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Weather has a significant impact on the generation, transmission, and demand of electricity. The effect of weather changes is seen through the fluctuation of electricity demand. Electricity demand is influenced by temperature, wind speed, humidity, precipitation, and cloud cover. These further effects practically demand for air conditioning, space heating, refrigeration and water pumping loads. Transmission systems are found to be sensitive through thermal constraints and faults caused by extreme weather conditions. In electrical systems, one of the main factors that limit the transport of energy is the temperature of the conductor. Knowing the transmission system, and the critical sections both geographical and climatic, the temperature of the line as well as the transient and dynamic thermal rating can be calculated. Demand levels are also weather sensitive.
Thus, all these pose serious challenges to electricity transmission and supply industry. It is also true that the forecasted load by load forecasters at load dispatch center, depends on the reliability of line that weather it is conveying that much of MW share to all related areas. The transmission system should be protected from weather effects. So proper means like some type of devices should be equipped over the tower which should sense the weather factors like temperature, wind, humidity, etc in prior.
Wind is defined as air in motion and is expressed in terms of direction and speed. Wind direction is regarded as the direction from which it blows and speed as the rate of movement of air in its instantaneous direction. Most ampacity calculations assume that wind speed has no correlation with other weather variables. This assumption has led to a significant understatement in ampacity assumptions for capabilities during high daytime temperatures.
The diurnal pattern varies, depending on the surrounding geography. But generally, the wind speed is significantly higher during the day than during the night. The wind is not only unpredictable, it is highly variable. It varies with space and with time. The lower the wind speed, the higher the relative turbulence i.e. higher the temperature, the higher the turbulence. A large amount of the turbulence of wind is generated by temperature differences. These are more pronounced during the daytime and when the temperatures are high. However, the transmission capacity of an overhead line increases when wind speed is high, due to the cooling caused by wind in the distribution lines. Dynamic line rating (DLR) systems allow monitoring real weather conditions and calculating the real capacity of lines.
In the spatial dimension, the wind speed variation along the overhead transmission line makes the conductor temperature and line parameter show a non-uniform distribution characteristic, which has an important influence on the system’s operating status. In India, the Bureau of Indian Standards (BIS) is used as IS:802 (Part-3) and IS:5613(Part-3/Section -1 & Section- 2) for various design parameters.
