| Summary: | 碩士 === 國立臺北科技大學 === 電機工程系所 === 99 === This thesis aimes to study the switching surge characteristics under the operations of gas-insulated disconnecting switches (GDS) in the typical outdoor switchyard of power plant whose air breaking switches (ABS) were replaced by GDS. The study mainly focuses on the very fast transient overvoltage (VFTO) characteristics and their affection’s assessment for the 345kV switchyard in the typical power plant of Taipower system. First, the model of the whole switchyard is constructed by the alternative transient program (ATP). Then, the surge voltage variations are simulated with respect to open operations and close operations of various GDS at different locations, in which energized and de-energized states of other non-operated bays of switchyard are considered. Two switch modes of GDS operation namely three-phase synchronous operation mode and non-synchronous operation mode are also taken into account. In addition, the VFTO due to the case of GDS switching when residual voltage (trapped charge ) on the de-energized bus are analyzed too. At last, based on the switching surge voltage analysis results, the detrimental affections of switching surge voltages on the related requipments are evaluated by comparisons between analyzed switching surge voltages and the toleranable basic switching surge insulation level (BSL) and basic impulse insulation level (BIL). The evaluation results show that no switching surge voltage will over BSL and BIL of related equipments under normal operation of GDS, but the VFTO resulted from GDS switching when the inverse residual voltage on the de-energized bus may cause to damage the weaker equipments, e.g. bus potential transformers (BUS-PT). For those weaker equipments, the protection measures should be enhanced. This thesis can provide useful reference for the future improvement works.
|
|---|
