Pattanadech, Norasage

Preferred name

Alternative Name

Pattanadech, N.

Main Affiliation

School of Engineering

norasage.pa@kmitl.ac.th

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Dielectric analysis of degraded stator bars of a hydro generator
(2022-04-01)
Pattanadech, Norasage
;
Phumipunepon, Natnaree
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Srinangyam, Chissanupong
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Jeenmuang, Siwakorn
;
Bunlaksananusorn, Chanin
This paper presents the investigation of dielectric analysis of degraded stator bars by Polarization and Depolarization Current (PDC) measurement. The stator bars obtained from the 30-year in-service synchronous machine were divided into two groups. The first group was the unmodified stator bars. The second group was the simulated degradation stator bars which were composed of the thermal stress stator bars, conductive tap abrasion stator bars, multiple air cavity stator bars, multiple oil filled stator bars and multiple water filled stator bars. PDC test experiment was performed with the stator bar samples. PDC test results were analyzed in time domain and in frequency domain with the derived parameters i.e. R<inf>dc</inf>, real and imaginary part of complex capacitance, C ratio, conduction loss factor and polarization loss factor. It was found that PDC shapes obtained from the conductive tape abrasion stator bar and multiple water filled cavity stator bar were clearly different from that of the unmodified stator bar. For other case studies, the derived parameters showed the usefulness in analysis the degraded stator bar characteristics. For example, the increase in the imaginary capacitance and conduction loss factor can be observed from most cases of degraded stator bar test results.
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Localisation of Partial Discharge in Power Cables Through Multi-Output Convolutional Recurrent Neural Network and Feature Extraction
(2023-02-01)
Yeo, Joel
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Jin, Huifei
;
Mor, Armando Rodrigo
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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.
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THE INFLUENCE of NANOPARTICLES on the DIELECTRIC DISSIPATION FACTOR and LIGHTNING PROPERTIES in PALM OIL-BASED NANOFLUIDS
(2022-04-01)
Pattanadech, Norasage
;
Muangpratoom, Pichai
In this study, the influence of nanoparticles when mixed with insulating palm oil is investigated in terms of tan δ or the dielectric dissipation factor and lightning properties. Three different nanofluid sample types are derived from the dispersion of zinc oxide (ZnO), titanium dioxide (TiO2) and barium titanate (BaTiO3). The nanoparticle concentrations tested were 0.01% and 0.03% while the base fluid was unmodified palm oil. Evaluation of tan δ was performed in accordance with the IEC 60247 standard via the use of the tan δ meter (model SOKEN: DAC-IM-D6) and the lightning impulse breakdown voltage were based on the IEC 60897 standard. In order to test the electrical insulation qualities of the palm oil over a range of temperatures from 35-90°C for each of the tan δ values revealed the dielectric loss tangent, and the findings lightning properties was performed at the room temperature. Significant increases of the palm oil with nanoparticles in comparison to unmodified palm oil. These results suggested that further investigation would be worthwhile to better understand the effects of the nanoparticles in palm oil upon tan δ and the lightning impulse breakdown voltage characteristics in order to make additional improvements.
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Improved Least-Square Prony Analysis Technique for Parameter Evaluation of Lightning ImpulseVoltage and Current
(2016-02-01)
Yutthagowith, P.
;
Pattanadech, N.
This paper represents a fast curve-fitting technique for evaluation of either lightning impulse voltage or the current base curve. The technique based on least-square Prony analysis employs the double integration of the recorded waveform for waveform evaluation. The undesirable effect of noise exiting in Prony analysis technique is mitigated. The base curve formula is written in the complex form of the double exponential function. A decomposition technique is utilized for determination of the base curves of full lightning impulse voltages with oscillations and of lightning impulse currents. To verify the performance of the proposed method, the base curves reconstituted from the developed method were compared with the curves reconstructed from a nonlinear least-square regression prescribed in the standard. The execution time of the proposed method is much shorter than that of the conventional method because it does not need the iteration process. With noise immunity characteristics and avoidance of recorded waveform distortion, the results from the proposed technique based on the normal implementation are remarkably accurate. The results of this study indicated that the proposed method is the powerful one to apply for lightning impulse voltage and current base curve evaluation.
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The investigation of insulation performance evaluation of the large electrical rotating machine in frequency domain
(2019-01-01)
Phloymuk, Natthawut
;
Kando, Masaaki
;
Pattanadech, Norasage
