Jianmin Li

Hunan Normal University · Department of Engineering and Design

The accurate detection and classification of power quality (PQ) disturbances in power systems is a key step to determine the causes of these events before any proper countermeasure could be taken. This paper presents a new algorithm for detection and classification of PQ disturbances based on the combination of double-resolution S-transform (DRST)...

Dielectric loss factor (DLF) is an important parameter to reflect the insulation condition of a high voltage capacitive equipment, which is widely installed in power systems. Hence, the accuracy of DLF measurement will directly affect the safety and stability of the power grid. This paper proposed a new algorithm based on sampling sequence reconstr...

As the dedicated equipment in electricity measurement, high-accuracy metering is an essential feature of the electronic power meter. In actual measurement, various factors will affect the metering accuracy of energy metering system. Among them, the phase shift introduced by the current transformer is an important cause for the measurement error, es...

In this paper, a fast frequency estimation approach is proposed using frequency-shift filtering. The original sampled signal is first frequency-shifted to 0 Hz nearby via multiplying a reference signal. Then a convolution average filter is applied on the shifted signal to eliminate the spectral interference caused by asynchronous sampling. Finally,...

Voltage sag is one of the most prominent power quality problems in electric power system. Accurate estimation of voltage sag parameters is an important reference for electric utilities and users to evaluate power quality. In this paper, a novel algorithm based on modified S transform with digital prolate spheroidal window (DPSW) is proposed to achi...

The accurate and efficient measurement of flicker severity levels is crucial for evaluating and compensating power system flicker in electric power systems. This paper proposes a simple and fast measurement algorithm for power system flicker severity evaluation. The algorithm utilizes an equivalent measurement model and employs the Hilbert transfor...

The widespread utilization of renewable energy sources can cause serious power quality problems. It presents new challenges for detecting power quality. A deep fractional multidimensional spectrum convolutional neural fusion network (FMSNet) method for automatically identifying and classifying complex PQD signals is proposed in this paper. It inclu...

Fractional-order circuits, which contain fractance devices (L β and C α) described by fractional-order differential equations, are widely used in interdis-ciplinary engineering research. The application of time-domain response (TDR) measurement increases rapidly in analyzing the characteristics of fractance devices and fractional-order circuits. Ho...

The flicker severity level is one of the important indexes of power quality assessment. At present, most flicker detection algorithms are performed under the assumption that the modulation flicker type is known. However, the specific modulation type is difficult to predict in advance, which makes these algorithms severely limited in actual applicat...

Electrocardiogram (ECG) acquisition is easily contaminated by interferences, and denoising is the most important task in ECG detection. Variational mode decomposition (VMD) algorithm is widely used in ECG denoising, which can overcome mode aliasing between intrinsic mode function components existed in the traditional empirical mode decomposition (E...

Early screening is of great significance to reduce the incidence of dysphagia, and accurate recognition of swallowing events (SE) becomes an inevitable step during the screening and treatment of dysphagia. Impedance pharyngography (IPG) has been developed as a promising non-invasive SE detection method in the last 20 years, but the conventional IPG...

Fricke-Morse model is a widely-used 2R-1C equivalent circuit for electrical bioimpedance (EBI) analysis, whose model parameters are usually fitted in multi-frequency (MF) EBI measurements. This paper proposes a novel time-domain fitting method on estimation of the model parameters in single-frequency (SF) sinusoidal complete response (SCR) (the com...

Renewable energy sources will be more vigorously deployed under the global trend of carbon emission reduction. The connection of numerous renewable energy sources poses an increasingly critical challenge to power quality (PQ) issues in power systems. Time-frequency analysis (TFA) is a foundational technique for real-time monitoring and disturbance...

The accurate time-frequency (TF) positioning of power quality (PQ) disturbances is the basis of dealing with PQ problems in power systems. To accurately detect PQ disturbances, this paper proposes a Kaiser window-based S-transform (KST) that provides better time resolution at fundamental frequency to detect the amplitude information for voltage swe...

Objective: The Cole model is a widely used fractional circuit model in electrical bioimpedance applications for evaluating the content and status of biological tissues and fluids. Existing methods for estimating the Cole impedance parameters are often based on multi-frequency data obtained from stepped-sine measurements fitted using a complex non-...

To compare the rock breaking mechanism of the tunnel boring machine (TBM) hob under traditional condition and free-face condition, a series of rock cutting tests and rock cutting simulations of the TBM hob under two cutting conditions are conducted. The rock chip, rock breaking forces and rock breaking efficiency etc. are investigated in this study...

Harmonic is one of the most prominent power quality problems in the power system. Accurate estimation of harmonic parameters is an important reference for electric utilities and users to evaluate power quality. In this paper, a new window named Slepian and Nuttall mutual convolution window (SNMCW) is proposed. The SNMCW is constructed through the m...

The ratio errors of resistance divider network and current transformer, and the phase error introduced by current transformer, which are the main error sources, greatly affect the measurement accuracy of actual electronic energy metering equipment. Because the fairness of energy metering system has a significant influence on the energy market, a di...

