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When the power factor is leading, the capacitive kVAr is more than the Inductive kVAr and this still has to be supplied by the source. As kVA is the vector sum of kW and kVAr, still for the given kW, you have to produce more kVA. Alternately, for the given kVA, you can only convert partially into useful work.
Secondary effects are voltage boost in the system, availability of stored energy to feed the fault in case of a fault, increase in the asymmetrical component of fault current, increasing thus the peak value of the fault current, etc.
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What are the disadvantages of leading power factor on generator supply system?
in case of leading power factor the air gap flux inside the alternator will increase which may cause over heating of the stator end coil and overhang portions.
Can we improve generator power factor for increasing active power?
The 0.8 Power Factor provided by generator manufacturers is not the load power factor, but it is the nominal power factor used to calculate the kW output of an engine to supply the power for a particular alternator kVA output. Alternators are therefore designed to supply their rated kVA at 0.8 lagging power factor.
Is it desirable to have leading power factor loads?
Obviously, it is always desirable to have leading power factor loads so that the power factor of system can be kept leading.Leading power factor reduce losses and increases the efficiency of the system.WhatIn a non-corrected (leading OR lagging system), the load uses true power, but the generator must supply apparent power. Apparent power may be greater than real power, but can never be less. They are *equal* with a purely resitive load, and this gives a power factor of exactly 1.0, and is neither leading NOR laggingThe extreme example of a lagging system would be a capacitor drawing 10 amps on a 240 volt supply. The generator must supply 10 x 240 = 2400 watts of power, but the capacitor will actually dissipate *none* of this. We have a system with ZERO percent efficiency. 100 x (0/2400 = 0)The other extreme is an electric radiator that is purely resitive with a 10 amp current drain. It would demand 2400 watts from the generator and absorb all of it, producing 2400 watts of heating. Efficiency is 100 percent.Your "leading" system, such as a motor, would demand, say 2800 watts from the generator to deliver only 2400 watts of useful output energy (assuming the motor's mechanism is 100% efficient). Your leading system would have an efficiency of 100 x (2400/2800) = 85.7%.ANY system that has a leading or lagging power factor (a value less than 1.0) is going to be less than 100% efficient.Inductive (leaing) loads such as motors and fluorescent lights will often have capacitors connected across them to apply a lagging correction equal to their leading power factor and to correct the system back to a PF = 1.0.
What are the advntage of the leading power factor?
A leading power factor means that the current is leading the voltage. That means that in the AC cycle (50 or 60 Hz) the current reaches its peak before the voltage. The amount of phase-lead can be up to 90 degrees which means one quarter cycle, or 5 milliseconds in a 50 Hz system.
What happens when lagging Power Factor changes to leading PF?
when lagging Power Factor changes to leading PF, then the voltage across the circuit in which capacitor bank is connected, is increased.
When synchronus generator is supplying active and reactive power it is operating at leading or lagging power factor?
A synchronous generator is operating at lagging power factor (positive P & Q) when it is supplying P & Q to the system. P & Q are positive which means that they are flowing away from the bus where the generator is connected (overexcited case). On the other hand, it is operating at leading power factor when it is supplying P and absorbing Q. The sign of Q is negative which means that it is flowing towards the generator bus (underexcited case).
What are the disadvantages of leading power factor on generator supply system?
in case of leading power factor the air gap flux inside the alternator will increase which may cause over heating of the stator end coil and overhang portions.
What affect does a leading power factor have on alternator generator excitation currents?
When a leading power factor load is applied, the voltage of the genset or genset bus rises, and the voltage regulation system reduces exciter power, reducing the strength of the magnetic field. If the field fails, the generator set may slip a pole, which results in potentially catastrophic alternator damage. pawan
What is the function of capacitor in an electric generator?
In an electric generator, the function of a capacitor is to provide reactive power and improve the power factor of the generator. When a generator is connected to a load, the load may have a combination of resistive, inductive, and capacitive components. Inductive loads can cause the power factor of the generator to decrease, resulting in lower efficiency and voltage regulation. By adding a capacitor in parallel with the generator, the reactive power generated by the capacitor can offset the reactive power of the inductive load, leading to improved power factor correction. This helps to enhance the efficiency of power transfer and stabilizes the voltage. The capacitor absorbs and supplies reactive power, reducing the strain on the generator and ensuring a steady and efficient supply of electrical energy.
Is it possible to transmit power with leading power factor?
The power factor depends on the properties of the load, and if any power factor correction is done it has to happen at the load, so that the current in the transmission lines is reduced. Correcting the power factor at the sending end fails to address the problem.
What is the power factor of AC generator when the reactive power is equal to zero?
Per factor is 1 when reactive power is zero.
What the negative and positive sign shows for power factor?
Applying a negative or positive sign to power factor is an obsolete method of describing whether it is 'leading' or 'lagging'. We no longer do this. These days, a 'leading power factor' indicates that the load is capacitive and the load current is leading the supply voltage, and a 'lagging power factor' indicates that the load is inductive, and the load current is lagging the supply voltage. Having said that, a 'negative' power factor is also the mathematical consequence of 'negative power' -i.e. the direction of power when it is fed from the load back to the supply (e.g. when the grid feeds energy into a generator, causing it to 'motor'). In this case, the power factor isn't really negative, but simply appears to be so.
Can we improve generator power factor for increasing active power?
The 0.8 Power Factor provided by generator manufacturers is not the load power factor, but it is the nominal power factor used to calculate the kW output of an engine to supply the power for a particular alternator kVA output. Alternators are therefore designed to supply their rated kVA at 0.8 lagging power factor.
What is meant by Generator P.f?
the cosine of the angle between voltage and current of generator is called power factor (pf) of generator.
Leading and lagging power factor?
The terms, 'leading' and 'lagging' refer to what the load current is doing, relative to the supply voltage (Phase difference) -never the other way around. If the current is leading the voltage, then the power factor is 'leading'; if the current is lagging the voltage, then the power factor is 'lagging'.
Can be the power factor become negative reading?
Yes, power factor can be negative. That is the case of a generator. Power factor is the cosine of the phase angle between voltage and current, and the cosine can be positive or negative.AnswerNo. Power factor can be 'leading' or 'lagging', but it cannot be 'negative' or 'positive'.
Is it desirable to have leading power factor loads?
Obviously, it is always desirable to have leading power factor loads so that the power factor of system can be kept leading.Leading power factor reduce losses and increases the efficiency of the system.WhatIn a non-corrected (leading OR lagging system), the load uses true power, but the generator must supply apparent power. Apparent power may be greater than real power, but can never be less. They are *equal* with a purely resitive load, and this gives a power factor of exactly 1.0, and is neither leading NOR laggingThe extreme example of a lagging system would be a capacitor drawing 10 amps on a 240 volt supply. The generator must supply 10 x 240 = 2400 watts of power, but the capacitor will actually dissipate *none* of this. We have a system with ZERO percent efficiency. 100 x (0/2400 = 0)The other extreme is an electric radiator that is purely resitive with a 10 amp current drain. It would demand 2400 watts from the generator and absorb all of it, producing 2400 watts of heating. Efficiency is 100 percent.Your "leading" system, such as a motor, would demand, say 2800 watts from the generator to deliver only 2400 watts of useful output energy (assuming the motor's mechanism is 100% efficient). Your leading system would have an efficiency of 100 x (2400/2800) = 85.7%.ANY system that has a leading or lagging power factor (a value less than 1.0) is going to be less than 100% efficient.Inductive (leaing) loads such as motors and fluorescent lights will often have capacitors connected across them to apply a lagging correction equal to their leading power factor and to correct the system back to a PF = 1.0.
