Low-voltage terminal phase separation bidirectional adaptive voltage regulating system

Abstract

The application relates to the field of low-voltage distribution network voltage regulation and power quality control, and discloses a low-voltage terminal phase-separated bidirectional adaptive voltage regulating system; the system comprises phase-separated voltage regulating units, collecting units and a controller which are respectively arranged on A-phase, B-phase and C-phase lines. The controller establishes a non-regulating reference response relationship for each phase, determines directional gear migration after a voltage trigger regulating condition is generated at the load side, and forms stable observation data before and after regulating; according to line current changes and voltage stable state, it is judged whether the action result can be attributed, when the attribution condition is met, the load side reference voltage under the condition that the gear migration is not executed this time is determined in combination with the non-regulating reference response relationship, and the net regulating effect of the gear migration this time is obtained according to the load side reference voltage; according to the direction and size of the net regulating effect, effective response records or limited migration records are formed, and the target gear selection path is adjusted under the same subsequent operation condition.

Description

Technical Field

[0001] This invention relates to the field of voltage regulation and power quality control in low-voltage distribution networks, and specifically to a phase-by-phase adaptive voltage regulation system at the end of a low-voltage distribution area. Background Technology

[0002] As the power supply radius of rural distribution networks and low-voltage distribution areas continues to extend, some end-users are prone to experiencing low or fluctuating voltage due to factors such as long power line distances, small conductor cross-sectional areas, and concentrated power loads. Simultaneously, in distribution areas with distributed photovoltaic (PV) systems, localized voltage increases may occur due to variations in PV output. Existing voltage management methods for low-voltage distribution areas mainly include line upgrades, the addition of distribution transformers, reactive power compensation, and the installation of voltage regulating devices at the line ends. Among these, end-point voltage regulating devices typically adjust the voltage by switching different transformer ratios to boost, bypass, or reduce the voltage based on the relationship between the load-side voltage and set upper and lower limits, thereby restoring the load-side voltage to the allowable range. For low-voltage lines with unbalanced three-phase loads, phase-by-phase voltage regulation can also be used, allowing each phase to independently select its voltage regulation level based on its own voltage condition.

[0003] However, in actual operation of low-voltage distribution areas, the load-side voltage is not only affected by the voltage regulation setting, but also changes synchronously with the source-side voltage and line current. Especially in scenarios involving long-distance, high-impedance lines and frequent start-stop operations of loads such as pumping equipment, air conditioners, and electric heaters, changes in either the source-side voltage or the line current may occur simultaneously before and after the voltage regulation setting. If the effect of a particular voltage regulation setting is judged directly based on the difference in load-side voltage before and after the setting, it is difficult to distinguish between voltage changes caused by the setting switch and those caused by natural changes in line operating conditions. For example, when a voltage increase is performed while the source-side voltage decreases or the user load increases, the actual load-side voltage may increase only slightly, or even continue to decrease; conversely, when the source-side voltage itself increases or some load is removed, the voltage increase after the setting may be significantly larger. Therefore, evaluating the voltage regulation effect solely based on voltage changes before and after the setting can easily lead to misjudgments of the actual effect of the setting.

[0004] When the voltage regulating device selects subsequent voltage levels or makes adaptive adjustments based on the aforementioned voltage adjustment results, if it fails to first determine whether the operating data before and after the voltage adjustment is comparable, and fails to distinguish the impact of changes in source-side voltage and line current on load-side voltage from the actual voltage adjustment action, an abnormal result caused by load start-up / shutdown or source-side fluctuations may be incorrectly recorded as a valid or invalid response for a certain voltage level, leading to repeated inappropriate voltage increase or decrease operations under similar operating conditions. Especially for low-voltage distribution areas with independent voltage regulation for each phase, unreasonable single-phase voltage selection may further amplify the differences between phase voltages. Therefore, accurately identifying the actual voltage regulation effect generated by a single voltage level shift when source-side voltage, line current, and load-side voltage all change with operating conditions, and accordingly rationally adjusting subsequent voltage level shift paths, remains a problem that needs to be solved in the existing adaptive voltage regulation process at the end of low-voltage distribution areas. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a low-voltage distribution area terminal phase-separated bidirectional adaptive voltage regulation system to solve the technical problems existing in the prior art.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A low-voltage distribution area terminal phase-separated bidirectional adaptive voltage regulation system includes phase-separated voltage regulation units, acquisition units, and controllers connected to the phase-separated voltage regulation units and acquisition units respectively installed on the A-phase, B-phase, and C-phase lines. The phase-separated voltage regulation units have boosting, bypass, and deboosting levels, and each phase-separated voltage regulation unit can switch levels independently. The acquisition unit acquires the source-side voltage at the input side of each phase-by-phase voltage regulation unit, the load-side voltage at the output side, and the line current of the corresponding phase. The controller establishes a no-adjustment reference response relationship for each phase. The no-adjustment reference response relationship is formed by the stable operating section during which the phase-by-phase voltage regulation unit of the corresponding phase maintains the same level and no level switching occurs. It is used to characterize the correspondence between source-side voltage change, line current change and load-side voltage change. When the load-side voltage of any phase triggers the voltage regulation condition, the controller determines the directed shift of that phase from the current shift to the target shift. Before the directed shift is executed, the first stable observation data is generated, and after the shift is switched, the second stable observation data is generated. Both the first and second stable observation data include the source-side voltage, the load-side voltage, and the line current. Based on the line current change between the first and second stable observation data and the voltage stability state corresponding to the two sets of stable observation data, the controller determines whether the directed gear shift meets the attributable conditions of the action result. When the conditions for attributable action results are met, the controller determines the load-side reference voltage under the condition that the directed shift was not performed, based on the no-shift reference response relationship, source-side voltage change and line current change; and determines the net voltage regulation effect of the directed shift based on the deviation between the actual load-side voltage and the load-side reference voltage in the second stability observation data. When the direction of the net pressure regulation is consistent with the direction of the current directional gear shift, and the absolute value of the net pressure regulation reaches the effective response threshold, the target gear is maintained and an effective response record is formed. When the direction of the net voltage regulation is inconsistent with the direction of the voltage regulation during this directional shift, or when the absolute value of the net voltage regulation does not reach the effective response threshold, the corresponding phase is controlled to return to the shift position before the shift, and the current directional shift is associated with the operating conditions when the directional shift is performed to form a restricted shift record; the operating conditions are determined by the source-side voltage range and line current range of the corresponding phase. When the controller subsequently meets the operating conditions associated with the restricted migration record, it determines the target gear for the corresponding phase after excluding the directed gear migration corresponding to the restricted migration record.

[0007] Preferably, each phase voltage regulating unit includes an autotransformer, a tap-switching circuit, and a bypass circuit; The autotransformer has taps with different turns ratios; the gear switching circuit is connected to the taps respectively, and selects the corresponding tap according to the gear control signal output by the controller to form a boost gear or a buck gear. The bypass circuit is connected between the input and output sides of the phase-splitting voltage regulating unit and is turned on in the bypass position; The acquisition unit includes source-side voltage sampling points, load-side voltage sampling points, and line current sampling points; the source-side voltage sampling points and load-side voltage sampling points are respectively set on the input side and output side of the phase-by-phase voltage regulation unit, and the line current sampling points are set on the corresponding phase lines.

