of the power grid lines are erected along the mountain slopes, making them highly susceptible to secondary disasters such as mountain floods and landslides. Especially in mountainous towns like Longgang and Daoshi in the western mountainous areas, the treacherous terrain makes them prone to natural disasters like mountain floods, forming ‘isolated islands’, which have always been key and difficult areas for typhoon and flood prevention.

Facing this special challenge, the Hangzhou Power Supply Company has continuously strengthened the construction of disaster prevention and mitigation capabilities in the power grid in recent years. To address the weak links in the mountainous power grid, the company has innovatively created an intelligent power protection system of ‘hydropower microgrid + 5G quantum communication’, and has built distributed microgrids in nine key areas such as Qianqingtang and Maxiao, effectively solving the ‘power island’ problem in mountainous areas. Especially the Tianchi-Tianlu 35 kV interconnection channel, which was completed and put into operation in early 2025, has significantly improved the reliability of the interconnected power grid in the western mountainous areas.

“The 110 kV Longgang Substation is an end substation. In extreme cases, there is a risk of power loss at the Longgang Substation and the downstream Daoshi Substation and Xiangjian Substation, which would mean that the three towns of Longgang, Qingliangfeng, and Daoshi would be in a power outage,” said Cheng Weidong, Director of Operation and Maintenance at the Hangzhou Power Supply Company. “To change this passive situation, we have achieved emergency power supply for the power loss areas by enabling the 110 kV Changhua Substation to supply power to the Longgang Substation and 10 kV lines through the Tianchi-Tianlu 35 kV interconnection channel.”

In addition, considering the inconvenient transportation in mountainous areas, the company has established a ‘1+N’ emergency repair mechanism, setting up emergency repair points with resident repair personnel and equipment. At the same time, they have established an information sharing mechanism with meteorological and water resources departments to achieve intelligent linkage analysis of typhoon paths, rainfall forecasts, and power grid risks.

Through years of practical exploration, State Grid Hangzhou Power Supply Company has established a disaster prevention system for mountainous power grids characterized by ‘technological support, three-dimensional prevention, and rapid response’, providing reliable assurance for the safe operation of mountainous power grids. Next, the company will expand the coverage of ‘hydropower microgrid + 5G quantum communication’ to enhance the resilience of mountainous power grids. At the same time, it will organize professional technical teams to conduct a ‘look back’ on typhoon-damaged lines over the years, analyze weak links, and continuously improve the disaster prevention and resistance capabilities of the power grid, providing strong power support for the economic and social development of mountainous areas. (Text/Fu Yunxiao, Photo/Wu Chen)