Testing device for direct-current superposition harmonic voltage and use method

Abstract

The invention discloses a direct current superposition harmonic voltage testing device and a use method, and belongs to the technical field of electrical equipment testing. The device comprises a voltage generating device of direct current superposition harmonic voltage, to-be-tested electrical equipment # imgabs0 # 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 circuit # imgabs 1 # and a harmonic voltage source # imgabs 2 #. The double-side voltage doubling rectifying loop # imgabs3 # is connected with the wave voltage source # imgabs4 #; a protective resistor # imgabs7 # is arranged between the high-voltage input end of the electrical equipment # imgabs5 # to be tested and the double-side voltage doubling rectifying circuit # imgabs6 #; and the high-voltage input end of the electrical equipment # imgabs8 # 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 present invention relates to the technical field of electrical equipment testing, and in particular to a testing device for direct current superimposed harmonic voltage and a use method thereof. Background Art

[0002] The DC 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 will not only cause the insulation of the equipment to age faster and reduce the insulation level, but also increase the dielectric loss and may cause abnormal temperature rise, thus affecting the normal operation of the power equipment and the stable operation of the power system.

[0003] In response to this problem, the current national and IEC standards mainly consider three types of voltages, namely power frequency, DC, and impulse, or some combination thereof, when conducting insulation tests, and have not yet covered the actual operating conditions of DC superimposed harmonic voltages. Such a test method is obviously not enough to fully evaluate the insulation performance and long-term reliability of the equipment under the actual operating environment. Especially in flexible DC systems, key equipment such as the valve-side bushings of converter transformers, under the combined effects of DC and high-order harmonic voltages, may have significantly different insulation performance and aging processes from those under the effects of pure power frequency or DC voltage.

[0004] Considering that in actual engineering operation, equipment such as valve-side bushings have already experienced failures due to long-term exposure to DC superimposed harmonic voltages, it is obvious that existing test methods and conditions need to be improved and supplemented. In order to ensure the long-term reliability of equipment and the stable operation of the power system, it is particularly important to research and develop test voltage sources and test methods that can simulate the DC superimposed harmonic voltage conditions in actual operation.

[0005] Although the domestic high-voltage laboratories with leading technology have mastered the mature test method of applying DC superimposed power frequency voltage to valve-side bushings and other equipment, this method can only simulate the situation of DC superimposed 50Hz sinusoidal voltage, and cannot cover the high-order harmonic voltages from 50Hz fundamental wave to 2500Hz that may appear in actual operation. Therefore, the current method still has limitations and cannot fully evaluate the performance of the equipment under real operating conditions. Summary of the invention

[0006] In view of the problem in the prior art that there is a lack of equipment that can effectively simulate the conditions of DC superimposed high-order harmonic voltage, which limits the comprehensive evaluation of the insulation performance and long-term reliability of the equipment, the present invention provides a test device for DC superimposed harmonic voltage, which is suitable for insulation testing of equipment used in DC systems of ±800kV and below, and can carry out long-term live testing of DC superimposed harmonic voltage on electrical equipment, thus solving the problem that the insulation performance and long-term reliability of the equipment cannot be evaluated.

[0007] In order to achieve the above object, the present invention provides the following technical solutions.

[0008] In a first aspect, the present invention provides a test device for a DC superimposed harmonic voltage, comprising a voltage generating device for a DC superimposed harmonic voltage, an electrical device to be tested, and a wide-band resistor-capacitor voltage divider; the voltage generating device for the DC superimposed harmonic voltage includes a double-sided voltage doubler rectifier circuit and harmonic voltage sources The double-sided voltage doubler rectifier circuit With the wave voltage source Connection; the electrical equipment to be tested The high voltage input terminal and the double-sided voltage doubler rectifier circuit A protective resistor is provided between ; The electrical equipment to be tested The high voltage input end is connected to the wide-band RC voltage divider; the harmonic voltage source The invention comprises a pre-charging circuit, an AC / DC converter, a DC / AC inverter, an LC filter, a boost transformer and an AC / AC converter; the input end of the pre-charging circuit is connected to an AC power source, the output end of the pre-charging circuit is connected to the input end of the AC / DC converter, the output end of the AC / DC converter is connected to the input end of the DC / AC inverter, the output end of the DC / AC inverter is connected to the input end of the LC filter, the output end of the LC filter is connected to the input end of the boost transformer, the output end of the boost transformer is connected to the input end of the AC / AC converter; the output end of the AC / AC converter is connected to a double-sided voltage doubler rectifier circuit .

