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Study on separation algorithm of convolutive mixing model and separation of mixing signals of multiple partial discharges 下载免费PDF全文
To identify individual partial discharges(PD)signals produced by multiple insulation defects in gas insolated switchgear (GIS),this paper analyses the mechanism of propagation and mixing of multiple PD electromagnetic wave signals in GIS cylinder and proposes the convolutive mixing model to describe it for a separation algorithm to acquire individual PD signals. With the non-stationary property,mixing PD signals are changed at time domain into a set consisting of short-time stationary PD signals and then the Molgedey-Schuster decorrelation approach is employed to separate these stationary PD signals at frequency domain. The correlation of the envelope of separated PD signals in this set is used to reconstruct PD signals to realize the separation of non-stationary UHF PD mixtures. The effective separation of actual UHF PD mixing signals validates the assumption of convolutive mixing process in GIS and also offers a new approach to the identification of mixing PD signals by external ultra-high frequency detection scheme from multiple insulation defects in GIS. 相似文献
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In order to classify the ultra high frequency (UHF) partial discharge (PD) signals resulting from four types of insulation defects in gas insulated switchgear (GIS), the complex wavelet transform is applied to extract features of UHF PD signals. Five statistical parameters including mean, variance, kurtosis, skewness and energy are used to quantize the scaling coefficients of the complex wavelet transform and describe the feature subsets of UHF PD signals.A critical index J is defined to select features according to their classification performance. Using the J criterion, five optimal features are selected from sixty UHF PD features and taken as the input of radial basis function neural network. The classification results show that the information of real part and image part of complex wavelet coefficients indicates the characteristics of UHF PD singles and the recognition effect is pretty good. To use db4 complex wavelet can get the best classification performance. 相似文献
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随着智能化GIS设备的发展,GIS设备上集成了大量电子设备。GIS设备开关操作产生的特快速瞬态电磁过程主要经由“传感器—二次电缆—智能组件”这段电路对电子设备产生电磁影响。笔者首先基于传输线网络理论建立了开关操作产生的地电位升对“传感器—二次电缆—智能组件”回路的耦合计算模型,然后通过验证实验证明了计算模型的有效性和准确性,最后对不同屏蔽层接地方式下的各传感器端口和智能组件各端口及端口间的骚扰电压进行了仿真研究。计算结果显示,各骚扰电压受接地方式的影响较大;通过选择合适的接地方式,可以有效地抑制开关操作电磁骚扰。 相似文献
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《保鲜与加工》2003,(10):84
Based on existing research, this paper analyzes and compares the phase information characters between partial discharge signal (PD) and its disturbance, and also extracts the feature of Partial Discharge with complex wavelets in noise environment. The research demonstrates that complex wavelets are more superior to original real wavelets in identifying Partial Discharge signal, and those simulated applications and the datum from laboratory can guarantee the effectiveness of the extraction of the feature of Partial Discharge and the restraint of the strong electromagnetic disturbance. 相似文献
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The propagation characteristics of the partial discharge’s ultrasonic signal in the stator of generator and the difference between the ultrasonic signal and the running background noise are analyzed with experiments. Ultrasonic online location for partial discharge is proven to be feasible. For non blind area monitoring, the stator is divided into several equal parts. Locating equations are established with electroacoustic detection method and optimized with genetic algorithm. The simulation results indicate that the proposed method of ultrasonic online location for the partial discharge in the stator of generator is correct. 相似文献
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In this paper according to the relationships between indoor-outdoor climate parameters, indoor thermal environment parameter and heat insulation parameters of enclosure, the control condition of indoor thermal environment and the control parameters of heat insulation-energy saving are advanced. Prescribing a quality limit for the parameters, the control indexes for the heat insulation energy saving of the enclosure are given. 相似文献
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为了研究小麦不同器官全磷含量的遗传模型随机选用8个亲本,组配成28个双列杂交组合,在正常和肥水亏缺胁迫两种环境下,进行随机区组试验,采用Hayman 双列杂交分析方法,研究了不同器官磷含量的遗传模型。结果表明,在正常和肥水亏缺两种环境下子粒、叶片和茎秆全磷含量的遗传均为加性—显性—上位性;正常环境下子粒和叶片全磷含量的显性遗传表现为增效,正常环境下茎秆和肥水亏缺胁迫环境下子粒、叶片和茎秆的全磷含量的先行遗传表现为减效。最后,根据各性状的遗传模型和基因在亲本中的分布,讨论了杂交后代的选择和亲本选配。 相似文献
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山区高油玉米高产优质栽培模式研究 总被引:1,自引:1,他引:1
为探索在黔西北山区种植高油玉米高产优质的栽培模式,促进山区种植业结构调整,采用多元二次正交回归旋转组合设计,研究了高油玉米产量、产油量与四个主要栽培因子——种植密度及N、P、K肥施用量之间的关系,建立了数学模型,解析了各因素对产量、产油量的效应,通过计算机模拟寻优,筛选出了黔西北山区高油玉米高产优质的农艺综合方案:密度62463~63710株/ hm2;N肥(纯N)321.79~359.04kg/hm2;P肥(P2O5)319.94~345.32 kg/hm2;K肥(K2O)293.64~333.30 kg/hm2。 相似文献
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苎麻种植密度对重金属Pb、As富集能力影响研究 总被引:2,自引:0,他引:2
本研究以两个苎麻主栽品种为研究对象,设计了2种种植密度,研究苎麻在Pb、As污染农田中的生长情况及植物体内不同部位的Pb、As含量,期望从中发现不同的种植密度对苎麻产量以及对重金属Pb、As富集能力的影响。试验结果表明:不同的种植密度对苎麻的产量影响较大,“湘3”和“中1”正常密度产量分别为10.49kg/亩和8.80kg/亩,而高密度依次分别达到22.82 kg/亩和20.86 kg/亩;正常密度2个品种苎麻地上部Pb、As含量均高于高密度,Pb、As的小区迁移量都是湘3高密度最高,分别达到4.97mg/m2和0.194mg/m2,高密度会减少苎麻单株地上部重金属的含量,但是总迁移量有所提高。 相似文献
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为了探索包衣尿素养分释放规律和对育苗生长的影响,以普通尿素为对照,分别按等氮量设置了L30、L60和S60三种释放类型树脂包衣尿素处理并进行黄瓜穴盘基质育苗试验。在第15、21、29、36天测定了基质、肥料及幼苗中氮素含量变化情况,并在最后一天还测定了壮苗指数。结果表明:不同处理间基质中无机氮含量、幼苗吸氮量以及壮苗指数差异显著,其中L30处理氮素的释放与黄瓜幼苗吸氮趋势相吻合。幼苗株高、茎粗、单株干物重均优于CK处理,壮苗指数提高20.2%。因此,采用L30型控释氮肥,可以实现一次底肥投入,达到育苗期间免追氮肥的目标。 相似文献
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内蒙古河套灌区春小麦高产栽培优化农艺措施及数学模型的研究 总被引:6,自引:2,他引:6
本文通过三因素二次通用旋转设计试验,对内蒙古河套灌区春小麦高产栽培的主要农艺措施进行优化分析与数学模拟,确定了春小麦高产栽培优化农艺措施为亩播量18~23kg,施N20~23kg,施P_2O_510~13kg。同时还明确了河套灌区春小麦高产栽培的亩产量与氮磷和播量之间的相关关系,即随着目标产量的提高,在增施氮肥和磷肥的基础上,密度呈下降的趋势。 相似文献