Low-voltage distribution line compensation type voltage stabilizing device

Abstract

The utility model provides a compensation type voltage stabilizing device for a low-voltage distribution line. The compensation type voltage stabilizing device comprises a controller, a switch module, a voltage regulating transformer, a compensation type transformer and a current mutual inductance module, the output end of the controller is connected to the initial end of the primary side of the regulating transformer; a voltage regulating tap of the voltage regulating transformer and the switch module are connected to the initial end of the primary side of the compensation transformer; the secondary side of the compensation transformer is connected in series in the low-voltage distribution line; a bypass contactor is also connected between the voltage regulating tap of the voltage regulating transformer and the secondary side of the compensation transformer; the controller is arranged between a zero line and a live line of the low-voltage distribution line; the two current mutual inductance modules are arranged on a live wire of the low-voltage distribution line, and one end of the first current mutual inductance module is further connected with a voltage regulating tap of the voltage regulating transformer; one end of the second current mutual inductance module is also connected with the secondary side of the compensation transformer; and the two current mutual inductance modules are also connected to the input end of the controller. The device can effectively guarantee the power supply quality, and improves the voltage qualified rate.

Description

Technical Field

[0001] The utility model belongs to the technical field of low - voltage distribution in power systems, and the device relates to a compensation - type voltage stabilizing device for low - voltage distribution lines. Background Technique

[0002] With the rapid development of society, the scale of the low - voltage power distribution system is constantly expanding. The low voltage of the low - voltage power distribution system makes it inconvenient for users to use electricity. Therefore, it is necessary to transform and upgrade the low - voltage power distribution system to improve the problem of low voltage in the low - voltage power distribution system. With the increasing requirements for voltage quality, especially the popularization of smart meters, the problem of voltage quality has emerged, and a large number of low - voltage problems have occurred. How to effectively manage the low voltage in the low - voltage distribution network is an important part of daily operation and planning work. The problem of low power quality caused by low voltage has attracted the attention of both power users and suppliers. Grid enterprises have also carried out a large number of management and prevention work on the low - voltage problem of the distribution network, but the low - voltage problem has not been effectively solved.

[0003] In the prior art, relevant low - voltage compensation methods have been disclosed. For example, in the Chinese patent application number: 202311515007.2, titled: A distributed low - voltage fine compensation system and its compensation method, voltage compensation is carried out using the power factor, and the optimal target power factor is automatically determined according to the number of compensation capacitors. However, in the process of method execution, the process of determining the compensation combination is relatively complex, there are errors in the determination of the target power factor, and the patent does not disclose the ability to stably improve the voltage at the end of the low - voltage distribution line. Therefore, it is very necessary to propose a hardware device to solve the problem of low voltage in long - distance power supply of the low - voltage distribution system. Summary of the Invention

[0004] In order to solve the above - mentioned technical problems, the utility model proposes a compensation - type voltage stabilizing device for low - voltage distribution lines, which can stably improve the voltage at the end of the low - voltage distribution line and ensure normal power supply for users.

[0005] To achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A compensation - type voltage stabilizing device for low - voltage distribution lines includes a controller, a switch module, a voltage regulating transformer, a compensation transformer, a first current mutual - inductance module, and a second current mutual - inductance module;

[0007] The output end of the controller is connected to the start end of the primary side of the voltage regulating transformer; the voltage regulating tap of the voltage regulating transformer and the switch module are both connected to the start end of the primary side of the compensation transformer; the secondary side of the compensation transformer is connected in series in the low - voltage distribution line; a bypass contactor is also connected between the voltage regulating tap of the voltage regulating transformer and the secondary side of the compensation transformer; the controller is arranged between the neutral line and the live line of the low - voltage distribution line;

[0008] The first current mutual inductance module is arranged on the live wire of the low-voltage distribution line, and one end of the first current mutual inductance module is also connected to the voltage regulating tap of the voltage regulating transformer; the first current mutual inductance module is also connected to the input end of the controller.

[0009] The second current mutual inductance module is arranged on the live wire of the low-voltage distribution line, and one end of the second current mutual inductance module is also connected to the secondary side of the compensation transformer; the second current mutual inductance module is also connected to the input end of the controller.

