 # Difference between Leading and Lagging Power Factor In electrical engineering and power systems, there are two different types of power factor: leading and lagging. Each type has a specific meaning and purpose in how they affect the overall system. Understanding the difference between these two power factors is important for anyone working with or designing electrical systems. We’ll take a closer look at what leading and lagging power factors are and explain how they’re used.

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## What is Leading Power Factor?

Power factor is a measure of the efficiency of an electrical system. It is defined as the ratio of the real power, or the power that is actually used by the system, to the apparent power, or the power that is supplied to the system. A high power factor indicates that a system is using power efficiently, while a low power factor indicates that a system is wasting power.

Leading power factor occurs when the current in an electrical system leads the voltage by a small amount. This can happen when inductive loads are present in the system. While leading power factor does not inherently cause problems, it can reduce the efficiency of the system and increase energy costs. Therefore, it is generally desirable to have a lagging power factor, where the current lags behind the voltage. However, in some cases it may be necessary to use leading power factor to improve the efficiency of an electrical system.

## What is Lagging Power Factor?

Lagging power factor is the phase angle difference between the current flowing through a circuit and the voltage applied to that circuit. The power factor of a circuit is the ratio of real power to apparent power, and is a measure of how efficiently the circuit uses electrical energy.

A lagging power factor occurs when the current leads the voltage, and is typically caused by inductive loads such as motors and transformers. A lagging power factor can be corrected by adding a capacitor to the circuit, which will shift the current closer to being in phase with the voltage. correcting a lagging power factor can improve the efficiency of a circuit and reduce energy costs.

## Difference between Leading and Lagging Power Factor

The power factor of an AC electrical power system is defined as the ratio of the real power flowing to the load over the apparent power in the circuit, and is a dimensionless number between 0 and 1 (fractional). Real power is the capacity of the circuit for performing work in a particular time. Apparent power is the product of the current flowing through the circuit and the voltage on the circuit. Due to energy stored in a magnetic field, or inductance, lagging power factors occur when the magnetic field is not in phase with the current flowing through it. The delay between current and voltage reduces the amount of active power, or wattage, that is available.

In an AC system, a leading power factor occurs when inductive loads are such that they create a leading magnetic field with respect to current. A perfect, or 1.0 power factor exists when all of the apparent power results in real power output. Power factors less than 1 require more current to achieve the same amount of usefulness as at a 1.0 power factor. The higher currents required result in higher electric losses in distribution equipment and consequently higher electric bills.