CN104934948B - The DC Line Fault sweep-out method of Boost DC auto-transformer - Google Patents
The DC Line Fault sweep-out method of Boost DC auto-transformer Download PDFInfo
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Abstract
The present invention provides a kind of DC Line Fault sweep-out methods of Boost DC auto-transformer, the direct current auto-transformer includes voltage source converter (11), line commutation current transformer (12) and converter power transformer (13), the DC side of the voltage source converter is connected between low-voltage direct circuit and the neutral conductor or ground wire, the DC side of the line commutation current transformer is connected between hvdc transmission line and low-voltage direct circuit, the low-voltage direct circuit, the low-voltage direct-current end of the line commutation current transformer and the high-voltage direct-current end of the voltage source converter link together, the exchange side of the line commutation current transformer and the exchange side of the voltage source converter are linked together by the converter power transformer；When detecting DC Line Fault, the line commutation current transformer is converted into inverter pattern by rectifier pattern.By method proposed by the present invention, voltage boosting dc auto-transformer can be used for removing short trouble, realize the function of dc circuit breaker.
Description
Technical field
The present invention relates to high voltage direct current (HVDC) field of power transmission, and in particular to a kind of direct current transmission using commutator transformer
Line fault sweep-out method.
Background technology
With Chinese national economy and the high speed development of power grid construction, technology of transmission of electricity is faced with unprecedented development situation.By
Have the characteristics that power transmission distance is remote, power transmission capacity is big, control is flexible in direct current transportation, in one, 20 year future, high-voltage dc transmission
Electricity will play the role of highly important in long-distance and large-capacity power transmission and two aspect of national network in China's power grid construction.
Based on the demand that transmission line of electricity voltage is raised and lowered, commutator transformer will be as in following high-voltage direct current
A kind of basic component.For example, the direct-current transmission voltage of high altitude localities DC power transmission line is relatively low, low altitude area direct current is defeated
The direct-current transmission voltage of electric line is higher, and Boost DC transformer can be applied in the field for using one direction power transmission
It closes, the relatively low direct-current transmission voltage from high altitude localities DC power transmission line can be increased in low altitude area higher
Voltage class (such as from 400kV to 800kV) is simultaneously connected to another DC power transmission line.
Commutator transformer does not obtain practical practicality also in high-voltage direct current at present.The previous invention of applicant
In, it is proposed that the topological structure of Boost DC auto-transformer.One of which topological structure is mixed type direct current self coupling transformation
Device, as shown in Figure 1.Mixed type direct current auto-transformer is made of 3 parts：Voltage source converter VSC11, line commutation current transformer
LCC12 and converter power transformer 13.The exchange side of VSC and LCC is linked together by converter power transformer 13.VSC inverters 11
DC side is connected between low-voltage direct circuit and the neutral conductor (or ground wire)；The DC side of LCC rectifiers 12 is connected to high straightening
Between Flow Line and low-voltage direct circuit；Low-voltage direct circuit, the low-voltage direct-current end of LCC rectifiers 12 and VSC inverters 11
High-voltage direct-current end link together；The exchange side of LCC rectifiers 12 and the exchange side of VSC inverters 11 pass through interstage exchange
Transformer 13 links together.
Due to there is no electrical isolation between the low pressure side and high pressure side of direct current auto-transformer, when direct-current short circuit failure occurs
When, there is an urgent need for a kind of schemes can remove short circuit current and isolated fault circuit.Up to the present, do not find that this field is ground also
Study carefully personnel this problem is studied and discussed.
Usually, the direct current auto-transformer being made of two routine VSC transverters cannot eliminate High Level DC Voltage side hair
Raw direct-current short circuit electric current, this is because short circuit current will be connected by the anti-paralleled diode of switching device in VSC.However,
For mixed type voltage boosting dc auto-transformer as shown in Figure 1, the line commutation transverter LCC therein based on thyristor is carried
It has supplied to realize the possibility that DC Line Fault is removed.For being happened at the DC Line Fault of DC low-voltage side, because in LCC current transformers
Thyristor will block the current path of the exchange side of VSC and the DC current path of high voltage transmission line trackside, mixed type direct current self coupling
Transformer does not provide short circuit current.However for being happened at the DC Line Fault of high voltage transmission line trackside, it is still desirable to which it is special to design
Control method realizes the removing of DC Line Fault.
Therefore, a kind of control method how is designed to realize the removing of high voltage transmission line trackside DC Line Fault, so as to improve height
The reliability of straightening convertor transformer is the technical issues of those skilled in the art is urgently to be resolved hurrily.
Invention content
The present invention provides a kind of DC Line Fault sweep-out methods of Boost DC auto-transformer, can pass through transformer
It removes and short trouble is isolated, so as to improve the reliability of commutator transformer.
