The Enhancement Effect of Large Capacity Synchronous Condenser on Critical Voltage of AC System for Commutation Failure

The synchronous condenser can provide rotating reactive power and improve voltage level effectively. This paper analyses the relationship between AC system voltage and commutation area of commutation failure at first, deduces the critical voltage of AC system corresponding to unsuccessful commutation of DC, calculates the critical voltage of typical engineering with three-phase fault for commutation failure. The computing platform of UHV power system with large capacity condenser and actual DC simulation model is established by taking an actual project as an example. The AC failure is calculated at a 1ms time interval, and the critical voltage corresponding to unsuccessful commutation failure is obtained. In the end, the theoretical results are compared with the critical voltage obtained by the simulation platform, and the theoretical and practical engineering results are mutually verified, which has a strong theoretical guiding significance for installing synchronous condenser to prevent the commutation failure in power grid planning, scheduling operation, structural optimization.