High-voltage line ice covering is not only related to the stable operation of the power grid, but also affects people's normal life and the operation of industrial and mining enterprises. At present, some exploration and research on the anti-ice melting technology of transmission lines have been carried out in foreign countries, and some research results have been applied to the process of transmission line melting, and the effect is also ideal after practice. However, due to the incomplete insulation of the overhead ground wire, when the ice is serious, the measures cannot be taken, resulting in the damage of the tower and the shutdown of the line. For this reason, the common ice melting methods are compared according to the ice melting mechanism. Three kinds of ground wire ice melting schemes are proposed, namely, ground wire series loop mode, ground wire parallel mode and long line section mode, to improve the overall ice melting capacity and range of high voltage transmission lines, and further improve the reliability of transmission lines.
MOSFET-based power electronics systems have high-reliability requirements, and a high-accuracy fault diagnosis method is necessary. However, imperfect conditions such as severe signal noise and poor consistency exist in actual products. Conventional fault diagnosis methods are difficult to identify faults accurately. This paper describes a simulation-based testability design method for batch products considering noise immunity. First, the components' soft and hard fault models are determined with failure mode and effect analysis (FMEA), and the circuit simulation model is constructed. Then, the fault injection simulation is performed to structure the dependency matrix. The test points scheme is selected and optimized by extracting noise immunity characteristics of different types of signals. Finally, a power distribution system is taken as a case study for the testability design method, and the effectiveness of the test points is evaluated through simulation and experiment verification.
现有的估测方法与实际值存在出入,为此,本文提出了一种配电网负荷供应能力模糊估测方法.首先,对采集的电网数据赋予权重,形成数据序列,并剔除和填补异常数据.其次,使用试探法建立精度较高的LSC模型,以满足设备不过载和节点电压在阈值范围内的条件.再次,计算目标函数,添加节点负荷约束,并使用直流潮流计算方法消除母线电压变化,得到配电网中负荷供应的最大有功出力.最后,建立灰色估测模型估计数据组合,利用隶属度函数进行模糊综合评判.实验结果表明,该方法的估测值与实际值曲线保持一致,能提升估测模型的准确程度.
本研究以河南省焦作市出产的铝矾土尾矿为主要原料,以高岭石为物相调控剂,通过高温煅烧制备刚玉-莫来石复相材料,采用XRD和SEM研究煅烧温度和高岭石添加量对其物相组成和显微形貌的影响规律,采用热力学计算进一步探讨了铝矾土尾矿在高温下物相转变的机制.结果表明,铝矾土尾矿在1000℃以上的温度热处理后,物相转变产物为莫来石、刚玉和石英;添加高岭石可促进铝矾土尾矿向莫来石转变,在1 100℃以上的温度热处理后的产物物相以莫来石和刚玉为主,可望作为刚玉-莫来石复相原料被应用于耐高温材料领域.
自动化综合实践课程以柔性产线为载体,结合了 PLC技术、传感器技术、运动控制技术和通信技术等多种技术,是电气工程及其自动化专业的必修课程之一.在传统的自动化综合实践课程学习中,通常采用西门子S7协议,三菱CC-LINK协议或Modbus TCP通信协议等用于工业设备间的通信.Profinet IO通信是基于工业以太网的开放现场总线,可以实时快速地将IO设备直接连接工业以太网,实现设备间的高速通信功能,从而提高自动化综合实践课程的学习效率.