Second-order generalized integrator (SOGI)-based phase-locked loops (PLLs)/frequency-locked loops (FLLs) are the most commonly used methods for grid synchronization. While the SOGI in these standard SOGI-PLLs/FLLs is adaptive to the estimated frequency, which results in coupling between the SOGI and PLL/FLL, and this coupling brings about difficult...

Harmonic time-frequency characteristics are the most important foundation for harmonic power flow calculation, harmonic energy meter, and harmonic treatment. However, the existing time-frequency analysis methods have the drawback as either single measuring data or low measuring precision. To address these issues, a digital prolate spheroidal window...

As the nonlinear loads and impact loads in power grid increase, the power quality problems are becoming more and more serious. Accurate and fast detection of power quality disturbance signals has great significance for finding the cause of power quality problems and improving the power quality. Therefore, an algorithm for recognizing power quality...

In numbers of industrial fields, many filtering algorithms of industrial signals, mechanism-based modeling methods and control strategies are based on the hypothesis of white noise. However, some researchers propose that the colored noise is closer to the real noise than the white noise. Then, whether the noise is the white noise, the colored noise...

This paper proposes a new approach for the detection and localization of short duration variations using sliding window singular value decomposition (SVD) and sparse signal decomposition (SSD) on over-complete dictionary. In order to solve the problem of high computational complexity in SSD, the estimated frequency is obtained firstly by using fast...

The kiln head temperature (KHT) is a key thermal variable to condition monitoring and stable control of the rotary kiln. In this paper, a hybrid dynamic prediction framework (HDPF) is proposed to realize the accurate online prediction of the KHT chaotic time series of the rotary kiln. Where, in order to response time-delay and time-varying behavior...

The pre-cutting machine is becoming valued due to its ability to effectively prevent surface settlement and reduce vibration in tunnel construction. To obtain the cutting characteristics and layout of pre-cutting machine cutter, the cutting tests by the pre-cutting machine cutter are conducted and the cutting laws are also studied. The research res...

A remote calibration method of measurement error of smart meter, which has the characteristics of large quantity and difficult calibration one by one on site, is studied in this paper. First of all, we introduce the principle of estimation the measurement error of smart meter by using a large number of data collected by smart meter to the informati...

Objective: The Fricke-Morse impedance model is widely used in bioelectrical impedance analysis (BIA), which is usually fitted by multi-frequency electrical impedance data. Here, we propose a novel numerical method for estimating the model parameters using single-frequency sinusoidal excitation. Approach: A singlefrequency sinusoidal signal is used...

Objective: The Cole model is widely used in bioimpedance spectroscopy (BIS) applications for evaluating the contents and status of biological tissues. Traditional frequency-domain fitting methods for Cole parameter estimation (CPE) often need wideband direct or indirect BIS measurements. The newly emerged time-domain fitting methods do not require...

In order to measure dielectric loss angle (DLA) accurately, and overcome the defects caused by fundamental frequency fluctuation, sampling rate, word length of the analog-to-digital converter, and noise, a dielectric loss angle measurement algorithm based on sequence reconstruction is proposed in this paper. Firstly, the fundamental frequency is es...

为实现较高的时频能量聚集，实现谐波时频参数准确辨识，提出一种新的谐波时频分解方法——K-S分解, 依据FFT→Kaiser窗→IFFT思路，推导K-S分解算法；K-S分解获得的二维复数时频矩阵的列向量表征被测信号某一采样时刻的幅值相位随频率变化，行向量表征被测信号某一频率的幅值相位随时间变化的分布，据此获得被测信号的幅值、频谱、时间及相位特征信息，实现信号的自适应时频分析；复杂电网信号的谐波时频辨识仿真实验验证了K-S分解的可行性与自适应能力。

Wideband current sources that can work stable over a wide frequency range with large load variations are critical for the performance of electrical impedance spectrum (EIS) measurements. In this paper, we design a wideband mirrored current source (MCS) using two simple differential difference amplifiers (DDA) AD830. PSpice simulation and measuremen...

Since the frequency fluctuation exists the actual power system which makes the strictly synchronous sampling condition can hardly meet, the frequency and other parameters of the power system are difficult to accurately measure. To deal with this problem, a novel frequency measurement algorithm based on frequency shift and filtering is proposed by t...

In order to solve the problem of time consuming, large energy consumption and low detection efficiency of loss on drying method, a predictive method for moisture content detection is designed and implemented. This proposed method uses the characteristics of infrared drying and water loss process. The mathematical model of drying curve is establishe...

Due to conventional differential evolution algorithm is often trapped in local optima and premature convergence in high dimensional optimization problems, a State Evaluation Adaptive Differential Evolution algorithm (SEADE) is proposed in this paper. By using independent scale factor on each dimension of optimization problem, and evaluating the dis...

Bioimpedance spectroscopy (BIS) measurement is widely used in various biological medical applications. Broadband excitation signals with sparse spectra can be beneficial to increasing the signal-to-noise ratio (SNR) and decreasing the time of BIS measurements. This study introduces a rapid synthesis method to generate near-binary multisines (NBMs)...