Large-current generation module and turn-off device short-circuit current test device

Abstract

The invention discloses a short-circuit current test device for a large current generation module and a turn-off device, which is particularly suitable for testing high-performance power electronic devices such as an insulated gate bipolar transistor (IGBT), an integrated gate commutated thyristor (IGCT) and the like. The test device integrates a large current generation module based on a direct current support capacitor bank, a reactor, a control device formed by an auxiliary valve bank, a measuring device and other parts, and aims to accurately control the performance of a power electronic product in a short-circuit current test and meet the test requirements of a high-voltage large-power device. The device provides a comprehensive test platform for the function and performance test of the turn-off devices, and provides solid technical support for the application of the devices in a power grid.

Description

Technical Field

[0001] The invention belongs to the technical field of power equipment testing, and in particular relates to a large current generating module and a short-circuit current testing device for a switchable device. Background Art

[0002] In the current renewable energy structure, hydropower, photovoltaic and wind power generation occupy a dominant position, and their grid connection and long-distance large-capacity transmission all rely on the support of flexible DC transmission systems. In weak AC grid scenarios such as island power transmission and offshore wind power, the reliance on flexible DC transmission technology is particularly significant. As the core of flexible DC transmission technology, modular multilevel (MMC) voltage source converter has become the mainstream technical route due to its maturity, wide applicability, high safety and stability. With the deepening of energy reform, in order to support the large-scale access of new energy and the transmission of electricity from clean energy bases, valves for MMC voltage source converters (MMC converter valves) are developing towards larger capacity and higher reliability.

[0003] Technological progress in power devices has provided internal motivation and technical support for the development of MMC converter valves. The technical parameters of turn-off devices such as IGBT and IGCT have been continuously improved, supporting the rapid increase in the capacity of converters for flexible DC transmission. As a key item in the type test of MMC converter valves, the short-circuit current test focuses on evaluating the performance of converter valves under fault conditions, and is an important means of evaluating their working reliability and short-circuit fault resistance. With the increase in the capacity of flexible DC transmission converter valves and the development of hybrid DC transmission technology, the engineering short-circuit capacity has continued to increase, and the requirements for the short-circuit current tolerance of MMC converter valves have become increasingly stringent. The test parameters are close to the tolerance limit of power devices.

[0004] Traditional short-circuit current tests are usually based on direct testing of short-circuit generators using thyristor converter valve fault current tests. This method can only meet the requirements for MMC converter valve tests where the DC component of the short-circuit current does not account for a high proportion. Summary of the invention

[0005] The present invention provides a large current generating module and a short-circuit current testing device for a switchable device, which can meet the testing requirements of different voltage source converter valves, while taking into account the short-circuit current testing requirements of thyristor valve sections and the electrical testing requirements of diode valves.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A large current generating module comprises a plurality of DC support capacitor modules, wherein the DC support capacitor modules are connected in parallel or in series via switches, and the DC support capacitor modules comprise a plurality of stacked layers of capacitors, wherein each layer of capacitors comprises a plurality of capacitors connected in series; a pneumatic switch k1 for connecting to a main incoming line is arranged at the head end of each layer of capacitors, and a pneumatic double-position switch k2 is arranged at the tail end, wherein one end of the pneumatic double-position switch k2 is used to connect to a main outgoing line, and the other end position is used to connect to the head end incoming line of the next layer of capacitors.

[0008] Furthermore, capacitors at different layers are isolated by insulating pillars.

[0009] Furthermore, a single-station pneumatic switch K3 is provided at the input and output terminals of each layer of capacitors.

[0010] Furthermore, the inlet and outlet terminals of the DC support capacitor module are provided with a DC power supply for charging the DC support capacitor module.

[0011] Furthermore, the inlet and outlet terminals of the DC support capacitor module are provided with discharge resistors with pneumatic switches k4.

[0012] Furthermore, the capacitors are connected by wide copper busbars.

[0013] Furthermore, a pressure release device is provided on the capacitor unit.

[0014] A short-circuit current test device for a switchable device, comprising the above-mentioned current generating module, a reactor and a measurement and control device;

[0015] Each group is connected to a reactor and a thyristor auxiliary valve;

[0016] The measurement and control device is used to select appropriate test equipment parameters from a variety of short-circuit current test modes corresponding to the target short-circuit current test system according to the required test objectives, and provide short-circuit current for the device under test by controlling the target pneumatic switch, capacitor, thyristor auxiliary valve trigger sequence and corresponding multiple thyristor auxiliary valves of the corresponding short-circuit current test.

