HighPROTEC MCDGV4 differential protection of generators and generator-transformer units
HighPROTEC MCDGV4 is a digital differential protection relay for medium and large generators, in whose zone a step-up transformer can be included. The terminal combines longitudinal and earth differential protection with a full generator package and grid connection functions. It is installed on generators of power plants, gas engine and diesel sets and small hydropower plants.
- Application
- medium and large generators, generator-transformer unit
- Main protections
- longitudinal and earth differential (87G/87GN)
- Generator functions
- loss of excitation (40), out-of-step/pole slipping (78), inadvertent energization (50/27), 100 % stator earth fault by 3rd harmonic, V/f overexcitation, reverse power, voltage-restrained overcurrent 51V/51C
- Distance protection
- 2 stages, power swing blocking
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
MCDGV4 belongs to the HighPROTEC line from the manufacturer and covers the protection of medium and large generators. The protection zone can be extended to a step-up transformer, and then the relay works as a generator-transformer unit protection. The basis of the terminal is phase longitudinal differential protection and differential earth fault protection (87G/87GN), which detect internal faults of the generator or of the whole unit. Besides station generators, the relay is used on generator-transformer units of industrial power plants.
The generator package is assembled in one device. Two V/f overexcitation protection stages are needed, for example, for a unit transformer during run-up. Two more stages monitor loss or reduction of excitation (ANSI 40). Stator overload is tracked by a thermal model. Overcurrent protection has six stages with voltage restraint or voltage control (51V/51C). There are several reverse power stages for the prime mover, negative sequence protection, two distance protection stages and out-of-step protection (pole slipping, ANSI 78) with power swing blocking. Earth faults over 100 % of the stator winding are detected by the third harmonic. The set is complemented by multi-stage overvoltage and undervoltage protection with an adjustable reset ratio, wattmetric earth fault protection, voltage asymmetry protection and protection against inadvertent energization of a stopped generator (50/27). Temperature can be monitored through an external URTD unit for 12 sensors.
For operation in parallel with the grid there are FRT (LVRT) profiles with coordination with auto-reclosing, Q-U protection by reactive power at reduced voltage, automatic reconnection, six frequency protection stages (f<, f>, df/dt, vector jump), transfer of the trip command to the circuit breaker and synchronism check. The terminal controls up to six switching devices and counts circuit breaker wear.
The hardware is built on a dual-core processor. The Modbus, Profibus, DNP3.0, IEC 61850, IEC 60870-5-103 and IEC 60870-5-104 protocols support individual data point assignment, time is synchronized via SNTP and IRIG-B, and cybersecurity functions are included. Non-volatile recorders store waveforms for 120 s, 20 faults, 300 events and a trend of 4000 records. Commissioning is speeded up by a built-in fault simulator and a plausibility check of settings. The Smart view software, waveform analysis tools and the full set of functions are supplied at no extra charge under the all-inclusive concept.
Technical specifications
| Application | medium and large generators, generator-transformer unit |
|---|---|
| Main protections | longitudinal and earth differential (87G/87GN) |
| Generator functions | loss of excitation (40), out-of-step/pole slipping (78), inadvertent energization (50/27), 100 % stator earth fault by 3rd harmonic, V/f overexcitation, reverse power, voltage-restrained overcurrent 51V/51C |
| Distance protection | 2 stages, power swing blocking |
| Grid connection | FRT/LVRT, Q-U protection, automatic reconnection, synchronism check |
| Temperature | external URTD unit, 12 sensors (option) |
| Switching devices | up to 6 |
| Recorders | 120 s / 20 faults / 300 events / 4000 trends |
Request a price and lead time
HighPROTEC MCDGV4 differential protection of generators and generator-transformer units. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Customs codes
| UKTZED (Ukraine) | 8537 10 98 00 |
|---|---|
| HS, 6 digits | 8537 10 |
| CN (EU) | 8537 10 98 |
| HTSUS (USA) | 8537 10 91 70 |
| China customs tariff | 8537 10 90 90 |
Codes are for reference: the final code is determined at declaration for the specific model.
Questions and answers
Can a unit transformer be included in the MCDGV4 protection zone?
Yes, a step-up transformer is included in the differential protection zone, and the relay works as a generator-transformer unit protection. Two V/f overexcitation protection stages protect the transformer during run-up.
How does MCDGV4 protect the stator winding against earth faults?
The protection covers 100 % of the stator winding by the third harmonic. It is complemented by 87GN earth differential protection and wattmetric earth fault protection.
What communication protocols does MCDGV4 support?
Modbus, Profibus, DNP3.0, IEC 61850, IEC 60870-5-103 and IEC 60870-5-104 are available. Time is synchronized via SNTP and IRIG-B.
Similar equipment from other manufacturers
