A discharge mechanism for short-circuit discharge test of high-voltage and large-capacity DC support capacitors

Abstract

The present invention discloses a discharge mechanism for short-circuit discharge test of high-voltage and large-capacity DC support capacitors. The discharge mechanism is mainly composed of a first connection busbar, a second connection busbar, a copper braided wire, a hinge, a third connection busbar, a first fixed plate, a spring, a cylinder assembly, a support member and a second fixed plate. The second connection busbar, the copper braided wire and the hinge are connected and fixed by nuts, the hinge, the copper braided wire and the third connection busbar are connected and fixed by nuts, the copper braided wire is close to the outer surface of the hinge, the third connection busbar and the first fixed plate are connected and fixed by nuts, the two ends of the spring are respectively connected to the first fixed plate and the second fixed plate, the piston rod of the cylinder is connected to the support member by a latch, and the bottom of the support member is connected to the second fixed plate. The present invention has a simple structure and can meet the requirements of large current impact discharge test of DC support capacitors in terms of operation.

Description

Technical Field

[0001] The invention belongs to the technical field of capacitor testing, and in particular relates to a discharge mechanism for a short-circuit discharge test of a high-voltage and large-capacity DC support capacitor. Background Art

[0002] DC support capacitors are key components of converters, and they play a role in stabilizing voltage and filtering on the DC side of converters. At present, high-power converters such as high-voltage converters of tens of megawatts, high-speed train converters, high-power STATCOMs, and DC capacitors for flexible DC transmission projects all require high-voltage and large-capacity DC support capacitors.

[0003] The common characteristics of this type of capacitor are high voltage and large capacity. The maximum voltage is 6kV DC, the maximum capacity is 10mF, and the maximum surge current, one of the main technical indicators of this type of capacitor, reaches 900kA. The type test of DC support capacitors requires an impulse discharge test, and the capacitor sample should be discharged 5 times. Therefore, there are certain requirements for the test discharge device and circuit.

[0004] Document CN106646173A provides a discharge test circuit and method for a multi-parameter power capacitor, in which a discharge gap is used for discharge. This test circuit is mainly suitable for power capacitors, which have small capacitor capacity and small discharge current. The maximum discharge current of the discharge gap is 200kA, and the conductivity of graphene is poor, which affects the discharge waveform.

[0005] Document CN207067273U provides a metallized component DC short-circuit charge and discharge automatic test device, whose working principle is to control the discharge positive electrode and the secondary electrode to contact and discharge through an electromagnetic mechanism. This device is mainly used for component short-circuit discharge test, and the maximum discharge current is 50kA.

[0006] Document CN203405540U provides a high-voltage DC support capacitor short-circuit discharge test device, whose working principle is to control the upper spherical copper column and the lower graphene electrode to contact and discharge through a cylinder. In this device, the maximum discharge current of the discharge gap is 200kA, and the conductivity of graphene is poor, which affects the discharge waveform.

[0007] At present, when vacuum circuit breakers, thyristors, etc. are used as discharge switches in conventional test devices, the maximum discharge current is 100kA.

[0008] In summary, this type of discharge switch or mechanism is a technical problem that needs to be solved, and is also a key technology that needs to be solved to improve the performance indicators of DC support capacitors. Summary of the invention

[0009] In order to overcome the shortcoming that it is difficult to achieve large current in the short-circuit discharge test of the existing high-voltage and large-capacity DC support capacitor, the present invention proposes a discharge mechanism for the short-circuit discharge test of a high-voltage and large-capacity DC support capacitor (hereinafter referred to as "capacitor").

[0010] The technical solution adopted by the present invention is as follows.

[0011] The invention provides a discharge mechanism for a short-circuit discharge test of a high-voltage and large-capacity DC support capacitor. The capacitor consists of a shell, a first mounting bracket, a second mounting bracket, a positive electrode terminal and a negative electrode terminal.

[0012] The discharge mechanism is mainly composed of a first connecting busbar, a second connecting busbar, a copper braided wire, a hinge, a third connecting busbar, a first fixed plate, a spring, a cylinder assembly, a support and a second fixed plate. The cylinder assembly includes a cylinder body, a first air inlet, a second air inlet, a piston rod, an action hose, a reset hose, a cylinder action switch, an air source and a cylinder fixed plate. The second connecting busbar, the copper braided wire and the hinge are connected and fixed by nuts. The hinge, the copper braided wire and the third connecting busbar are connected and fixed by nuts. The copper braided wire is close to the outer surface of the hinge. The third connecting busbar and the first fixed plate are connected and fixed by nuts. The two ends of the spring are respectively connected to the first fixed plate and the second fixed plate. The piston rod of the cylinder is connected to the support. The bottom of the support is connected to the second fixed plate.

