Power systems are the backbone of modern society, responsible for generating, transmitting and distributing electricity to homes, industries and businesses. They include a complex network of components including power plants, transformers, transmission lines and distribution networks. Ensuring reliability and efficiency in power systems is crucial, especially with the growing integration of renewable energy sources like solar and wind. Advances in smart grid technology, real-time monitoring and automation are transforming traditional power systems, enabling better demand response, fault detection and energy management. Key challenges include maintaining grid stability, managing peak loads and addressing cybersecurity threats. Understanding the details of power systems is essential for developing sustainable and reliable energy solutions to meet the increasing global demand for electricity while minimizing environmental impact. This book provides comprehensive insights into the field of power systems. Also included in this book is a detailed explanation of the various concepts and applications of state estimation methods, including Kalman filters and particle filters, providing practical insights into their implementation. This book will provide comprehensive knowledge to the readers.