Voltage regulation method and device based on real-time power flow change of low-voltage side of main transformer

Abstract

The invention relates to the technical field of power grid voltage regulation, in particular to a voltage regulation method and device based on real-time power flow change of a low-voltage side of a main transformer. The method comprises the steps of collecting power flow parameters of a low-voltage side of a main transformer in real time; constructing a power flow parameter curve according to the power flow parameters; setting an AVC strategy limit value; according to the power flow parameter curve, determining a voltage regulation strategy adaptive to a power flow bidirectional flow scene; according to the voltage regulation strategy and the AVC strategy limit value, reactive power regulation equipment associated with the low-voltage side of the main transformer is controlled to act, and voltage regulation is achieved. According to the invention, the problem of voltage out-of-limit caused by bidirectional tidal current flow of a power grid after a large number of distributed photovoltaic systems are accessed can be solved.

Description

Technical Field

[0001] This invention relates to the technical field of power grid voltage regulation, and in particular to a voltage regulation method and apparatus based on real-time power flow changes on the low-voltage side of the main transformer. Background Technology

[0002] The power flow in a distribution network is unidirectional, with electrical energy flowing from the substation bus to the load nodes, and the main grid voltage is always higher than the distribution grid voltage. However, the large-scale integration of distributed photovoltaic (PV) systems changes the power flow to bidirectional. When PV power generation exceeds load demand, the power flow can reverse from the load nodes back to the substation, sometimes even resulting in the distribution grid voltage being higher than the main grid voltage. Furthermore, PV power generation is affected by natural factors such as sunlight and cloud cover, leading to large fluctuations in output power and posing new challenges to grid voltage regulation.

[0003] Currently, power grid voltage regulation mainly relies on the Automatic Voltage Control (AVC) system. As a core means of improving voltage quality, the AVC system collects real-time information such as substation bus voltage, reactive power data, and switch status through the Supervisory Control and Data Acquisition (SCADA) system. From the perspective of overall network optimization, it adjusts the parameters of reactive power control equipment to achieve coordinated optimization and automatic closed-loop control of reactive power devices.

[0004] However, the AVC voltage regulation mode is based on the traditional unidirectional power flow characteristics and cannot automatically follow the real-time power flow changes of the power grid to make dynamic adjustments, thus becoming disconnected from the new characteristics of the distribution network of "source-load interaction". Secondly, it cannot adapt to the fluctuation of photovoltaic output with weather changes and is difficult to respond to voltage fluctuations caused by changes in sunlight. Thirdly, the voltage correspondence between the main grid and the distribution grid has changed from "the main grid is higher than the distribution grid" to dynamic changes, and the upper and lower limits of the bus voltage uniformly set by the AVC system cannot match this change, resulting in insufficient voltage regulation accuracy, which is ultimately not conducive to improving the level of power supply service. Summary of the Invention

[0005] This invention provides a voltage regulation method and device based on real-time power flow changes on the low-voltage side of the main transformer, in order to solve the voltage over-limit problem caused by bidirectional power flow in the power grid after a large number of distributed photovoltaic systems are connected.

[0006] In a first aspect, embodiments of the present invention provide a voltage regulation method based on real-time power flow changes on the low-voltage side of a main transformer, comprising: Real-time acquisition of power flow parameters on the low-voltage side of the main transformer; Based on the aforementioned current flow parameters, construct a current flow parameter curve; Set AVC policy limits; Based on the power flow parameter curve, determine a voltage regulation strategy suitable for bidirectional power flow scenarios; Based on the voltage regulation strategy and the AVC strategy limit, the reactive power regulation equipment associated with the low-voltage side of the main transformer is controlled to operate, thereby achieving voltage regulation.

[0007] In one possible implementation, the power flow parameters include active load and corresponding time; Based on the aforementioned tidal current parameters, a tidal current parameter curve is constructed, including: Based on the power flow parameters, an active load curve is determined with the horizontal axis representing time and the vertical axis representing active load.

[0008] In one possible implementation, a voltage regulation strategy adapted to a bidirectional power flow scenario is determined based on the power flow parameter curve, including: Based on the power flow parameter curve, determine the maximum active load before the preset time of the day, and set the AVC input voltage before the preset time as the bus voltage; The AVC input voltage is determined based on the active load after the preset time on that day and the maximum active load.

[0009] In one possible implementation, determining the AVC input voltage based on the active load after the preset time on the current day and the maximum active load includes: The active load after the preset time on the same day is compared with the maximum active load, and the AVC input voltage is determined based on the comparison result.

