CN118214067A - MMC-UPFC fault ride-through device and method based on stepped and hysteresis switching - Google Patents
MMC-UPFC fault ride-through device and method based on stepped and hysteresis switching Download PDFInfo
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- CN118214067A CN118214067A CN202410207933.1A CN202410207933A CN118214067A CN 118214067 A CN118214067 A CN 118214067A CN 202410207933 A CN202410207933 A CN 202410207933A CN 118214067 A CN118214067 A CN 118214067A
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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
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
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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
- H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
- H02H9/025—Current limitation using field effect transistors
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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
- H02J3/12—Circuit arrangements for AC mains or AC distribution networks for adjusting voltage in AC networks by changing a characteristic of the network load
- H02J3/16—Circuit arrangements for AC mains or AC distribution networks for adjusting voltage in AC networks by changing a characteristic of the network load by adjustment of reactive power
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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
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/50—Controlling the sharing of the out-of-phase component
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- Power Engineering (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
本发明涉及一种基于阶梯式和滞环投切的MMC‑UPFC故障穿越装置与方法，基于阶梯式和滞环原理控制分布式限流模块的投切，实现MMC‑UPFC故障穿越。故障穿越装置包括：并联变压器、并联侧MMC、串联变压器、串联侧MMC以及分布式限流模块。故障穿越方法包括：根据直流母线基准值和直流母线电流值控制故障穿越装置的运行模式。本发明提供的基于阶梯式和滞环投切的MMC‑UPFC故障穿越装置及方法，通过检测直流母线电流，按照阶梯式和滞环原则控制分布式限流模块的投切，实现MMC‑UPFC故障穿越。在MMC‑UPFC所在交流母线发生短路故障时，能够抑制通过直流母线馈入并联侧MMC的短路电流，确保并联侧MMC不会过流闭锁，MMC‑UPFC转入STATCOM模块继续运行，继续发出无功功率，维持并网点电压稳定。
The present invention relates to a MMC-UPFC fault ride-through device and method based on step-type and hysteresis switching, which controls the switching of distributed current limiting modules based on step-type and hysteresis principles to achieve MMC-UPFC fault ride-through. The fault ride-through device includes: a parallel transformer, a parallel-side MMC, a series transformer, a series-side MMC, and a distributed current limiting module. The fault ride-through method includes: controlling the operation mode of the fault ride-through device according to a DC bus reference value and a DC bus current value. The MMC-UPFC fault ride-through device and method based on step-type and hysteresis switching provided by the present invention detect the DC bus current, control the switching of the distributed current limiting module according to the step-type and hysteresis principles, and achieve MMC-UPFC fault ride-through. When a short-circuit fault occurs in the AC bus where the MMC-UPFC is located, the short-circuit current fed into the parallel-side MMC through the DC bus can be suppressed to ensure that the parallel-side MMC will not be over-current locked, and the MMC-UPFC switches to a STATCOM module to continue to operate, continue to generate reactive power, and maintain the voltage stability of the grid connection point.
Description
Technical Field
The invention relates to a stepped and hysteresis switching-based MMC-UPFC fault ride-through device and method, and belongs to the technical field of electric power.
Background
The unified power flow controller (Unified Power Flow Controller, UPFC) is the most comprehensive flexible alternating current transmission (Flexible AC Transmission Systems, FACTS) device so far, and can respectively or simultaneously realize different functions of parallel compensation, series compensation, phase shift, terminal voltage regulation and the like, thereby realizing the rapid independent control of active power and reactive power of a line. The modularized multi-level converter (modular multilevel converter, MMC) has the characteristics of modularized structure, redundant configuration, expandable power and the like. These advantages have led to widespread use of MMCs in high voltage high power scenarios, such as UPFC.
When the ac bus where the MMC-UPFC device is located has a short circuit fault, the fault current will be coupled to the valve side through the series transformer, resulting in an over-current blocking of the MMC on the series side, and due to the inherent delay in the action of the thyristor bypass switch (Thyristor Bypass Switch, TBS), the short circuit current is still continuously fed in during this period, flows through the blocked MMC on the series side, is fed into the MMC on the parallel side through the dc bus, resulting in an over-current blocking of the MMC on the parallel side, and the MMC-UPFC completely exits operation. If the parallel-side MMC cannot be blocked excessively, the MMC-UPFC can be converted into a STATCOM working mode, reactive power can be emitted, and the voltage stability of the grid-connected point is maintained as far as possible. Therefore, there is a need to develop an MMC-UPFC fault ride-through scheme that can ensure that the parallel side MMC does not over-current during a fault.
