Inter-end operation impact test device of high-voltage resistor

Abstract

The utility model provides an end-to-end operation impact test device for a high-voltage resistor. The end-to-end operation impact test device is mainly used for solving the technical problem that an existing impact voltage generator cannot carry out an end-to-end operation impact test on the high-voltage resistor. The circuit comprises a wave tail resistor, a main capacitor, a wave head resistor, a wave head capacitor, a capacitive voltage divider and a wave modulation inductor. Wherein the two ends of the capacitive voltage divider serve as measuring ends, are connected with the high-voltage resistor in parallel and are used for applying rapidly changing high-voltage impact to the two ends of the high-voltage resistor. By adjusting the inductance value, the test device can output a standard waveform meeting the requirement, so that the inter-end operation impact test of the high-voltage resistor with the resistance value is completed.

Description

Technical Field

[0001] The utility model relates to an inter-terminal test device for high-voltage resistors, and particularly to an inter-terminal switching impulse test device for high-voltage resistors. Background Art

[0002] High-voltage electrical equipment needs to be subjected to inter-terminal and terminal-to-ground switching impulse tests to evaluate its ability to withstand switching overvoltage impulses in the power system. The inter-terminal switching impulse test is to apply a rapidly changing high-voltage impulse at both ends of a high-voltage resistor. In the prior art, an impulse voltage generator is generally used to output a standard switching waveform and apply a rapidly changing high-voltage impulse to test the insulation performance of high-voltage electrical equipment.

[0003] As a high-voltage electrical equipment, the inter-terminal impedance of a high-voltage resistor is not infinite, but has a certain resistance value; currently, the existing impulse voltage generators cannot adjust the standard switching waveform for non-infinite loads. Therefore, it is urgent to upgrade and optimize the existing impulse voltage generators to create a test device that can perform inter-terminal switching impulse tests on high-voltage resistors. Summary of the Utility Model

[0004] The purpose of the utility model is to solve the technical problem that the existing impulse voltage generator cannot perform inter-terminal switching impulse tests on high-voltage resistors, and to propose an inter-terminal switching impulse test device for high-voltage resistors.

[0005] To solve the above technical problems, the technical solution provided by the utility model is as follows:

[0006] An inter-terminal switching impulse test device for high-voltage resistors, characterized in that it includes a tail-wave resistor, a main capacitor, a front-wave resistor, a front-wave capacitor, a capacitive voltage divider, and a wave-shaping inductor;

[0007] A discharge gap is provided between one end of the tail-wave resistor and one end of the main capacitor, and the other end of the tail-wave resistor and the other end of the main capacitor are grounded;

[0008] One end of the front-wave resistor is connected to one end of the tail-wave resistor, and the other end is connected to one end of the wave-shaping inductor; the high-voltage end of the capacitive voltage divider is connected to the other end of the wave-shaping inductor, and the low-voltage end of the capacitive voltage divider is grounded; the front-wave capacitor is connected in parallel across the front-wave resistor;

[0009] The high-voltage end of the capacitive voltage divider is connected to the high-voltage end of the high-voltage resistor to be tested through a high-voltage lead, and the low-voltage end of the high-voltage resistor to be tested is grounded.

[0010] Further, the wave-shaping inductor is a hollow inductor.

[0011] Further, the calculation formula for the external dimension of the wave-shaping inductor is: L = (d 2n 2 ) / (1 + 0.45d), where L represents the inductance value of the wave - tuning inductor, d represents the diameter of the coil, and n represents the number of turns of the coil.

[0012] Furthermore, the inductive reactance of the wave - tuning inductor is determined by the following formula:

[0013] T f = 3.24(R f + XL)×C1×C2 / (C1 + C2);

[0014] Among them, T f is the required value of the wavefront time of the output measured - end voltage waveform, 3.24 is a specific parameter of the impulse voltage generator, C1 represents the capacitance value of the main capacitor, C2 represents the capacitance value of the equivalent capacitance of the capacitive voltage divider, R f represents the resistance value of the wave - front resistor, and XL represents the inductive reactance of the wave - tuning inductor.

[0015] Furthermore, the calculation formula for the inductive reactance XL of the wave - tuning inductor is: XL = 2πfL; where f represents the frequency of the alternating current, and L represents the inductance value of the wave - tuning inductor.

