PD Characteristics in Transformer Oil under AC Condition

2014 ◽  
Vol 492 ◽  
pp. 186-189
Author(s):  
Ji Chong Liang ◽  
Tian Zheng Wang ◽  
Kang Ning Wang ◽  
Jun Hao Li
Keyword(s):  
Electric Field ◽  
High Voltage ◽  
Applied Voltage ◽  
Partial Discharge ◽  
Electrode System ◽  
Transformer Oil ◽  
Pulse Burst ◽  
Transformer Oils ◽  
Pattern Display ◽  
Insulation Condition

Partial discharge (PD) detection is a technique widely used for high voltage equipment insulation condition assessment. The metal protrusion is a situation that often appear in transformer. Metal protrusion will cause the electric field concentration and lead to partial discharge. In this paper, PD characteristics in transformer oils are examined under AC conditions, using a needle-to-plane electrode system. The PD activity in transformer oil is confirmed as appearing in pulse burst form and the PD number and amplitude will increase with the applied voltage increase. The PRPD pattern display behavior typical of corona PD in oil.

scholarly journals Clarifications on the Behavior of Alternative Gases to SF6 in Divergent Electric Field Distributions under AC Voltage

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1065
Author(s):  
Houssem Eddine Nechmi ◽  
Michail Michelarakis ◽  
Abderrahmane (Manu) Haddad ◽  
Gordon Wilson
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Partial Discharge ◽  
Mean Value ◽  
Electrode System ◽  
Polarity Reversal ◽  
Buffer Gas ◽  
Co2 Gas ◽  
Breakdown Mechanism ◽  
Positive Cycle

Negative and positive partial discharge inception voltages and breakdown measurements are reported in a needle-plane electrode system as a function of pressure under AC voltage for natural gases (N2, CO2, and O2/CO2), pure NovecTM gases (C4F7N and C5F10O) and NovecTM in different natural gas admixtures. For compressed 4% C4F7N–96% CO2 and 6% C5F10O–12% O2–82% CO2 gas mixtures, the positive-streamer mode is identified as the breakdown mechanism. Breakdown and negative partial discharge inception voltages of 6% C5F10O–12% O2–82% CO2 are higher than those of 4% C4F7N–96% CO2. At 8.8 bar abs, the breakdown voltage of 6% C5F10O–12% O2–82% CO2 is equal to that of 12.77% O2–87.23% CO2 (buffer gas). Synergism in negative partial discharge inception voltage/electric field fits with the mean value and the sum of each partial pressure individually component for a 20% C4F7N–80% CO2 and 6% C5F10O–12% O2–82% CO2, respectively. In 9% C4F7N–91% CO2, the comparison of partial discharge inception electric fields is Emax (CO2) = Emax(C4F7N), and Emax (12.77% O2–87.23% CO2) = Emax(C5F10O) in 19% C5F10O–81%(12.77% O2–87.23% CO2). Polarity reversal occurs under AC voltage when the breakdown polarity changes from negative to positive cycle. Polarity reversal electric field EPR was quantified. Fitting results show that EPR (CO2) = EPR(9% C4F7N–91% CO2) and EPR(SF6) = EPR (22% C4F7N–78% CO2). EPR (4% C4F7N–96% CO2) = EPR (12.77% O2–87.23% CO2) and EPR (6% C5F10O–12% O2–82% CO2) < EPR (4% C4F7N–96% CO2) < EPR (CO2).

