User Manual

Description
2.3 Protection system
3WA Air Circuit Breakers
Equipment Manual, 05/2021, 92310000002-03
59
(1)
Restricted zone of protection
(2)
Unrestricted zone of protection
Current transformer configurations
Depending on the network topology of the power distribution system, several current
transformers are required for the detection of ground-fault currents on the infeed side. In
practice, current transformers of class TPS (former designation class X) according to
IEC 60044-6 are used in a transformer combination. If only one current transformer is used in
the neutral point of the transformer, the ground-fault currents of the outgoing feeders are
also acquired via this transformer.