Distribution transformer on-load voltage regulation tap switch simulation model construction method

Abstract

The invention provides a method for constructing a simulation model of an on-load voltage regulation tap switch of a distribution transformer, and relates to the technical field of on-load voltage regulation of the distribution transformer, and the method comprises the steps: constructing a simulation model of the distribution transformer; the on-load voltage regulation tap switch is constructed; the protection circuit is constructed; constructing the voltage regulator and the control switch; constructing a time switch control module; constructing a control module of the on-load voltage regulation tap switch; and constructing a measurement display module. Through verification of a simulation model, the technical problems in the prior art that arc light exists during voltage regulation of a traditional mechanical on-load voltage regulation transformer, oil pollution is easy to generate, the failure rate is high, the voltage regulation flexibility is low, and the response speed is low can be solved.

Description

A method for constructing a simulation model of an on-load tap changer for a distribution transformer Technical Field

[0001] This invention relates to the field of on-load tap changer technology for distribution transformers, and particularly to a method for constructing a simulation model of an on-load tap changer for distribution transformers. Background Technology

[0002] Distribution networks typically employ safer and more stable on-load tap changers to regulate voltage. The most critical component in the on-load tap changer mechanism of a distribution transformer is the on-load tap changer. Currently installed older on-load tap changers in distribution transformers are mechanically operated, which has a complex mechanical structure, generates electric arcs during operation, and is prone to burning contacts with frequent operation, hindering the development of on-load tap changer technology.

[0003] How to obtain an on-load tap-changing transformer that can operate without arcing or oil contamination during voltage regulation, has a low failure rate, high voltage regulation flexibility, fast response speed, and can prove its usability is an urgent problem to be solved in this field. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for constructing a simulation model of an on-load tap changer for a distribution transformer. The simulation model can prove that it can solve the technical problems of arcing, oil contamination, high failure rate, low tap changer flexibility, and slow response speed of traditional mechanical on-load tap changers in the prior art.

[0005] A first aspect of this invention provides a method for constructing a simulation model of an on-load tap changer for a distribution transformer, comprising:

[0006] S1: Construct a simulation model of a distribution transformer. The model includes an on-load tap changer, a tap regulator, a time-controlled switch, and a control module. The control module includes an on-load tap changer control module and a time-controlled switch control module.

[0007] S2: Construct the on-load tap changer, which includes a first winding transformer and a protection circuit, and connect the protection circuit to the first winding transformer;

[0008] S3: Construct the protection circuit, which includes a selection switch and a transition resistor, and connect the protection circuit to the transition resistor. The selection switch includes two silicon carbide N-type insulated gate bipolar transistors connected in anti-parallel.

[0009] S4: Construct the voltage regulator and the time control switch. The voltage regulator includes a second winding transformer, and the time control switch includes a third winding transformer, a switching assembly, and a load. Couple the second winding transformer with the third winding transformer, connect one end of the switching assembly to the winding of the third transformer, and connect the other end of the switching assembly to the load.

[0010] S5: Construct the time-controlled switch control module to control the on / off state of the time-controlled switch;

[0011] S6: Construct the on-load tap changer control module to control the on / off state of the protection circuit;

[0012] S7: Construct a measurement and display module to display the circuit parameters in the simulation model of the distribution transformer, the circuit parameters including voltage and / or current.

[0013] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0014] In this embodiment of the invention, a selector switch is designed based on the characteristics of silicon carbide, such as high voltage resistance, strong current carrying capacity, and considerable service life, thereby realizing arc-free switching function. By replacing the traditional tap changer and contacts with an on-load tap changer composed of an arc-free selector switch, the short-circuit current generated during the switching action of the high-voltage side winding can be reduced using resistance, preventing the selector switch from burning out and reducing the failure rate of the mechanical on-load tap-changing distribution transformer. Furthermore, the transformer and its distribution transformer containing the arc-free three-phase on-load tap-changing switch can realize multi-level adjustment, improving the switching flexibility of the distribution transformer and reducing the problems of large arc and long switching time. Through simulation model testing and analysis, it is confirmed that the model can generate no arc during voltage regulation, no oil pollution, low failure rate, high voltage regulation flexibility, and fast response speed, and proves its usability. Attached Figure Description

[0015] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0016] Figure 1 is a flowchart illustrating a method for constructing a simulation model of an on-load tap changer for a distribution transformer, as provided in an embodiment of the present invention.

[0017] Figure 2 is a schematic diagram of a simulation model of an on-load tap changer for a distribution transformer provided in an embodiment of the present invention.

