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Evolving Power System Technologies and Considerations
Published in Dale R. Patrick, Stephen W. Fardo, Brian W. Fardo, Electrical Power Systems Technology, 2021
Dale R. Patrick, Stephen W. Fardo, Brian W. Fardo
The design and operation of electrical power distribution systems has become a very important science. Well-engineered power systems of today are connected together in such a way that if a problem occurs in one system, it can be supplemented by another system. Electrical loads can be transferred easily from one system to another. The United States has a very reliable “grid” system which maintains electrical power to customers at the proper voltage level without interruption. It is extremely rare for “black-outs” or “brownouts” to occur. These conditions are avoided by proper planning for situations of extremely high demand. A blackout is a complete interruption of electrical power, while a brownout is a reduction of voltage level to the consumer. A brownout could be purposely done in order to deliver available power at a reduced voltage to avoid a blackout during a problem of extremely high demand. High demand usually occurs during abnormally hot or cold temperatures over an extended period of time.
PV Power Generation
Published in Anco S. Blazev, Photovoltaics for Commercial and Utilities Power Generation, 2020
Other power quality problems may also be considered reliability problems because they occur when the transmission system is not capable of meeting the load on the system, such as: Brownouts are a persistent lowering of system voltage caused by too many electric loads on the transmission line.Blackouts are, of course, a complete loss of power. Unanticipated blackouts are caused by equipment failures, such as downed power lines, blown transformers, or a failed relay circuits.“Rolling” blackouts are intentionally imposed upon a transmission grid when the loads exceed the generation capabilities. By blacking out a small sector of the grid for a short time, some of the load on the grid is removed, allowing the grid to continue serving the rest of the customers. To spread the burden among customers, the sector that is blacked out is changed every 15 minutes or so—and hence, the blackouts “roll” through the grid’s service area.
Planning a Carton or Full-Case Order-Fulfillment Operation
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
Also required is an uninterruptible power supply (UPS), which during a brownout or electrical power failure provides sufficient electric power to prevent a computer crash and to permit the facility to operate all pick-line electrical equipment for a predetermined time period. This time period is a shift portion or the entire shift. The other UPS considerations include the source of electricity — battery power, which is connected to specific electrical equipment and is designed to operate for a short time period, or a diesel-powered generator that is designed with the capacity to provide the entire pick line or all of a facility's electrical equipment for a long time period — and the method used to activate the UPS (a manual start-up or online start-up). Since most UPS systems are designed to protect a microcomputer or host computer, most UPS systems are started by an online method.
Quantifying the seismic risk for electric power distribution systems
Published in Structure and Infrastructure Engineering, 2021
Yang Liu, Liam Wotherspoon, Nirmal-Kumar C. Nair, Daniel Blake
Panteli et al. (2017) considered temporal impacts of extreme weather events on a national transmission grid, where sequential MCS was applied to simulate the system functionality over time. Resilience metrics factoring in both functional and structural aspects were proposed to better characterise performance degradation due to increasing intensities of the extreme weather event. Despite the literature on individual component and transmission network performance, the performance of distribution networks following extreme hazard events have rarely been considered in their entirety. Winkler, Duenas-Osorio, Stein, and Subramanian (2010) developed a framework to assess the performance of power transmission and distribution system under hurricane events. The framework embeds component fragility functions and connectivity based network study to capture the impact of component and network topology on system reliability. However, a graph model based on node connectivity can significantly underestimate power loss, as connected consumers can still experience power outage or brownout due to voltage drop. Han et al. (2009) present a statistical power outage risk estimation model, where principle component analysis is used to deal with collinearity and generalised linear models are employed for regression analysis. However, this statistical approach does not consider any internal mechanisms of the distribution system.