Optimal power dispatch in solar‐assisted uninterruptible power supply systems

Abstract

Summary Many countries in the developing world undergo regular power outages (scheduled and nonscheduled) due to lack of sufficient generation capability or transmission and distribution bottlenecks. Therefore, uninterruptible power supply (UPS) systems are commonly installed to critical power loads during daily power outages. While the integration of solar photovoltaic (PV) with these UPSs has seen rapid growth in recent years, their incorporation in conventional topologies is highly suboptimal. Therefore, in this work, we formulate a mathematical framework for optimal solar PV integration with domestic UPS systems for minimum cost solution incorporating all relevant system constraints and requisite system losses. We also propose and develop a retrofitting technological solution to integrate solar PV with typical UPS systems for optimal system operation. Results show that the proposed methodology and system implementation can achieve cost savings of up to 40.6% compared with conventional UPS system (without solar) in typical scenarios. In addition, with the proposed optimized utilization of PV, the grid utilization is decreased by 75% compared with the conventional case where UPS is integrated with solar using standard maximum power point charge controllers. This work is therefore highly useful for many developing regions with intermittent grids.

Stateflow-Based Energy Management Strategy for Hybrid Energy System to Mitigate Load Shedding

“…To represent the behavior of load shedding, the supply from the utility is plotted in the form of a unit step function [10]. Figure 8a shows the daily power supply schedule of a local distribution feeder of Quetta city for one summer day (14 June 2020) [40].…”

“…However, the system becomes more vulnerable if the grid is weak and subjected to load shedding-a condition whereby the utility disconnects the electricity supply to specific customers on a time-sharing basis. The load shedding is commonly used in countries or regions in which the supply of electricity is inadequate [10]. These scheduled disruptions can complicate the HES control because the system has to undergo frequent transitions between different operating modes to sustain the load demand.…”

“…Despite many studies for the grid-connected system [6,11], limited research has been done on load shedding. For instance, the optimal power dispatch in solar assisted uninterruptible power supply systems for residential application is investigated in [10,12]. Both research works, however, focused toward the feasibility of the designed system in terms of costs.…”

Towards Developing a Large Distributed Energy Storage Using a Weighted Batteries Scheduling Scheme

“…Now, the electricity shortfall is almost over and these batteries need to be utilized. One of our collaborator research group is working on instrumenting the UPSs for improved control [12][13][14]. Therefore, the proposed scheme is particularly useful in the context of Pakistan where a large number of consumers has already installed battery-based UPSs.…”

Failure detection‐less approach for wide sustained operation of MPPT based stand‐alone solar photovoltaic system during failure/disconnection of battery

“…In recent decades, solar photovoltaic (SPV) energy conversion systems have been considered as one of the most promising renewable sources of electrical energy throughout world . Research works on stand‐alone SPV system having battery storage are published in various articles . The stand‐alone system is used in diversified applications such as water pumping process, spacecraft, electric vehicle, and electrification in remote areas .…”