ppt of Three phase fault analysis with auto reset for temporary fault and trip for permanent fault

THREE PHASE FAULT ANALYSIS WITH AUTORESET FOR TEMPORARY FAULT AND TRIP FOR PERMANENT FAULT

GUIDE :- DR. RAJASHEKAR P. MANDI

(PROFESSOR)

REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT, BANGALORE-560064

Electrical and Electronics Engineering Department

Name USN NOSHASHANK SMAR THAYEEB PASHAUJJWAL KARNVIKRAM KUMAR RAWANI

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ACKNOWLEDGMENT• We are highly indebted to Dr. Rajashekar P. Mandi for his guidance and

constant supervision as well as for providing necessary information regarding the project.

• We would like to express our gratitude to the HOD-Dr.Puttamadappa C for his kind co-operation and encouragement.

• We would like to express our special gratitude and thanks to our PRINCIPAL- Dr. Sunil S. Manvi for giving us such attention and time.



ABSTRACT• This project provides automatic tripping mechanism for the three phase supply system

for prevention from damage due to faults.

• In case of temporary fault: the output resets automatically after a brief interruption.

• In case of permanent fault: the output remains in tripped condition .

• Faults like LG, LL, LLL and so on can be sensed and automatically disconnects

the supply to avoid large scale damages to the equipment connected.

• Step down transformers bring down the voltage from 230V to 12V.The concept of low voltage testing of fault conditions is followed.

• A set of switches are used to create faults and 555 timers are used to handle short and long duration fault condition.



INTRODUCTION



• Various studies have shown that anywhere from 70%, to as high as 90%, of faults on most overhead lines are transient .

• Faults tend to be less transient (near the 80% range) at lower distribution voltages and more transient (near the90% range) at higher sub transmission and transmission voltages .

• Causes of transient fault: Lightning, swinging wires, temporary contacts with foreign objects.

• The remaining 10 - 30% of faults are semi-permanent or permanent in nature.

• Transient faults can be cleared by momentarily de-energizing the line, in order to allow the fault to clear. Auto-reclosing can then restore service to the line

• Permanent fault will not be cleared by tripping and auto-reclosing.

OBJECTIVES



• To reduce the outage time due to faults and provide higher level of service continuity to the customers.

• To maintain system stability.

• To send message to the authorities via sms by interfacing a GSM modem.

COMPONENTS:• STEP DOWN TRANSFORMER• 555 TIMER• VOLTAGE REGULATOR(LM 7805)• RELAYS• COMPARATOR IC LM358• OPTOCOUPLER (MCT 2E)• CAPACITORS , DIODES, RESISTORS,TRANSISTORS, LEDS, PUSH BUTTON• MICROCONTROLLER(89S52)• MAX 232• GSM MODEM• LCD (16 X 2)

BLOCK DIAGRAM

CIRCUIT DIAGRAM

CONNECTIONS:

• Six number of step down transformers (220v to 12v) are used.•The primaries of 3 transformers are connected to the supply in star configuration and their secondaries are connected in star.•The other set of 3 transformers are connected in star – delta configuration.•The output of all transformers are rectified and filtered individually and are given to 6 relay coils•6 push buttons are connected across each relay to create fault.•The NC contacts are connected in parallel while all COM points are grounded.•Parallel connected point of NC is connected to pin 2 of 555 timer (mono-stable mode)•Output of this timer is given to the reset pin of next 555 timer(astable mode)•From pin 3 of this timer output is given to the non-inverting input pin of comparator IC LM358 , while the inverting input is kept at a fixed voltage by a potential divider.•Pin 1 of LM358 is connected to 3 CO relay through the driver transistor Q1.

RELAY

• A relay is an electrically operated switch.• Many relays use an electromagnet to operate a switching mechanism mechanically, but other operating principles are also used.• Relays are used where it is necessary to control a circuit by a low-power signal (with complete electrical isolation between control and controlled circuits), or where several circuits must be controlled by one signal.

555 TIMER

PIN NAME PURPOSE 1 GND Ground , low level (0 V)

2 TRIG Output rises and interval starts when input falls below 1/3 Vcc

3 OUT This output is driven to +Vcc or Gnd

4 RESET A timing interval may be interrupted by driving this input to GND

5 CTRL Control access to the internal voltage divider(by default,2/3 Vcc

6 THR The interval ends when the voltage at THR is greater than at CTRL

7 DIS Open collector output, may discharge capacitor between intervals

8 V+, Vcc Positive supply voltage is usually between 3 and 15 V

ASTABLE MODEMONOSTABLE MODE

COMPARATOR (IC LM358)

Pin Connection 1 - Output 1 2 - Inverting input 3 - Non-inverting input 4 – VCC- 5 - Non-inverting input 2 6 - Inverting input 2 7 - Output 2 8 – VCC+

• 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.

• It is designed always to be used in closed-loop application.

LCD

PINS DESCRIPTION 1 Ground 2 Vcc 3 Contrast voltage 4 “R/S”-Instruction/Register Select 5 “R/W”-Read/write LCD registers 6 “E” clock 7-14 Data input/output pins

• LCD are electronically modulated optical device shaped into a thin,flat panel made up of any number of colour or monchrome pixels filled with liquid crystals. These crystals are arrayed in front of light source or reflector.

• Any LCD controller is used to provide a simple interface to an LCD,perhaps eight data inputs and one enable input

MICROCONTROLLERThe 89C52 is a single chip microcomputer with I/O port, timer, clock generator, Data memory, program memory stack, ADC and serial ports etc. • 8 bit CPU with registers A and B. • 16 bit Program Counter and Data Pointer.• 8 bit Program Status Word. • 8 bit stack pointer.• Internal ROM of 8K bytes. • Internal RAM of 256 bytes, 4 register banks each containing 8registers. • Two 16 bit timer / counter. • Full duplex serial data receiver/transmitter. • Special function registers like TCON, TMOD and SCON etc. •Two external and three internal interrupt sources.

