A TWO-INVERTER STRATEGY TO INTERCHANGE CURRENT IN DISTRIBUTED ENERGY

The suggested plan has elevated reliability, lower bandwidth reliance upon the primary inverter, less pricey because of decrease in filter size, and employ of micro grid power while using the reduced electricity-link current rating for the primary inverter. This paper presents a dual current source inverter (DVSI) plan to enhance the ability quality and sturdiness in the micro grid system. The control calculations are developed according to immediate created component theory (ISCT) to function DVSI in grid discussing and grid injecting modes. The proliferation of power electronics products and electrical loads with unbalanced nonlinear power has degraded the ability quality within the power distribution network these traits make DVSI plan a great choice for micro grid offering sensitive loads. The topology and control formula are validated through extensive simulation and experimental results. The suggested plan includes two inverters, which helps the micro grid to alter power produced using the distributed forces (DERs) and also to compensate the region unbalanced and nonlinear load

POWER EXCHANGING DISTRIBUTED POWER DEVICE TO BALANCE LOCAL LOADS

The suggested plan has elevated reliability, lower bandwidth dependence on the primary inverter, less expensive because of decrease in filter size, and usage of micro grid power while using the reduced electricity-link current rating for that primary inverter. This paper presents a dual current source inverter (DVSI) plan to boost the ability quality and longevity of the micro grid system. The control calculations are developed according to immediate shaped component theory (ISCT) to function DVSI in grid discussing and grid injecting modes. The proliferation of power electronics products and electrical loads with unbalanced nonlinear power has degraded the ability quality within the power distribution network these functions result in the DVSI plan an encouraging choice for micro grid offering sensitive loads. The topology and control formula are validated through extensive simulation and experimental results. The suggested plan is composed of two inverters, which allows the micro grid to switch power produced through the distributed energy sources (DERs) also to compensate the neighborhood unbalanced and nonlinear load

Analysis and Simulation of a PWM Converter Designed to Perform Harmonic Compensation and Maximum Power Point Tracking in a Grid-Connected Solar System

Solar energy is arguably the most promising response to the challenge of generating power in a clean and renewable way. However, there are many technical challenges that must be overcome before this alternative becomes able to replace the non-renewable sources in use today. For instance, currently there is no way to efficiently store the energy generated by photovoltaic panels while the sunlight is shining, which is crucial if energy generated by PV panels is to be used during the night or in a cloudy day. While those problems remain unsolved, one of the best ways available for using solar energy is to couple PV panels with the electric grid in order to minimize the use of non-renewable sources for power generation. This thesis presents and discusses the use of a power electronics based converter designed to couple a PV panel to the power grid. The converter in this case is able to extract the maximum power possible from the panel regardless of the environment conditions and perform harmonic compensation at the same time. The thesis will be structured as follows. First, the theoretical foundation for analysis and design of the aforementioned converter will be presented. Then, the converter will be modeled. Using the model, a control system will be designed to enforce the desired behavior. Last, the whole system will be simulated in Matlab/Simulink^R and the results will be analyzed

