About 10,000 end users in the center of the capital of Montenegro, Podgorica, are supplied from the substation called ‘Centar’. This includes many of the country’s health and state institutions, such as the Clinical Center of Montenegro and Children's Hospital, the Ministry of Defense of Montenegro, the National Security Agency, the Government of Montenegro building, and RTCG, the public service broadcaster of Montenegro, and a sports center.
One of the key priorities for CEDIS, the DSO that distributes electricity to up to 432,000 consumers in the country, is ensuring sufficient capacity and uninterrupted power supply to all the users, and to continuously develop its distribution network to ensure reliable electricity supply. In 2021, the company embarked on a demanding reconstruction project for the TS 35/10 kV Centar substation - an investment worth 1,3 million Euros.
For the substation, ABB delivered equipment that helps bring reliable and safe power throughout the entire power distribution network. This included 48 panels of air-insulated medium-voltage switchgear UniGear ZS1 equipped with Relion® protection relays and VD4 circuit breakers.
In the switchgear, ABB’s Relion protection relays play the important role of protection and control. The relays identify faults in the power system, and to re-establish power VD4 circuit breakers interrupt these fault currents. In this substation, CEDIS has both REF615, a dedicated feeder protection and control relay, as well as the RET620, a dedicated protection and control relay for transformer protection.
UniGear ZS1 medium-voltage air-insulated switchgear at the Centar substation. Photo courtesy of CEDIS. 
Relion RET620 is a dedicated transformer management relay for the protection, control, measurement and supervision of both power and step-up transformers, including power generator-transformer blocks, in utility and industrial power distribution systems. Photo courtesy of CEDIS. 
Relion REF615 is a dedicated feeder protection and control relay for protection, control, measurement and supervision of overhead lines and cable feeders in utility and industrial power distribution systems. Photo courtesy of CEDIS.
The upgrade project was carried out in the vicinity of a power station with 35 kV switchgear, which presented a range of challenges and specific demands. It was crucial that an uninterrupted and reliable power supply was ensured throughout the entire project. What’s more, rigid safety processes were in place to ensure a safe working environment for the personnel working in the energized area.
"We are grateful to have been a part of this important project that provides safe and uninterrupted power to the community”, said Dragutin Gorički, Senior Sales Specialist at ABB in Croatia. “The contract between CEDIS and ABB was signed during a very turbulent time - exactly at the time of one of the worst earthquakes in the city of Zagreb. However, thanks to excellent cooperation with CEDIS we were able to finish the project and make it a real success."
