CN113834960A - Protection voltage calculation method of submodule passive breakdown protection device - Google Patents
Protection voltage calculation method of submodule passive breakdown protection device Download PDFInfo
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- CN113834960A CN113834960A CN202010586094.0A CN202010586094A CN113834960A CN 113834960 A CN113834960 A CN 113834960A CN 202010586094 A CN202010586094 A CN 202010586094A CN 113834960 A CN113834960 A CN 113834960A
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- 238000004364 calculation method Methods 0.000 title claims abstract description 12
- 238000000034 method Methods 0.000 claims abstract description 12
- 239000003990 capacitor Substances 0.000 claims description 13
- 238000010586 diagram Methods 0.000 description 3
- 230000002159 abnormal effect Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0084—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring voltage only
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/006—Calibration or setting of parameters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/20—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess voltage
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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
- H02H7/10—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 converters; for rectifiers
- H02H7/12—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 converters; for rectifiers for static converters or rectifiers
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
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- General Physics & Mathematics (AREA)
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Abstract
The invention discloses a protection voltage calculation method of a sub-module passive breakdown protection device. According to the method, the maximum voltage value under the operating condition of the submodule and the breakdown voltage of the submodule power device are combined with the peak current charging voltage increment of a bridge arm in the switching-on period of the submodule bypass switch to obtain the protection voltage range calculation method of the submodule passive breakdown protection device, the protection voltage value of the submodule passive breakdown protection device is guided, and the design reasonability and accuracy of the modular multilevel converter are improved.
Description
Technical Field
The invention relates to the technical field of flexible direct current power transmission and distribution, in particular to a protection voltage calculation method of a submodule passive breakdown protection device.
Background
The modular multilevel converter is connected in series through modular and standardized sub-modules, and a sub-module alternating current port is generally connected with a bypass switch and a passive breakdown protection device in parallel. In the operation process of the sub-module, if the sub-module fails, the sub-module bypass switch needs to be switched on, so that the sub-module is in a short-circuit state, and the stable operation of the modular multilevel converter is ensured. The bypass switch is of a mechanical structure, when the bypass switch fails to operate, the current of the modular multilevel converter continuously boosts the fault submodule until the submodule is subjected to overvoltage explosion, and therefore when the bypass switch fails to operate, the modular multilevel converter stops operating.
Aiming at the problems, a method for connecting a passive breakdown protection device in parallel at a submodule alternating current port of a modular multilevel converter is generally adopted at present, and meanwhile, the passive breakdown protection device with accurately controllable breakdown voltage is selected, so that overvoltage breakdown occurs when the voltage of the submodule alternating current port rises to the protection voltage of the submodule passive breakdown protection device when a bypass switch of the submodule fails, the passive breakdown protection device forms a short-circuit through-current state, and the modular multilevel converter is not stopped.
A protection voltage value of a submodule passive breakdown protection device of the modular multilevel converter is not calculated at present, an empirical value means is generally adopted, and a scientific calculation method and basis are lacked. Therefore, a protection voltage calculation method of the sub-module passive breakdown protection device is needed to guide the protection voltage value of the sub-module passive breakdown protection device and improve the design rationality and accuracy of the modular multilevel converter.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides a protection voltage calculation method of a sub-module passive breakdown protection device, which guides the value of the protection voltage of the sub-module passive breakdown protection device and improves the design rationality and accuracy of the modular multilevel converter.
In order to achieve the purpose, the invention adopts the technical scheme that:
the protection voltage calculation method of the submodule passive breakdown protection device comprises the following steps:
calculating an overvoltage protection action value under the operation condition of the sub-module power device, and determining the closing time of the sub-module power device protection bypass switch;
calculating the voltage rise caused by the capacitor charging of the sub-module power device based on the closing time of the sub-module power device protection bypass switch;
and calculating the protection voltage range of the sub-module power device in the passive breakdown protection device based on the overvoltage protection action value under the operation condition of the sub-module power device and the voltage rise caused by the capacitor charging of the sub-module power device.
Further, the calculating an overvoltage protection action value under the operating condition of the sub-module power device includes:
Up＝kp*Unom，
wherein, UpFor overvoltage protection action value, kpFor overvoltage protection safety factor, UnomThe maximum voltage value under the operation condition of the sub-module power device is obtained.
