Smart load shedding and price-based energy

management using microcontroller

Dr.S.M.Kannan, HOD, Department of Electrical and Electronic Engineering,

K.L.N.College of Engineering , Pottapalayam,Sivagangai District,Tamilnadu ,India. N.Nivetha,B.Preethipasri,K.Nevadhaa devi, Department of Electrical and Electronic Engineering, K.L.N.College of

Engineering , Pottapalayam,Sivagangai District,Tamilnadu ,India. Abstract-Recently, motivated by the rapid growth of electricity consumptions and the urgent need of reducing global carbon emission, the research on the smart grid has drawn wide attentions . To reduce the long term electricity cost of smart appliances (SAs) with deferrable operation time in smart grid, we propose a novel energy buffering framework to intelligently schedule the distributed energy storage (DES) for the cost reduction of SAs in this paper. The proposed energy buffering framework determines the action policy (e.g., charging or discharging) and the power allocation policy of the DES to provide DES power to proper SAs at proper time with lower price than that of the utility grid, resulting in the reduction of the long term financial cost of SAs. Specifically, we first formulate the optimal decision problem in the energy buffering framework as a discounted cost Markov decision process (MDP) over infinite-horizon. Then, we propose an optimal scheme for the energy buffering framework to solve the discounted cost MDP based on online learning approach. Keywords—Pic microcontroller,Current transformer,potential transformer,LCD,ULN2003.

I. INTRODUCTION

Time-based pricing is a pricing strategy where the provider of

a service or supplier of a commodity, may vary the price depending on the time-of-day when the service is provided or

the commodity is delivered. The rational background of time-based pricing is expected or observed change of the supply and

demand balance during time. Time-based pricing includes fixed time-of use rates for electricity and public transport, dynamic

pricing reflecting current supply-demand situation or differentiated offers for delivery of a commodity depending on

the date of delivery (futures contract). Most often time-based pricing refers to a specific

practice of a supplier. Live dynamic pricing is recommendable for utilities both in

regulated or market based environment. The use of live dynamic pricing is not limited in case of low difference between peak- and off-peak demand, unavailability of adequate time-of-use metering. Also, customer response to time-based pricing should be considered (see: Demand response).

A regulated utility will develop a time-based pricing schedule on analysis of its cost on a long-run basis, including both operation and investment costs. A utility operating in a market environment, where electricity (or other service) is auctioned on a competitive market, time-based pricing will reflect the price variations on the market. Such variations include both regular oscillations due to the demand pattern of users, supply issues (such as availability of intermittent natural resources: water flow, wind), and occasional exceptional price peaks.

Many of the Smart Grid Investment Grant (SGIG) projects that invest in smart meters also choose to introduce various

forms of time-based rate programs to their customers. These programs range from time-of-use to real-time pricing and are frequently referred to with terms such as time-differentiated retail rates, time-variant pricing, advanced pricing programs, and time-varying retail pricing. We refer to all of these as time-based rate programs—in which prices vary over time and different prices are in effect for different hours on different days.

Because electric power companies are generally monopoly utilities, regulatory agencies approve prices for electricity to consumers. These prices are referred to as electricity rates or tariffs. Sometimes a distinction is made between prices or rates on the one hand and tariffs on the other. In these instances, a tariff is an approved collection of different rates that utilities offer to specific but different types of customers (e.g., real-time pricing for large commercial and industrial customers vs. flat-rate for low-income residential customers). Electricity tariffs can be affected by the granularity, or precision, of electricity usage data that is recorded by the customer’s meter. Mass-market customers (i.e., residential and small commercial) overwhelmingly have bulk usage meters with a single data register, which simply accumulates the usage over time.

