Review on power quality solution technology

This paper presents a comprehensive study of various possible solutions for power quality improvement in common applications and supply system. This includes improved power quality converters (IPQC), multi-pulse converters, active compensation, passive compensation and their hybrid configurations. Various configurations and topologies of custom power devices such as DSTATCOM (Distribution Static Compensator), DVR (Dynamic Voltage Restorer) and UPQC (Unified Power Quality Compensator) are also described in detail. Main applications of these devices are for reactive power compensation, harmonic elimination, voltage sag/swell mitigation, voltage regulation, load balancing, neutral current reduction etc. Many such cases of power quality problems have been taken up and suitable solutions have been identified for those cases. As an example, a model of DSTATCOM is developed and its performance is presented for a distribution system feeding nonlinear loads

Mitigation of Power Quality Problems Using Custom Power Devices: A Review

Electrical power quality (EPQ) in distribution systems is a critical issue for commercial, industrial and residential applications. The new concept of advanced power electronic based Custom Power Devices (CPDs) mainly distributed static synchronous compensator (D-STATCOM), dynamic voltage restorer (DVR) and unified power quality conditioner (UPQC) have been developed due to lacking the performance of traditional compensating devices to minimize power quality disturbances. This paper presents a comprehensive review on D-STATCOM, DVR and UPQC to solve the electrical power quality problems of the distribution networks. This is intended to present a broad overview of the various possible DSTATCOM, DVR and UPQC configurations for single-phase (two wire) and three-phase (three-wire and four-wire) networks and control strategies for the compensation of various power quality disturbances. Apart from this, comprehensive explanation, comparison, and discussion on D-STATCOM, DVR, and UPQC are presented. This paper is aimed to explore a broad prospective on the status of D-STATCOMs, DVRs, and UPQCs to researchers, engineers and the community dealing with the power quality enhancement. A classified list of some latest research publications on the topic is also appended for a quick reference

Inductively coupled distributed static compensator for power quality analysis of distribution networks

In this research paper, an inductively coupled distributed static compensator (IC-DSTATCOM) for three phase three wire (3P3W) electric power distribution system (EPDS) is proposed. The contraction of power quality (PQ) was marked as a perilous droop mode bump into direct coupled distributed static compensator (DC-DSTATCOM). To regain the PQ, inductive coupling transformer is assisted in conjunction with DC-DSTATCOM. The system equivalent circuit of IC-DSTATCOM is accomplished by take into account of impedance of both transformer and DC-DSTATCOM to reveal the filtering technique. The filtering icos∅ mechanism is performed by following the generalized mathematical approach using MATLAB/Simulink. A case education is reviewed in detail to illustrate the performance of both DC-DSTATCOM and IC-DSTATCOM. The IC-DSTATCOM is amplified healthier as compared to other in terms of harmonics shortening, good power factor, load balancing, and potential regulation. To examine the effectiveness, simulation outputs of the IC-DSTATCOM with different PQ parameter indices are presented by following the benchmark measure of IEEE-2030-7-2017 and IEC-61000-1 system code

Performances of Six-leg DSTATCOM Topology under Various SRF Algorithms

Six-leg DSTATCOM can be employed for improving the superiority of power in a distribution system. DSTATCOM is the most valuable current harmonic reduction device because of its excellent compliance in active situations. The DSTATCOM has a shunt voltage source inverter (VSI) attached to the common coupling point of power system via the interfacing inductor. In its controllers, the various SRF algorithms such as Conventional SRF, DCC based SRF and ICC based SRF have been adopted due to its easy execution aspects. These algorithms create balanced and sinusoidal supply current, compensate the reactive power, improving the power factor near unity on common coupling point and mitigate harmonic in the supply current. The reference signal for PWM generator is generated using SRF algorithms. A 3-phase 4-wire power system with rectified RC/RL load has been taken for the detailed simulation study. The performances of DSTATCOM topology have been compared under conventional SRF, DCC based SRF and ICC based SRF control strategies in terms of power quality improvement.&nbsp

Combined DC-Link Fed Parallel-VSI-Based DSTATCOM for Power Quality Improvement of a Solar DG Integrated System

In present day power systems, Power Quality (PQ) issues are causing great concern owing to the increased use of power electronic controlled drives and fluctuating and other non-linear loads. This problem is further aggravated by a steady increase in the integration of renewable energy-based Distribution Generation (DG), employing power electronic converters to distribution systems. Custom power devices with suitable control strategies provide an effective solution to these power quality issues. In this work, a typical three-phase distribution system supplying non-linear load and with DG integration is considered. A shunt connected DSTATCOM at PCC of the system is employed to mitigate power quality concerns. Initially, a parallel-VSI based DSTATCOM configuration, employing individual DC-Link and working basically on the principle of current sharing, has been proposed. The analysis is carried out for variable load conditions for PQ enhancement making use of a more effective control theory viz. Instantaneous Real-Reactive Power (IRP) theory for the generation of suitable switching patterns to the individual VSIs of the parallel DSTATCOM. Further, an improvement over the above configuration viz. combined/common DC-Link-fed parallel DSTATCOM is proposed. This configuration has the advantages of minimized sensing elements, reliable operation and low-cost compensation. A similar analysis is carried out for PQ improvement, making use of the same IRP theory with some modifications (known as MIRP theory). The effectiveness of this configuration is established from the simulation results. In all the above cases, the analyses are carried out using MATLAB/Simulink platform and the simulation results are presented in detail. Thus, the proposed parallel VSIs-based DSTATCOM configurations employing suitable control strategies provide effective solutions for power quality issues under varying load conditions in conventional distribution systems

Modelling, Simulation and Fuzzy Self-Tuning Control of D-STATCOM in a Single Machine Infinite Bus Power System