[0009] As a further improvement of the present invention, the output end of the AC / AC converter is further connected to a ground line N.

[0010] As a further improvement of the present invention, the pre-charging circuit includes a switch ,switch and resistor The switch The switch is arranged between the AC power supply and the AC / DC converter; one end and the resistor One end is connected in series; the switch The other end is connected to the AC power supply and the switch between; the resistance The other end is connected to the switch and between the AC / DC converter.

[0011] As a further improvement of the present invention, the harmonic voltage source Also with isolation transformer connect.

[0012] As a further improvement of the present invention, the double-sided voltage doubler rectifier circuit With the wave voltage source A changeover switch K is provided between them.

[0013] As a further improvement of the present invention, the double-sided voltage doubler rectifier circuit The charging transformer is also connected to the voltage input terminal connect.

[0014] As a further improvement of the present invention, the broadband RC voltage divider comprises a high voltage arm and a low voltage arm; the high voltage arm is connected in series with the low voltage arm; the high voltage arm is connected in series with the electrical equipment to be tested. The high voltage arm is connected to the high voltage input terminal; the low voltage arm is grounded; the high voltage arm includes a resistor and capacitor The resistor With the capacitor In parallel; the low voltage arm includes a resistor and capacitor The resistor And the capacitor in parallel.

[0015] As a further improvement of the present invention, the AC power supply is selected to be 380V; the electrical equipment to be tested Also connected to the measurement system.

[0016] In a second aspect, the present invention provides a method for using a test device for a DC superimposed harmonic voltage, comprising: The electrical equipment to be tested Connect to the voltage generator of DC superimposed harmonic voltage and check the electrical equipment to be tested and the equipment status of the voltage generating device of the DC superimposed harmonic voltage; If the equipment status meets the test conditions, the double-sided voltage doubler rectifier circuit in the voltage generator is started. Harmonic voltage sources ; Controlling harmonic voltage sources Apply harmonic voltage until the voltage waveform meets the pressure requirements. At this time, the electrical equipment to be tested Start to withstand the voltage until the specified tolerance time is reached, and then gradually reduce the double-sided voltage doubler rectifier circuit Harmonic voltage sources To zero and disconnect the power supply, the test is completed.

[0017] As a further improvement of the present invention, the control harmonic voltage source Apply harmonic voltage until the voltage waveform meets the pressure requirements. At this time, the electrical equipment to be tested Start to tolerate this voltage, after which: If the electrical equipment to be tested Tolerance failure discharge to ground, double-sided voltage doubler rectifier circuit Harmonic voltage sources It will be cut off and grounded immediately, and the test is over.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present application can effectively simulate the conditions of direct current superimposed high-order harmonic voltages. By adopting a design combining a bilateral voltage doubler rectifier circuit with a harmonic voltage source, the present invention can fully simulate various voltage conditions that may be encountered by electrical equipment during actual operation, thereby providing strong support for evaluating the insulation performance and long-term reliability of the equipment. Secondly, the harmonic voltage generating device proposed in the present invention has a high degree of flexibility and adaptability. The device can not only be applied to DC voltage generators with voltage doubler rectifier circuits of different voltage levels, but also adopts an outdoor design, so that the entire device can be easily installed and removed. This design does not affect the original function of the DC voltage generator, but also ensures the safety of equipment and personnel. It is particularly suitable for environments such as high-voltage test halls and outdoor high-voltage test sites. In addition, the present invention also fully considers the discharge failure of the test sample to the ground during the test. The entire set of equipment has a certain insulation level to the ground, which further improves the safety and reliability of the test process. This is very important for protecting expensive electrical equipment and avoiding accidents.

