over-voltage protection relay / under-voltage / over-current / over-frequency



  • Measured/monitored value:

    over-voltage, under-voltage, over-current, over-frequency, under-frequency

  • Other characteristics:

    digital, programmable, configurable, three-phase, multifunction, adjustable, IEC


Transformer Protection Relay
Protect and monitor most three- and four-winding transformers and terminals with the versatile SEL-787 Transformer Protection Relay platform. Select SEL-787-3E/-3S models, and apply three-phase current and voltage inputs with options for either a single-phase restricted earth fault (REF) input or a single-phase voltage input for comprehensive transformer protection. Select the SEL-787-4X for current-based, four-winding differential protection. Benefits include advanced automation and flexibility; single or dual copper or fiber Ethernet communications ports; asset management data; and easy retrofit of most electromechanical relays.