CN110661241A - Method, device and equipment for suppressing inrush current of transformer - Google Patents
Method, device and equipment for suppressing inrush current of transformer Download PDFInfo
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- CN110661241A CN110661241A CN201910984466.2A CN201910984466A CN110661241A CN 110661241 A CN110661241 A CN 110661241A CN 201910984466 A CN201910984466 A CN 201910984466A CN 110661241 A CN110661241 A CN 110661241A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/001—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection limiting speed of change of electric quantities, e.g. soft switching on or off
- H02H9/002—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection limiting speed of change of electric quantities, e.g. soft switching on or off limiting inrush current on switching on of inductive loads subjected to remanence, e.g. transformers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/42—Circuits specially adapted for the purpose of modifying, or compensating for, electric characteristics of transformers, reactors, or choke coils
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/04—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for transformers
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Abstract
The application discloses a transformer inrush current suppression method, a transformer inrush current suppression device and a transformer inrush current suppression device, based on three-phase split-phase pre-magnetization and split-phase-controlled switching-on of a transformer, magnetic fluxes of windings of all phases are charged to saturation magnetic fluxes one by one and then switched on one by one, so that each phase inrush current is effectively suppressed, excitation inrush current is hardly generated in the whole process, the size of residual magnetism of an iron core is not required to be known, and the technical problems that the existing transformer inrush current suppression method needs to depend on the residual magnetism of the known transformer, and each phase excitation inrush current cannot be effectively suppressed under the condition that the residual magnetism of the transformer is unknown are solved.
Description
Technical Field
The application relates to the technical field of transformers, in particular to a transformer inrush current suppression method, device and equipment.
Background
The transformer often can produce excitation inrush current in the closing process, and the multiple of inrush current can be as high as 10 times of rated current, and these heavy currents will heat the winding significantly, lead to insulation degradation, and the mechanical force of excitation inrush current and rated cutout force are at the same level, and great excitation inrush current probably causes the mechanical damage of transformer.
The high-impedance transformer is more and more widely applied to a power grid due to the excellent capacity of limiting short-circuit current, however, when the high-impedance transformer is applied on site, inrush current generated by the high-impedance transformer in the switching-on process for many times also occurs, so that the accident of misoperation of zero-sequence overcurrent protection of a superior line is caused, and the safe and stable operation of the power grid is seriously endangered, therefore, the research on the method for inhibiting the switching-on inrush current of the transformer has important significance for the safe and stable operation of the transformer and the power grid. In the existing inrush current suppression measures, a phase control method is adopted to suppress inrush current, and when the residual magnetism of a transformer is known, an appropriate closing angle is selected to effectively suppress inrush current, however, the residual magnetism of an iron core of the transformer is difficult to obtain, for example, after a direct current resistance test of the transformer, the residual magnetism of the iron core is difficult to estimate, and the technical effect of phase control is poor.
Disclosure of Invention
The application provides a transformer inrush current suppression method, a transformer inrush current suppression device and transformer inrush current suppression equipment, which are used for solving the technical problems that an existing transformer inrush current suppression method needs to depend on the residual magnetism of a known transformer, and the magnetizing inrush current of each phase cannot be effectively suppressed under the condition of the residual magnetism of the unknown transformer.
In view of the above, a first aspect of the present application provides a method for suppressing inrush current of a transformer, including the following steps:
injecting a first preset direct current into a phase A of a transformer to enable the magnetic flux of the phase A of the transformer to be saturated;
turning off the first preset direct current, and switching on a winding of the phase A of the transformer at an optimal switching-on phase of the phase A voltage, wherein the optimal switching-on phase is a phase in which a transient magnetic flux generated by switching-on and a saturated magnetic flux after the phase A is magnetized are offset;
injecting a second preset direct current into the phase B of the transformer to enable the magnetic flux of the phase B of the transformer to be saturated;
turning off the second preset direct current, and switching on a winding of the B phase of the transformer at the optimal switching-on phase of the B phase voltage;
and switching on the winding of the C phase of the transformer at a preset time.
