In the process of supplying electricity to
consumers, technical losses occur naturally and consist mainly of power
dissipation in electricity system components such as transmission and
distribution (T&D) lines, transformers, and measurement systems. T & D
losses have I2R losses as a major component, and if one can reduce the
resistance,the losses can be reduced.So, while resistance depends upon metal
area and its resistivity,there is a need to improve both without changing the
physical area of the conductor. This is besides improving compaction % i.e.
Metal area/Physical area. Also, normal compacted conductors have a compaction
of 87-91% causing a limit on metal area that can be fitted inside the physical
area. These issues have been sorted by a unique design using 2 layers of
trapezoidal wires. The electricity sector in India had an installed capacity of
205.34 Gigawatt (GW) as of June 2012, the world's fifth largest. Captive power
plants generate an additional 31.5 GW. Thermal power plants constitute 66% of
the installed capacity, hydroelectric about 19% and rest being a combination of
wind, small hydro, biomass, waste-to-electricity, and nuclear. India generated
855 BU (855 000 MU i.e. 855 TWh) electricity during 2011-12 The per capita
average annual domestic electricity consumption in India in 2009 was 96 kWh in
rural areas and 288 kWh in urban areas for those with access to electricity, in
contrast to the worldwide per capita annual average of 2600 kWh and 6200 kWh in
the European Union. India's total domestic, agricultural and industrial per
capita energy consumption estimates vary depending on the source. Two sources
place it between 400 to 700 kWh in 2008–2009. As of January 2012, one report
stated that the per capita total consumption in India to be 778 kWh. In terms
of fuel, coal-fired plants account for 56% of India's installed electricity
capacity, compared to South Africa's 92%; China's 77%; and Australia's 76%.
After coal, renewal hydropower accounts for 19%, renewable energy for 12% and
natural gas for about 9%. Further, the 17th electric power survey of India
report claims: In December 2011, over 300 million Indian citizens had no access
to electricity. Over one third of India's rural population lacked electricity,
as did 6% of the urban population. Of those who did have access to electricity
in India, the supply was intermittent and unreliable.
In 2010, blackouts and power shedding
interrupted irrigation and manufacturing across the country. The per capita
average annual domestic electricity consumption in India in 2009 was 96 kWh in
rural areas and 288 kWh in urban areas for those with access to electricity, in
contrast to the worldwide per capita annual average of 2600 kWh and 6200 kWh in
the European Union. India's total domestic, agricultural and industrial per
capita energy consumption estimates vary depending on the source. Two sources
place it between 400 to 700 kWh in 2008–2009. As of January 2012, one report stated
that the per capita total consumption in India to be 778 kWh.
DEMAND TRENDS As in previous
years, during the year 2010–11, the demand for electricity in India far
outstripped availability, both in terms of base load energy and peak
availability. Base load requirement was 861,591 (MU[) against availability of
788,355 MU, a 8.5% deficit. During peak loads, the demand was for 122 GW
against availability of 110 GW, a 9.8% shortfall. In a May 2011 report, India's
Central Electricity Authority anticipated, for 2011–12 year, a base load energy
deficit and peaking shortage to be 10.3% and 12.9% respectively. The peaking
shortage would prevail in all regions of the country, varying from 5.9% in the
NorthEastern region to 14.5% in the Southern Region. India also expects all
regions to face energy shortage varying from 0.3% in the North-Eastern region
to 11.0% in the Western region. India's Central Electricity Authority expects a
surplus output in some of the states of Northern India, those with
predominantly hydropower capacity, but only during the monsoon months. In these
states, shortage conditions would prevail during winter season. According to
this report, the five states with largest power demand and availability, as of
May 2011, were Maharashtra, Andhra Pradesh, Tamil Nadu, Uttar Pradesh and
Gujarat.
According to 17th EPS
Over 2010–11, India's industrial
demand accounted for 35% of electrical power requirement, domestic household
use accounted for 28%, agriculture 21%, commercial 9%, public lighting and other
miscellaneous applications accounted for the rest. The electrical energy demand
for 2016–17 is expected to be at least 1392 Tera Watt Hours, with a peak
electric demand of 218 GW. The electrical energy demand for 2021–22 is expected
to be at least 1915 Tera Watt Hours, with a peak electric demand of 298 GW.
