Until 2014, Troitse-Pechorsky, Ust- Kulomsky and Kortkerossky Districts in Russia were powered by single-circuit lines. Any damage in the network led to the brake down electricity supply to consumers of one or more areas. With the line "Voivozh - Pomozdino" the “energy ring” was created, which now provides a second power supply to the three districts. To exploit the potential of the line in full there was a need to transfer the large capacity of power and automatic voltage regulation. To solve this problem, “IDGC of the North–West” (international distribution grid company) decided to install at Ust-Kulom substation a reactive power source RPS(C)-110/10/10 consisting of the CSR and capacitor bank.
Daily schedule voltage variation had reached 5.5 kV on 110kV buses, which had a negative impact on the switching equipment, increased wear of the voltage regulators and the stability of electric power in general. Also worth mentioning is that the increased voltage of 110kV buses reached 122.5 kV. Fluctuation of the grid voltage before substation modernization had been 5.5 kV, which had been almost 4.7% of grid voltage. After modernization fluctuation of voltage did not exceed 0.3%.