Transformer no-load closing angle control method, electronic equipment, storage medium and program product

Abstract

The embodiment of the invention provides a transformer no-load closing angle control method, electronic equipment, a storage medium and a program product. The method comprises the following steps: periodically sampling three-phase voltages at a power supply side of a transformer, and determining a zero crossing moment when the phase voltage is changed from a negative value to a positive value according to respective sampling data for each phase in the three phases; based on the zero point moment of each phase, a preset switching-on angle and the total delay required from the switching-on instruction sending to the actual conduction of the main circuit, the target moments at which the switching-on instructions of the three phases should be sent out are calculated respectively, and corresponding switching-on trigger signals are output at the target moments of the phases respectively; and in response to the closing trigger signal of each phase, combined switch circuits arranged in the three-phase line are respectively driven, and each group of combined switch circuit comprises an MOS (Metal Oxide Semiconductor) tube and a dry reed relay which are connected in parallel, so that the MOS tube is conducted to establish an initial current path.

Description

Technical Field

[0001] This application relates to the field of power system automation and intelligent switch control technology, and in particular to a control method, electronic equipment, storage medium and program product for a transformer no-load closing angle. Background Technology

[0002] In power systems, transformers, as critical transmission and transformation equipment, inevitably undergo no-load closing operations. When a circuit breaker closes at any phase of the voltage, a sudden change in the core magnetic flux may generate an inrush current several to ten times the rated current. This inrush current may not only cause relay protection malfunctions but also impact transformer windings, circuit breaker contacts, and system stability, severely affecting the safe operation of the power grid in some cases.

[0003] Currently, the suppression of inrush current mainly employs phase-selective closing technology, which involves detecting the voltage phase and triggering the switch at a preset closing angle (e.g., 90° peak voltage). Existing technologies typically rely on zero-crossing voltage detection, combined with the preset angle and system delay to calculate the timing of the closing command, and then execute the closing through a mechanical circuit breaker or solid-state switch. However, traditional mechanical circuit breakers suffer from large operational dispersion and slow response, making it difficult to meet microsecond-level accuracy requirements; while pure solid-state switches (such as IGBTs and MOSFETs) offer fast response, they must withstand the entire inrush current at the moment of conduction, making them susceptible to damage due to overcurrent or overheating, resulting in insufficient reliability.

[0004] How to ensure the accuracy of closing angle control while taking into account the fast response capability and long-term operational reliability of switching devices, and avoid control failure due to device damage, has become a problem to be solved. Summary of the Invention

[0005] This application provides a method, electronic equipment, storage medium, and program product for controlling the no-load closing angle of a transformer, in order to ensure the accuracy of the closing angle control while taking into account the fast response capability and long-term operational reliability of the switching devices, and to avoid control failure due to device damage.

[0006] In a first aspect, embodiments of this application provide a transformer closing control method, comprising: periodically sampling the three-phase voltages on the power supply side of the transformer; for each of the three phases, determining the time when the voltage of that phase changes from negative to positive based on its respective sampling data; calculating the target time when the closing command should be issued for each of the three phases based on the zero-point time of each phase, a preset closing angle, and the total delay required from issuing the closing command to the actual conduction of the main circuit; and outputting a corresponding closing trigger signal at the target time of each phase; and driving the combined switching circuits set in the three-phase line in response to the closing trigger signals of each phase, wherein each combined switching circuit includes a MOSFET and a reed relay connected in parallel, so that the MOSFET is turned on first to establish an initial current path.

[0007] In one possible implementation, two adjacent voltage sampling points are identified, wherein the voltage value of the previous sampling point is less than zero and the voltage value of the subsequent sampling point is greater than zero; based on the voltage values ​​of the two sampling points and their corresponding sampling times, the time point when the phase voltage crosses zero is estimated by linear interpolation.