The insulation structure of winding in a large electrical rotating machine consists of epoxy resin and mica material. The insulation structure is composed of many junctions. The insulation problems generate different kinds of signals, such as electromagnetic waves, which may get released from the non-perfect characteristics of the enclosure. This signal may interfere with the functioning of other nearby electronic devices. Therefore, maintaining an excellent condition of the insulation system of the machine is very important. For a condition monitoring of this insulation as proposed in this research, it is taken into consideration the results of the polarization and depolarization current (PDC) measurement of the test sample, and the stator winding rated 13.8 kV was investigated. The experiments were conducted under different thermal stresses, i.e., 25<sup>◦</sup>C (the room temperature) and 100<sup>◦</sup>C (the operation temperature). The test samples were divided into three types: I. haft-overhang, II. overhang and III. full stator bar. From the PDC measurement data record, the complex capacitance and polarization losses (ion migration polarization, slow relaxation polarization and interfacial polarization) were calculated. It was found that the aging of the insulation related to the complex capacitance and polarization losses can be contributed for research in future wireless technology.
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Partial discharge inception voltage investigation of mineral oil: Effect of electrode configurations and oil conditions
(2016-10-01)
Pattanadech, N.
;
Muhr, M.
The aim of this paper is to describe the Partial Discharge Inception Voltage (PDIV) and Partial Discharge (PD) characteristic of mineral oil tested by various electrode configurations. Furthermore, mineral oil with different conditions was investigated under AC voltage. The PDIV and PD of the mineral oil, Nynas Nytro 4000x, with water content about 4 ppm was investigated by using various electrode configurations of needle - plane and needle - sphere electrodes under room temperature. The PDIV test circuit was set up according to IEC 60270. Then, two PDIV measurements were applied for the investigation. The first PDIV test procedure (IEC method) was performed in accordance with IEC 61294. The second PDIV test procedure so-called combined PDIV method was adapted from IEC standard. Moreover, the electric field distributions of the electrode systems were also calculated. According to the test results, PDIV depended clearly on the electric field stress of the electrode system and the test method. Compared with other electrode configurations, the 10 μm tip radius needle - 75 mm dia. plane electrode gave the highest electric field stress and inversely provided the lowest PDIV value tested by both test methods. The combined PDIV test method generated the PDIV, charge quantity, and charge repetition significantly lower than measuring by IEC method. To investigate the effect of oil conditions on PDIV and PD characteristics, the combined conditions of temperature and water content of the mineral oil were controlled as the parameters for investigation. It was found that the water content in the mineral oil influenced approximately on PDIV value when the oil temperature was at room temperature. However, at the oil temperature of 40-90 °C, the PDIV values of the mineral oil with water content 4, 20 and 40 ppm were relatively the same. From the PD pulse current test results, PD pulse current recorded at the PDIV value from both test methods was about 0.15-1.3 mA. Pulse duration was in the range of 0.7-9 μs and the rise time was between 40-570 ns.
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The State of Health Estimation of Retired Lithium-Ion Batteries Using a Multi-Input Metabolic Gated Recurrent Unit
(2025-03-01)
He, Yu
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Pattanadech, Norasage
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Sukemoke, Kasiean
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Pan, Minling
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Chen, Lin
With the increasing adoption of lithium-ion batteries in energy storage systems, accurately monitoring the State of Health (SoH) of retired batteries has become a pivotal technology for ensuring their safe utilization and maximizing their economic value. In response to this need, this paper presents a highly efficient estimation model based on the multi-input metabolic gated recurrent unit (MM-GRU). The model leverages constant-current charging time, charging current area, and the 1800 s voltage drop as input features and dynamically updates these features through a metabolic mechanism. It requires only four cycles of historical data to reliably predict the SoH of subsequent cycles. Experimental validation conducted on retired Samsung and Panasonic battery cells and packs under constant-current and dynamic operating conditions demonstrates that the MM-GRU model effectively tracks SoH degradation trajectories, achieving a root mean square error of less than 1.2% and a mean absolute error of less than 1%. Compared to traditional machine learning algorithms such as SVM, BPNN, and GRU, the MM-GRU model delivers superior estimation accuracy and generalization performance. The findings suggest that the MM-GRU model not only significantly enhances the breadth and precision of SoH monitoring for retired batteries but also offers robust technical support for their safe deployment and asset optimization in energy storage systems.
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Power transformer fault warning combining support vector machine and improved grey wolf optimization algorithm
(2025-01-01)
Zhao, Shuzong
;
Pattanadech, Norasage
