Testing device for DC superposition harmonic voltage

Abstract

The utility model discloses a testing device for DC superposition harmonic voltage, and belongs to the technical field of electrical equipment testing. Comprising a voltage generating device of direct-current superposition harmonic voltage, electrical equipment to be tested and a broadband resistance-capacitance voltage divider. The voltage generating device of the direct current superposition harmonic voltage comprises a double-side voltage doubling rectifying loop and a harmonic voltage source. The double-side voltage doubling rectifying loop is connected with the wave voltage source; a protective resistor is arranged between the high-voltage input end of the electrical equipment to be tested and the double-side voltage doubling rectifying loop; and the high-voltage input end of the electrical equipment to be tested is connected with the broadband resistance-capacitance voltage divider. The device is suitable for an insulation test of equipment for a direct current system of + / -800kV and below, can carry out a long-term live-line test of direct current superposition harmonic voltage on electrical equipment, and solves the problem that the insulation performance and long-term reliability of the equipment cannot be evaluated.

Description

TECHNICAL FIELD

[0001] The utility model relates to electrical equipment test technical field, concretely relates to a test device of direct current superimposed harmonic voltage. BACKGROUND

[0002] The direct current transmission system plays an extremely important role in the modern power system due to its advantage of efficient transmission of electric energy. However, the stable operation of the system and the reliability of the equipment are faced with the problem of harmonic voltage caused by the nonlinear characteristics of the converter. These harmonic voltages not only cause the accelerated aging of the equipment insulation, reduce the insulation level, but also increase the dielectric loss and may cause abnormal temperature rise, thereby affecting the normal work of the power equipment and the stable operation of the power system.

[0003] In view of this problem, the current national standard and IEC standard mainly consider the three types of voltage of power frequency, direct current and impulse or their partial combination when conducting insulation test, and have not covered the actual operation condition of direct current superimposed harmonic voltage. Such test method is obviously insufficient to comprehensively evaluate the insulation performance and long-term reliability of the equipment under the real operation environment. Especially in the flexible direct current system, such as the key equipment of converter transformer valve side bushing, under the joint action of direct current and high order harmonic voltage, its insulation performance and aging process may be significantly different from the case under the action of pure power frequency or direct current voltage.

[0004] Considering that in actual engineering operation, the valve side bushing and other equipment have appeared faults due to long-term bearing of direct current superimposed harmonic voltage, obviously the existing test method and condition need to be improved and supplemented. In order to ensure the long-term reliability of the equipment and the stable operation of the power system, it is particularly important to research and develop the test voltage source and its test method under the condition of direct current superimposed harmonic voltage in the actual operation.

[0005] Although the Chinese Academy of Electrical Engineering and the domestic high-voltage laboratory with leading technology have mastered the mature test method of applying direct current superimposed power frequency voltage to the valve side bushing and other equipment, this method can only simulate the case of direct current superimposed 50Hz sinusoidal voltage, and cannot cover the high order harmonic voltage from 50Hz fundamental wave to 2500Hz that may appear in actual operation. Therefore, the current method still has limitations and cannot comprehensively evaluate the performance of the equipment under the real operation condition. UTILITY MODEL CONTENTS

[0006] To address the problem that existing technologies lack effective equipment for simulating DC superimposed high-order harmonic voltage conditions, which limits the comprehensive evaluation of equipment insulation performance and long-term reliability, this invention provides a test device for DC superimposed harmonic voltage. It is suitable for insulation testing of equipment used in ±800kV and below DC systems, and can conduct long-term live tests of electrical equipment with DC superimposed harmonic voltage, thus solving the problem that the insulation performance and long-term reliability of equipment cannot be evaluated.

[0007] To achieve the above objectives, the present invention provides the following technical solution.

