One of the major concerns in electricity industry today is power
quality. Restructuring of power systems and with shifting trend towards
distributed and dispersed generation, the issue of power quality is
going to take newer dimensions. In developing countries like India,
where the variation of power frequency and many such other determinants
of power quality are themselves a serious question, it is very vital to
take positive steps in this direction. It becomes especially important
with the introduction of advanced and complicated devices, whose
performance is very sensitive to the quality of power supply. With the
deregulation of the electricity market, providing quality power has
become an important concern for both power suppliers and customers.
Efforts have been made to improve the power quality using passive
filters, active power filters, hybrid filters and the new concept of
custom power devices.