Harmonics estimation in emerging power system: Key issues and challenges

Introduction to Variance Estimation (2nd ed.)

Harmonic, which is becoming more and more important day by day in the emerging power system, is one of the most critical power quality parameters. In this paper, the estimation of signal parameters via rotational invariance technique (ESPRIT)-based method is proposed with an accurate model order (the number of frequency components) estimate for power system harmonic and interharmonics detection. It is demonstrated that, even for high noise signal, the proposed algorithm is able to accurately estimate the number of frequency components present in the signal. The proposed method is capable of estimating the accurate values of frequency, amplitude, and phase angle of the distorted current or voltage signals for a wide range of sampling frequency and measurement noise. The robustness of the proposed method has been tested on several simulated synthetic signals and measured experimental signals for different nonlinear loads.

Exact Model Order ESPRIT Technique for Harmonics and Interharmonics Estimation

Fully automated registration of 3D data to a 3D CAD model for project progress monitoring

Power components definitions contained in the IEEE Standard 1459-2000 for unbalanced three-phase systems with nonsinusoidal situations are represented in the frequency domain based on Fourier transform (FT). However, FT suffers from the high computational effort especially when the number of phases increases and it is unable to provide information concerning time content because it provides only an amplitude-frequency spectrum. On the other hand, the discrete wavelet transform (DWT) preserves both time and frequency information while reducing the computational effort through dividing the frequency spectrum into bands and thus overcomes the limitations of FT. In this paper the three-phase power components definitions contained in the IEEE Standard 1459-2000 are reformulated using the DWT and thus redefined in the time-frequency domain. Also in order to study system unbalance, the concept of symmetrical components is defined in the wavelet domain. The results obtained from applying the IEEE Standard definitions and the DWT-based definitions to balanced and unbalanced three-phase systems under nonsinusoidal operating conditions, indicate that the DWT-based definitions are very accurate and the problem of spectral leakages can be reduced by suitable choice of the mother wavelet and the wavelet family. The DWT-based definitions are useful in studying nonstationary waveforms.

Reformulating Three-Phase Power Components Definitions Contained in the IEEE Standard 1459–2000 Using Discrete Wavelet Transform

A self-synchronized ADALINE network for on-line tracking of power system harmonics

Detection of Induction Motor Broken Bar Fault Through Envelope Analysis Using Start-Up Current

A novel digital signal processing algorithm for online estimation of the fundamental frequency of the distorted power system signals is presented. The basic algorithm relies on the development of an efficient variance reduction algorithm; and design of a new stable bandpass infinite impulse response (IIR) second-degree digital integrator (SDDI) with reduced approximation error. Compared with the well-established technique such as the enhanced-phase-locked-loop (EPLL) system, the proposed algorithm provides the following: 1) higher degree of immunity and insensitivity to harmonics and noise and 2) faster response during step frequency change. Structural simplicity, wide range of application, controls over speed and accuracy, and parameter robustness are other salient features of the method. The only limitation as compared with the EPLL system is its slower transient response during step change in signal magnitude. Based on simulation studies, performances of the proposed algorithm at different operating conditions have been presented, and its accuracy and response time have been compared with the EPLL systems.

Bandpass Second-Degree Digital-Integrator-Based Power System Frequency Estimation Under Nonsinusoidal Conditions

Power factor monitoring is an important challenge in deregulated environment to maintain quality in delivered power as well as tariff assessment. In this paper, a unique power factor measurement method has been proposed that can measure the instantaneous power factor of a non-sinusoidal single-phase system accurately at every sample instant. The wavelet transform (WT) has been utilized for multiresolution analysis (MRA) of current waveform. The scheme has been implemented in real time with a Texas Instruments (TI) TMS320VC5416 digital signal processor (DSP) along with data acquisition system card PCI-02. The result has been found to be satisfactory.

A novel instantaneous power factor measurement method based on wavelet transform

Errors may creep in when measuring power by conventional methods due to the inductance and capacitance of the coils and the induced eddy current in the metal parts of the instruments through the alternating magnetic field of the current coil. Apart from these, if a fault occurs in any of the potential transformer secondary circuits or the potential coil of the measuring equipment, a conventional meter cannot detect it, which results in underregistration. In this paper, a microprocessor-based threephase real, reactive, and apparent power measurement system is developed, which displays the power being fed to a load under both normal and faulty conditions. The microprocessor provides a simple, accurate, reliable, and economical solution to these problems. A framework of the hardware circuitry and the assembly language program for the evaluation of power values is given, and the problems to which attention should be paid to execute the proposed algorithm using the microprocessor are discussed. Illustrative laboratory test results confirm the validity and accurate performance of the proposed method in real-time.

Arghya Sarkar

Papers

A self-synchronized ADALINE network for on-line tracking of power system harmonics

Detection of Induction Motor Broken Bar Fault Through Envelope Analysis Using Start-Up Current

Bandpass Second-Degree Digital-Integrator-Based Power System Frequency Estimation Under Nonsinusoidal Conditions

A novel instantaneous power factor measurement method based on wavelet transform

A Low-Cost Fault-Tolerant Real, Reactive, and Apparent Power Measurement Technique Using Microprocessor