[0008] In one possible implementation, for each phase, based on its zero point and a preset closing angle, the time offset corresponding to the electrical angle required for the phase voltage to reach the closing angle is determined;

[0009] Subtract the total delay required for the phase from issuing the closing command to the actual conduction of the main circuit from the time offset to obtain the initial command time; if the initial command time is earlier than the current system time, add one or more complete voltage cycles to the initial command time to obtain the final target time; at the final target time, output the closing trigger signal of the corresponding phase.

[0010] In one possible implementation, the bidirectional conduction branch consisting of a thyristor and a diode, which cooperates with the combined switching circuit in each phase line, is triggered.

[0011] In one possible implementation, each of the three phases of the circuit is equipped with an air switch; the method further includes simulating short-circuit or ground fault conditions by controlling the opening and closing states of the air switches.

[0012] In one possible implementation, the total delay includes the time required for the control device to process the closing command and the time required for the corresponding phase switch actuator to close its contacts after receiving the signal.

[0013] Secondly, embodiments of this application provide a transformer closing control device, comprising: a sampling module, used to periodically sample the three-phase voltages on the power supply side of the transformer, and for each of the three phases, determine the time when the voltage of that phase crosses zero when it changes from a negative value to a positive value based on its respective sampling data; an output module, used to calculate the target time when the closing command of each of the three phases should be issued based on the zero-point time of each phase, a preset closing angle, and the total delay required from issuing the closing command to the actual conduction of the main circuit, and output the corresponding closing trigger signal at the target time of each phase; and a response module, used to respond to the closing trigger signal of each phase, and drive the combined switching circuits set in the three-phase line respectively, wherein each group of combined switching circuits includes a MOSFET and a reed relay connected in parallel, so that the MOSFET is turned on first to establish an initial current path.

[0014] Thirdly, embodiments of this application provide a transformer closing control device, including: a memory and a processor;

[0015] The memory stores computer-executed instructions;

[0016] The processor executes computer execution instructions stored in the memory, causing the processor to perform the first aspect and / or various possible implementations of the first aspect as described above.

[0017] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the first aspect and / or various possible implementations of the first aspect.

[0018] Fifthly, embodiments of this application provide a computer program product, including a computer program that, when executed by a processor, implements the first aspect and / or various possible implementations of the first aspect.

[0019] The transformer no-load closing angle control method, electronic equipment, storage medium, and program product provided in this application achieve high-precision control of the closing angle through phase-by-phase sampling, independent calculation, and coordinated operation of combined switches. By utilizing the fast conduction characteristics of MOSFETs and the steady-state carrying capacity of reed relays, the vulnerability of solid-state switches is effectively solved. Furthermore, by combining bidirectional conduction branches, the adaptability of the system in complex potential environments is improved, achieving the effect of ensuring the accuracy of closing angle control while taking into account the fast response capability and long-term operational reliability of switching devices, and avoiding control failure due to device damage. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0021] Figure 1 Flowchart of the transformer closing control method provided in this application Figure 1 ;

[0022] Figure 2 Flowchart of the transformer closing control method provided in this application Figure 2 ;

[0023] Figure 3 The single-phase circuit diagram of the combined switch circuit provided in this application;

[0024] Figure 4 A schematic diagram of the closing control device for the transformer provided in this application;

[0025] Figure 5 This is a schematic diagram of the closing control device for the transformer provided in this application.

[0026] The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0027] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0028] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will be described below with reference to the accompanying drawings.

[0029] Figure 1 Flowchart of the transformer closing control method provided in this application Figure 1 ,like Figure 1 As shown, the method includes:

[0030] S201. Periodically sample the three-phase voltages on the power supply side of the transformer. For each of the three phases, determine the moment when the voltage of that phase crosses zero when it changes from a negative value to a positive value based on its respective sampling data.

[0031] The power supply side of a transformer refers to the side of the transformer, either the high-voltage side or the low-voltage side, that is connected to the power grid. It is usually the controlled end for closing operations.

[0032] Three-phase voltage refers to the AC voltage signals of phases A, B, and C in a power system, with a phase difference of 120° between them.

