Method and arrangement for generating an error signal
First Claim
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1. A method for producing a fault signal identifying a location of a ground fault on a line between two line ends, which comprises the steps of:
- measuring a voltage and a current at each of the two line ends, with measured values being formed;
determining a harmonic component contained in one of a zero phase-sequence voltage and a zero phase-sequence current, as well as a decay time constant for each of the two line ends, using the measured values;
forming a magnitude and a phase of a harmonic vector measurement variable in each case using the harmonic component and the decay time constant for each of the two line ends, wherein a time reference point of the phase of the harmonic vector measurement variable relates to a time of the ground fault detection at a respective line end;
rotating the harmonic vector measurement variables formed in this way, starting from the respective line end, to a time in a past;
determining the time in the past and a location on the line at which rotated-back harmonic vector measurement variables have at least approximately a same magnitude and at least approximately a same phase, and the location on the line determined is regarded as the location of the ground fault; and
outputting the location with a fault signal.
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Abstract
A method generates an error signal indicating the location of a ground fault in a line between two line ends. A voltage and a current are measured at both ends of the line, establishing measured values, and the location of the ground fault is determined when or after a ground fault is detected. Accordingly, harmonic indicator variables are established and used for determining the location of the ground fault.
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Citations
16 Claims
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1. A method for producing a fault signal identifying a location of a ground fault on a line between two line ends, which comprises the steps of:
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measuring a voltage and a current at each of the two line ends, with measured values being formed; determining a harmonic component contained in one of a zero phase-sequence voltage and a zero phase-sequence current, as well as a decay time constant for each of the two line ends, using the measured values; forming a magnitude and a phase of a harmonic vector measurement variable in each case using the harmonic component and the decay time constant for each of the two line ends, wherein a time reference point of the phase of the harmonic vector measurement variable relates to a time of the ground fault detection at a respective line end; rotating the harmonic vector measurement variables formed in this way, starting from the respective line end, to a time in a past; determining the time in the past and a location on the line at which rotated-back harmonic vector measurement variables have at least approximately a same magnitude and at least approximately a same phase, and the location on the line determined is regarded as the location of the ground fault; and outputting the location with a fault signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A configuration for producing a fault signal that identifies a location of a ground fault on a line between a first and a second line end, the configuration comprising:
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a first measurement instrument at the first line end of the line for measuring a voltage and a current at the first line end resulting in measured values; a second measurement instrument at the second line end of the line for measuring a voltage and a current at the second line end resulting in measured values; and an evaluation device connected to said first and second measurement instruments and uses the measured values from said first and second measurement instruments, said evaluation device programmed to; determine a harmonic component contained in one of a zero phase-sequence voltage and a zero phase-sequence current, as well as a decay time constant for each of the first and second line ends, using the measured values; form a magnitude and a phase of a harmonic vector measurement variable in each case using the harmonic component and the decay time constant for each of the first and second line ends, wherein a time reference point of a phase of the harmonic vector measurement variable relates to a time of the ground fault detection at a respective line end; rotate the harmonic vector measurement variables formed in this way, starting from a respective line end, to a time in a past; determine the time in the past and a location on the line at which a rotated-back harmonic vector measurement variables have at least approximately a same magnitude and at least approximately a same phase, and the location on the line determined is regarded as the location of the ground fault; and output the location with a fault signal. - View Dependent Claims (12, 13, 14)
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15. A field device for connection to one line end of an electrical line and for identification of a ground fault on the line, the field device comprising:
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an evaluation device programmed to; determine a harmonic component contained in one of a zero phase-sequence voltage and a zero phase-sequence current, as well as a decay time constant for each of first and second line ends, using measured values; form a magnitude and phase of a harmonic vector measurement variable in each case using the harmonic component and the decay time constant for each the first and second line ends, wherein a time reference point of a phase of the harmonic vector measurement variable relates to a time of ground fault detection at a respective line end; rotate the harmonic vector measurement variables formed in this way, starting from the respective line end, to a time in a past; determine the time in the past and a location on the line at which a rotated-back harmonic vector measurement variables have at least approximately a same magnitude and at least approximately a same phase, and the location on the line determined is regarded as the location of the ground fault; and output the location with a fault signal; and a data connection for connection to another measurement instrument for receiving measured values which relate to another line end of the line. - View Dependent Claims (16)
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Specification