[0010] In one possible implementation, comparing the active load after the preset time on the current day with the maximum active load, and determining the AVC input voltage based on the comparison result, includes: If the active load after the preset time on the same day is less than the maximum active load, then the AVC input voltage is reduced based on the current AVC input voltage. If the active load after the preset time on the same day is greater than the maximum active load, then the AVC input voltage is increased based on the current AVC input voltage; If the active load after the preset time on the same day is equal to the maximum active load, then the current AVC input voltage is set to the bus voltage.

[0011] In one possible implementation, reducing the AVC input voltage based on the current AVC input voltage includes: according to Determine the AVC input voltage; in, Indicates the AVC input voltage. Indicates bus voltage. This represents the correction voltage, which is a positive number. Increasing the AVC input voltage based on the current AVC input voltage includes: according to Determine the AVC input voltage.

[0012] In one possible implementation, The determination method is as follows: set it to a fixed value, or determine it based on the difference between the active load after the preset time on the day and the maximum active load.

[0013] In one possible implementation, the preset time can be obtained in the following ways: Specify a fixed time; Alternatively, determine the turning point in the power flow parameter curve when the stable nighttime load is about to enter a downward trend.

[0014] Secondly, embodiments of the present invention provide a voltage regulation device based on real-time power flow changes on the low-voltage side of a main transformer, comprising: The acquisition module is used to acquire power flow parameters on the low-voltage side of the main transformer in real time. A construction module is used to construct a power flow parameter curve based on the power flow parameters; The processing module is used to set AVC policy limits; The processing module is also used to determine a voltage regulation strategy suitable for bidirectional tidal flow scenarios based on the tidal flow parameter curve. The control module is used to control the operation of the reactive power regulation equipment associated with the low-voltage side of the main transformer according to the voltage regulation strategy and the AVC strategy limit, so as to realize voltage regulation.

[0015] Thirdly, embodiments of the present invention provide a terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the voltage regulation method based on real-time power flow changes on the low-voltage side of the main transformer as described in the first aspect or any possible implementation of the first aspect.

[0016] This invention provides a voltage regulation method and apparatus based on real-time power flow changes on the low-voltage side of a main transformer. It collects power flow parameters from the low-voltage side of the main transformer in real time, constructs a power flow parameter curve based on these parameters, sets AVC (Automatic Power Controller) policy limits, determines a voltage regulation strategy suitable for bidirectional power flow scenarios based on the power flow parameter curve, and then controls the operation of reactive power regulation equipment associated with the low-voltage side of the main transformer based on the voltage regulation strategy and AVC policy limits, thereby achieving voltage regulation. This invention can sense power flow changes in the distribution network in real time, select an appropriate voltage regulation strategy, and precisely adjust reactive power equipment within the station based on the automatic voltage control system of the dispatch master station, effectively improving the voltage regulation level and thus solving the voltage limit exceeding problem caused by bidirectional power flow in the grid after a large number of distributed photovoltaic systems are connected. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the implementation of a voltage regulation device method based on real-time power flow changes on the low-voltage side of the main transformer, as provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of a 110kV substation provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the active power load curve provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a voltage regulation device based on real-time power flow changes on the low-voltage side of the main transformer, provided in an embodiment of the present invention. Figure 5 This is a schematic diagram of the terminal provided in an embodiment of the present invention. Detailed Implementation

[0019] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0021] Figure 1A flowchart illustrating the implementation of a voltage regulation method based on real-time power flow changes on the low-voltage side of a main transformer, provided in an embodiment of the present invention, is detailed below: Step 101: Real-time acquisition of power flow parameters on the low-voltage side of the main transformer.

[0022] See Figure 2 The diagram shows a 110kV substation with a large load and high photovoltaic back-feed. The two main transformers, #1 and #2, are operating separately, with switches 145, 345, and 545 all in the open position. Switches 101, 102, 301, 302, 501, and 502 on all three sides of the main transformer are in the closed position. Each main transformer carries half the load, i.e., main transformer #1 carries 35kV 5M and 10kV 4M, main transformer #2 carries 35kV 4M and 10kV 5M, bus #4 carries two outgoing lines 511 and 513, and bus #5 carries two outgoing lines 512 and 514.

[0023] Based on the aforementioned substation, power flow parameters at switch 502 on the low-voltage side of the main transformer were collected on a certain day.

[0024] Optionally, power flow parameters include active load and the time corresponding to the active load acquisition.

