The Kriegers Flak Combined Grid Solution (KF CGS) is the first hybrid‐asset project utilizing an offshore HVAC/HVDC interconnector for large offshore wind power plants between Eastern Denmark and Germany in the Baltic Sea. In total, the KF CGS utilizes above 520 km HVAC cables. On the Danish side, above 200 km 220 kV cables are arranged into a meshed offshore transmission grid (MOG). As the cables approach the critical length, the reactive power generation depends on the active power transfer. In order to maintain good voltages in the MOG and wind power plants, on the Danish side, the control is realized by an automatic voltage regulation and reactive power control (AVR/RPC) of several switchable and variable reactors and transformers with tap‐position controllers, and the Wind Power Plant Controllers (WPPC); on the German side, the voltage control is achieved by the HVDC Back‐to‐Back converter, WPPC, and part of the Optimal Power Flow (OPF) by the Master Controller for Interconnector Operation (MIO). This paper presents the proposed coordinated voltage and reactive power control and assets of the HVAC MOG on the Danish side of the KF CGS interconnector. The efficiency and constraints of the proposed coordinated control scheme of the KF CGS at fluctuating voltage and reactive power in both ends of the MOG has been presented by simulations using the entire set up of the 220 kV AC MOG with the validated model of the AVR/RPC, the models of the 220/33 kV transformers and their control, and the models of the KFA and KFB WPPC.
|Journal||I E T Renewable Power Generation|
|Number of pages||14|
|Publication status||Accepted/In press - 2020|