Electricity plays a vital role in our day-to-day life. It powers our houses, industries, hospitals and in fact our entire economy. Historically speaking the modern electricity industry utility system was first introduced to the world on the opening of Thomas Edison’s Pearl Street Electricity Generating Station on September 4th , 1882 at New York (United States of America).
Insofar as Delhi is concerned, the position is that as per available records, the first diesel Power Station was established in Delhi in the year 1905 when a private English Company by name M/s. John Fleming was given permission to generate electricity under the provisions of the Indian Electricity Act 1903. The above mentioned Company was given the responsibility both of generation and distribution of power in a limited manner. That Company after obtaining license under the provisions of Electricity Act 1903 had set up a small 2 MW Diesel set at Lahori Gate in Old Delhi.
Later on, this very Company was converted as Delhi Electricity Supply and Traction Company. In the Year 1911, the power generation was augmented by Steam Generation Station. In the year 1932, the management of Central Power House was handed over to New Delhi Municipal Committee (NDMC). In the field of power generation and distribution, a major break through was achieved in 1939 when Delhi Central Electricity Power. A uthority (DCEPA) was established.
This Company was responsible for the supply of power to the areas covered by Local Bodies, namely, the Municipal Committees of Delhi, West Delhi and South Delhi, the Notified Area Committees of Red fort, Civil Lines, Mehrauli, Najaf Garh, amd the District Board of Delhi. The supply of electricity to the Municipal Committees of Delhi-Shahdara and the Notified Area of Narela was done by different private agencies. In 1947 DCEPA took over a Private Limited Company by name Delhi electric Supply traction Company Limited.
In the year 1948, electricity (Supply) Act 1948 came into force, which inter-alia provided for the constitution of an electricity Board in the States that was to function as a vertically integrated electricity utility in the entire State, undertaking all the functions of activities related to electricity, which included electricity generation, transmission, distribution, supply, planning coordination and also was to act as regulatory authority for carrying out other functions incidental and ancillary thereto.
In other words, the Electricity (Supply) Act 1948 was entitled to become a monopolistic undertaking in the field of electricity control by an instrument of the state and not by private sector. The principal objective behind the above policy decision of the Government of India in providing for the constitution of State electricity to all, particularly in semi-urban and rural areas because till then the availability of electricity was confined to urban areas and was mainly served by private electricity distribution licenses issued under the Indian electricity Act 1910. Formation of Delhi State Electricity Board.
In pursuance of the provisions of the Electricity (Supply) Act, 1948, in Delhi, in the year 1951 the Delhi State Electricity Board (DSEB) came into existence and the responsibility of generation and distribution of electricity was taken over by DSEB from DCEPA. The entire staff of DCEPA and other agencies was absorbed by DSEB under the existing terms conditions of service.
Thus, starting the humble origin, i. e. , Private Limited Company having a few employees with primitive generation process, the generation, transmission, and distribution of power to the citizens of Delhi has now come in the hands of above mentioned six Companies with an employee strength which has grown over the years from a meager figure of few hundred to about 20,000. Prior to 1951, the demand of power in Delhi was about 27 MW which now has grown to about 4,000 MW.
Availability of reliable and cheap power is absolutely essential for economic development of any developing society and consumption of electricity is an important indicator of the stage of development of agriculture, industry and commerce. With the growth of population, industries, importance of Delhi being the national Capital and with the advancement of technology, life style and increased use of new electrical electronic gadgets, the demand of power has gone up enormously.
The role of Delhi Transco Limited is confined to arrange and provide transmission network of 400 KV and 220 KV source from Northern Grig. The present infrastructure for this purpose under 400 KV system is 4,725 MVA (2520 MVA with DTL and 2205 with Power Grid Corporation). As against this, 220 KV sub Stations have the capacity of 6,300 MVA is available for Delhi. Future Plans In the 11th Plan ending 2011-12 the transmission capacity is proposed to be augmented to meet the future requirements.
