Dynamic reactive power optimisation of UHVDC converter station considering coordination of synchronous condenser and system filtering requirements

The reactive power compensation of large-capacity synchronous condensers in a ultrahigh-voltage direct current (UHVDC) converter station is not yet fully utilised, and there is no method for achieving effective coordination between synchronous condensers and DC systems. To realise their coordinated control of reactive power and voltage, a dynamic reactive power optimisation model that considers the coordination of synchronous condenser and filtering requirements of system is proposed in this study. The model considers the constraints of the variable steady reactive power capacity of synchronous condenser by taking into account its dynamic reserve demand, the minimum filter capacity of the system, and the switching sequence of AC filters and shunt capacitors. The model is solved by a two-stage hybrid intelligent algorithm based on the interior point method and the differential evolution algorithm. Further, the effectiveness of the proposed method is verified by the example of a UHVDC sending converter station in Northeast China. The simulation results show that the proposed model can greatly reduce the number of times discrete devices enter operation in a converter station under satisfying the dynamic reactive power reserve of the synchronous condenser, providing a basis for the coordinated optimal control of synchronous condensers and DC systems.