[0010] Further, the device further includes a capacitor module;

[0011] The capacitor module is connected in series between the neutral wire and the live wire of the low-voltage distribution line, and the capacitor module is connected to the controller.

[0012] Further, the capacitor module includes a first capacitor, a second capacitor and a third capacitor; the first capacitor and the fifth switch form a first loop; the second capacitor and the sixth switch are connected in series to form a second loop, and the third capacitor and the seventh switch are connected in series to form a third loop; the first loop, the second loop and the third loop are connected in parallel to form a capacitor loop;

[0013] Further, the capacitor loop is arranged between the neutral wire and the live wire of the low-voltage distribution line after being connected to the capacitor branch switch.

[0014] Further, the device further includes a first lightning arrester and a second lightning arrester; one end of the first lightning arrester is connected to the live wire of the low-voltage distribution line, and the other end is grounded; one end of the second lightning arrester is connected to the live wire of the low-voltage distribution line, and the other end is grounded.

[0015] Further, the switch module includes a first switch, a second switch, a third switch and a fourth switch connected in parallel;

[0016] The contacts of the first switch, the contacts of the second switch, the contacts of the third switch and the contacts of the fourth switch are all connected to the voltage regulating transformer; the coils of the first switch, the coils of the second switch, the coils of the third switch and the coils of the fourth switch are all connected to the controller.

[0017] Further, an air circuit breaker is arranged between the voltage regulating tap of the voltage regulating transformer and the secondary side of the compensation transformer.

[0018] Further, the normally open contact of the bypass contactor is connected between the voltage regulating tap of the voltage regulating transformer and the live wire.

[0019] Further, the normally open contact of the bypass contactor is connected to the secondary side of the compensation transformer through the normally closed contact of the bypass contactor.

[0020] The effects provided in the invention content are only the effects of the embodiments, rather than all the effects of the invention. One embodiment of the above technical solution has the following advantages or beneficial effects:

[0021] The utility model provides a compensated voltage stabilizing device for low-voltage distribution lines, which includes a controller, a switch module, a voltage regulating transformer, a compensated transformer, a first current mutual induction module and a second current mutual induction module; the output end of the controller is connected to the starting end of the primary side of the voltage regulating transformer; the voltage regulating tap of the voltage regulating transformer and the switch module are both connected to the starting end of the primary side of the compensated transformer; the secondary side of the compensated transformer is connected in series in the low-voltage distribution line; a bypass contactor is also connected between the voltage regulating tap of the voltage regulating transformer and the secondary side of the compensated transformer; the controller is arranged between the neutral wire and the live wire of the low-voltage distribution line; the first current mutual induction module is arranged on the live wire of the low-voltage distribution line, and one end of the first current mutual induction module is also connected to the voltage regulating tap of the voltage regulating transformer; the first current mutual induction module is also connected to the input end of the controller. The second current mutual induction module is arranged on the live wire of the low-voltage distribution line, and one end of the second current mutual induction module is also connected to the secondary side of the compensated transformer; the second current mutual induction module is also connected to the input end of the controller. The utility model can effectively guarantee the power supply quality, improve the voltage qualification rate, and does not generate harmonics during the operation process, providing a safe, reliable, economic and convenient comprehensive treatment solution for the distribution lines with unstable power supply quality and low voltage, saving a large amount of manpower and material resources for the power grid company and providing a stable and reliable power consumption experience for power users.

[0022] The utility model can solve the low-voltage problem of the low-voltage distribution system. Through the treatment and transformation of the low-voltage problem of the low-voltage distribution system, the equipment level of the low-voltage distribution system in China can be improved, the voltage magnitude at the end of the line can be ensured to meet the actual needs of users, and while reducing the labor intensity of the staff, the stable operation of the power system can be ensured. Brief Description of the Drawings

[0023] Figure 1 It is a connection schematic diagram of a compensated voltage stabilizing device for low-voltage distribution lines proposed in Embodiment 1 of the utility model;

[0024] Figure 2 It is a schematic diagram of the boosting regulation principle of the compensated voltage stabilizing device for low-voltage distribution lines proposed in Embodiment 1 of the utility model. Detailed Description of the Invention

[0025] To clearly illustrate the technical features of this solution, the following will elaborate on this utility model in detail through specific embodiments and in conjunction with its attached drawings. The following disclosure provides many different embodiments or examples for implementing different structures of this utility model. To simplify the disclosure of this utility model, components and settings of specific examples are described below. In addition, this utility model may repeat reference numerals and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between various embodiments and / or settings discussed. It should be noted that the components illustrated in the drawings are not necessarily drawn to scale. This utility model omits the description of well-known components, processing technologies, and processes to avoid unnecessarily limiting this utility model.