Optionally, the injecting a first preset direct current into the transformer a phase to saturate the magnetic flux of the transformer a phase includes:
injecting a first preset direct current into the A phase of the transformer based on a capacitor discharging mode, so that the magnetic flux of the A phase of the transformer reaches saturation.
Optionally, the charging capacitance of the capacitor is:
wherein L ismFor exciting the inductance, fNAt power frequency, VcapCharging the capacitor with voltage, VNThe rated voltage of the transformer.
Optionally, the first preset direct current and the second preset direct current are both 2 times of rated excitation current of the transformer core.
Optionally, the optimal closing phase is 180 °.
Optionally, the injecting a second preset direct current into the transformer B phase to saturate the magnetic flux of the transformer B phase includes:
and injecting a second preset direct current into the phase B of the transformer 0.02s after the phase A of the transformer is switched on, so that the magnetic flux of the phase B of the transformer reaches saturation.
Optionally, the preset time is a period after the phase B of the transformer is switched on.
The second aspect of the present application provides a transformer inrush current suppression device, including the following modules:
the A-phase current charging module is used for injecting a first preset direct current into the A phase of the transformer to enable the magnetic flux of the A phase of the transformer to be saturated;
the A-phase current turn-off module is used for turning off the first preset direct current and switching on a winding of the A phase of the transformer at an optimal switching-on phase of the A-phase voltage, wherein the optimal switching-on phase is a phase in which a transient magnetic flux generated by switching-on and a saturated magnetic flux after the A phase is magnetized are offset;
the B-phase current charging module is used for injecting a second preset direct current into the B phase of the transformer so as to enable the magnetic flux of the B phase of the transformer to be saturated;
the B-phase current turn-off module is used for turning off the second preset direct current and switching on a winding of the B phase of the transformer at the optimal switching-on phase of the B-phase voltage;
and the C-phase switching-on module is used for switching on the winding of the C phase of the transformer at a preset time.
Optionally, the a-phase current charging module is specifically configured to:
injecting a first preset direct current into the phase A of the transformer based on a capacitor discharging mode to enable the magnetic flux of the phase A of the transformer to be saturated;
the B-phase current charging module is specifically configured to:
and injecting a second preset direct current into the phase B of the transformer 0.02s after the phase A of the transformer is switched on, so that the magnetic flux of the phase B of the transformer reaches saturation.
A third aspect of the present application provides a transformer inrush current suppression device, the device comprising a processor and a memory:
the memory is used for storing program codes and transmitting the program codes to the processor;
the processor is configured to execute the transformer inrush current suppression method according to instructions in the program code.
According to the technical scheme, the embodiment of the application has the following advantages:
the application provides a method for suppressing inrush current of a transformer, which comprises the following steps: injecting a first preset direct current into the phase A of the transformer to enable the magnetic flux of the phase A of the transformer to be saturated; turning off the first preset direct current, and switching on a winding of the A phase of the transformer at an optimal switching-on phase of the A phase voltage, wherein the optimal switching-on phase is a phase in which transient magnetic flux generated by switching-on and saturated magnetic flux after the A phase is magnetized are offset; injecting a second preset direct current into the phase B of the transformer to enable the magnetic flux of the phase B of the transformer to be saturated; turning off the second preset direct current, and switching on the winding of the B phase of the transformer at the optimal switching-on phase position of the B phase voltage; and switching on the winding of the C phase of the transformer at a preset time. The transformer inrush current suppression method provided by the application is based on three-phase split-phase pre-magnetizing and split-phase-controlled switching-on of a transformer, and switching-on is performed one by one after magnetic fluxes of windings of each phase are charged to saturation magnetic fluxes one by one, so that each phase inrush current is effectively suppressed, excitation inrush current is hardly generated in the whole process, the size of residual magnetism of an iron core is not required to be known, and the technical problems that the existing transformer inrush current suppression method needs to depend on the known transformer residual magnetism, and each phase excitation inrush current cannot be effectively suppressed under the condition that the residual magnetism of the transformer is unknown are solved.