To achieve the above object, the present invention provides following technical solution：
A kind of DC Line Fault sweep-out method of Boost DC auto-transformer, the direct current auto-transformer include voltage
Source current transformer (VSC), line commutation current transformer (LCC) and converter power transformer, the DC side of the voltage source converter are connected to
Between low-voltage direct circuit and the neutral conductor or ground wire, the DC side of the line commutation current transformer be connected to hvdc transmission line and
Between low-voltage direct circuit, the low-voltage direct circuit, the low-voltage direct-current end of the line commutation current transformer and the voltage
The high-voltage direct-current end of source current transformer links together, the exchange side of the line commutation current transformer and the voltage source converter
Exchange side linked together by the converter power transformer；When detecting DC Line Fault, by the line commutation current transformer
Inverter pattern is converted to by rectifier pattern.
Preferably, by the Trigger Angle phase shift of the line commutation current transformer to more than 90 degree.
Preferably, the voltage source converter is converted to rectifier pattern by inverter pattern.
Preferably, the modulation degree of the voltage source converter is increased.
Preferably, the modulation degree of the voltage source converter is increased into maximum value.
Preferably, the phase alternating current is made to level off to reduction in the introducing of each phase of the voltage source converter exchange side
Voltage.
Preferably, by controlling the turn-on and turn-off of each insulated gate bipolar transistor (IGBT) valve group, make to introduce
The phase alternating current levels off to the voltage of reduction.
The ac-side current of the voltage source converter is preferably based on, to control the conducting of each IGBT valve groups
And shutdown.
Preferably, the voltage source converter is by multiple low-pressure sides being connected between low-voltage direct terminal and ac terminal
IGBT valve groups and multiple neutral line side IGBT valve groups compositions being connected between neutral line terminal and ac terminal；Detection is flowed through respectively
The current direction of each phase of the exchange side of the voltage source converter, and proceeded as follows according to current direction：If inspection
It measures a certain phase current and flows to the converter power transformer from the voltage source converter ac terminal, then will connect described in the phase
The IGBT valve groups shutdown of low-voltage direct side, while the neutrality line side IGBT valve groups for connecting the phase are connected；If detect certain
One phase current flows to the voltage source converter ac terminal from the converter power transformer, then the low-pressure direct that will connect the phase
The conducting of side IGBT valve groups is flowed, and the neutrality line side IGBT valve groups for connecting the phase are turned off.
Preferably, the voltage source converter is two level voltage source current transformer of three-phase semi-bridge type, two electricity of three phase full bridge type
Level voltage source current transformer or three-level voltage source current transformer.
Preferably, the voltage source converter is semi-bridge type modular multilevel voltage source converter；The half-bridge pattern
Block multi-level voltage source current transformer is by multiple low-pressure side submodules being connected between low-voltage direct terminal and ac terminal and more
A neutral line side submodule composition being connected between neutral line terminal and ac terminal；The submodule is by capacitor, one
A series IGBT connected with the capacitor and a parallel IGBT group in parallel with the capacitor and the series IGBT
Into；When detecting DC Line Fault, all submodule series IGBTs in the block are turned off；The electricity is flowed through in detection respectively
The current direction of each phase of the exchange side of source converter, and proceeded as follows according to current direction：If detect certain
One phase current flows to the converter power transformer from the voltage source converter ac terminal, then the low-pressure direct that will connect the phase
Flow the parallel IGBT shutdown in the block of side submodule, while by the parallel connection in the neutral line side submodule for connecting the phase
IGBT is connected；If detecting that a certain phase current flows to the voltage source converter ac terminal from the converter power transformer,
The low-voltage direct side submodule for connecting the phase parallel IGBT in the block is connected, and the neutrality that will connect the phase
The parallel IGBT shutdown in the block of line side submodule.
Preferably, the line commutation current transformer is thyristor current transformer.
Preferably, the line commutation current transformer is 6 pulsation current transformers or 12 pulsation current transformers.
The present invention also provides a kind of DC Line Fault sweep-out method of Boost DC auto-transformer, the direct current self couplings
Transformer includes voltage source converter, line commutation current transformer is connected with the DC side of voltage source converter described in converter power transformer
Between low-voltage direct circuit and the neutral conductor or ground wire, the DC side of the line commutation current transformer is connected to hvdc transmission line
Between low-voltage direct circuit, the low-voltage direct circuit, the low-voltage direct-current end of the line commutation current transformer and the electricity
The high-voltage direct-current end of source converter links together, the exchange side of the line commutation current transformer and the voltage source unsteady flow
The exchange side of device is linked together by the converter power transformer；When detecting DC Line Fault, by the line commutation unsteady flow
Device carries out lock operation, and the phase alternating current is made to level off to drop in each phase introducing of the voltage source converter exchange side
Low voltage.
Preferably, by controlling the turn-on and turn-off of each IGBT valve groups, the phase alternating current is made to level off to drop to introduce
Low voltage.
The ac-side current of the voltage source converter is preferably based on, to control the conducting of each IGBT valve groups
And shutdown.
