CN105186539A - Method for evaluating dynamic reactive amplitude of direct current system - Google Patents
Method for evaluating dynamic reactive amplitude of direct current system Download PDFInfo
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Abstract
The invention discloses an evaluation method of a dynamic reactive amplitude of a direct current system, which comprises the following steps: inquiring actual direct current system parameters required to be evaluated; calculating the direct current voltage during the phase commutation failure and under the condition that 2 times of rated direct current appears; calculating the upper limit of power factor angleCalculating the dynamic reactive amplitude upper limit of the direct current system converter during the fault period; estimating the direct current active power when the reactive power consumed by the direct current system converter reaches the maximum value; estimating a lower limit value of a trigger angle of the inverter side and calculating an upper limit value of a power factor angle; and calculating the dynamic reactive amplitude upper limit of the direct current system converter during fault recovery. The method does not need to carry out a large amount of simulation calculation, only needs to calculate the limit running state according to the actual direct current system parameters, has simple process and high speed, is beneficial to taking measures in time and making corresponding plans, reduces the impact of the failure fault of the direct current system commutation on the receiving end alternating current power grid, and is beneficial to the safe running of the alternating current-direct current interconnected system.
Description
Technical field
The present invention relates to operation of power networks control technology, more particularly, relate to a kind of appraisal procedure of direct current system dynamic reactive amplitude.
Background technology
AC-DC hybrid power grid has become modern power systems main development pattern in the world.Alternating current-direct current combined hybrid system, while increase system operation mode and power supply arrange flexibility, expansion transmission capacity, too increases the complexity of system configuration, brings new challenge to the safe and stable operation of electric power system.Especially the dynamic reactive change that HVDC (High Voltage Direct Current) transmission system is brought becomes the key factor affecting AC-DC hybrid power grid Transient Voltage Stability problem.
Current converter in HVDC (High Voltage Direct Current) transmission system self needs to consume a large amount of reactive powers, the change of its dynamic reactive is numerous and diverse, particularly outstanding in inverter side, its complexity can be embodied in following several aspect: (1) is when steady operation, due to capacitor compensation idle more than receiving end converter consume idle, direct current system to AC system inject idle, for AC system, direct current system is now equivalent to reactive power source, but idle amplitude is less.(2) between age at failure, because change of current busbar voltage reduces, the idle reduction of capacitor compensation, but converter still can consume a large amount of idle, now the idle of capacitor compensation cannot meet the idle of converter consumption, and direct current system will absorb idle from AC system.Now for AC system, the character that direct current system is idle changes, and direct current system is equivalent to load or burden without work.(3) after failure removal, change of current busbar voltage starts to recover, capacitor is idle also to be recovered thereupon, under the effect that direct current system controls, direct current recovers to postpone to some extent, cause idle also cannot the beginning immediately after failure removal of converter consumption to recover, the idle of capacitor compensation will flow to AC system.For AC system, direct current system is now equivalent to reactive power source.(4) after direct current starts recovery, the idle of converter consumption increases gradually, and direct current system starts again to absorb idle from AC system, and direct current system is now equivalent to load or burden without work again.
From analyzing above, for AC system, occur to the process of failure removal System recover from fault, direct current system idle dynamic change procedure is rapid, and its role constantly changes between reactive power source and load or burden without work, and vary within wide limits.And fault in ac transmission system causes direct-current commutation failure to be the most common form of alternating current-direct current dynamic interaction, and the inverter side multidigit of HVDC (High Voltage Direct Current) transmission system is in load center area, the idle reserve capabillity of receiving end AC system is often not enough, direct current system between age at failure and the idle dynamic response of follow-up Restoration stage easier receiving end AC system to be impacted, therefore, direct current system converter dynamic reactive amplitude in this process is assessed, contribute to operations staff and to analyze in transient process direct current system to the impact degree of strength of receiving end AC system, to take corresponding measure in time and to formulate urgent prediction scheme.
