Faulty Line Selection Method Based on Comprehensive Dynamic Time Warping Distance in a Flexible Grounding System

A flexible grounding system is a system in which the neutral point of the power supply is grounded via the arc suppression coil in parallel with a low-resistance resistor. When operating normally or a temporary ground fault occurs, the arc suppression coil is used for grounding, whereas the small resistance is switched on when a permanent ground fault occurs. At present, the problem of low protection sensitivity when a high-resistance ground fault occurs in a flexible grounding system has not been solved yet. According to the characteristics of low waveform similarity between the faulty line and the non-faulty line when a single-phase grounding fault occurred, a new faulty line selection method based on a combination of Dynamic Time Warping (DTW) distance and the transient projection method is proposed in this paper. Firstly, the fault transient signal is extracted by a digital filter as a basis for faulty line selection. Secondly, the transient zero-sequence current of each line is projected onto the busbar transient zero-sequence voltage, and the projected DTW distance of each line is calculated. Finally, according to the calculation formula of waveform comprehensive similarity coefficient, the Comprehensive DTW (CDTW) distance is obtained, and the top three CDTW distance values are selected to determine the faulty line. If the maximum value is greater than the sum of the other two CDTW distance values, the line corresponding to the maximum value is judged as the faulty line; otherwise, it is judged as a busbar fault. The simulation results based on MATLAB/Simulink and field data test show that the method can accurately determine the faulty line under diverse fault conditions.

Physical and Nutritional Properties of Local Hawm Gra Dang Ngah Rice Varieties

Information on the local rice varieties grown in each Tambon (subdistrict), community or part of Thailand is still outdated. The present pilot work aimed to determine physical characteristics (grain dimensions, 1000-grain weight and color parameters) of paddy and dehusked rice in order to enhance the nutritional quality of these varieties. Moreover, it further supports cultivation of local Hawm Gra Dang Ngah (HGDN) rice in Narathiwat to ultimately develop to commercial premium quality. The nutritional values of dehusked rice were also compared among Tambons, as well as between the dehusked rice of local HGDN versus pure line selection HGDN PTNC09002-59. The study analysed rice samples grown locally in 4 Tambons: Bangkhunthong, Phron, Praiwan and Salamai in Takbai Amphoe (district), Narathiwat, Thailand. The main findings in this study revealed that medium and long types of both paddy and dehusked rice were all found in each Tambon. Moreover, local dehusked HGDN grain was darker red-brown color. All Tambons were found to contain comparable nutrient levels. High levels of dietary fiber were detected in all Tambons. Overall, the dehusked HGDN rice grown in Bangkhunthong showed the highest levels of vitamin B2 and calcium. The dehusked HGDN (100 g/dry weight) in Bangkhunthong, Phron, Praiwan and Salamai contains protein; 8.73±0.01, 7.65±0.00, 8.22±0.03 and 6.83±0.03, iron; 8.73±0.01, 7.65±0.00, 8.22±0.03 and 6.83±0.03, ash; 1.19±0.00, 0.75±0.00, 1.10±0.00 and 1.34±0.00. These findings provide new information about local HGDN, and may be utilized to support the agricultural community in Takbai, enabling the selection of optimal HGDN varieties for local commercial use, as well as in breeding programs, to facilitate the promotion of local HGDN in the national Thai rice market.

Comparison of Phototoxicity Sensitivity by the Neutral Red Uptake Method for BALB/c 3T3, HaCaT, and HDFa Cells In Vitro

ABSTRACT Introduction Phototoxicity is an acute photoinduced reaction. The 3T3 neutral red uptake (NRU) phototoxicity test has high sensitivity for the determination of phototoxic substances. To further optimize the method, this study mainly focused on comparing the phototoxicity sensitivity by using the NRU method for BALB/c 3T3, HaCaT, and HDFa cells in vitro. Methods The NRU method was used to evaluate the phototoxicity of chlorpromazine hydrochloride (CPZ), amiodarone hydrochloride (Amiodar), and L-histidine (L-His) on BALB/c 3T3 cells, HaCaT cells, and HDFa cells. The sensitivity of different cells to ultraviolet (UVA) irradiation in vitro was studied. Results L-His showed no phototoxicity, but the phototoxicity of CPZ and Amiodar showed different sensitivities among the three kinds of cells. The in vitro phototoxicity evaluation of HaCaT cells is closer to that of primary human fibroblasts. Conclusion This study provides a reference for cell line selection to optimize the existing in vitro evaluation method of 3T3 NRU phototoxicity.

Performance test of small-current grounding line selection device based on the real-time digital simulation system

Single phase grounding fault is the most common fault type in small-current grounding distribution network, but the small-current grounding line selection device put into operation on site is often difficult to meet the application requirements, affecting the rapid and accurate treatment of grounding fault. Considering that there are many small-current grounding line selection manufacturers and various device forms, it is difficult to intuitively evaluate the line selection performance of different devices and make horizontal comparison, and there is no supporting basis for the selection and application of on-site line selection devices. Therefore, based on the real-time digital simulation system (RTDS), this paper establishes a test platform for small-current grounding line selection device. Based on the constructed test platform, four line selection devices form different manufacturers are tested in parallel, the performance of the devices is compared, and the influencing factors affecting the accuracy of line selection results are analyzed. The conclusions of this paper can provide strong support for the pilot application of small-current line selection devices.

Fault Line Selection Method Based on Transfer Learning Depthwise Separable Convolutional Neural Network

With the continuous development of artificial intelligence technology, the value of massive power data has been widely considered. Aiming at the problem of single-phase-to-ground fault line selection in resonant grounding system, a fault line selection method based on transfer learning depthwise separable convolutional neural network (DSCNN) is proposed. The proposed method uses two pixel-level image fusions to transform the three-phase current of each feeder into the RGB color image, which is used as the input of DSCNN. After DSCNN self-feature extraction, the fault line selection is completed. With the consideration that not all of power distribution systems can obtain a large amount of data in practical applications, the transfer learning strategy is adopted to transplant the trained line selection model. The smaller number of DSCNN parameters increases the portability of the model. The test results show that not only does the proposed method extracts obvious features, but also the line selection accuracy can reach 99.76%. It also has good adaptability under different sampling frequencies, different noise environments, and different distribution network topologies; the line selection accuracy can reach more than 97.43%.