Improvement of power flow convergence using switched shunt jacobian

It is not easy to converge power system planning data for real system. Load level is set by load forecast and real power output of generator is adjusted unit commitment. Power flow analysis for these planning data is hard to converge. Most reason of power flow diverse is imbalance of reactive power. The reason of power flow diverge in planning data is reactive power imbalance. Terminal voltage of the generator is dominant for generator´s reactive power output. Mostly terminal voltage of generator is fixed. Reactive power of generator is not adjustable. As a result, the switched shunt is major supplier of reactive power in power system. In traditional switched shunt control, switched shunt step up and down depend on controlled bus voltage. But power flow voltage goes infeasible already. This switch shunt control in power flow analysis for the planning data is not adequate. This paper propose new switch shunt control algorithm using shunt jacobian. New switch shunt admittance is calculated from bus reactive powers mismatch and shunt jacobian. Switch shunt control is applied at first step of power flow to prevent voltage goes low already. When apply proposed algorithm to the Korean real power system planning data. We have good effect to power flow converge with a reasonable voltage level.