ESBJERG, WE HAVE A PROBLEM

There may be very few similarities between the Apollo 13 moon flight and Vattenfall’s Surveillance Centre in Esbjerg, bar one: The relaying of information due to technical malfunction. Offshore WIND speaks to Jan Jørgensen on the complex and challenging job of monitoring Vattenfall’s wind turbines.

Jan Jorgensen from Vattenfall is manager of Vattenfall’s Surveillance Centre where he is in charge of a team of eight surveillance technicians . The centre is manned 24/7, during regular working hours two surveillance technicians are present, with one during nights and at the weekends. Jorgensen: “The surveillance technicians have a technical background as e.g. auto mechanic, electricians etc. It is not necessary to have a background as wind turbine technician, but off course not a disadvantage. Vattenfall is very open to job-rotation and actually the wind turbine technicians who worked here previously in the surveillance centre now have other positions within Vattenfall. When a new surveillance technician is employed he/ she always starts with three to four-month job training period together the experienced technicians before having own shifts.”

Manning the surveillance centre puts the technicians in charge of approximately 1,000 turbines divided over five different countries: Sweden, Denmark, the Netherlands, Germany and the United Kingdom.

Jorgensen: “We monitor each and every turbine from out office in Esbjerg. We co-own some wind farm, DanTysk for example, but these are also monitored from here. The links to monitoring the wind farms differ from site to site, for instance we monitor a few via satellite connection for other more modern wind farms we use fibre-optics. On some of the major wind farms, such as Horns Rev 1 we have a video camera mounted on the substation so we can see all the turbines there, it also means we can keep in touch with boats and the helicopters. All in all, we require a very stable internet connection to the site.”

SCADA

“We have connected 38 different turbine types from different manufacturers. Whenever you buy a wind farm it comes with a surveillance tool. Our team collects all the data and we put it into our own system. We want to be able to control all the turbines and do it in a similar manner. We monitor the same data for each turbine, though the parameters are different depending on each wind farm and if it is onshore or offshore. For us main facts are: is the turbine running or has it stopped and why?” comments Jorgensen.

A SCADA system (Supervisory Control and Data Acquisition) is used in the Surveillance Centre, which was developed from scratch at Vattenfall’s office in Kolding in Denmark. Jorgensen explains: “At any given times we receive over 1,000 different kinds of data. From the turbine, but also from sensors in the blades. If a turbine has stopped, we see it directly in our system. All stops are uniformly categorised and in 2016 from January to July we have had a reaction time of 99.6 per cent within five minutes to start investigating the possible problem. Some turbines can be restarted remotely; others require the assistance of a local technician.” In 2015 more than 2,500 turbines were restarted, meaning more than 17 million kWh could still be produced, just one example of the importance of the surveillance technicians’ work.

Remote restart

When a turbine cannot be restarted remotely, a local technician is alerted. Vattenfall also monitors how the technician is doing and where he is: people-tracking. Jorgensen: “The service technicians call us when they enter the turbine, tell us what they are going to do and then call again when they leave the turbine. This is an important safety improvement that was first introduced in onshore turbines in Denmark and Sweden, but now sites in the Netherlands and the UK are contemplating to join the system.” For the offshore turbines this monitoring is critical, even if it is only to avoid leaving someone behind when the crew transfer vessel returns to port.

Faults causing downtime

Downtime is caused by various types of faults. “For instance”, says Jorgensen: “We can encounter temperature errors where turbines need to cool down, this is could be down to electrical faults or vibration. Once a turbine has cooled sufficiently we restart it remotely. Vibration is often due to the effect of the wake when the wind is from a specific direction or high winds and sudden changes in wind direction. We don’t shut down wind farms due to wind speed, each individual turbine will shut down itself during wind peaks. This also differs per turbine type or manufacture; some can handle wind speeds up to 25 metres per second others 30 metres per second.”

From quiet to alarm

When asked if J0rgensen has ever experienced a very, very busy day, he comments: “It no secret we have had two fires on Horns Rev 1 and in these cases we are also in charge of the emergency response. Sometimes you can go from a very quiet day to an alarm. A fire in a turbine makes for a very, very busy day. You immediately start contacting the necessary people and shut down what is required and continue monitoring the situation until it has been stabilised”

“In the future I think we will become more active in monitoring substations. A new semi-automatic people tracking system is something we are also looking into. To be able to atomise the communications link though a swipe card or perhaps an app for the phone – to help tracking the technicians more efficiently. Currently technicians call us and let us know what and how they are doing and on some days we have more than a 100 or 130 phone calls. I believe it is important to streamline this information and system.”