At present, the assessment of direct current system converter dynamic reactive amplitude places one's entire reliance upon emulation mode, namely by electromagnetic transients program or electromechanical transient simulation program, the ac and dc systems model set up also arranges all kinds of fault and carries out exhaustive simulation calculation, thus observes the idle amplitude excursion of converter.There is no the direct method that can be used to assess direct current system converter dynamic reactive amplitude of set of system.
The technical scheme of prior art:
1, scheme one
Based on electromagnetic transient in power system simulated programs such as PSCAD/EMTDC, RTDS, after equivalence is to a certain degree carried out to AC system, set up the detailed electrical-magnetic model of AC-DC interconnecting power network, wherein the detailed model of direct current system converter can the commutation dynamic process of artificial actual converter valve.After receiving end AC system arranges fault, the amplitude variation characteristic of converter dynamic reactive can be obtained by the idle curve of monitoring current converter consumption, thus to determine between age at failure and the excursion of direct current system converter dynamic reactive amplitude in follow-up recovery process.Its shortcoming is: utilize the electromagnetic transients program such as PSCAD/EMTDC, RTDS to determine between age at failure and the excursion of direct current system converter dynamic reactive amplitude in follow-up recovery process, be based upon on the basis of the detailed modeling of ac and dc systems, but its scale of model is large, the information such as the required operational factor of collecting of modeling are many, workload is large, and after detailed modeling, because model is complicated, storage data is many, cause its amount of calculation large, emulate length consuming time, the Quick requirement of through engineering approaches cannot be met.
2, scheme two
Based on Electrical-Machanical Transient Simulation of Power System programs such as PSD-BPA, after carrying out equivalence to a certain degree, set up the machine-electricity transient model of AC-DC interconnecting power network to AC system, what wherein direct current system converter model adopted is quasi steady state model.After receiving end AC system arranges fault, the amplitude variation characteristic of converter dynamic reactive can be obtained by the idle curve of monitoring current converter consumption, thus to determine between age at failure and the excursion of direct current system converter dynamic reactive amplitude in follow-up recovery process.Its shortcoming is: what the electromechanical transient simulation programs such as PSD-BPA adopted due to its direct current system converter is comparatively simple quasi steady state model, cannot the commutation dynamic process of artificial actual converter valve, the recovery commutation after the commutation failure that during causing trouble, its direct current system occurs, failure removal and follow-up recovery etc. are larger with real process otherness.Therefore, direct current system converter consumption of its calculating gained is idle exists comparatively big error with the simulation result of electrical-magnetic model or realistic model, cannot meet the requirement of engineering practicability.
Summary of the invention
The object of the invention is to: in order to direct current system in estimation of transient process is to the impact of receiving end AC system, to take corresponding measure in time according to impact degree of strength, the appraisal procedure of direct current system dynamic reactive amplitude is proposed, direct current system idle dynamic characteristic is made to have intuitive and practicality, dynamic reactive configuration for design and running human assessment ac and dc systems provides a kind of simple practical engineering method efficiently, has important directive significance to the assessment of receiving end electrical network Enhancement of Transient Voltage Stability.
To achieve these goals, the invention provides a kind of appraisal procedure of direct current system dynamic reactive amplitude.
One, appraisal procedure principle between age at failure;
In actual ac and dc systems, the dynamic reactive deposit of receiving end AC system is often not enough, so the idle dynamic characteristic of inverter side direct current system is more concerned.During ac and dc systems steady operation, if do not consider harmonic component, and the leakage reactance of converter transformer is converted valve side, then the reactive power that direct current system consumes can be tried to achieve by formula (1):
P in formula
dand Q
dfor direct current transmission power and converter consume reactive power; U
dcIfor inverter side direct voltage; E is inverter side change of current busbar voltage; I
dfor direct current; X
cfor inverter side commutating reactance; K is inverter side converter transformer no-load voltage ratio;
for power-factor angle; γ is extinguish angle; μ is angle of overlap; β is advance angle; α is Trigger Angle.
