This book focuses on research work related to aspects of planning, design and operation of electrical power system that cover generation, transmission and substation. Studies reported in this book mostly involve simulation approaches validated by experimental results to highlight that modern power system requires proper planning and design in order to warrant balanced, reliable, secure and safe operation. This book contains 11 chapters which are divided into three broad areas: generation, transmission and distribution. The first part of this book presents introduction to renewable energy as an alternative energy solution which includes system design for grid-connected and off-grid system. The second part of this book elaborates the applications of FACT devices in transmission system to improve efficiency with renewable energy for enhancing overall performance. The final part covers research work related to distribution side of the power system. This part includes studies on load monitoring and application of distribution system technologies as well as its impact to system performance. This book is beneficial for students and engineers who wish to enhance their knowledge on power system area as well as for researchers who are interested to understand further topics in power system research.