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Power System Load-Frequency Control and Automatics



URCh is an electronic relay series designed for power system frequency monitoring, automatic frequency load shedding and automatic generation control.

  • Three independent channels for frequency monitoring and three independent output relays with setting frequency and reaction/release time.
  • LED display for current frequency value indication.
  • Environment temperature withstand deviates from -40°C to +55°C range.

# Download the brochure. Protection and control devices.


The relay is a part of power system stability control and automation complex.
It provides the following functions:

  • Automatic frequency load shedding (ATLS);
  • Frequency-actuated auto-reclosing (FAR);
  • Automatic reserve generator start/stop (ARGS);
  • Operating permission on frequency reduction rate;
  • Frequency automatic network split automatics;
  • Frequency decrease/increase auto-limitation.


URCh-3M device can be used for hydraulic generators self-synchronized smooth start, for alarm signal on emerging water turbine rortor speed. Quantity rotor speed is controlled by monitoring the frequency of the generator of water turbine.

URCh-3M-S, URCh-3M-S-01, URCh-3M-S-02 modifications are unified frequency control relays.

URCh-3M-S-01 relay is intended for automatics schemes of hydraulic generators.

Relay URCh-3M-S-02 has additional input to control back-up power sources (generators or two separate electrical grids). Unload automation feature provides scheduled load group outage (or transfer to back-up power source) in order of their priority. Initial scheme auto-restoration on recovery. Other functions and technical characteristics conform to the functions and technical characteristics of relay URCh-3M-S.

Devices auxiliary and monitored power grid and quatized input "External reset" and also the relays have terminal block with switching contacts of output relays and the relay "Fault".

URCh modification produced in the same shell coating (HxWxD dimensions 85x140x136 mm; 0,9 kg weight).

Connection diagrams

URCh-3M-C, URCh-3M-C-01 connection diagram

URCh-3M-C, URCh-3M-C-01 connection diagram

URCh-3M-C-02 connection diagram

URCh-3M-C-02 connection diagram

# Download the brochure. Protection and control devices.