Smart grid

Todays electric grid was designed to operate as a vertical structure consisting of generation, trans and dist.Supported with controls and devices to maintain reliability ,stability and efficiencyNow operators facing challenges including the penetration of RER , rapid technological changes and different types of market players and end users

SMART GRIDThe next iteration smart grid will be equipped with communication support schemes on real time measurement techniques to enhance resiliency and forecasting.Protection against internal and external threats.Framework: based on unbundling and restructuring the power sector and optimizing its assetsSmart gridNew grid: capable of Handling uncertainties in schedules and power transfers across regions

Accommodating renewables Optimizing the transfer capacity of transmission and distribution networks and meeting the demand for increased quality and reliable supply

Managing and resolving unpredictable events and uncertainties in operations and planningcapabalityCharacteristics Todays grid Smart gridActive consumer participationConsumers are uninformed and do not participateInformed, involved consumers; demand response and distributed energy resourcesAccommodation of all generation and storage optionDominated by central generation; many obstacles exists for distributed energy resources interconnectionMany distributed energy resources with plug and play- focus on renewablesNew products services and marketsLimited , poorly integrated wholesale markets: limited opportunities for consumers Mature, well integrated wholesale markets. Growth of new electricity markets for consumersProvision of power quality for digital economyFocus on outages- slow response to power quality issues Power quality a priority with a variety of quality/price optionsAnticipating responses to system disturbances (self healing)Response to prevent further damage: focus on protecting assets Automatically detects and responds to problems : focus on prevention , minimizing impact to consumersComparison of todays grid with smart grid4There are many smart grid definitions, some functional, some technological, and some benefits-oriented. A common element to most definitions is the application of digital processing and communications to the power grid, making data flow and information management central to the smart grid.

DEFINITIONA smart grid is a modernized electrical grid that uses information and communications technology to gather and act on information, such as information about the behaviors of suppliers and consumers, in an automated fashion to improve the efficiency, reliability, economics, and sustainability of the production and distribution of electricitydefinitionAdvanced metering infrastructureOutage management systemPower quality management Demand responseRenewable integration microgridSmart home energy managementEnergy storageElectric vehicleSmartgrid attributesfacilitates monitoring and measurement of consumer information through Smart Meters installed at customer premises. The information is transferred to utility control centre through communication mode such GPRS / PLC / RF. Smart meters will also enable Time of Day (TOD) and Critical Peak pricing (CPP)/Real Time Pricing (RTP) rate metering and monitoring based on energy consumption.Advanced Metering Infrastructure (AMI)Recording energy consumption data for consumer and utility (kWh, kVARh voltage, pf, max demand etc.)Automatically send the consumption data to the utility at pre-defined intervals. Time-based pricing signal for Demand Response.Bi-directional communication ability. Net metering to facilitate integration of Distributed Generation in the form of Roof Top Solar etc. Loss of power (and restoration) event notification. Remote Load limiting for Peak Load management. Remote connection and disconnection of individual supply. Energy prepayment. Reporting meter tampering in real time to the utility. Communications with other intelligent devices in the home. Gateway to communicate other meters data (Gas/water).

Main features of AMI are:

OMS manages unscheduled and scheduled outages of distribution infrastructure like Distribution Transformers (DTs), HT/LT feeders etc. It collect and coordinates information about outages including customer calls and report the operator for taking corrective actions through crew management and remote control enabling customer satisfaction, improve System Availability and Reliability. Outage management systemPower Quality Management address events like Voltage flickering (Sags/Swells), unbalanced phases voltages and harmonic distorted/contaminated supply etc. This will facilitate efficient and reliable operation of the power system, reduce losses, improve customer satisfaction and reduced equipment (utility/consumer) failures. Power Quality management shall include voltage / VAR Control, Load balancing, Harmonics Controller etc.