Disclosure of Invention
In order to overcome the problems in the prior art, the invention provides the MMC-UPFC fault ride-through device and the method which can enable the MMC on the parallel side to be blocked in an overcurrent manner, can convert the MMC-UPFC into a STATCOM working mode, can send out reactive power, maintain the voltage stability of a grid-connected point as far as possible and can ensure that the MMC on the parallel side is not overcurrent during the fault period.
In order to solve the technical problems, a first technical scheme provided by the invention is as follows: MMC-UPFC fault ride-through device based on cascaded and hysteresis switching includes: the device comprises a parallel transformer, a parallel side MMC, a series transformer, a series side MMC and a distributed current limiting module;
The parallel side MMC is integrated into an alternating current bus in a parallel mode through the parallel transformer; the series-side MMC is connected in series with an alternating current bus through the series transformer; the parallel-side MMC and the serial-side MMC are connected in a back-to-back manner through a direct current bus; the distributed current limiting modules are serially connected into the direct current bus; the distributed current limiting module is formed by connecting an IGBT, a diode and a current limiting resistor in parallel, wherein the conducting directions of the IGBT and the diode are opposite, and the conducting direction of the IGBT is from the series-connection side MMC to the parallel-connection side MMC;
the low-voltage side winding of the series transformer is connected with a thyristor bypass switch in parallel; and the thyristor bypass switch can bypass the series-side MMC after being conducted.
The scheme is further improved as follows: the number of the distributed current limiting modules connected in series on the direct current bus is 9, and the current limiting resistance is 1.1 ohms.
In order to solve the technical problems, a second technical scheme provided by the invention is as follows: according to the fault ride-through method of the MMC-UPFC fault ride-through device based on the stepped and hysteresis switching in the scheme, the operation mode of the fault ride-through device is controlled according to the direct current bus current reference value and the direct current bus current actual value; when an alternating current bus breaks down, fault current is coupled to a valve side through a series transformer, bridge arm current of the MMC at the series side exceeds an overcurrent protection value and enters a blocking state, before a bypass switch of a thyristor is conducted, short-circuit current can still be fed into the MMC at the parallel side through a direct current bus, the direct current bus current rises to a current limiting resistance input value, an IGBT of a corresponding distributed current limiting module is turned off, a current limiting resistor is connected to the direct current bus to inhibit rising of the direct current bus current, and after the direct current bus current falls to a current limiting resistance cut-off value, the IGBT of the corresponding distributed current limiting module is turned on again, and the current limiting resistor is bypassed.
The scheme is further improved as follows: the steps of controlling the operation mode of the fault traversing device are as follows:
Step 1: setting an input value I dc_inserted_n of the current limiting resistor and a bypass value I dc_bypassed_n of the current limiting resistor based on a stepped and hysteresis principle according to a preset direct current bus current reference value I dc_base; wherein n is the serial number of the distributed current limiting module;
Step 2: and acquiring a direct current bus current actual value I dc_real, comparing the obtained direct current bus current actual value with I dc_inserted_n and I dc_bypassed_n, determining IGBT on-off states of all the distributed current limiting modules, and outputting the IGBT on-off states.
The scheme is further improved as follows: i dc_base in the step 1 is 1200A.
The scheme is further improved as follows: the input value I dc_inserted_n of the current-limiting resistor and the bypass value I dc_bypassed_n of the current-limiting resistor in the step 1 are calculated according to the following formulas,
I dc_inserted_n＝Idc_base+(n-1)*100,Idc_bypassed_n＝Idc_inserted_n -200; wherein n is the serial number of the distributed current limiting module.
The scheme is further improved as follows: in the step 2, the actual value I dc_real of the current direct current bus is sequentially compared with the input value and the bypass value of all the distributed current limiting modules, if I dc_real exceeds I dc_inserted_n, the IGBTs in the corresponding distributed current limiting modules are switched to be in an off state, if I dc_real is smaller than I dc_bypassed_n, the IGBTs in the corresponding distributed current limiting modules are switched to be in an on state, and if I dc_real is between I dc_inserted_n and I dc_bypassed_n, the on-off state of the IGBTs in the corresponding distributed current limiting modules is not changed.
