Capacitor reactive power compensation device for test and use method

Abstract

The invention belongs to the technical field of capacitors, and discloses a test capacitor reactive power compensation device and a use method, the device comprises an insulation platform, the bottom of the insulation platform is connected with an insulation support member, and a plurality of capacitors are placed on the insulation platform in a single layer; the top of the capacitor is provided with sleeves, and the sleeves are connected through a connecting wire. Shells of the capacitors are connected through equipotential lines; and the bottom of the insulating supporting piece is connected with an insulating supporting column base grounding wire. The space height and the maintenance difficulty can be reduced. The single-layer platform type structure greatly reduces the space height and the maintenance difficulty, and is suitable for places with narrow space and limited height.

Description

Technical Field

[0001] The invention belongs to the technical field of capacitors, and in particular relates to a reactive power compensation device for a test capacitor and a use method thereof. Background Art

[0002] When conducting high current tests on transformers and reactors, capacitors need to be connected in parallel to compensate for reactive current in the circuit, reduce reactive power consumption on the power supply side, and reduce the capacity of the test power supply. In order to facilitate external wiring, the multi-layer tower structure has horizontal placement of compensation capacitors, and pneumatic switches are installed on the outside of the tower frame to achieve multi-layer series and parallel connection, which requires sufficient space to meet the insulation air gap.

[0003] At present, the reactive power compensation devices of parallel capacitors used in experiments are all placed in a tower style, consisting of multiple tower layers, which range from a few to more than ten layers. This structure not only requires sufficient space height, but is also difficult to maintain.

[0004] Therefore, when the space height is limited, how to use parallel capacitors for reactive power compensation is a problem to be solved in this technical field.

[0005] The Chinese patent publication number is CN207732441U, and the name is a patent application for a high-voltage parallel capacitor compensation device. The device includes an insulating bracket and a high-voltage reactive automatic compensation box. The high-voltage reactive automatic compensation box is fixedly installed on the upper surface of the insulating bracket. The upper surface of the high-voltage reactive automatic compensation box is provided with a tightening bolt, and the conductive end of the tightening bolt is connected to the circuit breaker through a wire. The circuit breaker is fixedly installed on the connecting rod. The high-voltage reactive automatic compensation box is also provided with a parallel capacitor compensation circuit inside. The circuit adopts a reactive compensation device based on zero-sequence current, so that when protecting the parallel capacitor group, it is only necessary to install a zero-sequence current transformer at the beginning of each parallel capacitor group. By detecting the magnitude of the zero-sequence current, the faulty capacitor group can be judged, and the fault in the capacitor group can be effectively protected quickly, which reduces the protection cost, simplifies the protection setting calculation, and improves the operating reliability of the reactive compensation device. However, this patent application cannot solve the problem of how to reduce the occupied space and reduce the difficulty of maintenance. Summary of the invention

[0006] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a test capacitor reactive compensation device and a method of use. The test capacitor reactive compensation device adopts a single-layer platform structure, so that the test capacitor reactive compensation device can be arranged in a small area.

[0007] To achieve the above object, the technical solution adopted by the present invention is: In a first aspect, the present invention provides a reactive power compensation device for a test capacitor, comprising: an insulating platform, an insulating support member connected to the bottom of the insulating platform, and a plurality of capacitors placed in a single layer on the insulating platform; a sleeve is provided on the top of the capacitor, and the sleeves are connected by wiring; the outer shells of the capacitors are connected by equipotential lines; and the bottom of the insulating support member is connected to a grounding wire of the base of an insulating support column.

[0008] Optionally, the insulating support member is an insulating support column, and the bottom of the insulating support member has a metal base.

[0009] Optionally, the capacitor is placed vertically on the insulating platform, and the length of the insulating support is less than 2m.

[0010] Optionally, the number of the insulating platforms is greater than one, and the multiple insulating platforms are arranged in multiple groups, each group of insulating platforms is arranged linearly, the capacitors in the same group of insulating platforms are a capacitor group, and the capacitors in the same capacitor group are connected in parallel.

[0011] Optionally, the capacitor groups are connected in star connection or delta connection to form a three-phase output, or multiple groups are connected in parallel or in series to form a single-phase output.

[0012] Optionally, the wiring and equipotential lines are both bare copper wires.

[0013] Optionally, the insulating platform is an insulating wooden board.

[0014] Optionally, the capacitor is an oil-filled capacitor.

[0015] Optionally, the capacity of the capacitor is 50 kvar or 100 kvar or 200 kvar or 300 kvar or 500 kvar.

