Distribution Static Synchronous Compensator Research Articles

Improvement of Power Factor and Harmonic Elimination in Distribution Line using PI with Hysteresis Current Controller

Power quality improvement is a major research area in current context. Though much work has been done by many researchers still scope is there to work on this area. In this paper an attempt is made to eliminate the harmonics as well as for the improvement of power factor. Here distribution static synchronous compensator (DSTATCOM) is used to improve power factor in distribution line & mitigate harmonics with an optional feature of voltage regulation. Further the frequency analysis of the distribution line is analyzed both before & after compensation. A relay based hysteresis current regulator is used for DSTATCOM controller in indirect current control technique. Simulation is carried out in standard MATLAB environment. Results of simulations are presented for linear & nonlinear load.

Combined control of a distribution static synchronous compensator/flywheel energy storage system for wind energy applications

The integration of wind power generation in power systems is steadily increasing around the world. This incorporation can bring problems onto the dynamics of power systems owing to the lack of controllability over the wind and the type of generation used. In this work, a distribution static synchronous compensator (DSTATCOM) coupled with a flywheel energy storage system (FESS) is used to mitigate problems introduced by wind generation in the electrical systems. A dynamic model of the DSTATCOM/FESS device is briefly presented and a technique to control the active power exchanged between the device and the power system is proposed. The control technique has two control modes. One control mode mitigates the power fluctuations of wind generators, and it is based on fuzzy logic and a special filter. The other control mode contributes to recover the frequency when significant faults arise in the system. Simulation tests on the behaviour of the device are analysed when it works in combination with wind generation in the electrical system. Results show a satisfactory performance of the proposed control techniques along with a high effectiveness to smooth the active power fluctuations of wind generation and to contribute to the recovery of the frequency.

A Transformerless D-STATCOM Based on a Multivoltage Cascade Converter Requiring No DC Sources

This paper deals with a cascaded multilevel converter which has multiple dc voltage values (multivoltage cascade converter or hybrid multilevel converter) for a 6.6-kV transformerless distribution static synchronous compensator (D-STATCOM). A control method is proposed to realize dc voltage regulation of series-connected multiple cells in the STATCOM operation, making it possible to remove dc sources from all H-bridge cells. The simplified configuration without the dc sources makes the STATCOM small and lightweight. A downscaled STATCOM model rated at 220 V and 10 kVA is built and a series of verification tests is executed. Theoretical analysis and experimental results prove the stable operating performance of the proposed method in steady states and transient states.

The LADRC Control System of Distribution Static Synchronous Compensator Based on Chaotic Sequences PFPWM

The LADRC Control System of Distribution Static Synchronous Compensator Based on Chaotic Sequences PFPWM

Multiple distribution static synchronous compensators for distribution feeder voltage support

The potential of multiple distribution static synchronous compensators (DSTATCOMs) to improve the voltage profile of radial distribution networks has been reported in the literature by few authors. However, the operation of multiple DSTATCOMs across a distribution feeder may introduce control interactions and/or voltage instability. This study proposes a control scheme that alleviates interactions among controllers and enhances proper reactive power sharing among DSTATCOMs. A generalised mathematical model is presented to analyse the interactions among any number of DSTATCOMs in the network. The criterion for controller design is developed by conducting eigenvalue analysis on this mathematical model. The proposed control scheme is tested in time domain on a sample radial distribution feeder installed with multiple DSTATCOMs and test results are presented.

Review of D-STATCOM for Stability Analysis

A Static Compensator (STATCOM) is a flexible ac transmission system (FACTS) controller, which can either absorb or deliver reactive power to a power system. Distribution STATic COMpensator (D- STATCOM) is proposed for compensation of reactive power and unbalance caused by various loads in distribution system. Distribution static compensator is based on the VSC principle. A D-STATCOM injects a current into the system to correct the voltage sag, swell and power factor. Distribution Static Synchronous Compensator (D-STATCOM) is an effective measure to maintain voltage stability and improve power quality of distribution grid. This paper deals with the modeling and control scheme of D-STATCOM. A stability analysis of D-STATCOM is obtained by bode plot approach. The theoretical analysis and design are verified by the results.

