Underground Cable Fault Distance Locator : Circuit and Its Working

Till the last decades, a million miles of cables are threaded in the air across the country. But currently, it is laid in the underground, which is larger than an earlier method. Because, underground cables are not affected by any adverse weather conditions like pollution, heavy rainfall, snow, and storm, etc. But, when any problem occurs in cable, it is very difficult to find the exact location of the fault due to not knowing the exact location of the cable. Day by day, the world is becoming digitized so the project is proposed to find the location of the fault in a digital way. When the fault occurs, the process of repairing related to that particular cable is very difficult. The fault of the cable mainly occurs due to many reasons. They are: inconsistent, any defect, weakness of the cable, insulation failure, and breaking of the conductor. To overcome this problem, here is a project namely an underground cable fault distance locator, used to find the location of the fault for underground cable.


Underground Cable Fault Locator
Underground Cable Fault Locator

Underground Cable Fault Distance Locator

Before attempting to find underground cable faults on direct hidden primary cable, it is essential to know where the cable is situated and what direction it takes. If the fault occurs on the secondary cable, then knowing the exact route is even more critical. Since it is extremely difficult to find a cable fault without knowing where the cable is, it makes sense to master cable locating and tracking before start the fault locating process.

The success of fault tracking and locating of an underground cable mainly depend on the skill, knowledge, and experience of that person. Although tracing of the cable can be an intricate job, it will very likely become even more complex as the more underground plant is installed. It is just as important to understand how the equipment works.

Types of Faults

A fault in a cable can be classified into different types such as

Open Circuit Fault

This type of fault is better than short circuit fault, because when they open circuit fault occurs, then the flow of current through an underground cable becomes zero. This fault can be occurred by a disruption in the conducting path. Such faults occur when one or more phase conductors break.

Short Circuit Fault

Short circuit fault can be divided into two types, namely symmetrical and unsymmetrical faults

  • In symmetrical fault, three phases are short-circuited in this type of fault. This type of fault is also called a three-phase fault due to this reason.
  • In unsymmetrical fault, the magnitude of the current is not equal and displaced by 120 degrees.

Different Methods of Fault Location

Free location methods can be classified into different types that are discussed below.

Underground Cable Fault Localization
Underground Cable Fault Localization

Online Method

The online method uses and processes the sampled current and voltages to determine the fault points. This method for underground cables is less than the above lines.

Offline Method

This method uses a special instrument to test out the service of cable in the field. The offline method is classified into two methods such as the tracer method and the terminal method.

Tracer Method

In this method fault of the cable can be detected by walking on the cable lines.The fault location is denoted from the electromagnetic signal or audible signal. This method is used to find the fault location very accurately.

Terminal Method
The terminal method is used to detect the location of the fault in a cable from one end or both the ends without tracking. This method is used to find general areas of the fault to accelerate tracking on buried cable.

Underground Cable Fault Distance Locator Circuit

The main concept of this project is to find the distance of underground cable fault from the base station in kilometers. In many urban areas, cable fault is a common problem. When a fault occurs due to some reason, the process of fault tracking without knowing the location related to that particular cable is very difficult. The proposed system is designed to track the exact location of the fault occurred in the cable.

Underground Cable Fault Distance Locator Circuit
Underground Cable Fault Distance Locator Circuit

This project uses the Ohms Law concept, when a low voltage DC is applied to the feeder end through a series resistor, then the current would differ based on the location of fault occurred in the cable. In case is there any short circuit occurred from line to ground, then the voltage across series resistor alters accordingly, then it is fed to an analog to digital converter to develop exact data, which the pre-programmed 8051 microcontrollers will display in kilometers.

The proposed system is designed with a set of resistors to signifying the length of a cable in kilometers, and the fault creation is designed with a set of switches at every known kilometer (KM) to cross-check the exactness of the same. The fault happening at a specific distance and the particular phase is displayed on an LCD interfaced to the 8051 microcontrollers.

Underground Cable Fault Distance Locator Project Kit
Underground Cable Fault Distance Locator Project Kit

Thus, this is all about the underground cable fault distance locator. In the future, this project can be implemented to measure the impedance by using a capacitor in an AC circuit. We hope that you have got a better understanding of this concept, or online shop for electrical & electronic project kits please give your valuable suggestions by commenting in the comment section below. Here is a question for you, what are the types of faults?

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