By Kari Williamson

On the Swedish island of Gotland, where a large part of the electricity comes from wind power, the grid will be upgraded and a so called 'self-healing grid' will be introduced.

Ulf Ysberg, who leads the Rural Grid Development sub-project within Smart Grid Gotland, says: “We will introduce sensors, disconnectors, reclosers and communication devices in all parts of the grid, all controlled from the operations centre. This will enable us to manage the power-flow direction, increase quality and reduce cost.”

Sensors help the system to quickly locate and disconnect failing parts of the grid and at the same time restore power to as many other customers as possible.

“We believe that this will enable us to reduce the average outage time by up to 20-30% for our customers,” Ysberg says.

Measuring the load and the power flow will also make it possible to use the grid better. Today, grid owners typically suffer a 6% energy loss in the grid. If the current loads are known, alternative feeder routes can be chosen to decrease that figure. The low-voltage grid will also be monitored to detect failures automatically and to address them quickly.

“The big challenge in this project is to develop a sophisticated support system that can collect and handle all data from the substations and measuring points,” Ysberg adds.