Introduction - Utilities Industry

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SOUGATA MITRAUnit I: Reference Book

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TABLE OF CONTENTSElectric utility ................................................................................................................................................ 4

Current ..........................................................................................................................................................4

Voltage ..........................................................................................................................................................4

Electricity generation....................................................................................................................................4

Electricity transmission .................................................................................................................................4

Electricity distribution...................................................................................................................................4

thermal power station ..................................................................................................................................5

Hydroelectricity.............................................................................................................................................6

Nuclear power...............................................................................................................................................6

Wind power ..................................................................................................................................................6

Renewable energy ........................................................................................................................................6

Substation .....................................................................................................................................................7

Transmission substation ..................................................................................................................7

Distribution substation ....................................................................................................................7

Transformer ..................................................................................................................................... 7

Feeders.............................................................................................................................................7

Capacitors ........................................................................................................................................7

Load...............................................................................................................................................................8

Load Scheduling and Dispatch .........................................................................................................8

Load Balancing .................................................................................................................................8

Grid................................................................................................................................................................8

Distribution grid...............................................................................................................................8

Transmission Grid ............................................................................................................................8

Technical Loss ...............................................................................................................................................8

Commercial Loss ...........................................................................................................................................9

Transmission and Distribution Loss ..............................................................................................................9

Automation ...................................................................................................................................................9

Distribution management systems............................................................................................................... 9

High Voltage Distribution System (HVDS)..................................................................................................... 9

DEMAND RESPONSE ..................................................................................................................................... 9

Asset optimization ........................................................................................................................................9

Distributed generation:...............................................................................................................................10

Economic dispatch ......................................................................................................................................10

Monitoring and diagnostics ........................................................................................................................10


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Net metering...............................................................................................................................................10

Sensors........................................................................................................................................................10

SCADA .........................................................................................................................................................10

Human Machine Interface ..........................................................................................................................11

Remote Terminal Unit (RTU).......................................................................................................................11

Supervisory Station.....................................................................................................................................11

Smart Grid...................................................................................................................................................12

AMR.............................................................................................................................................................13

Advanced Metering Infrastructure .............................................................................................................13

Smart appliances.........................................................................................................................................13

Smart meters ..............................................................................................................................................13

Time of Day metering .................................................................................................................................13


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TERMINOLOGIES

ELECTRIC UTILITY Utility is a company (often a public utility) that engages in the generation, transmission, and distribution of electricity for sale generally in a regulated market. The electrical utility industry is a major provider of energy in most countries.

CURRENTCurrent is the flow of electrons in an electrical conductor, such as power lines or a power cord. The amount of movement of the electricity is measured in amperes.

VOLTAGEThe difference is electrical potential between any two points of an electrical circuit, expressed in volts.

Voltage is analogous to water pressure through a pipe.

ELECTRICITY GENERATIONIt is the process of creating electricity from other forms of energy. Electricity is most often generated at a power station by electromechanical generators, primarily driven by heat engines fueled by chemical combustion or nuclear fission but also by other means such as the kinetic energy of flowing water and wind.

ELECTRICITY TRANSMISSION Electric power transmission or "high voltage electric transmission" is the bulk transfer of electrical energy, from generating plants (historically hydroelectric, nuclear or coal fired but now also wind, solar, geothermal and other forms of renewable energy) to substations located near to population centers.

ELECTRICITY DISTRIBUTION Electricity distribution is the final stage in the delivery (before retail) of electricity to end users. A distribution system's network carries electricity from the transmission system and delivers it to consumers. Typically, the network would include medium-voltage (less than 33 kV) power lines, electrical substationsand pole-mounted transformers, low-voltage (less than 1 kV) distribution wiring and sometimes electricity meters.

THERMAL POWER STATIONIt is a power plant in which the prime movera steam turbine which either drives an propulsion. After it passes through the turbine, the where it was heated. The greatest variation in tdifferent fuel sources.

Typical diagram of a coal-fired thermal power station1. Cooling tower2. Cooling water pump3. transmission line (3-phase)4. Step-up transformer (3-phase)5. Electrical generator (3-phase)6. Low pressure steam turbine7. Condensate pump8. Surface condenser9. Intermediate pressure steam turbine

Unit I: Reference Book

prime mover is steam driven. Water is heated, turns into steam and spins which either drives an electrical generator or does some other work, like

. After it passes through the turbine, the steam is condensed in a condenserwhere it was heated. The greatest variation in the design of thermal power stations is due to the

fired thermal power station10. Steam Control valve 19. Superheater11. High pressure steam turbine 20. Forced draught (draft) 12. Deaerator 21. Reheater13. Feedwater heater 22. Combustion14. Coal conveyor 23. Economiser15. Coal hopper 24. Air preheater16. Coal pulverizer 25. Precipitator17. Boiler steam drum 26. Induced draught (draft)

18. Bottom ash hopper 27. Flue gas stack


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driven. Water is heated, turns into steam and spins or does some other work, like ship

condenser and recycled to he design of thermal power stations is due to the

Superheater20. Forced draught (draft) fan

air intake

Air preheater

26. Induced draught (draft) fan

stack


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HYDROELECTRICITY It is electricity generated by hydropower, i.e., the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy. Once a hydroelectric complex is constructed, the project produces no direct waste, and has a considerably lower output level of the greenhouse gas carbon dioxide (CO2) than fossil fuel powered energy plants.

