Distortion of location pulses in high-frequency paths of overhead power lines

Abstract

The work is devoted to the features of propagation of electromagnetic signals (20–1000 kHz) along multi-wire overhead transmission lines. For monitoring the status of overhead power lines, a location method can be used. For connection to power lines, the connection equipment is used, which forms the high-frequency path of the power line, which has a limited frequency bandwidth. To select the optimal signals of location probing, it is necessary to investigate the impact of high-frequency path on the pulsed signals. This paper investigates the distortion of pulsed location signals in high-frequency paths. The influence of elements of the high-frequency path is studied using a simulation model of the high-frequency path of an overhead transmission line developed in the PSCAD software environment with subsequent experimental verification. Elements of high-frequency path of the developed simulation model are described. The influence of duration of the probe pulses on the shape and spectrum of the reflected signals is analyzed. It was established that during the passage of microsecond pulses, their differentiation occurs, the reflected signal is a combination of responses from the rising and falling edges of the probe pulse. With this in mind, criteria are proposed for optimizing the duration of the location pulses. During formation of ice deposits on the overhead lines wires, additional distortion of the pulse signals’ shape occurs. Using the experimental data, the distortions of the reflected pulsed signals and their spectra are analyzed as ice deposits grow on the wires of overhead power lines. The established patterns of pulse shape distortion and the developed criteria for optimizing the pulse duration are used for location probing of overhead power lines to control ice deposits on the wires and to detect damage.