On-load voltage regulation method, device and storage medium based on existing transformer

Abstract

The present application relates to the technical field of transformers, and discloses a method, device and storage medium for on-load voltage regulation based on an existing transformer. The method provides a transient overvoltage suppression device on the switch, one end of which is connected to the action end, and the other end is connected to the contact end corresponding to the intermediate gear voltage, and its conduction voltage is greater than the maximum voltage difference between the action end and the contact end. The action end is connected to a phase correction capacitor, and then connected to the primary side bushing through this capacitor. Each contact end is connected to a corresponding current limiting inductor, and through them is connected to a tap with a different number of turns of the primary side winding of the transformer, and the other tap of the winding is connected to another primary side bushing. Then the voltage value of the secondary side of the transformer is detected, and according to this value, the action end is driven to connect to the contact end that is positively correlated with the secondary voltage value. This method can enable existing transformers to achieve on-load voltage regulation, effectively improving the stability of the power supply voltage.

Description

Technical Field

[0001] The present application relates to the technical field of transformers, and in particular to an on-load voltage regulation method, device, and storage medium based on an existing transformer. Background Art

[0002] With the development of renewable energy, distribution transformers are required to handle a large amount of renewable energy backhaul, resulting in significant voltage fluctuations on the low-voltage side. No-load voltage regulation and on-load voltage regulation are the two main methods of transformer voltage regulation. No-load voltage regulation involves changing the turns ratio of the high-voltage winding by changing the taps of the transformer when both the primary and secondary sides are disconnected from the power supply, thereby adjusting the output voltage. For example, a 10kV / 0.4kV three-speed transformer can adjust the primary winding turns by adjusting the tap changer to different taps, thereby changing the secondary output voltage while maintaining the primary power supply voltage. On-load voltage regulation uses the on-load tap changer to switch from one tap to another without interrupting the load current. This changes the transformer's transformation ratio by changing the effective turns of the winding, thereby adjusting the output voltage. During this switching process, transition resistors are used to limit the current between the two levels to ensure that the transformer does not lose power.

[0003] Currently, most existing transformers are designed for off-load voltage regulation, making it difficult to adjust voltage during large voltage fluctuations. This results in unsatisfactory power quality issues, such as high and low voltage fluctuations for users. However, on-load voltage regulation requires the purchase of new transformers, which is very expensive. Therefore, it is crucial to improve existing off-load voltage regulation transformers to enable on-load voltage regulation. Summary of the Invention

[0004] In order to enable an existing off-load tap-regulating transformer to perform on-load tap-regulation, the present application provides an on-load tap-regulation method, device, and storage medium based on an existing transformer.

[0005] In a first aspect, the present application provides an on-load voltage regulation method based on an existing transformer, which adopts the following technical solution:

[0006] A method for on-load voltage regulation based on an existing transformer, based on an off-load voltage regulating tap-changer connected to the transformer, comprises the following steps: arranging a transient overvoltage suppression device on the off-load voltage regulating tap-changer, wherein one end of the transient overvoltage suppression device is connected to an action end of the off-load voltage regulating tap-changer, and the other end is connected to a contact end corresponding to an intermediate gear voltage in the off-load voltage regulating tap-changer, wherein the conduction voltage of the transient overvoltage suppression device is greater than the positive and negative maximum voltage gear voltage difference between the action end and the contact end corresponding to the intermediate gear voltage; the action end is connected to a phase correction capacitor and is connected to a primary-side bushing via the phase correction capacitor; each contact end is connected to a current-limiting reactor in a one-to-one correspondence, and different contact ends are connected to taps with different numbers of turns on the primary-side winding of the transformer via corresponding current-limiting reactors; a tap of the primary-side coil of the transformer away from the contact end is connected to another primary-side bushing; detecting a secondary voltage value on the secondary side of the transformer; and driving the action end to connect to a contact end corresponding to a positive correlation with the secondary voltage value according to the secondary voltage value.

[0007] Optionally, if the secondary voltage value is low, the driving action end is connected to the contact end that reduces the number of turns of the primary side winding; if the secondary voltage value is high, it is connected to the contact end that increases the number of turns of the primary side winding.

[0008] By adopting the above technical solution, the contact terminal connected to the action end of the no-load voltage-regulating tap changer is adjusted by detecting the voltage value on the secondary side of the transformer, thereby adjusting the number of turns of the primary side winding in real time, stabilizing the output voltage on the secondary side, solving the problem of unstable power supply caused by voltage fluctuations, and ensuring the normal operation of users' electrical equipment; a transient overvoltage suppression device is set on the no-load voltage-regulating tap changer to prevent transient overvoltage from damaging the equipment when the tap changer is operated, protecting the transformer, tap changer and other related electrical equipment, and improving the reliability of the system operation; the phase correction capacitor connected to the action end can improve the phase relationship of the circuit, increase the power factor, reduce reactive power loss, and improve the efficiency of power transmission; the current-limiting inductor connected to each contact end can limit the circulating current between the windings, ensuring the safety and stability of the on-load voltage regulation process; the precise driving of the action end to connect different contact ends realizes the fine adjustment of the transformer output voltage, improves the power supply quality, and reduces the risk of damage to electrical equipment due to excessive voltage deviation.

[0009] Optionally, the method further comprises the following steps:

[0010] The transient overvoltage suppression device includes a plurality of parallel-connected silicon bidirectional diodes, each of which is connected in series with a conducting device;

[0011] calculating a secondary fluctuation voltage value of the secondary voltage value within a recent time period;

[0012] Determining the voltage fluctuation range to which the secondary fluctuation voltage value belongs;

[0013] Matching a corresponding conductive device according to the voltage fluctuation range;

[0014] The matched conductive devices are turned on.

[0015] By adopting the above technical solution, the transient overvoltage suppression device is composed of a plurality of silicon bidirectional diodes connected in parallel and each of which has a conducting device connected in series. The conducting devices are matched according to the secondary fluctuation voltage value calculated according to the secondary voltage value. When the voltage fluctuation is small, the branch with a lower conduction voltage can be enabled to accurately suppress the transient overvoltage. When the voltage fluctuation is large, the branch with a higher conduction voltage can be enabled to adapt to different degrees of voltage fluctuation, ensure reliable on-load voltage regulation, and improve the adaptability and stability of the voltage regulation system. At the same time, precise matching of the conducting devices can reduce the impact of voltage fluctuations on the power quality, ensure the normal operation of electrical equipment, improve the user's power experience, and can also reduce the electrical shock of the equipment, reduce the failure rate, extend the service life of the equipment, and improve the economy of the power system. In addition, this automatic matching control according to the secondary fluctuation voltage value reflects the intelligence of the voltage regulation system and meets the automation and intelligent development needs of modern power systems.

[0016] Optionally, the method further comprises the following steps:

[0017] The transient overvoltage suppression device includes a plurality of parallel-connected silicon bidirectional diodes, each of which is connected in series with a conducting device;

[0018] calculating a secondary fluctuation frequency value of the secondary voltage value within a recent time period;

[0019] Determine the frequency interval to which the secondary fluctuation frequency value belongs, and match a corresponding conductive device according to the frequency interval to conduct the conductive device;

[0020] If, in a recent time period, the secondary fluctuation frequency value repeatedly jumps between adjacent frequency intervals, and the number of jumps is greater than a preset threshold, the action period of the action end is adjusted in a positive correlation with the number of jumps;

[0021] The greater the number of lateral jumps, the longer the action cycle; the smaller the number of lateral jumps, the shorter the action cycle.

[0022] By adopting the above technical solution, the transient overvoltage suppression device utilizes multiple silicon bidirectional diodes connected in parallel and each with a conductive device connected in series, matches the conductive devices according to the frequency interval to which the secondary fluctuation frequency value belongs, accurately suppresses transient overvoltages of different frequencies, and ensures the safe and stable operation of the equipment; when the secondary fluctuation frequency value repeatedly jumps in adjacent frequency intervals and the number of times exceeds the preset threshold, the action end action cycle is adjusted in positive correlation with the number of jumps, the action strategy is optimized, the equipment life is extended and the voltage regulation efficiency is improved; the precise suppression of transient overvoltages and the reasonable adjustment of the action cycle reduce system interference and instability factors, and improve the operating stability and power supply reliability of the on-load voltage regulation system; the system is automatically controlled according to the secondary fluctuation frequency value and the number of jumps, which enhances the adaptability and intelligence level, conforms to the intelligent development trend of modern power systems, and improves the overall performance.

