CN107968434A - Wind turbine transient overvoltage analysis method under a kind of high-capacity direct current power disturbance - Google Patents

Wind turbine transient overvoltage analysis method under a kind of high-capacity direct current power disturbance Download PDF

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Publication number
CN107968434A
CN107968434A CN201711299262.2A CN201711299262A CN107968434A CN 107968434 A CN107968434 A CN 107968434A CN 201711299262 A CN201711299262 A CN 201711299262A CN 107968434 A CN107968434 A CN 107968434A
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mrow
msub
power
msubsup
mfrac
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Inventor
朱钰
潘艳
李家珏
张文朝
邵宝珠
王月荣
王刚
杨俊炜
韩子娇
孙峰
张涛
张强
王超
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State Grid Corp of China SGCC
Beijing Kedong Electric Power Control System Co Ltd
Electric Power Research Institute of State Grid Liaoning Electric Power Co Ltd
Nanjing NARI Group Corp
China EPRI Electric Power Engineering Co Ltd
Original Assignee
State Grid Corp of China SGCC
Beijing Kedong Electric Power Control System Co Ltd
Electric Power Research Institute of State Grid Liaoning Electric Power Co Ltd
Nanjing NARI Group Corp
China EPRI Electric Power Engineering Co Ltd
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Priority to CN201711299262.2A priority Critical patent/CN107968434A/en
Publication of CN107968434A publication Critical patent/CN107968434A/en
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    • H02J3/386—
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H02J3/16—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by adjustment of reactive power
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/76—Power conversion electric or electronic aspects
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The invention belongs to wind turbine transient overvoltage analysis method under field of power, more particularly to a kind of high-capacity direct current power disturbance.Comprise the following steps：Step 1：Wind turbine transient overvoltage analysis model；Step 2：Change of current busbar transient overvoltage quick calculation method during power disturbance occurs for high-capacity direct current.The present invention considers the factors such as the current conversion station transient state pressure liter that the active and reactive change of load causes node voltage to change, from single spur track voltage drop formula, derive the total differential sensitivity formula that node load change causes node voltage to change, the risk of wind turbine transient overvoltage during direct current large disturbances can effectively be assessed, so that traffic control personnel take corresponding prevention corrective action in time, the influence that dc power disturbance is stablized for sending end blower voltage is reduced, for instructing wind turbine reliability service to be of great significance.

Description

Wind turbine transient overvoltage analysis method under a kind of high-capacity direct current power disturbance
Technical field
The invention belongs to wind turbine transient overvoltage under field of power, more particularly to a kind of high-capacity direct current power disturbance Analysis method.
Background technology
In recent years, with extra-high voltage direct-current and the continuous development of generation of electricity by new energy, the installation of China's wind-powered electricity generation and grid connection capacity are not Disconnected increase, large-scale wind power are sent outside by extra-high voltage direct-current as the effective transmission of electricity side for realizing that the energy is extensive, configures on a large scale Formula.When large disturbances, including commutation failure, sending end near region ac short circuit and direct current locking etc. occur for large capacity extra-high voltage direct-current power During failure, there is the surplus of a large amount of reactive powers in sending end current conversion station and wind power plant, cause the transient overvoltage of near region wind power plant Problem, adds the risk of extensive wind turbine off-grid.In recent years, the large-scale wind power base in NORTHWEST CHINA and North China is equal There occurs the chain off-grid accident of a lot of Wind turbines.Therefore transient overvoltage analysis is also increasingly subject to operations staff and research people The attention of member, this method analyzed transient overvoltage and result it is also proposed the requirement of higher.
For sending end wind turbine transient overvoltage problem caused by high-capacity direct current power disturbance, current research is mainly concentrated The reason for the wind turbine transient overvoltage, and DC Line Fault causes the risk and its counter-measure of wind turbine off-grid accident, and to wind The research of machine transient overvoltage quantitative calculation method is then relatively fewer, and therefore, high-capacity direct current can be successfully managed by seeking one kind During generation power large disturbances it is particularly important that sending end wind turbine transient overvoltage rapid analysis method.
The content of the invention
For above-mentioned problems of the prior art, the present invention proposes that wind turbine is temporary under a kind of high-capacity direct current power disturbance State Over-voltage Analysis method.Its purpose is to from single spur track voltage drop formula, derive node load change and cause node The total differential sensitivity formula of voltage change, can effectively assess the risk of wind turbine transient overvoltage during direct current large disturbances, So that traffic control personnel take corresponding prevention corrective action in time, it is steady for sending end blower voltage to reduce dc power disturbance Fixed influence.
