Transcript IEC Voltage Standard and Recommendation

ELECTRICAL INSTALLATION
DESIGN
DET 207
Chapter 1: Introduction Electrical
Installation Design
• Define the IEC voltage standard and recommendations
• Define and explain TNB supply schemes
• Define and explain types of supply application
IEC Voltage Standard and Recommendation
The International Electrotechnical Commission (IEC) is a not-for-profit,
non-governmental international standards organization that prepares and
publishes International Standards for all electrical, electronic and related
technologies.
IEC standards cover a vast range of technologies from power generation,
transmission and distribution to home appliances and office equipment,
semiconductors, fibre optics, batteries, solar energy, nanotechnology and
marine energy.
Today, the IEC is the world's leading international organization in its field,
and its standards are adopted as national standards by its members.
IEC standards have numbers in the range 60000–79999 and their titles take a
form such as IEC 60038 : Voltage standard. The numbers of older IEC
standards were converted in 1997 by adding 60000, for example IEC 27
became IEC 60027.
IEC Voltage Standard and Recommendation
International Standard IEC 60038 defines a set of standard voltages for use
in low voltage and high voltage AC electricity supply systems.
IEC Voltage Standard and Recommendation
Definition of High Voltage :
The numerical definition of high voltage depends on the context
of the discussion. Two factors considered in the classification of
a "high voltage" are the possibility of causing a spark in air, and
the danger of electric shock by contact or proximity. The
definitions may refer either to the voltage between two
conductors of a system, or between any conductor and ground.
In electric power transmission engineering,
high voltage is usually considered any
voltage over approximately 35,000 volts. This
is a classification based on the design of
apparatus and insulation.
IEC Voltage Standard and Recommendation
Definition of High Voltage :
In the United State 2005 National Electrical Code (NEC), high
voltage is any voltage over 600 V .British Standard BS
7671:2008 defines high voltage as any voltage difference
between conductors that is higher than 1000 V AC or 1500 V
ripple-free DC, or any voltage difference between a conductor
and Earth that is higher than 600 V AC or 900 V ripple-free
DC.
The International Electrotechnical Commission
defines high voltage circuits as those with
more than 1000 V for alternating current and at
least 1500 V for direct current.
IEC Voltage Standard and Recommendation
Definition of Low Voltage :
Low voltage is an electrical engineering term that broadly identifies safety
considerations of an electricity supply system based on the voltage used.
"Low voltage" is characterised by carrying a substantial risk of electric
shock, but only a minor risk of electric arcs through air.
The United States 2005 National Electrical Code (NEC) defines low
voltage as any voltage under 600 V
British Standard BS 7671:2008 defines low voltage as
• 50–1000 V AC or 120–1500 V ripple-free DC between conductors;
• 50–600 V AC or 120–900 V ripple-free DC between conductors and Earth.
The International Electrotechnical Commission defines low voltage as
any voltage in the range 50–1000 V AC or 120–1500 V DC
IEC Voltage Standard and Recommendation
Definition of Low Voltage :
Where two voltages are given below separated by “/”, the first is the rootmean-square voltage between a phase and the neutral connector, whereas
the second is the corresponding root-mean-square voltage between two
phases. The three-phase voltages are for use in either four-wire (with
neutral) or three-wire (without neutral) systems.
Three-phase 50 Hz
• 230 V / 400 V
• 400 V / 690 V
• 1000 V
Suppliers using 220 V / 380 V or 240 V / 415 V systems were
expected by the standard to migrate to the recommended value of
230 V / 400 V by the year 2003. This migration has already been
largely completed, as least within the European Union.
IEC Voltage Standard and Recommendation
Definition of Extra Low Voltage :
The International Electrotechnical Commission and its member organizations
define an ELV circuit as one in which the electrical potential of any conductor
against earth (ground) is not more than either 50 volts RMS (70 volts peak)
for alternating current, or 120 volts for direct current.
TNB Supply Schemes
TNB customers are connected with power from hydroelectric and thermal
plants through a network system made up of transmission lines, substations
and distribution lines. Through this system, TNB supplies electricity to
customers consistently and continuously by ensuring a balance between
demand and supply at all times.
TNB Supply Schemes
TNB Supply Schemes
Hydroelectric Power Plants
The basic concept behind hydroelectric power generation is the
utilization of energy from flowing water as it descends from a height,
where potential energy is converted to electrical energy. A hydroelectric
power station requires a means of conveying water to produce the force
necessary to spin a turbine linked to an electric generator, usually
through a conduit such as a pipeline or tunnel to a turbine-generator
which is spun by the passing water. TNB hydroelectric power stations
are classified as either storage, run-of-river.
There are 3 hydroelectric schemes with installed generating capacity of
1,911 MW with 21 dams in operation :
1. Sungai Perak hydroelectric scheme, with 1,249 MW installed capacity.
2. Terengganu hydroelectric scheme, with 400 MW installed capacity
3. Cameron Highlands hydroelectric scheme, with 262 MW installed
capacity.
TNB Supply Schemes
Thermal Power Plant
TNB’s thermal plants produce power using conventional steam
and steam generator principally fired by coal, oil or natural gas
power plant), gas-fired or diesel-fired open cycle gas
generators, and gas-fired or diesel-fired combined cycle
generators.
turbine
(steam
turbine
turbine
There are 6 major thermal power plants with installed generating
capacity of 4,435 MW in operation, plus 3 thermal plants with 4,950 MW
operated as IPP plants.