[0023] Optionally, the action end is linked to a drive motor, and the method includes the following steps:

[0024] adjusting the speed of the driving motor according to the anti-correlation of the secondary voltage value;

[0025] The greater the voltage value of the secondary side is, the lower the movement speed of the driving motor is; and the smaller the voltage value of the secondary side is, the greater the movement speed of the driving motor is.

[0026] By adopting the above technical solution, when the secondary side voltage value is low, the driving motor moves quickly, and the contact end that reduces the number of turns of the primary side winding is connected to increase the secondary voltage. When the voltage value is high, the motor moves slowly, and the contact end that increases the number of turns of the primary side winding is connected to avoid over-regulation. This method of adjusting the driving motor movement speed in real time according to the voltage value in an anti-correlated manner improves the voltage regulation efficiency and accuracy, ensures the stability of the output voltage, and guarantees the normal operation of electrical equipment; at the same time, it can also avoid unnecessary high-speed operation of the motor, reduce equipment wear, mechanical loss and energy consumption, extend the service life of the equipment, reduce maintenance costs, and improve the economy of the on-load voltage regulation system; and adaptively adjust the motor speed when the voltage fluctuates to make the voltage regulation process smooth, prevent instability problems such as system oscillation, improve the reliability and stability of the on-load voltage regulation system, and reduce interference with other parts of the power system.

[0027] Optionally, a lightning arrester is connected in parallel to the phase correction capacitor.

[0028] By adopting the above technical solution, during power system operation, lightning strikes, operations, and other factors can cause overvoltage. The lightning arrester can quickly conduct when overvoltage occurs, directing charge into the ground to limit the voltage amplitude. Phase correction capacitors are crucial for improving circuit phase relationships and increasing power factor. When connected in parallel with the lightning arrester, the lightning arrester takes priority in overvoltage, protecting the phase correction capacitor from damage, ensuring its continued stable operation, maintaining normal system operation, reducing system failures caused by phase problems, and improving power system reliability. At the same time, the lightning arrester reduces the probability of damage to the phase correction capacitor, reduces the frequency of equipment repair and replacement, saves costs, and effectively controls the maintenance cost of the on-load tap-changing system. In addition, connecting the lightning arrester and phase correction capacitor in parallel also reduces the risk of electrical accidents caused by overvoltage, ensuring the safety of equipment and personnel.

[0029] Optionally, the inductance value of each current-limiting reactor is equal, and its inductive reactance is equal to the capacitive reactance of the phase correction capacitor. The circulating current of the inductive reactance of each current-limiting reactor at the gear voltage of the adjacent gear of the existing transformer is less than 1% of the rated current; the action end can choose to stay in the position between the two gears and simultaneously power the circuits of the two gears.

[0030] By adopting this technical solution, the no-load tap changer position is adjusted by driving a stepper motor, while a current-limiting reactor suppresses circulating current and a phase-correction capacitor offsets its reactance to the load current, thus avoiding complex technologies to achieve live voltage regulation. Furthermore, a silicon bidirectional diode suppresses transient overvoltages, and the impedance matching characteristics of the inductive-capacitive three-port circuit enable simultaneous power supply to two taps, creating a tap position multiplier and achieving a smooth voltage regulation ratio of 1.25%.

[0031] Optionally, the method further comprises the following steps:

[0032] When the action end performs an action, obtaining magnetic field change data on the primary side;

[0033] Performing spectrum analysis on the magnetic field change data to obtain magnetic field change data in frequency domain signals;

[0034] Calculate the amplitude and phase of the magnetic field change data under the frequency domain signal;

[0035] Extracting spectrum features based on amplitude and phase, wherein the spectrum features include peak frequency band and frequency band energy distribution;

[0036] Normalizing the frequency spectrum features to obtain corresponding eigenvalues;

[0037] The corresponding silicon bidirectional diode is matched and turned on according to the characteristic value.

[0038] By adopting the above technical solution, when the action is executed at the action end, the primary side magnetic field change data is obtained in real time and spectrum analysis is performed, and the time domain signal is converted into a frequency domain signal, which can clearly present the change characteristics of different frequency components. The amplitude and phase are calculated, the spectrum characteristics are extracted and normalized to obtain the characteristic value, which is then matched with the conductive silicon bidirectional diode, which can accurately suppress transient overvoltages and improve the pertinence and effectiveness of the suppression. This method can quickly respond to transient overvoltages, discharge overvoltage energy in time, protect the insulation and normal operation of the equipment, has adaptive protection capabilities, and can comprehensively and reliably protect the equipment. Accurately suppressing transient overvoltages can reduce interference with the power system, ensure stable operation of the system, improve power quality, enhance power system reliability, reduce the risk of power outages, and meet users' needs for continuous and stable power supply.

[0039] Optionally, after calculating the amplitude and phase of the magnetic field change data under the frequency domain signal, the method further includes the following steps:

[0040] Extracting a signal within a first characteristic frequency band from the magnetic field change data under the frequency domain signal;

[0041] Calculating the dispersion degree of the amplitudes of all frequency points within the first characteristic frequency band as a first dispersion coefficient;

[0042] If the first discrete coefficient is greater than a preset first threshold, adjusting the execution speed of the action end in an anti-correlation manner according to the first discrete coefficient;

[0043] Extracting a signal within a second characteristic frequency band from the magnetic field change data under the frequency domain signal;

[0044] Calculating the dispersion degree of the amplitudes of all frequency points within the second characteristic frequency band as a second dispersion coefficient;

[0045] If the second discrete coefficient is greater than a preset second threshold, adjusting the execution speed of the action end according to the positive correlation of the second discrete coefficient;

[0046] The values ​​within the first characteristic frequency band are all greater than the values ​​within the second characteristic frequency band.

[0047] By adopting the above technical solution, the solution achieves adaptive adjustment of the execution speed of the action end by monitoring and analyzing the characteristics of magnetic field changes in different frequency bands. When the amplitude dispersion of the first characteristic frequency band (high frequency band) exceeds the first threshold, it indicates that the magnetic field changes are drastically and unstable, possibly due to high-frequency interference. In this case, anti-correlation reduces the execution speed to avoid malfunction and equipment damage. When the amplitude dispersion of the second characteristic frequency band (low frequency band) exceeds the second threshold, it means that the magnetic field fluctuates greatly, possibly related to low-frequency oscillations. In this case, positive correlation increases the execution speed to prevent the low-frequency oscillations from exacerbating. This adaptive adjustment makes the action end action more consistent with the actual system, improves the efficiency and accuracy of voltage regulation, reduces adjustment errors, reduces system losses, enhances anti-interference capabilities, and ensures stable system operation.

[0048] In a second aspect, the present application provides an on-load voltage regulating device based on an existing transformer, which adopts the following technical solution:

[0049] An on-load voltage regulation device based on an existing transformer includes a processor, wherein the processor executes the steps of any one of the above-mentioned on-load voltage regulation methods based on an existing transformer.

[0050] In a third aspect, the present application provides a storage medium that adopts the following technical solution:

[0051] A storage medium stores a program, wherein the program, when executed by a processor, implements the steps of any one of the above-mentioned on-load voltage regulation methods based on an existing transformer.

[0052] In summary, this application includes at least one of the following beneficial technical effects:

[0053] A voltage regulation execution controller is added to drive the stepper motor, detect the voltage at the output end of the transformer, and realize closed-loop adjustment of the voltage level of the existing no-load tap changer, solving the problem of frequent voltage regulation under power.

[0054] The high reactance rate of the current-limiting reactor is used to limit the current and suppress the circulating current during the gear shifting process; at the same time, a phase correction capacitor is connected in series to offset the reactance of the current-limiting reactor to the load current, so that it can suppress the circulating current at a high ratio and the reactance to the load current is zero, avoiding the complex transition resistor and multiple groups of contacts technology, and only relying on a simple no-load voltage tap changer to achieve live voltage regulation.

