When it was time to upgrade four of its substations built in the 1980s, Swedish distribution system operator Sala-Heby Energi Elnät (SHEAB) chose to upgrade their installed medium-voltage switchgear with new smart protection relays and refurbish existing circuit breakers.
Reliability and availability of power supply are crucial for distribution system operators (DSOs). Having previously refurbished around 50 circuit breakers for SHEAB with great results, ABB now also had the privilege of upgrading SHEAB’s protection and control to modern technology.
"We are very pleased that SHEAB is entrusting us with upgrading protection relays in four of their substations. With the new smart protection relays, they gain access to a wide range of technical innovations that bring both increased reliability and easier maintenance," said Per Winther, product specialist at ABB.
Sala-Heby Energi Elnät, part of Sala-Heby Energi, operates predominantly in the municipalities of Sala and Heby, north of Västerås in central Sweden. Around 14,000 customers are dependent on SHEAB delivering reliable electricity 24/7 and ensuring the grid and its associated equipment is in top condition.
"We were very pleased with the circuit breaker refurbishment that ABB did for us. With the new, more advanced protection relays that are now being installed, we are securing the power supply’s reliability for many years to come and can better meet new challenges in the networks," said Andreas Ringvall, Grid Operations Manager at SHEAB.
Reduce downtime and improve reliability with upgrades
The circuit breakers and protection relays in question are installed in Safesix medium-voltage switchgear. This type of switchgear is amongst ABB's most tried and tested products. Up until 2002, when Safesix was taken out of production, ABB had delivered around 35,000 such switchgear, half of which to customers in Sweden. And they are still an important part of Swedish substations today.
"We estimate that about half of those switchgear are still in active operation. This means there is a need for maintenance and upgrades of both the switchgear panels and all the devices included in them to secure operation in the future as well," said Per Winther.
ABB offers a wide range of services to upgrade and maintain switchgear. “When you continuously perform maintenance, you can ensure both continued high availability and safety for personnel. And not least, you extend the life of your investment," says Per Winther.
Andreas Olsson, Operations Manager at SHEAB 
Andreas Ringvall, Grid Operations Manager at SHEAB 
Per Winther, Medium Voltage Product Specialist at ABB
The right time for upgrading the protection relays
“The existing protection devices are from the 1980s, and it's becoming difficult to get hold of spare parts. We wanted to make sure we have good protection that can also give us more information, also remotely," said Andreas Ringvall.
The new protection relays being installed are REF615 from ABB’s Relion® product family. This family of smart protection relays offers protection, control, measurement and monitoring of power systems for utilities and industry. The large graphic display makes it easy for technicians on-site to get detailed information and the customer can also add their own functions.
"These new advanced protection relay systems offer a completely different level of control and reliability. Now the customer knows the status of the equipment continuously and can conduct more efficient event-based maintenance," said Per Winther.
Another advantage is that the compact and pre-configured protection relays in the Relion® family are faster to install at the customer sites.
"The time savings are probably 30 percent compared to older protection relays. The plug-and-play design makes assembly and disassembly easy, and the customer can have a pre-configured spare protection relay on the shelf in case of problems, just as many today also have spare circuit breakers.”
“ABB will replace a total of 46 relays with a new generation of smart protection relays at four of SHEAB’s substations. About 75 percent of the replacement activities have now been completed,” said Andreas Olsson, Operations Manager at SHEAB. “We started in the fall of 2023 with the two largest substations, in Heby and Morgongåva, and we will now continue with two smaller stations in Sala municipality.”
