Влияние толщины изоляции защищенных проводов высоковольтных ЛЭП на их пропускную способность по току
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Дата
2018
ORCID
DOI
10.20998/2074-272X.2018.2.07
Науковий ступінь
Рівень дисертації
Шифр та назва спеціальності
Рада захисту
Установа захисту
Науковий керівник
Члени комітету
Видавець
НТУ "ХПИ"
Анотація
Разработана методика определения оптимальной толщины полиэтиленовой сшитой и оксидной изоляции для обеспечения наименьшего теплового сопротивления теплопередаче защищенных и неизолированных проводов. Обоснована применимость разработанной методики для оптимизации толщины изоляции защищенных проводов напряжением 20 кВ. Показана возможность повышения пропускной способности по току защищенных проводов на 20 % по сравнению с неизолированными проводами за счет оптимизации толщины их изоляции. Установлено, что внутренний перепад температуры в сшитой полиэтиленовой изоляции на порядок меньше в сравнении с оксидной изоляции при одинаковых значениях тангенса угла диэлектрических потерь.
The main direction of technical policy in the design, construction and technical re-equipment of transmission lines is the modernization of electrical networks and increase their energy efficiency in order to increase the throughput and reliability. Existing calculation methods do not take into account the influence of insulation thickness on the long-term current load of the wires according to the values of the maximum permissible working temperature of the conductors. The investigation of the influence of insulation thickness of the protected wires of high-voltage electric transmission lineson their current carrying capacity. The long operating temperature of the wire when the rated load current flows is determined based on the heat balance equation. A method has been developed for determining the optimum thickness of polyethylene cross linked and oxide insulation to provide the lowest thermal resistance to the heat transfer of protected wires, the use of which allows increasing the current carrying capacity by 20 % compared to bare wires. It is shown that the internal temperature drop in cross linked polyethylene insulation is an order of magnitude smaller in comparison with the oxide insulation at identical values of the dielectric loss tangent. The calculations take into account the presence on the surface of a non-insulated aluminum conductor of a natural dense film based on aluminum oxide, which protects it from further contact with air. The capacitance of a single phase conductor with insulation is determined on the basis of the calculation of the electric field in a piecewise homogeneous medium by the method of secondary sources.
The main direction of technical policy in the design, construction and technical re-equipment of transmission lines is the modernization of electrical networks and increase their energy efficiency in order to increase the throughput and reliability. Existing calculation methods do not take into account the influence of insulation thickness on the long-term current load of the wires according to the values of the maximum permissible working temperature of the conductors. The investigation of the influence of insulation thickness of the protected wires of high-voltage electric transmission lineson their current carrying capacity. The long operating temperature of the wire when the rated load current flows is determined based on the heat balance equation. A method has been developed for determining the optimum thickness of polyethylene cross linked and oxide insulation to provide the lowest thermal resistance to the heat transfer of protected wires, the use of which allows increasing the current carrying capacity by 20 % compared to bare wires. It is shown that the internal temperature drop in cross linked polyethylene insulation is an order of magnitude smaller in comparison with the oxide insulation at identical values of the dielectric loss tangent. The calculations take into account the presence on the surface of a non-insulated aluminum conductor of a natural dense film based on aluminum oxide, which protects it from further contact with air. The capacitance of a single phase conductor with insulation is determined on the basis of the calculation of the electric field in a piecewise homogeneous medium by the method of secondary sources.
Опис
Ключові слова
неизолированные провода, сшитая полиэтиленовая изоляция, оксидная изоляция, тепловое сопротивление, тепловой баланс, эффективный коэффициент теплопередачи, bare conductor, oxide insulation, thermal resistance, optimal insulation thickness
Бібліографічний опис
Беспрозванных А. В. Влияние толщины изоляции защищенных проводов высоковольтных ЛЭП на их пропускную способность по току / А. В. Беспрозванных, В. М. Золотарев, Ю. А. Антонец // Електротехніка і Електромеханіка = Electrical engineering & Electromechanics. – 2018. – № 2. – С. 41-46.