scholarly journals Applying HF and VHF/UHF Partial Discharge Detection for Distribution Transformer

2020 ◽  
Author(s):  
Sakda Maneerot ◽  
Masaaki Kando ◽  
Norasage Pattanadech
Keyword(s):  
High Frequency ◽  
Partial Discharge ◽  
Mineral Oil ◽  
Surface Discharge ◽  
Distribution Transformer ◽  
Impregnation Process ◽  
Distribution Transformers ◽  
Insulating Liquid ◽  
Paper Insulation ◽  
Natural Ester

This paper represents application of high frequency (HF) and very high frequency/ultrahigh frequency (VHF/UHF) partial discharge (PD) detection for a distribution transformer. A capacitive sensor is used to detect the HF electric field caused by charge transfer inside oil–paper insulation due to PD at the defect site, and an electromagnetic sensor or antenna is used for detecting electromagnetic PD transients in the air outside the investigated transformer in the near-field region. Three types of artificial PD sources in air and insulating liquid, which are corona discharge, surface discharge and air void discharge in pressboard, were investigated. Three identical distribution transformers were rated at 22 kV, 400 V and 50 kVA, and were designed and constructed. The first transformer was filled with mineral oil, the second was filled with natural ester and the third was filled with palm oil. The PD generated by the air-filled voids in the insulating papers and pressboards of these transformers with five different conditions were investigated, i.e., non-impregnated paper, impregnated paper for 3 hours, 6 hours, 9 hours and 12 hours. The impregnation process was done with 65°C liquid temperature, and the pressure in the oven was around 5 mbar. From the experimental results, it can be concluded that the electromagnetic PD transients radiated from the corona discharge of both high-voltage (HV) and low-voltage sides in the air are in the VHF range, and surface discharge frequency is extended up to the UHF range. For the PD in the insulating liquid, the phase resolved PD (PRPD) pattern in the HF range is a valuable tool to characterize the PD sources. The PD in an air-filled void inside the insulating paper of the mineral oil transformer is obviously different compared with those of the natural ester transformer and the palm oil transformer. For the manufacturing of distribution transformers in this research, it is found that after the paper insulation is dried out, the impregnation process for a period of 9 hours is suitable for improving the oil–paper insulation with an acceptable PD level. This paper is the cross-field application by applying the antenna and communication theory for detecting the discharge problems in HV equipment.

scholarly journals Effect of Moisture on the Thermal Conductivity of Cellulose and Aramid Paper Impregnated with Various Dielectric Liquids

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4433 ◽  
Author(s):  
Grzegorz Dombek ◽  
Zbigniew Nadolny ◽  
Piotr Przybylek ◽  
Radoslaw Lopatkiewicz ◽  
Agnieszka Marcinkowska ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Linear Equation ◽  
Heat Transport ◽  
Mineral Oil ◽  
Experimental Database ◽  
Synthetic Ester ◽  
Dielectric Liquids ◽  
Paper Insulation ◽  
The Impact ◽  
Natural Ester

This paper presents the effect of the impact of moisture in paper insulation used as insulation of transformer windings on its thermal conductivity. Various types of paper (cellulose and aramid) and impregnated (mineral oil, synthetic ester, and natural ester) were tested. The impact of paper and impregnated types on the changes in thermal conductivity of paper insulation caused by an increase in moisture were analyzed. A linear equation, describing the changes in thermal conductivity due to moisture, for various types of paper and impregnated, was developed. The results of measuring the thermal conductivity of paper insulation depending on the temperature are presented. The aim of the study is to develop an experimental database to better understand the heat transport inside transformers to assess aging and optimize their performance.