[0025] In a power system, active load refers to the power actually consumed in a circuit to perform useful work, usually measured in watts (W) or kilowatts (kW). It is the power actually consumed by electrical equipment during normal operation and can be directly converted into usable energy forms such as mechanical energy, heat energy, and light energy.

[0026] Optionally, power flow parameters of the substation SCADA system can be collected in real time. These parameters may include power flow direction, reactive power, voltage value, power factor, and load change rate.

[0027] Step 102: Construct the current flow parameter curve based on the current flow parameters.

[0028] Optionally, based on the power flow parameters, a power flow parameter curve can be constructed, which may include: determining an active power load curve with the horizontal axis representing time and the vertical axis representing active power load based on the power flow parameters.

[0029] See Figure 3 The active power load curve diagram shown is a curve diagram formed by connecting the active power corresponding to each 40-minute interval in 24 hours. When the active power load is greater than 0, it means that the active power flows from the load to the grid. When the active power load is less than 0, it means that the power flows from the grid to the load.

[0030] Optionally, before determining the voltage regulation strategy suitable for bidirectional power flow scenarios, it is first necessary to analyze the dynamic change characteristics of the power flow on the low-voltage side of the main transformer based on the power flow parameters, and then determine the voltage regulation strategy suitable for bidirectional power flow scenarios based on the analysis results.

[0031] See Figure 3 The active power load is analyzed by time period, as shown below: (1) 0:00-6:40: Nighttime work stoppage and production stoppage, active load trough period, and active load is relatively flat, power flows from the grid side to the load.

[0032] (2) 6:40-8:00 AM: People start their day's work and life. During this period, the light is not very good, the photovoltaic system generates little electricity, and the negative active load is relatively large. Power flows from the grid side to the load.

[0033] (3) 8:00: This is an inflection point. If there is no photovoltaic system at this time, the power flowing into the bus will become larger and larger, and the negative active load will become larger and larger. However, because there is a photovoltaic system, photovoltaic power generation begins, and the output is becoming larger and larger, and the active load begins to increase. Therefore, it turns upward, turning from negative to positive, and reaches its peak at noon.

[0034] (4) During the period from 8:00 to 10:00, the sunlight becomes stronger, and the photovoltaic system feeds back to offset the load demand. The absolute value of the power flowing into the bus on the low-voltage side of the main transformer becomes less and less, and reaches 0 before 10:00. Photovoltaic system feed-back means that the photovoltaic system generates enough power to support the load demand and there is a surplus, which flows back into the grid.

[0035] (5) During the period from 10:00 to 13:00, the power flows out from the low-voltage bus. The outflow bus is positive and the outflow value is getting larger and larger, indicating that the photovoltaic system is sending more and more power back towards noon. The power sent back reaches its peak around 13:00.

[0036] (6) During the period from 13:00 to 16:00, the photovoltaic system is still in the reverse transmission stage. The power flow flows out from the bus, but as the light weakens, the reverse transmission of the photovoltaic system becomes less and less until it is 0.

[0037] (7) During the period from 16:00 to 18:00, power flows from the main transformer into the bus. The flow into the bus is negative and the flow increases until it reaches an extreme value at around 18:10.

[0038] (8) During the period from 18:00 to 24:00, people stop working and their electricity demand decreases, so the power flowing into the bus is relatively reduced, but it still flows from the grid to the load.

[0039] In summary, the overall active power load can be divided into the following 5 stages: (1) 0:00-6:40, the nighttime load off-peak period; (2) 6:40-8:40, morning rush hour; (3) 8:40-16:40, photovoltaic back-transmission period; (4) 16:40-19:00, evening rush hour; (5) 19:00-24:00, the nighttime load is at its lowest point.

[0040] Regarding the five stages mentioned above, during the nighttime load off-peak period, load changes are relatively small, so the demand for voltage regulation is also small; during the morning peak period, active load is large and photovoltaic system power generation is low, so low voltage problems are prone to occur, requiring voltage increases, resulting in a large demand for voltage regulation; during the photovoltaic back-feeding period, especially during periods of large back-feeding, the distribution network becomes the "source," which is prone to high voltage problems, thus requiring voltage reduction, resulting in a large demand for voltage regulation; during the evening peak period, active load is large and photovoltaic system power generation is low, which is prone to low voltage problems, thus requiring voltage increases, resulting in a large demand for voltage regulation; during the nighttime load off-peak period, load changes are relatively small, so the demand for voltage regulation is also small.

[0041] Step 103: Set AVC policy limits.