NUCLEAR POWER It is power (generally electrical) produced from controlled (i.e., non-explosive) nuclear reactions. Commercial plants in use to date use nuclear fissionreactions. Electric utility reactors heat water to produce steam, which is then used to generate electricity.

WIND POWERIt is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, wind mills for mechanical power, wind pumps for pumping water or drainage, or sails to propel ships.

RENEWABLE ENERGY It is energy generated from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable (naturally replenished).

Biofuels are a wide range of fuels which are in some way derived from biomass. The term covers solid biomass, liquid fuels and various biogases.[1]

Biofuels are gaining increased public and scientific attention, driven by factors such as oil price spikes and the need for increased energy security.

Geothermal power is power extracted from heat stored in the earth. This geothermal energy originates from the original formation of the planet, from radioactive decay of minerals, and from solar energy absorbed at the surface.

Solar energy is power extracted from heat of the sun using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricityand biomass, account for most of the available renewable energy on earth. Only a minuscule fraction of the available solar energy is used.


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SUBSTATIONA substation is the meeting point between the transmission grid and the distribution feeder system. The transmission and sub-transmission systems above the substation level usually form a network. Typically, a substation consists of high and low voltage racks and buses for power flow, circuit breakers at the transmission and distribution level, metering equipment and the control house, where the relaying, measurement and control equipment is located.

TRANSMISSION SUBSTATIONA transmission substation connects two or more transmission lines. The simplest case is where all transmission lines have the same voltage. In such cases, the substation contains high-voltage switches that allow lines to be connected or isolated for fault clearance or maintenance. A transmission station may have transformers to convert between two transmission voltages, voltage control devices such as capacitors, reactors equipment such as phase shifting transformers to control power flow between two adjacent power systems.

DISTRIBUTION SUBSTATIONA distribution substation transfers power from the transmission system to the distribution system of an area. It is uneconomical to directly connect electricity consumers to the high-voltage main transmission network, unless they use large amounts of power, so the distribution station reduces voltage to a value suitable for local distribution.

TRANSFORMERA transformer is an electrical device that transfers power from one circuit to another without change in frequency. The purpose of a transformer is to convert one AC voltage to another AC voltage. A transformer comprises two or more coupled conducting coils (windings), which are wound on common laminated core of a magnetic material such as iron or iron-nickel alloy. These are called primary and secondary windings.

FEEDERSDistribution transformers, being connected to the consumers through radial feeders, which have only one path, have to be continuously energised for maintaining uninterrupted supply to consumers. Feeders route the power from the substation throughout the service area. They are typically either overhead distribution lines mounted on wooden poles, or underground buried or ducted cable sets. Feeders operate at the primary distribution voltage in primary distribution system and secondary distribution voltage in the secondary distribution system.

CAPACITORSCapacitor is a passive electronic component consisting of a pair of conductors separated by a dielectric. They can be used to store charge in an electrical circuit. A capacitor functions like a battery, but charges and discharges much more efficiently.


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LOADLoad is the amount of electric power delivered or required at any specific point on the system. The electric power required comes from the electricity-consuming equipment of the consumers.

LOAD SCHEDULING AND DISPATCHLoad scheduling means fixing the schedules of generation of power for generating stations and the schedules for drawl of power by the States taking into account drawl schedules from shared power sector projects and schedules of power purchased from buyers to sellers. Scheduling is done for the day ahead by the Regional Load Dispatch Centre to ensure balance between load and generation in the grid with the aim of achieving an operating grid frequency of 50 Hz.

LOAD BALANCINGLoad Balancing is the process of achieving and maintaining equal load on each phase of a distribution transformer. If load on each phase of the distribution transformer is not equal, it is called unbalanced loading of transformer.

GRIDThe grid is basically a connection of generating stations, substations and loads through transmission lines, at a voltage level above the distribution voltage.

DISTRIBUTION GRIDIt is the part of the electric grid that is dedicated to delivering electric energy to end-users. After traveling through transmission lines and distribution substations, electricity reaches the distribution grid, where distribution lines deliver electricity to industrial, commercial and residential electricity customers.

