## 2 Literature Review
### Temperature Effect  
The short-term electrical load variation can be related to factors like the environment, population, or economy. Studies indicated a direct relation of load with temperature [7; 11; 12]. A study performed in France showed that the temperature has a negative correlation of 0.94 with the load [22], whereas a study performed in Bangkok's metropolitan area found that the electricity demand for residential load tended to increase by 6.79% for a 1 \({}^{\circ}\)C rise in temperature [24]. These two studies indicate a very different type of relationship for different locations based on a topological effect. Establishing a relation can be a challenging task. In the case of France, the country lies in a region with mild temperatures, such that the temperature varies from \(-5\) to \(25\)\({}^{\circ}\)C, whereas Bangkok lies in the equatorial region, and the temperature varies from 25 \({}^{\circ}\)C in the winter to 31 \({}^{\circ}\)C in the summer. Both have different temperature ranges, where one has cold temperatures and the other country has warm temperatures throughout the year, and electricity demand in both regions increases with an increase or decrease in temperature. The effect of the temperature may change from country to country, based on their topology and geographical location such that the effect can be positive, negative, or both in some cases. In Bangladesh, the temperature effect is fitted using a linear relation with the load [25]. Research shows that the linear slope of the electric load and temperature is higher during the summer rather than the winter season, as the rate of load increment is 53.14 MW/\({}^{\circ}\)C during the summer and 2.14 MW/\({}^{\circ}\)C during the winter. One study conducted on the electricity demand of China explored the relation by dividing the sample into two groups, south and north, which explained the effect of the temperature in different topologies. The results showed that the load increased by 0.002% for every one-degree decrease in temperature for the southern region, whereas the load in the north region tended to use 0.021% more electricity than the southern region with every one-degree increase in temperature [26]. For the load dataset of Thailand, the variation was discussed in terms of hours. The load varied from 50 MW/\({}^{\circ}\)C during the morning and evening hours, and the impact of the temperature was much higher during nighttime hours, where the results showed an increment of 100-200 MW/\({}^{\circ}\)C [7]. A similar case study conducted on Hokkaido showed that the rise in temperature from 25 to 26 \({}^{\circ}\)C increased the demand by 7% during daytime hours, whereas there was only a 2% increase during nighttime hours [27].  
However, depending on the type of consumers, the relation with the temperature can be different. A study performed on European load indicated that the demands for commercial and industrial loads were not affected much by the variation in temperature [11] such that the commercial and industrial loads had somewhat constant demand when considering the temperature. In the case of Hong Kong, the temperature tended to have a higher effect on the residential load in comparison with the commercial and industrial loads [12]. The analysis on the electrical load showed a 9.2% increment with the temperature for the residential sector, whereas the load only increased by 2.2% and 3% in the commercial and industrial sectors, respectively. These findings can be related to a load study done for Pune, India. The data showed that the industrial activities were not affected much by temperature variations, whereas residential activities showed an increment in the load of 1.5-2%/\({}^{\circ}\)C change in temperature [28].