All of the pricing programs listed above, except for TOU, are also commonly referred to as dynamic pricing because prices are not known with certainty ahead of time. TOU tariffs are not a type of dynamic pricing because the rate schedule is predetermined and static. Dynamic pricing programs allow customers and utilities to take greater advantage of grid and wholesale market variability and of the capabilities of smart grid customer systems. All of these forms of time-based rate programs are enabled by the investment and installation of smart meters. Currently, most of the SGIG projects that

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include time-based rate programs are relatively small-scale pilot programs, although several projects with smart meters and time-of-use rates involve system-wide implementation.

iHEM, an in-home energy management application, which decreases the cost of energy usage at home while causes the least comfort degradation for the consumers.Battery Aggregation scheme that organizes distributed power of electric vehicles (EVs) to produce the desired grid-scale power for frequency regulation.All the existing system did not consider the financial aspect of energy storage systems and appliance scheduling.

II. PROPOSED SYSYTEM

The proposed energy management solution learns and adapts

to the residential energy usage patterns. In this paper, we present a solution that involves both the residential customer and the utility company. We present a closed loop solution that forecasts the electricity demand of individual residential customers, aggregates the demand from residential customers in a neighborhood, and presents the aggregated demand to the utility company. The utility company can use this demand forecast for DR management and TOU price decisions. Based on the TOU pricing offered by the utility company, the residential loads are then scheduled within user comfort zones to optimize the power consumption by the residential users. Over time, the utility will learn the effect of varying TOU price on user demand and will therefore be able to predict the change in user demand as a result of TOU price. This will enable the utility to determine the TOU price based

on the predicted demand and available power supply on a given day. The focus of this paper is on the load forecasting in the home as well as in a neighborhood and presenting a novel appliance scheduling scheme which uses TOU or differential pricing. A residential customer’s daily activities are characterized by a list of tasks to be scheduled at preferred time intervals. Some of these tasks are persistent, as they consume electricity throughout the day (e.g., refrigerator), while others may be scheduled within a defined time interval (e.g., washer/dryer or oven). In this paper, the demand-side energy management problem

is considered as the scheduling of a customer’s daily tasks according to user-specified constraints and the TOU pricing offered by the utility company to achieve cost savings and peak demand reduction. An intelligent power management application is discussed for controlling appliances in the home and as well as for gathering data about the past usage schedules of the appliances. The contributions of this project are summarized as follows

A novel energy buffering framework for deferrable SAs is proposed, which is very important for the future implementation of SAs in the smart grid. We mathematically formulate the optimal decision problem in the energy buffering framework, which takes into accounts the real-time electricity price, as well as the practical characteristics of SAs and DES. We propose an optimal scheme to utilize an online learning approach to solve the optimal decision problem in the energy buffering framework. Extensive simulation results show that the proposed optimal scheme outperforms the

baseline schemes and the myopic scheme in long term electricity cost.

In this paper, we focus on the financial cost reduction of SAs with bursty energy usage patterns and can be deferred (e.g., clothes washer and dryer, dish washer, water heater), which would play more and more important role in future residential and commercial areas [9]. First, we propose a novel energy buffering framework, in which the charging/ discharging action policy and the power allocation policy of the DES are determined to provide power to proper SAs at proper time with lower price than that of the utility grid, as a result, the proposed framework could reduce the long term financial cost of SAs.

III. BLOCK DIAGRAM AND DESCRIPTION The figure shows the basic block diagram of the smart load shedding and energy management using Microcontroller. It consists of a PIC16F877A microcontroller ,battery,realys,RF receiver,RF transmitter,current transformer,and loads.

Fig 1.Block Diagram For Proposed System

Here the RF transmitter receives serial data and transmits it

wirelessly through RF through its antenna connected at pin4 of microcontroller.The transmitted data is received by an RF receiver operating at the same frequency as that of the transmitter.In the above block diagram the relay acts as an electrical switch that opens and closes under control of another electrical circuit.Current transformers are used so that ammeters and the current coils of other instruments and relays need not be connected directly to high voltage lines.

IV. HARDWARE

DESIGN A. PIC16F877A

A PIC microcontroller is a processor with built in memory and RAM and you can use it to control your projects (or build projects around it). So it saves you building a circuit that has separate external RAM,ROM and peripheral chips.

Pic microcontrollers Includes EEPROM,timers,analogue

comparators,UART. The PIC Micro is one of the most popular microcontrollers and in case you were wondering the difference between a microprocessor and a microcontroller is that a microcontroller has an internal bus with in built memory and peripherals.

