Energy Savings Calculation in a System with Harmonics

Abstract

Saving energy in today’s environment is very important. Calculating the energy savings is also important to derive a cost and efficiency comparison of a system before and after a selected energy efficiency intervention. When a system is linear (resistive load) and sinusoidal, the current is always in phase with the voltage for single and multi phase systems. Calculating energy savings is relatively simple when two systems are compared with each other. This is well documented in the IPMVP guidelines for energy saving calculations. This is not true for a non-sinusoidal single phase or multiple phase system having some form of distortion. This paper proposes a method of calculating energy savings using the IEEE 1459 standard as a guideline. It is proposed that only the fundamental active power is used for energy saving calculations as the higher order active power harmonics do not contribute to energy savings in any significant way.