RU2282925C1 - Method and device for suppressing magnetic field of excitation winding of synchronous machine (variants) - Google Patents

Abstract

FIELD: electric engineering, namely engineering of excitation systems for synchronous machines, namely, devices for suppressing magnetic field of excitation winding of synchronous machines.

SUBSTANCE: method for suppressing magnetic field of synchronous machine is performed by measuring voltage on excitation winding, comparing it to setting, and each time when this voltage decreases to level of setting, resistance of resistor in passage contour of excitation current is increased by one step up to value equal to relation of voltage, maximally allowed in accordance to operation conditions of excitation winding isolation, to current value, at which voltage reached the setting. In accordance to first variant of device for realization of current method, resistor is divided on two similar portions, between which commutator is inserted, containing two oppositely included parallel thyristors, in parallel to which contactor is connected. In parallel to part of this circuit, consisting of serially connected commutator and resistor, the latter being connected to clamp of excitation winding, connected to positive pole of excitation device, a branch is connected, containing serially connected: resistor, connected to clamp of excitation winding, connected to positive pole of excitation device, and thyristor, cathode of which is connected to aforementioned resistor. At the same time in parallel to circuit, containing serially connected commutator and resistor, connected to clamp of excitation winding, which is in turn connected to negative pole of excitation device, a branch is connected, containing serially connected: thyristor, anode of which is connected to clamp of excitation winding, connected to negative pole of excitation device, and another resistor, in parallel to which a capacitor is installed. Clamp of excitation voltage indicator is connected to first input of logic block. Circuits for controlling thyristors, anodes of which are connected to resistor, connected to clamp of excitation winding, connected to negative pole of excitation device, are combined and connected to first output of logic block. At the same time, circuit for controlling thyristor of field suppression device, connected by cathode to resistor, connected to clamp of excitation winding, connected to negative pole of excitation device, is connected to second output of logic block. Block-contacts of automatic switch are connected to another input of logic block. Third output of logic block is connected to circuit for controlling thyristor of field suppression device, connected by anode to output of excitation winding, connected in turn to negative pole of excitation device. In accordance to second variant of device for realization of current method, for decreasing machine field suppression time, resistor is divided on "n" similar sections, while commutator is installed between first and second parts of resistor, counting from clamp of excitation winding, connected to positive pole of excitation device. Branch, which contains serially connected thyristor and resistor, in parallel to which capacitor is connected, by anode of thyristor is connected to connection point of second and third parts of resistor, counting from clamp of excitation winding, connected to positive pole of excitation device. By clamp of resistor the aforementioned branch is connected to clamp of first part of resistor, connected simultaneously to commutator and to output of excitation winding, connected to positive pole of excitation device. Similar following branches are connected in parallel to each section of circuit, containing resistor and thyristor of previous similar branch, which by anode is connected to connection point of current and previous resistor. By contact of resistor such a branch is connected to cathode of thyristor of previous similar branch.

EFFECT: decreased suppression time of synchronous machine field while maintaining simplicity of device, meant for realization of proposed method for suppressing magnetic field of excitation winding of synchronous electric machine.

3 cl, 8 dwg

Description

The invention relates to excitation systems of synchronous machines, namely, devices for damping the magnetic field of the excitation winding of synchronous machines.

Known methods in which to suppress the magnetic field of the field winding (RH) are used to dissipate the RH energy at the active constant resistance, to dissipate the RH energy on the arcing grid of the switch in the excitation circuit, transfer the converter of the excitation system of a synchronous machine to invert mode [1, p. 13, 33, 37].

The disadvantage of the method of damping the field by dissipating the energy of the active medium at the active constant resistance is the long damping time of the field, which leads to an increase in the amount of destruction during a short circuit (short circuit) in the circuit the machine was working on, especially when a short circuit is in the differential protection zone of the machine.

The disadvantages of the method of damping the field by dissipating the energy of the OM on the arcing lattice are the design complexity and the high cost of the device that implements this method of damping the field.