[0013] The first connecting busbar is connected to the negative electrode terminal, and the second connecting busbar is connected to the positive electrode terminal.

[0014] Cylinder fixing plate and first mounting bracket connected and fixed

[0015] The second fixing plate is connected and fixed to the second mounting bracket.

[0016] The first connecting busbar is composed of a first connecting busbar body and a first mounting hole, has a rectangular shape, is made of copper, has a thickness of 12-15 mm, and is a through hole.

[0017] The second connecting busbar is composed of a second connecting busbar body, a second mounting hole and a first fixing hole. It is rectangular in shape, made of copper, and has a thickness of 12-15 mm. The second mounting hole is a through hole, and the first fixing hole has a depth of 10-12 mm.

[0018] The third connecting busbar is composed of the third connecting busbar body, the second fixing hole, the third fixing hole and the semi-cylindrical surface. It is an integrated structure, its material is copper, its thickness is 12~15mm, the second fixing hole is on the front side, the third fixing hole is on the back side, and the depth of the hole is 10~12mm.

[0019] Copper braided wire cross-sectional area 240mm 2 , its width is 60mm.

[0020] The spring diameter is 35mm, its wire diameter is 3mm, its length is 400mm, and the free length is 750mm.

[0021] The first fixing plate is an insulating plate, which is rectangular in shape and made of insulating materials such as epoxy resin.

[0022] The second fixing plate is rectangular in shape and is made of stainless steel.

[0023] The support component consists of a main body, a top hemisphere, a middle hole and a bottom hole. The support component is made of insulating materials such as epoxy resin and wood, and has a shape of a cube or a cylinder.

[0024] The cylinder fixing plate is made of stainless steel.

[0025] Furthermore, the top of the piston rod of the cylinder is in the middle hole of the support member and is connected together by a latch.

[0026] Furthermore, the circular rings at both ends of the spring can facilitate connection with the first fixing plate and the second fixing plate, and the contact position of the connection can be adjusted during operation.

[0027] Furthermore, the first connecting busbar may also be connected to the positive electrode terminal, and in this case, the second connecting busbar is connected to the negative electrode terminal.

[0028] Furthermore, the piston rod of the cylinder can be a single rod or a double rod, and the cylinder action switch can be controlled manually or by a solenoid valve.

[0029] Furthermore, the cylinder fixing plate and the second fixing plate can be installed on a special fixing bracket.

[0030] The beneficial effects of the present invention are as follows: the discharge circuit is a copper bus and copper braided wire, the circuit has small inductance and resistance, and the test discharge current reaches more than 900kA; the test operation is simple, easy to maintain, highly reliable and safe.

[0031] The invention has a simple structure and is easy to operate, and can meet the requirements of large current impact discharge test of DC support capacitors. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of a test circuit for implementing the present invention;

[0033] Figure 2 A schematic diagram of the present invention being implemented on a capacitor;

[0034] Figure 3 for Figure 2 Application diagram;

[0035] Figure 4 for Figure 2 A magnified view of part A;

[0036] Figure 5 is a schematic diagram of the main components of the present invention;

[0037] In the figure, 1-DC test power supply; 2-charging switch; 3-voltage measurement; 4-high voltage and large capacity DC support capacitor; 5-current measurement; 6-discharging mechanism;

[0038] 41-housing; 42-first mounting bracket; 43-second mounting bracket; 44-positive electrode terminal; 45-negative electrode terminal;

[0039] 60-first connecting busbar; 61-second connecting busbar; 62-copper braided wire; 63-hinge; 64-third connecting busbar;

[0040] 65-first fixing plate; 66-spring; 67-cylinder assembly; 68-support member; 69-second fixing plate;

[0041] 601-first connecting busbar body; 602-first mounting hole;

[0042] 611-second connecting busbar body; 612-second mounting hole; 613-first fixing hole;

[0043] 641-third connecting busbar body; 642-second fixing hole; 643-third fixing hole; 644-semi-cylindrical surface;

[0044] 671- cylinder body; 672- first air inlet; 673- second air inlet; 674- piston rod; 675- action hose; 676- reset hose; 677- cylinder action switch; 678- air source; 679- cylinder fixing plate;

[0045] 681-main body; 682-top hemisphere; 683-middle hole; 684-bottom hole. DETAILED DESCRIPTION

[0046] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0047] exist Figure 1 As can be seen, the test circuit implemented in the present invention is composed of a DC test power supply (1), a charging switch (2), a voltage measurement (3), a high-voltage and large-capacity DC support capacitor (4), a current measurement (5) and a discharge mechanism (6).

