Impact of Inaccurate Line Impedance Data on Distance Protection Performance in 220kV Overhead Lines. Study Case: Delayed Tripping Effects in Voltage Stability

Distance protection is the most commonly used protection method that protects the power transmission lines. The basic principle of distance protection is based on local voltage and voltage measurements, where the relay responds to the impedance between the relay terminals and the location of the on-line damage point. These protection in principle are devices that measure the impedances of the line they protect in real time and make comparison of those values with the parameter values with which they are parameterized then based on this measure operate. Hence, the accurate recognition of line parameters and the proper parameterization of remote protection ensures their selective action. In this paper, the assessment of the influence of line impedance on distance protection parameters is analyzed. Since the distance protection of the lines is based on the principle of impedance measurement, the differences in the action of the protections before and after their parameterization have been compared based on the measured parameters and we expect to have differences depending on the type of short circuit and the distance of breakdown. The comparison of the error in the operation of the distance protections due to the parameters and the correct parameterization of the distance protections, ensuring selective action and voltage stability in the case of short circuits in the system, has also been made.