Drawings
Fig. 1 is a schematic flow chart illustrating an embodiment of a method for suppressing inrush current of a transformer according to the present application;
FIG. 2 is a schematic diagram of a pre-magnetizing and split-phase closing circuit;
FIG. 3 is a schematic flow chart illustrating another embodiment of a transformer inrush current suppression method provided herein;
FIG. 4 is a schematic diagram of pre-magnetizing DC current calculation;
FIG. 5 is a schematic diagram showing the variation of three-phase magnetic flux density during pre-magnetizing split-phase closing;
FIG. 6 is a schematic diagram showing the variation of three-phase voltages during pre-magnetizing split-phase closing;
FIG. 7 is a schematic diagram of the inrush current suppression effect of the pre-magnetizing split-phase closing;
FIG. 8 is a schematic diagram of the inrush current suppression effect of non-pre-magnetizing split-phase closing;
FIG. 9 is a schematic diagram of the inrush current suppression effect of the pre-magnetizing three-phase switching-on;
fig. 10 is a schematic structural diagram of an embodiment of a transformer inrush current suppression device provided in the present application.
Detailed Description
In order to make the technical solutions of the present application better understood, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
For ease of understanding, referring to fig. 1, the present application provides an embodiment of a method for suppressing inrush current in a transformer, including:
step 101, injecting a first preset direct current into the phase a of the transformer to make the magnetic flux of the phase a of the transformer reach saturation.
Please refer to fig. 2, fig. 2 is a schematic diagram of a pre-charging and split-phase switching-on circuit, in which an a-phase charging power supply is switched on and is charged with a first preset dc current IaThe magnetic flux of the a phase of the transformer is saturated.
And 102, turning off the first preset direct current, and switching on the winding of the A phase of the transformer at the optimal switching-on phase of the A phase voltage.
The optimum closing phase is a phase in which a transient magnetic flux generated by closing and a saturated magnetic flux after the a-phase magnetization cancel each other, and is set at the optimum closing phase (denoted as t)1Time of day) switching on will generate transient magnetic fluxThe saturated magnetic flux after the A phase is magnetized is completely offset, and the A phase switching-on can not generate inrush current.
And 103, injecting a second preset direct current into the phase B of the transformer to enable the magnetic flux of the phase B of the transformer to be saturated.
Please refer to fig. 2, fig. 2 is a schematic diagram of a pre-charging and split-phase switching-on circuit, a B-phase charging power source is switched on, and a second preset dc current I is chargedbThe magnetic flux of the B phase of the transformer is saturated. Second preset DC current IbCan be matched with the first preset direct current IaThe current levels of (a) and (b) are the same. After phase A is closed, phiAThe phase A voltage is determined to be a standard sine, and the phase A core column is equivalent to a current source corresponding to the magnetic circuit. According to the related flux linkage analysis, after the B-phase magnetization is finished, when the A-phase magnetic flux is near the minimum value, the B-phase magnetic flux enters a saturation state with almost unchanged magnitude.
And step 104, turning off the second preset direct current, and switching on the winding of the B phase of the transformer at the optimal switching-on phase position of the B phase voltage.
Note that, when the B-phase magnetic flux is in a saturation period, the phase is switched on when the B-phase voltage phase is at the optimal switching-on phase (denoted as t)2At time), phase B will not produce a surge.
And 105, switching on the winding of the C phase of the transformer at a preset time.
After the switch-on of the two phases AB is completed, according to the symmetry relationship of the magnetic fluxes, the induced C-phase magnetic flux has no dc component, so that no inrush current is generated in any phase of the C-phase voltage, and the C-phase can be switched on in a cycle after the switch-on of the phase B.
The transformer inrush current suppression method provided by the embodiment of the application is based on three-phase split-phase pre-magnetizing and split-phase-controlled switching-on of a transformer, and after magnetic fluxes of windings of all phases are charged to saturated magnetic fluxes one by one, the switching-on is performed one by one, so that the inrush current of all phases is effectively suppressed, the magnetizing inrush current is hardly generated in the whole process, the size of the residual magnetism of an iron core is not required to be known, and the technical problems that the existing transformer inrush current suppression method depends on the residual magnetism of the known transformer and the magnetizing inrush current of all phases cannot be effectively suppressed under the condition that the residual magnetism of the transformer is unknown are solved.