[0008] This invention provides a test device for DC superimposed harmonic voltage, including a voltage generator for DC superimposed harmonic voltage and an electrical device to be tested. and a wideband RC voltage divider; the voltage generating device for DC superimposed harmonic voltage includes a double-sided voltage multiplier rectifier circuit. and harmonic voltage source The bilateral voltage multiplier rectifier circuit With the wave voltage source Connection; the electrical equipment under test The high-voltage input terminal and the double-sided voltage multiplier rectifier circuit A protective resistor is installed between them. The electrical equipment under test The high-voltage input terminal is connected to the wideband resistor-capacitor voltage divider; the harmonic voltage source The system includes a pre-charge circuit, an AC / DC converter, a DC / AC inverter, an LC filter, a step-up transformer, and an AC / AC converter. The input of the pre-charge circuit is connected to an AC power supply. The output of the pre-charge circuit is connected to the input of the AC / DC converter. The output of the AC / DC converter is connected to the input of the DC / AC inverter. The output of the DC / AC inverter is connected to the input of the LC filter. The output of the LC filter is connected to the input of the step-up transformer. The output of the step-up transformer is connected to the input of the AC / AC converter. The output of the AC / AC converter is connected to a double-sided voltage multiplier rectifier circuit. .

[0009] Optionally, the output of the AC / AC converter is also connected to ground N.

[0010] Optionally, the pre-charge circuit includes a switch. ,switch and resistance The switch The switch is positioned between the AC power source and the AC / DC converter; one end and the resistor one end of the switch the other end of the switch the other end of the switch the other end of the switch the other end of the switch

[0011] optionally, the harmonic voltage source is further connected with an isolation transformer .

[0012] optionally, the double-sided voltage doubler rectifier circuit is provided with a conversion switch K between the harmonic voltage source .

[0013] optionally, the double-sided voltage doubler rectifier circuit is further connected with a charging transformer; the charging transformer is further connected with a voltage input end .

[0014] optionally, the wide frequency band resistance-capacitance voltage divider comprises a high-voltage arm and a low-voltage arm; the high-voltage arm and the low-voltage arm are connected in series; the high-voltage arm is connected with a high-voltage input end of the electrical equipment to be tested; the low-voltage arm is grounded; the high-voltage arm comprises a resistance and a capacitance ; the resistance and the capacitance are connected in parallel; the low-voltage arm comprises a resistance and a capacitance ; the resistance and the capacitance are connected in parallel.

[0015] optionally, the alternating current power supply is 380V; the electrical equipment to be tested is further connected with a measurement system.

[0016] optionally, the double-sided voltage doubler rectifier circuit comprises a plurality of single-stage double-sided voltage doubler rectifier circuits; the plurality of single-stage double-sided voltage doubler rectifier circuits are connected in series.

[0017] ​​Optionally, the single-stage double-sided voltage doubler rectifier circuit comprises high-voltage silicon stacks, charging capacitors and charging resistors; one end of a first charging resistor is connected in series with a first charging capacitor to form a first series module, a second charging resistor is connected in series with a second charging capacitor to form a second series module, a third charging resistor is connected in series with a third charging capacitor to form a third series module, and a fourth charging resistor is connected in series with a fourth charging capacitor to form a fourth series module; the first series module, the second series module, the third series module and the fourth series module are connected in parallel; a second high-voltage silicon stack is arranged between the first charging capacitor and the second charging capacitor, and a fourth high-voltage silicon stack is arranged between the third charging capacitor and the fourth charging capacitor; one end of a first high-voltage silicon stack is arranged between the first charging capacitor and the second high-voltage silicon stack, the other end of the first high-voltage silicon stack is connected to one end of the second charging resistor, one end of a third high-voltage silicon stack is arranged between the fourth high-voltage silicon stack and the fourth charging capacitor, and the other end of the third high-voltage silicon stack is connected to one end of the third charging resistor; the first charging resistor, the second charging resistor, the third charging resistor and the fourth charging resistor are connected in series with a first charging capacitor, a second charging capacitor, a third charging capacitor and a fourth charging capacitor in a next-stage double-sided voltage doubler rectifier circuit, respectively.

