Master controller for offshore wind power and hybrid grids

Abstract

Offshore power generation and transmission re-quires longsubsea cables. When using AC, the in-ductance of the cablesresults in reactive power that contributes to the load ofthe cables and increases the voltage at busbars. At thesame time, offshore power systems are becoming increasinglycomplex. They are evolving from dedicated collector gridsand transmission cables for wind farms through shared useof transmission cables by multiple wind farms to hybridoffshore grids that connect wind farms to multiplecountries.This paper discusses operational challenges of off-shoregrids and how they are solved with a model-based mastercontroller that solves optimal power flow problems inreal-time.The Kriegers Flak Combined Grid Solution serves as example.It transports wind power from the four offshore wind farms(Baltic 1 and 2, Kriegers Flak A and B) with a totalcapacity of 950 MW to shore. Additionally, it promotesenergy trade between Germany and Denmark. At the heart ofthe connec-tion of these two energy grids through theBaltic Sea there is a Master Controller for InterconnectedOperations (MIO). Based on a Modelica model and using thePowerSystems library, it solves several state estimationand optimal power flow problems in real-time. MIO isimplemented as geo-redundant system with ABB AbilityTMOPTIMAX® and System 800xA.