[0018] Figure 3 is a schematic diagram of a simulation model of a selection switch provided in an embodiment of the present invention.

[0019] Figure 4 is a schematic diagram of a simulation model of a three-phase on-load tap-changing decomposition transformer provided in an embodiment of the present invention.

[0020] Figure 5 is a schematic diagram of a simulation model of a time-controlled switch provided in an embodiment of the present invention.

[0021] Figure 6 is a schematic diagram of a simulation model of a time-controlled switch control module provided in an embodiment of the present invention.

[0022] Figure 7 is a schematic diagram of a simulation model of an on-load tap changer control module provided in an embodiment of the present invention.

[0023] Figure 8 shows the change curves of circuit parameters displayed by the measurement and display module when the voltage is adjusted in the simulation model of the on-load tap changer of the distribution transformer provided in the embodiment of the present invention. In the figure, a is the voltage waveform of the power supply side, b is the voltage waveform of the transformer secondary side, c is the voltage waveform of the load side, and d is the power waveform of the load side.

[0024] Explanation of reference numerals in the attached diagram: 1-First protection sub-circuit; 2-Second protection sub-circuit; 3-Third protection sub-circuit; 4-Fourth protection sub-circuit; 5-Fifth protection sub-circuit; 6-Sixth protection sub-circuit; 7-Voltage source; 21-First protection circuit; 22-Second protection circuit; 23-Third protection circuit; 8-First silicon carbide N-type insulated gate bipolar transistor; 9-First RC circuit; 91-First resistor; 92-First capacitor; 10-Second RC circuit; 101-First resistor; 102-First capacitor; 11-Second silicon carbide N-type insulated gate bipolar transistor Gate bipolar transistor; 401 - First single-phase winding transformer; 402 - Second single-phase winding transformer; 403 - Third single-phase winding transformer; 404 - Fourth single-phase winding transformer; BRK1 - First switch; BRK2 - Second switch; BRK3 - Third switch; 601 - First circuit breaker; 602 - Second circuit breaker; 603 - Real constant module; 701 - Second real constant module; 702 - Pulse generation module; 703 - Enable module; 704 - Single-input comparator module; 705 - Time module; 706 - Multiplication module. Detailed Implementation

[0025] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0026] The satellite data packet parsing method provided by the present invention will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0027] Referring to Figures 1 to 8 in the specification, a flowchart illustrating a method for constructing a simulation model of an on-load tap changer for a distribution transformer according to an embodiment of the present invention is shown.

[0028] This invention provides a method for constructing a simulation model of an on-load tap changer for a distribution transformer, which may include the following steps:

[0029] S1: Construct a simulation model of a distribution transformer. The model includes an on-load tap changer, a tap regulator, a time-controlled switch, and a control module. The control module includes an on-load tap changer control module and a time-controlled switch control module.

[0030] S2: Construct the on-load tap changer, which includes a first winding transformer and a protection circuit, and connect the protection circuit to the first winding transformer;

[0031] S3: Construct the protection circuit, which includes a selection switch and a transition resistor, and connect the protection circuit to the transition resistor. The selection switch includes two silicon carbide N-type insulated gate bipolar transistors connected in anti-parallel.

[0032] S4: Construct the voltage regulator and control switch. The voltage regulator includes a second winding transformer. The control switch includes a third winding transformer, a switching assembly, and a load. The second winding transformer is coupled to the third winding transformer. One end of the switching assembly is connected to the winding of the third transformer, and the other end of the switching assembly is connected to the load.

[0033] S5: Construct the time-controlled switch control module to control the on / off state of the time-controlled switch;

[0034] S6: Construct the on-load tap changer control module to control the on / off state of the protection circuit;

[0035] S7: Construct a measurement and display module to display the circuit parameters in the simulation model of the on-load tap changer of the distribution transformer, the circuit parameters including voltage and / or current.

[0036] Specifically, the distribution transformer model is selected with a voltage level of 10kV, and the topology wiring is completed through "Wire Mode" in the software.

