Voltage distortion improvement apparatus, method, and computer readable storage medium

Abstract

The application provides a voltage distortion improvement device, comprising at least one control module and one instruction output module. The control module is used for capturing the phase angle of the switching-off voltage of the short-circuit transformer at the low-voltage side during the i-th switching-off, setting the phase angle of the switching-off voltage of the short-circuit transformer at the low-voltage side during the i-th switching-off as the phase angle of the switching-on voltage of the short-circuit transformer at the low-voltage side during the i+1-th switching-on, and setting the i+1-th switching-on instruction and the i+1-th switching-off instruction of the phase-selective switching-on switch. The i+1-th switching-off instruction is used for improving the voltage distortion generated during the i+2-th switching-on. The application also provides a voltage distortion improvement method. Based on the above scheme, the voltage distortion caused by the switching-on of the phase-selective switching-on switch at the high-voltage side can be solved.

Description

Technical Field

[0001] This invention relates to the field of electrical technology, and in particular to a device, method, and computer-readable storage medium for improving voltage distortion. Background Technology

[0002] When using a high-voltage side phase-selective closing switch for short-circuit testing, the test voltage waveform is often distorted due to the residual magnetism of the short-circuit transformer. Standard IEC60947-1:2020 Clause 9.3.4.1.2C stipulates that when using a high-voltage side switch for closing, the test station needs to prove that the voltage waveform will not be distorted under the influence of the residual magnetism of the short-circuit transformer.

[0003] To cover the test voltage range of low-voltage electrical products, short-circuit test transformers typically have more taps on the high-voltage side, meaning more adjustment ranges. For example, a short-circuit transformer might have 25 taps on the high-voltage side, as shown in Figure 1. The figure illustrates the connection methods for taps 1 and 25. Clearly, in tap 1, all high-voltage windings are connected in series; as the tap increases, fewer windings are connected in series. According to the formula... In the formula, U1 is the primary voltage, f is the voltage frequency, N1 is the number of turns in the winding, and Φ is the voltage frequency. m - The maximum value of the main magnetic flux and the primary voltage U1 are relatively constant. When testing at a low setting, the number of coil turns N1 is more, so the maximum value of the main magnetic flux Φ is higher. m The lower the value, the less likely the magnetic circuit will saturate. Conversely, when testing at a higher value, the magnetic circuit is more prone to saturation. Therefore, to avoid magnetic circuit saturation, testing should be performed at a lower value whenever possible. However, some test parameters can only be performed at a higher value, which may lead to magnetic flux saturation and voltage distortion problems caused by high-voltage side closing.

[0004] Therefore, how to provide a device, method, and computer-readable storage medium to improve voltage distortion and solve the voltage distortion problem caused by high-voltage side closing in the prior art has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a voltage distortion improvement device that can solve the voltage distortion caused by the closing of the high-voltage side phase-selective closing switch.

[0006] In a first aspect, the present invention provides a voltage distortion improvement device applied to a short-circuit testing device for electrical products; the short-circuit testing device includes a short-circuit transformer connected to the electrical product, a load connected to the short-circuit transformer, a phase-selective closing switch connected to the load, and a controller connected to the phase-selective closing switch; the voltage distortion improvement device includes: at least one control module connected to the short-circuit transformer and the controller, used to capture the opening voltage phase angle of the short-circuit transformer on the low-voltage side when the phase-selective closing switch opens for the i-th time, and set the opening voltage phase angle of the short-circuit transformer on the low-voltage side when the phase-selective closing switch opens for the i-th time to the phase-selective closing switch closing for the (i+1)-th time. The short-circuit transformer's closing voltage phase angle on the low-voltage side and the setting of the (i+1)th closing command and the (i+1)th opening command of the phase-selective closing switch; the (i+1)th opening command is used to improve the voltage distortion generated during the (i+2)th closing; i is a positive integer greater than or equal to 1; an instruction output module, connected to the controller, is used to output the (i+1)th closing command and the (i+1)th opening command to the controller, so that the controller controls the closing of the phase-selective closing switch according to the (i+1)th closing command and the closing voltage phase angle of the phase-selective closing switch on the low-voltage side of the short-circuit transformer during the (i+1)th closing, and controls the opening of the phase-selective closing switch according to the (i+1)th opening command.

[0007] In one possible implementation, the (i+1)th closing command is a set (i+1)th closing time; the (i+1)th opening command is a set (i+1)th opening time; the (i+1)th opening time is equal to the (i+1)th closing time, the test time, and the distortion improvement time used to subsequently improve the voltage distortion generated during the (i+2)th closing; the distortion improvement time is equal to the closing voltage phase angle of the short-circuit transformer on the low-voltage side at the (i+2)th closing time divided by the angular velocity; the closing voltage phase angle of the short-circuit transformer on the low-voltage side at the (i+2)th closing time is the closing voltage phase angle set according to the user's test requirements.

