This book is intented to serve as a textbook for B.E/B.Tech. degree students of Electrical Engineering. It will also serve as a text reference for the students of Diploma in Electrical Engineering. This text is also useful for candidate appearing in AMIE, GATE, UPSC Engineering Services and other comprehensive examinations. The practising engineers would also find this book valuable as a concise reference for basic principles and application in 'Electrical Power Systems'.