Preferably, the voltage source converter is by multiple low-pressure sides being connected between low-voltage direct terminal and ac terminal
IGBT valve groups and multiple neutral line side IGBT valve groups compositions being connected between neutral line terminal and ac terminal；Detection is flowed through respectively
The current direction of each phase of the exchange side of the voltage source converter, and proceeded as follows according to current direction：If inspection
It measures a certain phase current and flows to the converter power transformer from the voltage source converter ac terminal, then will connect described in the phase
The IGBT valve groups shutdown of low-voltage direct side, while the neutrality line side IGBT valve groups for connecting the phase are connected；If detect certain
One phase current flows to the voltage source converter ac terminal from the converter power transformer, then the low-pressure direct that will connect the phase
The conducting of side IGBT valve groups is flowed, and the neutrality line side IGBT valve groups for connecting the phase are turned off.
Preferably, the voltage source converter is two level voltage source current transformer of three-phase semi-bridge type, two electricity of three phase full bridge type
Level voltage source current transformer or three-level voltage source current transformer.
Preferably, the voltage source converter is semi-bridge type modular multilevel voltage source converter；The half-bridge pattern
Block multi-level voltage source current transformer is by multiple low-pressure side submodules being connected between low-voltage direct terminal and ac terminal and more
A neutral line side submodule composition being connected between neutral line terminal and ac terminal；The submodule is by capacitor, one
A series IGBT connected with the capacitor and a parallel IGBT group in parallel with the capacitor and the series IGBT
Into；When detecting DC Line Fault, all submodule series IGBTs in the block are turned off；The electricity is flowed through in detection respectively
The current direction of each phase of the exchange side of source converter, and proceeded as follows according to current direction：If detect certain
One phase current flows to the converter power transformer from the voltage source converter ac terminal, then the low-pressure direct that will connect the phase
Flow the parallel IGBT shutdown in the block of side submodule, while by the parallel connection in the neutral line side submodule for connecting the phase
IGBT is connected；If detecting that a certain phase current flows to the voltage source converter ac terminal from the converter power transformer,
The low-voltage direct side submodule for connecting the phase parallel IGBT in the block is connected, and the neutrality that will connect the phase
The parallel IGBT shutdown in the block of line side submodule.
Preferably, the line commutation current transformer is thyristor current transformer.
Preferably, the line commutation current transformer is 6 pulsation current transformers or 12 pulsation current transformers.
By using the method for proposition, Boost DC auto-transformer can eliminate direct-current short circuit electric current.This means that
Other than realizing voltage conversion, voltage boosting dc auto-transformer can also realize the function of dc circuit breaker, the technology simultaneously
The development of high voltage direct current and DC grid will be pushed.
Description of the drawings
Fig. 1 is the topological diagram of Boost DC auto-transformer；
Fig. 2 is the DC Line Fault reset procedure of the embodiment of the present invention one；
Fig. 3 is the DC Line Fault reset procedure of the embodiment of the present invention two.
Fig. 4 is the DC Line Fault reset procedure of the embodiment of the present invention three.
Fig. 5 is the DC Line Fault reset procedure of the embodiment of the present invention four.
Specific embodiment
The present invention proposes a kind of modulator approach for removing direct-current short circuit failure.Below with reference to attached drawing, the present invention is given
Optional embodiment specific descriptions.
With reference to such as Fig. 1~2, embodiment one is described in detail.
Direct current auto-transformer shown in FIG. 1 includes voltage source converter (Voltage Source Converter, VSC)
11st, line commutation current transformer (Line Commutated Converter, LCC) 12 and converter power transformer 13, voltage source converter
11 DC side is connected between low-voltage direct circuit and the neutral conductor or ground wire, and the DC side of line commutation current transformer 12 is connected to
Between hvdc transmission line and low-voltage direct circuit, low-voltage direct circuit, the line commutation current transformer 12 low-voltage direct-current
End and the high-voltage direct-current end of voltage source converter 11 link together, and the exchange side and voltage source of line commutation current transformer 12 become
Stream device ac terminal 11 ' is linked together by the converter power transformer 13.
For Boost DC auto-transformer as shown in Figure 1, it is assumed that low-pressure side (input side) DC voltage/current is
400kV/4kA；High-pressure side (outlet side) DC voltage/current is 800kV/2kA, above-mentioned to be only assumed as a kind of example, should not be managed
It solves as limitation of the present invention.After commutator transformer Control protection system detects on high-tension side direct-current short circuit electric current, force
The phase shift of LCC Trigger Angles is to being more than 90 °, so that the operating mode of LCC switchs to inverter operating mode.The DC voltage of LCC
Polarity also will be inverted accordingly.
As shown in Fig. 2, direct current auto-transformer, when on high-tension side direct-current short circuit failure occurs, fault current can be regarded as
It is provided by two parts：DC source on 400kV circuits, is denoted as If_DC；Alternating current source from VSC inverters, is denoted as If_
AC.By using method proposed by the present invention, when detecting high-pressure side DC Line Fault, LCC will turn into inverter operation pattern,
VSC will turn into PWM rectifier pattern simultaneously.It by this method, will be even anti-by control by the If_AC from VSC transverters
Turn；If the DC voltage of LCC inverter sides is more than VSC rectified voltages, fault current DC component If_DC will decrease to zero.
