Transmission of Electricity
by Harsha Rajwanshi
Experts CornerGUVNL - GNLU
Published on January 24, 2018 By Saba
The usual flow of electricity to the consumer is from the generating plant into transmission system through distribution system. Electric transmission systems act as tie point with interconnecting transmission lines structured by all high pressure cables and overhead lines transmitting high voltage power in bulk quantities from power generating source to delivery substations, where step-down transformers convert electricity in different power levels for supply of power to residential, commercial, and industrial consumers.
Transmission lines provide interconnections for the transfer of power between utilities using the wheel-barrowing of power. This integrated high voltage backbone system of interconnected transmission lines, substations and generating plants is commonly referred to as grid. National Grid procures balancing services in order to balance demand and supply and to ensure the security and quality of electricity supply across the transmission system for distribution.
Essentially, the grid coordinate system divides any particular area served into a number of small areas in a grid pattern by superimposing on a map a system of grid lines. Ergo the country has been demarcated into five electrical regions viz. Northern (NR), Eastern (ER), Western (WR), Southern (SR) and North Eastern (NER). However, NR, ER, WR and NER have been synchronously interconnected and operating as single grid — Central Grid with the capacity of 110,000 MW. The Southern region is asynchronously connected to the Central Grid through HVDC links.
All the five regions interconnected through National Grid are comprised with hybrid AC/HVDC system. Each regional grid is handled by the Regional Load Dispatch Centre, RLDC. The State grids are managed and operated by State Load Despatch Centre (SLDC). National Load Despatch Centre (NLDC) is for scheduling and despatch of electricity across various regions and also coordinating cross border energy exchanges in real time.
Power Grid Corporation of India Ltd. (Powergrid) is the Central Transmission Utility (CTU) responsible for wheeling power of central generating utilities and inter-state Mega IPPs, while State Transmission Utilities are responsible for wheeling of power from State generating units and State level IPPs. The intervening utilities are compensated for the use of their facilities. Control centres owned by different utilities collaborate with each other for executing their statutory responsibility of ensuring a secure, reliable, efficient and economic power system operation.
Transmission Planning
Following National Electricity Policy, the Central Electricity Authority (CEA) in August 2014 has prepared the perspective National Transmission Plan 2014-2034 in association with CTU and Power System Operation Corporation Ltd. (Posoco). The plan is based on demand forecast, presenting a broad outline of the requirement of transmission system in the Indian grid for the next 20 years. The all-India peak demand is expected to rise from the current level of 153 GW to about 690 GW i.e. more than four times by 2035-36. This implies roughly quadrupling the generation installed capacity as well as transmission systems of about 4 to 5 times the present capacities. The plan is prepared on the basis of power flow studies, contingency studies, short circuit, dynamic and voltage stability studies and techno-economic analysis. CEA is also working on 19th Electric Power Survey Report. An Advance National Transmission Plan for year 2021-22 has also been prepared by CEA and submitted to the Ministry of Power in the year 2016.
The object of transmission plan is to meet the reliable evacuation of power in an optimum manner conserving the right-of-way, providing for delivery points near load centres, having adequate margins for trading of electricity and using the best technological options.
Electricity Act, 2003
The Electricity Act, 2003 (EA, 2003) incorporates laws pertaining to transmission of electricity and encourages participation of private sector over this bailiwick. Section 9 clearly expresses that the supply of electricity from the captive generating plant through the grid shall be regulated. Any person managing such plant shall have the right to open access for the purposes of carrying electricity from his captive generating plant to the destination of his use, subject to availability of adequate transmission facility determined by CTU or State Transmission Utility (STU) as the case may be, and any dispute regarding the availability of transmission facility shall be adjudicated upon by the appropriate Commission. Under Section 10(3) it is obligatory for every generating company to coordinate with the CTU or STU for transmission of the electricity generated by it.
Transmission is a licensed activity. Under Section 14 EA, 2003 the appropriate Commission may, on an application made to it under Section 15, grant a licence to any person to transmit electricity as a transmission licensee in any area as may be specified in the licence. However, the CTU, STUs and the appropriate Government engaged in transmitting electricity are deemed to be transmission licensee under the law. Every transmission licensee has to comply with such technical standards, of operation and maintenance of transmission lines, in accordance with the Grid Standards, as may be specified by the Electricity Authority under Section 34. It shall be the duty of a transmission licensee to build, maintain and operate an efficient, coordinated and economical inter-State transmission system or intra-State transmission system under Section 40.