[0008] Preferably, the controller divides the continuously collected source-side voltage, load-side voltage, and line current into observation periods with the same time length, and determines the average value and fluctuation range of the source-side voltage, load-side voltage, and line current in each observation period. The fluctuation range is the difference between the maximum and minimum values ​​of the corresponding data collected within the same observation period; When the fluctuation range of the source-side voltage does not exceed the source-side voltage stability threshold, the fluctuation range of the load-side voltage does not exceed the load-side voltage stability threshold, and the fluctuation range of the line current does not exceed the current stability threshold, the corresponding observation period is determined as the stable operation section. Stable observation data are formed using the average source-side voltage, average load-side voltage, and average line current within the stable operating section. Before performing a directed gear shift, the first stable observation data is formed from the stable operating section under the current gear; after the gear shift is completed, the second stable observation data is formed from the first observation period that meets the criteria for a stable operating section.

[0009] Preferably, the controller obtains at least three stable operating segments arranged in chronological order during the period when the corresponding phases remain in the same gear and no gear switching occurs, and forms a differential segment group with two stable operating segments that are adjacent in time. For each differential segment group, the average value of the previous stable operating segment is subtracted from the average value of the next stable operating segment to obtain the source-side voltage change, line current change, and load-side voltage change, respectively. Using the source-side voltage change and line current change as input quantities, and the load-side voltage change as response quantity, determine the source-side voltage change coefficient and the line current change coefficient. The source-side voltage variation coefficient and the line current variation coefficient minimize the sum of squared errors between the calculated load-side voltage variation and the measured load-side voltage variation. The source-side voltage variation coefficient and the line current variation coefficient constitute the reference response relationship without adjustment for the corresponding phase and the corresponding tap.

[0010] Preferably, the voltage regulation conditions are determined by the lower voltage threshold and the upper voltage threshold of the target voltage range; When the load-side voltage of the corresponding phase is lower than the lower voltage threshold and continues to exceed the voltage limit confirmation time, the controller determines the target level along the voltage boost direction; When the load-side voltage of the corresponding phase is higher than the upper voltage threshold and continues to exceed the voltage limit confirmation time, the controller determines the target level along the step-down direction; When the load-side voltage of the corresponding phase is within the target voltage range, maintain the current setting; When determining the target gear along the direction of pressure increase or decrease, the gears located in the corresponding pressure adjustment direction are arranged in ascending order of pressure adjustment increment relative to the current gear, and the first gear that has not been eliminated in the corresponding directional gear migration is determined as the target gear. When there is no unremoved directional gear shift in the corresponding pressure regulation direction, maintain the current gear.

[0011] Preferably, the conditions for attributing the action result include: the observation periods for forming the first stable observation data and the second stable observation data both meet the conditions for determining the stable operating section, and the absolute value of the difference between the line current in the first stable observation data and the second stable observation data does not exceed the current change limit. If any of the above conditions are not met, this directed gear shift will be determined as an action that cannot be attributed to a cause. For actions not attributable to the controller, the controller maintains the gear position after the gear shift until subsequent stable observation data is generated. It does not generate a valid response record or a restricted migration record based on this directed gear shift, and re-determines whether to trigger the voltage regulation condition based on subsequent stable observation data.

[0012] Preferably, for directed gear shifts that meet the attributable conditions of the action result, the controller subtracts the source-side voltage from the source-side voltage in the first stable observation data from the source-side voltage in the second stable observation data to obtain the source-side voltage change; and subtracts the line current from the line current in the first stable observation data from the line current in the second stable observation data to obtain the line current change. The load-side reference voltage is obtained by adding the product of the source-side voltage change and the source-side voltage change coefficient, the product of the line current change and the line current change coefficient, and the load-side voltage in the first stable observation data, without the execution of this directional tap migration. The difference between the actual load-side voltage and the load-side reference voltage in the second stable observation data is determined as the net voltage regulation effect; When the net pressure regulation effect is positive, it means that the current directed gear shift produces a pressure increase effect compared to the state before the directed gear shift was performed; when the net pressure regulation effect is negative, it means that the current directed gear shift produces a pressure decrease effect compared to the state before the directed gear shift was performed. Each gear has a rated voltage adjustment amount, which is the change in output voltage generated by the corresponding gear relative to the bypass gear under the rated input voltage. The effective response threshold is the product of the absolute value of the difference between the rated voltage adjustment of the gear before migration and the target gear, and the effective proportional coefficient, where the effective proportional coefficient is greater than 0 and less than 1.

[0013] Preferably, the restricted migration record includes the phase, the tap position before migration, the target tap position, and the source-side voltage range and line current range of the associated operating conditions; The source-side voltage range is centered on the source-side voltage at the time when the first stable observation data is formed, and the source-side voltage condition tolerance is half-width; the line current range is centered on the line current at the time when the first stable observation data is formed, and the line current condition tolerance is half-width; both the source-side voltage condition tolerance and the line current condition tolerance are positive values. During subsequent pressure regulation, the current operating conditions will be determined based on the most recently formed stable observation data; When the phase to be regulated is consistent with the phase, the current tap is consistent with the tap before migration, and the source-side voltage and line current in the recently formed stable observation data fall into the source-side voltage range and the line current range respectively, it is determined that the current operating condition meets the operating condition associated with the restricted migration record. The controller excludes directed gear migrations from the previous gear to the target gear, and retains directed gear migrations from the previous gear to other gears that are not excluded from restricted migration records under the current operating conditions.

[0014] Preferably, when the continuously generated stable observation data does not meet the operating conditions associated with the restricted migration record, and the duration reaches the recovery observation time, the controller converts the directed gear migration corresponding to the restricted migration record into a verification-allowed state. When the subsequent pressure regulation conditions point to a directed gear shift again, a verification gear shift is performed, and it is determined whether the verification gear shift meets the attributable conditions of the action result. When the confirmatory gear shift does not meet the attributable conditions for the action result, the corresponding phase is restored to the gear before the confirmatory gear shift, and the restricted shift record is retained. When the confirmatory gear shift meets the attributable conditions for the action result, the net pressure regulation effect of the confirmatory gear shift is determined based on the response relationship without gear shifting baseline. When the direction of the net voltage regulation is consistent with the direction of the voltage regulation of the confirmatory gear shift, and the absolute value of the net voltage regulation reaches the effective response threshold, the corresponding restricted migration record is released and an effective response record is formed. When the direction of the net voltage regulation is inconsistent with the direction of the voltage regulation during the confirmatory gear shift, or when the absolute value of the net voltage regulation does not reach the effective response threshold, the corresponding phase is restored to the gear before the confirmatory gear shift, and the restricted shift record is retained.

[0015] Preferably, the effective response record includes the corresponding directional tap shift, net voltage regulation effect, and the source-side voltage range and line current range when the effective response record is formed; The source-side voltage range is centered on the source-side voltage at the time when the first stable observation data is formed, and the source-side voltage condition tolerance is half-width; the line current range is centered on the line current at the time when the first stable observation data is formed, and the line current condition tolerance is half-width. For candidate directional tap shift, the controller obtains the corresponding net voltage regulation effect from the effective response records of the source-side voltage and line current in the source-side voltage range and line current range, respectively, which contain the most recently formed stable observation data. When there are more than two effective response records, the average value of the net voltage regulation effect in each effective response record is used as the candidate effective response. The controller adds the current load-side voltage of the corresponding phase to the candidate valid response to determine the candidate load-side voltage after migrating to the candidate target level; The candidate load-side voltage and the current load-side voltage of the other two phases are combined to form a three-phase candidate voltage group, and the difference between the maximum and minimum phase voltage in the three-phase candidate voltage group is determined as the phase-to-phase voltage discrete quantity. When the phase-to-phase voltage dispersion does not exceed the phase-to-phase voltage difference limit, perform candidate directed gear shifting. When the phase-to-phase voltage dispersion exceeds the phase-to-phase voltage difference limit, the current candidate directional gear shift is excluded, and the candidate target gear is re-determined from the remaining candidate directional gear shifts in the same voltage regulation direction in ascending order of voltage regulation increment relative to the current gear. If there are no other candidate gear shifts that meet the current operating conditions and have valid response records, maintain the current gear.