When DC Line Fault occurs, just in commutation, commutation several times may occur during failure for DC current, and pass through
Converter power transformer induces corresponding fault current in VSC exchange side.During current commutation, direct-current short circuit failure can be equivalent
Three-phase alternating current short trouble for VSC exchange side.After commutation, direct current interruption failure can be equivalent to VSC exchange side
Two-phase ac short circuit failure.
Phase shift operation, failure are forced by VSC alternating voltages regulating power reliable during ac short circuit failure and LCC
Electric current levels off to reversely, is reduced to zero so as to fulfill fault current and removes the short trouble.
Further preferred scheme is, for acceleration disturbance reset procedure, the modulation degree of VSC (Modulation Index,
MI it) will be increased to its maximum value.The purpose for increasing MI is that LCC inverters is allow to obtain maximum DC voltage so as to accelerate directly
It flows back to DC current fall off rate in road and finally DC current is made to be reduced to zero.
The method that embodiment one proposes can be used for booster type mixed DC auto-transformer.This method passes through direct current self coupling
Transformer itself realizes DC Line Fault removing.Compared with double VSC direct currents auto-transformers, the scheme proposed has significantly
Advantage.
Above-mentioned in the description of embodiment one, the topological structure of VSC can be that two level voltage source of three-phase semi-bridge type becomes
Flow device or the voltage source converter (VSC) of other well known topology, such as two level VSC of three phase full bridge type, three level VSC, module
Change more level VSC etc.；The topological structure of LCC can be 6 pulsation current transformers or the thyristor current transformer based on other known technologies
Such as 12 pulsation current transformers.
With reference to such as Fig. 1 and Fig. 3, embodiment two is described in detail.
After commutator transformer Control protection system detects on high-tension side direct-current short circuit electric current, LCC Trigger Angles will be forced
Phase shift is to being more than 90 °, so that the operating mode of LCC switchs to inverter operating mode.The DC voltage polarity of LCC is also by phase
It should invert.Or lock operation is carried out to LCC, that is, block the trigger signal of thyristor all in LCC.
By introducing the voltage that the phase alternating current is made to level off to reduction in each phase of 11 exchange side of voltage source converter,
Preferably, the phase can be made by controlling the turn-on and turn-off of each insulated gate bipolar transistor IGBT valve group to introduce
Alternating current levels off to the voltage of reduction；It is further preferably, based on the bridge arm current of voltage source converter 11, to control
State the turn-on and turn-off of IGBT valve groups, the method that the IGBT valve groups on VSC inverter legs can be proposed according to embodiment two, phase
That answers being switched on or turning off, to reduce and finally eliminate fault current.
Mixed type direct current auto-transformer (the 6 pulsation LCC+ three-phases semi-bridge types two as shown in Figure 3 of the present embodiment two
Level VSC) illustrate the principle of proposed method.Assuming that when short trouble occurs, No. 5 thyristor valves in LCC rectifiers
It is being connected with No. 6 thyristor valves.Fault current is made of two parts.A part is straight as caused by 400kV direct voltage sources
Flow short-circuit current component, another part are the alternating short-circuit current components as caused by VSC inversion alternating voltages.
In order to eliminate fault current, the phase shift of LCC Trigger Angles will be forced to being more than 90 °, so that the operating mode of LCC turns
For inverter operating mode, the DC voltage polarity of LCC also will be inverted accordingly；Or locking LCC.Meanwhile the IGBT on VSC bridge arms
Valve group (number 1 ', 2 ', 3 ', 4 ', 5 ' and 6 ') will be switched on or turn off according to the current direction for flowing through A phases, B phases and C phases.
Electric current positive direction is defined as follows as shown in Figure 3：Transformer winding is flowed to from transverter ac terminal.
1. if the electric current of A phases is positive, 1 ' number IGBT valve group is turned off, and 2 ' numbers IGBT valve groups are switched on.Such as
The electric current of fruit A phases is negative, then 1 ' number IGBT valve group is switched on, and 2 ' numbers IGBT valve groups are turned off.
2. if the electric current of B phases is positive, 3 ' numbers IGBT valve groups are turned off, and 4 ' numbers IGBT valve groups are switched on.Such as
The electric current of fruit B phases is negative, then 3 ' numbers IGBT valve groups are switched on, and 4 ' numbers IGBT valve groups are turned off.
3. if the electric current of C phases is positive, 5 ' numbers IGBT valve groups are turned off, and 6 ' numbers IGBT valve groups are switched on.Such as
The electric current of fruit C phases is negative, then 5 ' numbers IGBT valve groups are switched on, and 6 ' numbers IGBT valve groups are turned off.