Active power control of a flywheel energy storage system for wind energy applications

The integration of wind power generation in power systems is steadily increasing around the world. This incorporation can bring problems onto the dynamics of power systems owing to the lack of controllability over the wind and the type of generation used. In this work, a distribution static synchronous compensator (DSTATCOM) coupled with a flywheel energy storage system (FESS) is used to mitigate problems introduced by wind generation in the electric system. A dynamic model of the DSTATCOM/FESS device is briefly presented and a technique to control the active power exchanged between the device and the power system is proposed. The control technique is based on fuzzy logic and a special filter. Tests of the behaviour of the device are analysed when combined with wind generation in the electric system. Results show an overall satisfactory performance of the proposed control technique along with the high effectiveness of the device used to smooth the active power fluctuations of a wind generator.

Load Compensation for Diesel Generator-Based Isolated Generation System Employing DSTATCOM

This paper presents the control of distribution static synchronous compensator (DSTATCOM) for reactive power, harmonics and unbalanced load current compensation of a diesel generator set for an isolated system. The control of DSTATCOM is achieved using least mean square-based adaptive linear element (Adaline). An Adaline is used to extract balanced positive-sequence real fundamental frequency component of the load current and a proportional-integral (PI) controller is used to maintain a constant voltage at the dc-bus of a voltage-source converter (VSC) working as a DSTATCOM. Switching of VSC is achieved by controlling source currents to follow reference currents using hysteresis-based PWM control. This scheme is simulated under MATLAB environment using Simulink and PSB block-set toolboxes for feeding linear and nonlinear loads. The modeling is performed for a three-phase, three-wire star-connected synchronous generator coupled to a diesel engine, along with the three-leg VSC working as a DSTATCOM. Results are presented to verify the effectiveness of the control of DSTATCOM for the load compensation and an optimal operation of the DG set.

Performance Evaluation of Three Different Configurations of DSTATCOM with Nonlinear Loads

This paper deals with three different configurations of Distribution Static Synchronous Compensator (DSTATCOM) for distribution system. Detailed analysis, modeling, design and control are discussed for each configuration of DSTATCOM. MATLAB based models are developed for improving power factor/voltage regulation and neutral current compensation. Results show a marked reduction in total harmonic distortion (THD) of supply current levels when applied to nonlinear loads. Dynamics of systems are reported with sudden load addition or removal and performance of system is demonstrated in detail.

Improvement Of Power Quality In Wind Energy Applications Using A Dstatcom Coupled With A Flywheel Energy Storage System

The inclusion of wind power in power systems is steadily increasing around the world. This incorporation can generate a number of problems on the dynamics of power systems. In addition, over the last few years, new power electronic devices coupled with energy storage have emerged. These new devices allow the operation of electric systems to be controlled. In this work, the use of a Distribution Static Synchronous Compensator (DSTATCOM) coupled with a Flywheel Energy Storage System (FESS) is proposed to mitigate problems, mainly in power quality, introduced by wind generation in the electric system. A dynamic model of the DSTATCOM/FESS device is presented and a multi-level control technique is proposed. The control technique has one control mode for active power and two control modes for reactive power, power factor correction, and voltage control. Tests of the behaviour of the device are analyzed when it is combined with wind generation in the electric system. The results demonstrate a satisfactory performance of the control technique proposed as well as a high effectiveness of the device, to mitigate problems introduced by wind generation.

Stabilization and control of tie-line power flow of microgrid including wind generation by distributed energy storage

High penetration of wind generation in electrical microgrids causes fluctuations of tie-line power flow and significantly affects the power system operation. This can lead to severe problems, such as system frequency oscillations, and/or violations of power lines capability. With proper control, a distribution static synchronous compensator (DSTATCOM) integrated with superconducting magnetic energy storage (SMES) is able to significantly enhance the dynamic security of the power system. This paper proposes the use of a SMES system in combination with a DSTATCOM as effective distributed energy storage (DES) for stabilization and control of the tie-line power flow of microgrids incorporating wind generation. A new detailed model of the integrated DSTATCOM-SMES device is derived and a novel three-level control scheme is designed. The dynamic performance of the proposed control schemes is fully validated using MATLAB/Simulink.