Also, if the current average transmission and distribution average losses is
around 32% then India needs to add about 135 GW of power generation capacity,
before 2017, to satisfy the projected demand after losses. Item Value Date
Reported Total Installed Capacity (GW) Available base load supply (MU) Demand
base load (MU) Demand base load (GW) Available base load supply (GW) 201.64
837374 118.7 933741 136.2 April 2012 May 2011 May 2011 May 2011 May 2011
Electricity sector capacity and availability in India (excludes
McKinsey claims that India's
demand for electricity may cross 300 GW, earlier than most estimates. To
explain their estimates, they point to four reasons: sterlitetechnologies.com
India's manufacturing sector is likely to grow faster than in the past Domestic
demand will increase more rapidly as the quality of life for more Indians
improve About 125,000 villages are likely to get connected to India's
electricity grid Currently blackouts and load shedding artificially suppresses
demand; this demand will be sought as revenue potential by power distribution
companies THE CAUSE FOR LOSSES A demand of 300GW will require about 400 GW of
installed capacity, McKinsey notes. The extra capacity is necessary to account
for plant availability, infrastructure maintenance, spinning reserve and
losses. India currently suffers from a major shortage of electricity generation
capacity, even though it is the world's fourth largest energy consumer after
United States, China and Russia. The International Energy Agency estimates
India needs an investment of at least $135 billion to provide universal access
of electricity to its population. The International Energy Agency estimates
India will add between 600 GW to 1200 GW of additional new power generation
capacity before 2050. This added new capacity is equivalent to the 740 GW of
total power generation capacity of European Union (EU- 27) in 2005. The
technologies and fuel sources India adopts, as it adds this electricity
generation capacity, may make significant impact to global resource usage and
environmental issues. India's network losses exceeded 32% in 2010 including
non-technical losses, compared to world average of less than 15%. Both
technical and non-technical factors contribute to these losses, but quantifying
their proportions is difficult. Some experts estimate that technical losses are
about 15% to 20%, a high proportion of non‐technical losses are caused by
illegal tapping of lines, but faulty electric meters that underestimate actual
consumption also contribute to decrease in payment collection. A case study in
Kerala estimated that replacing faulty meters could reduce distribution losses
from 34% to 29%.
In 2010, electricity losses in India during
transmission and distribution were about 24%, while losses because of consumer
theft or billing deficiencies added another 10–15%. Power cuts are common
throughout India and the consequent failure to satisfy the demand for
electricity has adversely effected India's economic growth. SUSTAINABLE OPTIMAL
REDUCTION OF TECHNICAL LOSSES Optimization of technical losses in electricity
transmission and distribution grids is an engineering issue, involving classic
tools of power systems planning and modeling. The driving criterion is
minimization of the net present value (sum of costs over the economic life of
the system discounted at a representative rate of return for the business) of
the total investment cost of the transmission and distribution system coupled
with the total cost of technical losses.Technical losses are valued at
generation costs. Technical losses represent an economic loss for the country,
and its optimization should be performed from a country's perspective,
regardless of the institutional organization of the sector and ownership of
operating electricity utilities. LOSSES - RESISTIVE Transmitting electricity at
high voltage reduces the fraction of energy lost to resistance, which averages
around 7%. For a given amount of power, a higher voltage reduces the current
and thus the resistive losses in the conductor. For example, raising the
voltage by a factor of 10 reduces the current by a corresponding factor of 10
and therefore the I2R losses by a factor of 100, provided the same sized
conductors are used in both cases. Even if the conductor size (cross-sectional
area) is reduced 10-fold to match the lower current the I2R losses are still
reduced 10-fold. Long distance transmission is typically done with overhead
lines at voltages of 115 to 1,200 kV. STERLITE's SOLUTION Sterlite ULTRAEFF low
loss MV Power Cables consist of conductor made from very compactly packed
trapezoidal cross-section aluminium strands which are prepared from specially
treated aluminium having improved conductivity, high performance XLPE
insulated, armoured and unarmoured power cables as per IS-7098-PII and
equivalent standards.
METHODS TO REDUCE RESISTANCE As
resistance of a conductor is dependent on resistivity, length and area, we can
improve the resistance by following: Improving the conductivity of aluminium by
annealing and heat treatment. The metal is heat treated for a preset amount of
time at a preset temperature improving the conductivity to 62.5 %. 1) Putting
more metal area in the same physical area by improving the compaction of the
conductor. 2) A stranded circular compacted conductor is made of wires,
stranded and compacted to a form of conductor.Two methods of conductor making
are prevalent: die compaction with a maximum possible compaction of 90-91 %,
Roller compaction for sizes of 240 sq.mm and above with a max possible
compaction of 92- 93%. This leads to presence of air gaps and limits the amount
of metal area that can be put in the same physical area. If trapezoidal wires
are used in place of circular wires, this compaction can be increased to 97 %
increasing the metal area and thus effectively reducing the resistance and
hence the losses. Sterlite with its background in metallurgy and conductor
making adapted this concept for overhead conductors as well as underground cables.
With enhanced conductivity and higher compaction, 300 sq.mm conductor with
trapezoidal wires was produced to have a conductor resistance of 87% value of
that specified by IS 8130.
Lower I2R losses for the
transmission /distribution network for the same transmitted current. Higher
current rating for conductor temperature of 900C. Higher short circuit rating
because of higher metal area in the conductor. CONCLUSION With the extensive
use of electricity, and the wide geographical distribution of users, an
effective transmission and distribution system is essential. The history of
electricity transmission can be dated back to 1883, when Thomas Edison first
introduced an economically viable model for generating and distributing
electric power. Edison's greatest achievement was perhaps not the invention of
the light bulb or any other single application, but the universally applicable
electricity transmission system which has lit up the whole world. Modern
electrical transmission and distribution systems are the result of
conscientious efforts and design skills of engineers to ensure high energy
efficiency and safety. Thus, high energy efficiency means the loss of power
through transmission is minimized.[ Pranav Vasani is Head –
Quality Assurance, Power Cables Business, Sterlite Technology & courtesy-sterlitetechnologies.com]
No comments:
Post a Comment