基于罗氏线圈和微分环的雷电流在线监测综述

雷电流在线监测对于电力系统的稳定运行具有重要意义。罗氏线圈和微分环是目前获得雷电流全波波形的重要传感器。文中详细介绍了罗氏线圈及微分环的测量原理、国内外发展现状以及优劣势,并探讨了今后可能的研究方向。最后提出了雷电流在线监测系统存在的供电问题,并提出了可行的解决方案。     

交直流复合电压下油纸绝缘气隙局部放电与产气特性分析(英文)

Oil-paper insulation is used within most of high voltage direct current(HVDC) converter transformers.Partial discharge(PD) in oil-paper insulation is a major reason for the development of internal faults in HVDC converter transformer,while PDs in oil-paper insulation mainly occur in terms of gas cavity discharges.There are few study results on the development characteristics of partial discharges in oil-paper insulation and dissolved gases in oils of HVDC converter transformers.Based on a gas cavity discharge model of oil-paper insulation,the present study investigates the development characteristics of partial discharges under AC-DC combined voltages and emphatically examines the variation characteristics of dissolved gases in the discharge development process.Experiment and analysis results show that the characteristics of partial discharges and dissolved gases in oils under AC-DC combined voltages are appreciably different with those under AC voltage.These results provide theoretical support for further research on partial discharges and on dissolved gases of other internal insulating defects and are helpful for the fault diagnosis of HVDC converter transformers.     

添加剂对变压器油腐蚀性和油色谱测定结果的影响

为研究变压器油中添加抗氧化剂二苄基二硫醚（DBDS）后的腐蚀特性,以及金属减活剂抑制腐蚀的特性,在实验室以2种油（简称油A和油B）为主要研究对象,进行了相关加速热老化试验。首先根据ASTM D1275B法进行相关加速热老化试验,检测腐蚀性硫化物;然后对添加一定量金属减活剂（Irgament 39）的油B进行90 ℃下的加速热老化试验,分析油中溶解气体含量变化。研究发现：DBDS为腐蚀性硫化物,而金属减活剂不是;金属减活剂能有效防止硫腐蚀的发生,但其本身随热老化快速消耗;添加金属减活剂之后,油中溶解气体H₂、CO、CO₂等含量明显增加,需关注这些溶解气体的分析结果及其对油色谱测定结果的影响,特别是对变压器故障进行判断时,需考虑这一因素,以防误判。     

交直流复合电压下的油纸绝缘局部放电统计图谱研究(英文)

The converter transformer is one of the most critical equipments in high-voltage direct current transmission systems.Valve-side windings have to withstand complex stresses combined of AC,DC,and pulsed voltages.Partial discharges(PDs) can thus easily occur in oil-impregnated paper insulation.The current paper presents the statistical phase-resolved distributions of partial discharges in oil-paper insulation under combined AC and DC voltage stress.First,the voltages in the converter transformer were analyzed.In the experiments,four artificial insulation defect models were designed to generate PD signals under AC-DC combined voltage stress detected by a Rogowski coil sensor.Histograms including the φ-q-n data of these PD signals were created.The variations of φ-q-n data generated by PDs in different insulation defect models were analyzed while increasing the test voltage.Experimental results showed that the PD phase-resolved distributions of different insulation defect models were different from one another.The findings of the current study are useful in further research on the mechanism and pattern recognition of PDs in converter transformers.     

变压器油中Cu2 S生成规律及影响

变压器油中的腐蚀性硫可对变压器绝缘性能造成不良影响。为研究变压器油中腐蚀性硫对铜导线及油纸绝缘的影响特性,在实验室以某油品（油样1）为主要研究对象（以另一油品（油样2）作为对比）,在130 ℃和150 ℃下进行加速热老化试验。通过分析老化过后的裸铜片、纸包铜片、绝缘纸和油样相关特性的变化,发现油样1具有明显的硫腐蚀性,而油样2没有这一特性;铜片表面及绝缘纸内表面的腐蚀程度随着老化时间的增加而加剧;Cu2S在绝缘纸表面的沉积不仅与腐蚀程度有关,还与老化时间有关;Cu2S的沉积会改变铜片的表面结构、绝缘纸的纤维分布以及油-纸复合绝缘介质的介电特性,沉积了Cu2S的复合介质,其击穿场强大大降低。关于变压器油腐蚀性硫防治措施的研究结果将另行详述。     

电力变压器油纸绝缘可靠性与老化特征参量间的相关性

在长期连续运行中,油浸式电力变压器的整体寿命主要取决于油纸绝缘的寿命,为此,研究变压器油纸绝缘可靠性与特征参量之间的关联特性,有助于准确判断变压器的可靠性水平,保证其安全稳定运行.首先进行油纸绝缘试品的可靠性试验;然后利用极大似然参数估计法求取其寿命的Weibull分布模型参数;最后结合油纸绝缘各老化特征参量的测量结果...     

基于遗传算法优化神经网络的智能配电网线损计算研究

为实现结构复杂、低压台区智能配电网的线损计算,首先构建误差反向传播(BP)神经网络模型以计算配电网理论线损,然后利用遗传算法(GA)深度优化神经网络并建立GA-BP模型。基于上述模型计算配电网的理论线损率并对模型计算性能进行比对分析。结果表明,使用GA-BP模型进行线损计算比单一BP模型计算的平均绝对误差减少约0.273%。应用遗传算法优化后的神经网络线损率计算模型较单一BP神经网络模型具有更好的非线性拟合能力和更高的计算精度。     

用于雷电流在线监测的多层PCB微分环理论分析

PCB(Printed Circuit Board)微分环作为一种新的测量雷电流的非接触式传感器,可实现数字化布线及全自动生产,克服了传统微分环的诸多不利因素。由于单层PCB微分环测量雷电流的灵敏度不高,本文从微分环的测量原理出发,由对单层PCB微分环测量原理分析扩展到多层微分环,得到了多层PCB微分环的相关计算公式。并给出了多层PCB微分环的等效电路,以及等效电路中电容和电感的计算公式与推导过程。最后,本文通过Matlab软件仿真分析了多层PCB微分环的结构参数对其测量性能的影响。仿真结果表明多层PCB微分环的测量灵敏度与微分环的层数存在着简单的线性关系,层数越多,灵敏度越高;并且多层PCB微分环的层数越多、层间距越小、与屏蔽壳之间的距离越小,其测量带宽就越小。本文的研究成果为后续多层PCB微分环和雷电流监测系统的实物研制奠定了理论基础。