[0016] In summary, the present invention has the following main beneficial effects: This application establishes a non-adjustment reference response relationship for phases A, B, and C respectively, and uses stable operating data generated during the period when the corresponding phases maintain the same position and no position switching occurs to characterize the correspondence between source-side voltage changes, line current changes, and load-side voltage changes. After the actual execution of directed position shifting, the load-side reference voltage is determined by combining the stable observation data before and after the shifting, and the actual load-side voltage is compared with the load-side reference voltage to obtain the net voltage regulation effect generated by the directed position shifting itself. This achieves the effect of distinguishing the influence of natural fluctuations in source-side voltage and changes in line current on load-side voltage from the actual shifting effect, reducing the situation where natural line changes are mistakenly identified as shifting effects when judging solely based on the voltage difference before and after shifting, and improving the accuracy of end-point voltage regulation action evaluation.

[0017] Before calculating the net voltage regulation effect, the voltage stability state and line current changes corresponding to the first and second stable observation data are assessed for attributability. When there is a significant load change before and after the shift adjustment or the operating state is not comparable, no effective response record or restricted shift record is generated based on the shift adjustment. Only shift adjustments that meet the attributable conditions are evaluated for net voltage regulation effect. Based on the direction of the net voltage regulation effect and its relationship with the effective response threshold, the system decides whether to maintain the target shift or restore the shift to the shift before the shift. This reduces the interference of load start-up and shutdown, short-term disturbances, and acquisition errors on the shift evaluation results, and avoids incorrect shift response judgments due to a single unattributable operating change, thereby improving the stability and reliability of the phase-by-phase bidirectional voltage regulation control process.

[0018] By migrating directional taps with mismatched net voltage regulation direction or insufficient net voltage regulation, a restricted migration record is formed with the corresponding phase, the tap before migration, the target tap, and the source-side voltage range and line current range. The corresponding directional tap migration is only excluded under subsequent identical operating conditions, without permanently restricting the target tap. After the operating conditions continuously leave the original restricted range, it is also possible to re-determine whether to lift the restriction through verification tap migration. Furthermore, existing effective response records can be used to predict candidate load-side voltages and constrain the dispersion between the three-phase candidate voltages. This achieves the effect of dynamically adjusting the tap migration path according to different operating conditions, reducing the repeated execution of inefficient or reverse voltage regulation actions under the same operating conditions, while taking into account the coordination between independent voltage regulation of each phase and the three-phase voltage state. Attached Figure Description

[0019] Figure 1 This is an overall system block diagram of the present invention.

[0020] Figure 2 This is a schematic diagram of the connection structure of the single-phase voltage regulation unit and the acquisition unit of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1 refer to Figure 1-2 A low-voltage distribution area terminal phase-separated bidirectional adaptive voltage regulation system includes phase-separated voltage regulation units, acquisition units, and controllers respectively installed on phase A, phase B, and phase C lines. The three phase-separated voltage regulation units and acquisition units are respectively connected to the controller.

[0023] The phase-specific voltage regulation units corresponding to phases A, B, and C each form an independent voltage regulation channel. The controller can determine the current and target voltage levels for each phase separately. Therefore, when one phase performs boost, deboost, bypass, or reset, it does not require the other two phases to perform the same voltage regulation action.

[0024] Each phase voltage regulation unit includes an autotransformer, a range switching circuit, and a bypass circuit. The autotransformer has voltage regulating taps with different turns ratios, and the range switching circuit is connected to each voltage regulating tap. The controller outputs a range control signal to the range switching circuit, causing the range switching circuit to select the corresponding voltage regulating tap, thereby forming either a boost range or a deboost range.

[0025] The bypass circuit is connected between the input and output sides of the phase-by-phase voltage regulating unit. It is turned on in the bypass position, so that the phase line can be powered without going through the voltage regulating tap.

[0026] Existing field devices employ an autotransformer segmented voltage regulation structure, with existing voltage regulation states including -20%, -10%, bypass, +10%, and +20%, while also possessing three-phase independent regulation and single-phase bypass capabilities. Therefore, this embodiment can directly utilize the aforementioned existing hardware structure to achieve phase-by-phase voltage regulation; however, this application does not limit the five fixed voltage levels or the aforementioned specific voltage regulation percentages to the only implementation form.

[0027] Each voltage level has a corresponding rated voltage adjustment. The rated voltage adjustment for the bypass level is zero, the boost level corresponds to a positive rated voltage adjustment, and the buck level corresponds to a negative rated voltage adjustment. The rated voltage adjustment is determined by the tap ratio and rated input voltage of the autotransformer, or it can be directly obtained from the factory-calibrated voltage level parameters without needing to be fitted from subsequent operating data.

[0028] The term "directed gear shift" as used in this application refers to a gear change from a specific pre-shift gear to a specific target gear. For example, the shift from bypass gear to first boost gear and the shift from first boost gear to bypass gear are two opposite directions of directed gear shift. A brief period of switch-off state or switching transient during gear shifting is not considered a separate gear.

[0029] The acquisition unit collects the source-side voltage at the input side of each phase-by-phase voltage regulating unit, the load-side voltage at the output side, and the line current of the corresponding phase.

[0030] In a three-phase four-wire low-voltage line, the source-side voltage and load-side voltage can be the effective values ​​of the voltages between the corresponding phases and the neutral line. The line current is the effective value of the corresponding phase line current.

[0031] The source-side voltage sampling point and the load-side voltage sampling point are located on both sides of the same phase-by-phase voltage regulation unit, so that the source-side voltage and load-side voltage before and after the first tap position shift always correspond to the same phase and the same voltage regulation unit, avoiding incorrect correspondence of data from different phases or different line positions.

[0032] The controller continuously acquires source-side voltage, load-side voltage, and line current according to a set sampling period, and divides the continuous sampling data into observation periods with equal time lengths. Each observation period includes several continuous sampled values.

[0033] For each observation period, the controller determines the average values ​​of the source-side voltage, load-side voltage, and line current, as well as the difference between the maximum and minimum values ​​of the corresponding sampled quantity within that observation period, and uses the difference between the maximum and minimum values ​​as the fluctuation range of the sampled quantity.

[0034] The source-side voltage stability threshold, load-side voltage stability threshold, and current stability threshold can be obtained during the equipment commissioning and commissioning phase.

[0035] Specifically, sampling is conducted continuously while corresponding phases remain at the same tap level, no tap level switching occurs, and it can be confirmed that no significant large load starts or stops occur. This stage is divided according to the observation period length used during normal operation. The fluctuation amplitudes of source-side voltage, load-side voltage, and line current in each observation period are statistically analyzed, and the corresponding stability thresholds are determined by combining the maximum permissible measurement error of the acquisition unit for the three types of acquired quantities.

[0036] The established stability threshold should at least cover the measurement fluctuations generated by the acquisition unit itself, while also covering the normal short-term fluctuations of the corresponding transformer area under conditions without significant load changes. This avoids misjudging measurement errors or normal small natural variations as a state of line instability.

[0037] When the fluctuation ranges of source-side voltage, load-side voltage, and line current do not exceed their respective stability thresholds within an observation period, the observation period is defined as a stable operating section, and stable observation data is formed by the average value of the three types of collected quantities within the stable operating section.

