Abb manufacturers and supplies self-supplied relays to ensure complete protection of the installation without an auxiliary power supply. They are used in switchboards to provide protection of the medium voltage abb circuit breakers. There are two types of medium voltage circuit breaker protection device:
1 iec cb protection pr512 - this is available in three solutions.
-pr512/p [50-51 protections]
-pr512/p [50-51-50n-51n protections]
-pr512/pd [50-51-50n-51n protections with dialogue].
2 pr521 - they are used as protection units for hd4/r - hd4/s and vd4/r - vd4/s medium voltage circuit breakers with rated voltage up to 24 kv.
