CN105634257B - A kind of MMC DC side fault current suppressing method based on virtual impedance - Google Patents
A kind of MMC DC side fault current suppressing method based on virtual impedance Download PDFInfo
- Publication number
- CN105634257B CN105634257B CN201510046240.XA CN201510046240A CN105634257B CN 105634257 B CN105634257 B CN 105634257B CN 201510046240 A CN201510046240 A CN 201510046240A CN 105634257 B CN105634257 B CN 105634257B
- Authority
- CN
- China
- Prior art keywords
- mmc
- virtual impedance
- bus
- voltage
- active power
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Abstract
The present invention relates to a kind of MMC DC side fault current suppressing method based on virtual impedance, belongs to transmission & distribution electro-technical field.The DC side failure of MMC can cause switching device overcurrent, the present invention is based on existing control strategies, by the way that the virtual impedance parallel circuit in primary system is mapped in controller by feedback function, equivalent increase DC bus impedance, the instantaneous rate of climb of fault current when to effectively MMC DC side be inhibited to break down, and the fault current rate of climb of other types failure will not be accelerated.Core of the invention technical solution is: firstly, real-time measurement MMC system dc busbar voltage, electric current and exchange side PCC point active power；Secondly, it is assumed that virtual impedance circuit is connected at DC bus, carries out DC voltage deviation by the virtual circuit to DC current and active power deviation calculates；It is modified finally, relevant drift correction amount is attached on the measured value of the active class control amount of DQ decoupling controller.
Description
Technical field
The invention belongs to transmission & distribution electro-technical field more particularly to a kind of MMC DC side fault currents based on virtual impedance
Suppressing method.
Background technique
Modularization multi-level converter (Modular Multilevel Converter, MMC) is transmitted with higher power
Capacity bears the advantages that voltage change ratio is low and harmonic characterisitic is preferable without a large amount of IGBT crimping series connection, device, is increasingly becoming
The development trend of flexible DC transmission.
The DC side failure of MMC can cause the substantially charge and discharge of sending end and receiving end inverter submodule, and then cause to switch
Device overcurrent.Compared with AC fault, the Evolution Rates after the DC side failure of MMC occurs are exceedingly fast, easily to remaining MMC that is connected
The normal operation of alternating current-direct current side have an impact, and cause switching device overcurrent in a very short period of time.It is opened under fault condition
The transient current size that device is flowed through before the device locking of pass directly affects the selection of switching device parameter.Pass through control mode reality
The inhibition of fault current, existing research almost do not relate to when now to MMC generation DC side failure.
Summary of the invention
Inhibit problem for the fault current for mentioning MMC generation DC side failure in above-mentioned background technique, the present invention uses
Virtual impedance control strategy is based on existing DQ decoupling control policy, right by increasing the feedback element of real power control amount in D axis
Ssystem transfer function is modified, and feedback control is mapped to formation virtual impedance parallel circuit, equivalent increase in primary system
DC bus impedance, the instantaneous rising of DC current and bridge arm current when so as to effectively inhibit MMC DC side to break down
Speed.
The present invention is mapping of the control system in primary system, itself will not generate shadow to the steady state operating condition of system
It rings；And when other failures such as system generation exchange side failure, additional control designed by the present invention will not accelerate its fault current
The rate of climb.The feature of technical solution of the present invention the following steps are included:
Step 1: utilizing current sensor real-time measurement MMC system dc bus current, surveyed in real time using voltage sensor
MMC system dc busbar voltage is measured, active power at power-measuring device measurement MMC system PCC point is utilized.Step 2: according to
Resistance value and reactance value in MMC circuit system parameter setting virtual impedance circuit, virtual resistance and virtual reactance are connected to system
Form be it is in parallel after connect at DC bus；DC voltage drift gage is carried out by virtual impedance parallel circuit to DC current
It calculates, carries out the calculating of active power deviation according to DC voltage deviation.Step 3: not according to the active class control amount of MMC controller
Together, relevant drift correction amount is attached on the measured value of the active class control amount of DQ decoupling controller and is modified, thus
Realize the real-time monitoring and inhibition to direct fault current.The present invention can be realized and be sent out in MMC system by three above step
The rate of climb of direct fault current (DC current, bridge arm current) is realized when raw DC side failure and is effectively inhibited.
