= Electric power system
{wiki}
An <electric power system> is an interconnected arrangement that produces, transfers, controls, and consumes electrical <energy>. <Electricity generation> supplies electrical <power>, <electric power transmission> carries it between regions, and <electric power distribution> delivers it to <electrical loads>. <Electrical generators>, <electrical transformers>, and <transmission lines> perform different parts of this task. The one-line apparatus diagram in the DOE handbook makes these connections concrete: it follows supplies through switching and protection equipment to consuming circuits.<DOE Fundamentals Handbook Electrical Science>[Volume 4, Module 15, System Components and Protection Devices, printed pp. 1–6, Figure 1]{ref}
A useful calculation separates delivered <power> from conductor heating. Consider an idealized two-conductor <direct current> link delivering $P=10\,\mathrm{MW}$ at load <electric potential difference> $V=10\,\mathrm{kV}$, with total outgoing-plus-return <electrical resistance> $R=0.1\,\Omega$. Its <electric current> and resistive loss are
$$
I=\frac{P}{V}=1000\,\mathrm A,\qquad P_{\rm loss}=I^2R=100\,\mathrm{kW}.
$$
Delivering the same <power> at $100\,\mathrm{kV}$ reduces the <electric current> to $100\,\mathrm A$ and the loss to $1\,\mathrm{kW}$. This is a fixed-load, fixed-resistance comparison; it omits converter loss, insulation constraints, and changes in conductor temperature. In an <alternating current> network, an <electrical transformer> changes the operating <electric potential difference> without itself generating the delivered <energy>.<DOE Fundamentals Handbook Electrical Science>[Volume 4, Module 13, Transformer Theory, printed pp. 11–13, copper loss and efficiency]{ref}
At each instant, generation, imports, and storage discharge must supply <electrical load>, exports, losses, and storage charging. A sudden imbalance can initially draw on stored <energy>; it cannot persist indefinitely without changing the operating state. This <electric power balance during a demand step> connects network calculations to control and to the smaller, deliberately bounded <microgrid>.
Back to article page