[0018] Compared with the prior art, the utility model has the advantages of the following beneficial effects:

[0019] The application can effectively simulate the condition of direct current superimposed high-order harmonic voltage, and through the design of combining the double-sided voltage doubler rectifier circuit with the harmonic voltage source, various voltage conditions that the electrical equipment may encounter in actual operation process are comprehensively simulated, thereby providing strong support for evaluating the insulation performance and long-term reliability of the equipment. Secondly, the harmonic voltage generating device provided by the utility model has high flexibility and adaptability. The device can be applied to the direct current voltage generator of the voltage doubler rectifier circuit of different voltage grades, and is designed in an external mode, so that the whole device can be conveniently installed and removed. This design does not affect the original function of the direct current voltage generator, ensures the safety of the equipment and personnel, and is particularly suitable for environments such as high-voltage test halls and outdoor high-voltage test fields. In addition, the utility model fully considers the discharge fault condition of the test sample to ground during the test, and the whole equipment has a certain insulation level to ground, thereby further improving the safety and reliability of the test process. This is helpful for protecting the expensive electrical equipment and avoiding accidents.

[0020] Further, the harmonic voltage source internally integrates key components such as a pre-charge circuit, an AC / DC converter, a DC / AC inverter, an LC filter, a step-up transformer and an AC / AC converter. Through precise circuit design and control strategy, the stable output and accurate regulation of the harmonic voltage are ensured, and the strict requirements for parameters such as voltage waveform, frequency and amplitude in the insulation test of the electrical equipment are met. BRIEF DESCRIPTION OF DRAWINGS

[0021] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. In the drawings:

[0022] Figure 1 It is a DC superimposed harmonic voltage generator structure diagram of the test device of the DC superimposed harmonic voltage of the utility model;

[0023] Figure 2 It is a harmonic voltage source topology structure diagram of the test device of the DC superimposed harmonic voltage of the utility model;

[0024] Figure 3 It is a DC superimposed harmonic withstand voltage test loop diagram of the test device of the DC superimposed harmonic voltage of the utility model.

[0025] In the figure, 1 is a pre-charge circuit; 2 is an AC / DC converter; 3 is a DC / AC inverter; 4 is an LC filter; 5 is a step-up transformer; 6 is an AC / AC converter. DETAILED DESCRIPTION

[0026] In order to make the person in the art better understand the technical scheme in the utility model, the technical scheme in the utility model will be described clearly and completely below in combination with the drawings in the utility model, and the described embodiments are only a part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of protection of the utility model.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the utility model belongs. The terms used in the specification of the utility model herein are only for the purpose of describing specific embodiments and are not intended to limit the utility model. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0028] In view of the problem that the prior art lacks an effective device for simulating a DC superimposed high-order harmonic voltage condition, which limits comprehensive evaluation of the insulation performance and long-term reliability of electrical equipment, the utility model provides a test device for a DC superimposed harmonic voltage.

[0029] The device comprises a voltage generating device for a DC superimposed harmonic voltage, an electrical equipment to be tested and a wideband resistance-capacitance voltage divider.

[0030] The voltage generating device for a DC superimposed harmonic voltage comprises a double-sided voltage doubling rectifier circuit and a harmonic voltage source A bilateral voltage doubler rectifier circuit connected to the wave voltage source .

[0031] The electrical equipment to be tested connected to the bilateral voltage doubler rectifier circuit A protection resistor is arranged between the bilateral voltage doubler rectifier circuit The electrical equipment to be tested is also connected to a wideband resistance-capacitance voltage divider.

[0032] As shown in Figure 1 , the voltage generating device of the direct current superimposed harmonic voltage further comprises a conversion switch K.

[0033] The bilateral voltage doubler rectifier circuit is connected to the wave voltage source through the conversion switch K.

[0034] The bilateral voltage doubler rectifier circuit is a multi-stage bilateral voltage doubler rectifier circuit. The multi-stage bilateral voltage doubler rectifier circuit is composed of N-stage bilateral voltage doubler rectifier circuits, and the structure and working principle of the single-stage bilateral voltage doubler rectifier circuit are similar.

[0035] The single-stage bilateral voltage doubler rectifier circuit comprises a high-voltage silicon stack, a charging capacitor, and a charging resistor, wherein the number of the high-voltage silicon stack, the charging capacitor, and the charging resistor is 4.

