Calculation And Analysis Of Line Loss Fluctuation Of 10kV Overhead Line

With the massive increase in power load and the rough expansion of the power grid in previous years,the line loss rate of the distribution network remains high.The scientific norm management and calculation methods adapted to the line loss of the distribution network have received more and more attention.How to reduce the line loss of the distribution network and improve its operating efficiency is a subject worthly project The paper mainly studies the calculation of the limit line loss of the distribution network and the influence of the resistance change of the 10 kV overhead line on the line loss calculation.Distribution line loss is one of the important indicators for the economic operation of the power system,reflecting the planning,design and operation level of the distribution network.In this paper,the concept of limit line loss in 10 kV distribution network is improved.The root mean square current method is used to establish the mathematical model of limit line loss of distribution network based on the load constraint equation of the inlet end of the distribution network and the maximum load constraint of the load end,using genetic algorithm and branch subtraction.Small optimization navigation solves the objective function and compares the results,analyzes the maximum and minimum variation intervals and trends of the limit line loss,compares the optimal power values of each load node under the minimum line loss rate,and analyzes the distribution network planning from the perspective of energy consumption.Rationality and direction of improvement.The research shows that the maximum and minimum calculation results of the limit line loss of 10 kV distribution network are in a reasonable interval.The line loss of the distribution network under this topology is within the limit line loss interval,which provides a powerful theory for the power supply company to issue the comprehensive line loss rate index.support.The traditional 10 kV distribution network line loss calculation does not consider the influence of temperature and skin and proximity effects on the resistance value.It is only calculated using the reference value on the overhead line manual.From the engineering point of view,the calculation accuracy meets the calculation requirements of the distribution network line loss,but from the perspective of refinement,the accuracy is difficult to meet.This paper starts with the electromagnetic field simulation of the overhead line of 10 kV distribution network.Using the ansys finite element simulation method to consider the skin effect of the common frequency current,the current density distribution of the conductors in the overhead line is derived,according to the current density distribution and the internal line of the overhead line.The surrounding energy distribution,the internal temperature field of the overhead line is coupled,and the internal temperature field distribution law of the steel-core aluminum stranded wire of the overhead line is established.The variation law of the resistance value of the overhead line of the 10 kV distribution network is studied according to the three laws of heat conduction.Studying the difference between energy density,temperature field and current density distribution of steel core aluminum stranded wire model and steel ring aluminum wire model,based on the simplified model of steel core annular aluminum wire instead of steel core aluminum stranded wire,and considering the power quality problem in steel core The influence of the ring aluminum wire on the loss calculation,including the study of the three-phase voltage unbalance degree under different degrees,the harmonic current at different levels,and the positive sequence negative sequence current on the calculation of the overhead line loss of the 10 kV distribution network,The conclusion of the comprehensive impact of the power quality problem on the calculation of overhead line loss is obtained.As the basis for the power supply company's calculation and management of the line loss of the 10 kV distribution network,it has improved the line loss management level of the power supply company.