To meet increasing flexibility and performance requirements, Estonia’s largest electricity distribution system operator (DSO), Elektrilevi, has chosen ABB’s SSC600 centralized control and protection solution.
Utilities all over the world are dealing with the need to develop their networks due to rapidly evolving changes, such as increasing amounts of renewable energy resources being connected to the grid and the introduction of new energy storage devices.
All this needs to happen without risking the security of the power supply. This means that the protection and control functionality of electricity networks must be enabled to manage continuous changes during the entire lifetime of the network equipment. This poses a tremendous challenge for the protection and control system, as it needs to become more flexible and be able to reconfigure faster.
To meet these challenges and deliver an optimized maintenance process, ABB has introduced ABB Ability™ Smart Substation Control and Protection for electrical systems, SSC600. With this product customers can easily upgrade their protection system’s software via only one entry point which means fewer working hours. The SSC600 solution brings unprecedented flexibility and up to 15 percent savings in life cycle costs can be achieved as it offers an open platform for developing new network functionalities as required.
Elektrilevi supplies 93 percent of the businesses and households in the country with electricity. Maintaining and developing their grid, which includes 60,000 kilometers of power lines and more than 24,000 substations is therefore a significant undertaking. Committed to providing a disturbance-free power supply, the company is keeping up with technological progress and making investments into developing an efficient network. In January 2021 a new company, Enefit Connect has been established. Enefit Connect is the main partner for the commission, operation and maintenance of Elektrilevi’s distribution network.
Elektrilevi has now chosen to install the first centralized protection and control solution with SSC600 in a substation in Estonia’s capital and most populous city of Tallinn. The substation built in 1998 is located in the Lasnamäe district near Tallinn airport. It houses medium-voltage switchgear from different generations. There are third party older generation switchgear panels, as well as ABB’s UniGear ZS1 medium-voltage switchgear panels from the end of the 1990s. Both switchgear types have been equipped with older generation ABB protection relays nearing end-of-life. Elektrilevi chose to not only replace, but to take the new approach to network protection and control to reduce protection system complexity and effectively control protection functions.
Inside the substation. Photo courtesy of Elektrilevi. 
Smart substation control and protection SSC600
“Smart solutions are vital when developing the infrastructure of tomorrow. We wanted to be a pilot user of ABB’s SSC600 to learn about this new technology firsthand,” said Rein Aron, Area Manager at Enefit Connect. “It is an interesting approach, as consolidating multiple relays into one device reduces network complexity and offers effective ways to control protection functions.”
In this case, SSC600 is added to an existing installation, which will provide the entire substation with the latest technological developments within protection and control. To ensure reliability the installation has two SSC600 devices; the second one is installed to gain full protection redundancy. Another possibility would have been to use the protection relays already installed as the back-up solution.
Commissioning the SSC600 devices took place in November 2020. “The goal was to test and learn to use the system in a safe manner in a relatively small substation” said Rein Aron. “In our experience the system is logical and easy to use. Also redundancy is great, as the 615 series merging units are easily replaceable and SSC600 can be duplicated for even more reliability, when needed. I already see that we are ready to use this system in our main substations.”
Research and development into centralized protection and control solutions has been going on for decades and attempts to fully integrate control systems were undertaken 20-30 years ago. However, it took until more recent advancements in computing technology and international standards to make it a feasible alternative for modern substations.
“Customers are looking to find alternative solutions to meet the increasing flexibility and performance requirements” said Mika Kukkola, Regional Solution Center Manager, in ABB’s Distribution Solutions division. “The electricity distribution network is a vital services infrastructure, and the investments made in it bring benefits for decades to come. Managing modern power distribution networks with centralized protection and control will help optimize operations and reduce total cost of ownership.”