[0017] Furthermore, a voltage transformer is provided between the DC support capacitor module and the reactor.

[0018] Further, the measurement and control device includes a control and protection device, and the control and protection device includes a main control chassis, a valve control chassis, a time synchronization device, a switch and a human-machine interface;

[0019] The main control box collects the switch quantity and state quantity of the pneumatic switch, current transformer and voltage transformer, and transmits them to the human-machine interface through the switch;

[0020] The valve control box is connected to the converter valve and is used to control the opening and closing state of the converter valve;

[0021] The switch and time synchronization device are both connected with human-machine interface and two-way communication.

[0022] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0023] The present invention is a method based on using a DC support capacitor as a controllable short-circuit current source. The test equipment provided can meet the test requirements of different voltage source converter valves, while taking into account the short-circuit current test of the thyristor valve section and the electrical test requirements of the diode valve. It also has the following advantages:

[0024] 1) The test device includes a reactor and a modular DC support capacitor group with adjustable capacitance value. The head end of the DC support capacitor is provided with a pneumatic switch k1 for connecting to the main incoming line, and the tail end is provided with a pneumatic double-position switch k2. One end of the pneumatic double-position switch k2 is used to connect to the main outgoing line, and the other end position is used to connect to the head end incoming line of the next layer of DC support capacitors. By controlling the on and off of these pneumatic switches, the series or parallel connection of multi-layer capacitors can be easily realized, and the capacitor capacity can be adjusted.

[0025] This test device can more accurately simulate and test the performance of power electronic devices under extreme conditions, providing important guarantees for the safe and reliable operation of power systems.

[0026] Furthermore, a single-position pneumatic switch K3 is provided at the inlet and outlet terminals of each layer of DC support capacitors. The single-position pneumatic switch K3 can short-circuit the entire layer of capacitors and shut them down when necessary without affecting the use of other capacitors.

[0027] Furthermore, the line end and the outlet end of the capacitor group are provided with a discharge resistor with a pneumatic switch, which is used to quickly release the charge inside the capacitor after the test is completed or in an emergency, thereby ensuring the safety of personnel and equipment, protecting electronic components, ensuring the normal operation of the circuit, and facilitating the retesting or use of the capacitor.

[0028] Furthermore, a pressure release device is provided on the capacitor, which can release the internal pressure and send a signal to the outside after gas is generated due to an internal outgoing electrical fault, thereby avoiding explosion of the capacitor and protecting the safety of personnel and equipment.

[0029] Furthermore, wide copper busbars are used to connect capacitors. Due to their excellent conductivity, wide copper busbars can significantly reduce the resistance and voltage drop between capacitors, ensuring efficient and stable power transmission. At the same time, wide copper busbars can still maintain good shape and connectivity under high temperature and high pressure environments, improving the reliability and stability of the system and reducing failures caused by connection problems.

[0030] The short-circuit current test device for a switchable device provided by the present invention comprises three groups of capacitor modules, each group of capacitor modules is matched with a reactor and a converter valve at the front end, two of the groups of capacitor modules provide a current with a DC component for the current loop through the on-off of the converter valve during the discharge process, and the other group of capacitor modules provides an AC component current. The test device has the following advantages:

[0031] 1) Flexible, decoupled, and independently adjustable AC and DC components;

[0032] 2) The DC short-circuit current component with a decay constant that meets the requirements;

[0033] 3) AC and DC components can be precisely superimposed and controlled.

[0034] The present invention not only has a high degree of integration, a compact structure and a small footprint, but is also intelligent and flexible, and can remotely adjust various equipment parameters, thereby improving the digitization and convenience of the test device, and further improving the accuracy, reliability and controllability of the test, and can provide important data support for the design and optimization of power electronic devices, thereby promoting the development and application of power electronic technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of the main wiring circuit of the short-circuit current test device provided by the present invention;

[0036] Figure 2 This is the front view of the modular DC support capacitor bank;

[0037] Figure 3 This is the left view of the modular DC support capacitor bank;

[0038] Figure 4 This is the main wiring diagram of the capacitor module;

[0039] Figure 5 It is a DC support capacitor with a pressure relief valve and a pressure switch;

[0040] Figure 6 It is a combination of a discharge resistor and a pneumatic switch;

[0041] Figure 7 It is a schematic diagram of the primary circuit connection relationship between the control protection equipment and the short-circuit current test system.

