HVDC simulation的.pptVIP

HVDC 仿真算例分析 Thyristor-Based HVDC Link Description of the HVDC Transmission System A 1000 MW (500 kV, 2 kA) DC interconnection is used to transmit power from a 500 kV, 5000 MVA, 60 Hz system to a 345 kV, 10000 MVA, 50 Hz system. The AC systems are represented by damped L-R equivalents with an angle of 80 degrees at fundamental frequency (60 Hz or 50 Hz) and at the third harmonic. The rectifier and the inverter are 12-pulse converters using two Universal Bridge blocks connected in series. Open the two converter subsystems (Rectifier block and Inverter block) to see how they are built. The converters are interconnected through a 300-km line and 0.5 H smoothing reactors. The converter transformers (Wye grounded/Wye/Delta) are modeled with Three-Phase Transformer (Three-Windings) blocks. The transformer tap changers are not simulated. The tap position is rather at a fixed position determined by a multiplication factor applied to the primary nominal voltage of the converter transformers (0.90 on the rectifier side; 0.96 on the inverter side). From the AC point of view, an HVDC converter acts as a source of harmonic currents. From the DC point of view, it is a source of harmonic voltages. The order n of these characteristic harmonics is related to the pulse number p of the converter configuration: n = kp ± 1 for the AC current and n = kp for the direct voltage, k being any integer. In the example, p = 12, so that injected harmonics on the AC side are 11, 13, 23, 25, and on the DC side are 12, 24. Rectifier and Inverter Steady-State Characteristics and VDCOL Function In normal operation, the rectifier controls the current at the Id_ref reference value, whereas the inverter controls the voltage or gamma at the Vd_ref or Gamma_min reference value. The Id_margin, Vd_margin, or G_margin parameters are defined in the inverter dialog box. They are set at 0.1 pu, 0.05 pu, and 1.0 deg., respectively. The system normally operates at point 1 as shown in the figure. However, du