[0016] Advantages of the present utility model:

[0017] 1. The present utility model includes a wave - tail resistor, a main capacitor, a wave - front resistor, a wave - front capacitor, a capacitive voltage divider, and a wave - tuning inductor; both ends of the capacitive voltage divider are used as the measurement ends and are connected in parallel with the high - voltage resistor, and are used to apply a rapidly changing high - voltage impulse to both ends of the high - voltage resistor. By adjusting the inductance value of the wave - tuning inductor, the test device can output a standard waveform that meets the requirements, thereby completing the inter - terminal switching impulse test on the high - voltage resistor with resistance value.

[0018] 2. The wave - tuning inductor of the present utility model adopts an air - core inductor, and its specific dimensions can be calculated according to the inductance value for manufacturing, which has the characteristic of convenience.

[0019] 3. The numerical calculation of the wave - tuning inductor of the present utility model is simple and can be adjusted according to the specific situation of the circuit, thereby improving the accuracy of the output waveform.

[0020] 4. The structure of the present utility model is simple, and the operation is easy, which is convenient for the test personnel to execute. Description of the Drawings

[0021] Figure 1 is a schematic diagram of an embodiment of an inter - terminal switching impulse test device for a high - voltage resistor of the present utility model.

[0022] Description of the Reference Numerals:

[0023] 1. Tail wave resistor; 2. Main capacitor; 3. Front wave resistor; 4. Front wave capacitor; 5. Capacitive voltage divider; 6. High-voltage resistor; 7. Wave-shaping inductor. Specific implementation manner

[0024] The present utility model will be further described below in conjunction with the accompanying drawings and embodiments.

[0025] An inter-terminal switching impulse test device for a high-voltage resistor of the present utility model, as Figure 1 shown, includes a tail wave resistor 1, a main capacitor 2, a front wave resistor 3, a front wave capacitor 4, a capacitive voltage divider 5 and a wave-shaping inductor 7;

[0026] The tail wave resistor 1 is connected in parallel with the main capacitor 2. A discharge gap is provided between one end of the tail wave resistor 1 and one end of the main capacitor 2. The other end of the tail wave resistor 1 and the other end of the main capacitor 2 are grounded; the front wave resistor 3, the wave-shaping inductor 7 and the capacitive voltage divider 5 are connected in series in sequence. One end of the front wave resistor 3 is connected to one end of the tail wave resistor 1, and the other end is connected to one end of the wave-shaping inductor 7; the high-voltage end of the capacitive voltage divider 5 is connected in series with the other end of the wave-shaping inductor 7, and the low-voltage end of the capacitive voltage divider 5 is grounded. The front wave capacitor 4 is connected in parallel across the two ends of the front wave resistor 3. The two ends of the capacitive voltage divider 5 are used as output measurement terminals and are connected in parallel with the high-voltage resistor 6. Among them, the high-voltage lead of the high-voltage end of the capacitive voltage divider 5 was originally connected to the inside of the impulse voltage generator. In the present utility model, the high-voltage lead of the capacitive voltage divider 5 is connected to the high-voltage end of the high-voltage resistor 6.

[0027] According to the standard switching impulse voltage waveform parameters specified by the International Electrotechnical Commission and national standards: the front wave time T f = 250 μs ± 20%; the tail wave time T t = 2500 μs ± 60%; using an existing impulse voltage generator to conduct an inter-terminal switching impulse test on the high-voltage resistor 6, the actually output waveform parameters are: the front wave time T f = 1.5 μs; the half-peak time T t = 55 μs; due to the certain resistance value of the high-voltage resistor 6, it has an impact on the circuit, resulting in a large difference between the actual waveform parameters and the standard waveform parameters.

[0028] The calculation formula for the front wave time is: T f = 3.24(R f + XL)×C1×C2 / (C1 + C2); where 3.24 is a fixed parameter of the impulse voltage generator, C1 represents the capacitance value of the main capacitor 2, C2 represents the equivalent capacitance value of the capacitive voltage divider 5, R f represents the resistance value of the front wave resistor 3, and XL represents the inductive reactance of the wave-shaping inductor 7;

[0029] It can be seen from the calculation formula of the front wave time that by increasing C1, C2, Rf Both L and XL can increase the wavefront time; by changing the series-parallel connection method, C1 can be increased. However, since the values of each capacitor are fixed, changing the series capacitors to parallel ones can only increase C1 by about 2.5 times to a certain extent, which is difficult to achieve the expected goal. When increasing C2, due to the high voltage level of the impulse voltage generator, it is required that the equivalent capacitance of the additional capacitive voltage divider 5 and the insulation level of the load capacitance match the high voltage level, otherwise it cannot withstand the action of high voltage, but this is accompanied by an increase in cost. The wavefront time can also be adjusted by increasing the resistance value R of the wavefront resistor 3 f to adjust the wavefront time. However, the wavefront resistor 3 and the high-voltage resistor 6 are in a voltage-dividing relationship. When the resistance value R of the wavefront resistor 3 f differs greatly from the resistance value Rs of the high-voltage resistor 6, the wavefront resistor 3 will bear more voltage division; this greatly reduces the efficiency of checking the insulation level of the high-voltage resistor 6, which goes against the purpose of the switching impulse test between the terminals of the high-voltage resistor 6.

