An emergency power system with 5 units for a thermal power plant

Complex parallel operation with adjustable control devices

It was important to our customer to have a modern and redundant control system.

In the planning phase of complex power stations, we have to evaluate different aspects and select the optimal concept for our customer.

In our application example we compared the following aspects

  • Investment costs for the control devices
  • Cabling effort between the decentralized peripherals
  • Reliability (redundancy)

Due to the structural requirements, the emergency power systems including the associated control are located outside the building (container construction) and have to communicate with the master control (building construction), we decided in favor of the “Woodward concept”.

The “concept” essentially consists of the following components:



Central control:

The master control consists of:

  • a Woodward LS-6 control unit, for controlling and monitoring the generator coupling breaker
  • a redundant S7-1500, for communication with the control room, for controlling and monitoring the low-voltage breaker in the LVSG, the communication of protective devices in the LVSG, the communication to the Woodward system, and the communication to a workstation on which the entire system via WinCC Advanced is visualized.


Medium-voltage switchgear:

The customer was also supplied with two LS-6 control units for controlling and monitoring the mains incomer for installation in the medium-voltage switchgear.

Mode of operation:

  • The Woodward control units are connected together via a redundant Ethernet bus and exchange informations relevant to the function with each
  • The S7-1500 detects a busbar voltage failure and communicates this to the LS6 control unit. Important informations are transferred to the genset controls via the "LS6 flags" (without the need for cabling). With these “LS6 flags“, we can initiate emergency power operation or load test operation for the individual emergency power units.
  • The Woodward LS-6 control units for the generator coupling breaker / mains incomer recognize the status of the power station via the individual segments and adjust the frequency in the synchronization, and the active power of the emergency power units in the mains parallel operation.
  • Due to the division of the overall function into several control units, and the redundant networking, a device failure leads to a fault message but not to a failure of the overall function. Individual functions can continue to be operated.


If you have any questions regarding this application or other concepts, our technical sales team will be happy to assist you.

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