SU1108552A1 - Device for determining earth fault location in excitation winding of synchronous machine - Google Patents

Abstract

A DEVICE FOR DETERMINING THE LOCATION OF THE CIRCUIT ON THE HOUSING OF THE SYNCHRONOUS MACHINE EXCITATION, containing the first voltage sensor, the memory unit, the division unit, the comparator, the driver of the pulses, two adders, the outputs of the adders are connected to the corresponding inputs of the division unit, the output of which is connected to one of the computer inputs , and the output body, characterized by the fact that, in order to expand the functionality, the device is supplemented by a second voltage sensor, and the output body is made in the form of a display unit and the element C the first voltage sensor is connected between one of the terminals of the excitation winding of a synchronous machine and its case, the second voltage sensor is connected between the second terminal of the excitation winding of a synchronous machine and its case, the output of the first sensor. Voltage is connected to the first input of adders, the second a voltage sensor is connected to the second inputs of said adders, the input of the pulse driver is connected to the output of the first adder, and its outputs are connected to the control inputs of the division unit and the memory unit, and The information input of the memory unit is connected to the output of the division unit, the output of the memory unit is connected to the input of the display unit and the second input of the comparator, whose output is connected to the input of the alarm element.

Description

The invention relates to relay: protection, namely to the protection of the excitation winding of synchronous machines against. short circuits to the housing. It is known a ground fault protection device at one point of the excitation circuit of a synchronous machine, which contains a source of operating current, a current sensor, current-limiting resistances and a comparator, the source of operational current being connected through current-limiting resistances between the two excitation windings and the ground. If the measured current value exceeds the reference value, the device generates a signal to turn off the synchronous masking 13. A disadvantage of the known protection device is the impossibility of determining the location of the circuit, which is especially important to know when the circuit disappears on the stopped synchronous machine. The closest to the present invention is a device for protecting the excitation windings against zamps containing a first resistance, a DC source and a current converter connected in series between one of the excitation windings and ground, a sensor connected in parallel to the first resistance, the second resistance connected between the second glue excitation winding and the current transducer through a switch, pulse former, connected to the output of the current transducer or sensors ik voltage, the output of the pulse driver is connected to the control inputs of the switches and memory blocks, information (the ion input of the first memory block is connected to the output of the current converter, and its output to the input of the first adder, the information input of the second memory block is connected to the output the voltage sensor and its output - with the input of the second sum of the matrix; The outputs of both adders are connected to the corresponding inputs of the division unit whose output is connected to the input of the comparator 2. The drawback of the device is its limited function. e features that are due to the fact that the device does not permit to determine the place of occurrence of the first circuit to drive the armature winding machine pus, and to record the occurrence of the second circuit to the housing. The purpose of the invention is to expand the functionality of the device. The goal is achieved by the fact that the device for determining the location of the closure to the case of the excitation winding of a synchronous machine, contains the first voltage sensor, a pulse shaper, two adders, a dividing unit, a memory unit, a comparator, the outputs of the adders are connected to the corresponding inputs of the dividing unit, the output of which connected to one of the inputs of the comparator, and the output organ, supplemented by a second voltage sensor, and the output organ is implemented as a display unit and an alarm element, with the first voltage sensor Connected between one of the terminals of the excitation winding of the synchronous machine and its case, the second voltage sensor is connected between the second terminal of the excitation winding of the synchronous machine and its case, the output of the first voltage sensor is connected to the first input of the adders, the output of the second voltage sensor is connected to the second inputs chick adders, the input of the pulse former. ow is connected to the output of the first adder, and its outputs are connected to the control inputs of the dividing unit and the memory unit, the information input of the memory unit is connected to the output of the dividing unit, the output of the memory unit is connected to the input of the indicating unit, and the second input of the comparator, the output which is connected to the input element of the alarm. Fig. 1 shows a functional diagram of the proposed device, Fig. 2 shows a replacement scheme. The device contains voltage sensors 1 and 2, adders 3 and 4, dividing unit 5, pulse shaper 6, memory unit 7, comparator 8, alarm element 9, indication unit 10, voltage sensors 1 and 2 being connected between positive and negative the terminals of the excitation winding 11 of the synchronous machine and its casing 12. The output of the first voltage sensor 1 is connected to the first inputs of adders 3 and 4, the output of the second voltage sensor 2 is connected to the second inputs of adders 3 and 4, the outputs of the adders 3 and 4 are connected to the corresponding inputs block 5 case In addition, the output of the first adder 3 is also connected to the input of the pulse former 6, the outputs of which are connected to the control inputs of the division unit 5 and the memory unit 7, the information input of the memory unit 7. connected to the output of division block 5. The output of memory block 7 is connected to the input of display unit 10 and the second input of comparator -8, the second input of comparator 8 is connected to the output of division block 5, and its output is connected to the input of alarm element 9.

The first adder 3 is designed to generate a signal equal in magnitude to the difference of the signals from the output of sensors 1 and 2. The second adder 4 is designed to generate an x signal of equal magnitude to the sum of the signals from the outputs of sensors 1 and 2, the pulse shaper 6 is designed to control the operation of the unit 5 divisions and memory block 7, with a pulse permitting the recording of information in memory block 7 to appear with a delay with respect to the signal permitting the operation of division block 5. This delay is required dp detuning from the time of operation of the unit 5 division. The display unit 10 is designed to indicate the place of occurrence of the first circuit of the excitation winding 11 of the synchronous machine to its casing 12. The signaling element 9 serves to signal the occurrence of a second circuit of the excitation winding 11 to the casing.

