Research On Strategy For Undervoltage Load Shedding And Underfrequency Load Shedding Based On Monte Carlo Algorithm

Monte Carlo algorithm is a calculation method to estimate the values and solve unknown variables by a random simulation test with random numbers. The basic idea is that when a problem happened in a probability of some random event, which can be estimated through the frequency it occurs, or a problem solution equal to specific numerical characteristics of a random variable. This algorithm is based on the theory about probability and statistics. The solution can be related with a certain probability model, thus it can be solved in a approximate solution by a computer statistical simulation. Monte Carlo algorithm is both continuity-free and differentiability-free, which is suitable for mathematical problems with a high dimension such as a power grid.Under Voltage Load Shedding as well as Under Frequency Load Shedding is an important way to the third line of defense in order to maintain the power system stability, and is also the load distribution scheme in future for the power system operation mode, which is uncertain. Monte Carlo method takes account of a variety of random factors in power system. With its strong adaptability, the computational complexity has little negative influence on the speed of solving such problems. Moreover, the convergence of the algorithm is in the sense of probabilistic convergence, so that the problem's dimension increasing does not slow the converging speed. While programming in PSS/E, this algorithm also saves the storage space a lot. Monte Carlo algorithm is applied in the strategy for both Under Voltage Load Shedding and Under Frequency Load Shedding in this paper, some domestic real power network is simulated with this algorithm, and the results shows that, compared with those traditional algorithms. This algorithm is more efficient in maintaining power system stability and optimizing the cost of load shedding.