Detailed description of the invention
Fig. 1 is the virtual impedance circuit diagram for being attached to DC bus；Fig. 2 is that DC voltage deviation and active power are inclined
Poor computing block diagram；Fig. 3 is the DQ decoupling controller for adding active class control amount deviation.
Specific embodiment
It below will be detailed to a kind of MMC DC side fault current suppressing method work based on virtual impedance of the present invention
Explanation.It is emphasized that following the description is only exemplary, the range and its application being not intended to be limiting of the invention.
The technical problems to be solved by the invention use virtual impedance control strategy, are based on existing DQ decoupling control policy,
By increasing the feedback element of real power control amount in D axis, ssystem transfer function is modified, feedback control is mapped to once
Virtual impedance parallel circuit, equivalent increase DC bus impedance, so as to effectively inhibit MMC DC side to occur are formed in system
The instantaneous rate of climb of DC current and bridge arm current when failure.The present invention adopts the following technical scheme that realization:
Step 1: utilizing current sensor real-time measurement MMC system dc bus current, be denoted asI dc, utilize voltage sensor
Real-time measurement MMC system dc busbar voltage is denoted asU dc, active power at MMC system PCC point is measured using power-measuring device,
It is denoted asP s.Step 2: according to the resistance value in MMC circuit system parameter setting virtual impedance circuitR virAnd reactance valueL vir,R vir
WithL virBe connected to system form be it is in parallel after connect at DC bus, as shown in Figure 1；To DC currentI dcBy virtual impedance
Parallel circuit carries out the calculating of DC voltage deviation, has:.WhereinsIt is defined as pull-type operator, according to direct current
It presses deviation to carry out the calculating of active power deviation, has:.Controller realizes that block diagram is as shown in Figure 2.Step 3: according to MMC
Relevant drift correction amount is attached to the active class control amount of DQ decoupling controller by the difference of the active class control amount of controller
It is modified on measured value, to realize the real-time monitoring and inhibition to direct fault current: if converter station is to determine DC voltage
Control station, then using step 2 calculate DC voltage deviation to dc voltage measurementsU dcIt is modified, controller outer ring
Value of feedback amendment are as follows:；If converter station be determine active power controller station, using step 2 calculating it is active
Power offset value is to wattful power messurement valueP sIt is modified, the amendment of controller outer loop feedback value are as follows:.Controller
It is as shown in Figure 3 to implement block diagram.It should be noted that step 1,2 and 3 is whole as summary of the invention, and three steps are organic
Indivisible entirety.
The foregoing is only a preferred embodiment of the present invention, but scope of protection of the present invention is not limited thereto,
In the technical scope disclosed by the present invention, any changes or substitutions that can be easily thought of by anyone skilled in the art,
It should be covered by the protection scope of the present invention.Therefore, protection scope of the present invention should be with scope of protection of the claims
Subject to.
