Towards a Smarter and Greener Grid

Smart grid is an energy distribution network that can monitor energy flow and adjust itself to

changing conditions. This is achieved by controlling the connected demand and generation. The

distribution networks are required to be actively managed on real time along with the consumers

they serve, to cope with rapidly changing demands on the network. Smart grid continuously

monitors the network, predict failures and thereby reducing maintenance costs.

One of the prime advantages of Smart Grid is the reduced dependency on traditional carbon

based energy resources and shifting to low carbon resources.

Basic features of Smart Grid includes:-

Smart Metering with two way communication system facilitates-

A. End user participation

B. Increased Control

C. Enhanced Coordination and Integration

D. Peak Load Management (PLM) including Demand Side Management & Demand Response

E. Outage Management System (OMS)

F. Renewable Energy integration with Net Metering

G. Power Quality Management (PQM)

H. Micro Grid

I. Energy Storage system J. Electric charging vehicle

Smart Grid Building Blocks

Smart grids utilises metering, communications and control over the entire distribution system to

optimize the supply of electricity and integrate distributed energy sources.

It comprises:

A) Smart Meters (AMI):

Fig: Typical AMI meter

Advanced metering infrastructure (AMI) applies a communications system and solid state meters

capable of remotely providing each customer’s electricity use detail to the utility at 15 minute or

hourly intervals. Additional information including peak electricity use, voltage and other power

characteristics are also available. A variety of communications options can be used to transmit

Smart

AMI

Meter

data from individual meters back to utility operations. A few of these options include public

WiFi, private radio systems, and power line carrier systems that transmit information through the

electric distribution system. Smart meters can also provide radio gateways into premises to

control and develop information for individual appliances.

It can drastically reduce overhead charges on account of meter reading, customer services, field

services, collections, theft management and other functions. The utility can connect/

disconnect the meters with or without prior warning messages.

B) Power Quality Management

Fig: Capacitive filters & Active filters

• Improving the voltage profile is one of the main advantages of having power quality

management systems installed at distribution side. It includes systems like capacitor

banks, voltage regulators, and transformers that are used to control power flows.

Existing equipment can often be retrofitted by adding communications and control

capabilities. The ability to get information at the utility control room from these devices

and to remotely control their functions provides utilities with an opportunity to

significantly improve utility operations.

• For example it can automatically isolate faulty sections of the grid and reroute the power

to minimize the number of customers impacted. It can also identify the fault location and

take necessary action to correct the problem.

• Similarly, it can monitor the distribution transformer load and take suitable action to

divert the load and prevent the failure of transformers. Transformer monitoring devices

can continuously monitor fault gases to identify internal faults of transformer and prevent

the failure of transformers.

• Smart grid metering and control capabilities also provide significantly improved voltage

control on feeders compared to traditional power system practices. Utility engineers

design substations, transformers and distribution circuits including voltage regulators and

capacitor banks and other equipment accordingly. Since voltage drops with distance

from the substation, voltage levels at the substation must be higher than the voltage

required at the end of the feeders.

• Voltage drops depend on loading along the feeder and other related factors. Voltage

regulators and capacitor banks are used to improve voltage profile along the feeder and to

reduce the adverse effect of reactive power. However, since little information is

typically available end user side voltage, most systems fail on the side of providing higher

voltage than required, often by a higher percent, to ensure sufficient voltage at user end.

This practice wastes power, increases line losses, increases maintenance costs and

increases overall costs to customers.

• Expanded smart grid customer and distribution system metering dramatically increases

opportunities to optimize the distribution system. Smart meters can typically provide

15-minute and on-call information on voltage and reactive power providing visibility into

voltage at nearly every point along individual feeders. Increased metering and

controllers on feeders can provide near real-time information and alerts utility operators

when contingency arises. This information can be applied with software optimization

techniques to minimize energy use, peak demand and distribution system losses while

ensuring minimum acceptable voltage to individual.

