Flexible DC converter valve submodule protection method, device, electronic equipment and medium

Abstract

The embodiment of the present invention relates to a method, device, electronic device and medium for high-frequency protection of a flexible DC converter valve submodule. The method comprises the steps of: calculating the number of times k1 and k2 of the submodule switch frequency signal is turned on within a first preset time Δt1 and a second preset time Δt2 respectively; calculating the effective value I of the bridge arm current within a third preset time Δt3; calculating the effective value I of the bridge arm current within a third preset time Δt4. arm According to the effective value of the current I arm The technical solution of the embodiment of the present invention can prevent the high-frequency protection signal of the submodule from malfunctioning and prevent the high-frequency signal from causing the submodule to fail, thereby realizing accurate protection of the submodule and improving the operating reliability of the flexible direct current converter valve.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of flexible direct current power transmission, and in particular to a flexible direct current converter valve submodule protection method, device, electronic equipment and medium. Background Art

[0002] Flexible high voltage direct current (MMC-HVDC) technology based on modular multilevel converter (MMC) has the advantages of independent regulation of active power and reactive power, low output voltage harmonic content, and can be connected to weak power grids and passive networks. In recent years, it has been widely used in the fields of asynchronous interconnection of AC power grids, distributed energy grid connection, and DC power grid. During the operation of the flexible DC converter valve, when a high-frequency signal appears in the submodule, the loss generated during the opening and closing of the submodule will cause the junction temperature of the IGBT device to rise rapidly. When the junction temperature exceeds the maximum tolerance junction temperature of the IGBT device, the IGBT device will be damaged. Therefore, when a high-frequency signal appears in the submodule of the flexible DC converter valve, a high-frequency protection strategy needs to be formulated to achieve effective protection of the submodule and improve the reliability of the operation of the flexible DC converter valve.

[0003] The junction temperature of the IGBT device in the power module is related to the switching frequency and the bridge arm current. When the bridge arm current is small, the switching loss is low. After the high frequency appears, the junction temperature of the IGBT device will not exceed the maximum tolerance junction temperature. Therefore, when the bridge arm current is small, the high-frequency protection is not enabled. The larger the bridge arm current, the lower the switching frequency that the IGBT device can tolerate. As the current increases, the high-frequency protection setting is dynamically adjusted to make the high-frequency protection more accurate and prevent false operation and unnecessary action. Summary of the invention

[0004] Based on the above situation of the prior art, the purpose of the embodiments of the present invention is to provide a flexible DC converter valve submodule protection method, device, electronic equipment and medium to achieve high-frequency protection of the flexible DC converter valve submodule and improve the operational reliability of the flexible DC converter valve.

[0005] To achieve the above object, according to one aspect of the present invention, a high-frequency protection method for a flexible DC converter valve submodule is provided, comprising the steps of:

[0006] S1, respectively calculating the number of times k1 and k2 of the switching frequency signal of the submodule is turned on within a first preset time Δt1 and a second preset time Δt2;

[0007] S2, calculate the effective value I of the bridge arm current within the third preset time Δt3 arm ;

[0008] S3, according to the effective value of the current Iarm Relationship with the set value, take corresponding protection measures:

[0009] S31, if I arm <A1, high frequency signal protection is not enabled;

[0010] S32, if A1<I arm ≤A2, adjust the setting values ​​of high frequency protection of stage I and stage II to N1 and N2 respectively;

[0011] If k1>N1, the power module is locked for a fourth preset time Δt4, and then the control command is received normally. If k1>N1 is still true at this time, the submodule is locked and the bypass is closed;

[0012] If k2>N2, the submodule is locked and the bypass is closed;

[0013] S33, if I arm >A2, adjust the setting values ​​of high frequency protection of stage I and stage II to N3 and N4;

[0014] If k1>N3, the power module is locked for a fourth preset time Δt4, and then a normal control instruction is received. If k1>N3 is still present at this time, the submodule is locked and the bypass is closed;

[0015] If k2>N4, the submodule is locked and the bypass is closed.

[0016] Among them, A1 is the bridge arm current setting value; N1, N2, N3 and N4 are all high-frequency protection setting values. Furthermore, the opening times k1 and k2 of the submodule switching frequency signal are calculated using a sliding window algorithm.

[0017] Furthermore, the effective value of the bridge arm current I arm The calculation is done using a sliding window algorithm.

