CN108429278A - LCC-MMC system single valve group input control methods and DC transmission system - Google Patents
LCC-MMC system single valve group input control methods and DC transmission system Download PDFInfo
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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
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- 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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Abstract
The present invention provides LCC MMC system single valve group input control methods and DC transmission systems, by putting into LCC valve groups again after putting into MMC valve group, finally carry out the sequential setting of valve group DC voltage promotion, realize the orderly online input of the LCC MMC system single valve groups using height valve group tandem type, and the normal operation of remaining valve group is not influenced, there is good application value.Wherein MMC is put into straight-flow system first, if being because LCC is first put into, then in MMC starts charging process, LCC needs long-play in the state of close to zero DC voltage, its Trigger Angle is close to 90 degree at this time, AC system harmonic wave is big, very high to the reactive power support requirement of system, is highly detrimental to system run all right.And MMC harmonic characterisitics are good, without reactive power support requirement, even if longtime running under zero DC voltage state, will not have an impact AC system stability.
Description
Technical field
The invention belongs to electric system technical field of direct current power transmission, more particularly to LCC-MMC systems single valve group input control
Method and DC transmission system.
Background technology
Hybrid HVDC system combines Traditional DC transmission of electricity (LCC-HVDC) technology maturation, transmission line capability height, cost
Low and flexible DC power transmission (VSC-HVDC) control is flexible, active reactive independently decouples, without advantages such as commutation failures, becomes existing
Stage research hotspot.Wherein, modularization multi-level converter MMC is the long a kind of structure used in flexible DC transmission technology,
Modularization multi-level converter MMC uses sub-module cascade technology, and with expanding, performance is strong, harmonics level is low, switching loss is small
The advantages that, it is more suitable for matching the high-voltage large-capacity feature of LCC, constitutes Hybrid HVDC system.Sending end uses LCC transverters,
Receiving end is primarily adapted for use in receiving end using the LCC-MMC type Hybrid HVDC systems of MMC transverters a plurality of customary DC feed-in
System, the problems such as secondary commutation failure of customary DC can effectively improve by the introducing of MMC, improve system run all right
Property.
When straight-flow system is applied to extra-high voltage large capacity transmission occasion, LCC current conversion stations mostly use two double 12 pulsation valve groups
The topological structure of series operation, MMC are applied to extra-high voltage by limitations such as the resistance to voltage levels of switching device and Control System Design difficulty
When LCC-MMC type Hybrid HVDCs, it is also considered that use two concatenated structure types of valve group.It is flexible in order to increase system operation
Property and reliability, when the single valve groups of LCC or MMC need to exit because of maintenance or failure and other reasons, often through by equivalent locations
LCC valve groups and MMC valve group exit simultaneously so that remaining valve group continues to run with, to reduce straight-flow system power loss.And work as valve
Group maintenance finish or fault clearance after also need that valve group will be had dropped out and put into online, restore straight-flow system total head operating status.For this purpose,
In extra-high voltage direct-current engineering, the online input control of single valve group becomes important one of controlling unit, and is put into single valve group
In the process, it is desirable that the normal operation of remaining valve group is not had an impact.
Currently, the research about extra-high voltage flexible direct current and extra-high voltage Hybrid HVDC technology is still in initial stage,
Research in terms of in relation to flexible direct current converter station single valve group online input is rarely reported.Although the list of conventional extra-high voltage direct-current system
Valve group puts into the existing research of technology online, but because of the difference on LCC transverters and MMC converter Control characteristics, it is necessary to simultaneously
In conjunction with MMC controls flexibly, harmonic characterisitic the features such as that advantages and LCC subnormal voltage operation time-harmonic waves are big, reactive requirement is high such as good,
The single valve group that more rational and orderly is formulated for LCC-MMC mixed DC systems puts into scheme online.
Invention content
The purpose of the present invention is to provide LCC-MMC system single valve group input control methods and DC transmission systems, are used for
Solve the problems, such as that the single valve group of LCC-MMC Hybrid HVDC systems is put into online.
To achieve the above object, the present invention provides a kind of LCC-MMC systems single valve group input control method, including it is following
Technical solution：
Method scheme one, a kind of LCC-MMC systems single valve group input control method, including sending end current conversion station, the receiving end change of current
It stands, the sending end current conversion station includes at least two LCC valve groups, and the receiving end current conversion station includes at least two MMC valve groups, wherein one
A LCC valve groups constitute one group of valve group with a MMC valve group, when needing to put into valve group, control MMC valve group input to be put into,
After the completion of MMC valve group is put into, LCC valve groups input corresponding with MMC valve group to be put into is controlled, after the completion of LCC valve groups are put into,
The DC voltage command value of control MMC valve group rises to rated value.
