This article presents an extensive examination and modeling of Capacitor Coupled Substations (CCS), noting some of their inherent constraints. The underlying implementation of a CCS is to supply electricity directly f...This article presents an extensive examination and modeling of Capacitor Coupled Substations (CCS), noting some of their inherent constraints. The underlying implementation of a CCS is to supply electricity directly from high-voltage (HV) transmission lines to low-voltage (LV) consumers through coupling capacitors and is said to be cost-effective as compared to conventional distribution networks. However, the functionality of such substations is susceptible to various transient phenomena, including ferroresonance and overvoltage occurrences. To address these challenges, the study uses simulations to evaluate the effectiveness of conventional resistor-inductor-capacitor (RLC) filter in mitigating hazardous overvoltage resulting from transients. The proposed methodology entails using standard RLC filter to suppress transients and its associated overvoltage risks. Through a series of MATLAB/Simulink simulations, the research emphasizes the practical effectiveness of this technique. The study examines the impact of transients under varied operational scenarios, including no-load switching conditions, temporary short-circuits, and load on/off events. The primary aim of the article is to assess the viability of using an established technology to manage system instabilities upon the energization of a CCS under no-load circumstances or in case of a short-circuit fault occurring on the primary side of the CCS distribution transformer. The findings underscore the effectiveness of conventional RLC filters in suppressing transients induced by the CCS no-load switching.展开更多
Active power filter (APF) using novel virtual line-flux-linkage oriented control strategy can not only realizes no phase-locked-loop (PLL) control, but also achieves a good inhibitory effect to interfere. However, the...Active power filter (APF) using novel virtual line-flux-linkage oriented control strategy can not only realizes no phase-locked-loop (PLL) control, but also achieves a good inhibitory effect to interfere. However, there are some problems in the conventional method, such as the error of amplitude, the shift of phase angle and the non-determinacy of initial oriented angle. In this paper, two one-order low-pass filters are adopted instead of the pure integrator in the virtual line-flux-linkage observer, which can steady the phase and amplitude. Furthermore, an original scheme of harmonics detection under the rotating coordinate is advanced based on the simplified space vector pulse width modulation (SVPWM) strategy. Meanwhile, by using the new SVPWM algorithm, the voltage space vector diagram of the three-level inverter can be simplified and applied into that of two-level inverter, and this makes the control for Neutral Point potential easier.展开更多
Power line(PL)interference is one significant artifact in electrocardiography(ECG)that needs to be reduced to ensure accurate recording of cardiac signals.Because PL interference is non-stationary and has varying freq...Power line(PL)interference is one significant artifact in electrocardiography(ECG)that needs to be reduced to ensure accurate recording of cardiac signals.Because PL interference is non-stationary and has varying frequency,phase,and amplitude in ECG measurement,adaptive techniques are often necessary to track and cancel the interference.In this paper we present a phase-locked loop(PLL)-based adaptive filter to cancel PL interference.The PLL obtains the reference signal that is fed into the adaptive filter to remove the PL interference at the central frequency of 50 Hz.It is found that the technique can effectively cancel PL interference in real ECG signals and,when compared with some existing techniques such as least mean squares(LMS)adaptive filter,the new technique produces better results in terms of signal-to-interference ratio(SIR).展开更多
Two methods for improving the equidriving power-frequency characteristics of broad-band high power klystrons are presented. One is that a comb-line bandpass filter with someattenuation properties is inserted between t...Two methods for improving the equidriving power-frequency characteristics of broad-band high power klystrons are presented. One is that a comb-line bandpass filter with someattenuation properties is inserted between the TWT driver and the klystron for compensatingthe gain-frequency characteristics of the klystron to get the required equidriving power-frequencycharacteristics. The other is that a reactive element is connected with the input cavity to changeits resonance frequencies f<sub>0</sub> and Q<sub>L</sub>, and thus to improve the power-frequency characteristics ofthe klystron.展开更多
