Power flow unsolvable cases adjustment method based on grid static voltage stability

The unsolvable power flow problem is one of the basic issues in dispatching automation, which frequently appears in the process of grid mode planning and Optimal Power Flow (OPF) analysis. To deal with this problem, a practical adjustment method based on grid weak point is proposed in this paper. This method use “lower power injection” method to calculate a similar power flow solution which also the system maximum load level in unsolvable case. According this solution, the system weak point can be found by the index based on local system operation parameters and external equivalent system model. Combined with sensitivity analysis to reschedule the active power of generators and reactive power compensation devices, so as to make the system maximum load level increase, eventually get the system power flow solution at the original load level. This method overcome the large calculation of optimize algorithm in unsolvable power flow problem and can be applied to large practical grid. In the meantime, this method has clear physical interpretation, operator can be involved during the process, have great value in application. The method is tested on IEEE14 nods system.