Haryana BSEH Senior Secondary NSQF Power cheat sheet

Energy is measured in joules (J); power is the rate of energy transfer, 1 W = 1 J/s, and 1 kWh = 3.6 MJ.

Primary energy sources split into conventional (coal, lignite, natural gas, oil, large hydro, nuclear) and renewable (solar, wind, small hydro, biomass, biogas, geothermal, tidal).

India's electricity chain has four links: generation, transmission, distribution and consumption; transmission and distribution together are called the grid.

Commercial energy sources are bought and sold (coal, oil, gas, electricity); non-commercial sources include firewood, agricultural residue and animal dung.

Load factor = average load / maximum demand over the same period; a higher load factor means the plant capacity is used more evenly.

Diversity factor = sum of individual maximum demands / maximum demand on the system; it is always greater than or equal to 1.

Per-capita electricity consumption = total annual energy consumed (kWh) / population; it is a standard development indicator.

A unit of electricity in billing is 1 kWh, i.e. 1000 W used for one hour; a 100 W lamp burning 10 hours consumes 1 unit.

Thermal plant efficiency chain: boiler efficiency x turbine efficiency x generator efficiency; overall efficiency of a coal plant is typically 30-38%.

Rankine cycle is the working cycle of steam plants; reheating and regenerative feed heating raise cycle efficiency.

Hydro power output P = rho x g x Q x H x eta, where Q is discharge in m3/s, H is net head in m and eta is overall efficiency.

Wind power available in the air stream P = 0.5 x rho x A x v^3; power varies with the cube of wind speed, and Betz limit caps extraction at 16/27 (about 59.3%).

Solar PV output depends on irradiance and temperature; module efficiency falls as cell temperature rises, so ventilation of modules matters.

A solar cell is a p-n junction; the photoelectric effect generates electron-hole pairs, and the cell is characterised by open-circuit voltage, short-circuit current and fill factor.

Nuclear fission of U-235 releases about 200 MeV per nucleus; heavy water and light water reactors differ mainly in moderator and coolant.

Biomass and biogas plants use anaerobic digestion or combustion; biogas is mainly methane (50-70%) and carbon dioxide.

Plant capacity factor = actual energy generated / (rated capacity x hours in period); it differs from load factor, which concerns demand.

Transmission voltage levels in India: 66 kV, 110 kV, 132 kV, 220 kV, 400 kV, 765 kV AC, plus HVDC links such as +/-800 kV.

For the same power and power factor, raising voltage reduces current and therefore I^2R loss; line loss is inversely proportional to the square of voltage.

Standard supply frequencies and voltages: 50 Hz in India; LT distribution at 400 V three-phase, 230 V single-phase.

A transmission line is classified short (below 80 km), medium (80-250 km) and long (above 250 km); nominal pi and T models suit medium lines.

Surge impedance Zc = sqrt(L/C); surge impedance loading SIL = V^2 / Zc gives the natural power limit of a line.

Skin effect pushes AC current to the conductor surface and raises effective resistance; it increases with frequency and conductor diameter.

Corona loss increases with voltage and is reduced by using bundled conductors and larger conductor diameter.

Distribution feeders are radial, ring-main or interconnected; a radial feeder has no back-feed, so a fault interrupts all downstream consumers.

Ferranti effect raises receiving-end voltage above sending-end voltage on a lightly loaded long line, especially with capacitive charging current.

Transformer EMF equation: E = 4.44 x f x N x Phi_max; voltage per turn is constant on both windings of an ideal transformer.

Transformer losses: copper loss varies as the square of load current, core loss is nearly constant; maximum efficiency occurs when copper loss equals core loss.

Synchronous machine speed n = 120 f / P, where P is the number of poles; a 4-pole machine at 50 Hz runs at 1500 rpm.

Slip of an induction motor s = (Ns - N)/Ns; rotor frequency equals s x supply frequency, and rotor EMF at standstill is the blocked-rotor value.

A three-phase induction motor is self-starting because the rotating field induces rotor currents; a single-phase induction motor needs an auxiliary or capacitor winding.

Torque of a DC motor is proportional to flux and armature current; a shunt motor is a constant-speed machine, a series motor gives high starting torque.

A DC generator is commutated to produce DC at the terminals; the commutator also acts as a mechanical rectifier.