[0042] In the attached figure: 1. pressure relief valve; 2. pressure switch; 3. valve plate type discharge resistor. DETAILED DESCRIPTION

[0043] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0045] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be another element centered thereon. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be another element centered thereon at the same time. The terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc. used herein indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. 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 related listed items.

[0047] The present invention provides a large current generating module and a short-circuit current testing device for a switchable device. The large current generating module, the reactor, the control device composed of an auxiliary valve group, the measuring device and other components of the DC support capacitor group provide a compact, high-capacity, automated short-circuit current testing platform for power electronic devices, especially insulated gate bipolar transistors (IGBTs) and integrated gate-commutated thyristors (IGCTs). The platform aims to accurately control the performance of power electronic products in short-circuit current tests, meet the test requirements of high-voltage and high-power devices, and provide solid technical support for the application of these devices in power grids.

[0048] High current: refers to current greater than 50kA.

[0049] Example 1

[0050] This embodiment provides a large current generation module, including three DC support capacitor modules, each DC support capacitor module includes several layers of stacked capacitors, and each layer of capacitors includes several capacitors connected in series using wide copper busbars. Different layers of capacitors are isolated by insulating pillars to meet the interlayer withstand voltage requirements.

[0051] The head end of the capacitor is provided with a pneumatic switch k1 for connecting to the main incoming line, and the tail end is provided with a pneumatic double-position switch k2, one end of which is used to connect to the main outgoing line, and the other end is used to connect to the head end incoming line of the next layer of capacitors. A single-position pneumatic switch K3 is provided at the incoming and outgoing line ends of each layer of capacitors.

[0052] The inlet and outlet terminals of the DC support capacitor module are provided with a DC charging power supply for charging the DC support capacitor module. The inlet and outlet terminals of the DC support capacitor module are connected in parallel with a discharge resistor with a pneumatic switch k4.

[0053] Example 2

[0054] The short-circuit current test device based on the DC support capacitor can accurately simulate the performance of power electronic devices under extreme short-circuit conditions. The design of the device takes into account modularity, flexibility, automation and scalability to meet the testing needs of different voltage levels and power levels.

[0055] In this application example, the primary circuit of the target short-circuit current test system is as follows: Figure 1 As shown, in the figure, V1 to V5 all represent thyristor auxiliary valves, Kv1 to Kv2 all represent knife switches, L1 to L4 all represent reactors, PT1 to PT4 all represent voltage sensors, kc1 to kc3 represent charging contactors, Ud1 to Ud3 all represent voltage sources, C1 to C3 represent DC support capacitor modules, k1 to k4 represent pneumatic switches, k5 to k7 represent jumper switches, R1 to R3 all represent discharge resistors, CT1 to CT4 all represent current sensors, KQ1 and KQ2 represent grounding knife switches, and the test product represents the target converter valve. The operation test circuit is used to perform a normal operation test of the converter valve.

[0056] Reference Figure 1 A short-circuit current test device for a DC support capacitor-based device that can be turned off includes a modular DC support capacitor group, a reactor and an automated precision measurement and control device.

[0057] The modular DC support capacitor bank includes a plurality of DC support capacitor modules, one end of each DC support capacitor module is directly grounded or grounded through a grounding switch, and the other end is connected to the first end of the reactor, the other end of the reactor is connected to one end of the thyristor auxiliary valve, the other end of one of the reactors is connected to two reverse-parallel thyristor auxiliary valves, the other end of the thyristor auxiliary valve is connected to the reactor L4, the reactor L4 is connected to one end of the thyristor auxiliary valve V5, and the other end of the thyristor auxiliary valve V5 is used to connect the test turnable device.

[0058] The following is an introduction to each component.

[0059] 1) Modular DC support capacitor bank

[0060] The high current generation module based on the DC support capacitor group is the main part of the invention. It is composed of multiple DC support capacitor modules in parallel or series to achieve the required short-circuit current capacity. Each group of capacitor modules consists of multiple solid-state capacitor units, which are connected in parallel through wide copper busbars to reduce internal impedance and increase current carrying capacity. The series and parallel configurations of the capacitor modules can be flexibly adjusted by pneumatic switches to adapt to different test conditions.