[0030] Increasing the inductance can increase the wavefront time. The inductive reactance XL of the wave-shaping inductor 7 is calculated by the formula: XL = 2πfL; where f represents the frequency of the alternating current and L represents the inductance value of the wave-shaping inductor 7. From the calculation formula of the wavefront time T f = 3.24(R f + XL)×C1×C2 / (C1 + C2), the inductive reactance value that meets the wavefront time T f requirement can be calculated, and thus the inductance of the required wave-shaping inductor 7 can be obtained.

[0031] In this embodiment, the wave-shaping inductor 7 uses an air-core inductor, and the calculation formula for its external dimensions is: L = (d 2 n 2 ) / (1 + 0.45d), where d represents the diameter of the coil and n represents the number of turns of the coil.

[0032] In the simulation software, a simulation model is built according to the Figure 1 shown circuit. Taking the value of the wave-shaping inductor 7 obtained from theoretical calculation and other parameters as input conditions, the switching impulse test simulation calculation between the terminals is carried out. According to the standard waveform obtained from the simulation, it is verified whether the inductance value calculated theoretically reaches the expected effect. If it does not reach the expected effect, the inductance can be adjusted appropriately. Finally, an air-core inductor is made according to the most suitable inductance value obtained from the simulation, and it is connected between the impulse voltage generator and the high-voltage resistor 6 for the switching impulse test.

Claims

1. A terminal operation impact test device for a high voltage resistor, characterized in that: It includes a wave tail resistor (1), a main capacitor (2), a wave head resistor (3), a wave head capacitor (4), a capacitive voltage divider (5) and a wave modulation inductor (7); A discharge gap is provided between one end of the wave tail resistor (1) and one end of the main capacitor (2), and the other end of the wave tail resistor (1) and the other end of the main capacitor (2) are grounded; One end of the wave head resistor (3) is connected to one end of the wave tail resistor (1), and the other end is connected to one end of the wave modulation inductor (7); the high voltage end of the capacitive voltage divider (5) is connected to the other end of the wave modulation inductor (7), and the low voltage end of the capacitive voltage divider (5) is grounded; the wave head capacitor (4) is connected in parallel to the two ends of the wave head resistor (3); The high voltage end of the capacitive voltage divider (5) is connected to the high voltage end of the high voltage resistor (6) to be measured via a high voltage lead, and the low voltage end of the high voltage resistor (6) to be measured is grounded.

2. The device for testing the terminal-to-terminal operation impact of a high-voltage resistor according to claim 1, characterized in that: The wave modulation inductor (7) is a hollow inductor.

3. The device for testing the terminal-to-terminal operation impact of a high-voltage resistor according to claim 2, characterized in that: The calculation formula of the outer dimensions of the modulating inductor (7) is: L = (d 2 n 2 ) / (1+0.45d), where L represents the inductance of the modulation inductor (7), d represents the diameter of the coil, and n represents the number of turns of the coil.

4. The device for testing the terminal-to-terminal operation impact of a high-voltage resistor according to claim 3, characterized in that: The inductive reactance of the modulation inductor (7) is determined by the following formula: T f =3.24(R f +XL)×C1×C2 / (C1+C2); Among them, T f is the wavefront time requirement of the output voltage waveform at the measuring end, 3.24 is the specific parameter of the impulse voltage generator, C1 represents the capacitance of the main capacitor (2), C2 represents the capacitance of the equivalent capacitance of the capacitive voltage divider (5), R f represents the resistance of the wave head resistor (3), and XL represents the inductive reactance of the wave modulation inductor (7).

5. The device for testing the terminal-to-terminal operation impact of a high-voltage resistor according to claim 4, characterized in that: The calculation formula of the inductive reactance XL of the modulating inductor (7) is: XL=2πfL; wherein f represents the frequency of the alternating current, and L represents the inductance value of the modulating inductor (7).

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