Method scheme two, on the basis of method scheme one, when the valve group for needing to put into is at least two groups valve group, control
After the completion of one of which valve group input, controls remaining valve group and put into successively.
Method scheme three, on the basis of method scheme two, the input process of MMC valve group is：It charges, fills to MMC valve group
Unlock carries out constant DC current control after the completion of electric, and DC current instruction is given as zero, when MMC valve group DC current is instructed from zero
When rising to as DC line electric current, constant DC current control is converted into constant DC voltage control, DC voltage instruction
It is given as zero.
Method scheme four, on the basis of method scheme two, the input process of LCC valve groups is：Using Trigger Angle by LCC valves
Group unlocks and carries out constant DC current control, and DC current instruction is given as zero, when LCC valve group DC currents are instructed from liter above freezing
When to as DC line electric current, constant DC current control, DC current instruction is still used to be given as direct current LCC valve groups
The electric current of circuit.
Method scheme five, on the basis of method scheme three, each MMC valve group be each configured with the corresponding valve group input of control or
First direct current field switch of excision, the positive port of DC side of each MMC valve group are connected with the positive end of incoming cables of corresponding direct current field switch,
The positive DC side end mouth of each MMC valve group is connected with the negative end of incoming cables of corresponding direct current field switch；The first direct current field switch packet
Include the first by-pass knife switch, the first by-pass switch, the first isolation switch and the second isolation switch, one end of the first by-pass knife switch and the
One end of one isolation switch, which is connected, constitutes the positive leading-out terminal of the first direct current field switch, the other end of the first by-pass knife switch and second every
It is connected from one end of disconnecting link and constitutes the negative leading-out terminal of the first direct current field switch, one end of the first by-pass switch and the first isolation switch
The other end be connected and constitute the positive end of incoming cables of the first direct current field switch, the other end of the first by-pass switch and the second isolation switch
The other end, which is connected, constitutes the negative end of incoming cables of the first direct current field switch；To MMC valve group using after constant DC current control, MMC is controlled
Valve group is in the state that partly puts into operation, and the partly state of putting into operation refers to that the first by-pass knife switch disconnects, the first by-pass switch,
First isolation switch and the second isolation switch are closed；When the instruction of MMC valve group DC current rises to the electric current of DC line, control
MMC valve group processed is in input state, and the input state refers to the first by-pass knife switch, the first by-pass switch disconnects, the first isolation knife
Lock and the second isolation switch are closed.
Method scheme six, on the basis of method scheme four, each LCC valve groups be each configured with the corresponding valve group input of control or
Second direct current field switch of excision, the positive port of DC side of each LCC valve groups are connected with the positive end of incoming cables of corresponding direct current field switch,
The positive DC side end mouth of each LCC valve groups is connected with the negative end of incoming cables of corresponding direct current field switch；The second direct current field switch packet
Include the second by-pass knife switch, the second by-pass switch, third isolation switch and the 4th isolation switch, one end of the second by-pass knife switch and the
One end of three isolation switch, which is connected, constitutes the positive leading-out terminal of the second direct current field switch, the other end of the second by-pass knife switch and the 4th every
It is connected from one end of disconnecting link and constitutes the negative leading-out terminal of the second direct current field switch, one end and the third isolation switch of the second by-pass switch
The other end be connected and constitute the positive end of incoming cables of the second direct current field switch, the other end of the second by-pass switch and the 4th isolation switch
The other end, which is connected, constitutes the negative end of incoming cables of the second direct current field switch；To LCC valve groups using before constant DC current control, LCC is controlled
Valve group is in the state that partly puts into operation, and the partly state of putting into operation refers to that the second by-pass knife switch disconnects, the second by-pass switch,
Third isolation switch and the 4th isolation switch are closed；After the instruction of LCC valve group DC currents rises to the electric current of DC line, control
LCC valve groups processed are in input state, and the input state refers to the second by-pass knife switch, the second by-pass switch disconnects, third isolation knife
Lock and the 4th isolation switch are closed.
