Harmonic Power Compensation Research Articles

Analysis of the Influence of the 6-Pulse Thyristor-Bridge Input Reactor Size on the Shunt Active Power Filter Work Efficiency: A Case Study

This paper presents a case study in which the influence of the 6-pulse thyristor-bridge input reactor size on the shunt active power filter (SAPF)’s work performance is investigated. The purpose of using an SAPF in the power system is in most cases for fundamental harmonic reactive power compensation, harmonics and asymmetry mitigation. The work efficiency of such a filter depends not only on the designed control system, interface filter and dc-link capacitor parameters, but also on the parameters of the electrical system in which it is connected. Therefore, it is necessary to study and know the power system (supplier and consumer sides) before its installation. For instance, in the electrical system with diode or thyristor-bridge as loads, the SAPF performance efficiency may not be satisfied due to the high rate of current change (di/dt) at the points of commutation notches. In this paper, the performed simulation and laboratory experiments show that for a better operating efficiency of the SAPF, the input reactor parameters should be selected based not only on the effective reduction in the inverter switching ripple or the control system demand, but also on the parameters of the load, such as the parameters of the diode or thyristor-bridge input reactor. Apart from the experimental demonstrations on how the input reactor size influences the SAPF work efficiency, the novelties in this paper are: the formulated recommendations on how to choose the SAPF input reactor parameters (the SAPF is more efficient in terms of harmonics, asymmetry and reactive power mitigation when the inductance of its input reactor (L-filter) is smaller than the one of the diode or thyristor-bridge input reactor); the proposed SAPF control system; the proposed expressions to compute the SAPF input reactor inductance, DC voltage and capacitor.

Performance Evaluation of Various Filters for Electric Arc Furnaces Harmonic and Reactive Power Compensation

Performance Evaluation of Various Filters for Electric Arc Furnaces Harmonic and Reactive Power Compensation

Super-twisting Sliding Mode Control for a Multifunctional Double Stage Grid-connected Photovoltaic System

This paper proposes a super-twisting sliding mode control for a multifunctional system that includes a Photovoltaic (PV) system connected to the grid through the Active Power Filter (APF). The latter is implemented to improve the power quality in the grid side, and injecting the provided photovoltaic power into the grid. Sliding mode control is known as a powerful control with good performance in transient and steady-state conditions. In this work, a Super-Twisting Sliding Mode Control (ST-SMC) is applied to extract the maximum power from the PV source, corresponding to the irradiation level, as well as to the three-phase inverter-based-APF power control. For the system to inject the generated power from the PV source into the grid with respect to the international standards, fulfilling the active power filtering, synchronous reference frame theory is used to generate the appropriate reference signals for harmonic and reactive power compensation. To test the multi-functionality of the system (PV-APF), this one is connected to a grid supplying nonlinear loads that absorb non-sinusoidal currents. Through the simulation results, it has successfully achieved the multi-functionality of the proposed system under steady-state and dynamic conditions. The results also show the effectiveness and moderation of the proposed super-twisting sliding mode control. Furthermore, a comparative study has been established over the conventional PI controller, showing the clear superiority of the proposed control in every aspect.

A Novel Integrated Method for Harmonic Suppression and Reactive Power Compensation in Distribution Network

Aiming at the serious harmonic pollution and the low power factor in the distribution network of industrial enterprises, this paper develops an integrated method for harmonic suppression and reactive power compensation suitable for the distribution network of industrial enterprises. The integrated method realizes the dual functions of harmonic filtering and reactive power compensation, and filters out the harmonic current to get a symmetrical current waveform while ensuring safe operation of the power compensator. In addition, it solves the problems of high harmonic content, small power factor in the distribution network, and device burnout caused by direct input of reactive power compensator. The main contributions of this paper are as follows: (1) According to the demand for the integration of harmonic suppression and reactive power compensation, the steps of integrated method for harmonic suppression and reactive power compensationare proposed, and then the methods for harmonic filtering and reactive power compensation are investigated; (2) a method for designing the capacity of a filter capacitor and the rated parameter of an electromagnetic coupling reactance converter is proposed, and an optimization simulation system is constructed to design the parameters of the filter; (3) a simulation system is developed, followed by parameter design and simulation analysis of harmonic filtering subsystem (HFSS), reactive power compensation subsystem (RPCSS) and the integrated system of harmonic suppression and reactive power compensation. Simulation results verify that the HFSS is put into operation first and then switched off later to ensure the normal operation of other equipment in the distribution network. After the treatment, the power factor, harmonic current content and total distortion rate all meet the national standards. The integrated method can dynamically track harmonics and reactive power changes, filter out harmonics, improve power factor and the symmetry level of the power source, and ensure the normal operation of other equipment in the distribution network. The research results lay a certain theoretical and technical foundation for the harmonic filtering and reactive power compensation theory, technology and its device innovation to achieve effective suppression of power harmonics and reactive power compensation.

