The content of the book focuses on all aspects of electricity that most power engineers engage in during their professional careers. Most power engineers work in the distribution and use of electricity in cities, factories and refineries, commercial buildings and institutions, electric trains, loading ports, cruise ships, etc. Their daily work involves distributing energy to load equipment such as motors and industrial heaters through step-down transformers and cables. System protection is an important part of their operation, which requires switches, relays and fuses. Some engineers working in thermal power plants are interconnected with generators.