CN201629502U - Low-voltage distribution transformer reactive power compensation integrated box - Google Patents

Abstract

The utility model discloses a low-voltage distribution transformer reactive power compensation comprehensive box, which comprises a box body, and the box body includes a switch room and a capacitor room arranged side by side; The utility model also includes a switching automatic control unit, which is connected with the measurement sampling current transformer, compensation sampling current transformer and capacitor respectively. The compensation devices are connected to each other. The utility model integrates the functions of overload, short circuit, leakage, phase failure, zero failure protection, reactive power compensation measurement, low voltage isolation, watt-hour meter, load test recorder, etc., and effectively solves the problem of bench configuration. A series of problems encountered in installing multiple single-function devices on the low-voltage side of the transformer has the advantages of improving the safety and reliability of the low-voltage side of the bench-type distribution transformer and reducing the overall cost.

Description

Low-voltage distribution transformer reactive power compensation integrated box

technical field

The utility model relates to a reactive power compensation integrated box for a low-voltage distribution transformer of an intelligent grid.

Background technique

At present, outdoor distribution boxes suitable for the low-voltage side of urban and rural public transformers in China have the following disadvantages: First, they have single functions and are only used as line grids, which cannot improve power factor, improve voltage quality, and reduce line loss; The failure rate is high. The traditional knife-fuse isolating switch cannot open with load, and can only perform the opening and closing functions under no-load conditions, and its reliability is not high. , with the end of the transformation of urban and rural power grids, with the widespread application of integrated automation substations and the remote operation requirements for substations at the remote end of the centralized control center, it is urgent to improve the existing distribution boxes and design a A smart grid-type distribution transformer reactive power integrated box with powerful functions, high reliability and high degree of automation.

Utility model content

In view of this, the utility model provides a low-voltage distribution transformer reactive power compensation comprehensive box, which can be installed between the low-voltage side of the transformer and the low-voltage power grid instead of the low-voltage knife switch, and can be used as a short-circuit and overload protection device for the low-voltage power grid. It can stand underground and realize the input and cut-off operation of the low-voltage power grid by operating its "open" and "close". At the same time, it also has the function of reactive power compensation, and its performance is stable, safe and reliable.

The purpose of the utility model is to provide a low-voltage distribution transformer reactive power compensation comprehensive box, including a box body, and the box body includes a switch room and a capacitor room arranged side by side;

The switch chamber is provided with a metering and sampling current transformer, a knife melting switch, a compensation sampling current transformer and an integrated leakage protection switch device, and one end of the knife melting switch is electrically connected to the low-voltage terminal of the external transformer through the metering and sampling current transformer. The other end of the knife melting switch is electrically connected to the leakage comprehensive protection switch through the compensation sampling current transformer;

A capacitance compensation device and a metering terminal are arranged inside the capacitor chamber, the capacitance compensation device is connected between the compensation sampling current transformer and the integrated leakage protection switch device, and the metering terminal is connected to the output end of the metering sampling current transformer ;

The low-voltage distribution transformer reactive power compensation comprehensive box also includes a switching automatic control unit, and the switching automatic control unit is respectively connected with the metering sampling current transformer, the compensation sampling current transformer and the capacitance compensation device.

Further, the switching automatic control unit includes a microprocessor unit, the metering sampling current transformer and the compensation sampling current transformer are respectively connected to the input pins of the microprocessor unit, and the output pins of the microprocessor unit are The pin is connected with the capacitance compensation device;

Further, the capacitance compensation device includes a self-healing low-voltage power capacitor, a miniature circuit breaker and an AC contactor connected to the self-healing low-voltage power capacitor;

Further, the capacitance compensation device adopts a hybrid networking mode of three-phase co-complementation and phase-splitting compensation;

Further, the self-healing low-voltage power capacitor has a built-in temperature sensor, and the temperature sensor is electrically connected to the input pin of the microprocessor;

Further, a display device is provided on the side of the capacitor chamber, and the display device is electrically connected to the microprocessor;

Further, the outer surface of the switch chamber is provided with an operation hole for external operation of the operation shaft of the knife fuse switch;

Further, the switching automatic control unit also includes a communication module, which is used to realize cascade communication between multiple low-voltage distribution transformer reactive power compensation integrated boxes;

Further, the metering and sampling current transformers, knife melting switches, compensating sampling current transformers and integrated leakage protection switch devices are arranged and installed in the switch room according to the principle of upper incoming lines and lower outgoing lines.

Further, the capacitor chamber adopts a side-opening door design.