[0008] In one possible implementation, the control module is further configured to, during the initial improvement phase, set the opening voltage phase angle of the short-circuit transformer on the low-voltage side when the phase-selective closing switch opens for the first time, based on the closing voltage phase angle of the short-circuit transformer on the low-voltage side when the phase-selective closing switch opens for the first time, and generate a first closing command and a first opening command. The first closing command and the first opening command are output to the controller through the command output module, so that the controller controls the initial closing and initial opening of the phase-selective closing switch.

[0009] In one possible implementation, the closing voltage phase angle of the short-circuit transformer on the low-voltage side during the first closing is equal to the opening voltage phase angle of the short-circuit transformer on the low-voltage side during the first opening.

[0010] In one possible implementation, when the closing voltage phase angle of the short-circuit transformer on the low-voltage side is equal to the opening voltage phase angle of the short-circuit transformer on the low-voltage side when it is first opened, the transient bias magnetism and residual magnetism of the short-circuit transformer have opposite polarities. When the phase-selective closing switch (22) is opened for the i-th time, the opening voltage phase angle of the short-circuit transformer on the low-voltage side is set to the closing voltage phase angle of the short-circuit transformer on the low-voltage side when the phase-selective closing switch is closed for the (i+1)-th time, and the transient bias magnetism and residual magnetism of the short-circuit transformer have opposite polarities. The opposite polarities of the transient bias magnetism and residual magnetism of the short-circuit transformer make the resultant magnetic flux of the short-circuit transformer 21 less than the saturation magnetic flux, which can improve voltage distortion.

[0011] In one possible implementation, the system further includes a data acquisition module, located on the low-voltage side of the short-circuit transformer and connected to the control module. This module acquires voltage data of the short-circuit transformer after the phase-selective closing switch completes its first opening. The phase-selective closing switch captures the opening voltage phase angle of the short-circuit transformer on the low-voltage side during the i-th opening from the voltage data. The data acquisition module enables accurate acquisition of the opening voltage phase angle.

[0012] In one possible implementation, the instruction output module includes at least three timing generators and at least three photoelectric converters connected to the control module. Timing accuracy can be precisely controlled by using the timing transmitters.

[0013] In one possible implementation, each timing generator is connected one-to-one with each photoelectric converter to form at least three command output channels. The command output channels include a start command output channel, a close command output channel, and a close command output channel. The start command output channel consists of the electrical signal receiving end of the photoelectric converter, the optical signal transmitting end of the photoelectric converter, and the optical signal receiving end of the timing generator connected to the optical signal transmitting end of the photoelectric converter. The close command output channel / close command output channel consists of the optical signal transmitting end of the timing generator, the optical signal receiving end of the photoelectric converter connected to the optical signal transmitting end of the timing generator, and the electrical signal transmitting end of the photoelectric converter. The configuration of the start command output channel, close command output channel, and close command output channel enables precise control of the closing and opening operations.

[0014] The present invention also provides a method for improving voltage distortion, which can solve the voltage distortion caused by the closing of the high-voltage side phase-selective closing switch.

[0015] Secondly, the present invention also provides a method for improving voltage distortion, applied to a short-circuit testing device for electrical products; the short-circuit testing device includes a short-circuit transformer connected to the electrical product, a load connected to the short-circuit transformer, a phase-selective closing switch connected to the load, and a controller connected to the phase-selective closing switch; the method for improving voltage distortion includes: capturing the phase angle of the short-circuit transformer's opening voltage on the low-voltage side when the phase-selective closing switch opens for the i-th time; setting the phase angle of the short-circuit transformer's opening voltage on the low-voltage side when the phase-selective closing switch opens for the i-th time to the phase angle of the short-circuit transformer's opening voltage on the (i+1)-th time when the phase-selective closing switch closes for the (i+1)-th time. The closing voltage phase angle of the short-circuit transformer on the low-voltage side; setting the (i+1)th closing command and the (i+1)th opening command of the phase-selective closing switch, so that when the controller receives the (i+1)th closing command and the (i+1)th opening command, it controls the closing of the phase-selective closing switch according to the (i+1)th closing command and the closing voltage phase angle of the short-circuit transformer on the low-voltage side when the phase-selective closing switch closes for the (i+1)th time, and controls the opening of the phase-selective closing switch according to the (i+1)th opening command; the (i+1)th opening command is used to improve the voltage distortion generated during the (i+2)th closing; i is a positive integer greater than 1.

[0016] Thirdly, the present invention also provides a computer-readable storage medium storing computer-readable instructions, which, when executed by a processor, cause the processor to perform the steps of the voltage distortion improvement method as described in any one of claims 1 to 8. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the high-voltage side tap of the short-circuit test transformer provided by existing technology;

[0018] Figure 2 It is a diagram showing the relationship between the hysteresis loop of the transformer core and the magnetic field strength and steady-state magnetic flux.

[0019] Figure 3 It is the primary voltage u1 and the steady-state magnetic flux Φ s Relationship diagram.

[0020] Figure 4 It is a diagram showing the relationship between primary voltage, steady-state magnetic flux, bias magnetism, residual magnetism, and opening and closing angles.

