Research On Transmission Line Dynamic Capacity Calculation And On-line Monitoring Technology

In recent years,the electricity consumption keeping growth with the development of the economic and the request on power transmission capacity increasingly.With the constrain of investment by new lines and covering issues such as corridor constraints,line construction is lagging behind.The maximum current carrying capacity of the transmission lines is based on the existing rules that calculated with harsh weather conditions(at the same time meet:ambient temperature 40℃,wind speed 0.5m/s,sunshine 0.1W/cm~2),which increased electric power plant litter and limits the ability to play power transmission,increased electric power plant litter.Transmission Line Dynamic Capacity refers to the real-time calculation of the maximum transmission capacity of overhead lines by measuring environmental parameters.There are some problems about the existing Transmission Line Dynamic Capacity Technology,such as:the large of monitoring parameters,device complicated,less accurate and so on.Aiming at the above shortcomings,it deep analyzes of the relationship of the factors which impact the Dynamic Capacity of transmission lines and researches the mechanism of Dynamic Capacity.Firstly,Thesis analyses the calculation of power in heat balance equation of transmission line and the factors affected the carrying capacity of wire.Then,it compares the existing computing model of Dynamic Capacity Ampacity.On this basis,The dynamic capacity of temperature and ampacity simplified calculation model is proposed,the accuracy and validity of the model are proved through field test.Sag of transmission lines is an important indicator of dynamic Capacity technology.Thesis analyzes the relationship between the sag and stress,temperature and other parameters,compared with the existing calculation model of sag stress real-time measurement.And further put forward the sag calculation model based on ultrasonic ranging principle of LLS.The model can be more accurate and real-time to measure the maximum sag of overhead lines within a span.Finally,highly reliable,highly accurate and large area promoted online monitoring system of Dynamic Capacity of transmission line is designed which solves the problems of existing online monitoring device.It achieves real-time forecasting,accurate calculation and monitoring.In view of the shortage of the existing transmission line Dynamic Capacity technology and the monitoring system,Thesis puts forward the model based on wire fixed temperature to the real-time calculation of the maximum transmission capacity.And designed the Dynamic Capacity-online Monitoring System,it greatly enhances the effect of Dynamic Capacity and the level of risk control;alleviates bottleneck of power transmission capacity.Each hardware unit of an online monitoring system is designed and it can achieve real-time,secure and reliable Dynamic Capacity of transmission lines.