The beneficial effects of the utility model are:

1. The utility model overcomes the disadvantages of the existing ordinary distribution box. In addition to being installed between the low-voltage side of the transformer and the low-voltage power grid instead of the low-voltage knife switch, as a short-circuit and overload protection device for the low-voltage power grid, the staff can also pass Operate its "open" and "close" to realize the input and cut-off operation of the low-voltage power grid, which reduces the various workloads of the staff and avoids stopping the high-voltage side of the transformer due to low-voltage faults. At the same time, it adopts a comprehensive leakage protection switch device. It integrates protections such as overload and short circuit, phase loss and undervoltage, residual current (leakage), zero line disconnection at the power supply terminal and automatic reclosing, which can greatly protect the personal safety of operators and enhance the safety and stability of the whole system ;

2. The utility model integrates the reactive power compensation function at the same time, fully absorbs the technical characteristics of three-phase common compensation and three-phase separate compensation, and can also realize the separate detection and detection of three-phase alternating current on the basis of traditional three-phase common compensation. Compensation, avoiding the "virtual compensation" situation of three-phase co-complementation, and improving the power factor of each phase of alternating current;

3. The utility model has the advantages of reliable performance, low cost, and obvious energy-saving effect. It can be used in various workplaces such as low-voltage power distribution areas and substations. The modular reactive power compensation device and leakage switch load test record The meter and the meter are placed together to reduce the number of distribution boxes on the pole, which has a significant effect on the technical transformation of the low-voltage power grid, reduces line loss, increases capacity and improves work efficiency, and has a good application prospect;

4. The capacitor room of the utility model adopts a side-opening door design, which is convenient for maintenance and replacement of components, and is also conducive to the dustproof and waterproof of the equipment.

Other advantages, objects, and features of the present invention will be set forth in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the investigation and research below, or Can get teaching from the practice of the present utility model. The objectives and other advantages of the utility model can be realized and obtained by the following description and claims.

Description of drawings

In order to make the purpose, technical solutions and advantages of the present utility model clearer, the utility model will be further described in detail below in conjunction with the accompanying drawings, wherein:

Fig. 1 is the external structure schematic diagram of the present utility model;

Fig. 2 is a schematic diagram of the internal structure of the utility model;

Fig. 3 is the top view of the utility model;

Fig. 4 is the equipment connection schematic diagram of the present utility model;

Fig. 5 is the control connection schematic diagram of the present utility model;

Fig. 6 is a schematic diagram of a single connection of the utility model adopting a three-phase switching mode;

Fig. 7 is a schematic diagram of multiple connection of the utility model adopting the three-phase switching mode.

Detailed ways

Preferred embodiments of the present utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the preferred embodiments are only for illustrating the utility model, rather than limiting the protection scope of the utility model.

As shown in Figures 1 to 4, the low-voltage distribution transformer reactive power compensation comprehensive box of the present utility model includes a box body, and the box body includes a switch room 1 and a capacitor room 2 arranged side by side;

The switch room 1 is equipped with a metering and sampling current transformer 11, a knife melting switch 12, a compensating sampling current transformer 13 and an integrated leakage protection switch device 14. One end of the knife melting switch 12 is connected to the low-voltage connection of the external transformer through the metering and sampling current transformer 11. The terminals are electrically connected, and the other end of the knife melting switch 12 is electrically connected to the integrated leakage protection switch device 14 through the compensation sampling current transformer 13, and is output to each electric load through the integrated leakage protection switch device 14; wherein, the metering and sampling current transformer 11 , knife melting switch 12, compensation sampling current transformer 13 and leakage comprehensive protection switch device 14 are arranged and installed in the switch room 1 according to the upper incoming line and the lower part outgoing line, and the outer surface of the switching room 1 is provided with a knife melting switch. Operation hole for external operation of the operation shaft.

Leakage comprehensive protection switch device 14 integrates protections such as overload and short circuit, phase loss and undervoltage, residual current (leakage), zero wire disconnection at the power supply end, and automatic reclosing. After the completion of the modular program, it can automatically display the real-time residual current value, the phase sequence of the fault leakage trip, and the remaining current value at the time of tripping, and can automatically track the residual current of the line, automatically increase or decrease the action value gear, and has manual and automatic points. Closing function, free conversion. The application of this device can greatly protect the personal safety of the operator, and enhance the safety and stability of the whole system.

Capacitance compensation device 21 and metering terminal 22 are arranged inside capacitor room 2, the input end of capacitance compensation device 21 is connected between compensation sampling current transformer 13 and leakage comprehensive protection switch device 14, the input end of metering terminal 22 is connected with metering sampling current The output ends of the transformers 11 are connected; the capacitance compensation device 21 includes a self-healing low-voltage power capacitor 211 , a miniature circuit breaker and an AC contactor connected with the self-healing low-voltage power capacitor 211 . The capacitor room of the utility model adopts a side-opening door design, which is convenient for maintenance and replacement of components, and is also beneficial to the dustproof and waterproof of the equipment.

As shown in Figure 5, the low-voltage distribution transformer reactive power compensation integrated box also includes a switching automatic control unit, which includes a microprocessor unit 3, and the input pins of the microprocessor unit 3 are respectively connected to the metering and sampling current transformers. 11. The compensation sampling current transformer 13 is connected to the voltage transformer 5 arranged on the external input bus, and the output pin of the microprocessor unit 3 is connected to the capacitance compensation device 21 .

A temperature sensor 6 is built in the self-healing low-voltage power capacitor, and the temperature sensor 6 is electrically connected to the input pin of the microprocessor 3 .

