Evolution of Islanding Detection Methods for Microgrid Systems

A microgrid is a representation of controllable electrical power network, which comprises the distributed generation (DG) such as micro-hydro, wind turbines, photovoltaic arrays, bio-mass generation, battery energy storage systems (BESSs), and a group of interconnected load. A typical microgrid can be operated in either grid connected or island mode. The issue of unintentional islanding in microgrid is a major challenge for power engineers as it may harm the service personnel working during maintenance or restoration of the main grid. In literature, various passive, active, and hybrid islanding detection methods (IDMs) have been developed and implemented by researchers/engineers. In this chapter, the proposed IDMs from the recent literature have been analyzed and briefly discussed. The primary requirement of IDMs is fast and accurate detection of main grid failure and should not deteriorate the power quality of distribution networks.

PMU Placement Optimization for Fault Observation Using Different Techniques

This chapter presents different techniques for obtaining the optimal number of the phasor measurement units (PMUs) that may be installed in a smart power grid to achieve full network observability under fault conditions. These optimization techniques such as binary teaching learning based optimization (BTLBO) technique, particle swarm optimization, the grey wolf optimizer (GWO), the moth-flame optimization (MFO), the cuckoo search (CS), and the wind-driven optimization (WDO) have been developed for the objective function and constraints alike. The IEEE 14-bus benchmark power system has been used for testing these optimization techniques by simulation. A comparative study of the obtained results of previous works in the literature has been conducted taking into count the simplicity of the model and the accuracy of characteristics.

Role of Smart Metering and Implementation Issues in Smart Grid

Smart grid provides the digital technology that allows for two-way communication between the utility and the customers. The smart grid consists of controls, computers, automation, and new technologies and equipment working together. The smart grid will move the energy industry into a new era of reliability, availability, and efficiency with economic and environmental health. A smart meter plays a major role in the smart grid and it is an electronic device that measures and records the energy consumption. It enables two-way communication between the meter and the supplier through advanced metering infrastructure (AMI). The mode of communication is enabled by either wireless or wired. The wireless communication includes Wi-Fi, wireless mesh networks, Zig Bee, cellular communications, and low power range Wi-Fi. This chapter deliberates about the evolution of electricity metering, major components of smart meter, communication infrastructure and protocols for smart metering, demand-side integration, recent developments, issues faced and solutions, merits and demerits.

Application of Synchro-Phasor Measurement Unit in Smart Grid Including Renewable Energy

Renewable energy is one of the most abundant energies in our planet. In order to satisfy the world demand of electrical energy, solar and wind energy may be used. Identical to all other types of power generation plants, the integration of these renewable energy sources in smart power grid has an impact on its operation. Thus, when the electrical power is injected into the power grid by these energy sources, the system electrical parameters must be well monitored for synchronization purpose. This can be accomplished with the aid of synchro-phasors measurement units. The phase angle of the utility is a critical parameter for the operation of power devices feeding power into the grid such as PV and wind energy inverters. There are many techniques to obtain the grid phase angle such as the zero-crossing detection and the orthogonal phase locked loop. This research work discusses the use of PMUs (Phasor Measurement Unit) for providing this important parameter to system synchronization in the case of high penetration of solar or wind energy in the power grid.

Decentralized Energy Management System Enhancement for Smart Grid

In these last decades, electrical power grids become more intelligent. Hence, sophisticated software and hardware were introduced to the power grid, which makes it a smart grid. This chapter is an introduction on smart-grid technology; thus, microgrids are explained, and the use of multiagent system in centralized/decentralized energy management systems are discussed and compared. Smart agents are an emerging technology for decentralized computation and data storage. Hence, in this chapter, decentralized energy management system is created basing on multi-agent system technique where sources and loads are considered as separated agents each of them. After that, these sources and load create a microgrid and each microgrid can be considered as an agent. The work proposes an approach for load supplying optimization to decrease the microgrid cost and enhance its efficiency.

Phasor Measurement Improvement Using Digital Filter in a Smart Grid

During a transient operation condition of power smart grid, line current may include unwanted components that may cause unnecessary tripping of protection system. The disturbance mainly appears in a form of harmonics and sub-harmonics. In this case of signal waveforms including harmonics, the low pass filter may be used. However, this type of filter does not provide the ability to reject sub-harmonics. This chapter presents the digital filtering design issue based on optimization approach for removing sub-harmonics and hence improving the measurement. The first point of view is to reach an unified accurate phasor measurement algorithm that is immune to nearly all disturbances (sub-harmonics) in power grid including FACT devices and renewable energy sources, simultaneously with required speed of convergence. The second point focuses on reducing the computational requirement and algorithm complexity through designing recursive digital filter with reduced order.

PMU Phasor Estimation Using Different Techniques

Many models of phasor measurement units (PMU) have been implemented; however, few dynamic models have been developed when the power system parameters change. It is necessary to use a method that can somehow estimate the frequency and correct the phasors. The conventional way to determine frequency is to detect zero crossings per unit time. However, this method has many drawbacks such as high cost and low accuracy. Also, after the frequency determination, the phasor should be corrected by suitably modifying the algorithm without omitting any data. This chapter presents different estimation techniques such as discrete Fourier transform (DFT), smart discrete Fourier transform (SDFT) that may be used to estimate the phasors. These estimated values would be incorrect if the input signals are at an off-nominal frequency and the phase angles would drift away from the true values. To correct this issue, first of all, the off-nominal frequency has been estimated using different techniques such as least error squares and phasor measurement angle changing, and then it is used to correct the phasors.

Data and Communication Infrastructure in Smart Grids

The communication infrastructure constitutes the key element in smart grids. There have been great advances to enhance the way data is communicated among the different smart grid applications. The aim of this chapter is to present the data communication part of the smart grid with some pioneering developments in this topic. A succinct review of the state of art projects to improve the communication link is presented. An illustrative simulation using LABVIEW is included with a proposed idea of introducing some newly technologies involved in the current and future generations of wireless communication systems.

Smart Grids and Hybrid Energy Storage Systems

It is very important that the installed renewable energy system should produce the maximum power outputs with minimum costs, and that can only be achieved with the selection of the best optimization technique applied for the best control strategies along with the introduction of the hybrid energy storage systems (HESS). This chapter presents some optimization techniques applied in control strategies for hybrid energy storage systems in distributed renewable energy systems. The integration of energy production and consumption component through the smart grid concept enables increased demand response and energy efficiency. Hybrid energy storage systems and their applications in the renewable energy systems are extensively discussed besides control strategies involved. The storages systems will play an important role in future related to smart grid.

Implementation of Load Control for Smart Metering in Smart Grids

The conventional energy meters are not suitable for long operating purposes as they spend much human and material resources. Smart meters, on the other hand, are devices that perform advanced functions including electrical energy consumption recording of residential/industrial users, billing, real-time monitoring, and load balancing. In this chapter, a smart home prototype is designed and implemented. Appliances are powered by the grid during daytime, and a photovoltaic panel stored power during the night or in case of an electricity outage. Second, consumed power from both sources is sensed and further processed for cumulative energy, cost calculations and bill establishment for different proposed scenarios using LABVIEW software. Data are communicated using a USB data acquisition card (DAQ-USB 6008). Finally, a simulation framework using LABVIEW software models four houses each equipped with various appliances. The simulator predicts different power consumption profiles to seek of peak-demand reduction through a load control process.