Research On Available Transfer Capability For AC/DC Hybrid System Considering Uncertainties

With the formation of AC/DC hybrid system in our country, in the power market environment, the research on Available Transfer Capability (ATC) for AC/DC hybrid system has important theoretical significance and practical value. This paper establishes a ATC model and researches on ATC for AC/DC hybrid system considering uncertainties, such as equipments (including generator, AC line, DC line and transformer) failure, load fluctuation, the whether and so on.A novel method is proposed to calculation ATC based on Markov chain and fault ranking method. Markov chain is used to establish the prediction model of the AC system and DC system. Taking into account the probability of failure, failure consequences and the position of load and source points, select the fault which has the greatest impact on the system by the use of a fault ranking method. And then, Use interior point method to calculate the ATC of each state. According to the probability of each state, get the ATC expectation values and estimates the ATC continuous curve. Gain more accurate information on ATC.Evaluate ATC for AC/DC hybrid system. Construct the evaluation index from the abundant sexual for AC/DC hybrid system. And a series of ATC assessment indices are defined, including the expected value, variance, variation coefficient, max, min, probability of ATC equal to zero, probability of ATC not satisfied, et al. Use non-sequential Monte Carlo simulation method to establish the state forecast models of the AC and DC systems, and simulate the possible running states of system. Establish the ATC calculation model based on DC power flow model, which is used to calculate the value of ATC at each simulation state fast. Finally, the ATC assessment indices can be obtained. The approach can provide important information for power system security economic evaluation.