TSGENCO AE key terms

The ratio of average load over a period to the maximum demand during that period. A high value means plant capacity is used steadily rather than sitting idle most of the day.

The ratio of the sum of individual maximum demands of consumers to the maximum demand on the station. It is always greater than one because consumers peak at different times.

The tendency of alternating current to concentrate near the surface of a conductor, raising effective resistance as frequency increases. It is negligible at DC and low frequencies but significant in thick conductors at power frequencies.

The rise of receiving-end voltage above sending-end voltage on a long lightly loaded transmission line, caused by the line's shunt capacitance charging current flowing through its series inductance.

The load at which a lossless line's reactive power generation exactly balances its reactive power absorption, numerically equal to the square of receiving voltage divided by surge impedance.

Ionisation of air around a high-voltage conductor when the surface voltage gradient exceeds the breakdown strength of air, producing hissing, ozone smell, power loss and radio interference.

A graphical stability test in which the accelerating area between the power-angle curve and the mechanical input must be matched by a decelerating area for the generator to remain in synchronism after a disturbance.

The largest rotor angle at which a fault may be cleared while the generator still regains synchronism. Clearing faster than the corresponding critical clearing time preserves stability.

The fractional difference between synchronous speed and actual rotor speed of an induction machine, expressed as s = (Ns - Nr)/Ns. It is one at standstill and near zero at no load.

The curve relating electromagnetic torque of an induction motor to slip, showing a stable low-slip region, a maximum torque at the breakdown slip, and a high-slip starting region.

The speed of the rotating magnetic field, given by 120 times frequency divided by number of poles. It is the speed at which a synchronous machine runs in steady state.

The rise in secondary terminal voltage when full load is removed at a given power factor, expressed as a percentage of rated voltage. It indicates how well a transformer or alternator holds its voltage.

Connecting transformers to share a load, requiring matching polarity, voltage ratio, per-unit impedance and vector group. Mismatched impedance causes unequal load sharing and circulating currents.

The process in a DC machine by which the direction of current in a coil reverses as it passes the brush axis. Poor commutation causes sparking at the brushes and limits machine output.

The distortion of the main field flux by the magnetic field set up by armature current. It shifts the magnetic neutral axis and affects voltage regulation and commutation.

The fraction of each switching period during which a power semiconductor device conducts. In a buck converter the output voltage equals input voltage multiplied by duty cycle.

A static circuit that converts fixed DC input voltage into a variable DC output voltage by rapidly switching a semiconductor device on and off, controlled through the duty cycle.

A switching technique that synthesises a variable output voltage by varying the width of fixed-frequency pulses, widely used in inverters to control voltage and reduce low-order harmonics.

The presence of voltage or current components at integer multiples of the fundamental frequency, caused by non-linear loads and power electronic converters. Total harmonic distortion quantifies its severity.

Turn-off of a thyristor in a naturally commutated converter that relies on the AC supply voltage reversing to reduce the device current to zero, unlike forced commutation in DC circuits.

A current or voltage transformer that scales high line quantities down to safe measurable values for meters and relays while isolating the instrument from the high-voltage circuit.

A voltage transformer connected in parallel with the circuit whose secondary provides a standard low voltage proportional to the primary voltage for measurement and protection relays.

The total impedance of the secondary circuit, including relays, meters and leads, that a current transformer must drive at rated current. Excessive burden causes ratio and phase errors.

A four-arm resistive network used to measure an unknown resistance by balancing the bridge so that no current flows through the galvanometer connected across its centre.

The ideal thermodynamic cycle for steam power plants, consisting of isentropic pumping, constant-pressure heat addition in the boiler, isentropic expansion in the turbine and constant-pressure heat rejection in the condenser.

A steam cycle in which steam is expanded partway in the turbine, returned to the boiler for reheating at constant pressure, then expanded further, raising efficiency and limiting blade moisture.

Bleeding part of the steam from turbine stages to heat boiler feedwater, raising the cycle's mean temperature of heat addition and thereby improving thermal efficiency.

The sub-atmospheric pressure maintained in a steam condenser by removing air and cooling the exhaust steam, which lowers turbine exhaust pressure and increases work output.

A dimensionless index giving the speed at which a geometrically similar turbine would run while developing unit power under unit head. It determines whether a Pelton, Francis or Kaplan type suits a site.

Formation and collapse of vapour bubbles in a liquid where local pressure falls below vapour pressure, causing noise, loss of efficiency and pitting damage to pump and turbine surfaces.

The absolute pressure margin above vapour pressure available at a pump suction, expressed in metres of liquid. Insufficient NPSH leads to cavitation in the pump.

An abrupt rise in water surface when flow changes from supercritical to subcritical, dissipating large amounts of energy. It is deliberately created below spillways to protect structures.

The maximum pressure a soil mass can carry at the base of a foundation without shear failure or excessive settlement. It governs footing size and is found from field tests or theory.

Loss of shear strength in saturated loose sands when earthquake shaking raises pore water pressure until effective stress approaches zero, causing foundations to sink or float.

A structural design philosophy that checks separate collapse and serviceability requirements using partial safety factors on loads and material strengths instead of a single global factor.

A question type where the candidate decides whether the given statements alone are enough to answer a question, without actually computing the final value.

Puzzles that present family relationships through coded statements or a chain of relations, requiring the candidate to deduce how two named persons are related.

A large multi-stage lift irrigation scheme on the Godavari in Telangana, drawing water at Medigadda and lifting it through pump houses and reservoirs to serve command areas across several districts.

The long-running disagreement among riparian states over sharing Godavari waters, addressed through tribunal awards and inter-state agreements that shape Telangana's irrigation planning.