[0033] Periodic sampling involves digitizing analog voltage signals at fixed time intervals (such as every millisecond or higher) using an analog-to-digital converter (ADC).

[0034] The moment of crossing zero refers to the point in time when the sinusoidal voltage waveform transitions from the negative half-cycle to the positive half-cycle and its instantaneous value is zero. It is also called the "positive zero-crossing point" and is the reference point for calculating the voltage phase angle.

[0035] This step first synchronously acquires real-time voltage waveform data for phases A, B, and C. For each phase, the system continuously monitors its continuous sample values. When a sample value is detected to be less than zero and the next sample value is greater than zero, it is determined that the voltage has crossed zero from negative to positive within that sampling interval. Subsequently, based on the voltage values ​​of these two adjacent sampling points and their corresponding timestamps, numerical methods such as linear interpolation are used to estimate the precise time point of the actual zero-crossing of the phase voltage. This process is executed independently for the three phases, thereby obtaining three independent zero-point moments, which serve as the time reference for subsequent phase-by-phase closing control.

[0036] S202. Based on the zero point time of each phase, the preset closing angle, and the total delay required from issuing the closing command to the actual conduction of the main circuit, calculate the target time when the closing command of each of the three phases should be issued, and output the corresponding closing trigger signal at the target time of each phase.

[0037] The preset closing angle, the target closing phase angle set by the user or control system (such as 90°), indicates the desired electrical angle position of the voltage waveform at which closing is to be completed. It is usually selected near the voltage peak to minimize the flux change.

[0038] Total delay refers to the total time delay from when the controller issues the closing command until the main contacts of the combination switch are actually turned on and the current is established. This includes the control logic processing time, drive circuit response time, MOSFET turn-on time, and reed relay mechanical action time.

[0039] The closing trigger signal is a digital or pulse signal output by the controller, used to start the combined switch drive circuit of the corresponding phase.

[0040] After obtaining the zero-point time of each phase, the system calculates the time offset (i.e., θ / 360° × voltage period) required for the phase voltage to reach the target phase based on the preset closing angle (e.g., θ = 90°). Then, the total delay of the phase path is subtracted from this time offset to obtain the initial closing command issuance time. If this time is earlier than the current system time, one or more complete voltage periods (e.g., 20 ms / 50 Hz) are added to ensure that the command is executed at a future time. Finally, the system generates and outputs independent closing trigger signals at the calculated target time for each phase, achieving precise three-phase time-sharing and phase-by-phase control.

[0041] S203 responds to the closing trigger signal of each phase and drives the combined switch circuits set in the three-phase line respectively. Each group of combined switch circuits includes a MOSFET and a reed relay connected in parallel, so that the MOSFET is turned on first to establish an initial current path.

[0042] A combination switch circuit is a hybrid switch structure consisting of semiconductor devices and electromagnetic devices connected in parallel, which combines fast response and high current withstand capability.

[0043] MOSFETs, or metal-oxide-semiconductor field-effect transistors, have switching speeds in the nanosecond to microsecond range, making them suitable for rapid turn-on, but their continuous current carrying capacity is limited.

[0044] A reed relay is a type of sealed electromagnetic relay whose contacts close under the influence of a magnetic field. It can carry large currents and has a low on-state voltage, but its operating time is usually in the millisecond range.

[0045] The initial current path refers to the temporary current path established at the moment of closing, which is used to maintain circuit continuity before the main switch is fully closed.

[0046] When the closing trigger signal for a phase arrives, the corresponding drive circuit first quickly turns on the MOSFET in that phase. Because the MOSFET responds extremely quickly, a current path can be established within microseconds, ensuring the closing action is completed near the target phase angle. Subsequently, within a set time window after the MOSFET turns on (e.g., 1–5 ms), the control system energizes the coil of the reed relay, causing its mechanical contacts to close. The closed reed relay, connected in parallel with the MOSFET, bears most of the steady-state load current, thus "unloading" the MOSFET from high-current conditions and preventing it from being damaged by continuous heating. This collaborative mechanism achieves the dual advantages of "fast turn-on + strong load-bearing capacity".

