The document describes an undergraduate student project to locate faults in underground power cables. It presents the project overview, block diagram, components used including a microcontroller, ADC, relays, and LCD. Resistors are used to simulate cable lengths and faults are induced using switches. The voltage drop across resistors is measured and the distance displayed on the LCD based on calculations done by the microcontroller. Relays are used to select cable phases and the system is powered by a 5V regulator.

1. Presentation of Main Project on
“UNDERGROUND CABLE FAULT DISTANCE
LOCATOR”
Presented by
B2C005 AMIT CHAKRABORTY
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING
GOVT. COLLEGE OF ENGINEERING KANNUR- 670563
JANUARY 2016
1

2.  Project overview
 Block diagram
 Power supply
 Microcontroller
 ADC0804
 Relay
 Relay driver
 LCD
 Software requirements
 Schematic & Working of the project
 Advantages
 Applications
 Future scope
 Conclusion

3.  The project uses the simple concept of OHMs law
where a low DC voltage is applied at the feeder end
through a series resistor.
 The current would vary depending upon the length
of fault of the cable in case there is a short circuit
of LL or 3L or LG etc.
.

4.  The series resistor voltage drop changes
accordingly which is then fed to an ADC to develop
precise digital data which the programmed
microcontroller would display the same in Kilo
meters.
 The project is assembled with a set of resistors
representing cable length in KMs and fault creation
is made by a set of switches at every known KM to
cross check the accuracy of the same

7.  The 230V AC supply is first stepped down to 12V
AC using a step down transformer.
 This is then converted to DC using bridge rectifier.
 The AC ripples is filtered out by using a capacitor
and given to the input pin of voltage regulator
7805.
 At output pin of this regulator we get a constant 5V
DC which is used for MC and other ICs in this
project.

8.  It is a smaller computer
 Has on-chip RAM, ROM, I/O ports...
RAM ROM
I/O
Port
Timer
Serial
COM
Port
Microcontroller
CPU
A single chip

9. CPU
On-chip
RAM
On-chip
ROM for
program
code
4 I/O Ports
Timer 0
Serial
Port
OSC
Interrup
t
Control
External interrupts
Timer 1
Timer/Counter
Bus
Control
TxD RxDP0 P1 P2 P3
Address/Data
Counter
Inputs

10.  8K Bytes of In-System Programmable
(ISP) Flash Memory
 4.0V to 5.5V Operating Range
 Fully Static Operation: 0 Hz to 33 MHz
 256 x 8-bit Internal RAM
 32 Programmable I/O Lines
 Three 16-bit Timer/Counters
 Eight Interrupt Sources
 Full Duplex UART Serial Channel

12. +5V
30 pF
30 pF
8.2 K
10 uF
+
11.0592 MHz
EA/VPP
X1
X2
RST
31
19
18
9

13.  Analog to digital converters find huge
application as an intermediate device to
convert the signals from analog to digital
form.
 These digital signals are used for further
processing by the digital processors.
 Various sensors like temperature, pressure,
force etc. convert the physical characteristics
into electrical signals that are analog in
nature.

14.  ADC0804 is a very
commonly used 8-bit
analog to digital
convertor.
 It is a single channel IC,
i.e., it can take only one
analog signal as input.

15.  Compatible with microcontrollers, access
time is 135ns.
 Logic inputs and outputs meet both MOS
and TTL voltage level specifications.
 Works with 2.5V (LM336) voltage reference.
 On-chip clock generator.
 0V to 5V analog input voltage range with
single 5V supply.
 20-pin molded chip carrier or small outline
package.
 Operates ratio metrically or with 5 VDC, 2.5
VDC, or analog span adjusted voltage
reference.

16.  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.

17.  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

18.  ULN is Relay driver application
 The ULN2003 is a monolithic high voltage
and high current Darlington transistor arrays.
 It consists of seven NPN Darlington pairs that
features high-voltage outputs with common-
cathode clamp diode for switching inductive
loads.
 The collector-current rating of a single
Darlington pair is 500mA.
 The Darlington pairs may be paralleled for
higher current capability.

19.  The ULN functions as
an inverter.
 If the logic at input
1B is high then the
output at its
corresponding pin
1C will be low.

20.  Most common LCDs connected to the microcontrollers are
16x2 and 20x2 displays.
 This means 16 characters per line by 2 lines and 20
characters per line by 2 lines, respectively.
 The standard is referred to as HD44780U, which refers to the
controller chip which receives data from an external source
(and communicates directly with the LCD.

21.  If an 8-bit data bus is used the LCD will
require 11 data lines(3 control lines plus the
8 lines for the data bus)
 The three control lines are referred to as EN,
RS, and RW
 EN=Enable (used to tell the LCD that you are
sending it data)
 RS=Register Select. When RS=0; data is
treated as a command & When RS=1; data
being sent is text data.
 R/W=Read/Write . When RW=0; the data
written to the LCD & When RW=0; the data
reading to the LCD.

22.  Keil an ARM Company makes C compilers, macro
assemblers, real-time kernels, debuggers, simulators,
integrated environments, evaluation boards, and
emulators for ARM7/ARM9/Cortex-M3,
XC16x/C16x/ST10, 251, and 8051 MCU families.
 Compilers are programs used to convert a High Level
Language to object code. Desktop compilers produce an
output object code for the underlying microprocessor,
but not for other microprocessors.

23.  i.e., the programs written in one of the HLL like ‘C’ will
compile the code to run on the system for a particular
processor like x86 (underlying microprocessor in the
computer).
 For example compilers for Dos platform is different from
the Compilers for Unix platform So if one wants to define a
compiler then compiler is a program that translates source
code into object code.

24.  The project uses a set of resistances in series i.e.
R10,R11,R12,R13 and R17,R16,R14,R21,
R20,R19,R18,R25,R22 as shown in the circuit
diagram, one set for each phase.
 Each series resistors represents the resistance of
the underground cable for a specific distance
thus 4 such resistances in series represent 1-
4kms.
 3 relays are used to common point of their
contacts are grounded while the NO points are
connected to the input of the R17, R21 & R25
being the 3 phase cable input.
 R10 is fed with a series resistor R1 to 5v supply.
The common point of R10 & R1 is given to input
pin of 6 of ADC0804 duely wired as explained
above.