For ease of understanding, referring to fig. 3, another embodiment of a method for suppressing inrush current in a transformer is provided, comprising:
It should be noted that, in practical engineering applications, if a current source is connected from the high-voltage side of a transformer, a high insulation requirement is required to be met. Therefore, in the embodiment of the present application, the capacitor discharge mode is used to replace the charging of the dc current source, and the first preset dc current I is injected into the a phase of the transformeraThe magnetic flux of the a phase of the transformer is saturated. Assume that the capacitor charging voltage is VcapThe charging capacitance is CpfThe magnetic flux saturation value of the iron core is phiNExcitation inductance of LmInitial remanence of the core is phirThen is-phiN≤φr≤φN. Then the capacitor C is chargedpfWill satisfy:
wherein VNRated voltage of transformer, fNIs the power frequency.
To ensure that the transformer charges to saturation at all remanence moments, the capacitance can be maximized, i.e. it is
In practical engineering applications, the capacitance CpfAnd selecting the size of the specification closest to the calculation result.
As shown in FIG. 4, the pre-magnetizing DC calculation schematic diagram needs to be charged to a transformer core with a current value to ensure that the magnetic flux of the A-phase core can reach a saturation value after being charged under any initial remanence condition2 times rated exciting current, i.e. first preset DC current Ia＝2Im。
In the embodiment of the present application, when the optimal a-phase closing phase voltage is selected to be 180 ° (denoted as t)1Time) of the switch-on, the transient magnetic flux generated by the switch-on will be completely offset with the saturated magnetic flux after the A phase is magnetized, and the A phase switch-on will not generate inrush current.
And 203, injecting a second preset direct current into the B phase of the transformer 0.02s after the A phase of the transformer is switched on, so that the magnetic flux of the B phase of the transformer is saturated.
It should be noted that, in the embodiment of the present application, the B-phase winding is magnetized 0.02s after the a-phase is switched on, and the magnitude of the magnetizing current is the same as that of the a-phase, that is, the second preset direct current IbFirst preset direct current Ia. After phase A is closed, phiAThe phase A voltage is determined to be a standard sine, and the phase A core column is equivalent to a current source corresponding to the magnetic circuit. According to the related flux linkage analysis, after the B-phase magnetization is finished, when the A-phase magnetic flux is near the minimum value, the B-phase magnetic flux enters a saturation state with almost unchanged magnitude.
And step 204, turning off the second preset direct current, and switching on the winding of the B phase of the transformer at the optimal switching-on phase position of the B phase voltage.
Note that, when the B-phase magnetic flux is in a saturation period, the phase is switched on when the B-phase voltage phase is at the optimal switching-on phase (denoted as t)2At time), phase B will not produce a surge.
And 205, switching on the winding of the transformer C phase in one period after the transformer B phase is switched on.
It should be noted that, after the AB two-phase switching-on is completed, according to the symmetric relationship of the magnetic fluxes, the induced C-phase magnetic flux has no dc component, thenThe switching-on of the C phase voltage at any phase does not generate inrush current, and the C phase can be switched on in one period after the switching-on of the B phase, namely t3＝t2+0.02。
In order to better explain the inrush current suppression method of the transformer provided in the embodiment of the present application, a specific application example is provided below, and a two-winding three-phase transformer is selected to verify the effectiveness of the inrush current suppression method of the transformer provided in the embodiment of the present application.
The basic parameters of the tested transformer are shown in Table 1, and the capacitor charging voltage V is selectedcap100V, according to formula
Can obtain Cpf178 uF. Selecting C from standard specification of capacitorpf＝180uF。
TABLE 1 basic parameters of the tested transformers
| Capacity of | 20kVA |
| Voltage class | 800V/38.2V |
| Rated current | 14.43A/302.3A |
| Short circuit loss | 409W |
| No load loss | 118W |
When the initial remanence of the transformer is selected to be 0, comparing the inrush current suppression method provided in the embodiment of the application, namely the pre-magnetizing split-phase closing phase control strategy with the inrush current suppression effect under the non-pre-magnetizing split-phase closing strategy and the pre-magnetizing three-phase closing strategy. The pre-magnetizing split-phase closing process is shown in fig. 5 to 6, and the comparison result of the inrush current simulation is shown in fig. 7 to 9.
