How to reduce the costs of a low power factor?

power factor

Power Factor

  • The low power factor is expensive and inefficient.
  • The low power factor also reduces the distribution capacity of your electrical system
  • increasing the current flow and causing voltage drops.
  • We describe about the power factor and explain how you can improve your power factor
  • To reduce electricity bills and improve the capacity of your electrical system.

What is the power factor?

  • To understand the power factor, visualize a horse pulling a railway car on a railway.
  • Because the rail ties are even, the horse must pull the wagon from the side of the track.
  • The horse is pulling the railway car at an angle with respect to the direction of travel of this.
  • The power required to move the car on the road is the working power (real).
  • The wagon will not move sideways; therefore, the horse’s lateral attraction is a wasted effort or a power (non-reactive) that does not work.
  • The pull angle of the horse is related to the power factor, which is defined as the ratio between real power (of work) and apparent power (total).
  • If the horse is driven closer to the center of the track, the lateral traction angle decreases and the real power approaches the value of the apparent power.

For example,

This indicates that only 70% of the current provided by the utility is used to produce useful work.

Cause of low power factor:

The low power factor is caused by inductive loads (such as transformers, electric motors and high intensity discharge lighting), which are an important part of the energy consumed in industrial complexes.

Unlike the restive charges that create heat when consuming kilowatts, the inductive loads require that the current creates a magnetic field, and the magnetic field produces the desired work. The total or apparent power required by an inductive device is a compound of the following:

  • Actual power (measured in kilowatts, kW)
  • Reactive power, the power that works caused by the magnetization current necessary to operate the device (measured in kilo wars, kVA)

The reactive power required by inductive loads increases the amount of apparent power (measured in kilovolts amperes, kVA) in your distribution system.

Why improve your power factor?

Some of the benefits of improving your power factor are the following:

  • Your utility bill will be smaller. The low power factor requires an increase in the generation and transmission capacity of the electrical network to handle the reactive power component caused by inductive loads. Utility companies usually charge a penalty fee to customers with power factors less than 0.95.

The capacity of your electrical system will increase. The uncorrected power factor will cause energy losses in your distribution system. You may experience voltage drops as the power losses increase.

How to correct the power factor

  • Minimize the operation of idle or low-load motors.
  • Avoid the operation of equipment above its rated voltage.
  • Replace standard motors as they consume more power than low power motors.
  • An engine must be operated near its rated capacity to realize the benefits of a high power factor design.
  • Install capacitors in your AC circuit to decrease the magnitude of the reactive power.
  • As shown in the following image, the reactive power (measured in kVA) caused by

The capacitors store kVA and release energy that opposes the reactive energy caused by the induct-or. This implies that the inductance and the capacitance react 180 ° with each other. The presence of both in the same circuit results in the transfer of continuous alternating energy between the capacitor and the induct-or, thus reducing the flow of current from the generator to the circuit.

The reactive power required by the load is 100 kVA, this is what it would demand from the public network, however, as we need to raise the power factor to 0.95, we will have to install a 67-kVAR capacitor, therefore the load will no longer it will have to take the reactive power from the network but from the capacitor bank with which the apparent power is reduced from 142 to 105 kVA, which results in a 26% reduction in the current. The power factor is improved to 0.95, see the following figure:

Power kVA triangle kva and kw

In the analogy of “Horse and railroad car”, this is equivalent to decreasing the angle that the horse is pulling the highway leading the horse closer to the center of the railway. Because the lateral traction is minimized, less total effort is required from the horse to do the same amount of work.

Conclusion

ARVI UPS can provide the assistance you may need to determine the optimum power correction factor and to properly locate and install the capacitors in your electrical distribution system.

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