System and method for automatically stabilizing voltage of low-voltage distribution line

Abstract

The invention provides a system and a method for automatically stabilizing the voltage of a low-voltage distribution line. The system comprises a voltage regulating transformer T, six capacitors C1-C6 and fifteen power switches K1-K15, the voltage regulating transformer T is provided with a primary winding L1 and a secondary winding L2, the secondary winding is serially connected into the phase line L, the primary winding L1 is subdivided into five parts of L11-L15 and is connected into a circuit through the combination of the power switches K1-K9, multi-gear voltage boosting and reducing regulation is realized, and the capacitors C1-C6 and the power switches K10-K15 are used for realizing six-stage reactive power compensation. According to the invention, through combination of reactive power compensation and voltage regulation, the line loss of the low-voltage power distribution network is reduced, and the electric energy quality is improved.

Description

Technical Field

[0001] The present application relates to the technical field of low-voltage power distribution, and in particular to a system and method for automatic voltage stabilization of a low-voltage power distribution line. Background Art

[0002] The statements in this section merely provide background technical information related to the present application and do not necessarily constitute prior art.

[0003] With the continuous development of the power system, users have higher and higher requirements for voltage stability. In the low-voltage distribution network, due to various factors such as large power supply radius, unstable load, and aging lines, the problem of voltage fluctuation has become increasingly prominent, which also brings about the problem of low line power factor. Traditional solutions, such as erecting poles and towers, extending 10kV lines, and adding large-capacity transformers to stabilize voltage, not only require large investments, but also have long construction periods, and are difficult to meet the rapidly changing needs of the power grid. To address the problem of low power factor, compensation devices are generally added to the transformer end of the substation, but the problem of low power factor of the line is difficult to solve. Therefore, a more economical, convenient and efficient solution is needed to deal with this problem. Summary of the invention

[0004] In order to solve or partially solve the problems in the background technology, the present application proposes a low-voltage distribution line voltage automatic stabilization system and method.

[0005] The present application provides a low-voltage distribution line voltage automatic stabilization system, comprising: a voltage regulating transformer T, six capacitors C1-C6, and fifteen power switches K1-K15;

[0006] The voltage regulating transformer T has a primary winding L1 and a secondary winding L2. The secondary winding is connected in series to the phase line L. The primary winding L1 is subdivided into five parts, L11-L15, and connected to the circuit through a combination of power switches K1-K9 to achieve multi-speed step-up and step-down regulation:

[0007] Capacitors C1-C6 and power switches K10-K15 are used to achieve six-level reactive power compensation.

[0008] Preferably, the capacitors C1-C6 and the power switches K10-K15 are matched one by one and connected in series to form a power compensation branch, and the six power compensation branches are connected in parallel between the phase line L and the neutral line N;

[0009] The power switch K2 is connected in series with the primary winding L1, and is connected in series with the power switches K4-K9 through the separation taps of L11-L15 and then connected to the neutral line N, forming a five-speed voltage regulation branch. The power switches K4 and K9 are connected in series with the initial end and the final section of the primary winding L1;

[0010] The power switch K1 is connected in parallel to the secondary winding L2, and the power switch K3 is connected in parallel to the input end of K2 and the end of the primary winding L1.

[0011] Preferably, the voltage regulating transformer T is also provided with a controller and a Bluetooth communication module, a 4G mobile communication module, a micro-power wireless communication module, a power line carrier communication module and an RS-485 communication module electrically connected to the controller.

[0012] The present application also provides a method for automatically stabilizing the voltage of a low-voltage distribution line, the specific steps of which are as follows:

[0013] Step 1: When the controller detects that the power factor is lower than the preset value Q1 and the output voltage is lower than the preset voltage U1, reactive power compensation is performed by gradually switching capacitors C1-C6, and the output voltage is gradually increased by controlling the switching of each part of L11-L15 of the primary winding;

[0014] Step 2: When the controller detects that the power factor is normal but the output voltage is higher than the preset voltage U2, the output voltage is gradually reduced by controlling the switching of each part L11-L15 of the primary winding;

[0015] Step 3: When the controller detects that the power factor is normal but the output voltage is lower than the preset voltage U1, the output voltage is gradually raised by controlling the switching of each part L11-L15 of the primary winding;

[0016] Step 4: When the controller detects that the output voltage is normal but the power factor is higher than the preset value Q2, the capacitors C1-C6 are removed step by step to maintain a reasonable power factor.

[0017] Preferably, in step 1 and step 4, the controller calculates the required or excess reactive compensation capacity, and then calculates the number of capacitors that need to be switched, and closes or opens the power switches of the corresponding power compensation branches respectively.