[0019] Furthermore, the harmonic voltage source integrates key components such as pre-charging circuit, AC / DC converter, DC / AC inverter, LC filter, step-up transformer and AC / AC converter. Through precise circuit design and control strategy, it ensures the stable output and precise regulation of harmonic voltage, and meets the strict requirements for voltage waveform, frequency, amplitude and other parameters in the insulation test of electrical equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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: Figure 1 A schematic diagram of the structure of a DC superimposed harmonic voltage generator of a DC superimposed harmonic voltage test device of the present invention; Figure 2 A schematic diagram of a harmonic voltage source topology structure of a test device for direct current superimposed harmonic voltage according to the present invention; Figure 3 The present invention discloses a DC superimposed harmonic withstand voltage test circuit diagram of a DC superimposed harmonic voltage test device.

[0021] In the figure, 1 is a pre-charging circuit; 2 is an AC / DC converter; 3 is a DC / AC inverter; 4 is an LC filter; 5 is a boost transformer; and 6 is an AC / AC converter. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0024] In view of the problem in the prior art that there is a lack of equipment for effectively simulating DC superimposed high-order harmonic voltage conditions, which limits the comprehensive evaluation of the insulation performance and long-term reliability of electrical equipment, the present invention provides a test device for DC superimposed harmonic voltage.

[0025] The device includes a voltage generator for DC superimposed harmonic voltage, and the electrical equipment to be tested. And wideband RC voltage divider.

[0026] The voltage generating device of DC superimposed harmonic voltage includes a double-sided voltage doubler rectifier circuit and harmonic voltage sources . Double-sided voltage doubler rectifier circuit With wave voltage source connect.

[0027] Electrical equipment to be tested With double-sided voltage doubler rectifier circuit A protective resistor is provided between , electrical equipment to be tested It is also connected to a wideband RC voltage divider.

[0028] like Figure 1 As shown, the voltage generating device of the DC superimposed harmonic voltage also includes a conversion switch K.

[0029] Double-sided voltage doubler rectifier circuit By switching switch K and wave voltage source connect.

[0030] Double-sided voltage doubler rectifier circuit It is a multi-stage double-sided voltage doubler rectifier circuit. The multi-stage double-sided voltage doubler rectifier circuit is composed of N-stage double-sided voltage doubler rectifier circuits, and the structure and working principle of the single-stage double-sided voltage doubler rectifier circuit are similar.

[0031] Single-stage double-side voltage doubler rectifier circuit It includes 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.

[0032] 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. In addition, the first series module, the second series module, the third series module and the fourth series module are connected in parallel.

[0033] 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, and the other end of the first high-voltage silicon stack is arranged and connected to one end of the second charging resistor, and 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.

[0034] 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 in sequence.

[0035] Several single-stage double-side voltage doubler rectifier circuits The structure and working principle are similar, so this manual is based on Figure 1 Take the example to describe its specific structure in detail.

[0036] Charging resistor One end and the charging capacitor One end is connected in series, charging capacitor The other end of the charging resistor One end is connected in series, charging resistor The other end is connected to the charging capacitor One end is connected in series, and so on, the charging resistor One end and the charging capacitor One end is connected in series.

[0037] Charging resistor One end and the charging capacitor One end is connected in series, charging capacitor The other end of the charging resistor One end is connected in series, charging resistor The other end is connected to the charging capacitor One end is connected in series, and so on, the charging resistor One end and the charging capacitor One end is connected in series.

[0038] Charging resistor One end and the charging capacitor One end is connected in series, charging capacitor The other end of the charging resistor One end is connected in series, charging resistor The other end is connected to the charging capacitor One end is connected in series, and so on, the charging resistor One end and the charging capacitor One end is connected in series.

[0039] Charging resistor One end and the charging capacitor One end is connected in series, charging capacitor The other end of the charging resistor One end is connected in series, charging resistor The other end is connected to the charging capacitor One end is connected in series, and so on, the charging resistor One end and the charging capacitor One end is connected in series.