The disadvantage of the method of damping the field by converting the converter to inverting mode is its inefficiency at low voltage on the converter, which occurs in systems of thyristor self-excitation of synchronous generators at close to the short-circuit generator.

The closest technical means to the invention is a method of damping the magnetic field of the excitation winding of a synchronous machine, which consists in dissipating the energy of the active current at the active constant resistance, which allows to implement the simplest device [1, p.13].

The technical problem is to obtain a short damping time field synchronous machine while maintaining the simplicity of the device that implements the method.

The specified technical problem is solved by the fact that in the known method of quenching the magnetic field of the field winding of a synchronous machine, which consists in dissipating the energy of the magnetic field of the field winding on an active linear resistance, according to the invention, the voltage at the terminals of the field winding is additionally measured and compared with the setpoint, while decreasing the measured voltage up to the set voltage, the active resistance is increased by one step to a value equal to the ratio of the voltage maximum permissible oviyam excitation winding insulation work, to a current value at which the voltage reaches the setpoint.

Measurement of the voltage at the terminals of the field winding and a stepwise increase in the active discharge resistance as the field current decreases, the average value of the voltage at the terminals of the extractors during the field blanking is high - close to that acceptable under the operating conditions of the isolation of the extractors. This allows you to reduce the field blanking time to normalized.

To implement this method, a magnetic field damping device for a field winding of a synchronous machine is provided, comprising a circuit breaker connected in series with the field winding, as well as a voltage sensor connected in parallel with the field winding and a circuit consisting of series-connected active resistance and a switch containing two parallel opposite connected thyristors and a contactor connected in parallel with it, in which according to the invention said active resistance This is divided into two identical parts, and the switch is connected between them, and parallel to the part of this circuit, consisting of a series-connected switch and active resistance connected to the output of the field winding connected to the positive pole of the exciter, a branch is connected containing series-connected active resistance, connected to the output of the field winding connected to the positive pole of the pathogen, and a thyristor, the cathode of which is connected to this resistance; parallel to the circuit containing the switch connected in series and the active resistance connected to the output of the field winding connected to the negative pole of the exciter, a branch is connected containing the series-connected thyristor, the anode of which is connected to the output of the field winding connected to the negative pole of the exciter, and other active resistance, parallel to which a capacitor is connected; the output of the excitation voltage sensor is connected to the inputs of two comparators of maximum action and a comparator of minimum action; thyristor control circuits, the anodes of which are connected to the active resistance connected to the output of the field winding, connected to the negative pole of the exciter, are combined and connected to the output of the minimum comparator; the thyristor control circuit of the field suppression device connected by the cathode to the active resistance connected to the excitation winding terminal connected to the negative pole of the exciter is connected to the output of the first maximum action comparator; block contacts of the circuit breaker are connected to the input of the first logic element of the type "NOT" and the input reset four binary digit counter; the output of the first logic element of the type “NOT”, the output of the second logic element of the type “NOT” and the output of the second maximum comparator are connected to different inputs of the logic element of the type “AND”, the output of which is connected to the non-inverting input of the binary four-digit counter; the zero-bit output of the binary four-digit counter is connected to the thyristor control circuit of the field suppression device connected by the anode to the output of the field winding connected to the negative pole of the pathogen; the input of the second logic element of the type "NOT" is connected to the output of the first bit of the binary four-digit counter.

The invention is illustrated by drawings, where in Fig.1 shows a schematic electrical diagram of the power part of the device, Fig.2 is a diagram of its logic unit, and Fig.3 is a timing diagram of the voltage of the field winding and the state of the logical signals of the field suppression device. Figure 4 shows the timing diagrams of the current and voltage of the field winding obtained by simulating the operation of the device in the Matlab environment for the case of damage in the differential protection zone of the machine. Figure 5 shows a circuit diagram of the power part of the device (option 2), figure 6 is a diagram of its logic block with the number of stages of the field blanking device equal to four, and figure 7 is a timing diagram of the voltage on the excitation winding and the state of the logic field blanking device signals. On Fig shows time diagrams of the current and voltage of the field winding obtained by simulating the operation of the device in a Matlab environment for the case of damage in the differential protection zone of the machine.

