Electromechanical Transient Modeling of UHVDC Reactive Power Auto-Control

In view of the lack of modeling for UHVDC reactive power control in power system security analysis, the results of online security early warning and off-line analysis were not accurate for the voltage and output power at the DC near-zone AC and DC faults. Based on the reactive power control logic in DC control system, this paper proposed the UHVDC reactive power control simulation method which was suitable for power system transient security analysis, and unified consideration the reactive power control and over-voltage control for reactive power compensation. It was realized that the automatic simulation of DC power control during the transient simulation process to simulate the action condition, delay and the action object of reactive power control. It effectively improved the accuracy of the online early warning assessment. At the same time, the results of a real power grid showed the correctness and effectiveness of the proposed methods.