抄録
This is the development report for our new type relay systems, Islanded System Automatic Synchronizer (ISAS) and the predictive step out prevention relay system using power flow parameters.
ISAS is a kind of device for self-healing. It performs emergency system re-synchronize operation automatically when the islanded system is separated from the main grid. TEPCO applied some ISAS devices in Tokyo metropolitan area and resulted that reliability in the area was much improved.
The predictive step out prevention relay system mentioned above is a kind of special protection scheme, which predicts generator step out and calculates how much amount of generator should be tripped to stabilize the power system when the fault on the transmission lines is detected. A New predicteve step out calculation algorithm using power flow parameters was developped so that it can be applied for the complex power system. TEPCO applied the new relay system to the area where TEPCO's criteria was not satisfied due to transient instability problem and resulted that the stability was improved enough to meet TEPCO's criteria.