하이브리드 능동전력필터의 전력품질 개선을 위한 Coordinate Transformation 기법에 대한 성능 비교

In this paper, the performances of Coordinate transformation method for harmonic and reactive power compensation of hybrid active power filters were compared and analyzed. Recently, as the spread of power electronic devices is expanding, the occurrence of harmonics in the system is increasing, and the harmonics have a bad effect on the system and electrical equipment. As a measure against such harmonics, the parallel resonance problem of passive power filters among filters can be solved, and a hybrid active power filter with a small compensation capacity of the active power filter can be considered. However, In order to control the hybrid active power filter to the required power factor, it is necessary to control it through fast tracking even when the load changes. Therefore, in this paper, the performance was analyzed by applying the p-q theory method and the compensation current control method using d-q respectively to the hybrid active power filter. As a result of comparing and analyzing the effects through simulation, it was confirmed that using the p-q theory method quickly followed the target value with a relatively small error even with a variable load than using the d-q method.

Distribution system power quality compensation using a HSeAPF based on SRF and SMC features

The purpose of this paper is to describe the design of a Hybrid Series Active Power Filter (HSeAPF) system to improve the quality of power on three-phase power distribution grids. The system controls are comprise of Pulse Width Modulation (PWM) based on the Synchronous Reference Frame (SRF) theory, and supported by Phase Locked Loop (PLL) for generating the switching pulses to control a Voltage Source Converter (VSC). The DC link voltage is controlled by Non-Linear Sliding Mode Control (SMC) for faster response and to ensure that it is maintained at a constant value. When this voltage is compared with Proportional Integral (PI), then the improvements made can be shown. The function of HSeAPF control is to eliminate voltage fluctuations, voltage swell/sag, and prevent voltage/current harmonics are produced by both non-linear loads and small inverters connected to the distribution network. A digital Phase Locked Loop that generates frequencies and an oscillating phase-locked output signal controls the voltage. The results from the simulation indicate that the HSeAPF can effectively suppress the dynamic and harmonic reactive power compensation system. Also, the distribution network has a low Total Harmonic Distortion (< 5%), demonstrating that the designed system is efficient, which is an essential requirement when it comes to the IEEE-519 and IEC 61,000–3-6 standards.

Multistep Finite Control Set Model Predictive Control of Photovoltaic Power Generation System with Harmonic Compensation

Photovoltaic (PV) power generation is the main aspect of new energy power generation, and it is an important means to achieve the goal of carbon neutrality. When the PV system is connected to the grid, the nonlinear load of the grid will affect the power quality and consume reactive power. This paper proposes a PV power generation grid-connected system to improve power quality, with an active power filter (APF) function. Through the maximum power point tracking (MPPT) method, PV power generation can operate at the maximum power point and play the function of harmonic and reactive power compensation at the load side. To improve the dynamic performance of the grid-connected PV system and harmonic compensation simultaneously, multistep finite control set model predictive control (FCS-MPC) is adopted for the grid-connected module. The whole system does not need additional equipment, as it plays the role of two devices and effectively reduces the input cost. In this paper, the proposed structure and multistep FCS-MPC are verified in MATLAB/Simulink. The results show that the system injects the maximum power into the power grid at the same time when the load changes and compensates the harmonic generated by the nonlinear load of the power grid so that the total harmonic distortion of the power grid can meet the operation standard, and the system has good dynamic performance and steady-state performance.

