CN105790295B - Double-end flexible direct-current transmission system power grid fault non-communication ride-through control method - Google Patents
Double-end flexible direct-current transmission system power grid fault non-communication ride-through control method Download PDFInfo
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Abstract
The invention discloses a double-end flexible direct current transmission system power grid fault non-communication ride-through control method, which comprises a Udc/QDetection and control of end faults and UdcWhen the/Q end fails, the P/Q end assists UdcThe method and the device have the advantages that the fault ride-through detection and control of the P/Q end and the fault ride-through of the P/Q end are realized, a communication line or a fault processing additional circuit is not needed, the overvoltage of the direct current bus voltage, the overcurrent of the alternating current bus current and the like are restrained, and the fault ride-through of the flexible direct current transmission system is realized.
Description
Technical field
The invention belongs to flexible DC transmission technology fields, are related to a kind of both-end flexible direct current power transmission system without communication line
Fault ride-through of power grid control method.
Background technology
When flexible direct current power transmission system joins (such as single-phase earthing, phase fault and three-phase when AC network breaks down
Shorted to earth), it is desirable that flexible direct current power transmission system can continue to run, and does not occur locking and stops transport, reduces and AC system is rushed
It hits, while ensures equipment of itself safety, do not occur device over-voltage and over-current, realize fault traversing.Up to the present, existing method master
It is divided into two classes：One kind is the adjunct circuit in flexible direct current power transmission system, achievees the purpose that discharge dump power；In addition it is a kind of
It is the control strategy of modification system, but the control strategy that can be related to wherein one end uses associated voltage and electric current of opposite end etc.
Information, it is therefore desirable to which the information for realizing both ends by communication line is transmitted；It is defeated that above-mentioned two classes method can all be related to flexible direct current
The both-end communication of electric system, along with adjunct circuit, considerably increases the complexity of system, reduces system reliability, and one
When denier communication line breaks down, flexible direct current power transmission system unstability can be increased, result even in the situation that locking is stopped transport
Occur.
Invention content
In view of the problems of the existing technology, the object of the present invention is to provide a kind of both-end flexible direct current power transmission system power grids
Failure is without communication traversing control method, and the present invention needs not rely on communication line or troubleshooting adjunct circuit, so as to inhibit
DC bus-bar voltage overvoltage and ac bus overcurrent etc. realize the fault traversing of flexible direct current power transmission system.
The technical solution adopted in the present invention is that a kind of both-end flexible direct current power transmission system electric network fault passes through control without communication
Method processed, in Udc/ Q ends and P/Q ends are respectively controlled：
Udc/ Q ends control method is as follows：
Step 11：Detect Udc/ Q ends join AC system three-phase bus voltage va1、vb1、vc1, abc-dq transformation is done, is obtained
Voltage d axis components and q axis components vd1And vq1, judge vd1With the size of threshold value：Work as vd1During more than threshold value, Reflector Fa
It sets to 0, works as vd1During less than or equal to threshold value, then Reflector FaPut 1；
Step 12：The Reflector F generated according to step 11a, whether failure judgement occur, in normal conditions, Udc/Q
Hold original controlled quentity controlled variable C of current inner loop controller receiving voltage outer ring controller outputold；
As Reflector FaWhen becoming 1 (i.e. rising edge) from 0, then failure occurs, original controlled quentity controlled variable ColdValue according to
Every T1(T1>=0) new controlled quentity controlled variable C is transformed tonew, meanwhile, in elapsed time interval T1(T1>=0) after, setting switching mark a is put
1, switching mark a is as disable signal at this time, and the controller work of stopping outer voltage, switching mark a, will be former as switching signal
There is controlled quentity controlled variable ColdIt is switched to new controlled quentity controlled variable Cnew, new controlled quentity controlled variable CnewIt is applied in current inner loop controller；
New controlled quentity controlled variable CnewThe method of determining is：Remember that failure three-phase busbar voltage d axis components and q axis components are vd1With
