Introduction  Under the existing converter station reactive power compensation scheme, the synchronous condenser only provides transient reactive power support, and the AC (Alternating Current) filter undertakes steady-state reactive power compensation and adjustment tasks, with a lack of coordination scheme between the two and insufficient economy.

  Method  On the basis of ensuring the dynamic characteristics of the synchronous condenser, based on the operating characteristics of the DC (Direct Current) sending and receiving end systems, firstly, a reactive power optimization scheme for the converter station was proposed, in which the regulator was used to replace a part of the part of the AC filter capacity with the regulator, and both participated in steady state reactive power compensation. Ubsequently, a two-layer reactive power adjustment strategy for the converter station was proposed according to the sequence of actions. The first layer of reactive power adjustment was undertaken by the synchronous condenser, which was realized by adjusting the output within the range of steady state operation. The second layer of reactive power adjustment was started after the first layer of reactive power adjustment, and the AC filters were switched on group by group for reactive power adjustment until the reactive power adjustment requirement of the converter station was reached. Finally, a LCC-HVDC (Line-Commutated Converter High Voltage Direct Current) system simulation model was built in PSCAD for simulation verification.

  Result  The simulation results show that the reactive power compensation scheme and the two-layer reactive power adjustment strategy proposed can optimize the number of AC filter configuration groups in the converter station, reduce the frequency of AC filter switching in the converter station.

  Conclusion  The proposed scheme achieves optimization of the existing LCC-HVDC converter station reactive power compensation scheme and reactive power adjustment strategy.