[0036] One end of the first charging resistor is connected in series with the first charging capacitor to form a first series module, the second charging resistor is connected in series with the second charging capacitor to form a second series module, the third charging resistor is connected in series with the third charging capacitor to form a third series module, and the fourth charging resistor is connected in series with the fourth charging capacitor to form a fourth series module. Moreover, the first series module, the second series module, the third series module, and the fourth series module are connected in parallel.

[0037] The second high-voltage silicon stack is arranged between the first charging capacitor and the second charging capacitor, and the fourth high-voltage silicon stack is arranged between the third charging capacitor and the fourth charging capacitor. One end of the first high-voltage silicon stack is arranged between the first charging capacitor and the second high-voltage silicon stack, the other end of the first high-voltage silicon stack is connected to one end of the second charging resistor, one end of the third high-voltage silicon stack is arranged between the fourth high-voltage silicon stack and the fourth charging capacitor, and the other end of the third high-voltage silicon stack is connected to one end of the third charging resistor.

[0038] The first charging resistor, the second charging resistor, the third charging resistor, and the fourth charging resistor are connected in series with the first charging capacitor, the second charging capacitor, the third charging capacitor, and the fourth charging capacitor in the next-stage bilateral voltage doubler rectifier circuit, respectively.

[0039] The plurality of single-stage bilateral voltage doubler rectifier circuits The structure and working principle of the high-voltage silicon stack are similar, so this specification takes the high-voltage silicon stack as an example to describe the specific structure in detail. Figure 1

[0040] charging resistor one end of the charging capacitor one end of the charging capacitor the other end of the charging resistor one end of the charging resistor the other end of the charging capacitor one end of the charging resistor one end of the charging capacitor one end of the charging capacitor

[0041] charging resistor one end of the charging capacitor one end of the charging capacitor the other end of the charging resistor one end of the charging resistor the other end of the charging capacitor one end of the charging resistor one end of the charging capacitor one end of the charging capacitor

[0042] charging resistor one end of the charging capacitor one end of the charging capacitor the other end of the charging resistor one end of the charging resistor the other end of the charging capacitor one end of the charging resistor one end of the charging capacitor one end of the charging capacitor

[0043] charging resistor one end of the charging capacitor one end of the charging capacitor the other end of the charging resistor one end of the charging resistor the other end of the charging capacitor one end of the charging resistor one end of the charging capacitor one end of the charging capacitor

[0044] high-voltage silicon stack one end of the charging capacitor one end of the charging capacitor the other end of the charging resistor one end of the charging resistor the other end of the charging capacitor one end of the charging capacitor​ One end is set in the charging capacitor With charging resistor Between, high-voltage silicon stack The other end is set in the charging resistor With charging capacitor Between, high-voltage silicon stack One end is set in the charging capacitor With charging resistor Between, high-voltage silicon stack The other end is set in the charging resistor With charging capacitor And so on, high-voltage silicon stacks One end is set in the charging capacitor Connection, high-voltage silicon stack The other end is set in the charging resistor With charging capacitor between.

[0045] High-voltage silicon stack One end is set in the charging capacitor With charging resistor Between, high-voltage silicon stack The other end is set in the charging resistor With charging transformer Between; high-voltage silicon stack One end is set in the charging capacitor With charging resistor Between, high-voltage silicon stack The other end is set in the charging resistor With charging capacitor Between, high-voltage silicon stack One end is set in the charging capacitor With charging resistor Between, high-voltage silicon stack The other end is set in the charging resistor With charging capacitor And so on, high-voltage silicon stacks One end is set in the charging capacitor Connection, high-voltage silicon stack The other end is set in the charging resistor With charging capacitor between.

[0046] High-voltage silicon stack One end is set in the charging capacitor With charging resistor Between, high-voltage silicon stack The other end is set in the charging capacitor With charging resistor Between, high-voltage silicon stack One end is set in the charging capacitor With charging resistor Between, high-voltage silicon stack The other end is set in the charging capacitor With charging resistor In between, and so on, high-voltage silicon stacks One end is set in the charging capacitor With charging resistor Between, high-voltage silicon stack The other end is set in the charging capacitor With charging resistor Between, high-voltage silicon stack Set in the charging capacitor With charging resistor between.

