The following summarizes the survey and discussion in the meeting for the black start:
The restoration process after a blackout is typical in the following:
– The first choice in the restoration procedure is to get start-up power from neighboring control when available.
– In parallel with that restoration, black start (BS) units energize HV lines toward non-BS units and isolated systems in the control area.
– In that process, each system, including black start units, enlarges while picking up customer load.
In the above typical recovery process, RES plays the following essential roles as BS
– As black starters, pumped storage and large-capacity hydropower account for the majority.
– As kick starters, small-capacity hydropower account for the majority. Regarding RES, there are some attempts to restore local load independently using grid forming inverters (PV, Wind), but this is currently under research and development.
On the field side, PV and wind power can only reconnect the grid after guaranteeing a certain number of synchronous generators to avoid grid instability.