Reactive Power Components Research Articles

Pattern Control Algorithm based DSTATCOM for Power Quality Applications

Modern power systems are continuously being expanded and upgraded to cater the need of ever growing power demand. But, in recent years, energy planners have faced financial and environmental difficulties in expanding the power generation and transmission systems. These difficulties included limited available energy resources, time and capital required and also the land use restrictions etc. These situations have forced planning engineers to look for new techniques for improving the performance of existing power system. This paper aims to implement the Voltage source converter based D-STATCOM to improve the performance of power systems. The proposed work enhances the power quality problems using pattern controller for three-phase distribution static compensator (DSTATCOM) under different load condition. The proposed DSTATCOM is used for harmonics elimination, load balancing and reactive power compensation with pattern control algorithm in distribution system. The pattern control algorithm is used for removal of harmonic values of active and reactive power components. The steady state error and improved speed response are improved using pattern controller. The detailed modeling and simulations results of different control strategies of DSTATCOM were implemented along with the necessary equations in the MATLAB simulink using the simpower systems toolboxes. Simulation results are discussed and various case studies applied depending on the various loads like linear and nonlinear load on the DSTATCOM simulink models and the simulation results are studied.

Damping interarea oscillations in power systems using finite time terminal sliding mode control of the unified power flow controller

This paper presents a new nonlinear controller for unified power flow controller (UPFC) based on the Lyapunov's finite time terminal sliding mode concept. Further instead of controlling the direct and quadrature-axis currents of the series voltage source converter (VSC), the instantaneous real-and reactive power components are used as control variables. This mode of control dispenses the unmodelled dynamics of the VSC phase-locked loop system and produces a robust control for the active-reactive power, and dc voltage excursions. Computer simulation results are obtained for a variety of operating conditions for 3-machine 6-bus power system using the finite time terminal sliding mode control and the results are compared with a standard input-output feedback linearisation approach to validate the superiority of the proposed controller.

화학 플랜트에서의 비상발전기 용량선정 방안(PG3)에 관한 연구

PG and RG methods are widely known method for calculating the capacity of the emergency generator in construction electrical installation. PG and RG methods are mainly used as a saving a life, fire protection, fire fighting in construction. Because no long distance between the emergency generator and electric motor feeder, the relatively small motor power in construction electrical installation, the capacity of generator in PG and RG methods are little problem of voltage and reactive power of generator. However in many cases the application of the PG and RG method is difficult in the Chemical Plant because it is long distance between the generator and the motor Feeder and motor capacity is very large. Motor starting power factor is about 0.2 lagging power factor and motor starting current is about 6times during motor staring. Also Most of the staring current component is a reactive power component. therefore, it is many cases that lack of reactive power and excess of allowable voltage drop limit and After selection of emergency diesel generator, problems happen during motor starting. Therefore, to be selection of effective emergency generator, active generator power, reactive power and the required reactive power during large motor starting should be considered in chemical plant. It is also required of the verification process through simulation because hand calculation is very difficult considering study cases.

Power Quality Improvement in Isolated Distributed Power Generating System Using DSTATCOM

This paper presents the control of a synchronous reluctance generator (SyRG) driven by a biogas/biomass diesel engine as a prime mover in a distributed power generating system. This generator is used as a source to feed linear and nonlinear loads. A three-leg voltage source converter (VSC)-based distribution static compensator (DSTATCOM) is implemented using an adaptive neural network-based control algorithm for harmonic suppression, load balancing, and voltage regulation in a three-phase SyRG system with a battery energy storage system. This control algorithm is used for extraction of active and reactive power components of distorted load currents. These components of load currents are used for estimation of reference source currents to generate the gating pulses of VSC used as DSTATCOM. The performance of DSTATCOM is observed satisfactory for this type of power generating system under balanced and unbalanced loads.

