Distribution Sector considered as the weakest link in the entire power sector. It involves dealing with retail consumers with varied expectation and at the same time different paying capacity. It involves huge net work and requires net work management of vast area. Theft, pilferages, and network losses are also maximum in this segment. Since the metering, billing, and collection at many places involves human intervention and most of the times human error, intentional or non-intentional can occur. There is lack of infrastructure for data base management system, lack of employee ownership and internal resistance to change also observed in distribution sector. High level of technical and commercial losses and lack of commercial approach in management of utilities has led to unsustainable financial operations.
Inadequacy in transmission and distribution networks has been one of the major reasons for poor quality of supply. Resources of power generation are unevenly dispersed across the country. Electricity is a commodity that cannot be stored in the grid where demand and supply have to be continuously balanced. The widely distributed and rapidly increasing demand requirements of the country need to be met in an optimum manner. Supply of good quality of electricity at reasonable rate to consumer is essential for its overall development. Equally important is availability of reliable and quality power at competitive rates to Indian industry to make it globally competitive and to enable it to exploit the tremendous potential of employment
Today’s electric grid was designed to operate as a vertical structure consisting of generation, transmission, and distribution and supported with controls and devices to maintain reliability, stability, and efficiency. However, system operators are now facing new challenges including the penetration of renewable energy in the legacy system, rapid technological change, and different types of market players and end users. The smart grid is a self-healing network equipped with dynamic optimization techniques that use real-time measurements to minimize network losses, maintain voltage levels, increase reliability, and improve asset management.
The operational data collected by the smart grid and its sub-systems will allow system operators to rapidly identify the best strategy to secure against cyber attacks, vulnerability, and so on, caused by various contingencies. Additional features include facilities for the integration of renewable and obtaining information to and from renewable resources and plug – in hybrid vehicles. It is enabled to perform with robust and affordable real – time measurements and enhanced communication technology for data/information transmission. It allows smart appliances and facilitates the deployment of advanced storage technologies and control options, and supports DSM and demand response schemes. The Smart Grid is the transparent, seamless, and instantaneous two-way delivery of energy information, enabling the electricity industry to better manage energy delivery and transmission and empowering consumers to have more control over energy decisions.
Need of Smart Grid
The existing electricity grid is a product of rapid urbanization and infrastructure developments in various parts of the world in the past century. The growth of the electrical power system, however, has been influenced by economic, political, and geographic factors that are unique to each utility company. Despite such differences, the basic topology of the existing electrical power system has remained unchanged. Since its inception, the power industry has operated with clear demarcations between its generation, transmission, and distribution subsystems and thus, has shaped different levels of automation, evolution, and transformation in each step.
Given the fact that nearly 90 % of all power outages and disturbances have their roots in the distribution network, the move toward the Smart Grid has to start at the bottom of the chain, in the distribution system. Moreover, the rapid increase in the cost of fossil fuels, coupled with the inability of utility companies to expand their generation capacity in line with the rising demand for electricity, has accelerated the need to modernize the distribution network by introducing technologies that can help with demand-side management and revenue protection.
Characteristics of Smart Grid
A Smart Grid employs innovative products and services together with intelligent monitoring, control, communication, and self-healing technologies. The characteristics of smart grid are:
• Automatically detects and responds to problems. It greatly expanded data acquisition of grid parameters; focus on prevention, minimizing impact to consumers
• Digital communication networks permit the intelligent devices to communicate securely with the utility enterprise and possibly with each other.
• Data from the intelligent devices and many other sources are consolidated to support the transformation of raw data into useful information through advanced analytics.
• Business intelligence and optimization tools provide advanced decision support at both the automatic and human supervisory level.
• Smart Grid allows consumers to play a part in optimizing the operation of the system and provides consumers with greater information and choice of supply.
• It enables demand response and demand-side management through the integration of smart meters, smart appliances and consumer loads, micro-generation, and electricity storage and by providing customers with information related to energy use and prices. It is anticipated that customers will be provided with information and incentives to modify their consumption pattern to overcome some of the constraints in the power system.
• It accommodates and facilitates all renewable energy sources, distributed generation, residential micro-generation, and storage options, thus significantly reducing the environmental impact of the whole electricity supply system.
• It optimizes and efficiently operates assets by intelligent operation of the delivery system (rerouting power, working autonomously) and pursuing efficient asset management. This includes utilizing assets depending on what is needed and when it is needed.
• It operates resiliently in disasters, physical or cyber attacks and delivers enhanced levels of reliability and security of supplying energy. It assures and improves reliability and the security of supply by anticipating and responding in a self-healing manner, and strengthening the security of supply through enhanced transfer capabilities.
