Transformer protection relay
IMPR-1 Orion Italia

The Current Measurement and Protection Unit (IMPR-1) has been designed to measure the line and ground RMS currents and supply RMS voltages under normal conditions or under disturbances. The voltage and current signals are sensed throughout potential transformers (PT) and current transformers (CT) from each line. This information is internally processed by the microprocessor, to take the current protection actions defined under ANSI, IAC or IEC standard. Additionally the operational conditions of the breaker or disconnector are also signalized. The different functions provided by the IMPR-1 may be classified into the following groups:

Applications:
- Primary and backup protection for power plants, utility and industrial distribution systems.
- Protection of transformers, overhead lines, cables and generators.
- Permits the opening of the switch/disconnector within the limits of its capacity, those identifying the excess (e.g. straight short-circuits), leaving the circuit interruption to the back-up fuses.