- High-Impedance Differential Protection
Provide high-speed, economical bus protection with a three-phase, high-impedance differential bus zone. 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 (MOVs) are connected in parallel with the high-impedance element to clamp secondary peak voltage to less than 2 kV. Make use of simple settings and dedicated same-ratio CTs to create a cost-effective and easily expandable bus protection solution.
- Overcurrent Protection
The SEL-587Z features separate phase, neutral, and negative-sequence overcurrent elements, including instantaneous, definite-time, and inverse time-overcurrent elements, for backup overcurrent protection.
- Breaker Failure/Fault-Cleared Detection
Detect breaker failure and bus fault status by using an overcurrent element series with the high-impedance element.
- Protection and Control Logic
SELogic control equations with SELogic variables and timers facilitate traditional or advanced protection schemes.
- Monitoring and Reporting
Oscillographic event reports (up to ten 15-cycle reports) and metering functions eliminate or reduce external recorder and metering requirements. The SER stores the latest 512 entries in nonvolatile memory.
- Serial Data Communications
Use the front and rear serial ports for communicating with ASCII terminals, a local human-machine interface (HMI), SCADA, or distributed control systems (DCSs). 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 for the Modbus RTU outstation protocol.