• PQM put a brake on voltage fluctuations, unbalanced phases voltages and harmonic

distortions of utility supply. This will facilitate efficient and reliable operation of the

power system, reduce losses, improve customer satisfaction and reduced equipment

failures. Power Quality management shall include voltage / reactive power control, Load

balancing, Harmonics Controller etc.

• Power quality determines the fitness of electric power to consumer devices.

Synchronization of the voltage frequency and phase allows electrical systems to function

in their intended manner without significant loss of performance. Without quality power,

the end user equipment may malfunction, fail prematurely or may not operate at all.

Several factors contribute to the poor quality of electric power.

Power quality conditioners are intended to improve the quality of power so that

• Efficient power transfers between utility grid and micro grid.

• Isolate utility grid and micro grid from noises and other disturbances.

• Integration with energy storage system.

The following are some of the components of power quality conditioners.

• Distribution static compensators.

• Active power filters

• Automatic power factor correctors

C) Communications systems:

Fig: Various communication technologies

• In addition to providing communications from smart meters to the utility operations

center, the smart grid must deliver information from all intelligent electronic devices

(IEDs) throughout the distribution system including substation, distribution transformer

and feeder status data. These information channels can be established using various

communication technologies.

• Utilities use the SCADA (supervisory control and data acquisition) for communications

and control of basic equipment in the distribution system. SCADA system can often be

expanded to handle additional smart grid information and functions and /or additional

communications and control systems

• Different smart grid technologies and applications have different bandwidth requirements

and accordingly smart grid communications development requires meticulous planning of

backbone communication needs.

D) End user participation

Fig: End user interaction with Smart Grid

• An AMI/smart metering and communications system can provide routine 15-minute or

hourly customer electricity use data as well as information on an on-call basis not only

from the customer meter to the utility but from the utility back to the customer.

Information provided to the customer, typically through an internet portal, usually

includes 15 minute or hourly electricity use along with information on current month

usage and expenditures, estimates of the total monthly bill, and in some cases,

information on electricity use of similar customers in the neighbourhood.

• The ability of smart grids to engage customers to reduce electricity use at peak periods is

a primary benefit of smart grid investments. Utilities that pay $10/kW or even $20/kW

for peak power but charge their customers’ rates that are averaged over a month or over

several time periods in the day, can reduce power purchase or production costs by

significantly more than revenue losses when they encourage customers to reduce peak

electricity use.

E) Peak Load Management (PLM) including Demand Side Management & Demand

Response

• Load management, also known as demand side management (DSM), is the process

of balancing the supply of power on the network with the load by controlling the load

rather than the power being generated. This can be achieved by direct intervention of the

utility in real time or by using special tariffs to influence consumer behaviour. Load

management allows utilities to reduce demand for electricity during peak usage times,

which can, in turn, reduce costs by eliminating the need for peaking power plants.

• Managing peak load will be key driver as energy cannot be stored for longer duration in

large scale. The alternative option is reducing demand through demand -side management

and variable pricing for peak and off-peak hours, which can be achieved only through

Smart Grid. With Smart Grid, the critical loads of households can be met in the event of

power shortage, whereas important, institutions like Hospitals, Government offices etc

can be fed with un-interrupted power supply. Such dynamic and judicious control of

power supply will provide win-win situation for everybody and help avoid power outages.

F) Outage Management System (OMS)

Fig: Typical outage management system

• Manages outages of distribution infrastructure like Distribution Transformers, LT feeders

etc. It collects and coordinates information about outages including customer calls and

initiates corrective actions and thereby ensuring customer satisfaction, improve System

Availability and Reliability. It not only alerts the utility to an outage but also reports the

exact location of fault and thereby minimizing the effect of an outage by rerouting and

restoring power to as many customers as possible quickly. FPI (fault passage indicators)

are installed to receive the alerts at utility control centre. The outage information will be

analysed by operator concerned who in turn can evaluate possible switching sequences

such that power may be restored at the earliest.

