Dissertation > Excellent graduate degree dissertation topics show

Space Charge Properties of Two Kinds of Oil-paper Under DC Electric Field During the Process of Thermal Aging

Author: LiWei
Tutor: LiaoRuiJin
School: Chongqing University
Course: Electrical Engineering
Keywords: Transformer insulation paper synthetic fibers space charge thermal aging
CLC: TM215.6
Type: Master's thesis
Year: 2011
Downloads: 81
Quote: 2
Read: Download Dissertation

Abstract


Transformer is one of the core equipment of energy conversion in power system, the reliability of its operation is related to the operation of power grid stability and security directly. During its normal operation of insulation paper in transformer, space charge will be generated to effect the field distribution of material when under the electric field. Paper will be also under the action of thermal stress and generate thermal degradation, and lead to deterioration of insulation. These phenomenen will impact the improvement of insulating paper life and limited service life of power transformers. Because people’s understanding with the relationship between thermal aging of paper and space charge transport properties is still limited, it will impact the development of new anti-aging insulation material, and restrict the development of power transformer insulation to a certain extent.This paper analyzes the space charge characteristics between new synthetic fiber insulation paper named NOMEX and traditional plant cellulose insulation paper when under the action of DC electric field, and research the evolution of total charge amount in insulation paper when under the DC field and remove the field, and discuss the charge transport properties of inject, migrate, accumulate, decay in two insulation materials. Finally, the total space charge decay curves of plant cellulose insulation paper were fitted by using the total charge exponential decay model, and extract two characteristic parameters of decay time constantτand the half-life t1/2 to characterize the decay capability of the residual space charge in insulation paper under different thermal aging status.The mainly conclusions in this paper are as follows:①NOMEX paper have a higher threshold than cellulose paper. Thermal aging will influence the space charge characteristics of cellulose paper dramaticlly, the amount of charge injection increase and injection rate slowed down gradually, threshold of charge injection decreased. The differences of pace charge characteristics of insulating paper under thermal aging process are lower.②Early in the thermal aging, the amount and dissipation rate of residual charge in NOMEX paper are lower than cellulose paper. The amount and dissipation rate of residual charge in NOMEX paper dropped further under thermal aging, but the amount of residual charge in cellulose paper increase and dissipation rate solwed up significantlly.③The polarity of master charge in two insulation materials are changed observably in the process of thermal aging. Injection rate of master charge in cellulose paper is greater than NOMEX paper.④The distribution density and the depth of trap are enlaged but the charge mobility reduced in thermal aging. The capbility of charge mobility and transport in NOMEX paper are lower than cellulose paper.⑤total space charge decay curve of cellulose paper is submit to exponential function better, and decay time constantτand half-life t1/2 could characterize the decay capability of the total residual charge preferably.

Related Dissertations

  1. The Equivalent Circuit Model of Radial Vibration Mode Piezoelectric Transformer and Its Application,TM406
  2. Study on the Mechanism of Partial Discharge Emitting Ultrasonic Wave and Propagation Property Within Power Transformers,TM855
  3. Substation Integrated Early Warning System and Application,TM76
  4. Research on High Efficient LED Switching Power Supply of Constant-current,TN312.8
  5. GPRS-based transformer fault diagnosis system,TM407
  6. Design and Implementation of petrochemical enterprises substation operation system,TP311.52
  7. Dynamic Voltage Restorer Based on Super-capacitor,TM761.1
  8. Fuzzy Control System Design of Transformer Cooler,TP273.4
  9. Research on Signal Processing Unit of Optical Voltage Transformer,TM451.6
  10. Research of Embedded Merging Unit Based on IEC61850,TM45
  11. Research on Electronic Voltage Transformer Based on Capacitive Voltage Divider,TM451
  12. The Research of Electronic Current Transformer and Its Communication Interface,TM452
  13. Calibration and Online Monitoring System for Electronic Transformer Based on IEC61850-9,TM45
  14. Research on Series Resonant High Voltage Capacitor Charging Power Supply,TM53
  15. The Study on the Method of Structural Dynamic Modeling and Analysis of Wind Power Transformers,TM41
  16. The Simulation Renserch of New Series Hybrid Active Power Filter and Some Related Problems Analysis,TN713.8
  17. Conventional Substation Analysis and Design of Renovation Project of Integrated Automation,TM63
  18. Research on Installation and Testing Technique on 500kV Three Phases Compact Transformer,TM407
  19. Research on Trigger System of Surface-breakdown High-voltage Switch,TM564
  20. Electronic Voltage Transformers and the Harmonic Voltage Measurements,TM451
  21. Research on Dynamic Voltage Restorer Based on Three Single-phase H Bridge,TM464

CLC: > Industrial Technology > Electrotechnical > Electrical materials > Insulating materials,dielectric,and its products > Solid dielectric > Fiber insulating materials and their products
© 2012 www.DissertationTopic.Net  Mobile