MELPRO-D, multifunction digital relays for feeder, motor and transformer protection 6–35 kV
MELPRO-D is a series of compact multifunction digital protection relays for distribution networks that the Japanese classification places in high and extra-high voltage. The range covers feeder and motor protection relays and transformer differential relays with restraint. The relays communicate with SCADA systems over IEC 61850 or Modbus.
- Purpose
- protection of feeders and motors, transformer differential protection
- Communication
- IEC 61850 (2 optical ports, HSR/PRP), Modbus RS485
- Waveform recorder
- up to 5 records, 24 samples per cycle
- Setting groups
- 2
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
MELPRO-D relays contain the elements needed to protect lines, transformers and motors of the distribution network and work in power distribution automation systems. In our terminology these are MV networks and distribution substations. The transformer differential relay has restraint, which reduces the risk of false operation from unbalance currents during external short circuits. Overcurrent protection is set up with multi-step time selectivity. Two setting groups make it possible to switch to a test mode or to account for different load modes.
The circuit breaker is closed and opened from the relay panel or remotely. For communication with SCADA systems there are IEC 61850 over Ethernet and Modbus over RS485. For IEC 61850, 2 optical ports are provided. IEC 61850 exchange runs over optical fibre, so the communication line is insensitive to electromagnetic interference in the switchgear. If both are used, HSR (High-availability Seamless Redundancy) or PRP (Parallel Redundancy Protocol) redundancy is selected through the user interface, and the loss of one channel does not interrupt exchange with the control level.
The relay stores up to 5 fault waveform records at 24 samples per cycle, which are analysed with the PC Tool program. The setting software changes settings, shows status, controls the circuit breaker, reads the sequence of events log (SOE) and the disturbance fault recorder (DFR) data. Built-in programmable logic (PLC) adapts the algorithms to the user's tasks, for example cell interlocking or automation.
A vacuum fluorescent display (VFD) is easier to read than an LCD, including in a poorly lit switchgear room. Self-diagnostics monitor the main hardware units and issue a signal on failure. The optional 2-out-of-3 scheme preserves protection even when one of three relays has failed, so it is chosen for critical bays.
The panel cut-out size matches the previous version of MELPRO-D, so relays are replaced without panel modification. In terms of EMC and protection functional elements the relays comply with the IEC 60255 series. At the design stage the suitable relay type is selected for each bay, that is feeder, motor or transformer differential, and two setting groups are defined for operating modes.
Technical specifications
| Purpose | protection of feeders and motors, transformer differential protection |
|---|---|
| Communication | IEC 61850 (2 optical ports, HSR/PRP), Modbus RS485 |
| Waveform recorder | up to 5 records, 24 samples per cycle |
| Setting groups | 2 |
| Display | vacuum fluorescent display (VFD) |
| Logic | built-in programmable logic (PLC) |
| Redundancy | 2-out-of-3 option |
| Standard | IEC 60255 series |
Request a price and lead time
MELPRO-D, multifunction digital relays for feeder, motor and transformer protection 6–35 kV. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Customs codes
| UKTZED (Ukraine) | 8536 49 00 00 |
|---|---|
| HS, 6 digits | 8536 49 |
| CN (EU) | 8536 49 00 |
| HTSUS (USA) | 8536 49 00 85 |
| China customs tariff | 8536 49 00 00 |
Codes are for reference: the final code is determined at declaration for the specific model.
Questions and answers
Which communication protocols does MELPRO-D support?
IEC 61850 over Ethernet with 2 optical ports and HSR or PRP redundancy, and also Modbus over RS485.
How many fault records does the relay store?
Up to 5 waveform records at 24 samples per cycle. They are analysed with the PC Tool program.
Which standards does the MELPRO-D series comply with?
The relays comply with the IEC 60255 series for EMC and protection functional elements. The optional 2-out-of-3 scheme preserves protection if one relay fails.
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