Which power factor is better leading or lagging?

When the load of the linear electrical network is capacitive in nature then it generates a leading power factor. As against when the load is of inductive nature then it results in lagging power factor. In the case of leading power factor, the phase angle of current is positive with respect to voltage.

What will happen if a synchronous generator operates with a lagging power factor leading power factor and unity power factor?

By convention, a synchronous generator operating with a lagging power factor is producing vars, while one operating with a leading power factor is consuming vars. The primary difference is that a generator will put out real power in addition to the reactive power by merely changing the field voltage.

Why synchronous motor runs at lagging power factor when it is under Excited?

Detailed Solution. Synchronous motor: V curves for synchronous motor gives the relation between armature current and DC field current. Lagging power factor: If field excitation is such that Eb < V the motor is said to be under excited and it has a lagging power factor.

Why generators are operate at lagging power factor?

Inductive loads such as electrical motors, which make up a large part of the load on the grid, draw lagging power. That is, the power factor is less than 1.0 (typically around 0.8), and the current waveform lags the voltage – the peak of the current occurs after the peak of voltage.

What is generator lagging?

Lagging of a generator is a common phenomenon, which indicates that the phase of current lags behind the phase of voltage, indicating that the circuit is inductive and the load of generator is the main type.

How do you excite a synchronous generator?

To excite the field winding of the rotor of the synchronous machine, direct current is required. Direct current is supplied to the rotor field of the small machine by a DC generator called Exciter. A small DC generator called Pilot Generator supplies the current to the Exciter.

How does synchronous motor improve power factor?

A Synchronous Motor can be made to operate at unity and leading power factor by just increasing its excitation voltage i.e. by increasing the field current. This advantage of Synchronous Motor is used to improve the power factor. Hence, Power Factor = CosƟ = Cos0 = 1.

Is a leading power factor bad?

Effects of Leading Power Factor The main harmful effect of the leading power factor is, it creates a high voltage in the circuit which can affect the load as well as the power supply circuit.

How can a synchronous generator be made to have a leading power factor?

Once the synchronous motor is synchronized, the field poles on the rotor are in line with the rotating magnetic poles of the stator. To increase the line voltage, the motor will supply ac magnetizing current to all “magnets” on the system to increase their magnetic flux. This is leading power factor.

Why does a synchronous generator need a lagging power factor?

Operating a synchronous generator with a lagging power factor does not require additional power from the prime mover. It does, however, reduce the amount of real power that the generator can produce by increasing the stator winding current.

What is the function of synchronous generator?

Synchronous generator converts mechanical power to ac electric power. The source of mechanical power, the prime mover, may be a diesel engine, a steam turbine, a water turbine, or any similar device. For high-speed machines, the prime movers are usually steam turbines employing fossil or nuclear energy resources.

What happens when a generator power factor is low?

In many cases, a generator operating with a lagging power factor can have its control settings changed or type so that it will put out more KW and less vars. The additional kW output of the machine can be utilized to offset power consumption or sold back to the power provider for revenue.

When a synchronous motor runs at unity power factor?

When a synchronous motor runs at unity power factor, then no reactive power is drawn by the motor. Is it right or not? Complex power input of motor is given by . At unity power factor, current is completely is in phase with and .