[0042] Based on the above analysis, the voltage regulation requirement can be determined, and AVC voltage regulation can be performed based on the voltage regulation requirement.

[0043] AVC voltage regulation mainly involves two elements: AVC system input and AVC strategy settings.

[0044] The input to the AVC system is the bus voltage within the station, which serves as the AVC regulation criterion.

[0045] AVC strategy settings define the upper and lower limits of the input bus voltage. AVC strategy limits can include... , , Indicates the lower limit of voltage. This indicates the upper limit of the voltage. When the input bus voltage reaches the upper or lower limit of the policy limit, the system will determine that adjustment is required, and then issue control commands to the reactive power equipment to reduce or increase the voltage to meet user needs.

[0046] Optionally, the AVC strategy limits can be dynamically set based on the rated voltage of the low-voltage side of the main transformer: the upper limit threshold is 1.07 times the rated voltage, and the lower limit threshold is 0.93 times the rated voltage, and the thresholds can be remotely adjusted according to grid dispatch instructions. For example, the AVC strategy limits can be 10.1kV-10.5kV.

[0047] Step 104: Determine the voltage regulation strategy suitable for bidirectional power flow scenarios based on the power flow parameter curve.

[0048] Based on the above five stages, when there is a need to increase the voltage, the input of the AVC system is reduced, so that the input voltage reaches the lower limit of the AVC strategy earlier and responds to the boost demand more quickly; when there is a need to decrease the voltage, the input of the AVC system is increased, so that the input voltage reaches the upper limit of the AVC strategy earlier and responds to the buck demand more quickly.

[0049] Optionally, (1) During the period from 0:00 to 6:40, the active load changes less and the voltage regulation requirement is less. The AVC input voltage can be directly set to the bus voltage without any adjustment.

[0050] (2) During the period from 6:40 to 8:40, the active load is relatively large and the load changes significantly, resulting in a greater demand for voltage regulation and a need to raise the voltage. Therefore, the AVC input is adjusted as follows: This means reducing the AVC input voltage value at this time, so that it can reach the lower limit of the AVC strategy more quickly and boost the voltage to meet the regulation requirements more quickly. Indicates the AVC input voltage. This indicates the bus voltage.

[0051] (3) During the period from 8:40 to 16:40, this is the period of reverse transmission of the photovoltaic system, and the demand for voltage regulation is relatively large. It is necessary to reduce the voltage and adjust the AVC input as follows: This means raising the AVC input voltage value at this time, so that it can reach the upper limit of the AVC strategy more quickly and respond to the buck regulation demand more quickly.

[0052] (4) During the period from 16:40 to 19:00, the load is relatively large and the load changes significantly, resulting in a greater demand for voltage regulation. Therefore, it is necessary to raise the voltage and adjust the AVC input as follows: This means reducing the AVC input voltage value at this time, so that it can reach the lower limit of the AVC strategy more quickly and respond to the boost regulation demand more quickly.

[0053] (5) During the period from 19:00 to 24:00, the load changes are small and the voltage regulation demand is small. The AVC input voltage is set to the bus voltage and no adjustment is made.

[0054] However, in practice, due to the seasonality of active power load changes and their variation with weather, it is impractical to implement the above settings precisely for each day and time period. Therefore, in this embodiment, different AVC input data are selected according to requirements. In one embodiment, a voltage regulation strategy adapted to the bidirectional power flow scenario is determined based on the power flow parameter curve, which may include: Based on the power flow parameter curve, determine the maximum active load before the preset time of the day, and set the AVC input voltage before the preset time as the bus voltage; The AVC input voltage is determined based on the active load and maximum active load after the preset time of the day.

[0055] Optionally, the preset time can be obtained by: specifying a fixed time; or determining the turning point in the power flow parameter curve when the nighttime stable load is about to enter a downward trend.

[0056] The above analysis shows that the active power load curve reverses at 6:00 AM. Therefore, the maximum load before 6:00 AM can be taken as the maximum active power load. Since the timing of the reversal in the active power load curve may vary depending on the season, the exact time of 6:00 AM can be adjusted according to the season. The time when the power flow parameter curve (i.e., the active power load curve) is approximately when it is about to decline in the morning can be selected; that is, the turning point in the power flow parameter curve where the stable nighttime load is about to enter a downward trend.

[0057] In one embodiment, determining the AVC input voltage based on the active load after a preset time on the day and the maximum active load may include: comparing the active load after the preset time on the day with the maximum active load, and determining the AVC input voltage based on the comparison result. That is, comparing the active load after 6:00 with the maximum active load, and determining the AVC input voltage based on the comparison result.

