Voltage stabilizer for low-voltage line

Abstract

The utility model discloses a voltage stabilizing device for a low-voltage line, which relates to the technical field of power grid voltage balancing equipment and comprises a lower shell and an upper shell, the upper shell is fixedly mounted at the top of the lower shell, a plurality of groups of capacitors are fixedly arranged in the lower shell, a plurality of groups of switches are fixedly arranged in the upper shell, the plurality of groups of switches correspond to the plurality of groups of capacitors, and the plurality of groups of switches correspond to the plurality of groups of capacitors. The group of switches and the group of capacitors are connected in series, a controller is fixedly arranged in the upper shell and is electrically connected with the plurality of groups of switches, a voltage measuring element and a current measuring element are fixedly arranged in the upper shell and are electrically connected with the controller, a wiring part is fixedly arranged at one end of the outer part of the upper shell, and the wiring part is electrically connected with the controller. The wiring part is electrically connected with the power grid, and a touch screen is fixedly arranged on one side of the outer portion of the upper shell and electrically connected with the controller. According to the utility model, the voltage drop at the tail end of the low-voltage line can be improved, the power factor is improved, and the tail-end voltage of the low-voltage line is balanced and supported.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of power grid voltage balancing equipment, especially to a voltage stabilizing device for low voltage line. BACKGROUND

[0002] In the stage of rapid development of China's social economy in recent years, the material living standards of residents in urban and rural areas are continuously improved, household appliances are increasingly rich, and the power consumption in rural areas is also rising; many urban and rural areas are full of small and micro processing enterprises and breeding bases, and the power consumption increases greatly. Due to the wide area of rural areas and the scattered population distribution, the early construction of power grid frame line is simple and weak, the load dispersion degree is high, the seasonality and time period characteristics are obvious, which leads to the increasingly serious problems of low voltage at the end of the line and three-phase imbalance.

[0003] At present, the methods to solve the problem of low voltage at the end of the line include increasing voltage regulators in medium or low voltage lines, increasing reactive power compensation equipment in lines or stations, etc. The medium voltage line voltage regulation adjusts the autotransformer through the tap changer to achieve the purpose of regulating the line voltage of the station transformer, and the 10kV line compensation also achieves the purpose of improving the line voltage by compensating the reactive load of the line. These two types of equipment will simultaneously increase the outlet voltage of the regulated station area, and the covered area is wide, and the voltage regulation effect is obvious; however, in the case of serious three-phase load imbalance in the station area, it may cause the voltage of some or two phases of the low voltage line to be seriously high, which poses a risk to the safe use of equipment. The low voltage station reactive power compensation is installed at the outlet side of the distribution transformer, and cannot balance the reactive load of the load in place, which aggravates the problem of low voltage at the end of the line caused by line voltage drop, and cannot balance the three-phase load. Then, the low voltage line voltage regulator is installed in the middle and rear sections of the line, which is a series device that can improve the voltage at the rear end of the equipment installation point, but when the load at the rear end increases, it will cause the voltage at the front end of the installation point to decrease, and also cannot handle the imbalance and reactive power problems of the load at the installation point. Finally, these devices have the defects of heavy weight, inconvenient installation and high cost. Therefore, a technical scheme for improving the voltage drop of the line and balancing the voltage at the end is needed. UTILITY MODEL CONTENTS

[0004] The utility model aims at solving the above problems and provides a voltage stabilizing device for low voltage line.

[0005] The utility model realizes the above-mentioned purposes through the following technical schemes:

[0006] A kind of voltage stabilizing device for low-voltage line, including lower shell and upper shell, the upper shell is fixedly installed on the top of the lower shell, a plurality of groups of capacitors are fixedly arranged in the lower shell, a plurality of groups of switches are fixedly arranged in the upper shell, a plurality of groups of the switch correspond to a plurality of groups of the capacitor, a group of the switch is in series with a group of the capacitor, controller is fixedly arranged in the upper shell, the controller is electrically connected with a plurality of groups of the switch respectively, voltage measuring element and current measuring element are fixedly arranged in the upper shell, the voltage measuring element and the current measuring element are electrically connected with the controller, wiring part is fixedly arranged at one end outside the upper shell, the wiring part is electrically connected with power grid, touch screen is fixedly arranged on one side outside the upper shell, the touch screen is electrically connected with the controller.

[0007] Preferably, the number of capacitors is 2-6 groups.

[0008] Preferably, the capacitances of the plurality of groups of capacitors are not the same.

[0009] Preferably, the lower shell and the upper shell are made of stainless steel material.

[0010] Preferably, the inner side wall and the bottom of the lower shell are fixedly provided with an insulating layer.

[0011] Preferably, the lower shell is filled with an insulating medium between the insulating layer and the plurality of groups of capacitors.

[0012] Preferably, the insulating medium is in solid state.

