CN2583867Y - High voltage motor reactive compensation device on spot - Google Patents

Abstract

The utility model relates to a reactive on-site compensation device connected in parallel with a high-voltage asynchronous motor, comprising a protective shell 8, a series main circuit arranged in the protective shell 8, and a detection and protection system for the series main circuit, wherein the series main circuit includes The harmonic suppression unit and the current detection system connected in series between the incoming cable 13 and the power capacitor 7 also include an isolation unit 1 connected in series between the incoming cable 13 and the harmonic suppression unit; the isolation unit 1 is a belt Isolation switch or vacuum load switch for grounding knife. This reactive on-site compensation device realizes the isolation from the device when the high-voltage motor is running by providing an isolating switch or a vacuum load switch in the high-voltage power input. The detection system in this device can be connected with the computer in the remote main control room to realize remote monitoring; the device is also equipped with a series reactor to suppress the harm of harmonics to the capacitor; since the device is compactly installed in a cabinet, It can be installed close to the motor, which can well meet the needs of various occasions.

Description

On-the-spot reactive power compensation device for high-voltage electric motor

technical field

The utility model relates to a high-voltage motor reactive power compensation device, in particular to a high-voltage motor reactive power on-site compensation device with an isolating switch that can be remotely controlled by a computer.

Background technique

The traditional high-voltage motor reactive power compensation device for compensating reactive power and improving power factor is directly connected in parallel with the high-voltage motor, and there is no power supply line isolation unit, that is, there is no line switch. When the motor is running, it is necessary to shut down the motor and exit the operation before checking or processing device failure; the traditional compensation device cannot be connected with the computer to realize remote monitoring, and single-phase capacitors are mostly used as power capacitors, and each phase requires a At least three sets are required, and six sets may be required if the capacity is slightly larger, and two sets are connected in parallel for each phase. In addition, the reactance rate of the reactors in the existing compensation devices is 6%, which cannot be configured according to the harmonics of the user grid.

Utility model content

The technical problem to be solved by the utility model is to construct a high-voltage motor reactive on-site compensation device by using high-voltage isolating switch, sensor, transmitter and computer technology to realize safe isolation and connection with the normal operating high-voltage motor, and further Realize the remote monitoring of the device itself.

The above-mentioned technical problems of the utility model are solved in such a way that a high-voltage motor reactive compensation device is constructed in parallel with the high-voltage motor, including a protective shell, a series main circuit located in the protective shell, and a detection and protection system for the series main circuit. The main circuit includes a harmonic suppression unit connected in series between the incoming cable and the power capacitor, and an isolation unit connected in series between the incoming cable and the harmonic suppression unit; the isolation unit can be an isolating switch with a grounding knife or vacuum load switch.

In the on-site reactive power compensation device for high-voltage motors provided according to the utility model, it is characterized in that the isolation unit is a vacuum load switch with a grounding knife, and also includes a current detection system and a temperature and humidity detection system, and the detection system signal transmission to the remote computer.

In the on-site reactive compensation device for high-voltage motors provided according to the utility model, it is characterized in that the harmonic suppression unit includes a three-phase iron core reactor, the protection system includes a high-voltage fuse and a lightning arrester, and the three-phase iron The core reactor, the high voltage fuse and the power capacitor are sequentially connected in series, the lightning arrester is grounded and connected in parallel with the series main circuit on the connection bus, and the power capacitor is a power capacitor with a built-in discharge resistor.

According to the on-site reactive power compensation device for high-voltage electric motors provided by the utility model, it is characterized in that the three-phase iron-core reactor adopts three-phase dry-type iron-core reactors, and reactors with different reactance rates are configured according to the harmonic conditions in the power grid ; When the 5th harmonic in the grid is large, configure a reactor with a reactance rate of 4.5%; when the 3rd harmonic in the grid is large, configure a reactor with a reactance rate of 12%.

In the on-site reactive power compensation device for high-voltage motors provided according to the utility model, it is characterized in that the current detection system includes a current transformer installed in the series main circuit and an indicator connected to the secondary output terminal of the current transformer Meters and current transducers.

In the reactive on-site compensation device for high-voltage motors provided according to the utility model, it is characterized in that the temperature and humidity detection system includes a temperature measuring sensor mounted on the upper part of the power capacitor housing and a temperature and humidity transmitter connected to it. The device also includes a humidity sensor and a temperature and humidity transmitter connected thereto.

In the on-site reactive compensation device for high-voltage electric motors provided according to the utility model, it is characterized in that the protective casing is a cabinet with a width of 1200 mm, a depth of 1400 mm and a height of 2600 mm.