[0038] Before performing a directed gear shift, the first stable observation data is formed from the most recently formed stable operating segment under the current gear.

[0039] After the gear shift is completed, the controller continues to determine the subsequent observation period according to the same rules, without directly assuming that the gear shift transient has disappeared using a fixed delay time. The first observation period that simultaneously meets the criteria for determining a stable operating section after the gear shift forms the second stable observation data.

[0040] Therefore, the first and second stable observation data are both generated after the actual line enters a stable state, rather than directly using the voltage and current values ​​at the moment of gear switching.

[0041] The controller establishes a gearless reference response relationship for phases A, B, and C respectively, and maintains the corresponding gearless reference response relationship for different gears of the same phase.

[0042] The response relationship without gear shifting reference only uses the stable operating section formed during the period when the corresponding phases are in the same gear and no gear shifting occurs.

[0043] For example, the stable operating section formed when phase A is in the first boost gear is used to establish the no-shift reference response relationship corresponding to the first boost gear of phase A; the data formed when phase A is in the bypass gear or the second boost gear is not directly mixed into this response relationship.

[0044] The first and second stable observation data corresponding to a single actual directed gear shift are not directly used as a gearless differential sample. This is because the gearless reference response relationship describes the natural changes in the line itself when the corresponding gear does not switch, rather than describing the voltage changes caused by gear switching.

[0045] For the same phase and the same tap, the controller obtains stable operating segments arranged in chronological order and groups two stable operating segments that are adjacent in time into a differential segment group. By subtracting the average value of the previous stable operating segment from the average value of the subsequent stable operating segment, the source-side voltage change, the line current change, and the load-side voltage change are obtained.

[0046] This embodiment uses the following relationship to describe the natural response without gear shifting under the same phase and gear position: ; in, This indicates the change in voltage on the load side. This represents the change in source-side voltage. This indicates the change in line current. This represents the source-side voltage variation coefficient. This represents the coefficient of variation of the line current.

[0047] The controller uses at least two differential segment groups to determine and This minimizes the sum of squared errors between the load-side voltage change calculated based on the two variation coefficients and the actual load-side voltage change measured in each differential segment group.

[0048] The method of minimizing the sum of squared errors is used here to provide a definite calculation rule for the two variation coefficients, not to require the introduction of complex prediction models into voltage regulation control.

[0049] When the source-side voltage change and line current change involved in the calculation can provide mutually independent change information, the controller obtains the corresponding two change coefficients. When the two always change synchronously at the same or nearly the same ratio in the existing samples, making it impossible to distinguish the two change coefficients separately, a new unadjusted reference response relationship is not forcibly formed. Instead, subsequent stable operating sections are collected until the samples can support the determination of the two change coefficients.

[0050] Therefore, this application does not require accurate input of power line length, conductor resistance, reactance, and user load model before commissioning. The controller directly obtains the local response relationship based on the actual unadjusted stable operation data generated under the corresponding phase and tap position.

[0051] When the device is first put into operation, each phase and gear may not have accumulated enough stable operating data.

[0052] The controller records the ready state of the response relationship without gear adjustment reference for each phase and each gear.

[0053] When a certain range has not yet formed enough differential samples, or the existing samples are insufficient to determine the source-side voltage variation coefficient and the line current variation coefficient respectively, the range is marked as having an incomplete reference relationship.

[0054] If the reference relationship is not ready, the subsequent evaluation of the net voltage regulation effect based on the load-side reference voltage will not be performed, nor will a valid response record or a limited migration record be generated based on the gear shift migration results.

[0055] To ensure that the device still has basic voltage regulation function when it is first put into operation, if the load side voltage has been continuously exceeding the limit at this time, basic step-by-step voltage increase or step-by-step voltage decrease can be performed according to the relationship between the load side voltage and the target voltage range.

[0056] However, the data before and after gear shifting in the initialization phase described above is not directly used to form valid response records or restricted migration records.

[0057] Once the gear shift is complete, the stable operating range formed during the operation of the new gear can be used to establish the non-adjustment reference response relationship under the new gear.

[0058] Once stable operating data for the corresponding gear position has been generated, which can determine the two change coefficients, it is converted into a baseline relationship ready state. Subsequent directed gear migrations initiated by this gear position can then enter the complete adaptive evaluation process.

[0059] The controller is set to a target voltage range defined by a lower voltage threshold and an upper voltage threshold.

[0060] The lower and upper voltage thresholds are configured when the equipment is put into operation based on the power supply voltage control requirements of the corresponding low-voltage distribution area and the allowable voltage range of downstream equipment. These two thresholds are external operating control parameters and are not calculated from the unadjusted reference response relationship.

[0061] To avoid frequent voltage adjustments caused by instantaneous voltage fluctuations, a voltage over-limit confirmation time is also set.

[0062] The voltage over-limit confirmation time is determined based on the duration of the short-term voltage over-limit that can be recovered by itself during normal operation at the site, and this confirmation time is longer than the duration of the short-term disturbance that needs to be filtered, while not exceeding the allowable voltage regulation response time of the transformer area.

[0063] For example, during commissioning, short-term over-limit events that automatically return to the target voltage range without performing a voltage level shift can be counted. The longest duration among these short-term over-limit events is used as the lower limit for determining the voltage over-limit confirmation time. The controller only initiates voltage level shifting after the voltage has continuously exceeded the confirmation time.

[0064] When the load-side voltage of the corresponding phase is lower than the lower voltage threshold and continues to exceed the voltage limit confirmation time, the voltage boost regulation condition is determined to have occurred.

[0065] When the load-side voltage is higher than the upper voltage threshold and continues to exceed the voltage limit confirmation time, the voltage reduction regulation condition is determined to have occurred.

[0066] When the load-side voltage is within the target voltage range, maintain the current setting.

[0067] When it is necessary to perform voltage increase or decrease, the candidate gears with the same voltage regulation direction are arranged from smallest to largest according to the absolute value of the difference between the rated voltage regulation of the gear and the rated voltage regulation of the current gear.

[0068] The controller first excludes directed gear migrations that already have restricted migration records under the current operating conditions, and then determines the first candidate gear that has not been excluded in the sorting order as the target gear.

[0069] If there is no unremoved directional gear shift in the corresponding pressure regulation direction, the current gear will be maintained, and the restricted gear action will not be forcibly executed.

[0070] After determining the target gear, the controller first obtains the first stable observation data of the gear before migration, then controls the corresponding phase voltage regulation unit to perform directional gear migration, and obtains the second stable observation data of the target gear.

[0071] The controller does not directly evaluate the gear shift based on the difference between the two load-side voltages, but first determines whether the result of the action is attributable.

[0072] The attributable conditions for the outcome of an action include two aspects.

[0073] First, both the first and second stable observation data must be generated in a stable operating section that meets the aforementioned stability conditions, so as to exclude data that was in a state of violent fluctuation before or after the gear shift.

[0074] Secondly, the absolute value of the line current change between two sets of stable observation data must not exceed the current change limit.

[0075] The current variation limit is also determined based on actual operating data. During the equipment commissioning phase, adjacent stable operating sections with the same phase maintaining the same tap level and where no significant load starts or stops can be confirmed are selected, and the variation between their average line current values ​​is statistically analyzed. The upper limit that covers normal current variation from this type of natural operating data is taken, and the current variation limit is determined in conjunction with the measurement error of the current acquisition unit.

[0076] Therefore, the current variation limit represents the acceptable range of natural variation in line current between two stable observations, assuming no significant load switching.

[0077] If the change in line current before and after the adjustment exceeds this range, it cannot be ruled out that downstream pumping equipment, air conditioners, electric heaters, or other large loads may start or stop or experience significant changes in load status during the adjustment period.