In addition, FIG. 1 shows the point of the first closure of the excitation winding 11 to the housing 12, K. is the point of the second closure.

The device works as follows.

From the replacement circuit of the excitation circuit by the constant Toky (Fig. 2), it follows that when an excitation winding 11 closes, for example, at point K, voltages appear at the outputs of sensors 1 and 2, the expressions for defining which look like

) (v.) () -

where and.,, 1/2 of the voltage at the outputs of the first 1 and second 2 voltage sensors; (J is the value of the voltage applied to the excitation winding 3, R R is the active resistance

winding 11 excitation to the point of closure; - resistance of the measuring part of the sensor 1. (2) voltage; I have a constant coefficient

transform.

The voltages U and U are fed to the corresponding inputs of adders 3 and 4. At the output of the first adder 3, a signal appears, the expression for which is

 X.

(R, R, | tZ-HA at the output of adder 4, a signal appears proportional to the magnitude of the excitation voltage of the synchronous machine,

I (From the outputs of the adders 3 and 4, the received signals then go to the corresponding inputs of the 5 de / geni block. In addition, the signal from the output of the first adder 3 is also supplied to the input of the pulse generator 6, which, when the input signal deviates from zero, allows the block 5 to work dividing and, with some delay, generates a signal permitting the recording of information from the output of dividing unit 5 into memory unit 7.

At the same time, at the output of dividing unit 5, a signal appears that is proportional to the waveform from dividing

About 1.-.

(five

Accepted / R HR, R2 (l-h), - fR2 where R is the active resistance value of excitation winding 11,. - the distance to the place of the first closure to the case from one of the terminals of the excitation winding 11 in relative units, ()

(6)

t, 1- - f-2ri (l-n) then expression (6) since R takes the form (T) i From expression (7) it is clear that the dependence of m on n is single-valued and linear; When changing n from O to 1, the value of t varies linearly from -1 to 1. The closure of the excitation winding 11 to the body at one of its points, located between the middle of the winding 11 (in length) and the connection point e to the positive pole of the exciter (represented in Fig. 2 by the source of emf) correspond to negative values of the closure of the excitation winding 11 to the core at any other point located between the middle of the winding and its connection point to the negative pole of the exciter - positive values. Thus, it is not difficult to know the value of a wire. It is easy to determine the place of the closure of the excitation winding 11 of the synchronous machine on the body. The signal from the output of the dividing unit enters the information input of the memory unit 7. After the signal from the output of the pulse generator 6 comes to the control input of this block, n is stored in the memory, after which the recording of the new value of the output from the block dividing block 5 already From the output of memory block 7 is impossible, the input m is displayed to 10 indications signaling the location of the first circuit y and excitation winding 11 to the housing: and to the second input of the comparator 8, and at the same time the first input of the comparator 8 receives a signal from the output of the dividing unit 5, and since the values of these signals are equal, its output The logical zero level is not saved. At the occurrence of a second closure, the signal Yn appears at the output of dividing unit 5; its value is determined by the expression m, 2. (2n-1 + 1) / () where nij is the signal at the output of dividing unit 7; k is the distance from the point of the first closure of the winding on the case to the point of the second closure in relative units (Fig. 1). Expression (8) is obtained by substituting the values, i (and making the necessary abbreviations into expression (5). Comparison of expressions (7) and (8) shows that tn is always greater than m. Consequently, when a second short circuit occurs at the output of comparator 8 along is a signal with the level of a logical unit, which is fed to the input of the element 9 of the signaling, the ignition of which indicates the occurrence of the second circuit of the excitation winding 11 of the synchronous machine to its body 12. Thus, the use of the invention will expand tional yozmozhnosty it, namely to determine the place of occurrence of the first and second circuit on the body.

FIG. 2

Claims (1)

DEVICE FOR DETERMINING THE LOCATION OF CIRCUIT BETWEEN THE CIRCUIT OF EXCITATION OF THE SYNCHRONOUS MACHINE, Containing the first voltage sensor, memory unit, division unit, comparator, pulse shaper, two adders, the outputs of the adders are connected to the corresponding inputs of the division unit, the output of which is connected to one of the inputs of the comparator, output organ, characterized in that, in order to expand the functionality, the device is supplemented by a second voltage sensor, and the output organ is made in the form of an indication unit and an alarm element the first voltage sensor is connected between one of the field winding terminals of the synchronous machine and its body, the second voltage sensor is connected between the second terminal of the field winding of the synchronous machine and its body, the output of the first sensor. The voltage is connected to the first input of the adders, the output of the second voltage sensor connected to the second inputs of the said adders, the input of the pulse former is connected to the output of the first adder, and its outputs are connected to the control inputs of the division unit and the memory unit, information nny input memory block connected to the output of division unit, a memory unit output is connected to the input of the indication unit p and the second input of the comparator-output of Ko 'U torogo connected to the input member and · * signaling. mmd ABOUT 00 SP SP №> 1 1108552 2