We can monitor, detect the fault type and fault distance of the underground line with Arduino UNO. This helps in improving Power Quality.

1. DEVELOPMENT OF AN
UNDERGROUND LINE FAULT DETECTOR
USING ARDUINO
Presented by
D. Nagasai
Electrical & Electronics Engineer

2. CONTENTS
 Abstract
 Proposed system
 Introduction
 Need
 Different underground faults
 Causes of faults in cables
 Fault detection method
 Methods of fault locating
 Circuit diagram
 Main components
 Program and flow chart
 Working
 Advantages
 Result
 Conclusion
 Future scope

3. ABSTRACT
 A fault defined as diverted current from the intended path
 The objective of this project is to detect the faults and abnormalities
occurring in underground cables using an Arduino.
 The basic idea behind the working of this project is ohm’s law.
 In case of a short circuit fault like L-G or L-L fault the change in voltage
value fed to the in-built ADC of the Arduino, this value is processed by the
Arduino and the fault is calculated in terms of distance from the base
station., This value is sent to the LCD interfaced to the Arduino board and
it displays exact location of the fault from base station.

4. PROPOSED SYSTEM

5. INTRODUCTION
 Underground fault detector deals with finding of exact fault location from
the base station itself.
 Cables have some resistance. We are mostly focus on that resistance only.
Resistance can vary with respect to the length of the cable. If the length of
the cable is enhancing, the value of the resistance will also enhanced. If
any variation happens in the resistance value, we will take that is fault spot
and finding that spot through Arduino technology.
 That fault spot is represents the standard of distance (kilometer) from the
base station, this value display by the display division.

6. NEED
 One of the major limitations of underground cable is the fault detection.
 Since the cables are laid under the surface, where the visual methods of
inspection don’t work effectively.
 This is not the case in Overhead Lines. In order to identify the faults in the
cable, we need to develop special methods, which will be discussed in this
project.
 Underground fault detector deals with finding of exact fault location from
the base station itself with micro controller based on the variation of the
resistance.

7. DIFFERENT UNDERGROUND CABLE FAULTS
 OPEN CIRCUIT FAULT
 SHORT CIRCUIT FAULT
 EARTH FAULTS

8. Open circuit fault
 These faults occur due to the failure of one or more conductors.
 The most common causes of these faults include joint failures of cables.
 Which is an infinite resistance between two nodes.

9. Short circuit fault
 A short circuit is an electrical circuit that allows a current to travel along an
unintended path with no or very low electrical impedance.
 This results in an excessive current flowing through the circuit.
 This is dangerous fault which can cause fire accidents.

10. Earth fault
 When any of the conductors of the cable comes in contact with the earth, it
is called an earth fault.
 This usually occurs when the outer sheath is damaged due to chemical
reactions with soil or due to vibrations and mechanical crystallization.
 It is somewhat similar to a short circuit fault as the current again takes the
least resistive path and flows through the earth.

11. CAUSES OF FAULTS IN CABLES
 Most of the faults occur when moisture enters the insulation.
 The paper insulation provided inside the cable is hygroscopic in nature.
Other causes include mechanical injury during transportation, laying
process or due to various stresses encountered by the cable during its
working life.
 The lead sheath is also damaged frequently, usually due to the actions of
atmospheric agents, soil and water or sometimes due to the mechanical
damage and crystallization of lead through vibration.

12. FAULT DETECTION METHODS
 ONLINE METHOD: utilizes and processes the sampled voltages and
current to determine the fault points.
 OFFLINE METHOD: special instrument is used to test out service of
cable in the field. This offline method can be divided into two methods.
1. TRACER METHOD: fault point is detected by walking on the cable
lines. Fault point is indicated from audible signal or electromagnetic
signal. It is used to pinpoint fault location very accurately.
2. TERMINAL METHOD: It is a technique used to detect fault location of
cable from one or both ends without tracing. This method use to locate
general area of fault, to expedite tracing on buried cable.

13. METHODS OF FAULT LOCATING
 TIME DOMAIN REFLECTOMETRY (TDR)
 MURRAY LOOP TEST (MLT)
 OHM`S LAW

14. Time Domain Reflectometry (TDR)
The TDR fed a signal through the cable happening without any
insulation degradation. If no faults occur in the cable the signal comes
back without any losses i.e. in a known shape. The consequence of TDR is
that it does not give exact faults.

15. Simple TDR & SC Fault output wave form

16. Murray Loop Test (MLT)
 In this method a bridge circuit used for detecting faults in underground or
water cables, it uses the principle used in potentiometer experiment. The
drawback of MLT is that it assumes only one fault exists at a time.
Murray tests kit

17. Ohm`s law
Ohm's law states that the current through a conductor between
two points is directly proportional to the voltage across the two
points. Introducing the constant of proportionality,
the resistance, one arrives at the usual mathematical equation that
describes this relationship

18. CIRCUIT DIAGRAM
Circuit diagram of Underground Line Fault Detector

19. MAIN COMPONENTS
 Power supply
 Arduino UNO (Atmega 328P)
 Relays
 Relay driver
 LCD module
 Fault switches

20. Power supply
 The power supply circuit consists of step down transformer which is 230v
step down to 12v.
 In this circuit 4diodes are used to form bridge rectifier which delivers
pulsating dc voltage and then fed to capacitor filter.
 The output voltage from rectifier is fed to filter to eliminate any A.C.
components present even after rectification.
 The filtered DC voltage is given to regulator to produce 5V constant DC
voltage.