[0058] In one embodiment, the active load after a preset time on the day is compared with the maximum active load, and the AVC input voltage is determined based on the comparison result, including: If the active load after the preset time on the day is less than the maximum active load, the photovoltaic system will not generate electricity or generate less electricity. The smaller the active load, the greater the demand for voltage boost. In order to respond to the demand for voltage boost more quickly, the AVC input voltage will be reduced based on the current AVC input voltage. If the active load after the preset time on the day is greater than the maximum active load, the photovoltaic system has started to feed back and has a certain scale. The larger the active load, the greater the demand for voltage reduction. Therefore, the AVC input voltage will be increased based on the current AVC input voltage. If the active load after the preset time on the day is equal to the maximum active load, then the current AVC input voltage will be set to the bus voltage.

[0059] Optionally, the AVC input voltage can be reduced from the current AVC input voltage, including: according to Determine the AVC input voltage; in, Indicates the AVC input voltage. Indicates bus voltage. This represents the correction voltage, which is a positive number; here, because the current AVC input voltage is set to the bus voltage before the preset time of the day, therefore... It can also refer to the current AVC input voltage.

[0060] Then, based on the current AVC input voltage, the AVC input voltage is increased, including: according to Determine the AVC input voltage.

[0061] In one embodiment, The determination method is as follows: set it to a fixed value, such as 0.1kV, or determine it based on the difference between the active load after the preset time of the day and the maximum active load.

[0062] On cloudy days, the situation is similar to that of a substation without photovoltaic access. For most of the day, the load is less than the maximum load between 0:00 and 6:00 (the electricity demand between 0:00 and 6:00 is relatively small), so there is a greater need to raise the voltage. The voltage regulation strategy provided in step 104 is applicable.

[0063] The voltage regulation method described above can track the power flow changes of the main transformer in real time and dynamically adjust the input voltage of the AVC system according to the power flow. It can accurately reflect power flow changes not only in normal weather but also in cloudy weather. When there is a need to increase the voltage, the AVC system input is reduced so that the AVC input voltage reaches the strategy lower limit earlier and responds to the boost demand more quickly. When there is a need to decrease the voltage, the AVC system input is increased so that the AVC input voltage reaches the strategy upper limit earlier and responds to the buck demand more quickly.

[0064] Step 105: Based on the voltage regulation strategy and AVC strategy limits, control the operation of the reactive power regulation equipment associated with the low-voltage side of the main transformer to achieve voltage regulation.

[0065] By adjusting the voltage input, the AVC system can reach the upper and lower limits of the strategy more quickly, issue control commands to the reactive power equipment, and make the reactive power equipment act more promptly.

[0066] Optionally, the AVC system can collect key electrical quantities of the low-voltage side bus of the main transformer in real time, such as voltage, reactive power, and the status of reactive power regulation equipment. By comparing the real-time voltage with the AVC strategy limits, it determines whether the voltage exceeds the limit. When the real-time voltage is greater than the upper limit, the voltage is too high and needs to be reduced; when the real-time voltage is less than the lower limit, the voltage is too low and needs to be increased; when the real-time voltage is greater than the lower limit but less than the upper limit, the voltage is normal and the current state can be maintained.

[0067] The reactive power regulation equipment associated with the low-voltage side of the main transformer mainly includes capacitor banks, reactors, and static var generators (SVG). The operating logic follows the principle of combining priority and tiered regulation. 1. When the voltage is too low, prioritize switching on the capacitor bank before starting the SVG.

[0068] Capacitor banks are discrete control devices, switching on and off as a whole, which is low-cost and highly reliable. They are switched on "from few to many," for example, starting with one capacitor bank and switching on the next bank if the voltage is still low, until the voltage returns to the normal range or all capacitors are switched on.

[0069] If the voltage is still insufficient after all capacitors are connected, such as in extreme scenarios like sudden load changes or photovoltaic backfeeding, the SVG can precisely compensate for the shortfall by continuously adjusting the output capacitive reactive power.

[0070] 2. When the voltage is too high, prioritize disconnecting the capacitor bank before switching on the reactor or SVG.

[0071] First, disconnect the capacitor banks that are already in operation to reduce reactive power injection and lower the voltage.

[0072] If the voltage remains high after the capacitor bank is fully disconnected, such as when the load is extremely light late at night and the photovoltaic backflow is strong, then the reactor or SVG should be put into operation to forcibly lower the voltage.