[0021] Figure 5 This is a schematic diagram of an exemplary voltage distortion improvement device provided in an embodiment of this application.

[0022] List of reference numerals in the attached diagram:

[0023] 1 Electrical appliances

[0024] 2. Short-circuit test device

[0025] 20 load

[0026] 21 Short-circuit transformer

[0027] 22 Phase-selective closing switch

[0028] 23 Controller

[0029] 3. Voltage distortion correction device

[0030] 31 Control Module

[0031] 32. Instruction Output Module

[0032] 33 Data Acquisition Module

[0033] 321 Timing Generator

[0034] 322 photoelectric converter Detailed Implementation

[0035] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the following will be combined with this application.

[0036] The accompanying drawings in the embodiments clearly and in detail describe the technical solutions in the embodiments of this application. Obviously, the described embodiments are only some embodiments of the embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art should fall within the protection scope of the embodiments of this application.

[0037] It should be understood that the terms "first," "second," and "third," etc., in the claims, specification, and drawings of this disclosure are used to distinguish different objects, not to describe a specific order. The terms "comprising" and "including" as used in the specification and claims of this disclosure indicate the presence of the described features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or sets thereof.

[0038] It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this disclosure. As used in this disclosure and claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this disclosure and claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0039] The specific implementation of the embodiments of this application will be further described below with reference to the accompanying drawings.

[0040] The voltage distortion improvement device in this embodiment utilizes the following technical principle: At the instant the transformer is switched on, the total magnetic flux Φ is synthesized from three parts: the residual magnetism Φres, the bias magnetism Φp, and the steady-state magnetic flux Φs. When the polarity of the bias magnetism and the residual magnetism are the same, the synthesized total magnetic flux Φ = Φres + Φp + Φs, and the total magnetic flux is greater than the saturation magnetic flux. When the polarity of the bias magnetism and the residual magnetism are opposite, the synthesized total magnetic flux Φ = Φp - Φres + Φs, and the total magnetic flux is less than the saturation magnetic flux. Therefore, as long as the polarity of the residual magnetism and the bias magnetism are opposite, the total magnetic flux in the transformer core at the instant of switching on can be suppressed, thereby solving the voltage distortion problem caused by high-voltage side switching on. The magnetic circuit will not saturate, thus solving the voltage distortion problem caused by high-voltage side switching on. The theoretical basis of this technical principle is as follows:

[0041] First, determine the polarity of the transient bias Φp. The process for determining the polarity of the transient bias Φp is as follows:

[0042] The voltage equation of the primary winding of a single-phase transformer under no-load operation is as follows:

[0043]

[0044] In the formula, N1 and z1 are the number of turns and leakage impedance of the primary winding, respectively. Since the leakage impedance voltage drop caused by the transformer's no-load current is very small, typically less than 0.2% of U1, i1z1 can be neglected.

[0045]

[0046] Solving the differential equation (1.2), we obtain the expression for the magnetic flux Φ as follows:

[0047]

[0048] According to the law of conservation of flux linkage, the magnetic flux Φ is 0 at the instant of closing (ignoring residual magnetism), and the instant of closing t=0, we can obtain

[0049]

[0050] Therefore, equation (1.3) can be written as

[0051]

[0052] because Equation (1.5) can be written as

[0053] Φ=Φ m [cosα-cos(ωt+α)]

[0054] =Φ mcosα-Φ m cos(ωt+α)

[0055] =Φ p -Φ s In equation (1.6), Φ p =Φ m cosα is the bias magnetism, and Φ is at the moment of closing. p The value of Φ is related to the closing angle α. When closing at 90° or 270°, p =0, Φ when closing at 0° or 180° p Reaching peak value Φ m ;Φ s =Φ m cos(ωt+α) is the steady-state magnetic flux, a one-periodic function. At the instant of closing the switch, the total magnetic flux is 0 (ignoring residual magnetism), so Φ p =Φ s The bias magnetism generated when a transformer is energized under no-load conditions is equal in magnitude but opposite in polarity to the steady-state magnetic flux at the moment of closing. The primary voltage leads the steady-state magnetic flux by 90°. Therefore, by controlling the closing voltage angle, the polarity and magnitude of the transient bias magnetism can be controlled.

[0056] Next, the polarity of the remanent magnetization Φres is determined. The process for determining the polarity of the remanent magnetization Φres is as follows:

[0057] Figure 2 This diagram shows the relationship between the hysteresis loop, magnetic field strength, and steady-state magnetic flux of a transformer core. After applying an AC excitation voltage to the primary winding of the transformer, the magnetic field strength H ranges from -H... m ~+H m The magnetic flux within the iron core varies periodically along the hysteresis loop under the influence of the magnetic field strength. The magnetic field strength H is in phase with the transformer's no-load current I0 and slightly leads the steady-state Φ. s Angle α, where α is the iron loss angle. At any moment on the magnetic field strength curve 4-5-6-7, if the primary voltage is removed, the remanent magnetization of the iron core is negative; at any moment on the magnetic field strength curve 7-8-9-10, if the primary voltage is removed, the remanent magnetization of the iron core is positive or zero. The time interval of the magnetic field strength curve 4-5-6-7 corresponds to the steady-state magnetic flux Φ. s The negative half-cycles coincide, and the time interval of the magnetic field intensity curve 7-8-9-10 coincides with the steady-state magnetic flux Φ. s The positive half-cycles coincide. That is, in the steady-state magnetic flux Φ s When the excitation voltage is cut off during the positive half-cycle, the residual magnetism of the iron core is positive or 0, and the steady-state magnetic flux Φ s When the excitation voltage is cut off during the negative half-cycle, the residual magnetism of the iron core becomes negative.

