散线同心式绕组制造工艺

低压大功率电机散嵌绕组由于并绕根数多、线圈截面较大、绕组端部较厚,整型成为绕组制造过程的难点.同心式绕组嵌线方便,端部整型容易,解决了散嵌绕组嵌线过程整型难的问题.并从同心式绕组制造工艺进行分析,从中归纳总结了同心式散嵌绕组的制造经验,为制造类似电机提供了一定的参考.     

双层叠绕组发电机单元件横差保护特性分析

通过1号机横差保护动作的现象,对故障进行分析,得出测量双星形中性点电流作为双层叠绕组发电机单元件横差保护的,横差动作的原因可能是定子绕组匝间发生短路,也可能是转子匝间短路或者转子偏心引起磁场不均匀也会引起的结论,该结论对现场维护人员有一定得指导意义。     

Carbon nanotube composites fabricated through filament winding process for battery preheating application

Carbon nanotube (CNT) polymer composites have broad application prospects in thermal management as electrothermal heaters. Nevertheless, challenge remains in achieving high electrical conductivity for the composites due to the contradiction between CNTs and insulated polymers. To address this issue, herein, innovative use of interface strategy approach by constructing synergistic nanomaterial networks on carboxyl CNTs yarn winding composites for improving the interfacial adhesion and electrical performance. In the work, carboxyl CNTs yarn/CNTs-graphene oxide (GO) polyvinyl alcohol (PVA) composites (C-CY-HP-C) were proposed and manufactured via filament winding process. The as-constructed C-CY-HP-C demonstrated a remarkable interfacial shear strength of 2057.16 N mm⁻¹, which was 53.59% higher than that of control CNTs yarn/PVA winding composites. In addition, the C-CY-HP-C achieved an attractive electrical conductivity of 346.39 S cm⁻¹ owing to the electronic transmission channels were formed. Notably, the superior electrical conductivity facilitated a rapid-response of electrothermal performance for the C-CY-HP-C. It reached a steady-state temperature of 229.9°C within 10 s when the voltage was 1.2 V. Concurrently, it exhibited an impressive heating rate of 10.8°C min⁻¹ at an ambient temperature of −20°C as the battery surface heater. These findings shed light on the development of technique for battery preheating system based on CNTs yarn/polymer composites.     

偏心及返回导体对特高压用计量CT误差影响分析

为明确电能计量装置自身误差受电磁场影响程度,对特高压用计量电流互感器(CT)开展一次绕组偏心及返回导体对误差影响的定量分析。首先根据磁路平衡原理建立在圆柱坐标内CT误差数学模型,推导出不同位置的外加磁场点对CT误差影响计算公式,并结合实例得到有限元与解析解结果一致,证明推导公式的正确性;然后在二维电场中对1 000 k V工程中典型CT尺寸及一次电流进行磁场分布仿真,定量的得到对于特高压用计量CT,一次绕组偏心大于1/8的CT半径后会铁心内部会产生局部饱和,导致误差产生突变进而导致超差可能;此外,仿真结果指出外部返回导体距离CT中心应大于3倍CT半径后,返回导体引起的磁场对CT误差的干扰才能被忽略;最后搭建实际特高压误差测试平台对一次绕组偏心开展试验,测试数据与仿真结果趋势一致。     

一种变压器绕组变形综合检测仪器的设计

绕组变形是电力变压器正常运行过程中常见的一种故障隐患。准确诊断电力变压器绕组的变形情况,有助于保障电力系统的安全可靠运行。设计开发了一种兼具频率响应法和低压电抗法两种测量原理的变压器绕组变形综合检测仪器,其不仅可以满足频率响应法和低压电抗法的所有技术要求,而且结构轻便、操作简单,可方便地用于现场电力变压器绕组运行状况的有效检测和综合诊断。     

网络生丝网络速比的研究

本文研究了网络生丝在形成过程中的卷绕成网规律及网络速比对缫制网络生丝的影响，提出了缫制网络生丝的网络速比     

用Calahan法求解MOV保护绕组的波过程

用ＭＯＶ限制绕组过电压是一种非常有效的方法。本文在建立含ＭＯＶ保护绕组波过程的状态方程基础上，采用半隐格式Ｃａｌａｈａｎ法计及Ｍｏｖ的ｕ－Ｉ特性两种处理方法以及分块求递技术得到波过程的特性，数值分析分别与解析解和实验值作了比较，表明本文方法是可靠的。     

攀钢1450mm热轧带钢卷取塔形的控制

简述卷取塔形产生的原因及采取的措施，从而控制钢卷的质量，提高板厂的成材率和经济效益．     

Development and characteristics of superconductor for 70-MW class high-response excitation superconducting generator

The superconducting field winding of the 70-MW classhigh-response excitation superconducting generator requires a maximum operation current of 4.5 kA at the field of 6 T and needs to allow the field change of 10 T/s. In addition, superconductors have to meet the requirements of saddle-shape winding in the rotor slot and require the mechanical strength withstanding the centrifugal force as well as electromagnetic force. The developed conductor has the configuration of double stranded cable, consisting of NbTi, Cu and CuNi. An optimization was made, taking into account the requirement of low ac loss and high current density. The critical current of 13.6 kA was achieved at the field of 6 T and the ac loss was 6.9 kW/m³. The developed low-loss high-current density superconductor will be able to be applied to the field winding of the 70-MW class high-response excitation superconducting generator.     

A brushless three-phase synchronous motor using the armature winding as both load and DC excitation winding

This paper presents a new brushless three-phase synchronous motor which has no exciter. The technique applied to the motor provides an effective way for conventional brushless synchronous motors to simplify the system configuration. The stator of the motor is equipped with a double-star connected armature winding which has two neutral points. The rotor is a cylindrical one, which is equipped with a two-phase field winding. The field winding is connected with shaft-mounted rectifiers. A dc voltage is applied to the two neutral points of the armature winding to obtain the rotor excitation when the motor is operated at synchronous speed. At that time. the armature winding acts as a stator dc exciting winding while also acting as a load winding. In this paper the principle and characteristics of the motor are described. and the experimental results are shown. It is confirmed that with a 2-kW experimental machine, the proposed motor has good performance. For example, by adjusting the stator dc current, this motor power factor can easily be controlled within a wide range.