26725 Emden




SG-50, FW-5-GATE


IEC 60870-5-104, IEC 60870-5-103

Stadtwerke Emden GmbH has been supplying the town of Emden and its people with gas for 150 years now – and for 115 years with water and 88 years with electricity. 51,362 inhabitants need these supplies.


Stadtwerke Emden operates extensive infrastructures to guarantee this – the gas network is just under 500 km in length, the majority in the high pressure range. With almost 600 km of distribution network, the water supply is guaranteed and power is distributed by means of about 240 medium voltage stations, almost 200 km of medium voltage network and a good 650 km of low voltage network.

This project is also to include a wind farm with twelve wind turbine generators of different power ratings and a total connection power rating of 31 MW with QU protection. All of this retrofi tting stemmed from the fact that existing Siemens 7SJ protective equipment lacked a communication interface. Whilst a conversion would generally have been possible, it would have resulted in the fi eld in longer stoppage of operations with removal, sending in, actioning time and subsequent re-installation.

The decision was made to go with the guard-line SG-50 from SAE – for two reasons:

  1. The modular design of the protection modules enables the protection functions (even QU protection) to be “adjusted” by specifying a few parameters, and do not need, as with many other manufacturers, complex programming from different fragments
  2. The protective functions of the SG-50 can be aligned to changed requirements by loading separate software modules (even retrospectively)

Three SG-50s each with four current and four voltage inputs as QU protection, with fault locator, system automation and user interface, were fi tted. A dual busbar system was implemented with a busbar isolator, circuit breaker, cable outlet isolator and earth switch. Switch error protection was realised in full by the system automation in the SG-50. Communication to the NLR is over an optical interface to a net-line FW-5-GATE, and from there over Ethernet to the control centre in accordance with IEC 60870-5-104.

Stadtwerke Emden GmbH was extremely happy with the conversion and is already looking forward to new projects with the guard-line products from SAE IT-systems.