HV Systems

Numerical Relay [Digital Relay]


The digital protective relay is a protective relay that uses a microprocessor to analyze power system voltages, currents or other process quantities A big difference between conventional electromechanical and static relays is how the relays are wired. Electromechanical and static relays have fixed wiring and the setting is manual.

Numeric relays, on the other hand, are programmable relays where the characteristics and behavior can be programmed. Most numerical relays are also multifunctional.

Salient Features

  • Conforms to IEC 60255 / IS 3231
  • Phase and Earth Fault poles have four protection elements per Relay
  • Wide setting ranges and characteristic selection NI, VI, EI, LTI, 3s, 1.3s, 0.6s & DTL for Phase & Earth Fault
  • Programmable 7 Digital I/O
  • Last 999 fault events with time stamp, type & fault current magnitude value
  • Self monitoring facility (watchdog)
  • Circuit Breaker Failure Protection
  • Multi-Shot Auto Reclose Function
  • Inbuilt Trip Circuit Supervision
  • 1A or 5A CT inputs in a Relay (User/Site Selectable)
  • NDR input is 110V AC 3 phase from PT (optional)
  • SCADA Compatibility (RS485 & USB Port)
  • Latched trip (86)
  • User-friendly settings and indications
  • Draw-out / Fixed type