KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 9 of 9

Some of the metrics are blocked by your
consent settings
The Study of Partial Discharge of a Decommissioned 11kV Rotating Machine
(2024-01-01)
Waiwicha, Supisara
;
Monkolsatitpong, Suriya
;
Inwanna, Woranan
;
Vanijkirati, Parada
;
Jeenmuang, Siwakorn
Over time the insulation system of the stator winding in machinery will gradually lose electrical and mechanical strength due to factors such as thermal, electrical, ambient, and mechanical stressors. At a certain point, the material will deteriorate significantly to the extent that the insulation breaks down or cracks under normal operating voltages, due to transient electrical or mechanical situations. This paper presents a study of the stator winding insulation system of a decommissioned 11kV motor with the removed rotor, using offline PD measurement. The measurement results revealed PD signals in all three phases. The PRPD patterns indicate internal delamination discharge and discharge at stress control coating(S/C) and stress control grading which is occurring simultaneously. When the test voltage is increased to a certain point, the electric field stress in the stress control grading area becomes high enough to cause a gap-type discharge pattern, occurring between the press finger and the stress control grading area. Visual inspections also revealed spark discharge.
Some of the metrics are blocked by your
consent settings
Localisation of Partial Discharge in Power Cables Through Multi-Output Convolutional Recurrent Neural Network and Feature Extraction
(2023-02-01)
Yeo, Joel
;
Jin, Huifei
;
Mor, Armando Rodrigo
;
Yuen, Chau
;
Pattanadech, Norasage
This paper proposes an algorithmic approach constructed from a convolutional recurrent neural network (CRNN) iterated with examination of extracted features for partial discharge (PD) localisation; tests were conducted offline on medium voltage (MV) power cables. To evaluate the performance of the algorithm, a case study was performed on 7 cables deliberately selected to comprehensively illustrate the difficulties encountered in field testing. The experimental test results prove that the proposed concept is able to identify and localise discharges besmirched with significant quantities of noise. Main contribution of the methodology is the successful automated interpretation of measurements acquired under noisy challenging field constraints.
Some of the metrics are blocked by your
consent settings
Online PD Measurement by Detecting the Pulsed Compensating Current in High Voltage Equipment
(2022-01-01)
Srinangyam, Chissanupong
;
Pannil, Pittaya
;
Nimsanong, Phethai
;
Chuayin, Chaitawat
;
Thungsook, Kittisak
This paper discusses the pulsed compensating current caused by partial discharge (PD) phenomena that flows inside the electrical equipment installed in the power system. Such electrical equipment like to be the capacitive coupler in the partial discharge test circuit. In order to study the pulsed compensating current of the PD measurement, artificial PD source such as corona, surface, and internal was used in this experiment. The electrical equipment like surge arrester combined with HFCT sensor utilized to detect the PD pulse current. Furthermore, this proposed technique has been applied for online PD measurement in substations. It was found that the surge arrester could compensate for the pulse current arising from the PD source. This study will be helpful information for online PD measurement.
Some of the metrics are blocked by your
consent settings
Partial discharge characteristics of mineral oil immersed transformer compared with natural ester and palm oil immersed transformer under different periods of impregnation
(2020-09-13)
Maneerot, Sakda
;
Pattanadech, Norasage
This paper represents the partial discharge (PD) characteristics of mineral oil immersed transformer compared with natural ester, and palm oil immersed transformer under different periods of impregnation. Three identical three-phase transformers with 22kV/400V 50 kVA rated were designed and constructed. The first transformer was fully filled with mineral oil. The second transformer was fully filled with natural ester (FR3), and the third transformer was fully filled with palm oil. The partial discharge at 1.1Urated of these transformers with various conditions, i.e., non-impregnated paper, impregnated paper with 3 hours, and 6 hours was investigated. The impregnation process was done with 65 <sup>o</sup>C liquid temperature and 5 mmbar pressure. From the test results, it can be concluded that PD characteristics of the mineral oil immersed transformer was obviously different compared with these of the natural oil (FR3) immersed transformer and the palm oil immersed transformer. Moreover, the impregnation impacted PD characteristics of the tested transformers, which were analyzed and reported in this paper.