[0037] In this embodiment of the invention, as shown in Figure 2, the simulation model of the on-load tap changer of the distribution transformer is divided into three main modules: on-load tap changer 221, tap regulator 222, and time control switch 223. Within the on-load tap changer module, a silicon carbide-based selector switch model is incorporated. Silicon carbide possesses high voltage resistance, strong current carrying capacity, and a considerable service life, enabling arc-free switching during operation. By replacing the traditional tap changer and contacts with an on-load tap changer featuring an arc-free selector switch, and utilizing resistance, the short-circuit current generated during high-voltage winding switching is reduced, preventing the selector switch from burning out and lowering the failure rate of the mechanical on-load tap-changing distribution transformer. The two main modules of voltage regulator and time control switch are connected to the module of on-load tap changer. The control module controls the time control switch and the selection switch in the protection circuit, thereby simulating and verifying that in the actual process of using the on-load tap changer of the distribution transformer for voltage regulation, it can achieve the effects of no arcing, no oil pollution, low failure rate, high voltage regulation flexibility and fast response speed.

[0038] In one possible implementation, step S2 specifically includes:

[0039] S201: Obtain the first winding transformer, the first winding transformer including the primary and secondary windings of a first single-phase transformer, the primary and secondary windings of a second single-phase transformer and the primary and secondary windings of a third single-phase transformer, wherein the primary windings of the first single-phase transformer, the second single-phase transformer and the third single-phase transformer are connected in series, the primary winding of the first single-phase transformer has a first tap, the primary winding of the second single-phase transformer has a second tap, and the primary winding of the third single-phase transformer has a third tap.

[0040] S202: Obtain the protection circuit, which includes a first protection circuit, a second protection circuit, and a third protection circuit. Connect the first terminal of the first protection circuit to the first tap, connect the first terminal of the second protection circuit to the second tap, and connect the first terminal of the third protection circuit to the third tap to form the on-load tap changer.

[0041] Specifically, this scheme constructs a simulation model of an on-load tap changer for a distribution transformer using PSCAD / EMTDC electromagnetic transient simulation software. First, the first winding transformer is obtained from the basic model library of PSCAD / EMTDC. This first winding transformer includes the primary and secondary windings 224, 225, and 226 of a first single-phase transformer. These three single-phase transformer primary windings are connected in series to form a three-position adjustable tap changer main circuit topology. The turns ratio of the primary and secondary windings 224, 225, and 226 is 10kV / 0.4kV. The primary windings of these three single-phase transformers are connected to the protection circuit as the high-voltage side, and the secondary windings are connected to the voltage regulator and load as the low-voltage side. The protection circuit includes a first protection circuit, a second protection circuit, and a third protection circuit, each connected to one single-phase transformer.

[0042] Specifically, the capacity of a single-phase transformer, the power frequency of a single-phase transformer, the primary winding voltage of a single-phase transformer, and the secondary winding voltage of a single-phase transformer can be set to 0.015MVA, 50Hz, 10kV, and 3.4kV, respectively.

[0043] In one possible implementation, step S2 further includes:

[0044] S203: Obtain a voltage source, wherein the first end of the voltage source is connected in series with the first winding transformer, and the second end of the first protection circuit, the second end of the second protection circuit, and the second end of the third protection circuit are all connected to the second end of the voltage source.

[0045] Specifically, as shown in Figure 4, an ideal single-phase voltage source is added from the basic model library of PSCAD / EMTDC software. The first terminal of the voltage source 7 is connected in series with the first winding transformer. The second terminals of the first protection circuit, the second protection circuit, and the third protection circuit are all connected to the second terminal of the voltage source. The impedance of the ideal single-phase voltage source is zero.

[0046] In one possible implementation, step S202 specifically includes:

[0047] S2021: The first protection circuit 21 includes a first sub-protection circuit 1 and a fourth sub-protection circuit 4; the second protection circuit 22 includes a second sub-protection circuit 2 and a fifth sub-protection circuit 5; and the third protection circuit 23 includes a third sub-protection circuit 3 and a sixth sub-protection circuit 6.

[0048] Obtain the first terminal of the first sub-protection circuit 1 and the first terminal of the fourth sub-protection circuit 4, and connect the first terminal of the first sub-protection circuit 1 and the first terminal of the fourth sub-protection circuit 4 to the first tap;

[0049] Obtain the first terminal of the second sub-protection circuit 2 and the first terminal of the fifth sub-protection circuit 5, and connect the first terminal of the second sub-protection circuit 2 and the first terminal of the fifth sub-protection circuit 5 to the second tap;

[0050] Obtain the first terminal of the third sub-protection circuit 3 and the first terminal of the sixth sub-protection circuit 6, and connect both the first terminal of the third sub-protection circuit 3 and the first terminal of the sixth sub-protection circuit 6 to the third tap;

[0051] S2022: Obtain the second terminal of the first sub-protection circuit 1, the second terminal of the second sub-protection circuit 2, and the second terminal of the third sub-protection circuit 3, and connect the second terminals of the first sub-protection circuit 1, the second terminal of the second sub-protection circuit 2, and the second terminal of the third sub-protection circuit 3 to each other.