According to the MMC-UPFC fault ride-through device and method based on the stepwise and hysteresis switching, the switching of the distributed current limiting module is controlled according to the stepwise and hysteresis principle by detecting the direct current bus current, so that the MMC-UPFC fault ride-through is realized. When the alternating current bus where the MMC-UPFC is located has short circuit fault, short circuit current is coupled to the valve side through the series transformer, the MMC on the series side is subjected to overcurrent blocking, when the current value of the direct current bus exceeds a set limit value, the IGBT in the corresponding distributed current limiting module is turned off, the current limiting resistor in the corresponding current limiting module is connected into the direct current bus, and further fault current fed into the MMC on the parallel side through the direct current bus is restrained, the MMC on the parallel side cannot be subjected to overcurrent blocking, and at the moment, the MMC-UPFC is switched into a STATCOM working mode, and reactive power can be emitted. Therefore, when the alternating current bus where the MMC-UPFC is located has a short circuit fault, the invention can inhibit short circuit current fed into the MMC at the parallel side through the direct current bus, ensure that the MMC at the parallel side cannot be blocked by overcurrent, and the MMC-UPFC is transferred into the STATCOM module to continue to operate, continue to send reactive power and maintain stable voltage of the grid-connected point.
Drawings
The invention is further described below with reference to the accompanying drawings.
Fig. 1 is a schematic circuit topology of a preferred embodiment of the present invention.
Fig. 2 is a control structure diagram of a preferred embodiment of the present invention.
Fig. 3 is a graph comparing simulated waveforms of dc bus current in a fault-free ride through condition and a condition in which a preferred embodiment of the present invention is applied.
FIG. 4 is a simulated waveform diagram of the number of bypasses of the distributed current limiting module in accordance with a preferred embodiment of the present invention.
Fig. 5 is a simulated waveform diagram of the current of the MMC bridge arm at the parallel side in the fault-free ride through state.
Fig. 6 is a simulated waveform diagram of the current of the parallel side MMC bridge arm in a state where a preferred embodiment of the present invention is applied.
Fig. 7 is a waveform diagram of the output reactive power of the MMC on the parallel side in a state of applying a preferred embodiment of the present invention.
Detailed Description
Examples: the MMC-UPFC fault ride-through device based on step-type and hysteresis switching in this embodiment is shown in FIG. 1, and includes: the parallel transformer, the parallel side MMC, the series transformer and the series side MMC. The parallel side MMC is incorporated into the ac bus in parallel form by a parallel transformer. The series-connection side MMC is connected in series with the alternating current bus through the series-connection transformer, and the parallel-connection side MMC and the series-connection side MMC are connected in a back-to-back mode through a direct current bus. A Thyristor Bypass Switch (TBS) is connected on the low-voltage side of the series transformer for bypassing the series side MMC in an emergency situation.
When the alternating current bus where the MMC-UPFC device is located has a short circuit fault, the basic fault characteristics of the MMC-UPFC device are as follows: the fault current will couple to the valve side through the series transformer, resulting in series side MMC over-current blocking, during which the short circuit current is still continuously fed, flowing through the blocked series side MMC, feeding into the parallel side MMC through the dc bus, resulting in parallel side MMC over-current blocking, MMC-UPFC completely exiting operation due to the inherent delay of TBS action.
In order to avoid the above-mentioned over-current blocking of the parallel side MMC under the fault condition, in this embodiment, n distributed current limiting modules are connected in series on the dc positive bus, as shown in LM1 to LMn in fig. 1. In this embodiment, the number of the distributed current limiting modules is 9, and the resistance value of the current limiting resistor in each distributed current limiting module is 1.1 ohm.
The distributed current limiting module is formed by connecting an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT), a diode and a current limiting resistor in parallel, wherein the conducting directions of the IGBT and the diode are opposite, and the conducting direction of the IGBT is from a series-connection side MMC to a parallel-connection side MMC; in fig. 1, T represents an IGBT, D represents a diode, and RCL represents a current limiting resistor.
