Hierarchical Control Of Droop Controlled Ac And Dc Microgrids A General Approach Toward Standardization

Given the challenges encountered while employing conventional electrification methods, micro-grids are being seen as an alternative for providing electricity through a decentralised renewable energy generation and distribution. Decentralised electricity generation signifies ‘an electric power source connected directly to the distribution network or on the customer’s side of the meter’ (Gurtoo & Lahiri n.d.: 17). Micro-grids have the potential for improving energy access and can play a

The significant increase in penetration of renewable energygeneration is expected to affect the operational aspects of powersystems and more specifically isolated micro grids that mainly relyon renewable energy sources. Indeed, the issue of UC schedulesand real-time dispatch of a micro grid with controllable DGs is morecomplicated in the presence of high wind and solar generation pen-etration. To address these operational challenges, it is necessaryto manage the variability and uncertainty associated with theseenergy sources. It has become clearer than ever that a flexiblemicro grid is vital. In this paper, a comprehensive stochastic mathe-matical model has been developed to enable operation interactionof DERs under uncertainty in islanded micro grids. Hence prob-abilistic coordination of DERs on micro grid operations has beenexamined with respect to their independent presence and withconsideration of the hourly interruption cost for residential, com-mercial, and industrial customers in order to determine the optimalprobabilistic interruptible load, if required. The simulation resultsshow that

Summary: At present, most distributed renewable energy systems produce direct current (DC) electricity which is then inverted to alternating current (AC) and fed into the electric grid. Simultaneously, many modern building loads and storage systems use rectifiers to convert AC grid electricity to DC for use at the load or battery. Onsite use of renewable energy production therefore requires two energy conversions: DC/AC at the point of generation and AC/DC at the load. The Bosch DC Building Scale Microgrid Platform (DCBMP) offers significant benefits relative to conventional AC grid systems by distributing as much solar power as possible to DC loads/storage, and then inverting only the excess power to AC for AC loads and export to the grid. The DCBMP maximizes the utilization of solar energy on-site, smooths the volatility of the PV output, increases the load and storage efficiencies and minimizes dependence on grid-based electricity. The proposal incorporates long-life (20-25 years), commercially ready technology, increasing energy efficiency and improving energy security. These features are provided at a low up-front investment when compared to conventional AC-based systems, enabling a levelized cost of electricity (LCOE) less than $0.14/kWh by 2020 for behind-the-meter PV and storage systems and a lower total cost of ownership for the DC loads and DC resources as compared to other approaches, while providing export power to the utility grid through smart inverter

Generally, smart grids technologies can be put into four functional categories: Information collectors; information assemblers, displayers, and assessors; information-based controllers and energy resources. Smart grids collected data from various types of sensors. These sensors measure performance-related characteristics of electricity system components. Assessors are used to analysis and display the information they received from the devices. The information-based controllers devices will use the information that they received to control the other devices behavior to achieve the goal. Energy or power resources include the technologies that can used to generate, store, or reduce demand for electricity.

This paper proposes a new real and reactive power coordination controller for a unified power flow controller (UPFC). The basic control for the UPFC is such that the series converter of the UPFC controls the transmission line near the micro grid real/reactive power flow and the shunt converter of the UPFC controls the UPFC bus voltage/shunt reactive power and the DC link capacitor voltage. In steady state, the real power demand of the series converter is supplied by the shunt converter of the UPFC. To avoid instability/loss of DC link capacitor voltage during transient conditions, a new real power coordination controller has been designed. A new PSO based reactive power coordination controller has been designed to limit excessive voltage excursions during reactive power transfers. Matlab simulation results have been presented to show the improvement in the performance of the UPFC control with the proposed real power and reactive

Microgrid as an aggregator manages power scheduling of DERs and RESs to serve sustainably and reliably through energy management system (EMS) [4], [5]. Employing EMS, microgrid not only alleviates undesirable impacts of intermittencies pertained to RESs, DERs and load, but also provides secure energy services according to smart grid provisional objectives [6],[7]. EMS is in charge of synchronization with the main grid, voltage and frequency control through power balancing and preserving secure operational margins [8],[9],[10],[11],[12].