Finite-time sliding mode power control of grid-connected three-phase photovoltaic array

A new direct power control formulation for the voltage source converter (VSC) in a grid-connected photovoltaic (PV) array is discussed in this paper. Instead of controlling the direct- and quadrature-axis currents of the VSC through the use of a phase-locked loop system (PLL), the instantaneous real- and reactive-power components are used as control variables. This approach, therefore, does not take into account the unmodelled dynamics of the PLL resulting in a robust control of the active, reactive powers while maintaining the photovoltaic (PV) array voltage at a constant value. Further, the stability of the grid-connected PV array is enhanced by designing a Lyapunov’s function-based finite-time non-linear reactive power and dc-link voltage controller, which essentially uses the terminal sliding mode approach. To prove the robustness of the proposed approach, several system disturbances like changes in solar insolation and active and reactive power references, islanding conditions, converter parametric changes, and faults on the converter and inverter buses are considered. In all these cases, the new controller is found to enhance overall system stability in comparison to the inferior performance by the proportional-integral controller

Variable Forgetting Factor Recursive Least Square Control Algorithm for DSTATCOM

This paper proposes an implementation of distribution static compensator (DSTATCOM) for the three-phase distribution system. The functions of DSTATCOM are harmonics elimination, compensation of reactive power, and load balancing in power factor correction and voltage regulation modes. A variable forgetting factor recursive least square (VFFRLS)-based control algorithm is proposed for effective operation of DSTATCOM to estimate weighted values of active and reactive power components of load current. The proposed control algorithm is fast in convergence and has quick response. A prototype of DSTATCOM is developed in the laboratory using a digital signal processor (dSPACE 1104) and voltage-source converter and tested for various operating conditions under nonlinear load. The performance of DSTATCOM is found satisfactory in mitigating various power-quality problems with the VFFRLS-based control algorithm.

Application of Power Matrix Technique for Controlling DFIG Wind Turbine System

This paper proposes a new adaptive control technique for doubly fed induction generator wind energy system called Power Transfer Matrix. For this matrix the state variables considered as instantaneous real and reactive power components. It is shown that using the power transfer matrix model improves the robustness of controllers as the power waveforms are independent of a dqo frame of reference. In order to protect the power converters of DFIG during fault a power/current scheme is presented. The performance of the proposed grid connected DFIG wind energy system is investigated in dynamic modelling. These systems are experimented in Matlab/Simulink and verify the results in time domain analysis.

The efficiency of introducing onboard reactive power compensators on electric rolling stock of alternating current

Questions of energy efficiency of ac electric rolling stock are considered in this paper. Data on the very low power factor in the cargo electric ac locomotives that are in operation on the railways of the Russian Federation on the unmanaged valves, as well as with the reversible converters on thyristors, are provided. The results of operational tests on the railways, which found that almost every kilowatt-hour of active power is accompanied by energy consumption of 1 kVAr h reactive energy; i.e., the value of the power factor varies by approximately 0.7, are given. For example, a simplified power supply scheme of an electric locomotive from a traction substation with identified components of full power is given, as are expressions that allow the influence to be determined of active and reactive power components on energy losses in the power transmission lines. Special attention is paid to the determination of voltage losses in the contact network, which is of particular relevance when driving heavy trains. The results of calculation of power losses in the traction power supply system and the loss of voltage in the contact network, depending on the power factor at different powers of electric locomotives for the average electric operating mode, are given. A vector diagram that shows the prevailing influence of the reactive current component of an electric locomotive on the loss of voltage in the contact network is provided. On the basis of the analysis, it is found that positioning devices of reactive power compensation (RPC) directly on an electric rolling stock is the most effective way to improve the power factor on the electric current collector of an electric locomotive and reduce the power consumption for the traction of trains. The results of tests and trial operation of electric locomotives equipped with a onboard adjustable reactive power compensator are given.

Reviews on MATLAB DSTATCOM Simulation Models in Mitigating Power Quality Problems

This paper reviews the performance of detailed and average model for distribution static compensator (DSTATCOM) in order to remove voltage flicker, regulate the voltage at point of common coupling (PCC), power factor correction and harmonics elimination. In these models, d-q theory is used to extract fundamental active and reactive power components of the load currents which will be required to estimate the reference source currents. Both models are evaluated and compared in MATLAB/Simulink based simulation platform.

Power Factor Improvement Using a Three Phase Shunt Active Power Filter

The increasing growth in the use of electronic equipment in recent years has resulted in a greater need to ensure that the line current harmonic content of any equipment connected to the ac mains is limited to meet regulatory standards. Shunt Active Power Filters (SAPF) are used to compensate both harmonic and reactive current component for the power supplies. It also improves the power quality and power factor on power utility. In this paper, Application of Direct Testing and Calculating Method (DTCM) in Shunt Active filters is proposed to estimate reference current signal, and apply hysteresis control to generate gate pulses. The results of simulation study of control scheme presented in this paper is found quite satisfactory for eliminate harmonics and reactive power components from utility, successful in meeting the IEEE 519 recommended harmonic standard limits.