It is described to simplify, 1 ', 3 ', 5 ' valve groups in IGBT valve groups is known as low-voltage direct side IGBT valve groups, 2 ', 4 ', 6 '
Valve group is known as neutral line side IGBT valve groups.
The control of valve group is：The current direction of each phase of the exchange side of detection stream overvoltage source current transformer 11 respectively, and
It is proceeded as follows according to current direction：
If 1. detect that a certain phase current flows to converter power transformer 13 from IGBT valve groups, by connect the phase some is low
The shutdown of DC side IGBT valve groups is pressed, while some the neutrality line side IGBT valve group for connecting the phase is connected；
If 2. detect that a certain phase current flows to IGBT valve groups from converter power transformer 13, by connect the phase some is low
The conducting of DC side IGBT valve groups is pressed, and some the neutrality line side IGBT valve group for connecting the phase is turned off.
With this method, one can be introduced in each phase makes the phase alternating current level off to the voltage of reduction, comes clear
Except fault current.
Above-mentioned in the description of embodiment two, the topological structure of VSC belongs to two level voltage source unsteady flow of three-phase semi-bridge type
Device, it is above-mentioned to be only assumed as a kind of example, it should not be construed as limiting the invention.It is proposed by the present invention applied to embodiment two
Method (introducing one in VSC exchange side makes the phase alternating current level off to the voltage of reduction), can also be applied to based on other public affairs
Know the voltage source converter (VSC) of topology, such as two level VSC of three phase full bridge type, modular multilevel VSC etc..The topology of LCC
Structure can be 6 pulsation current transformers or pulsation current transformer of thyristor current transformer such as 12 based on other known technologies etc..
Mixed type direct current auto-transformer (the 6 pulsation LCC+ diode clamp bit-types as shown in Figure 4 of the present embodiment three
Three level VSC) illustrate the principle of proposed method.Assuming that when short trouble occurs, No. 5 thyristors in LCC rectifiers
Valve and No. 6 thyristor valves are being connected.Fault current is made of two parts.A part is as caused by 400kV direct voltage sources
Direct-current short circuit current component, another part are the alternating short-circuit current components as caused by VSC inversion alternating voltages.
In order to eliminate fault current, the phase shift of LCC Trigger Angles will be forced to being more than 90 °, so that the operating mode of LCC turns
For inverter operating mode, the DC voltage polarity of LCC also will be inverted accordingly；Or locking LCC.Meanwhile the IGBT on VSC bridge arms
Valve group (number A1, A2, A3, A4；B1, B2, B3, B4；C1, C2, C3, C4) it will be according to the electric current side for flowing through A phases, B phases and C phases
To switched on or shutdown.Electric current positive direction is defined as follows as shown in Figure 4：Transformer winding is flowed to from transverter ac terminal.
1. if the electric current of A phases is positive, A1, A2 IGBT valve groups are turned off, and A3, A4 IGBT valve groups are led
It is logical.If the electric current of A phases is negative, A1, A2 IGBT valve groups are switched on, and A3, A4 IGBT valve groups are turned off.
2. if the electric current of B phases is positive, B1, B2 IGBT valve groups are turned off, and B3, B4 IGBT valve groups are led
It is logical.If the electric current of B phases is negative, B1, B2 IGBT valve groups are switched on, and B3, B4 IGBT valve groups are turned off.
3. if the electric current of C phases is positive, C1, C2 IGBT valve groups are turned off, and C3, C4 IGBT valve groups are led
It is logical.If the electric current of C phases is negative, C1, C2 IGBT valve groups are switched on, and C3, C4 IGBT valve groups are turned off.
With this method, one can be introduced in each phase makes the phase alternating current level off to the voltage of reduction, comes clear
Except fault current.
Above-mentioned to being only assumed as a kind of example in the description of embodiment three, should not be construed as limiting the invention.
(introduce one in VSC exchange side makes the phase alternating current level off to reduction to method proposed by the present invention applied to embodiment three
Voltage), can also be applied to the voltage source converter (VSC) based on other well known topology.The topological structure of LCC can be 6 arteries and veins
Move current transformer or pulsation current transformer of thyristor current transformer such as 12 based on other known technologies etc..
Mixed type direct current auto-transformer (the 6 pulsation LCC+ modular multilevels as shown in Figure 5 of the present embodiment four
Type VSC) illustrate the principle of proposed method.Assuming that when short trouble occurs, No. 5 thyristor valves and 6 in LCC rectifiers
Number thyristor valve is being connected.Fault current is made of two parts.A part is that the direct current as caused by 400kV direct voltage sources is short
Road current component, another part are the alternating short-circuit current components as caused by VSC inversion alternating voltages.
In order to eliminate fault current, the phase shift of LCC Trigger Angles will be forced to being more than 90 °, so that the operating mode of LCC turns
For inverter operating mode, the DC voltage polarity of LCC also will be inverted accordingly；Or locking LCC.Meanwhile the IGBT on VSC bridge arms
Valve group (number A1a, A1b, A2a, A2b... Ana, Anb；A’1a, A '1b, A '2a, A '2b... A 'na, A 'nb；B1a, B1b, B2a,
B2b... Bna, Bnb；B’1a, B '1b, B '2a, B '2b... B 'na, B 'nb；C1a, C1b, C2a, C2b... Cna, Cnb；C’1a, C '1b, C
’2a, C '2b... C 'na, C 'nb；) will be switched on or turn off according to the current direction for flowing through A phases, B phases and C phases.Electric current positive direction
It is defined as follows as shown in Figure 5：Transformer winding is flowed to from transverter ac terminal.
1. IGBT (the number A that will be connected in all submodules with capacitor1b, A2b... Anb；A’1b, A '2b... A
’nb；B1b, B2b... Bnb；B’1b, B '2b... B 'nb；C1b, C2b... Cnb；C’1b, C '2b... C 'nb；) shutdown, to prevent capacitance
Device passes through this series IGBT and parallel IGBT (number A1a, A2a... Ana；A’1a, A '2a... A 'na；B1a, B2a... Bna；
B’1a, B '2a... B 'na；C1a, C2a... Cna；C’1a, C '2a... C 'na；) short circuit.
2. if the electric current of A phases is positive, A1a, A2a... AnaNumber IGBT valve groups are turned off, and A '1a, A '2a,
...A’naNumber IGBT valve groups are switched on.If the electric current of A phases is negative, A1a, A2a... AnaNumber IGBT valve groups are switched on, and
And A '1a, A '2a... A 'naNumber IGBT valve groups are turned off.
3. if the electric current of B phases is positive, B1a, B2a... BnaNumber IGBT valve groups are turned off, and B '1a, B '2a,
...B’naNumber IGBT valve groups are switched on.If the electric current of B phases is negative, B1a, B2a... BnaNumber IGBT valve groups are switched on, and
And B '1a, B '2a... B 'naNumber IGBT valve groups are turned off.
4. if the electric current of C phases is positive, C1a, C2a... CnaNumber IGBT valve groups are turned off, and C '1a, C '2a,
...C’naNumber IGBT valve groups are switched on.If the electric current of C phases is negative, C1a, C2a... CnaNumber IGBT valve groups are switched on, and
And C '1a, C '2a... C 'naNumber IGBT valve groups are turned off.
With this method, one can be introduced in each phase makes the phase alternating current level off to the voltage of reduction, comes clear
Except fault current.
A kind of example is only assumed as in the above-mentioned description to example IV, should not be construed as limiting the invention.
(introduce one in VSC exchange side makes the phase alternating current level off to reduction to method proposed by the present invention applied to example IV
Voltage), can also be applied to the voltage source converter (VSC) based on other well known topology.The topological structure of LCC can be 6 arteries and veins
Move current transformer or pulsation current transformer of thyristor current transformer such as 12 based on other known technologies etc..
In conclusion the method that embodiment two, three, four proposes can be used for the event of booster type mixed DC auto-transformer
Barrier is removed.This method itself realizes DC Line Fault by direct current auto-transformer and removes.With double VSC direct currents auto-transformer phases
Than the scheme proposed has apparent advantage.
In DC Line Fault reset procedure, line commutation transverter LCC is converted into inverter operation pattern, in order to realize
The conversion of the operation mode needs to make certain limitation to the step-up ratio minimum value of commutator transformer.If step-up ratio is less than 2,
Fault clearance will will become relatively difficult.In this case, the DC Line Fault of high-voltage side can be proposed by ABB
Dc circuit breaker remove.
Although disclosing presently preferred embodiments of the present invention and attached drawing for the purpose of illustration, the people of skilled
Member without departing from the spirit and scope of the invention and the appended claims, can make various replacements, variation and retouching.Therefore,
The present invention should not be limited to preferred embodiment and attached drawing disclosure of that, and protection scope of the present invention is with appended claim
Subject to the range that book is defined.
Claims (22)
1. a kind of DC Line Fault sweep-out method of Boost DC auto-transformer, it is characterised in that：The direct current self coupling transformation
Device includes voltage source converter (VSC) (11), line commutation current transformer (LCC) (12) and converter power transformer (13), the voltage
The DC side of source current transformer (11) is connected between low-voltage direct circuit and the neutral conductor or ground wire, the line commutation current transformer
(12) DC side is connected between hvdc transmission line and low-voltage direct circuit, and the low-voltage direct circuit, the power grid change
The low-voltage direct-current end of phase current transformer (12) and the high-voltage direct-current end of the voltage source converter (11) link together, described
The exchange side of line commutation current transformer (12) and the exchange side of the voltage source converter (11) pass through the converter power transformer
(13) it links together；
When detecting DC Line Fault, the line commutation current transformer (12) is converted into inverter pattern by rectifier pattern,
And the voltage that the phase alternating current is made to level off to reduction is introduced in each phase of the voltage source converter (11) exchange side.
2. according to the method described in claim 1, it is characterized in that：By the Trigger Angle phase shift of the line commutation current transformer (12)
To more than 90 degree.
3. method according to claim 1 or 2, it is characterised in that：The voltage source converter (11) is by inverter pattern
Be converted to rectifier pattern.
4. method according to claim 1 or 2, it is characterised in that：The modulation degree of the voltage source converter (11) is increased
Add.
5. according to the method described in claim 3, it is characterized in that：The modulation degree of the voltage source converter (11) is increased.
6. according to the method described in claim 4, it is characterized in that：The modulation degree of the voltage source converter (11) is increased to
Maximum value.
7. according to the method described in claim 1, it is characterized in that：By controlling each insulated gate bipolar transistor (IGBT)
The turn-on and turn-off of valve group, to introduce the voltage that the phase alternating current is made to level off to reduction.
8. according to the method described in claim 7, it is characterized in that：Exchange side electricity based on the voltage source converter (11)
Stream, to control the turn-on and turn-off of each IGBT valve groups.
9. method according to claim 7 or 8, it is characterised in that：The voltage source converter (11) is connected to by multiple
Low-pressure side IGBT valve groups (1 ', 3 ', 5 ') between low-voltage direct terminal and ac terminal and multiple it is connected to neutral line terminal and friendship
Flow neutral line side IGBT valve groups (2 ', 4 ', 6 ') composition between terminal；
The current direction of each phase of the exchange side of the voltage source converter (11) is flowed through in detection respectively, and according to current direction
It proceeds as follows：
If detect that a certain phase current flows to the converter power transformer from the voltage source converter ac terminal (11 ')
(13), then the low-voltage direct side IGBT valve groups (1 '/3 '/5 ') for connecting the phase are turned off, while will connect described in the phase
Neutral line side IGBT valve groups (2 '/4 '/6 ') conducting；
If detect that a certain phase current flows to the voltage source converter ac terminal from the converter power transformer (13)
(11 ') then the low-voltage direct side IGBT valve groups (1 '/3 '/5 ') for connecting the phase are connected, and will connect described in the phase
Neutral line side IGBT valve groups (2 '/4 '/6 ') shutdown.
10. according to the method described in claims 1 or 2 or 5 or 7 or 8, it is characterised in that：The voltage source converter (11) is
Two level voltage source current transformer of three-phase semi-bridge type, two level voltage source current transformer of three phase full bridge type or three-level voltage source unsteady flow
Device.
11. method according to claim 7 or 8, it is characterised in that：The voltage source converter (11) is semi-bridge type module
Change multi-level voltage source current transformer；The voltage source converter (11) is connected to low-voltage direct terminal and ac terminal by multiple
Low-pressure side submodule and multiple neutral line side submodule compositions being connected between neutral line terminal and ac terminal between (11 ')；
The submodule is by a capacitor, a series IGBT connected with the capacitor and one and the capacitor and described
The parallel IGBT composition of series IGBT parallel connection；
When detecting DC Line Fault, all submodule series IGBTs in the block are turned off；
The current direction of each phase of the exchange side of the voltage source converter (11) is flowed through in detection respectively, and according to current direction
It proceeds as follows：
If detect that a certain phase current flows to the converter power transformer from the voltage source converter ac terminal (11 ')
(13), then the low-voltage direct side submodule for connecting the phase parallel IGBT in the block is turned off, while will connect the phase
Parallel IGBT conducting in the neutrality line side submodule；
If detect that a certain phase current flows to the voltage source converter ac terminal from the converter power transformer (13)
(11 ') then the low-voltage direct side submodule for connecting the phase parallel IGBT in the block is connected, and will connect the phase
Parallel IGBT shutdown in the neutrality line side submodule.
12. according to the method described in claims 1 or 2 or 5 or 7 or 8, it is characterised in that：The line commutation current transformer (12)
For thyristor current transformer.
13. according to the method for claim 12, it is characterised in that：The line commutation current transformer (12) is 6 pulsation unsteady flows
Device or 12 pulsation current transformers.
14. a kind of DC Line Fault sweep-out method of Boost DC auto-transformer, it is characterised in that：The direct current self coupling transformation
Device includes voltage source converter (11), line commutation current transformer (12) and converter power transformer (13), the voltage source converter
(11) DC side is connected between low-voltage direct circuit and the neutral conductor or ground wire, the direct current of the line commutation current transformer (12)
Side is connected between hvdc transmission line and low-voltage direct circuit, the low-voltage direct circuit, the line commutation current transformer
(12) low-voltage direct-current end and the high-voltage direct-current end of the voltage source converter (11) links together, the line commutation
The exchange side of current transformer (12) and the exchange side of the voltage source converter (11) are connected to by the converter power transformer (13)
Together；
When detecting DC Line Fault, the line commutation current transformer (12) is subjected to lock operation, and in the voltage source
Each phase of current transformer (11) exchange side introduces the voltage that the phase alternating current is made to level off to reduction.
