Abstract: A method for determining an adjustment value for an electrical protection device wherein, upon occurrence of a ground short circuit, first current indicator measured values and first voltage indicator measured values are captured by a first measurement device at a first end of a segment of an electrical power supply line, and second current indicator measured values and second voltage indicator measured values are captured by a second measurement device at a second end of the segment of an electrical power supply line. In order to design a method of this type such that an adjustment value for a ground impedance can be determined in a relatively simple fashion.

Abstract: A differential protection system has a differential protection device at each end of a line section of an electrical power transmission line, such that it can selectively identify and safely disconnect even high-impedance faults on the monitored line section.

Abstract: A method for determining an adjustment value for an electrical protection device wherein, upon occurrence of a ground short circuit, first current indicator measured values and first voltage indicator measured values are captured by a first measurement device at a first end of a segment of an electrical power supply line, and second current indicator measured values and second voltage indicator measured values are captured by a second measurement device at a second end of the segment of an electrical power supply line. In order to design a method of this type such that an adjustment value for a ground impedance can be determined in a relatively simple fashion.

Abstract: A differential protection system has a differential protection device at each end of a line section of an electrical power transmission line, such that it can selectively identify and safely disconnect even high-impedance faults on the monitored line section.

Abstract: A method of detecting a fault in a monitored section of an electric line. A release signal and a direction signal are generated, in the event of a fault, by a measuring unit fitted at each end of every section of the line. The direction signal is transmitted via a low-transmission-capacity line from one measuring unit to another measuring unit. Each measuring unit produces, after generating the release signal, intermediate parameters which are suitable for calculating the location of the fault. The intermediate parameters are transmitted via the data-transmission line to the other measuring unit in the section where, in each case, a value is obtained indicating the location of the fault.

Abstract: A method of determining the fundamental component and the harmonics (I′(&ohgr;)) of a measured electric quantity (M) is described, where the measured quantity (M) is processed by an analog signal processing circuit (15), the processed measured quantity is sampled and subject to an analog-digital conversion with a subsequent discrete Fourier transform (DFT).

Abstract: The present invention relates to a process for determining harmonic oscillations of a fundamental component of an electrical signal, wherein the signal is sampled with a sampling frequency corresponding to a multiple of the fundamental component's frequency. The sampled values of the signal are subjected, after analog-to-digital conversion, to a discrete Fourier transformation to determine the harmonic oscillations. The sampling is performed with a non-integer multiple of the frequency of the fundamental component and the discrete Fourier transformation is performed while the frequency resolution is increased over several periods of the fundamental component to determine the harmonic oscillations.

Abstract: A digital process for determining the effective value of a periodic electric test signal is provided, where the test signal is sampled during a sampling interval that differs in duration from the period of the test signal, and after performing an analog-digital conversion of the samples, they are squared, added up and averaged. The square root of the resulting average is calculated. To be able to determine the effective value rapidly and with a high accuracy according to this invention with a sampling interval that corresponds to two periods of the electric test signal with an odd numbered M of samplings with N samples that fall in one period of the test signal, the values up to and including the Nth sample are squared and added up. To this is added a correction factor that corresponds to half of the square of a subtotal formed from one-quarter of the Nth sample and three-quarters of the (N+1)th sample, where N=(M−1)/2. Then the average is calculated over the number M/2.

Abstract: Impedance protection method for detecting short-circuits on a monitored section of an electrical power supply line in which impedance values formed by current and voltage during a short-circuit in order to extract a tripping signal are checked to see whether they lie within a specific tripping characteristic. A relatively small first tripping characteristic in relation to the monitored section is used, and impedance values first determined are compared to this first tripping characteristic to see whether they lie inside or outside this tripping characteristic; the tripping signal is generated if the impedance values lie within the characteristic and, if not, the system switches to a maximum tripping characteristic corresponding to the monitored section. Impedance values following the impedance values first determined are checked to see whether they lie within the maximum tripping characteristic and, if they do, the tripping signal is generated.

Abstract: The present invention relates to a process for determining harmonic oscillations of a fundamental component of an electrical signal, wherein the signal is sampled with a sampling frequency corresponding to a multiple of the fundamental component's frequency. The sampled values of the signal are subjected, after analog-to-digital conversion, to a discrete Fourier transformation to determine the harmonic oscillations. The sampling is performed with a non-integer multiple of the frequency of the fundamental component and the discrete Fourier transformation is performed while the frequency resolution is increased over several periods of the fundamental component to determine the harmonic oscillations.

Abstract: A process for obtaining a measured value from an electric signal with a predetermined rated frequency, wherein the electric signal is scanned with a scanning frequency that is N times the rated frequency. After analog-to-digital conversion, the measured value is determined in an analyzer. In order to determine the measured value with a comparatively high accuracy, a measured value (f.sub.Nist) is generated by means of a frequency meter (8). The measured value (f.sub.Nist) is multiplied by a factor N yielding a derived measured value (f.sub.Asoll). An analog-to-digital converter (1) is clocked with a scanning frequency (f.sub.A) that corresponds to the derived measured value (f.sub.Asoll).

Abstract: In order to permit rapid, high-resolution measurement of the frequency of an electrical signal using a digital device, the electrical signal is fed to two linear-phase non-recursive digital filters (3, 20) with symmetrically distributed filter coefficients (a(n), t(n)), one of which is developed as an all-pass filter (3) and the other as a low-pass filter (20). Following the all-pass filter (3) there is a circuit unit (4) in which a logic signal (r(.OMEGA.)) is formed by means of two transverse filters (5, 6) time-delay member (7, 9), multipliers (8, 10) and a difference former (11), said logic signal being dependent on the quantity frequency responses of the transverse filters (5, 6) and the square of the scanned values of the all-pass filter (3). A further logic signal (s(.OMEGA.)) is generated by a circuit device (21) which is designed in a manner corresponding to the circuit unit (4) and is arranged following the low-pass filter. By quotient formation of the logic signals (r(.OMEGA.)), s(.OMEGA.

Abstract: The present invention relates to a circuit for converting a plurality of analog electrical measurement signals into corresponding digital signals. To realize such a circuit with relatively few circuit elements, input-side antialiasing filters are linked on the output side to at least two multiplexers, which have at least two downstream sample-and-hold circuits connected to them. At least two analog-digital converters are linked on the input side to the output of a sample-and-hold circuit. An evaluation device is arranged downstream from the at least two analog-digital converters and acquires in one evaluation interval (0 through T1) digital values corresponding to several sampling values of an electrical signal, and produces the corresponding digital signal through mean value generation.