[0055] Through silicon bidirectional diode protection, transient overvoltage during the gear shifting process is effectively suppressed to ensure safe operation of the equipment.

[0056] With the help of the impedance matching characteristics of the inductive and capacitive three-port circuit, the operating end can stay between two gears, realizing simultaneous power supply of two taps, constructing a tap gear multiplication effect, and achieving smooth voltage regulation of each gear at a ratio of 1.25%. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is an on-load tap-changing circuit diagram based on an existing transformer.

[0058] Figure 2 The transient overvoltage suppression device includes a circuit diagram of a plurality of parallel-connected silicon bidirectional diodes.

[0059] Figure numerals: 1. existing transformer; 2. no-load tap-changer; 3. transient overvoltage suppression device; 4. phase correction capacitor; 5. current-limiting reactor; 6. contact terminal; 7. primary side bushing; 8. conducting device; 9. drive motor; 10. voltage regulation execution controller; 11. lightning arrester. DETAILED DESCRIPTION

[0060] Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings.

[0061] Throughout this specification, reference to the terms "certain embodiments," "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0062] The embodiment of the present application discloses a method for on-load voltage regulation based on an existing transformer, referring to Figure 1 , based on the no-load tap changer 2 connected to the transformer, including the following steps:

[0063] A transient overvoltage suppression device 3 is provided on the off-load tap-changer 2. One end of the transient overvoltage suppression device 3 is connected to the operating terminal of the off-load tap-changer 2, and the other end is connected to the contact terminal 6 corresponding to the intermediate voltage range of the off-load tap-changer 2. The conduction voltage of the transient overvoltage suppression device 3 is greater than the positive and negative maximum voltage range voltage difference between the operating terminal and the contact terminal 6 corresponding to the intermediate voltage range. This ensures that the transient overvoltage suppression device 3 will not arbitrarily conduct within the normal voltage fluctuation range, thereby avoiding unnecessary interference with the normal operation of the system. In the event of a transient overvoltage, if the voltage difference exceeds the positive and negative maximum voltage range voltage difference between the operating terminal and the contact terminal 6 corresponding to the intermediate voltage range, the transient overvoltage suppression device 3 will quickly activate, effectively channeling the energy generated by the overvoltage, thereby protecting the electrical equipment in the entire system from the impact and damage of the transient overvoltage.

[0064] The operating end is connected to a phase-correction capacitor 4, which in turn is connected to a primary-side bushing 7. By adjusting the phase relationship between current and voltage, the phase-correction capacitor 4 improves the system's power factor, reduces reactive power loss, and thus enhances the overall efficiency of the power system. Furthermore, the operating end is connected to a primary-side bushing 7 via the phase-correction capacitor 4, further establishing a complete electrical path and ensuring stable transmission and distribution of electrical energy on the primary side.

[0065] Each contact terminal 6 is connected to a current-limiting reactor 5 in a one-to-one correspondence, and different contact terminals 6 are connected to taps with different numbers of turns on the primary winding of the transformer through corresponding current-limiting reactors 5. The tap of the primary winding of the transformer away from the contact terminal 6 is connected to another primary bushing 7. Since taps with different numbers of turns on the transformer winding correspond to different voltage outputs, this connection method can accurately select the appropriate tap according to the actual voltage regulation requirements to achieve precise regulation of the transformer output voltage. The tap of the primary winding of the transformer away from the contact terminal 6 is connected to another primary bushing 7. This connection further improves the circuit structure of the primary side of the transformer, ensuring the stable flow of current on the primary side and the effective output of voltage.

[0066] The number of static contacts of the no-load transfer switch is consistent with the number of taps of the existing transformer 1 tap changer, and each winding tap contact end 6 is connected to the tap of the existing transformer 1 tap changer in sequence according to the voltage level.

[0067] Detect the secondary voltage value on the secondary side of the transformer.

[0068] According to the secondary voltage value, the action terminal is driven to connect to the contact terminal 6 corresponding to the positive correlation of the secondary voltage value.

[0069] When the secondary voltage value is low, the system will automatically control the action end to be connected to the contact terminal 6 that can reduce the number of turns of the primary side winding. According to the transformer transformation ratio principle, this can increase the output voltage of the secondary side. Conversely, when the secondary voltage value is high, the action end will be connected to the contact terminal 6 that can increase the number of turns of the primary side winding, thereby reducing the output voltage of the secondary side, thereby realizing dynamic and precise adjustment of the transformer output voltage, ensuring that the output voltage is always stable within a reasonable range, and meeting the normal operation requirements of various electrical equipment.

[0070] Assume that a transformer tap changer has five taps, each corresponding to a different number of primary winding turns. The number of turns increases from tap 1 to tap 5.

[0071] At a certain moment, the secondary voltage value of the transformer secondary side is detected to be 370V, which is lower than the normal operating voltage range (usually the standard voltage for industrial electricity is 380V-400V). At this time, according to the above voltage regulation method, the system detects that the secondary voltage value is low and automatically controls the action end to be connected to the contact end 6 that can reduce the number of turns of the primary winding. Assuming that the current action end is connected to tap 3, the corresponding number of turns of the primary winding is N3. In order to increase the secondary voltage, the system switches the action end to tap 2. The number of turns of the primary winding corresponding to tap 2 is N2, and N2 <N3。

[0072] According to the transformer transformation ratio principle, the transformation ratio formula is K = U2 / U1 = N2 / N1, where U1 is the primary voltage, U2 is the secondary voltage, N1 is the number of primary winding turns, and N2 is the number of secondary winding turns. While the primary voltage U1 remains unchanged, when the number of primary winding turns decreases from N3 to N2, the secondary voltage U2 increases accordingly. Actual measurements show that after the switch, the secondary voltage rises to 385V, meeting the normal operating voltage requirements of most industrial equipment.

[0073] Some time later, due to the shutdown of large industrial equipment, the power load dropped significantly, and the secondary voltage rose to 410V. The system detected the voltage anomaly again and determined that the secondary voltage was high. At this point, the system switched from the currently connected tap 2 to tap 3, which increases the number of turns on the primary winding. By increasing the number of turns on the primary winding, the secondary voltage decreases according to the principle of transformation ratio. Re-measurement of the secondary voltage revealed that it had dropped to 390V, returning to a reasonable voltage range. This ensured stable operation of the industrial equipment and prevented potential damage from excessive voltage.

[0074] By detecting the transformer's secondary voltage and adjusting the contact terminal 6 connected to the operating end of the no-load tap-changer 2 accordingly, the number of primary winding turns can be adjusted in real time, thereby stabilizing the secondary output voltage. When the secondary voltage is low, the number of primary winding turns is reduced, increasing the secondary voltage based on the transformer's transformation ratio principle. When the secondary voltage is high, the number of primary winding turns is increased to reduce the secondary voltage, keeping the output voltage within a reasonable range. This effectively addresses the problem of unstable power supply caused by voltage fluctuations and ensures the normal operation of user electrical equipment. The transient overvoltage suppression device 3 installed on the no-load tap-changer 2 prevents damage to equipment caused by transient overvoltages generated during tap-changer operation. Its conduction voltage is greater than the difference between the maximum positive and negative voltage ranges between the operating end and the corresponding intermediate voltage contact terminal 6. It conducts only when a transient overvoltage occurs, limiting overvoltages to a safe range. This protects the transformer, tap-changer, and other related electrical equipment, extends equipment life, and improves system reliability. The phase correction capacitor 4 connected to the operating end improves the phase relationship of the circuit. During the operation of the transformer, by adjusting the phase of current and voltage, the power factor can be improved, reactive power loss can be reduced, and the efficiency of power transmission can be improved, making the operation of the entire power system more economical and efficient. The current-limiting inductor 5 connected to each contact terminal 6 can effectively limit the circulating current between the windings when different contact terminals 6 are connected to taps with different turns of the primary winding of the transformer. Circulating current will increase equipment loss and affect equipment life. The current-limiting inductor 5 controls the circulating current at a safe level through its own reactance characteristics, reduces the adverse effects of circulating current on the equipment, and ensures the safety and stability of the on-load voltage regulation process. According to the secondary voltage value, the action end is accurately driven to connect to different contact terminals 6, realizing fine-grained regulation of the transformer output voltage. This voltage regulation method can be flexibly adjusted according to actual voltage requirements. Compared with traditional voltage regulation methods, it can more accurately meet the voltage requirements of different users and electrical equipment, improve the power supply quality, and reduce the risk of damage to electrical equipment caused by excessive voltage deviation.