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Fig 2. PIC16F877 Pin Diagram In fact the 8 pin (DIL) version of the 12F675 has an amazing

number of internal peripherals. These are Two timers,One 10bit ADC with 4 selectable inputs,An internal oscillator (or you can use an external crystal),An analogue comparator,1024 words of program memory,64 Bytes of RAM,12EEPROM memory,External interrupt (as well as interrupts from internal peripherals).External crystal can go up to 20MHz.And all of these work from within an 8 pin DIL package.

In the mid-range devices the memory space ranges from 1k to 8k (18F parts have more) - this does not sound like a lot but the processor has an efficient instruction set and you can make useful projects even with 1k e.g. LM35 temperature sensing project that reports data to the serial port easily fits within 1k.

B. Relay In the original form, the switch is operated by an

electromagnet to open or close one or many sets of contacts. Because a relay is able to control an output circuit of higher power than the input circuit, it can be considered, in a broad sense, to be a form of electrical amplifier.These contacts can be either Normally Open (NO), Normally Closed (NC), or change-over contacts. Normally-open contacts connect the circuit when the relay is

activated; the circuit is disconnected when the relay is inactive. It is also called Form A contact or "make" contact. Form A contact is ideal for applications that require to switch a high-current power source from a remote device.

Normally-closed contacts disconnect the circuit when the relay is activated; the circuit is connected when the relay is inactive. It is also called Form B contact or "break" contact. Form B contact is ideal for applications that require the circuit to remain closed until the relay is activated.

Fig 3. Relay Connection

Fig 2. PIC16F877 Pin Diagram

sion of the 12F675 has an amazing number of internal peripherals. These are Two timers,One 10bit ADC with 4 selectable inputs,An internal oscillator (or you can use an external crystal),An analogue comparator,1024 words of program memory,64 Bytes of RAM,128 Bytes of EEPROM memory,External interrupt (as well as interrupts from internal peripherals).External crystal can go up to 20MHz.And all of these work from within an 8 pin DIL

range devices the memory space ranges from 1k this does not sound like a lot but

the processor has an efficient instruction set and you can make useful projects even with 1k e.g. LM35 temperature sensing project that reports data to the serial port easily fits within 1k.

In the original form, the switch is operated by an electromagnet to open or close one or many sets of contacts. Because a relay is able to control an output circuit of higher power than the input circuit, it can be considered, in a broad

m of electrical amplifier.These contacts can be either Normally Open (NO), Normally Closed (NC), or

open contacts connect the circuit when the relay is activated; the circuit is disconnected when the relay is

also called Form A contact or "make" contact. Form A contact is ideal for applications that require to switch

current power source from a remote device.

closed contacts disconnect the circuit when the onnected when the relay is

inactive. It is also called Form B contact or "break" contact. Form B contact is ideal for applications that require the circuit to remain closed until the relay is activated.

Fig 3. Relay Connection

Change-over contacts control two circuits: one normally

open contact and one normallyForm C contact.

Relays are extremely useful when we have a need to control a large amount of current and/or voltage with a small electrical signal. The relay coil which produces the magnetic field may only consume fractions of a watt of power, while the contacts closed or opened by that magnetic field may be able to conduct hundreds of times that amount of power to a load.

In effect, a relay acts as a binary (on or off) amplifier. Just as with transistors, the relay's ability to control one electrical signal with another finds application in the construction of logic functions.

C. RF Module The RF module, as the name suggests, operatesFrequency. The corresponding frequency range varies between 30 kHz & 300 GHz. In this RF system, the digital data is represented as variations in the amplitude of carrier wave. This kind of modulation is known as Amplitude Shift Keying (ASK).

Fig 4. RF Pin Description Transmission through RF is better than IR (infrared) because of many reasons. Firstly, signals through RF can travel through larger distances making it suitable for long range applications. Also, while IR mostly operatesmode, RF signals can travel even when there is an obstruction between transmitter & receiver. Next, RF transmission is more strong and reliable than IR transmission. RF communication uses a specific frequency unlike IR signals which are aby other IR emitting sources.