[0061] like Figure 2 and Figure 3 As shown, the modular DC support capacitor bank is roughly divided into three groups C1, C2, and C3 in terms of structure, which are used to meet the test methods of diode valves, thyristor valves, half-bridge valve sections, and full-bridge valve sections. The DC support capacitor is placed on a steel frame and is stacked in several layers. Each layer of the capacitor is composed of 2, 3, 4 or more capacitor units connected in series ( Figure 2 and Figure 3The figure shows a schematic diagram of three capacitor units connected in series). The capacitors are connected in series to raise the allowable charging voltage of the capacitor module. The capacitors are connected by wide copper busbars. A pneumatic switch k1 is set at the head end of the capacitor. The pneumatic switch is a single-position switch used to connect to the main incoming line IN; at the tail end of the capacitor, a pneumatic double-position switch k2 is set, one end is used to connect to the main outgoing line OUT, and the other end can be connected to the head-end incoming line of the next layer; thus, multi-layer capacitors can be used in series or in parallel. There is also a single-position pneumatic switch K3 at the input and output ends of each layer of capacitors, which can be used to short-circuit the entire layer of capacitors and exit operation when necessary, without affecting the use of other capacitors. Pneumatic switches are used for operation. When the insulation performance is met, the operation can be performed through background calculation to realize the automation of capacitor capacity adjustment. DC charging power supplies Ud1, Ud2, and Ud3 are provided between the input and output terminals of the capacitor bank to charge the corresponding capacitor bank. Discharge resistors R1, R2, and R3 with pneumatic switches k4 are provided to quickly discharge the internal charge of the capacitor after the test or in an emergency. A capacitor protection device is provided to monitor the capacitor status. The main wiring diagram of the capacitor module is shown in the attached Figure 4 .

[0062] The capacitor C uses a DC support capacitor as a capacity unit, and its internal structure is solid-state. Its storage energy is more than ten times that of an oil-immersed pulse capacitor of the same volume, and the number of short-circuit discharge shocks it can withstand is equivalent to that of a pulse capacitor, thus greatly reducing the footprint of the module. The DC support capacitor is equipped with a pressure release device, which includes a pressure relief valve 1 and a pressure switch 2. The pressure switch 2 provides a pair of pressure node signals for protection transmission. When gas is generated due to an internal electrical fault in the outgoing line, the internal pressure can be released and a signal can be sent out. The damaged capacitor can be found through the configured capacitor protection device, and this function is not available in traditional oil-immersed pulse capacitors. See attached. Figure 5 .

[0063] The discharge resistors R1, R2 and R3 are valve-type discharge resistors 3, which have the advantages of small size, high energy density and convenient integration compared with traditional metal wire resistors. The supporting insulator at the bottom of the valve-type resistor is shared with the support of the static blade of the pneumatic switch to form a combination with the pneumatic switch k4, thereby greatly reducing the footprint of the discharge resistor and the switch, making the device more compact. For details, see the attached Figure 6 .

[0064] The DC charging power supply Ud1, DC charging power supply Ud2 and DC charging power supply Ud3 adopt high-frequency shift full-bridge soft switching technology, which has ultra-high short-circuit resistance and stability, as well as high precision, high efficiency, low ripple, small size and other excellent characteristics. It can be remotely controlled by connecting to the control system.

[0065] 2) Reactor

[0066] Reactors L1, L2 and L3 play a key role in this device. They help stabilize the short-circuit current, limit the rising rate of the short-circuit current, and accurately control the overcurrent impulse discharge waveform. The design of the reactor takes into account the magnetic saturation effect and iron loss to ensure stability and reliability under high current conditions.

[0067] 3) Automated precision measurement and control device

[0068] The automated precision measurement and control device is a device used to provide a converter valve short-circuit current test method, device and control protection equipment. The device can select appropriate test equipment parameters from a variety of short-circuit current test modes corresponding to the target short-circuit current test system according to the required test objectives, and conduct a short-circuit current test on the target converter valve in the target short-circuit current test system by controlling the target knife switch, target capacitor, target thyristor auxiliary valve trigger sequence and corresponding multiple target thyristor valves of the corresponding short-circuit current test. During the test, sensor data in the target short-circuit current test system is collected, and corresponding test results are generated based on the sensor data, so as to improve the efficiency and automation of the converter valve short-circuit current test, thereby improving the reliability of the test results. Appendix Figure 7 It is a schematic diagram of the primary circuit connection relationship between the control protection equipment and the short-circuit current test system in the application example.

[0069] Different test modes can also be preset. In each mode, the switching timing of each knife switch, pneumatic switch, contactor, thyristor auxiliary valve and grounding knife switch is determined. For example, four test modes are set: thyristor valve test, flexible DC half-bridge valve test, flexible DC full-bridge test and DC circuit breaker test.