In order to realize foregoing invention purpose, the present invention is originally to be achieved through the following technical solutions iron：
Wind turbine transient overvoltage analysis method, comprises the following steps under a kind of high-capacity direct current power disturbance：
Step 1：Wind turbine transient overvoltage analysis model；
Step 2：Change of current busbar transient overvoltage quick calculation method during power disturbance occurs for high-capacity direct current.
The step 1 wind turbine transient overvoltage analysis model, each wind-powered electricity generation is become from 690V by two-stage boosting to boost 330kV, then by 330kV connections to 750kV main transformer 330kV sides, wind-powered electricity generation reactive-load compensation is in wind field 35kV busbares, if being The threshold voltage E such as system are 1, and U points with system pressure difference Δ of wind field is three parts：ΔUaFor wind-powered electricity generation set end voltage and 750kV main transformers 330kV sides voltage difference, Δ UbThe pressure difference between 750kV transformer 330kV sides and 750kV busbares, Δ UcFor current conversion station busbar voltage with The pressure liter of system equivalent voltage；It is assumed that under stable situation, System Reactive Power balance, each several part pressure difference is zero.
The direct current, system voltage first reduces during commutation failure occurs, and wind-powered electricity generation enters low voltage crossing shape at this time State, active reduction cause the idle surplus of wind field, and certain time, and before active power for wind power recovery, dc power is During zero, DC filter is superimposed with the idle surplus of wind turbine makes the idle surplus of wind power direct current transmitting system reach maximum, at this time Overvoltage is maximum；Consider most serious operating mode, active power is zero during wind-powered electricity generation low voltage crossing, then wind during idle surplus maximum Pressure difference specifically calculates as follows between machine and system：
According to line drop formulaNegligible resistance obtains：
X in formulaT330For 330kV transformer impedances, QACFor wind power plant 35kV grid entry point reactive-load compensations, XLFor 330kV circuits Impedance, QL1For 330kV line charging power；
X in formulaT750For 750kV transformer reactances, ∑ (QACi+QLi) filled for multiple wind power plant surplus reactive-load compensations and circuit The sum of electrical power, QDFor the reactive-load compensation of 750kV transformers.
The wind turbine transient overvoltage is caused by direct current disturbance, by wind-powered electricity generation set end voltage and 750kV main transformer 330kV sides voltage Between pressure difference, the pressure difference between 750kV transformer 330kV side voltages and 750kV change of current busbar voltages, 750kV change of current busbares Pressure difference three parts between voltage and system equivalent voltage are formed：
Δ U=Δs Ua+ΔUb+ΔUc(3)；
Δ U in formulaaFor the pressure difference between wind-powered electricity generation set end voltage and 750kV main transformer 330kV sides voltage, Δ UbFor 750kV transformations Pressure difference between device 330kV side voltages and 750kV change of current busbar voltages, Δ UcFor 750kV changes of current busbar voltage and system equivalent Pressure difference between voltage.
Change of current busbar transient overvoltage quick calculation method during power disturbance occurs for step 2 high-capacity direct current, as follows：
Wind power plant surplus is idle under high-capacity direct flow disturbance failure and current conversion station surplus is idle and the active reduction of direct current is common Same-action produces pressure and rises, empirically computational methods, and the rise of DC converter station transient voltage is：
In formula：ΔUcPress and rise for current conversion station busbar transient state；△ Q are idle for wind power plant and current conversion station surplus；S is short for current conversion station Appearance of a street amount；Qc is current conversion station reactive-load compensation filter capacity.