DSTATCOM with Flywheel Energy Storage System for wind energy applications: Control design and simulation

In this work, the use of a Distribution Static Synchronous Compensator (DSTATCOM) coupled with a Flywheel Energy Storage System (FESS) is proposed to mitigate problems introduced by wind generation in the electric system. A dynamic model of the DSTATCOM/FESS device is introduced and a multi-level control technique is proposed. This control technique presents one control mode for active power and two control modes for reactive power, power factor correction, and voltage control. Tests of dynamic response of the device are conducted, and performance characteristics are studied taking into consideration variations of power references. Moreover, the behaviour of the device is analyzed when combined with wind generation in the electric system. The results obtained demonstrate a good performance of the model developed and of the control technique proposed as well as a high effectiveness of the device to mitigate problems introduced by wind generation.

Experimental Validation of Nonlinear Control for a Voltage Source Converter

In this brief, we consider reactive power and DC voltage tracking control of a three-phase voltage source converter (VSC). This control problem is important in many power system applications including power factor correction for a distribution static synchronous compensator (D-STATCOM). Traditional approaches to this problem are often based on a linearized model of the VSC and proportional-integral (PI) feedback. In order to improve performance, a flatness-based tracking control for the VSC is proposed where the nonlinear model is directly compensated without a linear approximation. Flatness leads to straightforward open-loop control design. A full experimental validation is given as well as a comparison with the industry-standard decoupled vector control. Robustness of the flatness-based control is investigated and setpoint regulation for unbalanced three-phase voltage is considered.

A Minimal Harmonic Controller for a STATCOM

In this paper, a novel controller with fixed modulation index (MI) and variable dc capacitor voltage reference to minimize voltage and current harmonics is presented for a distribution static synchronous compensator (STATCOM). The STATCOM with the proposed controller consists of a three-phase voltage-sourced inverter and a dc capacitor and is used to provide reactive power compensation and regulate ac system bus voltage with minimum harmonics. A systematic design procedure based on pole-zero cancellation, root locus method, and pole assignment method has been developed to determine proper parameters for the current regulator, the dc voltage controller, and the ac voltage controller of the STATCOM. With the proposed STATCOM controller, harmonic distortions in the inverter output current and voltage can be reduced since the MI is held constant at unity in steady state. In addition, a fast adjustment in the STATCOM output reactive power is achieved to regulate the ac bus voltage through the adjustment of the dc voltage reference during the transient period. Simulation and experimental results for the steady-state operating condition and transient operating conditions for the system subjected to a reactive current reference step change, a three-phase line to neutral fault, and a step load change are presented to demonstrate the effectiveness of the proposed controller.

Modeling of D-STATCOM in distribution systems load flow

This paper presents modeling of Distribution STATCOM (D-STATCOM) in load flow calculations for the steady-state voltage compensation. An accurate model for D-STATCOM is derived to use in load flow calculations. The rating of this device as well as the direction of required reactive power injection for voltage compensation in the desired value (1 p.u.) is derived and discussed analytically and mathematically by the phasor diagram method. Furthermore, an efficient method for node and line identification used in load flow calculations is presented. The validity of the proposed model is examined by using two standard distribution systems consisting of 33 and 69 nodes, respectively. The best location of D-STATCOM for under voltage problem mitigation approach in the distribution networks is determined. The results validate the proposed model for D-STATCOM in large distribution systems.