Motor starters (DOL, star-delta, autotransformer, soft starter) limit starting current; star-delta reduces starting current to one-third of the DOL value.

Alternator excitation controls reactive power and terminal voltage; over-excitation supplies lagging reactive power to the grid.

A protection scheme must be selective, sensitive, fast and reliable; it must also be stable against faults outside its zone.

A relay is defined by its pick-up value (minimum operating current) and its time-current characteristic; an IDMT relay trips faster at higher fault current.

Current transformer (CT) and potential transformer (PT) step down current and voltage to relay-friendly levels; CT secondary is never open-circuited under load.

Distance relays measure impedance Z = V/I and are set in zones: zone 1 about 80% of the line, zone 2 about 120%, zone 3 for backup.

Differential protection compares currents at both ends of a transformer or generator; it responds to internal faults and is immune to through-faults.

Circuit breakers are rated by breaking capacity in MVA or kA; an isolator must never be opened on load, only after the breaker has cleared.

Earthing types: TT, TN-S, TN-C, TN-C-S and IT; protective earth limits touch voltage and lets the protective device operate.

Earth resistance is measured by the fall-of-potential method; a low earth resistance (commonly 1-5 ohm for substations) is required for effective fault clearance.

First aid for electric shock: switch off the supply, use an insulated object to separate the victim, then start CPR if breathing has stopped.

Energy audit types: preliminary (walk-through) audit, detailed audit and targeted audit; a detailed audit uses metered data and cost-benefit analysis.

Energy conservation means using less energy for the same service; energy efficiency means delivering the same output with less input energy.

Energy audit instruments include power analyser, lux meter, anemometer, flue gas analyser, thermal imager and ultrasonic leak detector.

Payback period = initial investment / annual energy cost saving; a shorter payback means a faster-returning measure.

Life-cycle cost adds capital, operating, maintenance and disposal costs over the equipment life; it captures savings that simple payback misses.

Specific energy consumption = energy input / production output; tracking it over time reveals efficiency drift in a plant.

Power factor improvement capacitors reduce line current and kVA demand; kVAR required = P x (tan phi1 - tan phi2).

Lighting efficiency is measured in lumens per watt; LED lamps commonly deliver 80-150 lm/W against about 15 lm/W for incandescent lamps.

The Energy Conservation Act, 2001 created the Bureau of Energy Efficiency (BEE); BEE star labels rate appliances on a 1-5 star scale.

The Electricity Act, 2003 unbundled generation, transmission and distribution and enabled open access and trading of electricity.

CERC regulates inter-state transmission and tariffs; SERCs regulate intra-state distribution tariffs and retail supply.

A distribution franchisee operates a utility's network in a defined area under a franchise agreement, earning a return on collection and loss reduction.

Energy service company (ESCO) model: the ESCO invests in efficiency measures and is paid from the measured savings, often under a performance contract.

A net-metering consumer with rooftop solar exports surplus units and gets credit against imported units at the retail tariff.

Tariff components usually include fixed or demand charges, energy charges, power factor penalty or incentive, and electricity duty.

Aggregate technical and commercial (AT&C) loss = (energy input - energy billed and collected) / energy input; it combines technical loss and collection loss.

A business plan for a power venture states the market, technical design, capital cost, revenue model, payback and regulatory approvals needed.

Small hydro, rooftop solar and biomass gasifier projects are common rural entrepreneurship options supported by state renewable energy policies.

A resume for a technical role lists contact details, skills, qualifications, projects and references, and is usually one to two pages.

A cover letter follows a three-part structure: why you are writing, what you offer, and a request for an interview.

The 5S workplace method: sort, set in order, shine, standardise and sustain; it is a foundation of shop-floor discipline.

Personal protective equipment in electrical work includes insulated gloves, safety shoes, helmet, safety glasses and arc-rated clothing.

Permit-to-work systems require isolation, lockout-tagout, testing for dead and formal authorisation before work on electrical equipment.

Communication in a team follows sender, message, channel, receiver and feedback; feedback confirms that the message was understood.

A job interview answer to a technical question should state the concept, give a worked example and mention a safety or practical implication.

Record keeping and documentation (log books, inspection reports, test certificates) support traceability and legal compliance in utility work.

Entrepreneurial skills for technicians include costing a job, quoting, invoicing, customer service and basic bookkeeping.