First, suppose that the change of current busbar voltage of a certain direct current system when critical commutation failure is E
cr (p.u.), inverter side extinguish angle γ=0 during commutation failure, can calculate the direct voltage during commutation failure and in appearance 2 times of rated direct current situations by formula (1).Then, according to required true direct current system practical operation situation estimation inverter side Trigger Angle excursion of carrying out assessing, this range lower limit is utilized to calculate the power-factor angle upper limit by formula (1) equally.
Finally, by above calculated direct voltage, direct current and power-factor angle by formula (2) calculate between age at failure converter consume the upper limit of idle amplitude:
Q in formula
d_upfor the upper limit of the idle amplitude of converter between age at failure; P
d_upfor amplitude idle between age at failure reaches direct current active power in limited time;
for the power-factor angle upper limit.
Its two, during fault recovery, appraisal procedure principle is as follows:
In general, the power-factor angle of converter
constant interval after Eliminating disturbance is about [30 °, 50 °], namely
for [0.58,1.2].After Eliminating disturbance, if direct voltage, direct current and direct current active power return to rated value, then the excursion of direct current reactive power is between 0.58 times to 1.2 times of its conveying active power.
During normal operation, the reactive power of inverter side direct current system consumption is about 60% of direct current active power, and according to the above results, after Eliminating disturbance, in the process that direct current system is recovered, the maximum that direct current system is idle is about 1 ￣ 2 times of rated value.But in actual motion, after failure removal, although change of current busbar voltage gets started recovery, often cannot return to rated value at once, cause direct voltage and direct current transmission power also cannot return to rated value at once.Under the effect of DC control, extinguish angle recovers gradually, Advanced firing angle reduces, commutation overlap angle returns to normal value when converter recovers commutation, and direct current due to DC control effect recover postpone to some extent, cause converter to consume idle also cannot beginning immediately after failure removal to recover, consume idlely just to recover gradually until direct current starts to recover rear converter.And then power-factor angle can be calculated by formula (3):
In formula, μ is normal angle of overlap.
Therefore, direct current system converter consume idle reach maximum time, estimation direct current recover conveying active power be about P
recover (p.u.), and further consider DC control action, i.e. the change of the power-factor angle upper limit caused by the increase of inverter side Trigger Angle, following correction made to the converter of the direct current system idle amplitude upper limit:
Q' in formula
d_upfor the upper limit of amplitude idle during fault recovery; P
recover (p.u.)for converter consume idle reach maximum time direct current recover the active power perunit value of conveying;
for considering the power-factor angle upper limit of DC control action.
Realization flow of the present invention is as follows;
One, the basic step of appraisal procedure between age at failure;
Between age at failure, the basic step of direct current system converter dynamic reactive amplitude appraisal procedure is as follows:
1, the actual DC system parameters assessed is carried out needed for inquiry;
The actual DC system detailed model parameter assessed is carried out needed for inquiry, comprising: receiving end AC system change of current bus rated voltage E
n, there is the change of current busbar voltage E of critical commutation failure in direct current system inverter side
cr (p.u.), the actual no-load voltage ratio k of inverter side converter transformer, commutating reactance X
c, rated direct current I
dN, specified transmission power P
dN, the reactive power Q that under nominal case, converter consumes
dNdeng.
2, the direct voltage during commutation failure and under there are 2 times of rated direct current situations is calculated;
Inverter side extinguish angle γ=0 during the direct current system parameter read by previous step and commutation failure, then occur that the direct voltage in 2 times of rated direct current situations is during commutation failure:
U in formula
d_2Ifor during commutation failure and the inverter side direct voltage that flows down of 2 times of rated DC current; E
crfor the famous value of change of current busbar voltage during critical commutation failure;
it is a constant term.
