CONTROL OF VOLTAGE SOURCE CONVERTERS

摘要

This application relates to methods and apparatus for controlling a fault blocking voltage source converter (VSC) apparatus, e.g. a fault blocking VSC (200, 300) with one or one more full bridge cells (204) or a combination of VSCs (1201, 1202) with fault blocking capability. In the event of a DC side interruption, such as a DC side fault, the method involves operating (403, 404) the voltage source converter apparatus after identification (401) of the need for the DC side interruption to extract at least some electrical energy from the connected DC system to the VSC. At least some of the energy extracted from the DC system may be transferred to AC system. Once sufficient energy is extracted from the DC system the VSC may be isolated from the DC system and the voltage source converter apparatus may be switched (406) to a blocked state. Thus rather than instantly switch a fault blocking VSC to the blocked state on detection of a DC side fault the VSC is continued to be operated, and in a manner to transfer at least some energy stored in the DC system to the AC system before blocking.