The present invention also provides a kind of DC transmission systems, including following technical scheme：
System schema one, a kind of DC transmission system, including sending end current conversion station, receiving end current conversion station and controller, it is described to send
It includes at least two LCC valve groups to hold current conversion station, and the receiving end current conversion station includes at least two MMC valve groups, one of LCC valve groups
One group of valve group is constituted with a MMC valve group, when needing to put into valve group, the controller is for controlling MMC valve group to be put into
Input controls LCC valve groups input corresponding with MMC valve group to be put into after the completion of MMC valve group is put into, and LCC valve groups have been put into
The DC voltage command value of Cheng Hou, control MMC valve group rise to rated value.
System schema two, on the basis of system schema one, when the valve group for needing to put into is at least two groups valve group, control
After the completion of one of which valve group input, controls remaining valve group and put into successively.
System schema three, on the basis of system schema two, the input process of MMC valve group is：It charges, fills to MMC valve group
Unlock carries out constant DC current control after the completion of electric, and DC current instruction is given as zero, when MMC valve group DC current is instructed from zero
When rising to as DC line electric current, constant DC current control is converted into constant DC voltage control, DC voltage instruction
It is given as zero.
System schema four, on the basis of system schema two, the input process of LCC valve groups is：Using Trigger Angle by LCC valves
Group unlocks and carries out constant DC current control, and DC current instruction is given as zero, when LCC valve group DC currents are instructed from liter above freezing
When to as DC line electric current, constant DC current control, DC current instruction is still used to be given as direct current LCC valve groups
The electric current of circuit.
System schema five, on the basis of system schema three, each MMC valve group be each configured with the corresponding valve group input of control or
First direct current field switch of excision, the positive port of DC side of each MMC valve group are connected with the positive end of incoming cables of corresponding direct current field switch,
The positive DC side end mouth of each MMC valve group is connected with the negative end of incoming cables of corresponding direct current field switch；The first direct current field switch packet
Include the first by-pass knife switch, the first by-pass switch, the first isolation switch and the second isolation switch, one end of the first by-pass knife switch and the
One end of one isolation switch, which is connected, constitutes the positive leading-out terminal of the first direct current field switch, the other end of the first by-pass knife switch and second every
It is connected from one end of disconnecting link and constitutes the negative leading-out terminal of the first direct current field switch, one end of the first by-pass switch and the first isolation switch
The other end be connected and constitute the positive end of incoming cables of the first direct current field switch, the other end of the first by-pass switch and the second isolation switch
The other end, which is connected, constitutes the negative end of incoming cables of the first direct current field switch；To MMC valve group using after constant DC current control, MMC is controlled
Valve group is in the state that partly puts into operation, and the partly state of putting into operation refers to that the first by-pass knife switch disconnects, the first by-pass switch,
First isolation switch and the second isolation switch are closed；When the instruction of MMC valve group DC current rises to the electric current of DC line, control
MMC valve group processed is in input state, and the input state refers to the first by-pass knife switch, the first by-pass switch disconnects, the first isolation knife
Lock and the second isolation switch are closed.
System schema six, on the basis of system schema four, each LCC valve groups be each configured with the corresponding valve group input of control or
Second direct current field switch of excision, the positive port of DC side of each LCC valve groups are connected with the positive end of incoming cables of corresponding direct current field switch,
The positive DC side end mouth of each LCC valve groups is connected with the negative end of incoming cables of corresponding direct current field switch；The second direct current field switch packet
Include the second by-pass knife switch, the second by-pass switch, third isolation switch and the 4th isolation switch, one end of the second by-pass knife switch and the
One end of three isolation switch, which is connected, constitutes the positive leading-out terminal of the second direct current field switch, the other end of the second by-pass knife switch and the 4th every
It is connected from one end of disconnecting link and constitutes the negative leading-out terminal of the second direct current field switch, one end and the third isolation switch of the second by-pass switch
The other end be connected and constitute the positive end of incoming cables of the second direct current field switch, the other end of the second by-pass switch and the 4th isolation switch
The other end, which is connected, constitutes the negative end of incoming cables of the second direct current field switch；To LCC valve groups using before constant DC current control, LCC is controlled
Valve group is in the state that partly puts into operation, and the partly state of putting into operation refers to that the second by-pass knife switch disconnects, the second by-pass switch,
Third isolation switch and the 4th isolation switch are closed；After the instruction of LCC valve group DC currents rises to the electric current of DC line, control
LCC valve groups processed are in input state, and the input state refers to the second by-pass knife switch, the second by-pass switch disconnects, third isolation knife
Lock and the 4th isolation switch are closed.