15. according to the method for claim 14, it is characterised in that：By controlling the turn-on and turn-off of each IGBT valve groups,
To introduce the voltage that the phase alternating current is made to level off to reduction.
16. according to the method for claim 15, it is characterised in that：Exchange side electricity based on the voltage source converter (11)
Stream, to control the turn-on and turn-off of each IGBT valve groups.
17. method according to claim 15 or 16, it is characterised in that：The voltage source converter (11) is by multiple connections
Low-pressure side IGBT valve groups (1 ', 3 ', 5 ') between low-voltage direct terminal and ac terminal and it is multiple be connected to neutral line terminal and
Neutral line side IGBT valve groups (2 ', 4 ', 6 ') composition between ac terminal；
The current direction of each phase of the exchange side of the voltage source converter (11) is flowed through in detection respectively, and according to current direction
It proceeds as follows：
If detect that a certain phase current flows to the converter power transformer from the voltage source converter ac terminal (11 ')
(13), then the low-voltage direct side IGBT valve groups (1 '/3 '/5 ') for connecting the phase are turned off, while will connect described in the phase
Neutral line side IGBT valve groups (2 '/4 '/6 ') conducting；
If detect that a certain phase current flows to the voltage source converter ac terminal from the converter power transformer (13)
(11 ') then the low-voltage direct side IGBT valve groups (1 '/3 '/5 ') for connecting the phase are connected, and will connect described in the phase
Neutral line side IGBT valve groups (2 '/4 '/6 ') shutdown.
18. according to the method described in claims 14 or 15 or 16, it is characterised in that：The voltage source converter (11) is three-phase
Two level voltage source current transformer of semi-bridge type, two level voltage source current transformer of three phase full bridge type, three-level voltage source current transformer or mould
Block multi-level voltage source current transformer.
19. according to the method for claim 17, it is characterised in that：The voltage source converter (11) is three-phase semi-bridge type two
Level voltage source current transformer, two level voltage source current transformer of three phase full bridge type or three-level voltage source current transformer.
20. method according to claim 15 or 16, it is characterised in that：The voltage source converter (11) is half-bridge pattern
Block multi-level voltage source current transformer；The voltage source converter (11) is connected to low-voltage direct terminal and ac terminal by multiple
Low-pressure side submodule and multiple neutral line side submodule compositions being connected between neutral line terminal and ac terminal between (11 ')；
The submodule is by a capacitor, a series IGBT connected with the capacitor and one and the capacitor and described
The parallel IGBT composition of series IGBT parallel connection；
When detecting DC Line Fault, all submodule series IGBTs in the block are turned off；
The current direction of each phase of the exchange side of the voltage source converter (11) is flowed through in detection respectively, and according to current direction
It proceeds as follows：
If detect that a certain phase current flows to the converter power transformer from the voltage source converter ac terminal (11 ')
(13), then the low-voltage direct side submodule for connecting the phase parallel IGBT in the block is turned off, while will connect the phase
Parallel IGBT conducting in the neutrality line side submodule；
If detect that a certain phase current flows to the voltage source converter ac terminal from the converter power transformer (13)
(11 ') then the low-voltage direct side submodule for connecting the phase parallel IGBT in the block is connected, and will connect the phase
Parallel IGBT shutdown in the neutrality line side submodule.
21. according to the method described in claims 14 or 15 or 16 or 19, it is characterised in that：The line commutation current transformer (12)
For thyristor current transformer.
22. according to the method for claim 21, it is characterised in that：The line commutation current transformer (12) is 6 pulsation unsteady flows
Device or 12 pulsation current transformers.
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| CN201410100397.1A CN104934948B (en) | 2014-03-18 | 2014-03-18 | The DC Line Fault sweep-out method of Boost DC auto-transformer |
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| CN110366812B (en) * | 2017-01-11 | 2021-11-26 | 日立能源瑞士股份公司 | Method and system for fault handling in DC power transmission |
| CN110323933B (en) * | 2019-08-07 | 2021-03-23 | 哈尔滨工业大学 | Flexible direct-current transmission DC/DC converter with fault blocking capability |
| CN112825451B (en) * | 2019-11-18 | 2022-04-19 | 南京南瑞继保电气有限公司 | Energy balance adjustment converter chain, control method, multi-section converter chain and converter |
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| CN103107551A (en) * | 2013-01-25 | 2013-05-15 | 华北电力大学 | Topology circuit used for offshore wind power electric energy delivery |
| DE102011087283A1 (en) * | 2011-11-29 | 2013-05-29 | Siemens Ag | A clocking method of a series resonant DC / DC converter of a multipoint medium frequency feed-in converter of a traction converter |
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| DE102011087283A1 (en) * | 2011-11-29 | 2013-05-29 | Siemens Ag | A clocking method of a series resonant DC / DC converter of a multipoint medium frequency feed-in converter of a traction converter |
| CN103107551A (en) * | 2013-01-25 | 2013-05-15 | 华北电力大学 | Topology circuit used for offshore wind power electric energy delivery |
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