vq1, three-phase bus voltage d axis components and q axis components are v' after remembering failured1And v'q1, three phase network most common failure includes single-phase connecing
Ground, phase fault and three-phase ground failure, under different faults, v'd1And v'q1Value be different, in consideration of it, new
Controlled quentity controlled variable is that a proportionality coefficient k is multiplied by the basis of original controlled quentity controlled variable, which determines according to the following formula,
New controlled quentity controlled variable is CnewIt is C with original controlled quentity controlled variableoldMeet following relationship：
As Reflector FaDuring to become 0 (i.e. failing edge) from 1, then failure vanishes, new controlled quentity controlled variable CnewValue according to
It is spaced T2(T2>=0) original controlled quentity controlled variable C is transformed toold, meanwhile, in elapsed time interval T2(T2>=0) after, switching mark a is set
It sets to 0, switching mark a is used as switching signal, startup outer voltage controller work, by new controlled quentity controlled variable C at this timenewIt is switched to
Original controlled quentity controlled variable Cold, original controlled quentity controlled variable ColdAgain it is applied in current inner loop controller；
P/Q ends control method is as follows：
Step 21：P/Q ends assist Udc/Q ends to realize detecting and controlling for fault traversing, and U is detected in step 11dc/ Q ends electricity
While net voltage, P/Q detects at end side outlet DC bus-bar voltage udc, under nominal situation, DC bus-bar voltage udcMore than
Low pressure threshold value and less than high pressure threshold value, Reflector FbIt sets to 0；
As DC bus-bar voltage udc>=high pressure threshold value or DC bus-bar voltage udcDuring≤low pressure threshold value, then event occurs
Barrier, Reflector FbPut 1；
Step 22：Determine new power command value P2 *, first, according to the expression formula K of proportional, integral (PI) linkp×Err
+Ki× ∫ Errdt, in formula, KpIt is proportionality coefficient, KiThe input for being integral coefficient and proportional, integral (PI) link is direct current
Busbar voltage reference value Udc* with the DC bus-bar voltage u of actual measurementdcDifference, i.e. Err=Udc*-udc, determine proportional, integral
(PI) output of link, the output and Reflector F of proportional, integral (PI) linkbIt is multiplied, as power disturbance value PΔ：
New power command value P2 *=original power command value P1 *+ power disturbance amount PΔ, by new power command value P2 *Generation
Enter P/Q ends subordinate control section；
Step 31：The Detection ＆ Controling of P/Q ends failure detect U in step 11dcWhile/Q end network voltages, P/Q is detected
End joins AC system three-phase bus voltage va2、vb2、vc2, abc-dq transformation is done, obtains voltage d axis and q axis components vd2、vq2,
Judge vd2With the size of threshold value：Work as vd2During more than threshold value, Reflector FcIt sets to 0, works as vd2Less than or equal to threshold value
When, then Reflector FcPut 1；
In normal conditions, Reflector FcOriginal controlled quentity controlled variable I is received for 0, P/Q ends current inner loop d axisd *, P/Q ends electric current
Inner ring q axis receives original controlled quentity controlled variable Iq *；
As Reflector FcWhen becoming 1 (i.e. rising edge) from 0, then failure occurs, and control P/Q ends current inner loop d axis is original
Controlled quentity controlled variable Id *Become new controlled quentity controlled variable Id * _LVRT, the original controlled quentity controlled variable I of q axisq *Become new controlled quentity controlled variable Iq * _LVRT, new electric current loop d
Axis and q axis controlled quentity controlled variable command values are determined as the following formula respectively：
In formula, Ilim、Iqm、VdmIt is total current limit, q shaft currents amplitude limit value and voltage amplitude limit value respectively；
As Reflector FcDuring to become 0 (i.e. failing edge) from 1, then failure vanishes, control P/Q end current inner loop d axis by
New controlled quentity controlled variable Id * _LVRTBecome original controlled quentity controlled variable Id *, q axis is by new controlled quentity controlled variable Iq * _LVRTBecome original controlled quentity controlled variable Iq *。
Further, the judgment method in the step 11 is as follows：In normal conditions, threshold value takes threshold value 1, works as vd1
During more than threshold value 1, Reflector 0 continues to judge；Work as vd1During less than or equal to threshold value 1, then Reflector puts 1,
At the same time, threshold value takes the (threshold value 2 of threshold value 2>Threshold value 1), i.e., no longer judge vd1With the size of threshold value 1, it is changed to sentence
Disconnected vd1With the size of threshold value 2：Work as vd1During less than threshold value 2, Reflector remains unchanged, and continues to judge；Work as vd1It is more than
During equal to threshold value 2, then Reflector is set to 0, and at the same time, threshold value takes threshold value 1, i.e., no longer judges vd1With threshold value 2
Size is changed to judge vd1With the size of threshold value 1.