The beneficial effects of the invention are as follows：
The DC transmission system of LCC-MMC mixing provided by the invention, it is contemplated that LCC transverters and MMC converter Controls
Difference in characteristic, combines the advantages such as MMC controls are flexible, harmonic characterisitic is good and LCC subnormal voltage operation time-harmonic waves are big, idle
The features such as demand is high, by putting into LCC valve groups again after putting into MMC valve group, the sequential for finally carrying out valve group DC voltage promotion is set
It sets, realizes the orderly online input of the LCC-MMC system single valve groups using height valve group tandem type, and do not influence remaining valve
The normal operation of group has good application value.Wherein MMC is put into straight-flow system first, if being because by LCC elder generations
Input, then in MMC starts charging process, LCC needs long-play in the state of close to zero DC voltage, it is touched at this time
Nearly 90 degree of corner connection is sent out, AC system harmonic wave is big, very high to the reactive power support requirement of system, is highly detrimental to system run all right
Property.And MMC harmonic characterisitics are good, without reactive power support requirement, even if longtime running under zero DC voltage state, will not to hand over
Streaming system stability has an impact.
Description of the drawings
Fig. 1 is the LCC-MMC monopolar DC system schematic diagrames of two valve group tandem types；
Fig. 2 is the online input control method flow diagram of single valve group of the present invention.
Specific implementation mode
The specific implementation mode of the present invention is further described below in conjunction with the accompanying drawings：
A kind of DC transmission system of LCC-MMC mixing, including sending end power grid, sending end current conversion station, receiving end current conversion station, receiving end
The exchange side of power grid and controller, sending end current conversion station is connect with sending end power grid, and exchange side and the receiving end power grid of receiving end current conversion station connect
It connects, sending end current conversion station includes at least two LCC valve groups, and receiving end current conversion station includes at least two MMC valve groups, the sending end current conversion station
Including at least two LCC valve groups, the DC side cascade Connection of each LCC valve groups, each LCC valve groups are each configured with the corresponding valve group of control
Input or the second direct current field switch of excision, the positive inlet wire of the positive port of DC side and corresponding direct current field switch of each LCC valve groups
End connection, the positive DC side end mouth of each LCC valve groups are connected with the negative end of incoming cables of corresponding direct current field switch；The receiving end current conversion station
Including at least two MMC valve groups, each MMC valve group is each configured with the corresponding valve group input of control or the first DC fields of excision are opened
It closes, the positive port of DC side of each MMC valve group is connected with the positive end of incoming cables of corresponding direct current field switch, the DC side of each MMC valve group
Negative terminal mouth is connected with the negative end of incoming cables of corresponding direct current field switch；The positive leading-out terminal of first LCC valve group by DC line with
The positive leading-out terminal connection of first MMC valve group.One of LCC valve groups constitute one group of valve group with MMC valve group, when needing to throw
When entering valve group, the controller is used to control MMC valve group input to be put into, and after the completion of MMC valve group is put into, controls and wait to throw
The corresponding LCC valve groups input of MMC valve group entered, after the completion of LCC valve groups are put into, in the DC voltage command value of control MMC valve group
Rise to rated value.
In the present embodiment, when the valve group for needing to put into is at least two groups valve group, control one of which valve group input is completed
Afterwards, remaining valve group is controlled to put into successively.
Specifically, by taking the LCC-MMC monopolar DC systems of two valve group tandem types of a use shown in FIG. 1 as an example.It send
End is LCC current conversion stations, and receiving end is MMC current conversion stations.Each end is connected in series with by two valve groups constitutes height valve group topology pattern,
Middle LCC1, LCC2 are respectively the ends LCC high and low pressure valve group, and MMC1, MMC2 are respectively the ends MMC high and low pressure valve group, LCC1 valve groups
Exchange side is connect by the first transformer with sending end power grid, and the exchange side of LCC2 valve groups is connected by the second transformer and sending end power grid
It connects, the exchange side of MMC1 valve groups is connect by third transformer with receiving end power grid, and the exchange side of MMC2 valve groups passes through the 4th transformation
Device is connect with receiving end power grid.
