The Short-term Planning Of Urban Distribution Network Based On Total Supply Capability

After large-scale constructions of the urban grid for decades, m ost of the city distribution networks have realized a leapfrog devel opment, but a new problem emerges that the load rate in some areas is too high, while too low in many other areas. Hence, the next stage of development of the distribution system should be focused on optimization of the grid struc ture. Moreover, the available land for the power grid is not enough and the cost is extrem ely high. In some areas, there are few resources for substation sites and line corridors. Trad itional planning m ethods are suited to the rapid developm ent of the grid, but it is di fficult to adap t to the cur rent plannin g requirements. In the context of the sm art grid, distribution autom ation will be developed greatly in the future. As the result, the grid has a great potential to run at a higher load level th rough rational optim ization. Duri ng the distribution network reconstruction and planning work, the pow er supply elevation caused by network interconnection and d istribution automation should be taken into full account, and existing networks should be m ade full use of to support the increasing load. In this backgroud, this paper presents a short-te rm urban distribution network planning method based on the concept of T otal Supply Capacity (T SC) and has conducted a preliminary study.First, this paper describes the development of the TSC theroy of the distribution system in recent years and proposes a m ethod to check and reconstruct the bottleneck tie lines automatically to enhance power supply capacity. Based on the N-1 security criterion, this method can integrate the power transfer capacities of both the substation and network, especially suited for the large scaled interconnected distribution network. Through analysis and reconstruction, this m ethod can exploit the power supply capacity of certain regions and make full use of load transfer capacity of tie lines.Then, based on the calculation m odel of the m aximum power supply capacity, this paper proposes a m ethod for load di stribution, which takes into account lo ad distribution constraints, sets the transfor mer loading bala ncing and security as the optimization objectives, redesignes the m athematical model and solves this m odel using Lingo. The N-1 constraints are included in the mathem atical model of this optimal load distribution m ethod, realizi ng the analysis and check for the pow er supply and dem and balancing considering the load distribution. Meanwhile, it can make comprehensive considerations of tr ansformer loading balancing and security.This method is the basis for the power grid optimization and short-term planning. Finally, based on the concept of TSC, this paper proposes a new urban short-term planning workflow and steps. This work flow uses the above load distribution optimization method and expert experience to plan the grid to m eet the future power demand, exploiting the potential power supply capacity and deferring the grid upgrade to solve problem s of t ight available subs tantion site s an d line corridors and save investment of the infraustures.All the abo ve work has been tested in plann ing cases and com pared with traditional methods to prove the feasibility.