Further, the judgment method in the step 31 is as follows：In normal conditions, threshold value takes threshold value 1, works as vd2
During more than threshold value 1, Reflector 0 continues to judge；Work as vd2During less than or equal to threshold value 1, then Reflector puts 1,
At the same time, threshold value takes the (threshold value 2 of threshold value 2>Threshold value 1), i.e., no longer judge vd2With the size of threshold value 1, it is changed to sentence
Disconnected vd2With the size of threshold value 2：Work as vd2During less than threshold value 2, Reflector remains unchanged, and continues to judge；Work as vd2It is more than
During equal to threshold value 2, then Reflector is set to 0, and at the same time, threshold value takes threshold value 1, i.e., no longer judges vd2With threshold value 2
Size is changed to judge vd2With the size of threshold value 1.
Further, in the step 21, high pressure threshold value value has threshold value 3 and threshold value 4, and wherein threshold value 3 is big
In threshold value 4, low pressure threshold value value is less than threshold value 5 by threshold value 5 and threshold value 6, wherein threshold value 6；
In normal conditions, Reflector FbIt sets to 0, high pressure thresholding takes threshold value 3, and low pressure threshold value has taken threshold value 6, fortune
DC bus-bar voltage u is judged in rowdcWith threshold value 3 and the size of threshold value 6：When threshold value 3>DC bus-bar voltage udc>Thresholding
During value 6, Reflector FbIt remains unchanged；
As DC bus-bar voltage udc>=threshold value 3 or DC bus-bar voltage udcDuring≤threshold value 6, then Reflector FbPut 1,
At the same time, high pressure threshold value value is revised as threshold value 4 by threshold value 3 or low pressure threshold value value is revised as by threshold value 6
Threshold value 5 continues to judge；When there is DC bus-bar voltage udcMore than threshold value 4 or DC bus-bar voltage udcLess than door
During the situation of limit value 5, Reflector Fb1 is remained not change；When there is DC bus-bar voltage udc≤ threshold value 4 or direct current are female
Line voltage udcDuring the situation of >=threshold value 5, then Reflector FbIt sets to 0, at the same time, by high pressure threshold value value by threshold value 4
It is changed to threshold value 3 or low pressure threshold value value is changed to threshold value 6 by threshold value 5.
Further, in the step 31,1.0≤Ilim≤ 1.5,1.0≤Iqm≤ 1.5,1.0≤Vdm≤1.5。
Compared with prior art, the present invention at least has the advantages that：
The present invention needs not rely on communication line or troubleshooting adjunct circuit, has following advantageous effect：
(1) faultless communication circuit greatly reduces the complexity of system, improves the reliability of system operation；
(2) maximum transmitted for being not zero, ensureing active power active during failure；
(3) when both sides, symmetric fault or unbalanced fault occur simultaneously for AC system one or both ends, can press down
The DC bus-bar voltage overvoltage thereby resulted in is made, ensures the safe operation of equipment.
Further, in systems in practice, DC bus-bar voltage udcIt is fluctuation, setting by two-door limit value of the invention
It is fixed, it effectively prevent DC bus-bar voltage udcThe shake back and forth of the Reflector that wave zone comes between zero and one, causes subsequent step
It repeats, improves the stability of system operation.
Description of the drawings
Fig. 1 is both-end flexible direct current power transmission system structure diagram；
Fig. 2 is Udc/ Q ends Reflector Fa judges figure；
Fig. 3 is Udc/ Q ends controlled quentity controlled variable generation schematic diagram；
Fig. 4 is Udc/ Q ends switching mark a generates schematic diagram；
Fig. 5 is Udc/ Q ends Fault Control logical schematic；
Fig. 6 is UdcDuring/Q end failures, U is assisted at P/Q endsdcFault traversing is realized at/Q ends, is carried out Reflector and is judged figure；
Fig. 7 is UdcDuring/Q end failures, U is assisted at P/Q endsdcFault traversing is realized at/Q ends, and power is generated using proportional, integral
Disturbance quantity P△Schematic diagram；
Fig. 8 is UdcDuring/Q end failures, U is assisted at P/Q endsdcRealize that fault traversing generates new power instruction schematic diagram in/Q ends.
When Fig. 9 and Figure 10 is P/Q ends failure, Fault Control logic chart, wherein, Fig. 9 is controlled for P/Q ends current inner loop d axis
Switching control schematic diagram is measured, Figure 10 is P/Q ends electric current loop q axis controlled quentity controlled variable switching control schematic diagrames.
Specific embodiment
The present invention is described in detail with reference to the accompanying drawings and detailed description.
