High impedance protection
The 7SR23 DAD is a numeric high impedance circulating current relay that has four current inputs, it is used as a unit protection to detect phase and earth faults.
![High impedance protection – Reyrolle 7SR23 High impedance protection – Reyrolle 7SR23](https://assets.new.siemens.com/siemens/assets/api/uuid:cecfeeb3-bd53-4a08-82bc-820a94562b93/width:100/quality:low/High-Impedance-Protection-Reyrolle-DAD-7SR23-original.png)
The 7SR23 DAD is a numeric high impedance circulating current relay that has four current inputs, it is used as a unit protection to detect phase and earth faults.