Dielectric Breakdown of Transformer Insulation Materials Under Cryogenic and Room Temperatures

2008 ◽  
Author(s):  
Horatio Rodrigo ◽  
Wolfgang Baumgartinger ◽  
Aniket Ingrole ◽  
Z (Richard) Liang ◽  
Danny George. Crook ◽  
...  
Keyword(s):  
Dielectric Breakdown ◽  
Insulation Materials ◽  
Transformer Insulation

Ameliorated Dielectric Performances of UV-Initiated Auxiliary Crosslinking Polyethylene

2021 ◽  
Vol 16 (7) ◽  
pp. 1037-1046
Author(s):  
Ming-Hao Lv ◽  
Wei-Chao Zhang ◽  
Wei Guo ◽  
Liang Du
Keyword(s):  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Electrical Conductance ◽  
Polyethylene Matrix ◽  
Crosslinking Degree ◽  
Insulation Materials ◽  
Crosslinking Process ◽  
High Level ◽  
Crosslinking Reactions ◽  
Xlpe Insulation

In photon-initiated crosslinking reactions of polyethylene molecules, the auxiliary crosslinkers in form of either monomer or homopolymer will cause bridging connections between polymeric molecules by transforming the irradiated photon energy to chemical energy under the assistance of photon-initiators, which can improve photon-initiation quantum efficiency and crosslinking uniformity. In the present study, the auxiliary crosslinkers of TAIC, TAC and TMPTA combining the macromolecular photon-initiator of BPL are employed into the ultraviolet (UV)-initiation technology to develop high-level crosslinked polyethylene (XLPE) insulation materials, whilst elucidating the structural and electrical mechanisms of the dielectric amelioration deriving from auxiliary crosslinking schemes. The specified photosensitive auxiliary crosslinkers can chemically bridge polyethylene molecules in the UV-initiated polyethylene crosslinking process, which can effectively promote polyethylene crosslinking degree but will slightly abate polyethylene crystallinity. Whereas, the orientation polarization and relaxation of molecular electric-dipoles on auxiliary crosslinkers cause additional dielectric permittivity and loss respectively, which will probably reduce insulation performances of XLPE. By contrast to XLPE benchmark, especially for grafting auxiliary crosslinker TAIC with the multiple-coupling carbonyl groups in a ring-conjugation, the preferable deep charge-traps can be introduced into polyethylene matrix to effectively improve electrical conductance and AC dielectric breakdown strength. This study provides experimental basis for developing the photon-initiated XLPE insulation materials with advanced dielectric performances required for manufacturing high-voltage grade cables.

scholarly journals Short and long term behavior of functionally filled polymeric insulating materials for HVDC insulators in compact gas-insulated systems

2018 ◽  
Author(s):  
Michael Tenzer ◽  
Maximilian Secklehner ◽  
Volker Hinrichsen
Keyword(s):  
Electric Conductivity ◽  
High Voltage ◽  
Dielectric Breakdown ◽  
Dielectric Strength ◽  
Filled Polymers ◽  
Field Stress ◽  
Insulation Materials ◽  
Current Transmission ◽  
Short And Long Term

<p>Conventional insulators optimized for high-voltage alternating current transmission tend to accumulate surface and volume charges in direct voltage applications. This is especially true for gas-insulated systems, where the surrounding gas is extremely dry, thus having very low conductivity. This may result in a strong decrease of the dielectric strength of the insulators and can lead to dielectric breakdown, especially when polarity reversals are applied. Main challenges for the development of HVDC insulators are avoiding surface and volume charge accumulations and featuring both suitable capacitive and resistive field distributions. The use of polymeric insulation materials filled with functional fillers of defined low and possibly non-linear, field dependent electric conductivity avoids these charge accumulations. <br />Several specimens of polymeric insulation materials of different, controlled conductivities for high field stress applications were produced and experimentally investigated for this contribution. Since electric conductivity depends on parameters such as temperature, humidity or long term ageing, the longterm behavior of the specimens was investigated in 1000 h tests under temperature and electrical field stress. Furthermore, tests in a high-voltage gas insulated test setup were performed in order to determine the dielectric strength of the filled polymers under high electric stationary and transient fields as present in gas insulated systems. Results of these investigations are presented and discussed in detail in this contribution.</p>

scholarly journals Influence of Various Temperatures on the Drying Time of 132 KV Transformer Insulations in Vapour Phase Drying Process

2020 ◽  
Vol 9 (3) ◽  
pp. 3072-3078
Keyword(s):  
Moisture Content ◽  
Vapour Phase ◽  
The State ◽  
Vacuum Drying ◽  
Drying Process ◽  
Drying Time ◽  
Insulation Materials ◽  
Transformer Insulation ◽  
Cellulose Insulation ◽  
Very High

Transformers are required to handle very high levels of voltage and hence proper insulation is very important in transformers. As of now, the most preferred form of insulation in transformers is cellulose based. The state of cellulose insulation materials like paper & pressboards determines the life end of a transformer. Paper with 1.5% moisture content ages 10 times faster than with only 0.3% moisture. For obvious reasons, it is very important that the moisture is removed from transformer insulation. Vacuum drying has been conventionally used in industries for insulation drying but, as of today the latest technology available is the vapour phase drying process. This paper evaluates the influence of temperatures at various locations on the drying time of the 132kv transformer insulations in vapour phase drying process.

Effects of Electrical Discharges in Low Pressure Gases on the Morphology of Polyethylene Crystals

1974 ◽  
Vol 32 ◽  
pp. 544-545
Author(s):  
L.H. Bolz ◽  
D.H. Reneker
Keyword(s):  
Power Distribution ◽  
Electrical Discharge ◽  
Dielectric Breakdown ◽  
Ionic Species ◽  
Low Pressure ◽  
Polymer Surfaces ◽  
Electrical Discharges ◽  
Adhesive Bonds ◽  
Power Distribution Lines ◽  
Modification Of The Surface

The attack, on the surface of a polymer, by the atomic, molecular and ionic species that are created in a low pressure electrical discharge in a gas is interesting because: 1) significant interior morphological features may be revealed, 2) dielectric breakdown of polymeric insulation on high voltage power distribution lines involves the attack on the polymer of such species created in a corona discharge, 3) adhesive bonds formed between polymer surfaces subjected to such SDecies are much stronger than bonds between untreated surfaces, 4) the chemical modification of the surface creates a reactive surface to which a thin layer of another polymer may be bonded by glow discharge polymerization.

Sign in / Sign up

Export Citation Format

Share Document