As shown in Figure 1, in the present embodiment, goal systems is both-end flexible direct current power transmission system, and the system is wherein
One end is connected with AC network, operates in integrated mode (the i.e. U of DC bus-bar voltage control and Reactive Power Controldc/ Q mode,
UdcRepresent to control the end DC bus-bar voltage, Q represents to control the end reactive power), for following convenience, it is defined as Udc/ Q ends；
Other end is connected with another AC network, operates in active power controller and integrated mode (the i.e. P/Q moulds of Reactive Power Control
Formula, P represent the end active power, and Q represents the end reactive power), it is defined as P/Q ends, Udc/ Q ends pass through dc bus with P/Q ends
It is connected, that any failure communication or troubleshooting adjunct circuit is not configured in system.
Work as UdcDuring the AC system grid voltage sags of/Q ends, other than can over-voltage and over-current occur for the end line or device, connection
Meet the DC bus-bar voltage u of two end systemsdcAlso it can fluctuate, Udc/ Q ends can directly detect voltage ripple of power network, send out
Reflector enables the control strategy of local terminal configuration, the end line or device is inhibited over-voltage and over-current occur, still, couples both ends
The DC bus-bar voltage u of systemdcStill it can fluctuate, this is because caused by the system power imbalance of both ends, need at this time
P/Q ends assist to be adjusted power to achieve the purpose that stable DC busbar voltage, and since both ends do not communicate, P/Q ends can not
Directly acquire Udc/The Reflector at Q ends, still, P/Q ends can be by detecting homonymy DC bus-bar voltage udc, and according to its electricity
Whether pressure fluctuation is more than upper limit value or lower limiting value, whether to judge current system in malfunction, if a failure occurs, then
Corresponding control strategy is enabled, the mistake that DC bus-bar voltage fluctuates and the end line or device are likely to occur is inhibited to press through
Stream, that is, work as UdcControl method during the AC system grid voltage sags of/Q ends, including UdcThe Detection ＆ Controling of/Q ends failure and
UdcDuring/Q end failures, U is assisted at P/Q endsdcRealize detecting and controlling for fault traversing in/Q ends；
Work as P/During the AC system grid voltage sags of Q ends, Udc/ Q still continues to use control method proposed in this paper in end, without doing
Modification, P/Q ends are then by changing active power command value so that both ends power reaches balance, at the same time, joins friendship to local terminal
Streaming system exports certain reactive power, supports network voltage, that is, includes the Detection ＆ Controling of P/Q ends ancient costume.
In present embodiment, both-end flexible direct current power transmission system electric network fault is without communication traversing control method, comprising as follows
Specific steps：
UdcThe Detection ＆ Controling of/Q ends failure：
Step 11：Detect Udc/ Q ends join AC system three-phase bus voltage va1、vb1、vc1, abc-dq transformation is done, is obtained
Voltage d axis and q axis components vd1、vq1, as shown in Fig. 2, under nominal situation, vd1Near rated value, Reflector FaIt sets to 0, runs
Middle judgement d axis components (i.e. ac bus voltage positive-sequence component) vd1With the size of threshold value, under nominal situation, threshold value takes thresholding
Value 1, works as vd1During more than threshold value 1, Reflector FaIt is 0, continues to judge；Work as vd1During less than or equal to threshold value 1, then event
Barrier mark Fa1 is put, at the same time, threshold value takes the (threshold value 2 of threshold value 2>Threshold value 1), i.e., no longer judge vd1With threshold value 1
Size is changed to judge vd1With the size of threshold value 2：Work as vd1During less than threshold value 2, Reflector FaIt remains unchanged, continues
Judge；Work as vd1During more than or equal to threshold value 2, then Reflector FaIt sets to 0, at the same time, threshold value takes threshold value 1, i.e., no longer sentences
Disconnected vd1With the size of threshold value 2, it is changed to judge vd1With the size of threshold value 1, repeatedly aforementioned process later, because in real system
In, d axis components vd1It is fluctuation, therefore the purpose of two threshold values is set, effectively prevent d axis components vd1The failure that wave zone comes
Indicate FaShake back and forth between zero and one, causes subsequent step to repeat；
Step 12：The Reflector F generated according to step 1a, whether failure judgement occurs, as Reflector FaWhen being 1, then
Failure occurs, as Reflector FaWhen being 0, then failure vanishes；As shown in figure 5, in normal conditions, UdcThe current inner loop control of/Q ends
Original controlled quentity controlled variable C of device receiving voltage outer ring controller output processedold, according to Reflector, determine new controlled quentity controlled variable Cnew；
Referring to Fig. 3 and Fig. 4, as Reflector FaWhen becoming 1 (i.e. rising edge) from 0, then failure occurs, original controlled quentity controlled variable
ColdValue according to interval T1(T1>=0) new controlled quentity controlled variable C is transformed tonew, meanwhile, in elapsed time interval T1(T1>=0) after,
Setting switching mark a puts 1, and switching mark a stops the work of outer voltage controller, switching mark a makees as disable signal at this time