[0018] Preferably, in step 1 to step 3, the specific steps of adjusting the voltage step by step are as follows:

[0019] When the output voltage needs to be increased by ΔU, K1, K3, K4-K8 are disconnected, K2 and K9 are closed, and the five parts L11-L15 of the primary winding bear the input voltage;

[0020] When the output voltage needs to be increased by 2*ΔU, K1, K3, K4-K7, and K9 are disconnected, K2 and K8 are closed, and the four parts L11-L14 of the primary winding bear the input voltage;

[0021] When the output voltage needs to be increased by 3*ΔU, K1, K3, K4-K6, K8, K9 are disconnected, K2 and K7 are closed, and the three parts L11-L13 of the primary winding bear the input voltage;

[0022] When the output voltage needs to be increased by 4*ΔU, K1, K3, K4, K5, K7-K9 are disconnected, K2 and K6 are closed, and L11 and L12 of the primary winding bear the input voltage;

[0023] When the output voltage needs to be increased by 5*ΔU, K1, K3, K4, K6-K9 are disconnected, K2 and K5 are closed, and the L11 part of the primary winding bears the input voltage;

[0024] When the output voltage needs to be reduced, the reverse logic of the above operation is followed.

[0025] Preferably, if the voltage regulating transformer T has reached the limit and the output voltage is still lower than the preset voltage U1, the capacitors C1-C6 are continuously added to further increase the voltage through the capacitance rise effect.

[0026] Preferably, the controller selects any one or more of Bluetooth, 4G, micro-power wireless, power line carrier, and RS-485 for remote transmission of data according to actual needs.

[0027] Compared with the prior art, the beneficial effects of this application are:

[0028] (1) The present application achieves fine voltage regulation with small step difference and no impact by subdividing the primary winding of the transformer and utilizing a combination of power switches, thereby saving transformer size and reducing product cost.

[0029] (2) The present application realizes a 10-level voltage regulation function, with a wide voltage regulation range, small regulation step difference, and high voltage stabilization accuracy.

[0030] (3) This application reduces line losses in low-voltage distribution networks and improves power quality by combining reactive power compensation with voltage regulation.

[0031] (4) This application supports multiple communication methods, meeting local and remote data transmission and control requirements, and enhancing the system's remote monitoring and control capabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0033] Figure 1 This is the system circuit schematic diagram of this application.

[0034] Figure 2 This is a schematic diagram of the communication system composition of this application.

[0035] Figure 3Schematic diagram of the method flow of this application. DETAILED DESCRIPTION

[0036] The present application is further described below in conjunction with the accompanying drawings and embodiments.

[0037] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0038] In the present disclosure, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present disclosure, and do not specifically refer to any part or element in the present disclosure and should not be understood as limitations on the present disclosure.

[0039] Example 1

[0040] like Figures 1 to 3 As shown, the present application provides a low-voltage distribution line voltage automatic stabilization system, including: a voltage regulating transformer T, six capacitors C1-C6 and fifteen power switches K1-K15.

[0041] The voltage regulating transformer T has a primary winding L1 and a secondary winding L2. The secondary winding is connected in series to the phase line L. The primary winding L1 is subdivided into five parts, L11-L15, and is connected to the circuit through a combination of power switches K1-K9 to achieve 10-speed step-up and step-down regulation. Capacitors C1-C6 and power switches K10-K15 are used to achieve six-level reactive power compensation.

[0042] Specifically, the capacitors C1-C6 and the power switches K10-K15 are matched and connected in series to form a power compensation branch, and the six power compensation branches are connected in parallel between the phase line L and the neutral line N;

[0043] The power switch K2 is connected in series with the primary winding L1, and is connected in series with the power switches K4-K9 through the separation taps of L11-L15 and then connected to the neutral line N, forming a five-speed voltage regulation branch. The power switches K4 and K9 are connected in series with the initial end and the final section of the primary winding L1;

[0044] The power switch K1 is connected in parallel to the secondary winding L2, and the power switch K3 is connected in parallel to the input end of K2 and the end of the primary winding L1.

[0045] The voltage regulating transformer T is also provided with a controller and a Bluetooth communication module, a 4G mobile communication module, a micro-power wireless communication module, a power line carrier communication module and an RS-485 communication module electrically connected to the controller.

[0046] This application monitors the power factor, input voltage and output voltage of the access point of the low-voltage distribution line in real time. First, the power factor is improved through capacitor compensation. If the input voltage exceeds a reasonable range, the output voltage is adjusted by adjusting the transformer to ensure voltage stability. The system supports multiple communication methods and supports multiple communication protocols such as Bluetooth, 4G, micro power, carrier, 485, etc., which is convenient for local operation and remote data transmission and control, effectively improving the power quality and operation efficiency of the low-voltage distribution line, and has broad application prospects and significant technical advantages.

