A Prewelding Pipe-Heating System

Bazarov, A. A.; Danilushkin, Aleksandr I.; Zimin, Lev S

doi:10.3103/s1068371218030045

Cited by 4 publications

(3 citation statements)

References 2 publications

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“…Процессы плавления или кристаллизации льда моделируются с помощью замены процесса движения фронта раздела жидкой и твердой фаз, в выражении (1) Сложность задачи плавления гололеда на проводах заключается в том, что необходим учет поглощения и выделения теплоты плавления. Оба эти процесса протекают одновременно.…”

Section: построение математической моделиunclassified

“…Для упрощения расчетной модели (1) изменение агрегатного состояния выполнено путем добавления теплоты плавления к величине удельной теплоемкости в узком диапазоне температур [1]. При задании перепада температуры, равного двум градусам, при котором лед переходит в жидкое состояние, получена прибавка теплоемкости 165 кДж/кг .…”

Section: построение математической моделиunclassified

“…Для более простого решения проблемы предлагается обеспечить нагрев линии за счет пропускания дополнительных реактивных токов, достаточных для формирования нужного по величине уровня мощности тепловыделения [1]. Ток в линии формируется нагрузкой подключенных потребителей и реактивной мощностью реактора, специально подключенного в конце линии и имеющего индуктивность L. Одновременное подключение в начале линии батареи конденсаторов, имеющих суммарную емкость С, позволяет компенсировать реактивную мощность и разгрузить питающий трансформатор от реактивных токов.…”

Section: Introductionunclassified

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Modeling of thermal processes when melting ice on power lines

Bazarov,

Budko

2023

Vestnik of Samara State Technical University. Technical Science

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An analysis of the problem of ice formation on power line wires was carried out, and a review of work in the field of melting ice on various lines was carried out. Existing achievements and problems are noted. One of the reasons for the low equipment of lines with automated melting systems is the need to transfer the line from the operating state to the melting mode. One way to solve the problem is to combine these modes by loading the line with additional current without increasing the power transmitted to consumers. A set of issues on modeling thermal processes in the ice shell of power line wires during ice melting is considered. Limiting the power of heat generation in wires leads to the need to build a sufficiently accurate mathematical model to guarantee melting at different values of wind speed and temperature. A study of wire heating processes was carried out using models of stationary and non-stationary thermal conductivity. An algorithm is proposed for solving the thermal problem when a heated wire penetrates an ice shell, based on simulating the movement of the interface between the solid and liquid phases of water. The features of modeling the melting and crystallization process using a numerical method are described. When ice transitions to a molten state, melting reflects a change in density and the formation of an air gap, accompanied by a significant decrease in heat flows to the lower region of the ice shell. The results of numerical modeling of the process of melting an ice shell with a wire at different values of the convective heat transfer coefficient are presented. When analyzing the modeling results, conditions were identified for the occurrence of unacceptable overheating of a wire freed from ice. Various options for constructing a control system for the smelting process have been proposed to prevent overheating of the wire.

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Section: построение математической моделиunclassified

Section: Introductionunclassified

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Modeling of thermal processes when melting ice on power lines

Bazarov,

Budko

2023

Vestnik of Samara State Technical University. Technical Science

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Increase in reliability of frequency converters of agricultural objects

Tulegenov¹,

Kiesh²,

Bespalov

2019

IOP Conf. Ser.: Earth Environ. Sci.

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The article presents ways to improve reliability of agricultural semiconductor frequency converters. It is shown that an increase in reliability of semiconductor converters can be achieved increasing the power reserve. At the same time, if the economic indicator is chosen as an optimization criterion, the coefficient of failure-free operation reaches no more than 0.8. In the event that resulting coefficient of failure-free operation is allowed according to operating conditions, selected criterion can be successfully applied at design stage of semiconductor converters.

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Improving the reliability of energy facilities

Bukhanov

Zhuravleva

Kornienko³

2019

IOP Conf. Ser.: Mater. Sci. Eng.

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The article analyzed and identified the main sources of interference, disrupting the work and reliability indicators of the system, which can lead to malfunction of system of microprocessor relay protection and automation for electric stations and substations, as well as elements and actuators of open distribution devices. According to official data, modern microprocessor-based relay automation systems operate with a reliability coefficient that is not lower than 0.998. Further increase in reliability requires the development of technical measures, namely, requires the use of power and signal cables that must meet the requirements for specific parameters of inductance, capacitance and active resistance, and also requires the use of special placement of cross sections of conductors inside the cable. Secondly, it is shown that to increase the reliability of information transmission it is necessary to switch to serial communication channels, but the amount of information per channel should be strictly limited. The estimation of economic indicators of the system and its dependence on the reliability of the system is given. Thus, with an increase in reliability by 1.5-2 times, it is necessary to increase the cost of design and commissioning of such a system by about 2 times. It is recommended to use in addition to the regulated maintenance procedures a mandatory assessment of the level of interference in the system in order to maintain a stable and reliable operation of the relay automation system. Experimental and calculated data confirmed that the most difficult situation to ensure the reliability of the system is associated with thunderstorms and lightning. This circumstance dictates the necessity of evaluation and measuring the parameters of a common system of earthing. The methods of evaluation and diagnosis of faulty components of the system are proposed.

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A Prewelding Pipe-Heating System

Cited by 4 publications

References 2 publications

Modeling of thermal processes when melting ice on power lines

Modeling of thermal processes when melting ice on power lines

Increase in reliability of frequency converters of agricultural objects

Improving the reliability of energy facilities

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