[0026] Embodiment 1

[0027] Embodiment 1 of this utility model proposes a compensated voltage stabilizing device for low-voltage distribution lines, which is used to solve the problem of low voltage in low-voltage distribution systems.

[0028] Figure 1 A compensated voltage stabilizing device for low-voltage distribution lines proposed in Embodiment 1 of this utility model includes a controller, a switch module, a voltage regulating transformer, a compensated transformer, a first current mutual inductance module, and a second current mutual inductance module;

[0029] The output end of the controller is connected to the primary start end of the voltage regulating transformer; the voltage regulating tap of the voltage regulating transformer and the switch module are both connected to the primary start end of the compensated transformer; the secondary side of the compensated transformer is connected in series in the low-voltage distribution line; a bypass contactor is also connected between the voltage regulating tap of the voltage regulating transformer and the secondary side of the compensated transformer; the controller is arranged between the neutral line and the live wire of the low-voltage distribution line;

[0030] The first current mutual inductance module TA1 is arranged on the live wire of the low-voltage distribution line, and one end of the first current mutual inductance module TA1 is also connected to the voltage regulating tap of the voltage regulating transformer TB2; the first current mutual inductance module TA1 is also connected to the input end of the controller TK1.

[0031] The second current mutual inductance module TA2 is arranged on the live wire of the low-voltage distribution line, and one end of the second current mutual inductance module TA is also connected to the secondary side of the compensated transformer TB2; the second current mutual inductance module TA2 is also connected to the input end of the controller.

[0032] In Figure 1 it includes: controller TK1, current transformers TA1 and TA2, compensated transformer TB1, voltage regulating transformer TB2, bypass contactor KM1.

[0033] The secondary side of the compensation transformer TB1 is connected in series to the distribution line. The starting end of the primary side is interconnected with the voltage regulating taps of the voltage regulating transformer TB2 and the synchronous zero-crossing voltage regulating switches K1 to K4, and the ending end is connected to the ending end of the voltage regulating transformer TB2 and then connected to the neutral line together.

[0034] The switch module includes the first switch K1, the second switch K2, the third switch K3, and the fourth switch K4 connected in parallel; the contacts of the first switch K1, the second switch K2, the third switch K3, and the fourth switch K4 are all connected to the voltage regulating transformer; the coils of the first switch K1, the second switch K2, the third switch K3, and the fourth switch K4 are all connected to the controller.

[0035] The device also includes a first lightning arrester FV1 and a second lightning arrester FV2; one end of the first lightning arrester FV1 is connected to the live wire of the low-voltage distribution line, and the other end is grounded; one end of the second lightning arrester FV2 is connected to the live wire of the low-voltage distribution line, and the other end is grounded.

[0036] The device also includes a capacitor module; the capacitor module is connected in series between the neutral line and the live wire of the low-voltage distribution line, and the capacitor module is connected to the controller.

[0037] The capacitor module includes a first capacitor C1, a second capacitor C2, and a third capacitor C3; the first capacitor C1 and the fifth switch K5 form a first loop; the second capacitor C2 and the sixth switch K6 are connected in series to form a second loop, and the third capacitor C3 and the seventh switch K7 are connected in series to form a third loop; the first loop, the second loop, and the third loop are connected in parallel to form a capacitor loop;

[0038] The capacitor loop is connected to the capacitor branch switch QF2 and then arranged between the neutral line and the live wire of the low-voltage distribution line.

[0039] The precision compensation capacitors C1 to C3 also have the function of automatic zero-crossing switching, can detect the reactive power demand of the installation point line by themselves, realize automatic tracking and compensation of the reactive power at the access point, ensure that the reactive current flowing through the secondary winding of the compensation transformer is reduced to the lowest level, and at the same time stably improve the reactive voltage of the line.

[0040] An air circuit breaker is also arranged between the voltage regulating tap of the voltage regulating transformer and the secondary side of the compensation transformer.

