Research On The City District Load And Network

Power is an important factor which is a measure of the economic development of city. The scientific and reasonable power grid planning can obtain great social and economic benefits. At present, in urban power, grid power load fluctuates frequently, space truss structure is fragile, power supply is unstable and line toss is high, the electric power facilities is aging, degree of automation is low, power quality is low and so on. These compare with building a strong smart grid which the country put forward to is very large. Therefore, carries on the power grid planning, reforming which according to the construction of planning is imperative.This paper first introduces the urban power grid p planning’s some background and design process,makes a generalization of the system about load forecasting and network expansion planning’s research methods.The load forecast is in preference to the network expansion planning.When we confirm the load distribution and the size in the future,we can have an effective planning to the location and capacity of the substation, the path,model, capacity of the line,the investment and furnish of equipment and so on. The results in a certain extent determine the network expansion.Based on the analysis of the current relatively popular in the engineering about load forecasting’s method,in an area of20kV power load forecasting work,the load density index method is used to obtaining load data from the area,making various tests to the results in order to ensure the correctness of the data.The reasonable layout of power system network frame is closely related to power grid operation mode, the feasibility of the circuit expansion, economic costs, electricity of the security and stability and so on.At the same time, network programming subjects to various constraints.Today, network programming lacks of completely scientific theoretical guidance.Aimed at this phenomenon, this paper studies the trends of the DC power flow calculation method and DC current fault analysis,the model of the maximum transmission power in reliability analysis. Depending on the theory of the circuit in the merging means of short circuit nodes,presenting on the basis of adjacency matrix grid connectivity testing method.Finally according to the established mathematical model, the improved genetic algorithm is applied to the planning network frame,making line construction investment and operation cost minimum as objective function,solving with integer constraint, the safe operation of the constraints,"N-1" accident constraints and so on of the optimal planning problem of grid construction cost,using matlab7.0programming language to write the application, calculating the Garver-6node and district13note power system network example,the calculation results show that the proposed improved genetic algorithm convergence is good and fast.