CN201204459Y - Intelligent multi-control low-voltage automatic reactive power compensation device - Google Patents

Abstract

An intelligent multi-control low-voltage automatic reactive power compensation device, including a low-voltage reactive power automatic compensation controller and multiple capacitor cabinets with built-in compensation capacitor branches. The special feature is: in each compensation capacitor branch A compound switch is connected in series, and a changeover switch is connected to the output end of the low-voltage reactive power automatic compensation controller. One output end of the changeover switch is connected to a compound switch in a capacitor cabinet, and the other output end of the changeover switch is connected to a An intermediate relay, the normally open contacts of the intermediate relay are respectively connected to the compound switches in the remaining multiple capacitor cabinets. The advantages are: small impact on the grid, reduced reactive power loss, low power, no waveform distortion; single and multiple compensation cabinets can be switched at will, thus reducing costs, improving the power factor of the grid, small size and high compensation accuracy.

Description

Intelligent multi-control low-voltage automatic reactive power compensation device

technical field

The utility model relates to a low-voltage reactive power automatic compensation device, in particular to an intelligent multi-control low-voltage automatic reactive power compensation device.

Background technique

The previous low-voltage reactive power automatic compensation device adopts a low-voltage reactive power automatic compensation controller, and switches through contactors. This will generate a large inrush current, which will cause interference to the power grid; due to the arc phenomenon of the main contact of the contactor at the moment of switching the capacitor, the main contact of the contactor will be burned, which will affect the normal operation of the reactive power compensation device; due to the action of the contactor The speed is slow and the life is limited, so it is not suitable for occasions that require fast and frequent switching of compensation capacitors.

In recent years, the problem of switching reactive power compensation capacitor devices with contactors has been better solved by adopting low-voltage reactive power automatic compensation controllers and switching compensation capacitor devices through thyristors. Since the thyristor is a non-contact switch, its service life can be very long, and the input time of the thyristor can be precisely controlled, and the compensation capacitor can be connected to the power grid quickly and without impact, which greatly reduces the impact on the power grid and protects the compensation capacitor. . However, there are two main problems with the thyristor. One is the power consumption problem. Since the thyristor has a certain voltage drop when it is turned on, it will produce a large active power loss when working for a long time. The heat generated requires a fan to solve the problem of ventilation and heat dissipation or cooling. The water system reduces the temperature of the thyristor, which increases the cost of the device and occupies a large area; the second is that the crossover distortion of the thyristor causes the current waveform to be distorted, and harmonic currents are generated, which increases the damage rate of the capacitor.

In addition, the existing low-voltage reactive power automatic compensation device divides capacitors into several circuits for switching, and each circuit has one or more capacitors, which are controlled by a low-voltage reactive power automatic compensation controller, and the capacitors are switched sequentially according to the principle of voltage priority. When there are multiple capacitors in each circuit, the number of switching capacitors cannot be adjusted at any time. If the load is small, overcompensation may easily occur, which will have a negative impact on the power grid.

Contents of the invention

The purpose of this utility model is to solve the above-mentioned problems existing in the prior art, to provide a small impact on the grid, reduce reactive power loss, low power, no waveform distortion, reduce costs, improve the power factor of the grid, small size and compensation High-precision intelligent multi-control low-voltage automatic reactive power compensation device.

The utility model is realized in this way: it has a low-voltage reactive power automatic compensation controller and a plurality of capacitor cabinets with compensation capacitor branches inside, and its special feature is: a composite switch is connected in series in each compensation capacitor branch, A transfer switch is connected to the output end of the low-voltage reactive power automatic compensation controller, and one output end of the transfer switch is connected to a compound switch in a capacitor cabinet, and the other output end of the transfer switch is connected to an intermediate relay. The normally open contacts of the intermediate relays are respectively connected to the corresponding composite switches in the rest of the capacitor cabinets.

The device adopts a low-voltage reactive power automatic compensation controller, according to comprehensive factors such as voltage, current, reactive power, power factor, etc., through the conversion of the transfer switch, directly controls a single capacitor or controls multiple capacitors through an intermediate relay, so that the intelligent compound The switch is switched on and off, which realizes one trigger signal to control multiple capacitors, which can be used for single-cabinet switching or multi-cabinet switching, which reduces the cost, reduces the volume, improves the power factor of the grid, and reduces reactive power loss. , increasing the economic benefits of the enterprise. The function of putting the compensation capacitor into the grid or disconnecting it from the grid without impact reduces the interference caused by the impact current to the grid, speeds up the switching speed, prolongs the service life, reduces reactive power loss, and avoids the distortion of the current waveform. The reliability of the low-voltage reactive power compensation device is improved, the energy loss is reduced, the compensation accuracy is the highest, and the line is kept in the best state. The switching switch of the device has no special requirements on the signal from the reactive power compensation controller, and is relatively easy to realize. Even the existing reactive power compensation cabinet can be applied with a little modification, so it can be popularized in a large area.

Description of drawings

Fig. 1 is a schematic circuit diagram of the utility model.

Detailed ways

As shown in the figure, the utility model has a low-voltage reactive power automatic compensation controller 1 and a plurality of capacitor cabinets 2 with compensation capacitor branches built in. The compensation capacitor branches are composed of vacuum circuit breakers QF, fuses connected in series FU, reactor L, composite switch FK, thermal relay KR, capacitor C, current transformer TA, and lightning arrester FV are composed, and the output terminal of low-voltage reactive power automatic compensation controller 1 is connected with transfer switch SA, and the transfer switch SA One output end of one capacitor cabinet 2 is connected to the composite switch FK, and the other output end of the transfer switch SA is connected to an intermediate relay KA. The corresponding composite switch FK is connected, and the number of the multiple capacitor cabinets 2 can be two to three or more. The input end of the low-voltage reactive power automatic compensation controller 1 is connected to the input end of each compensation capacitor branch as the input end 3 of the intelligent multi-control low-voltage automatic reactive power compensation device.

When connecting, connect the input terminal 3 of the device with the output terminal of the switch cabinet. When putting in capacitors, the low-voltage reactive power automatic compensation controller 1 sends a signal to the transfer switch SA first, and when the load is small, the transfer switch is transferred to a single capacitor cabinet, and the signal sent by the low-voltage reactive power automatic compensation controller 1 is transmitted through the transfer switch SA. For the composite switch FK in the single capacitor cabinet 2, after the composite switch FK is closed, the capacitor C is put into the power grid; when the load is heavy, the transfer switch SA is transferred to the remaining multiple capacitor cabinets 2, and the low-voltage reactive power automatic compensation controller The signal sent by 1 is sent to the intermediate relay KA, and the normally open contact of the intermediate relay KA is closed, that is, according to the design action sequence, it sends a signal to the composite switch FK in the capacitor cabinet 2 respectively. After the composite switch FK is closed, the capacitor C is put into operation. in the grid.

Claims (1)

1. An intelligent multi-control low-voltage automatic reactive power compensation device, including a low-voltage reactive power automatic compensation controller and a plurality of capacitor cabinets with built-in compensation capacitor branches, characterized in that: in each compensation capacitor branch A compound switch is connected in series, and a changeover switch is connected to the output end of the low-voltage reactive power automatic compensation controller. One output end of the changeover switch is connected to a compound switch in a capacitor cabinet, and the other output end of the changeover switch is connected to a An intermediate relay, the normally open contacts of the intermediate relay are respectively connected to the corresponding compound switches in the remaining multiple capacitor cabinets.

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