[0070] The control and protection equipment includes a main control chassis, a valve control chassis, a time synchronization device, a switch, a power supply and a human-machine interface.

[0071] The main control box collects the switch quantity and state quantity of the pneumatic switch, current transformer and voltage transformer, and transmits them to the switch; the switch quantity refers to the open or closed state of the switch, and the state quantity includes the voltage value measured by the voltage transformer and the current value measured by the current transformer;

[0072] The valve control box and the converter valve are connected via optical fiber, and the valve control box is used to control the on and off states of the thyristor valve.

[0073] The main control chassis and the valve control chassis communicate with the switch in two-way, and the switch transmits the data of the main control chassis and the valve control chassis to the human-machine interface. The switch and the time synchronization device communicate with the human-machine interface in two-way to ensure the consistency of system time. The switch is powered by a power supply.

[0074] The main economic indicators and parameters of the device are as follows:

[0075] The total peak value of the expected short-circuit current is 50kA.

[0076] The maximum DC component is 25kA;

[0077] The maximum AC component is 25kA.

[0078] The term "consisting of" describing a combination shall include the identified elements, ingredients, parts or steps and other elements, ingredients, parts or steps that do not substantially affect the basic novel characteristics of the combination. The use of the terms "comprising" or "including" to describe a combination of elements, ingredients, parts or steps herein also contemplates embodiments that consist essentially of these elements, ingredients, parts or steps. By using the term "may", it is intended to illustrate that any of the attributes described that "may" be included are optional.

[0079] Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure "one" or "an" used to describe an element, ingredient, part or step is not intended to exclude other elements, ingredients, parts or steps.

[0080] It should be understood that the above description is for illustration and not for limitation. 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 foregoing 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 foregoing claims is not intended to be a waiver of such subject matter, nor should it be considered that the applicant has not considered such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A high current generating module, characterized in that: It comprises a plurality of DC support capacitor modules, wherein the DC support capacitor modules are connected in parallel or in series through switches, and the DC support capacitor module comprises a plurality of stacked capacitors, and each capacitor layer comprises a plurality of capacitors connected in series; The head end of each layer of capacitors is provided with a pneumatic switch k1 for connecting to the main incoming line, and the tail end is provided with a pneumatic double-position switch k2. One end of the pneumatic double-position switch k2 is used to connect to the main outgoing line, and the other end position is used to connect to the head end incoming line of the next layer of capacitors.

2. A high current generating module according to claim 1, characterized in that: The capacitors on different layers are isolated by insulating pillars.

3. A high current generating module according to claim 1 or 2, characterized in that: The inlet and outlet terminals of each layer of capacitors are provided with a single-station pneumatic switch K3.

4. A high current generating module according to claim 1, characterized in that: The inlet and outlet terminals of the DC support capacitor module are provided with a DC power supply for charging the DC support capacitor module.

5. A high current generating module according to claim 1, characterized in that: The inlet and outlet terminals of the DC support capacitor module are provided with discharge resistors with pneumatic switches k4.

6. A high current generating module according to claim 1, characterized in that: The capacitors are connected by wide copper busbars.

7. A high current generating module according to claim 1, characterized in that: The capacitor unit is provided with a pressure release device.

8. A short-circuit current test device for a switchable device, characterized in that: It comprises the current generating module, the reactor and the measurement and control device as claimed in claim 1; Each group is connected to a reactor and a thyristor auxiliary valve; The measurement and control device is used to select appropriate test equipment parameters from a variety of short-circuit current test modes corresponding to the target short-circuit current test system according to the required test objectives, and provide short-circuit current for the device under test by controlling the target pneumatic switch, capacitor, thyristor auxiliary valve trigger sequence and corresponding multiple thyristor auxiliary valves of the corresponding short-circuit current test.

9. A short-circuit current test device for a switchable device according to claim 8, characterized in that: A voltage transformer is arranged between the DC support capacitor module and the reactor.

10. A short-circuit current test device for a switchable device according to claim 8, characterized in that: The measurement and control device includes a control and protection device, and the control and protection device includes a main control chassis, a valve control chassis, a time synchronization device, a switch and a human-machine interface; The main control box collects the switch quantity and state quantity of the pneumatic switch, current transformer and voltage transformer, and transmits them to the human-machine interface through the switch; The valve control box is connected to the converter valve and is used to control the opening and closing state of the converter valve; The switch and time synchronization device are both connected with human-machine interface and two-way communication.

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