Power Sector Glossary


Availability Based Tariff (ABT): It comprises of three components: (a) Capacity Charge: towards reimbursement of the fixed cost of the plant, linked to the plant's declared capacity to supply MWs, (b) Energy Charge: to reimburse the fuel cost for scheduled generation, and (c) Unscheduled Interchange Charge: a payment for deviations from schedule, at a rate dependent on system conditions. The last component would be negative (indicating a payment by the generator for the deviation) in case the power plant is delivering less power than scheduled.

Available Transmission Capability (ATC): The transfer capability of the inter-control area transmission system available for scheduling commercial transactions (through long term access, medium term open access and short term open access) in a specific direction, taking into account the network security. Mathematically ATC is the Total Transfer Capability less Transmission Reliability Margin.


Bilateral Transaction: A transaction for exchange of energy (MWh) between a specified buyer and a specified seller, directly or through a trading licensee or discovered at power exchange through anonymous bidding, from a specified point of injection to a specified point of drawal for a fixed or varying quantum of power (MW) for any time period during a month.


Captive Generating Plant (CPP): Means a power plant set up by any person to generate electricity primarily for his own use and includes a power plant set up by any co-operative society or association of persons for generating electricity primarily for use of members of such cooperative society or association.

Central Commission: Means the Central Electricity Regulatory Commission referred to in sub-section (1) of section 76 of Electricity Act 2003.

Central Generating Station (CGS): The generating stations owned by the companies owned or controlled by the Central Government.

Central Transmission Utility (CTU): Central Transmission Utility Means any Government company, which the Central Government may notify under sub-section (1) of Section 38 of the Electricity Act 2003.

Cogeneration: Means a process which simultaneously produces two or more forms of useful energy (including electricity).

Collective Transaction: A set of transactions discovered in power exchange through anonymous, simultaneous competitive bidding by buyers and sellers.

Company: Means a company formed and registered under the Companies Act, 1956 and includes anybody corporate under a Central, State or Provincial Act.

Congestion: Congestion means a situation where the demand for transmission capacity exceeds the Available Transmission Capability.

Connection Agreement: An Agreement between CTU, inter-state transmission licensee other than CTU (if any) and any person setting out the terms relating to a connection to and/or use of the Inter State Transmission System.

Connection Point: A point at which a Plant and/ or Apparatus connects to the Transmission /Distribution System. Connectivity For a generating station, including a captive generating plant, a bulk consumer or an inter-State transmission, licensee Means the state of getting connected to the inter-State transmission system.

Consumer: Means any person who is supplied with electricity for his own use by a licensee or the Government or by any other person engaged in the business of supplying electricity to the public under this Act or any other law for the time being in force and includes any person whose premises are for the time being connected for the purpose of receiving electricity with the works of a licensee, the Government or such other person, as the case may be.


Dedicated Transmission Lines: Means any electric supply-line for point to point transmission which are required for the purpose of connecting electric lines or electric plants of a captive generating plant referred to in section 9 of Electricity Act 2003 or generating station referred to in section 10 of Electricity Act 2003 to any transmission lines or sub-stations or generating stations, or the load centre, as the case may be.

Demand Response: Reduction in electricity usage by end customers from their normal consumption pattern, manually or automatically, in response to high UI charges being incurred by the State due to overdrawal by the State at low frequency, or in response to congestion charges being incurred by the State for creating transmission congestion, or for alleviating a system contingency, for which such consumers could be given a financial incentive or lower tariff.

Demand: The demand of Active Power in MW and Reactive Power in MVAr of electricity unless otherwise stated.

Design Energy: The quantum of energy which could be generated in a 90% dependable year with 95% availability of installed capacity of the station as set out in Techno-Economic Clearance.

Despatch Schedule: The ex-power plant net MW and MWh output of a generating station, scheduled to be exported to the Grid from time to time.

Distribution licensee: Means a licensee authorised to operate and maintain a distribution system for supplying electricity to the consumers in his area of supply.

