SU1413562A1 - Method and apparatus for measuring the distance to shorting point in power transmission line - Google Patents

Abstract

The invention relates to electrical measuring equipment and can be used to determine the distance from a short circuit to a power line. The purpose of the invention, the increase in the accuracy of determining the distance to a short circuit on a power transmission line, is achieved by compensating for the disturbing influence of the harmonic component of the noise acting on the high voltage power transmission line. The device implementing the method consists of two identical channels — a voltage channel and a current channel, each of which contains an input unit 1, an analog-digital converter 2, a memory unit 3, a multiplier 4, an accumulator adder 5, a fixation unit 6, a unit 7 calculating the Fourier coefficients, the effective value calculating unit 8, the pulse generator 9, the pulse counter 10 and the first and second permanent memory units 11 and 12. The calculation to the short circuit location is performed according to the method and formulas given in the description of the invention. 2 sec. f-ly, 1 ill. L

Description

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The invention relates to electrical measuring technology and can be used to determine the distance to a short circuit on an electric power line.

The aim of the invention is to improve the accuracy of determining the distance to a short circuit on a power line by compensating for the interfering influence of the harmonic component of the noise acting on the high voltage line.

 The drawing shows a diagram of the device that implements the method of determining the distance to the short circuit on the power line.

The method is based on the analysis of an emergency signal, which is an additive mixture of a harmonic signal of known frequency f and total interference, includes converting the signal into signals y, (t) and) voltage and current in the transmission line, respectively, forming two auxiliary signals Cf; (t) as M, (t) cos2rfot and C (j (t) 3in2 irfQt), determining the effective values of the voltage and current of the harmonic component of the alarm signal, the values of which judge the distance to the short circuit, at the time of the occurrence of the alarm form a p-2 auxiliary signal Cp; (t) (), non-orthogonal to Cf, (t) and cpj (t), from each converted signal y, (t) and YjCt) using n auxiliary signals cp; (t ) form n signals

of the form tp; (t) .y (t), (, 2n),

each of which is an amplified transformed alarm signal, the received signals are integrated at a given time interval, the values of C; are recorded; the integrated Fourier coefficients a and b of the harmonic component are calculated using the integrated signals by the formulas

(one)

a C; d ;; Bc; 1 ;,

1 C1

where d- and 1; - pre-calculated

quantities

and using the Fourier coefficients, calculate the effective values of the harmonic components of the signals y, (t) and y (t), the values of which are determined by calculation by the distance to the short circuit.

The device for determining the response to the fault location consists of two identical voltage and current channels, respectively. Each channel contains an input unit I, an analog-to-digital converter (ADC) 2, a memory unit 3, a multiplier 4, an accumulator 5, a unit 6 fixings, block 7 for calculating Fourier coefficients, block 8 for calculating the effective value, generator of 9 pulses (GI), counter of 10 pulses (MFR), first 11 and second 12 blocks of permanent memory.

At the same time, from one of the ends of the transmission line is connected to the input of voltage and current channels, where the channel inputs are the inputs of the input blocks 1 of each channel, which in each channel the first output is connected to the first input of the ADC 2, and the second output to the input GI 9, the output of which is connected to the second input of AShCH1 2 and the input of the MF 10, the output of the A / D converter 2 is connected to the first input of the memory block 3, the second input of which is connected to the first output of the MF 10, the output of the memory block 3 is connected to the first input of the multiplier 4 whose second and third inputs are connected to the output of the first block of the fixed memory I1 and the second output of the RMS IO, respectively, the output of the multiplier 4 is connected to the input of the accumulating adder 5, connected in series with the fixing block 6, the output of which is connected to the first input of the Fourier coefficient calculator 7, the second input of which is With the output of the second constant memory unit 12, the output of the Fourier coefficient calculating unit 7 is connected to the input of the effective value calculating unit 8, the output of which is the output of each of the current or voltage channels.

The device works as follows.

In the initial state, CI 9 does not form a pulse sequence of an MF. 10 is set to zero, operation of multiplier 4 is prohibited. At the channel output, the harmonic component value is equal to iul.

