Abstract

The electrification of several big sectors of society and the increasing share of renewable energy production also means greater demands on the electricity grid. The ability to control and regulate power flow is becoming critical to maintain a stable electricity supply that meets the requirements in place. Large industrial loads are particularly important to manage because they can significantly affect the surrounding grid. The purpose of the report is to analyze the current capacity for reactive power regulation in a small distribution grid and to identify how that capacity can be improved with new regulation capability. The report also aims to analyze how future connections to the grid may affect the need for regulation.

To carry out the analyses, the studied network was modelled in the software DigSILENT PowerFactory. Data for the model was obtained from the software dpPower, which the company uses for grid operation. The model consists of two network branches connected to an upstream grid via separate busbars. The model includes three loads, of which two are heavy industries at voltage levels of 130 kV and 10 kV respectively. The third is a smaller residential area at 10 kV. The new connections analyzed consist of a solar park with battery storage and a data center, all at a voltage level of 130 kV.

To achieve the purpose of the report, four cases were simulated: the base case, regulation using existing resources, regulation using an SVC, and the impact of new connections on the grid. The results show that there is currently no capability to regulate the large fluctuating reactive power flows primarily caused by the industry connected at 130 kV. An SVC connected directly at the industrial load would enable full compensation of the reactive power. This would provide financial benefits compared to the base case, as the network currently faces additional charges when reactive power flows exceed the contracted limits according to current tariffs. The results also show that a future connection of the data center requires the solar park and battery system to be capable of supplying active power. Otherwise, the connection would result in active power demand from the upstream network exceeding the contracted capacity.