A NOVEL CONTROL STRATEGY FOR SERIES-SHUNT POWER QUALITY COMPENSATOR

2015 ◽  
pp. 148-153
Author(s):  
DEVENDRA LAXMAN RAOKHANDE ◽  
DADGONDA PATIL
Keyword(s):  
Power Quality ◽  
High Voltage ◽  
Power Factor ◽  
Control Strategy ◽  
Reactive Power ◽  
Voltage Regulation ◽  
Current Harmonics ◽  
Synchronous Reference Frame ◽  
Uninterruptible Power ◽  
Traction System

Advancement and extensive use of power electronic devices such as, fast switching uncontrolled/controlled convertors, invertors and cyclo-converters, high voltage power convertors used in HVDC, high voltage drives in traction system, arc furnaces, modern single phase electronic equipments like Compact Fluorescent Lamps (CFLs), Uninterruptible Power Supply (UPS), Personal Computers (PCs), printers, battery chargers, fax machines, photocopiers etc. creates power quality problems, the measure of it was voltage and current harmonics, poor power factor, imbalance, reactive power compensation, voltage regulation etc. Ideally power system network must be electrically clean, harmonics free, balanced, sinusoidal with unity power factor and regulated. This work deals with the performance of Series-Shunt Power Quality Compensator (SSPQC) under distorted source voltages and load currents. In this work a novel control strategy of Synchronous Reference Frame (SRF) used to extract the fundamental reference voltage component and the ICC based technique used to predict source current which simplifies the computation and amplifies the system performance.

scholarly journals Voltage Rise Regulation with a Grid Connected Solar Photovoltaic System

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7510
Author(s):  
Akinyemi Ayodeji Stephen ◽  
Kabeya Musasa ◽  
Innocent Ewean Davidson
Keyword(s):  
Power Quality ◽  
Power Factor ◽  
Reactive Power ◽  
Voltage Regulation ◽  
Photovoltaic System ◽  
Voltage Amplitude ◽  
Phase Voltage ◽  
Unity Power Factor ◽  
Voltage Rise ◽  
Grid Current

Renewable Distributed Generation (RDG), when connected to a Distribution Network (DN), suffers from power quality issues because of the distorted currents drawn from the loads connected to the network over generation of active power injection at the Point of Common Coupling (PCC). This research paper presents the voltage rise regulation strategy at the PCC to enhance power quality and continuous operation of RDG, such as Photovoltaic Arrays (PVAs) connected to a DN. If the PCC voltage is not regulated, the penetration levels of the renewable energy integration to a DN will be limited or may be ultimately disconnected in the case of a voltage rise issue. The network is maintained in both unity power factor and voltage regulation mode, depending on the condition of the voltage fluctuation occurrences at the PCC. The research investigation shows that variation in the consumer’s loads (reduction) causes an increase in the power generated from the PVA, resulting in an increase in the grid current amplitude, reduction in the voltage of the feeder impedance and an increase in the phase voltage amplitude at the PCC. When the system is undergoing unity power factor mode, PCC voltage amplitude tends to rises with the loads. Its phase voltage amplitude rises above an acceptable range with no-loads which are not in agreement, as specified in the IEEE-1547 and Southern Africa grid code prerequisite. Incremental Conduction with Integral Regulator bases (IC + PI) are employed to access and regulate PVA generation, while the unwanted grid current distortions are attenuated from the network using an in-loop second order integral filtering circuit algorithm. Hence, the voltage rise at the PCC is mitigated through the generation of positive reactive power to the grid from the Distribution Static Compensator (DSTATCOM), thereby regulating the phase voltage. The simulation study is carried out in a MATLAB/Simulink environment for PVA performance.

scholarly journals Current-Limiting Soft Starting Method for a High-Voltage and High-Power Motor

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3068
Author(s):  
Yifei Wang ◽  
Kaiyang Yin ◽  
Youxin Yuan ◽  
Jing Chen
Keyword(s):  
High Voltage ◽  
Power Factor ◽  
High Power ◽  
Reactive Power ◽  
Characteristic Curve ◽  
Voltage Regulation ◽  
Reactive Power Compensation ◽  
Starting Current ◽  
Reactive Compensation ◽  
Current Limiting