Further, the calculating a voltage rise caused by the charging of the sub-module power device capacitor based on the closing time of the sub-module power device protection bypass switch includes:
wherein, Δ u is the voltage rise caused by the charging of the sub-module power device capacitor, C is the sub-module power device capacitance value, Δ t is the closing time of the sub-module power device protection bypass switch, t0For the time of peak current i under steady-state operation of the converter valvebThe current of the bridge arm where the sub-submodule power device is located.
Further, the calculating of the protection voltage range of the passive breakdown protection device of the sub-module power device based on the overvoltage protection action value under the operation condition of the sub-module power device and the voltage rise caused by the capacitor charging of the sub-module power device includes:
Up≤Ux≤min(UBR，Up+Δu)，
wherein, UpFor overvoltage protection action value, UxThe protection voltage of the sub-module power device is passively broken down, and the delta U is the voltage rise, U, caused by charging the sub-module power device capacitorBRThe breakdown voltage value of the submodule power device is shown.
Furthermore, the sub-module power device comprises at least one passive breakdown protection device and at least one protection bypass switch, and the passive breakdown protection device and the protection bypass switch are connected in parallel to the output port of the sub-module power device.
Furthermore, the sub-module power device is an IGBT, an IEGT, a thyristor full-control or half-control device.
Furthermore, the sub-module power device passive breakdown protection device is a diode, thyristor full-control or half-control device.
Furthermore, the operation conditions of the sub-module power device comprise a steady-state operation condition and a fault condition, and the fault condition comprises an alternating current side fault, a direct current side fault and a converter body fault.
The invention has the beneficial effects that:
the invention provides a protection voltage calculation method of a sub-module passive breakdown protection device, which guides the value of the protection voltage of the sub-module passive breakdown protection device of a modular multilevel converter and improves the design rationality and accuracy of the modular multilevel converter.
Drawings
Fig. 1 is a schematic diagram of a modular multilevel converter;
FIG. 2 is a schematic diagram of a method for calculating a protection voltage of a sub-module passive breakdown protection device according to the present invention;
FIG. 3 is a schematic diagram of bridge arm current values according to the present invention.
Detailed Description
The invention is further described below. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
Referring to fig. 1, the modular multilevel converter includes at least one submodule connected in series, the submodule is in a half-bridge or full-bridge topology structure, and an alternating current port of the submodule is subjected to bypass protection by using a bypass switch K and a passive breakdown protection device SCR.
The embodiment of the invention provides a method for calculating the protection voltage of a sub-module passive breakdown protection device, which comprises the following steps of:
step 1: determining the highest voltage value U under the operating condition of the submodulenomAnd calculating the overvoltage protection action value of the submodule:
Up＝kp*Unom，
wherein k ispFor the safety factor of overvoltage protection, about 1.1 is generally adopted.
Step 2: determining breakdown voltage value U of submodule power deviceBRIf the sub-module adopts 3300V power device, the data specification of the power device is inquired, and the U isBR3300V.
And step 3: determining the closing time delta t of the sub-module bypass switch K, wherein the closing time of the bypass switch K is 3-5 ms generally;
as shown in FIG. 3, the peak current under the steady-state operation condition of the converter valve is taken as the central point and is recorded as t0Time, before and after
Bridge arm current i in one segment of time rangebAnd calculating the voltage rise delta u caused by the charging of the bridge arm current to the sub-module capacitor:
where C is the sub-module capacitance.
And 4, step 4: protection voltage range U of SCR of calculation submodule passive breakdown protection devicex：
Up≤Ux≤min(UBR，Up+Δu)，
Wherein, min (U)BR，Up+ Δ U) is UBRAnd UpMinimum value of + Δ u.
Specifically, in the embodiment of the invention, the SCR of the sub-module passive breakdown protection device is a diode, a thyristor full-control or half-control device, and the sub-module power device is an IGBT, an IEGT, a thyristor full-control or half-control device.
Specifically, the sub-module in the embodiment of the present invention includes at least one passive breakdown protection device SCR and at least one protection bypass switch K, where the passive breakdown protection device SCR and the protection bypass switch K are connected in parallel to the sub-module output port.
