Harmonic Source Identification Research Articles

On the Dominant Harmonic Source Identification—Part II: Application and Interpretation of Methods

This two-part paper presents the review, application, and interpretation of the methods for analyzing the harmonic distortions at the point of common coupling thoroughly. In Part I, two different definitions for the dominant side are discussed regarding the equivalent harmonic “voltage” or “current” source. In addition, common methods are categorized in three general concepts based on the direction of active power flow, the reactive power, and the voltage–current ratio. These three categories as well as their validity are analytically reviewed for both the definitions. In Part II, the application of the methods is illustrated using two common calculation examples. The magnitude and the phase angle of the equivalent harmonic sources are separately varied in the first and second calculation example, respectively. The validity of the methods is investigated using these calculation examples. Afterward, the physical interpretation of the methods is addressed. The difference between the dominant sides regarding the equivalent harmonic “voltage” and “current” source is discussed using the calculation examples. It is shown that if one of the utility and customer equivalent harmonic voltage sources is “much” larger than the other, the dominant sides regarding the equivalent harmonic “voltage” and “current” source will be the same. Some practical aspects such as the tolerance of the methods to errors in input data are discussed. In this regard, nonresonance and resonance conditions are taken into account. This two-part paper provides a comprehensive but clear review of methods for identifying the dominant side.

Harmonic Load Diagnostic Techniques and Methodologies: A Review

<p>This paper will review on the existing techniques and methodologies of harmonic load diagnostic system. The increasingly amount of harmonic producing load used in power system are the main contribution in quantifying each harmonic disturbance effects of the multiple harmonic producing loads and it became very important. Literature proposes two different techniques and methods on the harmonic source identification under the soft computing technique classification. The advantages and disadvantages of harmonic load identification techniques and methods are discussed in this paper. In the proposed method, the issue on the harmonic contribution is determine and transformed to a data correlation analysis. Several techniques to identify the sources of harmonic signals in electric power systems are described and reviewed based on previous paper. Comparative studies of the methods are also done to evaluate the performance of each techniques. However, without sufficient information in this inconsistent environment on the property of the power system, accurate harmonic producing load diagnosis methods are important and further investigations in this regard assumes great implication.</p>

Method of Harmonic Source Identification Based on Harmonic Apparent Power

Based on the harmonic apparent power defined by the IEEE 1459-2010 power standard, the paper proposed a new method of identifying the main harmonic source at the point of common coupling (PCC). Using the reference impedance method, the utility and customer harmonic voltage and current contributions are calculated. And then combined with the IEEE 1459-2010 standard, defined the harmonic apparent power caused by the independent action of the equivalent harmonic source on the system side and the user side, by directly comparing the size of the two to determine the location of the main harmonic source. The method can consider the comprehensive influence of harmonic voltage and harmonic current, then identify the main harmonic source at PCC point. Finally, the rationality of the method is verified by the simulation of the IEEE 13 node system.

Harmonic source identification in distribution system using estimation of signal parameters via rotational invariance technique-total harmonic power method

With proliferation of power electronics devices in the distribution system, harmonic distortion has become one of the major power quality (PQ) problems. In evolving the liberalized electricity market, it becomes necessary to develop suitable methods to allocate the responsibilities for the harmonic distortion to improve the PQ. This paper presents a new technique for harmonic source identification, which is based on total harmonic power (THP) method using estimation of signal parameters via rotational invariance technique (ESPRIT). Traditionally, harmonic powers for THP method is computed using Fourier transform, which inherits serious drawbacks of the discrete and fast Fourier transform, namely, inaccuracy owing to poor spectral resolution, spectral leakage, and so forth. Simulation results have been presented for different distribution system configurations and conditions, which confirms the improved capabilities of the proposed method in harmonic source identification.

Comprehensive identification of multiple harmonic sources using fuzzy logic and adjusted probabilistic neural network

This paper presents a comprehensive approach based on fuzzy logic and probabilistic neural network (PNN) to identify location, relative level, and type of multiple harmonic sources in power distribution systems. The location and relative level of harmonic sources were determined in the fuzzy stage by interpreting harmonic powers together with network impedances. Then, the type of the harmonic sources was classified in the neural stage using adjusted PNN. In the proposed method, the harmonic powers were considered as classification features. Then, ReliefF feature selection method was used to reduce the redundant data and dimension of features vector. A new modified adaptive imperialist competitive algorithm (MAICA) was proposed to determine the only adjusted parameter of the PNN classifier. Furthermore, a deep belief network (DBN) was applied in the neural stage, and its results were compared with the PNN classifier. The proposed approach was evaluated on IEEE 18-bus and IEEE 69-bus test systems. Unlike the single point methods, the presented method provides information on multiple harmonic sources in the whole of the distribution system. The results show that the comprehensive approach identifies the multiple harmonic sources with high accuracy.