RNN based Control Algorithm for Power Quality Improvement in PV Integrated Distribution System

In this paper, a single layer Recurrent Neural Network (RNN) algorithm has been proposed for the control of single-stage three-phase grid integrated solar photovoltaic (PV) system. Voltage Source converter (VSC) has been controlled for overcoming power quality problems in distribution systems viz. harmonic mitigation, active and reactive power compensation, load balancing etc. in three-phase grid connected PV systems. The PV array has been designed such that it delivers maximum power to the grid via VSC. The proposed algorithm has been implemented in MATLAB/Simulink and tested on hardware. Simulation and experimental results have been shown for the verification of the proposed algorithm under steady-state and dynamic conditions. These results conform to standard IEEE-1547 and the harmonics in grid currents are reduced to < 5% for the grid-connected PV system.

Three Phase Shunt Active Power Filter Using Simulink

In AC power grids for harmonic emission reduction and reactive power compensation, activity filters have become very common. The network with non-linear loads such as power converters is equipped with an active power filter for optimizing THD. Shunt type or series type. It also enhances voltage control and unbalance in flicks. For most active control filters, the instantaneous power principle also known as p-q theory is used. This paper explains Shunt active power filter for a 3-phase wire AC network. The proposed shunt active power filter uses principle of instantaneous reactive rower to remove harmonics from source streams. On the Matlab/Simulink method, the simulation results are shown.

Investigation on the Work Efficiency of the LC Passive Harmonic Filter Chosen Topologies

The use of passive harmonic filters (PHFs) in an electrical system is in most cases for the fundamental harmonic reactive power compensation and harmonics mitigation. In comparison to other filters applied to improve the power quality, such as the shunt active power filter or hybrid active power filter, their main advantages are the low investment costs and easy applicability in low-, medium-, and high-voltage electrical systems. However, their installation demands a deep analysis of the electrical system as well as a thorough knowledge of the topology to be installed. Their work efficiency is influenced by the parameters of the electrical system (grid, load, and filter itself) which must be well-known before installation. The aim of this paper is to present an investigation on the work efficiency of the LC passive harmonic filter chosen topologies. The PHFs are investigated in the frequency domain through their impedance versus frequency characteristics as well as in the time domain through an electrical system. A comparative study between filters is also considered. The investigations on the case examples of PHFs are based on simulations and some laboratory studies are also presented.

Reactive power and harmonic compensation in a grid-connected photovoltaic system using fuzzy logic controller

Abstract This work investigates the performance of a single-phase grid-connected photovoltaic (PV) system under non-ideal source voltage conditions using a fuzzy logic controller. The single-phase instantaneous reactive power theory has been modified to explore the harmonic and reactive power compensation with distorted grid voltage excitation while transferring active and reactive power to the grid and the non-linear load. Instead of a traditional Proportional-Integral (PI) controller, the proposed method implements a fuzzy logic controller for the extraction of the reference compensating current. This method is compared with the traditional single-phase instantaneous reactive power theory. The advantage associated with a fuzzy logic controller is that it does not need accurate mathematical modeling of the system, instead, it is based upon the linguistic characterization of the input and output variables. Besides, care has been taken to provide uninterrupted compensation throughout the variation of the solar irradiation level. The proposed method has also been verified through a laboratory-developed prototype using a DS1103 processor.

Coordinated control strategy of UPQC by dynamic collaborative task-solving scheme based on multi-agent system

The conventional unified power quality conditioner (UPQC) includes a series active power filter (SAPF) and a parallel active power filter (PAPF). The former is used for voltage compensation, whereas the latter is used for harmonic and reactive power compensation. Because the SAPF always maintains an idle state, the UPQC function is relatively independent, and its utilization rate is low. To improve the UPQC performance more efficiently, a coordinated control strategy for UPQCs is established using a dynamic collaborative task-solving scheme based on a multi-agent scheme is proposed. First, the dynamic collaborative task-solving scheme based on a multi-agent system is illustrated. Next, the theoretical analysis of reactive power flow in a UPQC is discussed. Considering that no power quality problems such as voltage sag exist on the series side of the UPQC, the SAPF is used for reactive power compensation, and the PAFP is used for harmonic compensation based on the coordinated control strategy. To verify the validity and feasibility of the proposed control strategy, a simulation model is constructed in Simulink. The simulation results demonstrate the feasibility and validity of the proposed coordinated control strategy. The experimental results prove that the SAPF and PAPF can compensate for the reactive power and harmonics, respectively. The proposed strategy can be employed to improve the power quality of the microgrid effectively. Furthermore, it improves the comprehensive compensation performance of UPQCs and provides a new method for engineering applications.