[0073] It should be noted that when switching capacitors and reactors, a minimum switching interval must be set to prevent frequent switching from shortening their lifespan; the switching interval can be set to any time between 5 minutes and 10 minutes.

[0074] The following example illustrates the automation implementation process. Set the SCADA telemetry operation numbers as follows: @1, @2, @3, @4, @5, where @1 is the maximum load from 0:00:00 to 6:00:00; @2 is the active load on the low-voltage side of the main transformer from 6:00:01 to 23:59:59; @3 is the AVC system input; @4 is the bus voltage read in real time by the SCADA system; and @5 is the bus voltage correction value. The implementation process is as follows: @1=max P (0:00:00-6:00:00), where P represents the active load before 6:00:00 on the current day; @2=P(6:00:01-23:59:59) @3= ; @4 = (Bus voltage); @5 is the correction value; Then, if @2 < @1, then @3 = @4 - @5; If @2 > @1, then @3 = @4 + @5; If @2=@1, @3=@4; @5>0.

[0075] This invention provides a voltage regulation method based on real-time power flow changes on the low-voltage side of a main transformer. It involves real-time acquisition of power flow parameters on the low-voltage side of the main transformer, constructing a power flow parameter curve based on these parameters, setting AVC (Automatic Power Controller) policy limits, determining a voltage regulation strategy suitable for bidirectional power flow scenarios based on the power flow parameter curve, and then controlling the operation of reactive power regulation equipment associated with the low-voltage side of the main transformer based on the voltage regulation strategy and AVC policy limits to achieve voltage regulation. This invention can sense real-time power flow changes in the distribution network, select an appropriate voltage regulation strategy, and precisely adjust reactive power equipment within the station based on the automatic voltage control system of the dispatch master station, effectively improving voltage regulation levels and thus solving the voltage limit exceeding problem caused by bidirectional power flow in the grid after a large number of distributed photovoltaic systems are connected.

[0076] This invention dynamically adjusts the AVC system input voltage in real time according to power flow changes, accurately reflecting power flow. When there is a need to increase the voltage, the AVC system input is reduced, allowing the input voltage to reach the policy lower limit earlier and respond to the boost demand more quickly. When there is a need to decrease the voltage, the AVC system input is increased, allowing the input voltage to reach the policy upper limit earlier and respond to the buck demand more quickly. After the AVC system reaches the policy upper and lower limits more quickly, it issues control commands to the reactive power equipment, making the reactive power equipment operate more promptly.

[0077] The voltage regulation method based on real-time power flow changes on the low-voltage side of the main transformer provided in this invention is widely applicable to full-scale substations, including those without photovoltaic power and those with extensive photovoltaic integration.

[0078] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0079] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0080] Figure 4 The diagram illustrates a voltage regulation device based on real-time power flow changes on the low-voltage side of a main transformer, according to an embodiment of the present invention. For ease of explanation, only the parts relevant to the embodiment are shown, and are detailed below: like Figure 4 As shown, the voltage regulation device 4 based on real-time power flow changes on the low-voltage side of the main transformer includes: a data acquisition module 41, a data construction module 42, a processing module 43, and a control module 44.

[0081] Acquisition module 41 is used to acquire power flow parameters on the low-voltage side of the main transformer in real time; Module 42 is used to construct the power flow parameter curve based on the power flow parameters; Processing module 43 is used to set AVC policy limits; The processing module 43 is also used to determine a voltage regulation strategy that is suitable for bidirectional power flow scenarios based on the power flow parameter curve. The control module 44 is used to control the operation of the reactive power regulation equipment associated with the low-voltage side of the main transformer according to the voltage regulation strategy and AVC strategy limit, so as to realize voltage regulation.

[0082] In one possible implementation, the power flow parameters include active load and the corresponding time; When building the power flow parameter curve based on the power flow parameters, module 42 is used for: Based on the power flow parameters, an active load curve is determined, with the horizontal axis representing time and the vertical axis representing active load.

[0083] In one possible implementation, when processing module 43 determines a voltage regulation strategy suitable for a bidirectional power flow scenario based on the power flow parameter curve, it is used to: Based on the power flow parameter curve, determine the maximum active load before the preset time of the day, and set the AVC input voltage before the preset time as the bus voltage; The AVC input voltage is determined based on the active load and maximum active load after the preset time of the day.

[0084] In one possible implementation, when processing module 43 determines the AVC input voltage based on the active load and maximum active load after a preset time on the day, it is used to: The active load after the preset time of the day is compared with the maximum active load, and the AVC input voltage is determined based on the comparison result.

