Two-leg three-phase inverter control for STATCOM and SSSC applications

Flexible ac transmission systems (FACTS) devices are attracting an increasing interest both in power system academic research and in electric utilities for their capabilities to improve steady-state performance as well as system stability. Several converter topologies for FACTS applications have been proposed in the recent literature, even if those based upon voltage source inverters (VSI) seem to be more attractive due to their intrinsic capability to rapidly respond to network changes such as perturbations subsequent to a fault and their property of being immune to resonance problem. In this paper, a new topology for inverter-based FACTS is proposed. This configuration, employing a two-leg three-phase inverter is employed for both series and parallel-connected reactive power compensators. The converter utilizes a modular topology for allowing a satisfaction of electronic components rating. A control strategy based on variable structure control technique with sliding mode is employed to track appropriate reference quantities. Design and control, as well as good tracking performances, are also verified through numerical simulations

Reactive Power Control in Power System using Modified UPFC

The power system is a exceptionally nonlinear system that works in an always showing signs of change condition, loads, generator yields, topology and key working parameters changes consistently. The stability of the system depends on the nature of the disturbance as well as the initial operating condition. The power congestion known as the limitations to how much power can be transferred across a transmission interfaces and further that there is an incentive to actually desire to transfer more power. The old approach was to correct congestion lies in reinforcing the system with additional transmission capacity. Although easy to perform, this approach is complex, time consuming and costly. It is ending up noticeably progressively hard to get the licenses to building new transmission passages, or even grow existing ones. This issue can be solved by introducing Facts devices in the transmission system. Facts Devices play an imperative part in controlling the reactive and active power flow to the power network and thus both the system voltage variances and transient stability. Among Facts device Unified Power Flow Controller (UPFC) is the most versatile and complex power electronic equipment which can increase reliability and can serve as an alternative to new investments in overhead lines, which are difficult due to a lack of public support. The proposed work is based on control of reactive power in power system utilizing modified Unified Power Flow Controller (UPFC). The impact of customary UPFC and modified UPFC on the power flow of transmission lines were analyzed

Новое семейство преобразователей напряжения с низким уровнем гармонических искажений с использованием соединенных индуктивностей

У даній статті представлений новий підхід до багатоімпульсних перетворювачів напруги, зокрема інверторів напруги і матричних перетворювачів на основі кількох типових ідентичних модулів, з'єднаних паралельно з використанням Inductive Current Splitters/Mergers. Такі механізми призводить до зниження напруги спотворення при низькій частоті перемикання. Пропоновані нові механізми була підтверджені за допомогою моделювання. Лабораторні моделі 18- і 24-імпульсних 3-рівневих перетворювачів напруги були також досліджені експериментально. Результати моделювання і лабораторних випробувань експериментальних моделей представлені в роботі.This paper presented a novel approach to the multipulse voltage converters (VC), especially voltage source inverters (VSI) and matric converters (MC) based on several typical identical modules connected in parallel using Inductive Current Splitters/Mergers. Such arrangements resulting in lower voltage distortions at extremely low switching frequency. Proposed new arrangements was validated by simulation. Laboratory models of 18- and 24-pulse 3-level VSI arrangements was also investigated experimentally. Results of simulation and laboratory tests of experimental models are presented in the paper.В данной статье представлен новый подход к многоимпульсным преобразователям напряжения, в том числе инверторам напряжения и матричным преобразователям на основе нескольких типовых идентичных модулей, соединенных параллельно с использованием Inductive Current Splitters / Mergers. Такие механизмы приводит к снижению напряжения искажения при низкой частоте переключения. Предлагаемые новые механизмы были подтверждены с помощью моделирования. Лабораторные модели 18- и 24-импульсных 3-уровневый преобразователей напряжения были также исследованы экспериментально. Результаты моделирования и лабораторных испытаний экспериментальных моделей представлены в работе

A Five Level Modified Cascaded H-Bridge Inverter STATCOM for Power Quality Improvement