Distribution system: Means the system of wires and associated facilities between the delivery points on the transmission lines or the generating station connection and the point of connection to the installation of the consumers.

Drawal Schedule: The summation of the station-wise ex-power plant drawal schedules from all ISGS and drawal from regional grid consequent to other long term access, medium term and short term open access transactions.

DVC: The Damodar Valley Corporation established under sub-section (1) of Section 3 of the Damodar Valley Corporation Act, 1948.


Electric line: Means any line which is used for carrying electricity for any purpose and includes (a) any support for any such line, that is to say, any structure, tower, pole or other thing in, on, by or from which any such line is, or may be, supported, carried or suspended; and (b) any apparatus connected to any such line for the purpose of carrying electricity.

Electricity Supply Code: Means the Electricity Supply Code specified under section 50 of Electricity Act 2003.

Electricity System: Means a system under the control of a generating company or licensee, as the case may be, having one or more - (a) generating stations; or (b) transmission lines; or (c) electric lines and sub-stations; and when used in the context of a State or the Union, the entire electricity system within the territories thereof.

Electricity Trader: Means a person who has been granted a licence to undertake trading in electricity under section 12 of Electricity Act 2003.

Electricity: Means electrical energy- (a) generated, transmitted, supplied or traded for any purpose; or (b) used for any purpose except the transmission of a message.

Energy Generated: Energy generation measured at generator terminals.

Entitlement Share: of a beneficiary (in MW / MWh) in the installed capacity/output capability of an ISGS.

Ex-Power Plant: Net MW/MWh output of a generating station, after deducting auxiliary consumption and transformation losses.

Extra High Voltage (EHV): Where the voltage exceeds 33,000 volts under normal conditions, subject, however, to the percentage variation allowed by the Authority.


Force Majeure: Any event which is beyond the control of the persons involved which they could not foresee or with a reasonable amount of diligence could not have foreseen or which could not be prevented and which substantially affect the performance by person such as but not limited to :- a) Acts of God, natural phenomena, including but not limited to floods, droughts, earthquakes and epidemics; b) Acts of any Government domestic or foreign, including but not limited to war declared or undeclared, hostilities, priorities, quarantines, embargoes; c) Riot or Civil Commotion d) Grid’s failure not attributable to the person.

Forced Outage: An outage of a Generating Unit or a transmission facility due to a fault or other reasons which has not been planned.

Franchisee: Means a person authorised by a distribution licensee to distribute electricity on its behalf in a particular area within his area of supply.


Generate: Means to produce electricity from a generating station for the purpose of giving supply to any premises or enabling a supply to be so given.

Generating Company: Generating Company Means any company or body corporate or association or body of individuals, whether incorporated or not, or artificial juridical person, which owns or operates or maintains a generating station.

Generating Station or Station: Means any station for generating electricity, including any building and plant with step-up transformer, switchgear, switch yard, cables or other appurtenant equipment, if any, used for that purpose and the site thereof; a site intended to be used for a generating station, and any building used for housing the operating staff of a generating station, and where electricity is generated by water-power, includes penstocks, head and tail works, main and regulating reservoirs, dams and other hydraulic works, but does not in any case include any sub-station.

Generating Unit: An electrical Generating Unit coupled to a turbine within a Power Station together with all Plant and Apparatus at that Power Station which relates exclusively to the operation of that turbo-generator.

Government company: Shall have the meaning assigned to it in section 617 of the Companies Act, 1956.

Grid Code: Means the Grid Code specified by the Central Commission under clause (h) of sub-section (l) of section 79 of Electricity Act 2003.

Grid Standards: Grid Standards specified by the Authority under clause (d) of the Section 73 of Electricity Act 2003.

Grid: Means the high voltage backbone system of inter-connected transmission lines, sub-stations and generating plants.

Guaranteed Capacity: MW capacity of the generating unit demonstrated during testing and name plated.


High voltage line: Means an electric line or cable of a nominal voltage as may be specified by the Authority from time to time.

Hydro Plant: The complete hydro power generating facility covering all components such as dam, intake, water conductor system, power house etc.