Fig. 2 is a control structure diagram of the MMC-UPFC fault ride-through method based on ladder-type and hysteresis switching in the present embodiment. Firstly, setting an input value I dc_inserted_n of a current-limiting resistor and a bypass value I dc_bypassed_n of the current-limiting resistor based on a stepped and hysteresis principle according to a preset direct-current bus current reference value I dc_base, wherein the specific steps are as follows: 1) The input value I dc_inserted_n of the current-limiting resistor is set as I dc_inserted_n＝Idc_base + (n-1) 100; 2) The current limiting resistor bypass value I dc_bypassed_n is set to I dc_bypassed_n＝Idc_inserted_n -200. And then acquiring the actual value I dc_real of the direct-current bus current, comparing the actual value I dc_inserted_n with the actual value I dc_bypassed_n of the direct-current bus current, wherein the IGBT on-off state of the distributed current limiting module is expressed as follows: 1) switching the IGBTs in the respective distributed current limiting modules to an off state if I dc_real exceeds I dc_inserted_n, 2) switching the IGBTs in the respective distributed current limiting modules to an on state if I dc_real is less than I dc_bypassed_n, 3) if I dc_real is between I dc_inserted_n and I dc_bypassed_n, the on-off state of the IGBTs in the corresponding distributed current limiting modules is not changed.
In order to illustrate the effect of the MMC-UPFC fault ride-through device and method based on stepped and hysteresis switching in this embodiment, the following verification is performed.
Fig. 3 to 7 are simulation waveforms of the ac bus of the MMC-UPFC device of the present embodiment when a three-phase short-circuit fault occurs at the point k in fig. 1. The time of occurrence of the fault was 4s and the duration of the fault was 0.5s.
FIG. 3 is a comparison chart of simulation waveforms of DC bus current in the case of no fault ride through and the case of applying the fault ride through device and method according to the present embodiment. The comparison result shows that under the condition of no fault ride-through, after the fault occurs, the current value of the direct current bus is continuously increased, so that the MMC on the parallel side is blocked in an overcurrent manner; when the fault ride-through device and the fault ride-through method provided by the embodiment are applied, when the direct current bus exceeds the input value of the current limiting resistor of the distributed current limiting module, the IGBT in the corresponding distributed current limiting module is turned off, the current limiting resistor is connected into the direct current bus, the rising amplitude of the current of the direct current bus is restrained, the MMC on the parallel side cannot be subjected to overcurrent locking, the system is switched into a STATCOM mode, reactive power can be sent out, and the voltage stability of a grid-connected point can be maintained as much as possible.
Fig. 4 is a simulated waveform diagram of the number of current limiting resistors connected in the distributed current limiting module under the situation of applying the fault ride-through device and the fault ride-through method of the present embodiment. Simulation results show that when the MMC-UPFC device normally operates, the direct current bus current is smaller than the input value of the current-limiting resistor of the distributed current-limiting module, all IGBTs in the distributed current-limiting module are conducted, the current-limiting resistor is bypassed, when faults occur, the direct current bus current exceeds the input value of the current-limiting resistor of the distributed current-limiting module, the IGBTs in the corresponding distributed current-limiting module are turned off, the current-limiting resistor is connected, after the TBS is conducted, the direct current bus current drops, and when the direct current bus is lower than the bypass value of the current-limiting resistor of the distributed current-limiting module, the IGBTs in the corresponding distributed current-limiting module are conducted, and the current-limiting resistor bypasses.
Fig. 5 is a simulated waveform diagram of a parallel-side MMC bridge arm current in a fault-free ride-through situation, fig. 6 is a simulated waveform diagram of a parallel-side MMC bridge arm current in a fault-ride-through device and method of the present embodiment, and fig. 7 is a waveform diagram of a parallel-side MMC output reactive power in a fault-ride-through device and method of the present embodiment. The simulation waveforms in fig. 3 to 7 show that when the ac bus where the MMC-UPFC device is located has a short circuit fault, the MMC-UPFC fault ride-through device and method based on the distributed current limiting module of the embodiment are applied, the MMC on the parallel side cannot be blocked by overcurrent, the system is switched into a STATCOM mode, reactive power can be sent out, and the voltage stability of the grid-connected point can be maintained as much as possible.
The verification result shows that the MMC-UPFC fault ride-through device and the method based on the stepped and hysteresis switching can ensure that the MMC-UPFC device is not blocked excessively at the parallel side when the alternating current bus where the MMC-UPFC device is located has a short circuit fault.