Modelling of DSTATCOM for distribution system

This paper deals with the simulation of distribution static synchronous compensator (DSTATCOM) for improving power quality of a distribution system feeding linear as well as non-linear loads. Nowadays, there are an increasing number of non-linear loads which inject harmonics into the system. A three-phase insulated gate bipolar transistor- (IGBT-) based current controlled voltage source inverter with a DC bus capacitor known as a DSTATCOM is used for power factor correction, harmonic compensation and for providing required reactive power to the load. A model of DSTATCOM connected to a power distribution system feeding linear and non-linear loads (diode bridge rectifier with R and R-C) is developed for predicting the behaviour of system under transient conditions. Simulation is carried out in standard MATLAB environment using Simulink and power system blockset toolboxes. Control algorithm is made flexible so that it can correct supply power factor, eliminate harmonics and provide load balancing. The control algorithm utilises one closed loop PI controller for regulating the DC link voltage of DSTATCOM and second PI controller for regulating the AC voltage at point of common coupling. Results are presented for a variety of linear and non-linear balanced as well as unbalanced loads, which demonstrate power factor correction, voltage regulation, harmonic elimination and load balancing capabilities of DSTATCOM.

MATLAB-based modelling of Distribution STATCOM applied to isolated power system

This paper presents the modelling of Distribution Static Compensator (D-STATCOM) used in isolated power systems. The model of D-STATCOM is developed using Power System Block-set (PSB) and Simulink toolboxes of standard MATLAB software. Two proportional integral PI controllers are used to control DC bus voltage and AC bus voltage regulation at the point of common coupling. Results are presented for D-STATCOM used in an isolated distribution system fed from an alternator. It is observed from results that D-STATCOM is able to improve power factor, provide voltage regulation, balance the loads and reduce harmonics.

Modelagem e análise dinâmica de dispositivos DSTATCOM usando o SimPowerSystems para Matlab/Simulink

Neste trabalho apresenta-se um estudo sobre modelagem e análise dinâmica de dispositivos tipo DSTATCOM (Distribution Static Synchronous Compensator). Os objetivos são analisar o desempenho dinâmico desses equipamentos e sobretudo introduzir modelos computacionais detalhados e simplificados. Os modelos são implementados utilizando o pacote SimPowerSystems para uso com o Matlab/Simulink em razão da grande aceitação desta ferramenta computacional no ambiente acadêmico. O desenvolvimento é realizado na forma de um tutorial para facilitar o uso desses modelos por pesquisadores, educadores e estudantes. Dois exemplos de aplicação desses modelos são apresentados. O modelo detalhado é empregado para analisar o impacto do dimensionamento do capacitor de corrente contínua na geração de harmônicos pelo DSTATCOM. Ao passo que um estudo sobre a influência de um DSTATCOM na estabilidade de geradores de indução conectados diretamente em redes de distribuição é realizado usando o modelo simplificado.

Impacts of AC Generators and DSTATCOM Devices on the Dynamic Performance of Distribution Systems

This paper presents a dynamic study about the influences of ac generators (induction and synchronous machines) and distribution static synchronous compensator (DSTATCOM) devices on the dynamic behavior of distribution networks. The performance of a DSTATCOM as a voltage controller or a power factor controller is analyzed. The impacts of these controllers on the stability and protection system of distribution networks with distributed generators are determined. Computer simulation results show that a DSTATCOM voltage controller can improve the stability performance of induction generators significantly. On the other hand, a DSTATCOM power factor controller may adversely affect the stability performance of synchronous generators. It has also been observed that a DSTATCOM has no influence on short-circuit currents provided by ac generators during faults.

Impacts of dynamic reactive power compensation devices on the performance of wind power generators

This paper investigates the main impacts of dynamic reactive power compensation devices on the performance of induction machine-based wind power generators. The dynamic reactive power compensation devices analysed are the SVC (Static Var Compensator) and the DSTATCOM (Distributed Static Synchronous Compensator). The usage of these devices as a power factor regulator or a voltage regulator is investigated. The technical factors analysed are small-signal voltage stability, transient stability, and interactions with the anti-islanding protection system. The analyses are carried out by using a wind farm composed of 30 units of 1 MW induction generators. Such wind farm is connected to a 60 Hz, 33 kV distribution system. The results are a useful guideline to evaluate which control strategy and device are suitable for a determined application as well as to understand the dynamic interactions that can occur.