SU1499282A1 - Method of determining the distance to the place of single-phase short-circuit to the ground of electric power line - Google Patents

Abstract

The invention can be used to determine the distance to a high voltage line. The method is implemented in the device. The purpose of the invention is to improve the measurement accuracy by converting a single-phase earth fault to a short circuit and measuring on a line model — this is achieved by translating the single-phase earth circuit to a single-phase short circuit for the measurement time, select the damaged phase and measure the active instantaneous component the value of the voltage of the damaged phase and the active component of the instantaneous value of the voltage drop on the model specific portion of the line from the emergency mode current at the time when the instantaneous value t The zero sequence value is zero, the first measured value is divided by the second, and the distance to the fault is determined by the result of the division. 1 il.

Description

The invention relates to an electrical measuring technique, namely, to a technique for determining the distance to a high-voltage damage site.

SRI.

The purpose of the inventions is to improve the measurement accuracy by translating a single-phase short circuit to earth into a short circuit and measurements on a line model.

The drawing shows a diagram of the device that implements the method.

The device contains the first threshold element 1, included in the neutral

transformers 2 current. The first input of the first IZ logic element is connected to the output of the first threshold element 1, and the output of the second threshold element 4, the input of which is connected to the output of the first voltage transformer 5, is connected to the second input. The output of the first logic element And 3 is connected to the input-relay 6 time, the output of which is connected to the contactor 7. The output element of the time delay

8 connected to the first inputs of the first

9 and the second 10 keys. The second inputs of the first keys 9 are connected to the model 11 specific line segment, which

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also connected to the outputs of the respective transformers 12 current. The outputs of the keys 9 are combined and connected to the first input of the first element 13 of the phase shift, and its second input is connected to the common point of model 11. The output of the first element 13 of the phase shift through the first null organ 14 is connected to the first input of the first synchronous detector 15. The second the input of the first synchronous detector 15 is connected to the first input of the second synchronous detector 16, the first input of the third synchronous detector 17 and to the output of the second null organ 18. The output of the first synchronous detector 15 through the first integrating circuit 19, the converter 20 It is not connected to the first input of the second logic element 21, the output of which is connected to the display unit 23 via the decoder 22. The second inputs of the second switches 10 are connected to the second voltage transformers 24. The outputs of the second keys JO are interconnected with the first input of the second integrating circuit 25. The second input of the second integrating circuit 25 is connected to the neutral of the second voltage transformer 24, the second input of the third synchronous detector 17 and the first input of the second phase shift element. The second input of the second phase shift element 26 is connected to the third input of the third synchronous detector 17 and to the outputs of the second switches 10. The output of the second phase shift element 26 is connected via the third null organ 27 to the second input of the second synchronous detector 16, the output of which is through the third integrating circuit, 28, the second voltage converter 29 is connected to the first input. the first digital-to-analog converter 30. The second input of the first analog converter 30 is through the third voltage converter 31, the fourth integration circuit 32 is connected to the output of the third synchronous detector 17. The output of the first diffro-analog converter 30 is connected to the first input of the second digital-analog converter 33, the output of which is connected to the second input second logical element And 21. The second. the input of the analog to analog converter 33 via the second voltage converter 34 is connected to the output of the second integrating circuit 25.

The method is carried out as follows.

When a single-phase ground fault occurs, for example, phase A, the first threshold element 1 is triggered, fixing the appearance of the zero sequence current and the second threshold element 4 is triggered, fixing the appearance of zero sequence voltage, the element 3 triggered, which activates the time relay 6, if the damage was not eliminated during the operation of the time relay 6, then it switches on the contactor 7, which transfers the line from the single-phase short circuit mode to the single-phase short circuit mode to the measurement time. In this case, keys 9 and 10 are activated from the protection of phase D via the time delay element. Similarly, if the phases B or C are damaged, respectively, the corresponding keys are activated through the locking elements of the switchgear. Via key 9, the voltage drop across the model 11 of the specific portion of the line from the fault current is supplied to the phase shift element 13 and through the first zero-body 14 to the first synchronous detector 15, which is controlled by the zero-sequence current from the second zero-body 18. Null The organ 18 fixes the moment of the current passing through the zero sequence through zero. At the output of the first synchronous detector 15, we get Di Eu 1d81p ((, - - Ц д), where is the resistance of the specific line segment model, Ifl is the phase current of phase A); tfi is the initial phase angle of the phase current, (fg is the initial phase angle of the zero-sequence current, this voltage is fed through the first integrating circuit 19 to the first voltage converter 20, made for example in the form of a Rower multivibrator, and then to the second logic element I 21. The key φ applies the voltage of the damaged phase to the phase shift element 26, to the synchronous detector 17 and to the integrating circuit 25. From the second phase shift element 26, the voltage of the third null organ 27 is fed to the second synchronous detector 16, which controls with a zero-sequence current from a null-organ 18. At the output of the second synchronous detector 16, we also get U s1n (0) c - Cf), where Urn is the phase voltage of the network, If c is the initial phase angle of voltage U 11, this voltage is fed through the third integrated circuit 28 to the second voltage converter 29 and from it to the digital-to-analog converter 30. At the output of the third synchronous detector 17, which is controlled by the zero-sequence current from the second zero-organ J8, we get u U (p. cos (t | u - tfj), this voltage through the fourth integrating circuit 32 is fed to the third voltage converter 31, the output of which is connected to the first R. IRFRO analogue converter 30, at its output we get U

 uJ.sinCtfu-tfo cosCc o-t | e) - This voltage is applied to the second digital-to-analog converter 33,

More on display unit 23. Measurement accuracy is achieved by converting a single-phase earth fault to a single-phase short circuit.

Claims (1)

Invention Formula The method of determining the distance to the single-phase ground fault of the transmission line, based on measuring the instantaneous value of the voltage of the damaged phase and comparing it with the voltage derived from the current of the add-on mode on a specific line segment model, characterized in that, in order to improve the measurement accuracy , single-phase short circuit to earth for the measurement time is converted to single-phase short-circuit the second input of which is fed directly to the 20th, selects the damaged phase and failure of the phase through the second integrated circuit 25 and the second voltage converter 34. At the output of the second digital-to-Log converter 33, we obtain Vf (tpu -) cos (voltage is applied to the second logic element AND 21, at the output of which we obtain a value proportional to the distance to the fault location 1 measure the active component to the instantaneous value of the voltage of the damaged phase and the activenumber make up the instantaneous value of the fall of the voltage on the engine and the specific portion of the line from the emergency mode current at the time when the instantaneous value of the zero sequence current is zero, the first measured magnitude - Uj (30 well for the second, and the distance to the place & U damage is determined by the result it is fed to the decoder 22 and dividing. measure the active component to the instantaneous value of the voltage of the damaged phase and the activenumber make up the instantaneous value of the fall of the voltage on the engine and the specific portion of the line from the emergency mode current at the time when the instantaneous value of the zero sequence current is zero, the first the measured value is 30 second and the distance to the place Tg From protection of TT 11 phase X jsk Opzashm- tyfl (