The wind turbine transient overvoltage analysis model, wherein, U1For system head end, active power, reactive power point are sent out Wei not P1、Q1, U2For load end, active power is sent into, reactive power is respectively P2、Q2, system head end is R through impedance with end + jX is connected, this impedance is the short-circuit equivalent impedance of change of current busbar；
Load terminal voltage U2With system head end P1、Q1Relation meet power flow equation, wherein it is assumed that U1=1：
R represents system first and last end contact line resistance in formula (5), and X represents the end interconnection reactance of system first and last；
To P1、Q1Differential of demanding perfection obtains：
In formula (6)：D represents differential；
K is the simplification symbol of above-mentioned expression formula：
If load side voltage initial value is U under system initial state20, system send out active power initial value be P10, reactive power Initial value is Q10, Δ P1、ΔQ1Respectively system head end active power, reactive power changing value, then P11=P10+ΔP1Born for end Head end active power after lotus change, Q11=Q10+ΔQ1Head end reactive power after changing for end load；
Make P in formula (5)1=P10、Q1=Q10, draw：
That is K=1/U20, so as to have：
Substitution formula (6) can obtain terminal voltage variation delta U2：
Capacity of short circuitSubstitution formula (8)：
Line loss is in Load flow calculation equation：
Then system head end active power becomes and turns to：
Formula (11) and formula (12) are substituted into formula (9), can finally obtain the terminal voltage variable quantity under end load change condition：
In systems in practice, it is unknown quantity that system head end, which sends out power, can be drawn by end power calculation, calculation formula For：
It is in actual wind power plant direct current delivery system, current conversion station is temporary as the load end in simple mini system, wind turbine Current conversion station busbar pressure differential deltap U in state overvoltage calculation formula (3)cΔ U as in formula (13)2, it is known that current conversion station is sent out initial Active power, reactive power, current conversion station initial voltage, the lower current conversion station active power reactive power variable quantity of direct current disturbance, system Equivalent impedance, current conversion station capacity of short circuit, you can quickly estimate current conversion station busbar pressure difference.
The flow that change of current busbar transient overvoltage quickly calculates when power disturbance occurs for the high-capacity direct current, including it is following Step：
Step 1：According to line drop formula, calculating is tried to achieve between wind-powered electricity generation set end voltage and 750kV main transformer 330kV sides voltage Pressure differential deltap UaAnd the pressure differential deltap U between 750kV transformer 330kV side voltages and 750kV change of current busbar voltagesb；
Step 2：Change of current busbar transient overvoltage quick calculation method after being disturbed according to DC high-power, tries to achieve 750kV and changes Flow the pressure differential deltap U between busbar voltage and system equivalent voltagec；
Step 3：To Δ Ua、ΔUb、ΔUcSummation, is calculated wind-powered electricity generation generator terminal transient overvoltage after DC high-power disturbance Amplitude △ U；
In the step 2, the computational methods are, it is known that the initial active-power P that DC converter station is sent out10With it is idle Power Q10, current conversion station initial voltage U20, the lower current conversion station active power variable quantity △ P of direct current disturbance2With reactive power variable quantity △ Q2, system equivalent impedance R and X, current conversion station capacity of short circuit S, you can quickly estimated according to formula (13) DC high-power disturbance Pressure differential deltap U between 750kV changes of current busbar voltage and system equivalent voltage afterwardsc。
The wind turbine transient overvoltage analysis model, respectively with simple structure mini system model and actual A-I power grids direct current The correctness of method is verified and analyzed exemplified by sending；Wherein, simple mini system model is for this hair of comparative analysis The quick calculation method of bright proposition, the accuracy of Empirical Calculating Method, actual A-I power grid direct currents sending is then to quick meter Calculation method is further analyzed and verified, detailed process is as follows：
(1) simple mini system model：Load side sets active power, reactive power change, takes S*=129.9, system base Standard is 100MVA, R*=0.00025, X*=0.0078,U20=0.9558p.u., sets load side to have Work(is constant, idle change 200MW, 400MW and active power become turn to 200MW, 400MW, 600MW, 800MW, correspondence is idle The design conditions of changed power 100MVA, 200MVA, 300MVA, 400MVA, calculate U respectively2Situation of change；
(2) correctness of method is verified and divided exemplified by actual A-I power grids direct current sending：It is straight with A-I power grids Exemplified by streaming end system, quick calculation method analysis wind power plant transient overvoltage；In A power grid sending structures, AI power grids are straight Near region B stations wind-powered electricity generation, C stations wind-electricity integration are transported to receiving end I power grids by stream；
In A-I power grid direct current transmitting system examples, C stations wind-powered electricity generation online power about 2400MW, B stations wind-powered electricity generation online power is about 2400MW, AI direct current transportation 1400MW, it is idle idle with DC converter station to calculate the lower wind power plant surplus of direct-current commutation failure disturbance Collective effect produces pressure and rises；
It is research busbar by B stations, using looped network as system side, duty value, B stations is used as using B station wind power plants and A current conversion stations S*=163, system benchmark is 100MVA, R*=0.000151, X*=0.006116；
Before DC Line Fault occurs, C-B 750kV double-circuit lines, A-B 750kV double-circuit lines convey active power to system 1000MW, i.e., equivalent burden with power is -1000MW, system is to the i.e. equivalent load or burden without work of B stations conveying reactive power 161MVA 161MVA, B station initial voltage U20=0.98p.u.；Under direct-current commutation failure disturbance failure, B, which stands, and system is active is exchanged for 0, I.e. equivalent burden with power is 0, the B stations idle 1160MVA of surplus, i.e., equivalent load or burden without work is -1160, Δ P2=1000MW, Δ Q2 =-1321MVA；Numerical value is substituted into formula (13) and calculates to obtain Δ Uc=0.077p.u.；
Wind turbine transient overvoltage under direct-current commutation failure is calculated using PSD-BPA electromechanical transient simulations software, with quickly estimating Calculation method is obtained a result contrast, the result is that：
0.077p.u. is upgraded to using quick calculation method current conversion station pressure, actual emulation software calculates wind turbine transient state pressure and is upgraded to 0.1p.u., error 24%；According to Empirical Calculating Method, Δ Uc=0.07p.u., it is 31% that current conversion station pressure, which rises error,；Therefore Quick calculation method error still has 24%.