[0040] High Voltage Silicon Stack One end is set to charge the capacitor With charging resistor Between, high voltage silicon stack The other end is set to the charging resistor With charging transformer Between; High Voltage Silicon Stack One end is set to charge the capacitor With charging resistor Between, high voltage silicon stack The other end is set to the charging resistor With charging capacitor Between, high voltage silicon stack One end is set to charge the capacitor With charging resistor Between, high voltage silicon stack The other end is set to the charging resistor With charging capacitor Between, and so on, high voltage silicon stack One end is set to charge the capacitor Connection, high voltage silicon stack The other end is set to the charging resistor With charging capacitor between.

[0041] High Voltage Silicon Stack One end is set to charge the capacitor With charging resistor Between, high voltage silicon stack The other end is set to the charging resistor With charging transformer Between; High Voltage Silicon Stack One end is set to charge the capacitor With charging resistor Between, high voltage silicon stack The other end is set to the charging resistor With charging capacitor Between, high voltage silicon stack One end is set to charge the capacitor With charging resistor Between, high voltage silicon stack The other end is set to the charging resistor With charging capacitor Between, and so on, high voltage silicon stack One end is set to charge the capacitor Connection, high voltage silicon stack The other end is set to the charging resistor With charging capacitor between.

[0042] High Voltage Silicon Stack One end is set to charge the capacitor With charging resistor Between, high voltage silicon stack The other end is set to charge the capacitor With charging resistor Between, high voltage silicon stack One end is set to charge the capacitor With charging resistor Between, high voltage silicon stack The other end is set to charge the capacitor With charging resistor Between, and so on, high voltage silicon stack One end is set to charge the capacitor With charging resistor Between, high voltage silicon stack The other end is set to charge the capacitor With charging resistor Between, high voltage silicon stack Set the charging capacitor With charging resistor between.

[0043] High Voltage Silicon Stack One end is set to charge the capacitor With charging resistor Between, high voltage silicon stack The other end is set to charge the capacitor With charging resistor Between, high voltage silicon stack One end is set to charge the capacitor With charging resistor Between, high voltage silicon stack The other end is set to charge the capacitor With charging resistor Between, and so on, high voltage silicon stack One end is set to charge the capacitor With charging resistor Between, high voltage silicon stack The other end is set to charge the capacitor With charging resistor Between, high voltage silicon stack Set the charging capacitor With charging resistor between.

[0044] Charging resistor With charging resistor Connected, charging capacitor With charging resistor And charging capacitor With charging resistor Connected, charging capacitor With charging resistor And charging capacitor With charging resistor The charging capacitors are connected. With charging resistor And charging capacitor With charging resistor Connected between, charging resistor With charging resistor Connected between.

[0045] Charging transformer With charging transformer Also with the voltage input Connection, voltage output Set the charging resistor With charging resistor between.

[0046] Charging transformer With charging resistor Between the harmonic voltage source Connection, harmonic voltage source A conversion switch K is provided between the double-sided voltage doubler rectifier circuit and the harmonic voltage source Also with isolation transformer connect.

[0047] This application is from the voltage input terminal Start by charging the transformer And charging transformer , converting the input AC voltage into a voltage suitable for the subsequent charging process. Then, multi-stage charging is performed through the charging resistor and charging capacitor in the double-sided voltage doubler rectifier circuit. Each charging stage consists of a charging resistor and a charging capacitor, which are alternately connected to form a series circuit.

[0048] High-voltage silicon stacks are used as rectifying elements and are placed in specific positions to ensure that current can only flow in one direction, thereby achieving conversion from AC to DC.

[0049] Harmonic voltage source Through the isolation transformer Power supply, and connected to the double-sided voltage doubler rectifier circuit through the conversion switch K. This shows that the harmonic voltage source It can be introduced into the double-sided voltage doubler rectifier circuit when needed to compensate for specific harmonics or adjust the output voltage. Insulated from ground potential by insulating support, the insulation level is determined by the charging transformer And charging transformer The insulation level of the secondary winding to the ground is determined by the insulation level of the secondary winding to the ground, which should not be lower than that of the charging transformer. And charging transformer Output voltage. Harmonic voltage source By isolation transformer Power supply, isolation transformer The output voltage is 380V, which ensures that the harmonic voltage generator works at a high potential as a whole. The harmonic voltage generator is a single-phase output voltage source, and the output harmonic order and amplitude are adjustable. The control system is connected to the harmonic voltage source through optical fiber. like Figure 2 As shown, the harmonic voltage source The system includes a pre-charging 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 .