D. ULN2003

ULN2003 is a monolithic high voltage and high current Darlington array IC. It contains seven open collector darlington pairs with common emitters. A darlington pair is an arrangement of two bipolar transis

ULN2003 belongs to the family of ULN200X series of ICs. Different versions of this family interface to different logic families. ULN2003 is for 5V TTL, CMOS logic devices. These ICs are used when driving a wide range of loads and are used as relay drivers, display drivers, line drivers etc. ULN2003 is also commonly used while driving Stepper Motors. Refer Stepper Motor interfacing using ULN2003.

over contacts control two circuits: one normally-open contact and one normally-closed contact. It is also called

Relays are extremely useful when we have a need to control a large amount of current and/or voltage with a small

ical signal. The relay coil which produces the magnetic field may only consume fractions of a watt of power, while the contacts closed or opened by that magnetic field may be able to conduct hundreds of times that amount of power to a load.

elay acts as a binary (on or off) amplifier.

Just as with transistors, the relay's ability to control one electrical signal with another finds application in the construction of logic functions.

The RF module, as the name suggests, operates at Radio Frequency. The corresponding frequency range varies between 30 kHz & 300 GHz. In this RF system, the digital data is represented as variations in the amplitude of carrier wave. This kind of modulation is known as Amplitude Shift Keying

Fig 4. RF Pin Description

Transmission through RF is better than IR (infrared) because of many reasons. Firstly, signals through RF can travel through larger distances making it suitable for long range applications. Also, while IR mostly operates in line-of-sight mode, RF signals can travel even when there is an obstruction between transmitter & receiver. Next, RF transmission is more strong and reliable than IR transmission. RF communication uses a specific frequency unlike IR signals which are affected

ULN2003 is a monolithic high voltage and high current Darlington array IC. It contains seven open collector darlington pairs with common emitters. A darlington pair is an arrangement of two bipolar transistors.

ULN2003 belongs to the family of ULN200X series of ICs. Different versions of this family interface to different logic families. ULN2003 is for 5V TTL, CMOS logic devices. These ICs are used when driving a wide range of loads and are

rivers, display drivers, line drivers etc. ULN2003 is also commonly used while driving Stepper Motors. Refer Stepper Motor interfacing using ULN2003.

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Fig 5. ULN2003 Pin Configuration

Each channel or darlington pair in ULN2003 is rated at

500mA and can withstand peak current of 600mA. The inputs and outputs are provided opposite to each other in the pin layout. Each driver also contains a suppression diode to dissipate voltage spikes while driving inductive loads E. Current transformer

In electrical engineering, a current transformer (CT) is used for measurement of electric currents. Current transformers, together with voltage transformers (VT) (potential transformers (PT)), are known as instrument When current in a circuit is too high to directly apply to measuring instruments, a current transformer produces a reduced current accurately proportional to the current in the circuit, which can be conveniently connected to measuring and recording instruments. A current transformer also isolates the measuring instruments from what may be very high voltage in the monitored circuit. Current transformers are commonly used in metering and protective relays in the electrical power industry.

Current transformers used in metering equipment for threephase 400 ampere electricity supply.A current transformer has a primary winding, a magnetic core, and a secondary winding. The alternating current flowing in the primary produces a magnetic field in the core, which then induces a current in the secondary winding circuit. A primary objective of current transformer design is to ensure that the primary and secondary circuits are efficiently coupled, so that the secondary current bears an accurate relationship to the primary current.

The most common design of CT consists of a length of wire wrapped many times around a silicon steel ring passed over the circuit being measured. The CT's primary circuit therefore consists of a single 'turn' of conductor, with a many tens or hundreds of turns. The primary winding may be a permanent part of the current transformer, with a heavy copper bar to carry current through the magnetic core. Window-type current transformers are also common, which can have circuit cables run through the middle of an opening in the core to provide a single-turn primary winding. When conductors passing through a CT are not centered in the circular (or oval) opening, slight inaccuracies may occur.