[0048] from Figures 2~5 visible:

[0049] The high-voltage and large-capacity DC support capacitor (4) is composed of a housing (41), a first mounting bracket (42), a second mounting bracket (43), a positive electrode terminal (44) and a negative electrode terminal (45);

[0050] The discharge mechanism (6) is mainly composed of a first connecting busbar (60), a second connecting busbar (61), a copper braided wire (62), a hinge (63), a third connecting busbar (64), a first fixing plate (65), a spring (66), a cylinder assembly (67), a support member (68) and a second fixing plate (69); the cylinder assembly (67) includes a cylinder body (671), a first air inlet (672), a second air inlet (673), a piston rod (674), an action hose (675), a reset hose (676), a cylinder action switch (677), an air source (678) and a cylinder fixing plate (679); The second connecting busbar (61), the copper braided wire (62) and the hinge (63) are connected by nuts; the hinge (63), the copper braided wire (62) and the third connecting busbar (64) are connected and fixed by nuts; the copper braided wire (62) is close to the outer surface of the hinge (63); the third connecting busbar (64) and the first fixing plate (65) are connected and fixed by nuts; the two ends of the spring (66) are respectively connected to the first fixing plate (65) and the second fixing plate (69); the piston rod (674) of the cylinder (67) is connected to the support member by a latch; the bottom of the support member (68) is connected to the second fixing plate (69);

[0051] The first connecting busbar (60) is connected to the negative electrode terminal (45), and the second connecting busbar (61) is connected to the positive electrode terminal (64); the cylinder fixing plate (679) is connected and fixed to the first mounting bracket (42); and the second fixing plate (69) is connected and fixed to the second mounting bracket (43);

[0052] The first connecting busbar (60) is composed of a first connecting busbar body (601) and a first mounting hole (602), and the first mounting hole is a through hole; the second connecting busbar (61) is composed of a second connecting busbar body (611), a second mounting hole (612) and a first fixing hole (613), and its shape is rectangular, and the second mounting hole is a through hole; the third connecting busbar (64) is composed of a third connecting busbar body (641), a second fixing hole (642), a third fixing hole (643) and a semi-cylindrical surface (644), and it is an integrated structure, the second fixing hole (642) is on the front side, and the third fixing hole (643) is on the back side; the supporting member (68) is composed of a body (681), a top hemispherical body (682), a middle hole (683) and a bottom hole (684);

[0053] Before the test, the spring (66) is manually extended to the maximum stroke, and the cylinder action switch (677) is operated to make the piston rod (674) of the cylinder (67) pull the support member (68), so that the top hemispherical body (682) just contacts the first fixing plate (65);

[0054] During the test, when the voltage measurement (3) reads the rated value, the charging switch (2) is disconnected, and the cylinder action switch (677) is operated to make the piston rod (674) of the cylinder (67) push the support member (68) forward, and the top hemisphere (682) contacts and separates from the first fixed plate (65). At this time, the tension of the spring (66) makes the semi-cylindrical surface (644) of the third connecting busbar (64) contact with the first connecting busbar (64), and short-circuit discharge occurs. At this time, the spring (66) is still in a stretched state, and no electric force rebound occurs.

[0055] Furthermore, the top of the piston rod (674) of the cylinder (67) is in the middle hole (683) of the support member (68) and is connected together by a latch.

[0056] Furthermore, the circular rings at both ends of the spring (67) can facilitate connection with the first fixing plate (65) and the second fixing plate (69), and the contact position of the connection can be adjusted during operation.

[0057] Furthermore, the first connecting busbar (60) may also be connected to the positive electrode terminal (44), and in this case, the second connecting busbar (61) is connected to the negative electrode terminal (65).

[0058] Furthermore, the piston rod (674) of the air cylinder (67) can be a single rod or a double rod, and the air cylinder action switch (677) can be controlled manually or by a solenoid valve.