[0047] The transformer closing control method provided in this application achieves high-precision control of the closing angle through phase sampling, independent calculation, and coordinated action of combined switches. By utilizing the fast conduction characteristics of MOSFETs and the steady-state carrying capacity of reed relays, the problem of vulnerability of solid-state switches is effectively solved. Furthermore, by combining bidirectional conduction branches, the adaptability of the system in complex potential environments is improved, achieving the effect of ensuring the accuracy of closing angle control while taking into account the fast response capability and long-term operational reliability of switching devices, and avoiding control failure due to device damage.

[0048] Figure 2 Flowchart of the transformer closing control method provided in this application Figure 2 ,like Figure 2 As shown, in this embodiment... Figure 1 Based on the embodiments, the transformer closing control method is described in detail, which includes:

[0049] S301. Identify two adjacent voltage sampling points; based on the voltage values ​​of the two sampling points and their corresponding sampling times, estimate the zero-crossing time of the phase voltage using linear interpolation.

[0050] The voltage value at the previous sampling point is less than zero, and the voltage value at the next sampling point is greater than zero.

[0051] Adjacent voltage sampling points refer to two voltage data points that are collected consecutively in time, with no other sampling interval between them. They are usually acquired by an analog-to-digital converter (ADC) at a fixed sampling period.

[0052] A voltage value less than zero or greater than zero indicates that the instantaneous AC voltage value is in the negative or positive half-cycle, with the system reference ground as the reference.

[0053] Linear interpolation is a numerical estimation method that assumes a linear relationship between voltage changes between two sampling points, and uses this to estimate the precise moment when the voltage is zero.

[0054] The zero-crossing point refers to the instant when the phase voltage waveform crosses the zero level from negative to positive, and serves as the starting reference for calculating the closing phase angle.

[0055] During the periodic sampling of a phase voltage, the system continuously monitors the continuous sampling sequence. When a negative (i.e., less than zero) voltage value is detected at a certain sampling point, and the voltage value of the next sampling point that follows is positive (i.e., greater than zero), it is determined that a zero-crossing from negative to positive has occurred in the voltage waveform between the two sampling points.

[0056] Subsequently, the system acquires the specific values ​​of these two adjacent sampling points (denoted as U<0 and U>0) and their corresponding sampling times (denoted as tbefore and tafter). Based on the principle of linear interpolation, assuming that the voltage between the two points changes linearly with time, the time t0 when the voltage is zero can be estimated through a proportional relationship.

[0057] The estimated result is the high-resolution time point at which the phase voltage crosses zero in the positive direction, which is used for the accurate timing calculation of the subsequent closing angle.

[0058] In one embodiment, assuming the voltage at the previous sampling point is Uk−1<0 and the sampling time is tk−1, and the voltage at the next sampling point is Uk>0 and the sampling time is tk, then the zero-crossing time t0 of the phase voltage can be estimated using the following linear interpolation formula:

[0059]

[0060] S302. For each phase, based on its zero point time and preset closing angle, determine the time offset corresponding to the electrical angle required for the phase voltage to reach the closing angle; subtract the total delay required for the phase from issuing the closing command to the actual conduction of the main circuit from the time offset to obtain the initial command time; if the initial command time is earlier than the current system time, add one or more complete voltage cycles to the initial command time to obtain the final target time; at the final target time, output the closing trigger signal of the corresponding phase.

[0061] Zero point refers to the precise time point at which the phase voltage changes from a negative value to a positive value and crosses the zero level, serving as the starting reference for phase calculation.

[0062] The preset closing angle, or the target closing electrical angle set by the user or control system (such as 0°, 90°, 180°, etc.), indicates the desired phase position of the voltage waveform at which the closing operation is to be completed.

