ABB CM-UFD.M33M G99+coms Grid feeding relay with Modbus

Special Price £598.87 £499.06 Regular Price £831.77

ABB CM-UFD.M33M G99+coms Grid feeding relay with Modbus

CM-UFD.M33M 1SVR560731R3702 Grid feeding monitoring rel. 3c/o,L-L=0-550VAC,L-N=0-317VAC,ModbusRTU acc. to ENA EREC G98, ENA EREC G99

The CM-UFD.M33 with Modbus RTU is a multifunctional grid feeding monitoring relay. It provides different monitoring functions to detect over- and undervoltage (10-minutes average value, voltage increase and decrease protection) as well as any changes in grid frequency (frequency increase and decrease protection).
The device is connected between the distributed generation and the public grid in order to disconnect the distributed generation in case of problems (e.g. unstable grid), faults or maintenance on the grid. Additionaly, monitoring of ROCOF (rate of change of frequency) and vector shift can be configured.



Monitoring of voltage and frequency in single- and three-phase mains (2-wire, 3-wire or 4-wire AC systems)
Pre-settings in accordance with G98/1 and G99/1
Integrated management of redundancy function
Multiline, backlit LCD display
True RMS measuring principle
Over- and undervoltage, 10-minutes average value as well as over- and underfrequency monitoring
Two-level threshold settings for over-/undervoltage and over-/underfrequency
ROCOF (rate of change of frequency) monitoring and vector shift configurable
Interrupted neutral detection
All threshold values and tripping delays adjustable
Error memory for up to 99 entries (incl. cause of error, measured value, relative timestamp)
Test function
Password setting protection
3 control inputs, e.g. for feedback signal, remote trip
3 c/o (SPDT) contacts
Various certifications and approvals
(see overview, document no. 2CDC112249D0201)
Grid feeding monitoring for generating plants connected to distribution systems

More Information
Manufacturer ABB
Product Lead Time 2/3 Weeks
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The bridge between green energy and the power grid

CM-UFD grid feeding monitoring relays with ABB AbilityTM EDCS connectivity

G99 Relay Solar

Renewable energy sources – a challenge for power grids

ABB provides reliable stability


Weather conditions can mean generators need to feed several gigawatts of renewable power into the pubic grid within a short time. These sudden power increases can exceed the grid’s power control capabilities.

The rise of renewable energy sources

The rapid expansion of fluctuating renewable energy sources like wind turbines and solar power plants has had a dramatic effect on our power grid. Instead of a relatively small number of high capacity generating plants there are now thousands of small renewable power sources.

 Depending on weather conditions, several gigawatts of renewable power might be fed into the public grid within a short time.

Influence of fluctuating energy input

A sudden power rise, for example on an especially windy day, might exceed the grid power control capabilities. To stabilize the grid, renewable power plants must be disconnected so that the energy generated and the energy consumed can be balanced.

 If both are not in equilibrium, the frequency increases or decreases in the public network, increasing the risk of a blackout.

Grid Feed Protection

The solution for stable power grids

Controlled grid feeding with the CM-UFD range


ABB's grid feeding monitoring relays detect unusual events in the public power grid and automatically disconnect and reconnect the renewable power plant.


ABB’s CM-UFD range are multi-functional grid feeding monitoring relays, installed between the renewable energy system and the public grid. The innovative relays guarantee grid stability and prevent blackouts. If the public grid’s voltage or frequency moves out of the permitted ranges, the device uses a decoupling unit (e.g. contactor or breaker Tmax XT) to separate the renewable energy system from the public grid. As soon as the grid is stable again, the system is automat- ically reconnected.

The CM-UFD range provides different monitoring functions in accordance with several local grid feeding standards to detect over-/undervoltage and over-/underfrequency.


The device measures the ten-minute average value, voltage increases and decreases as well as any changes in grid frequency. The rate of change of frequency (ROCOF) and vector shift monitoring to detect a loss of mains event can be easily configured.


