PRS-778 provides fast and selective protection, monitoring and control for two and three-winding transformers, auto transformers, step-up transformers and generator-transformer block units, phase shifting transformers, special railway transformers, shunt reactors, etc. The relay can operate correctly over a wide frequency range in order to accommodate power system frequency variations during disturbances and generator start-up and shut-down.
This relay can sample the analog values from the traditional instrument transformers, or receive the sampled values from the electronic current and voltage transformers (via a merging unit). The binary inputs and outputs of this relay can be configured according to the demands of a practical engineering through the PRS IED Studio configuration tool auxiliary software, which can meet some special requirements of protection and control functions.
This relay can fully support the IEC61850 communication protocol and GOOSE function, and can completely meet the demands of a modern digitalize substation.
It provides fast, selective primary and backup protection for various transformers from 10kV to 1000kV, supporting modern standards like IEC61850 and GOOSE.
Innovatively integrates six functions—protection, measurement, control, remote signaling, merging unit, and remote module—into one device, simplifying architecture and enhancing reliability.
Built on a 32-bit high-performance dual-core processor with modular hardware design, allowing flexible configuration and interchangeability of non-core modules for easy expansion and maintenance.
Features a high-quality LCD display, navigation menu keys, and configurable function keys for real-time monitoring of status, events, measurements, and modifying protection settings with ease.
Standard | IEC60225-1: 2009 |
Mounting Way | Flush mounted |
Merchanical size (width×high×deepth) | 1/2 19” Case: 260mm*266 mm *217.7 mm 1/1 19” Case:482.6mm*266 mm *217.7 mm |
Housing material | Metallic plates, parts and screws: Steel Plastic parts: Polycarbonate |
Protection class | Front side:IP40 (IP52 with seal strip) Rear side, connection terminals: IP20 Other Sides: IP40 |
Communication Ports | 3 Ethernet network 2 RS-485 serial ports |
Communication Protocol | IEC61850, IEC60870-5-103, DNP3.0 or ModBus. |
Time Synchronization | SNTP, lEEE 1588, pulse per second (PPS) and IRlG-B |
Function | Transformer differential protection 87T Winding Differential Protection 87W Mho Impedance protection 21M Quadrilateral Impedance protection 21Q Power swing detection 68PS Four stage directional overcurrent protection 67P Three-phase thermal overload protection 49 Earth Fault protection 51G Restricted Earth Fault protection 64REF Non-directional Instantaneous earth fault protection 50/51N Breaker Failure Protection 50BF Three stage residual overvoltage protection 59N Two stage three-phase overvoltage protection 59P Two stage three-phase undervoltage protection 27P Overexcitation protection 24 Overfrequency protection 81O Underfrequency protection 81U Rate-of-change frequency protection 81R Reactor differential protection 87R Reactor zero-sequence differential protection 87N Reactor interturn Protection 21IT Current circuit supervision CTS Fuse failure supervision VTS |