21. VOLTAGE REGULATOR
POWER SUPPLY

22. Arduino UNO (Atmega 328P)
 The Arduino Uno is an open-source microcontroller board based on
the Microchip ATmega328P microcontroller and developed
by Arduino.cc. The board is equipped with sets of digital and
analog input/output (I/O) pins that may be interfaced to various expansion
boards (shields) and other circuits.
 The Atmega is 8-bit AVR RISC-based microcontroller combines
32 KB ISP flash memory with read-while-write capabilities,
1 KB EEPROM, 2 KB SRAM, 23 general purpose I/O lines, 32 general
purpose working registers, three flexible timer/counters with compare
modes, internal and external interrupts, serial programmable etc.

23. Arduino Uno board

24. ATmega328P in 32-pin thin quad flat pack

25. Relays
 Relay is sensing device which senses the fault and sends a trip signal to
circuit breaker to isolate the faulty section.
 A relay is an automatic device by means of which an electrical circuit is
indirectly controlled and is governed by change in the same or another
electrical circuit.
Relay circuit diagram 5v 2 Channel Relay
module

26. Relay driver
 IC Driver Circuit is used to boost or amplify signals from microcontrollers
to control power switches, relays.
 Driver circuits take functions that include isolating the control circuit and
the power circuit, detecting malfunctions.
 In this project, ULN2003 is used as the relay driver circuit. It is an
integrated circuit which functions as the relay driver and boosts up the
supply going to the relay.

27. Circuit diagram of
Relays and ULN2003

28. LCD module
 The term LCD stands for liquid crystal display. It is one kind of electronic
display module used in an extensive range of applications like various
circuits & devices like mobile phones, calculators, computers, TV sets, etc.
 These displays are mainly preferred for multi-segment light-emitting
diodes and seven segments. The main benefits of using this module are
inexpensive; simply programmable, animations, and there are no
limitations for displaying custom characters, special and even animations,
etc.
 It is used to display the status of the lines, type of fault and location of fault

29. Pin Configuration of LCD 16X2

30. Fault switches
 Fault switches are used to create the fault in the line.
 These creates oc and sc faults.
 As length and resistance are directly proportional to each other, we are
using the resistors to calculate the distance based on the resistance of the
fault current through the line.

31. arrangement of Fault switches in two lines

32. PROGRAM (C++)

33. WORKING
voltage is fed to the Arduino kit. A program was written if any fault occur
in the cable, then it will divert working of the system. Otherwise the system
works as usually. The Arduino kit has microcontroller which is used to store the
program. We uploaded the program in the kit. In the resistor circuit the resistors
are connected in series which is used as an underground cable and is useful to
detect the short circuit fault. This project uses a standard concept of Ohms law,
i.e., when a low DC voltage is applied at the feeder end through series resistor
then the current would vary depending upon the location of the fault in the
cable. In case of a short circuit (line to ground), the voltage across the series
resistors changes which is then fed to an ADC, to develop a precise digital data
that gets displayed on the LCD.

34. ADVANTAGES
 Detect faults in underground cables.
 Low cost
 Less complexity
 Less maintenance
 Applicable to long distance
 Less maintenance
 It has higher efficiency
 Less fault occur in underground cable
 This method is applicable to all types of cable ranging from 1kv to 500kv
 It can detect other types of cable fault such as Short Circuit fault, cable
cuts, Resistive fault, Sheath faults, Water trees, Partial discharges.

35. RESULT

36. CONCLUSION
It is not easy to spot the faults in underground cables. By using
Arduino controller we can find out accurate location of different faults. In
this project we detect both short circuit fault and open circuit fault, but for
open circuit fault we assume the fault locations. To avoid this assumption
we have to work some more on this model. If there is any fault in any of
the two line of underground cable then this detector is capable of
detecting the short circuit fault within the range of 4 km. When the fault
switches are operated to fault condition then the phase corresponding to
that particular switch is considered as the faulty phase. So the faulty
section can easily be located.

37. FUTURE SCOPE
In this project we detect the exact location of short circuit fault in the
underground cable from feeder end by using Arduino. In future, this
project can be implemented to calculate the impedance by using a
capacitor in an AC circuit and thus measure the open circuit fault.

38. FOLLOW ME ON
Engineeringsparkdna @ Instagram
Engineering Spark @YouTube
Engineeringsparkdna.blogspot.com @ Blogger
Doddi Nagasai @ LinkedIn
Engineeringsparkdna @ Pinterest
THANK
YOU