Device, system, and method for double-circuit transmission systems
AssigneeHitachi Energy Ltd
InventorsNeethu George, Od Naidu
Life of this patent
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Abstract
A device is provided that is suitable for use with a double-circuit power transmission system having a first line and a second line. The device comprises an interface to receive a current measurement for the second line. The device comprises at least one processing module operative to estimate a first zero-sequence current in the first line based on a second zero-sequence current, and determine an apparent impedance based on the estimated first zero-sequence current.
Claims15
A device for use with a double-circuit power transmission system having a first line and a second line, wherein the device is a protection device operative to perform a protection function based on the apparent impedance, and wherein the protection function is a distance protection function, the device comprising:
- an interface to receive a current measurement for the second line;
- and
- at least one processor operative to
- calculate a second zero-sequence current in the second line based on the current measurement,
- estimate a first zero-sequence current in the first line based on the second zero-sequence current, wherein the device is operative to multiply the second zero-sequence current by a multiplicative factor to estimate the first zero-sequence current, and wherein the multiplicative factor is dependent on a status of the first line and a transformer configuration of transformers at opposite terminals of both the first line and the second line,
- determine an apparent impedance based on the estimated first zero-sequence current, and
- trip a relay, circuit breaker, or switch as a function of the apparent impedance.
A method, comprising:
- estimating, by a device, a first zero-sequence current in a first line of a double-circuit transmission system, the first zero-sequence current being estimated based on multiplying a second zero-sequence current in a faulted second line of the double-circuit transmission system by a multiplicative factor to estimate the first zero-sequence current, wherein the multiplicative factor is dependent on a status of the first line and a transformer configuration of transformers at opposite terminals of both the first line and the second line;
- determining, by the device, an apparent impedance based on the estimated first zero-sequence current;
- and
- tripping, by the device, a relay, circuit breaker, or switch as a function of the apparent impedance.
Dependencies are inferred from the claim text.