Control technique for enhancing the stable operation of distributed generation units within a microgrid

This paper describes a control technique for enhancing the stable operation of distributed generation (DG) units based on renewable energy sources, during islanding and grid-connected modes. The Passivity-based control technique is considered to analyze the dynamic and steady-state behaviors of DG units during integration and power sharing with loads and/or power grid, which is an appropriate tool to analyze and define a stable operating condition for DG units in microgrid technology. The compensation of instantaneous variations in the reference current components of DG units in ac-side, and dc-link voltage variations in dc-side of interfaced converters, are considered properly in the control loop of DG units, which is the main contribution and novelty of this control technique over other control strategies. By using the proposed control technique, DG units can provide the continuous injection of active power from DG sources to the local loads and/or utility grid. Moreover, by setting appropriate reference current components in the control loop of DG units, reactive power and harmonic current components of loads can be supplied during the islanding and grid-connected modes with a fast dynamic response. Simulation results confirm the performance of the control scheme within the microgrid during dynamic and steady-state operating conditions.

A Multifunction Control Strategy for the Stable Operation of DG Units in Smart Grids

This paper describes the development of a multifunction control strategy for the stable operation of distributed generation (DG) units during the integration with the power grid. The proposed control model is based on direct Lyapunov control (DLC) theory and provides a stable region for the proper operation of DG units during the integration with the power grid. The compensation of instantaneous variations in the reference current components in ac-side and dc-voltage variations in the dc-side of the interfacing system are adequately considered in this control plan, which is the main contribution and novelty of this paper in comparison with previous control strategies. Utilization of the DLC technique in DG technology can confirm the continuous injection of maximum active power in fundamental frequency from the DG source to the power grid, compensating all the reactive power and harmonic current components of grid-connected loads through the integration of DG link into the grid. Application of this concept in smart grids system can guarantee to reduce the stress on the utility grid during the peak of energy demand. Simulation and experimental test results are presented to demonstrate the proficiency and performance of the proposed DLC technique in DG technology.

Implementation of Kernel Incremental Metalearning Algorithm in Distribution Static Compensator

This paper presents implementation of distribution static compensator (DSTATCOM) using kernel incremental metalearning algorithm (KIMEL) control algorithm. It demonstrates the functions of DSTATCOM such as reactive power compensation, harmonics elimination, and load balancing under linear and nonlinear loads with its self-supporting dc-bus voltage. The proposed control algorithm based on KIMEL is applied for extraction of fundamental active and reactive power components of load currents that are required for estimation of reference supply currents. These reference supply currents are used for gating pulses generation using indirect current control principle. A DSTATCOM with features of self-supporting dc bus (capacitor) is developed using DSP (dSPACE-1104), and the response of proposed control algorithm is studied under various operating conditions and found satisfactory.

Improving Electric Power Quality within the Power Supply System of Wide-strip Hot-rolling Mill Stand

The paper proposes studies of electric power quality indexes for 10 kV network supplying electric drives of the wide-strip hot-rolling mill stand equipped with thyristor electric drives. It provides the power supply diagram of the plate rolling shop. Information on the methods of experimental studies of the current and voltage spectral distribution with the use of a standard measuring device and software is provided. The paper shows the nature of higher-order harmonics content for units of the 10kV distribution substation. It considers the method and system for reactive power control in the load center that ensures a step power change of the reactive-power compensator batteries and the following smooth fine adjustment by automatic control of synchronous motor excitation current. According to the algorithm proposed condenser batteries shall be operated in the basic mode and compensate a semi-constant component of reactive power.

IJIREEICE - Electrical, Electronics, Instrumentation and Control

Transmission lines are used to transmit electric power for large distances in electrical power systems. The rapid growth of electrical power systems over the past few decades has resulted in a massive increase of the quantity of lines operative and their total length. These lines are exposed to faults as a result of lightning, short circuits, faulty equipments &human errors. This paper presents a novel approach for fault classification and faulted phase selection for Transmission lines that is dispensed with sequential reactive power components. The proposed technique has been taking a look at about two cases and every case has eighteen test cases from each end. This technique identifies single line to ground fault, double line to ground fault & double line faults for given test case systems and this is implemented using Mat Lab software package.