TRANSMISSION GRIDElectric power transmission is the bulk transfer of electrical power from a generation facility to a load or distribution substation center, which then distributes power to the end user.

TECHNICAL LOSSTechnical loss is inherent in electrical systems, as all electrical devices have some resistance and the flow of currents causes a power loss (I2R loss).Integration of this power loss over time, i.e. _ I2R.dt is the energy loss. Every element in a power system (a line or a transformer) offers resistance to power flow and, thus, consumes some energy while performing the duty expected of it. The cumulative energy consumed by all these elements is classified as “Technical Loss.”


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COMMERCIAL LOSSCommercial losses are caused by pilferage, theft, defective meters, and errors in meter reading and in estimating un-metered supply of energy.Some of the most occurred cause for Commercial Losses are:

Poor accuracy of measurement at consumer end Tampering of Meters Improper Energy Accounting System Billing Gap Collection inefficiency

TRANSMISSION AND DISTRIBUTION LOSSAT&C loss to the utility is the sum total of technical losses, commercial losses and loss due to non-realization of total billed units. AT&C loss for a year is also expressed as percentage of Energy Input. It is the difference between units injected into the system and the units for which the payment is collected. AT&C loss is a transparent measure of the overall efficiency of the distribution business as it measures technical as well as commercial losses.

AUTOMATIONAutomation is bringing “intelligence” to the grid, much as Internet technology has brought intelligence to computers. It allows for remote monitoring and control assets on the power grid.

DISTRIBUTION MANAGEMENT SYSTEMSA Distribution Management System (DMS) is a smart grid automation technology that provides real-time information about the distribution network and allows utilities to remotely control devices in the grid.

HIGH VOLTAGE DISTRIBUTION SYSTEM (HVDS)One of the latest innovations in efforts to reduce technical and commercial losses is the use of High Voltage Distribution System (HVDS) or LT-less system. In this system, the secondary distribution system with long LT feeders running up to consumer premises from the distribution substation is totally absent. The primary distribution system at HT level (11 or 33 kV) is used to reach the nearest point for a group of small number of consumers. The consumers are then connected to the HT Distribution System at these points through small pole mounted transformers used for supplying power to them through LT service lines.

DEMAND RESPONSEIn the electrical grid, demand response (DR) allows the management of customer consumption of electricity in response to supply conditions. For example, letting electricity customers opt into programs that reduce their consumption at critical times, or in response to market prices. Demand response is generally used to refer to mechanisms used to encourage consumers to reduce demand, thereby reducing the peak or overall demand for electricity.

ASSET OPTIMIZATIONAsset optimization refers to maximizing asset performance and reducing unexpected failures of primary

equipment (i.e. transformers) through alerts, detection, diagnosis, and prognosis. Asset-optimization technologies help maximizes asset performance and life for just a small fraction of what it would cost to replace them altogether.


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DISTRIBUTED GENERATION:Currently, most generation of electricity is centralized and electricity is sent one way – from utility to consumer. With a smart grid, the generation of electricity can be distributed – such as solar panels on rooftops. Energy can then enter the grid from many more locations.

ECONOMIC DISPATCHThis is a method of determining the most efficient, low-cost, and reliable operation of a power system by dispatching available electricity generation resources to supply demand. The primary objective is to minimize the cost of generation while honoring the constraints of the available generation resources.

MONITORING AND DIAGNOSTICSSmart grid monitoring and diagnostics technologies help utilities maximize asset performance and reduce unexpected failures of primary equipment (i.e. transformers) through alerts, detection, diagnosis, and prognosis. By monitoring different gas levels within the transformer, for example, smart sensors will detect and report potential problems back to the utility in real-time. The information sent to the utility can be stored and analyzed by advanced software, helping predict and prevent potential transformer failure before it happens.

NET METERINGUnder net metering, consumers who own renewable generation (such as solar on rooftops) can receive retail credit for at least a portion of the electricity they generate.

SENSORSSensors, in this case, refer to smart equipment placed at key locations on the power grid. They sense what is happening with the electric load or with the assets on the grid and communicate this status back to the utilities.

SCADA SCADA stands for supervisory control and data acquisition. It generally refers to an industrial control system: a computer system monitoring and controlling a process. The process can be industrial, infrastructure or facility-based as described below:

Industrial processes include those of manufacturing, production, power generation, fabrication, and refining, and may run in continuous, batch, repetitive, or discrete modes.

Infrastructure processes may be public or private, and include water treatment and distribution, wastewater collection and treatment, oil and gas pipelines, electrical power transmission and distribution, civil defense siren systems, and large communication systems.

Facility processes occur both in public facilities and private ones, including buildings, airports, ships, and space stations. They monitor and control HVAC, access, and energy consumption.


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HUMAN MACHINE INTERFACE

A Human-Machine Interface or HMI is the apparatus which presents process data to a human operator, and through which the human operator controls the process.

