THREE PHASE FAULT ANALYSIS WITH AUTO RESET ON

TEMPORARY FAULT AND PERMANENT TRIP OTHERWISE

Submitted By : Submitted To :Mukesh Choudhary (2012PUSETBEEX00247) Mr. Arun NayakKaran Singh Solanki (2012PUSETBEEX00442) Assistant ProfessorManish Meena (2012PUSETBEEX00332) Porrnima UniversityMukesh Choudhary (2012PUSETBEEX01530)

Department Of Electrical EngineeringPoornima University, Jaipur

A Presentation On Major Project Topic

Contents Project overview

Block diagram

Transmission Line faults

Comparator

555 timer

Relay

Schematic & Working of the project

Advantages

Applications

Future scope

Conclusion

Project overview Three single phase transformers are wired in star input and star

output having input 220 volt and output at 12 volt.

The contact relays which are used energized from the output of comparators in the event of fault conditions by tracking the input voltage conditions for each phase at the input of the comparators.

Two 555 timers are used, one in monostable and the other in astable mode to drive a power relay that handles the load.

A Set of switches are used to introduce LL fault, LG fault ,3L short to get the comparator output to drive both the relays to disconnect the load.

Short duration fault returns the load immediately while long duration shall result in permanent trip.

Block diagram

Transmission line Faults Fault types include:

Single line to ground(LG)

Line to line(LL)

Double line to ground(LLG)

Three phase balanced

Comparator

op amps & comparators look very similar

But a comparator gives a logic output indicating the relative potentials on its two inputs

An op amp amplifies the differential voltage between its two inputs – and is designed always to be used in closed-loop applications

Contd... Potential dividers are connected to the inverting and non

inverting inputs of the op-amp to give some voltage at these terminals.

Supply voltage is given to +V and –V is connected to ground.

The output of this comparator will be logic high (i.e., supply voltage) if the non-inverting terminal input is greater than the inverting terminal input of the comparator.

If the inverting terminal input is greater than the non-inverting terminal input then the output of the comparator will be logic low (i.e., gnd).

555 Timer

The 555 Timer IC is an integrated circuit (chip)

implementing a variety of timer and multivibrator

applications.

The original name was the SE555 (metal can)/NE555

(plastic DIP) and the part was described as "The IC

Time Machine".

Depending on the manufacturer, the standard 555

package includes over 20 transistors, 2 diodes and

15 resistors on a silicon chip installed in an 8-pin

mini dual-in-line package (DIP-8)

PIN DIAGRAM OF 555 The 555 timer IC is a simple 8 pin DIL

package IC.

It can:

be used as a monostable

be used as an astable

source or sink 100mA

use supply voltages of 5v to 15v

disrupt the power supply - use a

decoupling capacitor!

Relay A relay is an electrically operated switch.

Current flowing through the coil of the relay creates a magnetic field which attracts a lever and changes the switch contacts.

The coil current can be on or off so relays have two switch positions and have double throw (changeover) switch contacts as shown in the diagram.

Contd.. Relays allow one circuit to switch a second circuit which can be

completely separate from the first.

For example a low voltage battery circuit can use a relay to switch a 230V AC mains circuit.

There is no electrical connection inside the relay between the two circuits, the link is magnetic and mechanical.

To drive relay through MC ULN2003 relay driver IC is used

Contd..

Working of project In this project two 555 timers are used 1 in monostable mode and

other in astable mode.

When any push button is pressed for a short time the load is disconnected only for that period indicating a temporary fault.

If the push button is pressed for longer time then the astable timer s activated and it causes a permanent fault and disconnects the load permanently.

Future scope

The concept in the future can be extended to developing a mechanism to send message to the authorities via SMS by interfacing a GSM modem.

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