The magnetic field damping device of the field winding 1 connected to the exciter 2 of the excitation system (FIG. 1) comprises a circuit breaker 3 connected in series with the field winding, a power part 4 connected in parallel with the field winding. The device contains an excitation voltage sensor 5, to the output of which through the inputs of the logic unit 6 (Figure 2) are connected a comparator 7 of a minimum action and comparators of a maximum action of 8 and 9; the output of the comparator 7 is connected simultaneously to the control circuits of the thyristors 10 and 11. The output of the comparator 8 is connected to the control circuit of the thyristor 12, and the output of the comparator 9, the output of the logic element 13 of the type “NOT” and the output of the logic element 14 of the type “NOT” are connected to different inputs of the logical element 15 of the "I" type, the output of which is connected to the non-inverting input of the binary four-digit counter 16. The block contacts of the circuit breaker 3 are connected simultaneously with the input of the logic element 13 of the type "NOT" and with the reset input of the counter 16; the output of the zero discharge of the counter 16 is connected to the control circuit of the thyristor 17, the output of the first discharge of the counter 16 is connected to the input of the logic element 14 of the type "NOT". The power part 4 (Fig. 1) contains two series-connected active resistances 18 and 19, between which two counter-current parallel thyristors 10 and 12 are connected, a contactor 20 is connected parallel to these thyristors. Parallel to the part of the circuit containing the thyristor 10 connected in series to the cathode of which an active resistance 19 is connected, connected to the output of the field winding connected to the positive pole of the pathogen 2, a circuit is connected containing series-connected thyristor 11, to the cathode of which is connected active resistance 21 connected to the output of the excitation winding 1 connected to the positive pole of the pathogen 2. Parallel to the part of the circuit containing the thyristor 10 connected in series, an active resistance 18 connected to the output of the excitation winding 1 connected to the negative pole of the exciter 2 is connected to the anode a circuit is connected containing the thyristor 17 connected in series, to the cathode of which an active resistance 22 is connected, in parallel to which a capacitor 23 is connected.

The method of damping the magnetic field of the field winding is as follows.

In normal operation of the excitation system, there is no signal from the relay protection circuits of the RE (Figure 1). This ensures that the outputs of the logic unit 6 lack of control signals of the power part 4. The circuit breaker 3 is in the on state. The excitation current flows through the pathogen 2, the field winding 1 and the contacts of the switch 3.

When a signal appears to turn on the field damping device from the relay protection circuits of the RE of the machine, switch 3 breaks the excitation circuit. The voltage at the field winding 1 changes sign (Figs. 3, 4a) and when it reaches the set value, the logic unit 6 gives a signal to put into operation the power part 4, which connects the active resistance parallel to the field winding. The resistance of this circuit is much less than the resistance of the arc of the switch 3, therefore, the current of the field winding 1 begins to flow along this circuit and at the same time decreases (Fig. 4b) with the time constant of the circuit formed by the field coil 1 and the resistance of the power part 4. At the same time, the voltage across the winding excitation 1 (Fig.3, 4A). When the voltage on the field winding reaches the setpoint, the logic unit 6 generates a control signal for the power part 4, which leads to a change in the circuit and an increase in the resistance of the power part 4 and, as a result, an increase in the voltage on the field winding 1 to an acceptable level and faster energy output from her. Each time, when the voltage on the field winding 1 is reduced to the setpoint level, the logic unit 6 is activated again, increasing the resistance of the power part 4. The damping of the magnetic field is completed at the last stage of the active resistance of the power part 4.

A device for damping the magnetic field of the field coil that implements the proposed method works as follows.