Abstract—The traditional energy networks to smart grids transformation can help in improving the reliability, performance and manageability.An efficient and real-time scheme to detect FDI(False Data Injection) attacks in smart grids, by exploiting spatial-temporal correlations between grid components. False data injection attacks have recently been introduced as an important class of cyber attacks against smart grids’ wide area measurement and monitoring systems. Once the attack is been detected, the system can take preventive action and alert the manager to take preventative action to sense the risk and to limit the risk. Defensive strategies is been presented against such attacks.

Abstract: This paper presents stochastic synchronization of distributed energy resources (DERs) operation in an islanded micro grid in light of uncertainties. In doing so, a comprehensive stochastic mathematical model is developed which incorporates a set of valid probable scenarios for the uncertainties of load and irregularity in wind and solar generation sources. The uncertainty is addressed through a combination of a stochastic optimization model and additional reserve requirements. The model also includes hourly interruption costs for a variety of customer types as a means of determining the optimal stochastic interruptible load whose reliability-based value is very low to enable it to be shed if necessary. A study is carried out using a benchmark micro grid; numerical results demonstrate that coordinated operation of DERs brings prominent benefits in terms of expected operation costs and system security. This stochastic

The division of the grid into productive sub-systems– so-called MGs, which integrate distributed generation (DG) for local demand – has been proposed to increase manageability and reduce transportation losses [1]. MG can be either connected to other MGs or the main grid for energy exchange or run in island mode as circumstances or economics dictate [2, 3]. The generating units in MGs can either be conventional generators or renewable energy sources (RESs) such as wind turbine (WT) [4] and photovoltaic (PV) systems [5].

In the traditional distribution network, the systems are designed and controlled autonomously. Hence a fault at a system will have serious problem and need immediate rectification. But, rectification of these problems is very difficult. More due to the increase in prices of fossil fuel which are the main cause for generating electricity. Thus, centralized control and integrating their functions is a crucial problem faced in the traditional distribution network. To overcome these issues, there comes Information and communication Technology (ICT) to integrate all the important elements in a distribution system. This develops an environment at distribution level, which is controlled and integrated called “smart grid” which bring up to the date where the electricity generated is transported, distributed by optimizing the system’s economy and the improving the system’s capability to spring back into shape.

Abstract—To meet the Electric Power demands of a fast expanding economy, smart grid (SG) are expected to have reliable, efficient, secured and cost-effective power management system. Additionally, energy demands from the users change dynamically in different time-periods (such as on-peak , and off-peak) , which required dynamically availability

In order to identify one major issue in smart grids design, we propose a thought experiment:

Voltage control and reactive power compensation in a distribution network with embedded wind energy conversion system (WECS) represent main concern of this paper. The WECS is of a fixed speed/constant frequency type that is equipped with an induction generator driven by an unregulated wind turbine. The problem is viewed from short term (10 seconds) and mid-term (10 minutes) time domain responses of the system to different wind speed changes. Being disturbed by a variable wind speed, the WECS injects variable active and reactive power into the distribution network exposing nearby consumers to excessive voltage changes. In the FACTS-based solution

Abstract: Smart grid technology is the combination of existing electrical architecture i.e power generation, switchgear, power systems and digital technologies which provides smart, efficient, reliable and cost effective ways to distribute electricity. It makes optimal use of power by monitoring, analysis, control, and provides flexible distribution to maximize the throughput of the electrical system.

A smart grid is an evolved grid system that manages electricity demand in a sustainable, reliable and economic way, built on advanced metering infrastructure (AMI) and tuned to facilitate the integration of all involved. Smart grids provide more electricity to meet rising demand, increase reliability and quality of power supplies, increase energy efficiency, able to integrate low carbon energy sources into power networks. Smart grids possess demand response capacity to help balance electrical consumption with supply, as well as the potential to integrate new technologies to enable energy storage devices and the large-scale use of electric vehicles. Electrical systems will undergo a foremost advancement, improving consistency and reducing electrical losses, expenditures and maintenance costs. A smarter grid will provides better control over