[0052] Specifically, as shown in Figure 4, a submodule is added from the basic model library of PSCAD / EMTDC software as a protection sub-circuit, thereby obtaining the first sub-protection circuit 1, the second sub-protection circuit 2, the third sub-protection circuit 3, the fourth sub-protection circuit 4, the fifth sub-protection circuit 5, and the sixth sub-protection circuit 6.

[0053] In one optional implementation, step S3 specifically includes:

[0054] S301: Obtain the selection switch, the selection switch including a first silicon carbide N-type insulated gate bipolar transistor, a first RC circuit, a second RC circuit and a second silicon carbide N-type insulated gate bipolar transistor;

[0055] S302: Obtain the collector of the first silicon carbide N-type insulated gate bipolar transistor, the first terminal of the first RC circuit, the second terminal of the second RC circuit, and the emitter of the second silicon carbide N-type insulated gate bipolar transistor; electrically connect the collector of the first silicon carbide N-type insulated gate bipolar transistor, the first terminal of the first RC circuit, the second terminal of the second RC circuit, and the emitter of the second silicon carbide N-type insulated gate bipolar transistor to each other to form the first terminal of the selection switch;

[0056] S303: Obtain the emitter of the first silicon carbide N-type insulated gate bipolar transistor, the second terminal of the first RC circuit, the first terminal of the second RC circuit, and the collector of the second silicon carbide N-type insulated gate bipolar transistor; electrically connect the emitter of the first silicon carbide N-type insulated gate bipolar transistor, the second terminal of the first RC circuit, the first terminal of the second RC circuit, and the collector of the second silicon carbide N-type insulated gate bipolar transistor to each other to form the second terminal of the selection switch;

[0057] S304: The first sub-protection circuit, the second sub-protection circuit, the third sub-protection circuit, the fourth sub-protection circuit, the fifth sub-protection circuit, and the sixth sub-protection circuit all include a selection switch. The first terminal of the selection switch of the first sub-protection circuit and the first terminal of the selection switch of the fourth sub-protection circuit are connected to the first tap. The first terminal of the selection switch of the second sub-protection circuit and the first terminal of the selection switch of the fifth sub-protection circuit are connected to the second tap. The first terminal of the selection switch of the third sub-protection circuit and the first terminal of the selection switch of the sixth sub-protection circuit are connected to the third tap.

[0058] The second terminals of the selection switches of the first sub-protection circuit, the second terminals of the selection switches of the second sub-protection circuit, and the second terminals of the selection switches of the third sub-protection circuit are electrically connected to each other.

[0059] The second terminal of the selection switch of the fourth sub-protection circuit, the second terminal of the selection switch of the fifth sub-protection circuit, and the second terminal of the selection switch of the sixth sub-protection circuit are all connected to the transition resistor.

[0060] Specifically, as shown in Figure 3, the selection switch includes a first silicon carbide N-type insulated-gate bipolar transistor (SMT) 8, a first RC circuit 9, a second RC circuit 10, and a second SMT 11. The collector of the first SMT 8, the first terminal of the first RC circuit 9, the second terminal of the second RC circuit 10, and the emitter of the second SMT 11 are electrically connected to each other to form the first terminal of the selection switch; the emitter of the first SMT 8, the second terminal of the first RC circuit 9, the first terminal of the second RC circuit 10, and the collector of the second SMT 11 are electrically connected to each other to form the second terminal of the selection switch.

[0061] Based on the advantages of silicon carbide (SiC) such as high voltage withstand capability, strong current carrying capacity, and considerable service life, a selection switch was designed to achieve arc-free switching. The SiC N-type insulated-gate bipolar transistor (SiC IGBT) also incorporates an anti-parallel diode to provide a current path when the IGBT is turned off. The first SiC N-type insulated-gate bipolar transistor 8 is connected in parallel with the first RC circuit 9, which prevents the first SiC N-type insulated-gate bipolar transistor 8 from burning out due to overvoltage during turn-off. Similarly, the second SiC N-type insulated-gate bipolar transistor 11 is connected in parallel with the second RC circuit 10, which prevents the second SiC N-type insulated-gate bipolar transistor 11 from burning out due to overvoltage during turn-off, thus preventing arcing when using this selection switch.

