Research On Distribution Network Optimization Considering Integration Of Distributed Generators

In order to satisfy the growing energy demand of human society and reduce thereliance of economic development on the fossil fuels, the renewable energy, with the relatedtechnology, has been rapidly developed. Applying the environmentally friendly distributedgeneration technologies, especially to utilize the renewable energy based distributedgenerators (DGs) such as the wind turbines and the photovoltaic cells, is of greatsignificance to improve the efficiency of energy utilization and reduce the carbonemissions.However, the integration of distributed generators in a large scale may influence manyaspects of the traditional distribution systems such as the operation, the planning and therelay protection systems. Although by far many researchers have obtained a lot ofmeaningful results in dealing with the influences mentioned above, there are still someaspects that need to be further studied including the model construction, the controlstrategies and the evaluation methods.In view of this, this paper conducted the researches on distribution networkoptimization considering the integration of distributed generators and the content involves1)characteristic analysis of the interaction between DGs and distribution networks;2)dynamic multi-objective Volt/Var control and optimization in distribution networksconsidering distributed generators;3) optimal DG allocation method consideringuncertainties and requirements of different investment entities and etc. The research workand the main achievements in the paper can be illustrated as follows.The influences of the DG integration to the distribution system were analyzed in theaspects of static voltage deviation, network loss, relay protection system, power supplyreliability and power quality. The influence mechanism of static voltage deviation wasdetailedly studied and the corresponding voltage control measures were provided.In the field of dynamic multi-objective Volt/Var control and optimization indistribution networks considering distributed generators, the mathematic models wereconstructed and the reactive power adjustment capability of DG was included in theVolt/Var control and optimization as a continuous variable. By utilizing the parallel searchfeatures of intelligent algorithm, a heuristic strategy on dealing with the discrete controlvariables was proposed to ensure the constraints of maximum control number andmaximum action number during the optimization process. The simulation results show thatwith the increasing amount of DGs integrated to the distribution network, the action number of the traditional Volt/Var control equipment tends to rise in order to guarantee thesafe and economic operation of the distribution system. With the reactive powercompensation provided by the DGs, the power loss and the static voltage deviation of thedistribution network can be reduced and the system operation indexes can be optimized.When the distribution system confronts with the high penetration of DGs, the node voltagecan be kept in a safe and reasonable range by the reactive power regulation provided by theDGs.In dealing with the different investment entities of the DGs, namely the distributionnetwork operators (DNOs) and the customers, two optimal DG allocation models wereestablished according to the characteristics of both the DNOs and the customers. In order toreduce the uncertainty influences during the allocation optimization process, the LatinHypercube Sampling based Monte Carlo simulation Method (LHS-MC) was adopted inobjective function calculation. After obtaining the robust solutions of different models, anintegrated method simultaneously considering the different requirements of both DNOs andcustomers was proposed. The simulation was conducted on the33-bus distribution systemand the results validate the constructed models and the proposed methods.