Editing Power electronics (section)

=== Smart grid ===

A [[smart grid]] is a modernized [[electrical grid]] that uses [[information and communications technology]] to gather and act on information, such as information about the behaviors of suppliers and consumers, in an automated fashion to improve the efficiency, reliability, economics, and sustainability of the production and distribution of electricity.<ref>{{cite web | url =http://www.pnl.gov/main/publications/external/technical_reports/PNNL-17167.pdf | title = Pacific Northwest GridWise™ Testbed Demonstration Projects, Part I. Olympic Peninsula Project | access-date = 2014-01-15 | author = D. J. Hammerstrom|display-authors=etal}}</ref><ref>{{cite web | url = http://energy.gov/oe/technology-development/smart-grid | title = Smart Grid / Department of Energy | access-date = 2012-06-18 | author = U.S. Department of Energy}}</ref>

Electric power generated by [[wind turbine]]s and [[hydroelectric]] turbines by using [[induction generator]]s can cause variances in the frequency at which power is generated. Power electronic devices are utilized in these systems to convert the generated ac voltages into high-voltage direct current ([[HVDC]]). The HVDC power can be more easily converted into three phase power that is coherent with the power associated to the existing power grid. Through these devices, the power delivered by these systems is cleaner and has a higher associated power factor. Wind power systems optimum torque is obtained either through a gearbox or direct drive technologies that can reduce the size of the power electronics device.<ref name=Carrasco_Smart_Grid>{{cite journal|last=Carrasco|first=Juan Manuel|author2=Leopoldo Garcia Franquelo |author3=Jan T. Bialasiewecz |author4=Eduardo Galvan |author5=Ramon C. Portillo Guisado |author6=Ma. Angeles Martin Prats |author7=Jose Ignacio Leon |author8=Narciso Moreno-Alfonso |title=Power-Electronic Systems for the Grid Integration of Renewable Sources: A Survey|date=August 2006|volume=53|issue=4|page=1002|doi=10.1109/tie.2006.878356|citeseerx=10.1.1.116.5024|s2cid=12083425}}</ref>

Electric power can be generated through [[photovoltaic cell]]s by using power electronic devices. The produced power is usually then transformed by [[solar inverter]]s. Inverters are divided into three different types: central, module-integrated, and string. Central converters can be connected either in parallel or in series on the DC side of the system. For photovoltaic "farms", a single central converter is used for the entire system. Module-integrated converters are connected in series on either the DC or AC side. Normally several modules are used within a photovoltaic system, since the system requires these converters on both DC and AC terminals. A string converter is used in a system that utilizes photovoltaic cells that are facing different directions. It is used to convert the power generated to each string, or line, in which the photovoltaic cells are interacting.<ref name=Carrasco_Smart_Grid />

Power electronics can be used to help utilities adapt to the rapid increase in distributed residential/commercial [[solar power]] generation. Germany and parts of Hawaii, California, and New Jersey require costly studies to be conducted before approving new solar installations. Relatively small-scale ground- or pole-mounted devices create the potential for a distributed control infrastructure to monitor and manage the flow of power. Traditional electromechanical systems, such as [[capacitor bank]]s or [[voltage regulator]]s at [[Electrical substation|substations]], can take minutes to adjust voltage and can be distant from the solar installations where the problems originate. If voltage on a neighborhood circuit goes too high, it can endanger utility crews and cause damage to both utility and customer equipment. Further, a grid fault causes photovoltaic generators to shut down immediately, spiking the demand for grid power. Smart grid-based regulators are more controllable than far more numerous consumer devices.<ref name=tr1401>{{cite web|first=Martin |last=LaMonica |url=https://www.technologyreview.com/2014/01/21/174504/power-electronics-smooth-solar-transition/ |title=Power Electronics Could Help Grid and Solar Power Get Along &#124; MIT Technology Review |publisher=Technologyreview.com |date= 2014-01-21|access-date=2014-01-22}}</ref>

In another approach, a group of 16 western utilities called the Western Electric Industry Leaders called for the mandatory use of "smart inverters." These devices convert DC to household AC and can also help with power quality. Such devices could eliminate the need for expensive utility equipment upgrades at a much lower total cost.<ref name=tr1401 />