[0058] Figure 3 For the primary voltage u1 and steady-state magnetic flux Φ s Relationship diagram, u1 ahead of Φs The phase is 90°. By controlling the voltage switching angle, the polarity of the residual magnetism in the iron core can be controlled. Figure 3 At time t1, the primary voltage is cut off, and the opening voltage angle is 0°. At this time, the corresponding steady-state magnetic flux is at its negative maximum value, and the polarity of the residual magnetism is negative, as shown by curve A.

[0059] Finally, the method of suppressing residual magnetism by using bias magnetism is employed.

[0060] Figure 4 This diagram shows the relationship between primary voltage, steady-state magnetic flux, bias magnetism, residual magnetism, and the opening and closing angles. At time t1, the circuit is opened, and the opening angle α' is recorded (α' = 0°). The polarity and magnitude of the residual magnetism are obtained, as shown by line B in the diagram. At time t2, the circuit is closed, making the closing angle α equal to the opening angle α'. The polarity and magnitude of the bias magnetism are then obtained, as shown by line C in the diagram. The diagram shows that when the closing angle equals the opening angle, the bias magnetism and residual magnetism have opposite polarities, resulting in a resultant magnetic flux Φ less than the saturation magnetic flux Φ. sat The magnetic circuit will not saturate, thus avoiding distortion of the secondary voltage.

[0061] Based on the above technical theory, this embodiment provides a voltage distortion improvement device, which is applied to, for example... Figure 5 The short-circuit testing device 2 for the electrical product 1 shown. The short-circuit testing device 2, used to perform short-circuit testing on the electrical product 1, includes a short-circuit transformer 21 connected to the electrical product 1, a load 20 connected to the short-circuit transformer 21, a phase-selective closing switch 22 connected to the load 20, and a controller 23 connected to the phase-selective closing switch 22. A voltage distortion improvement device 3 is used to resolve the voltage distortion caused by the closing of the phase-selective closing switch 22 on the high-voltage side of the short-circuit testing device 2.

[0062] Please continue reading. Figure 5 The voltage distortion correction device 3 includes at least one control module 31, one command output module 32, and a data acquisition module 33. The control module 31 is connected to the short-circuit transformer 21 and the controller 23. The command output module 32 is connected to the controller 23. The command output module 32 includes at least three timing generators 321 and at least three photoelectric converters 322 connected to the control module 31. Each timing generator 321 is connected to each photoelectric converter 322 in a one-to-one correspondence to form at least three command output channels. The command output channels include a start command output channel, a closing command output channel, and a opening command output channel. The configuration of the start command output channel, closing command output channel, and opening command output channel enables precise control of the opening and closing operations.

[0063] The start command output channel consists of the electrical signal receiving end of the photoelectric converter 322, the optical signal transmitting end of the photoelectric converter 322, and the optical signal receiving end of the timing generator 321 connected to the optical signal transmitting end of the photoelectric converter 322. The closing command output channel / the opening command output channel consists of the optical signal transmitting end of the timing generator 321, the optical signal receiving end of the photoelectric converter 322 connected to the optical signal transmitting end of the timing generator 321, and the electrical signal transmitting end of the photoelectric converter 322. In practical applications, by using the timing transmitter 321, the time accuracy can be controlled to 0.1ms, i.e., 1.8° electrical angle.

[0064] In practical applications, the control module 31 can be a host computer or, for example, a host computer. Figure 5 The three host computers shown respectively perform the functions of capturing voltage, setting the opening and closing voltage phase angles, and generating closing and opening commands. Improving voltage distortion through the host computers is simple, effective, and saves a significant amount of time.

[0065] The data acquisition module 33 is located on the low-voltage side of the short-circuit transformer 21 and is connected to the control module 31, for example, a host computer. The data acquisition module 33 can accurately acquire the phase angle of the trip voltage.

[0066] The control module 31, during the initial improvement phase, sets the opening voltage phase angle of the short-circuit transformer 21 on the low-voltage side when the phase-selective closing switch 22 first closes, based on the closing voltage phase angle of the short-circuit transformer 21 on the low-voltage side during the first closing of the phase-selective closing switch 22, and generates the first closing command and the first opening command. The closing voltage phase angle of the short-circuit transformer 21 on the low-voltage side during the first closing of the phase-selective closing switch 22 is a test requirement. The first closing command is the first closing time, and the first opening command is the first opening time. The first opening time is equal to the first closing time, the test time, and the distortion improvement time used to improve the voltage distortion generated during the second closing.

