Transient voltage dip analysis using the transient energy function method

It is shown that the transient energy function (TEF) method provides a fast approximate approach to voltage dip computations. The TEF method is used to predict the stability of a power system after a disturbance has occurred. The results of application of the technique to test power systems confirmed that the voltage dips predicted by the TEF method compare well with the values from time domain simulation techniques. An interesting observation is the discrepancy between the two time simulation programs. One of the programs used smaller values of network solution tolerance and solution time step as compared to the other time simulation program. The TEF results showed a consistent pattern of voltage behavior (i.e., the predicted values were lower than the time simulation values). Where there was a discrepancy between the two results, the error was on the conservative or safe side