Study On Thermal Load Capacity Of Overhead Transmission Lines Based On Meteorological Data

With the sustained and rapid development of our country’s economy,the demand of electric power energy is increasing.At this stage,because of the new energy such as wind,water,light as the supplement of the traditional coal-fired power,generating capacity has been greatly improved.However,the distribution of energy in China is not balanced.Besides,the construction of transmission line is in a serious lag compared with the improvement of power generating capacity.It is urgent to improve the transmission capacity of transmission network.The transmission capacity of transmission lines is mainly limited by the operating temperature of the transmission line,and most of the current evaluation methods for the thermal load capacity of the transmission line are based on the static thermal rating method under severe environmental conditions.Because the static thermal rating method is conservative,in recent years the development of dynamic thermal rating technology has developed to achieve the mining for transmission line transmission capacity,but the dynamic thermal rating of technical equipment investment and operation and maintenance cost constraints,the dynamic thermal rating technology has not been widely used dynamic.In this thesis,by using the IEEE heat balance equation of overhead transmission,the environmental parameters that affect the operating temperature of the overhead transmission line are analyzed.As for the problem of high cost the application of dynamic thermal rating technology,a new method of using the GRAPES_Meso mesoscale numerical weather prediction technology in the overhead transmission line heat capacity evaluation and based on geographic information system,along with GIS to obtain the overhead transmission line accurately forecast meteorological parameter is put forward.Then replace the dynamic thermal rating of environmental monitoring equipment,and finally realize to forecast the heat capacity of transmission line.Because of the complexity of transmission line and spatial distribution of the meteorological conditions along the transmission line,the actual parameters of the lumped parameter line equivalent circuit model cannot accurately represent the transmission line;this thesis put forward non-uniform distributed parameter model of transmission line based on dynamic thermal rating thermal,and then establishes the power flow analysis model based on the actual running temperature of the transmission line;by the case analysis.Respectively at different times and considering the transmission line parameters of the spatial distribution characteristics of a simple grid for power grid work out power flow analysis.The results show that the simulation results of the proposed power flow analysis model are quite different from those of the commonly used nominal temperature grid parameters,show that this power flow analysis model for thermal power grid transmission line load capacity evaluation is more accurate and has greater practical significance.Analysis of meteorological data of overhead transmission line heat capacity based on the proposed model,power flow and transmission lines based on actual operating temperature,can improve the transmission reliability and efficiency effectively,mining potential thermal load transmission network,in addition improve the utilization of new energy.