• It provides power quality of the electricity supply to accommodate sensitive equipment that enhances with the digital economy.
• It opens access to the markets through increased transmission paths, aggregated supply and demand response initiatives, and ancillary service provisions.
Finally, the smart grid will promote environmental quality by allowing customers to purchase cleaner, lower-carbon-emitting generation, promote a more even deployment of renewable energy sources, and allow access to more environmentally friendly central station generation. Furthermore, the Smart Grid will allow for more efficient consumer response to prices, which will reduce the need for additional fossil fuel-fired generation capacity, thereby, reducing the emission of CO2 and other pollutants.
Elements of Smart Grid: Transmission Subsystem
The transmission system that interconnects all major substation and load centers is the backbone of an integrated power system. Efficiency and reliability at an affordable cost continue to be the ultimate aims of transmission planners and operators. Transmission lines must tolerate dynamic changes in load and contingency without service disruptions.
Strategies to achieve smart grid performance at the transmission level include the design of analytical tools and advanced technology with intelligence for performance analysis such as dynamic optimal power flow, robust state estimation, real – time stability assessment, and reliability and market simulation tools. Smart transmission investment provides many benefits to power customers and electricity markets.
Real time monitoring instruments, state estimators sensors, and communication technologies are the transmission subsystem’s intelligent enabling tools for developing smart transmission network. Intelligent transmission systems include a smart intelligent network, self monitoring and self healing, the adaptability and predictability of generation and demand robust enough to handle congestion, instability, and reliability issues. This new resilient grid has to withstand shock (durability and reliability), and be reliable to provide real – time changes in its use. Two key issues in developing a super transmission grid involve citing decisions and providing reasonable policies for equitable cost allocation.
Intelligent Distribution System
The distribution system is the final stage in the transmission of power to end users. Primary feeders at this voltage level supply small industrial customers and secondary distribution feeders supply residential and commercial customers. At the distribution level, intelligent support schemes will have monitoring capabilities for automation using smart meters, communication links between consumers and utility control, energy management components, and AMI. The automation function will be equipped with self – learning capability, including modules for fault detection, voltage optimization and load transfer, automatic billing, restoration and feeder reconfiguration, and real
Demand side management options and energy efficiency options developed for effective means of modifying the consumer demand to cut operating expenses from expensive generators and defer capacity addition. DSM options provide reduced emissions in fuel production, lower costs, and contribute to reliability of generation. These options have an overall impact on the utility load curve. It is enabled to perform with robust and affordable real – time measurements and enhanced communication technology for data/information transmission. It allows smart appliances and facilitates the deployment of advanced storage technologies including plug – in electric vehicles and control options, and supports DSM and demand response schemes.
Monitoring and Control Technology
In a conventional power system, electricity is distributed from the power plants through the transmission and distribution networks to final consumers. Transmission and distribution networks are designed to deliver the electricity at the consumer side at a predefined voltage level. PV Solar power generation is in general connected at the distribution level of the power system. For this reason, it is possible for the power produced by the PV system to cause a ‘counter’ power flow from the consumer side to be delivered to other consumers through the distribution network. This phenomenon may present two challenges: an increase in the voltage in areas with high PV power generation and voltage fluctuation throughout the system due to the intermittency characteristics of the PV production.
Taking these issues into consideration, voltage control systems that incorporate optimal power flow computation software are developed. These systems have been designed to rapidly analyze power flow to forecast the voltage profile on the distribution network, and, in some cases, control voltage regulation equipment to ensure the appropriate voltage. The optimal control signal is developed through optimal power flow calculation.
Switchgear
In smart grid operation, automated switchgear operation is preferred over conventional operation. In conventional substations, all signals, controls and interlocks are hardwired and records are manually maintained in a logbook. Therefore, a lot of work and efforts is required to draw comparisons for analysis and trouble shooting. An automated substation, wherein all operations are automated, is more efficient and requires less manpower.
Traditionally, remote terminal units were used in substations as a link between the switchgear and the control centre. Some of these remote terminal units had intelligence features such as interlocking features, but no substation or region-wide automation was available. However, now more and more remote terminal units are being replaced by or complemented with specialized intelligent electrical devices that are capable of multiple protections and measurements in smart grid operation. In addition, intelligent gateways and concentrators have been introduced in the substation. In smart grid operations, monitoring and signaling are becoming an integral part of the switchgear, in addition to protection and control functions. Manufacturers are including intelligent built-in protection and control electronic devices in the switchgear to enhanced grid efficiency and reliability.
