Mapping and analysis of the reactive power balance in the South Zealand part of the Danish transmission system network

In this paper, the reactive power balance of the Zealand part of the Danish transmission system network (DK2) will be investigated and the specific finding and recommendation, with specific emphasis on the southern part of the DK2 network, will be presented. The investigation used Energinet’s full scale PowerFactory model of DK2 together with a complete data collected from Energinet’s SCADA system over a period from 01-01-2016 to 20-08-2017.The etwork in Denmark has slowly changed from a predominantlyinductive-, to a predominantlycapacitive network. These changes have a pronounced effect on the reactive power balance, in the transmission network. Energinet is the only Transmission System Operator (TSO), and the distribution network has been split into different Distribution System Operators (DSOs) with a superficial boundary of 100kV.The analysis in this project was done by investigating the reactive power flow in steady state, this means that there will not be done any dynamic analysis, and there will only be qualified assumptions to this regard. The traditional way of analysing the reactive power requirement, is to calculate an upper limit for the reactive power flow between the distribution network and the transmission network. In this paper the focus will be on more holistic approach where the QV-analysis technique will be used to determine the amount of needed compensation and the best possible location on where the reactive compensation needs to be performed.