Each valve group DC side contains a set of direct current field switch, for putting into or cutting off the valve group.The of MMC1 valve groups
One DC fields switch include the first by-pass knife switch BPI1, the first high speed by-pass switch BPS1 and the first isolation switch Q1, second every
From disconnecting link Q2.Wherein, one end of BPI1 is connected with one end of Q1, and as the positive leading-out terminal of the first direct current field switch, BPI1's
The other end is connected with one end of Q2, and as the negative leading-out terminal of the first direct current field switch, one end of BPS1 and the other end phase of Q1
Even, and as the positive end of incoming cables of the first direct current field switch, the other end of BPS1 is connected with the other end of Q2, and as the first direct current
The negative end of incoming cables of field switch.Second direct current field switch of LCC1 valve groups includes the second by-pass knife switch BPI2, and the first high speed bypass is opened
Close BPS2 and the first isolation switch Q3, the second isolation switch Q4.Wherein, one end of BPI2 is connected with one end of Q3, and as
The positive leading-out terminal of two direct current field switches, the other end of BPI2 are connected with one end of Q4, and as the second direct current field switch it is negative go out
Line end, one end of BPS2 are connected with the other end of Q3, and as the positive end of incoming cables of the second direct current field switch, the other end of BPS2 with
The other end of Q4 is connected, and as the negative end of incoming cables of the second direct current field switch.Similarly, the corresponding direct current field switch of other valve groups with
The structure of the direct current field switch of MMC1 and LCC1 is the same, is repeated no more herein.
The positive and negative port of direct current of LCC1, LCC2, MMC1 and MMC2 respectively with the positive and negative end of incoming cables phase of its direct current field switch
Even.The negative leading-out terminal of LCC1 direct current field switches is connected with the positive leading-out terminal of LCC2 direct current field switches, and LCC1 direct currents field switch is just
Leading-out terminal is connected with DC line electrode line, the negative leading-out terminal ground connection of LCC2 direct current field switches.The direct current field switch of MMC valve group goes out
The connection method of line end is similar with the connection method of the long switch wire outlet terminal of the direct current of LCC valve groups.
One group of valve group is constituted with LCC1 and MMC1, when LCC2 and MMC2 constitute another group of valve group, the maintenance of MMC1 valve groups finishes
Need to illustrate for the operating mode put into again (can also be that LCC1 and MMC2, LCC2 and MMC1 respectively constitute one group of valve group,
Input strategy is consistent).Before MMC1 inputs, hybrid system will partly press operation by two valve groups of LCC2, MMC2, LCC1, MMC1's
Direct current field switch is in the state of exiting；The direct current field switch of LCC2, MMC2 are in input state.
Fig. 2 gives the flow chart of the online input control scheme of each end valve group to be put into.At each end, valve group to be put into is straight
Flow field switch first puts into MMC valve groups to be put into when exiting state, later again puts into LCC valve groups to be put into, finally
Valve group DC voltage is promoted again.In the present embodiment, for MMC1 valve groups, it refers to that BPI1 is closed that direct current field switch, which is in and exits state,
It closes, BPS1, Q1, Q2 are disconnected；It refers to that BPI1 is disconnected that the direct current field switch, which is in half input state, and BPS1, Q1, Q2 are closed
It closes；It refers to that BPI1, BPS1 are disconnected that the direct current field switch, which is in input state, and Q1, Q2 are closed.Wherein, turned by exiting state
Each switching operation is when putting into state for half：It is closed Q1, Q2 first, recloses BPS1, disconnects BPI1 later.
