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Pulse-Sequence Analysis of Discharges in Air, Liquid and Solid Insulating Materials
Suwarno,Teruyoshi. Mizutani 대한전기학회 2006 Journal of Electrical Engineering & Technology Vol.1 No.4
Electrical discharges may occur in gas, liquid as well as solid insulating materials. This paper describes the investigation results on the discharges in air, silicone oil and low density polyethylene (LDPE) using needle plane electrode system under AC voltage of 50 ㎐. The experimental results showed that for discharge in air (corona), discharge pulses were concentrated around the peak of applied voltage at negative half cycle. For silicone oil positive as well as negative discharges were observed which concentrated around the peak of applied voltage. The positive pulse number was smaller but the magnitude was higher than that of negative discharge. Discharges in void took place at wider range of phase of applied voltage. The unbalance in pulse number and magnitude similar to that of oil discharges were observed. For electrical treeing in LDPE, the discharges were spread before the zero cross of the applied voltage up to the peak at both positive and negative half cycles. The discharge pulse sequence analysis indicated that the PD occurrence in air , oil and void were strongly affected by the magnitude of applied voltage. However, for electrical treeing it was observed that the discharge occurrence was strongly affected by the time derivative of the applied voltage (dv/dt).
Suwarno 대한전기학회 2006 Journal of Electrical Engineering & Technology Vol.1 No.1
This paper reports the investigation results on the leakage currents (LC) on polymeric outdoor insulators. The samples used were EPDM (ethylene prophylene diene monomer) insulators used at 20 ㎸ distribution lines. AC voltage was applied and the LC waveforms were measured under various environmental conditions (humidity and pollution). Digital data of the LC was transferred from a digital storage oscilloscope to a computer for further analysis. The LC waveform parameters such as magnitude and harmonic content (as indicated by the total harmonic distortion (THD)) were analyzed. The experimental results showed that 3rd, 5th and 7th harmonics and higher odd harmonics were observed for symmetrical-distorted LC waveforms while for unsymmetrical-distorted LC waveforms, odd and even harmonics were observed. The LC analysis indicated that there are 5 stages of insulator conditions from normal condition up to flashover correlated with different kind of LC waveforms. The results also showed that in general the magnitude of LC was good enough to show the condition of the insulators. However, under discharge condition (for example as a result of dry band arching) the LC magnitude should be combined by the THD to show a better correlation with the insulator condition. The product between THD and LC magnitude may be used as a diagnostic parameter.
Suwarno Suwarno The Korean Institute of Electrical Engineers 2006 Journal of Electrical Engineering & Technology Vol.1 No.1
This paper reports the investigation results on the leakage currents (LC) on polymeric outdoor insulators. The samples used were EPDM (ethylene prophylene diene monomer) insulators used at 20 kV distribution lines. AC voltage was applied and the LC waveforms were measured under various environmental conditions (humidity and pollution). Digital data of the LC was transferred from a digital storage oscilloscope to a computer for further analysis. The LC waveform parameters such as magnitude and harmonic content (as indicated by the total harmonic distortion (THD)) were analyzed. The experimental results showed that 3rd, 5th and 7th harmonics and higher odd harmonics were observed for symmetrical-distorted LC waveforms while for unsymmetrical-distorted LC waveforms, odd and even harmonics were observed. The LC analysis indicated that there are 5 stages of insulator conditions from normal condition up to flashover correlated with different kind of LC waveforms. The results also showed that in general the magnitude of LC was good enough to show the condition of the insulators. However, under discharge condition (for example as a result of dry band arching) the LC magnitude should be combined by the THD to show a better correlation with the insulator condition. The product between THD and LC magnitude may be used as a diagnostic parameter.
Yudhistira Nugraha,Sintho Wahyuning Ardie,Munif Ghulammahdi,Suwarno,Hajrial Aswidinnoor 한국작물학회 2016 Journal of crop science and biotechnology Vol.19 No.1
The breeding for iron toxicity tolerant rice needs an effective, efficient, and reliable screening method. The study was aimed to evaluate the best method for screening iron tolerant genotypes at the seedling stage in the greenhouse. Two rice genotypes, Mahsuri (tolerant) and IR64 (sensitive) were grown in three modified media solutions namely, Yoshida-conventional solution (YCS), Yoshida with etylenediamintetraacetic acid (1:2) (YES), and Yoshida with 0.2% agar (YAS). Three levels of iron were tested to observe the severity of their leaf bronzing score (LBS). The optimized solution in the greenhouse was then evaluated using 24 rice genotypes. Using the same genotypes interrelationship, the LBS in the greenhouse with grain yield and its attributes was validated under acute and moderate Fe toxicity in the field. The results showed that the optimized media culture was YAS with 400 mg L-1 of FeSO4. This media had more stable pH and redox potential, it could maintain sufficient Fe2+ supply over 10 days, and it could discriminate of LBS between tolerant and sensitive genotypes. Evaluation using the optimized media solution showed that there was a significant variation among genotypes in shoot dry weight and a significant correlation of relative reduction of shoot dry weight with LBS. The LBS in the greenhouse was correlated with LBS in acute iron stress in the field (r=0.673**) and the grain yield (r= -0.618**). This study has proven that YAS culture media can be used as early identification of iron toxicity tolerant genotypes for supporting breeding programs.
Development of High-Yielding Rice Varieties Suitable for Swampy Lands in Indonesia
( Indrastuti A. Rumanti ),( Yudhistira Nugraha ),( Rina H. Wening ),( Zennia Jean C. Gonzaga ),( Suwarno ),( Anggiani Nasution ),( Dede Kusdiaman ),( Endang M. Septiningsih ) 한국육종학회 2016 Plant Breeding and Biotechnology Vol.4 No.4
Productivity of swampy land rice varieties in Indonesia remains low due to abiotic and biotic stresses. Iron toxicity, submergence and long-term flooding are common problems that affect plant growth, sometimes leading to total crop loss. Meanwhile, rice blast, rice tungro virus (RTV), and bacterial leaf blight (BLB) can also lead to severe yield loss. These stresses could be overcome by an integrative approach of cultural practices and planting multi-stress tolerant rice. Here we describe the development of new high-yielding varieties that are adapted to the swampy land environments in Indonesia with multi-stress tolerance to diverse abiotic and biotic stresses. Multi-environmental trials were performed in nine locations to screen for several abiotic and biotic stresses in the field and greenhouse in 2012 and 2013. This study identified promising rice lines that had high grain yield as well as tolerance to iron toxicity and submergence, resistance to BLB and RTV, and good grain quality. The best line was B11377F-MR-34-2, derived from a double cross among Cinglonik, IRBB7, Mamberamo and IR64. It was confirmed that this advanced breeding line carries the submergence tolerance gene, SUB1, through expression analysis of the SUB1A gene. Another promising line was B11586F-MR-11-2-2, having iron toxicity tolerance, resistance to RTV, and high milling recovery. Moreover, these lines have passed the Indonesian national variety release committee and have been named as Inpara8 and Inpara9, and are targeted for dissemination and adoption in the swampy areas.