Ensto's automated load break switch disconnectors protect customers from power outages even in harsh arctic weather conditions

Finnish Lapland inside Arctic Circle has several major ski resorts as well as remote residents right next to eastern border. Auguste load-break switches (LBS) are not afraid of responsibility or challenging weather conditions, instead they do their job securing electricity distribution despite storms, snow, or ice.

"The length of the ending branch in our distribution network can easily be more than a hundred kilometers," says Mika Ulkuniemi, design engineer and network operations manager in Koillis-Lapin Sähkö, the distribution system operator in the region.

The company has only 12,550 customer connection points, but the distribution network is as long as 3,400 kilometers. Its overhead lines run through endless forests and cross wide swamp areas. Underground cabling covers only four municipal centers and three major ski resorts like Pyhätunturi.

Protection for long branches

The length of 20 kV distribution network of the operator is 1,880 km and has 1,220 distribution transformers. Significant part of it consists of overhead line branches. In those were also the first three of company’s Ensto Auguste load break switches installed.

One of them ensures supply to those customers of the Pyhätunturi substation, who are located along the ending 32 kilometers long overhead line. It guards the last 11 kilometers of the branch, including six distribution transformers.
If a fault situation occurs in that part of the branch, Auguste instantly disconnects it from the network. Then electricity is restored to customers in the preceding part of that branch, which has a total of 24 distribution transformers.

'Auguste significantly speeds up
the recovery of electricity distribution
in the event of a fault'

The speed of recovery is of huge importance to an area with a lot of people and activities, especially in winter. Then the tourist season is high and it is cold and dark. Auguste also speeds up finding the location of the fault, because the search can be limited immediately to the last part of the branch, which was isolated from the network.

The other two Augustes has been installed in sparsely populated, remote area close to eastern border. Both are in the same place where a long network branch splits in two 40-kilometer lines to control.

Recovery in two minutes

“Auguste significantly speeds up the recovery of electricity distribution in the event of a fault. It disconnects the faulty branch in less than two minutes, even before on-call supervisor in charge gets an alert about the situation. At the same time, the distribution of electricity to other customers of the branch has already been recovered,” says Ulkuniemi.

He describes a situation where Ensto Auguste is not installed in a branch. In that case, finding a fault, repairing it, and reconnecting can take a long time, especially in winter. A typical cause of a power outage is a storm or condensed heavy snow that fall trees over the line. Outside working hours, on-call supervisor receives an alarm and notifies installers.

“For example, if the fault site is 200 kilometers away, a pair of installers will be there in 3-4 hours. Once the equipment is finally caught near the line by the roadside, the search for a fault location in the terrain on snowmobiles in deep snow can begin, often for many kilometers. Repair in challenging conditions is a demanding task and an extreme test of tools and equipment. I remember one time when the temperature was -48 C, which is -54 F, and there was no choice but go on.”

With traditional remote controlled break switch, it can take a long time to find the fault section and recover the electricity to the rest of the branch. The speed of Ensto Auguste shortens the duration of a power outage and speeds up access to repair work. This is of great importance financially and in terms of customer service.



'I think Auguste is the best choice,
especially for the ending branches
of overhead lines'


Works as promised even in harsh conditions

Auguste minimizes the time of outage of the terminating overhead line branch by separating the rest of the faulty branch during the automatic reconnection period. In this way, electricity is returned to the customers at the beginning of the branch immediately without hours of waiting.

“This is such a significant advantage that we ended up choosing Auguste instead of traditional remote-controlled disconnectors. Our experiences prove that they work as promised even in very demanding conditions,” says Ulkuniemi.

“We add a few new remote disconnectors every year and replace the old ones with new ones. I think Auguste is the best choice, especially for the ending branches of overhead lines.”

In addition to speed, he appreciates reliability. It is based on, among other things, a closed structure. The device has heating and batteries, and there are no moving parts outside but only simple connections to the overhead line. It withstands the extremely severe frost of the Arctic Circle as well as strong storms with water, snow or ice. The reliable design also includes that the device is completely maintenance-free.


Activity and competence created trust

Mika Ulkuniemi thanks the people of Ensto and especially Antti Leinonen, who is responsible for sales in the northern region, for the active role that led to installing Augustes.

“They are competent and know both the technology and the needs of distribution network operators. Contacting and presentation of new products is regular, even though we are quite small operator and far to the north.”

“I am interested in the new technology, and they have offered me opportunities to get acquainted with it, for example, by visiting Ensto's product development. You can get the best idea of the new solutions by using them yourself. Augustes have functioned in our harsh conditions as promised and we are very pleased with them.”


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