A monitoring system is an important guarantee of safety in a production mine. However, not all monitoring substations pass the electrical fast transient/burst （EFT/B） immunity test and the explosion-proof test simul...A monitoring system is an important guarantee of safety in a production mine. However, not all monitoring substations pass the electrical fast transient/burst （EFT/B） immunity test and the explosion-proof test simultaneously. To enhance the immunity, the values of capacitance and inductance should be increased, which are actually limited by coal mine explosion-proof standards. Hence, for the first time, an active filter was applied in an electromagnetic interference （EMI） output filter. As a result, the interference within 30 MHz clearly weakened, but the frequency spectrum had a wide range. An EMI input filter and ferrite beads were adopted to restrain higher frequency interference. An output interference spectrogram of the substation was obtained with an analyzer. The results indicate that the improved complex filtering markedly help to control interference. With the support of improved complex filtering and other enhancing immunity means about I/O ports, the substation managed to pass both the EFT/B immunity test and the explosion-proof test synchronously. We conclude that improved complex filtering is of vital importance in enhancing the electromagnetic compatibilitv （EMC） of the coal mine monitoring system.展开更多
Underground Electro Magnetic Interference (EMI) has become so serious that there were false alarms in monitoring system,which induced troubles of coal mine safety in production.In order to overcome difficulties caused...Underground Electro Magnetic Interference (EMI) has become so serious that there were false alarms in monitoring system,which induced troubles of coal mine safety in production.In order to overcome difficulties caused by the explosion-proof enclosure of the equipments and the limitation of multiple startup and stop in transient process during EMI measurement,a novel technique was proposed to measure underground EMI distri- bution indirectly and enhance Electromagnetic Campatibility(EMC) of the monitoring sys- tem.The wavelet time-frequency analysis was introduced to underground monitoring sys- tem.Therefore,the sources,the startup time,duration and waveform of EMI could be as- certained correctly based on running records of underground electric equipments.The electrical fast transient/burst (EFT/B) was studied to verify the validity of wavelet analysis. EMI filter was improved in accordance of the EMI distribution gotten from wavelet analysis. Power port immunity was developed obviously.In addition,the method of setting wavelet thresholds was amended based upon conventional thresholds in the wavelet filter design. Therefore the EFT/B of data port was restrained markedly with the wavelet filtering.Coor- dinative effect of EMI power and wavelet filter makes false alarms of monitoring system reduce evidently.It is concluded that wavelet analysis and the improved EMI filter have enhanced the EMC of monitoring system obviously.展开更多
为了在设计的早期阶段,以仿真的方式预测电子产品在电快速瞬变脉冲群(electrical fast transient/burst,EFT/B)抗扰度试验中的性能,需要建立干扰源发生器及标准耦合装置的仿真模型。为适应EFT/B抗扰度试验标准的修订和补充,提出一种系...为了在设计的早期阶段,以仿真的方式预测电子产品在电快速瞬变脉冲群(electrical fast transient/burst,EFT/B)抗扰度试验中的性能,需要建立干扰源发生器及标准耦合装置的仿真模型。为适应EFT/B抗扰度试验标准的修订和补充,提出一种系统化的EFT/B发生器等效电路的建模方法。首先,基于对发生器充放电物理过程的分析,提出开路条件(1kΩ)下发生器输出波形的解析表达式,且表达式系数可根据仪器厂商的校准波形加以确定;其次,基于该解析式并采用阶跃函数激励,得到脉冲形成网络的传递函数,并分别采用恒电阻法及参数化电网络综合法得到脉冲形成网络的等效电路;最后,对等效电路各元件参数进行归一化处理,并根据发生器在匹配条件下(50Ω)的校准波形确定归一化系数。将EFT/B发生器的等效电路模型与标准容性耦合夹电路模型进行连接仿真,通过仿真与测量结果的对照验证了所提方法的合理性。展开更多
基金Project 50674093 supported by the National Natural Science Foundation of China
文摘A monitoring system is an important guarantee of safety in a production mine. However, not all monitoring substations pass the electrical fast transient/burst （EFT/B） immunity test and the explosion-proof test simultaneously. To enhance the immunity, the values of capacitance and inductance should be increased, which are actually limited by coal mine explosion-proof standards. Hence, for the first time, an active filter was applied in an electromagnetic interference （EMI） output filter. As a result, the interference within 30 MHz clearly weakened, but the frequency spectrum had a wide range. An EMI input filter and ferrite beads were adopted to restrain higher frequency interference. An output interference spectrogram of the substation was obtained with an analyzer. The results indicate that the improved complex filtering markedly help to control interference. With the support of improved complex filtering and other enhancing immunity means about I/O ports, the substation managed to pass both the EFT/B immunity test and the explosion-proof test synchronously. We conclude that improved complex filtering is of vital importance in enhancing the electromagnetic compatibilitv （EMC） of the coal mine monitoring system.
基金the National Natural Science Foundation of China(50674093)
文摘Underground Electro Magnetic Interference (EMI) has become so serious that there were false alarms in monitoring system,which induced troubles of coal mine safety in production.In order to overcome difficulties caused by the explosion-proof enclosure of the equipments and the limitation of multiple startup and stop in transient process during EMI measurement,a novel technique was proposed to measure underground EMI distri- bution indirectly and enhance Electromagnetic Campatibility(EMC) of the monitoring sys- tem.The wavelet time-frequency analysis was introduced to underground monitoring sys- tem.Therefore,the sources,the startup time,duration and waveform of EMI could be as- certained correctly based on running records of underground electric equipments.The electrical fast transient/burst (EFT/B) was studied to verify the validity of wavelet analysis. EMI filter was improved in accordance of the EMI distribution gotten from wavelet analysis. Power port immunity was developed obviously.In addition,the method of setting wavelet thresholds was amended based upon conventional thresholds in the wavelet filter design. Therefore the EFT/B of data port was restrained markedly with the wavelet filtering.Coor- dinative effect of EMI power and wavelet filter makes false alarms of monitoring system reduce evidently.It is concluded that wavelet analysis and the improved EMI filter have enhanced the EMC of monitoring system obviously.
文摘为了在设计的早期阶段,以仿真的方式预测电子产品在电快速瞬变脉冲群(electrical fast transient/burst,EFT/B)抗扰度试验中的性能,需要建立干扰源发生器及标准耦合装置的仿真模型。为适应EFT/B抗扰度试验标准的修订和补充,提出一种系统化的EFT/B发生器等效电路的建模方法。首先,基于对发生器充放电物理过程的分析,提出开路条件(1kΩ)下发生器输出波形的解析表达式,且表达式系数可根据仪器厂商的校准波形加以确定;其次,基于该解析式并采用阶跃函数激励,得到脉冲形成网络的传递函数,并分别采用恒电阻法及参数化电网络综合法得到脉冲形成网络的等效电路;最后,对等效电路各元件参数进行归一化处理,并根据发生器在匹配条件下(50Ω)的校准波形确定归一化系数。将EFT/B发生器的等效电路模型与标准容性耦合夹电路模型进行连接仿真,通过仿真与测量结果的对照验证了所提方法的合理性。