Under 400 KV system, it is proposed to establish new Sub Stations at Mundka, South-East Delhi near Mandi village and East Loni Road with a capacity of 630 MVA each by DTL and also increase the capacity of existing sub-Station at Maharani Bagh by 630 MVA b Power Grid Corporation of India Limited. Similarly, under 220 KV system, augmentation and new addition in capacity to the tune of 1660 MVA under the existing Sub Stations is proposed. Further, new Sub Station at DSIDC Bawana-II (320MVA), Chandrawal (200 MVA), Jhatikara More (320 MVA),.
Ridge Valley (320 MVA), Rohini-II (480 MVA), Sultanpuri (320 MVA), Electric lane (200 MVA), Trauma Centre (200 MVA), Wazirpur Industrial Area (320 MVA) and IGI Airport (320 MVA ) are proposed to be established. Thus, the capacity of 2520 MVA and 5940 MVA will be added in the 400 KV system and 220 kv substation respectively. To sum up, by 2011-12 transformation capacity of 8460 MVA will be added and a total capacity of 19485 MVA will be available to Delhi.
Delhi Transco Limited, a successor company of erstwhile Delhi Vidyut board, came into existence on 1st July 2002, as a State Transmission Utility of the National Capital. After unbundling of DVB the distribution sector has been handed over to private companies while the generation and transmission are still with the government. Over the years, DTL has evolved as a most dynamic performer, keeping pace with the manifold challenges that confront the ever ncreasing demand-supply power situation and achieving functional superiority on all fronts.
Being the capital of India and the hub of commercial activities in the Northern Region, coupled with the prosperity of population, the load requirement of Delhi has been growing at a much faster pace. Added to that, being the focus of socio-economic and political life of India, Delhi is assuming increasing eminence among the great cities of the world. Plus the vgision-2021, aiming to make Delhi global Metro politic and world class city demand greater infrastructure to enrich many services of infrastructure development. DTL has been responsibly playing its role in establishing.
Upgrading, operating and maintaining the EHV (Extra High Voltage) network. DTL has also been assigned the responsibility of running the State load Dispatch Centre (SLDC) which is an apex body to ensure integrated operations of power system in Delhi. Delhi Transco is also committed to promote energy conservation not only in its own establishments but also in the entire Delhi. The company has done a lot to educate and sensitize the general public about the need of energy conservation.
Transmission loss level has been reduced from 3. 84 per cent in 200-203 to 1. 8 per cent in 2009-10, which is one of the lowest transmission loss level in the country. To ensure adequate and efficient power supply. DTL has been continuously upgrading its biggest achievement has been its ability to handle the highest ever peak demand of 4720 MW in July 2010. The total availability of its transmission system stood 98. 78%. The modern technologies are being implemented in DTL by way of constructing GIS sub stations and laying XLPE 220 KV cable by employing cable link techniques and would be the largest network of its kind in India.
DTL operate its obligations in a clean, green pollution free environment and has been providing more green coverage to the National Capital. It has contributed a lot in spreading awareness among the masses to use eco-friendly electrical appliances. The Energy Conservation Building Code also thrust upon to maximize the use of natural resources and minimize the use of electricity. Transparency and AccountabilityDelhi Transco Ltd. is committed to provide information to the citizens with a view to fulfill it obligations under Delhi Right to information Act 2001 and Right to Information Act 2005.
Anyone desirous of seeking information related to the functions of the company can ask for information. Apart from this a transparent mechanism has been put in place for award of the works and release of payments to the contractors and other stake holders. To enhance efficiency and productivity, DTL has initiated several IT based projects. For constant access to real-time data of the entire network, the company has implemented Supervisory Control and Data Acquisition (SCADA) systems. DTL has also carried out system studies, adopting state of the art software.
Enterprise Resources Planning Software has been implanted which offers an integrated software facilitates best practice by creating more efficient system and concentrating its efforts towards maximizing profits. DTL has achieved a commendable financial turnaround after a four-year financial engineering process. It has posted profits in each of the past 4 years. In 2009-10 DTL profits, after tax stood at Rs. 77. 28 Crore, an impressive 21. 72% increase over the Rs. 63. 49 Crore, registered in the Government and Rs. 54 lacs DPCL for 2009-10.