An HMI is usually linked to the SCADA system's databases and software programs, to provide trending, diagnostic data, and management information such as scheduled maintenance procedures, logistic information, detailed schematics for a particular sensor or machine, and expert-system troubleshooting guides.

The HMI system usually presents the information to the operating personnel graphically, in the form of a mimic diagram. This means that the operator can see a schematic representation of the plant being controlled.

REMOTE TERMINAL UNIT (RTU)

The RTU connects to physical equipment. Typically, an RTU converts the electrical signals from the equipment to digital values such as the open/closed status from a switch or a valve, or measurements such as pressure, flow, voltage or current. By converting and sending these electrical signals out to equipment the RTU can control equipment, such as opening or closing a switch or a valve, or setting the speed of a pump.

SUPERVISORY STATION

The term "Supervisory Station" refers to the servers and software responsible for communicating with the field equipment (RTUs, PLCs, etc), and then to the HMI software running on workstations in the control room, or elsewhere. In smaller SCADA systems, the master station may be composed of a single PC. In larger SCADA systems, the master station may include multiple servers, distributed software applications, and disaster recovery sites. To increase the integrity of the system the multiple servers will often be configured in a dual-redundant or hot-standby formation providing continuous control and monitoring in the event of a server failure.


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SMART GRIDThe smart grid marries information technology with our current electrical infrastructure, helping us support the energy needs of our 21st Century society. The smart grid is, in essence, an “energy Internet,” delivering real-time energy information and knowledge—empowering smarter energy choices.

A SmartGrid is an electricity network that can intelligently integrate the actions of all users connected to it - generators, consumers and those that do both – in order to efficiently deliver sustainable, economicand secure electricity supplies. A SmartGrid employs innovative products and services together with intelligent monitoring, control, communication, and self-healing technologies to:

Better facilitate the connection and operation of generators of all sizes and technologies; Allow consumers to play a part in optimizing the operation of the system; Provide consumers with greater information and choice of supply; Significantly reduce the environmental impact of the whole electricity supply system; Deliver enhanced levels of reliability and security of supply.

SmartGrids deployment must include not only technology, market and commercial considerations, environmental impact, regulatory framework, standardization usage, ICT (Information & Communication Technology) and migration strategy but also societal requirements and governmental edicts.


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AMRAMR is the technology of automatically collecting consumption, diagnostic, and status data from energy metering devices and transferring that data to a central database for billing, troubleshooting, and analyzing. This advance mainly saves utility providers the expense of periodic trips to each physical location to read a meter. Another advantage is billing can be based on near real time consumption rather than on estimates based on previous or predicted consumption. This timely information coupled with analysis, can help both utility providers and customers better control the use and production of electric energy, gas usage, or water consumption.AMR technologies include handheld, mobile and network technologies based on telephony platforms (wired and wireless), radio frequency (RF), or powerline transmission.

ADVANCED METERING INFRASTRUCTUREAMI refers to systems that measure, collect and analyse energy usage, and interact with advanced devices such as electricity meters, through various communication media either on request (on-demand) or on pre-defined schedules. This infrastructure includes hardware, software, communications, consumer energy displays and controllers, customer associated systems, meter data management(MDM) software, supplier and network distribution business systems, etc. The network between the measurement devices and business systems allows collection and distribution of information to customers, suppliers, utility companies and service providers. This enables these businesses to either participate in, or provide, demand response solutions, products and services. By providing information to customers, the system assists a change in energy usage from their normal consumption patterns, either in response to changes in price or as incentives designed to encourage lower energy usage use at times of peak-demand periods or higher wholesale prices or during periods of low operational systems reliability.

SMART APPLIANCESSmart appliances can be programmed to operate when it is most cost effective to do so based on time-of-use pricing signals from the utility. For example, a smart refrigerator would only enable the defrost cycle to occur when electricity prices are lowest, without compromising a consumer's lifestyle.

SMART METERSSmart meters are among the fundamental building blocks of smart grid deployments. They track and report energy usage by time of day, enabling utilities to charge less for electricity used during off-peak hours. As a result, consumers can choose to shift energy-intensive activities to times when rates are lower to save on energy costs.

TIME OF DAY METERINGTime of Day metering (TOD), also known as Time of Usage (TOU) or Seasonal Time of Day (SToD), metering involves dividing the day, month and year into tariff slots and with higher rates at peak load periods and low tariff rates at off-peak load periods. While this can be used to automatically control usage on the part of the customer (resulting in automatic load control), it is often simply the customers responsibility to control his own usage, or pay accordingly (voluntary load control). This also allows the utilities to plan their transmission infrastructure appropriately.

Unit I: Reference BookSOUGATA MITRA

Unit I: Reference Book

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Introduction - Utilities Industry