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Bushings

The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

Zongren Peng – 1st expert on this subject based on the ideXlab platform

  • research on the deterioration process of electrical contact structure inside the 500 kv converter transformer rip Bushings and its prediction strategy
    Iet Generation Transmission & Distribution, 2019
    Co-Authors: Huidong Tian, Qingyu Wang, Shiyi Zhou, Zehua Wu, Jinyin Zhang, Zongren Peng

    Abstract:

    Extra high-voltage converter transformer resin impregnated paper (RIP) bushing is used as the outlet device of the converter transformer, its safe operation is directly related to the reliability of the power system. Under the long-term effects of high current, strong mechanical stress and abrasion, the contact resistance of connection structure inside the bushing is prone to deteriorate. When the local overheating increases to a certain level, the insulation performance of bushing will decline and may lead to penetrating discharge. Therefore, it is vital to develop strategies for predicting the overheating fault of RIP Bushings. In this study, firstly, one typical overheating fault of RIP bushing induced by the contact deterioration was diagnosed according to the fretting corrosive model and SF
    6
    decomposition process. Secondly, using the three-dimensional electromagnetic-thermal-fluid finite element method, the temperature distributions of RIP bushing under the different overheating degrees were simulated. Finally, based on the maintenance experience and simulation results, the diagnosis strategies were proposed. The diagnosis principle and prediction strategies were successfully helped to maintain the faulted RIP Bushings and wall Bushings before a destructive overheating accident could occur, which provide a basic reference for the fault prediction and improvements of relative standards.

  • Research on the deterioration process of electrical contact structure inside the ±500 kV converter transformer RIP Bushings and its prediction strategy
    IET Generation Transmission & Distribution, 2019
    Co-Authors: Huidong Tian, Qingyu Wang, Shiyi Zhou, Zehua Wu, Jinyin Zhang, Zongren Peng

    Abstract:

    Extra high-voltage converter transformer resin impregnated paper (RIP) bushing is used as the outlet device of the converter transformer, its safe operation is directly related to the reliability of the power system. Under the long-term effects of high current, strong mechanical stress and abrasion, the contact resistance of connection structure inside the bushing is prone to deteriorate. When the local overheating increases to a certain level, the insulation performance of bushing will decline and may lead to penetrating discharge. Therefore, it is vital to develop strategies for predicting the overheating fault of RIP Bushings. In this study, firstly, one typical overheating fault of RIP bushing induced by the contact deterioration was diagnosed according to the fretting corrosive model and SF6 decomposition process. Secondly, using the three-dimensional electromagnetic-thermal-fluid finite element method, the temperature distributions of RIP bushing under the different overheating degrees were simulated. Finally, based on the maintenance experience and simulation results, the diagnosis strategies were proposed. The diagnosis principle and prediction strategies were successfully helped to maintain the faulted RIP Bushings and wall Bushings before a destructive overheating accident could occur, which provide a basic reference for the fault prediction and improvements of relative standards.

  • Study on frequency domain dielectric spectroscopy of epoxy resin impregnated paper Bushings under damp conditions
    The Journal of Engineering, 2019
    Co-Authors: Zuoming Xu, Wei Hu, Fuquan Yi, Guanpeng Hu, Xin Wang, Zongren Peng

    Abstract:

    Epoxy resin impregnated paper (RIP) Bushings are widely used as transformer Bushings and wall Bushings, but this type of bushing is easy to be dampened. In order to study the effect of moisture on the Bushings‘ insulation performance, a test device was established to simulate the moisture absorption process in the air or N2 gas. Based on the frequency-domain dielectric spectroscopy (FDS) method, FDS curves that indicate the dielectric loss factor (tan δ) and capacitance (C) under different frequencies were tested and analysed. The results demonstrated that the FDS curve moves to the high frequency direction with the increase of the moisture content, and there exist minus tan δ and a negative peak in low-frequency band. Since the moisture content is much lower than in the air, tan δ and C under power frequency of the bushing almost unchanged in the N2 gas. However, the tan δ under 0.1 Hz increases sharply with the increase of trace moisture, and the higher moisture content, the greater increase rate. A damp diagnosis method for RIP Bushings is proposed based on the FDS curves’ frequency translation characteristics and tan δ variation law. Also the results can give references for RIP Bushings‘ insulation diagnosis.

