Power grid in the context of "Complex system"

In electrical engineering, a transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer's core, which induces a varying electromotive force (EMF) across any other coils wound around the same core. Electrical energy can be transferred between separate coils without a metallic (conductive) connection between the two circuits. Faraday's law of induction, discovered in 1831, describes the induced voltage effect in any coil due to a changing magnetic flux encircled by the coil.

Transformers are used to change AC voltage levels, such transformers being termed step-up or step-down type to increase or decrease voltage level, respectively. Transformers can also be used to provide galvanic isolation between circuits as well as to couple stages of signal-processing circuits. Since the invention of the first constant-potential transformer in 1885, transformers have become essential for the transmission, distribution, and utilization of alternating current electric power. A wide range of transformer designs is encountered in electronic and electric power applications. Transformers range in size from RF transformers less than a cubic centimeter in volume, to units weighing hundreds of tons used to interconnect the power grid.

On December 23, 2015, the power grid in two western oblasts of Ukraine was hacked, which resulted in power outages for roughly 230,000 consumers in Ukraine for 1-6 hours. The attack took place during the ongoing Russo-Ukrainian War (2014-present) and is attributed to a Russian advanced persistent threat group known as "Sandworm". It is the first publicly acknowledged successful cyberattack on a power grid.

A charging station, also known as a charge point, chargepoint, or electric vehicle supply equipment (EVSE), is a power supply device that supplies electrical power for recharging the on-board battery packs of plug-in electric vehicles (including battery electric vehicles, electric trucks, electric buses, neighborhood electric vehicles, and plug-in hybrid vehicles).

There are two main types of EV chargers: alternating current (AC) charging stations and direct current (DC) charging stations. Electric vehicle batteries can only be charged by direct current electricity, while most mains electricity is delivered from the power grid as alternating current. For this reason, most electric vehicles have a built-in AC-to-DC converter commonly known as the "on-board charger" (OBC). At an AC charging station, AC power from the grid is supplied to this onboard charger, which converts it into DC power to recharge the battery. DC chargers provide higher-power charging (which requires much larger AC-to-DC converters) by building the converter into the charging station to avoid size, weight and cost restrictions inside vehicles. The station then directly supplies DC power to the vehicle, bypassing the onboard converter. Most modern electric vehicles can accept both AC and DC power.