For switching signal, by original controlled quentity controlled variable ColdIt is switched to new controlled quentity controlled variable Cnew, new controlled quentity controlled variable CnewIt is applied to current inner loop control
In device, in this step, first by original controlled quentity controlled variable ColdValue to new controlled quentity controlled variable CnewTransformation says original control after the completion of transformation
Amount C processedoldTo new controlled quentity controlled variable CnewSwitching avoids switching and fluctuation is brought to impact power grid；
New controlled quentity controlled variable CnewThe method of determining is：Remember that failure three-phase busbar voltage d axis components and q axis components are vd1With
vq1, three-phase bus voltage d axis components and q axis components are v' after remembering failured1And v'q1, three phase network most common failure includes single-phase connecing
Ground, phase fault and three-phase ground failure, under different faults, v'd1And v'q1Value be different, in consideration of it, new
Controlled quentity controlled variable is that a proportionality coefficient k is multiplied by the basis of original controlled quentity controlled variable, which determines according to the following formula,
New controlled quentity controlled variable is CnewIt is C with original controlled quentity controlled variableoldMeet following relationship：
With reference to Fig. 3 and Fig. 4, as Reflector FaDuring to become 0 (i.e. failing edge) from 1, then failure vanishes, new controlled quentity controlled variable
CnewValue according to interval T2(T2>=0) original controlled quentity controlled variable C is transformed toold, meanwhile, in elapsed time interval T2(T2>=0) after,
Setting switching mark a is set to 0, and switching mark a is used as switching signal, startup outer voltage controller work, by new control at this time
Amount C processednewIt is switched to original controlled quentity controlled variable Cold, original controlled quentity controlled variable ColdAgain it is applied in current inner loop controller, this step is similary
It effectively prevents directly carrying out the impact that controlled quentity controlled variable switching brings power grid；
UdcDuring/Q end failures, U is assisted at P/Q endsdcRealize detecting and controlling for fault traversing in/Q ends：
Step 21：U is detected in step 11dcWhile/Q end network voltages, P/Q detects at end the side outlet DC bus-bar voltage
udc, under nominal situation, DC bus-bar voltage udcMore than low pressure threshold value and less than high pressure threshold value, Reflector FbIt sets to 0；
As DC bus-bar voltage udc>=high pressure threshold value or DC bus-bar voltage udcDuring≤low pressure threshold value, then event occurs
Barrier, Reflector FbPut 1；
Referring to Fig. 6, high pressure threshold value value has threshold value 3 and threshold value 4, and wherein threshold value 3 is more than threshold value 4, low pressure
Threshold value value is less than threshold value 5 by threshold value 5 and threshold value 6, wherein threshold value 6；
In normal conditions, Reflector FbIt sets to 0, high pressure thresholding takes threshold value 3, and low pressure threshold value has taken threshold value 6, fortune
DC bus-bar voltage u is judged in rowdcWith threshold value 3 and the size of threshold value 6：When threshold value 3>DC bus-bar voltage udc>Thresholding
During value 6, Reflector FbIt remains unchanged；
As DC bus-bar voltage udc>=threshold value 3 or DC bus-bar voltage udcDuring≤threshold value 6, then Reflector FbPut 1,
At the same time, high pressure threshold value value is revised as threshold value 4 by threshold value 3 or low pressure threshold value value is revised as by threshold value 6
Threshold value 5 continues to judge；When there is DC bus-bar voltage udcMore than threshold value 4 or DC bus-bar voltage udcLess than door
During the situation of limit value 5, Reflector Fb1 is remained not change；When there is DC bus-bar voltage udc≤ threshold value 4 or direct current are female
Line voltage udcDuring the situation of >=threshold value 5, then Reflector FbIt sets to 0, at the same time, by high pressure threshold value value by threshold value 4
It is changed to threshold value 3 or low pressure threshold value value is changed to threshold value 6 by threshold value 5, later repeatedly aforementioned process, because in reality
In system, DC bus-bar voltage udcIt is fluctuation, two threshold values is set, can effectively prevent DC bus-bar voltage udcWave zone
The Reflector F comebShake back and forth between zero and one, causes subsequent step to repeat；
Step 22：Determine new power command value P2 *, first, as shown in fig. 7, the table according to proportional, integral (PI) link
Up to formula Kp× Err+ ∫ Errdt, in formula, KpIt is proportionality coefficient, KiIt is the defeated of integral coefficient and proportional, integral (PI) link
It is DC bus-bar voltage reference value U to enterdc* with the DC bus-bar voltage u of actual measurementdcDifference, i.e. Err=Udc*-udc, determine ratio
The output of example-integration (PI) link, the output and Reflector F of proportional, integral (PI) linkbIt is multiplied, as power disturbance value
PΔ, the as shown in Fig. 8 control section of P/Q ends failure, by original power command value P1 *With power disturbance amount PΔIt is overlapped
Obtain new power command value P2 *, by new power command value P2 *P/Q ends subordinate control section is substituted into, when not in the event of failure (i.e.
