Bus Protection

SEL-587Z High-Impedance Differential Relay

• High-impedance differential protection offers immunity against relay misoperation resulting from CT saturation. The SEL-587Z Relay uses internal 2000-ohm resistors to provide security against the effects of CT saturation for through faults. Internally mounted metal oxide varistors (MOV) are connected in parallel with the high-impedance element to clamp secondary peak voltage to less than 2 kV.
• Separate phase, neutral, and negative-sequence overcurrent elements, including instantaneous, definite-time, and inverse time-overcurrent elements for backup overcurrent protection.
• SELOGIC® control equations with SELOGIC variables and timers facilitate traditional or advanced protection schemes.
  
• Oscillographic event reports (up to ten 15-cycle reports) and metering functions eliminate or reduce external recorder and metering requirements. Sequential Events Recorder (SER) stores the latest 512 entries in nonvolatile memory.
  
• Use the front and rear serial ports for communicating with ASCII terminals, local HMI, SCADA, or DCS systems. As an ordering option, select an EIA-232 or EIA-485 rear serial port. Through settings, select and configure the ports for SEL ASCII and interleaved SEL Fast Binary messages, or Modbus® RTU Slave protocol.