[0078] In this case, the directed gear shift is determined to be an action that cannot be attributed to a cause.

[0079] Non-attributable actions do not generate valid response records or restricted migration records. The controller continues to generate stable observation data at the gear position after the gear switch and reassesses whether the load-side voltage triggers the voltage regulation condition.

[0080] This avoids misinterpreting voltage drops caused by sudden increases in user load as an invalid boost level, and also avoids attributing all voltage rises caused by sudden drops in user load to the boost level function.

[0081] For a directed gear shift that satisfies the attributable condition of the action result, the gear before the shift is denoted as g, and the target gear is denoted as h.

[0082] The source-side voltage, load-side voltage, and line current in the first stable observation data are denoted as follows: , and The second stable observation data is denoted as , and .

[0083] When calculating the load-side reference voltage, the reference response relationship without gear adjustment corresponding to the gear position g before migration is used, instead of the response relationship corresponding to the target gear position h.

[0084] This is because the load-side reference voltage needs to represent the level that the load-side voltage should reach in the second stable observation state if, instead of migrating from level g to level h, it remains at level g, given the actual changes in source-side voltage and line current that have already occurred. The load-side reference voltage is defined as follows: ; in, This indicates the load-side reference voltage when the directed gear shift was not executed. and These represent the source-side voltage variation coefficient and the line current variation coefficient of the corresponding phase under the tap position g before migration, respectively.

[0085] After obtaining the load-side reference voltage, the difference between the actual load-side voltage and the load-side reference voltage in the second stable observation data is determined as the net voltage regulation effect of this directed gear shift: ; in, This refers to the net pressure regulation effect generated when shifting from gear g to gear h.

[0086] When the net voltage regulation effect is positive, it means that after excluding the effects of natural changes in the source-side voltage and changes in the line current within the allowable range, this tap shift actually produces a voltage boosting effect.

[0087] When the net pressure regulation effect is negative, it indicates that the actual pressure reduction effect is produced by this gear shift.

[0088] Therefore, this application evaluates not the simple difference between the two load-side voltages before and after the adjustment, but the degree of deviation of the actual adjustment result from the load-side baseline state when the adjustment was not performed.

[0089] For example, if the source-side voltage drops simultaneously during a voltage boost transition, even if the actual load-side voltage only increases slightly, it cannot be directly concluded that the boost level has a weak effect. Conversely, if the source-side voltage happens to rise simultaneously, not all the increase in load-side voltage can be attributed to the voltage regulation effect generated by the boost level itself.

[0090] Through the above processing, the impact of changes in the line itself during the gear adjustment period on the evaluation results can be separated from the role of the gear position.

[0091] The controller also sets an effective response threshold to avoid misjudging small voltage differences caused by baseline fitting errors and acquisition errors as effective voltage regulation.

[0092] The effective response threshold is not an arbitrary fixed percentage.

[0093] In the specific determination, firstly, using the differential samples used to establish the current unadjusted reference response relationship, the deviation between the load-side voltage change calculated based on the current source-side voltage change coefficient and the line current change coefficient and the actual load-side voltage change is statistically analyzed, and the upper limit of the deviation that can cover the normal fitting error of the reference relationship is obtained.

[0094] Then, based on the maximum permissible measurement error of the source-side voltage, load-side voltage, and line current acquisition units, the possible error range that may be formed after these measurement errors are transmitted to the net voltage regulation effect is determined.

[0095] By taking into account both the baseline fitting error and the measurement error, the minimum net voltage regulation effect that can be reliably distinguished from the normal error range is obtained.

[0096] For the pre-shift and target shift gears, the effective response threshold is determined based on the absolute value of the difference between the rated voltage regulation of the two gears. The effective response threshold should not be less than the aforementioned minimum identifiable net voltage regulation effect, and should be less than the difference in rated voltage regulation between the two gears.

[0097] The effective proportional coefficient is the ratio between the effective response threshold and the absolute value of the difference between the rated voltage adjustment amounts of the two gear positions. Therefore, the effective proportional coefficient is greater than 0 and less than 1, and its source can be determined by the actual reference relationship error, the acquisition accuracy, and the gear position design parameters.

[0098] If the current baseline error and acquisition error are so large that they cannot be distinguished from the rated voltage regulation difference between the two gears, it indicates that the current data conditions are insufficient to reliably evaluate the gear migration. This action is not used to generate a valid response record or a limited migration record, but rather to continue accumulating stable operating data at the corresponding gear, or to check the acquisition accuracy.

[0099] For directional shifting of gears in the direction of boost, when the net pressure regulation effect is positive and its absolute value reaches the effective response threshold, the action is considered to have produced an effective boost effect.

[0100] For directional shifting of gears in the direction of pressure reduction, when the net pressure regulation effect is negative and its absolute value reaches the effective response threshold, the action is considered to have produced an effective pressure reduction effect.

[0101] When the above conditions are met, the controller maintains the target gear and generates a valid response record.

[0102] The effective response record includes the corresponding phase, directional gear shift, the net pressure regulation effect corresponding to the action, and the operating conditions when the action occurs.

[0103] When the direction of net pressure regulation is inconsistent with the direction of pressure regulation during this directional gear shift, it indicates that the gear shift action did not produce the required pressure regulation result.

[0104] When the direction of net voltage regulation is correct, but its absolute value does not reach the effective response threshold, it indicates that the gear action is insufficient to reliably distinguish it from the normal error range.

[0105] In both of the above situations, the controller controls the corresponding phase to return to the gear position before migration and forms a restricted migration record.

[0106] The restricted migration record includes the phase, the gear before migration, the target gear, and the associated operating conditions.

[0107] It should be noted that the object of this application is not a target gear position itself, but a directed gear shift from the gear position before the shift to the target gear position under specific phases and specific operating conditions.

[0108] For example, if the transition from the first boost level to the second boost level is recorded as a restricted migration under a heavy load condition, it does not mean that the second boost level will be permanently unusable thereafter. When the line enters a different operating condition, the target boost level can still participate in the boost level selection again according to the corresponding control conditions.

[0109] The operating conditions are determined by the source-side voltage range and the line current range.

[0110] When forming a restricted migration record, the source-side voltage and line current in the first stable observation data are used as the center values ​​of the current operating condition.

[0111] The source-side voltage condition tolerance and line current condition tolerance are formed based on the natural operating data when no switch occurs in the same phase and the same tap.

[0112] Specifically, adjacent stable operating sections can be used to statistically analyze the changes between the average source-side voltage and the average line current to obtain a range that covers normal natural changes. The corresponding operating condition tolerance can then be determined by combining the measurement errors of the source-side voltage and line current acquisition units.

[0113] The source-side voltage range is centered on the source-side voltage at the time when the first stable observation data is formed, and is extended upwards and downwards by one source-side voltage condition tolerance.

[0114] Therefore, the operating conditions are not determined solely by a single precise voltage or current value, but rather by local operating condition ranges formed by the natural variations that are allowed to exist in the actual line under stable operating conditions.

[0115] When subsequent pressure regulation is required, the current operating conditions will be determined based on the most recently formed stable observation data.

[0116] When the phase to be regulated matches the phase in the restricted migration record, the current voltage level matches the voltage level before migration in the record, and the source-side voltage and line current in the current stable observation data fall into the source-side voltage range and line current range corresponding to the restricted migration record, it is determined that the current operating condition matches the restricted migration record.

[0117] Once a match is found, only the directed gear shift from the previous gear to the target gear corresponding to that record is excluded.