[0047] High-voltage silicon stack One end is set in the charging capacitor With charging resistor Between, high-voltage silicon stack The other end is set in the charging capacitor With charging resistor Between, high-voltage silicon stack One end is set in the charging capacitor With charging resistor Between, high-voltage silicon stack The other end is set in the charging capacitor With charging resistor In between, and so on, high-voltage silicon stacks One end is set in the charging capacitor With charging resistor Between, high-voltage silicon stack The other end is set in the charging capacitor With charging resistor Between, high-voltage silicon stack Set in the charging capacitor With charging resistor between.

[0048] Charging resistor With charging resistor Connected between, charging capacitor With charging resistor and charging capacitors With charging resistor Connected between, charging capacitor With charging resistor and charging capacitors With charging resistor The connections between them, and so on, are for charging capacitors. with the charging resistor and the charging capacitor with the charging resistor between the charging resistor with the charging resistor between.

[0049] charging transformer with the charging transformer is also connected to the voltage input , the voltage output is provided on the charging resistor with the charging resistor between.

[0050] charging transformer with the charging resistor is also connected to the harmonic voltage source , the harmonic voltage source is provided with a changeover switch K between the double-sided voltage doubler rectifier circuit, the harmonic voltage source is also connected to the isolation transformer .

[0051] The application starts with the voltage input , which is converted into a voltage suitable for the subsequent charging process by the charging transformer and the charging transformer . Then, a multi-stage charging takes place by the charging resistor and the charging capacitor in the double-sided voltage doubler rectifier circuit. Each charging stage consists of a charging resistor and a charging capacitor, which are connected alternately to form a series circuit.

[0052] The high-voltage silicon stack is used as a rectifying element and is placed in a specific position to ensure that the current can only flow in one direction, thus achieving the conversion of alternating current to direct current.

[0053] The harmonic voltage source is supplied by the isolation transformer and is connected to the double-sided voltage doubler rectifier circuit via the changeover switch K. This means that the harmonic voltage source can be introduced into the double-sided voltage doubler rectifier circuit as required for specific harmonic compensation or regulation of the output voltage. The harmonic voltage source is insulated from ground potential by an insulating support, the insulation level being determined by the insulation level of the charging transformer and the charging transformer secondary winding to ground, which should not be lower than the output voltage of the charging transformer and the charging transformer . The harmonic voltage source is supplied by the isolation transformer Power supply, isolation transformer The output voltage is 380V, which ensures that the harmonic voltage generator works at high potential as a whole. The harmonic voltage generator is a single-phase output voltage source, and the harmonic frequency and amplitude can be adjusted. The control system is connected to the harmonic voltage source through an optical fiber,

[0054] As shown in Figure 2 , the harmonic voltage source includes a pre-charge circuit 1, an AC / DC converter 2, a DC / AC inverter 3, an LC filter 4, a step-up transformer 5, and an AC / AC converter 6.

[0055] The input end of the harmonic voltage source is provided with a pre-charge circuit 1, which can effectively suppress the impact current during startup. The input end of the pre-charge circuit 1 is connected to an AC power supply, and the AC power supply is selected to be 380V; the output end of the pre-charge circuit 1 is connected to the AC / DC converter 2, and the AC / DC converter 2 outputs DC power; the input end of the DC / AC inverter 3 receives DC power from the AC / DC converter 2, and the DC / AC inverter 3 converts the DC power into AC power; the output of the DC / AC inverter 3 is connected to the LC filter 4, which is used to filter high-frequency noise and clutter in the AC power; the output of the LC filter 4 is connected to the step-up transformer 5, which is used to increase the output voltage; the output of the step-up transformer 5 is connected to the AC / AC converter 6, which converts the voltage into the required output voltage; the output of the AC / AC converter 6 is connected to the output end, which is connected to the load L and the ground N, respectively. The load L is connected to the double-sided voltage doubling rectifier circuit . The final AC output is provided. Through multiple converters and filters, conversion from 380V AC to a specific output voltage is achieved, and interference and noise are reduced through the filter.

[0056] The pre-charge circuit 1 includes a switch and a resistor , the switch and the resistor are connected in series, the switch is arranged between the AC power supply and the AC / DC converter 2, and the switch is connected in parallel with the switch and the resistor .

