Optimal operation and management of energy systems under extreme temperature conditions

Includes bibliographical references.2019 Summer.Natural disasters can lead to temporary or permanent damages to the power system. Possible damages to the electric power grid can lead to large-scale interruption in electric service, which could greatly impede post-disaster relief efforts. To make communities resilient against natural hazards, the power grid must be able to mitigate the impact of such disasters and to provide post-disaster self-healing capability. In this framework, the network operator has to think ahead about the mitigation techniques that can be incorporated into the network optimal power flow in order to reduce the adverse consequences as much as possible. Since every natural disaster behaves differently, care must be taken based on the nature of each phenomenon. However, there are some natural disasters that have commonalities and can be classified in the same group. High-temperature-related natural disasters are one such example. These events expose the network to high temperature rises which can easily jeopardize the reliability of the system. Wildfires and heat waves are the most well-known instances of these hazards. Wildfires are natural or manmade events that occur in forested and grassland regions. From among various power system assets, overhead transmission lines are in particular vulnerable to wildfire, since they often pass through such areas. The heat generated by the fire can increase the surface temperature of the overhead conductors in its vicinity. Even moderate temperature rises can lead to increased conductor sag and subsequent chances of flashover, whereas in extreme cases, conductor annealing and permanent loss of tensile strength can be expected. One way to avoid this, is to dynamically adjust the thermal rating of the at-risk lines, so that reduced loading of the line counteract the heat gained from the fire. However, this can affect the flow of power and dispatch of the generation units. Similar effects on the grid can be expected during heat waves, which are prolonged periods of excessive ambient temperature that may last up to several weeks. In addition to posing health threats to the society, these events may easily push the power grid towards its operational limits. The maximum capacity of many energy resources gets negatively affected by excess temperatures. This can be in addition to the expected loss of life due to operation under harsh conditions. Overhead lines, again, experience excessive conductor surface temperatures that can drastically reduce their power transmission capacity. To make matters worse, the reduction in generation and/or transmission capacity will coincide with a rise in electric demand, often attributed to overutilization of air-conditioning systems. This can jeopardize the ability of the power grid to maintain system stability. A key to ensure that the grid continues operating safely and securely is to incorporate the effect of temperature into its operation schedule. Another way to mitigate the effect of high temperature rises is through using demand response potential at the end user’s level, such as industrial and residential loads. Industrial loads consume a major portion of the overall demand and can form an industrial microgrid which is equipped with on-site generation. From a mathematical standpoint, the optimal operation of such network is an interesting and challenging problem due to the presence of various and at times conflicting objective functions. Operators of industrial plants look into minimizing cost, reducing carbon emissions, optimizing asset utilization, and maximizing profits. These considerations make the operation of an industrial microgrid a multi-objective optimization problem that not only seeks the optimal operation of the plant but can also introduce significant advantages such as demand responsive behavior. These large demand responsive loads can be significantly beneficial in the operational framework of the system during high temperature-related natural disasters. Moreover, since over-utilization of air-conditioning (A/C) systems is one of the biggest issues during high temperature rises, optimally allocating energy and demand responsive resources in a power distribution system exposed to a heat wave can be beneficial in order to maintain the load-generation balance and minimizing the operational costs. For this purpose, the temperature set-points can be regulated for each individual demand responsive A/C units in order to help the distribution network operator to manage the network as efficient as possible. However, due to the stochastic behavior of building occupants, the proposed methodology could be totally an inferior solution. Thus, a robust multi-objective optimization framework is needed to consider all uncertainties and avoid health risks to the residents (especially children and the elderly) with an acceptable level of conservatism