Research On Multi-objective Distribution Network Planning Considering Life Cycle Cost

Power industry is the basic industry of the national economy， and thedistribution network is a part of the power industry which connects directly with theuser, so it is important to make the distribution network planning scientific andrationally to improve its economy and reliability for the construction of the powersystem as well as the economic and social development. Based on the previouswork, this paper studies the network planning from the model and algorithm aspects,and proposes some new models and algorithms in order to provide some help to thefuture distribution network planning work.In terms of model, this article applies life cycle cost (LCC) technology to thedistribution network planning, establishes the LCC models of main distributionnetwork equipment, and focuses on the calculation method of power outage cost.The paper proposes a distribution network reliability indicator--network risk indexwhich can reflect the rationality of the distribution network structure; Amulti-objective distribution network planning model is established, which takes theLCC and network risk index as its objectives;In order to count power outage cost, the uncertainty of the load and the impactof the reliability centered maintenance (RCM) for failure rate are considered. Thefunctional relationship between failure costs, the load type and failure time is given.The probability load is applied to the sequential Monte-Carlo method to get a moreaccurate power outage cost of the plan.In terms of algorithm, this paper gives a deep research to theBiogeography-based Optimization (BBO), and proposes a new improved strengthPareto evolutionary algorithm which is based on BBO. The technique for orderpreference by similarity to an ideal solution is used to sort the individuals in Paretofrontier, and the optimal solution is screened out.With the research of the Non-inferior solution concept, considering thedistance and dominance relationship between the solutions in the solution space, anew fitness function is proposed to improve the search ability of the Paretoalgorithm for the non-inferior solution. Based on node incidence matrix, a networkrepair algorithm is designed, which can find and repair isolated node, isolated chainand the closed loop to meet with the requirement of grid radial.Finally, a real part of the distribution network in a city is carried out asplanning example. With the given example the distribution network LCC model andmulti-objective model are validated. The results prove the reasonableness of the proposed model and the effectiveness of the proposed algorithm.