When the synchronous machine is operating, the voltage at the terminals of the field winding 1 is always higher than the setting of EZ-1 of the comparator 7 of the minimum action, below the setting of EZ-2 of the comparator 8 of the maximum action and above the setting of EZ-3 of the comparator 9 of the maximum action (Figure 2). Therefore, at the output of logic block 6 there are no control signals for thyristors 10, 11, and 12, and at the output of comparator 9, the signal has a logic level of “1” (Figure 3). The block contacts of switch 3 are closed. Therefore, the signal at the output of the logic element 13 has a logic level of "0", and at the input of the reset of the counter 16 - logical "1". The signal at the output of the logical element 15 of the type "I" has a logic level of "0", there are no signals at all outputs of the counter 16, and the signal at the output of the logic element 14 of the type "NOT" has a logic level of "1". All thyristors in the power part 4 are in the closed state, and the contacts of the contactor 20 are open.

The signal from the voltage sensor 5 is supplied to the comparators 7 and 9. When the signal for blanking the field arrives, the relay protection of the machine turns off the switch 3, which leads to a change in sign and a sharp increase in the voltage value 5 on the field winding 1 (Figure 3, time t1) , and also to the disappearance of the signal at the input of the reset counter 16 and the appearance of the signal at the output of the logic element 13 of the type "NOT". When this voltage becomes less than the setpoint EZ-1 of the comparator 7 of the minimum action, the signal at its output will have a logic level of "1", which will lead to the inclusion of thyristors 10 and 11 and the closure of the excitation current by resistance 18, 19, 21 (Figure 1) . The voltage on the field winding 1 is equal to the product of the field current on the resistance of the power part 4. As the magnetic field energy of the field winding 1 decreases due to its dissipation in the active resistances of the power part 4, the voltage at the terminals of the field winding 1 also decreases. When the value of this voltage becomes higher the setting level of EZ-3 of the comparator 9, a signal will appear at its output, which will lead to the appearance of a logical “1” signal at the output of the element of type “I” (Figure 3, time t2). The output signal of the element 15 is supplied to the counting non-inverting input of the counter 16, at the output of the zero discharge of which the logical level signal is set to “1” (Figure 3, Q0). This will turn on the thyristor 17 in the power part 4. In this case, at the first moment after turning on 17, the capacitor 23 is a short circuit, and the current in the thyristor 10 changes its direction, which leads to shutdown 10 and, as a result, an increase in the resistance of the power part 4. As a result of this, the voltage at the terminals of the field winding 1 is repeatedly increased to a value that is acceptable under the conditions of the insulation. As the energy of the magnetic field of the field winding 1 decreases, the voltage at its terminals decreases, which leads to the operation of the comparator 9 and the appearance of a second pulse at the input of the counter 16 (Figure 3, time t3). In this case, the signal at the output of the zero discharge of the counter 16 disappears, a signal appears at its output of the first discharge (Q1) and, as a result, the appearance of logic “1” at the input of the logic element 14 of the type “NOT”. This leads to the disappearance of the signal at the output of the logical element 15 of the type "And", which blocks the further operation of the device. The field blanking is completed at the second stage of the resistance of the power part 4. The device is returned to its initial state by applying a signal from the block contacts of the circuit breaker 3 of the excitation circuit at the time it is turned on (Figure 3, time t4). When this occurs, the counter 16 is reset, and a logical “0” from output 13 blocks the operation of element 15. The circuit is in the initial state.

The appearance of overvoltages of a different sign in any operating conditions of the machine will cause either the comparator 7 of the minimum action to turn on and turn on the thyristors 10 and 11, respectively, or the comparator 8 of the maximum action and turn on the thyristor 12. In this case, the field current 1 closes either at the resistance 18, 19 and 21, or the resistances 18 and 19 of the power part 4 (Figure 1). The voltage on the field winding 1, therefore, does not exceed the value permissible under the conditions of insulation strength. Therefore, the proposed device performs the function of protecting the field winding 1 from overvoltage.

Since the resistance of the power part 4, which is equal to the self-synchronization resistance, is connected parallel to the excitation winding 1, in the normal operating modes of the machine, the proposed device also implements the functions of self-synchronization circuits. As resistors included in the device, self-synchronization resistor elements are used, which are installed in typical excitation systems of synchronous generators. As a result, the dimensions of the proposed device and its cost are significantly reduced.