Specifically, the operation conditions of the sub-modules in the embodiment of the present invention include a steady-state operation condition and a fault condition, where the fault condition includes an ac side fault, a dc side fault, a converter body fault, and the like.
Specifically, in the embodiment of the invention, the bypass switch K of the sub-module starts to act after receiving a closing command, the main contact of the bypass switch is conducted after the closing time delta t under a normal condition, the main contact of the bypass switch cannot be conducted under an abnormal condition, and the abnormal condition comprises a fault of a body of the bypass switch K and a fault of an energy storage loop of the bypass switch.
Specifically, in the embodiment of the invention, the voltage of the sub-module passive breakdown protection device SCR at the sub-module alternating current port is lower than the protection voltage U of the SCRxIs not conducted, and the voltage at the AC port of the sub-module is higher than the protection voltage UxBreakdown conduction due to overvoltage occurs.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.
Claims (8)
1. The protection voltage calculation method of the submodule passive breakdown protection device is characterized by comprising the following steps:
calculating an overvoltage protection action value under the operation condition of the sub-module power device, and determining the closing time of the sub-module power device protection bypass switch;
calculating the voltage rise caused by the capacitor charging of the sub-module power device based on the closing time of the sub-module power device protection bypass switch;
and calculating the protection voltage range of the sub-module power device in the passive breakdown protection device based on the overvoltage protection action value under the operation condition of the sub-module power device and the voltage rise caused by the capacitor charging of the sub-module power device.
2. The method for calculating the protection voltage of the submodule passive breakdown protection device according to claim 1, wherein the step of calculating the overvoltage protection action value under the operation condition of the submodule power device comprises the following steps:
Up＝kp*Unom，
wherein, UpFor overvoltage protection action value, kpFor overvoltage protection safety factor, UnomThe maximum voltage value under the operation condition of the sub-module power device is obtained.
3. The method for calculating the protection voltage of the sub-module passive breakdown protection device according to claim 1, wherein the calculating the voltage rise caused by the charging of the sub-module power device capacitor based on the closing time of the sub-module power device protection bypass switch comprises:
wherein, Δ u is the voltage rise caused by the charging of the sub-module power device capacitor, C is the sub-module power device capacitance value, Δ t is the closing time of the sub-module power device protection bypass switch, t0For the time of peak current i under steady-state operation of the converter valvebThe current of the bridge arm where the sub-submodule power device is located.
4. The method for calculating the protection voltage of the sub-module passive breakdown protection device according to claim 1, wherein the calculating the protection voltage range of the sub-module power device passive breakdown protection device based on the overvoltage protection action value under the operation condition of the sub-module power device and the voltage rise caused by the capacitor charging of the sub-module power device comprises:
Up≤Ux≤min(UBR，Up+Δu)，
wherein, UpFor overvoltage protection action value, UxThe protection voltage of the sub-module power device is passively broken down, and the delta U is the voltage rise, U, caused by charging the sub-module power device capacitorBRThe breakdown voltage value of the submodule power device is shown.
5. The method for calculating the protection voltage of the sub-module passive breakdown protection device according to any one of claims 1 to 4, wherein the sub-module power device comprises at least one passive breakdown protection device and at least one protection bypass switch, and the passive breakdown protection device and the protection bypass switch are connected in parallel to a sub-module power device output port.
6. The method for calculating the protection voltage of the sub-module passive breakdown protection device according to claim 5, wherein the sub-module power device is an IGBT, an IEGT, a thyristor-type fully-controlled or semi-controlled device.
7. The method for calculating the protection voltage of the sub-module passive breakdown protection device according to claim 5, wherein the sub-module power device passive breakdown protection device is a diode, thyristor or semi-controlled device.
8. The method for calculating the protection voltage of the submodule passive breakdown protection device according to any one of claims 1 to 4, wherein the submodule power device operation conditions comprise steady-state operation conditions and fault conditions, and the fault conditions comprise an alternating current side fault, a direct current side fault and a converter body fault.
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| CN202010586094.0A CN113834960A (en) | 2020-06-24 | 2020-06-24 | Protection voltage calculation method of submodule passive breakdown protection device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115372815A (en) * | 2022-08-29 | 2022-11-22 | 广东电网有限责任公司广州供电局 | Device, method and medium for testing closing and bouncing time of sub-module bypass switch |
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