[0067] The distortion improvement time is equal to the phase angle of the opening voltage of the short-circuit transformer 21 on the low-voltage side when the phase selection closing switch 22 is opened for the first time, divided by the angular velocity.

[0068] In this embodiment, the control module 31 sets the phase angle of the short-circuit transformer 21 on the low-voltage side when the phase-selective closing switch 22 first opens to be equal to the phase angle of the short-circuit transformer 21 on the low-voltage side when the phase-selective closing switch 22 first closes. This causes the controller 23 to control the phase-selective closing switch 22 to close according to the phase angle of the short-circuit transformer 21 on the low-voltage side during the first closing, thus adjusting the magnetic field Φ at the closing moment. p and remanence Φ resThe polarities are opposite to address the voltage distortion caused by the closing of the high-voltage side phase-selective closing switch 22 of the short-circuit test device 2 during the initial improvement phase.

[0069] In this embodiment, after the control module 31 sends an electrical signal start command to the electrical signal receiving end of the photoelectric converter 322 in the start command output channel, the photoelectric converter 322 converts the electrical signal start command into an optical signal start command, and inputs the optical signal start command to the optical signal receiving end of the timing generator 321 through the optical signal transmitting end of the photoelectric converter 322, so as to trigger the timing generator 321 to start working.

[0070] The control module 31 selects the closing command output channel and sends the first closing command in the form of an optical signal to the optical signal receiving end of the photoelectric converter 322 through the optical signal transmitting end of the timing generator 321. The first closing command in the form of an optical signal is converted into the first closing command in the form of an electrical signal and output to the controller 23 through the electrical signal transmitting end of the photoelectric converter 322 so that the controller 23 can control the phase selection closing switch 22 to close.

[0071] The control module 31 selects the tripping command output channel and sends the first tripping command in the form of an optical signal to the optical signal receiving end of the photoelectric converter 322 through the optical signal transmitting end of the timing generator 321. The first tripping command in the form of an optical signal is converted into the first tripping command in the form of an electrical signal and output to the controller 23 through the electrical signal transmitting end of the photoelectric converter 322 so that the controller 23 can control the phase selection closing switch 22 to trip.

[0072] After the voltage distortion improvement device 3 completes the initial improvement phase, the data acquisition module 33 is used to acquire the voltage data of the short-circuit transformer 21 after the phase-selective closing switch 22 completes the first opening. The phase angle of the opening voltage of the short-circuit transformer 21 on the low-voltage side when the phase-selective closing switch 22 opens for the i-th time is captured from the voltage data.

[0073] The control module 31 is also used to cyclically improve voltage distortion.

[0074] Specifically, the control module 31 is also used to capture the opening voltage phase angle of the short-circuit transformer 21 on the low-voltage side when the phase-selective closing switch 22 opens for the i-th time, set the opening voltage phase angle of the short-circuit transformer 21 on the low-voltage side when the phase-selective closing switch 22 opens for the i-th time to be the closing voltage phase angle of the short-circuit transformer 21 on the low-voltage side when the phase-selective closing switch 22 closes for the (i+1)-th time, and set the (i+1)-th closing command and the (i+1)-th opening command of the phase-selective closing switch 22. The (i+1)-th opening command is used to improve the voltage distortion generated when the phase-selective closing switch 22 closes for the (i+2)-th time; i is a positive integer greater than or equal to 1. The voltage distortion improvement device 3 can not only solve the voltage distortion caused by the (i+1)-th closing of the phase-selective closing switch 22 on the high-voltage side.

[0075] In this embodiment, the (i+1)th closing command is the set (i+1)th closing time.

[0076] The (i+1)th trip command is the set (i+1)th trip time. The (i+1)th trip time equals the (i+1)th closing time, the test time, and the distortion improvement time used to subsequently improve the voltage distortion generated during the (i+2)th closing. The distortion improvement time equals the closing voltage phase angle of the short-circuit transformer on the low-voltage side at the (i+2)th closing time of the phase-selective closing switch divided by the angular velocity. The closing voltage phase angle of the short-circuit transformer on the low-voltage side at the (i+2)th closing time of the phase-selective closing switch is the closing voltage phase angle set according to the user's test requirements. The (i+1)th trip command can prepare for the next closing to improve voltage distortion.

[0077] For example, the second closing command is the set second closing time. The second opening command is the set second opening time. The second opening time = the second closing time + test time + distortion improvement time for subsequent improvement of voltage distortion generated during the third closing. The distortion improvement time is equal to the phase angle of the short-circuit transformer 21 on the low-voltage side when the phase-selective closing switch 22 opens for the third time, divided by the angular velocity. The phase angle of the closing voltage of the short-circuit transformer on the low-voltage side when the phase-selective closing switch closes for the third time is the closing voltage phase angle set according to the user's test requirements.