Under different typical remanence conditions, the maximum value of inrush current of each phase with or without pre-magnetization and the maximum effective value of zero-mode inrush current are shown in table 2. Therefore, after the pre-magnetizing split-phase inrush current suppression strategy is adopted, the inrush current of each phase is greatly reduced, and the effectiveness of inrush current suppression of the transformer inrush current suppression method is verified.
TABLE 2
The transformer inrush current suppression method provided by the embodiment of the application is based on three-phase split-phase pre-magnetizing and split-phase-controlled switching-on of a transformer, and after magnetic fluxes of windings of all phases are charged to saturated magnetic fluxes one by one, the switching-on is performed one by one, so that the inrush current of all phases is effectively suppressed, the magnetizing inrush current is hardly generated in the whole process, the size of the residual magnetism of an iron core is not required to be known, and the technical problems that the existing transformer inrush current suppression method depends on the residual magnetism of the known transformer and the magnetizing inrush current of all phases cannot be effectively suppressed under the condition that the residual magnetism of the transformer is unknown are solved. Meanwhile, the problem that charging current is difficult to determine due to magnetic flux coupling of all phases when the pre-magnetizing three phases of the transformer are simultaneously switched on is also solved. Pre-magnetizing three-phase simultaneous closing energy corresponding to YNYNThe inrush current suppression problem of the connected three-phase transformer under the condition that the remanence is 0, and when the remanence is unknown, the three-phase magnetic flux after magnetization needs to meet the 120-degree symmetric relation, so that the magnitude of the pre-magnetization current is difficult to determine.
For ease of understanding, referring to fig. 10, an embodiment of a transformer inrush current suppression device is provided herein, comprising the following modules:
the a-phase current charging module 301 is configured to inject a first preset dc current into the a-phase of the transformer, so that the magnetic flux of the a-phase of the transformer is saturated.
The a-phase current turn-off module 302 is configured to turn off the first preset direct current, and turn on the winding of the a-phase of the transformer at an optimal a-phase voltage closing phase, where the optimal closing phase is a phase where a transient magnetic flux generated by closing and a saturated magnetic flux after the a-phase is magnetized are cancelled.
And the B-phase current charging module 303 is configured to inject a second preset direct current into the B-phase of the transformer, so that the magnetic flux of the B-phase of the transformer is saturated.
And the phase-B current turn-off module 304 is configured to turn off the second preset dc current, and turn on the winding of the phase B of the transformer at the optimal switching-on phase of the phase-B voltage.
And the C-phase switching module 305 is configured to switch on the winding of the C-phase of the transformer at a preset time.
As a further improvement, the a-phase current charging module 301 is specifically configured to:
injecting a first preset direct current into the phase A of the transformer based on a capacitor discharging mode to enable the magnetic flux of the phase A of the transformer to be saturated;
the charging capacitance of the capacitor is:
wherein L ismFor exciting the inductance, fNAt power frequency, VcapCharging the capacitor with voltage, VNThe rated voltage of the transformer.
The B-phase current charging module 303 is specifically configured to:
and injecting a second preset direct current into the B phase of the transformer 0.02s after the A phase of the transformer is switched on, so that the magnetic flux of the B phase of the transformer reaches saturation.
The first preset direct current and the second preset direct current are both 2 times of rated exciting current of the transformer iron core.
The optimal closing phase of the A phase and the B phase is 180 degrees.
The C-phase switching module 305 is specifically configured to switch on the winding of the C-phase of the transformer in one cycle after the B-phase of the transformer is switched on.
The application also provides a transformer inrush current suppression device, which comprises a processor and a memory:
the memory is used for storing program codes and transmitting the program codes to the processor;
the processor is configured to execute any one of the transformer inrush current suppression method embodiments described above according to instructions in the program code.