[0063] In a power frequency AC system, the time offset corresponding to an electrical angle is a fixed time length (e.g., 20 milliseconds for a 50 Hz system). Therefore, any closing angle can be converted into the length of time that needs to be waited from the zero point.

[0064] Total delay refers to the total delay from the time the controller issues the closing command until the combination switch completes conduction and the main circuit truly establishes a current path, including the total time for control processing, drive response, MOSFET turn-on, and reed relay operation.

[0065] A complete voltage cycle refers to the time required for an AC voltage to complete one sine wave cycle (e.g., 20 ms for 50 Hz and approximately 16.67 ms for 60 Hz).

[0066] For each of the three phases, the system first takes the zero point time calculated by itself as the starting point, and determines the time length required for the voltage waveform to rise from the zero point to the target phase according to the preset closing angle, that is, the time offset corresponding to the electrical angle.

[0067] The system then subtracts the total delay corresponding to that phase path from the time offset to obtain a preliminary closing command issuance time. This preliminary time indicates that if the command is issued at this moment, the main circuit will accurately conduct at the target phase angle after considering all delays.

[0068] However, if the initial command time is earlier than the current system real-time (i.e., belongs to a past time), it cannot be executed. In this case, the system automatically adds one or more complete voltage cycles (e.g., 20 ms, 40 ms, etc.) to the initial time until the resulting time is after the current time, thereby determining the final target time of the closing command.

[0069] Finally, at the final target time calculated by each phase, the system generates and outputs the corresponding closing trigger signal to drive the subsequent combined switching action.

[0070] In one embodiment, let the zero-point time of a certain phase be t0, the preset closing angle be θ (unit: degrees), the system voltage period be Tcycle (e.g., Tcycle = 20ms in a 50 Hz system), and the total delay be Td, then the initial command time tpre is,

[0071]

[0072] If tpre ≤ tcurrent (current system time), then the final target time tcmd is,

[0073]

[0074] Where N is the smallest non-negative integer that satisfies tcmd>tcurrent.

[0075] S303 triggers the bidirectional conducting branch composed of thyristors and diodes that cooperates with the combined switch S circuit in each phase line.

[0076] A combination switch circuit refers to a main switching unit composed of a MOSFET and a reed relay connected in parallel, used to achieve coordinated fast turn-on and steady-state load carrying, such as... Figure 3 As shown, Figure 3 The single-phase circuit diagram of the combined switch circuit provided in this application.

[0077] A silicon controlled rectifier (SCR) is a semiconductor switching device that has unidirectional conduction characteristics, but can be bidirectionally controlled by reverse parallel connection or in conjunction with a diode.

[0078] A diode is an electronic component that conducts electricity in one direction. Here it is used in conjunction with a silicon controlled rectifier (SCR) to create a bidirectional conduction path.

[0079] A bidirectional conduction branch, consisting of a pair of anti-parallel thyristors or a thyristor and a diode connected in anti-parallel, can achieve controlled conduction during both the positive and negative half-cycles of the AC voltage.

[0080] After the combined switching circuits of each phase have completed the conduction operation (i.e., the MOSFET has been turned on and the reed relay has been closed), the control system further outputs a trigger signal to the bidirectional conduction branch of that phase. This branch is usually composed of a thyristor and a diode connected in reverse parallel, or two thyristors connected in reverse parallel, to support the bidirectional flow of alternating current.

[0081] When the branch receives a trigger signal, its internal thyristor is turned on, thereby establishing a low-impedance auxiliary current path across the switch. The function of this branch is to ensure reliable circuit connection even if there is residual voltage, induced electromotive force, or asymmetrical potential difference across the combination switch, preventing closing failure due to poor contact or arcing.

[0082] The triggering operation can be executed immediately after the reed relay closes, or it can be delayed depending on the system status. The specific timing is determined by the controller according to the preset logic.