[0078] Specifically, the distortion correction time is denoted by t. When the phase-selective closing switch 22 opens for the third time, the phase angle of the opening voltage of the short-circuit transformer 21 on the low-voltage side is θ, and the angular velocity is equal to 2π divided by the power frequency voltage period T (the reciprocal of the power grid frequency). Therefore,

[0079]

[0080] The instruction output module 32 is also used to output the (i+1)th closing instruction and the (i+1)th opening instruction to the controller 23, so that the controller 23 controls the closing of the phase-selective closing switch 22 according to the (i+1)th closing instruction and the closing voltage phase angle of the short-circuit transformer 21 on the low-voltage side when the phase-selective closing switch 22 closes for the (i+1)th time, and controls the opening of the phase-selective closing switch 22 according to the (i+1)th opening instruction.

[0081] Specifically, the control module 31 selects the closing command output channel and sends the (i+1)th closing command in the form of an optical signal to the optical signal receiving end of the photoelectric converter 322 through the optical signal transmitting end of the timing generator 321. The (i+1)th closing command in the form of an optical signal is converted into the (i+1)th closing command in the form of an electrical signal and output to the controller 23 through the electrical signal transmitting end of the photoelectric converter 322, so that the controller 23 controls the phase selection closing switch 22 to close.

[0082] The control module 31 selects the tripping command output channel and sends the (i+1)th tripping command in optical signal form to the optical signal receiving end of the photoelectric converter 322 through the optical signal transmitting end of the timing generator 321. The (i+1)th tripping command in optical signal form is converted into the (i+1)th tripping command in electrical signal form and output to the controller 23 through the electrical signal transmitting end of the photoelectric converter 322 so that the controller 23 controls the phase selection closing switch 22 to trip.

[0083] In this embodiment, when the phase-closing switch 22 is opened for the i-th time, the phase angle of the short-circuit transformer 21 on the low-voltage side is set to the phase angle of the closing voltage of the short-circuit transformer 21 on the low-voltage side when the phase-closing switch 22 is closed for the (i+1)-th time. The polarities of the transient bias magnetism and the residual magnetism of the short-circuit transformer 21 are opposite, and the resultant magnetic flux of the short-circuit transformer 21 is less than the saturation magnetic flux. This solves the voltage distortion caused by the closing of the phase-closing switch 22 on the high-voltage side of the (i+1)-th short-circuit test device 2.

[0084] Example 2

[0085] When the voltage distortion improvement device 3 provided by this invention is implemented using only a host computer, this embodiment also provides a voltage distortion improvement method. This voltage distortion improvement method is applied to applications such as... Figure 5 The short-circuit testing device 2 for the electrical product 1 shown. In this embodiment, the voltage distortion improvement method includes not only a phase of cyclically performing voltage distortion improvement, but also an initial improvement phase. Specifically, the voltage distortion improvement method includes the following steps:

[0086] S101, Initial Improvement Stage: Based on the closing voltage phase angle of the short-circuit transformer 21 on the low-voltage side when the phase-selective closing switch 22 is closed for the first time, the opening voltage phase angle of the short-circuit transformer 21 on the low-voltage side when the phase-selective closing switch 22 is opened for the first time is set, and the first closing command and the first opening command are generated. The first closing command and the first opening command are output to the controller 23 so that the controller 23 can control the initial closing and initial opening of the phase-selective closing switch 22.

[0087] In this embodiment, the closing voltage phase angle of the short-circuit transformer 21 on the low-voltage side during the first closing is equal to the opening voltage phase angle of the short-circuit transformer 21 on the low-voltage side during the first opening.

[0088] When the closing voltage phase angle of the short-circuit transformer 21 on the low-voltage side is equal to the opening voltage phase angle of the short-circuit transformer 21 on the low-voltage side when it is first opened, the polarity of the transient bias magnetism and the residual magnetism of the short-circuit transformer 21 are opposite, the resultant magnetic flux of the short-circuit transformer 21 is less than the saturation magnetic flux, and the initial voltage distortion is improved.

[0089] After the initial voltage distortion correction is completed, the voltage distortion correction method enters a phase of cyclically correcting voltage distortion. The voltage distortion correction method also includes:

[0090] S102, capturing the phase angle of the tripping voltage on the low-voltage side of the short-circuit transformer 21 when the phase-selective closing switch 22 trips for the i-th time. In this embodiment, i starts from 1.

[0091] S103, the phase angle of the short-circuit transformer 21 on the low-voltage side when the phase-selective closing switch 22 is opened for the i-th time is set to the phase angle of the short-circuit transformer 21 on the low-voltage side when the phase-selective closing switch 22 is closed for the (i+1)-th time, so as to solve the voltage distortion caused by the (i+1)-th closing.

[0092] S104, the (i+1)th closing command and the (i+1)th opening command of the phase-selective closing switch 22 are set so that when the controller 23 receives the (i+1)th closing command and the (i+1)th opening command, it controls the closing of the phase-selective closing switch 22 according to the (i+1)th closing command and the closing voltage phase angle of the short-circuit transformer 21 on the low-voltage side when the phase-selective closing switch 22 closes for the (i+1)th time, and controls the opening of the phase-selective closing switch 22 according to the (i+1)th opening command. The (i+1)th opening command is used to improve the voltage distortion generated during the (i+2)th closing; i is a positive integer greater than 1.