[0016] In a second aspect, the present invention provides a method for using the test capacitor reactive power compensation device, comprising the following steps: During installation, place the capacitor vertically on an insulating platform; The bushings of the capacitors are connected by wiring; and the shells of the capacitors are connected by equipotential lines.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The existing laboratory's compensation parallel capacitor structure is a multi-layer tower, and a lifting vehicle is required for maintenance. The present invention discloses a platform-placed parallel capacitor reactive power compensation device, which can reduce the space height and maintenance difficulty. The single-layer platform structure of the present invention greatly reduces the space height and maintenance difficulty. The single-layer platform structure enables the compensation capacitor to be placed vertically, and the series and parallel connections are directly connected using wires, saving space and cost.

[0018] Furthermore, the present invention is suitable for places with small space and limited height, and can be arranged in a straight line or in a triangle according to the shape of the site, without the need for other switches and control systems. The present invention can be applied to reactive power compensation for transformer and reactor product tests, and can change the connection mode and the number of capacitor groups according to actual compensation needs to meet the requirements of different voltage levels and different compensation capacities. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are for explanation purposes only and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only for illustration purposes to help understand the present invention, and are not intended to specifically limit the shapes and proportional dimensions of the components of the present invention. In the drawings: Figure 1 It is a front schematic diagram of the present invention; Figure 2 A top view of the present invention; Figure 3 Schematic diagram of a three-phase Y-connected capacitor bank according to Embodiment 3 of the present invention; Figure 4 Schematic diagram of a three-phase D-connected capacitor bank according to Embodiment 3 of the present invention; Figure 5 This is a schematic diagram of a three-parallel-two-series capacitor bank according to Embodiment 3 of the present invention; Figure 6 This is a schematic diagram of a six-parallel capacitor bank according to Embodiment 3 of the present invention; Figure 7 It is a front schematic diagram of the capacitor bank of the present invention; Figure 8 is a top view schematic diagram of a capacitor bank of the present invention; Among them, 1. bushing; 2. capacitor; 3. insulating platform; 4. insulating support; 5. wiring; 51. first point; 52. second point; 53. third point; 54. fourth point; 55. fifth point; 6. equipotential line; 7. grounding wire of the base of the insulating support column. DETAILED DESCRIPTION

[0020] 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.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the invention is usually placed when used. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply 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.

[0023] When an element is referred to as being "disposed on" another element, it may be directly on the other element or there may also be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may also be a central element. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only embodiments. If the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but it can be slightly tilted.

[0024] It should be noted that similar reference numerals and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further defined and explained in the subsequent figures. In the description of the present invention, it is understood that the terms "include" and "comprise" indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their collections.

[0025] 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 technical field 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. As used in the specification of the present invention and the appended claims, the singular forms of "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise.

[0026] The present invention is described in detail below with reference to the accompanying drawings.

[0027] A test capacitor reactive power compensation device of the present invention comprises: an insulating platform 3, an insulating support 4 is connected to the bottom of the insulating platform 3, a plurality of capacitors 2 are placed in a single layer on the insulating platform 3; a bushing 1 is provided on the top of the capacitor 2, and the bushings 1 are connected by wiring 5; the shells of the capacitors 2 are connected by an equipotential line 6; and the bottom of the insulating support 4 is connected to an insulating support column base grounding wire 7. The capacitor 2 is placed vertically on the insulating platform 3. Optionally, the length of the insulating support 4 is less than 2m.

[0028] A reactive power compensation device for a capacitor for testing of the present invention comprises the following steps when in use: Before installation, the selection is carried out. According to the compensation capacity and test voltage, the appropriate number of capacitors and insulating supports matching the voltage level are selected, and the cross-sectional area of ​​the bare copper wire is matched with the compensation current.

[0029] During installation, the capacitor 2 is placed vertically on the insulating platform 3; The bushings 1 of the capacitors 2 are connected via the wiring 5 ; and the casings of the capacitors 2 are connected via the equipotential line 6 .

