second review using mc

8/7/2019 Second Review Using Mc

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POWER PLANT MONITORING

USING PIC MICROCONTROLLER


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Abstract Block Diagram Current Transformer Potential Transformers

Applications Advantages Disadvantages Controller Output

Tools


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ABSTRACT

The automatic control of the generation and the

power flow is very essential for the smooth andeffective operation of the multi-area

interconnected power system. There are three main control objectives in a

multi-area interconnected power system; firstobjective is that the total generation of the

interconnection, as a whole must be matched

moment to moment to the total prevailingcustomer demand.

This in itself can be achieved by the self-regulating forces of the system.


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ABSTRACT CONTD

Second objective is that the total generation ofthe interconnected power system is to beallocated among the participating control areasso that each area follows its own load changes

and maintains scheduled power flows over itsinter-ties with neighboring areas.

This can be achieved by area regulation. Thethird objective is that within each control area,its share of total system generation is to be

allocated among available area generatingsources for optimum area economy, consistentwith area security and environmentalconsiderations.


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ABSTRACT CONTD

Our project monitors the temperature, voltage

and current of the generator.

For each physical variable corresponding sensors

are used, temperature sensor and voltageconverter circuit this information are given tomicrocontroller via interfacing circuit.

Microcontroller will capture the all data anddisplay all the information in LCD. At the sametime if any abnormal condition arises controller

will on buzzer


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Power

Supply

Potential

Transfor

mer

Rectifie

rFilter

Current

Transformer

I/V

Converter

Rectifie

r &Filter

Micr

o

controller

Control

Unit

Load

Power

Supply

LCD Display

Temperature

Sensor


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-

+

D1

W01G

2

1

3

4

TX1

V1

C1

470uF

U1

7805

1 3VIN VOUT

C1

47uF

C1

0.1uF

R1

330

D2

LN211WP

1

2

JP1

1

2

1

2

230/9V

230V

POWER SUPPLY CIRCUIT FOR

MICROCONTROLLER


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` Initially 230 V AC supply is reduced to (0-9V) with thehelp of a step down transformer having a capacity of

500mA.

` Since the input voltage to the regulator IC should bemore than its output voltage, transformer secondaryvoltage is 9V.

` This low voltage is rectified with the help of bridgerectifier. The ripples are minimized with the help of

capacitor filter to get a smooth DC supply. The rating ofthe chosen capacitor filter is 1000F.


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` The regulated DC voltage is obtained by using a

regulator IC 7805. In the case of IC 7805, theunregulated DC voltage is applied to Pin 1, and theoutput is taken at Pin 3 and Pin 2 is grounded.

` Another capacitor filter of rating 10F is connected atthe output of regulator IC to eliminate the voltageoscillations at the output due to the large voltageoscillations at the input of the regulator.


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` Current Transformers (CTs) can be used for monitoringcurrent or for transforming primary current into reduced

secondary current used for meters, relays, controlequipment and other instruments. CTs that transform

current isolate the high voltage primary, permit groundingof the secondary, and step-down the magnitude of the

measured current to a standard value that can be safelyhandled by the instrument.

` The current transformer together with potential

transformer(PT)are known as Instrument transformer(IT).` The current measurement channel measuring up to 50A.

` The current to Voltage converter is used to convert theincoming current into voltage .


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Operation:

` Transformers (sometimes called "voltagetransformers") are devices used in electrical circuits tochange the voltage of electricity flowing in the circuit.Transformers can be used either to increase thevoltage (called "stepping up") or decrease the voltage

("step down").` When a current flows through a wire, it makes a

magnetic field around the wire. Also, if a wire is in amagnetic field that is changing, a current will flow inthe wire.

` Transformers only work with AC (alternating current)circuits. Since the AC current on the "incoming" wire isconstantly changing, the magnetic field it createschanges too.


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-

+

D1

W01G

2

1

3

4

TX1

V1

C1

470uF

U1

7805

1 3VIN VOUT

C1

47uF

C1

0.1uF

R1

330

D2

LN211WP

1

2

JP1

1

2

1

2

230/9V

230V

POWER SUPPLY CIRCUIT FOR LM35 &

MICROCONTROLLER


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` Initially 230 V AC supply is reduced to (0-9V) with thehelp of a step down transformer having a capacity of

500mA.