Some of the metrics are blocked by your
consent settings
Experiences in nonconventional partial discharge measurement for gas-insulated substation in Thailand
(2020-01-01)
Nganpitak, Tritod
;
Kunakorn, Anantawat
;
Klienhom, Sitthisak
;
Likhitsupin, Suwapich
;
Jariyawichai, Parinya
Nowadays, nonconventional partial discharge (PD) measurement has become essential for diagnosis the high-voltage insulation condition. The nonconventional PD measurement not only uses for periodic assessment but also uses for commissioning test after transportation and installation. This paper focuses on nonconventional PD test techniques using Ultra-high frequency (UHF) sensors, acoustic sensors and light detection sensors for gas-insulated substation (GIS) commissioning test. Fundamental defects found in GIS: (1) Hopping particles (2) Fixed protrusions (3) Floating potential and (4) Voids are described. Then, explanation about how to detect such defects by using UHF, acoustic and optical methods. Afterwards, PD commissioning tests were performed with three 230 kV electricity generating authority Thailand (EGAT) GISs, i.e., Phayao EGAT GIS, Lamphun 2 EGAT GIS and North Bangkok EGAT GIS. The PD signals due to hopping particle were found by using UHF sensors at Phayao and North Bangkok EGAT GISs. The acoustic PD test technique was used in Phayao EGAT GIS to locate such particles. In case of Lamphun 2 EGAT GIS, by using UHF measurement, PD signals were found due to tracking caused by flashover on the cone insulation surface. Later, light detection sensors were used to detect the PD location. As a result of studies, its clearly guarantee the powerful accuracy and efficiency of nonconventional PD measurement by the combination of UHF and acoustic technique including light detection sensors.
Some of the metrics are blocked by your
consent settings
The study of conventional partial discharge measurement for gas insulated line
(2019-07-01)
Pattanadech, Norasage
;
Houngtaisong, Chakkri
;
Wichakul, Chalantorn
;
Thanormsakdomrong, Narinnitiporn
;
Monklang, Natthanon
Partial discharge (PD) measurement is one of the insulation diagnosis tools used for diagnosis the condition of the high voltage apparatus. Generally, PD is generated at the highly electric field stress site in the insulation system. This research focuses on PD measurement in a gas-insulated line (GIL) by using the conventional PD measurement. The 230kV, 2500A, single phase, GIL with 2.5m length was setup and used for experiments. In this paper, the experiments were divided into 4 cases, according to the types of artificial protrusions, i.e. 1) a protrusion on the high voltage conductor 2) a protrusion on the enclosure and 3) two protrusions on both conductor and enclosure. 4) a protrusion on the conductor covered by insulation compartment. The lengths of protrusions were varied. The results of experiment were presented with the phase resolved partial discharge patterns.
Some of the metrics are blocked by your
consent settings
Applying HF and VHF/UHF partial discharge detection for distribution transformer
(2019-01-01)
Maneerot, Sakda
;
Kando, Masaaki
;
Pattanadech, Norasage
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<sup>◦</sup>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.
Some of the metrics are blocked by your
consent settings
Comments on PDIV testing procedure according to IEC 61294
(2017-11-29)
Pattanadech, Norasage
;
Muhr, Michael
—In this paper, partial discharge inception voltage (PDIV) and partial discharge (PD) activity of mineral oil with water content of 4 ppm are investigated. The PDIV test procedure was performed according to IEC 61294. Then, the PDactivitywas recorded for 1 minute at 1.1 PDIV level. The investigation wasconducted with a needle – plane electrode and a needle –sphere electrode by which different tip radius needles, plane electrodes, and various diameter sphere electrodes were used for the experiments. The PDIV and PD activity test results are reported in this paper. It was found that PDIV strongly depends on the electrode configuration and the gap distance. From the experiments,PDIV values of some electrode systems were not obtained due to the problems of breakdown events occurring during the experiments.Theparticular patterns for PDIV testing to explain the possibility PD and breakdown events which may occur during PDIV testing in accordance with IEC 61294 are developed. The particular patterns for PDIV testingare divided into four cases as the followings: The first PD pulse coexisting with PDIV, the low risk of breakdown for PDIV experiment, the medium risk of breakdown for PDIV experiment and the high risk of breakdown for PDIV experiment. In case of the very simple case PDIV and the lower risk of breakdown for PDIV experiment, the PDIV can be detected without breakdown occur. However, in the case of the medium risk of breakdown for PDIV experiment breakdown may take place before or after the PDIV is detected. In the case of high risk of breakdown for PDIV measurement, breakdown takes place easily during performing the PDIV experiment.Therefore, the exact PDIV valuesare not be obtained for such cases. To avoid the breakdown events which may occur during PDIV experimentaccording to IEC 61294 was performed, the combined PDIV measurement was recommended. Besides, PDIV testing with the combined PDIV method provided the lower PDIVwhich was closer to the theoretical PDIV compared with testing in accordance with IEC61294.
Some of the metrics are blocked by your
consent settings
The study of disc monopole antenna for partial discharge measurement
(2007-12-01)
Petchphung, Prawit
;
Leelajindakrairerk, Monthon
;
Pattanadech, Norasage
;
Yutthagowith, Pearawut
;
Aunchaleevarapan, Kraision
This paper presents the study of disc monopole antenna for partial discharge measurement. The antenna was studied with computer program and tested. Then it was used for partial discharge measurement of the artificial partial discharge models, corona discharge, surface discharge, and internal discharge. The partial discharge tested results obtained from the designed antenna are relatively similar the tested results obtained from the standard antenna. The tested results show that the designed disc monopole antenna prototype has the good characteristics to measure partial discharge phenomena. It is still improving for high efficiency. © 2007 RPS.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results