[0030] The bushing 1 of the present invention is the main insulating device of the capacitor. The lead wires of the internal capacitor plates are led out to the outside to ensure the insulation between the lead wires and between the lead wires and the capacitor casing, and at the same time play the role of fixing the lead wires. The capacitor 2 is used as the main body of the reactive power compensation device, and multiple units can be arranged vertically and placed on the insulating platform 3. The insulating platform 3 is used to support the platform of the entire capacitor. The insulating support column 4 is used to insulate and isolate the potential of the capacitor from the ground and ensure the stability of the entire capacitor. The current guide connecting line 5 is used to connect each capacitor in parallel and in series to form an effective current loop for reactive power compensation. The casing equipotential line 6 is used to connect the capacitor casings on the same platform to make the potentials exactly the same to prevent suspended discharge. The insulating support column base grounding wire 7 is used to fix the potential of the metal base of the insulating support column to avoid suspension.

[0031] The existing laboratory compensating parallel capacitor structure is a multi-layer tower with a height ranging from 5 meters to more than 10 meters, and a lift is required for maintenance. The single-layer platform structure of the present invention can maintain a height of less than 2 meters, greatly reducing the space height and maintenance difficulty. The single-layer platform structure enables the compensation capacitor to be placed vertically, and the series and parallel connections are directly connected using wires, saving space and cost.

[0032] Example 1 The capacitor 2 of the present invention is placed vertically instead of horizontally because of space limitation, which occupies too much space horizontally, making the second wiring difficult and unable to connect in a centralized manner; and the potential distance to the ground is reduced, so the best arrangement of the capacitor is to place it vertically. Due to the insulation characteristics of the capacitor 2, the insulation level of the terminal to the shell cannot be too high, otherwise it will cause insulation breakdown. Therefore, in the present invention, the potential level of the shell and the terminal of the capacitor 2 is kept not to exceed its maximum working voltage.

[0033] Specifically, in the present invention, the capacitor 2 is led out with fully insulated terminals to ensure the insulation level of the two led-out terminals to the housing.

[0034] The capacitor 2 includes a capacitor plate, a dielectric, a fuse, a casing and a sleeve 1. Each capacitor leads to two terminals. When multiple groups of capacitors are connected in parallel and in series, the capacitor terminals are connected through a conducting connecting line and connected to an external load. The capacitor casings are connected through equipotential lines to form an equipotential to prevent floating discharge.

[0035] Optionally, since the capacitor 2 of the present invention is not stacked, the weight per unit projected area is greatly reduced, and a thinner and lighter insulating support member 4 is used for insulating support.

[0036] Optionally, the insulating support member 4 is made of a composite material.

[0037] Optionally, the insulating support 4 is an insulator, which is made of a glass fiber resin core rod and an organic material sheath and shed skirt. It is characterized by small size, light weight, high tensile strength, and excellent anti-pollution flashover performance.

[0038] The insulating support member 4 has a base at the bottom, which is made of cast iron material. The insulating support member 4 is fixed to the ground by bolts. The ground is required to be clean and level, and have a certain strength to ensure the stability of the insulating support. The bases of all the insulating support members 4 at the bottom are grounded through the insulating support column base grounding wire 7 to prevent potential floating.

[0039] The insulating platform 1 is an insulating object, and the potential problem is not considered. However, the upper metal fixings fixed to the insulating support need to be connected to the capacitor shell through an equipotential line, but cannot be grounded because the shell has a certain potential. This method is simple, reliable, and clear at a glance.

[0040] The capacitor 2, the insulating platform 1 and the insulating pillar 4 constitute a compensation unit. Multiple compensation units can be placed according to the size of the site. The compensation units can be connected in parallel or in series, and can be connected to single-phase or three-phase output. Depending on the site, it can be arranged in a finished shape or a straight shape. The straight shape can save space, and the insulation distance is sufficient. The upper terminal is directly connected to the high-voltage line, and the bottom is supported and isolated by the insulating pillar, so as to minimize the volume. Each compensation unit can place multiple parallel capacitors 2 according to the size of the platform, and they are connected in parallel into groups. The number of series stages of each group is determined according to the insulation level of the pillar.

[0041] like Figure 1 As shown, when 2 strings are output, the voltage is 80kV, and potential analysis is required, such as Figure 4 As shown, red is 2-string connection wire 5 cables, and blue is shell equipotential connection wire 5 cables.

[0042] When used in 2 strings, the ground potential at the first point 51 is 80 kV, the ground potential at the second point 52 is 60 kV, the ground potential at the third point 53 is 40 kV, the ground potential at the fourth point 54 is 20 kV, and the ground potential at the fifth point 55 is 0. Since the insulation level of the insulating support 4 is 40 kV, when the operating voltage is 53.3 kV, the ground potential at the second point 52 is 40 kV.