To implement this method, a magnetic field suppression device for a field winding of a synchronous machine (option 2) is proposed, comprising a circuit breaker connected in series with the field winding, as well as a voltage sensor and a circuit consisting of series-connected active resistance and a switch containing two parallel thyristor counterclockwise and a contactor connected in parallel in which, according to the invention, said active the resistance is made up of n equal parts, the switch is connected between the first and second parts of the active resistance, counting from the output of the field winding connected to the positive pole of the exciter, and parallel to the part of this circuit consisting of series-connected switch and active resistance connected to the output of the field winding, connected to the positive pole of the pathogen, connected to a branch containing a series-connected active resistance connected to the output of the field winding, Connections to the positive pole of the pathogen, and a thyristor, the cathode of which is connected to this resistance; a branch containing a thyristor and other active resistance connected in parallel, a capacitor connected in parallel, the thyristor anode is connected to the connection point of the second and third parts of the specified active resistance, counting from the excitation winding connected to the positive pole of the exciter, and the output of the other active resistance is connected to the output of the first parts of the active resistance connected simultaneously with the switch and with the output of the field winding connected to the positive floor Su pathogen; subsequent (other) similar branches are connected in parallel to each part of the circuit containing the active resistance and the thyristor of the previous same branch, which is connected by the anode to the connection point of this and the previous active resistance of the circuit, and such a branch is connected to the thyristor cathode of the previous same branch by the output of the active resistance ; the output of the excitation voltage sensor is connected to the inputs of two comparators of maximum action and a comparator of minimum action; thyristor control circuits, the cathodes of which are connected to the active resistances connected to the output of the field winding, connected to the positive pole of the exciter, are combined and connected to the output of the comparator of minimal action; the thyristor control circuit of the switch connected by the anode to the active resistance connected to the output of the field winding connected to the positive pole of the exciter is connected to the output of the first comparator of maximum action; block contacts of the circuit breaker are connected to the input of the first logic element of the type "NOT" and the input reset binary m-bit counter; the output of the first logic element of the type “NOT”, the output of the second logic element of the type “NOT” and the output of the second maximum comparator are connected to different inputs of the logic element of the type “AND”, the output of which is connected to the non-inverting input of the binary m-bit counter; the involved outputs of the binary m-bit counter are connected to the corresponding inputs of the binary code decoder, the outputs of which are connected to the control circuits of the thyristors of the field damping device in the order corresponding to the turn-on sequence of the thyristors of the branches containing the thyristor connected in series and the active resistance in parallel with which a capacitor is connected; the input of the second logical element of type "NOT" is connected to the output of the nth (last) bit of the binary code decoder.

The magnetic field damping device of the field winding 1 connected to the exciter 2 of the excitation system (Fig. 5) comprises a circuit breaker 3 connected in series with the field winding, a power part 4 connected in parallel with the field winding. The device contains a field voltage sensor 5, to the output of which through the inputs of the logic unit 6 are connected a comparator 7 of the minimum action (Fig.6) and comparators of the maximum action 8 and 9. The output of the comparator 7 is connected simultaneously to the control circuits of the thyristors 10 and 11, and the output of the comparator 8 connected to the control circuit of the thyristor 12. The output of the comparator 9, the output of the logic element 13 of the type “NOT” and the output of the logic element 14 of the type “NOT” are connected to different inputs of the logical element 15 of the type “AND”, the output of which is connected to a non-inverting input m-bit binary counter 16 [2]. The block contacts of the circuit breaker 3 are connected simultaneously with the input of the logic element 13 of the type "NOT" and with the reset input of the counter 16. The involved outputs of the counter 16 are connected to different inputs of the binary signal decoder 24 [2]. The number of outputs of the binary m-bit counter 16 is associated with the number of outputs of the decoder 24 by the ratio

m≥log ₂ n,

where n is the number of steps of the field suppression device (n≥2, integer value);

m is the bit capacity of the counter (integer value).

For the case of four stages of the device (n = 4), the bit width of the counter 16 will be greater than or equal to two (m≥2). To date, binary counters with a minimum capacity of four are available. Therefore, for the case of four stages of a field blanking device, a binary four-digit counter is used.