In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be substantially implemented or contributed to by the prior art, or all or part of the technical solution may be embodied in a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.
Claims (10)
1. A method for suppressing inrush current of a transformer is characterized by comprising the following steps:
injecting a first preset direct current into a phase A of a transformer to enable the magnetic flux of the phase A of the transformer to be saturated;
turning off the first preset direct current, and switching on a winding of the phase A of the transformer at an optimal switching-on phase of the phase A voltage, wherein the optimal switching-on phase is a phase in which a transient magnetic flux generated by switching-on and a saturated magnetic flux after the phase A is magnetized are offset;
injecting a second preset direct current into the phase B of the transformer to enable the magnetic flux of the phase B of the transformer to be saturated;
turning off the second preset direct current, and switching on a winding of the B phase of the transformer at the optimal switching-on phase of the B phase voltage;
and switching on the winding of the C phase of the transformer at a preset time.
2. The method for suppressing the inrush current of a transformer according to claim 1, wherein the injecting a first preset direct current into the a-phase of the transformer to saturate the magnetic flux of the a-phase of the transformer comprises:
injecting a first preset direct current into the A phase of the transformer based on a capacitor discharging mode, so that the magnetic flux of the A phase of the transformer reaches saturation.
3. The transformer inrush current suppression method of claim 2, wherein a charging capacitance of the capacitor is:
wherein L ismFor exciting the inductance, fNAt power frequency, VcapCharging the capacitor with voltage, VNThe rated voltage of the transformer.
4. The transformer inrush current suppression method of claim 1, wherein the first preset direct current and the second preset direct current are both 2 times rated excitation current of a transformer core.
5. The transformer inrush current suppression method of claim 1, wherein the optimal closing phase is 180 °.
6. The method for suppressing the inrush current of a transformer according to claim 1, wherein the step of injecting a second preset direct current into the B-phase of the transformer so that the magnetic flux of the B-phase of the transformer is saturated comprises the steps of:
and injecting a second preset direct current into the phase B of the transformer 0.02s after the phase A of the transformer is switched on, so that the magnetic flux of the phase B of the transformer reaches saturation.
7. The transformer inrush current suppression method of claim 1, wherein the preset time is a period after a switch-on of the transformer B-phase.
8. A transformer inrush current suppression device, comprising the following modules:
the A-phase current charging module is used for injecting a first preset direct current into the A phase of the transformer to enable the magnetic flux of the A phase of the transformer to be saturated;
the A-phase current turn-off module is used for turning off the first preset direct current and switching on a winding of the A phase of the transformer at an optimal switching-on phase of the A-phase voltage, wherein the optimal switching-on phase is a phase in which a transient magnetic flux generated by switching-on and a saturated magnetic flux after the A phase is magnetized are offset;
the B-phase current charging module is used for injecting a second preset direct current into the B phase of the transformer so as to enable the magnetic flux of the B phase of the transformer to be saturated;
the B-phase current turn-off module is used for turning off the second preset direct current and switching on a winding of the B phase of the transformer at the optimal switching-on phase of the B-phase voltage;
and the C-phase switching-on module is used for switching on the winding of the C phase of the transformer at a preset time.
9. The transformer inrush current suppression device of claim 8, wherein the a-phase current charging module is specifically configured to:
injecting a first preset direct current into the phase A of the transformer based on a capacitor discharging mode to enable the magnetic flux of the phase A of the transformer to be saturated;
the B-phase current charging module is specifically configured to:
and injecting a second preset direct current into the phase B of the transformer 0.02s after the phase A of the transformer is switched on, so that the magnetic flux of the phase B of the transformer reaches saturation.
10. A transformer inrush current suppression device, the device comprising a processor and a memory:
the memory is used for storing program codes and transmitting the program codes to the processor;
the processor is configured to execute the transformer inrush current suppression method according to any one of claims 1 to 7 according to instructions in the program code.
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| Publication number | Priority date | Publication date | Assignee | Title |
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