Harmonic Contribution Determination Research Articles

Comparison of Methods for Determining Harmonic Distortion Contributions Using the IEEE Benchmark Test System

The growing use of nonlinear devices has raised the harmonic levels in power systems. A challenging power quality problem is determining how much each installation contributes to the harmonic voltages measured at a point of common coupling so that the costs of mitigation solutions can be fairly divided. Currently, there is still no practical worldwide established method to solve this problem. The IEEE PES Task Force on Harmonic Modeling and Simulation developed a Benchmark Test System to support this line of research. Therefore, this study uses the IEEE PES Benchmark to evaluate and compare harmonic contribution determination (HCD) methods. To do so, this Benchmark Test System was implemented in MATLAB/Simulink and used to test five HCD methods proposed in the literature under different network operating cases, including cases with background distortions and resonance. The methods are the Voltage Harmonic Vector Method, the IEC Method, the Dominant Impedance Method, the Capacitor Switching Method, and the Harmonic Current Injection Method. It has been found that the HCD methods generally led to similar contribution percentages, proving the convergence of the methodologies. In addition, an analysis of the methods' sensitivity to input measurement errors was done.

Harmonic modeling and harmonic contribution determination: A case study of industrial power supply system

Harmonic modeling and harmonic contribution determination: A case study of industrial power supply system

Multi-point harmonic contribution determination considering multicollinearity of measurement data

Harmonic contribution determination is the basis for harmonic mitigation. To reach this goal, a well-known solution is to utilize the linear regression based methods. This paper scrutinizes this technique and points out a potential problem which may encounter in field applications: the multicollinearity between harmonic measurements. Multicollinearity could lead to unreliable estimated harmonic contributions of traditional methods. For example, linear loads may take on great harmonic contributions and the estimated contributions of harmonic sources are quite different from the exact values. Aiming at this problem, this paper proposes a harmonic contribution determination method based on elastic net regression. This method can reduce the singularity of the measurement matrix and filter out highly correlated data by introducing constraints to solve the ill-conditioned problem caused by multicollinearity. The methodology is verified through both simulation and field data. Comparative experiments and sensitivity studies are conducted to address some practical considerations. The results demonstrate the effectiveness and superiority of the proposed method in different scenarios.

Determination of harmonic contributions using active filter: Theoretical and experimental results

The nonexistence of a methodology feasible in practice to determine the responsibilities (contributions) of a customer and the utility on harmonic voltage distortions at the Point of Common Coupling (PCC) of these systems is a serious problem when there are violations of harmonic voltage limits, since it is impossible to define the participation in expenses with the adoption of mitigating measures (e.g., filter installation). To solve the problem, this paper proposes a methodology for determining these responsibilities. Its development is based on the performance of active filters and meters (voltage and current) connected to the PCC (or in its vicinity). The computational simulation of the methodology was applied to all cases of the IEEE Benchmark System, proving its validity and effectiveness. In addition, a laboratory circuit specially designed and with characteristics like those of real systems allowed its experimental validation, since in this controlled environment the quantities of interest that should be reproduced by the methodology could be accurately determined. One of its important characteristics is the possibility of verifying whether the adopted hypothesis for the validity of its application has been met.

Harmonic contribution determination based on change‐point monitoring and shape context algorithm

In the power system, the harmonic is one of the important concerns of power quality, which has a significant impact on the safe operation of power grids and the energy efficiency for users. When there are not enough special harmonic monitoring devices installed on public transport, it is important to identify the harmonic source and assess the harmonic contribution based on the load data of the user's electricity meter. This paper proposes a data selection and matching idea based on change-point monitoring (CPM), canonical correlation analysis (CCA) and dynamic adjusted shape context (DASC) for determining the harmonic contributions of individual customers and utilities. In the proposed approach, the CPM is used to select the valuable data by detecting the violent fluctuation area of harmonic voltage and the DASC to determine the harmonic contribution of individual customers by matching the user load sequence and harmonic voltage sequence based on CCA, filtering the harmonic contribution from the utility side. Simulation data is used to evaluate the performance of the method and a real-world case study is also conducted. It is found that the proposed technique can be used to reveal the harmonic impact of the loads if data is selected resonably.

A Benchmark Test System to Evaluate Methods of Harmonic Contribution Determination

Harmonic distortions at a point of common coupling (PCC) are caused by the harmonic sources in both supply system and customer facilities. In order to verify compliance with harmonic limits for an operating facility, it is essential to determine the contribution of a facility to the harmonic distortions measured at the PCC. Over the past many years, a significant amount of research work has been conducted in developing different harmonic analysis methods and especially harmonic contribution assessment methods. A common need of this line of research is consistent test systems that can be used to verify/validate a proposed method or to compare different approaches. To address this gap, a benchmark test system representing a typical medium-voltage/low-voltage network supplying industrial loads is proposed in this paper. This paper also includes examples on how to use the system to assess the performance of harmonic contribution determination methods.