DT monitoring systems are installed to monitor

• Oil temperature

• Oil level

• Winding temperature

• Total harmonic distribution

G) Renewable Energy integration with Net Metering

Fig: typical net metering system

• Net metering is a service to an electric consumer under which electric energy generated

by that electric consumer from an eligible on-site generating facility and delivered to the

local distribution facilities. It allows customers to install a Renewable Energy (RE)

facility so they can generate electricity for their own use. Any excess power generated by

the customer is automatically exported to the DU’s grid.

• The Net Energy Metering (NEM) Program is for customers with their own generation. If

customer produces more energy than he use, he can earn bill credits for the excess power

he has injected into electric grid. Further he can later use that credit to cover the power

he may require from Utility Grid.

H) Micro Grid

Fig: Micro grid

• A micro grid is a localized linkage of power generation, energy storage and loads

connected to a utility grid (macro grid). The micro grid can function autonomously

too. Power generation and load points in a micro grid are usually interconnected at

low voltage. The advantage is that a connected micro grid can be controlled by utility

as if it were one entity. Excess power generated by the micro grid can be injected into

the utility grid. The size of micro grid can vary from small townships to bigger

localities.

• Micro grid generation include fuel cells, wind, solar, or other energy sources with its

biggest ability is to isolate itself from a larger network and continue providing highly

reliable electric power. In addition, the produced heat from generation sources such as

micro turbines could be used for local process heating or space heating, allowing

flexible trade-off between the needs for heat and electric power.

Why micro grid?

• Transmission losses get reduced drastically.

• Substantial monetary savings

• Substantial cut in emissions

• Prevent the failure of utility grid by reducing the load on the grid.

• Instant isolation from the utility grid without affecting any loads, during a utility grid

disturbance.

I) Energy Storage system

Fig: typical energy storage systems

• Energy storage is a method used to store electricity on a large scale within an electrical

power grid. Electrical energy is stored when production exceeds consumption and when

additional load is turned on but consumption is still insufficient to absorb it. The advantage is

that electricity production need not be drastically scaled up and down to meet momentary

consumption and instead transmission from the combination of generators plus storage

facilities is maintained at a more constant level.

• An alternate approach to achieve the same effect is to use a smart grid communication

infrastructure to enable Demand Response (DR). Both of these technologies shift energy

usage and transmission of power on the grid from one time to another when it's really

needed.

• Energy storage is essential to balance supply and demand. Peaks and gutters in demand

can often be anticipated and managed by increasing, or decreasing generation at fairly short

notice. In a low-carbon system, intermittent renewable energy (RES) makes it more difficult to

vary output, and rises in demand do not necessarily correspond to rises in RES generation.

Hence higher levels of energy storage are required for grid flexibility and stability and to cope

with the increasing use of intermittent wind and solar electricity.

The energy storage and demand response has the following advantages:

• Electricity generated by (or with the potential to be generated by) intermittent sources can be

stored and used later, whereas it would otherwise have to be transmitted elsewhere.

• Peak generating or transmission capacity can be reduced by the total potential of all storage

plus deferrable loads saving expense of this capacity

• The cost of the storage and/or demand management is included in pricing so there is less

variance in power rates charged to customers.

• Critical requirements can be met reliably even with no transmission or generation going.

J) Electric charging vehicle

Fig: Electric vehicle charging station

Conventional cars produce a lot of carbon emissions that are ejected into our natural atmosphere,

leaving us vulnerable to things like pollution and greenhouse gases. In order to help positively the

environment we live in, an electric car is a great step forward. By buying an electric car, you can

also receive government subsidies for being environmentally conscious. Although you may end

up paying more for your vehicle, the positives greatly overshadow the negatives.

Advantages

• Low emission as compared to conventional fuel fired vehicles.

Electric cars are eco-friendly as they run on electrically powered engines. It does

not emit any toxic gases in the environment as it runs on clean energy source. It is

surely contributing to a healthy and green climate.