[0041] The normally open contact QF1 of the bypass contactor is connected between the voltage regulating tap of the voltage regulating transformer and the live wire.

[0042] The normally open contact of the bypass contactor is connected to the secondary side of the compensation transformer through the normally closed contact of the bypass contactor.

[0043] Figure 2Schematic diagram of the boost regulation principle of the compensated voltage stabilizer for low-voltage distribution lines proposed in Embodiment 1 of the present utility model. The operation control of the device includes: when the voltage regulation operation condition is met, the controller TK1 can control one of the synchronous zero-crossing voltage regulation switches K1-K4 to close, adjust the primary voltage of the compensation transformer TB1, change its output voltage ΔU. When ΔU is in the same frequency and phase as the line voltage, Uo = Ui + ΔU; when ΔU is in the same frequency but opposite phase as the line voltage, Uo = Ui - ΔU, thus realizing the boost or buck regulation of the output voltage Uo.

[0044] In the figure, the input current Ii of the low-voltage distribution line compensated voltage stabilizer is equal to the sum of the output current Io and the voltage regulation current I2, that is, Ii = Io + I2. The compensation current I3 flowing through the compensation transformer is equal to the sum of the voltage regulation current I2 and the autotransformer current I4, that is, I3 = I2 + I4. Let the turns ratio of the compensation transformer TB1 be equal to n. In the maximum state, its primary current I3 = Io / n. Usually, the turns ratio of the compensation transformer is designed to be about 5:1. Therefore, the current I3 flowing through the primary winding of the compensation transformer is only about 1 / 5 of the device output current Io. So, the operating current of the synchronous zero-crossing voltage regulation switches K1-K4 is greatly reduced, and a very good control effect can be achieved.

[0045] When the controller TK1 monitors that the input voltage Ui is qualified (≥198V, the maximum can be set to 220V), it issues a bypass operation command. The bypass contactor KM1 disconnects, its normally closed point closes, and its normally open point disconnects. The device operates in the bypass operation mode to reduce the loss of the compensation transformer, improve the device efficiency and service life.

[0046] When the controller TK1 monitors that the input voltage Ui is unqualified (<198V, the maximum can be set to 220V), it issues a voltage regulation operation command. The contactor KM1 is energized, its normally open point closes, and its normally closed point disconnects. The device operates in the automatic voltage regulation operation mode to boost the output voltage Uo to the qualified range.

[0047] The voltage regulation transformer TB2 has 6 taps, which are connected to the start end of the primary winding of the compensation transformer through 4 synchronous switching switches (the taps can be adjusted according to the on-site situation). The controller TK1 adjusts to the appropriate gear according to the device input voltage Ui and output voltage Uo to make the output voltage Uo within the qualified range.

[0048] When the device is abnormal or the operating current reaches the rated value of the device, the controller automatically issues a bypass command to make the device exit the voltage regulation operation mode, ensuring the safe operation of the device and continuous power supply. For this reason, the rated current of the bypass contactor is selected according to 1.5 times the line rated current.

[0049] When the input voltage is qualified, the contactor KM1 automatically enters the bypass operation, and the current does not pass through the compensation winding, without generating power loss.

[0050] The device can operate automatically and normally in the bypass state, accurately and finely compensate for the reactive power of the line, and reduce the reactive power loss and reactive voltage drop.

[0051] A compensated voltage stabilizing device for low-voltage distribution lines proposed in Embodiment 1 of the present utility model has automatic multi-stage gear boost control, and can change the tap to adjust the voltage boost rate by 7%, 12%, 15%, 18%, 20%, and 24%.

[0052] A compensated voltage stabilizing device for low-voltage distribution lines proposed in Embodiment 1 of the present utility model has protection and alarm functions such as overvoltage, undervoltage, first-stage overcurrent, second-stage overcurrent, over-temperature, harmonics, and regulating switch failure.

[0053] A compensated voltage stabilizing device for low-voltage distribution lines proposed in Embodiment 1 of the present utility model can solve the low-voltage problem of the low-voltage power distribution system. Through the treatment and transformation of the low-voltage problem of the low-voltage power distribution system, the equipment level of the low-voltage power distribution system in China can be improved, the voltage magnitude at the end of the line can be ensured to meet the actual needs of users, and while reducing the labor intensity of the staff, the stable operation of the power system can be ensured.