At each end, the direct current field switch of valve group to be put into is in state out of service, at the direct current field switch of remaining valve group
The process of the valve group to be put into each end control includes the following steps when the state of input, is with MMC1 valve groups and LCC1 valve groups
Example：
A, start MMC1 and carry out submodule capacitor charging, unlocked after charging complete, carry out constant DC current control, direct current
It is zero that stream instruction, which is given,；
B, it is closed Q1, Q2 of MMC1 successively, recloses BPS1, disconnects BPI1 later, the direct current field switch of MMC1 is made to switch to
Half input state；
C, the instruction of MMC1 DC currents is gradually raised to current DC line levels of current from zero, at this time on the BPS1 of MMC1
The electric current flowed through will be continuously decreased up to being zero, and BPS1 is made to have turn-off criterion；
D, the BPS1 for disconnecting MMC1 makes the direct current field switch of MMC1 switch to input state, and MMC1 switchs to determine direct current voltage-controlled
System, DC voltage are instructed to being zero, to maintain the original working voltage of straight-flow system, levels of current；
E, it is closed Q3, Q4 of LCC1 successively, recloses BPS2, disconnects BPI2 later, the direct current field switch of LCC1 is made to switch to
Half input state；
F, it unlocks LCC1 with 90 degree of Trigger Angles and uses constant DC current control, DC current instruction is gradually promoted to from zero
Current DC line levels of current, the electric current flowed through on the BPS2 of LCC1 at this time will be continuously decreased up to being zero, and BPS2 is made to have
Turn-off criterion；
G, the BPS2 for disconnecting LCC1, makes the direct current field switch of LCC1 switch to input state, and direct current flow control is determined in LCC1 holdings
Make constant, DC current is instructed to for the levels of current on current DC line, with maintain the original working voltage of straight-flow system,
Levels of current；
H, by operating above, LCC1 and MMC1 may be implemented the online input of unperturbed, but working voltage both at this time
It is zero with power, it is also necessary to which being lifted voltage makes straight-flow system restore total head operation, improves transmission line capability.For this purpose, last MMC1
Valve group should gradually promote DC voltage command value to rated value.Ends LCC1 must under the effect of constant DC current control device during this
The voltage that the Trigger Angle that LCC1 can so be turned down makes its DC voltage follow MMC1 is lifted, then the power of LCC1 and MMC1 also will be with
The raising of voltage and gradually increase.
So far, input finishes LCC1 and MMC1 online, and DC voltage and power are restored to normal level.
Why MMC1 is put into straight-flow system first, if being filled in MMC1 startups because first putting into LCC1
In electric process, LCC1 needs long-play in the state of close to zero DC voltage, its Trigger Angle is close to 90 degree at this time, exchange
System harmonics are big, very high to the reactive power support requirement of system, are highly detrimental to system run all right.And MMC harmonic characterisitics are good,
There is no reactive power support requirement, even if longtime running under zero DC voltage state, will not generate shadow to AC system stability
It rings.
Specific embodiment is presented above, but the present invention is not limited to embodiment described above.The present invention
Basic ideas be above-mentioned basic scheme, for those of ordinary skill in the art, introduction according to the present invention is designed each
The model of kind deformation, formula, parameter do not need to spend creative work.The case where not departing from the principle and spirit of the invention
Under to embodiment carry out variation, modification, replacement and deformation still fall in protection scope of the present invention.
Claims (10)
1. a kind of LCC-MMC systems single valve group input control method, which is characterized in that including sending end current conversion station, receiving end current conversion station,
The sending end current conversion station includes at least two LCC valve groups, and the receiving end current conversion station includes at least two MMC valve groups, one of them
LCC valve groups constitute one group of valve group with a MMC valve group, when needing to put into valve group, control MMC valve group input to be put into,
After the completion of MMC valve group input, LCC valve groups input corresponding with MMC valve group to be put into, after the completion of LCC valve groups are put into, control are controlled
The DC voltage command value of MMC valve group processed rises to rated value.
2. LCC-MMC systems single valve group input control method according to claim 1, which is characterized in that when needing to put into
Valve group be at least two groups valve group when, control one of which valve group input after the completion of, control remaining valve group and put into successively.
3. LCC-MMC systems single valve group input control method according to claim 2, which is characterized in that the throwing of MMC valve group
Entering process is：It charges to MMC valve group, unlock progress constant DC current control after charging complete, DC current instruction is given as zero,
When MMC valve group DC current is instructed from above freezing rise to as DC line electric current, it is fixed that constant DC current control is converted to
DC voltage control, DC voltage instruction are given as zero.
4. LCC-MMC systems single valve group input control method according to claim 2, which is characterized in that the throwing of LCC valve groups
Entering process is：LCC valve groups are unlocked to using Trigger Angle and are carried out constant DC current control, DC current instruction is given as zero, when
The instruction of LCC valve group DC currents from it is above freezing rise to as DC line electric current when, to LCC valve groups still using determining DC current
Control, DC current instruct the electric current for being given as DC line.
