SU980023A1 - Device for measuring distance to power line damage location - Google Patents

Description

comparator unit, the first and second keys, the display unit, the signal character changing unit, a switch, a phase-sensitive rectifier and voltage smoothing unit, a third key, the first and second And elements, a pulse counter, a decoder, and the outputs of intermediate current transformers connected to the switch inputs, one of the outputs of which is connected to the input of the rectifier and current smoothing unit and one of the inputs of the phase-sensitive rectifier unit and voltage smoothing, the other output of the switch with another input of the phase-sensitive straightening and smoothing unit, the output of which is connected to one of the inputs of the first and second keys through the serially connected signal-changing block and the integrator to one of the inputs of the comparator, the output of which is connected to the control inputs of the first and second keys the output of which is connected in series through a pulse counter and a decoder connected to the input of the display unit, the second input of the first element I is connected via a third key to one of the integrator's inputs, secondly The input of the second element is And, the output of which is connected to the input of the initial reset of the pulse counter, and the first input of the second element And is connected to the output of the threshold element and to the input of the first time element, the output of which is connected to the second input of the first element And and to the input of the second element time, the output of which is connected to the third input of the first element I, the output of the rectification and current smoothing unit is connected to the input of the threshold element and to the input of the first key, the output of which is connected to one of the inputs of the comparator, and d of the second switch is connected to one input of a sign change signal block.

FIG. 1 shows a block diagram of a device for a three-phase controlled network; in fig. 2 - one of the variants of the concept of individual units of the device; in fig. 3 - timing diagrams for the operation of the device.

The device contains intermediate current transformers 1-3 and 4 - 6 voltages connected to phases A, B. C, switch 7, which ensures the selection of damaged current and voltage phases, rectifying unit 8 and current smoothing,

phase-sensitive unit 9 for straightening and smoothing the voltage, spring element 10, first and second time elements 11 and 12, respectively, first, second, and third keys 13-15, unit 16 for changing the sign of the signal, integrator 17, unit 18 for comparing, respectively the first and second elements And 19 and 20, the counter 21 impulses, the decoder 22, the block 23 of the display.

FIG. Figure 2 shows the basic electrical diagram of the Yu-21 blocks.

The operation of the device consists in determining the reactive component of the circuit's impedance proportional to the distance to the point of damage.

The device works as follows.

When a short circuit occurs, switch 7 provides for the selection of damaged phases, and a negative signal appears on the outputs of the rectifying and smoothing unit 8 and the phase-sensitive rectifying unit and of smoothing the voltage, respectively, and a positive signal sin f.

Claims (2)