Smart Metering
A complete metering system is imperative for improving the financial health of the power distribution companies. A smart energy meter is typically electronic equipment that record and stored consumption data of energy in intervals of an hour, minute or less and communicates that information at least daily back to the utility for monitoring and billing purposes. Smart meters enable two-way communication between the meter and the central system. Unlike home energy monitors, smart meters can gather data for remote reporting. Automated meter reading systems in the distribution network read the consumption records, alarms, and status from customers’ premises remotely, thereby, reduces the human intervention.
Smart metering is essential for strengthening the power distribution segment. Efficient metering practices help to maintain the financial health of a utility. These include accurate billing and prevention of power theft, which have been the focus areas for utilities. These practices also help in lowering aggregate technical and commercial losses of the utilities. Transition from electromechanical meters to electrostatic meters was one of the first step towards improving consumer metering and minimize the human intervention. Now, the utilities are adopting smart metering, prepaid metering, net metering etc and focusing in meter data analysis.
Storage Component
Due to the variability of renewable energy and the disjoint between peak availability and peak consumption, it is important to find ways to store the generated energy for later use. Options for energy storage technologies include pumped hydro, advance batteries, flow batteries, compressed air, super – conducting magnetic energy storage, super – capacitors, and flywheels. Associated market mechanisms for handling renewable energy resources, distributed generation, environmental impact and pollution are other components necessary at the generation level. For handling renewable energy resources, distributed generation, environmental impact and pollution has to be introduced in the design of smart grid component at the generation level.
Key Challenges
• Ensuring that there is sufficient transmission capacity to interconnect energy resources, specially renewable resources.
• Developing the most efficient connections for offshore wind farms, floating solar and for other marine technologies.
• Enabling smaller-scale electricity supply systems to operate harmoniously with the system.
• Delivering the communications infrastructure to allow potentially millions of parties to operate and trade in the single market.
• Enabling all consumers, with or without their own generation, to play an active role in the operation of the system.
• Finding the best ways of integrating intermittent generation including residential micro-generation.
• Capturing the benefits of distributed generation and storage.
• Financial viability and cost benefit analysis of development of smart grid.
• Regulatory issues and approval of capital expenditure to pass on the consumers.
• Smart Grids must accommodate the needs of all consumers, electrical vehicles are particularly emphasized due to their mobile and highly dispersed character and possible massive deployment in future, which would yield a major challenge
Way forward
The overall distribution system has been highly inefficient, as is visible by the customers continue sufferings. Although economic growth in India in the last few years has been impressive, it is recognized that with expansion of its electrical grid, country loses money for every unit of electricity sold due to its weak infrastructure. With a view to empowering India to continue its path of economic growth, it needs to develop an intelligent and efficient grid. Only a reliable and financially secure smart grid can create a conductive environment for investment in electric infrastructure.
Large scale implementation of smart grid projects are expected to address some of the significant challenges such as weak infrastructure, power thefts, transmission and distribution losses, and higher quality of power, with reducing frequency of blackouts. As a bonus, smart grid implementation is expected to introduce a fresh pool of talents, skills, and knowledge. However, serious challenges in adopting smart grid, such as theft of electric power, perhaps unthinkable in the developed world and need to be handled.
The distribution sector in India is in shambles with shoddy implementation and total mismanagement. Regulatory controls are either absent or too weak to be felt or seen for its effects. Forum of Regulators have issued a model regulation for smart grid. Some of the state regulators also issued regulation for implementation of smart grid in the respective state. A smart grid has therefore, been identified among the most important solutions to meet the increasing demand for power and to ensure better energy efficiency.
In order to boost the systematic growth of the smart grid in the country, India Smart Grid Forum, India Smart Grid Task Force, and National Smart Grid Mission have been active under the aegis of the Ministry of Power. The India Smart Grid Task Force is an inter-ministerial group serves as the government focal point for activities related to smart grid and to evolve a road map for implementation of smart grids in India. Besides, National Smart Grid Mission has been spearheading a number of pilot projects on smart grid implementation.
Conclusion
Much work has been undertaken in the areas of policy and standards, framework development, and the assessment of new, intelligent tools to achieve the objectives of the smart grid. With the financial support of utilities and government agencies, the work is primarily directed to the preparation of the smart grid environment, particularly in terms of retrofitting and increasing the efficiency and reliability of the grid. Ultimately, smart grid reduces aggregate technical and commercial losses and ensures quality power to the consumers at reasonable manner.
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