MVA constraint handling method for unified power flow controller in loadflow evaluation

The unified power flow controller is a promising power electronics device capable of providing complex control for power systems. The device can control the series power flow and also provide reactive power support to one node. Along with its complex operation come various operational constraints, which must be modelled within load flow to allow for system studies and analysis. A method for modelling the unified power flow controller´s MVA constraint in the shunt converter is presented. The technique is analogous to the reactive power limit switching applied to generation nodes during the load flow solution. The method enables the maximum shunt compensation to be obtained while satisfying the operational constraints of the device. The method is implemented in the Newton-Raphson load flow method and applied to standard power systems for validation