Simply put, power quality is a measure of an ideal power supply system. In general, power quality as a concept is no different from the notion of quality for goods or services of all kinds. But while quality is a general concept that includes subjective attributes like personal likeability, taste or gut-feel, power quality is an objective, measurable and clear metric that tells us about the state of the power being supplied.
Broadly, PQ may be defined as a provision of voltages and a system design so that the user of electric power can utilise electric energy from the distribution system successfully, without interference on interruption.
Figure: Disrupted three phase voltage