Shapes and sizes can vary depending on the end user or

Fig 5. ULN2003 Pin Configuration

pair in ULN2003 is rated at 500mA and can withstand peak current of 600mA. The inputs and outputs are provided opposite to each other in the pin layout. Each driver also contains a suppression diode to dissipate voltage spikes while driving inductive loads.

In electrical engineering, a current transformer (CT) is used for measurement of electric currents. Current transformers, together with voltage transformers (VT) (potential transformers (PT)), are known as instrument transformers. When current in a circuit is too high to directly apply to measuring instruments, a current transformer produces a reduced current accurately proportional to the current in the circuit, which can be conveniently connected to measuring and

ording instruments. A current transformer also isolates the measuring instruments from what may be very high voltage in the monitored circuit. Current transformers are commonly used in metering and protective relays in the electrical power

nt transformers used in metering equipment for three-phase 400 ampere electricity supply.A current transformer has a primary winding, a magnetic core, and a secondary winding. The alternating current flowing in the primary produces a

core, which then induces a current in the secondary winding circuit. A primary objective of current transformer design is to ensure that the primary and secondary circuits are efficiently coupled, so that the secondary current

p to the primary current.

The most common design of CT consists of a length of wire wrapped many times around a silicon steel ring passed over the circuit being measured. The CT's primary circuit therefore consists of a single 'turn' of conductor, with a secondary of many tens or hundreds of turns. The primary winding may be a permanent part of the current transformer, with a heavy copper bar to carry current through the magnetic core.

type current transformers are also common, which t cables run through the middle of an opening

turn primary winding. When conductors passing through a CT are not centered in the circular (or oval) opening, slight inaccuracies may occur.

on the end user or

switchgear manufacturer. Typical examples of low voltage single ratio metering current transformers are either ring type or plastic moulded case. Highmounted on porcelain bushings to insulate them Some CT configurations slip around the bushing of a highvoltage transformer or circuit breaker, which automatically centers the conductor inside the CT window.

The primary circuit is largely unaffected by the insertion of the CT. The rated secondary current is commonly standardized at 1 or 5 amperes. For example, a 4000:5 CT would provide an output current of 5 amperes when the primary was passing 4000 amperes. The secondary winding can be single ratio or multi ratio, with five taps being comThe load, or burden, of the CT should be of low resistance. If the voltage time integral area is higher than the core's design rating, the core goes into saturation towards the end of each cycle, distorting the waveform and affecti

F. Potential transformer A potential transformer is a device that transfers electrical

energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primarymagnetic flux in the transformer's core and thus a varying magnetic field through the secondarymagnetic field induces a varying electromotive force (EMF), or "voltage", in the secondary winding. This effect is called inductive coupling.

If a load is connected to the secondary, current will flow in the secondary winding, and electrical energy will be transferred from the primary circuit through the transformer to the load. In an ideal transformer, the induced voltage in secondary winding (Vs) is in proportion to the primary voltage (Vp) and is given by the ratio of the number of turns in the secondary (Ns) to the number of turns in the primary (follows:

By appropriate selection of the ratio of turns, a trthus enables an alternating current (AC) voltage to be "stepped up" by making Ns greater than making Ns less than Np. In the vast majority of transformers, the windings are coils wound around a ferromagnetic core, aircore transformers being a notable exception.

Transformers range in size from a thumbnail

transformer hidden inside a stage microphone to huge units weighing hundreds of tons used to interconnect portions of power grids. All operate on the samealthough the range of designs is wide. While new technologies have eliminated the need for transformers in some electronic circuits, transformers are still found in nearly all electronic devices designed for household ("mains") voltage. Transformers are essential for hightransmission, which makes longeconomically practical.

switchgear manufacturer. Typical examples of low voltage single ratio metering current transformers are either ring type or plastic moulded case. High-voltage current transformers are mounted on porcelain bushings to insulate them from ground. Some CT configurations slip around the bushing of a high-voltage transformer or circuit breaker, which automatically centers the conductor inside the CT window.

