On the Efficiency in Electrical Networks with AC and DC Operation Technologies: A Comparative Study at the Distribution Stage

Abstract

This research deals with the efficiency comparison between AC and DC distribution networks that can provide electricity to rural and urban areas from the point of view of grid energy losses and greenhouse gas emissions impact. Configurations for medium- and low-voltage networks are analyzed via optimal power flow analysis by adding voltage regulation and devices capabilities sources in the mathematical formulation. Renewable energy resources such as wind and photovoltaic are considered using typical daily generation curves. Batteries are formulated with a linear representation taking into account operative bounds suggested by manufacturers. Numerical results in two electrical networks with 0.24 kV and 12.66 kV (with radial and meshed configurations) are performed with constant power loads at all the nodes. These simulations confirm that power distribution with DC technology is more efficient regarding energy losses, voltage profiles and greenhouse emissions than its AC counterpart. All the numerical results are tested in the General Algebraic Modeling System widely known as GAMS.

Exact minimization of the energy losses and the CO2 emissions in isolated DC distribution networks using PV sources

“…Regarding the greenhouse gas emissions, the information about diesel generators presented in [39]. Here, the most relevant gas emissions for medium size diesel generators (those with capabilities lower than 10 MW) is the carbon dioxide, i.e., CO2, with an average emissions rate of 612.35 kg/MWh.…”

AC vs DC Distribution Efficiency: Are we on the Right Path?

“…Although wind can be better optimized with DC systems, there is a negligible trend of considering wind plants as rooftop generators for the case of residences. However, it is important to point out the studies that take wind into account for example [77][78].…”

Optimal Integration of Photovoltaic Sources in Distribution Networks for Daily Energy Losses Minimization Using the Vortex Search Algorithm

“…In general, electric power transmission and distribution networks differ in the voltage levels at which they operate, which implies transmission voltages greater than 220 kV, between 57 and 220 kV for sub-transmission, and less than 57 kV for distribution [2]. However, the predominant voltage energy distribution level in Colombia ranges between 11.4 and 13.8 kV, respectively [3]. These electric networks present differences in their characteristics since the transmission usually uses meshed systems, and the distribution uses radial characteristics [4,5].…”

“…Due to these differences in electrical energy losses, the transmission levels are between 1.5% and 2% of the energy generated in peak hours, while the energy distribution can vary between 6% and 18%. The above-mentioned implies that, in the worst case, 18% of the distribution level energy is transformed into heat in the resistance lines and transformers in the distribution mainly [3,6]. Given the high levels of losses in the energy distribution, it is necessary to quantify them to determine an optimal solution to this problem [7].…”