Harmonic source identification in distribution system using non-active power quantities

A new method to identify the location of the harmonic generating sources in a distribution network has been proposed in this paper. The method is based on the wavelet decomposition of voltage and current signals at the point of measurement. Three non-active power quantities have been chosen which can represent only the harmonic components present in the system. The exact location of the dominant harmonic generating source can be found out with the help of the chosen non-active powers. The effectiveness of this method is studied on a three phase radial distribution system. It has been shown through different case studies that the proposed strategy is very effective in locating harmonic source present either in upstream or downstream of the metering section.

Harmonic source identification in distribution system using non-active power quantities

Harmonic source identification in distribution system using non-active power quantities

An Improved of Multiple Harmonic Sources Identification in Distribution System with Inverter Loads by Using Spectrogram

This paper introduces an improved of multiple harmonic sources identification that been produced by inverter loads in power system using time-frequency distribution (TFD) analysis which is spectrogram. The spectrogram is a very applicable method to represent signals in time-frequency representation (TFR) and the main advantages of spectrogram are the accuracy, speed of the algorithm and use low memory size such that it can be computed rapidly. The identification of multiple harmonic sources is based on the significant relationship of spectral impedances which are the fundamental impedance (Z1) and harmonic impedance (Zh) that extracted from TFR. To verify the accuracy of the proposed method, MATLAB simulations carried out several unique cases with different harmonic producing loads on IEEE 4-bus test feeder cases. It is proven that the proposed method is superior with 100% correct identification of multiple harmonic sources. It is envisioned that the method is very accurate, fast and cost efficient to localize harmonic sources in distribution system.

Wavelet-based technique for identification of harmonic source in distribution system

SUMMARY A new method to identify the location and nature of the harmonic generating sources in a distribution system has been proposed. The method is based on wavelet decomposition of voltage and current signals at the point of measurement. Detail reactive power at level 1 of wavelet decomposition has been used. A harmonic generating load is identified by extracting its characterizing harmonics in the power system signals. The pseudo-frequency for the wavelet decomposition at level 1 is set at the characteristic frequency of the load, and the sampling frequency is so chosen that the desired harmonic information can be extracted at the detail level 1. Power systems signals are, however, captured at a higher sampling frequency. For the identification of the disturbing source, the required sampling frequency for level 1 decomposition is obtained using downsampling on the captured data. Applicability of the method has been demonstrated for both radial and non-radial power system networks.

A dynamic approach to identification of multiple harmonic sources in power distribution systems

This paper provides a novel algorithm for identifying harmonic sources in power distribution systems. This algorithm is developed based on an observer design to carry out harmonic estimation for a combination of suspicious nodes. The estimation error is analyzed to determine the existence of harmonic sources in the specified node combinations. This approach is used to determine the source of both single and multiple harmonic sources in distribution systems with time varying load parameters. For systems with a large number of suspicious nodes, the system may be divided into sub-systems and the algorithm is applied to each sub-system to identify the harmonic sources present. Simulations are carried out on a benchmark IEEE distribution test feeder for both single and multiple harmonic sources and a number of scenarios are simulated to verify the accuracy and robustness of the proposed approach. The results show that the node combinations which represent the harmonic sources yield an estimation error which approaches zero asymptotically.

Determining true harmonic contributions of sources using neural network

This paper proposes exact radial basis function neural network (ERBFN) to identify the harmonic sources and their contributions at the point of common coupling without disconnecting the load from the network. The main advantage of the method is that only waveforms of voltages and currents have to be measured. This method is applicable for both single and three phase loads. Comparisons are made with the different types of neural networks such as feed forward back propagation neural network (FFBPN), cascade feed forward back propagation network (CFBPN) and radial basis function neural network (RBFNN) to verify the accuracy of the proposed method in harmonic source identification. Results proved that the identification of harmonic source at the point of common coupling using proposed method is more accurate with less computational time when compared to the other neural network structures.