[0050] Harmonic voltage source The input end is provided with a pre-charging circuit 1, which can effectively suppress the impact current at startup. The input end of the pre-charging 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-charging circuit 1 is connected to an AC / DC converter 2, and the output of the AC / DC converter 2 is DC power. The input end of the DC / AC inverter 3 receives the 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 an LC filter 4, and the LC filter 4 is used to filter out high-frequency noise and clutter in the AC power; the output of the LC filter 4 is connected to a step-up transformer 5, and the step-up transformer 5 is used to increase the output voltage. The output of the step-up transformer 5 is connected to an AC / AC converter 6 to convert the voltage into the required output voltage; the output of the AC / AC converter 6 is connected to the load L and the ground wire N respectively, and the load L is connected to the double-sided voltage doubler rectifier circuit. Connection. Provide the final AC output. Through multiple converters and filters, the conversion from 380V AC to a specific output voltage is achieved, and the interference and noise are reduced through the filter.

[0051] The pre-charge circuit 1 includes a switch and resistor ,switch and resistor Series, switch Set between the AC power supply and the AC / DC converter 2, the switch With switch and resistor in parallel.

[0052] Harmonic voltage source The input end of the power supply is equipped with a pre-charging circuit, which can effectively suppress the impact current during startup. A filter is configured in the circuit to reduce interference with the output. The power modules in the AC / DC converter 2, DC / AC inverter 3, and AC / AC converter 6 use IGBT, and the control module uses DSP, which can accurately control the number and amplitude of output harmonics. The power supply has monitoring and fault prompt / location functions, and when a fault occurs, it can be accurately located through the fault code. Optical fiber communication is used between the equipment control module and the power module.

[0053] 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 double-sided voltage doubler rectifier circuit A protective resistor is provided between , protection resistor It plays a protective role to prevent the electrical equipment to be tested from being damaged by excessive current during short circuit failure. , double-sided voltage doubler rectifier circuit Used to provide DC voltage. Double-sided voltage doubler rectifier circuit With harmonic voltage source Source connected, harmonic voltage source Used to provide harmonic voltage to test electrical equipment It is also connected to a wide-band RC voltage divider, which is used to measure the test voltage, and the measurement signal is transmitted to the measurement system through a cable or an optical fiber.

[0054] The wideband RC voltage divider includes a high voltage arm and a low voltage arm. The high voltage arm and the electrical equipment to be tested connection, the high voltage arm includes a resistor and capacitor ,resistance and capacitor Parallel, low voltage arm includes resistor and capacitor ,resistance and capacitor Parallel. Electrical equipment to be tested The monitoring and control signals are connected to the measurement system in the experimental control room via optical fiber.

[0055] Double-sided voltage doubler rectifier circuit With harmonic voltage source Can output DC or DC superimposed harmonic voltage, double-sided voltage doubler rectification circuit The amplitude of the output DC voltage is adjustable, harmonic voltage source The combination of various harmonics can be output, and the amplitude is adjustable to meet the experimental needs.

[0056] Electrical equipment to be tested Double-sided voltage doubler rectifier circuit High voltage wires can be used to connect the wide-band RC voltage divider.

[0057] When the device of the present application is used, when the conversion switch K is in the open position, the voltage generating device of the DC superimposed harmonic voltage is equivalent to a DC voltage generator, outputting a DC high voltage, and a double-sided voltage doubler rectifier circuit. It consists of N-stage double-sided voltage doubler rectifier circuits. The maximum output voltage of each double-sided voltage doubler rectifier circuit is , then the voltage output terminal The maximum output DC voltage is .

