Магнітне поле високовольтних кабельних ліній при двосторонньому заземленні екранів кабелів
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Дата
2019
Автори
ORCID
DOI
Науковий ступінь
кандидат технічних наук
Рівень дисертації
кандидатська дисертація
Шифр та назва спеціальності
05.09.05 – теоретична електротехніка
Рада захисту
Спеціалізована вчена рада Д 64.050.17
Установа захисту
Національний технічний університет "Харківський політехнічний інститут"
Науковий керівник
Розов Володимир Юрійович
Члени комітету
Кіпенський Андрій Володимирович
Михайлов Валерій Михайлович
Куліченко В'ячеслав Вікторович
Михайлов Валерій Михайлович
Куліченко В'ячеслав Вікторович
Видавець
Національний технічний університет "Харківський політехнічний інститут"
Анотація
Дисертація на здобуття наукового ступеня кандидата технічних наук (доктора філософії) за спеціальністю 05.09.05 – теоретична електротехніка. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2019.
Дисертація присвячена розвитку методів вирішення задачі фізико-математичного моделювання та розрахунку магнітного поля (МП) високовольтних трифазних кабельних ліній (КЛ), виконаних з одножильних кабелів, при двосторонньому заземленні їх екранів. Для високовольтної трифазної КЛ запропоновано фізико-математичну модель, що дозволяє виконувати розрахунок МП КЛ і струмів в екранах за будь-якої схеми прокладання кабелів. Отримано вирази для коефіцієнта екранування МП КЛ при прокладанні кабелів "у площині" і "у трикутник" та, з використанням перетворення Кларк, наближений компактний вираз при прокладанні кабелів "у площині", похибка якого не перевищує 5%. Теоретично обґрунтовано та експериментально підтверджено можливість 2-4-кратного підвищення коефіцієнта екранування МП КЛ при двосторонньому заземленні екранів кабелів шляхом охоплення кабелів КЛ феромагнітними осердями. Отримано вирази для розрахунку коефіцієнта екранування в залежності від параметрів феромагнітних осердь, параметрів кабелів і схеми їх прокладання. Виконано верифікацію запропонованої фізико-математичної моделі та розрахункових співвідношень шляхом чисельного моделювання та на основі експерименту. Розроблено методику розрахунку МП КЛ та діючих значень струмів в екранах при двосторонньому заземленні власних екранів кабелів.
Thesis for scientific degree of candidate of technical sciences (Ph.D.), specialty 05.09.05 – theoretical electrical engineering. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2019. The thesis is devoted to the advancement of methods of physico-mathematical simulation and calculation of the magnetic field created by the high-voltage three-phase cable lines consisting of single-core cables with two-point bonded cable shields. The current tendency of the development of city electric networks implies an increasingly widespread use of three-phase high-voltage cable lines performed by ingleconductor cables with cross-linked polyethylene insulation. However, the cable line magnetic field can exceed the reference level for the population (0.5 μT for living space and 10 μT for an urban area). Therefore, when designing cable lines it is mandatory to calculate accurately their magnetic field using existing regulation documents and analytical solutions based on known methods. At the same time, in the case of two-point bonding, the cable shields form closed loops in which longitudinal currents are induced. These currents create an additional magnetic field that substantially changes the initial cable line magnetic field, that must be taken into account. The problem of simulation of the magnetic field of the cable line with two-point bonded cable shields can be solved numerically. However, analytical methods are more affordable for cable line designers. Also, these methods produce results with a transparent physical interpretation. However, the analytical methods of solving these problems are insufficiently studied. This is due to the lack of theoretically based methods for determining the complex amplitude of currents in the shields of three-phase cable lines and the methods of magnetic field simulating at any arrangement of phase cables. In the thesis, the features of a three-phase cable line with two-point bonded shields as the source of the magnetic field are investigated. It is shown that correct methods of calculating the magnetic field of cable lines can be created only if the currents in cable shields, which are inductively connected with the currents in cable cores, are determined. The analysis of electromagnetic processes in a three-phase cable line with two-point bonded shields based on the method of complex amplitudes is carried out. A generalized physico-mathematical model of the magnetic field of cable lines is developed. It allows to calculate the electric currents induced in shields of cables and to determine the magnetic field distribution for the arbitrary arrangement of cables. The exact expression for the magnetic field shielding factor for the trefoil cable line with two-point bonded shields is obtained. Using the Clark transformation, a simplistic expression for the magnetic field shielding factor is received for the flat cable line with twopoint bonded shields. Its error is within 5%. The possibility of the magnetic field shielding factor 2-4 times increase by ferromagnetic cores installed on cables is justified theoretically and experimentally. In this case the shielding factor depends on parameters of ferromagnetic cores, parameters of cables and their arrangement. The respective expressions for the shielding factor are obtained for trefoil and flat cable lines. The verification of the proposed physico-mathematical model and analytical expressions is performed by numerical simulation and experimentally. Methodologies of the magnetic field and root-mean-square shield currents calculating for the cable line with two-point bonded cable shields are developed.