[0062] In one possible implementation, the first RC circuit 9 includes a first resistor 91 and a first capacitor 92. The first terminal of the first resistor 91 is the first terminal of the first RC circuit 9, and the second terminal of the first resistor 91 is connected to the first terminal of the first capacitor 92. The second terminal of the first capacitor 92 is the second terminal of the first RC circuit 9. The second RC circuit 10 includes a second resistor 101 and a second capacitor 102. The first terminal of the second resistor 101 is the first terminal of the second RC circuit 10, and the second terminal of the second resistor 101 is connected to the first terminal of the second capacitor 102. The second terminal of the second capacitor 101 is the second terminal of the second RC circuit 10. The first RC circuit 9 is used to absorb the overvoltage generated during the turn-off process of the first silicon carbide N-type insulated-gate bipolar transistor 8, and the second RC circuit 10 is used to absorb the overvoltage generated during the turn-off process of the second silicon carbide N-type insulated-gate bipolar transistor 11. That is, the combination of the first silicon carbide N-type insulated-gate bipolar transistor and the first RC circuit is connected in anti-parallel with the combination of the second silicon carbide N-type insulated-gate bipolar transistor and the second RC circuit.

[0063] In one possible implementation, the transition resistor has a resistance of 6Ω.

[0064] In one possible implementation, step S4 specifically includes:

[0065] S401: Obtain the second winding transformer, which is the first single-phase winding transformer 401. The first single-phase winding transformer 401 is connected in series with the secondary winding of the first single-phase transformer, the secondary winding of the second single-phase transformer, and the secondary winding of the third single-phase transformer.

[0066] S402: Obtain the third winding transformer, which includes a second single-phase winding transformer 402, a third single-phase winding transformer 403, and a fourth single-phase winding transformer 404. The second single-phase winding transformer 402, the third single-phase winding transformer 403, and the fourth single-phase winding transformer 404 are connected in series. The second single-phase winding transformer 402 has a fourth tap, the third single-phase winding transformer 403 has a fifth tap, and the fourth single-phase winding transformer 404 has a sixth tap, to form the voltage regulator.

[0067] S403: Obtain the switch assembly, which includes a first switch BRK1, a second switch BRK2, and a third switch BRK3. The first end of the first switch BRK1 is connected to the fourth tap, the first end of the second switch BRK2 is connected to the fifth tap, and the first end of the third switch BRK3 is connected to the sixth tap. The second ends of the first switch BRK1, the second switch BRK2, and the third switch BRK3 are all connected to the first end of the load 405. The second end of the load 405 is connected in series with the third winding transformer to form the control switch.

[0068] Specifically, as shown in Figure 5, a single-phase four-winding transformer, three control switches, and a resistive load are selected from the basic model library of PSCAD / EMTDC software and connected together to form an automatic voltage regulator module with adjustable load voltage, used to simulate load voltage fluctuations. The three control switches are BRK1, BRK2, and BRK3. By adjusting the on / off state of the control switches, the voltage across the low-voltage side load is adjusted.

[0069] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0070] In this embodiment of the invention, by adjusting the time-controlled switch and the transformer containing the arc-free three-phase on-load tap changer, the distribution transformer can achieve multi-level adjustment, which improves the switching flexibility of the distribution transformer and reduces the problems of large arc and long switching time.

[0071] Optionally, the resistive load is 1Ω.

[0072] In one possible implementation, step S5 specifically includes:

[0073] S501: The module for obtaining the first real constant, the circuit breaker timing control logic module, and the first data tag module;

[0074] S502: Connect the first real constant module to the second switch. The circuit breaker timing control logic module includes a first circuit breaker timing control logic module and a second circuit breaker timing control logic module. The first circuit breaker timing control logic module is connected to the first switch, and the second circuit breaker timing control logic module is connected to the third switch. The first data tag module includes a first sub-data tag module, a second sub-data tag module, and a third sub-data tag module. The first sub-tag module is located at the first switch, the second sub-tag module is located at the second switch, and the third sub-tag module is located at the third switch. The first circuit breaker timing control logic module, the second circuit breaker timing control logic module, and the first real constant module control the first switch, the second switch, and the third switch.

[0075] Specifically, as shown in Figure 6, the first circuit breaker 601 is connected to the first switch BRK1, the second circuit breaker 602 is connected to the third switch BRK3, and the second switch BRK2 is connected to the real constant module 603, so that the first switch BRK1 and the third switch BRK3 can achieve the function of opening or closing according to the timing control, thereby achieving the voltage regulation of the load.

