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

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.

Author(s):  
Allie E. Auld ◽  
Jack Brouwer ◽  
Scott Samuelsen ◽  
Keyue M. Smedley

The challenges associated with incorporating a large amount of distributed generation (DG), including fuel cells, into a radial distribution feeder are examined using a Matlab/Simulink™ model. Two generic distribution feeder models are used to investigate possible scenarios where voltage problems may occur. Modern inverter topologies make ancillary features, such as on-demand reactive power generation/consumption economical to include, which expands the design space across which DG can function in the distribution system. The simulation platform enables testing of the following local control goals: DG connected with unity power factor, DG and load connected with unity power factor, DG connected with local voltage regulation (LVR), and DG connected with real power curtailment. Both the LVR and curtailment strategies can regulate the voltage of the simplest circuit case, but the circuit utilizing a substation with load drop compensation has no universal solution. Even DG with a penetration level around 10% of rated circuit power can cause overvoltage problems with load drop compensation. This implies that some degree of communication will be needed to reliably install a large amount of DG on a distribution circuit.


2013 ◽  
Vol 336-338 ◽  
pp. 450-453
Author(s):  
Jian Ying Li ◽  
Wei Dong Yang ◽  
Ni Na Ma

In view of the fact that active power and reactive power have coupling relation, a novel vector decoupling control strategy is presented for three-phase voltage source PWM rectifier. In the paper, the power control mathematical mode of the PWM rectifier is deduced based on the mathematical model of rectifier in synchronous d-q rotating coordinates, and a new voltage feed forward decoupling compensation control strategy is proposed. The simulation results show that the voltage and current of the three-phase PWM rectifier have better respond preference, the current aberrance is smaller and the voltage is steady under the control strategy. The PWM rectifier can implement PWM commute with unity power factor, but also feed back the energy to AC side with unity power factor.


In this paper, the effects of the grid-tie photovoltaic plant (PV) are analyzed on the power factor and the voltage harmonic distortion in the power quality aspect of the distribution network. The conditions for the total harmonic distortion (THD) in the power grid related to the photovoltaic power station connected to the user side are also summarized. Based on MATLAB/SIMSCAPE software, one string of the photovoltaic system at the Jordan University of Science and Technology (JUST) was simulated and hence, compared its results with the real results of the system. Measurement and simulation results illustrate that the voltage harmonic distortions to the power grid do not exceed the recommended levels, but the photovoltaic system needs to have a capacitor bank to get a unity power factor.


Author(s):  
R. Arulmurugan

This paper proposed a Transformer less Hybrid SEries Active Filter (THSeAF) that upgrade the power quality in single-stage frameworks with steady renewable Photo Voltaic (PV) supply. It strengthens basic loads and carrying on as high-consonant impedance that does not below the critical loads, it cleans power system and guarantees the utilization of unity power factor. Here we manages energy management and power quality issues identified with electric transportation and concentrate on enhancing the electric vehicle load connected to grid. This depends on the Power Factor Correction (PFC) change with harmonic modulation technique that will give advancement of power factor in PFC operation. The control technique was intended to anticipation of current harmonic distortions with the nonlinear loads to control the flow of utility with no standard massive and expensive transformer. Power factor alongside AC side will likewise kept up to some esteem and furthermore dispense with the voltage distortions at the Common coupling point. Here we protecting sensitive loads from voltage twists, swells and sags as for control framework, without the arrangement transformer it is worthwhile for a modern usage. This paper was done with 2-kVA control showing the adequacy of the current topology.


2014 ◽  
Vol 3 (3) ◽  
pp. 378
Author(s):  
Narin Watanakul

This paper proposes two stages of controller. First stage, direct power control (P-Q control) applied single-phase structure of multilevel modular converter (MMC) , multilevel cascaded H-Bridge inverter with 9-level SPWM injection to medium voltage (24kV) based on wind turbine generator (PMSG)rated capacity 25kVA. Second stage, three-phase PFC rectifier with phase-modular Y-rectifier, boosttype. The separate dc sources (DC-links) average voltage at 178V (Vdc1-Vdc12). This study is concerned with the application, operating, principle, and design example. The unity power factor operation of PMSG is realized by controlling of phase-modular Y-Rectifier system, and the current waveform distortion results increase of the lower harmonics distortion. The P-Q controller can make it possible of the grid line current phase by providing the direct instantaneous power control in the steady state under the active power and reactive power command. The data collected by PSIM and MATLAB simulation are used in comparison with the experimental tester of results. This provides guideline to further analyze and improvement energy efficiency and power quality in electrical system pertinent to wind turbine generator (PMSG). Keywords: Wind Turbine Generator, Permanent Magnet Synchronous Generator (PMSG), Phase-Modular Y-Rectifier, Cascaded H-Bridges, Modular Multilevel Converter (MMC), Power Quality, Unity Power Factor, Harmonics.


Author(s):  
DEVENDRA LAXMAN RAOKHANDE ◽  
DADGONDA PATIL

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.


Author(s):  
Faheem Ali ◽  
Muhammad Naeem Arbab ◽  
Gulzar Ahmed ◽  
Majid Ashraf ◽  
Muhammad Sarim

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.


Author(s):  
Faheem Ali ◽  
Muhammad Naeem Arbab ◽  
Gulzar Ahmed ◽  
Majid Ashraf ◽  
Muhammad Sarim

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.


Author(s):  
Gunjan Varshney ◽  
Durg S. Chauhan ◽  
Madhukar P. Dave ◽  
Nitin

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.


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