5. LCC-MMC systems single valve group input control method according to claim 3, which is characterized in that each MMC valve component
Pei Zhiyou not control the first direct current field switch of corresponding valve group input or excision, the positive port of DC side of each MMC valve group with it is corresponding
Direct current field switch positive end of incoming cables connection, the negative inlet wire of the positive DC side end mouth of each MMC valve group and corresponding direct current field switch
End connection；The first direct current field switch includes the first by-pass knife switch, the first by-pass switch, the first isolation switch and the second isolation
Disconnecting link, one end of the first by-pass knife switch is connected with one end of the first isolation switch constitutes the positive leading-out terminal of the first direct current field switch,
The other end of first by-pass knife switch is connected with one end of the second isolation switch constitutes the negative leading-out terminal of the first direct current field switch, and first
One end of by-pass switch is connected with the other end of the first isolation switch constitutes the positive end of incoming cables of the first direct current field switch, the first bypass
The other end of switch is connected with the other end of the second isolation switch constitutes the negative end of incoming cables of the first direct current field switch；To MMC valve group
After constant DC current control, control MMC valve group, which is in, partly to put into operation state, and the partly state of putting into operation refers to the
One by-pass knife switch disconnects, and the first by-pass switch, the first isolation switch and the second isolation switch are closed；When MMC valve group DC current
When instruction rises to the electric current of DC line, control MMC valve group is in input state, and the input state refers to the first bypass knife
Lock, the first by-pass switch disconnect, and the first isolation switch and the second isolation switch are closed.
6. LCC-MMC systems single valve group input control method according to claim 4, which is characterized in that each LCC valve groups point
Pei Zhiyou not control the second direct current field switch of corresponding valve group input or excision, the positive port of DC side of each LCC valve groups with it is corresponding
Direct current field switch positive end of incoming cables connection, the negative inlet wire of the positive DC side end mouth of each LCC valve groups and corresponding direct current field switch
End connection；The second direct current field switch includes the second by-pass knife switch, the second by-pass switch, third isolation switch and the 4th isolation
Disconnecting link, one end of the second by-pass knife switch is connected with one end of third isolation switch constitutes the positive leading-out terminal of the second direct current field switch,
The other end of second by-pass knife switch is connected with one end of the 4th isolation switch constitutes the negative leading-out terminal of the second direct current field switch, and second
One end of by-pass switch is connected with the other end of third isolation switch constitutes the positive end of incoming cables of the second direct current field switch, the second bypass
The other end of switch is connected with the other end of the 4th isolation switch constitutes the negative end of incoming cables of the second direct current field switch；To LCC valve groups
Before constant DC current control, control LCC valve groups, which are in, partly to put into operation state, and the partly state of putting into operation refers to the
Two by-pass knife switches disconnect, and the second by-pass switch, third isolation switch and the 4th isolation switch are closed；When LCC valve group DC currents
After instruction rises to the electric current of DC line, control LCC valve groups are in input state, and the input state refers to the second bypass knife
Lock, the second by-pass switch disconnect, and third isolation switch and the 4th isolation switch are closed.
7. a kind of DC transmission system, which is characterized in that including sending end current conversion station, receiving end current conversion station and controller, the sending end
Current conversion station include at least two LCC valve groups, the receiving end current conversion station include at least two MMC valve groups, one of LCC valve groups with
One MMC valve group constitutes one group of valve group, and when needing to put into valve group, the controller is used to control MMC valve group to be put into and throws
Enter, after the completion of MMC valve group is put into, controls LCC valve groups input corresponding with MMC valve group to be put into, LCC valve groups input is completed
Afterwards, the DC voltage command value of control MMC valve group rises to rated value.
8. DC transmission system according to claim 7, which is characterized in that when the valve group for needing to put into is at least two groups valve
When group, after the completion of control one of which valve group input, controls remaining valve group and put into successively.
9. DC transmission system according to claim 8, which is characterized in that the input process of MMC valve group is：To MMC valve
Group charging, unlock progress constant DC current control after charging complete, DC current instruction is given as zero, when MMC valve group direct current
Stream instruction from it is above freezing rise to as DC line electric current when, constant DC current control is converted into constant DC voltage control, directly
Stream voltage instruction is given as zero.
10. DC transmission system according to claim 8, which is characterized in that the input process of LCC valve groups is：Using tactile
LCC valve groups are unlocked and are carried out constant DC current control by hair angle, and DC current instruction is given as zero, when LCC valve group DC currents
Instruction from it is above freezing rise to as DC line electric current when, constant DC current control is still used to LCC valve groups, DC current refers to
Enable the electric current for being given as DC line.
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| CN108429278B (en) | 2020-08-25 |
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