Pilot wire current differential feeder protection
The 7PG21 is a three-phase unit differential protection used to detect in zone phase and earth faults. The relay is applied to the overhead line and underground cable circuits as well as shorter circuits such as interconnectors.
![Pilot wire current differential feeder protection – Reyrolle 7PG21 Pilot wire current differential feeder protection – Reyrolle 7PG21](https://assets.new.siemens.com/siemens/assets/api/uuid:f051e322-5e57-44ee-8d66-13d419058d2f/width:100/quality:low/Pilot-wire-current-differential-feeder-protection-Reyrolle-7PG21.png)
The 7PG21 is a three-phase unit differential protection used to detect in zone phase and earth faults. The relay is applied to the overhead line and underground cable circuits as well as shorter circuits such as interconnectors.