>Transformer faults are quite complicated phenomena and can occur due to a variety of reasons.There have been several methods for transformer fault synthetic diagnosis,but each of them has its own limitations in re...>Transformer faults are quite complicated phenomena and can occur due to a variety of reasons.There have been several methods for transformer fault synthetic diagnosis,but each of them has its own limitations in real fault diagnosis applications.In order to overcome those shortcomings in the existing methods,a new transformer fault diagnosis method based on a wavelet neural network optimized by adaptive genetic algorithm(AGA)and an improved D-S evidence theory fusion technique is proposed in this paper.The proposed method combines the oil chromatogram data and the off-line electrical test data of transformers to carry out fault diagnosis.Based on the fusion mechanism of D-S evidence theory,the comprehensive reliability of evidence is constructed by considering the evidence importance,the outputs of the neural network and the expert experience.The new method increases the objectivity of the basic probability assignment(BPA)and reduces the basic probability assigned for uncertain and unimportant information.The case study results of using the proposed method show that it has a good performance of fault diagnosis for transformers.展开更多
In this paper, a wavelet based fuzzy neural network for interval estimation of processed data with its interval learning algorithm is proposed. It is also proved to be an efficient approach to calculate the wavelet c...In this paper, a wavelet based fuzzy neural network for interval estimation of processed data with its interval learning algorithm is proposed. It is also proved to be an efficient approach to calculate the wavelet coefficient.展开更多
为了提高远距离无线电(Long Range Radio,LoRa)系统定位精度,提出利用接收信号强度指示(Received Signal Strength Indication,RSSI)测距和三边定位方法结合小波神经网络模型对LoRa节点进行定位。首先分析了RSSI测距、三边定位的原理和...为了提高远距离无线电(Long Range Radio,LoRa)系统定位精度,提出利用接收信号强度指示(Received Signal Strength Indication,RSSI)测距和三边定位方法结合小波神经网络模型对LoRa节点进行定位。首先分析了RSSI测距、三边定位的原理和实现方法,给出了基于RSSI测距方法求解LoRa网关与LoRa节点间距离的步骤。然后利用3层融合型小波神经网络搭建了LoRa节点定位模型,选取Morlet小波为隐含层神经元的激励函数,选取Sigmoid阈值函数为输出层函数,将LoRa节点到3个LoRa网关的距离作为输入层数据,节点定位模型转换并输出LoRa节点位置的归一化横坐标和纵坐标。最后利用LoRa网关模块和LoRa节点模块搭建了LoRa节点定位实验系统并进行了实验测试,通过实验数据分析得出了RSSI测距参数并利用三边定位算法和小波神经网络节点定位模型实现了待定位LoRa节点的精准定位。实验结果表明,所提算法的定位精度为1.033 m,优于四点质心定位算法和传统三边定位算法。展开更多
基金Project Supported by National Natural Science Foundation of China （ 50777069 ）.
文摘>Transformer faults are quite complicated phenomena and can occur due to a variety of reasons.There have been several methods for transformer fault synthetic diagnosis,but each of them has its own limitations in real fault diagnosis applications.In order to overcome those shortcomings in the existing methods,a new transformer fault diagnosis method based on a wavelet neural network optimized by adaptive genetic algorithm(AGA)and an improved D-S evidence theory fusion technique is proposed in this paper.The proposed method combines the oil chromatogram data and the off-line electrical test data of transformers to carry out fault diagnosis.Based on the fusion mechanism of D-S evidence theory,the comprehensive reliability of evidence is constructed by considering the evidence importance,the outputs of the neural network and the expert experience.The new method increases the objectivity of the basic probability assignment(BPA)and reduces the basic probability assigned for uncertain and unimportant information.The case study results of using the proposed method show that it has a good performance of fault diagnosis for transformers.
文摘In this paper, a wavelet based fuzzy neural network for interval estimation of processed data with its interval learning algorithm is proposed. It is also proved to be an efficient approach to calculate the wavelet coefficient.
文摘为了提高远距离无线电(Long Range Radio,LoRa)系统定位精度,提出利用接收信号强度指示(Received Signal Strength Indication,RSSI)测距和三边定位方法结合小波神经网络模型对LoRa节点进行定位。首先分析了RSSI测距、三边定位的原理和实现方法,给出了基于RSSI测距方法求解LoRa网关与LoRa节点间距离的步骤。然后利用3层融合型小波神经网络搭建了LoRa节点定位模型,选取Morlet小波为隐含层神经元的激励函数,选取Sigmoid阈值函数为输出层函数,将LoRa节点到3个LoRa网关的距离作为输入层数据,节点定位模型转换并输出LoRa节点位置的归一化横坐标和纵坐标。最后利用LoRa网关模块和LoRa节点模块搭建了LoRa节点定位实验系统并进行了实验测试,通过实验数据分析得出了RSSI测距参数并利用三边定位算法和小波神经网络节点定位模型实现了待定位LoRa节点的精准定位。实验结果表明,所提算法的定位精度为1.033 m,优于四点质心定位算法和传统三边定位算法。
