As one of the largest utilities in the Netherlands, Stedin bears a lot of responsibility. Over 2 million customers depend on it for electricity, including government offices, major financial and industrial customers, and the Port of Rotterdam, Europe’s largest port.
Driven by the desire to better serve its customers, Stedin looked for a solution that would significantly reduce the duration of potential power outages. The challenge was to come up with a high-quality, cost-effective means of quickly re-energizing the MV network in case of a fault.
“We needed more monitoring in our system and to combine that with the reduction of customer minutes lost, we came up with an idea to install a self-healing grid,” said Edward Coster, an expert in Stedin’s SM Management Department.
Overcoming the challenge
After considering its options, Stedin turned to Schneider Electric™. The two companies already had a relationship, having worked together on various projects, and the Schneider Electric team was able to foresee and avoid a number of technical problems. What resulted from this partnership was a decentralized, underground self-healing network, the first of its kind in Europe.
The self-healing solution is based on an existing product — the Easergy T200 Remote Terminal Unit — which could be deployed with only minor reconfiguration, significantly simplifying the project and speeding up the return on the investment. In addition, thanks to the flexibility of the Easergy T200, the solution is scalable and replicable in other locations.
How does it work?
Once installed at the main MV substations in an open-loop network, Easergy T200 units establish peer-to-peer communication using a virtual private network. If a fault occurs within the network the control center is notified, but there’s no need to wait for an operator response. Instead, the Easergy T200 units communicate with one another automatically to determine where the fault has occurred, isolate it, and re-energize the unaffected areas of the grid.
“The self-healing solution allows Stedin to locate and insulate the MV fault as quickly as possible while disturbing the minimum of customers,” commented Lucas Pellegrin, Feeder Automation VP at Schneider Electric.
“When I say as quick or as fast as possible, it is less than 1 minute to reconfigure the global network,” he added.
Adding intelligence to the grid
Stedin’s underground self-healing solution, comprising an open-loop network of around 33 MV substations in downtown Rotterdam, was inaugurated in June 2012. The whole project took around a year to complete, from design to energization.
“I believe that we have to serve our customers better and better, so we put the self-healing network — and also more intelligence — in our grid,” said Marko Kruithof, Grid Coordination Manager at Stedin.
Now, in case of an outage that might otherwise last 2 hours, the system cuts the time to re-energize the unaffected parts of the grid to under 30 seconds. That translates to greater power availability for important commercial customers, as well as vital government offices. Also, by automatically isolating the affected area, it takes less time to find, diagnose, and fix the problem.
“Electricity is very important nowadays. It’s like water and air. It’s everywhere”, Kruithof stated. “An outage must be as short as possible, because when there is an outage life stands still.”