[0076] In one possible implementation, step S6 specifically includes:

[0077] S601: Second real constant acquisition module 701, second data tag module, pulse generation module 702, enable module 703, multiplication module 706, single-input comparator module 704, time module 705;

[0078] S602: The second real constant module 701 is connected to the pulse generation module 702. The pulse generation module 702 is connected to the first end of the enable module 703. The second end of the enable module 703 and the second end of the single-input comparator module 704 are both connected to the first end of the multiplication module 706. The time module 705 is connected to the first end of the single-input comparator module 704. The second end of the multiplication module 706 is connected to the protection circuit to control the on / off state of the protection circuit.

[0079] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0080] In this embodiment of the invention, six trigger pulse control signals G11, G12, G51, G52, G21, and G22 act sequentially to adjust the high-voltage side winding from the second to the first position. Specifically, the high-voltage side winding is adjusted from high to low as the first, second, and third positions, achieving the goal of increasing the voltage on the low-voltage side of the transformer.

[0081] In one possible implementation, step S7 specifically includes:

[0082] S701: Obtain the third data tag and the display output channel;

[0083] S702: The display output channel includes a first display output channel and a second display output channel. The first display output channel is connected in series between the first terminal of the voltage source and the first winding transformer, and the second display output channel is connected in series between the second terminal of the load and the third winding transformer. It is used to display at least one of the circuit parameters: the voltage of the voltage source, the current of the load, and the voltage of the load.

[0084] Specifically, the display output channel includes a multi-meter measurement module and a voltage and current signal measurement module. The multi-meter measurement module is configured to display active and reactive power; the voltage and current signal measurement module is used to measure circuit parameters, such as current or voltage values. When connecting the display output channel in the simulation model, taking the first display output channel located between the voltage source and the first winding transformer as an example, the connection sequence is as follows: the left voltage source is first connected to the multi-meter measurement module, then to the voltage and current signal measurement module, then to the selection switch in the protection circuit, then to the first winding transformer, then to the second winding transformer, then to the third winding transformer, and finally to the time control switch and the load.

[0085] As shown in Figure 8, after constructing the simulation model using the above-described method for constructing an on-load tap changer simulation model of a distribution transformer, a voltage regulation condition of the load can be established to test the effectiveness of the constructed model and the feasibility of the switching control strategy. The tap changer inter-stage switching control module is instructed to perform an upward voltage adjustment operation at 0.3s with an upward adjustment magnitude of 2%. Its dynamic response process is observed, and the response curves of variables such as voltage and current during the dynamic response process are shown in Figure 8. The power supply side voltage waveform can be displayed through the display module, as shown in Figure a. The power supply side voltage exhibits a sinusoidal waveform and is relatively stable, with an effective value of 10kV. The transformer secondary side voltage waveform is shown in Figure b. The secondary side voltage has stabilized before 0.3s, exhibiting a sinusoidal waveform with an effective value of 0.3kV. After a 0.06s transition period following the upward voltage adjustment operation at 0.3s, the secondary side voltage stabilizes again with an effective value of 0.32kV, representing a voltage adjustment magnitude of 2%. The load-side voltage waveform is shown in Figure c. Before 0.3 seconds, the load-side voltage tends to stabilize. Line losses cause the effective value of the load-side voltage to decrease, with a steady-state value of 0.3 kV. After a transition period of 0.06 seconds following 0.3 seconds, the effective value of the load-side voltage is 0.29 kV, with a voltage regulation amplitude of 1.9%. The load-side power diagram is shown in Figure d. The active power corresponding to the load-side power has a steady-state value of 4.6 kW within 0-0.3 seconds. Due to voltage regulation, there is a response fluctuation within 0.3 seconds, and the steady-state value is 4.8 kW within 0.3-1.5 seconds. The corresponding reactive power stabilizes at 0 within 0-1.5 seconds.

[0086] Therefore, it can be seen that the on-load tap changer topology is effective, proving that the model can avoid arcing and oil contamination during voltage regulation, has a low failure rate, high voltage regulation flexibility, and fast response speed.