[0043] Example 2 The rated voltage of a single shunt capacitor 2 used in this embodiment is 20 kV. An insulating wooden board of 1500 mm × 1100 mm × 40 mm is selected as a platform, and 6 platforms are placed according to the size of the site.

[0044] During layout, the number of compensation capacitors, the size and weight of each capacitor are determined first according to the compensation capacity. The combination and distance selection are determined according to the existing site. The size of the insulation platform is then determined to ensure the appropriate area size and thickness. Finally, the total weight is determined. Based on the total weight, appropriate insulation pillars are selected to ensure the pressure resistance and insulation strength, so as to obtain the optimal solution for the best insulation size and weight support.

[0045] like Figure 2 As shown, the parallel capacitor 2 placement platform is composed of insulating wooden boards and pillars. According to the platform size, 12 parallel capacitors 2 are placed on each platform, and insulating pillars 4 with a voltage level of 40kV are selected according to the space height. Six parallel capacitors 2 are connected in parallel into one group, and two groups are connected in series for output (up to 40kV).

[0046] Before making the capacitor compensation platform, it is necessary to measure the size of the connected high-voltage busbar to the ground and the lower space. According to the volume of a single capacitor and the required insulation distance, determine the distance coefficient between adjacent ones (one time the casing length), the distance coefficient of the upper and lower spaces (five times the casing distance in the upper part, twice the casing distance in the lower part), and the front and back distance coefficient (three times the casing distance plus a safety distance of 0.5 meters). It is calculated that the required space is smaller than the space that can be installed at present, so the number and capacity of capacitors that can be installed can be calculated.

[0047] Example 3 In this embodiment, when the capacitors are connected in three phases, two in parallel or two in series can be output. When connected in single phase, six in parallel or three in parallel and two in series can be output.

[0048] like Figure 3 As shown, the capacitor bank adopts three-phase Y connection (40kV), two capacitor banks are placed on each insulating platform 3, the capacitor banks of two insulating platforms 3 constitute one phase, and each phase capacitor bank consists of two parallel and two series.

[0049] like Figure 4 As shown, the capacitor bank is three-phase D-connected (40 kV), two capacitor banks are placed on each insulating platform 3, the capacitor banks of two insulating platforms 3 constitute one phase, and each phase capacitor bank consists of two parallel and two series.

[0050] Three-phase Y connection or three-phase D connection, using six insulation platforms 3, 72 capacitors, two insulation platforms 3 for one phase, a total of three phases, connected to the high-voltage bus through lead wires.

[0051] like Figure 5 As shown, the capacitor bank adopts single-phase (80kV), two capacitor banks are placed on each insulating platform 3, and the two capacitor banks are connected in series. The capacitor banks of the six insulating platforms 3 form three parallel and two series.

[0052] like Figure 6 As shown, the capacitor bank adopts single-phase (40kV), two capacitor banks are placed on each insulating platform 3, the two capacitor banks are connected in series, and the capacitor banks of six insulating platforms 3 form six parallels.

[0053] When six insulation platforms 3 are connected in parallel, all terminals on the same side are connected in parallel, so that a single head and tail can be formed and led to the high-voltage bus. When three in parallel and two in series, the three insulation platforms 3 on the left are connected in parallel, and the three insulation platforms 3 on the right are also connected in parallel, and then one side is short-circuited, and the other side terminals of each are led to the high-voltage bus.

[0054] Taking the insulating platform 3 as a unit, the three-phase can form two strings of Y connection, two parallel Y connection, two strings of D connection, and two parallel D connection; the single-phase can form six strings, five strings, four strings, three strings of two parallel, two strings of three parallel, and one parallel; the insulating platform 3 can form series and parallel connections inside to adapt to different voltage levels.

[0055] In order to prevent the insulating support 4 from being used beyond the tolerance level, a potential analysis is required. Taking the voltage level of the insulating support 4 selected in this embodiment as an example, when two insulating platforms 3 are connected in series (capacitors 2 use four series), the series voltage can reach 80kV, which is far beyond the tolerance level of the insulating support 40kV. How to improve the output efficiency of the capacitor 2 without exceeding the tolerance level of the insulating support 4 is extremely important. Because the rated voltage between the output terminal and the shell is 20kV, when adjacent capacitors 2 are connected in series, the shell is at the average of the lowest voltage and the highest voltage, which can maximize the output efficiency of the capacitor 2. Then, when the two groups of capacitors 2 of the second insulating platform 3 are connected in series, the voltage of the shell is as high as the 40kV tolerance voltage of the insulating support 4 of the insulating platform 3. Through calculation, it can be known that the shell voltage of the capacitor 2 of the second insulating platform 3 is 40kV, which is the series voltage of the three-level capacitor 2, that is, the voltage of each level is 13.3kV, so the four-level voltage is 53.3kV.

