This paper describes the modelling and simulationof offshore wind power plants (WPP) connected to the onshorepower system grid by VSC based HVDC transmission. Offshorewind power plant is modelled with several wind turbinegenerators connected to two separate collector buses with theirown plant step-up transformers. VSC’s are modelled using idealIGBT switches supplied by the gate pulses from their respectivecontrollers.A sequence of operation has been simulated from the startingup of the VSC-HVDC transmission, energizing the offshore gridand subsequent synchronization of the individual wind turbines.Simulation of power ramping up and down as well as steady stateoperation has been demonstrated. As an additional case, theprimary reserve control logic has been implemented andsimulated in PSCAD model.