Month: June 2026

Measuring principle

The relay measures the leakage or a short circuit from one or more of the phases to earth.

In order to obtain a short response time on a fault condition, the measurement is based

on peak values.

The earth fault current protection is for example obtained by connecting an external current

transformer in the star point of the protected voltage source.

In order to prevent malfunction due to 3rd harmonic, the RMC-142D is equipped with

a special filter cutting off frequencies higher than 50/60 Hz.

The set point values are set on the front of the relay by means of potentiometers.

If exceeded, a fault signal is generated, and the associated yellow LED is lit.

Timer functions

When the set point is exceeded, its timer starts and will run as long as the fault condition prevails.

If the fault disappears, the timer is reset. When the timer expires, the contact is activated

and the associated red LED is lit.

Relay outputs

The RMC-142D is provided with two outputs with maximum contacts either normally

energised or normally de-energised.

The contact may be set to open or close on activation.

Normally energised contact

Recommended for warning and alarm purposes.

In case of an auxiliary supply dropout, the contact is immediately activated.

Application

The protective stator earth fault relay type RMC-142D forms part of a complete

DEIF series of relays for protection and control of generators. The RMC-142D

is primarily designed for land-based installations. Also available are short circuit

relays (RMC-111D), combined short circuit and over-current relays (RMC-122D)

and double over-current relays (RMC-132D).

The RMC-142D is CE-marked and is applied for protection of voltage sources and

load networks against earth fault in a solid earthing or a low-resistance earthing system.

Normally de-energised contact

Recommended for installations for regulating and control purposes.

An auxiliary supply failure will not result in an unwanted activation of the contact.

Latch circuit

The contact can be locked in its warning position, even if the earth faulty current

(leakage current) returns to normal (add “L” to contact type in order specifications,

if this is required). The latch circuit is reset by disconnecting the auxiliary supply.

Hysteresis

In order to avoid “chatter” on the relay contacts the contact functions are provided

with a hysteresis, that is a difference of 2 % of full scale between energising and

de-energising of the delay.

Power-up/power-down circuits

The RMC-142D is provided with a 200 ms power-up circuit, ensuring the correct function

of the relay on connection of the auxiliary voltage.

Features

• Earth fault protection at two levels

• Built-in filter for 3rd harmonic

• LED indication of fault condition

• Timer-controlled tripping

• LED indication for activated relay

• 35 mm DIN rail or base mountin

DEIF’s RMC-142D stator earth fault relay protects genset operators against electric

shock in case of earth faults in the generator’s stator.

The relay also protects against loss of excitation in case of earth fault in the stator.

The RMC-142D is part of DEIF’s complete range of relays for protection and control

of generators featuring a number of adjustable parameters.

Variants

RMC-111D

Short circuit

I>>: 100 to 400 %. <50 mS response time

RMC-121D

Short circuit

I>>: 100 to 400 %. 2 sets of contacts (parallel)

RMC-122D

Short circuit and over-current

I>>: 100 to 400 %, I>: 50 to 150 %

Combined functionality

RMC-131D

Differential current

I>>: 100 to 400 %. 2 sets of contacts (parallel).

M-Logic (Micro PLC)

This configuration tool is part of the PC utility software which is free of charge.

With this tool, it is possible to customise the application to your needs.

It is possible to dedicate specific functions or logical conditions to different inputs and outputs.

Setup®

Setup is easily done via a menu structure in the display (password-protected) or

via the USB PC connection and the Multiline 2 Windows-based PC utility software.

The utility software offers additional features such as monitoring of all relevant information

during commissioning, saving and downloading of settings and downloading of software updates.

Synchronisation

As an option, the GPU-3 Hydro can perform synchronisation of the generator.

After closing of the breaker the regulation is switched OFF, and the GPU-3 Hydro

will carry out all necessary protective functions.

Options

In order to perfectly match the product solution to specific applications, the functionality

of the GPU-3 Hydro can be equipped with a number of available options.

The options selected by the customer will be integrated in the standard GPU-3 Hydro,

hereby securing the same user interface unaffected by whether the application

needs a highly complex or a more basic genset controller.

Refer to the paragraph “Available options” for the options available.

Application

The Generator Protection Unit (GPU-3 Hydro) is a compact microprocessor-based 

protection unit containing all necessary functions for protection of a hydro turbine

driven synchronous/asynchronous generator. It contains all necessary

galvanically separated 3-phase measuring circuits.

The GPU-3 Hydro is well-suited for PLC-controlled systems, and the interfacing can

be done via digital and analogue I/Os or via serial communication.

Display unit

The display unit is separate and can be installed directly on the main unit or in the

front of the switchboard door (3 m display cable included). Up to two additional

displays can be installed within 200 m. The display unit shows all measured and

calculated values as well as alarms and data from the event log.

Self-test

The GPU-3 Hydro automatically carries out a cyclical self-test at start-up.

If any errors are found, they will be displayed in clear text in the display and 

indicated with a relay output (status output).

M-Logic (Micro PLC)

This configuration tool is part of the PC utility software which is free of charge.

With this tool, it is possible to customise the application to your needs.

It is possible to dedicate specific functions or logical conditions to different inputs and outputs.

