Underground Cable Fault Detection Schematic (1) (1)

Underground cable fault detection without GSM ABSTRACT The objective of this project is to determine the distance of underground cable fault from thebase station in kilometers and displayed over the internet. Underground cable system is a common practice followed in major urban areas. While a fault occurs for some reason, at that time the repairing process related to that particular cable is difficult due to exactunknown location of the fault in the cable. Proposed system is used to find out the exact location of the fault and to send data in graphical format to a dedicated website together with on board LCD display using a GSM module. The project uses the standardtheory of Ohms law, i.e., when a low DC voltage is applied at the feeder end through a series resistor(Cable lines),then the current would vary depending upon the locationof the fault in the cable as the resistance is proportional to the distance. In case there is a short circuit (Line to Ground), the voltage across series resistorschanges according to the resistance that changes with distance .This is then fed to an ADC to develop precise digital data which the programmed microcontrollerof the 8051 family displaysin kilometers. The project is assembled with a set of resistors representing the cable length in km and the fault creation is made by a set of switches at every known km to cross check the accuracy of the same. The fault occurring at a particular distance,therespective phase along with the distance is displayed on the LCD. The same information is alsosent to a dedicated website overinternet activated SIM with GSM, interfacedto the microcontroller. Furthermore, this project can be enhanced by using capacitor in an AC circuit to measure the impedance which can even locate the open circuited cable, unlike the short circuited fault that uses only resistors in DC circuit as followed in the above proposed project.

2. SCHEMATIC DIAGRAM

FIG 6: SCHEMATIC DIAGRAM

CONNECTIONS

The output of the power supply which is 5v is given to the 40rth pin of microcontroller and GND is connected to its 20th pin. Port 1.0 to 1.3 of microcontroller are given to 18 to 15 pin of ADC0804. Relay’s 1,2,&3 are given to pins 1B,2B&3B of ULN2003A and port0.0 to 0.2 of microcontroller. Port 3.0 to 3.5 of microcontroller are given to pin 2,3,5 of ADC0804. Pin’s 16,15,14 of ULN2003A are given to relay’s RL1,RL2,RL3 which drives set of resistor’s (R17,R16,R15,R14), (R21,R20,R19,R18) and (R25,R24,R23,R22).

WORKING 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.

OPERATING PROCEDURE

While any of the 12switches are operated they impose conditions like LG, LL, 3L fault as per the switch operation. The program while executed continuously scan’s by operating the 3relays in sequence of 1sec interval. Thus any NO point while driven to GND through the common contact point of the relay develops a current flow through R1, R10 & any other switch depending on the created fault. Thus the voltage drop at the ADC pin varies depending on the current flow which is inversely proportional to the resistance value representing the length of cable in kilometres. This varying voltage passes through the ADC to develop a 8 bit data to the microcontroller port1 that while executed display’s an output in the LCD display the fault

occurring km. In a fault situation it display’s R=3km if the 3km’s switch is made ON. Accordingly all other faults are indicated.

7. LAYOUT DIAGRAM

RESISTORS 1

R1

330R

22

R2-R23

1K

1

R24

2.2K

3

R25-R27

10K

CAPACITORS 1

C1

470UF

2

C2,C3

10UF

2

C4,C5

33PF

1

C6

56PF

1

U1

7805

1

U2

AT89S52

1

U3

ADC0804

1

U4

ULN2003A

IC'S

IC BASE 1

40-PIN

1

20-PIN

1

16-PIN

DIODES 4

D1-D4

IN4007

Miscellaneous 1

X1

11.0592MHz CRYSTAL

1

RV1

1K POT

1

RV2

10K POT

4

LED1-LED4

LED-RED

3

RELAY1-RELAY3

12V

1

LCD

16X2

1

TRANSFORMER

0-12V

1

S1

PUSH BUTTON

12

S2-S13

TOGLE SWITCHES

1

FEMALE BURGE

16-PIN

1

MALE BURGE

16-PIN

1

MALE BURGE

2-PIN

1

FEMALE BURGE

2-PIN

1

HEAT SINK

3

PCB CONNECTORS

2-PIN

9.2 SOURCE CODE #include

#define LCDDATA P2 #define ADCDATA P1 #define MINIMUM 5

sbit BUSY = P2^7; sbit RS = P2^0; sbit RW = P2^1; sbit EN = P2^2;

sbit OE = P1^3; //RD pin sbit SC = P1^4;

// WR is active LOW pin

sbit EOC = P1^5; //INTR is active LOW pin

sbit RELAY1 = P1^0; sbit RELAY2 = P1^1; sbit RELAY3 = P1^2;

unsigned char Buff[3] = 0;

void ISR_T0() interrupt 1

{ TH0 = 0x4B; TL0 = 0xFF;

TF0 = 0; }

void Delay(unsigned int time) { unsigned int i = 0; for(i=0;i