Transmission lines and sub-stations play an essential role in the electrical power systems and exercise a vital influence on the reliability of services. Creating an excellent design with state-of-the-art construction is crucial as long as transmission lines are in continuous operation. That should promote easy maintenance with the least possible level of interruptions. They call for a high degree of flexibility to deal appropriately with current control systems, available space and limited downtime. Learners will explore the routine testing, constructional features, and maintenance of the transmission lines.