• Cost effective and low maintenance.

More technological advancements have brought down the cost of electrical

vehicles. As electric cars runs on electrically powered engines, there is no need to

lubricate the engines. Also, there is no other auxillary expenditure like

conventional vehicles. In view of the above, the maintenance cost of these cars has

come down drastically.

• Reduced noise pollution

There is virtually no noise pollution from electric vehicles and hence it is quite

environment friendly.

Disadvantages

• Less recharge points.

Electric fuelling stations are still in the development stages. There are not many

electric fuelling stations for your vehicle. If you’re on a long trip and if no electric

charging stations exist in the vicinity, then you may be stuck where you are.

• Short Driving Range and Speed.

Electric cars are limited by range and speed. Most of these cars have shorter range

and need to be recharged again. Hence you can’t use them for long journeys as of

now.

• Longer Recharge Time

As compared to a conventional vehicle, an electric car take about 4-5 hours to get

fully charged. Therefore, you need dedicated charging stations as the time taken to

recharge them is quite long.

• Frequent Battery Replacement

Depending on the type and usage of battery, batteries of electric cars are required

to be changed every 3-6 years.

• Normal electric vehicles are 2/4 seaters

Most of the electric cars are small and 2 or 4 seated only. They are not meant for a

bigger group or family.

Benefits of Smart Grid to Consumers

• A major benefit of Smart Grid is that it empowers consumers to drastically improve the

management of their individual energy usage.

• Smart grid will create a new lifestyle for electricity consumers. Today, customers do not

know how the energy they consume is produced and delivered to them. With smart grid

technologies, consumers will be able to know exactly how much electricity they consume

in their house. Today, customers simply pay the energy bill towards the end of the month

without having the knowledge of their consumption pattern. In smart grid environment

consumers will be able to keep track of how much energy they are using and for what

purpose.

• It will encourage less waste, reduce consumption and help consumers become more

conscious of their environment.

• Customers will be able to achieve more sustainable lifestyles that minimize energy waste

and maximize the use of clean energy.

• Customers can interact with the electricity markets through home area network and smart

meter connectivity.

• Reduce carbon emission by using electric vehicles.

• Enable customers to sell the excess power generated back to the grid.

Benefits of Smart Grid to Utilities

• Reduced operational and capital costs.

• Increased efficiency of operation and enhanced customer satisfaction.

• Increased revenues as power theft gets reduced drastically. Smart Grid systems provide

tamper proof and theft proof systems which can easily detect power pilferage.

• Better cash flow due to the efficient management of revenue realisation mechanism in

smart grid.

• Reductions in peak load and energy consumption leading to deferral of future capital

investments.

• Extended life of system assets through improved power quality management.

• Increase in employee efficiency has led to the improved and more systematic operational

and maintenance activities.

• More accurate load forecasting is made possible due to availability of accurate

information on supply and demand.

• Reduction in emissions as a result of greener power generation from wind, solar etc,

reduced system losses, and energy conservation.

• Reduction in frequency of failure of distribution transformers as the information

regarding operating parameters of these transformers which the system captures help

operator to undertake advance preventive maintenance.

Financial Benefits of Smart Grid

• Reducing generation costs

Electric power is provided with a combination of generating assets including high capital cost-

intensive coal based, hydroelectric, and nuclear plants. These power plants provide the most

economical source of electricity. Also there are intermediate of combined cycle natural gas

plants that produce electricity at a higher cost than base-load units. These costs can be

considerably reduced with judicious implementation of distributed generation.

• Reducing operating costs

Conventional utilities incur huge expenditure for meter reading, customer services, field services,

collections, theft management and other functions, many of which are almost eliminated with

smart grid systems. For example, meters are read, connected and disconnected, evaluated for

theft and other activities all through software administered remotely by the utility systems.. Grid

outages are more accurately identified reducing costs of restoring power. Much of the

traditional utility field inspection and maintenance activities are avoided.