Reflector FbIt is 0, power disturbance amount P Δs are zero at this time, new power command value P2 *As original command value P1 *；
During the failure of P/Q ends, the Detection ＆ Controling of failure：
Step 31：U is detected in step 11dcWhile/Q end network voltages, detection P/Q ends join AC system three-phase bus
Voltage va2、vb2、vc2, abc-dq transformation is done, obtains voltage d axis and q axis components vd2、vq2, generated according to method shown in step 11
P/Q ends Reflector Fc, as shown in Figure 9 and Figure 10, according to Reflector Fc, control P/Q end current inner loop d axis and the instruction of q axis
Value, in normal conditions, Reflector FcOriginal controlled quentity controlled variable I is received for 0, P/Q ends current inner loop d axisd *, P/Q ends current inner loop q
Axis receives original controlled quentity controlled variable Iq *；
As Reflector FcWhen becoming 1 (i.e. rising edge) from 0, then failure occurs, and control P/Q ends current inner loop d axis is original
Controlled quentity controlled variable Id *Become new controlled quentity controlled variable Id * _LVRT, the original controlled quentity controlled variable I of q axisq *Become new controlled quentity controlled variable Iq * _LVRT, new current inner loop
D axis and q axis controlled quentity controlled variable command values are determined as the following formula respectively：
In formula, Ilim、Iqm、VdmIt is total current limit, q shaft currents amplitude limit value and voltage amplitude limit value respectively, specifically
Value is related with systematic parameter, under normal circumstances, IlimBetween 1.0~1.5, IqmBetween 1.0~1.5, VdmBetween 1.0~1.5；
As Reflector FcWhen becoming 0 (i.e. failing edge) from 1, then failure vanishes, the controlled quentity controlled variable of P/Q ends current inner loop d axis
By new controlled quentity controlled variable Id * _LVRTBecome original controlled quentity controlled variable Id *, the controlled quentity controlled variable of q axis is by new controlled quentity controlled variable Iq * _LVRTBecome original control
Measure Iq *。
The present invention needs not rely on communication line or troubleshooting adjunct circuit, realizes both-end flexible DC power transmission system
The fault traversing of system power grid greatly reduces the complexity of system, improves the reliability of system operation, and in age at failure
Between the active maximum transmitted for being not zero, ensureing active power；When symmetrical event occurs simultaneously for both sides AC system one or both ends
When barrier or unbalanced fault, the DC bus-bar voltage thereby resulted in can be inhibited over-pressed, ensure the safe operation of equipment, simultaneously
It is fixed to be set up present invention employs double threshold, in systems in practice, DC bus-bar voltage udcIt is fluctuation, the present invention passes through double threshold
The setting of value effectively prevent DC bus-bar voltage udcThe shake back and forth of the Reflector that wave zone comes between zero and one, after causing
Continuous step repeats, and improves the stability of system operation.
