Differential protection method for producing a fault signal characteristic of a fault
First Claim
1. A method for producing a fault signal characteristic of a fault current in an electrical conductor, the electrical conductor having at least two conductor ends each of which is connected to a respective charge measurement device, comprising:
- measuring charge measurement values using the respective charge measurement devices, the charge measurement values indicating an amount of charge which has flowed through the respective conductor end during a predetermined measurement duration;
forming an overall charge measurement value by addition of the respective charge measurement values, taking account of a direction of the charge flow;
weighting a charge measurement value with an individual measurement tolerance of the respective charge measurement device to form a respective measurement error for each of the charge measurement devices; and
producing the fault signal if the magnitude of the overall charge measurement value exceeds a threshold value, which is formed as a function of a sum of the respective measurement errors.
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Abstract
The invention relates to a method for generating an error signal which characterizes a fault current in an electrical conductor provided with two conductor ends and having charge measuring devices which are connected to each other by data lines. At least one device is attached to each end of the conductor. In the invention, charge measuring values are determined using charge measuring devices. The measured charge values take into account the direction of the charge flow and a total measured charge value is formed by addition. The error signal is generated when the total measured charge value exceeds a certain threshold value. In order to be able to detect errors in a more sensitive manner than had previously been possible, the threshold value is formed by taking into account the individual measuring tolerance of the individual charge measuring devices.
6 Citations
6 Claims
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1. A method for producing a fault signal characteristic of a fault current in an electrical conductor, the electrical conductor having at least two conductor ends each of which is connected to a respective charge measurement device, comprising:
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measuring charge measurement values using the respective charge measurement devices, the charge measurement values indicating an amount of charge which has flowed through the respective conductor end during a predetermined measurement duration;
forming an overall charge measurement value by addition of the respective charge measurement values, taking account of a direction of the charge flow;
weighting a charge measurement value with an individual measurement tolerance of the respective charge measurement device to form a respective measurement error for each of the charge measurement devices; and
producing the fault signal if the magnitude of the overall charge measurement value exceeds a threshold value, which is formed as a function of a sum of the respective measurement errors. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification