Capacitance compensation cabinet with active power filter (APF) function

Abstract

A capacitance compensation cabinet with an active power filter (APF) function comprises a cabinet body, the cabinet body is sequentially provided with a cabinet top main bus chamber, a main switch chamber, a capacitor reactor installation chamber and an APF module installation compartment from top to bottom, the cabinet top main bus chamber is internally provided with a lap-joint bar penetrating through other chambers, the main switch chamber is provided with a circuit breaker, and the APF module installation compartment is provided with an APF module. The circuit breaker is electrically connected with the lap joint bar, an active power filter (APF) module is arranged in the APF module installation compartment and is electrically connected with the lap joint bar, a plurality of capacitors and reactors are arranged in the capacitor reactor installation chamber, a branch busbar is arranged at the output end of the circuit breaker and is connected with a plurality of fuses, and the branch busbar is electrically connected with the fuse. Each fuse is connected with a corresponding combination switch, and each combination switch corresponds to a group of reactors and capacitors.

Description

Technical Field

[0001] The utility model relates to the field of compensation cabinets, in particular to a capacitor compensation cabinet with an active filtering (APF) function. Background Art

[0002] Currently, inductive and nonlinear loads are increasing in distribution networks. In general, asynchronous motors account for approximately 70% of inductive loads in industrial enterprises. If reactive power accounts for a large proportion and is not compensated, the power factor of the grid will decrease, leading to increased line and voltage losses. Static compensation is currently the most widely used method for reactive power compensation.

[0003] With the large number of high-power power electronic devices put into operation in the power grid, harmonics have been recognized as "pollution" and "public hazards" of the power system. Harmonic problems and harmonic management issues have attracted more and more attention with the development of the power system. In recent years, with the country's attention to harmonics in the power grid, traditional passive filters can only be effective for a few specific harmonics in the power grid, and are very likely to resonate with other filter branches of the system. In addition, there are a series of shortcomings such as large consumables and large size, which makes it inconvenient to use and install. At this time, active power filters (APFs) were born with the large-scale production of high-power insulated gate bipolar transistors (IGBTs) in recent years. APFs overcome the above shortcomings and can compensate for any odd harmonics within the 2-50th order.

[0004] The existing solution is that the active power filter (APF) cabinet and the capacitor compensation cabinet must be installed separately on two sides of the cabinet. Now the urban land area is tight, which is a great waste of land resources. In addition, the investment in industrial consumables increases, non-ferrous metals are wasted, and the integration is not high. Utility Model Content

[0005] In order to solve the above problems, the present technical solution provides a capacitor compensation cabinet with active filtering APF function.

[0006] To achieve the above purpose, the technical solution is as follows:

[0007] A capacitor compensation cabinet with an active power filter (APF) function comprises a cabinet body, wherein the cabinet body is provided with a cabinet top main busbar chamber, a main switch chamber, a capacitor reactor installation chamber and an APF module installation compartment in sequence from top to bottom; a bonding bar that runs through other chambers is provided in the cabinet top main busbar chamber; a circuit breaker is provided in the main switch chamber, and the circuit breaker is electrically connected to the bonding bar; an active power filter (APF) module is provided in the APF module installation compartment, and the active power filter (APF) module is electrically connected to the bonding bar; a plurality of capacitors and reactors are provided in the capacitor reactor installation chamber; a branch busbar is provided at the output end of the circuit breaker, and the branch busbar is connected to a plurality of composite switches; each composite switch is connected to a corresponding fuse; and each fuse corresponds to one of the reactors and capacitors.

[0008] In some embodiments, a heat dissipation fan is provided at the upper end of the cabinet, and heat dissipation fans are provided at the lower end and rear end of the cabinet, and the cabinet is provided with heat dissipation holes corresponding to the heat dissipation fans.

[0009] In some embodiments, a terminal block for wiring is provided in the cabinet.

[0010] In some embodiments, the cabinet also includes an electrical part, in which one end of the strapping bar is connected to the load side, and the other end is also connected to the upper contact of the circuit breaker. The lower contacts of the circuit breaker are respectively connected to multiple fuses through branch busbars, and each fuse is connected to a compound switch, a reactor and a capacitor in turn. The branch busbar is also connected to the load side through an active filter APF module.

[0011] In some embodiments, the circuit breaker lower contact is also grounded through a surge protector.

[0012] The beneficial effects of this application are:

[0013] This application combines the active power filter (APF) cabinet and static VAR compensation cabinet with a comprehensive centralized filter and compensation control cabinet to complete the related functions. Compared with traditional solutions, it not only saves space and non-ferrous metals in the cabinet and power room, but also highly integrates static VAR compensation and active power filtering functions into a multifunctional low-voltage cabinet.

[0014] This solves a series of problems with the traditional APF cabinet and reactive power compensation cabinet, which require separate cabinets, resulting in a serious waste of space and materials. It also addresses a series of shortcomings, such as the traditional passive filter being only effective against a few specific harmonics in the power grid, being prone to resonance with other filter branches in the system, and having a large number of consumables, large size, and inconvenience in use and installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments.

[0016] Figure 1 This is a schematic diagram of the structure of the embodiment of the utility model Figure 1 ;

[0017] Figure 2 This is a schematic diagram of the structure of the embodiment of the utility model Figure 2 ;

[0018] Figure 3 This is a schematic diagram of the structure of the embodiment of the utility model Figure 3 ;

[0019] Figure 4 This is a schematic diagram of the structure of the embodiment of the utility model Figure 4 ;

[0020] Figure 5 It is a schematic diagram of the electrical structure of an embodiment of the present utility model. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] Please refer to Figure 1-5 As shown, a capacitor compensation cabinet with active filtering APF function includes a cabinet body, wherein the cabinet body is provided with a cabinet top main busbar room, a main switch room, a capacitor reactor installation room and an APF module installation compartment in sequence from top to bottom, the cabinet top main busbar room is provided with a bonding bar running through other rooms, the main switch room is provided with a circuit breaker, the circuit breaker is electrically connected to the bonding bar, the APF module installation compartment is provided with an active filtering APF module, which is electrically connected to the bonding bar, the capacitor reactor installation room is provided with a plurality of capacitors and reactors, the output end of the circuit breaker is provided with a branch busbar, the branch busbar is connected to a plurality of composite switches, each of the composite switches is connected to a corresponding fuse, and each fuse corresponds to one of the reactors and capacitors.

[0023] Specifically, a heat dissipation fan is provided at the upper end of the cabinet, and heat dissipation fans are provided at the lower end and the rear end of the cabinet. The cabinet is provided with heat dissipation holes corresponding to the heat dissipation fans.

[0024] Specifically, a terminal block for wiring is provided in the cabinet.

[0025] Specifically, the cabinet also includes an electrical part, in which one end of the bonding bar is connected to the load side, and the other end is also connected to the upper contact of the circuit breaker. The lower contacts of the circuit breaker are respectively connected to multiple fuses through branch busbars. Each fuse is connected to a compound switch, a reactor and a capacitor in turn. The branch busbar is also connected to the load side through an active filter APF module.

[0026] Specifically, the lower contact of the circuit breaker is also grounded through a surge protector.

[0027] The overall solution of this application is to transform the traditional reactive power compensation cabinet through cabinet modification and full utilization of space. It also integrates the design of the filtering and compensation schematics, and deeply integrates the active power filtering function into the static reactive power compensation cabinet. The complete technical solution of "a new capacitor compensation cabinet with active power filtering (APF) function" mainly describes the shell structure and electrical principles of this product in detail as follows for easy analysis. This application uses a 150A APF + 5 100kvar capacitor reactor group for detailed explanation.

[0028] Structurally, the cabinet body is constructed using a C-profile frame joined together by bolts. The cabinet features ventilation mesh doors at the front and rear. The interior is divided into four main sections: a main busbar compartment at the top, a main switch at the front, a functional module for installing capacitors and reactors, and compartments for installing branch strips and APF modules. These compartments form a closed, armored metal cabinet with standard dimensions of 1000mm wide, 1000mm deep, and 2200mm high. The main components installed in the cabinet include a 1000A / 3P electronic molded case circuit breaker, a surge protector, a 150-ampere APF module, five sets of branch compensation capacitors and reactor modules, a centralized filter compensation controller, and a sampling current transformer.

[0029] Considering that there are many components inside the cabinet, and most of them are heat-generating devices, the overall layout of the cabinet is designed to install the main switch at the lower end of the busbar compartment, with the APF module placed side by side with the switch. The branch busbar, fuse, compound switch, reactor, and capacitor are installed in the lower half of the cabinet from top to bottom. The compound switch and reactor are placed in the middle of the cabinet; the capacitor is placed at the bottom of the cabinet. The heat in the cabinet goes upward and gathers at the top of the cabinet. Therefore, a large number of heat dissipation holes are opened on the cabinet top plate and cabinet door, and cooling fans are installed on the front and back surfaces. The fan on the lower front door of the cabinet sends cold air in, and the fans on the top and upper rear door of the cabinet draw hot air out. This ensures that the temperature of the heat-generating parts of the above devices drops instantly, thereby ensuring the safe operation of this cabinet.

[0030] Electrically, the entire cabinet is installed between the incoming cabinet and the feeder cabinet. The horizontal main busbar of the low-voltage panel cabinet passes through the main busbar compartment on the top of the cabinet. The vertical bonding bus draws power from the horizontal main busbar to the upper end of the main circuit breaker QF. After passing through this circuit breaker, it uses the branch busbar in this cabinet. All capacitors, reactors, and APFs in the cabinet are electrically connected to this branch busbar with cables.

[0031] The aforementioned 1000A / 3P electronic molded case circuit breaker serves as the primary protection for the capacitor reactor and APF module. The other five groups of branch compensation capacitors and reactor modules each have a fuse at the front end to protect them from overload and short circuit. The APF is a separate metal-enclosed module, which also has a fast-acting fuse inside to protect it from overload and short circuit. A surge protector is also installed under the main switch to discharge current when lightning strikes the lines in the distribution cabinet, providing overvoltage protection for the entire cabinet.