Independent Power Producer (IPP): A generating company not owned/ controlled by the Central/State Government.

Indian Electricity Grid Code (IEGC) or Grid Code: Regulation describing the philosophy and the responsibilities for planning and operation of Indian power system specified by the Commission in accordance with sub section 1(h) of Section 79 of Electricity Act 2003.

Installed Capacity: The summation of guaranteed rated capacity of the generating units at rated head, or the capacity as decided in consultation with the Authority from time to time considering the up-rating, de-rating etc.

Inter State Transmission System (ISTS): Inter-State Transmission System includes i) Any system for the conveyance of electricity by Means of a main transmission line from the territory of one State to another State, ii) The conveyance of energy across the territory of an intervening State as well as conveyance within the State which is incidental to such interstate transmission of energy, (iii) The transmission of electricity within the territory of State on a system built, owned, operated, maintained or controlled by CTU.

Inter-State Generating Station (ISGS): A Central generating station or other generating station, in which two or more states have shares.

Intra-State transmission system: Means any system for transmission of electricity other than an inter-State transmission system.


Licence: Means a licence granted under section 14 of Electricity Act 2003.

Licensee: Licensee means a person who has been granted a license under Section 14 of Electricity Act 2003.

Line: Means any wire, cable, tube, pipe, insulator, conductor or other similar thing (including its casing or coating) which is designed or adapted for use in carrying electricity and includes any line which surrounds or supports, or is surrounded or supported by or is installed in close proximity to, or is supported, carried or suspended in association with, any such line.

Load: The MW/MWh consumed by a utility/ installation.

Long–Term Access: The right to use the inter-State transmission system for a period exceeding 12 years but not exceeding 25 years.

Long-Term Customer: A person who has been granted long-term access and includes a person who has been allocated central sector generation that is electricity supply from a generating station owned or controlled by the Central Government.


Medium-Term Customer: A person who has been granted medium-term open access.

Medium-Term Open Access: The right to use the inter- State transmission system for a period exceeding 3 months but not exceeding 3 years.

Multi –Part tariff: Tariff with at least two components of tariff, viz. capacity charge and energy charge.


National Electricity Plan: Means the National Electricity Plan notified under sub-section (4) of section 3 of Electricity Act 2003.

National Grid: National Grid means the entire inter-connected electric power network of the country.

National Load Despatch Centre (NLDC): Means the Centre established under subsection (1) of section 26 of Electricity Act 2003.

Net Drawal Schedule: The drawal schedule of a beneficiary after deducting the apportioned transmission losses (estimated).

Normative Availability: Means annual Availability equal to 85%.


Open Access: Means the non-discriminatory provision for the use of transmission lines or distribution system or associated facilities with such lines or system by any licensee or consumer or a person engaged in generation in accordance with the regulations specified by the Appropriate Commission.

Operation Coordination Sub- Committee (OCC): A sub-committee of RPC with members from all the regional entities which decides the operational aspects of the Regional Grid.

Overhead Line: Means an electric line which is placed above the ground and in the open air but does not include live rails of a traction system.


Pool Account: Regional account for (i) payments regarding unscheduled-interchanges (UI account) or (ii) reactive energy exchanges (reactive energy account) or (iii) congestion charge or (iv) renewable regulatory charge, as the case may be.

Power Exchange: Means the power exchanges which have been granted registration in accordance with CERC Power Market Regulations, 2010 and as amended from time to time.

Power System: Means all aspects of generation, transmission, distribution and supply of electricity and includes one or more of the following, namely:- (a) generating stations; (b) transmission or main transmission lines; (c) sub-stations; (d) tie-lines; (e) load despatch activities; (f) mains or distribution mains; (g) electric supply-lines; (h) overhead lines; (i) service lines; (j) works.

POWERGRID: Power Grid Corporation of India Limited which has been notified as CTU.

Primary Energy: The quantum of energy generation up to Design Energy on an annual basis.about the electricity system is made available to the concerned Load Despatch Centre.