[0085] In one possible implementation, the processing module 43 compares the active load after a preset time on the current day with the maximum active load, and when determining the AVC input voltage based on the comparison result, it is used for: If the active load after the preset time on the day is less than the maximum active load, then the AVC input voltage will be reduced based on the current AVC input voltage. If the active load after the preset time of the day is greater than the maximum active load, then the AVC input voltage will be increased based on the current AVC input voltage. If the active load after the preset time on the day is equal to the maximum active load, then the current AVC input voltage will be set to the bus voltage.

[0086] In one possible implementation, when processing module 43 reduces the AVC input voltage based on the current AVC input voltage, it is used to: according to Determine the AVC input voltage; in, Indicates the AVC input voltage. This indicates the bus voltage or the current AVC input voltage. This represents the correction voltage, which is a positive number. Processing module 43, when increasing the AVC input voltage based on the current AVC input voltage, is used for: according to Determine the AVC input voltage.

[0087] In one possible implementation, The determination method is either to set it to a fixed value, or to determine it based on the difference between the active load after the preset time of the day and the maximum active load.

[0088] In one possible implementation, the preset time can be obtained in the following ways: Specify a fixed time; Alternatively, determine the turning point in the power flow parameter curve when the stable nighttime load is about to begin a downward trend.

[0089] The aforementioned voltage regulation device based on real-time power flow changes on the low-voltage side of the main transformer collects power flow parameters from the low-voltage side of the main transformer in real time through an acquisition module. Then, a construction module constructs a power flow parameter curve based on these parameters. A processing module sets AVC (Automatic Power Controller) policy limits and determines a voltage regulation strategy suitable for bidirectional power flow scenarios based on the power flow parameter curve. Finally, based on the voltage regulation strategy and AVC policy limits, a control module controls the reactive power regulation equipment associated with the low-voltage side of the main transformer to achieve voltage regulation. This embodiment of the invention can sense real-time power flow changes in the distribution network, select an appropriate voltage regulation strategy, and precisely adjust reactive power equipment within the station based on the automatic voltage control system of the dispatch master station, effectively improving the voltage regulation level and thus solving the voltage limit exceeding problem caused by bidirectional power flow in the grid after a large number of distributed photovoltaic systems are connected.

[0090] This invention dynamically adjusts the AVC system input voltage in real time according to power flow changes, accurately reflecting power flow. When there is a need to increase the voltage, the AVC system input is reduced, allowing the input voltage to reach the policy lower limit earlier and respond to the boost demand more quickly. When there is a need to decrease the voltage, the AVC system input is increased, allowing the input voltage to reach the policy upper limit earlier and respond to the buck demand more quickly. After the AVC system reaches the policy upper and lower limits more quickly, it issues control commands to the reactive power equipment, making the reactive power equipment operate more promptly.

[0091] Figure 5 This is a schematic diagram of a terminal provided in an embodiment of the present invention. Figure 5As shown, the terminal 5 in this embodiment includes: a processor 50, a memory 51, and a computer program 52 stored in the memory 51 and executable on the processor 50. When the processor 50 executes the computer program 52, it implements the steps in the various embodiments of the voltage regulation method based on real-time power flow changes on the low-voltage side of the main transformer, for example... Figure 1 Steps 101 to 105 are shown. Alternatively, when the processor 50 executes the computer program 52, it implements the functions of each module / unit in the above-described device embodiments, for example... Figure 4 The functions of each module / unit are shown.

[0092] For example, the computer program 52 can be divided into one or more modules / units, which are stored in the memory 51 and executed by the processor 50 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 52 in the terminal 5. For example, the computer program 52 can be divided into... Figure 4 The modules / units shown are shown.

[0093] The terminal 5 may include, but is not limited to, a processor 50 and a memory 51. Those skilled in the art will understand that... Figure 5 This is merely an example of terminal 5 and does not constitute a limitation on terminal 5. It may include more or fewer components than shown, or combine certain components, or different components. For example, the terminal may also include input / output devices, network access devices, buses, etc.

[0094] The processor 50 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0095] The memory 51 can be an internal storage unit of the terminal 5, such as a hard disk or memory of the terminal 5. The memory 51 can also be an external storage device of the terminal 5, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the terminal 5. Furthermore, the memory 51 can include both internal storage units and external storage devices of the terminal 5. The memory 51 is used to store the computer program and other programs and data required by the terminal. The memory 51 can also be used to temporarily store data that has been output or will be output.

