Fast redefinition of HVDC converter power set points based on local HVAC and HVDC disturbance identification and a priori HVAC/HVDC optimization

Inhalt:
Future meshed HVDC grids will not participate automatically in significant power flow changes of the interconnected HVAC grid, since the power exchange between both grids will be fully controlled by VSC converter stations. Eventual equipment trips in both grids may cause congestions which can be solved by immediate action i.e. adaption of converter power set points. Such scenarios can be highly time critical, leaving no time for a coordinated recalculation of converter power set points by a central control unit. Equipment overloading or violation of stability criteria might lead to further equipment trips or even cascaded blackouts. This paper proposes a methodology to overcome this challenge. It is based on an optimal set-point adaption for critical tripping scenarios calculated prior to a fault. Optimal set points for all considered fault scenarios are stored locally at each converter station. Continuous local measurements are used to identify critical equipment trip incidents in both the HVAC and the HVDC grid. After successful identification of such scenarios, the converter control applies the pre-calculated power reference value. As such, an optimal reaction towards critical equipment trips can be achieved in a very short period of time without time critical communication or calculation. The developed methodology is presented and evaluated in different HVAC and HVDC tripping scenarios.