Method and system for regulating voltage in medium and low voltage distribution network region

Abstract

The invention discloses a method and a system for regulating voltage in a medium and low voltage power distribution network region, which are characterized in that an execution device is installed in a target power supply region to detect the electric quantity information of the target power supply region, the electric quantity information is sent to a control device, and then the control device sends a voltage regulation request instruction according to the electric quantity information; and the control device is used for indicating the execution device to adjust and control the voltage of the target power supply area, so that the voltage of the target power supply area tends to be stable. According to the invention, the voltage of the specific target power supply area can be monitored in real time, and efficient management of the voltage in the specific target power supply area in the medium and low voltage distribution network is realized through a flexible control strategy, so that the voltage stability of the specific target power supply area in the medium and low voltage distribution network is ensured, and the power utilization quality and the power utilization experience of a user are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid voltage control, and in particular to a method and system for voltage regulation within a medium and low voltage distribution network. Background Art

[0002] The rural power grid in a specific area is characterized by many points, long lines, wide areas, dispersed loads, and concentrated power consumption periods, which makes the low voltage in rural areas in the specific area a long-term, dynamic, and systematic problem; at the same time, the rural power load in the region has obvious randomness, seasonality, and periodicity. The overall situation is low power load rate, large peak-to-valley difference, and low annual average load rate. The low voltage problem is prominent during peak power consumption periods.

[0003] At present, flexible AC transmission technology, which integrates power electronics technology, microprocessing and microelectronics technology, communication technology and control technology, is developed rapidly for flexible and rapid control of AC transmission. Equipment such as static VAR compensator, static synchronous series compensator and unified power flow controller can realize voltage control and power flow control, but its application occasions are mostly main grid construction such as high voltage and ultra-high voltage DC transmission. It is not very suitable for medium and low voltage distribution networks, especially it cannot guarantee the voltage stability of medium and low voltage distribution networks in specific power supply areas, and thus cannot guarantee the power quality and power experience of users. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a voltage regulation method and system in a medium and low voltage distribution network area, which can ensure the voltage stability in a specific target power supply area in the medium and low voltage distribution network, thereby improving the user's power quality and power experience.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a method for regulating voltage in a medium and low voltage distribution network area, which is applied to a control device and includes:

[0006] Receiving input-end power information and output-end power information of an execution device, wherein the execution device is arranged in a device in a target power supply area;

[0007] A voltage regulation request instruction is issued to the execution device according to the input end power information and the output end power information of the execution device; wherein the voltage regulation request instruction is used to instruct the execution device to adopt a control strategy to regulate and control the voltage of the target power supply area.

[0008] Specifically, the input terminal power information includes input terminal voltage, current and power data;

[0009] The output terminal power information includes output terminal voltage, current and power data.

[0010] As an improvement of the above solution, the step of issuing a voltage regulation request instruction to the execution device according to the input end power information and the output end power information of the execution device includes:

[0011] When the difference ratio between the input end power and the output end power of the execution device is higher than a preset threshold, a voltage regulation request instruction is issued to the execution device;

[0012] Alternatively, when the voltage of the target power supply area is lower than / higher than the standard power supply voltage, a voltage adjustment request instruction is sent to the execution device.

[0013] In order to solve the above technical problems, an embodiment of the present invention further provides a method for regulating voltage in a medium and low voltage distribution network area, which is applied to an execution device and includes:

[0014] Detecting the input end power information and the output end power information of the execution device, and sending the input end power information and the output end power information to the control device;

[0015] receiving a voltage regulation request instruction issued by the control device;

[0016] According to the voltage regulation request instruction, a control strategy is adopted to regulate and control the voltage of the target power supply area so that the voltage of the target power supply area tends to be stable.

[0017] As an improvement of the above solution, the control strategy is a control strategy based on an active power filter and a static synchronous compensator.

[0018] As an improvement of the above solution, the voltage of the target power supply area is regulated and controlled by using a control strategy according to the voltage regulation request instruction, including:

[0019] According to the voltage regulation request instruction, the control parameters of the active power filter and the static synchronous compensator are adjusted to regulate and control the voltage of the target power supply area so that the voltage of the target power supply area tends to be stable.

[0020] In order to solve the above technical problems, an embodiment of the present invention further provides a voltage regulation system in a medium and low voltage distribution network area, comprising a voltage regulation device, wherein the voltage regulation device comprises a control device and an execution device, wherein the control device and the execution device are communicatively connected; the execution device is arranged in a device in a target power supply area;

[0021] The execution device is used to detect the power information of the target power supply area and send the power information to the control device;

[0022] The control device is used to receive the power information sent by the execution device and issue a voltage regulation request instruction based on the power information; wherein the voltage regulation request instruction is used to instruct the execution device to regulate and control the voltage of the target power supply area so that the voltage of the target power supply area tends to be stable.