To optimize the parameter setting of the support vector machine and improve the classification performance and computational efficiency of power transformer fault diagnosis, this study proposes an improved grey wolf optimization algorithm. By optimizing the global search and local optimization capabilities of the grey wolf algorithm and combining them with stacked denoising autoencoders, a new power transformer fault warning model is constructed. Firstly, the grey wolf optimization algorithm is optimized through four strategies: elite reverse learning, nonlinear control parameters, Lévy flight, and particle swarm optimization, which improve its global search and local optimization capabilities. Secondly, the stacked denoising autoencoder is utilized to extract high-level features of fault data, and the improved GWO algorithm and SVM are combined to complete fault classification. The results indicated that the proposed diagnostic model achieved a diagnostic accuracy of 0.979, a recall rate of 0.986, and an F1 value of 0.983 in benchmark performance testing. In practical applications, the average fault diagnosis accuracy of this model could reach up to 99.21%, and the average diagnosis time was only 0.08 s. The developed power transformer fault warning model can provide an efficient and reliable technical solution for fault diagnosis in the power system.
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Study of Problem and Effect Mitigation Technique of Unbalance Capacitance in 500 kV Single Phase Transformers
(2024-01-01)
Suksagoolpanya, Suthat
;
Pattanadech, Norasage
This article presents the study of the effect of unbalanced stray capacitance in single-phase 500 kV power transformers and establishes the mitigation technique. The power transformers were operated in Wang Noi Substation for transmitting the electrical power. There are 3 units of single-phase power transformer. Previously, a transformer of phase B failed after being serviced for several years. Thus, the new power transformer was ordered instead of the failed one. However, once the new system had been operated, the hotspots at the surge arrester of tertiary winding (22 kV) were found and the unbalance of phase voltages was observed, resulting in overvoltage as a root cause of the problem. Once a thorough investigation was done, it was found that there was an effect of unbalanced stray capacitance between tertiary winding and ground core since the new power transformer has some different designs compared with the remaining. Hence, the mitigation technique was performed by adding the capacitor parallel to the tertiary winding until the voltage balance was achieved. Simulation with the PSCAD program was performed to determine the optimum value for additional capacitors, i.e., voltage balance, using an iterative method. In this article, the capacitors used for additional were capacitor voltage transformers, which have been installed. As a result of the troubleshooting, the voltage at the 22 kV bus was more balanced as well as not causing overvoltage, and the hotspots at the surge arrester of tertiary winding were not detected resulting in gaining the stability and reliability of using these transformers.
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VLF dielectric response and HF localized dielectric discharge measurement for rotating machine insulation assessment
(2020-08-14)
Nimsanong, P.
;
Pattanadech, N.
This paper represents the very low frequency (VLF) dielectric response and high frequency (HF) localized dielectric discharge measurement for rotating machine insulation assessment. The integral conditions of stator winding insulation, the so-called aging condition, were investigated by the dielectric response measuring technique. The polarization and depolarization currents in the VLF range from 0.0001 to 1 Hz were measured under an external step electric field. The local conditions of stator winding insulation, the so-called weak spot condition, were examined by the partial discharge (PD) measuring technique. The PD pulse currents were detected by a capacitive sensor in a wide-band range, where the bandwidth of the measuring system was set between 30 kHz and 30 MHz. The medium voltage rotating machine rated 6.6 kV and 240 to 2,270 kW under different service conditions, i.e., new stator winding, moisture contamination, dirt contamination as well as thermally and severely aged insulation, was studied. Besides, four case studies on measuring the PD in service rotating machines rated 11–15 kV, 7100 to 211,000 kW as well as the attenuation of the PD pulses were conducted and demonstrated. With several case studies, this paper introduces new dielectric parameters, the so-called charge ratio (QR) and charge difference gradient (QDG), to identify the dielectric mechanism occurring in the stator winding insulation caused by the polarization and conduction processes. It can be concluded that the proposed parameters are a valuable tool for assessing the aging condition. In the case of the PD measurement, it was found that the PD pulse is strongly attenuated in the slot section. This paper also introduces the combination of both the dielectric response and PD measurement results, which can be very useful for assessing a complete insulation condition in the rotating machine. Moreover, the criteria for insulation conditions are suggested in this paper to evaluate the integral and local conditions for the rotating machine insulation. The local discharge in the machine causes electromagnetic waves, which may get released from the non-perfect characteristics of the enclosure. This signal may interfere with the functioning of other nearby electronic devices, especially the communication equipment. Therefore, maintaining the excellent condition of the insulation system by the proposed technique detailed in this paper will support the highly effective operational efficiency of the communication system as well.

Pattanadech, Norasage

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