Power Systems Last edited: Monday, June 1 st, 2015

Before Power Distribution Technology developed years before power distribution to the public: Batteries Arc Lights Incandescent Lights Electric Motors (vacuum pump)

DC vs. AC Direct current (DC) – DC machines – Batteries – Fuel cells – Photovoltaic Alternating current (AC) – AC machines – Power electronic converters – 60 Hertz in the US

Brush Electric Company HVDC distribution that transmitted over longer distances to one customer Niagara Falls to Buffalo Simple distribution system that could only power arc lights

Edison Electric Company Low voltage direct current system Better lightbulb Safer Short range use Powered Small DC motors Features added Electric meter Distribution System

Westinghouse Electric Company Low and High Voltage Alternating Current system Long distance transmission Able to change voltage Compatible with Edison Bulb Developed Westinghouse Bulb Own patent for AC Motor

Grid Expansion Grid distribution networks expanded until around The smaller grids slowly integrated into one system by connecting the distribution grids by transmission lines. More transmission lines were added during the 1930s as part of the Depression projects and rural areas received electricity By the 1960’s the gird was largely intact and upgrades occurred to make the lines more reliable.

Major Power Grid Components Generation Transmission –115 kVolts 765 kVolts –Networked Distribution –4 kVolts to 69 kVolts –Radial Load

Major Power Grid Components  All power systems have three major components: Generation, Transmission/Distribution, and Load.  Generation: Creates electric power.  Transmission/Distribution: Transmits electric power from generation to load.  Load: Consumes electric power.

Power in = Power Out

The Electric Grid Model

Interconnections

AC Transmission Grid

DC Transmission Components

Transmission & Distribution TransmissionDistribution networked connectionsradial connections power can be supplied from multiple sources power moves in one direction only typically higher voltages, above 100 kV typically lower voltages, below 100 kV mostly overhead, with some underground in urban areas most new construction is underground, especially in suburban and urban locations often source of large-scale blackouts the source of most blackouts, but these are local

Synchronism 16 Since most generation is from synchronous machines, the interconnected power system swings together.

North American Control Areas