Performing reactive power compensation of three-phase induction motor by using parallel active power filter

Nowadays, the problem of power quality increases day by day. Harmonic current and reactive power are the important factors disturbing the power quality. The induction motors draw both harmonic current and reactive power from the grid. Reactive power and harmonic current lead to heat losses and decrease in the efficiency of the transmission lines. Passive and active filter applications have been used to solve these problems. There are some disadvantages of passive filters. Large physical dimensions and resonance with load can be shown as examples for these disadvantages. Therefore, the application areas of Active Power Filter (APF) are rapidly developing due to the fact that they can be applied together with harmonic and reactive power compensation as appropriate control methods. This paper proposes a MATLAB/Simulink simulation to perform power factor correction and reactive power compensation of three-phase induction motor by using three-phase Parallel Active Power Filter (PAPF). In order to generate PAPF’s reference currents the Sine Multiplication Technique (SMT) is used. Simulation studies are presented to be able to assess the performances under different motor operating conditions. The proposed hysteresis controller based PAPF filter makes the power factor up to 1 and the reactive power compensation of the three-phase induction motor.

Application of fuzzy control harmonic suppression and reactive power compensation technology for power electronic equipment based on cloud computing

Harmonic pollution and reactive power consumption are the two most important factors affecting power quality. Power electronics, as the largest harmonic source, will produce a large number of harmonics while running, and will also lose reactive power, reduce the power factor of the system and affect power quality. Firstly, the current situation of reactive power and harmonic suppression based on fuzzy control is briefly introduced. Then, the harmonic component and power factor of the power grid are taken as two objective functions to model the power grid. The improved particle swarm optimization (PSO) genetic algorithm is used to establish the harmonic suppression and reactive power compensation model. To improve the design efficiency, aiming at the complexity of the algorithm and the field measurement data, the reactive power compensation device is quickly solved on the Hadoop cloud computing platform to achieve the global optimal compensation effect, to improve the convergence speed and global search ability of the particle swarm optimization algorithm. Thus, based on ensuring the power factor, the harmonic component is restrained and the safety and reliability of power grid operation are improved.

Shunt Active Filter Based on 7-Level Cascaded Multilevel Inverter for Harmonic and Reactive Power Compensation

This paper proposes a simple fundamental active current extraction scheme for a 1-phase 7-level cascaded multilevel inverter. The proposed algorithm extracts the fundamental active component of the load current, irrespective of the change in supply frequency. Moreover, a band pass filter (BPF) based phase locked loop (PLL) is proposed for the generation of the unit vector template (UVT). This ensures the effective operation of the SAF, even under a non-sinusoidal supply voltage. The proposed algorithm provides an instantaneous value of the fundamental active component of the load current, which when drawn from the supply ensures that the source current is sinusoidal and that the unity power factor (UPF) is maintained at the supply end. The usage of two cascaded H-bridges powered by two dc sources of different magnitude are put into use for the realization of a 1-phase 7-level cascaded inverter. The functioning of the 1-phase SAF with a fundamental current extractor scheme is examined for steady-state and dynamic operation under non-distorted and distorted supply voltages.