[0075] Reference Figure 2 , the method further comprises the steps of:

[0076] The transient overvoltage suppression device 3 includes a plurality of silicon bidirectional diodes connected in parallel, each of which is connected in series with a conducting device 8 ; the conducting device 8 is a switching device controlled by a background control system.

[0077] In the most recent time period, the secondary fluctuation voltage value of the secondary voltage value is calculated; the secondary fluctuation voltage value reflects the change amplitude and trend of the voltage in the time period.

[0078] Determine the voltage fluctuation range within which the secondary voltage fluctuation falls. The voltage fluctuation range is pre-divided into multiple intervals, each corresponding to a different degree of voltage variation. For example, there may be a slight fluctuation range, a moderate fluctuation range, and a severe fluctuation range. By accurately determining the range within which the secondary voltage fluctuation falls, the system can take more targeted measures.

[0079] According to the voltage fluctuation range, a corresponding conductive device 8 is matched and the matched conductive device 8 is turned on. According to the determined voltage fluctuation range, the system will match a corresponding one from multiple conductive devices 8. This matching process is based on pre-set rules and algorithms, and is intended to ensure that the selected conductive device 8 can most effectively suppress transient overvoltages under the current voltage fluctuation conditions. Different voltage fluctuation ranges correspond to conductive devices 8 with different characteristics to achieve precise voltage control. The system will turn on the matched conductive device 8 and put it into working state. Once turned on, the branch composed of the silicon bidirectional diode and the conductive device 8 will begin to work, quickly suppressing transient overvoltages and limiting overvoltages to a safe range, thereby protecting transformers and other related electrical equipment from damage.

[0080] Suppose a transformer device using the aforementioned voltage regulation method is installed in the power supply system of a residential complex. During peak hours on a particular day, a large number of residents simultaneously using various electrical devices caused significant voltage fluctuations on the transformer's secondary side. The system monitored and calculated the secondary voltage value over the previous 10 minutes, determining that the secondary voltage fluctuation value was ±15V. Analysis and judgment determined that this secondary voltage fluctuation value was within the moderate fluctuation range. According to pre-set rules, the moderate fluctuation range corresponds to the conductive device 8 numbered 3. Therefore, the background control system quickly issued a command to turn on the conductive device 8 numbered 3. The branch consisting of the conductive device 8 and the corresponding silicon bidirectional diode immediately began operating, effectively suppressing the generation of transient overvoltages and gradually restoring the secondary voltage value to stability. This ensured the normal operation of the electrical devices in the residential complex and avoided equipment damage or failures that could result from excessive voltage fluctuations.

[0081] The transient overvoltage suppression device 3 utilizes multiple silicon bidirectional diodes connected in parallel, each of which is connected in series with a conduction device 8. Based on the secondary fluctuation voltage value calculated from the secondary voltage value, the corresponding conduction device 8 can be matched and turned on. This means that different silicon bidirectional diodes can be flexibly activated according to the actual voltage fluctuation situation. When the voltage fluctuation is small, the silicon bidirectional diode branch with the lower conduction voltage is selected to operate, accurately suppressing transient overvoltages, preventing damage to equipment caused by excessive voltage, and protecting the safe and stable operation of the transformer and related equipment. By determining the voltage fluctuation range to which the secondary fluctuation voltage value belongs, the conduction device 8 is matched, making the voltage regulation method more adaptable to varying degrees of voltage fluctuation. When the voltage fluctuation is large, the silicon bidirectional diode branch with the higher conduction voltage is activated, ensuring that the transient overvoltage suppression device 3 can operate effectively under various complex operating conditions, ensuring reliable on-load voltage regulation under different voltage fluctuation conditions, and improving the adaptability and stability of the entire voltage regulation system. Precisely matching the conduction device 8 to suppress transient overvoltages reduces the impact of voltage fluctuations on power quality. This system avoids voltage spikes and harmonics caused by transient overvoltages, providing users with more stable and pure electricity, reducing interference with sensitive electrical equipment, ensuring the normal operation of various types of electrical equipment, and improving the user experience. Effectively suppressing transient overvoltages can reduce electrical shock to equipment such as transformers and tap changers, lowering equipment failure rates. Frequent voltage fluctuations and transient overvoltages can accelerate equipment insulation aging and damage internal components. Accurate transient overvoltage suppression can reduce equipment burdens, extend equipment life, reduce maintenance costs and replacement frequency, and improve the economic efficiency of the power system. Matching and controlling the conductive device 8 based on the secondary fluctuation voltage value demonstrates the intelligence of the voltage regulation system. This process occurs automatically, requiring no human intervention, and can quickly respond to voltage changes, enabling intelligent regulation of transient overvoltages. This makes the entire on-load tap regulation system more efficient and intelligent, meeting the needs of the automated and intelligent development of modern power systems.

[0082] In other embodiments, the method further comprises the steps of:

[0083] The transient overvoltage suppression device 3 includes a plurality of silicon bidirectional diodes connected in parallel, each of which is connected in series with a conducting device 8 ; the conducting device 8 is also a switching device controlled by the background control system.

[0084] Calculate the secondary fluctuation frequency of the secondary voltage value within the most recent time period. This frequency reflects the frequency characteristics of the voltage fluctuations during that period. For example, it may reveal whether the voltage fluctuates rapidly at a high frequency, slowly at a low frequency, or exhibits some complex frequency variation pattern.

[0085] Determine the frequency interval to which the secondary fluctuation frequency value belongs, and match the corresponding conductive device 8 according to the frequency interval to conduct. These frequency intervals are pre-divided according to the system operating characteristics and different manifestations of transient overvoltage. Different frequency intervals correspond to different types of voltage fluctuation conditions, representing voltage anomalies caused by different reasons. For example, the high-frequency interval may be related to the rapid switching action of power electronic equipment, and the low-frequency interval may be related to the voltage disturbance caused by the start or stop of large equipment. Based on the judgment result, the system accurately matches the corresponding one from the many conductive devices 8 and turns it on. This allows the silicon bidirectional diode branch connected to it to respond quickly and effectively suppress transient overvoltages in specific frequency intervals.

[0086] If the secondary fluctuation frequency value repeatedly jumps between adjacent frequency intervals in the recent time period, and the number of jumps is greater than a preset threshold, the action period of the action end is adjusted in a positive correlation with the number of jumps; the greater the number of jumps, the longer the action period; the smaller the number of jumps, the shorter the action period. The repeated jumps of the secondary fluctuation frequency value between adjacent frequency intervals indicate that the system is in an unstable voltage fluctuation state. At this time, the system adjusts the action period of the action end in a positive correlation with the number of jumps. The greater the number of jumps, the greater the degree of instability of the voltage fluctuation. To avoid frequent and unnecessary operation of the action end, thereby causing additional shock and loss to the system, the system will extend the action period of the action end accordingly; conversely, the smaller the number of jumps, the relatively low degree of instability of the voltage fluctuation, and the action period of the action end will be shortened so that it can respond more promptly to relatively stable voltage changes.