[0093] In this embodiment, the (i+1)th closing command is the set (i+1)th closing time.

[0094] The (i+1)th trip command is the set (i+1)th trip time. The (i+1)th trip time is equal to the (i+1)th closing time, the test time, and the distortion improvement time used to subsequently improve the voltage distortion generated during the (i+2)th closing. The distortion improvement time is equal to the trip voltage phase angle of the short-circuit transformer 21 on the low-voltage side when the phase-selective closing switch 22 trips during the (i+2)th trip, divided by the angular velocity. The closing voltage phase angle of the short-circuit transformer on the low-voltage side when the phase-selective closing switch 22 closes during the (i+2)th closing is the closing voltage phase angle set according to the user's test requirements.

[0095] In this embodiment, when the phase-closing switch 22 is opened for the i-th time, the phase angle of the short-circuit transformer 21 on the low-voltage side is set to the phase angle of the closing voltage of the short-circuit transformer 21 on the low-voltage side when the phase-closing switch 22 is closed for the (i+1)-th time. The polarities of the transient bias magnetism and the residual magnetism of the short-circuit transformer 21 are opposite, and the resultant magnetic flux of the short-circuit transformer 21 is less than the saturation magnetic flux. This solves the voltage distortion caused by the closing of the phase-closing switch 22 on the high-voltage side of the (i+1)-th short-circuit test device 2.

[0096] This embodiment also proposes a computer-readable medium storing computer-readable instructions, which, when executed by a processor, cause the processor to perform the steps in the voltage distortion improvement method described above.

[0097] At any possible level of technical detail, this application can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this application.

[0098] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example, (but not limited to) electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0099] The computer-readable program described herein can be downloaded from a computer-readable storage medium to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives computer-readable program instructions from the network and forwards these instructions to a computer-readable storage medium in the respective computing / processing device. The computer program instructions used to perform the operations of this application may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, integrated circuit configuration data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and procedural programming languages ​​such as "C" or similar programming languages. Computer-readable program instructions may execute entirely on a user's computer, partially on a user's computer, as a standalone software package, partially on a user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing state information from the computer-readable program instructions. This electronic circuitry can execute the computer-readable program instructions to implement various aspects of this application.

[0100] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application. The nouns and pronouns referring to persons in this patent application are not limited to specific genders.

Claims

1. A voltage distortion correction device, applied to a short-circuit testing device (2) for an electrical product (1); the short-circuit testing device (2) includes a short-circuit transformer (21) connected to the electrical product (1), a load (20) connected to the short-circuit transformer (21), a phase-selective closing switch (22) connected to the load (20), and a controller (23) connected to the phase-selective closing switch (22), characterized in that, The voltage distortion correction device includes: At least one control module (31), connected to the short-circuit transformer (21) and the controller (23), is used to capture the opening voltage phase angle of the short-circuit transformer (21) on the low-voltage side when the phase-selective closing switch (22) opens for the i-th time, set the opening voltage phase angle of the short-circuit transformer (21) on the low-voltage side when the phase-selective closing switch (22) opens for the i-th time to be the closing voltage phase angle of the short-circuit transformer (21) on the low-voltage side when the phase-selective closing switch (22) closes for the i+1-th time, and set the i+1-th closing command and the i+1-th opening command of the phase-selective closing switch (22); the i+1-th opening command is used to improve the voltage distortion generated when the i+2-th time is closed; i is a positive integer greater than or equal to 1; The (i+1)th closing command is the set (i+1)th closing time; The (i+1)th trip command is the set (i+1)th trip time; the (i+1)th trip time is equal to the (i+1)th closing time, the test time, and the distortion improvement time used to subsequently improve the voltage distortion generated during the (i+2)th closing. The distortion improvement time is equal to the closing voltage phase angle of the short-circuit transformer (21) on the low-voltage side when the phase-selective closing switch (22) is closed for the (i+2)th time, divided by the angular velocity; the closing voltage phase angle of the short-circuit transformer (21) on the low-voltage side when the phase-selective closing switch (22) is closed for the (i+2)th time, which is the closing voltage phase angle set according to the user's test requirements; An instruction output module (32) is connected to the controller (23) and is used to output the (i+1)th closing instruction and the (i+1)th opening instruction to the controller (23) so that the controller (23) controls the closing of the phase-selective closing switch (22) on the low-voltage side of the short-circuit transformer (21) according to the (i+1)th closing instruction and the phase-selective closing switch (22) at the time of the (i+1)th closing, and controls the opening of the phase-selective closing switch (22) according to the (i+1)th opening instruction.

