Split-phase compensation intelligent capacitor

Abstract

The utility model provides a split-phase compensation intelligent capacitor, and belongs to the technical field of power systems. The capacitor is simple in structure, flexible to install, convenient to maintain and high in universality. A circuit breaker, a thyristor, a single-phase anti-harmonic reactor, a single-phase capacitor bank and a main control board of the capacitor are all arranged in a shell, the circuit breaker is connected with a system main loop, the circuit breaker is connected with the thyristor through a wire and supplies power to the thyristor, the thyristor is connected with the single-phase anti-harmonic reactor through a wire, and the single-phase capacitor bank is connected with the single-phase anti-harmonic reactor through a wire. The single-phase anti-harmonic reactor is connected with the single-phase capacitor bank through a wire, the main control board is externally in communication connection with an external cloud server to achieve data transmission, and the main control board is internally connected with the thyristor and the axial flow fan through wires to achieve opening and closing control. The capacitor is high in universality, can be used independently, can also be used in parallel with multiple capacitors, can be flexibly combined according to actual on-site conditions, meets on-site requirements, and can carry out effective reactive compensation on a three-phase unbalanced load.

Description

Technical Field

[0001] The utility model belongs to the technical field of power systems, and particularly relates to a single-phase compensation intelligent capacitor. Background Technique

[0002] With the continuous progress of power electronics, energy conservation, and control technologies, reactive power compensation, as an important part of power systems, is becoming more and more widely used in power systems. As a member of reactive power compensation products, intelligent capacitors are also becoming more and more popular.

[0003] Intelligent capacitors integrate advanced technologies such as modern measurement and control, power electronics, network communication, automation control, and power capacitors, and have the characteristics of better compensation effect, smaller volume, lower power consumption, lower price, more cost savings, more flexible use, more convenient maintenance, longer service life, and higher reliability, meeting the higher requirements of modern power grids for reactive power compensation.

[0004] In the current domestic market, the vast majority of intelligent capacitors use the three-phase common compensation method to compensate the power factor. Some use magnetic control switches as the switching switches of capacitors, and some use thyristors as the switching switches of capacitors. The disadvantage of this three-phase common compensation intelligent capacitor is that it cannot effectively compensate the reactive power for unbalanced three-phase loads. The three-phase common compensation intelligent capacitor defaults that the three-phase reactive currents in the system are equal, and the reactive power compensation capacity for each phase is also the same. For systems with a large number of unbalanced three-phase loads, when using three-phase common compensation intelligent capacitors, under-compensation and over-compensation problems will occur in two of the three phases, and the compensation effect is very poor.

[0005] When using a magnetic control switch as the switching switch of the capacitor, when the capacity of the intelligent capacitor reaches more than 20 kvar, the switching speed is slow, and it cannot track the reactive power changes of the system in time, and it is very easy to have problems of over-compensation or under-compensation. In a system with frequent reactive power changes, it is impossible to ensure that the system power factor always remains at a high level.

[0006] Due to the widespread application of various power rectification and commutation equipment and the application of a large number of nonlinear and time-varying loads, the harmonic content in the power system increases, resulting in an increase in electricity cost, more severe heating of transformers, malfunction of electronic equipment, and inability to operate capacitor compensation. More seriously, when the capacitor bank and the system generate parallel resonance, the current increases exponentially, causing the switch to trip, the fuse to blow, and the switching switch to burn. In addition, harmonic voltage accelerates the attenuation of capacitors and shortens their service life. Therefore, intelligent capacitors must have the function of suppressing harmonics, otherwise they cannot be used normally in many systems.

[0007] Generally, users adopt the method of manual regular inspection to ensure the safe operation of intelligent capacitors. The capacity of each intelligent capacitor generally does not exceed 50 kvar. Under normal circumstances, the number of intelligent capacitors installed by users is very large, so the work of manual inspection is extremely heavy. Moreover, manual regular inspection cannot promptly detect and handle problems that occur in the equipment. With the popularization of 5G and the development of narrowband Internet of Things (NBI-oT) technology, electrical equipment can already use wireless transmission technology to real-time feedback the equipment status to the terminal display device. Thereby reducing the work intensity of the inspection personnel, promptly detecting problems existing in the equipment, and ensuring the normal operation of the equipment. Therefore, having the function of remote wireless networking is an important direction for the development of intelligent capacitors. Summary of the Invention

[0008] In order to solve the problems existing in the above-mentioned background technology, the present utility model provides a single-phase compensation intelligent capacitor, which has a simple structure, flexible installation, convenient maintenance, and strong versatility.