The primary circuit is largely unaffected by the insertion of econdary current is commonly standardized

at 1 or 5 amperes. For example, a 4000:5 CT would provide an output current of 5 amperes when the primary was passing 4000 amperes. The secondary winding can be single ratio or multi ratio, with five taps being common for multi ratio CTs. The load, or burden, of the CT should be of low resistance. If the voltage time integral area is higher than the core's design rating, the core goes into saturation towards the end of each cycle, distorting the waveform and affecting accuracy.

A potential transformer is a device that transfers electrical energy from one circuit to another through inductively

the transformer's coils. A varying primary winding creates a varying

magnetic flux in the transformer's core and thus a varying secondary winding. This varying

magnetic field induces a varying electromotive force (EMF), or "voltage", in the secondary winding. This effect is called

If a load is connected to the secondary, current will flow in the secondary winding, and electrical energy will be transferred from the primary circuit through the transformer to the load. In an ideal transformer, the induced voltage in the

) is in proportion to the primary voltage ) and is given by the ratio of the number of turns in the

) to the number of turns in the primary (Np) as

By appropriate selection of the ratio of turns, a transformer thus enables an alternating current (AC) voltage to be "stepped

greater than Np, or "stepped down" by . In the vast majority of transformers,

the windings are coils wound around a ferromagnetic core, air-e transformers being a notable exception.

Transformers range in size from a thumbnail-sized coupling transformer hidden inside a stage microphone to huge units weighing hundreds of tons used to interconnect portions of power grids. All operate on the same basic principles, although the range of designs is wide. While new technologies have eliminated the need for transformers in some electronic circuits, transformers are still found in nearly all electronic devices designed for household ("mains") voltage. Transformers are essential for high-voltage electric power transmission, which makes long-distance transmission

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G.LCD

An LCD is a small low cost display. It is easy to interface

with a micro-controller because of an embedded controller(the black blob on the back of the board).This controller is standard across many displays which means many micro-controllers have libraries that make displaying messages as easy as a single line of code.LCDs with a small number of segments, such as those used in digital watches and pocket calculators, have individual electrical contacts for each segment.An external dedicated circuit supplies an electric charge to control each segment. This display structure is unwieldy for more than a few display elements.Small monochrome displays

such as those found in personal organizers, or older laptop

screens have a passive-matrix structure employing super-twisted pneumatic (STN) or double-layer STN (DSTN) technology—the latter of which addresses a color-shifting problem with the former—and color-STN (CSTN)—wherein color is added by using an internal filter. Each row or column of the display has a single electrical circuit.

Fig 6. LCD Display

The pixels are addressed one at a time by row and column

addresses. This type of display is called passive-matrix addressed because the pixel must retain its state between refreshes without the benefit of a steady electrical charge. As the number of pixels (and, correspondingly, columns and rows) increases, this type of display becomes less feasible. Very slow response times and poor contrast are typical of passive-matrix addressed LCDs.

High-resolution color displays such as modern LCD

computer monitors and televisions use an active matrix structure. A matrix of thin-film transistors (TFTs) is added to the polarizing and color filters. Each pixel has its own dedicated transistor, allowing each column line to access one pixel. When a row line is activated, all of the column lines are connected to a row of pixels and the correct voltage is driven onto all of the column lines.

H.Maximum demand meter

Maximum Demand meter is used for monitoring thermal

loading in Power Distribution systems, Networks, Machines etc. It indicates maximum loading current over a period. Short-period current peaks are not registered but long overloads are registered.

In the Maximum Demand meter the measuring current

flows through the bimetal spiral which is temperature sensitive. The free end of the spiral is connected to a black measuring pointer. The moving system is activated by heat generated by the current flowing through the spiral. The instrument is provided with an additional red slave pointer with a higher friction, which makes it to remain at its maximum position, which determines the maximum average loading current.

The high torque of metallic movement drags the red pointer along with the black pointer. The red pointer remains stationary at the maximum value reached. This can be reset by rotating the knob provided on front facia. To prevent false indication due to fluctuations in ambient temperature, an additional bimetallic spiral is wound in opposite direction, which is mounted on the same spindle to compensate variation in temperature from -10 to + 55 degrees Centigrade.

