Single function protection relays (SFPRs) are used for time-graded current (over current or short circuit), voltage (over voltage, under voltage, voltage unbalance) and frequency protection applications. Single function or compact relays are used in low-voltage applications. They are DIN rail-mountable and are easy to install, operate and commission. The wide-range power supply for AC and DC make these relays universal. Compact relays can be single or three phase relays.
Single function protection relays use MCU with an internal ADC for measuring the electrical parameter. A seven segments LED or character LCD is provided to display measured parameters. LEDs are provided for quick indication of the load status and other system functionalities. One or two relay outputs are provided for disconnecting the load during fault conditions. The parameter settings are configured using keys, rotary switches or potentiometers provided on the front panel. An RS-485 interface with MODBUS protocol is provided for networking.