Power quality enhancem ent by means of shunt compensators based on the conservative power theory

Passive filters are widely used in electrical system for power quality improvements. Their first installations date from 1940s and their advantages make them an attractive and standard solution. However, passive filters have their filtering characteristics deteriorated due to parameter variation, caused by aging and temperature. Additionally, a capacitor bank for power factor correction is designed for specific loads and may not supply the right amount of reactive power when loads keep being added or changed. A solution to overcome such undesired effects is presented in this paper. There are two shunt compensators, with design and control based on the Conservative Power Theory. They are employed as supporting a tuned passive filter plus a capacitor bank. They contribute towards a better passive filter performance with reduced processed power. The addition of those shunt compensators would be cost-effective for weak grid conditions and smart grid advanced energy management control. A case study is presented in order to prove the compensators efficacy and the power quality improvement.