The control circuit of the thyristors of the power part 4 are connected to the outputs of the decoder 24 in the following order (Fig.6):

1st output - to the thyristor 17 control circuit;

2nd output - to the control circuit of the thyristor 25;

3rd output - to the thyristor control circuit 26.

The 4th output of the decoder is connected to the input of the logic element 14 of the type "NOT".

In the case where the number of stages of the field suppression device is n, the thyristor control circuit of the first branch of the field suppression device that is included in the operation, which contains the thyristor and active resistance, is connected in parallel with the capacitor to the first output of the decoder 24. The thyristor control circuits of other similar branches are connected to the inputs of the binary signal decoder 24 in the order corresponding to the sequence of their inclusion, the n-1st output of the decoder 24 in this case is connected to the thyristor control circuit of such a branch, which is turned on last (n-th), and its nth output is connected to the input of the logic element 14 of the type "NOT".

The power part 4 (Figure 5) contains four series-connected active resistance 19, 18, 27 and 28; between the resistances 18 and 19, two countercurrently connected parallel thyristors 10 and 12 are connected, and a contactor 20 is connected in parallel with these thyristors. Parallel to the part of the circuit containing the thyristor 10 connected in series, to the cathode of which is connected an active resistance 19 connected to the output of the field winding 1 connected to to the positive pole of the pathogen 2, a circuit is connected containing the thyristor 11 connected in series, to the cathode of which an active resistance 21 is connected, connected to the output of the field winding 1, sub connected to the positive pole of the pathogen 2. Parallel to the part of the circuit containing the thyristor 10 connected in series, to the anode of which an active resistance 18 is connected, a circuit is connected containing the thyristor 17 connected in series, to the cathode of which an active resistance 22 is connected, in parallel to which a capacitor 23. A circuit, containing a thyristor 25 connected in series and an active resistance 29 with a parallel capacitor 30, the thyristor anode is connected to the connection point of the resistances 27 and 28, and the output with the resistance 29 is connected to the cathode of the thyristor 17. A circuit containing a thyristor 26 connected in series and an active resistance 31 with a parallel capacitor 32, the thyristor anode is connected to the output of the excitation winding 1 connected to the negative pole of the exciter 2, and the resistance output 31 is connected to the cathode of the thyristor 25.

A device for damping the magnetic field of the field coil that implements the proposed method works as follows.

When the synchronous machine is operating, the voltage at the terminals of the field winding 1 is always higher than the setting of EZ-1 of the comparator 7 of the minimum action, below the setting of EZ-2 of the comparator 8 of the maximum action and above the setting of EZ-3 of the comparator 9 of the maximum action (Fig.6). Therefore, at the output of logic block 6, there are no control signals for thyristors 10, 11, and 12, and at the output of comparator 9, the signal has a logic level of “1” (Fig. 7). The block contacts of switch 3 are closed. Therefore, the signal at the output of the logic element 13 of the type "NOT" has a logic level of "0", and at the input of the counter reset 16 is a logic level of "1". Thus, the signal at the output of the logical element 15 of the type "AND" has a logic level of "0", there are no signals at all outputs of the counter 16, and the output at the output of the logic element 14 of the type "NOT" has a logic level of "1". At all outputs of the binary signal decoder 24 signals have a logic level of "0". All thyristors in the power part 4 are in the closed state, and the contacts of the contactor 20 are open.

