SU779936A1 - Method of locating short-circuiting in power transmission line with devices for longitudinal and transverse compensation and for adjusting - Google Patents

Description

(54) METHOD FOR DETERMINING A SHORT FOR ELECTRONIC BEFORE LONG AND NAST The invention relates to the field of electrical measuring equipment and mono. It can be used to create devices for detecting damage sites on power lines. A known method of determining the location of damage in the DC power lines is based on measuring the time interval between the phase-phase wave front and the phase-zero front, as well as the derivative of the initial voltage drop 1. The disadvantage of this method is low damage to ac power lines. The closest in technical essence is a method based on the measurement of modal forward and reverse electromagnetic field waves shifted relative to each other by a double time g of travel from the measurement point to the short circuit point (2. The disadvantage of this method is the inability to determine the location of damage in the line x electrical transmissions with elements of adjustment and compensation, i.e., all along the line. OTHER PLACES IN A LINE WITH REDUCED COMPENSATION DEVICES I., The aim of the invention is to provide determining the location of the short cable over the entire length of the transmission line.To achieve this goal in the method of determining the location of short circuits in the power line with devices of longitudinal and transverse compensation and tuning, based on the measurement of the modal forward and reverse waves of the electromagnetic field shifted each relative to a friend for a double travel time from the point of measurement to the point of short circuit, form signals that are multiples of the integrals of the measured modal forward and backward waves for the given time interval, and the multiplicity of integration is set according to the number of kcwneHca- devices. and settings in the power line, shift signals that are multiples of the integrals from modal. backwave relative to signals that are multiples of the integrals from modal forward waves, for a double travel time from the measurement point to the short circuit, sum up the same modal forward and backward waves and the same multiples of integrals

t modal direct and reverse waves, moved by a double travel time, t measuring points to the short circuit location, phase and interfacial voltages are measured, the moment of equal to zero effective values of one of the phase or interfacial voltages is recorded, and the total time shift interval is measured, the largest of which is judged on the distance to the point of short circuit.

The drawing shows a structural electrical circuit device

D71Y1 implementation of the proposed method. It contains voltage transformers 1, current transformers 2, BSCH measurements of modal components of voltage 3.4 and 5, units of measurements of modal component currents of 6.7 and 8, blocks of formation of direct modal waves 9, 10 and 11, blocks of formation reverse modal waves 12, 13 and 14, integration blocks 15-20, memory block and determining the location of damage 21,

The measurement process is as follows. The instantaneous values of the phase voltages at any point of the transmission line containing the Longitudinal and Transverse Compensation and Tuning device are expressed in terms of three forward and three reverse modal waves measured at the beginning of the transmission line. The point at the beginning of the integration is taken to be located in the middle of the time interval during which the wave is memorized. The signs in front of the waves and the travel time of the wave on the line from one segment to another, allocated by the compensation or adjustment device, are determined by the specific location of the device in the power line, and also depend on the presence of transposition points.

When a short circuit occurs, blocks 3, 4 and 5 measure the component voltages of the first, second, and third modes, respectively, and blocks 6, 7, 8 measure the three modal components of the current flow. Blocks 9, 10, 11 form direct modal waves Vfli ,, Vj) rj) and blocks 12,13, g14 are reverse Chl / ,, jWn sVn,. All waves then enter the integration blocks 15-20 Then, the values of the obtained waves and the integrals from them enter into block 21, where the inverse waves and proportional values. their integrals are shifted straight forward, multiplied by the corresponding coefficients and added. At each specified shift interval, the effective value of each phase and phase-to-phase voltage is calculated. If one of these values is zero, the shift stops. The total shift of the waves relative to the straight line is equal in double the travel time of the corresponding modal wave from the measuring point to the point of damage. The attenuation is taken into account by introducing an exponential coefficient.

In the first one or two half-periods, after the occurrence of the closure, the waves have a large frequency spectrum. The surface effect of the earth strongly distorts the high-frequency components of the waves, which affects the accuracy of determining the location of the damage. When calculating the distance to the place of damage, Poetzm should take a time delay for two half periods relative to the beginning of the measurement.

Claims (2)

1. Author's certificate of the USSR 458784, 0.01Х 31/08, 1974. 2. For registration No. 2468233/21, cl. G, 01R 31/08, 03/29/77, the software of which made the decision to issue a copyright certificate prototype). poq.