Dynamic Reactive Power Coordination Control Method for UHVDC Converter Station

In recent years, UHVDC transmission has developed rapidly. However, large-capacity DC converters generally use semi-controlled devices. The receiving converter station consumes a large amount of reactive power, which is easy to change when the AC bus voltage drops. The commutation failure happened, and more reactive power is absorbed from the AC system, which threatens the stability of the bus voltage. In order to study the dynamic reactive power coordination control strategy of UHVDC converter station, this paper compares the commonly used reactive power compensation equipment, and points out that synchronous condenser (SC) has significant advantages in reactive power regulation. This paper proposes a DC control system and SC coordination control scheme, and simulates the strategy through the electromagnetic transient simulation software PSCAD. The simulation shows that the synchronous condenser can provide continuously adjustable dynamic reactive power support during the change of the system switching filter, avoiding the risk of grid voltage drop exceeding the limit and improving the stability of the AC bus voltage. (paper)