According to the MMC-UPFC fault ride-through device and method based on the stepwise and hysteresis switching, the switching of the distributed current limiting module is controlled according to the stepwise and hysteresis principle by detecting the direct current bus current, so that the MMC-UPFC fault ride-through is realized. When the alternating current bus where the MMC-UPFC is located has short circuit fault, short circuit current is coupled to the valve side through the series transformer, the MMC on the series side is subjected to overcurrent blocking, when the current value of the direct current bus exceeds a set limit value, the IGBT in the corresponding distributed current limiting module is turned off, the corresponding current limiting resistor is connected into the direct current bus, the current limiting resistor is connected into the direct current bus, fault current fed into the MMC on the parallel side through the direct current bus is further inhibited, the MMC on the parallel side is not subjected to overcurrent blocking, and at the moment, the MMC-UPFC is switched into a STATCOM working mode, and reactive power can be emitted. Therefore, when the alternating current bus where the MMC-UPFC is located has a short circuit fault, the device and the method can inhibit short circuit current fed into the MMC at the parallel side through the direct current bus, ensure that the MMC at the parallel side cannot be blocked by overcurrent, and the MMC-UPFC is transferred into the STATCOM module to continue to operate, continue to send out reactive power and maintain stable voltage of the grid-connected point.
In summary, the embodiment suppresses the fault current of the direct current side when the MMC-UPFC series-connected side MMC fails in an alternating current mode, ensures that the parallel-connected side MMC can continuously send reactive power, maintains the voltage stability of the parallel-connected side power grid, and has important significance for stabilizing the power grid operation under the condition of the alternating current fault of the MMC-UPFC device in actual engineering.
The invention is not limited to the above embodiments, and all technical solutions formed by equivalent substitution fall within the scope of protection claimed by the invention.
Claims (7)
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105552950A (en) * | 2015-12-01 | 2016-05-04 | 山西大同大学 | Doubly-fed wind turbine generator hybrid fault ride-through method |
| CN109950916A (en) * | 2019-04-11 | 2019-06-28 | 华北电力大学 | UPFC Fault Transition Method Based on Hybrid Impedance |
| CN110086191A (en) * | 2019-01-31 | 2019-08-02 | 中国电力科学研究院有限公司 | A fault ride-through method for MMC-UPFC based on current-limiting reactor |
| CN111313407A (en) * | 2020-03-03 | 2020-06-19 | 华北电力大学 | UPFC fault transition device and method based on additional damping resistor |
| CN111371099A (en) * | 2020-03-03 | 2020-07-03 | 国家电网公司西北分部 | UPFC fault transition device and method based on thyristor transfer resistance circuit |
| US20210359588A1 (en) * | 2019-08-09 | 2021-11-18 | Toshiba Mitsubishi-Electric Industrial Systems Corporation | Power conversion device |
| CN114024294A (en) * | 2021-10-22 | 2022-02-08 | 武汉大学 | Virtual-physical integrated current limiting system and method suitable for half-bridge MMC |
-
2024
- 2024-02-26 CN CN202410207933.1A patent/CN118214067A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105552950A (en) * | 2015-12-01 | 2016-05-04 | 山西大同大学 | Doubly-fed wind turbine generator hybrid fault ride-through method |
| CN110086191A (en) * | 2019-01-31 | 2019-08-02 | 中国电力科学研究院有限公司 | A fault ride-through method for MMC-UPFC based on current-limiting reactor |
| CN109950916A (en) * | 2019-04-11 | 2019-06-28 | 华北电力大学 | UPFC Fault Transition Method Based on Hybrid Impedance |
| US20210359588A1 (en) * | 2019-08-09 | 2021-11-18 | Toshiba Mitsubishi-Electric Industrial Systems Corporation | Power conversion device |
| CN111313407A (en) * | 2020-03-03 | 2020-06-19 | 华北电力大学 | UPFC fault transition device and method based on additional damping resistor |
| CN111371099A (en) * | 2020-03-03 | 2020-07-03 | 国家电网公司西北分部 | UPFC fault transition device and method based on thyristor transfer resistance circuit |
| CN114024294A (en) * | 2021-10-22 | 2022-02-08 | 武汉大学 | Virtual-physical integrated current limiting system and method suitable for half-bridge MMC |
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