[0087] Take the power supply system of an industrial park as an example. The park houses a large number of different types of industrial equipment, each with significantly different power consumption characteristics. One weekday morning, the voltage on the transformer's secondary side fluctuated due to the frequent start-up and shutdown of some automated production lines. The system began calculating the secondary fluctuation frequency and, within 15 minutes, discovered that the secondary fluctuation frequency frequently jumped between 50-60 Hz (corresponding to one frequency range) and 60-70 Hz (an adjacent frequency range). The frequency of these jumps reached 20 times, far exceeding the preset threshold of 10. Based on this, the system adjusted the operating period of the actuator based on the positive correlation between the number of jumps, extending the originally short period from 5 seconds to 15 seconds. This prevented the actuator from frequently operating due to frequent and unstable voltage fluctuations, effectively reducing equipment wear and system interference. In the afternoon, with the adjustment of the production process, the voltage fluctuations tended to be stable, and the secondary fluctuation frequency value only jumped between adjacent frequency ranges three times within a period of time. The system accordingly shortened the action cycle to 8 seconds, allowing the action end to make necessary adjustments according to voltage changes more quickly, ensuring the stable operation of various equipment in the industrial park and improving the reliability and stability of the power supply system.

[0088] The transient overvoltage suppression device 3 uses a plurality of silicon bidirectional diodes connected in parallel, each of which is connected in series with a conductive device 8, and the conductive device 8 is matched according to the frequency interval to which the secondary fluctuation frequency value belongs. Transient overvoltages of different frequencies may be caused by different reasons, such as the switching on and off of different types of equipment in the power system, faults, etc. In this way, the corresponding silicon bidirectional diode branches can be accurately activated for transient overvoltages of different frequencies, effectively suppressing transient overvoltages, protecting transformers and related equipment from the impact of overvoltages of different frequencies, and improving the safety and stability of equipment operation. When the secondary fluctuation frequency value repeatedly jumps horizontally in adjacent frequency intervals and the number of jumps is greater than the preset threshold, the action cycle of the action end is adjusted in a positive correlation with the number of jumps. This strategy fully takes into account the complex situation of voltage fluctuations, and avoids frequent action of the action end when the voltage fluctuates frequently but has not reached a stable state. Because frequent action not only increases equipment wear, but may also cause new transient problems. The operating cycle adaptively adjusts based on the number of lateral jumps. A greater lateral jump count results in a longer operating cycle, reducing unnecessary operations; a smaller lateral jump count results in a shorter operating cycle. This allows for timely response to relatively stable voltage fluctuations and optimizes the operating strategy of the operating end, extending equipment life and improving voltage regulation efficiency. Precise transient overvoltage suppression and appropriate operating cycle adjustment reduce system interference from transient overvoltages and the potential instability caused by frequent lateral operation. The entire on-load tap-regulating system operates more stably in the face of complex voltage fluctuations, reducing the risk of system failures, improving power supply reliability, and ensuring continuous and stable power supply to users. Control based on the secondary fluctuation frequency and the number of lateral jumps enables the system to automatically adapt to varying voltage fluctuations. Removing the need for frequent manual intervention, the system makes intelligent decisions based on real-time conditions, automatically adjusting transient overvoltage suppression and the operating cycle of the operating end. This enhances the system's adaptability and intelligence, aligning with the trend of intelligent development in modern power systems and improving overall power system performance.

[0089] The action end is linked to a drive motor 9, which is controlled by a voltage regulation execution controller 10. The method includes the following steps:

[0090] The movement speed of the drive motor 9 is adjusted inversely according to the secondary voltage value; the larger the voltage value on the secondary side, the smaller the movement speed of the drive motor 9; the smaller the voltage value on the secondary side, the greater the movement speed of the drive motor 9.

[0091] When the secondary voltage is high, it means the power system's output voltage is relatively sufficient, and the drive motor 9 doesn't need to rapidly adjust the voltage. Instead, to avoid voltage instability caused by over-adjustment, the voltage control controller 10 instructs the drive motor 9 to slow down. This allows the motor to adjust at a more stable pace, ensuring that the voltage is optimized slowly within a suitable range and preventing large voltage fluctuations caused by rapid operation.

[0092] Conversely, when the secondary voltage is low, it indicates that the power system's output voltage is failing to meet actual demand, necessitating a rapid voltage increase to ensure the normal operation of various electrical devices. In this case, the voltage regulation controller 10 responds quickly, issuing an acceleration command to the drive motor 9 based on the low voltage data it detects, significantly increasing the speed of the drive motor 9. The drive motor 9 operates at high speed, driving the actuator to rapidly actuate, quickly connecting to the contact terminal 6 that reduces the number of turns on the primary winding. Based on the transformer's transformation ratio principle, this rapidly increases the secondary output voltage, allowing the voltage to quickly return to a reasonable operating range.

[0093] Take the power supply system of a commercial complex as an example. The complex covers a variety of business formats such as shopping malls, office buildings and hotels. There are many electrical equipment and the electricity demand is complex and changeable. During the lunch period on weekdays, a large number of lighting equipment, air-conditioning systems and electrical equipment of catering businesses in the mall are running at the same time. The power load rises sharply, causing the voltage value on the secondary side of the transformer to drop to 360V, which is far below the standard 380V-400V range. The voltage regulation execution controller 10 quickly captures this voltage change and immediately increases the action speed of the drive motor 9 according to the preset anti-correlation regulation rules. The drive motor 9 runs quickly, driving the action end to quickly switch to the appropriate contact end 6, reducing the number of turns of the primary side winding. After a short adjustment, the secondary side voltage quickly rebounds to 385V, meeting the normal power demand of various equipment in the commercial complex.

[0094] Late at night, most businesses and offices cease operations, significantly reducing power load and causing the transformer's secondary voltage to rise to 405V. Voltage regulator controller 10 again takes effect, reducing the speed of drive motor 9 based on the higher secondary voltage. Drive motor 9 then slowly rotates, causing the actuator to adjust gradually, increasing the number of turns on the primary winding and gradually stabilizing the secondary voltage at 390V. This prevents potential damage to equipment caused by excessive voltage and ensures stable operation of the entire commercial complex's power supply system, preparing for normal business operations the next day.

[0095] When the secondary voltage is low, the drive motor 9 operates rapidly, quickly connecting the actuating end to the contact terminal 6 that reduces the number of turns on the primary winding, thereby rapidly increasing the secondary voltage. Conversely, when the secondary voltage is high, the drive motor 9 operates more slowly, allowing the actuating end to slowly adjust to the contact terminal 6 that increases the number of turns on the primary winding, thus preventing over-regulation of the voltage. This method of adjusting the actuating speed in real time based on the voltage value allows the voltage regulation process to more quickly approach the target voltage value, reducing voltage regulation time. It also effectively prevents excessive or inadequate voltage regulation, significantly improving the efficiency and accuracy of voltage regulation, ensuring that the output voltage remains stable within a reasonable range, and safeguarding the normal operation of the user's electrical equipment. The actuating speed of the drive motor 9 is inversely correlated with the secondary voltage value, preventing the motor from operating at high speed when not necessary. When the voltage deviation is small, the motor operates at a low speed, reducing wear on the motor and related transmission components, and lowering mechanical losses in the equipment. Furthermore, the reduced motor speed also means reduced energy consumption, which helps extend the life of the equipment, reduce maintenance costs, and improve the economic efficiency of the entire on-load voltage regulation system. When voltage fluctuates significantly, the motor operates quickly to adjust the voltage quickly. As the voltage approaches stability, the motor decelerates, ensuring a smoother voltage regulation process. This helps prevent excessive voltage fluctuations caused by rapid motor movement, which could lead to system oscillations or other instability. This adaptive speed regulation ensures stable operation of the entire on-load tap-regulation system under varying voltage conditions, improving system reliability and stability while minimizing interference with other parts of the power system.

[0096] A lightning arrester 11 is connected in parallel to the phase correction capacitor 4 .

