The economical alternative

The economical alternative to grid expansion – optimal grid capacity utilisation: the integration of increasingly decentralised energy sources feeding renewable energy into low-voltage systems presents energy providers with increasingly greater challenges.

The specified nominal voltage range of +/- 10% according to DIN 50160 only allows a maximum voltage rise of 3% for decentralised energy sources. The remaining bandwidth must be available for medium voltage, voltage drops, and setting accuracy. In this context, more and more network operators are being forced to undertake expensive expansion activities in their grids, even though the available power capacity in the affected low-voltage distribution network is still far from being reached.

This is precisely where the core problem of adherence to the voltage range becomes the focus of a variable local network transformer, which adjusts the voltage dynamically. By decoupling the voltages in the medium and low-voltage networks, 11 percent, rather than 3 percent, are now available for voltage spikes that occur while feeding into the low-voltage network. In many cases, use of this type of controllable local network transformer enables network expansion to be omitted completely or at least significantly reduced in the few remaining cases.

In each case, the already available operating equipment can be utilised to a high degree by the network operator resulting in more economical operation.

The ideal solution for power distribution network operators

Maintenance-free, long-lasting     
  • no lifetime-limited electronics in the circuit breaker
  • maintenance-free for its entire lifespan thanks to vacuum technology
  • lifetime analogy to conventional local network transformers
Maximum operating reliability
  • critical operating conditions are excluded by the reactor principle
  • a communication interface enables integration with the control room as required
  • the SmartActiveTransformer features the entire know-how of more than 35,000 vacuum switches and over 10,000 reactor switches develeped by Maschinenfabrik Reinhausen, which are used around the world
Low lifecycle costs
  • 700,000 reliable circuits make maintenance ennecessary
  • the on-load tap changer operates reliably throughout the entire lifetime of the transformer
  • motor and controller may be easily replaced as required
Fit for the future

  • a maximum of 9 operating positions and step spacing of up to 3% enable a control range up to 24%
  • the on-load tap changer is also configurable asymmetrically for situations primarily featuring loads or primarily featuring feeds
  • The voltage range of  +/- 10 % as per DIN 50160 can be fully utilised


Control algorithm

The integrated voltage regulator enables completely autonomous operation, whereby the SmartActiveTransformer independently adapts to the current network conditions. For this purpose, the voltage carried by the low-voltage bus bar includes all 3 phases, and the control parameters react accordingly. Threshold hunting also prevents build up in the switch due to phase asymmetry.

The definable parameters for the control algorithm include the target voltage (Usoll), the step voltage (Ustep), the dead time (t1), and the threshold for the high-speed transfer switch (So). In addition to parameterisable standard algorithm, individual alternative algorithms may also be implemented as required. Standard protocols also make communicative connection with cross-systems possible.