Focusing on the starting problems of a high-voltage and high-power motor, such as large starting current, low power factor, waste of resources, and lack of harmonic control, this paper proposes a current-limiting soft starting method for a high-voltage and high-power motor. The method integrates functions like autotransformer voltage reduction–current limiting starting, magnetron voltage regulation–current limiting starting, and reactive power compensation during starting, and then the power filtering subsystem is turned on to filter out harmonics in power system as the starting process terminates. According to the current-limiting starting characteristic curve, the topological structure of the integrated device is established and then the functional logic switching strategy is put forward. Afterwards, the mechanisms of current-limiting starting, reactive compensation and dynamic harmonic filtering are analyzed, and the simulation and experimental evaluation are completed. In particular, the direct starting and the current-limiting are performed by developing a simulation system. In addition, a 10 kV/19,000 kW fan-loaded motor of a steel plant is chosen as the subject to verify the performance of the current-limiting soft starting method. As shown by the experimental results, the motor’s starting current is about 2 times that of its rated current, the power factor is raised to over 0.9 after the reactive power compensation, and the harmonic filter can effectively eliminate current harmonics and reduce the total harmonic distortion (THD) of supply currents.

scholarly journals Model Predictive Current Control with Asymmetric Stacked Multilevel Inverter and LCL-Filter Based STATCOM

2021 ◽  
Vol 3 (2) ◽  
pp. 19-30
Author(s):  
Mostafa Q. Kasim ◽  
Raaed Faleh Hassan
Keyword(s):  
Power Factor ◽  
Control Strategy ◽  
Reactive Power ◽  
Current Control ◽  
Multilevel Inverter ◽  
Harmonic Current ◽  
Source Power ◽  
Current Harmonics ◽  
Source Current ◽  
Sampling Instant

The work presented in this paper deals with a proposal of a new topology of a multilevel inverter to act as a Static synchronous Compensator (STATCOM). The proposed inverter is the five-level Asymmetric Stacked Multi-Level Inverter (ASMLI). One of the essential features of this inverter that distinguishes it from the conventional types is that it achieves the required voltage levels with fewer switching devices, leading to simplifying the control process. Moreover, the work includes using a Finite Control Set Model Predictive Current Control (FCS-MPCC) to control the proposed structure. The FCS-MPCC control strategy performs the finite optimization process at the current sampling instant to provide the optimum switching states to the inverter at the next sampling instant. Therefore, this control strategy allows injecting harmonic current and reactive power compensation to reduce source current distortion and improve the voltage profile and power factor. The optimization mechanism reduces the cost function, which is a function of measuring the network current's deviation from the reference value and how the capacitor voltage deviates from the required values. LCL-filter was used to connect this setup to the grid, and its resonance was actively damped using the multivariable capabilities of the FCS-MPCC. The proposed control framework was simulated using MATLAB/Simulink 9.1 environment and tested in a distorted and healthy network compared to a conventional two-level converter with RL-filter. The STATCOM was used to inject reactive power to raise the source power factor to unity and reduce source current harmonics by injecting harmonic current. The proposed prototype could absorb 70% of source current harmonics, which is nearly 25% better than a conventional inverter, inject an appropriate amount of reactive power, and raise the source power factor to unity in two case scenarios. The performance achieved was promising at steady-state operation and speedy response during transients with balanced capacitors voltages.

scholarly journals An SVC controller for Power Quality Improvement of a Heavily Loaded Grid

2020 ◽  
Vol 39 (2) ◽  
pp. 247-256
Author(s):  
Faheem Ali ◽  
Muhammad Naeem Arbab ◽  
Gulzar Ahmed ◽  
Majid Ashraf ◽  
Muhammad Sarim
Keyword(s):  
Quality Improvement ◽  
Power Quality ◽  
Power Factor ◽  
Distribution System ◽  
Reactive Power ◽  
Cooling System ◽  
Voltage Regulation ◽  
Voltage Regulators ◽  
Air Cooling ◽  
Power Quality Improvement

Pakistan is faced with energy crises from the last two decades. Generation cannot balance the load demands of the electricity consumers. Power delivery systems are generally old-fashioned and overloaded. They are unable to provide consistent and uninterrupted supply to commercial, industrial, and domestic loads. Generally speaking, the Power Systems consist of loads that are inductive and resistive in nature. Heavy machinery, induction motors, and arc furnaces are heavily inductive in nature. Inductive loads when operated in a weak power system results in lagging VARs (Volt Ampere Reactive) and poor voltage regulation, which must be balanced by the same number of leading VARs in order to ensure unity power factor and thus helps in improving the voltage profile. At times the reactive VARs injected may not be sufficient to balance the VARs requires by the system, but still the power factor is improved up to some extent. In hot and humid climatic conditions, air-cooling system and chillers greatly burdens the grids. Such loads require excessive reactive VARs, and if not offered with ample reactive power, causes severe voltage drops in distribution system. To manage low voltages and power-factor, household users use automatic voltage regulators while industries connect capacitor banks. Voltage regulators control output voltage within the required limits at the expense of excessive line current from transformer, which may overburden it. Moreover, with each operation of tap changer, current rises which further intensifies line losses. Static capacitors provide stable voltage but repeated variations in load demands reliable and vigorous voltage regulation. This investigation aims to come up with a power quality improvement scheme which would deliver instantaneous control of power (reactive) with SVC (Static VAR Compensator) thus overcoming the shortcomings of step-wise banks of capacitors and or voltage regulators. Simulation work is carried out in MATLAB/SIMULINK and the results are compliance with IEEE Standards for SVCs. The device can offer steady state as well as dynamic VAR compensation under changing load conditions. Result showed considerable improvement both in terms of response time and power factor. Switching time has been improved to less than 1/10th fraction of a second which in previous simulations was 0.7 seconds approximately. Initial power factor without disturbance and without compensation was recorded to be 0.6 lagging, which after compensation was improved to 0.95 lagging. Similarly, in presence of disturbance without compensation the power factor fluctuated between 0.55 and 0.9 lagging, which after compensation was improved to 0.95 lagging and above throughout the course of operation.