[0057] The harmonic voltage source The input terminal is equipped with a pre-charge circuit, which can effectively suppress the inrush current during startup. A filter is incorporated into the circuit to reduce interference to the output. The power modules in AC / DC converter 2, DC / AC inverter 3, and AC / AC converter 6 utilize IGBTs, and the control module employs a DSP, enabling precise control of the output harmonic order and amplitude. The power supply features monitoring and fault indication / location functions; fault codes can accurately pinpoint the location of any malfunction. Fiber optic communication is used between the device control module and the power modules.

[0058] like Figure 3 As shown, when using this application to conduct insulation tests on electrical equipment for DC systems, the electrical equipment to be tested... With bilateral voltage multiplier rectifier circuit A protective resistor is installed between them. Protective resistor It serves a protective function, preventing excessive current from damaging the electrical equipment under test during a short circuit fault. Bilateral voltage multiplier rectifier circuit Used to provide DC voltage. Double-sided voltage multiplier rectifier circuit. With harmonic voltage source Source connected, harmonic voltage source Used to provide harmonic voltage to electrical equipment under test. It is also connected to a wideband RC divider, which is used to measure the test voltage. The measurement signal is transmitted to the measurement system via cable or optical fiber.

[0059] A broadband resistive-capacitive voltage divider includes a high-voltage arm and a low-voltage arm, with the high-voltage arm connected to the electrical equipment under test. Connection, high voltage arm includes resistor and capacitors ,resistance and capacitors Parallel connection, the low-voltage arm includes a resistor and capacitors ,resistance and capacitors Parallel connection. Electrical equipment to be tested. The monitoring and control signals are connected to the measurement system in the experimental control room via optical fiber.

[0060] Bilateral voltage multiplier rectifier circuit Harmonic voltage source It can output DC or DC voltage with harmonics, and features a double-sided voltage multiplier rectifier circuit. The amplitude of the output DC voltage is adjustable, and it is a harmonic voltage source. It can output combinations of harmonics, and the amplitude is adjustable to meet experimental needs.

[0061] Electrical equipment to be tested Bilateral voltage multiplier rectifier circuit High-voltage wires can be used for the connection between the wideband RC voltage divider and the voltage divider.

[0062] When using the device of this application, when the changeover switch K is in the open position, the DC superimposed harmonic voltage generating device is equivalent to a DC voltage generator, outputting a high DC voltage, and a double-sided voltage multiplier rectifier circuit. It consists of N-stage double-sided voltage multiplier rectifier circuits, with each stage having a maximum output voltage of [value missing]. Then the voltage output terminal The maximum output DC voltage is .

[0063] When the changeover switch K is in the closed position, the harmonic voltage passes through the charging transformer. The secondary winding is coupled to a DC voltage generator. After setting the required harmonic order and amplitude, the output voltage is... This will superimpose harmonic voltage on the DC voltage to simulate the actual working voltage of electrical equipment in a high-voltage DC system, thereby enabling various insulation tests to be conducted.

[0064] In summary, the DC superimposed harmonic voltage test device proposed in this application solves the problem of applying DC superimposed harmonic voltage during electrical equipment testing. It can effectively simulate the conditions of DC superimposed high-order harmonic voltage, realize a comprehensive evaluation of the insulation performance and long-term reliability of the electrical equipment under test, and is applicable to the insulation test of electrical equipment for ultra-high-voltage DC systems.

[0065] The harmonic voltage source in the DC superimposed harmonic voltage voltage generator of this application This DC voltage generator, applicable to voltage multiplier rectifier circuits at various voltage levels, features an outdoor design, allowing for easy installation and removal. Installation does not damage the existing structure of the DC voltage generator, and removal does not affect its original function. It is suitable for high-voltage test halls and outdoor high-voltage test sites. Considering the possibility of ground discharge faults during testing, the entire system has a certain level of insulation to ground, ensuring the safety of equipment and personnel. This invention uses a harmonic voltage source connected in series on the secondary winding side of a charging transformer to couple the harmonic voltage to the high-voltage output terminal. Furthermore, considering the possibility of high-voltage-to-ground faults during testing, the harmonic voltage source is insulated from ground using an insulated support. The support height and insulation level are determined based on the DC voltage generator used. An isolation transformer is used to supply power to the harmonic power supply, ensuring the power supply's insulation level to ground and maintaining the harmonic power supply at a high potential, effectively protecting the internal components from damage due to grounding faults.

