电压型电机断相检测电路的研究

介绍了一种电压型电机断相检测电路，对断相时人工中性点对地的偏移电压作了谐波分析，指出采用双T滤波器是消除谐波干扰、避免断相保护装置误动作的有效方法。

超高压变压器断相保护研究

2021年12月26日,某750 kV变电站变压器C相高压侧套管内部载流连接件发生断裂,套管上节发生位移,由于在低负荷工况下现有变压器保护对断相故障无法判别,导致现场变压器长时间断相运行,套管会有随时掉落的风险,可能造成变压器内部爆燃、绝缘击穿、绕组变形等永久性损伤。为应对轻载工况的断相故障对变压器安全运行的威胁,提出基于测量级电流互感器的变压器断相保护方案,通过检测变压器高压侧电流、电压及低压侧套管电流,有效鉴别出变压器轻载工况下的断相故障,解决变压器保护对断相故障检测不灵敏、隔离不及时的问题,保障电网安全稳定运行。

8051最小系统在高层建筑供水塔自动控制系统中的运用

给出一种使用单片机控制水塔水位系统 ,阐述了 MCS- 5 1的控制水位原理、过程、硬件设置、软件设计。

Detection and Analysis of an Estrous－associated Oviductal Glycoprotein DNA Fragment from Primates by PCR

DNA was extracted from lymphocytes of primates and PCR was used to amplify the estrous-associated glycoprotein DNA fragment. 537 kb DNA fragments from crab eating macaque were detected. Sequences from chimpanzee, orangutan and human were also amplified, but they were shorter than predicted. We were unable to amplify sequences from spider monkey, salmon, several rodents, bandicoot, sheep and pig . Analysis of the restriction map revealed several conserved RE sites in the amplified sequences of the primates. The results support the view that monkey has more close relationship with human than any other species at molecular level.

WDB—300型微电脑电动机综合保护器

焦作矿务局电子设备厂研制的WDB-300型微电脑电动机综合保护器主要用于厂矿中小型交流电动机的综合保护。该保护器以8748单片机为主要元件,除具有采集数据准确、时限精密的过载反时限保护、短路保护、断相不平衡保护、漏电闭锁保护外,还具有如下几个特点:1.保护器的电源取自隔离变压器,并采用特殊的抗干扰手段;2.过载、短路、断相检测信号取自电流电压变换器;3.过载保护分档采用7个开关组合方式,可达到127档整定值;4.增设声光显示装置。