Structure
The enclosure uses a double-layer composite panel with a honeycomb core: high mechanical strength, thermal insulation, and an outer skin available in stainless steel, aluminium alloy, aluminium-zinc coated steel or colour-coated steel. The roof is a removable double-layer structure, and the base frame accepts a roller for moving the transformer in and out.
Configurations
- Universal type: the standard arrangement for utility and industrial distribution.
- Roadside type: reduced footprint for street and pavement installation.
- Compact type: minimum plan area where space is restricted.
HV compartment
Load break switch and fuse combination with three-phase tripping when one fuse operates; or a vacuum circuit breaker (VS1, ZN63A, ZN28) with relays for larger transformers. Ring main and terminal configurations are available for cable-in, cable-out networks.
LV compartment
Main switch as an air circuit breaker or a moulded case circuit breaker with selective protection; outgoing ways in a new type of plug-in switch with small volume and short arc, up to 30 circuits; intelligent reactive power compensation with contactor or thyristor switching.
Standards
Prefabricated substations are designed to GB/T 17467 and IEC 62271-202, with the HV and LV compartments built to their own switchgear standards.
1. Transformer rating and type
State the rating in kVA, the vector group and whether an oil-immersed or dry-type transformer is required. Oil-immersed units suit outdoor utility installations; cast-resin dry-type units are used where fire load and indoor installation matter.
2. HV configuration
Radial or ring connection, cable or overhead entry, and the protection principle: load break switch with fuse up to about 800 kVA, or vacuum circuit breaker with relays above that.
3. LV configuration
Number of outgoing ways and their ratings, main breaker type, metering arrangement, compensation stages, and whether a communication interface is needed.
4. Enclosure and site conditions
Ambient temperature range, altitude, pollution level, snow and wind load, and the required outer finish. The standard enclosure is rated for an ambient of -25 °C to +40 °C and an altitude of up to 2000 m; outside these limits the design must be agreed.
What to send for a quotation
- Transformer rating, type and vector group
- HV single-line diagram and earthing arrangement
- LV load schedule and number of outgoing ways
- Site conditions: temperature, altitude, pollution, wind and snow
- Enclosure finish and colour, foundation or plinth details
- Automation and communication requirements
