Protection and control
Protection, control and relay panels
Panels that house the relays, control devices, metering and marshalling for a substation or switchboard, built to the scheme drawings.
- Built to
- the scheme drawingsthe drawings are the specification
- Contents
- relays, control, metering, marshalling
- Low voltage assembly standard
- IEC 61439 serieswhere the panel is a low voltage assembly
- Testing
- factory tests against the schemewitnessed where the specification requires
A protection and control panel is defined by its drawings. The schematic, the wiring diagrams and the equipment list are the specification, and a quotation is only as good as the drawings it is priced on.
The panels usually sit in a substation control room or beside the switchgear. They connect the relays to the instrument transformers and breakers, to the station supply and to the control system. Errors cost least when the factory test against the scheme finds them, before the panel ships.
What gets specified
| Parameter | Typical options | What decides it |
|---|---|---|
| Scheme drawings | Schematics, wiring diagrams, equipment list | The designer |
| Devices | Relays, meters, control switches, indicators | The scheme |
| Enclosure | Dimensions, IP rating, access front or rear | The room and the owner's standard |
| Auxiliary supply | DC and AC distribution within the panel | The station supply |
| Marshalling | Terminal arrangement and cable entry | The site cabling |
| Testing | Factory tests and witnessing | The specification |
Applicable standards
| Standard | What it covers |
|---|---|
| IEC 61439-1 and IEC 61439-2 | The panel as a low voltage assembly, where it is one |
| IEC 60255-1 | The relays mounted in it |
| IEC 60529 | The IP code of its enclosure |
Records a panel ships with
| Document | What it shows |
|---|---|
| Factory test record | Each function tested against the scheme drawings before shipment |
| As built drawings | The wiring as manufactured, marked up from the scheme, for commissioning |
What a control panel request needs
- Scheme drawings, or the single line diagram and a description of the functions
- Equipment list, or the relay and device preferences
- Enclosure dimensions, IP rating and access arrangement
- Auxiliary supply voltages
- Testing and witnessing requirements