[0066] The utility model is further explained and illustrated below in combination with specific embodiments.

[0067] Embodiments

[0068] Electrical equipment to be tested In the voltage generating device superimposed with the DC harmonic voltage, and checking the electrical equipment to be tested And the equipment state of the voltage generating device superimposed with the DC harmonic voltage;

[0069] If the equipment state does not meet the test condition, adjusting the electrical equipment to be tested And the voltage generating device superimposed with the DC harmonic voltage, until the equipment state of the electrical equipment to be tested And the voltage generating device superimposed with the DC harmonic voltage meets the test condition;

[0070] If the equipment state meets the test condition, starting the double-sided voltage doubling rectifier circuit And the harmonic voltage source In the voltage generating device, improving the voltage to the required test voltage through the control system, and confirming the test voltage through the signal of the wideband resistance-capacitance voltage divider;

[0071] Controlling the harmonic voltage source To apply the harmonic voltage, setting the amplitude of each harmonic voltage component as required, and simultaneously observing and starting to record the DC superimposed harmonic voltage measured by the wideband resistance-capacitance voltage divider until the voltage waveform meets the voltage application requirement;

[0072] After the voltage waveform meets the voltage application requirement, outputting the voltage, at which time the electrical equipment to be tested Starts to withstand the voltage, until the specified withstand time is reached, and then gradually reducing the double-sided voltage doubling rectifier circuit And the harmonic voltage source To zero and disconnecting the power supply, and completing the test.

[0073] If the electrical equipment to be tested Fails to withstand the discharge to the ground during the test, the protection system configured in the double-sided voltage doubling rectifier circuit And the harmonic voltage source Will quickly cut off the power supply and ground, ensuring the safety of the electrical equipment to be tested And the operating personnel.

[0074] When the device is used to carry out insulation test on electrical equipment for DC system, the long-term live test of the DC superimposed harmonic voltage applied to the electrical equipment for flexible DC system with voltage grade of ±800kV and below can meet the demand of the DC superimposed arbitrary waveform harmonic voltage applied to the electrical equipment to meet the actual working condition.

[0075] Many embodiments and many applications other than those described herein will be apparent to those skilled in the art from consideration of the specification and practice of the teachings herein. Thus, the scope of the present teachings should not be limited to the specific embodiments described herein, but should be given the broadest interpretation of the appended claims and the full scope of equivalents thereof. All articles and references including patent applications and publications are herein incorporated by reference for the articles or documents as specifically referenced. Any aspect of the subject matter disclosed herein that is not recited in the claims is hereby abandoned.

[0076] The above is further detailed description of the present application, can not be determined that the specific embodiments of the present application is limited to this, for the ordinary skilled in the art to which the present application belongs, without departing from the concept of the present application, can also make a number of simple deduction or replacement, all should be regarded as belonging to the present application by the claims submitted to determine the scope of protection.

Claims

1. A test apparatus for superimposing a harmonic voltage on a direct current, characterized by Voltage generating device including direct current superimposed harmonic voltage, electrical equipment to be tested And wide band resistance-capacitance voltage divider The voltage generating device of the direct current superimposed harmonic voltage comprises a double-sided voltage doubling rectification circuit and a harmonic voltage source ; The double-sided voltage doubling rectifier circuit With the wave voltage source Connection; The electrical equipment to be tested A high-voltage input end of the electrical equipment to be tested is connected to the double-side voltage doubling rectifier circuit A protection resistor is arranged between the high-voltage input end of the electrical equipment to be tested and the double-side voltage doubling rectifier circuit ; The electrical equipment to be tested a high voltage input of the electrical equipment to be tested is connected to the wideband resistive-capacitive voltage divider The harmonic voltage source comprises a pre-charge circuit (1), an AC / DC converter (2), a DC / AC inverter (3), an LC filter (4), a step-up transformer (5) and an AC / AC converter (6); The input end of the pre-charging circuit (1) is connected with an AC power supply, the output end of the pre-charging circuit (1) is connected with the input end of an AC / DC converter (2), the output end of the AC / DC converter (2) is connected with the input end of a DC / AC inverter (3), the output end of the DC / AC inverter (3) is connected with the input end of an LC filter (4), the output end of the LC filter (4) is connected with the input end of a step-up transformer (5), the output end of the step-up transformer (5) is connected with the input end of an AC / AC converter (6); the output end of the AC / AC converter (6) is connected with a double-side voltage doubling rectification circuit .