[0023] As an improvement of the above solution, the execution device includes an active power filter and a static synchronous compensator.

[0024] As an improvement of the above solution, the equipment in the target power supply area includes an inverter, a converter, an electric voltage regulator and a transformer.

[0025] Compared with the prior art, the embodiment of the present invention provides a method and system for regulating voltage in a medium and low voltage distribution network area, which installs an execution device in a target power supply area to detect the power information of the target power supply area, and sends the power information to the control device, and then the control device issues a voltage regulation request instruction according to the power information, which is used to instruct the execution device to regulate and control the voltage of the target power supply area so that the voltage of the target power supply area tends to be stable. The present invention can monitor the voltage of a specific target power supply area in real time, and realize efficient management of the voltage in a specific target power supply area in a medium and low voltage distribution network through a flexible control strategy, thereby ensuring the voltage stability of a specific target power supply area in a medium and low voltage distribution network, thereby improving the power quality and experience of users. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solution of the present invention, the drawings used in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 This is a flow chart of a method for voltage regulation in a medium and low voltage distribution network area provided by an embodiment of the present invention;

[0028] Figure 2 It is another flow chart of a method for voltage regulation in a medium and low voltage distribution network area provided by an embodiment of the present invention;

[0029] Figure 3 is another flow chart of a method for voltage regulation in a medium and low voltage distribution network area provided by an embodiment of the present invention;

[0030] Figure 4 It is a structural block diagram of a voltage regulation system within a medium and low voltage distribution network area provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] See also Figure 1 , Figure 1 1 is a flow chart of a method for regulating voltage in a medium- and low-voltage distribution network area provided by an embodiment of the present invention. The method for regulating voltage in a medium- and low-voltage distribution network area is applied to a control device and includes steps S101 to S102:

[0033] S101, receiving input end power information and output end power information of an execution device; wherein the execution device is arranged in a device in a target power supply area;

[0034] Specifically, the input terminal power information includes input terminal voltage, current and power data;

[0035] The output terminal power information includes output terminal voltage, current and power data.

[0036] It is worth noting that information such as the input voltage, current and power data of the actuator can reflect the overall power demand and power supply environment of the target power supply area; while the output voltage, current and power data of the actuator can display the current power output of the target power supply area.

[0037] S102. Based on the input power information and output power information of the execution device, a voltage regulation request instruction is issued to the execution device; wherein the voltage regulation request instruction is used to instruct the execution device to adopt a control strategy to regulate and control the voltage of the target power supply area.

[0038] In an optional embodiment, the step of issuing a voltage regulation request instruction to the execution device according to the input end power information and the output end power information of the execution device includes:

[0039] When the difference ratio between the input end power and the output end power of the execution device is higher than a preset threshold, a voltage regulation request instruction is issued to the execution device;

[0040] Alternatively, when the voltage of the target power supply area is lower than / higher than the standard power supply voltage, a voltage adjustment request instruction is sent to the execution device.

[0041] It should be noted that the standard power supply voltage is specifically the voltage specified by the national standard (such as 220V+7%, -10% for a single-phase system of a medium and low voltage distribution network, and 380V±7% for a three-phase system of a medium and low voltage distribution network).

[0042] It is worth noting that the voltage regulation request instruction of the control device is based on a comprehensive analysis of the power information at the input and output ends of the execution device. This process not only focuses on the value of the information itself, but also pays more attention to the relationship and changes between them to ensure the timeliness and effectiveness of voltage regulation.

[0043] On the one hand, when the difference between the input power and output power of the actuator is higher than the preset threshold, the control device will identify this phenomenon as a potential voltage instability risk. This difference reflects the degree of matching between the load condition of the power supply system and the input energy. If the difference is too large, it may cause voltage fluctuations in the power supply area and even affect the user's power experience. In this case, the control device will automatically send a voltage adjustment request instruction to the actuator, instructing it to adopt a corresponding control strategy to adjust the voltage and restore the balance, thereby ensuring the safety and reliability of the power system operation.

[0044] On the other hand, when the output voltage of the actuator is lower or higher than the standard power supply voltage, in the actual power supply process, the standard power supply voltage is an important indicator for determining the power supply quality. If the voltage in the target power supply area fluctuates abnormally, it will obviously affect the normal operation of the power supply equipment and the power safety of users. Therefore, when the output voltage significantly deviates from the standard power supply voltage range, the control device will quickly issue a voltage adjustment request instruction, requiring the actuator to immediately adjust the voltage to restore it to a stable value.

[0045] In an optional embodiment, the difference ratio between the input terminal power and the output terminal power of the execution device is specifically the difference ratio between the input terminal voltage and the output terminal voltage of the execution device, which is calculated by the following formula:

[0046] K=i / [(U2-U1)-ΔU ref ],i≤I max ;

[0047] Among them, K represents the proportional coefficient. The larger the K value, the greater the voltage fluctuation in the target power supply area; U1 represents the input voltage of the actuator; U2 represents the output voltage of the actuator; ΔU ref represents a preset voltage difference (or a preset voltage threshold of a target power supply area); I max Represents the current limit.

[0048] It should be noted that the input voltage detected by the execution device can represent the voltage received by the target power supply area, usually from a power supply such as a power grid or a transformer, and the output voltage can represent the voltage provided by the target power supply area to the connected load or device. The voltage difference between the input and output terminals is the voltage difference of the target power supply area, and the voltage of the target power supply area usually refers to the voltage difference between the input and output terminals of the area.

[0049] It is worth noting that the voltage difference threshold of the execution device (i.e., the voltage threshold of the target power supply area) can be designed based on factors such as different time periods throughout the day, different seasons throughout the year, and different energy equipment connected to the distribution network.

[0050] For example, if only the photovoltaic access scenario is considered, considering the different light intensities at different times of the day, when there are more photovoltaic accesses in a certain area, the voltage threshold of the execution device is divided according to the daytime and nighttime periods. It can be set to 230V during the day and 221V at night to ensure the user's electricity experience. If both wind power generation and photovoltaic access scenarios are considered at the same time, considering that due to wind power generation site selection rules and other reasons, wind power generation equipment may supply energy to the grid through transmission lines throughout the day, so the voltage threshold can be set to 230V regardless of the time period. For ordinary users in some areas, and without photovoltaic access or with a small amount of access, the voltage threshold can be set to 224V.

[0051] Exemplarily, the execution device is set in the equipment of the target power supply area, and the control device receives the input power information and output power information of the execution device, and then judges the difference ratio between the input voltage and the output voltage of the execution device. If the difference ratio is too large, indicating that the voltage difference of the target power supply area exceeds the preset voltage difference, a voltage adjustment request instruction is sent to the execution device in the current target area. After receiving the voltage adjustment request instruction, the execution device adjusts the voltage and other power information in the current target power supply area according to the instruction. It should be noted that the current target power supply area is the power supply area where the execution device is located.

[0052] In summary, the embodiment of the present invention can flexibly respond to the ever-changing power supply demand and external environment and issue voltage regulation request instructions through the comprehensive analysis of the input power information and output power information of the execution device in the target power supply area by the control device, thereby ensuring that the voltage in a single target power supply area is stable within a reasonable range, thereby effectively improving the overall operating efficiency of the power system.

[0053] See also Figure 2 , Figure 2 It is another flow chart of a method for voltage regulation in a medium and low voltage distribution network area provided by an embodiment of the present invention, which is applied to an execution device and includes steps S201 to S203:

[0054] S201, detecting the input end power information and the output end power information of the execution device, and sending the input end power information and the output end power information to the control device;

[0055] S202, receiving a voltage regulation request instruction issued by the control device;

[0056] S203: According to the voltage regulation request instruction, a control strategy is adopted to regulate and control the voltage of the target power supply area so that the voltage of the target power supply area tends to be stable.

[0057] Exemplarily, the execution device itself detects the output power information of the execution device in real time. Specifically, the execution device continuously detects the key parameters such as the current, voltage and power of its own output end, and sends them to the control device quickly and accurately. After receiving the output power information, the control device will analyze the current power state according to the preset logic and generate the corresponding voltage adjustment request instruction. According to the received voltage adjustment request instruction, the execution device will adjust and control the voltage of the target power supply area according to the predetermined control strategy, and adjust the voltage of the target area to make it tend to a stable state. For example, the execution device may increase or decrease the power output, adjust the power factor or change the load distribution according to the real-time power information to ensure that the voltage of the target area is always maintained within a safe range.

[0058] In an optional embodiment, the control strategy is a control strategy based on an active power filter and a static synchronous compensator.

[0059] Furthermore, the voltage of the target power supply area is regulated and controlled by adopting a control strategy according to the voltage regulation request instruction, including:

[0060] According to the voltage regulation request instruction, the control parameters of the active power filter and the static synchronous compensator are adjusted to regulate the voltage of the target power supply area so that the voltage of the target power supply area tends to be stable.

[0061] It should be noted that the active power filter (APF) is a new type of power electronic device used to dynamically suppress harmonics and compensate for reactive power. It can compensate for harmonics with varying sizes and frequencies and varying reactive power. The static synchronous compensator (STATCOM) is one of the core devices and core technologies of the flexible AC transmission system. The static synchronous compensator uses a new generation of power electronic devices, such as gate turn-off thyristors (GTOs), insulated gate bipolar transistors (IGBTs), and integrated gate-commutated thyristors (IGCTs), and uses modern control technology. Its role in the power grid system is to compensate for reactive power, improve the voltage stability of the grid system, and improve system performance.

[0062] It is worth noting that using APF to compensate harmonics and STATCOM to adjust reactive power can simultaneously improve power quality, enhance the voltage stability of the power grid, and ensure stable power supply to the load end. The basic principle of its control strategy is to use the parallel side circuit to obtain active power for voltage compensation from the line, and to achieve load side voltage compensation by using direct voltage control or resonant control on the series side, thereby achieving the improvement of the amplitude of the medium and low voltage distribution network and the elimination of grid voltage harmonics.

[0063] For example, in the medium and low voltage distribution network system, a static synchronous compensator is connected in parallel to obtain active power from the main power line to compensate the load; an active power filter is installed in front of the load to compensate the grid voltage in series. In specific implementation, the voltage can be monitored and adjusted in real time to keep the voltage within the set range.

[0064] For example, taking a medium and low voltage distribution network system as a four-arm three-phase four-wire system (TP-FW) as an example, the control strategy based on active power filter and static synchronous compensator (APF-STATCOM) is described:

[0065] The four-arm three-phase four-wire system uses four wires to provide the corresponding three-phase AC power supply. The APF continuously monitors the current waveform in the system and uses the harmonic current detection method to detect the harmonic components. Then, based on the signal processing results, a reference current signal is generated through a control algorithm (such as PI control, i.e. proportional-integral control), which compensates for the harmonic current in real time and injects a current opposite to the harmonic current to achieve current waveform correction, so that the system current is as close to a pure sinusoidal waveform as possible.

[0066] It is worth noting that the traditional harmonic current detection method relies on the instantaneous reactive power theory, ignores the zero-sequence component during three-phase distortion, and is very susceptible to voltage distortion and asymmetry. This can lead to significant inaccuracies in the detection results, making the output difficult to trust. In an embodiment of the present invention, the sine and cosine signal generation phase-locked loop (PLL) is integrated into the harmonic detection algorithm based on the instantaneous reactive power theory, i.e. p -i q In the harmonic current detection method, accurate detection using PLL can be ensured.

[0067] At the same time, STATCOM is used to monitor the power supply voltage of the distribution network. According to the voltage changes, STATCOM adopts voltage source control technology to achieve independent reactive power output. According to the voltage source control strategy, the output of STATCOM is adjusted by setting the correct reference voltage to stabilize the system voltage.

[0068] In summary, the embodiment of the present invention monitors the power information of the power supply area in real time through the execution device and responds to the voltage regulation request instruction of the control device, and adopts a control strategy based on active power filter and static synchronous compensator to quickly adjust the voltage in a single target area, ensuring that the voltage in a specific area remains within a reasonable range, thereby improving the reliability and quality of power supply.

[0069] See also Figure 3 , Figure 3 is another flow chart of a method for voltage regulation in a medium and low voltage distribution network area provided by an embodiment of the present invention, such as Figure 3 As shown, first, the execution device detects its own input end power information and output end power information and sends them to the control device, then the control device receives the input end power information and output end power information sent by the execution device, and generates a voltage regulation request instruction and sends it to the execution device, finally, the execution device receives the voltage regulation request instruction, and adopts a control strategy to regulate and control the voltage of the target power supply area according to the voltage regulation request instruction, so that the voltage of the target power supply area tends to be stable.

[0070] It is worth noting that the voltage regulation method in a medium- and low-voltage distribution network area provided by an embodiment of the present invention ensures the stability of the voltage in a specific power supply area through real-time feedback and adaptive control. In practical applications, the grid voltage may drop in a specific area (a specific area in the distribution network) due to a sudden increase in the amount of load access. Using the voltage regulation method in a medium- and low-voltage distribution network area provided by an embodiment of the present invention, the output voltage can be adjusted by direct voltage control or resonance control, so that the output voltage is increased to the standard voltage range.

