Stable voltages and undistorted waveforms are two characteristics which are very desirable in power systems.
Grounding affects voltage stability, and more importantly, is critical to personal safety.
Harmonics are a mathematical model we use to analyze distorted waveforms. Harmonics are a mathematical model of the real world. Let's examine how these power supplies operate. There is a law in electrical engineering called Ohm's Law. This basic law states that when a voltage is applied across a resistance, current will flow.