Easy to operate and configure, DEIF’s Generator protection unit (GPU-3 hydro)

is an ideal controller for PLC-based hydro power systems.

The GPU-3 hydro offers comprehensive generator protection and synchronisation.

Serial communication enables easy interfacing with PLCs, SCADA systems and more,

and the unit features all necessary 3-phase measuring circuits and displays all

values and alarms on a quality LCD screen.

For start/stop and protection functionalities, add the GPU-3 hydro turbine control option,

a turbine interface card with separate power supply and independent microprocessor.

In cases of GPU-3 hydro main processor failure, the engine interface card will activate

its back- p mode to ensure uninterrupted turbine supervision and automatic turbine

shutdown in case of shutdown alarm.

With free software download and upgrade at www.deif. com, it is possible to customise

the application to suit your needs exactly: dedicate specific functions or logic conditions

to different inputs and outputs and tune all sequences according to your requirements.

Features

• Generator/busbar protection

• Synchronisation

• Multiple display units and operator panels possible

• Turbine protection with back-up on shut-down channels

• Turbine control and communication

Advanced communication features for system integration

MVR-200 relays are available with various communication standards like

IEC 60870-101/103/104 or IEC 61850 Ed. 2 which allow seamless into

your power management system.

Increase your system safety with Arc-flash protection

Arc-flash protection can be integrated into all MVR-200 relays with available hardware slots.

A variety of point and pressure sensors is available to reach perfect coverage of the

switchgear to clear any arc-flash before it causes any damage.

Features

• Programmable logic

• Fast and easy commissioning and service with front communication port and intuitive software

• Password-protected user levels

• Individual voltage and current harmonics up to 31st

• Redundant Ethernet with Modbus TCP

• RS-485 Modbus RTU communication

• IEC 60870-5-104/103/101 communication

• IEC 61850 communication (incl. HSR, PRP, PTP acc. IEEE 1588) and GOOSE

• On-site replaceable spare part modules

• Class 0.5 power and energy measurement (Class 0.2S optional)

• Conformal Coating available for all devices

• Marine type approval by major class societies

The MVR-200 series combines reliable protection, control and measuring

functionality in a single device for medium and high voltage applications.

The MVR-200 series offers reliable protection with powerful complementary

monitoring, measuring, communication and diagnostics functionality.

Comprehensive set of protection functions

The MVR-200 line of protection relays provides a comprehensive set of a total

of 16 different relays for your power management system.

With its flexible hardware design, it is easy to adjust the configuration to your specific needs.

Reliable hardware suitable for marine and land-based applications

MVR-200 relays come with marine approvals from all major classes.

Also land-based applications will benefit from the tested hardware which

will demonstrate utmost reliability required in e.g. critical power applications.

Advanced communication features for system integration

MVR-200 relays are available with various communication standards like

IEC 60870-101/103/104 or IEC 61850 Ed. 2 which allow seamless into

your power management system.

Increase your system safety with Arc-flash protection

Arc-flash protection can be integrated into all MVR-200 relays with available hardware slots.

A variety of point and pressure sensors is available to reach perfect coverage of the

switchgear to clear any arc-flash before it causes any damage.

DEIF’s differential current relay RMC-131D protects the generator against

short circuits and leakage currents in the windings of the generator.

The relay compares the differential current of each of the three phases,

providing an RMS measurement at sinusoidal currents.

In order to obtain a short response time on a fault condition,

the measurement is based on peak values.

The versatile units feature a number of adjustable parameters.

RMC-131D is part of DEIF’s complete range of relays for protection and

control of generators.

Variants

RMC-111D

Short circuit

I>>: 100 to 400 %. <50 mS response time

RMC-121D

Short circuit

I>>: 100 to 400 %. 2 sets of contacts (parallel)

RMC-122D

Short circuit and over-current

I>>: 100 to 400 %, I>: 50 to 150 %

Combined functionality

RMC-131D

Differential current

I>>: 100 to 400 %. 2 sets of contacts (parallel).

Features

• Differential current relay

• ANSI code 87

• Measurement of 3-phase currents

• Non-stabilised measurement

• LED indication of fault condition

• Timer-controlled tripping

• LED indication for activated relay

• Extra change-over relay contact for signalling

• 35 mm DIN rail or base mounting

The MDR-2 is a state-of-the-art combined differential protection and

short-circuit protection relay for generator protection against internal

short circuits (leaking currents).

Even in cases of fail tripping, the MDR-2 offers an adjustable tripping

characteristic function that compensates for unbalanced current

measurements, avoiding fail trippings altogether.

The MDR-2 gives you direct access to all settiangs and a chronological log

of up to 150 historical events/alarms. The unit’s integrated LCD screen displays

all measured and calculated values, eliminating the need for additional meters

or wiring, and facilitates fault-finding in connection with commissioning

identifying fault locations.

Available options include a block (generator + step-up transformer) protection

option and a short-circuit and over-current protection option.

Features

• Short response time (70 ms)

• 3-phase current detection on both generator sides

• Active adjustment of non-balanced current measurements

• Measuring accuracy 1 %

• Display indicator for all measurements

• DIN rail or base mounting with remote mountable display