Frequently there is a need to measure instantaneous current simultaneously & hence moving iron movement having the same range is incorporated in the same meter.

Fig 7. Maximum demand meter

V.PERFORMANCE AND RESULT

PIC16F877A is a 40 Pin DIP pack IC with 33 I/O pins. Out

of which 8 pins can be used either as Digital I/O pins or Analog Input pins. The micro controller is having 5 ports Port A, Port B, Port C, Port D and Port E. Here Port A consists of 6Pins and can be used as Analog Pins and Digital Pins, in the same way Port E consists of 3Pins all of them can either be used as Analog Pins or Digital Pins. The Port pins of Port D are connected to LCD pins. RD4 to RD7 as data pins and RD0 to RD2 as control pins. The Pins of Port B are connected to relay drivers, which in turn drives the relays. The Pins 13 and 14 are connected to Oscillators. This Oscillator provides required clock reference for the PIC micro controller. Either Pins 11 and 12 or 31 and 32 can be used as power supply pins. Pins 25 and 26 of Port C are used for serial Port communications; these pins are interfaced with MAX232 for PC based communications. Pins 37,38,39 and 40 are used for In-Circuit Debugger Operations, with which the hex code is downloaded to the Chip. Pin 33 is used as external Interrupt Pin. Pin 1 is used as Reset Pin. This Pin is connected to Vcc through a resistor.

The LCD we have used in this project is HD1234. This is an alphanumeric type of LCD with 16 pins. Of which Pins 7 to

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14 are used as data pins, through which an 8-bit data can be input to the LCD. These Pins are connected to the Port 0 of Micro controller. There are 3 control pins RS (Pin-4), RW (Pin-5) and EN (Pin-6). The RS pin is connected to the 28th Pin of micro controller. The RW pin is usually grounded. The Enable pin is connected to 27th Pin. The LCD has two Rows and 16 Columns. The LCD is powered up with 5V supply connected to Pins 1(Gnd) and 2(Vcc). The Pin 3 is connected to Vcc through a Potentiometer. The potentiometer is used to adjust the contrast level. Here in our project we use the PIC controller in 4-bit mode. Here only 4 data pins are connected and are used as Data Port.

The current transformer is connected in series with the load to measure the load current. The CT secondary windings are larger than primary winding, hence the voltage across the primary is stepped up in the secondary side. Since the voltage is stepped up, the current is stepped down. The secondary current is made to flow through the known resistance. Here the voltage is dropped, which is proportional to the secondary current. Since the secondary current is proportional to primary current, the voltage in turns represents the primary current. The voltage is then rectified in to DC voltage and the AC ripples are filtered using a capacitor. The analog DC output is fed to the analog channels of the PIC micro controller.

When AC is applied to the primary winding of the power transformer it can either be stepped down or up depending on the value of DC needed. In our circuit the transformer of 230v/15-0-15v is used to perform the step down operation where a 230V AC appears as 15V AC across the secondary winding. In the power supply unit, rectification is normally achieved using a solid-state diode. Diode has the property that will let the electron flow easily in one direction at proper biasing condition. As AC is applied to the diode, electrons only flow when the anode and cathode is negative. Reversing the polarity of voltage will not permit electron flow.A commonly used circuit for supplying large amounts of DC power is the bridge rectifier. A bridge rectifier of four diodes (4*IN4007) is used to achieve full wave rectification. Two diodes will conduct during the negative cycle and the other two will conduct during the positive half cycle. The DC voltage appearing across the output terminals of the bridge rectifier will be somewhat less than 90% of the applied RMS value. Filter circuits, which is usually capacitor acting as a surge arrester always follow the rectifier unit. This capacitor is also called as a decoupling capacitor or a bypassing capacitor, is used not only to ‘short’ the ripple with frequency of 120Hz to ground but also to leave the frequency of the DC to appear at the output. The voltage regulators play an important role in any power supply unit. The primary purpose of a regulator is to aid the rectifier and filter circuit in providing a constant DC voltage to the device. Power supplies without regulators have an inherent problem of changing DC voltage values due to variations in the load or due to fluctuations in the AC liner voltage. With a regulator connected to the DC output, the voltage can be maintained within a close tolerant region of the desired output. IC7812 and 7805 are used in this project for providing +12v and +5v DC supply.Use either SI (MKS) or

CGS as primary units. (SI units are strongly encouraged.) English units may be used as secondary units (in parentheses). This applies to papers in data storage. For example, write “15 Gbit/cm2 (100 Gbit/in2).”

