91052 Erlangen


Seit 2013


FW-5, FW-50, Compass B, Janitza UMG103, UMG 505, UMG 605


IEC 60870-5-104, IEC 62056-21, Modbus TCP, Modbus RTU

The Anger is a residential area of Erlangen with a large number of local energy resources, especially PV roof systems producing up to 30 kWp. Because of the previous lack of metering points in the low voltage grid, there was no transparency regarding the potential change in load flows and the remaining grid capacities in the area.


So the decision was taken to use the Anger as a pilot project for comprehensive grid monitoring and control. The new requirements specifi ed by the Bundesnetzagentur (German Federal Network Agency) also played a role as they now allow output control of PV systems to take place at the low voltage level. A substantial reduction in the administration and maintenance times and longer update intervals are the benefi ts hoped for.

Technical implementation

The aim was measurement of current, voltage, power and quality data on the busbar and also at each low voltage outfeed. The information is recorded with the aid of various grid analysis systems made by Janitza (UMG 605, UMG 505 and UMG 103) and Horstmann (ComPass B) which are linked via Modbus RTU or Modbus TCP.
For registering the actual feed-in of the PV systems, 30 intelligent meters have also been linked up using the IEC 62056-21 protocol – a practical solution particularly in
the case of limitation by the tone frequency ripple control systems fi tted, which cannot provide feedback themselves.

It has been possible to make use of the Erlangen public utilities’ own high-capacity fibre-optic cable network to transmit those large volumes of data. The data from grid analysis systems and meters is transmitted in duplicate and both copies not only stored in their entirety in separate databases but also managed by the SAE telecontrol technology, which selects the data and passes it on to the control system. The selected data is visually displayed at the central control station and used for calculating the load fl ows. A simulation for assessing the further expansion possibilities regarding PV concluded that with the maximum possible development of PV systems in the Anger area, a voltage spread of 5% would result – the local grid capacities are already fully utilised.

“Of the diffi culties that we encountered with the initial link-up of our Horstmann or Janitza equipment in this area, we will remember one thing: the speedy, uncomplicated and profi cient assistance from the SAE hotline. The enjoyable co-operation with Mr Ohlendorf during the commissioning of the meter connections also contributed substantially to the speedy link-up of the meters via the FW-5 gateway. We were able to clear up minor misunderstandings straightaway over the phone.”

Christian Bühl, Erlanger Stadtwerke