Ring main units
Ring main unit configurations for incoming, outgoing and transformer circuits. Start with the circuit scheme, switching duties and protection requirements.
The circuit scheme comes first.
Key information for configuration review
- Rated voltage and configuration
- Short-circuit level
- Protection relay type
- Motorisation and SCADA
Start with the
right specification.
Use this selection reference to prepare your project brief.
Reference values are not a model datasheet. Availability, standards and test coverage require confirmation for the offered equipment.
Download project sheets ↓Selection reference +
| Rated voltage | 12, 24, 36 kV (for 11, 22, 33 kV systems) |
|---|---|
| Rated current | 630 A ring; 200 or 630 A tee-off |
| Short-time withstand | 16, 20 or 25 kA for 1 s or 3 s |
| Configurations | CCV, CCF, CCCV and extensible units (C = cable switch, V = vacuum breaker, F = fuse-switch) |
| Insulation | SF6 gas tank, or SF6-free (dry air or solid insulation) |
| Internal arc | IAC AFL or AFLR, 16 to 20 kA 1 s, where specified |
| Options | Motorised operation, remote terminal unit for SCADA, fault passage indicators |
Testing topics to confirm +
Confirm the applicable requirements, available reports and agreed test scope with the proposed manufacturer.
| Routine tests (every unit) | Dielectric test, main circuit resistance, mechanical operation, gas tightness for gas-insulated units |
|---|---|
| Type tests (per design) | Dielectric, temperature rise, short-time and peak withstand, making and breaking, internal arc, IP rating (IEC 62271-200) |
Project document package +
- Model-specific datasheet and approved drawings
- Applicable test reports and their coverage
- Inspection, packing and delivery requirements
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