| 摘要 |
<p>A HVDC system has two converter stations, each of which has two converters connected in cascade to operate as a rectifier or an inverter and the stations are connected through a d.c. power transmission line to each other and are connected to respective a.c. power sources through the a.c. power transmission lines. Each converter is controlled depending on the difference between a current reference for the HVDC system and an actual current flowing in the HVDC system when the converter operates as a rectifier, and controlled depending on the output of the constant margin angle control circuit when the converter operates as an inverter. When the converter operation condition is changed, i.e. another converter operates in addition to the converters in operation or the direction of power transmission in the HVDC system is changed, the current reference for the HVDC system is reduced depending on the d.c. voltage during a predetermined period.</p> |