[0013] Preferably, the plurality of groups of capacitors are connected in parallel on the power grid; the plurality of groups of capacitors are connected in parallel.

[0014] Preferably, the voltage measuring element is connected in parallel on the power grid; the current measuring element is connected in series on the power grid.

[0015] The beneficial effects of this utility model are as follows: (1) This utility model can improve the voltage drop at the end of the low-voltage line, improve the power factor, and balance and support the voltage at the end of the low-voltage line; (2) Multiple sets of capacitors form multiple independent single-phase capacitors. Each set of single-phase capacitors is connected to its corresponding switch to achieve single-phase reactive power balance and balance the voltage at the end of the low-voltage line. When the voltage of the power grid is lower than 197V, a set of single-phase capacitors is put into operation. If the voltage of the power grid is still too low, another set of single-phase capacitors is put into operation until multiple sets of single-phase capacitors are put into operation. When the voltage of the power grid is higher than 236V, the voltage of the power grid is balanced. When the voltage of the grid is still too high, disconnect one set of single-phase capacitors. If the voltage of the grid is still too high, disconnect another set of single-phase capacitors until multiple sets of single-phase capacitors are disconnected. The sampling response time is completed within 0.1ms and the switching is cyclically changed within 0.2ms through the controller. (3) The upper and lower shells are made of stainless steel, which has strong protection performance and can be directly installed outdoors. (4) The cost of the entire voltage stabilizing device is low, the overall weight is light, and the installation and maintenance are convenient. It is easy to flexibly select the installation point in combination with the load distribution of the grid. It can also be installed at multiple points to achieve a more ideal regulation effect. Attached Figure Description

[0016] Figure 1 This is a perspective view of the overall structure of this utility model;

[0017] Figure 2 This is a schematic diagram of the internal structure of the lower shell of this utility model;

[0018] Figure 3 This is a schematic diagram illustrating the working principle of this utility model.

[0019] Explanation of reference numerals in the attached figures:

[0020] 11. Lower housing; 111. Insulating layer; 112. Insulating medium; 12. Upper housing; 121. Wiring part; 122. Touch screen; 21. First capacitor; 22. Second capacitor; 23. Third capacitor; 24. Fourth capacitor; 3. Controller; 4. Voltage measuring element; 5. Current measuring element; 61. First switch; 62. Second switch; 63. Third switch; 64. Fourth switch. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings:

[0022] like Figure 1 , Figure 2 and Figure 3As shown, this utility model provides a voltage stabilizing device for low-voltage lines, including a lower housing 11 and an upper housing 12. The upper housing 12 is fixedly mounted on the top of the lower housing 11 by screws. Multiple sets of capacitors are fixedly installed inside the lower housing 11, and multiple sets of switches are fixedly installed inside the upper housing 12. Each set of switches corresponds to a set of capacitors, and each set of switches is connected in series with a set of capacitors via a wire. A controller 3, which can be a microcontroller, is fixedly mounted inside the upper housing 12 by screws. The controller 3 is connected to the multiple sets of switches via signal lines, and the switches can be phase-selective switches. A voltage measuring element 4 and a current measuring element 5 are fixedly installed inside the upper housing 12. Both the voltage measuring element 4 and the current measuring element 5 are connected to the controller 3 via signal lines. For example, the voltage measuring element 4 can be a voltage transformer, and the current measuring element 5 can be a current transformer. A wiring section 112 is fixedly installed at one end of the upper housing 12, and the wiring section 112 is connected to the power grid via a wire. A touch screen 122 is fixedly installed on one side of the upper housing 12, and the touch screen 122 is connected to the controller 3 via a signal line. In this device, multiple sets of capacitors are connected in parallel to the power grid; multiple sets of capacitors are connected in parallel with each other; voltage measuring element 4 is connected in parallel to the power grid; and current measuring element 5 is connected in series to the power grid. This voltage stabilizing device can improve the voltage drop at the end of low-voltage lines, increase the power factor, and balance and support the voltage at the end of low-voltage lines.

[0023] like Figure 2 and Figure 3 As shown, the number of capacitors ranges from 2 to 6 groups, and the number of groups can be selected according to actual needs. In this embodiment, 4 groups of capacitors are used, namely, the first capacitor 21, the second capacitor 22, the third capacitor 23, and the fourth capacitor 24. Correspondingly, multiple sets of switches include the first switch 61, the second switch 62, the third switch 63, and the fourth switch 64. The capacitances of the multiple groups of capacitors are not the same. For example, in this embodiment, the capacitance of the first capacitor 21 is greater than that of the second capacitor 22, the capacitance of the second capacitor 22 is greater than that of the third capacitor 23, and the capacitance of the third capacitor 23 is greater than that of the fourth capacitor 24. The multiple groups of capacitors form multiple independent single-phase capacitors. Each group of single-phase capacitors is connected to its corresponding switch to achieve single-phase reactive power balance and balance the terminal voltage of the low-voltage line.

