In one-and-a-half breaker and ring breaker arrangements, the T-zone exists between two breakers and line/transformer feeders. The PCS-924 is designed to provide current differential protection, sum-of-current protection and feeder end fault protection for the T-zone. It provides three groups of CT input for direct connections to three terminal CTs. The disconnector is always installed in the feeder to facilitate the maintenance. The relay considers the different operating scenarios for the feeder with the disconnector. 3-terminal and 2-terminal current differential protections are automatically enabled/ disabled to meet different scenarios with closed or opened disconnector. The feeder end fault protection is enabled when the disconnector is opened. It is used to clear faults between CT and disconnector while keeping continuous operation of local breakers. The phase overcurrent protection employs the calculated sum current of two CTs. It can be applied for feeder energization and feeder backup protection.
The PCS-924 is compatible with IEC 61850 station bus and process bus applications. It supports IEC 61850-8-1 MMS, GOOSE and IEC 61850-9-2 Sampling Value. The RJ-45 faceplate port is provided for testing and setting, allowing for easier commissioning and maintenance.
Current differential protection (87S)
The switchover of 3-terminal and 2-terminal current differential protection can be automatically implemented according to the open/close state of feeder disconnector.
Two stage feeder end fault protection (50FLE)
This protection is only valid when the feeder disconnector is opened. It is used to clear the faults between CT and the opened disconnector. It will send a transfer trip command to remote end and keep the local breakers in service.
Sum overcurrent protection (50P)
Phase overcurrent protection is based on the summed current of two CTs. It can be used as the energizing protection or feeder backup protection.
Current drift auto adjustment
The relay continually and automatically traces the voltage and current drifts and adjusts the zero point to acquire accurate measurements.
CT circuit supervision (CTS)
Auxiliary power supervision
Event recorder including 1024 disturbance records, 1024 binary events, 1024 supervision events and 1024 operating logs.
Disturbance recorder including 32 disturbance records with waveforms (The file format of disturbance recorder is compatible with international COMTRADE file.
Clock synchronization using IRIG-B, SNTP, PPS (Pulse-Per- Second) and PPM (Pulse-Per-Minute)
Up to four 10Base-T/100Base-TX copper Ethernet ports using IEC 61850, DNP3.0 or IEC 60870-5-103 over TCP/IP
Up to two 100Base-FX optical Ethernet ports using IEC 61850, DNP3.0 or IEC 60870-5-103 over TCP/IP ( Sharing two copper Ethernet ports)
Two RS-485 serial ports using IEC 60870-5-103
One RS-485 serial port for clock synchronization
Optional Sampling value and GOOSE communication module with six optical Ethernet ports using IEC 61850-9-2 and IEC 61850-8-1 GOOSE.
HMI interface with large-size LCD and 9-button keypad on the front panel
One front RJ-45 port for testing and setting
One RS-232 or RS-485 rear port for printer
Language selection – English + selected language
Assistant software - PCS-Explorer