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Which of the following devices are used for power factor correction in power factor correction substation?
Capacitor banks
Synchronous condenser
Induction motor
Both (a) and (b)
Both (a) and (b)
Power factor correction is the process of compensating for reactive power (measured in VAR) in an electrical network to bring the power factor closer to unity. Both capacitor banks (static) and synchronous condensers (rotating) are effectively used for this purpose to minimize line losses and improve voltage regulation.
Power factor correction is the process of compensating for reactive power (measured in VAR) in an electrical network to bring the power factor closer to unity. Both capacitor banks (static) and synchronous condensers (rotating) are effectively used for this purpose to minimize line losses and improve voltage regulation.
QcompтАЛ=P(tan╧ХoldтАЛтИТtan╧ХnewтАЛ) тАФ Required reactive power for correction
pf=cos╧Х=SPтАЛ тАФ Definition of power factor
Capacitor banks provide leading reactive power to neutralize the lagging reactive power consumed by inductive loads. A synchronous condenser is an over-excited synchronous motor running at no load; by adjusting its excitation, it can inject or absorb reactive power into the grid, providing a variable source of leading VARs to improve system stability.
Capacitor banks are static and cost-effective for fixed compensation.
Synchronous condensers provide dynamic, stepless control of reactive power.
Induction motors consume lagging reactive power and degrade power factor.
Unity power factor reduces I2R losses in the transmission line.
Reduces transmission line losses
Increases available capacity of transformers and generators
Improves voltage regulation
Capacitors are sensitive to harmonic distortions
Synchronous condensers require maintenance due to moving parts
Industrial distribution systems
Transmission substations
Large manufacturing plants with heavy motor loads
| Feature | Capacitor Bank | Synchronous Condenser |
|---|---|---|
Device Type | Static | Dynamic/Rotating |
Induction motors are load devices that contribute to lagging power factor, hence they are not used for correction.
Synchronous condensers act as a source of reactive power only when over-excited.
D is correct тАФ Both capacitor banks and synchronous condensers are established methods for injecting leading reactive power to compensate for inductive loading.
Always remember that 'Synchronous Motor' at no-load acts as a variable capacitor, whereas 'Induction Motor' always consumes reactive power, lowering the power factor.