  • Highly accurate measurement and setting
  • Modbus RTU communication interface and ABB ABilityTM EDCS connectivity
  • Functional safety - single fault tolerances
  • Clear multiline, backlit LCD display
  • Intuitive and user-friendly menu
  • Event storage built-in
  • Pre-settings meet several local standards
  • Type-tested to a number of local grid feeding standards by TÜV Süd
CM-UFD.M G99 relay
Modbus RTU communication

The CM-UFD.M*M range is equipped with an RS485 interface based on the Modbus RTU communication protocol. This communication interface makes it possible to:

  • Visualize the process data
  • Store process data
  • Remotely trip the device

This enables owners of renewable energy resources to:

  • Integrate the CM.UFD.M*M range into ABB AbilityTM EDCS
  • Perform remote monitoring via SCADA system
  • Use the measured value from the grid for active power control and power factor correction
  • Conduct remote maintenance and failure analysis
Modmus RTU Communication

Connectivity to ABB AbilityTM EDCS

Parametrize with Ekip Connect and access data no matter where you are

The cloud-based service AbilityTM EDCS enables customers to monitor the condition of CM-UFD.M*M in real-time and access the diagnostics remotely. This functionality is very important when operating in the field fo critical power.

The grid feeding monitoring relays can be connected to the cloud directly by using Ekip Com Hub module. Another option is to connect via Modbus RTU when there is some other device equipped with the Ekip Com Hub

like the Emax 2 air-circuit breaker.

The grid feeding monitoring relays can be connected to the cloud directly by using Ekip Com Hub module. Another option is to connect via Modbus RTU when there is some other device equipped with the Ekip Com Hub

like the Emax 2 air-circuit breaker.

In addition to the Ekip Connect 3 software, the following hardware is required:

  • Ekip UP (min. firmware 2.23)
  • Ekip Com Hub (min. firmware 1.18)
  • Ekip Com Modbus RTU (min. firmware 2.28)
  • Ekip Supply
  • Ekip T&P cable
  • CM-UFD.M*M (min. firmware 1.0.1)

Power islanding detection

Protect your workers with loss of mains detection

An additional phenomenon that can be detected by the CM-UFD range is Islanding, or loss of mains power.

 If a section of the network is separated by energy utilities (e.g. for maintenance) it may be uninten- tionally supplied with power by the generating plant contained therein. Within this power island there is no possibility to control consumed and generated power, thus frequency and voltage might vary significantly.

Under- and over frequency monitoring might not be sufficient to detect this inconsistency of voltage and frequency which can damage electrical devices. Islanding can also be dangerous to utility workers who may not realize that a circuit is still powered. It may also prevent automatic reconnection of devices.

 ABB’s grid feeding monitoring relay prevents this by shutting down the generator when it is decoupled from the public grid.

Easy installation and maintenance

Operate the device remotely and monitor your renewable energy plant

 CM-UFD Benefits

Global availability and pre-set standards

Easy installation and handling - wherever you are in the world

 A reliable solution that takes country-specific requirements into account: the CM-UFD range is already pre-set to local requirements, making installation quick and simple. Additionally, the devices can also be set manually with the display and used all over the world. 

Countries with a dedicated local standard (in red)

Countries referring to an existing local standard or using a product with reference to another dedicated standard (in grey)

CM-UFD.M*M range

Ordering information

The CM-UFD.M*M monitoring relays monitors voltage and frequency in single- and three-phase networks. In conjunction with inverters with integrated island network detection, this corresponds to the conditions for grid and system protection according to several local standards


Rated control supply voltage

Measuring range

Order code


24-240 V AC/DC

L-L: 0-540 V AC / L-N: 0-312 V AC



24-240 V AC/DC

L-L: 0-540 V AC / L-N: 0-312 V AC



24-240 V AC/DC

L-L: 0-540 V AC / L-N: 0-312 V AC



24-240 V AC/DC

L-L: 0-540 V AC / L-N: 0-312 V AC


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