[0056] It can be seen that by connecting the casing and the equipotential line 6, it is possible to maximize the output efficiency of the capacitor 2 without exceeding the rated voltage. However, if the casing is completely grounded, or connected to the output terminal, or connected to the second-level capacitor terminal, the output efficiency of the capacitor 2 cannot be maximized.

[0057] Due to space and economic cost constraints, the insulation level of the insulating support 4 is set to 40kV. The most extreme case is a single-phase four-group capacitor 2 connected in series. Other wiring methods can basically make the efficiency of the capacitor 2 reach 100% due to the voltage reduction. For example, when there are three phases, two parallel and two strings, the maximum phase voltage output is 40kV, and the shell voltage to the ground is 30kV; when there are three phases and four parallel, the maximum phase voltage output is 40kV, and the shell voltage to the ground is 10kV; single-phase two parallel and three strings, the maximum phase voltage output is 60kV, and the shell voltage to the ground is 40kV; single-phase three parallel and two strings, the maximum phase voltage output is 40kV, and the shell voltage to the ground is 20kV. When the full capacity output is met, each insulation part will not exceed its own insulation level, achieving maximum cost performance.

[0058] The present invention can clearly understand the composition and connection mode of the entire architecture through a partial circuit schematic diagram. The six insulating platforms 3 can form three-phase Y connection, D connection, single-phase series and parallel output. The composition mode is diverse, forming a combination of different currents and voltages to meet the reactive power compensation requirements of various types of products. In a highly limited space, the inefficient waste of compensation capacity caused by the insufficient insulation distance caused by the use of knife switches and the insufficient connection mode is avoided.

[0059] Unless otherwise specified, the device elements involved in the above embodiments are all conventional device elements, and the structural settings, working modes or control modes involved are all conventional settings, working modes or control modes in the art unless otherwise specified.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in the field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A capacitor reactive power compensation device for testing, characterized in that: include: An insulating platform (3), the bottom of the insulating platform (3) is connected to an insulating support member (4), a plurality of capacitors (2) are placed in a single layer on the insulating platform (3); the top of the capacitor (2) has a bushing (1), the bushings (1) are connected via wiring (5); the shells of the capacitors (2) are connected via an equipotential line (6); the bottom of the insulating support member (4) is connected to an insulating support column base grounding wire (7).

2. A reactive power compensation device for capacitors for testing according to claim 1, characterized in that: The insulating support member (4) is an insulating support column, and the bottom of the insulating support member (4) has a metal base.

3. A reactive power compensation device for capacitors for testing according to claim 1, characterized in that: The capacitor (2) is placed vertically on the insulating platform (3), and the length of the insulating support (4) is less than 2 m.

4. A reactive power compensation device for capacitors for testing according to claim 1, characterized in that: The number of the insulating platforms (3) is greater than one, the multiple insulating platforms (3) are arranged in multiple groups, each group of insulating platforms (3) is arranged linearly, the capacitors (2) in the same group of insulating platforms (3) form a capacitor group, and the capacitors (2) in the same capacitor group are connected in parallel.

5. A reactive power compensation device for capacitors for testing according to claim 4, characterized in that: The capacitor groups are connected in star or delta connection to form a three-phase output, or multiple groups are connected in parallel or in series to form a single-phase output.

6. A test capacitor reactive power compensation device according to claim 1, characterized in that: The wiring (5) and the equipotential line (6) are both bare copper wires.

7. The reactive power compensation device for capacitors used in tests according to claim 1 is characterized in that: The insulating platform (3) is an insulating wooden board.

8. The reactive power compensation device for capacitors used in tests according to claim 1 is characterized in that: The capacitor (2) is an oil-filled capacitor.

9. The reactive power compensation device for capacitors used in tests according to claim 1, characterized in that: The capacity of the capacitor (2) is 50 kvar, 100 kvar, 200 kvar, 300 kvar or 500 kvar.

10. The method for using the reactive power compensation device for a test capacitor according to any one of claims 1 to 9, characterized in that: The following steps are involved: During installation, the capacitor (2) is placed vertically on the insulating platform (3); The bushings (1) of the capacitors (2) are connected via a wiring (5); and the casings of the capacitors (2) are connected via an equipotential line (6).

Images