Slide 1: PROTECTOIN OF TRANSMISSION
LINES USING GPS by:
EEE OVER VIEW : OVER VIEW INTRODUCTION
CAUSES OF FAULTS
GPS TECHNIQUE Slide 3: 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. INTRODUCTION LOCATION OF FAULT : 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. Slide 5: GENERATION TRANSMISSION DISTRIBUTION TRANSMISSION SYSTEM Slide 6: TRANSMISSION LINES Slide 7: WHAT IS TRAVELING WAVE
FAULT LOCATION? Faults on the power transmission system cause transients
that propagate along the transmission line as waves.
Fault location can then be obtained by multiplying
the wave velocity by the time difference in line ends. Slide 8: BENEFITS OF TRAVELING WAVE FAULT LOCATION Early fault locators used pulsed radar.
Radar equipment is typically mobile or located at substations and requires manual operation.
Impedance-based fault locators are a popular means of
transmission line fault locating.
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. Slide 9: TRAVELING WAVE FAULT LOCATION THEORY Traveling wave fault locators make use of the transient
signals generated by the fault.
Unlike impedance-based 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. Slide 10: The voltage and current at any point x obey the
partial differential Equations
Where L and C are the inductance and capacitance
of the line per unit length. Slide 11: POSSIBLE CAUSES OF FAULT Slide 14: WHAT IS 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. Slide 15: HOW GPS WOKS? 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. Slide 16: THE GPS SATELLITE SYSTEM 24 satellites that make up the GPS space segment
are orbiting the earth about 12,000 miles above us. Slide 17: WHAT’S THE SIGNAL? GPS satellites transmit two low power radio signals.
A GPS signal contains three different bits of information.
- a pseudorandom code,
- almanac data. Slide 18: HOW ACCURATE IS GPS? Today's GPS receivers are extremely accurate.
GPS receivers are accurate to within 15 meters on
Newer GPS receivers with WAAS
(Wide Area Augmentation System) capability can
Improve accuracy to less than three meters on average.
Increased accuracy to within an average of three to five
meters. Slide 19: SOURCES OF GPS SIGNAL ERRORS Ionosphere and troposphere delays.
Receiver clock errors.
Number of satellites visible.
Intentional degradation of the satellite signal. Slide 20: CONCLUSION Thus the use of GPS in protection of transmission systems is
beneficial in the respects like
-Value regarding programmatic goals