The signal from the voltage sensor 5 is fed to the comparators 7 and 9. When the signal for blanking the field arrives, the relay protection of the machine opens the switch 3, which leads to a change in sign and a sharp increase in the voltage value on the field winding 1, as well as to the disappearance of the signal at the counter reset input 16 and the appearance of the signal at the output of the logic element 13 of the type "NOT". When this voltage becomes less than the setpoint EZ-1 of the comparator 7 of the minimum action, the signal at its output will have a logic level of “1” (Fig. 7, time t1), which will turn on the thyristors 10 and 11 and close the excitation current by resistance 28 , 27, 18, 19 and 21. The voltage on the field winding 1 is equal to the product of the field current and the resistance of the power part 4. As the magnetic field energy decreases, the field winding 1 due to its dissipation in the active resistances of the power part 4 decreases and the output voltage x field winding 1. When the value of this voltage becomes higher than the setting level of EZ-3 of comparator 9, a signal will appear at its output, which will lead to the appearance of a signal at the output of logic element 15 of type “I”, as a result of which the signal will have a output of zero discharge logical level “1” (Fig. 7, Q0, time t2). A signal will appear at the first output of the binary signal decoder 24, which will turn on the thyristor 17 in the power part 4. As a result, the voltage at the terminals of the excitation winding 1 is again increased to a value that is acceptable under the conditions of isolation operation. As the energy of the magnetic field of the field winding 1 decreases, the voltage at its terminals decreases, which leads to the operation of the comparator 9 and the appearance of a second pulse at the input of the counter 16 (Fig. 7, time t3). In this case, the signal at the output of the zero discharge of the counter 16 disappears, a signal appears at its output of the first discharge (Q1) and, as a result, at the second output of the binary signal decoder 24. This leads to the inclusion of the thyristor 25 in the power part 4 and an increase in the voltage on the field winding 1. When the third signal from the comparator 9 appears, 15 will work and give a signal to the input of the counter 16, at the output of the zero and first bits of which signals will appear (Fig. 7, time t4). This will lead to the appearance of a signal at the third output of the binary signal decoder 24, the inclusion of the thyristor 26 in the power part 4 and an increase in the voltage on the field winding 1. At the next increase in voltage to the setting level, a signal appears at the output of the comparator 9, which will lead to the disappearance of the signals at the zero outputs and the first bits of the counter 16 and the appearance of the signal at the output of its second discharge (Fig.7, Q2, time t5). As a result, a signal appears on the fourth output of the binary signal decoder 24 and the signal of the logic element 14 of the “NOT” type disappears, which will lead to the termination of the power part 4. Field blanking is completed at the fourth stage of the resistance of the power part 4. The device is returned to its original state by applying a signal from the block contacts of the switch 3 of the excitation circuit at the time of its inclusion. In this case, the counter 16 is reset, and the logical “0” from the output 13 blocks the operation of the element 15 (Fig. 7, time t6). The circuit is in its original state.

Thus, the proposed method and device for damping the magnetic field of the excitation winding of a synchronous machine can reduce the time of damping the field and bring it closer to that which will be with the use of AGP, while maintaining the simplicity of the device, and also realize on its basis the functions of a thyristor spark gap and a self-synchronization resistor of synchronous generators . This allows you to use existing elements of the excitation systems of synchronous generators, which leads to its cost reduction compared to the use of other field suppression devices.

Information sources

1. Bron O.B. Magnetic field quenching machines. - M.-L .: Gosenergoizdat, 1961 .-- 138 p. - (Library on automation. Issue 34).

2. Gorshkov B.I. Elements of electronic devices: a directory. - M .: Radio and communications, 1988 .-- 176 p.

Claims (3)

1. The method of damping the magnetic field of the field winding of a synchronous machine, which consists in dissipating the energy of the magnetic field of the field winding on an active linear resistance, characterized in that they additionally measure the voltage at the terminals of the field winding, and compare it with the set point, when the measured voltage is reduced to the set point voltage, active resistance is increased by one step to a value equal to the ratio of voltage, the maximum permissible under the operating conditions of the insulation of the field winding, to the value of a, at which the voltage reaches the setpoint. 2. A device for damping the magnetic field of the excitation winding of a synchronous machine, comprising a circuit breaker connected in series with the excitation winding, as well as a voltage sensor connected in parallel with the excitation winding and a circuit consisting of series-connected active resistance and a switch containing two parallel counter-connected thyristors and connected in parallel contactor, characterized in that the specified resistance is made of two identical parts and the switch is on between them, and parallel to the part of this circuit, consisting of a series-connected switch and active resistance connected to the output of the field winding connected to the positive pole of the exciter, a branch is connected containing series-connected active resistance connected to the output of the field winding connected to the positive pole of the exciter , and a thyristor, the cathode of which is connected to this resistance, parallel to the circuit containing the switch and the active resistor in series resistance connected to the output of the excitation winding connected to the negative pole of the exciter, a branch is connected containing serially connected thyristor, the anode of which is connected to the output of the excitation winding connected to the negative pole of the exciter, and another active resistance in parallel with which a capacitor is connected, the output of the excitation voltage sensor connected to the inputs of two maximum action comparators and a minimum action comparator, thyristor control circuit, the anodes of which are connected values to the active resistance connected to the output of the field winding connected to the negative pole of the exciter, combined and connected to the output of the comparator of the minimum action, the thyristor control circuit of the field suppression device connected by the cathode to the active resistance connected to the output of the field winding connected to the negative pole of the exciter, connected to the output of the first maximum action comparator, the block contacts of the circuit breaker are connected to the input of the first logical an element of type NOT and a binary four-digit counter reset input, output of a first logical element of type NOT, output of a second logical element of type NOT, and output of a second maximum comparator connected to different inputs of a logic element of type I, the output of which is connected to a non-inverting input of a binary four-bit counter, zero output the discharge of a binary four-digit counter connected to the thyristor control circuit of the field suppression device connected by the anode to the output of the field winding, connected To the negative pole of the pathogen, the input of the second logical element of the type is NOT connected to the output of the first bit of the binary four-digit counter. 3. A device for damping the magnetic field of the excitation winding of a synchronous machine, comprising a circuit breaker connected in series with the excitation winding, as well as a voltage sensor connected in parallel with the excitation winding and a circuit consisting of series-connected active resistance and a switch containing two parallel counter-connected thyristors and connected in parallel contactor, characterized in that the specified resistance is made of "n" equal parts, the switch is connected between the first and second part of the active resistance, counting from the output of the field winding connected to the positive pole of the pathogen, and parallel to the part of this circuit consisting of series-connected commutator and active resistance connected to the output of the field winding connected to the positive pole of the pathogen, a branch is connected containing series-connected active resistance connected to the output of the field winding connected to the positive pole of the pathogen, and a thyristor, cathode connected to this resistance; a branch containing a thyristor and other active resistance connected in parallel, a capacitor connected in parallel, the thyristor anode is connected to the connection point of the second and third parts of the specified active resistance, counting from the excitation winding connected to the positive pole of the exciter, and the output of the other active resistance is connected to the output of the first part of the active resistance connected simultaneously with the switch and with the output of the field winding connected to the positive field for the pathogen, subsequent similar branches are connected in parallel to each part of the circuit containing the active resistance and the thyristor of the previous same branch, which is connected by the anode to the connection point of this and the previous active resistance of the circuit, and this branch is connected to the thyristor cathode of the previous same branch by the output of the active resistance , the output of the excitation voltage sensor is connected to the inputs of two comparators of maximum action and a comparator of minimum action; thyristor control circuits, the cathodes of which are connected to active resistances connected to the excitation winding terminal connected to the positive pole of the exciter, are connected and connected to the output of the minimum comparator, the switch thyristor control circuit connected by the anode to the active resistance connected to the excitation terminal connected to to the positive pole of the pathogen, connected to the output of the first comparator of the maximum action, block contacts of the circuit breaker are outputted from the input of the first logical element of type NOT and the input of the reset of the binary m-bit counter, the output of the first logical element of type NOT, the output of the second logical element of type NOT and the output of the second comparator of maximum action are connected to different inputs of the logical element of type AND, the output of which is connected to a non-inverting the input of the binary m-bit counter, the involved outputs of the binary m-bit counter are connected to the corresponding inputs of the binary code decoder, the outputs of which are connected to the control circuits eniya thyristors field blanking device in the order of priority of thyristors branches comprising series connected thyristor and the resistance, is connected parallel to the capacitor input type second logic element output is coupled to the n-th (last) discharge binary decoder.

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