[0058] When the transfer switch K is in the closed position, the harmonic voltage passes through the charging transformer The secondary winding is coupled to the DC voltage generator. After setting the required harmonic order and amplitude, the output voltage Harmonic voltage will be superimposed on the DC voltage to simulate the actual working voltage of electrical equipment in the high-voltage DC system, so that various insulation tests can be carried out.

[0059] In summary, the test device for DC superimposed harmonic voltage proposed in this application solves the problem of applying DC superimposed harmonic voltage when testing electrical equipment. It can effectively simulate the equipment under DC superimposed high-order harmonic voltage conditions, realize a comprehensive evaluation of the insulation performance and long-term reliability of the electrical equipment to be tested, and is suitable for insulation testing of electrical equipment for ultra-special DC systems.

[0060] Harmonic voltage source in the voltage generating device of direct current superimposed harmonic voltage of the present application It can be applied to a DC voltage generator with a voltage doubling rectifier circuit of different voltage levels. It adopts an outdoor design. The whole device can be easily installed and removed. The existing structure of the DC voltage generator is not destroyed during installation, and the original function of the DC voltage generator is not affected after removal. It is suitable for high-voltage test halls and outdoor high-voltage test sites. Considering the discharge failure of the test sample to the ground during the test, the whole set of equipment has a certain insulation level to the ground, ensuring the safety of equipment and personnel. The present invention adopts the method of connecting a harmonic voltage source in series on the secondary winding side of the charging transformer to couple the harmonic voltage to the high-voltage output end. In addition, the present application takes into account the situation of the high-voltage end to the ground during the test. The harmonic voltage source is insulated from the ground by an insulating support as a whole. The support height and insulation level are determined according to the DC voltage generator used. An isolation transformer is used to supply power to the harmonic power supply to ensure the insulation level of the power supply to the ground, ensure that the harmonic power supply is at a high potential as a whole, and effectively protect the internal components of the harmonic power supply from being damaged by ground faults.

[0061] The second object of the present invention is to provide a method for using a test device for DC superimposed harmonic voltage, comprising: Electrical equipment to be tested Connect to the voltage generator of DC superimposed harmonic voltage and check the electrical equipment to be tested and the equipment status of the voltage generating device of the DC superimposed harmonic voltage; If the equipment status does not meet the test conditions, the electrical equipment to be tested and the voltage generator of DC superimposed harmonic voltage, and adjust it until the electrical equipment to be tested The equipment status of the voltage generating device of the DC superimposed harmonic voltage meets the test conditions; If the equipment status meets the test conditions, the double-sided voltage doubler rectifier circuit in the voltage generator is started. Harmonic voltage sources , increase the voltage to the required test voltage through the control system, and confirm the test voltage through the signal of the wide-band RC divider; Controlling harmonic voltage sources Apply harmonic voltage, set the amplitude of each harmonic voltage component as required, and observe and start recording the DC superimposed harmonic voltage measured by the wide-band RC divider until the voltage waveform meets the pressure application requirements; After the voltage waveform meets the pressure requirements, the voltage is output. At this time, the electrical equipment to be tested Start to withstand the voltage until the specified tolerance time is reached, and then gradually reduce the double-sided voltage doubler rectifier circuit Harmonic voltage sources To zero and disconnect the power supply, the test is completed.

[0062] If the electrical equipment to be tested Tolerance failure discharge to ground, double-sided voltage doubler rectifier circuit Harmonic voltage sources The configured protection system will quickly cut off the power supply and ground it to ensure that the electrical equipment to be tested and the safety of operators.

[0063] When using the device to carry out insulation tests on electrical equipment used in DC systems, the device can be used for long-term live tests on electrical equipment used in flexible DC systems with voltage levels of ±800kV and below, applying DC superimposed harmonic voltages of arbitrary waveforms to electrical equipment to meet the requirements of actual working conditions.

[0064] Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the preceding claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to be a disclaimer of such subject matter, nor should it be considered that the applicants did not consider such subject matter to be part of the disclosed inventive subject matter.

[0065] The above content is a further detailed description of the present invention. It cannot be determined that the specific implementation methods of the present invention are limited to these. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, they can also make several simple deductions or substitutions, which should be regarded as belonging to the protection scope of the present invention determined by the submitted claims.