Implementation of the high-voltage motor reactive power on-site compensation device provided by the utility model, when the isolation switch or the vacuum load switch is used to realize the operation of the high-voltage motor, the fault of the device can be checked and processed, and the impact on the user when checking and processing the fault can be reduced. Technology realizes telemetry and remote control of the device itself, so as to achieve the purpose of unattended. In addition, in order to achieve the configuration of a device of the present invention, the traditional compensation device requires at least two cabinets, one for the incoming line cabinet and one for the capacitor cabinet, while the utility model adopts a three-phase capacitor, which is small in size and has a built-in discharge resistor. It adopts a dry-type core three-phase reactor, which is small in size, and the high-voltage isolating switch or vacuum load switch has a grounding knife, which saves a grounding switch, so it can be installed in a cabinet.

Description of drawings

Fig. 1 is the electrical wiring diagram of the preferred embodiment provided by the utility model.

Fig. 2 is a schematic diagram of the physical connection of the preferred embodiment provided by the present invention.

Fig. 3 is a schematic diagram of the appearance of the preferred embodiment provided by the utility model.

Detailed ways

The reactive on-site compensation device for high-voltage motors provided by the utility model is realized by adopting the following structure: an isolation unit is set between the incoming cable 13 and the harmonic suppression link, and a current and temperature and humidity detection system is set in the device, and these detection systems are connected to the remote connected to the end computer.

The structure of the above-mentioned reactive power on-site compensation device can be realized by the following embodiments: as shown in Figures 2 and 3, the device includes a cabinet body 8, a high-voltage isolation switch GK1 connected to the incoming cable 13, and a three-phase core reactor connected in series with the isolation switch GK1 L2 also includes the connection bus 9 drawn from the three-phase iron core reactor L2, the special lightning arrester FV3 connected to the connection bus 9 and the ground at both ends, also includes the charged display sensor 4 and the connected live display H16, and also includes the connected bus 9 A current transformer TA5, a high-voltage fuse FU6 and a power capacitor C7 are connected in series in sequence, and a current measurement and display device PA15 is also included.

As shown in Figure 3, the thick solid line represents the main circuit, and the thin solid line represents the control and protection circuits. The inside of the dotted line is the schematic diagram of the part of the device required to realize remote computer monitoring. The computer is in the remote main control room. The working principle of this device is:

Isolation unit: The incoming line of the device adopts an isolating switch with a grounding knife or a vacuum load switch GK(1), which mainly isolates the device from the high-voltage motor. When the device needs to check, replace the fuse and deal with the fault, open the isolating switch GK(1). The grounding is closed, so that the residual charge on the power capacitor C (7) can be completely discharged, and when the operation is performed again, it is quite reliable for personal protection. It saves the procedure of manually hanging the ground wire and the hidden danger of poor contact of the ground wire. And it does not affect the operation of the motor, and the user can produce continuously. If the isolating switch is replaced with a vacuum load switch, the computer outputs the control signals of the contact switches J1 and J2 to control the opening and closing of the vacuum load switch, thus realizing the control of the device through the remote computer. The vacuum load switch also has a grounding knife, which can still ensure personal safety.

Harmonic suppression unit: According to the background situation of using the harmonics of the on-site power grid, the reactor L (2) is configured to suppress the harmonics and protect the power capacitor C (7). As the degree of automation in enterprises is getting higher and higher, especially the use of frequency conversion equipment, DC equipment, and electrochemical, electric furnace and other equipment, a large number of harmonics will be injected into the grid, and the grid itself is not perfect. Wave. These harmonics cause the power capacitor C (7) to overcurrent, generate heat, inaccurate capacity and shorten the service life, seriously endangering the safe operation of the power capacitor C (7). To cause the device to quit running and increase reactive power consumption. When the 5th harmonic of the power grid is large, configuring a reactor L(2) with a reactance rate of 4.5% can not only suppress the 5th harmonic and above, but also limit the closing inrush current. When the 3rd harmonic of the power grid is large, the reactor L(2) with a reactance rate of 12% can be configured to suppress the 3rd harmonic and closing current. The reactor L(2) adopts a dry-type three-phase iron core reactor, which is not only small in size, but also has a small loss.

Remote monitoring: 1. Current detection and control. The computer remote monitoring system is to convert the detection current of the current transformer TA (5) into a 5-20mA current signal through the current transmitter and send it to the remote computer. The current of the device can be checked on the computer to judge the power capacitor. Whether C(7) is overloaded, and whether the fuse FU(6) is blown. If an abnormality is found, the computer outputs a signal to connect the contact switch J2 to open the vacuum load switch, and the device shuts down for self-protection. 2. Temperature and humidity detection and control. Power capacitors are sensitive to temperature (including the ambient temperature and the temperature of the power capacitor itself). If the temperature exceeds the standard, it will accelerate the aging of the power capacitor insulation and seriously affect the service life. Therefore, a temperature sensor is installed, and the sensor signal is sent to the remote computer monitoring system through the temperature and humidity transmitter SB (12), and the computer is used to monitor the temperature change of the power capacitor to ensure the safe operation of the device. Humidity sensor and described temperature-humidity transmitter SB (12) form humidity detection system to detect the humidity in the cabinet, as humidity exceeds standard, can directly output exceeding standard signal by temperature-humidity transmitter SB (12) (also can pass computer Output signal) makes the contact switch J3 connected, supplies power to the heater FR (14), and the heater FR (14) generates heat to drive out moisture to ensure the operation of the device, so that the device can be used in places with high humidity. The power supply of the current transmitter LB (10) and the temperature and humidity transmitter SB (12) is provided by the regulated power supply WY (11).