3, the rated output factor angle upper limit
According to required true direct current system practical operation situation determination inverter side Trigger Angle excursion of carrying out assessing, and with this excursion through type (1) rated output factor angle upper limit
generally, direct current system is when normally running, and the excursion of inverter side Trigger Angle is [95 °, 160 °], and when the system failure causes direct current system commutation failure, the scope of Trigger Angle will be decreased to [120 °, 140 °].Now, inverter side determines gamma kick will reduce Trigger Angle to increase commutation nargin, promote the recovery of commutation failure, until Trigger Angle reaches lower boundary 120 °, namely
power-factor angle
4, the direct current system converter dynamic reactive amplitude upper limit between age at failure is calculated;
According to above calculated direct voltage, direct current and power-factor angle, calculate by formula (6) upper limit that converter between age at failure consumes idle amplitude:
Q in formula
d_upfor the upper limit of amplitude idle between age at failure; P
d_upfor amplitude idle between age at failure reaches direct current active power in limited time; P
dNand Q
dNfor the reactive power that direct current system transmission power and converter under rated condition consume; K
1, K
2for power multiple.
Its two, the basic step of appraisal procedure during fault recovery;
During fault recovery, the basic step of direct current system converter dynamic reactive amplitude appraisal procedure is as follows:
1, estimation when the consumption of direct current system converter is idle reach maximum time direct current active power;
After failure removal, the idle dynamic characteristic of direct current system depends mainly on the dynamic characteristic of direct current, and direct voltage and direct current transmission power recover along with the recovery of change of current busbar voltage.According to above feature, can estimate when direct current system converter consume idle reach maximum time direct current institute recover the active-power P of conveying
recover (p.u.).
2, inverter side Trigger Angle lower limit the rated output factor angle upper limit is estimated;
DC control action after consideration failure removal, the i.e. increase of inverter side Trigger Angle, during fault recovery, the excursion of inverter side Trigger Angle should do corresponding rise, estimates and through type (3) the rated output factor angle upper limit after adjusting inverter side Trigger Angle lower limit.
3, the direct current system converter dynamic reactive amplitude upper limit during calculating fault recovery;
When direct current system converter consume idle reach maximum time, utilize direct current recover conveying power P
recover (p.u.), and consider DC control action impact, following correction is made to the converter of the direct current system idle amplitude upper limit:
Q' in formula
d_upfor the upper limit of amplitude idle during fault recovery; P
recover (p.u.)for converter consume idle reach maximum time direct current recover the active power perunit value of conveying;
for the power-factor angle upper limit during fault recovery; K '
1, K '
2for power multiple.
Compared with prior art, direct current system dynamic reactive amplitude appraisal procedure proposed by the invention, without the need to carrying out a large amount of simulation calculation, only need take into account its limit running status according to actual DC system parameters, computational process is simple, computational speed is fast, for operations staff's assessment, the dynamic reactive configuration of adjustment direct current system provides a kind of simple efficient, there is the method for practicality directly perceived, be conducive to operations staff take measures in time and formulate corresponding urgent prediction scheme, thus reduce direct current system commutation failure fault to the impact of receiving end AC network, the safe operation of AC/DC interconnected system is significant.
Accompanying drawing explanation
Fig. 1 is the basic flow sheet of appraisal procedure one embodiment of a kind of direct current system dynamic reactive of the present invention amplitude.
Embodiment
In order to make goal of the invention of the present invention, technical scheme and Advantageous Effects thereof more clear, below in conjunction with the drawings and specific embodiments, the present invention is further elaborated.Should be understood that, the embodiment described in this specification is only used to explain the present invention, is not intended to limit the present invention.
One, appraisal procedure principle between age at failure;
In actual ac and dc systems, the dynamic reactive deposit of receiving end AC system is often not enough, so the idle dynamic characteristic of inverter side direct current system is more concerned.During ac and dc systems steady operation, if do not consider harmonic component, and the leakage reactance of converter transformer is converted valve side, then the reactive power that direct current system consumes can be tried to achieve by formula (1):
P in formula
dand Q
dfor direct current transmission power and converter consume reactive power; U
dcIfor inverter side direct voltage; E is inverter side change of current busbar voltage; I
dfor direct current; X
cfor inverter side commutating reactance; K is inverter side converter transformer no-load voltage ratio;
for power-factor angle; γ is extinguish angle; μ is angle of overlap; β is advance angle; α is Trigger Angle.