Claims

1. A test device for DC superimposed harmonic voltage, characterized in that: Including voltage generators with DC superimposed harmonic voltages and electrical equipment to be tested and wideband RC voltage divider; The voltage generating device of the DC superimposed harmonic voltage includes a double-sided voltage doubler rectifier circuit. and harmonic voltage sources ; The double-sided voltage doubler rectifier circuit With the wave voltage source connect; The electrical equipment to be tested The high voltage input terminal and the double-sided voltage doubler rectifier circuit A protective resistor is provided between ; The electrical equipment to be tested The high voltage input terminal is connected to the broadband RC voltage divider; The harmonic voltage source It includes a pre-charging 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 to an AC power source, the output end of the pre-charging circuit (1) is connected to the input end of the AC / DC converter (2), the output end of the AC / DC converter (2) is connected to the input end of the DC / AC inverter (3), the output end of the DC / AC inverter (3) is connected to the input end of the LC filter (4), the output end of the LC filter (4) is connected to the input end of the boost transformer (5), the output end of the boost transformer (5) is connected to the input end of the AC / AC converter (6); the output end of the AC / AC converter (6) is connected to a double-sided voltage doubler rectifier circuit .

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

3. A test device for DC superimposed harmonic voltage according to claim 1, characterized in that: The pre-charging circuit (1) comprises a switch ,switch and resistance ; The switch arranged between the AC power source and the AC / DC converter (2); The switch one end and the resistor One end is connected in series; The switch The other end is connected to the AC power supply and the switch between; The resistance The other end is connected to the switch and between the AC / DC converter (2).

4. A test device for DC superimposed harmonic voltage according to claim 1, characterized in that: The harmonic voltage source Also with isolation transformer connect.

5. A test device for DC superimposed harmonic voltage according to claim 1, characterized in that: The double-sided voltage doubler rectifier circuit With the wave voltage source A changeover switch K is provided between them.

6. A test device for DC superimposed harmonic voltage according to claim 1, characterized in that: The double-sided voltage doubler rectifier circuit It is also connected to the charging transformer; The charging transformer is also connected to the voltage input terminal connect.

7. A test device for DC superimposed harmonic voltage according to claim 1, characterized in that: The broadband RC voltage divider comprises a high voltage arm and a low voltage arm; The high-voltage arm is connected in series with the low-voltage arm; The high voltage arm and the electrical equipment to be tested The high voltage power input terminal is connected; the low voltage arm is grounded; The high voltage arm includes a resistor and capacitor ; The resistance With the capacitor in parallel; The low voltage arm includes a resistor and capacitor ; The resistance And the capacitor in parallel.

8. A test device for DC superimposed harmonic voltage according to claim 1, characterized in that: The AC power supply is 380V; The electrical equipment to be tested Also connected to the measurement system.

9. A method for using a test device for DC superimposed harmonic voltage, characterized in that: A test device for direct current superimposed harmonic voltage according to claim 1 and claim 8, comprising: The electrical equipment to be tested Connect to the voltage generator of DC superimposed harmonic voltage and check the electrical equipment to be tested and the equipment status of the voltage generating device of the DC superimposed harmonic voltage; If the equipment status meets the test conditions, the double-sided voltage doubler rectifier circuit in the voltage generator is started. Harmonic voltage sources ; Controlling harmonic voltage sources Apply harmonic voltage until the voltage waveform meets the pressure requirements. At this time, the electrical equipment to be tested Start to withstand the voltage until the specified tolerance time is reached, and then gradually reduce the double-sided voltage doubler rectifier circuit Harmonic voltage sources To zero and disconnect the power supply, the test is completed.

10. The method for using the test device for DC superimposed harmonic voltage according to claim 9, characterized in that: The controlled harmonic voltage source Apply harmonic voltage until the voltage waveform meets the pressure requirements. At this time, the electrical equipment to be tested Start to tolerate this voltage, after which: If the electrical equipment to be tested Tolerance failure discharge to ground, double-sided voltage doubler rectifier circuit Harmonic voltage sources It will be cut off and grounded immediately, and the test is over.

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