Safety system: the electromagnetic lock (19) of charged indicator sensor H (4), high-voltage charged indicator H (16) and the cabinet constitutes a compulsory locking system. When the compensation cabinet has high-voltage electricity, the charged display H (16) has a display, and the cabinet door cannot be opened, so that the operating personnel cannot enter the electrified interval to ensure the safety of the operating personnel. Whether the device adopts a vacuum switch or an isolating switch, it is equipped with a grounding knife, which can reliably ground the power capacitor C (7) after the device is powered off. Reduce the hidden dangers of procedures and poor contact caused by manual connection of ground wires, and ensure the safety of maintenance personnel.

Protection system: Use special lightning arrester FV(3) to prevent operation overvoltage; high-voltage fuse FU(6) is used as internal fault protection of power capacitor; and the overvoltage protection device is not set, because the overvoltage standard of high-voltage motor is 6% , and the power capacitor overvoltage standard is 10%. Since the device and the motor use the same switch cabinet, the overvoltage protection of the motor meets the requirements. In addition to the above-mentioned isolating switch GK (1), charged indicator sensor H (4), high-voltage charged indicator H (16) and electromagnetic lock (19) of the cabinet, the device is fully protected, especially for the safety of personnel. compulsory protection.

As shown in Figures 2 and 3, in this device, the isolating switch or vacuum load switch and other devices are installed together in a cabinet, which has a compact structure and a small cabinet size. This device is a new type that can decide whether to set up temperature and humidity monitoring, choose different three-phase reactor L(2) and switch of isolation unit GK(1) according to the needs of the occasion, so as to realize multiple functions with a flexible scheme. compensation device.

Claims (10)

1. An on-site reactive power compensation device for a high-voltage motor, connected in parallel with the high-voltage motor, including a protective casing (8), a series main circuit located in the protective casing (8), and a detection and protection system for the series main circuit, and the series main circuit It includes a harmonic suppression unit and a current detection system connected in series between the incoming cable (13) and the power capacitor (7), and is characterized in that it also includes a series connection between the incoming cable (13) and the harmonic suppression unit isolation unit (1). 2. The on-site reactive compensation device for high-voltage motors according to claim 1, characterized in that the isolation unit (1) is an isolation switch or a vacuum load switch with a grounding knife. 3. The on-site reactive power compensation device for high-voltage motors according to claim 2, further comprising a current detection system and a temperature and humidity detection system, the detection output signals of which are sent to a remote computer. 4. The reactive power on-site compensation device for high-voltage motors according to claim 1, characterized in that the harmonic suppression unit includes a three-phase iron core reactor (2), and the protection system includes a high-voltage fuse (6) and The lightning arrester (3), the three-phase core reactor (2), the high voltage fuse (6) and the power capacitor (7) are connected in series in sequence, and the lightning arrester (3) is grounded to the series main The circuit is connected in parallel to the connection busbar (9), and the power capacitor (7) is a power capacitor with a built-in discharge resistor. 5. According to claim 4, the reactive power on-site compensation device for high-voltage motors is characterized in that the three-phase iron-core reactor (2) adopts a three-phase dry-type iron-core reactor, and the reactors with different reactance rates are configured according to the harmonic conditions in the power grid. reactor. 6. The on-site reactive compensation device for high-voltage motors according to claim 5, characterized in that, when the 5th harmonic in the power grid is relatively large, a reactor with a reactance rate of 4.5% is configured. 7. The on-site reactive power compensation device for high-voltage motors according to claim 5, characterized in that when the third harmonic in the power grid is large, a reactor with a reactance rate of 12% is configured. 8. The on-site reactive power compensation device for high-voltage motors according to claim 1, characterized in that the current detection system includes a current transformer (5) installed in the series main circuit and connected with the current transformer (5) An indicating instrument (15) and a current transmitter (10) connected to the secondary output end. 9. The on-site reactive compensation device for high-voltage motors according to claim 3, characterized in that the temperature and humidity detection system includes a temperature measurement sensor attached to the upper part of the power capacitor housing and a temperature and humidity transmitter connected to it The device also includes a humidity sensor and a temperature and humidity transmitter connected thereto. 10. The on-site reactive compensation device for high-voltage motors according to claim 1, characterized in that the protective casing (8) is a cabinet with a width of 1200 mm, a depth of 1400 mm and a height of 2600 mm.

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