[0032] This application deeply integrates the controllers of the capacitor compensation and filtering modules into a centralized filtering and compensation controller. This controller has a Chinese touch-screen LCD and a user-friendly human-machine interface. For current sampling, only one set of sampling current transformers is required. These transformers are installed on the main busbar in the main busbar compartment. For ease of installation and maintenance, these transformers are all open-type. During installation, there is no need to pass through the entire copper busbar. Instead, the transformers are opened, clamped on the main busbar, and then closed and tightened.

[0033] APF uses advanced IGBT as the core filtering device, so its response time is in the millisecond level. The centralized filtering compensation controller can perform real-time filtering according to the degree of harmonic current distortion in the power grid, and correct the distorted current waveform to a standard waveform, thereby reducing the damage of harmonics to the user-side electrical load. Since the harmonic current in conventional power distribution is not large, a 150A APF real-time dynamic compensation can meet the needs of most power grids. Of course, it can be increased to 2 to 3 150A modules according to actual needs. The power factor in conventional power grids is mainly low, and a large capacity of reactive power is required for compensation. Therefore, this cabinet is equipped with 5 100kvar capacitor reactors for reactive power compensation; reactive compensation adopts contactless composite switch. This centralized filter compensation controller can also judge the power factor of the power grid. When the power factor of the power grid is lower than the set value, the corresponding contactless composite switch can be turned on to energize this capacitor reactor group and connect it to the power grid for reactive compensation to improve the power factor and reduce the reactive loss of the power grid; the entire cabinet uses a centralized filter compensation controller to simultaneously realize dynamic filtering and static reactive compensation functions; thus, one cabinet can realize both filtering and static compensation functions.

[0034] The technical effects of this solution are:

[0035] This application uses a comprehensive centralized filtering and compensation control cabinet to complete the two functions of active filtering and static reactive compensation; and the devices and functions that require two cabinets to install are now installed in one cabinet; the filtering and compensation functions are highly integrated in the distribution cabinet, realizing multiple uses in one cabinet, and deeply integrating the principles of the two functions to achieve multiple uses in one machine; a multifunctional filtering and compensation cabinet that integrates static reactive compensation and active power filtering functions is realized;

[0036] Compared with traditional low-voltage distribution cabinets, this solution not only saves one distribution cabinet in terms of material usage, but also greatly saves the manufacturing cost of raw materials, such as steel, copper wire and other non-ferrous metals. Therefore, when the user's power room space is limited, this solution can well meet the needs of users with limited power room space.

[0037] Due to the limited space inside the cabinet and the large number of devices installed, the reasonable layout of this structure is not only conducive to the heat dissipation of the cabinet, but also has high space utilization, small size, beautiful appearance and easy maintenance; it can make better contributions to energy saving in the power grid and improving the quality of power.

[0038] The above description is only a preferred embodiment of the present application and is not intended to limit the scope of implementation of the present application. Other embodiments whose principles and basic structures are the same or similar to those of the present application are within the scope of protection of the present application.

Claims

1. A capacitor compensation cabinet with active filter APF function, characterized in that: The invention comprises a cabinet body, wherein the cabinet body is provided with a cabinet top main busbar room, a main switch room, a capacitor reactor installation room and an APF module installation compartment in order from top to bottom; a bridge bar (2) running through other rooms is provided in the cabinet top main busbar room; a circuit breaker (1) is provided in the main switch room; the circuit breaker (1) is electrically connected to the bridge bar (2); an active filter APF module (3) is provided in the APF module installation compartment; the active filter APF module (3) is electrically connected to the bridge bar (2); a plurality of capacitors (4) and reactors (5) are provided in the capacitor reactor installation compartment; a branch busbar (6) is provided at the output end of the circuit breaker (1); the branch busbar (6) is connected to a plurality of composite switches (7); each composite switch (7) is connected to a corresponding fuse (8); and each fuse (8) corresponds to one of the reactors (5) and capacitors (4).

2. The capacitor compensation cabinet with active power filter (APF) function according to claim 1 is characterized in that: A heat dissipation fan (9) is provided at the upper end of the cabinet body, and the heat dissipation fans (9) are provided at the lower end and the rear end of the cabinet body, and the cabinet body is provided with heat dissipation holes corresponding to the heat dissipation fans (9).

3. The capacitor compensation cabinet with active power filter (APF) function according to claim 2 is characterized in that: A terminal block (10) for wiring is provided in the cabinet.

4. The capacitor compensation cabinet with active power filter (APF) function according to claim 3 is characterized in that: The cabinet also includes an electrical part, in which one end of the bonding bar is connected to the load side and the other end is also connected to the upper contact of the circuit breaker. The lower contacts of the circuit breaker are respectively connected to multiple fuses through branch busbars. Each fuse is connected to a composite switch, a reactor and a capacitor in turn. The branch busbar is also connected to the active filter APF module.

5. The capacitor compensation cabinet with active power filter (APF) function according to claim 4 is characterized in that: The lower contacts of the circuit breaker are also grounded through the surge protector.

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