PSF Power Supply Factor

Power Supply Factor (PSF) is a term used to describe the quality and efficiency of an electrical power supply system. It represents the ratio between the real power (in watts) and the apparent power (in volt-amperes) drawn by an electrical load from the power source. PSF is a dimensionless quantity expressed as a decimal or a percentage.

To understand PSF, let's first define real power (P) and apparent power (S):

1. Real Power (P): Real power is the actual power consumed by an electrical load to perform useful work. It is measured in watts (W) and represents the power that is converted into a useful form, such as mechanical work, light, heat, etc. Real power is responsible for performing tasks and producing useful outputs.
2. Apparent Power (S): Apparent power is the product of the voltage (V) and current (I) drawn by an electrical load. It is measured in volt-amperes (VA) and represents the total power supplied to the load, considering both the useful power and reactive power. Reactive power is associated with reactive components in the load, such as inductors and capacitors, which store and release energy in the form of magnetic and electric fields.

Now, let's calculate the Power Supply Factor (PSF):

PSF = P / S

A PSF value closer to 1 indicates a more efficient power supply, where the real power (P) is closer to the apparent power (S). A PSF value of 1 means that the load is purely resistive, consuming all the power drawn from the source for useful work. In such cases, the power factor is said to be unity.

However, in practical electrical systems, the presence of reactive components causes a difference between real power and apparent power, leading to a lower PSF value. This difference is due to reactive power, which oscillates between the source and the load without being consumed for useful work. Reactive power causes additional losses in the power distribution system and reduces the overall efficiency.

To improve the PSF and overall power efficiency, power factor correction techniques are employed. These techniques involve the use of power factor correction capacitors, inductors, or active power factor correction devices. They help to compensate for the reactive power, bringing the power factor closer to unity, reducing losses, and improving the system's efficiency.

In summary, Power Supply Factor (PSF) is a measure of the efficiency of an electrical power supply system. A higher PSF value indicates a more efficient system, where real power is closer to apparent power. Power factor correction techniques are used to improve the PSF by compensating for reactive power and reducing losses in the system.