Microcontrollers are used in automatically controlled products and devices such as automobile engine control systems, home security systems, hotel security and monitoring systems, remote controls, office machines, appliances, power tools, and toys. By reducing the size and cost compared to a design that uses a separate microprocessor, memory, and input/output devices, microcontrollers make it economical to digitally control even more devices and processes.

GSM ARCHITECTURE

• A GSM network is composed of several functional entities, whose functions and interfaces are specified. Figure 4.16 shows the layout of a generic GSM network. The GSM network can be divided into three broad parts.

• The Mobile Station is carried by the subscriber. The Base Station Subsystem controls the radio link with the Mobile Station. The Network Subsystem, the main part of which is the Mobile services Switching Center (MSC), performs the switching of calls between the mobile users, and between mobile and fixed network users. The MSC also handles the mobility management operations. Not shown is the Operations and Maintenance Center, which oversees the proper operation and setup of the network.

MAX232

• MAX232 is an integrated circuit, dual driver/reciever and typically converts RX,TX,CTS and RTS signals.

• When a MAX232 IC receives a TTL level to convert, it changes TTL logic 0 to between +3V and +15V and changes TTL logic 1 to between -3V and -15V and vice versa for converting from TIA232 to TTL.

WORKING AND OPERATING PROCEDURE

WORKING: The project uses 6numbers step-down transformers for handling the entire circuit under low voltage conditions of 12v only to test the 3 phase fault analysis. The primary of 3 transformers are connected to a 3 phase supply in star configuration, while the secondary of the same is also connected in star configuration. The other set of 3 transformers with its primary connected in star to 3 phase have their secondary„s connected in delta configuration. The output of all the 6 transformers are rectified and filtered individually and are given to 6 relay coils. 6 push buttons, one each connected across the relay coil is meant to create a fault condition either at star i.e. LL Fault or 3L Fault. The NC contacts of all the relays are made parallel while all the common points are grounded. The parallel connected point of NC are given to pin2 through a resistor R5 to a 555 timer i.e. wired in monostable mode. The output of the same timer is connected to the reset pin 4 of another 555 timer wired in astable mode. LED„S are connected at their output to indicate their status. The output of the U3 555 timer from pin3 is given to an Op-amp LM358 through wire 11 and d12 to the non-inverting input pin3, while the inverting input is kept at a fixed voltage by a potential divider RV2. The voltage at pin2 coming from the potential divider is so held that it is higher than the pin3 of the Op-amp used as a comparator so that pin1 develops zero logic that fails to operate the relay through the driver transistor Q1. This relay Q1 is 3CO„ relay i.e. is meant for disconnecting the load to indicate fault conditions.

OPERATING PROCEDURE:

While the board is powered from a 3phase supply all the 6 relay coils get DC voltage and their common point disconnects from the NC and moves on to the NO points there by providing logic high at pin2 of 555 timer U1 i.e. that is kept on monostable mode. While any push button across the relay is pressed it disconnects that relay and in the process in common contacts moves to the NC position to provide a logic low at trigger pin of 555 timer to develop an output that brings the U3 555 timer which is used in astable mode for its reset pin to high such that the astable operation takes place at its output which is also indicated by flashing D11 LED. If the fault is off temporary in nature i.e. if the push button pressed is released immediately the U1 monostable disables U3 the output of which goes to zero in the event of any push button kept pressed for a longer duration the monostable output provides a longer duration active situation for U3 the astable timer the output of which charges capacitor C13 through R11 such that the output of the comparator goes high that drives the relay to switch off three phase load. The output of Op-amp remains high indefinitely through a positive feedback provided for its pin1 to pin3 through a forward biased diode and a resistor in series. This results in the relay permanently switched on to disconnect the load connected at its NC contacts permanently off. In order to maintain the flow of DC supply the star connected secondary set DC„S are paralleled through D8,D9 & D10 for uninterrupted supply to the circuit voltage of 12v DC and 5v DC derived out of voltage regulator IC 7805.

RESULT

• When push button across RG supply was pressed and released immediately , the bulbs turned off and turned on automatically after 1.1sec (t=1.1R7.C9) . The message “RG temporary fault” was displayed on the LCD and same message was sent via GSM to the given mobile number. Similar results were obtained for YG/BG/RY/BY/RB temporary faults.

•When push button across RG supply was pressed for around 10 sec, the bulbs turned off but the bulbs didn‟t turn on even after the push button was released. The message “RG permanent fault” was displayed on the LCD and same message was sent via GSM to the given mobile number. Similar results were obtained for YG/BG/RY/BY/RB permanent faults.

• ADVANTAGES:

1. Safety equipment

2. More reliable

3. More efficient

4. Reduce losses

APPLICATIONS: Substation

Transmission lines

Industries

Apartments

Various faults have been created to develop an automatic tripping mechanism for the three phase supply system while temporary fault and permanent faults occur. Here timer 555 has been used with relay for the fault analysis. Short duration fault returns the supply to the load immediately called as temporary trip while long duration shall result in permanent trip. Also we adjust the time duration for permanent fault by adjusting capacitors charging periods. Whenever any type of fault: LG temporary/permanent or LL temporary / permanent occurs message regarding faults is displayed on LCD and also message is sent to the concerned person via GSM modem.

CONCLUSION

HARDWARE CIRCUIT WITH MODEL

PROGRESS REPORT NO: