Information dependent data transmission for pilot protective relays
AssigneeABB AB
InventorsThomas M. LoCasale, Joel A. B. Elston, Ismail I. Jouny
Life of this patent
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Abstract
Waveform information is transmitted from the ends of a protection zone by first compressing the information using a lossy compression technique such as wavelets and then compressing the lossy compressed waveform information using a loss-less compression technique such as the Burrows-Wheeler transform. Status information is transmitted from the ends of the protection zone by compressing that information using the loss-less technique. The time for transmission can be less than, equal to or greater than the time for one cycle of the power line frequency.
Claims24
In an electrical transmission system having at least one pilot protective relay at a first location and at least one pilot protective relay at a second location separated from said first location, a method for transmitting waveform information from said first location to said second location and from said second location to said first location, said method comprising:
- a) compressing said waveform information at said first and said second locations using a lossy compression technique;
- and
- b) compressing said lossy compressed waveform information at said first and second locations using a loss-less compression technique.
In an electrical transmission system having at least one pilot protective relay at a first location and at least one pilot protective relay at a second location separated from said first location, each of said at least one pilot protective relays having waveform information associated therewith, a method comprising:
- a) compressing said associated waveform information at said at least one pilot protective relay at said first location and at said at least one pilot protective relay at said second location;
- and
- b) transmitting said compressed associated waveform information from said at least one pilot protective relay at said first location to said at least one pilot protective relay at said second location and from said at least one pilot protective relay at said second location to said at least one pilot protective relay at said first location.
An electrical transmission system comprising:
- (a) a pilot protective relay at a first location on said system;
- (b) a pilot protective relay at a second location on said system;
- said pilot protective relay at said first location transmitting waveform information from said first location to said second location and said pilot protective relay at said second location transmitting waveform information from said second location to said first location;
- (c) means for lossy compressing said waveform information at said first and second location;
- and
- (d) means for loss-less compressing said lossy compressed waveform information at said first and second locations.
Dependencies are inferred from the claim text.