2. The voltage distortion improvement device according to claim 1, characterized in that: The control module (31) is also used in the initial improvement stage to set the opening voltage phase angle of the short-circuit transformer (21) on the low-voltage side when the phase-selective closing switch (22) is opened for the first time, based on the closing voltage phase angle of the short-circuit transformer (21) on the low-voltage side when the phase-selective closing switch (22) is closed for the first time, and to generate the first closing command and the first opening command. The first closing command and the first opening command are output to the controller (23) through the command output module (32) so that the controller (23) can control the initial closing and initial opening of the phase-selective closing switch (22).

3. The voltage distortion improvement device according to claim 2, characterized in that: When the circuit is closed for the first time, the phase angle of the closing voltage of the short-circuit transformer (21) on the low-voltage side is equal to the phase angle of the opening voltage of the short-circuit transformer (21) on the low-voltage side when the circuit is opened for the first time.

4. The voltage distortion improvement device according to claim 2, characterized in that: When the short-circuit transformer (21) closes for the first time and the phase angle of the closing voltage on the low-voltage side is equal to the phase angle of the opening voltage on the low-voltage side when the short-circuit transformer (21) opens for the first time, the polarity of the transient bias magnetism and the residual magnetism of the short-circuit transformer (21) are opposite. When the phase-selective closing switch (22) opens for the i-th time, the phase angle of the opening voltage of the short-circuit transformer (21) on the low-voltage side is set to the phase angle of the closing voltage of the short-circuit transformer (21) on the low-voltage side when the phase-selective closing switch (22) closes for the i+1-th time. The transient bias magnetism and residual magnetism of the short-circuit transformer (21) are opposite in polarity.

5. The voltage distortion improvement device according to claim 2, characterized in that: Also includes: The data acquisition module (33) is located on the low-voltage side of the short-circuit transformer (21) and connected to the control module (31). It is used to acquire the voltage data of the short-circuit transformer (21) after the phase-selective closing switch (22) completes the first opening. The phase angle of the opening voltage of the short-circuit transformer (21) on the low-voltage side when the phase-selective closing switch (22) opens for the i-th time is captured from the voltage data.

6. The voltage distortion improvement device according to claim 2, characterized in that: The instruction output module (32) includes at least three timing generators (321) and at least three photoelectric converters (322) connected to the control module (31).

7. The voltage distortion improvement device according to claim 6, characterized in that: Each of the timing generators (321) is connected to each of the photoelectric converters (322) in a one-to-one correspondence to form at least three command output channels; the command output channels include a start command output channel, a close command output channel and a trip command output channel; The start command output channel consists of an electrical signal receiving end of the photoelectric converter (322), an optical signal transmitting end of the photoelectric converter (322), and an optical signal receiving end of a timing generator (321) connected to the optical signal transmitting end of the photoelectric converter (322). The closing command output channel / the opening command output channel is composed of the optical signal transmitting end of the timing generator (321), the optical signal receiving end of the photoelectric converter (322) connected to the optical signal transmitting end of the timing generator (321), and the electrical signal transmitting end of the photoelectric converter (322).

8. A method for improving voltage distortion, applied to a short-circuit testing device (2) for an electrical product (1); the short-circuit testing device (2) includes a short-circuit transformer (21) connected to the electrical product (1), a load (20) connected to the short-circuit transformer (21), a phase-selective closing switch (22) connected to the load (20), and a controller (23) connected to the phase-selective closing switch (22), characterized in that, The methods for improving voltage distortion include: Capture the phase angle of the short-circuit transformer (21) on the low-voltage side when the phase-selective closing switch (22) is opened for the i-th time; The phase angle of the short-circuit transformer (21) on the low-voltage side when the phase-selective closing switch (22) is opened for the i-th time is set to the phase angle of the closing voltage of the short-circuit transformer (21) on the low-voltage side when the phase-selective closing switch (22) is closed for the (i+1)-th time. The i+1th closing command and the i+1th opening command of the phase-selective closing switch (22) are set so that when the controller (23) receives the i+1th closing command and the i+1th opening command, it controls the closing of the phase-selective closing switch (22) according to the i+1th closing command and the closing voltage phase angle of the short-circuit transformer (21) on the low-voltage side when the phase-selective closing switch (22) is closed for the i+1th time, and controls the opening of the phase-selective closing switch (22) according to the i+1th opening command; the i+1th opening command is used to improve the voltage distortion generated when the phase-selective closing switch (22) is closed for the i+2th time. The (i+1)th closing command is the set (i+1)th closing time; The (i+1)th trip command is the set (i+1)th trip time; the (i+1)th trip time is equal to the (i+1)th closing time, the test time, and the distortion improvement time used to subsequently improve the voltage distortion generated during the (i+2)th closing. The distortion improvement time is equal to the closing voltage phase angle of the short-circuit transformer (21) on the low-voltage side when the phase-selective closing switch (22) is closed for the (i+2)th time, divided by the angular velocity; the closing voltage phase angle of the short-circuit transformer (21) on the low-voltage side when the phase-selective closing switch (22) is closed for the (i+2)th time, which is the closing voltage phase angle set according to the user's test requirements; i is a positive integer greater than 1.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-readable instructions that, when executed by a processor, cause the processor to perform the steps in the voltage distortion improvement method as described in claim 8.

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