Study On Integration Of Transmission Line Heat Capacity And Wind Power Generation

Owing to the situation that the transmission capability of power system restricts the development of power generation and load,transmission lines play a pivotal role in the construction of power grid as the carrier for power transmission.Taking temperature as the essential factor which limits the transmission line heat capacity,dynamic thermal rating(DTR)realize transmission line maximum allowable current under the maximum allowable temperature based on the actual meteorological environment and thermal inertia of temperature.As a result of non-polluting and renewable energy wind power generation is increasingly being incorporated into the grid.And commissioning a study on transmission line heat capacity and wind power generation integratedly as well as making use of DTR more effectively to improve transmission line heat capacity and wind power accommodation capacity has become a subject that need to be researched urgently in such a situation that the wind power output as well as the transmission line heat capacity is affected by the meteorological parameters,especially the wind speed.Furthermore,because of describing the individual thermal rating of conductors and breaking away from the operation scheduling it's of great significance to combine DTR with operation scheduling and control for improving the security and stability of power system.First,based on the DTR assessment model under IEEE standard,the heat gain and loss of transmission lines are analyzed and the expanded factor estimation model including evaporation heat loss of DTR is established with the analysis of the effects caused by evaporation and melting of rain and snow on the conductor surface.Then,the difference of transmission line heat capacity and the relationship among heat loss of conductor under the IEEE standard model and the expanded factor model are analyzed in the form of case study,as well as the influence of evaporation heat loss on heat balance state of conductor and improving the utilization ratio of transmission lines.Next,combing the power characteristic curve of wind turbine and current characteristic curve of transmission line under different wind speed and angle with the type of "one turbine one substation" for current collection lines of wind farm,the principle of current capacity improvement of wind farm outgoing transmission line is analyzed.And the effects of DTR for improving the number of wind turbines put into operation as well as the capacity of wind power utilization are discussed in the form of case study.Analyzing the factors which affect short-time overload capacity of transmission lines,the influence of DTR on relieving congestion of power system,reducing load cutting and declining wind cutting ratio is analyzed in the form of case study.Final,taking conductor temperature,permitting time for temperature rise and the power flow into consideration together,the advanced application of DTR is realized from the view of operation scheduling and control.Then the effects and advantages of advanced thermal rating on the treatment of contingency in power grid are analyzed in the form of case study.Additionally,the influence of wind power variation on advanced scheduling decision making is analyzed with wind power forecasting.In conclusion,it's significant and meaningful to research transmission line heat capacity and wind power generation integratedly and combine with operation scheduling of power system for improving wind power accommodation capacity and ensuring safe and stable operation of power grid.