Claims (1)
1. a kind of MMC DC side fault current suppressing method based on virtual impedance, it is characterized in that introducing at DC bus
Virtual impedance parallel circuit, comprising the following steps:
Step 1: utilizing current sensor real-time measurement MMC system dc bus current, be denoted asI dc, real-time using voltage sensor
Measurement MMC system dc busbar voltage is denoted asU dc, using active power at power-measuring device measurement MMC system PCC point, it is denoted asP s；
Step 2: according to the resistance value in MMC circuit system parameter setting virtual impedance parallel circuitR virAnd reactance valueL vir,R vir
WithL virSystem form is connected to connect after parallel connection at DC bus；
To DC bus currentI dcThe calculating of DC voltage deviation is carried out by virtual impedance parallel circuit, is had:
, whereinsFor pull-type operator；
The calculating of active power deviation is carried out according to DC voltage deviation, is had:
；
Step 3: according to the difference of the active class control amount of MMC controller, relevant drift correction amount being attached to DQ decoupling control
It is modified on the measured value of the active class control amount of device, to realize the real-time monitoring and inhibition to direct fault current:
If converter station is constant DC voltage control station, resulting DC voltage deviation is calculated to DC bus using step 2
Voltage measuring valueU dcIt is modified, the amendment of controller outer loop feedback value are as follows:
；
If converter station is to determine active power controller station, resulting active power deviation is calculated to active power using step 2
Measured valueP sIt is modified, the amendment of controller outer loop feedback value are as follows:
。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510046240.XA CN105634257B (en) | 2015-01-30 | 2015-01-30 | A kind of MMC DC side fault current suppressing method based on virtual impedance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510046240.XA CN105634257B (en) | 2015-01-30 | 2015-01-30 | A kind of MMC DC side fault current suppressing method based on virtual impedance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105634257A CN105634257A (en) | 2016-06-01 |
| CN105634257B true CN105634257B (en) | 2019-01-29 |
Family
ID=56048898
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510046240.XA Active CN105634257B (en) | 2015-01-30 | 2015-01-30 | A kind of MMC DC side fault current suppressing method based on virtual impedance |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105634257B (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106451634B (en) * | 2016-10-26 | 2019-03-22 | 徐州工业职业技术学院 | A kind of distributed storage battery group equalization charging/discharging thereof and distributed micro-grid structure |
| CN108258891B (en) * | 2016-12-28 | 2021-10-01 | 中国电力科学研究院 | Method and device for inhibiting resonance between end-to-end MMC-HVDC direct current side stations |
| CN107154641A (en) * | 2017-06-05 | 2017-09-12 | 湖南大学 | The stable control method of VSC HVDC transmission systems |
| CN107528495B (en) * | 2017-09-25 | 2019-11-08 | 中国电力科学研究院 | A kind of control method and system improving PWM inverter impact resistance |
| CN107895965A (en) * | 2017-10-18 | 2018-04-10 | 广东电网有限责任公司电力调度控制中心 | A kind of analysis method of grid-connected MMC ac input power characteristic |
| CN110311542B (en) * | 2019-07-09 | 2020-08-25 | 南方电网科学研究院有限责任公司 | Control method and control device for virtual reactance of modular multilevel converter |
| CN110829480A (en) * | 2019-11-07 | 2020-02-21 | 国网江苏省电力有限公司经济技术研究院 | Control strategy suitable for LCC-MMC hybrid cascade converter station parallel MMC unit |
| CN111224409A (en) * | 2020-01-17 | 2020-06-02 | 南方电网科学研究院有限责任公司 | Virtual impedance-based over-current suppression method for direct current access device |
| CN111130080A (en) * | 2020-01-17 | 2020-05-08 | 佛山科学技术学院 | Photovoltaic system instantaneous fault overcurrent suppression method based on virtual impedance |
| CN112152250B (en) * | 2020-09-21 | 2021-08-27 | 四川大学 | Flexible direct-current fault current combined limiting method considering bridge arm current suppression |
| CN112421682B (en) * | 2020-12-11 | 2021-07-09 | 南方电网科学研究院有限责任公司 | Multi-stage voltage correction control method and device for offshore alternating current fault |
| CN113067358A (en) * | 2021-03-25 | 2021-07-02 | 中国矿业大学 | Method for reducing direct current side current-limiting reactor of MMC type direct current network |
| CN113469454B (en) * | 2021-07-20 | 2023-04-07 | 华能陇东能源有限责任公司 | Integrated energy base direct current modulation parameter configuration method and system |
| CN114024294B (en) * | 2021-10-22 | 2023-08-15 | 武汉大学 | Virtual-physical integrated current limiting system and method suitable for half-bridge MMC |