First, suppose that the change of current busbar voltage of a certain direct current system when critical commutation failure is E
cr (p.u.), inverter side extinguish angle γ=0 during commutation failure, can calculate the direct voltage during commutation failure and in appearance 2 times of rated direct current situations by formula (1).Then, according to required true direct current system practical operation situation estimation inverter side Trigger Angle excursion of carrying out assessing, this range lower limit is utilized to calculate the power-factor angle upper limit by formula (1) equally.
Finally, by above calculated direct voltage, direct current and power-factor angle by formula (2) calculate between age at failure converter consume the upper limit of idle amplitude:
Q in formula
d_upfor the upper limit of the idle amplitude of converter between age at failure; P
d_upfor amplitude idle between age at failure reaches direct current active power in limited time;
for the power-factor angle upper limit.
Its two, during fault recovery, appraisal procedure principle is as follows:
In general, the power-factor angle of converter
constant interval after Eliminating disturbance is about [30 °, 50 °], namely
for [0.58,1.2].After Eliminating disturbance, if direct voltage, direct current and direct current active power return to rated value, then the excursion of direct current reactive power is between 0.58 times to 1.2 times of its conveying active power.
During normal operation, the reactive power of inverter side direct current system consumption is about 60% of direct current active power, and according to the above results, after Eliminating disturbance, in the process that direct current system is recovered, the maximum that direct current system is idle is about 1 ￣ 2 times of rated value.But in actual motion, after failure removal, although change of current busbar voltage gets started recovery, often cannot return to rated value at once, cause direct voltage and direct current transmission power also cannot return to rated value at once.Under the effect of DC control, extinguish angle recovers gradually, Advanced firing angle reduces, commutation overlap angle returns to normal value when converter recovers commutation, and direct current due to DC control effect recover postpone to some extent, cause converter to consume idle also cannot beginning immediately after failure removal to recover, consume idlely just to recover gradually until direct current starts to recover rear converter.And then power-factor angle can be calculated by formula (3):
In formula, μ is normal angle of overlap.
Therefore, direct current system converter consume idle reach maximum time, estimation direct current recover conveying active power be about P
recover (p.u.), and further consider DC control action, i.e. the change of the power-factor angle upper limit caused by the increase of inverter side Trigger Angle, following correction made to the converter of the direct current system idle amplitude upper limit:
Q' in formula
d_upfor the upper limit of amplitude idle during fault recovery; P
recover (p.u.)for converter consume idle reach maximum time direct current recover the active power perunit value of conveying;
for considering the power-factor angle upper limit of DC control action.
Refer to Fig. 1, the realization flow of the appraisal procedure of a kind of direct current system of the present invention dynamic reactive amplitude is as follows;
One, the basic step of appraisal procedure between age at failure;
Between age at failure, the basic step of direct current system converter dynamic reactive amplitude appraisal procedure is as follows:
1, the actual DC system parameters assessed is carried out needed for inquiry;
The actual DC system detailed model parameter assessed is carried out needed for inquiry, comprising: receiving end AC system change of current bus rated voltage E
n, there is the change of current busbar voltage E of critical commutation failure in direct current system inverter side
cr (p.u.), the actual no-load voltage ratio k of inverter side converter transformer, commutating reactance X
c, rated direct current I
dN, specified transmission power P
dN, the reactive power Q that under nominal case, converter consumes
dNdeng.
2, the direct voltage during commutation failure and under there are 2 times of rated direct current situations is calculated;
Inverter side extinguish angle γ=0 during the direct current system parameter read by previous step and commutation failure, then occur that the direct voltage in 2 times of rated direct current situations is during commutation failure:
U in formula
d_2Ifor during commutation failure and the inverter side direct voltage that flows down of 2 times of rated DC current; E
crfor the famous value of change of current busbar voltage during critical commutation failure;
it is a constant term.
