Energy Transmission Lines

These are the lines that enable the electricity, which is generated in a controlled and planned manner at a power plant, to be transmitted from power plants to distribution lines. These systems allow for the power to be transmitted from power plants to transformer stations close to power consumption zones and from transformer stations to end users. While installing power lines, factors such as cost, route of the transmission line, geography, terrain conditions and security position of the line are taken into consideration. It is of great importance to securely install power lines and to transmit power with minimum loss.

Power transmission lines are divided into two groups, namely high and low voltage. High voltage lines are usually installed between power plants and  premises. On the other hand, low voltage lines are used for power distribution within the urban area. They are named according to the voltage of the energy they transmit. They are sized depending on the energy load and voltage. Today, long energy transmission lines are installed overhead in open fields and underground in settlement areas. Even though underground energy transmission lines are much more costly than overhead lines since they require high insulation, they are more opted for in terms of safety and visually. An overhead energy transmission line consists of a conducting cable of copper or aluminum, a pylon, and a non-conductive isolator that connects the pylon to the conductor. In more technical terms, lines between power plants and the transformer stations are high voltage, lines between large transformer stations and small transformer stations are medium voltage and lines between small transformer stations and end users are low voltage. Energy transmission lines in Turkey are installed and operated by Türkiye Elektrik İletim A.Ş. (TEİAŞ).

Energy transmission lines are lines that are installed in line with the standards allowing the generated power to be transported to distant locations and that generally consist of poles with various construction structures, conductors, grounding equipment, hardware, and insulator equipment. From the electrical perspective, energy transmission lines are characterized by line parameters and length. As with all sinusoidal alternating current-operated conductors, energy transmission overhead lines also have ohmic resistance, inductance, and capacity coefficients, shortly called R-L-C line constants. The ohmic resistance of energy transmission lines is greater than the direct current resistance, which is due to the skin effect. On the other hand, self and mutual inductance of phase conductors occur due to the flux ring formed by currents flowing in from neighboring conductors. Since sinusodial alternating current is used, the term of inductive reactance, which is a function of power frequency, is employed instead of the term of inductance. The ohmic resistance of the line and its inductive reactance are considered  series and the characterization of the line is realized by impedance, which is the series sum of these two magnitudes.