INTRODUCTION TO SMART GRID (KOE084)
B.Tech – Semester VIII | Theory Examination (2024–25)
SECTION A
(Attempt all questions – brief but descriptive)
a) Functions of Smart Grid
A smart grid performs several important functions to improve the efficiency and reliability of the power system. It enables real-time monitoring of power generation, transmission, and distribution, supports two-way communication between utilities and consumers, integrates renewable energy sources, improves fault detection and self-healing capabilities, and enhances demand-side management. These functions collectively make the power system more intelligent, flexible, and resilient.
b) Need of Smart Grid
The need for a smart grid arises due to increasing electricity demand, integration of renewable energy sources, aging power infrastructure, and the requirement for improved reliability and efficiency. Conventional power grids lack real-time monitoring and control, leading to higher losses and frequent outages. Smart grids address these issues by enabling automation, better load management, and improved power quality.
c) Outage Management System
An outage management system is a software-based system used by utilities to identify, analyze, and restore power outages efficiently. It uses data from smart meters, sensors, and customer reports to detect fault locations, estimate restoration time, and optimize repair operations. This system significantly reduces outage duration and improves customer satisfaction.
d) Conventional Sensors and Smart Sensors
Conventional sensors only measure physical quantities such as voltage or current and transmit raw data, whereas smart sensors have embedded processing and communication capabilities. Smart sensors can analyze data locally, communicate with control systems, and support automated decision-making, making them more suitable for smart grid applications.
e) Phasor Measurement Unit (PMU)
A Phasor Measurement Unit is a device used in smart grids to measure electrical waves on the power system in real time. PMUs provide synchronized measurements of voltage, current, frequency, and phase angle using GPS signals. These measurements help in monitoring grid stability and detecting disturbances quickly.
f) Intelligent Electronic Devices
Intelligent Electronic Devices are microprocessor-based devices used in power systems for protection, control, and monitoring. Examples include digital relays and smart meters. These devices enhance automation and improve reliability in smart grid environments.
g) Microturbine
A microturbine is a small-scale power generation unit that converts fuel energy into electrical energy using a gas turbine. It is commonly used in distributed generation systems due to its compact size, high efficiency, low emissions, and ability to operate on various fuels.
h) Need and Benefits of Microgrid
A microgrid is a localized group of loads and distributed energy resources that can operate independently or in coordination with the main grid. The need for microgrids arises from the requirement for reliable power supply, especially in remote or critical areas. Microgrids improve energy efficiency, enhance reliability, support renewable integration, and reduce transmission losses.
i) Harmonics
Harmonics are voltage or current components that occur at integer multiples of the fundamental frequency. They are mainly caused by nonlinear loads such as power electronic devices. Harmonics degrade power quality and can cause overheating, equipment malfunction, and increased losses.
j) Power Quality Conditioner
A power quality conditioner is a device used to improve power quality by mitigating issues such as voltage sags, harmonics, and flicker. It ensures stable and reliable power supply to sensitive loads in smart grid systems.
SECTION B
(Attempt any three – long descriptive answers)
a) Opportunities and Barriers of Smart Grid
The smart grid offers several opportunities such as improved energy efficiency, enhanced reliability, integration of renewable energy sources, reduction in transmission losses, and better consumer participation. However, barriers such as high initial investment, cybersecurity risks, lack of skilled manpower, regulatory challenges, and interoperability issues slow down smart grid implementation.
b) Automatic Meter Reading and Conventional Metering
Automatic Meter Reading is a technology that enables remote collection of energy consumption data from smart meters without manual intervention. Unlike conventional metering, which requires physical meter reading, AMR provides real-time data, improves billing accuracy, reduces human errors, and supports demand response programs.
c) Geographic Information System and Its Role in Smart Grid
A Geographic Information System is a computer-based system used to capture, store, analyze, and display geographically referenced data. In smart grids, GIS helps in asset management, outage analysis, planning of distribution networks, and efficient maintenance by providing spatial visualization of power system components.
d) Formation and Impact of Microgrid
A microgrid is formed by integrating distributed energy resources such as solar panels, wind turbines, energy storage systems, and loads within a defined boundary. The impact of microgrids on conventional grids includes reduced load on transmission systems, improved reliability, and enhanced renewable penetration, though it also introduces challenges related to protection coordination and control.
e) Web-Based Power Quality Monitoring
Web-based power quality monitoring systems allow real-time observation of power quality parameters through internet-enabled platforms. These systems enable utilities and consumers to access data remotely, analyze disturbances, and take corrective actions quickly, improving overall grid performance.
SECTION C
Working of Resilient and Self-Healing Smart Grid
A resilient smart grid is designed to withstand disturbances such as natural disasters and cyberattacks, while a self-healing smart grid automatically detects faults and restores power supply with minimal human intervention. These capabilities are achieved using advanced sensors, communication networks, and automated control systems.
CDM Opportunities and Carbon Credit Enhancement
Clean Development Mechanism opportunities allow countries to earn carbon credits by implementing projects that reduce greenhouse gas emissions. Smart grids support renewable energy integration and energy efficiency, contributing to emission reduction and enhancing a country’s carbon credit potential.
Plug-in Hybrid Electric Vehicles
Plug-in Hybrid Electric Vehicles use both an internal combustion engine and an electric motor powered by rechargeable batteries. In a smart grid environment, PHEVs support reduced fuel consumption, lower emissions, and improved grid flexibility through controlled charging.
Vehicle-to-Grid Technology
Vehicle-to-grid technology allows electric vehicles to supply stored energy back to the grid during peak demand periods. This technology improves grid stability, supports renewable integration, and provides economic benefits to vehicle owners.
Compressed Air Energy Storage
Compressed Air Energy Storage stores excess electrical energy by compressing air and storing it in underground caverns. During peak demand, the compressed air is released to generate electricity. CAES supports grid stability and large-scale energy storage in smart grids.
Feeder Automation and Substation Automation
Feeder automation involves automatic monitoring and control of distribution feeders to improve reliability, while substation automation integrates protection, control, and communication systems within substations. Both play a vital role in enhancing smart grid efficiency.
Types of Solar Cells and Applications
Solar cells are classified into crystalline silicon, thin-film, and emerging technologies such as perovskite cells. These cells are used in residential rooftops, solar power plants, and off-grid applications, contributing to clean energy generation.
Limitations of Microgrid and Distributed Energy Resources
Microgrids and distributed energy resources face limitations such as high initial costs, complex control requirements, protection coordination challenges, and regulatory issues. Addressing these limitations is essential for wider adoption.
Role of Power Quality Monitoring in Smart Grid
Power quality monitoring helps identify disturbances such as harmonics, voltage sags, and flicker. Continuous monitoring enables timely corrective actions, ensuring reliable and high-quality power supply in smart grids.
Power Quality Issues of Solar Integration
Integrating solar power plants introduces power quality issues such as voltage fluctuations, harmonics, and intermittency. Smart grid technologies help mitigate these issues through advanced control and energy storage systems.