Power quality managementThe DR application collects information from various systems like the load forecast, SCADA, and MDM sub systems. Based on these inputs power demand-supply is determined for present and the next time block and the deficit/surplus is worked out. Based on the deficit/surplus demand response signals are sent out to the consumers.

Demand responseDemand Side Management solution helps to make the electric grid much more efficient and balanced by assisting the consumers reduce their overall electric demand, and/or shifts the time period when they use their electricity, and/or prioritizes the way they use electricity, and in so doing, reduces their overall energy costs. It also helps utility in deferring additional investment in capacity addition, reductions of AT&C losses.DSMDemand response (DR) mechanism shall create an understanding among consumers that pricing of electricity varies significantly during the day, facilitating consumer for wiser use of electricity. Demand response includes turning off non essential loads & shifting energy intensive activities to off peak hours.DRA Microgrid is an integrated energy and communication system consisting of interconnected loads and Distributed Energy Resources (DER) which mainly operates in standalone mode or in parallel with the grid (macro grid) in case of emergency. Microgrid generation resources include Micro turbines, wind, solar, fuel cells or other energy sources. The multiple dispersed generation sources and ability to isolate the microgrid from a larger network provides highly reliable electric power to its consumers. MicrogridThe Home Energy Management System will enable the end user to monitor energy consumption & cost of electricity, optimise energy usage, control appliances and other devices, make informed decisions under variable pricing structure, participate in demand response programs empowering consumer involvement in energy management process. Smart home energy managementGrowing Electrical power needs for the space craft systems-Megawatt rangeExisting DC based power systems has limitations excessive copper cable weight to compensate for the lossesEarly AC power distribution employees solar arrays and brayton generator has power sourcesRotary transformer and series resonant inverter to generate high frequency power

High Frequency in Space ApplicationCapgeminis Vision:Capgemini believes that in order to make meaningful progress toward addressing the current grid challenges and delivering on the future grid characteristics, utilities should focus on four main activities:1.Gather data: Data should be collected from many sources on the grid.

2. Analysis/forecasting: The data that is gathered should be ana-lyzedfor operational and business purposes.

3. Monitor/manage/act: In the operational world, data that comes from the grid hardware will trigger a predefined process that will inform, log or take action.

4. Rebuilding the grid to support bi-directional power flow andtransfer of power from substation to substation: This is to enablethe information that is collected and analyzed to be acted on.IBM believes that the smart grid will be manifested by a steady progression toward a Participatory Network, a technology ecosystem comprising a wide variety of intelligent network-connected devices, distributed generation, and consumer energy management toolsIBMs Vision (www.ibm.com/iibv)Preparing for an environment in which customers are more activeparticipants.

Capitalizing on new sources of real-time customer and operational information, and deciding which role(s) to play in the industrys evolving value chain.

Better understanding and serving an increasingly heterogeneouscustomer base.To make these improvements, IBM believes that utilities will de- ploy advanced energy technologies such as smart metering, sensors and distributed generation.

They believe that these technologies respond to the following interests:

IBMThe combination of energy price increases and consumers in- creased sense of responsibility for the impact of their energy usage on the environment.

The frequency and extent of blackouts are driving consumers, poli- ticians and regulators alike to demand assessment and upgrade of the industrys aging network infrastructure.

Climate change concerns have invigorated research and capacity investments in small, clean generating technologies.

Technology costs have generally decreased as lower-cost commu- nications, more cost-effective computing and open standards have become more prevalent.IBMFor utility executivesGE believes the potential for dramatic energy productivity gains could improve service, control costs and strengthen reliability.

For operations managersGE anticipates a reduction in the frequency and impact of outages with improved real-time knowledge of grid status.

For chief information technology officersGE sees the smart gridas based on open-standard software and communication protocols, easing systems integration and support.

General Electric Vision (www.gepower.com)For maintenance and engineering professionals- GE believes morecan be done with less, and focuses resources on improving service,instead of simply maintaining it.

