**Post: #1**

This paper deals with the methods to find out the margin to restore power system solvability (i.e. how much active and reactive power needs to be reduced so that an unsolvable power system can be brought to a stable operating point). The direction in which we reduce the power is important and is considered in the first method of approaching the closest bifurcation point. In the second method, a minimization technique is adopted to find the active and reactive powers at the buses in the power system if the power system had been operated very close to the boundary dividing the solvable and unsolvable regions, without actually operating at that point. In another method, prediction of the reactive power injection at certain buses to come to a solvable region from an unsolvable region is also done. The method to find the margin to voltage instability from a solvable region by using the continuation power flow method is an accurate method. This is because the modified load flow equations can converge near the critical point. The cost function method to find the margin to voltage stability from an unsolvable point is also an accurate method as it is a minimization method and there is no problem of divergence. The only constraint could be that the program cannot be tested for very large systems.