Multi-Harmonic Sources Harmonic Contribution Determination Based on Data Filtering and Cluster Analysis

Accurately determining power consumer harmonic contribution determination is an effective method to solve power quality disputes and alleviate harmonic pollution of power grids. This paper proposes a multi-harmonic sources harmonic contribution determination algorithm based on data filtering and cluster analysis. Aiming at the problem of background harmonic fluctuation, this paper uses the cross-approximation entropy (CAE) algorithm to filter the effective data segments of the harmonic voltage and current at the point of common coupling (PCC) to avoid the interference caused by background harmonics. For the problem of harmonic impedance changes of system, using the density-based spatial clustering of applications with noise (DBSCAN) clustering algorithm to detect the harmonic impedance changes of the system. The harmonic contribution under different system harmonic impedance is calculated based on the data of each class cluster. The accuracy of the proposed method is improved compared with existing methods. The experimental analysis demonstrates the effectiveness and superiority of the algorithm.

Harmonic pricing in power systems based on identifying the appropriate contribution of customers

Today, with the restructuring of the power systems, it is possible to implement a program, such as the demand response for the harmonic issues, and use customers to reduce the harmonic level of the network. In this study, a new method is presented based on harmonic pricing to control the harmonic level of the network. Given the fact that the power system is usually infected by the background harmonics, the basis for pricing is the harmonic contribution determination in order to impose a fine fair on the customers. Usually, the determination of the harmonic contribution at each harmonic order is done separately; therefore, a new index is presented, to sum up, the dominant orders in determining the harmonic contribution. This can provide an appropriate impression of the harmonic emission level at the point of common coupling. Simulation results on the standard IEEE 14-bus network show that customers are encouraged to control their harmonic level with a fair harmonic pricing, otherwise, the independent system operator can install harmonic filters at appropriate buses, using the fines received from the customers.

A Method for Harmonic Sources Detection based on Harmonic Distortion Power Rate

Harmonic sources detection at the point of common coupling is an essential step for harmonic contribution determination and harmonic mitigation. The harmonic distortion power rate index is proposed for harmonic source location based on IEEE Std 1459-2010 in the paper. The method only based on harmonic distortion power is not suitable when the background harmonic is large. To solve this problem, a threshold is determined by the prior information, when the harmonic distortion power is larger than the threshold, the customer side is considered as the main harmonic source, otherwise, the utility side is. A simple model of public power system was built in MATLAB/Simulink and field test results of typical harmonic loads verified the effectiveness of proposed method.

Partially linear model for harmonic contribution determination

Harmonic contribution determination is the premise on which the improvement of power system harmonic management is based. Calculating the harmonic impedance accurately is the key issue in harmonic contribution determination. The fluctuation method is a mature method for calculating the harmonic impedance in engineering applications. However, this method is ineffective when the background harmonic fluctuation is dominant. To make up the deficiency of the fluctuation method, the partial linear regression model for the harmonic impedance calculation is proposed in this paper, and then a two‐stage method is derived for the unbiased estimation of the model. The method proposed in the paper can calculate the harmonic impedance whether or not the background harmonic fluctuation is dominant, and then the harmonic contribution can be determined. The effectiveness of the proposed method is verified by the IEEE14‐bus system simulation and field test. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Determining Harmonic Contributions Based on Reweighted Complex Least Squares Method

Determining harmonic contribution quantitatively at the point of common coupling is an important task for power quality management. Outliers and influential points could have strong influences on regressors. This paper puts forward a method named reweighted complex least squares to eliminate or reduce the influences to ensure the robustness of the regression. The method can improve precision of the equivalent harmonic impedance and it can get a more reasonable result in harmonic contribution determination than previous methods. A case study based on the IEEE 14-bus test system was conducted, which shows the validity of the proposed method.

Managing the responsibility for harmonic distortion in power networks

A method to manage the responsibility for harmonic distortion is presented in this paper. The method can determine the contributions to harmonic distortion at the point of common coupling between a customer and a utility. The proposed approach is based on network representation with the Norton equivalent circuits where customer and utility sides are represented with the reference impedance and an equivalent harmonic source. Resistance is introduced as the customer side reference impedance. With this approach any customer deviation from the ideal resistance can be penalized, for example, according to an incentive based scheme. The resistance value is calculated directly from the measurement data. The presented method allows real-time harmonic contribution determination without knowing the actual harmonic customer impedances and enables the evaluation and diagnostic for harmonic distortion also in resonance conditions that cause an amplification of harmonics.

Harmonic Contributions Evaluation With the Harmonic Current Vector Method

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A method to evaluate harmonic contributions at the point of common coupling is presented in this paper. The proposed approach is based on the harmonic current vector method where reference impedances are introduced. Resistance defined at fundamental frequency with measurements is used as the customer-side reference impedance. The presented method allows calculation of harmonic contributions without knowing the actual customer impedances. It also enables better evaluation of the customer and utility harmonic contributions in resonance conditions. The method is verified through a simulation study and with extensive field measurements. Long-term measurements are proposed for determination of harmonic contributions. </para>