Abb is well known for manufacturing a wide range of multi-purpose protection relays that are over current and earth-fault relay. The lists of models are as follows with their distinct features:
1 spaj 110 c - earth-fault relay for selective earth-fault protection, either primary or back-up, in solidly or low-resistance earthed systems
2 spaj 115 c - combined restricted earth-fault & residual earth-fault relay for power generator, motor and transformer protection
3 spaj 135 c - combined phase over current & earth-fault relay for time & current graded over current & earth-fault protection in distribution networks
4 spaj 141 c - combined over current & earth-fault relay for the selective protection of radial feeders in solidly, resistance or impedance earthed systems
5 spaj 144 c - combined phase & neutral over current relay for selective short-circuit & time over current protection of radial feeders in distribution networks
6 spaj 111 c - sensitive earth-fault relay for neutral current measuring, generator interterm fault, capacitor bank unbalance & rotor earth-fault protection
7 spaj 131 c - over current relay for two-stage phase over current protection of distribution feeders, large lv motors, hv motors, generators & power transformers
8 spaj 140 c - combined over current & earth-fault relay for the selective protection of radial feeders in solidly, resistance or impedance earthed systems
9 spaj 142 c- combined over current & earth-fault relay for the selective protection of radial feeders in solidly, resistance or impedance earthed systems