When the utility model is in use, the voltage on the three-phase incoming line bus is collected by the voltage transformer 5; the current flowing through the power line is collected by the external current transformer and input to the microprocessor 3 through the terminal; the temperature sensor 6 is used to collect temperature of the capacitor. The various data collected are quickly calculated by the micro-processing chip, and the zero-crossing switching is automatically realized by precise phase angle control.

In addition, the capacitor compensation device adopts a mixed network mode of three-phase co-complementation and phase-splitting compensation. Three-phase co-complement and phase-separate compensation are jointly networked, which can effectively control the three-phase balance of the system, greatly improve the system compensation efficiency, precisely control the system power factor, and avoid the problems of over-compensation, under-compensation and three-phase imbalance in the system.

A display device is provided on the side of the capacitor chamber 2, and the display device is electrically connected to the microprocessor. In this embodiment, an input keyboard can also be configured to realize man-machine communication on the spot.

The switching automatic control unit also includes a communication module, which is used to realize cascade communication and grid-connected operation among multiple low-voltage distribution transformer reactive power compensation integrated boxes.

As shown in Figure 6 and Figure 7, the utility model can be used alone or in combination. Through the communication module (RS485 interface mode is used in this embodiment), it can be connected to the background computer for comprehensive management of power distribution. When the capacitors are used in a network, the electrical isolation cascading method and the photoelectric isolation RS485 communication method are used to form a star network of multiple capacitors in a master-slave manner. One of the capacitor controllers is the master and the other is the slave.

The utility model also has the function of dynamic compensation. The main machine directly controls the switching state of each slave machine according to the power factor, etc., and records it, and performs automatic switching according to the required capacity to form a low-voltage reactive power automatic control system; if individual slave machines Failure, automatic exit, does not affect the rest of the work; if the master fails, it will automatically exit, and a new master will be generated among the remaining slaves to form a new system. Switch according to the principle of supplement.

In a word, the above embodiments are only used to illustrate the technical solution of the utility model without limitation, although the utility model has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solution of the utility model can be carried out Modifications or equivalent replacements, without departing from the spirit and scope of the technical solution, should be covered by the claims of the present utility model.

Claims (10)

1. The low-voltage distribution transformer reactive power compensation comprehensive box, including the box body, is characterized in that: the box body includes a switch room and a capacitor room arranged side by side; The switch chamber is provided with a metering and sampling current transformer, a knife melting switch, a compensation sampling current transformer and an integrated leakage protection switch device, and one end of the knife melting switch is electrically connected to the low-voltage terminal of the external transformer through the metering and sampling current transformer. The other end of the knife melting switch is electrically connected to the leakage comprehensive protection switch through the compensation sampling current transformer; A capacitance compensation device and a metering terminal are arranged inside the capacitor chamber, the capacitance compensation device is connected between the compensation sampling current transformer and the integrated leakage protection switch device, and the metering terminal is connected to the output end of the metering sampling current transformer ; The low-voltage distribution transformer reactive power compensation comprehensive box also includes a switching automatic control unit, and the switching automatic control unit is respectively connected with the metering sampling current transformer, the compensation sampling current transformer and the capacitance compensation device. 2. The integrated reactive power compensation box for low-voltage distribution transformers according to claim 1, characterized in that: the switching automatic control unit includes a microprocessor unit, and the metering and sampling current transformers and compensation sampling current transformers are respectively connected to The input pins of the microprocessor unit are connected, and the output pins of the microprocessor unit are connected with the capacitance compensation device. 3. The low-voltage distribution transformer reactive power compensation comprehensive box as claimed in claim 2, characterized in that: the capacitance compensation device includes a self-healing low-voltage power capacitor, a miniature circuit breaker connected to the self-healing low-voltage power capacitor and AC contactor. 4. The integrated reactive power compensation box for low-voltage distribution transformers according to claim 3, characterized in that: said capacitor compensation device adopts a hybrid networking mode of three-phase co-compensation and phase-separated compensation. 5. The integrated reactive power compensation box for low-voltage distribution transformers according to claim 4, wherein a temperature sensor is built in the self-healing low-voltage power capacitor, and the temperature sensor is electrically connected to the input pin of the microprocessor. 6. The integrated reactive power compensation box for low-voltage distribution transformers according to claim 5, wherein a display device is provided on the side of the capacitor chamber, and the display device is electrically connected to the microprocessor unit. 7. The integrated reactive power compensation box of low-voltage distribution transformer according to claim 6, characterized in that: the outer surface of the switch chamber is provided with an operation hole for external operation of the operation shaft of the knife fuse switch. 8. The low-voltage distribution transformer reactive power compensation integrated box according to claim 7, characterized in that: the switching automatic control unit also includes a cascade communication device for realizing multiple low-voltage distribution transformer reactive power compensation integrated boxes communication module. 9. The low-voltage distribution transformer reactive power compensation comprehensive box according to any one of claims 1 to 8, characterized in that: the metering and sampling current transformer, knife fuse switch, compensation sampling current transformer and leakage integrated The protective switch devices are arranged and installed in the switch room according to the principle of upper incoming line and lower outgoing line. 10. The integrated reactive power compensation box for low-voltage distribution transformers according to claim 9, wherein the capacitor chamber adopts a side-opening door design.

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