A factory-assembled step-up package for photovoltaic plants — inverter collection, step-up transformer, MV switchgear and the grid-connection cabinet delivered as one unit.
Photovoltaic projects move fast and are measured against the grid connection date. Supplying the step-up package as one pre-tested unit removes a long list of interfaces — between the collection system, the transformer, the switchgear and the grid-connection cabinet — and those interfaces are where schedule and commissioning problems usually appear.
A solar step-up substation is the standard arrangement for a photovoltaic plant with a medium-voltage grid connection. The inverter outputs at 0.4 kV, the collection system raises that to 10 kV or 35 kV through a step-up transformer, and the MV switchgear collects the feeder circuits and connects them to the grid through the grid-connection cabinet. Delivering these elements as one pre-assembled, pre-tested package means the civil work on site reduces to a foundation and the incoming and outgoing cables.
Power arrives from the inverter blocks into the MV collection section, passes through the step-up transformer and appears at 10 kV or 35 kV on the grid side. The MV switchgear then provides the feeder connection, the isolation and the metering point, while the grid-connection cabinet carries the protection, the metering and the dispatch communication required by the grid operator. The whole package is tested as a system in the workshop, so site commissioning reduces to switching and setting verification.
| Parameter | Typical value |
|---|---|
| Collection voltage | 0.4 kV from the inverter blocks |
| Step-up voltage | 0.4 kV / 10 kV, 0.4 kV / 35 kV, or 10 kV / 35 kV as required by the grid |
| Step-up transformer | Oil-immersed S13 / S20 / S22 class, or dry-type SCB class where the site requires it |
| Transformer rating | 1000 / 1250 / 1600 / 2000 / 2500 / 3150 kVA and above, sized to the plant capacity |
| MV switchgear | KYN28A-12 withdrawable cabinet, or ring main unit arrangement where the grid requires it |
| Grid-connection cabinet | 10 kV with anti-islanding protection, 0.2S class metering and dispatch communication |
| Reactive compensation | Automatic capacitor bank in the LV or MV section, sized to the plant's reactive demand |
| Enclosure | Outdoor prefabricated enclosure, IP33 standard, IP44 on request |
| Ambient temperature | -25 °C to +40 °C; altitude up to 2000 m |
| Documentation | Single-line diagram, protection setting list, routine factory test reports and commissioning records |
| Compliance | GB/T 17467-2020, GB/T 3906-2020, GB/T 19964 (PV power station design), local grid code for the protection scheme |
Begin with the grid connection approval — it fixes the connection voltage, the protection scheme, the metering class and the dispatch communication, and no equipment selection should start before that document exists. Then work backwards from the plant capacity to the number of inverter feeders, the collection current and the step-up transformer rating. Finally, check the reactive and export limitation requirements, because a plant with a restrictive export limit often needs a different compensation arrangement and a specific protection interface with the inverter control system.
It is the assembly that raises the 0.4 kV output of the inverters to the plant's medium voltage level and connects the plant to the grid. It normally combines a step-up transformer, MV collection switchgear and a grid-connection cabinet in one prefabricated package.
0.4 kV to 10 kV and 0.4 kV to 35 kV are the usual arrangements for PV plants, and 10 kV to 35 kV is used where the plant already has an internal MV collection level. The ratio is confirmed against the grid connection approval.
Overcurrent, instantaneous and zero-sequence protection, anti-islanding protection per the applicable grid code, a 0.2S class metering unit and the dispatch communication interface for remote telemetry, remote signalling, remote control and remote adjustment.
Yes. The quotation and the technical package include the single-line diagram, the protection setting list and the routine factory test reports, plus commissioning records for the connection process.
Yes. An automatic capacitor bank can be included in the LV or MV section, sized against the plant's reactive demand and the grid's power factor requirement.
15 days for customized plant configurations, counted from deposit plus confirmed technical agreement plus approved drawing. Standard 10 kV cabinets and standard transformer ratings are available within the standard 10-day window.
Send us the rated voltage, rated current or capacity, quantity and destination country, plus any single-line diagram. We reply with a configuration proposal and a quotation — usually within 24 hours of receiving complete technical information.
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