| CN114362572B (en) * | 2022-01-13 | 2024-02-09 | 国网江苏省电力有限公司 | Calculation method for maximum temporary overvoltage of parallel MMC under alternating current short circuit fault |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103236702A (en) * | 2013-04-11 | 2013-08-07 | 合肥工业大学 | Microgrid reactive power balanced allocation method based on impedance composite control |
| CN103795080A (en) * | 2014-01-23 | 2014-05-14 | 湖南大学 | Grid connection method of MMC-type light direct-current power transmission system |
| CN104022665A (en) * | 2014-05-22 | 2014-09-03 | 清华大学 | Bridge arm instantaneous current direct control method of modular multilevel converter |
| CN104092239A (en) * | 2014-06-25 | 2014-10-08 | 国家电网公司 | Photovoltaic grid-connected control method based on modular multilevel converter |
| WO2014169388A1 (en) * | 2013-04-16 | 2014-10-23 | The Governing Council Of The University Of Toronto | Modular multilevel dc/dc converter for hvdc networks |
| CN104167760A (en) * | 2014-07-28 | 2014-11-26 | 湖南大学 | Modularization multi-level photovoltaic grid connected system and control method thereof |
-
2015
- 2015-01-30 CN CN201510046240.XA patent/CN105634257B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103236702A (en) * | 2013-04-11 | 2013-08-07 | 合肥工业大学 | Microgrid reactive power balanced allocation method based on impedance composite control |
| WO2014169388A1 (en) * | 2013-04-16 | 2014-10-23 | The Governing Council Of The University Of Toronto | Modular multilevel dc/dc converter for hvdc networks |
| CN103795080A (en) * | 2014-01-23 | 2014-05-14 | 湖南大学 | Grid connection method of MMC-type light direct-current power transmission system |
| CN104022665A (en) * | 2014-05-22 | 2014-09-03 | 清华大学 | Bridge arm instantaneous current direct control method of modular multilevel converter |
| CN104092239A (en) * | 2014-06-25 | 2014-10-08 | 国家电网公司 | Photovoltaic grid-connected control method based on modular multilevel converter |
| CN104167760A (en) * | 2014-07-28 | 2014-11-26 | 湖南大学 | Modularization multi-level photovoltaic grid connected system and control method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN105634257A (en) | 2016-06-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105634257B (en) | A kind of MMC DC side fault current suppressing method based on virtual impedance | |
| CN105634258B (en) | A kind of MMC exchange side fault current suppressing method based on virtual impedance | |
| CN107039993B (en) | Power band-turning control method for symmetrical bipolar flexible direct-current transmission converter | |
| WO2018176599A1 (en) | Mmc-based electromechanical transient simulation method and system for voltage source converter-based high voltage direct current and direct current power grid | |
| CN103501017B (en) | Microgrid stabilization controller | |
| KR102196898B1 (en) | Voltage and current control method and device of DC transmission system | |
| CN108599200A (en) | Urgent limit Poewr control method of the isolated island new energy through very bipolar soft straight power grid access | |
| JP6301973B2 (en) | Power loss correction method for high-voltage DC transmission system | |
| CN109038658A (en) | Off-lying sea wind-powered electricity generation flexible direct current transmitting system and land AC single phase ground fault traversing method | |
| CN105098825B (en) | Inverter and its operating method | |
| CN103543357A (en) | Method for prejudging phase change failure of converter valve | |
| CN105656072B (en) | A kind of LCC MMC types DC transmission system power coordination control method | |
| CN105634313B (en) | A kind of MMC loop current suppression control method based on virtual resistance | |
| CN110571840B (en) | Sending end fault ride-through control method and device for LCC-MMC power transmission system | |
| CN106130055A (en) | The lever variable-power control system of HVDC transmission system and method thereof | |
| CN108599220A (en) | It is a kind of to assess method and system of the synchronous capacitor to LCC-HVDC commutation failure inhibiting effect | |
| CN110311399A (en) | A kind of determination method and device of flexible direct current contribution current in the short | |
| CN106712068A (en) | Parallel hybrid DC power transmission system and reactive power regulation optimization method thereof | |
| CN105039998B (en) | A kind of control method of D.C. high voltage transmission earthing pole cathodic protection | |
| CN110058100A (en) | A kind of the Time delay measurement method, apparatus and system of DC transmission system | |
| US10254320B2 (en) | Method for measuring electric power value in an hvdc system | |
| KR101630511B1 (en) | Converter controller and operating method thereof | |
| CN105914773A (en) | Method for determining AC side power limit of current converter under asymmetrical alternating voltage | |
| CN206742860U (en) | The voltage coordinated control system of photovoltaic plant | |
| CN105634003A (en) | Virtual capacitance-based weak AC network MMC system control strategy |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |