Research On Load Supplying Capability Of Active Distribution Network Considering Economic Dispatch

With the continuous maturity of distributed power generation technology and the growing increase of distribution system automation level,the problem of renewable energy consumption and passive dispatching operation mode existted in traditional distribution network make it hard to meet the request of development.The change comes into being from traditional distribution network to active distribution network.Active distribution network as future smart grid development's advanced mode could integrate electric power resources by the strategy of global optimization.Furthermore,distributed generations assessed in active distribution network can be coordinated by active control and active management.Compared with traditional distribution network,active distribution network has flexible dispatching strategy and diversified methods of generating electricity,and these characteristics influence on distribution system security and reliability.Load supplying capability is an important index which could reflect operational security and reliability,and it's also an important reference for dispatching operators to estimate operating state and formulate dispatching strategy.Now,traditional solving methods of load supplying capability does' t consider the actual operation characteristics of active distribution network,and the result can't reflect the actual condition accurately.This paper conducts a study on key factor of load supplying capability on the basis of distribution network assessed distributed generation.A bi-level load supplying capability optimization model considered economic dispatch in active distribution network is proposed,and it's considered that uncertainty of non-schedulable distributed generation and active distribution network's operation characteristics.In addition,taking advantage of chance constrained programming,the output power of non-schedulable distributed generation is formulated as random variable and the constraint conditions are formulated as constraints condition of opportunity.In model,the upper model is the load supplying capability problem to obtain maximum load,and the lower model is the economic dispatch problem to determine the active outputs of schedulable distributed generation according to economic dispatch principle.This model proposed by the paper can realize that the active output of schedulable distributed generation is dispatched economicly with the process of load growth in each running point.Finally,the load supplying capability which meets economic operation requirment in active distribution network is obtained.During the process of model solving,particle swarm optimization arithmetic based on Monte Carlo simulation is adopted considering the random variable in bi-level model.And then,repeated iteration between the upper model and the lower model is to get optimal solution by alternating iterative algorithm until meet required precision or iterative times.At last,the modified IEEE-33 bus distribution system is as test system to figure up the proposed model.The rationality and availability is verified by compared the results,and it is necessary to take the influence of ecnomic dispatch into account reasonably during calculating load supplying capability in active distribution network.