Milad Akbari – 2nd expert on this subject based on the ideXlab platform

  • heat analysis of the power transformer Bushings in the transient and steady states considering the load variations
    Applied Thermal Engineering, 2017
    Co-Authors: Milad Akbari, Mehdi Allahbakhshi, Rashid Mahmoodian

    Abstract:

    Abstract Bushings are considered as one of the main components of the power transformers. This is due to the fact that the reliable and efficient performance of the Bushings significantly influences the reliability of the transformers which, in turn, are counted as the fundamental part of the power systems. The thermal behaviour of the Bushings, as a consequence of the power dissipation, significantly affects the bushing’s performance and design. In this paper, a novel algorithm is proposed for the heat analysis of the Bushings. This algorithm aims at specifying the hot spot temperature and the temperature distribution of the bushing. Therefore, the problem is formulated using the Joule Heating equations as the partial differential equations for both transient and steady states. Then, the finite element method is employed to solve the problem. The algorithm is implemented on an oil-impregnated paper bushing. In the steady state, the temperature distribution of the whole bushing is determined. In addition, the effects of different currents on the location and magnitude of the hot spot temperature have been investigated. In the transient state, three overload scenarios are simulated two of which are from the IEEE C57.19.100 and IEC 60076-7 standards. In addition, the effects of the wind speed and electric load on the bushing’s temperature distribution for 48 h have been investigated.

  • heat analysis of the power transformer Bushings using the finite element method
    Applied Thermal Engineering, 2016
    Co-Authors: Mehdi Allahbakhshi, Milad Akbari

    Abstract:

    Abstract Reliability of power transformers significantly depends on the performance of their Bushings and bushing lifetime is mainly dependent on its hottest spot temperature, which is caused by the power dissipation in the bushing’s conductor. In this paper, the thermal analysis of the bushing is firstly performed in two-dimensional space using the differential equations. Then, the Finite Element Method (FEM) is employed to determine a bushing’s temperature distribution and specify its hottest spot. The effects of increasing the temperature on the bushing’s conductor are also investigated and the results are compared in different currents. The proposed method calculates the temperature distribution in all parts of bushing including conductor surface, paper, porcelain and oil. It is useful for manufacturer and utilities to evaluate the insulation design, temperature distribution and loss of insulation life.

Rashid Mahmoodian – 3rd expert on this subject based on the ideXlab platform

  • heat analysis of the power transformer Bushings in the transient and steady states considering the load variations
    Applied Thermal Engineering, 2017
    Co-Authors: Milad Akbari, Mehdi Allahbakhshi, Rashid Mahmoodian

    Abstract:

    Abstract Bushings are considered as one of the main components of the power transformers. This is due to the fact that the reliable and efficient performance of the Bushings significantly influences the reliability of the transformers which, in turn, are counted as the fundamental part of the power systems. The thermal behaviour of the Bushings, as a consequence of the power dissipation, significantly affects the bushing’s performance and design. In this paper, a novel algorithm is proposed for the heat analysis of the Bushings. This algorithm aims at specifying the hot spot temperature and the temperature distribution of the bushing. Therefore, the problem is formulated using the Joule Heating equations as the partial differential equations for both transient and steady states. Then, the finite element method is employed to solve the problem. The algorithm is implemented on an oil-impregnated paper bushing. In the steady state, the temperature distribution of the whole bushing is determined. In addition, the effects of different currents on the location and magnitude of the hot spot temperature have been investigated. In the transient state, three overload scenarios are simulated two of which are from the IEEE C57.19.100 and IEC 60076-7 standards. In addition, the effects of the wind speed and electric load on the bushing’s temperature distribution for 48 h have been investigated.