© 2019 Bentham Science Publishers. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.2174/2352096511666180314141205In recent years, demand for electricity has increased considerably, while the expansion of generation and transmission has been very slow due to limited investment in resources and environmental restrictions. Methods: As a result, the power system becomes vulnerable to disturbances and instability. FACTS (Flexible AC Transmission Systems) technology has now been accepted as a potential solution to this problem. This paper deals with the modelling, simulation and fuzzy self-tuning control of a D-STATCOM to enhance the stability and improve the critical fault clearing time(CCT) in a single machine infinite bus (SMIB).A detailed modelling of the D-STATCOM and comprehensive derivation of the fuzzy logic self-tuning control is presented. Results: The dynamic performance of the power system with the proposed control scheme is validated through in a simulation study carried out under Matlab/Simulink and SimPowerSystems toolbox. Conclusion: The results demonstrate a significant enhancement of the power system stability under the simulated fault conditions considered.Peer reviewe

Harmonic mitigation and power quality improvement in utility grid with solar energy penetration using distribution static compensator

Abstract Distribution static compensator is based on power electronic devices technology which is utilized to supply rapid changes in active power as well as reactive power of utility grids. This is useful to achieve corrections in power factor, balancing of load, compensation of current and filtering of harmonics. Therefore, proposed work investigates the improvement of the power quality by utilizing the distribution static compensator, which is equipped by battery energy storage system and interfaced to distribution network with solar photo voltaic (PV) energy integration. In the present study, distribution static compensator is controlled using a control strategy based on the synchronous reference frame theory. Customised IEEE‐13 nodes test system incorporating solar PV generation and distribution static compensator, is utilized to perform the harmonic mitigation and power quality analysis. Disturbances of power quality and harmonics have been investigated due to abrupt changes in the insolation of solar radiation, outage of PV plant from grid and synchronization of PV plant to grid. MATLAB/Simulink environment is utilized to perform the study. Effectiveness of a developed approach is validated by comparing results of simulation with results extracted in real time using real time digital simulator. Results indicate that the developed method is more effective for harmonic mitigation and improving power quality of electrical power in distribution network integrated with solar PV generation. Performance of the approach is compared with the performance of methods reported in the literature to establish the suitability of the method for harmonics mitigation and power quality improvement in grid with solar energy

Performance Analysis of Photovoltaic Fed Distributed Static Compensator for Power Quality Improvement

Owing to rising demand for electricity, shortage of fossil fuels, reliability issues, high transmission and distribution losses, presently many countries are looking forward to integrate the renewable energy sources into existing electricity grid. This kind of distributed generation provides power at a location close to the residential or commercial consumers with low transmission and distribution costs. Among other micro sources, solar photovoltaic (PV) systems are penetrating rapidly due to its ability to provide necessary dc voltage and decreasing capital cost. On the other hand, the distribution systems are confronting serious power quality issues because of various nonlinear loads and impromptu expansion. The power quality issues incorporate harmonic currents, high reactive power burden, and load unbalance and so on. The custom power device widely used to improve these power quality issues is the distributed static compensator (DSTATCOM). For continuous and effective compensation of power quality issues in a grid connected solar photovoltaic distribution system, the solar inverters are designed to operate as a DSTATCOM thus by increasing the efficiency and reducing the cost of the system. The solar inverters are interfaced with grid through an L-type or LCL-type ac passive filters. Due to the voltage drop across these passive filters a high amount of voltage is maintained across the dc-link of the solar inverter so that the power can flow from PV source to grid and an effective compensation can be achieved. So in the thesis a new topology has been proposed for PV-DSTATCOM to reduce the dc-link voltage which inherently reduces the cost and rating of the solar inverter. The new LCLC-type PV-DSTATCOM is implemented both in simulation and hardware for extensive study. From the obtained results, the LCLC-type PV-DSTATCOM found to be more effective than L-type and LCL-type PV-DSTATCOM. Selection of proper reference compensation current extraction scheme plays the most crucial role in DSTATCOM performance. This thesis describes three time-domain schemes viz. Instantaneous active and reactive power (p-q), modified p-q, and IcosΦ schemes. The objective is to bring down the source current THD below 5%, to satisfy the IEEE-519 Standard recommendations on harmonic limits. Comparative evaluation shows that, IcosΦ scheme is the best PV-DSTATCOM control scheme irrespective of supply and load conditions. In the view of the fact that the filtering parameters of the PV-DSTATCOM and gains of the PI controller are designed using a linearized mathematical model of the system. Such a design may not yield satisfactory results under changing operating conditions due to the complex, nonlinear and time-varying nature of power system networks. To overcome this, evolutionary algorithms have been adopted and an algorithm-specific control parameter independent optimization tool (JAYA) is proposed. The JAYA optimization algorithm overcomes the drawbacks of both grenade explosion method (GEM) and teaching learning based optimization (TLBO), and accelerate the convergence of optimization problem. Extensive simulation studies and real-time investigations are performed for comparative assessment of proposed implementation of GEM, TLBO and JAYA optimization on PV-DSTATCOM. This validates that, the PV-DSTATCOM employing JAYA offers superior harmonic compensation compared to other alternatives, by lowering down the source current THD to drastically small values. Another indispensable aspect of PV-DSTATCOM is that due to parameter variation and nonlinearity present in the system, the reference current generated by the reference compensation current extraction scheme get altered for a changing operating conditions. So a sliding mode controller (SMC) based p-q theory is proposed in the dissertation to reduce these effects. To validate the efficacy of the implemented sliding mode controller for the power quality improvement, the performance of the proposed system with both linear and non-linear controller are observed and compared by taking total harmonic distortion as performance index. From the obtained simulation and experimentation results it is concluded that the SMC based LCLC-type PV-DSTATCOM performs better in all critical operating conditions