3, the rated output factor angle upper limit
According to required true direct current system practical operation situation determination inverter side Trigger Angle excursion of carrying out assessing, and with this excursion through type (1) rated output factor angle upper limit
generally, direct current system is when normally running, and the excursion of inverter side Trigger Angle is [95 °, 160 °], and when the system failure causes direct current system commutation failure, the scope of Trigger Angle will be decreased to [120 °, 140 °].Now, inverter side determines gamma kick will reduce Trigger Angle to increase commutation nargin, promote the recovery of commutation failure, until Trigger Angle reaches lower boundary 120 °, namely
power-factor angle
4, the direct current system converter dynamic reactive amplitude upper limit between age at failure is calculated;
According to above calculated direct voltage, direct current and power-factor angle, calculate by formula (6) upper limit that converter between age at failure consumes idle amplitude:
Q in formula
d_upfor the upper limit of amplitude idle between age at failure; P
d_upfor amplitude idle between age at failure reaches direct current active power in limited time; P
dNand Q
dNfor the reactive power that direct current system transmission power and converter under rated condition consume; K
1, K
2for power multiple.
Its two, the basic step of appraisal procedure during fault recovery;
During fault recovery, the basic step of direct current system converter dynamic reactive amplitude appraisal procedure is as follows:
1, estimation when the consumption of direct current system converter is idle reach maximum time direct current active power;
After failure removal, the idle dynamic characteristic of direct current system depends mainly on the dynamic characteristic of direct current, and direct voltage and direct current transmission power recover along with the recovery of change of current busbar voltage.According to above feature, can estimate when direct current system converter consume idle reach maximum time direct current institute recover the active-power P of conveying
recover (p.u.).
2, inverter side Trigger Angle lower limit the rated output factor angle upper limit is estimated;
DC control action after consideration failure removal, the i.e. increase of inverter side Trigger Angle, during fault recovery, the excursion of inverter side Trigger Angle should do corresponding rise, estimates and through type (3) the rated output factor angle upper limit after adjusting inverter side Trigger Angle lower limit.
3, the direct current system converter dynamic reactive amplitude upper limit during calculating fault recovery;
When direct current system converter consume idle reach maximum time, utilize direct current recover conveying power P
recover (p.u.), and consider DC control action impact, following correction is made to the converter of the direct current system idle amplitude upper limit:
Q' in formula
d_upfor the upper limit of amplitude idle during fault recovery; P
recover (p.u.)for converter consume idle reach maximum time direct current recover the active power perunit value of conveying;
for the power-factor angle upper limit during fault recovery; K '
1, K '
2for power multiple.
Compared with prior art, direct current system dynamic reactive amplitude appraisal procedure proposed by the invention, without the need to carrying out a large amount of simulation calculation, only need take into account its limit running status according to actual DC system parameters, computational process is simple, computational speed is fast, for operations staff's assessment, the dynamic reactive configuration of adjustment direct current system provides a kind of simple efficient, there is the method for practicality directly perceived, be conducive to operations staff take measures in time and formulate corresponding urgent prediction scheme, thus reduce direct current system commutation failure fault to the impact of receiving end AC network, the safe operation of AC/DC interconnected system is significant.
The announcement of book and instruction according to the above description, those skilled in the art in the invention can also carry out suitable change and amendment to above-mentioned execution mode.Therefore, the present invention is not limited to embodiment disclosed and described above, also should fall in the protection range of claim of the present invention modifications and changes more of the present invention.In addition, although employ some specific terms in this specification, these terms just for convenience of description, do not form any restriction to the present invention.
Claims (8)
1. an appraisal procedure for direct current system dynamic reactive amplitude, is characterized in that, described appraisal procedure comprises the steps,
Steps A: the appraisal procedure between age at failure; And
Step B: the appraisal procedure during fault recovery;
Described steps A also comprises,
Steps A 1: carry out the actual DC system parameters assessed needed for inquiry;
Steps A 2: calculate the direct voltage during commutation failure and under there are 2 times of rated direct current situations;
Steps A 3: the rated output factor angle upper limit
Steps A 4: calculate the direct current system converter dynamic reactive amplitude upper limit between age at failure;
Described step B also comprises,
Step B1: estimation when the consumption of direct current system converter is idle reach maximum time direct current active power;
Step B2: estimate inverter side Trigger Angle lower limit and the rated output factor angle upper limit;
Step B3: the direct current system converter dynamic reactive amplitude upper limit during calculating fault recovery.