Advantages of the present invention and beneficial effect are：
The present invention consider load it is active and reactive change cause node voltage change current conversion station transient state pressure rise etc. because Element, from single spur track voltage drop formula, derives the total differential sensitivity formula that node load change causes node voltage to change, The risk of wind turbine transient overvoltage during direct current large disturbances can be effectively assessed, so that traffic control personnel take accordingly in time Prevention corrective action, reduce dc power disturbance for sending end blower voltage stablize influence, for instructing wind turbine reliably to transport Row is of great significance.
The present invention can be used to the risk of wind turbine transient overvoltage during effectively assessment direct current large disturbances, be that wind turbine transient state is steady Determine control measure and offer Technical Reference is provided, main efficacy results are as follows：
(1) wind turbine transient overvoltage analysis model is established.Pass through model analysis, it is indicated that wind field and system pressure difference Δ U master To be made of three parts, and wind turbine transient overvoltage calculation formula is released by line drop formula, it is temporary can effectively to analyze wind turbine State surge characteristic.
(2) a kind of quick analysis calculation method of wind turbine transient overvoltage during direct current large disturbances is proposed.Pass through structure Build single system model, it is proposed that it is a kind of and meanwhile consider load it is active and reactive change cause node voltage change current conversion station it is temporary State pressure rises quick calculation method, and by Experimental comparison, it is preferably accurate to verify that quick calculation method proposed by the present invention has Property and applicability.
With reference to the accompanying drawings and detailed description, the present invention will be further described in detail, but from the present embodiment Limited.
Brief description of the drawings
Fig. 1 is wind turbine transient overvoltage schematic diagram of the present invention；
Fig. 2 is single system model schematic of the present invention；
Fig. 3 is calculation flow chart of the present invention；
Fig. 4 is A-I direct currents delivery system structure diagram of the present invention.
Embodiment
The present invention is wind turbine transient overvoltage analysis method under a kind of high-capacity direct current power disturbance, is comprised the following steps：
Step 1：Wind turbine transient overvoltage analysis model；
Step 2：Change of current busbar transient overvoltage quick calculation method during power disturbance occurs for high-capacity direct current.
The step 1 wind turbine transient overvoltage analysis model.As shown in Figure 1, Fig. 1 is wind turbine transient overvoltage of the present invention point Illustraton of model is analysed, each wind-powered electricity generation is become from 690V boosting 330kV by two-stage boosting, then passes through 330kV connections to 750kV master Become 330kV sides, wind-powered electricity generation reactive-load compensation is in wind field 35kV busbares, if system equivalent voltage E is 1, wind field is for U points with system pressure difference Δ Three parts：ΔUaFor wind-powered electricity generation set end voltage and 750kV main transformer 330kV sides voltage difference, Δ UbFor 750kV transformer 330kV sides with Pressure difference between 750kV busbares, Δ UcFor current conversion station busbar voltage and the pressure liter of system equivalent voltage.It is assumed that under stable situation, system Reactive balance, each several part pressure difference are zero.