Accurate, real-time and actionable knowledge of grid status enables a shift from time-based to need-based maintenance. It also allows for a more timely response to outages, speeding power restoration.

For customer service (call center) functionsCalls can be anticipat-ed when an outage has occurred, making systems more responsiveto customers. Armed with answers, calls can be resolved faster,allowing delivery of accurate information and a reduction of call-backs, queue times and staffing levels.

GESome major elements GE believes will be included are:

Distributed generation working seamlessly with current assets.

Smart homes that make savings practical and ease facets of every-day life.

Demand response that really knows demand and optimizes response.GEThermal issues are generally related to thermal limits caused, change in the network configuration. In a meshed power system, there can occur a situation where a low impedance line carries much more power than originally designed for, while parallel paths are underutilized.

In the future when, among others, private companies will operate transmission lines and sell energy to interested parties, the load flow will have to be controlled. One possibility is to use HVDC lines; another possibility is load flow control using FACTS devices in an AC network;

Voltage and reactive power control issueslow voltage at heavily loaded transmission lines as well high voltage at lightly loaded lines are undesirable occurrences in transmission lines.

The first can be a limiting factor responsible for reduced value of the transmitted power and the second can cause equipment damage.

The corrective actions with utilization of selected FACTS devices include correcting the power factor and compensating reactive losses in lines by supplying reactive power;Power Flow Control Loss reductiongenerally, total losses in a system cannot be reduced to such an extent that the installation of power flow controllers is justified.Only the losses due to reactive power flow, which usually are quite small, are easily avoidable. A reduction of the losses due to active power flow would require a decrease of the line resistances. However, loss reduction in a particular area of the system is a relevant issue. Power flow controlPower transfers from one point to another will physically flow on a number of parallel paths and thereby impel losses on lines that might belong to another utility, thus causing increased costs for that company. If the latter utility cannot accept these losses, power flow control can be a solution;Transient and dynamic stability control issuestransient stability describes the ability of the power system to survive after a major disturbance, while dynamic stability describes sustained or growing power swing oscillations between generators or a group of generators initiated by a disturbance (fault,major load changes etcPower flow controlThe first phenomenon can be improved by synchronizing power flow between sending and receiving ends. A solution for the second phenomenon lies in the use of equipment that permits dynamic damping of such oscillations. In the first as well as the second situation, active power flow control can be a solution.

Power flow controlDelivery of power at multi kHz frequency via electric cables Flexibility to meet loads at different voltage levelsEase of electrical isolation using compact high freq transformersSavings in component and system integrationImproves the dynamic response of the systemReduces acoustic noiseDevelopment in high frequency cable and magnetic materials ,resonant power converter technologiesAdvanced Soft Switching schemes

High frequency AC power distribution platforms High frequency operation higher EMI and higher cross talkDesign of power cables that carry high frequency current without significant skin and proximity effect lossesCable must also have low inductive reactance to minimize voltage drop and radiated magnetic fields

HFAC system for space application proposed by Sood and Lipo Pulse density modulation called area comparison pulse density modulation to control the amplitude of the power outputThis refers to minimization of volt time area, difference between the reference signal and the synthesized output signalThe circuit aims to produce the correct proportion of positive and negative half cycle pulsesPower conversion systemHigh brid or double tuned resonant inverter was developed.Aims to meet the steady state operating requirement of a power source for the international space station mobile servicing systemThe key requirements are high efficiency at varying load, good voltage regulation and low harmonic distortion

HVAC for low power applicationPresent power distribution DC domainHigher power requirements - Higher complexity higher reliability compactness challenges for DC distributionsTwo types of power distribution centralized DC / DC and distributed DC/DCThe first method simple to implement for a single DC/DC converter, converting 48 Volts battery input to different voltagesThe current to be distributed in bus bar is very high

High frequency in Telecommunication Results in larger conductors - Excessive heat voltage drop