[0071] See also Figure 4 , Figure 4 It is a structural block diagram of a voltage regulation system in a medium and low voltage distribution network area provided by an embodiment of the present invention. The voltage regulation system in the medium and low voltage distribution network area includes a voltage regulation device 3, the voltage regulation device includes a control device 301 and an execution device 302, the control device 301 and the execution device 302 are communicatively connected; the execution device 302 is set in the equipment in the target power supply area;

[0072] The execution device 302 is used to detect the power information of the target power supply area and send the power information to the control device 301;

[0073] The control device 301 is used to receive the power information sent by the execution device 302, and issue a voltage regulation request instruction based on the power information; wherein the voltage regulation request instruction is used to instruct the execution device 302 to regulate and control the voltage of the target power supply area so that the voltage of the target power supply area tends to be stable.

[0074] In a preferred embodiment, the equipment in the target power supply area includes an inverter, a converter, an electric voltage regulator and a transformer.

[0075] As an improvement of the above solution, the execution device 302 includes an active power filter and a static synchronous compensator.

[0076] Exemplarily, the power demand and voltage stability requirements of the target power supply area are determined, the voltage threshold is set in advance, and the actuators are deployed in the target power supply area to ensure that they are tightly integrated with the load equipment (such as inverters, converters, etc.) for real-time monitoring of current, voltage and power factor, and obtaining power information. Then, a control device is used to receive the power information from the actuator to determine the voltage state, and compare it with the set target voltage to generate a voltage regulation request instruction. The actuator adjusts the adjustment parameters of the APF and STATCOM according to the received voltage regulation request instruction, thereby achieving voltage stability.

[0077] It should be noted that the working principle and beneficial effects of the medium and low voltage distribution network regional voltage regulation system provided by the embodiment of the present invention correspond one to one with the medium and low voltage distribution network regional voltage regulation method of the above embodiment, and therefore will not be repeated herein.

[0078] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for regulating voltage in a medium and low voltage distribution network area, characterized in that: Applicable to control devices, including: Receiving input-end power information and output-end power information of an execution device, wherein the execution device is arranged in a device in a target power supply area; A voltage regulation request instruction is issued to the execution device according to the input end power information and the output end power information of the execution device; wherein the voltage regulation request instruction is used to instruct the execution device to adopt a control strategy to regulate and control the voltage of the target power supply area.

2. The method for regulating voltage in a medium and low voltage distribution network area according to claim 1, characterized in that: The input terminal power information includes input terminal voltage, current and power data; The output terminal power information includes output terminal voltage, current and power data.

3. The method for regulating voltage in a medium and low voltage distribution network area according to claim 2, characterized in that: The step of issuing a voltage regulation request instruction to the execution device according to the input end power information and the output end power information of the execution device comprises: When the difference ratio between the input end power and the output end power of the execution device is higher than a preset threshold, a voltage regulation request instruction is issued to the execution device; Alternatively, when the voltage of the target power supply area is lower than / higher than the standard power supply voltage, a voltage adjustment request instruction is sent to the execution device.

4. A method for regulating voltage in a medium and low voltage distribution network area, characterized in that: Applicable to actuators, including: Detecting the input end power information and the output end power information of the execution device, and sending the input end power information and the output end power information to the control device; receiving a voltage regulation request instruction issued by the control device; According to the voltage regulation request instruction, a control strategy is adopted to regulate and control the voltage of the target power supply area so that the voltage of the target power supply area tends to be stable.

5. The method for regulating voltage in a medium and low voltage distribution network area according to claim 4, characterized in that: The control strategy is a control strategy based on an active power filter and a static synchronous compensator.

6. The method for regulating voltage in a medium and low voltage distribution network area according to claim 5, characterized in that: The step of adjusting and controlling the voltage of the target power supply area by adopting a control strategy according to the voltage adjustment request instruction includes: According to the voltage regulation request instruction, the control parameters of the active power filter and the static synchronous compensator are adjusted to regulate and control the voltage of the target power supply area so that the voltage of the target power supply area tends to be stable.

7. A voltage regulation system in a medium and low voltage distribution network area, characterized in that: The voltage regulating device comprises a control device and an execution device, wherein the control device and the execution device are in communication connection; the execution device is arranged in a device in a target power supply area; The execution device is used to detect the power information of the target power supply area and send the power information to the control device; The control device is used to receive the power information sent by the execution device and issue a voltage regulation request instruction based on the power information; wherein the voltage regulation request instruction is used to instruct the execution device to regulate and control the voltage of the target power supply area so that the voltage of the target power supply area tends to be stable.

8. The regional voltage regulation system for medium and low voltage distribution networks according to claim 7, characterized in that: The execution device includes an active power filter and a static synchronous compensator.

9. The regional voltage regulation system for medium and low voltage distribution networks according to claim 7, characterized in that: The equipment in the target power supply area includes an inverter, a converter, an electric voltage regulator and a transformer.

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