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A novel algorithm based on the correlation analysis of waveforms to distinguish between the magnetizing inrush and the short-circuit fault current is proposed. The algorithm makes use of the characteristics of differential current waveform in the nonsaturation zone that it is similar to a part of the sinusoidal wave under the short-circuit fault and far different with the sinusoid under the inrush condition. To realize this algorithm, the nonsaturation zone of the transformer is decided by comparing the algebraic sum of sampling data in a short slide window of the differential current under the magnetizing inrush or the short-circuit fault, then two kinds of normal sinusoidal waveforms are structured according to the value and position of the peak point of differential current in the nonsaturation zone. The correlation coefficients between the original waveform and two structured sinusoidal waveforms are calculated, and the magnetizing inrush or fault current is judged according to the average of two correlation coefficients. The experimental results verify that the algorithm can correctly open the differential protection shortly for the internal short-circuit fault in operation, energized with a turn-to-turn short-circuit fault, reliably blocking the protection during the magnetizing inrush, and obtaining good immunity to the saturation of the current transformer. Low computation and requirements contributing to this algorithm are performed in practice. Index Terms--Correlation analysis, fault current, magnetizing inrush, nonsaturation zone, transformer.

Objective To test the efficacy of locally produced Vi vaccine over a time period of longer than one year. Methods A double-blinded, randomized field trial was performed in Guangxi Zhuang Autonomous Region in south-western China, using 30 [micro]g doses of locally produced Vi. Enrolled subjects were 3-50 years of age, although the majority (92%) were school-aged children, who have the highest rate of typhoid fever in this setting. A total of 131 271 people were systematically allocated a single dose of 30 [micro]g of Vi polysaccharide or saline placebo. The study population was followed for 19 months, with passive surveillance conducted in the Ministry of Health and the Regional Health and Anti-epidemic Centre (HAEC). Clinically suspected cases of typhoid fever were confirmed by blood culture, or by serological reaction with O-antigen (Widal tests). Findings After 19 months, there were 23 culture-confirmed cases of typhoid fever in the placebo group versus 7 cases in the Vi group (Protective efficacy (PE) = 69%; 95% CI = 28%, 87%). Most of the isolates were from school-aged children: 22 cases in the placebo group versus 6 in the Vi group (PE = 72%; 95% CI = 32%, 82%). No serious post-injection reactions we,re observed. The locally produced Vi polysaccharide vaccine showed levels of protective efficacy similar to those for Vi vaccine produced in industrial countries. Conclusion The slightly higher dose of vaccine did not seem to alter efficacy significantly in China. Keyword Typhoid-paratyphoid vaccines/administration and dosage; Polysaccharides, Bacterial/immunology; Typhoid fever/immunology; Placebos; Clinical trials, Phase II; China (source: MESH). Mots cles Vaccin antityphoparatyphoidique/administration et posologie; Polyosides bacteriens/immunologie; Fievre typhoide/immunologie; Placebo; Essai clinique phase II; Chine (source: INSERM). Palabras clave Vacunas tifoide-paratifoide/administracion y dosificacion; Polisacaridos bacterianos/inmunologia; Fiebre tifoidea//inmunologia; Placebos; Ensayos clinicos fase II; China (fuente: BIREME). Bulletin of the World Health Organization, 2001, 79: 625-631., Voir page 630 le resume en francais. En la pagina 630 figura un resumen en espanol. Introduction Typhoid fever is still an endemic infectious disease in some rural areas of [...]