[0097] During power system operation, various overvoltage conditions may occur, such as lightning overvoltage and operational overvoltage. The primary function of the lightning arrester 11 is to quickly conduct when an overvoltage occurs, directing the charge generated by the overvoltage into the ground, thereby limiting the voltage amplitude. When the phase correction capacitor 4 is connected in parallel with the lightning arrester 11, the lightning arrester 11 takes priority in the event of an overvoltage, preventing the overvoltage from damaging the phase correction capacitor 4. This extends the service life of the phase correction capacitor 4, ensuring it can continuously and stably improve the circuit phase relationship and maintain normal system operation. The phase correction capacitor 4 plays a key role in improving the phase relationship of the circuit and increasing the power factor. If the phase correction capacitor 4 is damaged by overvoltage, the phase characteristics of the circuit will be affected, potentially leading to problems such as a reduced power factor and increased energy loss. The parallel protection of the lightning arrester 11 ensures the normal operation of the phase correction capacitor 4, thereby ensuring the stable operation of the entire circuit, reducing system failures caused by phase problems, and improving the reliability of the power system. The protective effect of the lightning arrester 11 reduces the probability of damage to the phase correction capacitor 4, thereby reducing the frequency of equipment maintenance and replacement. This not only saves maintenance time and labor costs, but also reduces material costs associated with equipment replacement, improving the economic efficiency of power system operation and effectively controlling the maintenance costs of the entire on-load tap-changing system. Overvoltage can cause serious faults in electrical equipment, such as insulation breakdown and short circuits, posing a threat to equipment and personnel safety. The lightning arrester 11, connected in parallel with the phase-correction capacitor 4, effectively limits overvoltage, reducing the risk of electrical accidents caused by overvoltage, ensuring the safe operation of the power system, and providing more reliable safety for operators and surrounding equipment.

[0098] The inductance value of each current-limiting reactor 5 is equal, and its inductive reactance is equal to the capacitive reactance of the phase correction capacitor 4. The circulating current of the inductive reactance of each current-limiting reactor 5 at the gear voltage of the adjacent gear of the existing transformer 1 is less than 1% of the rated current; the action end can be selected to stay in the position between the two gears and simultaneously power the circuits of the two gears.

[0099] The voltage regulation controller 10 drives a stepper motor to adjust the no-load tap changer position. The current-limiting reactor 5 suppresses circulating current, and the phase-correction capacitor 4 offsets its reactance to the load current, eliminating the need for complex technologies to achieve live voltage regulation. Simultaneously, a silicon bidirectional diode suppresses transient overvoltages, and the impedance matching characteristics of the inductive-capacitive three-port circuit enable simultaneous power supply to two taps, creating a tap position multiplier and achieving a smooth voltage regulation ratio of 1.25%.

[0100] The inductance value of each current-limiting reactor 5 is equal, and the circulating current generated by its inductive reactance under the gear voltage of the adjacent gear of the existing transformer 1 is less than 1% of the rated current. During the transformer voltage regulation process, there is a potential difference between different gears, which is prone to generate circulating current. Excessive circulating current will not only increase power loss, but may also damage the equipment. This design of the current-limiting reactor 5 can limit the circulating current to an extremely low level, ensuring the stability and safety of the transformer during the voltage regulation process, and reducing the risk of failure caused by circulating current. The use of silicon bidirectional diodes can effectively suppress transient overvoltages. During the transformer voltage regulation process, especially at the moment of gear switching, transient overvoltages are easily generated, which may cause damage to the equipment. Silicon bidirectional diodes can quickly turn on when overvoltage occurs, discharge the overvoltage energy, protect the insulation performance of the transformer and related equipment, and extend the service life of the equipment.

[0101] The capacitive reactance of the phase correction capacitor 4 is equal to the inductive reactance of the current limiting reactor 5, which can offset the reactance effect of the current limiting reactor 5 on the load current. While suppressing the circulating current, the current limiting reactor 5 will produce a certain reactance effect on the load current, affecting the efficiency of power transmission. The addition of the phase correction capacitor 4 optimizes the impedance characteristics of the circuit, improves the power factor, reduces reactive power loss, and improves the operating efficiency of the entire power system. Utilizing the impedance matching characteristics of the inductive-capacitive three-port circuit, it is possible to power two taps at the same time. This characteristic allows the action end to stay between the two gears, powering the circuits of the two gears at the same time, achieving a more flexible voltage regulation method. Through reasonable impedance matching, the stability and balance of the two taps when powering are ensured, avoiding equipment damage or voltage fluctuations caused by uneven power supply.

[0102] The operating end can remain between two positions and simultaneously power both circuits, creating the effect of doubling the tap positions. Traditional transformers have fixed tap positions and a limited adjustment range. This innovative approach effectively doubles the number of adjustment positions on top of the existing ones, significantly expanding the voltage regulation range and enabling more precise adaptation to the voltage requirements of different loads. This achieves a smooth voltage regulation ratio of 1.25%. Compared to the larger voltage regulation steps of traditional transformers, this solution enables finer voltage regulation and smoother voltage changes. This is of great significance for loads with high voltage stability requirements, such as precision electronic equipment, as it can effectively reduce the impact of voltage fluctuations on equipment and improve its operational stability and reliability.

[0103] The inductive-capacitive three-port circuit contains inductors and capacitors. Its impedance matching properties enable the impedances of different ports to be matched under specific conditions. In the voltage-regulating device of the present invention, the parameters of the current-limiting reactor 5 (inductor) and the phase-correction capacitor 4 (capacitor) are carefully designed, enabling the inductive-capacitive three-port circuit to play a key role in the transformer voltage regulation process. For example, the inductance of each current-limiting reactor 5 is equal, and its inductive reactance is equal to the capacitive reactance of the phase-correction capacitor 4. This parameter matching lays the foundation for implementing subsequent functions. When switching between gears, the traditional no-load tap changer 2 can only connect to a fixed static contact at the operating end, meaning that only one tap is currently supplying power. However, the impedance matching properties of the inductive-capacitive three-port circuit change this situation. During the voltage regulation process, the operating end can remain between the static contacts corresponding to the two gears. In this case, the winding taps connected to these two static contacts are simultaneously powered through the synergistic effect of components such as the current-limiting reactor 5 and the phase-correction capacitor 4. For example, when the operating end is between gears 1 and 2, the corresponding winding taps 1 and 2 can simultaneously power the circuit. This power supply method breaks the traditional single-tap power supply model. Since the operating end can stay between two gears and simultaneously power both taps, an adjustable intermediate state is added between two adjacent gears (assuming each gear has a voltage adjustment of 2.5%). This is equivalent to doubling the number of gears in the existing gear system. For example, instead of the limited gears 1, 2, and 3, adjustable intermediate gears are now added between gears 1 and 2, and between gears 2 and 3, thereby doubling the number of tap positions. In traditional tap changers, the voltage adjustment range for each gear is 2.5%, which can result in large abrupt changes in voltage regulation, which may cause users to notice phenomena such as light flickering. By doubling the number of tap positions, the present invention splits the original 2.5% voltage adjustment range into two. For example, when the operating terminal is midway between two gears, supplying power through both taps simultaneously can achieve a 1.25% voltage regulation, making the voltage regulation process smoother. Furthermore, the inductive-capacitive three-port circuit's regulation of current and voltage effectively reduces voltage fluctuations and sudden changes when switching between gears, further improving the smoothness of voltage regulation, ensuring power quality, and reducing users' perception of voltage changes during electricity use.

[0104] The method further comprises the steps of:

[0105] When the action is performed at the action end, the magnetic field change data on the primary side is obtained through the magnetic field detection device.

[0106] Spectral analysis is performed on the magnetic field change data to obtain the magnetic field change data under the frequency domain signal; in the time domain, the magnetic field change data may present a complex and disordered fluctuation pattern, but after spectral analysis, the proportion and role of different frequency components in the magnetic field change can be clearly seen.

[0107] Calculate the amplitude and phase of the magnetic field change data under the frequency domain signal; the amplitude reflects the intensity of each frequency component in the magnetic field change, while the phase represents the relative time relationship between different frequency components.

[0108] Spectral features are extracted based on amplitude and phase. These features include peak frequency bands and frequency band energy distribution. Peak frequency bands are the frequency ranges with the largest amplitudes in the spectrum. They often correspond to the most significant frequency components in magnetic field variations and may be related to the operating status of specific electrical equipment or interference sources. Frequency band energy distribution describes the distribution of energy within different frequency bands. By analyzing the energy distribution, we can understand the importance and contribution of each frequency component in magnetic field variations.

[0109] The spectrum features are normalized to obtain corresponding eigenvalues; the normalization process converts spectrum features of different amplitudes and ranges into comparable eigenvalues.

