HP ML370 Power basics for IT professionals - Page 5

Regional power distribution, Power distribution at the site

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minimize transmission losses. Three-phase alternating current from the generating station is increased to the required transmission voltage by step-up transformers; it is stepped back down once it reaches the load center for local distribution. Regional power distribution Distribution voltages range from 2.4kV to 34.5kV in North America; the most common voltages are 2400V, 4160V, 7200V, 12470V, 24kV and 34.5kV. Distribution voltages range from 3.3kV to 33kV in Europe and Asia; but the most common voltages are 3300V, 6600V, 10kV, 11kV, 20kV and 33kV. Pole lines are used to distribute power at distribution voltages to light industrial, commercial, and residential facilities. As a general rule, light industrial and commercial facilities are serviced at a distribution voltage and use local substations to step down the voltage to the most common voltage (480VAC) for commercial facilities. Power distribution at the site Electricity travels from the generating station to the place where it will be used through the transmission system. Then it is guided from the building's internal wiring to devices by means of power outlets, power plugs and sockets1, and power distribution units (PDUs). Efficient planning of power channels within a data center, especially for use with servers, can help maximize power flow through the infrastructure and minimize costs and heat generation. Most large commercial buildings in North America receive 480V/277VAC, three-phase power. The 480/277VAC is connected in one of three ways: to a switchgear line-up, to a 480V motor control center, or to a 480VAC power panel. Each has feeder breakers serving all loads inside the building. A distribution panel divides the loads across the proper circuits and outlets in the building and can provide single-phase, two-phase, or three-phase power output. A gasoline or diesel-powered backup or emergency generator can be supplied to provide electrical power in the event of a power outage. Figures 4 through 7 depict the standard North American distribution method using Institute of Electrical and Electronics Engineers (IEEE) Standards for serving single-phase and three-phase power using a backup generator with either an automatic transfer switch (ATS) or a UPS. Incoming power is normally supplied by the utility. In the event of a utility failure, an ATS switches between sources so that power is delivered by the backup generator. Connecting the server room power panel to the ATS ensures that power will be available to the servers even when the utility fails. 1 The terms plug and socket are being used consistently in this document to refer to power plugs and power sockets. The glossary at the end of this document identifies many synonyms for these terms. 5

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minimize transmission losses. Three-phase alternating current from the generating station is increased
to the required transmission voltage by step-up transformers; it is stepped back down once it reaches
the load center for local distribution.
Regional power distribution
Distribution voltages range from 2.4kV to 34.5kV in North America; the most common voltages are
2400V, 4160V, 7200V, 12470V, 24kV and 34.5kV. Distribution voltages range from 3.3kV to
33kV in Europe and Asia; but the most common voltages are 3300V, 6600V, 10kV, 11kV, 20kV
and 33kV. Pole lines are used to distribute power at distribution voltages to light industrial,
commercial, and residential facilities. As a general rule, light industrial and commercial facilities are
serviced at a distribution voltage and use local substations to step down the voltage to the most
common voltage (480VAC) for commercial facilities.
Power distribution at the site
Electricity travels from the generating station to the place where it will be used through the
transmission system. Then it is guided from the building’s internal wiring to devices by means of
power outlets, power plugs and sockets
1
, and power distribution units (PDUs). Efficient planning of
power channels within a data center, especially for use with servers, can help maximize power flow
through the infrastructure and minimize costs and heat generation.
Most large commercial buildings in North America receive 480V/277VAC, three-phase power. The
480/277VAC is connected in one of three ways:
to a switchgear line-up, to a 480V motor control
center, or to a 480VAC power panel.
Each has feeder breakers serving all loads inside the building.
A distribution panel divides the loads across the proper circuits and outlets in the building and can
provide single-phase, two-phase, or three-phase power output. A gasoline or diesel-powered backup
or emergency generator can be supplied to provide electrical power in the event of a power outage.
Figures 4 through 7 depict the standard North American distribution method using Institute of
Electrical and Electronics Engineers (IEEE) Standards for serving single-phase and three-phase power
using a backup generator with either an automatic transfer switch (ATS) or a UPS.
Incoming power is normally supplied by the utility. In the event of a utility failure, an ATS switches
between sources so that power is delivered by the backup generator. Connecting the server room
power panel to the ATS ensures that power will be available to the servers even when the utility fails.
1
The terms
plug
and
socket
are being used consistently in this document to refer to power plugs and power
sockets. The glossary at the end of this document identifies many synonyms for these terms.
5