Thesis for scientific degree of candidate of technical sciences (Ph.D.), specialty 05.09.05 – theoretical electrical engineering. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2019. The thesis is devoted to the advancement of methods of physico-mathematical simulation and calculation of the magnetic field created by the high-voltage three-phase cable lines consisting of single-core cables with two-point bonded cable shields. The current tendency of the development of city electric networks implies an increasingly widespread use of three-phase high-voltage cable lines performed by ingleconductor cables with cross-linked polyethylene insulation. However, the cable line magnetic field can exceed the reference level for the population (0.5 μT for living space and 10 μT for an urban area). Therefore, when designing cable lines it is mandatory to calculate accurately their magnetic field using existing regulation documents and analytical solutions based on known methods. At the same time, in the case of two-point bonding, the cable shields form closed loops in which longitudinal currents are induced. These currents create an additional magnetic field that substantially changes the initial cable line magnetic field, that must be taken into account. The problem of simulation of the magnetic field of the cable line with two-point bonded cable shields can be solved numerically. However, analytical methods are more affordable for cable line designers. Also, these methods produce results with a transparent physical interpretation. However, the analytical methods of solving these problems are insufficiently studied. This is due to the lack of theoretically based methods for determining the complex amplitude of currents in the shields of three-phase cable lines and the methods of magnetic field simulating at any arrangement of phase cables. In the thesis, the features of a three-phase cable line with two-point bonded shields as the source of the magnetic field are investigated. It is shown that correct methods of calculating the magnetic field of cable lines can be created only if the currents in cable shields, which are inductively connected with the currents in cable cores, are determined. The analysis of electromagnetic processes in a three-phase cable line with two-point bonded shields based on the method of complex amplitudes is carried out. A generalized physico-mathematical model of the magnetic field of cable lines is developed. It allows to calculate the electric currents induced in shields of cables and to determine the magnetic field distribution for the arbitrary arrangement of cables. The exact expression for the magnetic field shielding factor for the trefoil cable line with two-point bonded shields is obtained. Using the Clark transformation, a simplistic expression for the magnetic field shielding factor is received for the flat cable line with twopoint bonded shields. Its error is within 5%. The possibility of the magnetic field shielding factor 2-4 times increase by ferromagnetic cores installed on cables is justified theoretically and experimentally. In this case the shielding factor depends on parameters of ferromagnetic cores, parameters of cables and their arrangement. The respective expressions for the shielding factor are obtained for trefoil and flat cable lines. The verification of the proposed physico-mathematical model and analytical expressions is performed by numerical simulation and experimentally. Methodologies of the magnetic field and root-mean-square shield currents calculating for the cable line with two-point bonded cable shields are developed.
Опис
Ключові слова
магнітне поле, трифазна кабельна лінія, двостороннє заземлення екранів, феромагнітне осердя, перетворення Кларк, автореферат дисертації, magnetic field, three-phase cable line, two-point bonded shields, ferromagnetic core, Clark transformation
Бібліографічний опис
Ткаченко О. О. Магнітне поле високовольтних кабельних ліній при двосторонньому заземленні екранів кабелів [Електронний ресурс] : автореф. дис. ... канд. техн. наук : спец. 05.09.05 / Олександр Олегович Ткаченко ; [наук. керівник Розов В. Ю.] ; Нац. техн. ун-т "Харків. політехн. ін-т". – Харків, 2019. – 22 с. – Бібліогр.: с. 18-20. – укр.