Claims (5)
1. a kind of both-end flexible direct current power transmission system electric network fault is without communication traversing control method, which is characterized in that in Udc/ Q ends
It is respectively controlled with P/Q ends：
Udc/ Q ends control method is as follows：
Step 11：Detect Udc/ Q ends join AC system three-phase bus voltage va1、vb1、vc1, abc-dq transformation is done, obtains voltage d
Axis component and q axis components vd1And vq1, judge vd1With the size of threshold value：Work as vd1During more than threshold value, Reflector FaIt sets to 0, when
vd1During less than or equal to threshold value, then Reflector FaPut 1；
Step 12：The Reflector F generated according to step 11a, whether failure judgement occur, in normal conditions, Udc/ Q ends electricity
Original controlled quentity controlled variable C that ring controller receiving voltage outer ring controller exports in streamold；
As Reflector FaFrom 0 become 1 i.e. rising edge when, then failure occur, original controlled quentity controlled variable ColdValue according to time interval
T1Transform to new controlled quentity controlled variable Cnew, wherein T1>=0, meanwhile, in elapsed time interval T1Afterwards, wherein T1>=0, switching mark is set
A puts 1, and switching mark a is as disable signal at this time, stops the work of outer voltage controller, switching mark a as switching signal,
By original controlled quentity controlled variable ColdIt is switched to new controlled quentity controlled variable Cnew, new controlled quentity controlled variable CnewIt is applied in current inner loop controller；
New controlled quentity controlled variable CnewThe method of determining is：Remember that failure three-phase busbar voltage d axis components and q axis components are vd1And vq1, note event
Three-phase bus voltage d axis components and q axis components are v' after barrierd1And v'q1, three phase network most common failure includes single-phase earthing, alternate
Short circuit and three-phase ground failure, under different faults, v'd1And v'q1Value be different, in consideration of it, new controlled quentity controlled variable is
A proportionality coefficient k is multiplied by the basis of original controlled quentity controlled variable, which determines according to the following formula,
New controlled quentity controlled variable is CnewIt is C with original controlled quentity controlled variableoldMeet following relationship：
As Reflector FaFor from 1 become 0 i.e. failing edge when, then failure vanishes, new controlled quentity controlled variable CnewValue according between the time
Every T2Transform to original controlled quentity controlled variable Cold, meanwhile, in elapsed time interval T2Afterwards, wherein T2>=0, setting switching mark a is set to 0, this
When switching mark a be used as switching signal, start the work of outer voltage controller, by new controlled quentity controlled variable CnewIt is switched to original control
Amount C processedold, original controlled quentity controlled variable ColdAgain it is applied in current inner loop controller；
P/Q ends control method is as follows：
Step 21：Assist U in P/Q endsdcDetecting and controlling for fault traversing is realized at/Q ends, and U is detected in step 11dc/ Q ends join exchange
While system three-phase bus voltage, P/Q detects at end side outlet DC bus-bar voltage udc, under nominal situation, dc bus electricity
Press udcMore than low pressure threshold value and less than high pressure threshold value when, Reflector FbIt sets to 0；
As DC bus-bar voltage udc>=high pressure threshold value or DC bus-bar voltage udcDuring≤low pressure threshold value, then break down, therefore
Barrier mark FbPut 1；
Step 22：Determine new power command value P2 *, first, according to the expression formula K of proportional, integral (PI) linkp×Err+Ki×
∫ Errdt, in formula, KpIt is proportionality coefficient, KiIt is integral coefficient, dt represents integration and proportional, integral (PI) ring to the time
The input of section is DC bus-bar voltage reference value Udc* with the DC bus-bar voltage u of actual measurementdcDifference, i.e. Err=Udc*-udc, really
The output of certainty ratio-integration (PI) link, the output and Reflector F of proportional, integral (PI) linkbIt is multiplied, as power is disturbed
Dynamic value PΔ：
New power command value P2 *=original power command value P1 *+ power disturbance value PΔ, by new power command value P2 *Substitute into P/
Q ends subordinate control section；
Step 31：The Detection ＆ Controling of P/Q ends failure detect U in step 11dc/ Q ends join AC system three-phase bus voltage
Meanwhile it detects P/Q ends and joins AC system three-phase bus voltage va2、vb2、vc2, abc-dq transformation is done, obtains voltage d axis and q axis
Component vd2、vq2, judge vd2With the size of threshold value：Work as vd2During more than threshold value, Reflector FcIt sets to 0, works as vd2It is less than or waits
When threshold value, then Reflector FcPut 1；
In normal conditions, Reflector FcOriginal controlled quentity controlled variable I is received for 0, P/Q ends current inner loop d axisd *, P/Q ends current inner loop
Q axis receives original controlled quentity controlled variable Iq *；
As Reflector FcFrom 0 become 1 i.e. rising edge when, then failure occur, control the original controlled quentity controlled variable of P/Q end current inner loop d axis
Id *Become new controlled quentity controlled variableThe original controlled quentity controlled variable I of q axisq *Become new controlled quentity controlled variableNew current inner loop d axis and q axis
Controlled quentity controlled variable command value is determined as the following formula respectively：
In formula, Ilim、Iqm、VdmIt is total current limit, q shaft currents amplitude limit value and voltage amplitude limit value respectively；
As Reflector FcFor from 1 become 0 i.e. failing edge when, then failure vanishes, control P/Q ends current inner loop d axis is by new control
AmountBecome original controlled quentity controlled variable Id *, q axis is by new controlled quentity controlled variableBecome original controlled quentity controlled variable Iq *。
2. a kind of both-end flexible direct current power transmission system electric network fault according to claim 1 without communication traversing control method,
It is characterized in that, the judgment method in the step 11 is as follows：In normal conditions, threshold value takes threshold value 1, works as vd1More than door
During limit value 1, Reflector FaIt is 0, continues to judge；Work as vd1During less than or equal to threshold value 1, then Reflector Fa1 is put, with
This simultaneously, threshold value takes threshold value 2, wherein threshold value 2>Threshold value 1, i.e., no longer judge vd1With the size of threshold value 1, it is changed to sentence
Disconnected vd1With the size of threshold value 2：Work as vd1During less than threshold value 2, Reflector FaIt remains unchanged, continues to judge；Work as vd1Greatly
When equal to threshold value 2, then Reflector FaIt sets to 0, at the same time, threshold value takes threshold value 1, i.e., no longer judges vd1With threshold value
2 size is changed to judge vd1With the size of threshold value 1.