[0110] Based on the normalized eigenvalues, the system matches a corresponding silicon bidirectional diode from multiple diodes and turns it on. Different eigenvalues ​​represent different magnetic field variations, which means different types of transient overvoltages may exist. Each silicon bidirectional diode has specific conduction characteristics that can effectively suppress different transient overvoltages. By precisely matching the eigenvalues ​​with the silicon bidirectional diodes, the system can achieve targeted suppression of transient overvoltages, greatly improving the effectiveness and efficiency of overvoltage suppression.

[0111] Take the power supply system of a large factory as an example. The factory contains a large number of power electronic devices, such as inverters and rectifiers, which generate complex electromagnetic interference during operation. When a large motor starts up, the actuator adjusts the transformer's output voltage accordingly. At this point, the system begins acquiring magnetic field variation data on the primary side and performing spectrum analysis. This analysis reveals that the amplitude of the magnetic field variation data exhibits a significant peak in the 500Hz-600Hz frequency band, and the energy distribution in this frequency band accounts for a significant proportion of the total energy. After calculating the amplitude and phase of this frequency band, the system extracts the corresponding spectral features and normalizes them to obtain a specific eigenvalue. Based on pre-defined matching rules, the system quickly matches the corresponding silicon bidirectional diode and turns it on. This silicon bidirectional diode effectively suppresses transient overvoltages in the 500Hz-600Hz frequency band, protecting the factory's electrical equipment from overvoltage damage and ensuring normal production.

[0112] When the action terminal performs an action, real-time magnetic field change data on the primary side is acquired and spectral analysis is performed. Actions on the action terminal are often accompanied by changes in voltage and current, which may trigger transient overvoltages. Magnetic field change data can reflect the dynamic changes in these electrical parameters. Spectral analysis converts the time-domain signal into a frequency-domain signal, allowing for clearer observation of the changing characteristics of different frequency components. The amplitude and phase of the magnetic field change data in the frequency domain are calculated, and spectral features, including peak frequency bands and frequency band energy distribution, are extracted. These features are then normalized to obtain eigenvalues. Different types of transient overvoltages exhibit distinct spectral characteristics, such as specific peak frequency bands and energy distribution. By matching the eigenvalues ​​to the corresponding silicon bidirectional diode conduction, the appropriate silicon bidirectional diode can be precisely selected for suppression based on the specific characteristics of the transient overvoltage, improving the targeted and effective nature of transient overvoltage suppression.

[0113] This method can rapidly respond to transient overvoltages that may occur when the operating terminal is actuated. Once the spectral signature of the magnetic field change data is detected, the corresponding silicon bidirectional diode is quickly matched and turned on based on the signature value, dissipating the overvoltage energy in a timely manner. This prevents damage to the transformer and related equipment, effectively protecting the equipment's insulation performance and normal operation, and extending its service life. Because the spectral signature reflects the specific circumstances of the transient overvoltage, this method possesses adaptive protection capabilities. Regardless of the cause of the transient overvoltage (e.g., lightning strike, operation), and how its frequency, amplitude, and other characteristics vary, spectrum analysis and signature matching can identify the most appropriate silicon bidirectional diode to turn on, achieving comprehensive and reliable protection for the equipment.

[0114] Precisely suppressing transient overvoltages can reduce the disruption they cause to power systems. Transient overvoltages can cause voltage fluctuations, increased harmonics, and other issues, impacting power system stability and power quality. Effectively suppressing transient overvoltages can reduce the impact of these disruptions on the system, ensuring stable operation of the power system, improving power quality, and providing users with a higher-quality power supply. Better equipment protection and reduced system operational disruptions contribute to improved overall power system reliability. This reduces equipment failures and system anomalies caused by transient overvoltages, lowers the risk of power outages, improves power system reliability, and meets user demands for a continuous and stable power supply.

[0115] After calculating the amplitude and phase of the magnetic field change data under the frequency domain signal, the method further includes the following steps:

[0116] A signal within a first characteristic frequency band is extracted from the magnetic field change data under the frequency domain signal.

[0117] The first discrete coefficient is calculated as the discrete degree of the amplitude of all frequency points within the first characteristic frequency band.

[0118] If the first discrete coefficient is greater than a preset first threshold, the execution speed of the action end is adjusted in anti-correlation according to the first discrete coefficient.

[0119] When the dispersion (first dispersion coefficient) of the amplitude values ​​at all frequency points within the first characteristic frequency band (high frequency band) exceeds a preset first threshold, it indicates that the magnetic field in the high frequency band is fluctuating rapidly and is unstable. Specifically, when spectrum analysis shows large fluctuations in the high frequency band, it typically indicates the presence of a high number of high-frequency harmonics in the power grid, which may be caused by rapidly varying loads (such as power electronics and switching power supplies). High-frequency harmonics can cause rapid fluctuations in voltage and current, impacting transformers and tap changers. In this case, the operating speed of the actuating terminal should be appropriately reduced. A slower execution speed can minimize the interaction between the tap changer and the high-frequency harmonics, lowering the magnitude of transient overvoltages and inrush currents caused by rapid switching, and protecting equipment from damage. For example, in industrial plants, where a large number of devices such as frequency converters generate high-frequency harmonics, the tap changer's operating speed can be set to a lower setting to avoid abnormalities during switching.

[0120] A signal within a second characteristic frequency band is extracted from the magnetic field change data under the frequency domain signal.

[0121] The discrete degree of the amplitude of all frequency points within the second characteristic frequency band is calculated as the second discrete coefficient.

[0122] If the second discrete coefficient is greater than a preset second threshold, the execution speed of the action end is adjusted according to the positive correlation of the second discrete coefficient; wherein the values ​​within the first characteristic frequency band are all greater than the values ​​within the second characteristic frequency band.

[0123] When the dispersion (second dispersion coefficient) of the amplitudes at all frequency points within the second characteristic frequency band (low frequency band) exceeds the preset second threshold, it indicates significant fluctuations in the magnetic field within the low frequency band. In other words, when spectrum analysis reveals significant fluctuations in the low frequency band, it may be related to low-frequency oscillations in the power grid or the switching on and off of large loads. Low-frequency oscillations can cause periodic fluctuations in the voltage and power of the power grid. If the operating terminal executes too quickly, switching may occur at unfavorable times during voltage fluctuations, resulting in poor voltage regulation or equipment damage. The operating terminal's execution speed can be appropriately increased. Faster tap changer operation allows the tap changer to quickly adapt to low-frequency fluctuations in the power grid, adjusting the transformer's ratio in a timely manner and stabilizing the output voltage. For example, when a large motor starts, it can cause a low-frequency drop in the power grid voltage. In this case, fast tap changer operation can promptly boost the voltage and ensure power supply quality.

[0124] This solution adaptively adjusts the execution speed of the actuator based on the changing magnetic field characteristics of different frequency bands. When the high frequency band is unstable, the speed is reduced to avoid over-regulation; when anomalies occur in the low frequency band, the speed is increased to accelerate the regulation process. This adaptive regulation method ensures that the actuator's actions are more consistent with the actual system operation, enabling more precise voltage regulation, improving efficiency and accuracy, and ensuring the stability and reliability of the system's output voltage. By separately processing and adjusting different frequency bands, system changes can be more accurately captured, reducing regulation errors caused by frequency interference. Using different regulation strategies for high and low frequency bands avoids inaccurate regulation caused by a single regulation method unable to adapt to complex frequency variations, resulting in more optimal voltage regulation. Properly adjusting the execution speed of the actuator can reduce system losses. Reducing the speed when anomalies occur in the high frequency band reduces unnecessary rapid action by the actuator, reducing mechanical wear and energy consumption. Increasing the speed when anomalies occur in the low frequency band quickly stabilizes the system and reduces energy loss caused by low-frequency oscillations. By optimizing the execution speed, the system's energy efficiency is improved and operating costs are reduced. This solution monitors and adjusts magnetic field variations across different frequency bands, enhancing the system's anti-interference capabilities. Whether it's high- or low-frequency interference, the system can promptly adjust the execution speed of the action end based on the frequency band characteristics, effectively suppressing the impact of interference on the system. This improves system reliability and stability, enabling the system to operate normally even in complex electromagnetic environments.

