Differential protective method to generate an error signal characteristic of a fault current
First Claim
1. A method for generating an error signal that characterizes a fault current in an electric conductor which has an alternating current, comprising:
- measuring measured charge values that specify a charge quantity flowing through a respective conductor end during a prescribed measuring period;
forming a total measured charge value by addition using the measured charge values taking account of the direction of the flow of charge; and
generating the error signal when the total measured charge value exceeds an absolute threshold value set as a function of the accuracy of the respective charge measuring devices, wherein the measurement of the measured charge values is carried out in a time-synchronized fashion and is repeated regularly such that the time interval between two sequential measurements is smaller in each case than the prescribed measuring period.
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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 inventive method, charge measuring values are determined using charge measuring devices. The measured charge values take into account the direction of the charge flow 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. According to the invention, the measured charge values are determined synchronously and determined repeatedly at regular intervals in such a way that the time interval between each sequential determination is smaller than the predefined measuring period.
5 Citations
8 Claims
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1. A method for generating an error signal that characterizes a fault current in an electric conductor which has an alternating current, comprising:
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measuring measured charge values that specify a charge quantity flowing through a respective conductor end during a prescribed measuring period;
forming a total measured charge value by addition using the measured charge values taking account of the direction of the flow of charge; and
generating the error signal when the total measured charge value exceeds an absolute threshold value set as a function of the accuracy of the respective charge measuring devices, wherein the measurement of the measured charge values is carried out in a time-synchronized fashion and is repeated regularly such that the time interval between two sequential measurements is smaller in each case than the prescribed measuring period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification