A controllable starting type twelve-pulse rectifier short-circuit impulse generator excitation system

Abstract

The present invention discloses a controllable starting type twelve-pulse rectifier short-circuit impulse generator excitation system. The present invention uses a twelve-pulse rectifier device to provide excitation current for the rotor winding of the short-circuit impulse generator, effectively reducing the harmonic interference of the excitation system on the power grid, the three-phase AC voltage is connected to the high-voltage switch, and the AC power is provided to the twelve-pulse rectifier device after being stepped down by the secondary double-coil d0-y11 step-down transformer, the twelve-pulse trigger device provides a trigger pulse for the twelve-pulse rectifier device, and the starting resistance control device is used to control the switch device, so as to realize the input and cut-off of the starting resistance as needed, ensure the smooth starting of the short-circuit impulse generator, and effectively solve the problem of serious heating of the starting resistance when the short-circuit impulse generator is running for a long time and multiple short-circuit impulse generators are tested in parallel, so as to realize the short-circuit test of the short-circuit impulse generator with a higher current level.

Description

Technical Field

[0001] The invention belongs to the field of large-capacity short-circuit impulse generators, and in particular relates to a controllable starting twelve-pulse rectifier short-circuit impulse generator excitation system. Background Art

[0002] When a large-capacity short-circuit impulse generator is running under a sudden short-circuit condition, it outputs a huge instantaneous short-circuit current and provides a test current for the high-voltage conversion device test product. The short-circuit impulse generator excitation system is a separate excitation method, which provides a DC excitation power supply to the short-circuit impulse generator rotor excitation winding. The short-circuit impulse generator excitation system currently widely used adopts a six-pulse thyristor fully controlled rectifier device and an excitation system with a long-term connection to the starting resistor. This structure provides an effective conduction current for the thyristor through the starting resistor, and provides a stable excitation current for the short-circuit impulse generator through the six-pulse thyristor fully controlled rectifier device, ensuring that the short-circuit impulse generator starts smoothly and operates reliably.

[0003] However, with the improvement of grid power quality requirements and the gradual increase in the current required by high-voltage conversion device test products, the traditional impulse generator excitation system will have the following problems: First, multiple groups of high-power six-pulse rectifier circuits work at the same time, generating a large amount of harmonic current that flows into the grid, causing serious interference to the grid; Second, the short-circuit current provided by a single short-circuit impulse generator is not enough to meet the current required by the conversion device test product, and multiple short-circuit impulse generators need to be connected in parallel to provide a larger current. The parallel operation of multiple short-circuit impulse generators requires the short-circuit generators to be started in turn to the no-load rated condition before conducting a parallel short-circuit test. Therefore, the excitation system is energized for a longer time, and the starting resistor is connected in parallel in the rotor circuit for a long time to withstand the current, which will cause severe heating and affect the stability of the excitation system. Summary of the invention

[0004] In view of this, the purpose of the present invention is to disclose a controllable starting twelve-pulse rectification short-circuit impulse generator excitation system that effectively reduces the harmonic interference of the excitation system to the power grid through the twelve-pulse rectification principle, and uses the starting resistor to disconnect the circuit to solve the problem of starting resistor heating under long-term operation of the excitation system. The technical solution of the present invention is: it consists of a high-voltage switch, a secondary double-coil d0-y11 step-down transformer, a twelve-pulse rectification device, a starting resistor, a switch device, a demagnetization device, a short-circuit impulse generator rotor winding, a twelve-pulse trigger device, and a starting resistor control device. The three-phase AC voltage is connected to the secondary double-coil d0-y11 step-down transformer through a high-voltage switch. The secondary double-coil d0-y11 step-down transformer outputs two sets of three-phase AC voltages with a phase difference of 30° and is connected to the AC side of the twelve-pulse rectifier. The twelve-pulse trigger device sends pulses to the control side of the twelve-pulse rectifier. The short-circuit impulse generator terminal voltage and the short-circuit test starting voltage threshold enter the starting resistor control device, and the starting resistor control device outputs to the switch device. The starting resistor is connected in series with the switch device, and then connected to the DC output of the twelve-pulse rectifier in parallel with the demagnetization device and the short-circuit impulse generator rotor winding to form a whole.

[0005] In the above-mentioned controllable start-up twelve-pulse rectifier short-circuit impulse generator excitation system, the twelve-pulse rectifier device is composed of a three-phase thyristor fully controlled rectifier double bridge group A, a three-phase thyristor fully controlled rectifier double bridge group B, and a smoothing reactor with an intermediate tap. The two sets of outputs of the secondary double-coil d0-y11 step-down transformer are respectively connected to the AC side of the three-phase thyristor fully controlled rectifier double bridge group A and the three-phase thyristor fully controlled rectifier double bridge group B. The three-phase thyristor fully controlled rectifier double bridge The DC positive output of group A and the DC positive output of the three-phase thyristor fully controlled rectifier double bridge group B are connected in series via a smoothing reactor with a center tap, and the center tap of the smoothing reactor with a center tap is led out as the DC positive output of the twelve-pulse rectifier device, and the DC negative output of the three-phase thyristor fully controlled rectifier double bridge group A and the DC negative output of the three-phase thyristor fully controlled rectifier double bridge group B are connected together and led out as the DC negative output of the twelve-pulse rectifier device.

[0006] In the above-mentioned controllable starting twelve-pulse rectifier short-circuit impulse generator excitation system, the starting resistance control device is composed of an analog quantity acquisition module, a setting module, a parameter integration module, and a switch control output module. The short-circuit impulse generator terminal voltage enters the parameter integration module after being processed by the analog quantity acquisition module, and the short-circuit test starting voltage threshold enters the parameter integration module through the setting module. The output of the parameter integration module enters the switch control output module, and the output of the switch control output module is the control signal output by the starting resistance control device.

[0007] In the above-mentioned controllable start-type twelve-pulse rectifier short-circuit impulse generator excitation system, the switch device is composed of a control signal receiving module, a low-voltage to high-voltage conditioning module, and a starting switch module. The control signal receiving module receives the control signal output by the starting resistance control device, the output of the control signal receiving module is connected to the low-voltage to high-voltage conditioning module, the output of the low-voltage to high-voltage conditioning module is connected to the starting switch module, and the output of the starting switch module is the output of the switch device.

[0008] Compared with the prior art, the present invention has the following beneficial effects:

[0009] 1. The present invention can effectively reduce the harmonic interference caused by the short-circuit impulse generator excitation system to the power grid. The twelve-pulse rectifier device in the present invention can improve the 5th, 7th and 9th harmonics caused by the traditional excitation system, thereby reducing the harmonic interference caused by the traditional short-circuit impulse generator excitation system to the power grid.

[0010] 2. The present invention can realize parallel test of multiple short-circuit impulse generators and provide a larger short-circuit test current for the conversion device test product. The switch device in the present invention can disconnect the starting resistor, effectively avoiding the problem of heating and burning caused by long-term pressure on the starting resistor, so that a single short-circuit impulse generator can operate for a long time under no-load rated conditions, and wait for other short-circuit impulse generators to start before conducting multiple parallel tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The figure is a detailed diagram of the excitation system of a controllable starting twelve-pulse rectifier short-circuit impulse generator.

[0012] Figure 2 This is a detailed diagram of the twelve-pulse rectifier device.

[0013] Figure 3 This is a detailed diagram of the starting resistance control device.

[0014] Figure 4 Detailed diagram of the switchgear.

[0015] Explanation of the marks in the figure: 1-high-voltage switch; 2-secondary double-coil d0-y11 step-down transformer; 3-twelve-pulse rectifier; 4-starting resistor; 5-switch device; 6-demagnetization device; 7-short-circuit impact generator rotor winding; 8-twelve-pulse trigger device; 9-starting resistor control device; 10-three-phase thyristor fully controlled rectifier double bridge group A; 11-three-phase thyristor fully controlled rectifier double bridge group B; 12-smoothing reactor with intermediate tap; 13-analog acquisition module; 14-setting module; 15-parameter integration module; 16-switch control output module; 17-control signal receiving module; 18-low-voltage to high-voltage conditioning module; 19-dynamic switch module. DETAILED DESCRIPTION

[0016] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0017] like Figure 1 As shown, a controllable starting type twelve-pulse rectifier short-circuit impulse generator excitation system is composed of a high-voltage switch 1, a secondary double-coil d0-y11 step-down transformer 2, a twelve-pulse rectifier device 3, a starting resistor 4, a switch device 5, a demagnetization device 6, a short-circuit impulse generator rotor winding 7, a twelve-pulse trigger device 8, and a starting resistor control device 9. The three-phase AC voltage is connected to the secondary double-coil d0-y11 step-down transformer 2 through the high-voltage switch 1, and the secondary double-coil d0-y11 step-down transformer 2 outputs two sets of three-phase AC voltages with a phase difference of 30° and is connected to the AC side of the twelve-pulse rectifier device 3. The twelve-pulse trigger device 8 sends pulses to the control side of the twelve-pulse rectifier device 3, and the short-circuit impulse generator terminal voltage and the short-circuit test starting voltage threshold enter the starting resistor control device 9, which outputs to the switch device 5. The starting resistor 4 is connected in series with the switch device 5, and then connected in parallel with the demagnetization device 6 and the short-circuit impulse generator rotor winding 7 to the DC output of the twelve-pulse rectifier device 3 to form a whole. The working steps of the excitation system during the short-circuit impulse generator test are as follows: the high-voltage switch 1 is closed, and the three-phase AC voltage passes through the high-voltage switch 1 and is stepped down by the secondary double-coil d0-y11 step-down transformer 2 to provide AC power for the twelve-pulse rectifier 3. The starting resistor control device 9 performs software processing according to the terminal voltage of the short-circuit impulse generator and the short-circuit test starting voltage threshold, and outputs a control signal to the switch device 5. The switch device 5 controls the input and output of the starting resistor 4 according to the received control signal to ensure that the generator starts smoothly and the starting resistor 4 does not heat up. The twelve-pulse trigger device 8 outputs pulses to the twelve-pulse rectifier 3 according to the test requirements. The twelve-pulse rectifier 3 outputs DC to the rotor winding 7 of the short-circuit impulse generator, so that the short-circuit impulse generator enters the no-load rated state. At this time, the short-circuit test of a single short-circuit impulse generator can be directly carried out. If a higher level of short-circuit current is required, multiple short-circuit impulse generators need to be started to the no-load rated state according to the above steps, and then the short-circuit test of multiple short-circuit impulse generators in parallel is carried out.

[0018] like Figure 2As shown, the twelve-pulse rectifier device 3 is composed of a three-phase thyristor fully controlled rectifier double bridge group A10, a three-phase thyristor fully controlled rectifier double bridge group B11, and a smoothing reactor 12 with an intermediate tap. The two output groups of the secondary double-coil d0-y11 step-down transformer 2 are respectively connected to the AC side of the three-phase thyristor fully controlled rectifier double bridge group A10 and the three-phase thyristor fully controlled rectifier double bridge group B11. The DC positive output of the three-phase thyristor fully controlled rectifier double bridge group A10 is connected to the AC side of the three-phase thyristor fully controlled rectifier double bridge group B11. The DC positive outputs of the three-phase thyristor fully controlled rectifier double bridge group B12 are connected in series via a smoothing reactor 12 with a middle tap, and the middle tap of the smoothing reactor 12 with a middle tap is led out as the DC positive output of the twelve-pulse rectifier device 3. The DC negative output of the three-phase thyristor fully controlled rectifier double bridge group A10 and the DC negative output of the three-phase thyristor fully controlled rectifier double bridge group B11 are connected together and led out as the DC negative output of the twelve-pulse rectifier device 3. During the short-circuit impact generator set test, the high-voltage switch 1 is closed, and the three-phase AC voltage enters the AC side of the twelve-pulse thyristor fully-controlled rectifier bridge 3 through the secondary double-coil d0-y11 step-down transformer 2. The twelve-pulse trigger device 8 sends pulses to the control side of the twelve-pulse rectifier 3 according to the actual working conditions. The smoothing reactor 12 with an intermediate tap absorbs the instantaneous difference in line voltage between the two groups of three-phase thyristor fully-controlled rectifier double bridge groups, ensuring that the twelve-pulse rectifier 3 outputs a stable twelve-pulse voltage, effectively reducing the harmonic interference of the system to the power grid.

[0019] like Figure 3 As shown, the starting resistance control device 9 is composed of an analog quantity acquisition module 13, a setting module 14, a parameter integration module 15, and a switch control output module 16. The terminal voltage of the short-circuit impulse generator is processed by the analog quantity acquisition module 13 and enters the parameter integration module 15. The short-circuit test starting voltage threshold enters the parameter integration module 15 through the setting module 14. The output of the parameter integration module 15 enters the switch control output module 16. The switch control output module 16 is the control signal output by the starting resistance control device 9. Before the short-circuit impulse generator test, the starting voltage threshold corresponding to the short-circuit test of different current levels is input into the setting module 14, and the setting module 14 enters the parameter integration module 15 after processing. During the starting process of the short-circuit impulse generator, the analog quantity acquisition module 13 samples the short-circuit impulse generator terminal voltage and enters the parameter integration module 15. The parameter integration module 15 processes the received value and outputs a control signal to the switch control output module 16. The signal of the switch control output module 16 is used as the output signal of the starting resistance control device 9 to ensure that the starting resistance control device 9 controls the switch device 5 according to the short-circuit test requirements of different current levels.

