The Electrical power industry is one of the fastest growing industries in the world. Nowadays, electricity consumers are very much concerned of the quality of the supply they receive, due to increased use of sophisticated equipment in their day-to-day activities. Nature of electrical power is such that it can neither be conveniently stored in quantity nor be subjected to quality assurance checks before it is used. As such, study on Power Quality issues in power systems has become one of the most important areas in Electrical Engineering. Among many power quality problems that prevail in power systems, Harmonic distortion continues to cause more and more problems in electrical installations due to proliferation of high power semi conductor devices and power electronics in industrial processes, and microelectronics processors in a wide range of equipment's. The book focuses on the investigation of all the major steady state electrical phenomena that disturb the power quality of a conventional power system. The book is useful to professionals studying in electrical power systems.