Identification of Harmonic Sources in Electrical Power Systems using State Estimation with measurement error

In this article we show that the Total Harmonic Distortion (THD) of the current is a reliable index to identify the location of harmonic sources in a power system. It is proved that the harmonic estimators fail to identify harmonic source measurement errors. A 14 node system with two sources of harmonic solved by two methods is tested.

Identification of Multiple Harmonic Sources in Power System Using Optimally Placed Voltage Measurement Devices

This paper presents an effective methodology to identify the multiple harmonic sources along with their harmonic injection levels in a power system using optimally placed harmonic measurement devices (HMDs). Binary particle swarm optimization is used to find the optimal locations of HMDs to collect harmonic data. The proposed harmonic identification approach is based on the direction of harmonic power flow at system nodes to categorize and rank the suspected buses. The method is simple and can be used for locating the multiple harmonic sources in the presence of load modeling errors and measurement errors. The effectiveness of the proposed methodology is tested on 18-bus radial as well as nonradial distribution systems under different scenarios.

Fast Harmonic Estimation of Stationary and Time-Varying Signals Using EA-AWNN

Field measurement of harmonic distortion is a fundamental requirement for monitoring, analysis, and/or control of power system harmonics. Fast and accurate estimation of time-varying harmonics is a key to realize many objectives of the smarter and cleaner grid such as harmonic source identification, improved active filter control for mitigation of harmonics, and smart meters for harmonic pollution metering. This paper presents a fast and accurate approach for real-time estimation of moderate time-varying harmonics of voltage/current signals. The proposed method is based on estimation of signal parameters via rotational invariance technique (ESPRIT)-assisted adaptive wavelet neural network (AWNN). The AWNN provides quick estimates (twice every fundamental cycle with only half-cycle data as input) of the dominant harmonics, whereas the ESPRIT complements it to handle time-varying signals with higher accuracy. The salient features of the proposed method are validated on the simulated and experimental signals of stationary and time-varying nature.

A Parameter Identification Method for Helicopter Noise Source Identification and Physics-Based Semiempirical Modeling

A new physics-based parameter identification method for rotor harmonic noise sources is developed using an acoustic inverse simulation technique. This new method allows for the identification of individual rotor harmonic noise sources and allows them to be characterized in terms of their individual non-dimensional governing parameters. This new method is applied to both wind tunnel measurements and ground noise measurements of two-bladed rotors. The method is shown to match the parametric trends of main rotor Blade-Vortex Interaction (BVI) noise, allowing accurate estimates of BVI noise to be made for operating conditions based on a small number of measurements taken at different operating conditions.

Identification of Harmonic Source at the Point of Common Coupling Based on Voltage Indices

Kertas kerja ini membentangkan teknik baru untuk mengesan punca gangguan harmonik, samada pembekal atau pengguna. Dalam kaedah ini, litar–litar setara Norton dan Thevenin diperolehi untuk tujuan pengesanan punca gangguan harmonik. Berdasarkan kedua–dua litar setara tersebut, dua kes telah dianalisa iaitu litar yang mempunyai satu punca harmonik dan litar yang mempunyai dua punca harmonik. Di dalam litar yang mempunyai satu punca harmonik, litar setara diringkaskan kepada litar setara Thevenin untuk memperolehi indeks voltan. Voltan yang diperolehi di titik gandingan sepunya (TGS) dibandingkan dengan voltan di pihak pembekal. Di dalam litar yang mempunyai dua punca harmonik, teorem tindihan dan litar setara Norton digunakan untuk menerbitkan indeks voltan daripada bacaan yang diperolehi di titik gandingan sepunya. Beberapa kes dan ujian suis dijalankan menggunakan perisian PSCAD/EMTDC. Perbandingan dilakukan dengan teknik galangan kritikal (GK) untuk membuktikan kesahihan teknik yang dicadangkan dalam pengesanan punca gangguan harmonik. Keputusan yang diperolehi membuktikan teknik pengesanan punca gangguan harmonik berdasarkan indeks voltan lebih baik daripada teknik galangan kritikal (GK). Kata kunci: Harmonik, teorem tindihan, galangan harmonik This paper presents a new method to determine harmonic source either at the utility or the customer based on voltage indices. In the method, both Thevenin and Norton equivalent circuits are first derived for harmonic source identification. Based on these circuits, two cases are analyzed, that is a circuit with a single harmonic source and a circuit with two harmonic sources. In a single harmonic source, harmonic circuit is simplified to a Thevenin equivalent circuit which is used to derive the voltage indices. The voltage measured at the point of common coupling (PCC) is compared with the voltage at the utility sides. In a two harmonic source system, the superposition theorem and Norton equivalent circuits are employed to derive the voltage indices at utility and customer sides based on the voltage and current measurements at the PCC. For both systems, the voltage index based on the higher voltage magnitude is identified as the main harmonic source. Several case studies and a series switching tests are performed in the simulations using the PSCAD/EMTDC program. Comparisons are made with the Critical Impedance (CI) method to verify the accuracy of the proposed method in harmonic source identificafion. Results proved that the identification of harmonic source at the point of common coupling based on voltage indices is more accurate when compared to the CI method. Key words: Harmonic, superposition theorem, harmonic impedance