scholarly journals An SVC controller for Power Quality Improvement of a Heavily Loaded Grid

2020 ◽  
Vol 39 (2) ◽  
pp. 247-256
Author(s):  
Faheem Ali ◽  
Muhammad Naeem Arbab ◽  
Gulzar Ahmed ◽  
Majid Ashraf ◽  
Muhammad Sarim
Keyword(s):  
Quality Improvement ◽  
Power Quality ◽  
Power Factor ◽  
Distribution System ◽  
Reactive Power ◽  
Cooling System ◽  
Voltage Regulation ◽  
Voltage Regulators ◽  
Air Cooling ◽  
Power Quality Improvement

Pakistan is faced with energy crises from the last two decades. Generation cannot balance the load demands of the electricity consumers. Power delivery systems are generally old-fashioned and overloaded. They are unable to provide consistent and uninterrupted supply to commercial, industrial, and domestic loads. Generally speaking, the Power Systems consist of loads that are inductive and resistive in nature. Heavy machinery, induction motors, and arc furnaces are heavily inductive in nature. Inductive loads when operated in a weak power system results in lagging VARs (Volt Ampere Reactive) and poor voltage regulation, which must be balanced by the same number of leading VARs in order to ensure unity power factor and thus helps in improving the voltage profile. At times the reactive VARs injected may not be sufficient to balance the VARs requires by the system, but still the power factor is improved up to some extent. In hot and humid climatic conditions, air-cooling system and chillers greatly burdens the grids. Such loads require excessive reactive VARs, and if not offered with ample reactive power, causes severe voltage drops in distribution system. To manage low voltages and power-factor, household users use automatic voltage regulators while industries connect capacitor banks. Voltage regulators control output voltage within the required limits at the expense of excessive line current from transformer, which may overburden it. Moreover, with each operation of tap changer, current rises which further intensifies line losses. Static capacitors provide stable voltage but repeated variations in load demands reliable and vigorous voltage regulation. This investigation aims to come up with a power quality improvement scheme which would deliver instantaneous control of power (reactive) with SVC (Static VAR Compensator) thus overcoming the shortcomings of step-wise banks of capacitors and or voltage regulators. Simulation work is carried out in MATLAB/SIMULINK and the results are compliance with IEEE Standards for SVCs. The device can offer steady state as well as dynamic VAR compensation under changing load conditions. Result showed considerable improvement both in terms of response time and power factor. Switching time has been improved to less than 1/10th fraction of a second which in previous simulations was 0.7 seconds approximately. Initial power factor without disturbance and without compensation was recorded to be 0.6 lagging, which after compensation was improved to 0.95 lagging. Similarly, in presence of disturbance without compensation the power factor fluctuated between 0.55 and 0.9 lagging, which after compensation was improved to 0.95 lagging and above throughout the course of operation.

Unit Template Based Control of PV-DSTATCOM

2020 ◽  
Vol 13 (1) ◽  
pp. 36-42
Author(s):  
Gunjan Varshney ◽  
Durg S. Chauhan ◽  
Madhukar P. Dave ◽  
Nitin
Keyword(s):  
Power Quality ◽  
Power Factor ◽  
Power Distribution ◽  
Distribution System ◽  
Distribution Systems ◽  
Phase Distribution ◽  
Voltage Regulation ◽  
Photovoltaic Array ◽  
Quality Issues ◽  
Static Compensator

