CN201408997Y - Low Voltage Smart Power Capacitor - Google Patents

Abstract

The utility model relates to an electrical product, that is, a low-voltage intelligent power capacitor, the main body of which includes an electronic switch, a single-chip microcomputer, a protection circuit and a capacitor, and is characterized in that: said capacitor C is connected in series with electronic switch K, said The electronic switch K is connected in parallel with the holding relay J, and the said single-chip microcomputer D has a voltage, current, temperature information processing unit and an output command unit. The products made by adopting the above technical scheme can determine the switching of the capacitor according to the sampling parameters of the line, the current impact is small when switching, the device is not easy to be damaged, the failure rate of the compensation equipment is greatly reduced, the service life is prolonged, and the maintenance is reduced Low cost, and has the advantages of simple structure, small space occupation, convenient on-site maintenance, etc. It is a substitute product for existing similar devices.

Description

Low Voltage Smart Power Capacitor

Technical field

The utility model relates to an electrical product, namely a low-voltage intelligent power capacitor.

Background technique

For inductive loads such as transformers, asynchronous motors, induction furnaces, and AC welding machines that require power supplies to provide reactive power, it is often necessary to use capacitors for reactive power compensation to improve the power factor, so as to reduce the power consumption and wiring caused by the transmission of reactive power. loss. Currently commonly used reactive power compensation methods include low-voltage individual compensation, low-voltage centralized compensation and high-voltage centralized compensation. Individual compensation is to connect single or multiple low-voltage capacitor banks in parallel with the electrical equipment according to the reactive power requirements of individual electrical equipment, and simultaneously switch and switch with the motor through the control and protection device. The low-voltage centralized compensation is to connect the low-voltage capacitor to the low-voltage bus side of the transformer through the low-voltage switch, and use the reactive power compensation switching device as the control and protection device to directly control the switching of the capacitor according to the reactive load on the low-voltage bus. The high-voltage centralized compensation is a compensation method in which parallel capacitor banks are directly installed on the high-voltage bus of the substation. Among them, low-voltage centralized compensation is more commonly used, especially in the user's switchboard where more shunt compensation capacitors are installed. This type of compensator is composed of a reactive power compensation controller, a switch, and a compensation device to form an execution device. The switching of power capacitors is controlled by a reactive power controller, which has high economy and practicability. However, the existing reactive power compensation devices also have disadvantages such as low intelligence, large current impact during switching, easy damage to devices, short service life, high cost, and difficult maintenance.

Contents of the invention

The purpose of the utility model is to provide a low-voltage intelligent power capacitor with high intelligence, low current when switching the capacitor, and the device is not easy to be damaged.

In order to accomplish the above purpose, the following technical scheme is adopted: a low-voltage intelligent power capacitor is developed, and its main body includes an electronic switch, a single-chip microcomputer, a protection circuit and a capacitor. Its characteristics are: the capacitor is connected in series with the electronic switch, the electronic switch is connected in parallel with the holding relay, and the single-chip microcomputer has a voltage, current, temperature information processing unit and an output command unit. When working, the single-chip microcomputer analyzes and compares the signals of the sampling detection circuit and the protection circuit, and then sends an instruction to the electronic switch, and automatically switches the compensation capacitor when the voltage crosses zero.

Said electronic switch is made up of thyristor devices.

Said electronic switch is composed of IGBT devices.

There are three reactive power compensator capacitors, which are connected to the three-phase power supply line by star connection.

There are three reactive power compensator capacitors, which are connected to the three-phase power supply line in a delta connection.

Said protection circuit is a current sampling circuit, a voltage sampling circuit and a line temperature sensor.

The low-voltage intelligent power capacitor made by the above technical scheme can determine the switching of the capacitor according to the sampling parameters of the line, realizing intelligent and programmed control, the current impact is small when switching, the device is not easy to damage, and the compensation equipment is greatly reduced. The failure rate is high, the service life is prolonged, the maintenance cost is reduced, and it has the advantages of simple structure, small space occupation, and convenient on-site maintenance. It is a substitute for existing similar devices.

Description of drawings

Fig. 1 is a structural diagram of an embodiment;

Fig. 2 is a structural diagram of an embodiment;

Fig. 3 is a structural diagram of an embodiment;

Fig. 4 is a kind of working status diagram of this embodiment;

Fig. 5 is another working state diagram of this embodiment.

Detailed ways

An embodiment is introduced in conjunction with the accompanying drawings: as shown in Figure 1, this device is connected in series with an electronic switch K in the circuit of the compensation capacitor C, and the electronic switch K is connected in parallel with the holding relay J. The trigger terminals S1 and S2 of the electronic switch and the two ends S3 and S4 of the driving coil of the holding relay J are all connected to the single-chip microcomputer D. The sampling signals of voltage detection circuit V, current detection circuit I and temperature sensor F are added to S5-S7 of single-chip microcomputer D. Connect the above-mentioned device to the three-phase circuit, the single-chip microcomputer analyzes and calculates the power factor on the line, and controls the electronic switch through the zero-crossing trigger circuit to realize automatic switching of the capacitor C.

Figure 2 presents a thyristor electronic switch consisting of two antiparallel thyristors D1 and D2. Its trigger terminals S1 and S2 are connected to the single-chip microcomputer D.

Figure 3 introduces an IGBT electronic switch, which consists of IGBT devices. Its trigger terminals S1 and S2 are connected to the single-chip microcomputer D.

Figure 4 introduces a working state, three capacitors are delta connected, two of which are connected with electronic switches controlled by a single-chip microcomputer, forming a reactive power compensation circuit.

Figure 5 introduces another working state. Three capacitors are connected in a star shape. Each capacitor is connected to an electronic switch controlled by a single-chip microcomputer to form a reactive power compensation circuit.

Its working principle is: connect the above-mentioned device to the three-phase circuit, calculate the real-time power factor by collecting the voltage of the circuit, and submit it to the voltage zero trigger in the single-chip microcomputer to trigger the turn-on and turn-off actions of the thyristor or IGBT device to realize Capacitor C input or removal.

Claims (6)

1. A low-voltage intelligent power capacitor, its main body includes electronic switch, single-chip microcomputer, protection circuit and capacitor, it is characterized in that: said capacitor C is connected in series with electronic switch K, said electronic switch K is connected with holding relay J In parallel, said single-chip microcomputer D has a voltage, current, temperature information processing unit and an output command unit. 2. The low-voltage intelligent power capacitor according to claim 1, characterized in that: said electronic switch K is composed of a thyristor device. 3. The low-voltage intelligent power capacitor according to claim 1, characterized in that: said electronic switch K is composed of IGBT devices. 4. The low-voltage intelligent power capacitor according to claim 1, characterized in that: there are three capacitors C, which are connected to the three-phase power supply line by star connection. 5. The low-voltage intelligent power capacitor according to claim 1, characterized in that: there are three capacitors C, which are connected to the three-phase power supply line by a delta connection. 6. The low-voltage intelligent power capacitor according to claim 1, characterized in that: said protection circuit is a current sampling circuit i, a voltage sampling circuit v and a circuit temperature sensor f.

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