Regional Energy Account (REA): A regional energy account, for the billing and settlement of ‘Capacity Charge’, ‘Energy Charge’, ‘UI Charge’ and ‘Reactive Charge’.

Regional Entity: Means such persons who are in RLDC control area and whose metering and energy accounting is done at the regional level.

Regional Grid: The entire synchronously connected electric power network of the concerned Region.

Regional Load Despatch Centre (RLDC): Means the Centre established under sub-section (1) of Section 27 of Electricity Act 2003.

Regional Power Committee (RPC): Means a Committee established by resolution by the Central Government for a specific region for facilitating the integrated operation of the power systems in that region.


SEB: The State Electricity Board including the State Electricity Department.

Secondary Energy: The energy generation during the year over and above the Design Energy.

Sent Out Capacity: MW generation measured at generation terminals.

SERC: State Electricity Regulatory Commission.

Service-line: Means any electric supply-line through which electricity is, or is intended to be, supplied -(a) to a single consumer either from a distributing main or immediately from the Distribution Licensee's premises; or (b) from a distributing main to a group of consumers on the same premises or on contiguous premises supplied from the same point of the distributing main.

Share Percentage: share of a beneficiary in an ISGS: either notified by Government of India or agreed through contracts and implemented through long term access.

Short-term Open Access: Open Access for a period up to one (1) month at one time.

Spinning Reserve: Part loaded generating capacity with some reserve margin that is synchronized to the system and is ready to provide increased generation at short notice pursuant to despatch instruction or instantaneously in response to a frequency drop.

Stand Alone System: Means the electricity system set-up to generate power and distribute electricity in a specified area without connection to the grid.

State Commission: Means the State Electricity Regulatory Commission constituted under sub-section (1) of section 82 of Electricity Act 2003 and includes a Joint Commission constituted under sub-section (1) of section 83 of Electricity Act 2003.

State Load Despatch Centre (SLDC): Means the Centre established under subsection (1) of Section 31 of Electricity Act 2003.

State Transmission: Means the Board or the Government Company specified as such by the Utility (STU) State Government under sub-section (1) of Section 39 of the Act.

Sub-Station: Means a station for transforming or converting electricity for the transmission or distribution thereof and includes transformers converters, switch-gears, capacitors, synchronous condensers, structures, cable and other appurtenant equipment and any buildings used for that purpose and the site thereof.


Time Block: Block of 15 minutes each for which Special Energy Meters record values of specified electrical parameters with first time block starting at 00.00 Hrs.

Total Transfer Capability (TTC): The amount of electric power that can be transferred reliably over the inter-control area transmission system under a given set of operating conditions considering the effect of occurrence of the worst credible contingency.

Trading: Means purchase of electricity for resale thereof and the expression "trade" shall be construed accordingly.

Transmission License: A License granted under Section 14 of Electricity Act 2003 to transmit electricity.

Transmission licensee: Means a licensee authorised to establish or operate transmission lines.

Transmission lines: Means all high pressure cables and overhead lines (not being an essential part of the distribution system of a licensee) transmitting electricity from a generating station to another generating station or a substation, together with any step-up and step-down transformers, switch-gear and other works necessary to and used for the control of such cables or overhead lines, and such buildings or part thereof as may be required to accommodate such transformers, switch-gear and other works.

Transmission Reliability Margin (TRM): The amount of margin kept in the total transfer capability necessary to ensure that the interconnected transmission network is secure under a reasonable range of uncertainties in system conditions.


Unscheduled Interchange (UI): In a time block for a generating station or a seller Means its total actual generation minus its total scheduled generation and for a beneficiary or buyer means its total actual drawal minus its total scheduled drawal.

Utility: Means the electric lines or electrical plant, and includes all lands, buildings, works and materials attached thereto belonging to any person acting as a generating company or licensee under the provisions of Electricity Act 2003.


Wheeling: Means the operation whereby the distribution system and associated facilities of a transmission licensee or distribution licensee, as the case may be, are used by another person for the conveyance of electricity on payment of charges to be determined under section 62 of Electricity Act 2003.

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