Designing a new smart IED for detecting and clearing faults in solar networks

In recent decades, use of solar systems is developed and it is used in many small applications even in home appliances. DC micro grids with centralized solar generation are widely interested for various power applications due to their advantages over traditional AC power distribution systems with respect to power density and power distribution efficiency. On the other hand, protection of these kind of systems against faults are hard to diagnose. It is difficult to extinguish these arc faults via conventional circuit breakers due to the lack of natural zero-crossing of DC current. To overcome of this problem, this article proposed a new smart relay for detecting and clearing faults in solar networks that can gather data of all elements in grid and transmit data to a central control system in a SCADA system by using IEC61850 standards

DC microgrid in residential buildings

DC microgrid in residential building

System configuration, fault detection, location, isolation and restoration: a review on LVDC Microgrid protections

Low voltage direct current (LVDC) distribution has gained the significant interest of research due to the advancements in power conversion technologies. However, the use of converters has given rise to several technical issues regarding their protections and controls of such devices under faulty conditions. Post-fault behaviour of converter-fed LVDC system involves both active converter control and passive circuit transient of similar time scale, which makes the protection for LVDC distribution significantly different and more challenging than low voltage AC. These protection and operational issues have handicapped the practical applications of DC distribution. This paper presents state-of-the-art protection schemes developed for DC Microgrids. With a close look at practical limitations such as the dependency on modelling accuracy, requirement on communications and so forth, a comprehensive evaluation is carried out on those system approaches in terms of system configurations， fault detection, location, isolation and restoration

A Hardware-in-Loop Simulation of DC Microgrid using Multi-Agent Systems

Smart-grid is a complex system that incorporates distributed control, communication, optimization, and management functions in addition to the legacy functions such as generation, storage, and control. The design and test of new smart-grid algorithms require an efficient simulator. Agent-based simulation platforms are the most popular tools that work well in the control and monitoring functionalities of the power electric network such as the microgrid. Most existing simulation tools necessitate either simulated or static data. In this paper, we propose a hardware-in-loop simulator for de-microgrid. The simulator reads the power generated by the PV panels and the battery SoC using Raspberry PI. A physical agent that runs on Raspberry PI sends the real-time data to a de-microgrid simulator that runs on a PC. As a proof of concept, we implemented a load-shedding algorithm using the proposed system

Diseño de un sistema de protecciones eléctricas basado en contactores como método de protecciones ante fallas en sistemas de distribución nodales DC

El documento propone usar contactores de arco como alternativa para proteger micro-redes (MR) nodales. Se revisa la importancia de estas redes y sus componentes, los tipos de micro-redes y los trabajos previos establecidos para protección de estas redes. Se estudia los principales desafíos técnicos que presenta la protección de redes con componentes DC, en especial la protección de elementos cuya corriente de falla está limitada por componentes electrónicos que permiten la conversión de energía. El diseño de la protección con contactores, así como la estructura de control que está basada en trabajos previos, y se plantea como una idea válida debido a su costo reducido si se compara con otras opciones; se pone a prueba por medio de técnicas de simulación de una micro-red que se basa en el sistema IEEE14 y que está modificada para ser una red hibrida AC/DC con componentes de generación solar, cargas, batería y conversores de energía. En los componentes mencionados se realizan ensayos de fallas, de tal forma de poder analizar el comportamiento del sistema de protecciones, en especial la forma de onda de la corriente de falla en los puntos de revisión, así como el tiempo de despeje que tiene cada falla presentada.The present paper proposes to employ arc contactors as alternative to protect nodal micro-grids (MR). The authors made a review of the importance of this type of network. It is also reviewed the parts and types of micro-grids. The previous researches on micro-grid protection are also boarded. The main technical challenges to protect important components of a microgrids are also mentioned. The most challenging aspects of DC grid protection are considered. A review of the protection of devices that have a fault current value constraint due to electronic devices that allow the energy conversion. Next, the design of protection with contactors and the control structure based in some previous researches are tested. This is a valuable idea due to the low cost compared with other alternatives. These tests are accomplished through simulation techniques of a micro-grid based on IEEE14 test grid. The structure includes solar power, converters and storage media connected to the grid that is hybrid. In the afore-mentioned parts failure tests are performed. The tests allow to analyze the protection scheme behavior. The focus of the analysis is the waveform of fault current on the nodes of the network and the clearance time of each proposed fault

Óptimo control terciario para el sistema de almacenamiento de energía mediante baterias acopladas a micro-redes en DC usando programación lineal entera mixta

El presente trabajo de investigación, propone un óptimo control terciario de Micro-redes (MR) en Corriente Continua (CC), basado en programación lineal entera mixta. En efecto, el estudio se fundamentará en alcanzar un control terciario en MR de CC para la estabilidad y confiabilidad del sistema establecido. Las Micro-redes se caracterizan por obtener sistemas que complementan la generación de electricidad y el acopio energético, por ende, son capaces de aminorar las pérdidas de transmisión, y de esta forma mejorar la eficiencia. Naturalmente, se encuentran enlazadas a una red central convencional, tomando en cuenta que se pueden desconectar, permitiendo una función autónoma. Por ende, el sistema establecerá que la MR podrá trabajar de forma sólida dentro de los estándares establecidos, tomando en cuenta que se realizará en un sistema robusto, por lo tanto, su gestión eléctrica tendrá una estabilidad optima en el interior del sistema. De manera que, para la simulación y visualización de resultados, se empleara las herramientas matemáticas tales como: Matlab / Simulink.The present research work proposes an optimal tertiary control of Micro networks (MR) in Direct Current (CC), based on mixed integer linear programming. Indeed, the study will be based on achieving a tertiary control in DC MR for the stability and reliability of the established system. Micro-grids are characterized by obtaining systems that complement electricity generation and energy storage, therefore, they are capable of reducing transmission losses, and thus improve efficiency. Naturally, they are linked to a conventional central network, taking into account that they can be disconnected, allowing an autonomous function. Therefore, the system will establish that the MR will be able to work solidly within the established standards, taking into account that it will be carried out in a robust system, therefore, its electrical management will have optimal stability within the system. So, for the simulation and visualization of results, mathematical tools such as: Matlab / Simulink will be use

Electricity market design requirements for DC distribution systems

DC distribution systems (DCDS) connect local generators and loads directly. By avoiding unnecessary losses in AC-DC conversion, DCDS offers higher energy efficiency. Since different parties in a DCDS may have conflicting goals, matching between power supply and demand should be done with carefully designed allocation rules and monetary transfers, such that no one prefers to act otherwise than the outcome of the allocation. This paper reveals DCDS' unique operational requirements and indicates the challenges and opportunities they pose to market design. A design framework is introduced into DCDS electricity market, incl. tradable services, design goals, market participants, design options and performance criteria. We review the existing market models for AC and DC distribution systems and point out the direction for future work