[0024] In this embodiment, both the lower housing 11 and the upper housing 12 are made of stainless steel. Stainless steel offers strong protection and can be installed directly outdoors.

[0025] like Figure 2 As shown, in this embodiment, an insulating layer 111 is fixedly provided on the inner sidewall and bottom of the lower housing 11. The insulating layer 111 can be made of mica sheet. An insulating medium 112 is filled between the insulating layer 111 and the multiple sets of capacitors inside the lower housing 11. The insulating medium 112 is solid and can be made of silicone.

[0026] like Figures 1 to 3 As shown, during operation, (1) First, the wiring part 112 of the voltage regulator is connected to the power grid via a wire to connect the voltage regulator to the power grid. Then, the voltage regulator is powered on and initialized, including hardware initialization and self-test. The voltage parameter range value is set through the touch screen 122, and the operating conditions of the voltage regulator are set. (2) The voltage value of the power grid is collected by the voltage measuring element 4, and the current value of the power grid is collected by the current measuring element 5. The voltage value and current value information are transmitted to the controller 3. The controller 3 calculates the active power and reactive power of the power grid. Then, the controller 3 calculates the voltage compensation requirement of the power grid (i.e., the end of the low-voltage line) according to the set voltage regulation parameters and controls the opening and closing of multiple sets of switches to perform voltage compensation. First, the gap that needs to be compensated for in this phase is calculated according to the power and current of the power grid. The compensation and cut-off are performed according to the actual gap. Specifically, when the grid voltage is below 197V, one set of single-phase capacitors is switched on. If the grid voltage remains low, another set of single-phase capacitors is switched on, and so on, until multiple sets of single-phase capacitors are switched on. When the grid voltage is above 236V, one set of single-phase capacitors is switched off. If the grid voltage remains high, another set of single-phase capacitors is switched off, and so on, until multiple sets of single-phase capacitors are switched off. This is automatically controlled by controller 3, ensuring that the sampling response time is completed within 0.1ms and the switching is rapidly cyclical within 0.2ms. The voltage regulator automatically tracks the grid voltage and the zero-potential points of the multiple capacitors to find the appropriate moment to act and complete the command execution response.

[0027] This invention solves the problem of low voltage at the end of low-voltage lines. The voltage stabilizing device has a low cost, light weight, and is easy to install and maintain. It allows for flexible selection of installation points based on the load distribution of the power grid, and can also be installed at multiple points to achieve a more ideal regulation effect.

[0028] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Those skilled in the art should understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of this utility model, and all such changes should be covered within the protection scope of this utility model. The protection scope of this utility model is defined by the claims and their equivalents.

Claims

1. A voltage stabilizing device for low-voltage lines, characterized in that: The device includes a lower housing and an upper housing. The upper housing is fixedly mounted on top of the lower housing. Multiple sets of capacitors are fixedly installed inside the lower housing. Multiple sets of switches are fixedly installed inside the upper housing, with each set of switches corresponding to a set of capacitors. Each set of switches is connected in series with a set of capacitors. A controller is fixedly installed inside the upper housing and is electrically connected to each set of switches. A voltage measuring element and a current measuring element are fixedly installed inside the upper housing and are electrically connected to the controller. A wiring section is fixedly installed at one end of the upper housing and is electrically connected to the power grid. A touch screen is fixedly installed on one side of the upper housing and is electrically connected to the controller.

2. The voltage stabilizing device for low-voltage lines according to claim 1, characterized in that: The number of capacitors is 2 to 6 groups.

3. A voltage stabilizing device for low-voltage lines according to claim 1, characterized in that: The capacitance values ​​of the multiple sets of capacitors are not the same.

4. A voltage stabilizing device for low-voltage lines according to claim 1, characterized in that: Both the lower housing and the upper housing are made of stainless steel.

5. A voltage stabilizing device for low-voltage lines according to claim 1, characterized in that: The inner wall and bottom of the lower housing are both fixedly provided with an insulating layer.

6. A voltage stabilizing device for low-voltage lines according to claim 5, characterized in that: The lower housing is filled with an insulating medium between the insulating layer and the multiple sets of capacitors.

7. A voltage stabilizing device for low-voltage lines according to claim 6, characterized in that: The insulating medium is solid.

8. A voltage stabilizing device for low-voltage lines according to claim 1, characterized in that: Multiple sets of the capacitors are connected in parallel to the power grid; multiple sets of the capacitors are connected in parallel with each other.

9. A voltage stabilizing device for low-voltage lines according to claim 1, characterized in that: The voltage measuring element is connected in parallel to the power grid; the current measuring element is connected in series to the power grid.

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