An exception is when English units are used as identifiers in trade, such as “3½ in disk drive.” Avoid combining SI and CGS units, such as current in amperes and magnetic field in oersteds. This often leads to confusion because equations do not balance dimensionally.If you must use mixed units, clearly state the units for each quantity in an equation.

Fig 8 . Circuit Diagram

The SI unit for magnetic field strength H is A/m. However,

if you wish to use units of T, either refer to magnetic flux density B or magnetic field strength symbolized as µ0H. Use

the center dot to separate compound units, e.g., “A·m2.”

VI. CONCLUSION

The project “energy buffering” has been completed

successfully and the output results are verified. The results are in line with the expected output. The project has been checked with both software and hardware testing tools. In this work sensors and relays are chosen are proved to be more appropriate for the intended application. The project is having enough avenues for future enhancement. The project is a prototype model that fulfills all the logical requirements. The project with minimal improvements can be directly applicable for real time applications. Thus the project contributes a significant step forward in the field of peak demand mitigation, and further paves a road path towards faster development s in the same field. The project is further adaptive towards continuous performance and peripheral up gradations. This work can be applied to variety of industrial and commercial applications.

VII. ACKNOWLEDGEMENT

The authors are deeply grateful and thankful to the supervisor,the principal and the management of K.L.N.College of Engineering,Pottapalayam,Sivagangai for providing all facilities for this research paper.

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VIII. REFERENCES [1] H. Farhangi, “The Path of the Smart Grid,” IEEE Power and Energy Magazine, vol. 8, no. 3, pp. 18-28, Jan./Feb. 2010. [2] A.Q. Huang, M.L. Crow, G.T. Heydt, J. Zheng, and S. Dale, “The Future Renewable Electric Energy Delivery and Management (FREEDM) System: The Energy Internet,” Proc. IEEE, vol. 99, no. 1, pp. 133-148, Jan. 2011. [3] M. He, S. Murugesan, and J. Zhang, “Multiple Timescale Dispatch and Scheduling for Stochastic Reliability in Smart Grids with Wind Generation Integration,” Proc. IEEE INFOCOM, pp. 461-465,2011. [4] F. Katiraei, R. Iravani, N. Hatziargyriou, and A. Dimeas, “Microgrids Management,” IEEE Power and Energy Magazine, vol. 6, no. 3, pp. 54-65, May/June 2008. [5] S. Borenstein, M. Jaske, and A. Rosenfeld, “Dynamic Pricing, Advanced Metering, and Demand Response in Electricity Markets,” UC Berkeley: Center for the Study of Energy Markets, http://www.escholarship.org/uc/item/11w8d6m4, Oct. 2002. [6] B.P. Roberts and C. Sandberg, “The Role of Energy Storage in Development of Smart Grids,” Proc. IEEE, vol. 99, no. 6, pp. 1139-1144, June 2011. [7] S. Han, S. Han, and K. Sezaki, “Development of an Optimal Vehicle-to-Grid Aggregator for Frequency Regulation,” IEEE Trans. Smart Grid, vol. 1, no. 1, pp. 65-72, June 2010. [8] A. Saber and G. Venayagamoorthy, “Plug-in Vehicles and Renewable Energy Sources for Cost and Emission Reductions,” IEEE Trans. Industrial Electronics, vol. 58, no. 4, pp. 1229-1238, Apr.2011. [9] S. Newman, “Smart Appliances for an Energy-Efficient Future,” http://green.yahoo.com, 2008.

JASC: Journal of Applied Science and Computations

Volume 5, Issue 6, June /2018

ISSN NO: 0076-5131

Page No:284