[0087] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. A method for constructing a simulation model of an on-load tap changer for a distribution transformer, characterized in that, include: S1: Construct a simulation model of the distribution transformer, which includes an on-load tap changer, a voltage regulator, a time-controlled switch, and a control module. The control module includes an on-load tap changer control module and a time-controlled switch control module. S2: Construct the on-load tap changer, which includes a first winding transformer and a protection circuit. Connect the protection circuit to the first winding transformer. S3: Construct the protection circuit, which includes a selection switch and a transition resistor. Connect the protection circuit to the transition resistor. The selection switch includes two anti-parallel silicon carbide N-type insulated-gate bipolar transistors. S4: Construct the voltage regulator... The transformer and the time-controlled switch are configured such that the voltage regulator includes a second winding transformer, the time-controlled switch includes a third winding transformer, a switching assembly, and a load. The second winding transformer is coupled to the third winding transformer, one end of the switching assembly is connected to the winding of the third transformer, and the other end of the switching assembly is connected to the load. S5: Construct the time-controlled switch control module to control the on / off state of the time-controlled switch. S6: Construct the on-load tap changer control module to control the on / off state of the protection circuit. S7: Construct a measurement and display module to display the circuit parameters in the simulation model of the distribution transformer, the circuit parameters including voltage and / or current.

2. The method for constructing a simulation model of an on-load tap changer for a distribution transformer according to claim 1, characterized in that, S2 specifically includes: S201: Obtaining the first winding transformer, the first winding transformer including the primary and secondary windings of a first single-phase transformer, the primary and secondary windings of a second single-phase transformer, and the primary and secondary windings of a third single-phase transformer, wherein the primary windings of the first single-phase transformer, the second single-phase transformer, and the third single-phase transformer are connected in series, the primary winding of the first single-phase transformer has a first tap, the primary winding of the second single-phase transformer has a second tap, and the primary winding of the third single-phase transformer has a third tap; S202: Obtaining the protection circuit, the protection circuit including a first protection circuit, a second protection circuit, and a third protection circuit, connecting the first terminal of the first protection circuit to the first tap, connecting the first terminal of the second protection circuit to the second tap, and connecting the first terminal of the third protection circuit to the third tap, to form the on-load tap changer.

3. The method for constructing a simulation model of an on-load tap changer for a distribution transformer according to claim 2, characterized in that, S2 further includes: S203: obtaining a voltage source, wherein the first end of the voltage source is connected in series with the first winding transformer, and the second end of the first protection circuit, the second end of the second protection circuit, and the second end of the third protection circuit are all connected to the second end of the voltage source.

4. The method for constructing a simulation model of an on-load tap changer for a distribution transformer according to claim 3, characterized in that, S202 specifically includes: S2021: The first protection circuit includes a first sub-protection circuit and a fourth sub-protection circuit; the second protection circuit includes a second sub-protection circuit and a fifth sub-protection circuit; the third protection circuit includes a third sub-protection circuit and a sixth sub-protection circuit; obtaining the first terminal of the first sub-protection circuit and the first terminal of the fourth sub-protection circuit, and connecting both the first terminal of the first sub-protection circuit and the first terminal of the fourth sub-protection circuit to the first tap; obtaining the first terminal of the second sub-protection circuit and the first terminal of the fifth sub-protection circuit, and connecting both the first terminal of the second sub-protection circuit and the first terminal of the fifth sub-protection circuit to the second tap; obtaining the first terminal of the third sub-protection circuit and the first terminal of the sixth sub-protection circuit, and connecting both the first terminal of the third sub-protection circuit and the first terminal of the sixth sub-protection circuit to the third tap; S2022: obtaining the second terminals of the first sub-protection circuit, the second sub-protection circuit, and the third sub-protection circuit, and connecting the second terminals of the first sub-protection circuit, the second sub-protection circuit, and the third sub-protection circuit to each other.

