GPS (Global Positioning System)

and

its application in protection scheme

Submitted by:

J Shanthan Balaji Reddy

(10QA1A0248)

OVER VIEW

INTRODUCTION

TRANSMISSIUON SYSTEM

FAULT LOCATION

TRAVELING WAVE FAULT THEORY

FAULT LOCATION USING GPS

ADVANTAGES

CONCLUSION

INTRODUCTION

A new technique for the protection of transmission

systems.

Relays are installed at each bus bar in a

transmission network.

Relay contains a fault detection system together

with a communication unit.

Relay determine the location of the fault.

TRANSMISSION SYSTEM

GENERATION TRANSMISSION DISTRIBUTION

LOCATION OF FAULT

Save time and resources for the electric utility

industry.

Determine “distance to fault” from a transmission

line end.

Aid in fast restoration of power.

Communication systems can retrieve fault

location information.

WHAT IS TRAVELING WAVE FAULT

LOCATION?

Faults on the power

transmission system cause

transients that propagate

along the transmission line

as waves.

These waves have a

propagation velocity &

characteristic impedance ,

travel from fault location

towards line ends

The location of faults is accomplished by precisely

time-tagging wave fronts as they cross a known

point typically in substations at line ends.

Fault location can then be obtained by multiplying

the wave velocity by the time difference in line ends.

TRAVELING WAVE FAULT LOCATION

THEORYTraveling wave fault locators make use of the transient signals

generated by the fault.

Unlike other fault location systems, the traveling wave fault

locator is unaffected by load conditions.

Precisely synchronized clocks are the key element in the

implementation of this fault location technique.

The required level of clock accuracy has only recently been

available at reasonable cost with the introduction of the Global

Positioning System.

BENEFITS OF TRAVELING WAVE FAULT

LOCATION

Early fault locators used radar.

Radar equipment is typically mobile or located

at substations and requires manual operation.

Traveling wave fault locators are becoming popular

where higher accuracy is important.

GPS-based sub microsecond timing system has proven

reliable in several utility traveling wave projects.

POSSIBLE CAUSES OF FAULT

FAULT LOCATION USING GPS

Global Positioning System (GPS)

is a satellite-based navigation

system made up of a network of 24

satellites placed into orbit.

Originally intended for military

applications

Allows precise determination of

location, velocity, direction and

time.

HOW GPS WORKS?

GPS satellites circle the earth

twice a day .

Transmit signal information to

earth.

Receivers take this information

and calculate the user's exact

location.

Accurate 3-D location require

four satellites.

OPERATION OF THE FAULT

LOCATION SYSTEM(FLS) USING GPS

A fault locator remote is coupled to

each end of line via CPT.

FL is synchronized to the common

timing standard of UTC from GPS.

Fault resulting produces

travelling waves(transients).

The FL remote time tag the

transient arrival times.

By knowing the line length

L and the time-of –arrival

difference (tb - ta ) distance

X can be calculated from

the FL equation:

X=[L-C(tb - ta )]/2

ta & tb are end A and

end B arrival time

c-velocity of light

ADVANTAGES

Protection of transmission line using GPS is

extremely accurate.

Economical.

Fast response.

Reliability & availability

CONCLUSION

Uses a dedicated fault detector to extract

transient signal and GPS system to time tag these signals.

Travelling time of the transient signal from the point of fault to

the adjacent substation is used to determine the fault position.

Proposed technique is able to offer a high accuracy

in fault location.

Unlike traditional protection schemes , this technique offers

a new concept in network protection.

REFERENCES

Zhiqian Q Bo Weller, Tom Lomas and Miles A, Redfern

“Positional Protection of Transmission system Using

global Positioning System” IEEE Trans. On Power

delivery, vol15 no 4 oct 2008

http://www.howstuffworks.com/gps

http://www.gisdevelopment.net/technology/gps