[0083] In one embodiment, each of the three phases of the circuit is equipped with an air switch; the method further includes simulating short-circuit or ground fault conditions by controlling the opening and closing states of the air switches. For example, during the experimental testing phase, the air switch of a certain phase can be manually or automatically disconnected to simulate an open circuit, or its output terminal can be short-circuited to ground to simulate a single-phase ground fault, thereby verifying the response performance and safety of the closing control method under abnormal conditions.

[0084] In another embodiment, the total delay includes the time required for the control device to process the closing command and the time required for the corresponding phase switch actuator to close its contacts after receiving the signal. The control device processing time includes delays in closing angle calculation, command generation, and signal output; the switch actuator's action time includes MOSFET drive delays, reed relay mechanical response time, etc. This total delay can be obtained through offline calibration or online self-learning and stored in the controller's parameter table for accurate compensation of the closing timing.

[0085] The transformer closing control method provided in this application achieves high-precision control of the closing angle through phase sampling, independent calculation, and coordinated action of combined switches. By utilizing the fast conduction characteristics of MOSFETs and the steady-state carrying capacity of reed relays, the problem of vulnerability of solid-state switches is effectively solved. Furthermore, by combining bidirectional conduction branches, the adaptability of the system in complex potential environments is improved, achieving the effect of ensuring the accuracy of closing angle control while taking into account the fast response capability and long-term operational reliability of switching devices, and avoiding control failure due to device damage.

[0086] Figure 4 A schematic diagram of the closing control device for the transformer provided in this application is shown below. Figure 4 As shown, the transformer closing control device 40 provided in this embodiment includes:

[0087] The sampling module 401 is used to periodically sample the three-phase voltage on the power supply side of the transformer. For each of the three phases, the sampling data is used to determine the time when the voltage of that phase changes from negative to positive and crosses zero.

[0088] The output module 402 is used to calculate the target time when the closing command of each of the three phases should be issued based on the zero point time of each phase, the preset closing angle, and the total delay required from the issuance of the closing command to the actual conduction of the main circuit, and to output the corresponding closing trigger signal at the target time of each phase.

[0089] The response module 403 is used to respond to the closing trigger signal of each phase and drive the combined switch circuits set in the three-phase line respectively. Each group of combined switch circuits includes a MOSFET and a reed relay connected in parallel, so that the MOSFET is turned on first to establish an initial current path.

[0090] In one possible implementation, the sampling module 401 is used to identify two adjacent voltage sampling points, wherein the voltage value of the previous sampling point is less than zero and the voltage value of the subsequent sampling point is greater than zero; based on the voltage values ​​of the two sampling points and their corresponding sampling times, the time point when the phase voltage crosses zero is estimated by linear interpolation.

[0091] In one possible implementation, the output module 402 is used to determine, for each phase, the time offset corresponding to the electrical angle required for the phase voltage to reach the closing angle based on its zero point time and a preset closing angle; subtract the total delay required for the phase from issuing the closing command to the actual conduction of the main circuit from the time offset to obtain the initial command time; if the initial command time is earlier than the current system time, add one or more complete voltage cycles to the initial command time to obtain the final target time; and output the closing trigger signal of the corresponding phase at the final target time.

[0092] In one possible implementation, the response module 403 is used to trigger the bidirectional conduction branch in each phase line that is in cooperation with the combined switch circuit and consists of a thyristor and a diode.

[0093] In one possible implementation, the above-mentioned device further includes: a simulation module (not shown in the figure) for configuring air switches in the three-phase lines respectively; the method further includes: simulating short circuit or ground fault conditions by controlling the opening and closing state of the air switches.

[0094] In one possible implementation, the total delay in the above-described device includes the time required for the control device to process the closing command and the time required for the corresponding phase switch actuator to close its contacts after receiving the signal.

[0095] The transformer closing control device provided in this embodiment can execute the method provided in the above method embodiment. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0096] Figure 5 This is a schematic diagram of the closing control device for the transformer provided in this application. Figure 5 As shown, the electronic device 50 provided in this embodiment includes at least one processor 501 and a memory 502. Optionally, the device 50 further includes a communication component 503. The processor 501, memory 502, and communication component 503 are connected via a bus 504.

