“Substation on wheels” powers zero-outage renovation of aging power grid

Taizhou in east China's Zhejiang Province has leveraged vehicle-mounted mobile substations to enable uninterrupted power supply during the upgrading of aging power infrastructure, effectively resolving the long-standing conflict between grid renovation and power service continuity.

Recently, a fully equipped mobile substation — integrated with main transformers, circuit breakers and complete switchgear systems — has been successfully commissioned at the 110kV Jingdu Substation in Linhai, Taizhou. Functioning as a portable backup power hub, the wheeled substation requires no fixed foundation and can be flexibly deployed across construction sites to bridge power supply gaps during infrastructure overhauls.

Traditional substation upgrading typically necessitates prolonged power cuts, inevitably affecting residential livelihoods and industrial production. Built and operated for years, the Jingdu Substation was set for comprehensive automation upgrades and replacement of outdated 10kV switchgears. A full-scale station overhaul under conventional arrangements would have triggered extensive outages across the Duqiao area.

To eliminate service disruptions, State Grid Taizhou Power Supply Company adopted a proactive transitional solution by deploying the mobile substation as a temporary power source. The mobile unit undertakes regional power loads throughout the renovation period, ensuring stable and consistent electricity supply for local households and enterprises with barely perceptible grid fluctuations.

At the construction site, professional technicians completed precise 110kV cable connections, followed by systematic high-voltage testing and protection commissioning for core mobile substation equipment. The team also standardized equipment labeling and compiled formal operating guidelines, laying a solid foundation for the unit's safe, stable and standardized operation.

The project strictly follows a standardized three-step workflow: load transfer prior to renovation, full renovation under zero-load conditions, and smooth load switchback upon completion. The mobile substation is first interconnected to the power grid to take over core power supply functions. After stable operation is verified, the original substation is de-energized for comprehensive upgrading. Once renovation work concludes, power loads are seamlessly transferred back to the newly upgraded station. This innovative model ensures construction safety while delivering zero-outage grid renovation.

Since State Grid Taizhou Power Supply Company launched its three-year aging substation upgrading initiative in 2024, the city has entered an intensive phase of power grid renewal. A batch of aging, long-serving substations with potential operational risks are being renovated and upgraded in a phased manner, steadily improving the reliability, intelligence and resilience of the local power grid.