Research on Transmission Line Loss and Carrying Current Based on Temperature Power Flow Model

Abstract

Abstract. In conventional power flow calculation, the lines resistances are always assumed to be invariable, which does not conform to the actual. Resistances of transmission lines are changed with changes of external environment and power distribution. In this paper, a model of power flow calculation considering temperature is presented. Temperatures and resistances of branches are linked with the modified power flow equations in this model. At the same time, the maximum current-carrying capacity is also analyzed and temperature can be gained by the algorithm to detect current. Through two kinds of power flow algorithm are compared and analyzed, the results show temperature of conductor has a very significant impact on the power flow calculation which should be paid attention to.

Modeling and Simulation of Coupled Power Transmission Line: A Systematic Approach

“…Increment in temperature and current is supported by the coupled terms in Eqs. (7,9), respectively, which implies that the coupling terms were well posed in the coupled model, hence, these models simulated the field potentials effectively. Furthermore, the positive linear behavior of temperature and current is supported by physical laws of Fourier's and Ohmic laws.…”

Determining the causes of electricity losses and the role of management in curbing them: A case study of City of Tshwane Metropolitan Municipality, South Africa

“…According to Luo et al (2015), distribution line losses can also occur due to conductor losses, which are triggered by absorbed and emitted heat. They further say that a heat balance question should be considered to calculate the relationship between heat and conductor resistance.…”

Can storage reduce electricity consumption? A general equation for the grid-wide efficiency impact of using cooling thermal energy storage for load shifting

“…Power plant efficiency improves as ambient temperature and relative humidity decrease [6,7]. T&D network efficiency improves with decreasing ambient temperature and line current, among other factors [8,9]. Air conditioning equipment efficiency improves significantly with lower ambient temperatures [35,36].…”

“…T&D losses increase with electrical current and line resistance, where electrical current increases with system electricity demand and line resistance increases with the temperature of the line's electrical conductor material. Conductor temperature depends on electrical current, ambient temperature, wind speed, solar radiation, and other factors contributing to the heat balance equations shown in equation (4) [8,9].…”

“…Yet, though an individual storage technology increases energy consumption at its connection point to the grid, its load shifting effects can improve the efficiency of the grid as a whole. For example, the efficiency of the generator fleet and the transmission and distribution (T&D) network increases as ambient temperature, relative humidity, and line current decrease [6][7][8][9]. Generally, in cooling-dominated climates, peak demand and high ambient temperature occur during the daytime (when power plants, air conditioners, and the T&D network are less efficient), while low demand and low ambient temperatures occur at night.…”