When a short circuit occurs, the switching unit 7 provides the choice of rectifying the damaged phases, and at the outputs of blocks 8 and 9, respectively, a rectified and smoothed positive voltage K USlMtf and a negative voltage appear. In this case, under the action of voltage - | 3, the threshold element U is triggered and a negative signal appears at its output. Since at the first moment of time the first element 11 of time does not change its state during the period of its exposure -. (Fig. 3) at the inputs 1 and 2 of the second element 2O And there are negative resolution signals. In this case, the second element 20 And is triggered and provides Reset of the counter 21 to the initial state. For a time approximately equal to O, O4 s, the capacities of the smoothing filters in blocks 8 and 9 are charged, and the voltages K U bin f reach values close to steady state. Under the action of a negative signal taken from the output of the time element 11, the third key 15 is open, the capacity of the integrator 17 is discharged, and there is no signal at its output. At the same time at the output of the comparative block 18 there is a positive signal, so the first and second keys 13 and 14 are closed. After the expiration of the time delay i о at the output 598 of the first element 11 of time, a positive signal appears, arriving at the input 2 of the second element 20 I and ensuring its blocking. Since at the first moment of time the second element 12 of time does not change its state, during the time of its pin 3), approximately equal to 0.04 s, the second and third inputs of the first element 19 And there are positive resolution signals and it is possible to count the number voltage pulses | Jg, arriving at the first input of the first element 19 and from the output of the comparative block 18. A positive signal from the output of the first element 11 time arrives tatok to the input of the third key 15 and closes it. Since at the first moment of time the first and second keys 13 and 14 are closed, the signal K and passes to the input of the element comparing unit 18 unchanged, and the signal KnUeiuM is converted in blocks 16 and 17 in such a way that the integrated value of this signal in the form of voltage and (Fig. 3), increasing linearly. When this voltage U L / is reached (time 4. in Fig. 3), the comparating unit 18 switches and a negative signal appears at its output (Jr. At the same time, the first and second keys 13 and 14 open, the voltage signal V - arriving at the input of comparation block 18 becomes equal to zero, and stresses and g begins to decrease linearly due to a change in the sign of the signal P of the help of block 16 of the change of sign of the signal. At the time) the voltage decreases to zero and There is a sign that leads to the appearance of a positive example. voltage VX at the output of block 18 komparatsii. At the same time, the first and second keys 13 and 14 are closed and the work cycle is repeated. The duration of the pulses and g and 1) 5 p is directly proportional to the voltage k J and is inversely proportional to the voltage K j CD) Ip. In this case, the number of AND pulses during a given reference time is directly impacted by the reactive component of the complex resistance, i.e., jiii5, Kie «x and, therefore, proportional to the risk to the site of damage. After the time of the second element of time 12 is exhausted for 23A (at time-1,), a negative voltage appears at its output, the first element 19 of AND blocks and stops counting pulses. When choosing a sufficiently large capacitance of the counter, which provides for the counting of pulses of sufficiently high frequency, increased accuracy is ensured due to a decrease in dynamic error. due to unsteady voltages and Q, Ucin / - When choosing the counting time -. {; p multiple of the industrial frequency period, the pointer accuracy also increases due to the reduction in error due to poor quality smoothing of the measured voltages, since the number of pulses AND is proportional to the mean value of the quantities and is practically independent of the level of the variable component. The latter also leads to a decrease in the measurement error when the input current and voltage are distorted. The invention The device for measuring the distance to the fault on the power lines, containing intermediate current and voltage transformers, respectively, the number of phases of the controlled face, the unit for straightening and smoothing the current, the spring element, the first time element and the second time element , an integrator, a comparation unit, the first and second keys, an indication unit, a unit for changing the sign of the signal, characterized in that, in order to improve the accuracy of the measurement, a switch, a phase-sensitive straightening and smoothing unit are introduced into it voltage, the third key, the first and second elements And, the pulse counter, the decoder, and the outputs of intermediate current and voltage transformers are connected to the inputs of the switch, one of whose outputs is connected to the input of the power supply unit and current smoothing and one of inputs of the phase-sensitive rectifier unit and voltage smoothing, the other output of the switch is connected to another input of the phase-sensitive rectifier unit and voltage smoothing, the output of which is connected through the series-connected unit The signal akta and the integrator is connected to one of the inputs of the comparator unit, the output of which is connected to the control inputs of the first second and second keys and with the first input of the first element I, the output of which is connected through a serially connected pulse counter and decoder to the input of the inditsi block; the second input of the first element I is connected via a third key to one of the integrator inputs to the second input of the second element I | stroke which is connected to the input of the initial reset of the pulse counter, and the first input of the second element And is connected to the output of the threshold element and to the input of the first time element, the output of which is connected to the second input of the first element And and to the input of the second time element, the output of which is connected to the third input of the first element I, the output of the rectifier and current smoothing unit connected to the input of the threshold element and to the input of the first key, the output of which is connected to one of the inputs of the comparation block, and the output of the second key is connected to one of the inputs of the block that changes the sign of the signal. Sources of information taken into account in the examination 1, Fixed impulse device FIP-2. Technical description and operating instructions. Riga, 198O. 2. Gelfand Ya.S. et al. Resistance relay using a pulse-width dividing device. Electricity, 1979, NO 9, p. 15 20 (prototype). fiCf-I K and sin V Fig.Z