5. The method for constructing a simulation model of an on-load tap changer for a distribution transformer according to claim 4, characterized in that, S3 specifically includes: S301: Obtaining the selection switch, the selection switch including a first silicon carbide N-type insulated gate bipolar transistor, a first RC circuit, a second RC circuit, and a second silicon carbide N-type insulated gate bipolar transistor; S302: Obtaining the collector of the first silicon carbide N-type insulated gate bipolar transistor, the first terminal of the first RC circuit, the second terminal of the second RC circuit, and the emitter of the second silicon carbide N-type insulated gate bipolar transistor, and electrically connecting the collector of the first silicon carbide N-type insulated gate bipolar transistor, the first terminal of the first RC circuit, the second terminal of the second RC circuit, and the emitter of the second silicon carbide N-type insulated gate bipolar transistor to form the first terminal of the selection switch; S303: Obtaining the emitter of the first silicon carbide N-type insulated gate bipolar transistor, the second terminal of the first RC circuit, the first terminal of the second RC circuit, and the collector of the second silicon carbide N-type insulated gate bipolar transistor, and electrically connecting the emitter of the first silicon carbide N-type insulated gate bipolar transistor, the second terminal of the first RC circuit, the first terminal of the second RC circuit, and the emitter of the second silicon carbide N-type insulated gate bipolar transistor to form the first terminal of the selection switch; The collectors of the second silicon carbide N-type insulated gate bipolar transistor are electrically connected to each other to form the second terminal of the selection switch; S304: The first sub-protection circuit, the second sub-protection circuit, the third sub-protection circuit, the fourth sub-protection circuit, the fifth sub-protection circuit, and the sixth sub-protection circuit all include a selection switch. The first terminals of the selection switches of the first and fourth sub-protection circuits are connected to the first tap. The first terminals of the selection switches of the second and fifth sub-protection circuits are connected to the second tap. The first terminals of the selection switches of the third and sixth sub-protection circuits are connected to the third tap. The second terminals of the selection switches of the first, second, and third sub-protection circuits are electrically connected to each other. The second terminals of the selection switches of the fourth, fifth, and sixth sub-protection circuits are all connected to the transition resistor.

6. The method for constructing a simulation model of an on-load tap changer for a distribution transformer according to claim 5, characterized in that, The resistance of the transition resistor is 6Ω.

7. The method for constructing a simulation model of an on-load tap changer for a distribution transformer according to claim 6, characterized in that, S4 specifically includes: S401: Obtaining a second winding transformer, the second winding transformer being a first single-phase winding transformer, the first single-phase winding transformer being connected in series with the secondary windings of the first single-phase transformer, the second single-phase transformer, and the third single-phase transformer; S402: Obtaining the third winding transformer, the third winding transformer including a second single-phase winding transformer, a third single-phase winding transformer, and a fourth single-phase winding transformer, the second single-phase winding transformer, the third single-phase winding transformer, and the fourth single-phase winding transformer being connected in series, and the second single-phase winding transformer having a fourth tap. The third single-phase winding transformer has a fifth tap, and the fourth single-phase winding transformer has a sixth tap to form the voltage regulator; S403: Obtain the switching assembly, which includes a first switch, a second switch, and a third switch. The first end of the first switch is connected to the fourth tap, the first end of the second switch is connected to the fifth tap, and the first end of the third switch is connected to the sixth tap. The second ends of the first switch, the second switch, and the third switch are all connected to the first end of the load. The second end of the load is connected in series with the third winding transformer to form the control switch.

8. The method for constructing a simulation model of an on-load tap changer for a distribution transformer according to claim 7, characterized in that, S5 specifically includes: S501: acquiring a first real constant module, a circuit breaker timing control logic module, and a first data tag module; S502: connecting the first real constant module to the second switch, the circuit breaker timing control logic module including a first circuit breaker timing control logic module and a second circuit breaker timing control logic module, the first circuit breaker timing control logic module being connected to the first switch, the second circuit breaker timing control logic module being connected to the third switch, the first data tag module including a first sub-data tag module, a second sub-data tag module, and a third sub-data tag module, the first sub-tag module being located at the first switch, the second sub-tag module being located at the second switch, and the third sub-tag module being located at the third switch, controlling the first switch, the second switch, and the third switch through the first circuit breaker timing control logic module, the second circuit breaker timing control logic module, and the first real constant module.

9. The method for constructing a simulation model of an on-load tap changer for a distribution transformer according to claim 2, characterized in that, S6 specifically includes: S601: acquiring a second real constant module, a second data tag module, a pulse generation module, an enable module, a multiplication module, a single-input comparator module, and a time module; S602: the second real constant module is connected to the pulse generation module, the pulse generation module is connected to the first terminal of the enable module, the second terminal of the enable module and the second terminal of the single-input comparator module are both connected to the first terminal of the multiplication module, the time module is connected to the first terminal of the single-input comparator module, and the second terminal of the multiplication module is connected to the protection circuit to control the on / off state of the protection circuit.

10. The method for constructing a simulation model of an on-load tap changer for a distribution transformer according to claim 7, characterized in that, S7 specifically includes: S701: acquiring the third data tag and the display output channel; S702: the display output channel includes a first display output channel and a second display output channel, the first display output channel is connected in series between the first terminal of the voltage source and the first winding transformer, and the second display output channel is connected in series between the second terminal of the load and the third winding transformer, for displaying at least one of the circuit parameters: the voltage of the voltage source, the current of the load, and the voltage of the load.

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