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When an alternator connected to the bus-bar is shut down the bus-bar voltage will
increased
none of these
decreased
remain unchanged
remain unchanged
Quick Summary: In a large power system, an infinite bus-bar is maintained at a constant voltage and frequency regardless of the power input or the number of alternators connected to it. Therefore, when a single alternator is removed or shut down, the bus-bar voltage remains essentially unchanged due to the compensating effect of the remaining parallel-connected generators.
In a large power system, an infinite bus-bar is maintained at a constant voltage and frequency regardless of the power input or the number of alternators connected to it. Therefore, when a single alternator is removed or shut down, the bus-bar voltage remains essentially unchanged due to the compensating effect of the remaining parallel-connected generators.
VbusтАЛтЙИconstant тАФ The definition of an infinite bus system.
PtotalтАЛ=тИСPiтАЛ тАФ Total real power is the sum of remaining active units.
The bus-bar is an 'infinite bus' with very low internal impedance. When one alternator is disconnected, the load previously supplied by that machine is automatically redistributed among the remaining synchronized alternators through the action of their automatic voltage regulators (AVR) and speed governors, which maintain the system equilibrium.
An infinite bus-bar has zero internal impedance and infinite capacity.
The voltage and frequency are governed by the aggregate system capacity, not an individual unit.
Automatic Voltage Regulators (AVR) ensure the terminal voltage remains stable during unit disconnection.
Removing one unit only alters the load sharing (power factor/excitation) of the remaining units.
High system reliability
Voltage stability for large-scale distribution
Complex synchronization requirements
Requires high-speed protection systems
Grid-connected thermal and hydro power plants
Industrial distribution substations
The term 'infinite' refers to the ability of the bus to maintain constant voltage and frequency independent of the load variation.
If the alternator were connected to a small, isolated system rather than a bus-bar, the voltage would decrease.
D is correct тАФ The bus-bar acts as an infinite source where voltage is maintained constant by the remaining parallel-connected generators.
Always verify if the question specifies 'infinite bus' or 'isolated load'; in exams, bus-bar refers to the grid which is essentially an infinite system.