Online Partial Discharge Insulation Condition Monitoring of Complete High-Voltage Networks

2019 ◽  
Vol 55 (1) ◽  
pp. 1021-1029 ◽  
Author(s):  
Lee Andrew Renforth ◽  
Riccardo Giussani ◽  
Michael T. Mendiola ◽  
Lewis Dodd
Keyword(s):  
Condition Monitoring ◽  
High Voltage ◽  
Partial Discharge ◽  
Insulation Condition

Partial Discharges Registration in Transformer Oil at the ‘Point-Plane’ Electrode System

2014 ◽  
Vol 698 ◽  
pp. 615-620 ◽  
Author(s):  
Aleksandr Bychkov ◽  
Sergey Korobeynikov ◽  
Aleksandr Ovsyannikov
Keyword(s):  
Partial Discharge ◽  
Experimental Studies ◽  
Electrode System ◽  
Partial Discharges ◽  
Transformer Oil ◽  
Optical Methods ◽  
Time Duration ◽  
Negative Point ◽  
Different Types ◽  
System Point

The results of the experimental studies of partial discharges in GK transformer oil with electrode system “point-plane” that provide sharp inhomogeneous electric field are presented. It was found out that two types of partial discharge pulses which differ in form and time duration appeared at the negative point polarity of the needle. The study of different types of pulses was conducted by electric and electro-optical methods of partial discharge registration.

scholarly journals Detection and Localization of Partial Discharge in Transformer Oil and Winding using UHF Method

2020 ◽  
Vol 9 (7) ◽  
pp. 304-308
Keyword(s):  
Electromagnetic Waves ◽  
Power Transmission ◽  
Dielectric Breakdown ◽  
Partial Discharge ◽  
Electrical Insulation ◽  
Transformer Oil ◽  
Insulation Failure ◽  
Voltage Stress ◽  
Detection And Localization ◽  
Insulation Condition

Transformers are important part in power transmission. One of the serious faults that is seen in transformers is electrical insulation failure. Insulation failure is usually initiated by partial discharges (PD). Due to high voltage stress, the fluid insulation in electrical system or a small solid portion can get dielectric breakdown, this is known as partial discharge and this does not create a space between the conductors. The accurate location of PD is an effective method for assessing the existing electrical insulation condition and preventing future accidents. PD is detected by many methods, but for onsite detection of PD, one of the efficient methods is sensing the electromagnetic waves radiated by the discharge source with a frequency range that can go up to 3GHz. In this technique Ultra High Frequency (UHF) sensors are mounted on the transformer tank to measure these waves. This provides a suitable solution for on-site detection of insulation failure in power transformers.

scholarly journals Simulations of High Non-Uniform Electric Field in Dielectric Barrier Electrode System

2021 ◽  
Vol 18 (14) ◽  
Author(s):  
Pitchasak CHANKUSON ◽  
Mudtorlep NISOA
Keyword(s):  
Electric Field ◽  
High Voltage ◽  
High Intensity ◽  
Dielectric Materials ◽  
Electrode System ◽  
Ozone Production ◽  
Uniform Electric Field ◽  
Electrode Geometry ◽  
Dielectric Barrier ◽  
Fine Mesh

An electric field in the dielectric barrier electrode system is necessary for ozone production because ozone is produced by the electric discharge of O2 under a high-intensity electric field. The gas discharge plasmas contain energetic particles, such as electrons, ions, atoms, and radicals. The recombination of the O atom and O2 in the plasma will form O3. In this paper, the dependence of DC electric field formation on electrode geometry and the gap between electrodes and dielectric materials were examined by using computational modeling. Thus, a set of electrode geometry, gap distance, and dielectric material were obtained for high-intensity and uniform electric field generation. The COMSOL Multiphysics software was used for the modeling. Among the electrode geometries of plate-plate, pin-plate and mesh-plate, the mesh-plate generated high-intensity and uniform electric field. In the modeling, dielectric materials, including quartz, mica, alumina, and water, were compared. The highest intensity of electric field occurred on the water surface. HIGHLIGHTS When the gap distance between two parallel electrodes is less than 100 mm, the electric field in the gap is constant, independent of the space A high-intensity and uniform electric field is generated in the gap between the dielectric and grounded electrodes when a fine mesh high-voltage electrode is utilized With the fine mesh electrode, the electric field is about two times higher than the conventional plate electrodes, whereas the electric field uniformity was about 90 %. Therefore the barrier discharge will be initiated with lower high voltage GRAPHICAL ABSTRACT

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