[0096] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0097] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0098] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0099] In the embodiments provided by this invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0100] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0101] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0102] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium. When executed by a processor, the computer program can implement the steps of the above-described voltage regulation method embodiments based on real-time power flow changes on the low-voltage side of the main transformer. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0103] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A voltage regulation method based on real-time power flow changes on the low voltage side of a main transformer, characterized by, include: Real-time acquisition of power flow parameters on the low-voltage side of the main transformer; Based on the aforementioned current flow parameters, construct a current flow parameter curve; Set AVC policy limits; Based on the power flow parameter curve, determine a voltage regulation strategy suitable for bidirectional power flow scenarios; Based on the voltage regulation strategy and the AVC strategy limit, the reactive power regulation equipment associated with the low-voltage side of the main transformer is controlled to operate, thereby achieving voltage regulation.

2. The voltage regulation method based on real-time power flow changes on the low-voltage side of the main transformer according to claim 1, characterized in that, The power flow parameters include active load and corresponding time; Based on the aforementioned tidal current parameters, a tidal current parameter curve is constructed, including: Based on the power flow parameters, an active load curve is determined with the horizontal axis representing time and the vertical axis representing active load.

3. The voltage regulation method based on real-time power flow changes on the low-voltage side of the main transformer according to claim 2, characterized in that, Based on the power flow parameter curve, a voltage regulation strategy suitable for bidirectional power flow scenarios is determined, including: Based on the power flow parameter curve, determine the maximum active load before the preset time of the day, and set the AVC input voltage before the preset time as the bus voltage; The AVC input voltage is determined based on the active load after the preset time on that day and the maximum active load.

4. The voltage regulation method based on real-time power flow changes on the low-voltage side of the main transformer according to claim 3, characterized in that, The step of determining the AVC input voltage based on the active load after the preset time on that day and the maximum active load includes: The active load after the preset time on the same day is compared with the maximum active load, and the AVC input voltage is determined based on the comparison result.

5. The voltage regulation method based on real-time power flow changes on the low-voltage side of the main transformer according to claim 4, characterized in that, The step of comparing the active load after the preset time on the current day with the maximum active load, and determining the AVC input voltage based on the comparison result, includes: If the active load after the preset time on the same day is less than the maximum active load, then the AVC input voltage is reduced based on the current AVC input voltage. If the active load after the preset time on the same day is greater than the maximum active load, then the AVC input voltage is increased based on the current AVC input voltage; If the active load after the preset time on the same day is equal to the maximum active load, then the current AVC input voltage is set to the bus voltage.

6. The voltage regulation method based on real-time power flow changes on the low-voltage side of the main transformer according to claim 5, characterized in that, Then, based on the current AVC input voltage, the AVC input voltage is reduced, including: according to Determine the AVC input voltage; in, Indicates the AVC input voltage. Indicates bus voltage. This represents the correction voltage, which is a positive number. Increasing the AVC input voltage based on the current AVC input voltage includes: according to Determine the AVC input voltage.

7. The voltage regulation method based on real-time power flow changes on the low-voltage side of the main transformer according to claim 6, characterized in that, The determination method is as follows: set it to a fixed value, or determine it based on the difference between the active load after the preset time on the day and the maximum active load.

8. The voltage regulation method based on real-time power flow changes on the low-voltage side of the main transformer according to any one of claims 3-7, characterized in that, The methods for obtaining the preset time include: Specify a fixed time; Alternatively, determine the turning point in the power flow parameter curve when the stable nighttime load is about to enter a downward trend.

9. A voltage regulation device based on real-time power flow changes on the low-voltage side of a main transformer, characterized in that, include: The acquisition module is used to acquire power flow parameters on the low-voltage side of the main transformer in real time. A construction module is used to construct a power flow parameter curve based on the power flow parameters; The processing module is used to set AVC policy limits; The processing module is also used to determine a voltage regulation strategy suitable for bidirectional tidal flow scenarios based on the tidal flow parameter curve. The control module is used to control the operation of the reactive power regulation equipment associated with the low-voltage side of the main transformer according to the voltage regulation strategy and the AVC strategy limit, so as to realize voltage regulation.

10. A terminal, comprising a memory and a processor, the memory for storing a computer program, the processor for calling and running the computer program stored in the memory, characterized in that, When the processor executes the computer program, it implements the steps of the voltage regulation method based on real-time power flow changes on the low-voltage side of the main transformer as described in any one of claims 1 to 8.

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