Haryana BSEH Senior Secondary NSQF Power key terms

The ratio of average load to maximum demand over a given period. A higher load factor means equipment is used more evenly and generation cost per unit falls.

The greatest load drawn by a consumer or system during a specified interval, usually measured over 15 or 30 minutes. It sets the capacity that supply equipment must be able to carry.

The total rated capacity of all appliances and equipment installed at a consumer's premises. It is used for billing categories and for estimating the consumer's likely maximum demand.

The ratio of the sum of individual maximum demands to the maximum demand of the whole system. It is always greater than one because consumers do not all peak at the same time.

A systematic inspection and analysis of energy flows in a building or plant to identify where energy is wasted and which measures would reduce consumption most cost-effectively.

The amount of energy used to produce one unit of output, such as kWh per tonne of product. It allows comparison of efficiency between plants, shifts, or periods.

The time needed for the savings from an efficiency measure to recover its initial cost. Simple payback ignores interest, but is widely used to rank energy-saving proposals quickly.

The total cost of an asset over its whole life, including purchase, installation, operation, maintenance, and disposal. It gives a fairer comparison than initial price alone.

The cosine of the angle between voltage and current in an AC circuit, equal to real power divided by apparent power. A low value increases current and losses for the same useful power.

The product of RMS voltage and RMS current in an AC circuit, measured in volt-amperes. It combines real power and reactive power and determines the rating of cables and transformers.

The power that oscillates between source and reactive elements such as inductors and capacitors without doing useful work, measured in volt-amperes reactive. It is needed to maintain magnetic fields in motors and transformers.

A group of capacitors connected to a supply to supply reactive power locally and so improve power factor. It reduces line current, losses, and demand charges.

A static device that transfers electrical energy between two circuits at different voltage levels through mutual induction, with no change in frequency. It is essential for efficient bulk power transfer.

The ratio of primary turns to secondary turns of a transformer. It fixes the ratio of primary to secondary voltage and, inversely, of secondary to primary current.

A transformer whose secondary voltage is higher than its primary voltage. It is used at generating stations to raise voltage for transmission and so reduce line current and losses.

The conductors, towers, insulators, and hardware that carry bulk electrical power at high voltage between generating stations and load centres. Higher voltage reduces current and resistive losses.

The circuit that delivers power from a distribution substation to consumers in a locality. Feeders operate at medium voltage and are tapped by service connections along their route.

A distribution arrangement in which feeders form a closed loop fed from one or more points. It allows a faulty section to be isolated while supply continues through the other path.

A faint violet glow and hissing caused by ionisation of air around high-voltage conductors where the surface voltage gradient is high. It wastes power and causes radio interference and ozone.

The tendency of alternating current to concentrate near the surface of a conductor, raising its effective resistance at high frequency. It is one reason stranded conductors are used.

The rise of receiving-end voltage above sending-end voltage on a long, lightly loaded transmission line, caused by the line's capacitive charging current. Reactors are used to control it.

A switching device that opens a circuit automatically under fault conditions and extinguishes the arc, then can be reclosed. It protects equipment from overload and short-circuit currents.

A device that senses abnormal current, voltage, or other quantities and sends a trip signal to a circuit breaker. It is the decision-making element of a protection scheme.

A protection scheme that operates when current exceeds a set value for a set time, covering overloads and short circuits. Time-grading ensures the breaker nearest the fault trips first.

Deliberate connection of exposed metalwork or a circuit point to earth so that fault current flows safely and touch voltage stays low. It protects people and enables protective devices to operate.

A device that trips when the difference between live and neutral currents indicates leakage to earth. It gives fast protection against electric shock and earth leakage.

A manually operated switch used to disconnect equipment from the supply for maintenance, with no load-breaking capability. It must be opened only after the circuit breaker has cleared the load.

An AC motor in which current is induced in the rotor by a rotating magnetic field, so the rotor turns slower than synchronous speed. It is rugged, cheap, and the workhorse of industry.

The speed of the rotating magnetic field in an AC machine, equal to 120 times frequency divided by number of poles. An induction motor always runs slightly below this value.

The difference between synchronous speed and actual rotor speed of an induction motor, usually expressed as a percentage of synchronous speed. Slip rises with load and is near zero at no load.

A structure that removes waste heat from circulating cooling water by evaporation and air flow. In a thermal plant it condenses turbine exhaust steam and maintains the vacuum that raises efficiency.

A closed vessel in which water is heated under pressure to produce steam for driving a turbine. Its efficiency depends on fuel combustion, heat transfer surface, and flue gas losses.

A generating station that burns coal, gas, or oil to raise steam that drives a turbine coupled to a generator. Its overall efficiency is limited by the Rankine cycle.

A semiconductor device that converts sunlight directly into direct current by the photovoltaic effect. Cells are connected in modules and arrays to give the required voltage and power.

A power electronic device that converts direct current into alternating current at the required voltage and frequency. Grid-tied inverters also synchronise with the grid and provide safety disconnection.

The process of matching a generator's voltage, frequency, and phase sequence to the grid before connecting it. Incorrect synchronisation causes large currents and mechanical stress.

Energy from sources that are naturally replenished within a short time, such as sunlight, wind, water, and biomass. Such sources produce little or no direct carbon emissions during operation.

Planned utility actions that influence how and when consumers use electricity, through pricing, incentives, or direct control, to flatten the load curve and defer capacity addition.

The schedule of charges a utility applies for supplying electricity, often combining fixed, energy, and demand components. Tariff design influences consumer behaviour and utility revenue.