[0018] Furthermore, the high frequency protection setting values ​​N1 and N2 are set to be, when the bridge arm current effective value I arm The value of A1<I arm ≤A2, when the simulated switching frequencies are N1 and N2 respectively, the junction temperature of the switching device cannot exceed the maximum tolerance of the IGBT device, and a margin is left.

[0019] Furthermore, the high frequency protection setting values ​​N3 and N4 are set to be, when the bridge arm current effective value I arm The value of A1<I arm When ≤A2, when the simulated switching frequencies are N3 and N4 respectively, the junction temperature of the switching device cannot exceed the maximum tolerance of the IGBT device, and a margin is left.

[0020] According to a second aspect of the present invention, a high-frequency protection device for a flexible DC converter valve submodule is provided, comprising:

[0021] A switching frequency signal calculation module, used to calculate the number of times k1 and k2 of switching on the submodule switching frequency signal within a first preset time Δt1 and a second preset time Δt2 respectively;

[0022] The bridge arm current effective value calculation module is used to calculate the bridge arm current effective value I within the third preset time Δt3 arm ;

[0023] The protection module is used to arm In relation to the set value, the protection method described in the first aspect of the present invention is adopted.

[0024] According to a third aspect of the present invention, an electronic device is provided, comprising a memory, a processor, and executable instructions stored in the memory and executable on the processor, wherein when the processor executes the program, the method described in the first aspect of the present invention is implemented.

[0025] According to a fourth aspect of the present invention, there is provided a computer-readable storage medium having computer-executable instructions stored thereon, wherein the executable instructions, when executed by a processor, implement the method as described in the first aspect of the present invention.

[0026] In summary, the embodiment of the present invention provides a method, device, electronic device and medium for high-frequency protection of a flexible DC converter valve submodule. The method comprises the steps of: calculating the number of times k1 and k2 of the submodule switch frequency signal is turned on within a first preset time Δt1 and a second preset time Δt2, respectively; calculating the effective value I of the bridge arm current within a third preset time Δt3; arm According to the effective value of the current I arm The technical solution of the embodiment of the present invention can prevent the high-frequency protection signal of the submodule from malfunctioning and prevent the high-frequency signal from causing the submodule to fail, thereby realizing accurate protection of the submodule and improving the operating reliability of the flexible direct current converter valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a flow chart of a high-frequency protection method for a flexible DC converter valve submodule according to an embodiment of the present invention;

[0028] Figure 2 This is a block diagram of the high-frequency protection device for the flexible DC converter valve submodule according to an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the junction temperature simulation waveform of the IGBT device at a switching frequency of 10kHz;

[0030] Figure 4 It is a schematic diagram of the junction temperature simulation waveform of the IGBT device with a switching frequency of 1kHz. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0032] The technical solution of the embodiment of the present invention is described in detail below with reference to the accompanying drawings. The embodiment of the present invention provides a high-frequency protection method for a flexible DC converter valve submodule. Figure 1 The flowchart of the protection method is shown in FIG. , and includes the following steps:

[0033] S1, respectively calculate the number of times k1 and k2 of the submodule switching frequency signal being turned on within the first preset time Δt1 and the second preset time Δt2. The number of times k1 and k2 of the submodule switching frequency signal being turned on can be calculated using a sliding window algorithm, and the effective value of the bridge arm current I arm The sliding window algorithm can be used for calculation.

[0034] S2, calculate the effective value I of the bridge arm current within the third preset time Δt3 arm .

[0035] S3, according to the effective value of the current I arm Relationship with the set value, take corresponding protection measures:

[0036] S31, if I arm <A1, high frequency signal protection is not enabled.

[0037] S32, if A1<I arm ≤A2, adjust the setting values ​​of high frequency protection of stage I and stage II to N1 and N2 respectively;

[0038] If k1>N1, the power module is locked for a fourth preset time Δt4, and then the control command is received normally. If k1>N1 is still true at this time, the submodule is locked and the bypass is closed;

[0039] If k2>N2, the submodule is locked and the bypass is closed;

[0040] S33, if I arm >A2, adjust the setting values ​​of high frequency protection of stage I and stage II to N3 and N4;

[0041] If k1>N3, the power module is locked for a fourth preset time Δt4, and then a normal control instruction is received. If k1>N3 is still present at this time, the submodule is locked and the bypass is closed;

[0042] If k2>N4, the submodule is locked and the bypass is closed.

