Dynamic Capacity Increase Technique For Overhead Transmission Line Based On-line Sag Monitoring

Line sag is an important parameter in the phase of system planning and operating.The height of sag impact the security and stability of the overhead transmission linedirectly. Insuring power system is security, study the relationship between transmissioncapacity, conductor temperature and line sag is a very practical problem. On the basis ofthe study of transmission capacity, considering a new method which is based on ling sagto improve the permissible operating temperature of conductor, then improve thecapacity of the transmission line, and improve transmission capacity. Introduce somemethod to measure line sag, and put forward some new method. This paper summarizesthe mathematics models of these three parameters, get the equation of current,temperature and sag. Using actual data, by Matlab nonlinear regression, we can get thecoefficient of the mathematics model, and check the error margin. At the end, give someviewpoint of line sag to estimate the transmission capacity.