` Since the input voltage to the regulator IC should bemore than its output voltage, transformer secondaryvoltage is 9V.

` This low voltage is rectified with the help of bridgerectifier. The ripples are minimized with the help of

capacitor filter to get a smooth DC supply. The rating ofthe chosen capacitor filter is 1000F.


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` The regulated DC voltage is obtained by using a

regulator IC 7805. In the case of IC 7805, theunregulated DC voltage is applied to Pin 1, and theoutput is taken at Pin 3 and Pin 2 is grounded.

` Another capacitor filter of rating 10F is connected atthe output of regulator IC to eliminate the voltageoscillations at the output due to the large voltageoscillations at the input of the regulator.


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` A rectifier is a device which offers a lowresistance to the current in one direction and ahigh resistance in the opposite direction.

` Such a device is capable of converting A.C.

voltage into a pulsating D.C. voltage.` The rectifier employs one or more diodes. It

may be either a vacuum diode or asemiconductor diode.

` There are two types

` Half wave rectifier

` Full wave rectifier

` Bridge rectifier


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` Bridge rectifier is a full wave rectifier. It consists offour diodes , arranged in the form of a bridge .

` It utilizes the advantages of the full wave rectifierand at the same time it eliminates the need for a

centre tapped transformer.` The supply input and the rectified output are the two

diagonally opposite terminals of the bridge.


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` During the positive half cycle, the secondary terminal

A is positive with respect to terminal B.

` Now the diodes D1 and D3 are forward biased and

hence do not conduct.

` The current flows from terminal A to terminal Bthrough D1, load resistance RL and the diode D3 andthen through the secondary of the transformer.


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` During the negative half cycle, terminal B is positive

with respect to point A.

` Now diodes D2 and D4 are forward biased and hence

conduct.

` Diode D1 and D3 are reversed biased and hence donot conduct.

` The current flows from terminal B to terminal Athrough diode D2, the load resistance RL and diode

D4 and then through the secondary of thetransformer.


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` On both positive and negative half cycles of the A.C.

input, the current flows through the load resistanceRL in the same direction.

` The polarity of the voltage developed across RL is

such that the end connected to the junction of thediodes D1 and D2 will be positive.


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` Output from the rectifier unit having harmoniccontents , so we can provided the filter circuit, filtercircuit is used to reduce the harmonics.

` Here we can use the electrolytic capacitor` This eliminates the harmonics from both voltage and

current signals.


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` Voltage regulator is used to maintain the constant

voltage with the variation of the supply voltage and theload current,

` When specifying individual ICs within this family, the xxis replaced with a two-digit number, which indicates theoutput voltage the particular device is designed toprovide (for example, the 7805 has a 5 volt output, while

the 7812 produces 12 volts).` The 78xx line are positive voltage regulators, meaning

that they are designed to produce a voltage that ispositive relative to a common ground.


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` The LM35 is an integrated circuit sensor that can

be used to measure temperature with an electricaloutput proportional to the temperature (in oC)


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` It can measure temperature more accurately

than a using a thermistor.

` The sensor circuitry is sealed and not subject to

oxidation, etc.

` The LM35 generates a higher output voltage

than thermocouples and may not require that

the output voltage be amplified.


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` It has an output voltage that is proportional to theCelsius temperature.

` The scale factor is .01V/oC

` The LM35 does not require any external calibration ortrimming and maintains an accuracy of +/-0.4 oC at roomtemperature and +/- 0.8 oC over a range of 0 oC to +100oC.

` Another important characteristic of the LM35DZ is thatit draws only 60 micro amps from its supply andpossesses a low self-heating capability. The sensor self-heating causes less than 0.1 oC temperature rise in stillair.


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Power generation (conventional and nuclear)

Distribution


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Automatic control

Safety


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` PIC16F877A Microcontroller


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` Prototype Model


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HARDWARE REQUIREMENTS

PIC16F877A Microcontroller

Temperature sensor

Voltage transformer

Current transformer Signal conditioning circuit

Power supply

LCD

Buzzer


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SOFTWARE REQUIREMENTS

MP Laboratory

Cadence


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WORK DONE

Power supply design for microcontroller &

temperature sensor


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WORK TO BE DONE

Hardware Implementation of full circuit

second review using mc

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