Spheroidal wave solutions for sound radiation problems in the near-field of planar structures

Current research in active noise control and in the reconstruction of vibrating sources often requires knowledge of the independent source–field components that best represent the complex acoustical transfer paths observed between a radiating structure and a given control or observation domain. In this paper, closed-form solutions are provided for the singular value expansion of the radiation operator that maps the boundary velocity of a baffled rectangular structure onto the acoustic pressure observed in the half-space domain over a hemi-spheroidal surface located at an arbitrary separation distance from the radiator, including in the near-field zone. Independent contributions of the evanescent and propagating wave components to the complex power are examined for a baffled beam when varying the frequency and the source–field distance parameter. It is shown that the reactive-to-active power ratio induced by each singular mode follows an inverse power law that scales on the product between the reduced frequency and the source–field distance parameter. A transitional region is defined in the space-frequency domain within which the reactive power components are preponderant and should be accounted for when controlling or imaging the near-field zone of a planar radiator. The optimality of the singular source modes is found to be of interest to actively reduce the active and reactive power components in the near-field zone of a radiator with a limited number of independent control channels.

Direct Lyapunov Control Technique for the Stable Operation of Multilevel Converter-Based Distributed Generation in Power Grid

This paper deals with a control strategy of multilevel converter topologies for integration of distributed generation (DG) resources into the power grid. The proposed control plan is based on the direct Lyapunov control (DLC) technique, which is an appropriate tool for the analysis and definition of a stable operating condition for DG link in the power grid. The compensation of instantaneous variations in the reference current components in ac side and dc voltage variations of cascaded capacitors in dc side of the interfacing system is considered properly, which is the main contribution and novelty of this paper in comparison with other control methods. By utilization of the proposed control technique, DG can provide continuous injection of active power in fundamental frequency from the dispersed energy sources to the grid. In addition, reactive power and harmonic current components of nonlinear loads can be provided with fast dynamic response, by setting a multiobjective reference current component in the current loop of DLC-based model. Therefore, achieving sinusoidal grid currents in phase with load voltages are possible, while the required power from the load side is more than the maximum capacity of interfaced multilevel converter. Simulation results confirm the effectiveness of the proposed control strategy in DG technology during dynamic and steady-state operating conditions.

Learning-Based Anti-Hebbian Algorithm for Control of Distribution Static Compensator

This paper deals with an implementation of a distribution static compensator (DSTATCOM) using a learning-based anti-Hebbian control algorithm for compensation of linear/nonlinear loads. The proposed control algorithm is used for extraction of fundamental active and reactive power components of load currents for estimating reference supply currents. This control algorithm is implemented on a developed DSTATCOM using a digital signal processor for reactive power compensation, harmonics elimination, and load balancing. Simulation and test results demonstrate satisfactory performance of the proposed control algorithm for the control of DSTATCOM under varying loads.

Implementation of Adaptive Filter in Distribution Static Compensator

This paper presents an implementation of an adaptive filter in a three-phase distribution static compensator (DSTATCOM) used for compensation of linear/nonlinear loads in a three-phase distorted voltage ac mains. The proposed filter, which is based on adaptive synchronous extraction, is used for extraction of fundamental active- and reactive-power components of load currents in estimating the reference supply currents. This control algorithm is implemented on a developed DSTATCOM for reactive-power compensation, harmonics elimination, load balancing, and voltage regulation under linear and nonlinear loads. The performance of DSTATCOM is observed satisfactory under unbalanced time-varying loads.

Simple peak detection control algorithm of distribution static compensator for power quality improvement

This study deals with the control of a three-phase, four-wire distribution static compensator (DSTATCOM) based on the peak detection of load currents for power quality improvement under linear/non-linear loads. This control algorithm is simple and easy in real time implementation. In this control algorithm, an extraction of active and reactive power components of load currents is based on a low-pass filter and the voltage unit vector in time domain. It is based on the mathematical formulations for fast and accurate estimation of reference supply currents. A four-wire DSTATCOM is modelled and implemented for the compensation of linear and non-linear loads using a digital signal processor. Performance of DSTATCOM is found quite satisfactory under balanced and unbalanced loads in three-phase, four-wire distribution system.