Patent ID: 7359182

Claim:
A plug-in unit assembly comprising instrument transformers, including a case assembly comprising a connector assembly, and a plug-in unit comprising at least one instrument transformer and configured to be connected to the case assembly, whereby, when the plug-in unit is being inserted into the case assembly, said at least one instrument transformer is configured to be connected to the connector assembly and is selected from a set comprising current transformers and voltage transformers, wherein the set from which said at least one instrument transformer of the plug-in unit is selected is composed of instrument transformers coded in such a manner that the codings of the current transformers and the voltage transformers are different, and in that the connector assembly is capable of identifying the type of said at least one instrument transformer based on its coding when the plug-in unit is being connected to the case assembly, and wherein the assembly is arranged such that the connection of the plug-in unit for the first time to the case assembly achieves changes in the connector assembly which are based on a type identification carried out based on the coding of the instrument transformers, and which, when the plug-in unit connected to the case assembly is being detached from the case assembly, cause the connector assembly to short the current circuit corresponding to each current transformer and to leave open the voltage circuit corresponding to each voltage transformer.