KR-3400AIntroduction to Series Main Transformer Protection and Measurement Devices

The KR-3000A series main transformer protection and measurement device is a complete set of protection devices suitable for transformers with three or more turns and voltage levels of 110KV and above. The complete set of protection consists of differential protection, backup protection, and non electricity protection. For a 110KV transformer, generally KR-3420A (differential protection)+KR-3410A (high-voltage side backup protection measurement and control)+KR-3430A (low-voltage side backup protection measurement and control)+KR3440A (non electricity protection+operation circuit) can be used to form all the protection and measurement functions of the transformer. Add a set of backup protection and measurement device on the medium voltage side to the main transformer with a medium voltage system, with the same model as KR-3430A.

Main functions

●Differential quick break protection

●Ratio differential protection for second harmonic braking

●CT disconnection, distributed fault recording

●Overcurrent protection on the medium and low voltage sides

●3-channel remote signal input acquisition, remote signal displacement, and accident remote signal

●2-channel remote control signal output points

●Device alarm, protective action

KR-3420AWiring schematic diagram of differential protection measurement and control device for three coil transformer

Note:

1. This diagram is designed with a three circle variation

2. If bridge current needs to be introduced, introduce the bridge switch current into the bridge side current

3. The current direction on both sides is directed towards the transformer, and the same terminal is connected according to the diagram