Distributed Generation Planning Based On Cost-benefit Analysis

Distributed generation (DG) is expected to play an important role in the emerging power system, due to the benefits of the flexibility, shorter construction period and environmental friendliness. Different type of resources and technologies are used to serve energy to power system. System and load point reliability indices are normally improved if DG is installed in distribution network. On the other hand, DG has some specific characteristics which distinguish it from conventional generating units. Some renewable sources such as the wind and the solar energy are restricted by natural weather conditions which have the random, intermittent strong features. Power quality issues, islanding operation and voltage control problem are among troublesome impacts of DG on power system, and the extent of the impact is closely related with the location and the capacity of distributed generation. In view of the distribution network planning and the distribution generation's characteristics,impacts of DG implementation on distribution system reliability are investigated in this paper ,based on the theory of cost-benefit basis using a distribution test system. A reliability model for DG is developed and an analytical probabilistic approach is proposed for this purpose. Impacts of different parameters such as the production costs, environmental costs and comprehensive benefit, are included in the analysis.In order to effectively implement the reliability improvement of distributed network which contains DG, an appropriate model is required to be developed in order to assess impacts of DG on reliability indices. Then an islanding algorithm is outlined while the fault occurs in distribution network with the distribution generation, which its reliability is well evaluated. Besides, a linear interpolation method is proposed to accomplish the estimated of the customer interruption cost, which could successfully quantify the degree of reliability improvement level for economic indicators. In this paper, the environmental cost is mainly presented from the environmental value of the major pollutant and their fines. Finally, it will be counted into the unit cost of electricity generation, and thus the cost model of the distributed generation will be improved accordinglyWith the data generated from practical examples, it demonstrates that the method proposed in this paper will deduce the loss and the customer interruption costs effectively, and also improve the reliability of distribution network. Comparisons between the planning obtained and the traditional method are made to verify the accuracy of the planning proposed in this paper, which has the advantage of the economical, effectively, and reasonable. It can be also seen that the former planning can achieve significant environmental benefits and social benefits.