Eaton Grid and System Protection to VDE-AR-N 4105 – in the 14 kVA to 866 kVA Rating Range (20 A to 1250 A)

Eatons Electrical Sector is offering individual components for network and system protection to VDE-AR-N 4105, as well as ready to install and connect complete solutions. These individual components include contactors with a low sealing power and motor-operated circuit-breakers with low power undervoltage releases.

The VDE-AR-N 4105 application rule has been in force since August 1, 2011. Transition periods are intended to simplify its introduction and implementation: The application rule has been binding for photovoltaic installations on low voltage networks since January 1, 2012; for other decentralized generation plants such as CHP power stations, biogas and wind turbine generators, the date is July 1, 2012. It is intended that VDE-AR-N 4105 becomes a fixed element of the technical connection requirements (TAB) of a grid operator. This changes the design of the protective measures, settings for protection and monitoring devices as well as general connection requirements accordingly.

Additional measures have to be implemented in order to further ensure the grid stability of the rapidly growing number of decentralized power generation plants in Germany. These measures are specified in the application rule: This includes, for example, the compulsory disconnection of generator plants when the low-voltage grid is subject to impermissible voltage or frequency deviations. The VDE-AR-N 4105 recommends for this the use of a coupling switch implemented in the form of two electrical switching devices connected in series that are controlled by a relay that monitors grid frequency and grid voltage. If the values permitted by the regulations are exceeded, the generation plant is automatically disconnected from the grid. If the grid voltage or frequency returns to the permissible range, the installation is automatically reconnected. Application rule VDE-AR-N 4105 also stipulates that: The disconnection must be failsafe. With installations >30 kVA a central grid and system protection is required. This is implemented at the location of the meter. With installations <30 kVA, the grid and system protection implemented in the power inverter is sufficient.

As well as ready to install and connect complete solutions for network and system protection to VDE-AR-N 4105, Eaton is also offering individual components such as contactors with a low sealing power and motor-operated circuit-breakers with low power undervoltage releases. The contactors are permitted for use as coupling switches in systems up to 100 kVA. Motor-operated circuit-breakers or switch-disconnectors, for example, can be used for larger installations. Eaton has the right 3 or 4-pole solution in its portfolio for any application. This enables a rating range from 14 kVA to 866 kVA (20 A to 1 250 A) to be covered.

Ready to connect grid and system protection up to 100 kVA: For installation sizes between 30 and 100 kVA, Eaton has developed a compact and ready to connect combination in an insulated enclosure with IP65 protection that meets the requirements of VDE-AR-N 4105. It consists of two contactors connected in series that are actuated by a grid and system protective relay and are supplied pre-assembled inside an enclosure. The newly developed grid and system protection is installed between the power inverter and grid connection. Users install the combination in a wall mounting. The DILMP contactors used are particularly efficient with a sealing power of 2.1 W, thanks to their electronic solenoid drive.

The Eaton grid and system protection comes in four rating classes and two frame sizes: Size 1 to 43 kVA and 55 kVA and size 2 to 86 kVA and 100 kVA.

NA grid and system protective switch from 14 kVA to 866 kVA: VDE-AR-N 4105 excludes the use of contactors as coupling switches for generation plants >100 kVA; motor-protective circuit-breakers and mechanical circuit-breakers are expressly approved. However, switch-disconnectors also meet the requirements of the application rule. Eaton offers a complete range for this.

The coupling switches are assembled by the user with two remotely operated circuit-breakers or switch-disconnectors connected in series. Other necessary components are undervoltage releases and the grid and system protective relay. This combination, with a short-circuit breaking capacity of 50 kA, is suitable for grid supplies of up to 2 × 1000 kVA/ 400 V transformer output. Alternatively, Eaton is offering switch-disconnector combinations with an upstream fuse for short-circuit protection. The two breaker types, with remote operators with a low heat dissipation and undervoltage releases with <3.6 VA sealing power, are both ideal components for high efficiency systems. Thanks to their space saving and compact design they can be fitted side by side or on top of each other, depending on the application. An extensive range of accessories with box and control cable terminals ensures simple connection.

A circuit-breaker can also be combined with a switch-disconnector for the basic disconnection of an installation. The use of a circuit-breaker or switch-disconnector with one contactor or two contactors would technically also be a solution. However, this is not defined in the application rule. The responsible grid operator should therefore be consulted in this regard.

Eaton is present at the Intersolar Europe, Munich, in Hall C3 Stand 143.

More Info: www.eaton.de/electrical Quicklink ID: ES2501
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Caption: Eaton grid and system protection to VDE-AR-N 4105 – in the 14 kVA to 866 kVA rating range
Keyword: Grid and system protection, renewable energy, photovoltaics, wind energy plants

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