[0009] The technical solution adopted by the present utility model to solve its technical problems is: a single-phase compensation intelligent capacitor, including a housing, a circuit breaker, a thyristor, a radiator, an axial flow fan, a single-phase anti-harmonic reactor, a single-phase capacitor bank, and a main control board. The circuit breaker, thyristor, radiator, axial flow fan, single-phase anti-harmonic reactor, single-phase capacitor bank, and main control board are all arranged inside the housing. The circuit breaker is connected to the main circuit of the system, and the circuit breaker is connected to the thyristor through a wire and supplies power to the thyristor. The thyristor is fixedly arranged on the radiator, and the thyristor is connected to the single-phase anti-harmonic reactor through a wire. The single-phase anti-harmonic reactor is installed on the bottom plate of the housing, and the single-phase anti-harmonic reactor is connected to the single-phase capacitor bank through a wire. The single-phase capacitor bank is fixedly arranged on the bottom plate of the housing. The radiator is fixed on the mounting plate of the housing, and the axial flow fan is placed at one end of the radiator. The main control board is externally communicatively connected to an external cloud server, and the main control board is internally connected to the thyristor and the axial flow fan respectively through wires.

[0010] The main control board includes an NB-IoT communication module and a controller. The NB-IoT communication module is communicatively connected to the cloud server. The controller is connected to the thyristor and the axial flow fan respectively through wires. The controller controls the opening and closing of the thyristor, and the controller drives the axial flow fan to start and stop.

[0011] The single-phase compensation intelligent capacitor further includes a signal transmission interface. The signal transmission interface is fixedly installed through the housing, and one end of the signal transmission interface located inside the housing is connected to the main control board.

[0012] The single-phase compensation intelligent capacitor further includes a display. The display is fixedly arranged on the outer wall of the housing. The display is connected to the main control board by a circuit. The controller controls the display to display content.

[0013] The single-phase anti-harmonic reactor is a reactor with a reactance rate of 7% or 14%.

[0014] The single-phase capacitor bank is composed of m capacitors connected in series, where m is a positive integer.

[0015] The NB-IoT communication module is selected with the model number M5311.

[0016] Advantages of the present utility model: This capacitor has the characteristics of flexible installation, convenient maintenance, good versatility, simple structure, excellent heat dissipation performance, etc. It has strong versatility and can be used alone or in parallel with multiple units. It can be flexibly combined according to the actual on-site situation to meet the on-site requirements. It can simultaneously achieve switching, harmonic suppression, good heat dissipation effect, and remote wireless networking functions, and can effectively perform reactive power compensation for unbalanced three-phase loads. Description of the Drawings

[0017] In the drawings:

[0018] Figure 1 is a schematic diagram of the internal structure of the present utility model Figure 1 ;

[0019] Figure 2 is a schematic diagram of the internal structure of the present utility model Figure 2 ;

[0020] Figure 3 is a rear view of the present utility model;

[0021] Figure 4 is a left view of the present utility model;

[0022] Figure 5 is a right view of the present utility model;

[0023] Figure 6 is a top view of the present utility model;

[0024] Figure 7 is a schematic diagram of the wiring relationship of the present utility model;

[0025] Figure 8 is a schematic diagram of the control principle relationship of the present utility model;

[0026] Figure 9 is the first background terminal display interface of the present utility model;

[0027] Figure 10 is the second background terminal display interface of the present utility model;

[0028] In the figure: 1. Shell; 2. Circuit breaker; 3. Thyristor; 4. Radiator; 5. Axial fan; 6. Single-phase anti-harmonic reactor; 7. Single-phase capacitor bank; 8. Display; 9. Main control board; 10. Signal transmission interface; 9-1. NB-IoT communication module; 9-2. Controller. DETAILED DESCRIPTION

[0029] The utility model is now described in further detail with reference to the accompanying drawings. The accompanying drawings are simplified schematic diagrams, which only illustrate the basic structure of the utility model in a schematic manner, and therefore only show the components related to the utility model.