[0043] Among them, A1 is the bridge arm current setting value; N1, N2, N3 and N4 are all high-frequency protection setting values, and they are different. The high-frequency protection setting values ​​N1 and N2 are set to, when the bridge arm current effective value I arm The value of A1<I arm ≤A2, the junction temperature of the switching device when the simulated switching frequency is N1 and N2 respectively, cannot exceed the maximum tolerance of the IGBT device, and a certain margin is left. The high-frequency protection setting values ​​N3 and N4 are set to, when the bridge arm current effective value I arm The value of A1<I arm ≤A2, the junction temperature of the switch device when the simulated switching frequencies are N3 and N4 respectively, cannot exceed the maximum tolerance of the IGBT device, and a certain margin is left. In the protection method provided in the embodiment of the present invention, the bridge arm current setting value and the high-frequency protection signal setting value can be determined by simulation based on the actual engineering system parameters and IGBT device parameters.

[0044] An embodiment of the present invention further provides a high-frequency protection device for a flexible DC converter valve submodule, comprising:

[0045] A switching frequency signal calculation module, used to calculate the number of times k1 and k2 of switching on the submodule switching frequency signal within a first preset time Δt1 and a second preset time Δt2 respectively;

[0046] The bridge arm current effective value calculation module is used to calculate the bridge arm current effective value I within the third preset time Δt3 arm ;

[0047] The protection module is used to arm In relation to the set value, the protection method described in the first aspect of the present invention is adopted.

[0048] The protection device may also include a submodule central control board, optical fibers and a valve control device. The central control board and the valve control device contain a memory, a processor and an executable computer processing program.

[0049] An embodiment of the present invention further provides an electronic device, comprising a memory, a processor, and executable instructions stored in the memory and executable on the processor, wherein when the processor executes the program, the method described in the above embodiment of the present invention is implemented.

[0050] An embodiment of the present invention further provides a computer-readable storage medium on which computer-executable instructions are stored. When the executable instructions are executed by a processor, the method described in the above embodiment of the present invention is implemented.

[0051] The following is a description with reference to specific embodiments.

[0052] The block diagram of the high-frequency protection device for the flexible direct current converter valve submodule provided by the present invention is as follows: Figure 2 As shown, the protection method proposed in the embodiment of the present invention is applicable to half-bridge and full-bridge submodules. The following takes a ±420kV / 1250MW flexible direct current transmission project as an example to illustrate the high-frequency protection method and device of the flexible direct current converter valve submodule. The steps are as follows:

[0053] (1) Calculate the submodule switching frequency signals of 10ms and 100ms as k1 and k2;

[0054] (2) Calculate the effective current value Iarm for 100ms;

[0055] (3) Through simulation calculation, when the bridge arm current Iarm≤100Arms, even if a high-frequency signal of 20kHz appears, the junction temperature of the switching device is still within the maximum allowable junction temperature range. Therefore, the setting value of A1 is set to 100Arms. When the bridge arm current Iarm<100Arms, the high-frequency protection is not enabled.

[0056] (4) Through simulation calculation, when the bridge arm current is 100Arms<Iarm≤600Arms, the switching frequency signal is >8kHz for 10ms, or the switching frequency signal is >2kHz for 100ms, the junction temperature of the switch device will exceed the maximum allowable junction temperature. Then set A2 to 600Arms, N1 to 8kHz, and N2 to 2kHz. In the normal allowable process, the values ​​of k1 and k2 are about 100Hz and will not exceed the set values. When a fault condition occurs, a high-frequency signal will appear in the flexible direct current valve submodule. When k1>8kHz appears, it will be locked for 1ms first, and then the control command will be received again. If k1>8kHz still exists, the valve control device will send a control command to the central control board, so that the central control board will lock the submodule and close the bypass. When k2>2kHz appears, the valve control device will directly send a control command to the central control board, so that the central control board will lock the submodule and close the bypass.

[0057] (4) Through simulation calculation, when the bridge arm current Iarm>600Arms, the 10ms switching frequency signal>5kHz, or the 100ms switching frequency signal>1kHz, the junction temperature of the switch device will exceed the maximum allowable junction temperature, so the setting value N3 is set to 5kHz and the setting value N4 is set to 1kHz. In the normal allowable process, the values ​​of k1 and k2 are about 100Hz and will not exceed the setting value. When a fault condition occurs, a high-frequency signal will appear in the flexible direct current valve submodule. When k1>5kHz appears, it will be locked for 1ms first, and then the control command will be received again. If k1>5kHz still exists, the valve control device will send a control command to the central control board, so that the central control board will lock the submodule and close the bypass. When k2>1kHz appears, the valve control device will directly send a control command to the central control board, so that the central control board will lock the submodule and close the bypass.

