Technology to reduce T&D Loss [May 2012]

Power-hungry India losses almost one-third of its electricity generated. Ashok Kaushik, Vice President (India Operations) at ENSTO India explores the effective ways of handling T&D loss
India is the quick mounting electricity market in the world, with demand expected to amplify by around 500 per cent over the next four decades. The Indian power sector faces major challenges in trying to meet the continuously expanding demand-supply gap. The most important factor is that India’s electricity sector has the highest transmission and distribution losses in the world. In recent years, around one-third of electricity generation has been lost during the transmission and distribution phase.
Very less point of transmission and distribution losses, system reliability, redundancy of protection and communications are the essential factors for a power system. It is indeed alarming to know the level of losses in Indian electricity field. Conservation strategies like enhancing the electricity consumption efficiency, tariff based on principle of marginality for electricity consumption particularly for the agriculture sector could be undertaken without affecting the high growth that the country is currently experiencing and is expected to experience in future. Also in case of India, by reducing transmission and distribution losses, more electricity from the existing installed capacity could be brought into the grid. By adopting different energy conservation measures through efficient management, energy related pollution and emissions can be limited and more energy made available for economic productivity.
Upgrading out-of-date transmission and distribution systems coupled with the need to reduce electricity losses and theft is driving the deployment of smart grid technologies in India. The real challenge in the power sector in India lies in managing the up-grading of the transmission, distribution and metering efficiently. In response to these challenges, India will look to foreign technology suppliers for the following:• Advanced metering to reduce AT&C (Aggregate Technical and Commercial) losses that are currently at high levels• Automation to measure and control the flow of power to/from consumers on a near real-time basis and improve the system reliability• Moving to a smart grid to manage loads, congestion, and supply shortages in an intelligent manner.
Electrical power generated in power stations reaches the end-users through large and complex networks. The power system networks comprise transformers, overhead lines, cables and other equipment to facilitate the transfer of electricity to consumers. Hard fact about the supply of electric energy is that the units generated do not match with the units distributed to the consumers. Some percentage of the units is always lost in the network. This difference in the generated and distributed units is known as energy loss.
Losses can be divided into two main categories – technical and commercial losses. The technical losses are due to energy dissipated in the conductors and equipment used for transmission, transformation, sub-transmission and distribution of power. Corona, leakage, dielectric losses, open-circuit losses, losses caused by continuous load of measuring elements, losses caused by continuous load of measuring elements are the main permanent technical losses. Main variable technical losses are joule losses in lines in each voltage level, impedance losses, losses caused by contact resistance, joule losses in protection components.
To minimise technical losses there are two directions. One is, with investments on 110 V, 230 V, 6 kV, 22 kV lines. This includes PF correction (compensation), replacement of current lines to higher diameter lines; replacement of old damaged lines to new ones. The use of better materials in electrical equipment will definitely enhance power efficiency. Without investment methods include advisable distribution of reactive power, advisable load of lines, decrease peak power etc.
Inadequate size of conductors causes large resistance and therefore high I2R losses in the lines. The conductor size of feeders should be adequate. The size of the conductors should be selected on the basis of KVA X KM capacity of standard conductor for required voltage regulation. Often distribution transformers are not located at load centre on the secondary distribution system. This leads to higher line losses. In order to reduce the voltage drop in the line to the farthest area, the distribution transformer should be located at the load centre to keep voltage drop within permissible limits.Joints are a source of power loss. Therefore the number of joints should be kept to a minimum. Proper jointing techniques should be used to ensure firm connections. Connections to the transformer bushing-stem, drop out fuse, isolator, and LT switch etc. should be periodically inspected and proper pressure maintained to avoid sparking and heating of contacts. Replacement of deteriorated wires and services should also be made timely to avoid any cause of leaking and loss of power.
Commercial losses are mainly due to:• Unauthorised extensions of loads, especially those having ‘H.P.’ tariff• Tampering the meter readings by mechanical jerks, placement of powerful magnets or disturbing the disc rotation with foreign matters and stopping the meters by remote control• Sequence changing of terminal wiring• Changing C.T. ratio and reducing the recording• Improper testing and calibration of meters.
For preventing these losses important remedial measures are as follows:• Regular and strict checking of energy meters and extension lines • High penalties may be imposed on thefts• Energy audits should be introduced on regular basis.
Network losses can be reduced by designing the network system in such a way that to make power lines to large consumers as direct as possible and reducing the number of transformation steps. Transformers are account for half of the total network losses, so that they should be highly energy efficient. When storage near a load is charged off peak, the total resistive losses over the period of a day are reduced. The benefit is the total cost of the extra energy generated and the cost of extra generation and transmission capacity.  For the promotion of the remedial activities Govt. should provide financial support to the utilities for installations of meters on at least all the distribution transformers in a phased manner. Govt. should also take initiative for incentive awards to utilities that are able to reduce T&D losses beyond a certain pre-fixed limit. The important point is the consumer awareness. Publicity campaigns should be carried out to make the consumer aware of the high penalties on the unauthorised use of electricity.
Recently, the Govt. of India sought South Korea’s help to take forward its ` 5,000 crore Restructured Accelerated Power Development and Reforms Programme (R-APDRP), which primarily aims at making the power distribution sector commercially viable through reduction of transmission and distribution loss. Korea has the most efficient technology in managing T&D loss. While India’s average T&D loss at present was 29 per cent, Korea’s was only 3.99 per cent. In fact, International Copper Promotion Council (India) found that copper reduces T&D losses better than aluminium, based on this the government decided to allow the use of copper in distribution transformers (DTs).
Given the socio-political scenario in India, it is time for India to introspect about strict measures to minimise the T&D losses caused by several factors and implement smart grid technologies as a model for power distribution and consumption. It should include smart meters, electric vehicles and other such systems that will enable reduce T&D losses and access of power to rural areas and reliability and quality of power to urban areas.
There are many benefits of reduced T&D losses; energy efficient countries can gain a competitive advantage over less efficient countries, allowing them to increase their profits. Environmental benefits include many, such as reduced local pollution through burning less fuel, lower greenhouse gas emissions, less use of firewood and hence less destruction of forests. Even where country output is increased (e.g. through expanding manufacturing capacity) energy efficiency improvements can contribute significantly in most cases to reducing the negative impact of energy consumption per unit of output. Any increase in pollutant emissions will thus be minimised and also can meet demands and thereby customer satisfaction.
About ENSTO India Pvt Ltd A 100 per cent subsidiary of ENSTO Finland Oy. Founded in 2009, Ensto India product line is adapted to the local needs. The company offers solutions for low voltage overhead & underground lines; solutions for medium voltage overhead & underground lines; high-end industrial enclosure & terminal solutions – plastic & metal; customer training and technical support. Ensto India unit has received ISO 9001:2008 certificate.

Click to comment

You must be logged in to post a comment Login

Leave a Reply

Most Popular

To Top