Distance Protection Algorithm for Three Terminal Transmission Lines Using Local Measurement

If there is a short circuit fault in the transmission line, it is necessary to quickly and accurately arrange it in order to restore the faulty part, minimize the power interruption time of the transmission path, and restore the power supply as soon as possible. Therefore, the development of a robust and accurate fault position identification technique under various fault conditions is a very important research field. In some low power density areas, utilities use tapped lines to connect to existing transmission lines due to economic advantages.

Schematic diagram of long distance power transmission. C = consumption, D = step down transformer, G = generator, I = current in the conductor, Pe = power to the end of the transmission line, Pt = power to the transmission line, Pw = power loss of the transmission line, R = wire , V = the voltage at the start of the transmission line, U = boost transformer AC voltage can be increased or decreased by the transformer so that the electrical energy is distributed as an alternating current. This allows the power to be efficiently transmitted at high voltage through the power line, which reduces the energy lost as heat due to the resistance of the wire and is converted to a lower, safer voltage for use . Using higher voltages will greatly improve power transmission efficiency. The power loss of the wire is the product of the square of the current (I) and the resistance (R) of the wire as expressed by the following equation.

High voltage transmission is the transmission of a large amount of electric energy from a power plant to a substation. This refers to the local wiring between the high-voltage substation and the customer as power distribution. When the transmission lines are connected to each other, it becomes a high voltage grid. Although the transmission line mainly uses three-phase alternating current (AC), single-phase alternating current may be used in rail electrification system. High voltage direct current (HVDC) technology is used only for very long distance, submarine cable. To reduce energy loss in long distance transmission, power is transmitted at high voltage. Electricity is usually transmitted via overhead power transmission lines. Underground power transmission has very high cost and greater operational constraints. The main problem in power distribution is that electric energy can not be stored, so electric energy is generated as necessary.

Transmission lines are the medium that transfers electrical energy over long distances from one location to another to reduce power and make it economical. Voltage, current, power, power factor are the points that need to be taken into consideration at the transmitting side and the receiving side. In general, overhead transmission lines are used in Malaysia because cost and maintenance can be easily handled. It is well known that power transmission lines generate strong electric and magnetic fields under the tower. Based on this, the project emphasizes the voltage of 275 kV and uses finite element method (FEM) to model the transmission line. The simulation result of the transmission line model analyzes the electric field and the magnetic field under the transmission line tower.