[0047] Based on the above-mentioned low-voltage distribution line voltage automatic stabilization system, the present application also provides a low-voltage distribution line voltage automatic stabilization method, including the following steps:

[0048] Step 1: When the controller detects that the power factor is lower than the preset value Q1 and the output voltage is lower than the preset voltage U1, reactive power compensation is performed by gradually switching capacitors C1-C6, and the output voltage is gradually increased by controlling the switching of each part of L11-L15 of the primary winding;

[0049] Step 2: When the controller detects that the power factor is normal but the output voltage is higher than the preset voltage U2, the output voltage is gradually reduced by controlling the switching of each part L11-L15 of the primary winding;

[0050] Step 3: When the controller detects that the power factor is normal but the output voltage is lower than the preset voltage U1, the output voltage is gradually raised by controlling the switching of each part L11-L15 of the primary winding;

[0051] Step 4: When the controller detects that the output voltage is normal but the power factor is higher than the preset value Q2, the capacitors C1-C6 are removed step by step to maintain a reasonable power factor.

[0052] In step 1 and step 4, the controller calculates the required or excess reactive compensation capacity, and then calculates the number of capacitors that need to be switched, and respectively closes or disconnects the power switches of the corresponding power compensation branches. Specifically, if one capacitor is needed, the switch K10 is closed; if two capacitors need to be put into operation, the switches K10 and K11 are closed; if three capacitors need to be put into operation, the switches K10- and K12 are closed; if four capacitors need to be put into operation, the switches K10-K13 are closed; if five capacitors need to be put into operation, the switches K10-K14 are closed; if six capacitors need to be put into operation, the switches K10-K15 are closed; if the capacitor needs to be cut off, the operation is performed according to the opposite logic.

[0053] In step 1 to step 3, the specific steps of adjusting the voltage step by step are as follows:

[0054] When the output voltage needs to be increased by ΔU, K1, K3, K4-K8 are disconnected, K2 and K9 are closed, and the five parts L11-L15 of the primary winding bear the input voltage;

[0055] When the output voltage needs to be increased by 2*ΔU, K1, K3, K4-K7, and K9 are disconnected, K2 and K8 are closed, and the four parts L11-L14 of the primary winding bear the input voltage;

[0056] When the output voltage needs to be increased by 3*ΔU, K1, K3, K4-K6, K8, K9 are disconnected, K2 and K7 are closed, and the three parts L11-L13 of the primary winding bear the input voltage;

[0057] When the output voltage needs to be increased by 4*ΔU, K1, K3, K4, K5, K7-K9 are disconnected, K2 and K6 are closed, and L11 and L12 of the primary winding bear the input voltage;

[0058] When the output voltage needs to be increased by 5*ΔU, K1, K3, K4, K6-K9 are disconnected, K2 and K5 are closed, and the L11 part of the primary winding bears the input voltage.

[0059] When the output voltage needs to be reduced, the reverse logic of the above operation is followed. For example, when the output voltage is changed from being increased by 5*ΔU to being increased by 4*ΔU, K5 is disconnected and K6 is closed.

[0060] It is worth noting that the number of turns of the coils L11-L15 is set according to a preset ratio to achieve the effect of increasing the output voltage by an equal amount when L15-L11 are disconnected in sequence.

[0061] Preferably, if the voltage regulating transformer T has reached the limit of regulation and the output voltage is still lower than the preset voltage U1, the capacitors C1-C6 are continuously added to further increase the voltage through the capacitance rise effect.

[0062] The controller selects any one or more of Bluetooth, 4G, micro-power wireless, power line carrier, and RS-485 for remote data transmission according to actual needs to meet the communication needs in different scenarios.

[0063] Specifically, through short-range communication technologies such as Bluetooth, rapid configuration, status monitoring and fault diagnosis of on-site equipment can be achieved, improving the convenience and immediacy of local operations; using 4G mobile communications or power line carrier communications, real-time transmission of remote data and remote monitoring of system status can be achieved, allowing operators to control and manage the system at a location far away from the site, enhancing the flexibility and maintainability of the system; in specific environments, such as low power requirements or areas with limited signal coverage, the system can use micro-power wireless communication technology to achieve low-power, short-distance communication between devices, reducing the overall energy consumption of the system; for data transmission scenarios that require high reliability and stability, the system supports RS-485 wired communication protocol to ensure the accuracy and integrity of data transmission, which is suitable for the collection of key data and the sending of control instructions.

[0064] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0065] Although the above describes the specific implementation methods of the present application in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present application. Technical personnel in the relevant field should understand that on the basis of the technical solution of the present application, various modifications or deformations that can be made by technical personnel in this field without creative work are still within the scope of protection of the present application.