Smart Grid issues needing more focus and research

The following topics are of paramount important in the development of Smart Grid:-

Interoperability and cyber security

• Communications networks provide the backbone of smart grids conveying information from

customer end throughout the distribution system back to the utility. Depending on the

communications systems being used, these data may be concentrated and/or relayed four or

five times before they reach the utility.

• In addition, appliance data within each facility must be transmitted to the meter and passed

along as well. The ability of equipment from different manufacturers to communicate with

one another and to communicate with different kinds of equipment to transfer information is

important in ensuring a smoothly functioning communications and information system.

• Added to it, each communication system is subject to cyber security threats. Both

interoperability and cyber security have been a serious concern and a lot of policy framework

has to be evolved to eliminate the hindrances which they can pose.

Privacy

• With all of the information streaming from utility customer facilities, it is no wonder that

privacy has become a great concern. 15-minute electric load profiles can reveal much

about each facility ranging from when the facility is occupied to what appliances are

being used etc. The important question is that how these data is to be used and who all

has got right to these data has not been resolved. The general opinion is that the electric

usage data is personal and cannot be shared without permission of the utility customer.

Regulatory issues

• Who pays and who benefits is one of the regulatory issues lingering for quite some time.

For many smart grid applications this is not an issue; however, reactive compensation

optimization is a good example of where regulatory issues are a problem. Reactive

compensation optimization reduces voltage, losses and improves efficiency throughout

the year but it also reduces electricity use by customers and consequently reduces utility

revenue.

• Expecting utility management, who is accountable to stockholders, to invest in improving

distribution efficiency resulting in reduced revenues without some offsetting

compensation is unrealistic. Regulatory bodies have addressed some of these issues;

however, regulatory balancing of shareholder and customer interests continues to delay

some smart grid investments.

IT and data management systems

• Smart meters typically provide automated meter readings at 15-minute intervals from

each meter. The data must be cleansed and verified to identify possible errors in

transmission or metering and then passed on the appropriate utility management system

including outage management, distribution management, billing exceptions, asset

management etc.

• Additional information from distribution system meters and equipment must be integrated

in this process and all of this information must be integrated and presented in such a way

that it provides value to the utility. This necessitates the enhancement of IT

infrastructure and IT systems which can meet these requirements backed up good IT

support team.

Future Road Map of Smart Grid

• More focus on making Smart Grid a techno-commercially viable system.

• Bring out the Smart Grid from the pilot phase into a commercial customer centric reality.

• Preparation of policy framework for smoother transition phase.

• More research to bring in more reliability, stability and dependability in Smart Grid.

• Make a balanced tradeoff in utilization of power from utility grid and distributed generation.

• Improve the operating efficient and reliability of communication technologies used in Smart Grid.

• Enhance the cyber security of enormous amount of data being handled from smart meters and other inter-related utility systems. However the security measures should be such that it does not compromise on the speed, effectiveness and dependability of Smart Grid.

• Frame an effective net metering policy for making a win-win situation for both utility and prosumer.

• Devise incentive measures to encourage new players in the market so that the Smart Grid products will become competitive in terms of pricing and performance.

• Work more on the acceptability of Smart Grid technology by the end users as well as the utility.

• More pilot implementation of Smart Grid projects to enhance the awareness and acceptability by consumers.

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References

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id_2_2012.pdf

3. http://www.ilgridplan.org/Shared%20Documents/ISSGC%20Collaborative%20Report.pdf

4.A Survey of Experiments Involving Dynamic Pricing of Electricity, EDI Quarterly 4(1):

15-18.

5. https://blogs.siemens.com/smartgridwatch/stories/957/

6. http://www.nist.gov/smartgrid/upload/NIST_Framework_Release_2-0_corr.pdf

7.http://www.greentechmedia.com/articles/read/a-new-standard-for-the-smart-grid-ready-home-a

ppliance

8. www.wikipedia.org

9. www.smartgridnews.com

10.www.powergridindia.com