[0054] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes the inherent elements thereof. Without further limitation, the element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element. In addition, the parts of the above technical solutions provided in the embodiments of the present application that are consistent with the corresponding technical solutions in the prior art in terms of implementation principles are not described in detail to avoid excessive elaboration.

[0055] Although the specific implementation manners of the present utility model are described above in conjunction with the accompanying drawings, they do not limit the protection scope of the present utility model. For those skilled in the art, other different forms of modification or variation can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Based on the technical solutions of the present utility model, various modifications or variations that can be made by those skilled in the art without creative labor are still within the protection scope of the present utility model.

Claims

1. A compensated voltage stabilization device for low-voltage distribution lines, characterized in that, It includes a controller, a switch module, a voltage regulating transformer, a compensating transformer, a first current mutual inductance module, and a second current mutual inductance module; The output terminal of the controller is connected to the starting end of the primary side of the voltage regulating transformer; the voltage regulating tap of the voltage regulating transformer and the switch module are both connected to the starting end of the primary side of the compensating transformer; the secondary side of the compensating transformer is connected in series in the low-voltage distribution line; a bypass contactor is also connected between the voltage regulating tap of the voltage regulating transformer and the secondary side of the compensating transformer; the controller is arranged between the neutral line and the live wire of the low-voltage distribution line; The first current mutual inductance module is arranged on the live wire of the low-voltage distribution line, and one end of the first current mutual inductance module is also connected to the voltage regulating tap of the voltage regulating transformer; the first current mutual inductance module is also connected to the input terminal of the controller; The second current mutual inductance module is arranged on the live wire of the low-voltage distribution line, and one end of the second current mutual inductance module is also connected to the secondary side of the compensating transformer; the second current mutual inductance module is also connected to the input terminal of the controller.

2. The compensated voltage stabilizing device for low-voltage distribution lines according to claim 1, characterized in that, The device also includes a capacitor module; The capacitor module is connected in series between the neutral line and the live wire of the low-voltage distribution line, and the capacitor module is connected to the controller.

3. The compensated voltage stabilizing device for low-voltage distribution lines according to claim 2, characterized in that, The capacitor module includes a first capacitor, a second capacitor, and a third capacitor; the first capacitor and the fifth switch form a first loop; the second capacitor and the sixth switch are connected in series to form a second loop, and the third capacitor and the seventh switch are connected in series to form a third loop; the first loop, the second loop, and the third loop are connected in parallel to form a capacitor loop.

4. The compensated voltage stabilizing device for low-voltage distribution lines according to claim 3, characterized in that, The capacitor loop is arranged between the neutral line and the live wire of the low-voltage distribution line after being connected to the capacitor branch switch.

5. A compensated voltage stabilizing device for low-voltage distribution lines according to claim 1, characterized in that, The device also includes a first lightning arrester and a second lightning arrester; one end of the first lightning arrester is connected to the live wire of the low-voltage distribution line, and the other end is grounded; one end of the second lightning arrester is connected to the live wire of the low-voltage distribution line, and the other end is grounded.

6. The compensated voltage stabilizing device for low-voltage distribution lines according to claim 1, wherein The switch module includes a first switch, a second switch, a third switch, and a fourth switch connected in parallel; The contacts of the first switch, the contacts of the second switch, the contacts of the third switch, and the contacts of the fourth switch are all connected to the voltage regulating transformer; the coils of the first switch, the coils of the second switch, the coils of the third switch, and the coils of the fourth switch are all connected to the controller.

7. A compensated voltage stabilization device for a low-voltage distribution line according to claim 1, characterized in that, An air circuit breaker is also arranged between the voltage regulating tap of the voltage regulating transformer and the secondary side of the compensating transformer.

8. A compensated voltage stabilizing device for a low-voltage distribution line according to claim 1, characterized in that, The normally open contact of the bypass contactor is connected between the voltage regulating tap of the voltage regulating transformer and the live wire.

9. The compensated voltage stabilizing device for low-voltage distribution lines according to claim 8, wherein The normally open contact of the bypass contactor is connected to the secondary side of the compensating transformer through the normally closed contact of the bypass contactor.

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