[0059] Furthermore, the cylinder fixing plate (679) and the second fixing plate (69) can be mounted on a dedicated fixing bracket.

[0060] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A discharge mechanism for short-circuit discharge test of high-voltage and large-capacity DC support capacitors, characterized by: The high-voltage and large-capacity DC support capacitor is composed of a shell, a first mounting bracket, a second mounting bracket, a positive terminal and a negative terminal; the discharge mechanism includes a first connecting busbar, a second connecting busbar, a copper braided wire, a hinge, a third connecting busbar, a first fixing plate, a spring, a cylinder assembly, a support and a second fixing plate, the cylinder assembly includes a cylinder body, a first air inlet, a second air inlet, a piston rod, an action hose, a reset hose, a cylinder action switch, an air source and a cylinder fixing plate, the first connecting busbar is connected to the negative / positive terminal, the second connecting busbar is connected to the other terminal; the cylinder fixing plate is connected and fixed to the first mounting bracket; the second fixing plate is connected and fixed to the second mounting bracket; The second connecting busbar, the copper braided wire and the hinge are connected and fixed by nuts, the hinge, the copper braided wire and the third connecting busbar are connected and fixed by nuts, the copper braided wire is close to the outer surface of the hinge, the third connecting busbar and the first fixing plate are connected and fixed by nuts, the two ends of the spring are connected to the first fixing plate and the second fixing plate respectively, the piston rod of the cylinder is connected to the support member by a latch, and the bottom of the support member is connected to the second fixing plate; A first air inlet is provided at the first end of the cylinder body, and a second air inlet is provided at the second end. The first air inlet is connected to the cylinder action switch through a reset hose, and the second air inlet is connected to the cylinder action switch through an action hose. An air source is provided on the cylinder action switch, a piston rod is provided on the side of the first air inlet, and a cylinder fixing plate is provided on the cylinder body; The support member is composed of a main body, a top hemisphere, a middle hole and a bottom hole; the top of the piston rod of the cylinder is in the middle hole of the support member and is connected together by a pin; before the test, the spring is manually extended to the maximum stroke, and the cylinder action switch is operated to make the piston rod of the cylinder pull the support member, and the top hemisphere is just in contact with the first fixed plate; during the test, when the voltage measurement reading reaches the rated value, the charging switch is disconnected, and the cylinder action switch is operated to make the piston rod of the cylinder push the support member forward, and the top hemisphere is in contact with the first fixed plate and separated, at which time the spring tension makes the semi-cylindrical surface of the third connecting busbar contact with the first connecting busbar, resulting in short-circuit discharge.

2. The discharge mechanism according to claim 1, characterized in that: The first connecting busbar is composed of a first connecting busbar body and a first mounting hole, and the first connecting busbar and the positive / negative terminal of the high-voltage and large-capacity DC support capacitor are connected through the first mounting hole; the first connecting busbar is rectangular in shape, the first connecting busbar material is copper, the first connecting busbar thickness is 12~15mm, and the first mounting hole is a through hole.

3. The discharge mechanism according to claim 1, characterized in that: The second connecting busbar is composed of a second connecting busbar body, a second mounting hole and a first fixing hole. The second connecting busbar is rectangular in shape, the second connecting busbar is made of copper, the second connecting busbar is 12 to 15 mm thick, the second mounting hole is a through hole, and the first fixing hole is 10 to 12 mm deep; the first fixing hole is connected and fixed to the copper braided wire and the hinge by a nut; the first mounting hole is connected to the negative / positive terminal.

4. The discharge mechanism according to claim 1, characterized in that: The third connecting busbar is composed of a third connecting busbar body, a second fixing hole, a third fixing hole and a semi-cylindrical surface. The third connecting busbar is an integrated structure. The material of the third connecting busbar is copper. The thickness of the third connecting busbar is 12~15mm. The second fixing hole is on the front side, the third fixing hole is on the back side, and the depth of the hole is 10~12mm. The third connecting busbar body is connected and fixed to the hinge and the copper braided wire by nuts, and the third fixing hole is connected and fixed to the first fixing plate by nuts. The raised part of the semi-cylindrical surface can contact the first connecting busbar.

5. The discharge mechanism according to claim 1, characterized in that: The support member is made of epoxy resin or wood insulating material and is in the shape of a cube or a cylinder.

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