Product Overview

As the third line of defense in power systems, the NARI Relays PCS-994 Series Frequency and Voltage Emergency Control Device provides under-frequency, under-voltage, over-frequency and over-voltage control functions. It is mainly used for under-frequency load shedding and disconnection, under-voltage load shedding and disconnection, over-frequency generator tripping and disconnection, and over-voltage disconnection. The device simultaneously measures voltages of multiple bus sections in the same system, and the trip matrix for each round can be flexibly configured. It fully supports digital substation functions, including IEC 61850-9-2 sampled value transmission protocol and IEC 61850 protocol with real-time GOOSE functionality.

Product Functions

Control Functions

Under-frequency load shedding and disconnection

Under-voltage load shedding and disconnection

Over-frequency generator tripping and disconnection

Over-voltage disconnection

Comprehensive criteria to prevent system frequency oscillation caused by over-shedding

Round-by-round automatic restoration of power supply after under-frequency load shedding

Adaptive blocking of under-voltage load shedding during short-circuit faults

Auxiliary Functions

Online monitoring of hardware and circuits

Synchronization via minute pulse, second pulse, and IRIG-B

128 event reports and 32 fault recording reports

Diverse communication solutions supporting power industry standards IEC 60870-5-103 and IEC 61850

User-friendly human-machine interface: convenient commissioning software, powerful waveform analysis tools, etc.