Bhargav Appasani

Optimal Placement of Synchrophasor Sensors for Risk Hedging in a Smart Grid

Modern power system with its numerous sophisticated technological integrant constituents and their intricate interconnections is materializing into a smart grid (SG). The phasor measurement units have become indispensable sensors for the real-time monitoring of the SG. In a typical SG, these sensors are deployed at several locations, on the electrical buses for the accurate measurement of time synchronized current and voltage phasors. The time tagged synchrophasor data are then communicated to the phasor data concentrator (PDC) through the synchrophasor sensor communication system (SSCS) for monitoring and control purposes. Risk analysis and the subsequent risk hedging of this system are quintessential to safeguard against cataclysmic botches pertaining to monitoring, control, and protection of the power system. The proposed research presents the framework for the risk assessment of the SSCS and the subsequent optimal placement of the synchrophasor sensors and their communication infrastructure for risk minimization. Another significant aspect of the proposed work is the use of microwave point-to-point links for the transfer of the data from the synchrophasor sensors to the PDC. Communication feasibility is assessed using the digital elevation model data, taking into account the line of sight and communication link availability constraints imposed by the microwave links. Simulation results for the practical power system of India validate the efficacy of the proposed work.

GENETIC ALGORITHM OPTIMIZED X-BAND ABSORBER USING METAMATERIALS

This paper presents a novel, Genetic Algorithm (GA) optimized X-band absorber using metamaterials. The unit cell of this structure consists of several square patches, each having a dimension of 2.5mm × 2.5 mm. Their positions are optimized using the GA such that the X-band absorption is maximized. Simulation results and the subsequent experimental validation affirm that the structure offers absorption of 97% from 10.42 GHz to 11.98 GHz and absorption of 90% over the entire X-band from 8GHz to 9GHz and also from 9.35 GHz to 12 GHz, with peak absorption of 99.95% at 10.52 GHz. The results are compared with the existing ones, to demonstrate the superiority of the proposed design.

Standards and Communication Systems in Smart Grid

The present-day power system is rapidly progressing in the fields of generation, transmission, and distribution of energy. Factors such as diverse and distributed nature of power consumption, increased use of the renewable energy that enables the consumer to also be an energy provider have exacerbated the complexity of the power grid. A glitch or a failure in one part of this complex network, unless espied and curtailed, can translate into a major power outage. This requirement has led to the inception of the smart grid. A smart grid consists of several intelligent sensors with advanced communication capabilities that collect, communicate, and monitor the real-time information pertaining to the grid dynamics. Apart from fault detection and outage prevention, there are several other applications of the smart grid such as electric substation automation, distributed energy resource management, automatic metering infrastructure (AMI), electrical vehicles (EVs), home automation. These applications require efficient communication technologies for transfer of information. This chapter presents a comprehensive description of the various smart grid communication systems and standards from the perspective of their application in smart grid. The future technologies and the challenges they pose are also discussed for the benefit of the research groups working on smart grid communications.

5G Communication Networks and Modulation Schemes for Next-Generation Smart Grids

Future wireless communication systems should have the ability to accommodate large number of mobile users increasing day by day. Moreover, various high-speed mobile applications such as online video streaming and online gaming, interconnection of different wireless devices for Internet of Things (IoT) are also some of the key requirements must be fulfilled. Hence, next-generation 5G wireless communication systems and smart grid (SG) communication systems requires high data rate, low latency, high spectral efficiency, low out-of-band (OOB) radiation, low power consumption, secure connectivity and ability to accommodate more number of users as well as diversified wireless devices distributed in large geographical regions for different mobile applications with maintaining uninterrupted connectivity at high speed. More sophisticated signaling schemes are required to overcome the limitations of orthogonal frequency-division multiplexing (OFDM), which is widely accepted by many researchers as one of the potential modulation schemes for 3.5G and 4G wireless standards. Even some of the multicarrier modulation schemes suitable for 5G applications, which work well at the frequency range of around 28 GHz, may not be suitable for millimeter wave (mmWave) frequency range of 60–90 GHz. Hence, in this chapter a comprehensive analysis of various types of potential waveforms such as generalized frequency-division multiplexing (GFDM), filter bank multicarrier (FBMC), universal filtered multicarrier (UFMC), and some of the extended version of OFDM, which can be used in 5G wireless communication systems. Some single-carrier modulation schemes suitable for mmWave are studied and discussed. Various issues for implementing these new waveforms and their advantages and disadvantages are also discussed. Smart grid (SG) communication technologies can be more reliable, secure and faster by using some of the modern signaling schemes. Finally, some of the standards of SG and its applications are discussed.

A Simple Multi-band Metamaterial Absorber with Combined Polarization Sensitive and Polarization Insensitive Characteristics for Terahertz Applications

This paper presents a simple multi-band metamaterial absorber for terahertz applications. The unit cell of the proposed structure consists of a single square ring having gaps at the centers on three of its sides. The proposed absorber produces three absorption bands for all polarizations and hence the design can be considered as insensitive to polarization variation. It provides an average absorption of 96.92% for the TE polarization with a peak absorption of 99.44% at 3.87xa0THz and for the TM polarization, it provides an average absorption of 98.4% with a peak absorption of 99.86% at 3.87xa0THz. An additional absorption peak is observed for the TE polarization at 1.055xa0THz that gradually diminishes with the increase in polarization angle and completely vanishes for the TM polarization. Thus, the structure displays a hybrid polarization response with polarization insensitivity in three bands and polarization sensitivity in one band. Parametric analysis has been carried out validating the optimal selection of the design parameters. The simplicity of the design and its combined polarization sensitive and polarization insensitive absorption characteristics can find tremendous applications in the field of terahertz imaging and sensing.

A Crossover Improved Genetic Algorithm and Its Application in Non-Uniform Linear Antenna Arrays

Genetic Algorithm (GA) is a widely used optimization technique with multitudinous applications. Improving the performance of the GA would further augment its functionality. This paper presents a Cr...

A multi band absorber using band gap structures

This paper proposes the design of a multiband absorber using EBG structures to absorb radiation in the X-band for stealth applications. It can also be used in the K and Ka bands for reduction of Electromagnetic Interference. The structure was created using Genetic Algorithm and the simulation was performed on Ansoft High Frequency Surface Solver (HFSS). The results indicate that the structure has 97% absorption in the X band at 8.2 GHz and absorbs most of the radiation in the K, Ka bands. The structure also has low RCS and hence can find use in military applications.

Realization of compact arrays with low side lobes using Biogeography Based Optimization

This paper presents a novel approach for synthesizing compact linear arrays with low side lobes for specified beam widths using Biogeography Based Optimization (BBO). BBO is applied to synthesize compact arrays with low side lobes for a given beam width and element spacing. The element spacing is based on minimal spacing criteria to avoid coupling between the elements. The simulation is performed for a 20 element array with different beam widths and spacing criteria. Results obtained are compared with other algorithms such as Modified Cuckoo Search (MCS) and Fire-fly algorithms (FA). especially in terms of size reduction and side lobe reduction.