[0020] like Figure 4As shown, the switch device 5 is composed of a control signal receiving module 17, a low voltage to high voltage conditioning module 18, and a starting switch module 19. The control signal receiving module 17 receives the control signal output by the starting resistor control device 9, and the output of the control signal receiving module 17 is connected to the low voltage to high voltage conditioning module 18, and the output of the low voltage to high voltage conditioning module 18 is connected to the starting switch module 19. The output of the starting switch module 19 is the output of the switch device 5. During the unit startup process, the control signal receiving module 17 sends the control signal of the starting resistor control device 9 to the low voltage to high voltage conditioning module 18, and the low voltage to high voltage conditioning module 18 controls the on and off of the starting switch module 19, so as to realize the starting resistor being put into and disconnected as needed, and realize the starting resistor being the thyristor in the twelve-pulse rectifier 3. At the same time, it avoids the serious heating of the starting resistor due to long-term use, and improves the stability of the excitation system.

[0021] The present invention is applicable to the excitation system of a large-capacity short-circuit impulse generator, can effectively solve the problems existing in the traditional design scheme, and has the characteristics of high module integration, good stability, significant effect, etc.

[0022] Finally, the protection scope of the present invention is not limited to the above-mentioned embodiments. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the scope and spirit of the present invention. If these changes and modifications fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these changes and modifications.

Claims

1. A controllable starting twelve-pulse rectifier short-circuit impulse generator excitation system, characterized by: The invention comprises a high-voltage switch (1), a secondary double-coil d0-y11 step-down transformer (2), a twelve-pulse rectifier (3), a starting resistor (4), a switch device (5), a demagnetization device (6), a short-circuit impulse generator rotor winding (7), a twelve-pulse trigger device (8), and a starting resistor control device (9). The three-phase AC voltage is connected to the secondary double-coil d0-y11 step-down transformer (2) through the high-voltage switch (1). The secondary double-coil d0-y11 step-down transformer (2) outputs two sets of phase-phase A three-phase AC voltage with a difference of 30° is connected to the AC side of a twelve-pulse rectifier (3), a twelve-pulse trigger device (8) sends pulses to the control side of the twelve-pulse rectifier (3), a short-circuit impulse generator terminal voltage and a short-circuit test starting voltage threshold enter a starting resistor control device (9), the starting resistor control device (9) outputs to a switch device (5), a starting resistor (4) is connected in series with the switch device (5), and then connected in parallel with a demagnetization device (6) and a short-circuit impulse generator rotor winding (7) to the twelve-pulse rectifier. The DC output of the device (3) forms a whole, wherein the twelve-pulse rectifier device (3) is composed of a three-phase thyristor fully controlled rectifier double bridge group A (10), a three-phase thyristor fully controlled rectifier double bridge group B (11), and a smoothing reactor (12) with an intermediate tap, and the two groups of outputs of the secondary double-coil d0-y11 step-down transformer (2) are respectively connected to the AC side of the three-phase thyristor fully controlled rectifier double bridge group A (10) and the three-phase thyristor fully controlled rectifier double bridge group B (11), and the three-phase thyristor fully controlled rectifier double bridge group A (10) is connected to the AC side of the three-phase thyristor fully controlled rectifier double bridge group. The DC positive output is connected in series with the DC positive output of the three-phase thyristor fully controlled rectifier double bridge group B (11) via a smoothing reactor (12) with a middle tap, and the middle tap of the smoothing reactor (12) with a middle tap is led out as the DC positive output of the twelve-pulse rectifier (3), and the DC negative output of the three-phase thyristor fully controlled rectifier double bridge group A (10) is connected with the DC negative output of the three-phase thyristor fully controlled rectifier double bridge group B (11) to be led out as the DC negative output of the twelve-pulse rectifier (3).

2. According to claim 1, a controllable starting twelve-pulse rectifier short-circuit impulse generator excitation system is characterized by: The starting resistance control device (9) is composed of an analog quantity acquisition module (13), a setting module (14), a parameter integration module (15), and a switch control output module (16). The short-circuit impulse generator terminal voltage is processed by the analog quantity acquisition module (13) and enters the parameter integration module (15). The short-circuit test starting voltage threshold enters the parameter integration module (15) through the setting module (14). The output of the parameter integration module (15) enters the switch control output module (16). The output of the switch control output module (16) is the control signal output by the starting resistance control device (9).

3. The controllable start-up twelve-pulse rectifier short-circuit impulse generator excitation system according to claim 1 is characterized by: The switch device (5) is composed of a control signal receiving module (17), a low voltage to high voltage conditioning module (18), and a starting switch module (19); the control signal receiving module (17) receives a control signal output by a starting resistance control device (9); the output of the control signal receiving module (17) is connected to the low voltage to high voltage conditioning module (18); the output of the low voltage to high voltage conditioning module (18) is connected to the starting switch module (19); and the output of the starting switch module (19) is the output of the switch device (5).

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