Sag effects on protection system in distributed generation grids

Distributed Generators (DGs) are sensible to voltage sags, so the protection devices must trip fast to disconnect the faulted part of the grid. The DG disconnection will not be desirable in the near future with a large penetration, so it will be necessary to lay down new requirements that should be based on avoiding unnecessary disconnections. Therefore, to prevent unnecessary tripping when inverter-based DGs are connected to the Medium Voltage (MV) grid, reliable and effective protection strategies need to be developed, considering the limited short-circuit current contribution of DG. The initial goal of this study is to employ different possible control strategies for a grid-connected inverter according to the Spanish grid code and to analyze the output voltage behavior during symmetrical and unsymmetrical voltage sags. The analytical development of the proposed strategies shows the impacts of the sag on currents, voltages, active and reactive powers. Another goal of this research is to propose a protection strategy based on Artificial Intelligence for a radial or ring distribution system with high DG penetration. The protection strategy is based on three different algorithms to develop a more secure, redundant, and reliable protection system to ensure supply continuity during disturbances in ring and radial grids without compromising system stability. In order to classify, locate and distinguish between permanent or transient faults, new protection algorithms based on artificial intelligence are proposed in this research, allowing network availability improvement disconnecting only the faulted part of the system. This research introduces the innovative use of directional relay based on a communication system and Artificial Neural Network (ANN). The first algorithm, Centralize algorithm (CE), collects the data from all the PDs in the grid in the centralized controller. This algorithm detects the power flow direction and calculates the positive-sequence current of all the PDs in the grid. Significant benefits of this system are that it consolidates the entire systems security into a single device, which can facilitate system security control. However, the CE will not pinpoint the exact location of the fault if there is any loss of information due to poor communication. Therefore, the systems redundancy can be improved by cooperating with a second algorithm, the Zone algorithm (ZO). ZO algorithm is based on zone control using peer-to-peer connectivity in the same line. The faulty line in that zone may be identified by combining the two PDs data on the same line. The most relevant advantage of this algorithm is its flexibility to adapt to any grid modification or disturbance, even if they are just temporary, unlike the CE, which is fixed to the existing grid configuration. The third protection algorithm, Local algorithm (LO), has been proposed without depending on the communication between the PDs; then, the protection system can work properly in case of a total loss of communication. Each PD should be able to detect if the fault is located in the protected line or another line by using only the local information of the PD. According to the type of fault and based on local measurements at each PD of abc voltages and currents, different algorithms will be applied depending on the calculation of the sequence components. The main advantage of this algorithm is the separate decision of each PD, and avoiding communication problems. In case of radial grids, both mechanical breakers and Solid State Relays (SSRs) are used to verify the protection strategies, and in the case of ring grids, mechanical breakers are used, due to the limitations in required voltage difference of SSR. The proposed protection algorithms are compared with conventional protections (Overcurrent and Differential) protections to validate the contribution of the proposed algorithms, especially in reconfigurable smart grids.El objetivo inicial de este estudio es emplear diferentes estrategias de control posibles para un inversor conectado a la red segun el código de red español y analizar el comportamiento de la tensión de salida durante caídas de tensión simétricas y asimétricas. El desarrollo analítico de las estrategias propuestas muestra los impactos de los huecos de tensión en las corrientes, tensiones, potencias activas y reactivas. Otro objetivo de esta investigación es proponer una estrategia de protecclón basada en lnteligencia Artificial para una red del Sistema de Distribución, radial o en anillo, con elevada penetración de Generación Distribuida. La estrategia de protección se basa en tres algoritmos diferentes para desarrollar un sistema de protección más seguro, redundante, y fiable, que asegure la continuidad de suministro durante perturbaciones en redes radiales o en anillo sin comprometer la estabilidad del sistema. Para clasificar, localizar y distinguir entre faltas permanentes o transitorias, se proponen en este trabajo nuevos algoritmos de protección basados en inteligencia artificial, permitiendo la mejora de la disponibilidad de la red, al desconectar sólo la parte del sistema en falta. Esta investigación introduce la innovación del uso del rele direccional basado en un sistema de comunicación y Redes Neuronales Artificiales (ANN). El primer algoritmo, Algoritmo Central (CE), recibe los datos de todos los PDs de la red en un control central. Este algoritmo detecta la dirección de flujo de cargas y calcula la corriente de secuencia positiva de todos los PDs de la red. El entrenamiento de ANNs incluye variaciones en la corriente de cortocircuito y la dirección del flujo de potencia en cada PD. Los beneficios mas significativos de este sistema son que concentra la seguridad total del sistema en un único dispositivo, lo que puede facilitar el control de la seguridad del sistema. Sin embargo, el CE no determinara con precisión la localización exacta de la falta si hay alguna perdida de información debida a una pobre comunicación. Por lo tanto, la redundancia del sistema se puede mejorar cooperando con un segundo algoritmo, el algoritmo de Zona (ZO). El algoritmo ZO se basa en un control de zona usando la conectividad entre dispositivos de protección de una misma línea. La línea en falta en esa zona puede identificarse combinando los datos de los dos PDs de la misma línea.. La ventaja mas relevante de este algoritmo es su flexibilidad para adaptarse a cualquier modificación de la red o perturbación, incluso si sólo son temporales, a diferencia del CE, que se ha adaptado para la configuración de la red existente. El tercer algoritmo de protección, algoritmo Local (LO), ha sido propuesto sin dependencia de la comunicación entre PDs; por lo tanto, el sistema de protección puede operar correctamente en el caso de una pérdida total de comunicación. Cada PD debe poder detectar si la falta esta ubicada en la línea protegida o en otra línea, utilizando sóIo la información local del PD. Según el tipo de falta, y en base a medidas locales en cada PD, de tensiones y corrientes abc, se aplican diferentes algoritmos en función del cálculo de las componentes simétricas. La principal ventaja de este algoritmo es la actuación por separado de cada PD, evitando los problemas de comunicación. En el caso de las redes radiales, se utilizan tanto interruptores mecánicos como réles de estado sóIido (SSR) para verificar las estrategias de protección, y en el caso de las redes en anillo se utilizan interruptores mecánicos, debido a las limitaciones de tensión para su conexión. Los algoritmos de protección propuestos se comparan con protecciones convencionales (Sobrecorriente y Diferencial) para validar la contribución de los algoritmos propuestos, especialmente en redes inteligentes reconfigurables.Postprint (published version