[0118] Other directed gear migrations that were not excluded from restricted migration records under the current operating conditions can still participate in target gear selection.

[0119] When there are both historical valid response records and restricted migration records that have been hit under the current operating conditions for the same directed gear shift, the restricted migration record shall prevail, and the gear shift shall be executed directly without relying on the historical valid response.

[0120] Restricted migration records are not permanently maintained.

[0121] The controller continuously determines, based on the newly formed stable observation data, whether the corresponding operating conditions still fall within the source-side voltage range and line current range associated with the original restricted migration record.

[0122] The recovery observation period is determined based on the length of the stable operating section and the continuous characteristics of short-term round-trip changes in field data near the boundary of the operating condition range.

[0123] In practice, the short-term changes in source-side voltage or line current during the commissioning phase, after briefly crossing the boundary of the operating condition range and then returning to the original range, can be statistically analyzed. The recovery observation duration is set to cover the time of such short-term boundary fluctuations, thereby preventing the restriction from being lifted immediately simply because the operating condition has temporarily deviated from its original state during a single observation period.

[0124] When the continuously generated stable observation data no longer meets the original restricted operating conditions and the observation time is restored, the corresponding directed gear will be migrated to the verification-allowed state.

[0125] Allowing verification does not mean you can immediately switch gears.

[0126] Verification gear shifting is only performed when the load-side voltage re-triggers the corresponding directional voltage regulation condition and the target gear selection points to the directional gear shift again.

[0127] The verification gear shift uses the same data processing procedure as the normal gear shift, sequentially generating stable observation data before and after verification, determining whether the action result is attributable, and re-determining the load-side reference voltage and net voltage regulation effect based on the gear shift without adjustment reference response relationship before the shift.

[0128] If the confirmatory gear shift meets the attributable conditions, the net voltage regulation direction is consistent with the voltage regulation direction, and its absolute value reaches the effective response threshold, then the original restricted shift record is released, and a new effective response record is formed using the results of this verification.

[0129] If the net voltage regulation direction is still incorrect or the net voltage regulation is insufficient, the corresponding phase should be restored to the pre-verification position and the restricted migration record should be retained.

[0130] If the verification process itself does not meet the attributable conditions for the action result, then the result cannot prove that the original restricted state has disappeared. In the same way, the gear position before verification is restored, and the original restricted migration record is retained.

[0131] This avoids a single, accidental data change from permanently altering the gear shift status.

[0132] Once a valid response record has been generated for a certain directional gear shift, the load-side voltage after the candidate gear shift is executed can be predicted under similar operating conditions in the future by utilizing its historical net voltage regulation effect.

[0133] The effective response record is associated with both the source-side voltage range and the line current range at the time of its formation.

[0134] Currently, only valid response records containing the most recent stable observation data are used in both the source-side voltage range and the line current range.

[0135] If there are more than two available valid response records for the same directed gear shift under the current operating conditions, the average value of the net pressure regulation effect among these valid response records shall be taken as the current candidate valid response.

[0136] By adding the load-side voltage from the most recently formed stable observation data of the phase to be regulated to the candidate effective response, the candidate load-side voltage of the corresponding phase after the candidate directional gear shift is obtained.

[0137] The effective response for boost migration is positive, so the candidate load-side voltage is higher than the current load-side voltage; the effective response for buck migration is negative, so the candidate load-side voltage, which is lower than the current voltage, can be obtained using the same data processing relationship.

[0138] Since phases A, B, and C can each operate at different speeds, adjusting the speed based solely on the voltage limit of one phase may further increase the difference between the three phase voltages.

[0139] Therefore, for candidate directed gear shifts with available effective response records under the current operating conditions, a three-phase candidate voltage group can be formed before actual execution.

[0140] The phase to be regulated uses the aforementioned candidate load-side voltage; the other two phases use the load-side voltage from their most recently formed stable observation data.

[0141] The controller obtains the maximum and minimum values ​​among the three-phase candidate voltages and uses the difference between the maximum and minimum values ​​as the phase-to-phase voltage discrete quantity.

[0142] The phase-to-phase voltage difference limit and the phase-to-phase voltage discrete quantity use the same physical quantity, that is, they are both expressed as the difference between the maximum and minimum values ​​of the three-phase phase voltage.

[0143] The phase-to-phase voltage difference limit is determined by the phase-to-phase voltage deviation control target or equipment commissioning and acceptance conditions adopted for the corresponding transformer area, and is configured as an operating parameter in the controller. This embodiment does not directly equate the negative sequence voltage imbalance with the phase-to-phase voltage dispersion, nor does it require the conversion of the negative sequence voltage imbalance into this limit.

[0144] When the phase-to-phase voltage dispersion formed by the candidate gear does not exceed the phase-to-phase voltage difference limit, the current candidate directed gear migration is allowed.

[0145] When the phase-to-phase voltage difference limit is exceeded, the current candidate directional gear shift is excluded.

[0146] The controller continues to check other directed gear migrations that were not excluded by restricted migration records under the current operating conditions and have available valid response records, in the same voltage regulation direction, according to the order of the absolute value of the voltage regulation change of the candidate gear relative to the current gear from small to large.

[0147] If there are other candidate gears that satisfy the phase-to-phase voltage discrete constraint, then perform the directed gear migration for that candidate gear; otherwise, keep the current gear.

[0148] When the equipment is running for the first time or when a directional gear shift has not previously generated a valid response record under the current operating conditions, the controller will not artificially assign a theoretically valid response value.

[0149] The directed gear shift can still be performed for the first time according to the pressure regulation conditions, restricted shift records, and target gear selection rules.

[0150] After execution, the process involves attribution judgment of the aforementioned action results, determination of the load-side reference voltage, and evaluation of the net voltage regulation effect.

[0151] When this action meets the valid response conditions, an initial valid response record for the corresponding directed gear shift is generated.

[0152] Therefore, the three-phase candidate voltage prediction in this application is a further control measure after the actual effective response data has been formed, rather than a prerequisite for the start of operation of the entire voltage regulation system.

[0153] Example 2 This application can be applied to low-voltage distribution areas with long power supply distances, concentrated end loads, and significant low-voltage fluctuations.

[0154] According to existing on-site data, the distribution transformer capacity of the #2 substation in a certain community is 100kVA, the transformer outlet voltage is 235V, there are 9 low-voltage users, the total length of the power supply line is approximately 1000m, and the upstream section uses 50mm² power. 2 Overhead aluminum conductor, with 25mm² used in the latter section. 2 The lowest voltage recorded at the end of the line on September 14, 2025, was 171V, and the lowest voltage at the proposed equipment installation location was 183V. The load downstream of this line includes water pumping equipment, lighting, air conditioning, electric heaters, and other household appliances, and there is a concentration of loads during peak periods.

[0155] This working condition demonstrates the practical necessity of attributing the results of the actions in this application.

[0156] For long-distance low-voltage lines with smaller conductor diameters in the latter part, an increase in user load will cause both line current and line voltage drop to increase simultaneously; when the load in the entire distribution area changes, the source-side voltage itself may also change. Therefore, the change in load-side voltage before and after a tap change does not necessarily all come from the voltage regulation unit.

[0157] Especially for loads with obvious start-stop characteristics, such as water pumps, air conditioners, and electric heaters, if the operating state changes during the gear switching period, directly evaluating the gear effect by the voltage difference on the load side before and after the gear adjustment is easy to cause misjudgment.

[0158] The existing field devices are already able to perform basic voltage ramping control based on the load-side voltage, that is, to ramp up the voltage when the voltage is below the lower limit, to ramp down the voltage when the voltage is above the upper limit, and to bypass or maintain the corresponding operating state when the voltage is within the allowable range.