Multilevel converters have received serious attention on account of their capability of high voltage operation, high efficiency, and low electromagnetic interference. It has many advantages compared to conventional two-level inverters such as high dc-link voltages, reduced harmonic distortion, fewer voltage stresses, and low electromagnetic interferences. The multilevel converters have been used for STATCOM widely as it can improve the power rating of the compensator to make it suitable for medium or high-voltage high power applications. While deploying multilevel STATCOMs, designer’s role is to reduce the number of switching devices since, the total switching losses are proportional to the number of switching devices. The reduction in the count of switching devices also reduces the size and cost. In this paper, a five-level modified cascaded H-bridge inverter STATCOM is proposed for mitigation of harmonics. Modified Five-level CHB configuration is the most suitable as with lesser number of switches, give better performance resulting in a compact system. The PQ theory-based controller is developed for control of STATCOM operation. MATLAB simulation results are presented to demonstrate mitigation of harmonics

Five Level Flying-Capacitor Multilevel Converter Using Dynamic Voltage Restorer (DVR)

This paper deals with dynamic voltage restorer (DVR) controlled by a five-level flying-capacitor multi level converter. To decrease the power-quality disturbances in distribution system, such as voltage imbalances, harmonic voltages, and voltage sags. The organisation of this paper has been divided into three parts; the first one eliminates the modulation high-frequency harmonics using filter increase the transient response. The second one deal with the load voltage; and the third is flying capacitors charged with balanced voltages. The MATLAB simulation results effectively for five level flying capacitor multilevel converters charged with balanced voltage regulation

A Modular Multilevel Flying Capacitor Converter-based STATCOM for Reactive Power Control

This paper presents a simulation study for a built prototype of modular multi-level flying capacitor cascade converter as a STATCOM. The converter modulation scheme applied is based on Phase Shifted PWM and the two scenarios which require compensation are investigated to verify this topology. The two scenarios are PCC voltage regulation and unity power factor correction through reactive power compensation. Simulation results verify the performance of the chosen topolog

A Multi-Processor Control System Architecture for a Cascaded StatCom with Energy Storage

This paper presents a multi-processor control system for a general purpose five-level cascaded inverter for real time power system applications. Practical design considerations for the digital controller architecture as well as the power converter are discussed and a 3 kVA laboratory prototype is presented. As a case study, a StatCom with battery energy storage was implemented on this multi-processor controlled inverter system. To eliminate the troublesome PI parameter tuning and the limitation of small signal models, which exist in conventional control for StatComs, a new and simple control method based on large signal model was designed to realize four-quadrant power injections into a grid. Experimental results are provided to support the proposed concept

VSC topology comparison for STATCOM application under unbalanced conditions

This paper compares the performance of four different power electronic converter topologies, which have been proposed for STATCOM applications. Two of the topologies are Modular Multilevel Cascaded Converters (MMCC), whilst the remaining circuits utilize magnetic elements and an open-winding transformer configuration to combine individual power modules. It is assumed that the STATCOM has to work under unbalanced conditions, so that it delivers both positive and negative sequence currents. Simulation studies for the four topologies have been carried out using the simulation tool Saber

Modelamiento y simulación de un controlador de flujo de potencia unificado para estudios eléctricos en régimen permanente

El presente artículo muestra un modelo para el estudio eléctrico en régimen permanente de un controlador de flujo de potencia unificado (UPFC), utilizando el software matemático MATLAB. Para obtener los flujos de energía en el SEP, se utilizan métodos iterativos convencionales, como el método de Newton Raphson, que se modificará para agregar un dispositivo UPFC en la red eléctrica. El propósito de la implementación del algoritmo de resolución es evaluar el impacto que el dispositivo UPFC tiene en la red de transmisión, especialmente en el nivel de voltaje en los nodos y la capacidad de carga de las líneas de transmisión.The present article shows a model for the electric study in permanent regime of a unified power flow controller (UPFC), using MATLAB mathematical software. To obtain the energy flows in the SEP, conventional iterative methods are used, such as the Newton Raphson method, which will be modified to add a UPFC device in the electric network. The purpose of the implementation of the resolution algorithm is to evaluate the impact that the UPFC device has on the transmission network, especially on the voltage level at the nodes and the load capacity of the transmission lines