Till the last decades, a million miles of cables are wound in the air across the country. But now it is placed in the underground, which is higher to an earlier method. Because, underground cables are not affected by any opposing weather condition like heavy rainfall, pollution, snow, and storm, etc. But, when any fault occurs in cable, it is very difficult to discover the exact place of the faulty due to not knowing the exact location of the cable. Currently, the world is becoming digitized so this project is proposed to find the fault cable location in a digital way. When the fault arises, the method of repairing connected to that specific cable is very difficult.
The cable fault mainly occurs due to several reasons. They are any defect, inconsistent, insulation failure, weakness of the cable, and breaking of the conductor. To overcome this difficulty, here is a solution, namely underground cable fault distance locator, helpful to discover the fault cable location in underground.
Currently, the world is becoming digitized so this project is proposed to find the fault cable location in a digital way. When the fault arises, the method of repairing connected to that specific cable is very difficult. The cable fault mainly occurs due to several reasons. They are any defect, inconsistent, insulation failure, weakness of the cable, and breaking of the conductor. To overcome this difficulty, here is a solution, namely underground cable fault distance locator, helpful to discover the fault cable location in underground.
What are Underground Cable Faults?
Underground cable faults are damaging to cables which result in a resistance in the cable. If permitted to continue, this can lead to a voltage breakdown. The different types of cable faults, which must first be categorized before they can be situated. The protection of the cable plays a vital role in this. While some cables like paper-impregnated are mainly susceptible to exterior chemical and thermal effects.
Underground Cable Fault Distance Locator
Before trying to discover underground cable faults on direct buried primary cable, it is crucial to know where the cable is located and what route it takes. If the error occurs on the secondary cable, then knowing the particular path is even more critical. Since it is very hard to find a faulty cable without knowing where the cable is, it makes sense to main cable finding and tracing before start the error finding process.
The underground cable fault locating and fault finding mainly depends upon the knowledge, experience and also the skill of the person. While finding the underground cable can be a complex job, it will become even more difficult as the more underground plant is fixed. It is just as significant to know how the gear works.
Different Types of Cable Faults
Cable faults are classified into two types, namely open circuit fault and short circuit fault.
Open Circuit Fault
The open circuit fault is better than another type of fault, because when this type of fault occurs, then the current flow through an underground cable becomes zero. The open circuit fault can be occurred by trouble in conducting path. Such faults arise when one or more phase conductors break.
Short Circuit Fault
Short circuit fault can be classified into two types, such as symmetrical fault and unsymmetrical fault. In symmetrical fault, 3-phases are short circuited because of this reason, it is also called as three phase fault. Whereas in unsymmetrical fault, the magnitude of the current is not equivalent and displaced by 120 degrees.
Different Methods of Fault Location
Fault location methods can be classified into four types namely, online method, offline method, tracer and terminal method.
This type of method uses & process the sampled voltage and current to control the fault points.
The offline method uses a separate instrument to test out service of cable in the field. This method is classified into two like tracer method and terminal method.
Tracer method can be used to find the fault of the cable by walking on the cable lines. Fault location is indicated by an audible signal or electromagnetic signal. This type of method is used to discover the fault location very exactly.
This type of method is used to notice the location of the cable fault from one end or both the ends without tracing. This type of method is very useful to find common areas of the fault to accelerate traced on buried cable.
Block Diagram of Underground Cable Fault Distance Locator
The main goal of this underground cable fault distance locator projects is to find the distance of faulty cable in underground. This system is a common practice followed in several urban areas.While fault occurs for any reason, at that time the repairing process for that particular cable in very difficult due to not knowing the exact location of the cable.
The proposed system is very useful in finding the faulted cable. The block diagram of the underground cable fault distance locator is shown below. The hardware and software requirements of this project include 8051 series Microcontroller, LCD, Crystal, ADC, Relays, Relay Driver IC, Transformer, Diodes, Voltage Regulator, Resistors, Capacitors, LEDs and Slide switches.
The 230V AC power supply is the first step down to 12V AC using a step-down transformer.This is then converted to the DC using a bridge rectifier.The AC ripples are filtered out by using a capacitor and given to the input pin of the voltage regulator 7805.At the output pin of this regulator, we get a constant 5V DC which is used for MC and other ICs in this project.
It is a smaller computer and it has on-chip RAM, ROM, I/O ports.The main features of microcontroller include the following.
- 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
Analog to Digital Converter
- 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.
The features of the ADC include the following
- Compatible with micro controllers, 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 a 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.
- A relay is an electrical\ functioned switch.
- The flow of current through the coil of the relay makes magnetic field which attracts a lever and changes of the switch contacts.
- The coil current can be on/off so relays have to switch locations and have double throw (changeover) switch contacts.
- These allow switching one circuit to a second circuit which can be entirely separate from the first.
- For instance, 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.
- MC ULN2003 relay driver IC is used to drive a relay through
Relay Driver ULN2003
- ULN is a Relay driver application
- This is a monolithic high voltage & high current Darlington transistor arrays.
- It comprises of 7-NPN Darlington pairs that feature high voltage o/ps with common-cathode clamp diode for inductive loads ON.
- The collector-current rating of a single Darlington pair is 500mA.
- The Darlington pairs may be paralleled for higher current capability
- The ULN works as an inverter.
- If the logic at i/p 1B is high, then the o/p at its corresponding pin 1C will be low.
Liquid Crystal Display (LCD)
- Most common LCDs connected to the microcontrollers are 16×2 and 20×2 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.
- 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.
- 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. 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 the compiler is a program that translates source code into object code.
This project uses the simple concept of “Ohms Law” microcontroller when a low DC voltage is applied to the feeder end of a series resistor, then the current would vary based on the fault location occurred in the cable.
In case is there any short circuit happened from LG (line to ground), then the voltage across series resistor varies accordingly, then it is fed to an ADC (analog to digital converter) to develop precise data, which the micro controller will display in kilometers.
This project is designed with a set of resistors to represent the length of a cable in kilometers, and the fault making is designed with a set of switches at each known kilometer (KM) to cross check the accuracy of the same. The fault occurring at an exact distance and the specific phase is shown on an LCD interfaced to the 8051 microcontrollers.
The advantages of an underground cable fault distance locator include the following.
- Maintenance is very less, fewer faults and higher efficiency.
- These instruments are applicable to all kinds of cables ranging from 1 kV to 500 kV, and all types of faults are
- These instruments are applicable to all kinds of cables ranging from 1 kV to 500 kV, and all types of faults are
- Short circuit faults
- Cable faults
- Resistive faults
- Intermittent faults
- Sheath faults
- Water trees
- Partial discharges
The disadvantages of an underground cable fault distance locator include the following. Cost, must consider the lifetime costs not just initially
- Cost must consider the lifetime costs not just initially
- The cost differential decreasing with time
- Cost of losses, maintenance, and repair
- Outage time, locate faults and repair
- Fault location instantaneous can have longer repair time.
From the above information finally, we can conclude that by using this project we detect the location of the fault in the underground cable from the base station in km with the help of the 8051 microcontrollers. For this, we use the concept of ‘ohms law’ so that the location of the fault can be detected. Furthermore, any doubts regarding his concept or to implement underground cable fault distance locator project please, give your valuable feedback by commenting in the comment section below. Here is a question for you, what are the applications of underground cable faults?