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Mains protections

A family of mains protection modules that provide the necessary protection functions to meet the requirements of all applications where generators operate in parallel with the mains.




Utility Protection Relay

InteliPro is a highly flexible interconnection/mains decoupling protective relay and with extensive protective functions it meets the strictest utility interconnection requirements and can be used in wide range of distributed generation applications.

  • Dynamic grid support
  • QU protection (directional reactive power undervoltage protection)
  • Certified according to IEC 60255, VDE 0126-1-1 and BDEW
  • Applicable for requirements of G59/3, G10, G83 and IEEE1547 and VDE-AR-N 4105 
  • Possibility to enable the appropriate functions required by your utility
  • Detailed history log fully records the nature of mains disturbances including brown-outs
  • Watchdog reporting provides increased reliability of the installation
  • Advanced on-line communication notifies immediately of changes in the mains-connection
  • Door-mount possibility
  • For more technical details, kindly see the datasheet
  • InteliPro features a new Pole Slip protection. Click to find out more about Pole Slip 

InteliPro is 100% replacement of the successful product InteliProtec.

MainsPro Lite
MainsPro LITE
Mains Decoupling Relay
MainsPro LITE combines simple installation and usability with valuable mains protection.

This product offers essential protection for preventing the supplying of power into an islanded grid and is an attractive choice when vector shift and frequency rate change of frequency protections are not required. It represents a cost-effective solution for mains connected applications including gen-sets and renewable energy sources. It brings to the customers smart solution to installations where preferably voltage and frequency protections are requested.
MainsPro LITE offers:

  • True RMS measurement for increased accuracy and reliable evaluation of failures
  • Compact design for installation in restricted spaces
  • Suitable for low voltage installations
  • Simple wiring with detachable connectors
  • Two-stage over/under voltage protection
  • Two-stage over/under frequency protection
  • Floating average overvoltage protection
  • Phase supervision
  • Freely assignable variety of binary inputs and outputs
  • Event history log
  • Auto fault reset
  • CB Failure protection
  • Increased resolution of frequency setting
  • ANSI 27,59, 81H, 81L, 47 Certifications


20121102 MainsPro_900

Mains Decoupling Relay

MainsPro is a protection relay for mains-to-parallel applications, including generator sets, cogeneration, micro turbines or renewable energy sources such as photovoltaic plants or wind turbines. It provides adjustable voltage, frequency and loss of mains protections to safeguard both the distribution network and the generators.

  • MainsPro complies with IEC 60255, G83, G59/3, UL508, CEI 0-21, IEn NR 005/2012, VDE V 0126-1-1 and VDE-AR-N 4105
  • Flexible supply voltage and measurement range
  • Suitable for standard DIN rail installation or door-mount (optional)
  • Friendly interface with easy setting (no SW tools needed)
  • Simple wiring with detachable connectors
  • Remote binary communication
  • Compact design allows intallation into restricted spaces
  • Lost of Mains function, History track function (Last 5 events history log)
  • Integrated mechanical lock to secure your setting
  • Breaker failure protection
  • Watchdog relay output
  • Increased resolution of frequency protection setting
  • Resistance to frequency jumps
  • For more technical details, kindly see the datasheet

MainsPro is a 100% replacement for the successful productNPU-FUV

Maintaining power supply stability

As the installed capacity in decentralized sources of energy continues to increase, the distribution system can become less stable resulting in a fluctuation of grid parameters such as voltage and frequency. To keep the equilibrium and ensure safe operation of the grid, mains protection is essential for every power source operating in parallel to grid.

As a result, Utilities and Distribution Network Operators (DNOs) issue regulations, which every site generating power must comply with. These regulations highlight the need for protection relays in order to protect the distribution network from dangerous effect of asynchronous generation and minimises the likelihood of equipment damage caused by disturbances coming directly from the mains network.

The importance of mains protection to Utility Companies

  • Ensures safe balanced operation of the distribution system
  • Guarantees reliable delivery of high quality electricity
  • Allows smooth involvement of the distributed generation
  • Enables remote control of power supply sources

The importance of mains protection to Plant Operators

With the responsibility for reliable protection of plant, operators must install and maintain adequate protection equipment. Protection settings at the interfaces between the network operator and the plant operator/connection owner is governed using country specific guidelines, whilst the network operator determines whether and which protection devices are to be sealed or otherwise protected against alterations*.

The plant operator then must ensure

  • Compliance with locally applicable standards and rules
  • Compliance with technical conditions on connection to the distribution network
  • Prevention of generator damage caused by grid parameters out of limits
  • Reduction of down time after generation disconnection / interruption

* extract from German standard BDEW

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