More transparency in the medium voltage grid

Description

A wholly-owned subsidiary of Stadtwerke Duisburg AG, it has been trading as Netze Duisburg GmbH since 14 October 2014. Among the core tasks of the distribution grid operator are the planning, operation, expansion and maintenance of the supply grids for electricity, gas, water and district heating. The length of the regional grid is around 9,100 kilometres.

The Duisburg grid operator has been using SAE components in various areas for a
good five years. The decision to use the net-line FW-5 was taken partly because of its
integrated Modbus interface for connecting smart grid applications. Other reasons for using the net-line FW-5 included its compact design, its simple, safe and wireless programming on site via the Bluetooth® interface, and its support of all commonly used communication protocols. Now, all new projects are implemented with the FW-5.

In the electricity sector, the units are used for feed-in management in renewable energy plants and for equipping new grid substations and converting existing ones for local grid automation.

There are over 1,000 localised electricity generation plants in the Duisburg distribution grid. Photo-voltaic arrays make up the majority of them and, together with a good 20 modular CHP plants and 3 mine gas plants, have an installed generation capacity of roughly 27 megawatts. Of the photo-voltaic farms, 26 have switchgear cabinets with FW-5 telecontrol units installed, while there are a further 13 wall cabinets with FW-5 units in the modular CHP plants. As well as for output control of the generating plants according to EEG §9 Paras 1 and 2 (German Renewable Energy Act), the compact telecontrol units are also used in the latter case for remote switching of the grid coupler switch.

When fitting out grid substations for local grid automation, Netze Duisburg GmbH relies on a combination of the FW-5 and the Horstmann ComPass B short-circuit and earth fault indicator. That combination enables greater transparency in the medium voltage grid and allows fast fault isolation in the event of a failure. The combination has also proved itself in practice because of the ease of implementation of the Compass B quantity structure in the setIT configuration software.

In the area of gas pressure regulation stations, the Duisburg grid operator has install 39 FW-5 units. In this case, the measured data in the medium and high-pressure incoming lines and the medium-pressure outgoing line, and also the odorant concentration are monitored and communicated. Data transmission to the master telecontrol interface takes place via GPRS or a wired connection.

The company also uses SAE-IT components for magneto-inductive flow rate measurement in its water supply operations. Distribution stations have been fitted with FW-5 telecontrol units for 6 measurements. They analyse the water pressure measurement points and transmit the data established to the control centre.

All telecontrol components use the IEC 60870-5-104 protocol for communication between substation and telecontrol interface. If there is no facility for wired communication, data is transferred via radio signals using the GPRS network with VPN encryption implemented to protect the systems.

Smart Grid project team

The Smart Grid project team at Netze Duisburg GmbH was established in 2009 and is made up of young engineers from all sectors of the supply industry. The project team’s brief is to document the potential of smart grid applications in Duisburg and to initiate pilot projects for assessing the use of smart grid applications