[0159] Therefore, this application does not take ordinary voltage over-limit shifting as the main improvement, but adds directional shifting restrictions based on the existing phase-separated bidirectional voltage regulation hardware, such as shifting reference response relationship, action result attribution judgment, net voltage regulation effect evaluation, and operating condition correlation.

[0160] Existing operational data also records that after the on-site device was put into operation on November 2, 2025, the boost function was activated, and the voltage of phase A was maintained above 215.7V; when 24-hour continuous monitoring was carried out on November 3, 2025, the device was in the second boost mode, and the voltage of phase A was stable at 216.7V.

[0161] Existing operational data does not synchronously record complete source-side voltage, load-side voltage, and line current data before and after each directed shift during the newly added control process of this application, nor does it have readily available reference response coefficients without shifting or calculation results for net voltage regulation. Therefore, this implementation does not utilize 215.7V or 216.7V to reverse-engineer the experimental results of the algorithm of this application.

[0162] After the controller of this application is actually adopted, the acquisition unit should obtain the first stable observation data and the second stable observation data for each directed gear shift, and form the corresponding load-side reference voltage and net voltage regulation function in the manner described above.

[0163] Therefore, the existing data on site is used to support the feasibility of the application scenario and the phase-by-phase bidirectional voltage regulation hardware of this application, while the newly added adaptive control part is fully disclosed through a clear data acquisition process, calculation relationship, parameter source and anomaly handling branch.

[0164] This application establishes the following continuous control relationship during operation: Each phase first establishes a no-gear reference response relationship using stable operating data under the same gear and no-gear switching states; after the load-side voltage continuously exceeds the limit, the voltage regulation direction and candidate gear are determined; stable observation data are formed before and after the directed gear migration is performed; it is first determined whether the result of this action can be attributed to this gear migration; after the attribution condition is met, the no-gear reference response relationship of the gear before migration is used to form the load-side reference voltage under the no-gear state; the difference between the actual load-side voltage and the reference voltage forms the net voltage regulation effect; based on the direction and magnitude of the net voltage regulation effect, it is determined whether to maintain the target gear or restore the gear before migration, and a valid response record or a restricted migration record is formed accordingly; subsequently, under the same operating conditions, the restricted migration record is used to adjust the gear selection path, and after the operating conditions continue to change, a verification gear migration is used to determine whether to lift the restriction.

[0165] In the above processing, the data sources without a reference response relationship, the formation conditions of the first and second stable observation data, the attributable conditions of the action results, the effective response threshold, the operating condition range, and the limited migration recovery conditions all have clear acquisition bases. When there is insufficient data, the reference relationship is unidentifiable, the gear action is unattributable, or the existing accuracy is insufficient to reliably distinguish the net voltage regulation effect, no evaluation result is forcibly generated. Instead, the process is handled by continuing sampling, maintaining the existing gear, or re-entering the subsequent judgment, so that the entire control process can be continuously implemented according to the determined data relationship.

[0166] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A phase-separated bidirectional adaptive voltage regulation system for the end of a low-voltage distribution area, comprising a phase-separated voltage regulation unit, a data acquisition unit, and a controller connected to the phase-separated voltage regulation unit and the data acquisition unit respectively installed on phase A, phase B, and phase C lines, characterized in that: The phase-separated voltage regulating unit has a boost setting, a bypass setting, and a deboost setting, and each phase-separated voltage regulating unit can switch settings independently. The acquisition unit acquires the source-side voltage at the input side of each phase-by-phase voltage regulation unit, the load-side voltage at the output side, and the line current of the corresponding phase. The controller establishes a no-adjustment reference response relationship for each phase. The no-adjustment reference response relationship is formed by the stable operating section during which the phase-by-phase voltage regulation unit of the corresponding phase maintains the same level and no level switching occurs. It is used to characterize the correspondence between source-side voltage change, line current change and load-side voltage change. When the load-side voltage of any phase triggers the voltage regulation condition, the controller determines the directed shift of that phase from the current shift to the target shift. Before the directed shift is executed, the first stable observation data is generated, and after the shift is switched, the second stable observation data is generated. Both the first and second stable observation data include the source-side voltage, the load-side voltage, and the line current. Based on the line current change between the first and second stable observation data and the voltage stability state corresponding to the two sets of stable observation data, the controller determines whether the directed gear shift meets the attributable conditions of the action result. When the conditions for attributable action results are met, the controller determines the load-side reference voltage under the condition that the directed shift was not performed, based on the no-shift reference response relationship, source-side voltage change and line current change; and determines the net voltage regulation effect of the directed shift based on the deviation between the actual load-side voltage and the load-side reference voltage in the second stability observation data. When the direction of the net pressure regulation is consistent with the direction of the current directional gear shift, and the absolute value of the net pressure regulation reaches the effective response threshold, the target gear is maintained and an effective response record is formed. When the direction of the net voltage regulation is inconsistent with the direction of the voltage regulation during this directional shift, or when the absolute value of the net voltage regulation does not reach the effective response threshold, the corresponding phase is controlled to return to the shift position before the shift, and the current directional shift is associated with the operating conditions when the directional shift is performed to form a restricted shift record; the operating conditions are determined by the source-side voltage range and line current range of the corresponding phase. When the controller subsequently meets the operating conditions associated with the restricted migration record, it determines the target gear for the corresponding phase after excluding the directed gear migration corresponding to the restricted migration record.

2. The low-voltage distribution area terminal phase-separated bidirectional adaptive voltage regulation system according to claim 1, characterized in that: Each phase voltage regulation unit includes an autotransformer, a tap changer circuit, and a bypass circuit; The autotransformer has taps with different turns ratios; the gear switching circuit is connected to the taps respectively, and selects the corresponding tap according to the gear control signal output by the controller to form a boost gear or a buck gear. The bypass circuit is connected between the input and output sides of the phase-splitting voltage regulating unit and is turned on in the bypass position; The acquisition unit includes source-side voltage sampling points, load-side voltage sampling points, and line current sampling points; the source-side voltage sampling points and load-side voltage sampling points are respectively set on the input side and output side of the phase-by-phase voltage regulation unit, and the line current sampling points are set on the corresponding phase lines.

3. The low-voltage distribution area terminal phase-separated bidirectional adaptive voltage regulation system according to claim 2, characterized in that: The controller divides the continuously collected source-side voltage, load-side voltage, and line current into observation periods with the same time length, and determines the average value and fluctuation range of the source-side voltage, load-side voltage, and line current in each observation period. The fluctuation range is the difference between the maximum and minimum values ​​of the corresponding data collected within the same observation period; When the fluctuation range of the source-side voltage does not exceed the source-side voltage stability threshold, the fluctuation range of the load-side voltage does not exceed the load-side voltage stability threshold, and the fluctuation range of the line current does not exceed the current stability threshold, the corresponding observation period is determined as the stable operation section. Stable observation data are formed using the average source-side voltage, average load-side voltage, and average line current within the stable operating section. Before performing a directed gear shift, the first stable observation data is formed from the stable operating section under the current gear; after the gear shift is completed, the second stable observation data is formed from the first observation period that meets the criteria for a stable operating section.

