This project report proposes a design and construction of model of protection equipment for three-phase transmission line by voltage relay for protect. By protection equipment can protect the transmission line from over voltage and under voltage on the transmission line The objective of design and construction model of protection equipment for three-phase transmission line. The objective for construction model of protection equipment for three-phase transmission line. For understand power system protection principles. And understand using to protection equipment for three-phase transmission line correct. From experimentation model of protection equipment could protect over voltage and under voltage on the transmission line

This thesis presents the design and construction of an experiments of the power flow in the power systems. For the operating system of the power flow in the power systems. Comprise with the real power Reactive power Voltage in the power system. To guide the planning and operation of power systems. The results of the experiment to calculate the pressure at various points in the Power loss of system. As well as finding solutions to problems. Occurring in the system such as under voltage or short circuit in the system. This is the basic of stability analysis of power system operation and planning