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5УДК 62
Rasulov F.
Azerbaijan State Oil and Industry University (Baku, Azerbaijan)
ACCIDENTS ON HIGH VOLTAGE POWER LINES
Аннотация: electric transmission lines differ according to the probability of accidents occurring in them according to the voltage class they belong to. Thus, the vast majority of accidents that occur in 10/6 kV power transmission lines are caused by leakages in transition insulators of line wires at transformer stations and accidental contact of tree branches with overhead lines. However, in 110kV and higher voltage lines, input isolators are already specially prepared and the insulation reserve is high. The probability of tree branches touching high voltage lines is very low considering the height of the poles. On the other hand, high-voltage lines usually belong to electric power transmission networks and transmit energy from one destination to another over long distances. The areas through which the power transmission lines from such networks pass are not densely populated areas, but are desert or forest-reserved areas. In those areas, since there are areas where birds protect their nests or gather in mass, there are often phase-to-ground or other phase-to-phase closures. As it can be seen, for the investigation of damage occurring in high-voltage lines, the characteristics of the electrical equipment connected to those lines and the investigation of the areas they pass through are extremely important.
Ключевые слова: towers, input isolators, mounting armatures, partial discharges, leakage
current.
Introduction: High voltage transmission lines are raised from the power station where the electricity is generated by step-up power transformers and transmit the energy to the destinations from the busbars located in their distribution structures via switching equipment. These structures continue up to the portal abutments of most substations at the destination points. In some cases, they transmit electric energy from the distribution structure of the node substations to other substations through the next high-voltage lines (Figure 1). Damages to said connection points and elements of the
lines for various reasons eventually result in the opening of the lines. For this, when talking about the reasons for the opening of those lines, the structures of the mentioned elements and the damages that may occur in them should be classified and classified as the reasons for the opening of the lines 1,2.
Fig.1. Structure of electrical energy transmission in distribution networks.
Practical studies: In order to study the openings in high-voltage power transmission lines, it is necessary to look at the measures taken in the direction of accidents and their prevention in existing networks. The first of these, as we mentioned above, is the fact that lines 3passing through non-residential areas cause short-circuiting as a result of birds gathering to build nests or sit on those line supports. To prevent them, it is necessary to install things of different structures and sizes that birds can't touch.
This structure can prevent their accumulation by being installed on the supports of the lines and their traverse. The practical implementation of this structure was carried out on the 110 kV 2nd Masalli overhead line. This line, passing through the Hirkan national reserve, was broke to short-circuited several times during the migration season of birds. As a result, there were certain interruptions in the supply of electricity to consumers. In 2019, were installed on supports in the part of that line that passes through the territory of the national reserve [5]. As a result, line breaks have been reduced to a minimum. Also, the breakings occurring outside the migratory season of birds have decreased significantly. The results of the inspections concluded that this was due to the fact that the surface of the insulators remained clean. Later, the same method was used in the 220kV 3rd and 6th Masalli overhead lines belonging to
Azerenergy. The use of this structure in the sections of high-voltage overhead lines passing through protected areas has practically proven itself to meet both the protection of nature's fauna and the requirement of minimum interruption in electricity supply and reliability from the quality indicators of the electric network. Keeping the surface of the insulators clean has resulted in the minimization of leakage currents and partial discharges in them, which has led to an increase in their service life and an economical boiler 4.
Another reason for openings in high-voltage power transmission lines is surface discharges in rain or humid weather as a result of frequent dusting of insulators of lines passing through desert areas. In order to prevent this, the weather conditions are predicted in advance and the lines are opened planning for technical inspection and cleaning. However, since the process requires manpower and time, it is not possible to implement it regularly. As a result, it is inevitable to open the lines due to contamination. The reason for this is that insulators are made of two widely used materials. So, since both porcelain and glass material are hydrophilic substances, they can attract water and create a water ring. As a result, the dust on the water forms a conductive mixture in the insulator. Under the influence of the electric field, the part of the water channel causes discharge, leakage and eventually short circuit. In the end, that insulator chain becomes useless as a whole. In order to prevent the aforementioned, the surface of the insulators should be covered with a hydrophobic substance, so that it filters water without keeping it on it. Silicon is an example of such materials. Silicone coated glass fiber insulators of different sizes are made according to the ready-packaged voltage using silicon coating 5.
Conclusion: The vast majority of openings in high-voltage power electric transmission lines are caused by damage to supports. The damages that occur in the supports depend on the areas they pass through, the terrain and the characteristics of the environment. The engineering inspection for the study of openings should be both seasonal in nature and check the dependence on different hours of the day. For this, there should be a journal in which openings in electric transmission lines are specially noted and a chronicle of openings should be made.
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