Background: In modern electrical power distribution systems, Power Quality has become an important concern due to the escalating use of automatic, microprocessor and microcontroller based end user applications. Methods: In this paper, power quality improvement has done using Photovoltaic based Distribution Static Compensator (PV-DSTATCOM). Complete simulation modelling and control of Photovoltaic based Distribution Static Compensator have been provided in the presented paper. In this configuration, DSTATCOM is fed by solar photovoltaic array and PV module is also helpful to maintain the DC link voltage. The switching of PV-STATCOM is controlled by Unit template based control theory. Results: The performance of PV-DSTATCOM has been evaluated for Unity Power Factor (UPF) and AC Voltage Control (ACVC) modes. Here, for studying the power quality issues three-phase distribution system is considered and results have been verified through simulation based on MATLAB software. Conclusion: Different power quality issues and their improvement are studied and presented here for harmonic reduction, DC voltage regulation and power factor correction.

scholarly journals Using Energy Storage Inverters of Prosumer Installations for Voltage Control in Low-Voltage Distribution Networks

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1121
Author(s):  
Rozmysław Mieński ◽  
Przemysław Urbanek ◽  
Irena Wasiak
Keyword(s):  
Energy Storage ◽  
Control Strategy ◽  
Reactive Power ◽  
Low Voltage ◽  
Storage System ◽  
Distribution Networks ◽  
Energy Storage System ◽  
Voltage Regulation ◽  
Active Power ◽  
Total Power

The paper includes the analysis of the operation of low-voltage prosumer installation consisting of receivers and electricity sources and equipped with a 3-phase energy storage system. The aim of the storage application is the management of active power within the installation to decrease the total power exchanged with the supplying network and thus reduce energy costs borne by the prosumer. A solution for the effective implementation of the storage system is presented. Apart from the active power management performed according to the prosumer’s needs, the storage inverter provides the ancillary service of voltage regulation in the network according to the requirements of the network operator. A control strategy involving algorithms for voltage regulation without prejudice to the prosumer’s interest is described in the paper. Reactive power is used first as a control signal and if the required voltage effect cannot be reached, then the active power in the controlled phase is additionally changed and the Energy Storage System (ESS) loading is redistributed in phases in such a way that the total active power set by the prosumer program remains unchanged. The efficiency of the control strategy was tested by means of a simulation model in the PSCAD/EMTDC program. The results of the simulations are presented.

scholarly journals Decoupled Control of Three Phase Grid Connected Solar PV System

2019 ◽  
Vol 9 (2) ◽  
pp. 4218-4222
Keyword(s):  
Solar Energy ◽  
Power Factor ◽  
Control Strategy ◽  
Reactive Power ◽  
Standard Test ◽  
Effective Control ◽  
Solar Pv ◽  
Pv System ◽  
Three Phase ◽  
Decoupled Control

A reliable grid connected Photovoltaic (PV) system require effective control schemes for efficient use of solar energy. This paper presents a three-phase grid tied PV system with decoupled real and reactive power control to achieve desired power factor with Maximum Power Point Tracking (MPPT) controller to get maximum solar energy. The synchronous reference frame (dq) control along with decoupling concept is used to control the DC-AC inverter output, while the Phase Locked Loop (PLL) synchronization technique is used to monitor and synchronize the voltage and current at the grid side. The DC-DC converter with Incremental Conductance (InC) based MPPT model is also designed in this paper due to better accuracy compared to Perturb & Observe (P&O) algorithm. The simulation is performed in MATLAB/SIMULINK and a 31.5 kW PV system is modelled to get 30 kW power with the help of MPPT at Standard Test Conditions (STC). Any power factor value between 0.85 lagging to 0.9 leading can be obtained by changingreference q current in this inverter control strategy. The simulation results show that the change of reactive powerdoes not affecttheactive power values of the system, which verifies the effectiveness of the decoupled control strategy of the inverter.

The Three-Level Sine-Wave Inverter with Power Factor Correction (PFC)

2015 ◽  
Vol 781 ◽  
pp. 402-405
Author(s):  
Napat Krachangchaeng ◽  
Sakorn Po-Ngam
Keyword(s):  
Power Factor ◽  
Output Voltage ◽  
Power Factor Correction ◽  
Sine Wave ◽  
Input Power ◽  
Small Current ◽  
Uninterruptible Power Supply ◽  
Current Harmonics ◽  
Electric Device ◽  
Uninterruptible Power

Nowadays, the uninterruptible power supply (UPS) is important in reliability for electric device. The UPS need high quality electricity. Therefore, the simulation of the three-level sine-wave inverter with power factor correction (PFC) is proposed in this paper. Moreover, the circuit’s guidelines of the active PFC controller in the active PFC and the sinusoidal output voltage are also presented. Validity of the proposed the three-level sine-wave inverter with the active PFC is confirmed by simulation. The simulation results show the very small current harmonics, the input power factor most nearly unity and constant output voltage when the suddenly step-load changed.

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