3. a kind of both-end flexible direct current power transmission system electric network fault according to claim 1 without communication traversing control method,
It is characterized in that, the judgment method in the step 31 is as follows：In normal conditions, threshold value takes threshold value 1, works as vd2More than door
During limit value 1, Reflector FcIt is 0, continues to judge；Work as vd2During less than or equal to threshold value 1, then Reflector Fc1 is put, with
This simultaneously, threshold value takes threshold value 2, wherein threshold value 2>Threshold value 1, i.e., no longer judge vd2With the size of threshold value 1, it is changed to sentence
Disconnected vd2With the size of threshold value 2：Work as vd2During less than threshold value 2, Reflector FcIt remains unchanged, continues to judge；Work as vd2Greatly
When equal to threshold value 2, then Reflector FcIt sets to 0, at the same time, threshold value takes threshold value 1, i.e., no longer judges vd2With threshold value
2 size is changed to judge vd2With the size of threshold value 1.
4. a kind of both-end flexible direct current power transmission system electric network fault according to claim 1 without communication traversing control method,
It is characterized in that, in the step 21, high pressure threshold value value has threshold value 3 and threshold value 4, and wherein threshold value 3 is more than thresholding
Value 4, low pressure threshold value value have threshold value 5 and threshold value 6, and wherein threshold value 6 is less than threshold value 5；
In normal conditions, Reflector FbIt sets to 0, high pressure threshold value takes threshold value 3, and low pressure threshold value takes threshold value 6, in operation
Judge DC bus-bar voltage udcWith threshold value 3 and the size of threshold value 6：When threshold value 3>DC bus-bar voltage udc>Threshold value 6
When, Reflector FbIt remains unchanged；
As DC bus-bar voltage udc>=threshold value 3 or DC bus-bar voltage udcDuring≤threshold value 6, then Reflector Fb1 is put, with this
Meanwhile high pressure threshold value value is revised as threshold value 4 by threshold value 3 or low pressure threshold value value is revised as thresholding by threshold value 6
Value 5 continues to judge；When there is DC bus-bar voltage udcMore than threshold value 4 or DC bus-bar voltage udcLess than threshold value
During 5 situation, Reflector Fb1 is remained not change；When there is DC bus-bar voltage udc≤ threshold value 4 or dc bus electricity
Press udcDuring the situation of >=threshold value 5, then Reflector FbIt sets to 0, at the same time, high pressure threshold value value is changed to by threshold value 4
Low pressure threshold value value is changed to threshold value 6 by threshold value 3 by threshold value 5.
5. a kind of both-end flexible direct current power transmission system electric network fault according to claim 1 without communication traversing control method,
It is characterized in that, in the step 31,1.0≤Ilim≤ 1.5,1.0≤Iqm≤ 1.5,1.0≤Vdm≤1.5。
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| EP0554804A1 (en) * | 1992-01-30 | 1993-08-11 | Hitachi, Ltd. | Control equipment for high voltage direct current transmission system |
| CN104218573A (en) * | 2014-08-29 | 2014-12-17 | 华南理工大学 | Control method of MMC-HVDC (multi media card-high voltage direct current) during power grid malfunction of receiving end |
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| EP0554804A1 (en) * | 1992-01-30 | 1993-08-11 | Hitachi, Ltd. | Control equipment for high voltage direct current transmission system |
| CN104218573A (en) * | 2014-08-29 | 2014-12-17 | 华南理工大学 | Control method of MMC-HVDC (multi media card-high voltage direct current) during power grid malfunction of receiving end |
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