4. The low-voltage distribution area terminal phase-separated bidirectional adaptive voltage regulation system according to claim 3, characterized in that: The controller acquires at least three stable operating segments arranged in chronological order during the period when the corresponding phases remain at the same gear and no gear switching occurs, and groups two stable operating segments that are adjacent in time into a differential segment group. For each differential segment group, the average value of the previous stable operating segment is subtracted from the average value of the next stable operating segment to obtain the source-side voltage change, line current change, and load-side voltage change, respectively. Using the source-side voltage change and line current change as input quantities, and the load-side voltage change as response quantity, determine the source-side voltage change coefficient and the line current change coefficient. The source-side voltage variation coefficient and the line current variation coefficient minimize the sum of squared errors between the calculated load-side voltage variation and the measured load-side voltage variation. The source-side voltage variation coefficient and the line current variation coefficient constitute the reference response relationship without adjustment for the corresponding phase and the corresponding tap.

5. The low-voltage distribution area terminal phase-separated bidirectional adaptive voltage regulation system according to claim 4, characterized in that: The voltage regulation conditions are determined by the lower and upper voltage thresholds of the target voltage range; When the load-side voltage of the corresponding phase is lower than the lower voltage threshold and continues to exceed the voltage limit confirmation time, the controller determines the target level along the voltage boost direction; When the load-side voltage of the corresponding phase is higher than the upper voltage threshold and continues to exceed the voltage limit confirmation time, the controller determines the target level along the step-down direction; When the load-side voltage of the corresponding phase is within the target voltage range, maintain the current setting; When determining the target gear along the direction of pressure increase or decrease, the gears located in the corresponding pressure adjustment direction are arranged in ascending order of pressure adjustment increment relative to the current gear, and the first gear that has not been eliminated in the corresponding directional gear migration is determined as the target gear. When there is no unremoved directional gear shift in the corresponding pressure regulation direction, maintain the current gear.

6. The low-voltage distribution area terminal phase-separated bidirectional adaptive voltage regulation system according to claim 5, characterized in that: The conditions for attributing the action result include: the observation periods for which the first stable observation data and the second stable observation data are generated both meet the criteria for determining the stable operating section, and the absolute value of the difference between the line current in the first stable observation data and the second stable observation data does not exceed the current change limit. If any of the above conditions are not met, this directed gear shift will be determined as an action that cannot be attributed to a cause. For actions not attributable to the controller, the controller maintains the gear position after the gear shift until subsequent stable observation data is generated. It does not generate a valid response record or a restricted migration record based on this directed gear shift, and re-determines whether to trigger the voltage regulation condition based on subsequent stable observation data.

7. A low-voltage distribution area terminal phase-separated bidirectional adaptive voltage regulation system according to claim 6, characterized in that: For directed gear shifts that meet the attributable conditions for the action result, the controller subtracts the source-side voltage from the source-side voltage in the first stable observation data from the source-side voltage in the second stable observation data to obtain the change in source-side voltage; and subtracts the line current from the line current in the first stable observation data from the line current in the second stable observation data to obtain the change in line current. The load-side reference voltage is obtained by adding the product of the source-side voltage change and the source-side voltage change coefficient, the product of the line current change and the line current change coefficient, and the load-side voltage in the first stable observation data, without the execution of this directional tap migration. The difference between the actual load-side voltage and the load-side reference voltage in the second stable observation data is determined as the net voltage regulation effect; When the net pressure regulation effect is positive, it means that the current directed gear shift produces a pressure increase effect compared to the state before the directed gear shift was performed; when the net pressure regulation effect is negative, it means that the current directed gear shift produces a pressure decrease effect compared to the state before the directed gear shift was performed. Each gear has a rated voltage adjustment amount, which is the change in output voltage generated by the corresponding gear relative to the bypass gear under the rated input voltage. The effective response threshold is the product of the absolute value of the difference between the rated voltage adjustment of the gear before migration and the target gear, and the effective proportional coefficient, where the effective proportional coefficient is greater than 0 and less than 1.

8. A low-voltage distribution area terminal phase-separated bidirectional adaptive voltage regulation system according to claim 7, characterized in that: The restricted migration record includes the phase, the tap position before migration, the target tap position, and the source-side voltage range and line current range of the associated operating conditions; The source-side voltage range is centered on the source-side voltage at the time when the first stable observation data is formed, and the source-side voltage operating condition tolerance is half-width. The line current range is centered on the line current when the first stable observation data is formed, and the line current operating condition tolerance is half the width. Both the source-side voltage tolerance and the line current tolerance are positive. During subsequent pressure regulation, the current operating conditions will be determined based on the most recently formed stable observation data; When the phase to be regulated is consistent with the phase, the current tap is consistent with the tap before migration, and the source-side voltage and line current in the recently formed stable observation data fall into the source-side voltage range and the line current range respectively, it is determined that the current operating condition meets the operating condition associated with the restricted migration record. The controller excludes directed gear migrations from the previous gear to the target gear, and retains directed gear migrations from the previous gear to other gears that are not excluded from restricted migration records under the current operating conditions.

9. A low-voltage distribution area terminal phase-separated bidirectional adaptive voltage regulation system according to claim 8, characterized in that: When the continuously generated stable observation data does not meet the operating conditions associated with the restricted migration record, and the duration reaches the recovery observation time, the controller will convert the directed gear migration corresponding to the restricted migration record into a verification-allowed state. When the subsequent pressure regulation conditions point to a directed gear shift again, a verification gear shift is performed, and it is determined whether the verification gear shift meets the attributable conditions of the action result. When the confirmatory gear shift does not meet the attributable conditions for the action result, the corresponding phase is restored to the gear before the confirmatory gear shift, and the restricted shift record is retained. When the confirmatory gear shift meets the attributable conditions for the action result, the net pressure regulation effect of the confirmatory gear shift is determined based on the response relationship without gear shifting baseline. When the direction of the net voltage regulation is consistent with the direction of the voltage regulation of the confirmatory gear shift, and the absolute value of the net voltage regulation reaches the effective response threshold, the corresponding restricted migration record is released and an effective response record is formed. When the direction of the net voltage regulation is inconsistent with the direction of the voltage regulation during the confirmatory gear shift, or when the absolute value of the net voltage regulation does not reach the effective response threshold, the corresponding phase is restored to the gear before the confirmatory gear shift, and the restricted shift record is retained.

10. A low-voltage distribution area terminal phase-separated bidirectional adaptive voltage regulation system according to claim 9, characterized in that: The effective response record includes the corresponding directional tap shift, net voltage regulation effect, and the source-side voltage range and line current range when the effective response record is formed. The source-side voltage range is centered on the source-side voltage at the time when the first stable observation data is formed, and the source-side voltage condition tolerance is half-width; the line current range is centered on the line current at the time when the first stable observation data is formed, and the line current condition tolerance is half-width. For candidate directional tap shift, the controller obtains the corresponding net voltage regulation effect from the effective response records of the source-side voltage and line current in the source-side voltage range and line current range, respectively, which contain the most recently formed stable observation data. When there are more than two effective response records, the average value of the net voltage regulation effect in each effective response record is used as the candidate effective response. The controller adds the current load-side voltage of the corresponding phase to the candidate valid response to determine the candidate load-side voltage after migrating to the candidate target level; The candidate load-side voltage and the current load-side voltage of the other two phases are combined to form a three-phase candidate voltage group, and the difference between the maximum and minimum phase voltage in the three-phase candidate voltage group is determined as the phase-to-phase voltage discrete quantity. When the phase-to-phase voltage dispersion does not exceed the phase-to-phase voltage difference limit, perform candidate directed gear shifting. When the phase-to-phase voltage dispersion exceeds the phase-to-phase voltage difference limit, the current candidate directional gear shift is excluded, and the candidate target gear is re-determined from the remaining candidate directional gear shifts in the same voltage regulation direction in ascending order of voltage regulation increment relative to the current gear. If there are no other candidate gear shifts that meet the current operating conditions and have valid response records, maintain the current gear.

Images