Section 25 EA, 2003 casts a duty upon the Central Government to facilitate voluntary interconnections and coordination of facilities for the inter-State, regional and interregional transmission of electricity. The Central Government may under Section 26 establish NLDC at the national level for optimum scheduling and despatch of electricity among the RLDC constituted under Section 27(1) having territorial jurisdiction as may have been determined for the purposes of exercising the powers and discharging the functions of transmission of electricity. Section 28 designates RLDC as the apex body to ensure integrated operation of the power system of the region concerned and shall comply with such principles, guidelines and methodologies in respect of the wheeling and optimum scheduling and despatch of electricity as the Central Commission may specify in the Grid Code. RLDC has been made responsible for carrying out real time operations for grid control through secure and economic operation. Section 30 mandates the State Commission to facilitate and promote intra-State transmission by constituting SLDC to be established by the State Government under Section 31 EA, 2003.
Sections 38 and 39 EA, 2003 evolve CTU and STUs to undertake transmission of electricity through intra-State transmission system, discharge all functions of planning and coordination to ensure development of an efficient, coordinated and economical system of intra-State transmission lines for smooth flow of electricity from a generating station to the load centres.
Sections 61 and 62 EA, 2003 make incumbent upon the appropriate Commission to specify the terms and conditions and to determine the tariff for transmission of electricity. Under Section 79 the Central Commission has to regulate the inter-State transmission of electricity and adjudicate upon disputes involving the transmission licensee and to refer any dispute for arbitration while Section 86 obliges the State Commission to facilitate intra-State transmission and wheeling of electricity.
The Central Electricity Authority under Section 53 has to specify suitable measures for protecting the public from dangers arising from transmission of electricity and shall intimate in the specified form to the appropriate Commission and the Electrical Inspector, of accidents and failures of transmissions of electricity and ensure that maps and plans relating to supply or transmission of electricity are kept by the generating company or licensee.
Transmission bottlenecks
Inadequate transmission infrastructure
The power sector in India has seen remarkable transformation in recent years in the area of generation. However, a major obstacle on the way is the failure of the transmission sector to adapt to the rapid changes occurring in the system. Many independent power producers are unable to supply electricity to power-starved States. Lack of transmission capacities ramifies wastage of electricity. Inadequate transmission infrastructure deprives consumes of electricity and also results in power plants being forced to shut down or operate at low plant load factors. Failure in evacuating requisite power sporadically results in gridlock. Utilities erratically wrest more power and transmission infrastructure is unable to support such huge transmission of electricity, consequently grid collapse evolving blackout, affecting masses.
Paucity of space
Narrow corridors like chicken neck, multiple EHV lines have created congestion around existing substations, leaving almost no space for the future expansion. Similarly metros and densely populated cities have created serious problems for getting new corridors. The key transmission interregional and other despatch corridors are in perpetual deficit in inter-State system and more in intra-State transmission network.
Right of Way (RoW)
The Right of Way (RoW) is at present the most notable issue which is being faced by the transmission sector. An electric transmission line right-of-way (RoW) is a strip of land used by electrical utilities to construct, operate, maintain and repair the transmission line facilities. The width of a right-of-way depends on the voltage of the line and the height of the structures. This is now the grey area for development of transmission system. The most challenging is land acquisition, regulatory and environmental clearances for the transmission lines. Increased awareness of farmers, landowners, reserved forest, bird sanctuaries, religious structures; it has become increasingly difficult to get smooth and timely RoW clearances. Some of the transmission lines have been waiting to be commissioned for long time since small sections are stuck up due to forest clearances and some locations are in dispute.
Lack of competition and private participation
State-owned Power Grid Corporation of India Ltd. (Pgcil) is exercising monopoly over the sector. The transmission sector is devoid of full-blown competition and private participation leading to major constraint in flow of power and impediment in growth of the sector. Deficit power evacuation infrastructure is attributable to investment lag, private sector in particular. Private participation is either crimped or is stunted. Clearance processes are different for private players. In transmission PPP, almost all risks are placed with the project developer and public partner is entrusted with mere facilitation.
The latest performance report of the Power Ministry states that the transmission network in the country had increased 40% to 7.4 lakhs MVA in March 2017, from 5.3 lakhs MVA in March 2014. Still transmission constraints have to be addressed upfront to improve the chances of reaping the long-term rewards of effective contribution to the power mix. The transmission is not only an enabler for power but also is the multiplier of a competitive power market as well as basic parameter of power price sensitivity. It is essential to work upon UHV lines and develop high intensity transmission corridor (MW per meter RoW) in an environment friendly manner including protection of flora and fauna. More and more condition based technology needs to be used to avoid forced outage and reduce the maintenance requirement and quick restoration of faulty system. Variable power demand has to be regulated with flexibility in line loading. Judicious use of skilled manpower and their redeployment require more attention. Monopoly regime in the transmission sector deserves to be dismantled. Power transmission system is required to be operated at the rated capacity with security, reliability and high availability. This can only be achieved through reliability based online condition monitoring, repair and maintenance in advance and making forced outage as zero.
*Harsha Rajwanshi is the Assistant Professor of Law, Gujarat National Law University & Faculty Advisor to GUVNL-GNLU Research Fellowship on Energy Law and Policy.
Written by Saba
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Rohan Rao Feb 25, 2019
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