2. the appraisal procedure of direct current system dynamic reactive amplitude according to claim 1, is characterized in that, described steps A 1: carry out the actual DC system parameters assessed needed for inquiry; Comprising: receiving end AC system change of current bus rated voltage E
n, there is the change of current busbar voltage E of critical commutation failure in direct current system inverter side
cr (p.u.), the actual no-load voltage ratio k of inverter side converter transformer, commutating reactance X
c, rated direct current I
dN, specified transmission power P
dN, the reactive power Q that under nominal case, converter consumes
dN.
3. the appraisal procedure of direct current system dynamic reactive amplitude according to claim 2, is characterized in that, described steps A 2 refers to: calculate the direct voltage during commutation failure and under there are 2 times of rated direct current situations; According to described steps A 1, inverter side extinguish angle γ=0 during setting the direct current system parameter and commutation failure read, then the direct voltage during commutation failure and in appearance 2 times of rated direct current situations is:
U in formula
d_2Ifor during commutation failure and the inverter side direct voltage that flows down of 2 times of rated DC current; E
crfor the famous value of change of current busbar voltage during critical commutation failure;
it is a constant term.
4. the appraisal procedure of direct current system dynamic reactive amplitude according to claim 3, is characterized in that, in described steps A 3, and the rated output factor angle upper limit
tried to achieve by following formulae discovery:
P in formula
dand Q
dfor direct current transmission power and converter consume reactive power; U
dcIfor inverter side direct voltage; E is inverter side change of current busbar voltage; I
dfor direct current; X
cfor inverter side commutating reactance; K is inverter side converter transformer no-load voltage ratio;
for power-factor angle; γ is extinguish angle; μ is angle of overlap; β is advance angle; α is Trigger Angle.
5. the appraisal procedure of direct current system dynamic reactive amplitude according to claim 4, is characterized in that, in described steps A 4, calculates the direct current system converter dynamic reactive amplitude upper limit between age at failure and is tried to achieve by following formulae discovery:
Q in formula
d_upfor the upper limit of amplitude idle between age at failure; P
d_upfor amplitude idle between age at failure reaches direct current active power in limited time; P
dNand Q
dNfor the reactive power that direct current system transmission power and converter under rated condition consume; K
1, K
2for power multiple.
6. the appraisal procedure of direct current system dynamic reactive amplitude according to claim 1, it is characterized in that, in described step B1, estimation when the consumption of direct current system converter is idle reach maximum time direct current active power refer to: after failure removal, the idle dynamic characteristic of direct current system depends mainly on the dynamic characteristic of direct current, and direct voltage and direct current transmission power recover along with the recovery of change of current busbar voltage; Estimate thus, when direct current system converter consume idle reach maximum time direct current institute recover the active-power P of conveying
recover (p.u.).
7. the appraisal procedure of direct current system dynamic reactive amplitude according to claim 6, is characterized in that, in described step B2, can go out power-factor angle by following formulae discovery:
In formula, μ is normal angle of overlap.
8. the appraisal procedure of direct current system dynamic reactive amplitude according to claim 7, it is characterized in that, in described step B3, calculate the direct current system converter dynamic reactive amplitude upper limit during fault recovery refer to when direct current system converter consume idle reach maximum time, utilize direct current to recover the power P of conveying
recover (p.u.), and consider DC control action impact, following correction is made to the converter of the direct current system idle amplitude upper limit:
Q' in formula
d_upfor the upper limit of amplitude idle during fault recovery; P
recover (p.u.)for converter consume idle reach maximum time direct current recover the active power perunit value of conveying;
for the power-factor angle upper limit during fault recovery; K '
1, K'
2for power multiple.
Priority Applications (1)
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