| 摘要 |
<p>CONTROL METHOD AND SYSTEM FOR A HIGH VOLTAGE DIRECT CURRENT SYSTEM In an HVDC system, two converter stations, each of which has two converters to operate as a rectifier or an inverter and are connected in cascade, 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 the actual current flowing in the HVDC system when the converter operates as a rectifier, and is 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 already 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 for a predetermined period. This provides an improved control method which can suppress the increase of reactive power required by the converters when the operation mode of the HVDC system is changed.</p> |