Reactive power and harmonic compensation: A case study for the coal-mining industry

This study reports on a case study in Grootegeluk Mine: Exxaro Coal, Lephalale, South Africa, in terms of power factor correction (PFC), load flow, harmonic frequency scans and harmonic voltage distortion analyses. The DIgSilent PowerFactory software was used for network simulations. Harmonic and reactive power compensation techniques were compared in terms of filter type evolution and technology advancement, with the use of simple trade-off criteria such as cost-effectiveness versus performance. It was found that both passive and hybrid filters were more favourable and could effectively compensate all voltage and current harmonics and reactive power for large nonlinear loads. The installation of switched PFC filter banks tuned at the fifth harmonic order accommodates future network growth and this solution can be rolled out to any mining industry as a benchmark to lower energy cost and maximise savings achievable on the electricity bill.&#x0D;

Multifunctional Hybrid Structure of SVC and Capacitive Grid-Connected Inverter (SVC//CGCI) for Active Power Injection and Nonactive Power Compensation

In this paper, the structure, coordinate control method, and parameter design of a hybrid system are proposed for active power injection and nonactive power (reactive, harmonic, and unbalance power) compensation. The proposed hybrid system consists of a static var compensator (SVC) in parallel with a capacitive-coupling grid-connected inverter (CGCI) (SVC//CGCI). In SVC//CGCI, the SVC part is used to dynamic compensate the reactive power and unbalance power, while the low rating CGCI part is used to inject active power, provide harmonic power and a fixed amount of capacitive reactive power. Compared with conventional inductive-coupling grid-connected inverter (IGCI), the CGCI can provide active, reactive and harmonic power with low rating of active inverter part. The cost of the SVC part is much lower than that of active inverter part, thus the reduction of inverter rating can lead to a decrease in the total cost of the SVC//CGCI. Therefore, the SVC//CGCI can be a cost effective solution for active power injection and nonactive power compensation. Finally, simulation and experimental results are provided to show the advantages and validity of the proposed SVC//CGCI in compared with the conventional IGCI and SVC//IGCI.

Design and implementation of a three-level active power filter for harmonic and reactive power compensation

This paper presents a unified design and implementation of active power filters (APF) for medium-voltage high-power applications. A fast and accurate harmonic extraction technique based on the time transformation algorithm (TTA) is developed. A novel approach is used to derive the mathematical model describing the relation between the output current and the control signal of the NPC inverter for active power filter. Accordingly, the current controller and voltage controller are designed using the derived model. The neutral-point voltage is maintained near zero using a feed-forward controller. The designed three-level APF is feasible to implement, comparatively cheaper and reduces the filter size. From both the simulation and experimental results, it is found that the developed system provides excellent performance in regulating voltage and reducing harmonics significantly, from 26.3% to 4.0%.

Experimental Validation of Impedance Source Network Based Active Power Filter for Interconnection of PV System into Grid

This paper proposes a Solar Photovoltaic (SPV) interfaced Impedance Source Inverter (ZSI) based shunt Active Power Filter (APF) for compensation of power quality events such as current harmonics, voltage interruption and reactive power burden. The instantaneous reactive power theories with Fuzzy Logic Controller (FLC) based DC link voltage regulator is used to estimate the reference current signal and control the operation of the SPV interfaced shunt APF. Maximum Power Point Tracking (MPPT) algorithm is also employed to obtain the optimum maximum power point. The response of the SPV interfaced ZSI-shunt APF for mitigation of current harmonic distortions and reactive power compensation are investigated and compared with SPV interfaced Voltage Source Inverter (VSI) based shunt APF. The proposed SPV interfaced shunt APF employed with the FLC-based instantaneous reactive power theory control algorithm offers long lasting compensation against current-based distortions and reactive power requirements. The performance of the SPV interfaced ZSI based shunt APF has been verified by the simulation and experimental study. These results confirm the practicability of the proposed system in various load conditions with effective harmonic mitigation capability.

Alternative Breed of Three-Phase Four-Wire Shunt Compensators Based on the Cascaded Transformer With Single DC Link

This paper discusses a variety of four-wire (4W) multilevel shunt compensators to deal with either harmonic or reactive power compensation. The converter configurations are generalized for K-stages and the main benefits of the proposed topologies lie on multilevel waveforms generation, single dc-link unit, and modular characteristic. The configurations are based on cascaded transformers along with three-phase-bridge converters. These converters are directly connected to the transformer primary side. A suitable pulse-width modulation strategy combined with an appropriate transformer turns ratio guarantees the desired multilevel output waveforms. The modularity feature provides simple maintenance and makes the proposed shunt active power filters an attractive solution in comparison with conventional configurations. The configuration model and overall control are addressed as well. Simulation and experimental results are presented for theoretical validation.