The thesis describes the development of the device and the principle of detection of faults in overhead medium voltage lines. Detection is conducted without going into the dangerous area of overhead lines through the measurement of electric and magnetic fields with the help of electronic sensors. The thesis is composed of several chapters. The first part describes the failures which occur in the overhead lines and various types of grounding the neutral point of the transformer. The second part describes the electromagnetic situation under the conductors of an overhead line, which is essential for the identification of the state of the network and fault detection. We describe the situation during normal operation, the short-circuit and earth fault.
The following is a brief description of the device and the principle of testing and calibration systems. Testing is divided into two parts: testing in a simulated environment and testing in a real environment. The thesis presents the development of devices for measuring defects in MV overhead lines. The main goal in the development of the device is the contactless detection of a fault (detection based solely on the measurement of electric and magnetic field strengths). The section describes situations (failures), and behavior (voltage, current) in normal and abnormal (fault) conditions. Understanding of these things is necessary to determine the algorithms and calculations, which will properly process the data and send necessary information to the user. To confirm the theoretical calculations and repeatability of results, thesis includes a description of the manufacturing of test devices and accessories, which were used during the development of the device and are also the basis for further factory testing devices before delivery to the final users.
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