[0030] A phase-splitting compensation intelligent capacitor comprises a housing 1, a circuit breaker 2, a thyristor 3, a radiator 4, an axial flow fan 5, a single-phase anti-harmonic reactor 6, a single-phase capacitor group 7 and a main control board 9. The circuit breaker 2, the thyristor 3, the radiator 4, the axial flow fan 5, the single-phase anti-harmonic reactor 6, the single-phase capacitor group 7 and the main control board 9 are arranged inside the housing 1. The circuit breaker 2 is located at the upper position inside the housing 1. The circuit breaker 2 is connected to the main circuit of the system. The circuit breaker 2 is connected to the thyristor 3 through a wire and supplies power to the thyristor 3. The thyristor 3 is fixedly arranged on the radiator 4. The tube 3 is connected to the single-phase anti-harmonic inductor 6 through a wire, and the single-phase anti-harmonic inductor 6 is installed on the bottom plate of the shell 1. The single-phase anti-harmonic inductor 6 is connected to the single-phase capacitor group 7 through a wire, and the single-phase capacitor group 7 is fixedly arranged on the bottom plate of the shell 1. The radiator 4 is fixed on the mounting plate of the shell 1, and the axial flow fan 5 is placed at one end of the radiator to improve the heat dissipation efficiency of the radiator 4. The main control board 9 is externally connected to the external cloud server for data transmission, and the main control board 9 is internally connected to the thyristor 3 and the axial flow fan 5 through wires to realize opening and closing control.

[0031] The main control board 9 includes an NB-IoT communication module 9-1 and a controller 9-2. The NB-IoT communication module 9-1 is connected to the cloud server for communication. The controller 9-2 is connected to the thyristor 3 and the axial flow fan 5 respectively through wires. The controller 9-2 controls the opening and closing of the thyristor 3 and drives the axial flow fan 5 to start and stop.

[0032] The thyristor 3 is an electronic switch used for switching the single-phase capacitor bank 7 and the single-phase anti-harmonic reactor 6. The thyristor 3 has the advantage of fast response speed and can complete switching within 20 milliseconds. It is suitable for sites with drastic load changes. Zero-crossing triggering can ensure that there is no impact or surge on the system, ensuring the stability of the system. The radiator 4 and the axial flow fan 5 can well solve the problem of heat dissipation of the thyristor 3.

[0033] By setting the upper voltage limit value and the lower voltage limit value in the controller 9-2, comparing the voltage in the main circuit of the system with the upper and lower voltage limit values, the process of controlling the turning on and off of the thyristor 3 is realized, so as to realize the input or cut-off of the single-phase anti-harmonic reactor 6. During the whole process, the controller 9-2 dynamically controls the switching to ensure that the voltage value of the main circuit of the system always meets the set value.

[0034] This device realizes the functions of phase-separated switching, harmonic suppression and remote wireless networking through the thyristor 3, the single-phase anti-harmonic reactor 6 and the main control board 9.

[0035] The phase-separated compensation intelligent capacitor further includes a signal transmission interface 10. The signal transmission interface 10 is fixedly installed on the housing 1. One end of the signal transmission interface 10 inside the housing 1 is connected to the main control board 9. After the current signal in the main circuit of the system is transmitted to the main control board 9 through the signal transmission interface 10, the main control board 9 transmits the system current signal to the next intelligent capacitor through the signal transmission interface 10. The phase-separated compensation intelligent capacitor of the present invention can work in parallel for multiple units and is used for power grid compensation.

[0036] The phase-separated compensation intelligent capacitor further includes a display 8. The display 8 is fixedly arranged on the outer wall of the housing 1. The display 8 is connected to the main control board 9 by wires, and the controller 9-2 controls the display 8 to display content.

[0037] The single-phase anti-harmonic reactor 6 selects a reactor with a reactance rate of 7% or 14%. At the site where the harmonic content of the 3rd, 5th and 7th harmonics is relatively large, it can well ensure the normal use of the intelligent capacitor, prevent the damage of harmonics to the capacitor, and can well extend the service life of the capacitor.

[0038] The single-phase capacitor bank 7 is composed of m capacitors connected in series, and m is a positive integer.

[0039] The NB-IoT communication module 9-1 selects the model M5311. The specific frequency of the NB-IoT communication module 9-1 is in seconds. The NB-IoT communication module 9-1 uploads and stores relevant information to the cloud server according to the Modbus485 communication protocol.