[0125] In addition, in other embodiments, the voltage and load harmonic characteristics are different in different power consumption periods. In order to further optimize the timing of voltage regulation, the timing of voltage regulation is selected in combination with the voltage and load harmonic period characteristics:

[0126] Peak hours: During peak electricity consumption periods, the grid is heavily loaded, voltage may drop, and the load generates complex harmonics. If spectrum analysis reveals significant fluctuations in certain frequency bands associated with voltage drops, actions can be performed when voltage fluctuations are relatively flat. For example, if analysis reveals that fluctuations in a low-frequency band coincide with a voltage drop, tap changers can be switched when the frequency fluctuations are minimal, i.e., when the voltage is relatively stable, to ensure effective voltage regulation and equipment safety.

[0127] Off-peak hours: During off-peak hours, when electricity consumption is low and the grid load is light, voltage may rise. The harmonic content in the spectrum during these hours differs from that during peak hours. If significant fluctuations in a specific frequency band are observed and correlated with voltage increases, appropriate action can be taken. For example, high-frequency harmonics are relatively reduced during off-peak hours, but some low-frequency voltage fluctuations may still exist. Tap changers can be adjusted when the voltage reaches a certain level and is about to stabilize, avoiding over-regulation and minimizing harmonic interference.

[0128] For example, a commercial district in a certain city includes numerous shopping malls, restaurants, and office buildings. Between 6:00 PM and 9:00 PM on weekdays (peak period), a large number of lighting, air conditioning, and catering equipment operate simultaneously, dramatically increasing the grid load. Spectrum analysis shows that the second dispersion coefficient in the low-frequency band (5-20 Hz) exceeds the preset second threshold, indicating the presence of low-frequency oscillations associated with voltage drops. Based on this information, the system increases the speed of the operating terminal, quickly triggering tap changers and adjusting the transformer ratio, stabilizing the voltage and ensuring normal power supply to the commercial district. Furthermore, the first dispersion coefficient in the high-frequency band (500-1000 Hz) is also high during this period, so the system reduces the speed of the operating terminal to prevent equipment damage caused by the interaction between high-frequency interference and rapid operation. However, between 2:00 AM and 5:00 AM (off-peak period), the power load decreases significantly, and the voltage tends to rise. Spectrum analysis revealed some fluctuations in the low-frequency band (10-30 Hz). When the voltage rose to a near-stable value, the system adjusted the tap changer to avoid over-voltage regulation, effectively maintaining voltage stability, reducing harmonic interference, and ensuring efficient and stable operation of the power system in the entire commercial area.

[0129] An embodiment of the present application further discloses an on-load voltage regulation device based on an existing transformer, comprising a processor, wherein the processor executes the steps of any one of the above-mentioned on-load voltage regulation methods based on an existing transformer.

[0130] An embodiment of the present application further discloses a storage medium, in which a program is stored. When the program is executed by a processor, the steps of any one of the above-mentioned on-load voltage regulation methods based on an existing transformer are implemented.

[0131] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for on-load voltage regulation based on an existing transformer, characterized in that: The invention comprises the following steps: a transient overvoltage suppression device (3) is provided on a no-load voltage-regulating tap-changer (2); one end of the transient overvoltage suppression device (3) is connected to the action end of the no-load voltage-regulating tap-changer (2); the other end is connected to the contact end (6) corresponding to the intermediate gear voltage in the no-load voltage-regulating tap-changer (2); the conduction voltage of the transient overvoltage suppression device (3) is greater than the positive and negative maximum voltage gear voltage difference between the action end and the contact end (6) corresponding to the intermediate gear voltage; the action end is connected to a primary side bushing (7) through a phase correction capacitor (4); each contact end (6) is correspondingly connected to a current-limiting reactor (5 ), different contact terminals (6) are connected to taps with different numbers of turns on the winding of the primary side of the transformer; the tap of the transformer primary side coil away from the contact terminal (6) is connected to another primary side bushing (7); the secondary voltage value of the transformer secondary side is detected; according to the secondary voltage value, the action terminal is driven to be connected to the contact terminal (6) corresponding to the positive correlation of the secondary voltage value; the transient overvoltage suppression device (3) includes a plurality of parallel silicon bidirectional diodes, each silicon bidirectional diode is connected in series with a conduction device (8); wherein each silicon bidirectional diode has a specific conduction characteristic and can effectively suppress different transient overvoltages; calculating a secondary fluctuation voltage value of the secondary voltage value within a recent time period; Determining the voltage fluctuation range to which the secondary fluctuation voltage value belongs; Matching a corresponding conducting device (8) according to the voltage fluctuation range; Turning on the matched conducting device (8); or, calculating a secondary fluctuation frequency value of the secondary voltage value within a recent time period; Determining the frequency interval to which the secondary fluctuation frequency value belongs, and matching a corresponding conducting device (8) according to the frequency interval to conduct the conduction; If, in a recent time period, the secondary fluctuation frequency value repeatedly jumps between adjacent frequency intervals, and the number of jumps is greater than a preset threshold, the action period of the action end is adjusted in a positive correlation with the number of jumps; The greater the number of traverse jumps, the longer the action cycle; the smaller the number of traverse jumps, the shorter the action cycle; or, when the action end performs the action, obtaining the magnetic field change data of the primary side; Performing spectrum analysis on the magnetic field change data to obtain magnetic field change data in frequency domain signals; Calculate the amplitude and phase of the magnetic field change data under the frequency domain signal; Extracting spectrum features based on amplitude and phase, wherein the spectrum features include peak frequency band and frequency band energy distribution; Normalizing the frequency spectrum features to obtain corresponding eigenvalues; Matching a corresponding silicon bidirectional diode according to the characteristic value; The matched silicon bidirectional diode is turned on.

2. The on-load voltage regulation method based on an existing transformer according to claim 1, characterized in that: The action end is linked with a drive motor (9), and the method comprises the following steps: adjusting the movement speed of the driving motor (9) according to the anti-correlation of the secondary voltage value; The greater the voltage value on the secondary side, the lower the movement speed of the drive motor (9); and the smaller the voltage value on the secondary side, the greater the movement speed of the drive motor (9).

3. The on-load voltage regulation method based on an existing transformer according to claim 2, characterized in that: The phase correction capacitor (4) is connected in parallel with a lightning arrester (11).

4. The on-load voltage regulation method based on an existing transformer according to claim 3, characterized in that: The inductance value of each current-limiting reactor (5) is equal, and its inductive reactance is equal to the capacitive reactance of the phase correction capacitor (4). The circulating current of the inductive reactance of each current-limiting reactor (5) under the gear voltage of the adjacent gear of the existing transformer (1) is less than 1% of the rated current; the action end can be selected to stay in the position between the two gears and simultaneously supply power to the circuits of the two gears.

5. The on-load voltage regulation method based on an existing transformer according to claim 1, characterized in that: After calculating the amplitude and phase of the magnetic field change data under the frequency domain signal, the method further includes the following steps: Extracting a signal within a first characteristic frequency band from the magnetic field change data under the frequency domain signal; Calculating the dispersion degree of the amplitudes of all frequency points within the first characteristic frequency band as a first dispersion coefficient; If the first discrete coefficient is greater than a preset first threshold, adjusting the execution speed of the action end in an anti-correlation manner according to the first discrete coefficient; Extracting a signal within a second characteristic frequency band from the magnetic field change data under the frequency domain signal; Calculating the dispersion degree of the amplitudes of all frequency points within the second characteristic frequency band as a second dispersion coefficient; If the second discrete coefficient is greater than a preset second threshold, adjusting the execution speed of the action end according to the positive correlation of the second discrete coefficient; The values ​​within the first characteristic frequency band are all greater than the values ​​within the second characteristic frequency band.

6. An on-load tap-changing device based on an existing transformer, characterized in that: The method comprises a processor, wherein the processor executes the steps of the on-load voltage regulation method based on an existing transformer as claimed in any one of claims 1 to 5.

7. A storage medium, characterized in that: The medium stores a program, and when the program is executed by the processor, the steps of the on-load voltage regulation method based on an existing transformer according to any one of claims 1 to 5 are implemented.

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