机载激光雷达(Light Detection and Ranging,LiDAR)技术作为一种能够在短时间内高效获取地面点云数据的新型测绘技术,目前已经在三维地表模型重建、电力巡检中发挥着重要的作用。为了更加有效地实现电力线测绘,本文设计并实现了基于机载...机载激光雷达(Light Detection and Ranging,LiDAR)技术作为一种能够在短时间内高效获取地面点云数据的新型测绘技术,目前已经在三维地表模型重建、电力巡检中发挥着重要的作用。为了更加有效地实现电力线测绘,本文设计并实现了基于机载LiDAR点云数据的电力线提取与重建方法。首先,通过改进形态学滤波法实现地面点与地物点分割,并通过高差阈值实现电力线点粗提取;其次,对粗提取电力线点进行栅格化处理与拟合残差计算,将计算结果与临界阈值对比实现电力线候选点集的提取;最后,通过双重K-means算法以及RANSAC算法实现单根电力线的提取与重建。使用福建北电南送特高压交流输变电工程中实测的部分机载LiDAR点云数据进行实验,结果表明:本文提出方法对电力线候选点集提取正确率在98%以上,较传统方法正确率更高,验证了本文电力线提取方法的有效性与优越性。展开更多
文摘This article presents an extensive examination and modeling of Capacitor Coupled Substations (CCS), noting some of their inherent constraints. The underlying implementation of a CCS is to supply electricity directly from high-voltage (HV) transmission lines to low-voltage (LV) consumers through coupling capacitors and is said to be cost-effective as compared to conventional distribution networks. However, the functionality of such substations is susceptible to various transient phenomena, including ferroresonance and overvoltage occurrences. To address these challenges, the study uses simulations to evaluate the effectiveness of conventional resistor-inductor-capacitor (RLC) filter in mitigating hazardous overvoltage resulting from transients. The proposed methodology entails using standard RLC filter to suppress transients and its associated overvoltage risks. Through a series of MATLAB/Simulink simulations, the research emphasizes the practical effectiveness of this technique. The study examines the impact of transients under varied operational scenarios, including no-load switching conditions, temporary short-circuits, and load on/off events. The primary aim of the article is to assess the viability of using an established technology to manage system instabilities upon the energization of a CCS under no-load circumstances or in case of a short-circuit fault occurring on the primary side of the CCS distribution transformer. The findings underscore the effectiveness of conventional RLC filters in suppressing transients induced by the CCS no-load switching.
文摘Active power filter (APF) using novel virtual line-flux-linkage oriented control strategy can not only realizes no phase-locked-loop (PLL) control, but also achieves a good inhibitory effect to interfere. However, there are some problems in the conventional method, such as the error of amplitude, the shift of phase angle and the non-determinacy of initial oriented angle. In this paper, two one-order low-pass filters are adopted instead of the pure integrator in the virtual line-flux-linkage observer, which can steady the phase and amplitude. Furthermore, an original scheme of harmonics detection under the rotating coordinate is advanced based on the simplified space vector pulse width modulation (SVPWM) strategy. Meanwhile, by using the new SVPWM algorithm, the voltage space vector diagram of the three-level inverter can be simplified and applied into that of two-level inverter, and this makes the control for Neutral Point potential easier.
文摘Power line(PL)interference is one significant artifact in electrocardiography(ECG)that needs to be reduced to ensure accurate recording of cardiac signals.Because PL interference is non-stationary and has varying frequency,phase,and amplitude in ECG measurement,adaptive techniques are often necessary to track and cancel the interference.In this paper we present a phase-locked loop(PLL)-based adaptive filter to cancel PL interference.The PLL obtains the reference signal that is fed into the adaptive filter to remove the PL interference at the central frequency of 50 Hz.It is found that the technique can effectively cancel PL interference in real ECG signals and,when compared with some existing techniques such as least mean squares(LMS)adaptive filter,the new technique produces better results in terms of signal-to-interference ratio(SIR).
文摘Two methods for improving the equidriving power-frequency characteristics of broad-band high power klystrons are presented. One is that a comb-line bandpass filter with someattenuation properties is inserted between the TWT driver and the klystron for compensatingthe gain-frequency characteristics of the klystron to get the required equidriving power-frequencycharacteristics. The other is that a reactive element is connected with the input cavity to changeits resonance frequencies f<sub>0</sub> and Q<sub>L</sub>, and thus to improve the power-frequency characteristics ofthe klystron.
文摘机载激光雷达(Light Detection and Ranging,LiDAR)技术作为一种能够在短时间内高效获取地面点云数据的新型测绘技术,目前已经在三维地表模型重建、电力巡检中发挥着重要的作用。为了更加有效地实现电力线测绘,本文设计并实现了基于机载LiDAR点云数据的电力线提取与重建方法。首先,通过改进形态学滤波法实现地面点与地物点分割,并通过高差阈值实现电力线点粗提取;其次,对粗提取电力线点进行栅格化处理与拟合残差计算,将计算结果与临界阈值对比实现电力线候选点集的提取;最后,通过双重K-means算法以及RANSAC算法实现单根电力线的提取与重建。使用福建北电南送特高压交流输变电工程中实测的部分机载LiDAR点云数据进行实验,结果表明:本文提出方法对电力线候选点集提取正确率在98%以上,较传统方法正确率更高,验证了本文电力线提取方法的有效性与优越性。