Data Mining Applied to Identification of Harmonic Sources in Residential Consumers

This work proposes a method based on both preprocessing and data mining with the objective of identify harmonic current sources in residential consumers. In addition, this methodology can also be applied to identify linear and nonlinear loads. It should be emphasized that the entire database was obtained through laboratory essays, i.e., real data were acquired from residential loads. Thus, the residential system created in laboratory was fed by a configurable power source and in its output were placed the loads and the power quality analyzers (all measurements were stored in a microcomputer). So, the data were submitted to pre-processing, which was based on attribute selection techniques in order to minimize the complexity in identifying the loads. A newer database was generated maintaining only the attributes selected, thus, Artificial Neural Networks were trained to realized the identification of loads. In order to validate the methodology proposed, the loads were fed both under ideal conditions (without harmonics), but also by harmonic voltages within limits pre-established. These limits are in accordance with IEEE Std. 519-1992 and PRODIST (procedures to delivery energy employed by Brazilian's utilities). The results obtained seek to validate the methodology proposed and furnish a method that can serve as alternative to conventional methods.

Determining the Harmonic Impacts of Multiple Harmonic-Producing Loads

Identifying harmonic sources in a given power system is an important task for utility power-quality (PQ) management. This paper presents a new class of harmonic source identification problems: how to quantify the harmonic impact of several known harmonic-producing loads on the harmonic levels observed at a network location. This paper first defines the problem and proposes a harmonic impact index to theorize the problem. This paper then presents a statistical-inference-based method to estimate the index. The data required for this analysis are the harmonic voltage and current magnitudes continuously collected by the existing PQ monitors. The characteristics of the proposed method are investigated through case studies. Finally, additional applications and improvements of the proposed method are discussed.

Power quality state estimation

AbstractDue to the size and complexity of modern electrical power networks and the cost of monitoring and telecommunication equipment, it is unfeasible to fully monitor the system state. For this reason state estimation techniques are used. With strategically placed measurements, estimation techniques can determine the parameters at unmonitored locations. Fundamental frequency state estimation is now a standard tool in modern power systems. The emission and immunity levels of modern electrical equipment are different to that of the past, and this has resulted in power quality issues have become important. Knowledge of the source and location of the disturbances is desirable so that remedial action can be taken promptly. Recent contributions have extended the concept to: harmonic state estimation (HSE) and identification of harmonic sources, transient state estimation (TSE) and voltage sag state estimation (VSSE), which are all types of power quality state estimation (PQSE). This paper provides an overview of the state‐of‐the‐art techniques currently available for PQSE in a large electrical power system. Copyright © 2009 John Wiley & Sons, Ltd.

A Novel Method for Optimal Capacitor Placement and Sizing Based on Harmonic Source Identification in Distorted Distribution Systems

With increasing non-linear loads, harmonic currents are injected into networks that distort all of the voltages and currents. This is an issue that must be considered when making a decision regarding capacitor placement so that resonance will not occur, and therefore losses and severe stress on the network equipment is prevented. In this paper, a new method is proposed based on the harmonic source identification and current separation to cope with non-linear loads in the capacitor placement problem. The intrinsic difference between linear and non-linear loads in their V-I characteristics can be used to model harmonic sources. Also, a genetic algorithm is used to solve the related optimisation problem. To validate the proposed method, an IEEE 33-bus test system is simulated. Based on the simulation results, by using the proposed method, the influence of harmonics is considered properly. Consequently, corresponding savings are increased and also the solution will not cause any resonance.