Claims

1. A low voltage distribution line voltage automatic stabilization system, characterized in that: include: A voltage regulating transformer T, six capacitors C1-C6 and fifteen power switches K1-K15; The voltage regulating transformer T has a primary winding L1 and a secondary winding L2. The secondary winding is connected in series to the phase line L. The primary winding L1 is subdivided into five parts, L11-L15, and connected to the circuit through a combination of power switches K1-K9 to achieve multi-speed step-up and step-down regulation: Capacitors C1-C6 and power switches K10-K15 are used to achieve six-level reactive power compensation.

2. The automatic voltage stabilization system for low-voltage distribution lines according to claim 1 is characterized in that: The capacitors C1-C6 and the power switches K10-K15 are matched and connected in series to form a power compensation branch, and the six power compensation branches are connected in parallel between the phase line L and the neutral line N; The power switch K2 is connected in series with the primary winding L1, and is connected in series with the power switches K4-K9 through the separation taps of L11-L15 and then connected to the neutral line N, forming a five-speed voltage regulation branch. The power switches K4 and K9 are connected in series with the initial end and the final section of the primary winding L1; The power switch K1 is connected in parallel to the secondary winding L2, and the power switch K3 is connected in parallel to the input end of K2 and the end of the primary winding L1.

3. The low voltage distribution line voltage automatic stabilization system according to claim 2 is characterized in that: The voltage regulating transformer T is also provided with a controller and a Bluetooth communication module, a 4G mobile communication module, a micro-power wireless communication module, a power line carrier communication module and an RS-485 communication module electrically connected to the controller.

4. A voltage automatic stabilization method for a low-voltage distribution line voltage automatic stabilization system, characterized in that: A low-voltage distribution line voltage automatic stabilization system according to claim 3 comprises the following steps: Step 1: When the controller detects that the power factor is lower than the preset value Q1 and the output voltage is lower than the preset voltage U1, reactive power compensation is performed by gradually switching capacitors C1-C6, and the output voltage is gradually increased by controlling the switching of each part of L11-L15 of the primary winding; Step 2: When the controller detects that the power factor is normal but the output voltage is higher than the preset voltage U2, the output voltage is gradually reduced by controlling the switching of each part L11-L15 of the primary winding; Step 3: When the controller detects that the power factor is normal but the output voltage is lower than the preset voltage U1, the output voltage is gradually raised by controlling the switching of each part L11-L15 of the primary winding; Step 4: When the controller detects that the output voltage is normal but the power factor is higher than the preset value Q2, the capacitors C1-C6 are removed step by step to maintain a reasonable power factor.

5. A method for automatic voltage stabilization of a low-voltage distribution line according to claim 4, characterized in that: In step 1 and step 4, the controller calculates the required or excess reactive compensation capacity, and then calculates the number of capacitors that need to be switched, and closes or opens the power switches of the corresponding power compensation branches respectively.

6. A method for automatic voltage stabilization of a low-voltage distribution line according to claim 4, characterized in that: In step 1 to step 3, the specific steps of adjusting the voltage step by step are as follows: When the output voltage needs to be increased by ΔU, K1, K3, K4-K8 are disconnected, K2 and K9 are closed, and the five parts L11-L15 of the primary winding bear the input voltage; When the output voltage needs to be increased by 2*ΔU, K1, K3, K4-K7, and K9 are disconnected, K2 and K8 are closed, and the four parts L11-L14 of the primary winding bear the input voltage; When the output voltage needs to be increased by 3*ΔU, K1, K3, K4-K6, K8, K9 are disconnected, K2 and K7 are closed, and the three parts L11-L13 of the primary winding bear the input voltage; When the output voltage needs to be increased by 4*ΔU, K1, K3, K4, K5, K7-K9 are disconnected, K2 and K6 are closed, and L11 and L12 of the primary winding bear the input voltage; When the output voltage needs to be increased by 5*ΔU, K1, K3, K4, K6-K9 are disconnected, K2 and K5 are closed, and the L11 part of the primary winding bears the input voltage; When the output voltage needs to be reduced, the reverse logic of the above operation is followed.

7. A method for automatic voltage stabilization of a low-voltage distribution line according to claim 4, characterized in that: If the voltage regulating transformer T has reached the limit of regulation and the output voltage is still lower than the preset voltage U1, the capacitors C1-C6 are continuously added to further increase the voltage through the capacitance rise effect.

8. A method for automatic voltage stabilization of a low-voltage distribution line according to claim 4, characterized in that: The controller selects any one or more of Bluetooth, 4G, micro-power wireless, power line carrier, and RS-485 for remote data transmission according to actual needs.

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