Breakpoint Diagnosis of the Substations Grounding Grid using Derivative Method

Executive Summary:                                   In a power substation the grounding grid

Project Title

Breakpoint Diagnosis of the Substations Grounding Grid using Derivative Method

Project Area of Specialization

Electrical/Electronic Engineering

Project Summary

Executive Summary:

                                  In a power substation the grounding grid is the component that is used for its protection as it is responsible for driving short circuit and lightning currents into the ground. So if any fault occurs in the grounding grid or it is broken, it can result in significant increase in the surface potential and ultimately loss to the power system and personnel working there. This project proposes a technique based on derivative method to diagnose breakpoints in grounding grid. Where there is a conductor placed, the derivative of magnetic flux density results in peak at conductor’s location. If the conductor is broken, the flow of current through it and surface magnetic field ceases, which can be noted by the absence of peak at the conductor’s location. Furthermore, it will be proposing automation in finding the derivative of the surface magnetic flux density through using Arduino which will be connected to the flux meter. Arduino will receive different values from the flux meter which will further be used in the coding to find the derivative and provide the peak at the corresponding conductor’s location if it is not broken.

Project Objectives

Objectives:

                  The grounding grid is the main part in the safety of the whole grid system. If it becomes faulty or it is broken at any place it can result in significant rise in the surface potential which can cause serious damage to the grid system and to the operators as well. The grounding grid is made of metals and is buried inside the soil so with the passage of time it breaks at some locations. As it is buried inside the ground, it becomes difficult to know about the condition of the grid buried underneath. A method should be used to diagnose whether the grounding grid is faulty or not. The method which is proposed here is very much efficient and contains automation in it to find the condition of the grounding grid. The method involves the derivatives of the magnetic flux density which will be produced by the currents passing through the conductors and it will result in the form of peaks at the corresponding conductor’s position.

Project Implementation Method

Methodology:

                       In the method proposed here, current will be passed through the mesh of conductors, with the passage of the current magnetic feild will form around the conductors, which will be calculated with the help of magnetic flux meter. Flux meter will be placed on the Line Follower Robot which will follow the whole path of the conductor mesh. Flux meter will be further connected to the Arduino. In arduino, derivative would be taken with the help of the coding and it will be displayed in the form of peaks in the graph which will indicate the presence of conductors at that place and if peak is not formed it will indicate that the mesh is faulty or broken.

GROUNDING CONDUCTOR STATUS INVESTIGATION: A grounding conductor of infinite length stationed along y-axis is illustrated in Fig. 1. This conductor is buried at depth h in a homogeneous soil of permeability µ and carries current I. At the point P on the ground surface, the magnetic flux density according to Ampere’s law that surrounds the conductor is B?. Mathematically B? is expressed as:

B?=?I2?Ra?                                                                      (1)

The R in (1) is the distance between the conductor and point P. Expressing B? in terms of Cartesian coordinates is given as:

Bx+Bz=?I2?Rcos?ax-sin?az                                              (2)

Bx=?I2?hx2+h2ax                                                               (3)

Bz=-?I2?xx2+h2az                                                              (4)

In x-direction the 1st order gradient modulus of (3) and 2nd order gradient modulus of (4) is presented as:

Bx''=?Ih?×3x2-h2x2+h23ax                                                 (5)

Bz'=?I?×x2-h2x2+h22az                                                      (6)

Analyzing (5) and (6), Bx'' and Bz' are maximum at x=0m that resembles the location of the conductor below the earth surface.

The burial depth of the conductor for the case of Bx  and Bz is expressed as:

h?Lx2                                                                                  (7)

h?0.5774Lz1                                                                       (8)

The Lx2 and Lz1  are the distances between the main peak and side peak of Bx  and  Bz . According to (5) and (6), employing the limit at x=0 results in current I that is expressed as:

I=limx?0Bx''?h3?                                                               (9)

I=limz?0Bz'2?h2?                                                             (10)

For the status diagnosis of the grounding grid, the method proposed in the project will include onl

Figure 2: Magnetic flux density B? produced from an infinite length grounding conductor carrying current I. This conductor is stationed along y-axis and buried at depth h below the earth surface.

Benefits of the Project

Benefits of the Project:

1. Project will be helpful in status diagnosis of grounding grid.
2. The diagnosis will be done without excavation or without reaching directly to the grounding grid.
3. The project will include automation in it. Different values of magnetic feild will be taken by the magnetic flux meter, which will be provided to the arduino and with the help of coding the derivative would be taken automatically and it will be displayed in the form of peaks on display screen. 
4. The Hazards to the substation will be minimized or eliminated by keeping a check on the substations grounding grid.
5.  The power loss in result of increase of surface potential can be minimized or eliminated which occurs due to the faulty grounding grid.
6. The lives of operators working in the substation can be endangered by the lightening and short circuit currents which can cause surges in the substation, which is basically due to faulty grounding grid. By keeping a check on the grounding grid's condition, the project can help in providing safety to the operators working there.

Technical Details of Final Deliverable

In this project the diagnosis of grounding grid will be done with the help of breakpoint analysis. Moreover it will be providing automation in providing the results. The sensor will be calculating the magnetic field having some value which will be provided to the Arduino, which through coding will take derivative every time it will be given a certain value and it will display it with a graph. As a result it will provide us with the information whether the grounding grid is faulty or not.

Final Deliverable of the Project

HW/SW integrated system

Core Industry

Energy

Other Industries

Education , Health , Security

Core Technology

Wearables and Implantables

Other Technologies

Others

Sustainable Development Goals

Good Health and Well-Being for People, Industry, Innovation and Infrastructure, Sustainable Cities and Communities

Required Resources

If you need this project, please contact me on contact@adikhanofficial.com