[0097] In a specific implementation, at least one processor 501 executes computer execution instructions stored in memory 502, causing at least one processor 501 to perform the above-described method.

[0098] The specific implementation process of processor 501 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0099] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0100] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0101] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0102] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0103] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0104] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0105] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0106] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0107] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0108] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0109] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0110] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0111] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A method for controlling the no-load closing angle of a transformer, characterized in that, include: The three-phase voltages on the power supply side of the transformer are periodically sampled. For each of the three phases, the moment when the voltage of that phase crosses zero when it changes from a negative value to a positive value is determined based on its respective sampling data. Based on the zero point time of each phase, the preset closing angle, and the total delay required from issuing the closing command to the actual conduction of the main circuit, the target time when the closing command of each of the three phases should be issued is calculated, and the corresponding closing trigger signal is output at the target time of each phase. In response to the closing trigger signal of each phase, the combined switching circuits set in the three-phase line are driven respectively. Each group of combined switching circuits includes a MOSFET and a reed relay connected in parallel, so that the MOSFET is turned on first to establish an initial current path.

2. The method according to claim 1, characterized in that, For each phase, determine the moment when its voltage crosses zero as it changes from negative to positive, including: Identify two adjacent voltage sampling points, where the voltage value of the first sampling point is less than zero and the voltage value of the second sampling point is greater than zero; Based on the voltage values ​​of the two adjacent voltage sampling points and their corresponding sampling times, the time point when the phase voltage crosses zero is estimated by linear interpolation.

3. The method according to claim 1, characterized in that, Calculate the target time when the closing command for each of the three phases should be issued, and output the corresponding closing trigger signal at the target time for each phase, including: For each phase, based on its zero point and preset closing angle, determine the time offset corresponding to the electrical angle required for the phase voltage to reach the closing angle; Subtracting the total delay required for the phase from the issuance of the closing command to the actual conduction of the main circuit from the time offset yields the initial command issuance time. If the initial command time is earlier than the current system time, then one or more complete voltage cycles are added to the initial command time to obtain the final target time; At the final target time, the corresponding phase closing trigger signal is output.

4. The method according to claim 1, characterized in that, After responding to the closing trigger signals of each phase and driving the combined switching circuits installed in the three-phase lines respectively, the method further includes: Trigger the bidirectional conduction branch composed of thyristors and diodes in each phase line that cooperates with the combined switch circuit.

5. The method according to any one of claims 1-4, characterized in that, Each of the three phases is equipped with an air switch; the method further includes simulating short circuit or ground fault conditions by controlling the opening and closing state of the air switches.

6. The method according to any one of claims 1-4, characterized in that, The total delay includes the time required for the control device to process the closing command and the time required for the corresponding phase switch actuator to close its contacts after receiving the signal.

7. A transformer closing control device, characterized in that, include: The sampling module is used to periodically sample the three-phase voltage on the power supply side of the transformer. For each of the three phases, it determines the moment when the voltage of that phase crosses zero when it changes from a negative value to a positive value based on its respective sampling data. The output module is used to calculate the target time when the closing command should be issued for each of the three phases based on the zero point time of each phase, the preset closing angle, and the total delay required from issuing the closing command to the actual conduction of the main circuit, and to output the corresponding closing trigger signal at the target time of each phase. The response module is used to respond to the closing trigger signal of each phase and drive the combined switching circuits set in the three-phase line respectively. Each group of combined switching circuits includes a MOSFET and a reed relay connected in parallel, so that the MOSFET is turned on first to establish an initial current path.

8. A transformer closing control device, characterized in that, include: Memory, processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the processor to perform the method as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-6.

10. A computer program product, characterized in that, Includes a computer program that, when executed by a processor, implements the method described in any one of claims 1-6.

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