Serbia’s Elektrodistribucija (EDS) has launched a major project aimed at automating the medium-voltage electricity distribution network in collaboration with the French company Schneider Electric. The primary benefit of this project will be the restoration of power to end users within 30 seconds after a network outage or power failure.
Dušan Vukotić, the team leader and key expert for the technical aspects of the network automation project, explained that the medium-voltage network is the most important and dominant part of the electricity distribution system.
“In technical terms, it covers voltages of 35, 20, and 10 kilovolts. In terms of importance, it is the predominant network through which we supply our end customers, who are connected to the low voltage network. The structure of the network shows that the low-voltage network is much larger in size compared to the medium-voltage network. However, the main energy flows and the distribution network management mechanisms focus most on the medium-voltage network, which is why it is at the center of our current automation process,” Vukotić told Tanjug.
An intergovernmental agreement between Serbia and France enabled the realization of this project, which is based on a contract between EDS and Schneider Electric from 2023 worth €140 million. This amount will be used for the delivery of equipment, systems, and software for advanced management of the electricity distribution network.
“We started automating transformer stations in the 1980s. At the beginning of the 2000s, the intensive automation of the medium-voltage network began, with the introduction of relevant studies and adoption of network management concepts. For about 20 years, we have been developing automation solutions based on this concept, and we have been very successful so far,” Vukotić said.
The automation process, he emphasized, is unstoppable.
“Automation is meant to provide monitoring and control. To control something, you first need to ensure monitoring. Control primarily involves receiving telemetric data, which includes the signaling of switchgear positions and measurements at network branches—such as current, voltage at junction points, and active and reactive power at pickup points,” Vukotić explained.
Over the past five years, the introduction of Smart Grid technology has elevated the concept of medium-voltage network automation, allowing for synergy between energy and telecommunications networks. This enables objects within the system to communicate with the central control center and each other, achieving the most advanced automation concept.
These “self-healing” networks can restore power to end users within 30 seconds after a network failure or power loss.
“Our experience has shown that this can be done in as little as eight to 15 seconds for failures in parts of the network where these concepts are applied,” Vukotić emphasized.
When asked about the challenges of implementing this type of automation in Serbia, Vukotić noted the extensive work required, especially considering that existing energy facilities are over 130 years old.
“Before we can begin automation, we must first reconstruct transformer stations, replacing outdated equipment with modern, synaptic blocks in accordance with remote stations to integrate everything into a unified system. These tasks must largely be done during a single shutdown, within a single day, making it a very difficult job for the teams, especially in urban areas where consumers are highly sensitive to power interruptions,” Vukotić said.
The project with Schneider Electric began a year and a half ago and is scheduled to last five years.
“We’ve purchased 600 microprocessor devices for the modernization of transformer stations, and within this package, we have the ADMS software, which ensures the full integration of the software solution with the equipment we are integrating into the system,” Vukotić stated.
This year, 400 modern medium-voltage RMU (Ring Main Unit) blocks are being delivered and installed across the country. These blocks combine all the functions of modern medium-voltage installations with integrated remote stations that provide remote monitoring and control of the network, while also applying local automation functions.
Instead of long searches, the system now provides real-time information to the dispatch center about direct faults and outages.
The complexity of the project is reflected in the fact that the installation of RMUs is accompanied by extensive technical documentation, including before-and-after photos of the installation, tons of delivered equipment, and data measured in gigabytes.
The scale of the project is underscored by the fact that preparation began back in 2017.
Representatives from each distribution area selected transformer stations nearing the end of their operational lifespan, based on which a plan for installing 400 modern medium-voltage facilities in the first phase was created.
For the Kraljevo Distribution Area, 103 installations were planned, for Belgrade 101, for Novi Sad 50, for Kragujevac 70, and for Niš 74 installations for the first phase.
The entire project will involve the installation of a total of 1,850 modern facilities over the course of four years, improving the reliability of electricity supply and creating conditions for faster responses in case of power outages, with reduced on-site crew engagement.
An important part of this project is the development and expansion of the telecommunications system. It involves the delivery and installation of telecommunications equipment from Schneider Electric, enabling the swift and efficient transmission of all process information relevant to the operation of the electricity distribution system, such as indications, alarms, switchgear statuses, and measurements to higher-level control centers.
The installation of remote stations is planned for 30 targeted transformer stations in the distribution areas of Novi Sad, Kraljevo, Kragujevac, and Niš.
Automation and modernization of the distribution system are necessary due to new requirements arising from our legislation, as, in the future, the market will include not only electricity consumers but also new actors such as producers, aggregators, and other forms of consumers and producers, which will demand greater flexibility.
Elektrodistribucija Srbije, as the operator of the distribution system, supplies electricity to more than 3.8 million users across the country.
This state-owned company manages and maintains an electricity network totaling 168,000 kilometers, with over 37,000 transformer stations.
The EDS network is four times longer than the circumference of the planet Earth.