2. A test apparatus for superimposed harmonic voltages according to claim 1, characterized in that The output end of the AC / AC converter (6) is also connected to the ground N.

3. The test apparatus of claim 1, wherein the test apparatus is configured to apply a DC voltage superimposed with a harmonic voltage to the device under test. The pre-charge circuit (1) comprises a switch , a switch and a resistor ; The switch is arranged between the alternating current source and the AC / DC converter (2); said switch one end of said resistor one end in series The switch The other end is connected between the AC power supply and the switch ​ the resistance the other end of which is connected to the switch between the AC / DC converter (2).

4. The test apparatus of claim 1, wherein The harmonic voltage source Also connected to the isolation transformer Connection.

5. The test apparatus of claim 1, wherein The double-sided voltage doubling rectifier circuit A conversion switch K is provided between the wave voltage source A conversion switch K is provided between the wave voltage source 6. The test apparatus of claim 1, wherein, The double-sided voltage doubling rectifier circuit Also connected to the charging transformer; The charging transformer is also connected with a voltage input Connection.

7. The test apparatus of claim 1, wherein the test apparatus is configured to apply a DC voltage superimposed with a harmonic voltage to the device under test. The wideband resistance-capacitance voltage divider comprises a high-voltage arm and a low-voltage arm; The high-voltage arm and the low-voltage arm are connected in series; The high voltage arm is connected to a high voltage input of the electrical equipment to be tested The low voltage arm is grounded. The high voltage arm comprises a resistor and a capacitor ; the resistance in parallel with the capacitance in parallel; The low voltage arm includes a resistor and a capacitor ; The resistance And the capacitance Are connected in parallel.

8. The test apparatus for superimposed harmonic voltage of direct current according to claim 1, characterized by, The alternating current power supply is 380V. The electrical equipment to be tested Also connected to the measurement system.

9. The test apparatus of claim 1, wherein, The double-sided voltage doubling rectifier circuit comprises several single-stage double-sided voltage doubling rectifier circuits; A plurality of single-stage double-sided voltage doubling rectifier circuits are connected in series.

10. A test apparatus for superimposed harmonic voltages according to claim 9, characterized in that The single-stage double-sided voltage doubling rectifier circuit comprises a high-voltage silicon stack, a charging capacitor and a charging resistor. A first charging resistor and a first charging capacitor are connected in series to form a first series module, a second charging resistor and a second charging capacitor are connected in series to form a second series module, a third charging resistor and a third charging capacitor are connected in series to form a third series module, and a fourth charging resistor and a fourth charging capacitor are connected in series to form a fourth series module; the first series module, the second series module, the third series module and the fourth series module are connected in parallel; A second high-voltage silicon stack is arranged between the first charging capacitor and the second charging capacitor, and a fourth high-voltage silicon stack is arranged between the third charging capacitor and the fourth charging capacitor; one end of a first high-voltage silicon stack is arranged between the first charging capacitor and the second high-voltage silicon stack, the other end of the first high-voltage silicon stack is connected to one end of the second charging resistor, one end of a third high-voltage silicon stack is arranged between the fourth high-voltage silicon stack and the fourth charging capacitor, and the other end of the third high-voltage silicon stack is connected to one end of the third charging resistor; The first charging resistor, the second charging resistor, the third charging resistor and the fourth charging resistor are connected in series with a first charging capacitor, a second charging capacitor, a third charging capacitor and a fourth charging capacitor of a next-stage double-sided voltage doubling rectifier circuit in sequence.

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