[0040] Working principle:

[0041] The present invention uses the thyristor 3 as an electronic switch, and utilizes the switching characteristics of the thyristor 3 to realize the switching of the capacitor. At the same time, the single-phase anti-harmonic reactor 6 adopted has a reactance rate of 7% or 14%. At the site where the harmonic content of the 3rd, 5th and 7th harmonics is relatively large, it can well ensure the normal use of the intelligent capacitor, prevent the damage of harmonics to the capacitor, and can well extend the service life of the capacitor.

[0042] The main device for the present utility model to achieve the remote wireless networking function is the NB-IoT communication module 9-1 integrated on the main control board. The NB-IoT communication module 9-1 uploads the relevant information of the intelligent capacitor to the cloud server at a specific frequency in seconds according to the Modbus485 communication protocol, and all data are stored in the cloud server. In the cloud server, each intelligent capacitor has a unique ID, and the cloud server system displays all the information on the visualization interface. Relevant personnel can read the information of the intelligent capacitor in real time through display terminals such as computers or mobile phones, and can trace historical information (such as Figure 8 and 9 shown). At the same time, relevant personnel can set each intelligent capacitor through the display terminal to ensure that all settings meet the on-site requirements. The NB-IoT communication module 9-1 in the main control board can achieve the remote wireless networking function, simplifies the manual inspection work, and solves the defect that the problems occurring in the equipment cannot be found and processed in time by regular manual inspections.

[0043] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, the present utility model can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A phase-splitting compensation intelligent capacitor, characterized in that: The invention comprises a housing (1), a circuit breaker (2), a thyristor (3), a radiator (4), an axial flow fan (5), a single-phase anti-harmonic reactor (6), a single-phase capacitor group (7) and a main control board (9), wherein the circuit breaker (2), the thyristor (3), the radiator (4), the axial flow fan (5), the single-phase anti-harmonic reactor (6), the single-phase capacitor group (7) and the main control board (9) are arranged inside the housing (1), the circuit breaker (2) is connected to the main circuit of the system, the circuit breaker (2) is connected to the thyristor (3) through a wire and supplies power to the thyristor (3), and the thyristor (3) is fixedly arranged on the radiator ( 4), the thyristor (3) is connected to a single-phase anti-harmonic reactor (6) through a wire, the single-phase anti-harmonic reactor (6) is mounted on the bottom plate of the housing (1), the single-phase anti-harmonic reactor (6) is connected to a single-phase capacitor group (7) through a wire, the single-phase capacitor group (7) is fixedly arranged on the bottom plate of the housing (1), the radiator (4) is fixed on the mounting plate of the housing (1), the axial flow fan (5) is arranged at one end of the radiator, the main control board (9) is externally connected to an external cloud server for communication, and the main control board (9) is internally connected to the thyristor (3) and the axial flow fan (5) respectively through wires.

2. The phase-splitting compensation intelligent capacitor according to claim 1 is characterized in that: The main control board (9) comprises an NB-IoT communication module (9-1) and a controller (9-2); the NB-IoT communication module (9-1) is connected to a cloud server for communication; the controller (9-2) is connected to the thyristor (3) and the axial flow fan (5) respectively via wires; the controller (9-2) controls the opening and closing of the thyristor (3); and the controller (9-2) drives the axial flow fan (5) to start and stop.

3. A phase-splitting compensation intelligent capacitor according to claim 1 or 2, characterized in that: The phase-splitting compensation intelligent capacitor further comprises a signal transmission interface (10), wherein the signal transmission interface (10) is fixedly mounted on the housing (1), and one end of the signal transmission interface (10) is located inside the housing (1) and is connected to the main control board (9).

4. The phase-splitting compensation intelligent capacitor according to claim 3 is characterized in that: The phase-splitting compensation intelligent capacitor also includes a display (8), which is fixedly arranged on the outer wall of the housing (1), the display (8) is connected to the main control board (9) by a circuit, and the controller (9-2) controls the display (8) to display content.

5. The phase-splitting compensation intelligent capacitor according to claim 1 is characterized in that: The single-phase anti-harmonic reactor (6) is a reactor with a reactance of 7% or 14%.

6. The phase-splitting compensation intelligent capacitor according to claim 1 is characterized in that: The single-phase capacitor group (7) is composed of m capacitors connected in series, where m is a positive integer.

7. The phase-splitting compensation intelligent capacitor according to claim 2 is characterized in that: The NB-IoT communication module (9-1) is selected as model M5311.

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