In the 11th Plan ending 2011-12 the transmission capacity is proposed to be augmented to meet the future requirements. Under 400 KV system, it is proposed to establish new Sub Stations at Mundka, South-East Delhi near Mandi village and East Loni Road with a capacity of 630 MVA each by DTL and also increase the capacity of existing sub-Station at Maharani Bagh by 630 MVA b Power Grid Corporation of India Limited. Similarly, under 220 KV system, augmentation and new addition in capacity to the tune of 1660 MVA under the existing Sub Stations is proposed.
Further, new Sub Station at DSIDC Bawana-II (320MVA), Chandrawal (200 MVA), Jhatikara More (320 MVA),. Ridge Valley (320 MVA), Rohini-II (480 MVA), Sultanpuri (320 MVA), Electric lane (200 MVA), Trauma Centre (200 MVA), Wazirpur Industrial Area (320 MVA) and IGI Airport (320 MVA ) are proposed to be established. Thus, the capacity of 2520 MVA and 5940 MVA will be added in the 400 KV system and 220 KV system, respectively.
The present day electrical power system is a. c. i. e. electric power is generated, transmitted and distributed in the form of Alternating current. The electric power is produce at the power station, which are located at favorable places, generally quite away from the consumers. It is delivered to the consumer through a large network of transmission and distribution. At many place in the line of power system, it may be desirable and necessary to change some characteristic e. g. Voltage, ac to dc, frequency p. f. etc. of electric supply.
This is accomplished by suitable apparatus called sub-station for example, generation voltage (11KV or 6. 6KV) at the power station is stepped up to high voltage (Say 220KV to 132KV) for transmission of electric power. Similarly near the consumer’s localities, the voltage may have to be stepped down to utilization level. This job is again accomplished by suitable apparatus called sub-station. About the substation The substation in Gazipur (Delhi Transco Ltd), New Delhi is one of the largest power grids in Delhi.
The most important of any substation is the grounding (Earthing System) of the instruments, transformers etc. used in the substation for the safety of the operation personnel as well as for proper system operation and performance of the protective devices. An earthes system comprising of an earthing mat buried at a suitable depth below ground and supplemented with ground rods at suitable points is provided in the substations. These ground the extra high voltage to the ground. As it is dangerous to us to go near the instrument without proper earth.
If the instruments are not ground properly they may give a huge shock to anyone who would stay near it and also it is dangerous for the costly instrument as they may get damaged by this high voltage. Site Selection & Layout 220KV Substation : 220KV Sub-Station forms an important link between Transmission network and Distribution network. It has a vital influence of reliability of service. Apart from ensuring efficient transmission and Distribution of power, the sub-station configuration should be such that it enables easy maintenance of equipment and minimum interruptions in power supply.
Sub-Station is constructed as near as possible to the load center. The voltage level of power transmission is decided on the quantum of power to be transmitted to the load center. Selection of site Main points to be considered while selecting the site for Grid Sub-Station are as follows:
- The site chosen should be as near to the load center as possible.
- It should be easily approachable by road or rail for transportation of equipments.
- Land should be fairly leveled to minimize development cost.
- Source of water should be as near to the site as possible.
- The sub-station site should be as near to the town / city but should be clear of public places, aerodromes, and Military / police installations.
- The land should be have sufficient ground area to accommodate substation equipments, buildings, staff quarters, space for storage of material, such as store yards and store sheds etc. with roads and space for future expansion.
- Set back distances from various roads such as National Highways, State Highways should be observed as per the regulations in force.
- While selecting the land for the Substation preference to be given to the Govt. land over private land.
- The land should not have water logging problem.
- Far away from obstructions, to permit easy and safe approach termination of high voltage overhead transmission lines.
Equipment in a 220KV Sub-Station : The equipment required for a transformer Sub-Station depends upon the type of Sub-Station, Service requirement and the degree of protection desired. 20KV EHV Sub-Station has the following major equipments. Bus-bar When a no. of lines operating at the same voltage have to be directly connected electrically, bus-bar are used, it is made up of copper or aluminum bars (generally of rectangular X-Section) and operate at constant voltage.