When the alarm signal arrives at the input of the alarm device, the signal y (t) from the first output of the input unit 1 is fed to the signal input of the ADC 2. At the same time at the time of the occurrence of the alarm 311413562

signal at the second output of the input-4. Samples y () of the signal from the first block 1 appears controlling the output of the memory block 3 is received on the pulse enabling the GUI 9. It is the first input of the multiplier 4, using pulses From the output of the GI 9, the following operations are carried out: a smart-clock input of the A / D converter 2, determining their moments by the instantaneous values of time t (, 2, ..., N) of the discrete signals c and quantizing instant sign; (C). A set of auxiliary signals y (tn) alarm. Cheats defined in advance. Therefore, the pre-instantaneous values from the output of the A / D converter 2 Yury calculated their instantaneous values are recorded in memory block 3. The values are entered in block 11 of a permanently registered sample set by the memory memory, from the output of which they are SCID 10. After filling in block 3, they are fed to the second input of multiplier 4. Replace with N alarm samples, From the output of multiplier 4 removed n at the output of the transfer of the MSS 10 forms 15 numerical sequences of the following, with a pulse permitting the operation of the smart type:

Cf, (t,) y (t,), cf, (t2) y (t5,), ..., cf, (tK) y (t); tftCt; ) y (t,), cfj (tj) y (t), ..., t CtJyCt);

tpo ((t |)) y (t2), ..., 4 n (tM) y (tv)

Claims (2)

Each of the n numerical sequences; the calculation of the distance to the fault location on the binaries (2) is integrated into the transmission accumulator, the leading adder 5. After accumulating N results of multiplications, each Formula of the Invention from the sequences produces n values C; : 30 I. Method for determining distance With 21f -Ct Wft) (3) ° short circuit locations on line 1., the transmission, consisting in that which are memorized in block 6 fixes, analyze the alarm, predictions. The volume N of the sample to be processed is the additive mixture specified by the SCH 10 block when reading the dc harmonic signal of the known frequency data from block 3 of the memory.tot f and total interference, converting C values ;, which contain the alarm signal into the signal) the parameters of the harmonic signal and y (t) voltage and current of the corresponding x (t) and the total interference x (t), obviously, form two auxiliary ones. It is necessary to obtain information about the effect of the 40 signal in the form of cf, (t) cos27- f t and the effective value of the signal x (t). For C (j (t) sin2 irf t t), the coefficient values of the voltage and current of the Fourier harmonics a and b are first calculated in block 7 of the calculation of the emergency Fourier signal coefficients to the formulas of the according to the values of which is judged  J. and z S r.H- 45 the distance to the short circuit 11 and. ° 1 (i   - ff, none, different by n h f B c i b. TC 1-. What, in order to ensure accuracy and;, 1 i.i invoice compensation simultaneously with apevalues d; and 1; the computed 1-pre-periodic other components are sum- mated and stored in block 12 of the constant marginal disturbance at the moment of occurrence mi ti The calculated coefficients of the emergency signal additionally form Fourier in accordance with the pressure of the p-2 auxiliary signals I g. G Cp; (t) (), non-orthogonal on from AJ "-: ;-( 5) to .Cf, (t) and q (t), from each l / 255 converted signal y, (t) and in each channel, the effectivey (t) are calculated using n auxiliary the values of U, -, and ") in blocks 8 of the computational signals Cp; () form n signals laziness effective value. On the main-type of c); (t) -y (t) J, (, 2,3 ,, .., n), All values obtained are produced each of which is amplified (2) 5 to the converted alarm signal, the received signals are integrated over a given time interval and fix the values of C, the integrated signals, calculate the Fourier coefficients a and b of the harmonic component by the formulas a- Cid ;; b-ZlC; (1-1 Where. d and 1; - pre-calculated quantities and using the Fourier coefficients, calculate the effective values of the harmonic components of the signals y, (t) and y (t), where fj, is the harmonic signal of known frequency; t is the current time 2. A device for determining the distance to the short circuit on the power line, consisting of two identical channels for determining the effective values of voltage and current, respectively, whose inputs are combined and connected to the terminal for connecting the monitored line, and the outputs are the outputs of the device, each channel contains an input unit, whose input is a channel input, an analog-to-digital converter, a memory unit, and a pulse counter, which, in order to improve accuracy, each al introduced 26 pulse generator, first and second constant memory blocks, multiplier, accumulator, fixing unit, Fourier coefficients calculator and effective value calculator, whose output is the channel output, the first output of the input block connected to the first input of the analog-digital converter, and the second output with the input of the pulse generator, the output of which is connected to the second input of the analog-digital converter and the input pulse counter, the output of the analog-digital converter is connected to the first input of the memory unit, the second input of which is connected to the first output of the pulse counter, the output the memory unit is connected to the first input of the multiplier, the second and third inputs of which are connected to the output of the first permanent memory unit and the second output of the pulse counter, respectively, the output of the multiplier is connected to the input of the accumulating adder, serially connected to the fixation unit, whose output is connected to the first the input of the Fourier coefficients calculation unit, the second input of which is connected to the output of the second constant memory unit, the output of the Fourier coefficients calculation unit is connected to the input of the calculation unit effect vnogo value. I