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Standby Power Systems
Published in Michael F. Hordeski, Emergency and Backup Power Sources:, 2020
UPS systems can be grouped into offline, online, and hybrid. The newer types act as an intelligent power supply. A standby or offline UPS operates by switching from commercial power to battery power when the commercial power drops below a certain voltage level. The inverter is not powered, except during power outages. Since the load receives power directly from the utility line as long as it is available, the load remains exposed to power disturbances such as spikes, noise, surges, and brownouts. Because of this, these systems should be used with a line conditioner or voltage regulator. Another disadvantage is the time it takes for the unit to switch over after it senses that the voltage has dropped. Some sensitive equipment may not be able to ride through this transition period without being affected. A switching time of four milliseconds or less is needed for electronic loads such as computer or control hardware. The major advantage of an offline UPS is its low cost.
Provide backup power
Published in Michael Wiklund, Kimmy Ansems, Rachel Aronchick, Cory Costantino, Alix Dorfman, Brenda van Geel, Jonathan Kendler, Valerie Ng, Ruben Post, Jon Tilliss, Designing for Safe Use, 2019
Michael Wiklund, Kimmy Ansems, Rachel Aronchick, Cory Costantino, Alix Dorfman, Brenda van Geel, Jonathan Kendler, Valerie Ng, Ruben Post, Jon Tilliss
At well-equipped hospitals, a loss of electrical power from the external grid triggers a backup power generator that restores power quickly and might provide power for several days. In such cases, critical equipment (e.g., anesthesia machines, ventilators) used in operating rooms and intensive care units will continue working as usual. Sensibly, a product used in critical medical procedures will incorporate an uninterruptable power supply (UPS)—a battery or group of batteries with sufficient capacity to power the equipment as long as might be required. A UPS can take over electrical supply duties in a matter of milliseconds after its internal circuit detects a loss of voltage from the main power source.1 The UPS covers for the time it might take for a generator to start up and for longer periods in the event that it does not.
Garment-on-Hanger Order-Fulfillment Operations
Published in David E. Mulcahy, John P. Dieltz, Order-Fulfillment and Across-the-Dock Concepts, Design, and Operations Handbook, 2003
David E. Mulcahy, John P. Dieltz
An uninterruptible power supply (UPS) provides sufficient electric power to prevent a computer crash during a power outage, and permits the facility to operate pick-line electrical equipment for a short period of time. This time period is dependent on the UPS specifications. A UPS can also help avoid damage to equipment caused by power spikes during electrical storms. Other UPS considerations include the types of systems that are connected to specific electrical equipment, the period of time to operate on battery power, and the availability and capacity of a standby generator. Most UPS systems are designed to protect computer and other sensitive electronic components. They automatically pick up the load when the primary electrical source is interrupted.
Analytical comparison and implementation of different inverter topologies for three-phase on-line uninterruptible power supply
Published in International Journal of Ambient Energy, 2022
The uninterruptible power supply is provided between a primary power source and the input of the equipment to be protected, to eliminate the effects of a temporary power failure and power quality (Deng, Oruganti, and Srinivasan 2008). In the UPS, the battery is used to maintain the continuous power during the power outage. In addition to providing regulated power to the load, the UPS system also protects equipments from the surges and overload conditions. The three general categories of modern UPS systems are off-line (standby) UPS, line interactive UPS and on-line UPS (Bekiarov and Emadi 2002). In this research work, the on-line UPS is considered because the load is protected from faults present in the power grid such that the voltage and frequency of the AC can be adjusted in the UPS and during a power failure, there is no transition time to power the load from battery.
Time history analysis for investigation of dynamic behavioral characteristics of uninterruptible power supply system
Published in Journal of Structural Integrity and Maintenance, 2022
Seung-Jae Lee, Ji-Eon Lee, Ngoc Hieu Dinh, Kyoung-Kyu Choi
The test specimen investigated in this study is a 100-kV UPS; its details are summarized and shown in Table 1 and Figure 1, respectively. The UPS is a device that normally supplies power for a certain time period when power is suddenly interrupted. The specimen is a cabinet-type UPS compliant with IEC-60950-1 (IEC 60950–1, 2018). It has a total weight of 0.8 t and overall dimensions of 750 mm (width) × 800 mm (length) × 1800 mm (height). As depicted in Figure 1, the UPS is composed of two primary parts: a 300-kg cooling plate and a 460-kg transformer. In addition, according to the manufacturer, because the transformer, which is heavier than the cooling plate, is located at the bottom, the center of mass of the UPS is located at one-third the height of the device measured from the base in the vertical direction and centered on the plane. Moreover, its internal parts, such as semiconductors, are sensitive to vibration. Consequently, if excessive displacement occurs, then the device may malfunction due to cabinet deformation and collision of internal parts.
Design and Simulation of Hybrid DG System Fed Single-Phase Dynamic Voltage Restorer for Smart Grid Application
Published in Smart Science, 2020
Table 1 gives the insight into the effect of voltage sags, swells, and interruptions on household loads along with the importance of need of voltage sag mitigation and the way it affects office as well as home appliances [26–28]. Practically, the economic impacts of interruptions on domestic consumers are rather higher. An uninterruptible power supply (UPS) system is an electrical device that is generally used to provide emergency power support to a load in case of interruptions from the source side. That is why proposed DVR model has been enabled with the special feature of working as UPS in case of interruptions. Thus, the special feature of functioning as an uninterruptible power source (UPS) makes the proposed DVR model a unique solution for both voltage and power disturbances in supply side. In this work, DVR system has been designed for single-phase load application. With the proposed DVR model voltage sag can be mitigated and undesirable losses of time and money can be avoided.