What Are the Standard Substation Voltage Levels in China?

China’s power network uses several voltage tiers, each designed for a different distance and load. substation voltage levels help explain how electricity moves from large generating stations to factories, towns, and homes. A transmission substation may handle 500 kV or 750 kV, while regional networks commonly use 220 kV or 110 kV. Lower-voltage substations, often at 35 kV or 10 kV, supply local distribution systems. These figures describe nominal system voltages, not necessarily the exact readings seen on every instrument.

The full picture is more varied. Some areas use 66 kV networks, and major transmission corridors may operate at 1,000 kV AC. China also uses high-voltage direct-current links, including ±500 kV and ±800 kV schemes; these are not interchangeable with AC voltage labels. Important distinctions. Transformer nameplates, grid planning documents, and equipment specifications can show different voltage values because rated equipment voltage may differ from the network’s nominal level. Regional demand, terrain, and the connection point also shape a project’s design.

This overview introduces the common levels and their roles, rather than treating one list as universal. Standards and project requirements can change, so engineers verify the applicable national standards and local grid-company documents before selecting equipment. A chart is useful, but it cannot replace that check. Even a simple 110/10 kV substation involves protection settings, insulation coordination, and site conditions that deserve careful review. The labels look tidy; real systems are less tidy.

China’s Power Grid Structure and Substation Voltage Classes

What Are the Standard Substation Voltage Levels in China?

China’s power grid links generating stations to consumers through several voltage tiers. Large power plants feed high-voltage transmission networks, which carry electricity across long distances. Regional substations then lower voltage for cities, factories, and local distribution. The structure is layered. It is not uniform.

Common AC substation classes include 1,000 kV, 500 kV, 220 kV, 110 kV, 35 kV, and 10 kV. The 1,000 kV and 500 kV levels support bulk transmission, while 220 kV and 110 kV commonly serve regional networks. Lower levels connect industrial users and distribution systems. Some areas also use 66 kV, but it is not a standard choice everywhere. China also operates high-voltage DC links, including ±800 kV projects; these should not be confused with AC substation voltage classes. Actual configurations vary with local demand, network design, and planning history. A voltage label alone tells only part of the story.

Tips: When reviewing a substation, check the transformer nameplate and the voltage shown for each bus. A 110/10 kV transformer, for example, connects two different grid tiers. Local practice can differ. Verify the site data.

Common Transmission and Subtransmission Voltage Levels

China’s transmission network uses several voltage tiers, each suited to a different distance and power flow. The national standard GB/T 156-2017 includes 1,000, 750, 500, 330, and 220 kV nominal AC levels. The 1,000-kV system carries bulk power across long distances. The 500- and 220-kV networks connect major generation areas, regional grids, and large substations.

Subtransmission commonly uses 110, 66, and 35 kV, though local practice varies. A 110-kV line may feed a city-area substation, while 35 kV can serve industrial loads or smaller towns. The 66-kV level remains in some regional networks, but it is not universal. These distinctions can look untidy on a map. They reflect different grid histories and local demand.

Scale matters. The China Electricity Council’s 2023 industry statistics reported about 894,000 km of transmission lines rated 220 kV and above. That figure shows how extensive the high-voltage backbone has become, but it excludes lower-voltage subtransmission circuits. China also operates ±800-kV direct-current links for long-distance transfers; that figure describes pole voltage, not an AC substation level. For equipment selection, engineers must check the rated voltage, insulation requirements, and the grid operator’s connection rules—not just the nearest familiar number.

Distribution Voltage Levels at Urban and Rural Substations

What Are the Standard Substation Voltage Levels in China?
Distribution Voltage Levels at Urban and Rural Substations

In Chinese cities, substations commonly step incoming 110 kV or 220 kV power down to 10 kV for local distribution. Some networks also use 20 kV, depending on regional planning and equipment. Nearby distribution transformers then supply buildings at 380 V three-phase or 220 V single-phase. A street-side transformer may serve several apartment blocks, shops, or smaller facilities.

Rural networks often use 10 kV feeders too, but long distances and scattered villages can change the design. In some areas, 35 kV lines carry power over longer routes before substations reduce it to 10 kV. The exact arrangement varies with terrain, load, and local grid plans. A remote village is not automatically supplied at a different voltage; its feeder length and transformer locations matter. This distinction is easy to overlook during site planning.

Tips: Check the local utility’s connection requirements before selecting equipment. Confirm both the incoming feeder voltage and the required low-voltage supply. Small details matter. A 220 V household supply is not the same as a 380 V three-phase service.

How Substations Transform Voltage Between Grid Levels

Factors That Determine Substation Voltage Selection

China’s common substation voltage levels include 10, 35, 110, 220, and 500 kV. Higher-capacity transmission also uses 750 kV and 1,000 kV AC, while ±500 kV and ±800 kV are used for some DC links. GB/T 156-2017 sets standard system voltages, but a standard value alone does not determine a project’s choice.

Load density is a major factor. A compact urban district may need 110 or 220 kV incoming supply to serve heavy demand through shorter local networks. Remote generation sites often need higher voltages to move large power flows over long distances. Higher voltage can reduce current and transmission losses, but it also requires costlier insulation, switchgear, and clearances. The China Electricity Council’s 2023 power-industry statistics report about 1.52 billion kW of installed renewable capacity. That figure illustrates why planners must consider where generation connects, not only where consumers live.

Reliability and future growth matter too. Engineers assess fault levels, network connections, transformer capacity, land limits, and the consequences of an outage. A substation beside a dense industrial park may need spare transformer capacity; a rural site may face longer feeder distances and different maintenance constraints. A tidy voltage table is useful, but it can hide these trade-offs. Forecasts also miss sometimes, so staged expansion may be more practical than building for every projected peak at once.