Aging of Paper Insulation in Natural Ester & Mineral Oil

2012 ◽  
Vol 2 (3) ◽  
pp. 141-146 ◽  
Author(s):  
Yunus Biçen ◽  
Yusuf Çilliyüz ◽  
Faruk Aras ◽  
Guzide Aydugan
Keyword(s):  
Mineral Oil ◽  
Paper Insulation ◽  
Natural Ester

Gas generation in natural ester and mineral oil under partial discharge and sparking faults

2013 ◽  
Vol 29 (5) ◽  
pp. 62-70 ◽  
Author(s):  
Zhongdong Wang ◽  
Xin Wang ◽  
Xiao Yi ◽  
Sitao Li ◽  
John Hinshaw
Keyword(s):  
Partial Discharge ◽  
Mineral Oil ◽  
Gas Generation ◽  
Natural Ester

scholarly journals KARAKTERISTIK SURFACE PARTIAL DISCHARGE DI SEKITAR ANTARMUKA PCB PADA PELAT-PELAT ELEKRODA PADA ISOLASI UDARA DAN MINYAK

2020 ◽  
Vol 6 (2) ◽  
pp. 65-73 ◽  
Author(s):  
Neris Peri Ardiansyah ◽  
Resa Pramudita
Keyword(s):  
High Frequency ◽  
Partial Discharge ◽  
Current Transformer ◽  
Surface Discharge ◽  
High Frequency Current ◽  
Inception Voltage ◽  
Frequency Current

Penggunaan peralatan tegangan tinggi pada konverter elektronik daya atau modul daya memiliki pengaruh terhadap sistem isolasi peralatan yang digunakan. Efek yang dihasilkan adalah pelepasan sebagian atau partial discharge (PD), dimana hal tersebut depengaruhi oleh bentuk tegangan, yang mana fenomena PD ini adalah awal mula terjadinya kegagalan dalam suatu peralatan. Pada penelitian ini dilakukan Pengukuran PD dengan mengacu pada Standar IEC 60270 yang menggunakan metode elektrik sebagai pengukuran yang digunakan untuk pengujian PD pada bahan PCB dengan alat ukur yang digunakan adalah RC detektor dan High Frequency Current Transformer (HFCT). Pengukuran PD dilakukan dengan membuat model elektroda yang digunakan pada pengujian untuk membuat sumber PD. Elektroda yang digunakan adalah model elektroda Homogen pelat-pelat. Pengujian pada PCB dilakukan untuk mengetahui karakteristik surface discharge pada disekitar antarmuka pelat-pelat elektroda. Parameter yang digunakan dalam pengukuran yaitu Partial Discharge Inception Voltage (PDIV), Partial Discharge Extinction Voltage (PDEV), Bentuk Gelombang PD, dan Pola Phasa PD.

scholarly journals Influence of Aging Derivatives on Properties of Natural Ester Oil

2020 ◽  
Vol 9 (4) ◽  
pp. 2597-2600 ◽  
Keyword(s):  
Mineral Oil ◽  
Transformer Oil ◽  
Critical Parameters ◽  
Uv Spectrum ◽  
Service Period ◽  
Before And After ◽  
Furanic Compounds ◽  
Paper Insulation ◽  
Transmission And Distribution ◽  
Natural Ester

Transformers are the critical component in the power system, which is used for transmission and distribution purposes. Traditionally mineral oil has been used as the liquid insulation medium in the transformer. Owing to poor bio - degradability and availability, it has been widely studied to replace mineral oil with natural ester oil. During the service period of the transformer, oil insulation and paper insulation gets degraded due to aging. This aging results in the formation of furanic compounds in the oil insulation, which will affect the performance of oil insulation and thus the transformer life. In this proposed work, an effort is made to analyze the critical parameters before and after the inclusion of an aging derivative of 2–furfuraldehyde (2-FAL). 2-FAL has been added in the proportion of 20 ppm to investigate the oil’s properties such as breakdown voltage, viscosity, flash point, fire point, and peak absorbance of the UV spectrum. It is observed that there is a lesser impact on the properties with the addition of 20ppm of 2-FAL. Hence it is suggested that the various concentration of 2-FAL may be added to check the quality of oil for further applications.

A review of critical evaluation of natural ester vis-a-vis mineral oil insulating liquid for use in transformers: Part II

2016 ◽  
Vol 23 (3) ◽  
pp. 1705-1712 ◽  
Author(s):  
Dhruvesh M. Mehta ◽  
P. Kundu ◽  
A. Chowdhury ◽  
V. K. Lakhiani ◽  
A. S. Jhala
Keyword(s):  
Critical Evaluation ◽  
Mineral Oil ◽  
Insulating Liquid ◽  
Natural Ester
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