[0058] Figure 3 The figure shows the schematic diagram of the junction temperature simulation waveform of the 10kHz switching frequency IGBT device. Figure 4 The figure shows a schematic diagram of the junction temperature simulation waveform of an IGBT device with a switching frequency of 1kHz.

[0059] In summary, the embodiments of the present invention relate to a method, device, electronic device and medium for high-frequency protection of a flexible DC converter valve submodule. The method comprises the steps of: calculating the number of times k1 and k2 of the submodule switch frequency signal is turned on within a first preset time Δt1 and a second preset time Δt2, respectively; calculating the effective value I of the bridge arm current within a third preset time Δt3. arm According to the effective value of the current I arm The technical solution of the embodiment of the present invention can prevent the high-frequency protection signal of the submodule from malfunctioning and prevent the high-frequency signal from causing the submodule to fail, thereby realizing accurate protection of the submodule and improving the operating reliability of the flexible direct current converter valve.

[0060] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A high-frequency protection method for a flexible DC converter valve submodule, characterized in that: Includes steps: S1, respectively calculating the number of times k1 and k2 of the submodule switching frequency signal being turned on within a first preset time Δt1 and a second preset time Δt2; the second preset time Δt2 is greater than the first preset time Δt1; S2, calculate the effective value I of the bridge arm current within the third preset time Δt3 arm ; S3, according to the effective value of the current I arm Relationship with the set value, take corresponding protection measures: S31, if I arm <A1, high frequency signal protection is not enabled; S32, if A1<I arm ≤A2, adjust the setting values ​​of high frequency protection of stage I and stage II to N1 and N2 respectively; If k1>N1, the power module is locked for a fourth preset time Δt4, and then the control command is received normally. If k1>N1 is still true at this time, the submodule is locked and the bypass is closed; If k2>N2, the submodule is locked and the bypass is closed; S33, if I arm >A2, adjust the setting values ​​of high frequency protection of stage I and stage II to N3 and N4; If k1>N3, the power module is locked for a fourth preset time Δt4, and then a normal control instruction is received. If k1>N3 is still present at this time, the submodule is locked and the bypass is closed; If k2>N4, the submodule is locked and the bypass is closed; Among them, A1 and A2 are the arm current setting values; N1, N2, N3 and N4 are all high-frequency protection setting values, and they are different.

2. The protection method according to claim 1, characterized in that: Bridge arm current effective value I arm The sliding window algorithm is used to calculate the number of times k1 and k2 of the switching frequency signal of the submodule is turned on and off.

3. The protection method according to claim 2, characterized in that: The high frequency protection setting values ​​N1 and N2 are set to be, when the bridge arm current effective value I arm The value of A1<I arm ≤A2, when the simulated switching frequencies are N1 and N2 respectively, the junction temperature of the switching device cannot exceed the maximum tolerance of the IGBT device, and a margin is left.

4. The protection method according to claim 2, characterized in that: The high frequency protection setting values ​​N3 and N4 are set to be, when the bridge arm current effective value I arm The value of I arm >A2, when the simulated switching frequencies are N3 and N4 respectively, the junction temperature of the switching device cannot exceed the maximum tolerance of the IGBT device, and a margin is left.

5. A high-frequency protection device for a flexible DC converter valve submodule, characterized in that: include: A switching frequency signal calculation module, used to calculate the number of times k1 and k2 of switching on the submodule switching frequency signal within a first preset time Δt1 and a second preset time Δt2 respectively; The bridge arm current effective value calculation module is used to calculate the bridge arm current effective value I within the third preset time Δt3 arm ; The protection module is used to arm In relation to the set value, a protection method as described in any one of claims 1 to 4 is adopted.

6. An electronic device comprising a memory, a processor, and executable instructions stored in the memory and executable on the processor, characterized in that: When the processor executes the executable instructions, the method according to any one of claims 1 to 4 is implemented.

7. A computer-readable storage medium having computer-executable instructions stored thereon, characterized in that: When the executable instructions are executed by a processor, the method according to any one of claims 1 to 4 is implemented.

Images