高压电能计量装置设计选型和接线方式问题探讨

指出了当前高压电能计量装置在设计选型和接线方式方面存在的问题,针对在线运行高压电能计量装置设计选型和接线方式对其计量结果准确性和可靠性的影响进行了分析探讨,提出了改进建议,并对改进前后2种不同的高压电能计量装置设计选型和接线方式的实际电量进行了比对考核。     

三水地区配电网中性点接地方式及其消弧系统的运行分析

介绍了三水地区的10kV配电网中性点接地方式以及对消弧线圈的选择。根据三水高丰变电站的运行记录,分析了KDXH型智能化快速消弧系统应用效果,阐述了其在高阻接地或弧光接地情况下具有提供正确补偿及响应速度快的性能。     

小电流接地系统单相接地故障分析与处理

以介休电网为例,综述了小电流接地系统发生单相接地短路故障的原因、影响,总结了预防、处理小电流接地系统发生单相接地短路故障的措施、步骤和办法。     

电镦机中加热电流的BP神经网络预测

以电镦工艺参数作为学习样本,选取了镦粗速度、砧子速度、镦粗压力作为输入参数,加热电流作为输出参数,运 用神经网络BP模型中的Levenberg-Marguardt优化算法对学习样本优化建模,将优化网络的预测结果与实测结果进行 比较,结果表明,BP网络可以很好实现电镦机中加热电流的预测。     

Thermal analysis of EAST neutral beam injectors for long-pulse beam operation

Two sets of neutral beam injectors(NBI-1 and NBI-2) have been mounted on the EAST tokamak since 2014. NBI-1 and NBI-2 are co-direction and counter-direction, respectively. As with indepth physics and engineering study of EAST, the ability of long pulse beam injection should be required in the NBI system. For NBIs, the most important and difficult thing that should be overcome is heat removal capacity of heat loaded components for long-pulse beam extraction. In this article, the thermal state of the components of EAST NBI is investigated using water flow calorimetry and thermocouple temperatures. Results show that(1) operation parameters have an obvious influence on the heat deposited on the inner components of the beamline,(2) a suitable operation parameter can decrease the heat loading effectively and obtain longer beam pulse length, and(3) under the cooling water pressure of 0.25 MPa, the predicted maximum beam pulse length will be up to 260 s with 50 keV beam energy by a duty factor of 0.5. The results present that, in this regard, the EAST NBI-1 system has the ability of long-pulse beam injection.     

城市配网中性点接地方式的选择

文中比较了城区配电网中性点不同接地方式的优缺点,指出对电缆为主的城区配网,中性点应优先采用经电阻接地的方式。同时提出了中性点接地电阻选择时应注意的若干事项。     

Using Adaptive Discrete-Time Gas Supply Control for Long Pulse Arc Discharge of Ion Source on NBI

A control model of gas supply system is introduced for ion source and an adaptive discrete-time control algorithm to regulate the hydrogen injection. A real-time feedback control system （RFCS） is designed to control the gas supply for ion source based on the control model and the discrete-time control algorithm. The experimental results have proved that RFCS could regulate the gas supply smoothly, suppress the arc＇s abrupt over-current at the end of the ion source discharging, prolong the discharge pulse and stabilize the ion concentration. With RFCS, the ion source for neutral beam injection has reached its longest pulse with a length of 4.5 seconds in a stable status.     

Temperature Dependence of Cobalt Release Rate from Stainless Steel in Neutral Water

In order to evaluate the release source of Co from heated tubes of the feedwater line of BWR, Co release rate measurements were carried out by measuring ⁶⁰Co released from irradiated stainless steel in contact with neutral water at an oxygen concentration of 20 ppb. The temperature- and time-dependences on Co release rate were studied for 670 h release experiments; the rate was found to decrease in proportion to t ^?frac12 (t ^?frac12 (t: exposure time) and to have its maximum value around 240°C. An empirical equation was obtained for the Co release rates in the temperature range of 150~240°C.

R_Co = 1.9 × 10⁶ exp (-14,300/(RT)) t ^?frac12

where R _co Co release rate (mg/(dm²·month)), R: Gas constant (cal/(mol·deg.)), T: Exposure temperature (K) and t: Exposure time (h). Decrease in the Co release rate with temperatures over 250°C, seemed to be ascribed to the formation of a protective oxide layer on the surface of stainless steel.     

欧盟碳关税落地对中欧贸易的影响及应对策略

2023 年 5 月 16 日,欧盟宣布将碳边境调节机制(Carbon Border Adjustment Mechanism,CBAM)法案文本在《欧盟官方公报》上正式发布,并于次日(2023 年 5 月 17 日)正式生效,这是全球首个碳关税机制。欧盟是中国第二大贸易伙伴和第二大出口市场,欧盟开征碳关税必将对中国的对欧出口贸易和经济发展造成较大影响。该文对欧盟 CBAM 的发展历程、最新动态、具体内容和征收方法做了详细介绍,并在此基础上,依据中国海关进出口统计数据,分析了 CBAM 对中欧贸易的影响。目前,受影响较大的行业主要是钢铁和铝,但是未来,欧盟还将对 CBAM 进行重新评估,以确定是否扩大征收范围。中国应积极采取各种应对策略,以维护外贸企业的合法权益。     

中性点不接地系统中单相接地保护的新原理探讨

提出了一种反映中性点不接地电网中单相接地故障的新保护原理，理论分析和MATLAB仿真结果表明。对于非故障线路，故障相与非故障相之间工频电流变化量相近且很小；而对于故障线路，故障相工频电流变化量远远大于非故障相工频电流变化量．该保护原理就是利用比较线路各相之间工频电流的变化量而构成，使保护具有较好的灵敏性和可靠性．