System voltage first reduces during commutation failure occurs for direct current, and wind-powered electricity generation enters low voltage crossing state at this time, active Reduction causes the idle surplus of wind field, and certain time, before active power for wind power recovery, during dc power is zero, DC filter is superimposed with the idle surplus of wind turbine makes the idle surplus of wind power direct current transmitting system reach maximum, and overvoltage is most at this time Greatly.Consider most serious operating mode, active power is zero during wind-powered electricity generation low voltage crossing, then wind turbine and system during idle surplus maximum Between pressure difference specifically calculate it is as follows.
According to line drop formulaNegligible resistance obtains：
X in formulaT330For 330kV transformer impedances, QACFor wind power plant 35kV grid entry point reactive-load compensations, XLFor 330kV circuits Impedance, QL1For 330kV line charging power.
X in formulaT750For 750kV transformer reactances, ∑ (QACi+QLi) filled for multiple wind power plant surplus reactive-load compensations and circuit The sum of electrical power, QDFor the reactive-load compensation of 750kV transformers.
Wind turbine transient overvoltage is by between wind-powered electricity generation set end voltage and 750kV main transformer 330kV sides voltage caused by direct current disturbance Pressure difference, the pressure difference between 750kV transformer 330kV side voltages and 750kV change of current busbar voltages, 750kV change of current busbar voltages Pressure difference three parts between system equivalent voltage are formed, as shown in formula (3).
Δ U=Δs Ua+ΔUb+ΔUc(3)；
Δ U in formulaaFor the pressure difference between wind-powered electricity generation set end voltage and 750kV main transformer 330kV sides voltage, Δ UbFor 750kV transformations Pressure difference between device 330kV side voltages and 750kV change of current busbar voltages, Δ UcFor 750kV changes of current busbar voltage and system equivalent Pressure difference between voltage.
Change of current busbar transient overvoltage quick calculation method during power disturbance occurs for step 2 high-capacity direct current, as follows：
Wind power plant surplus is idle under high-capacity direct flow disturbance failure and current conversion station surplus is idle and the active reduction of direct current is common Same-action produces pressure and rises, empirically computational methods, and the rise of DC converter station transient voltage is：
In formula：ΔUcPress and rise for current conversion station busbar transient state；△ Q are idle for wind power plant and current conversion station surplus；S is short for current conversion station Appearance of a street amount；Qc is current conversion station reactive-load compensation filter capacity.
In Empirical Calculating Method, only effect of the consideration idle work variable quantity to system pressure liter, and active change in real system Change also rise pressure and produce certain influence.The present invention is directed to empirical formula deficiency that may be present, and analysis considers negative at the same time The current conversion station transient state pressure that the active and reactive change of lotus causes node voltage to change rises quick calculation method.
As shown in Fig. 2, Fig. 2 is single system illustraton of model of the present invention.In figure, U1For system head end, active power, nothing are sent out Work(power is respectively P1、Q1, U2For load end, active power is sent into, reactive power is respectively P2、Q2, system head end and end It is connected through impedance for R+jX, this impedance is the short-circuit equivalent impedance of change of current busbar.
Load terminal voltage U2With system head end P1、Q1Relation meet power flow equation, wherein it is assumed that U1=1：
R represents system first and last end contact line resistance in formula (5), and X represents the end interconnection reactance of system first and last.
To P1、Q1Differential of demanding perfection obtains：
In formula (6)：D represents differential,
K is the simplification symbol of above-mentioned expression formula.
If load side voltage initial value is U under system initial state20, system send out active power initial value be P10, reactive power Initial value is Q10, Δ P1、ΔQ1Respectively system head end active power, reactive power changing value, then P11=P10+ΔP1Born for end Head end active power after lotus change, Q11=Q10+ΔQ1Head end reactive power after changing for end load.
Make P in formula (5)1=P10、Q1=Q10, draw：
That is K=1/U20, so as to have：
Substitution formula (6) can obtain terminal voltage variation delta U2：
Capacity of short circuitSubstitution formula (8)：
Line loss is in Load flow calculation equation：
Then system head end active power becomes and turns to：
Formula (11) and formula (12) are substituted into formula (9), can finally obtain the terminal voltage variable quantity under end load change condition：
In systems in practice, it is unknown quantity that system head end, which sends out power, can be drawn by end power calculation, calculation formula For：
It is in actual wind power plant direct current delivery system, current conversion station is temporary as the load end in simple mini system, wind turbine Current conversion station busbar pressure differential deltap U in state overvoltage calculation formula (3)cΔ U as in formula (13)2, it is known that current conversion station is sent out initial Active power, reactive power, current conversion station initial voltage, the lower current conversion station active power reactive power variable quantity of direct current disturbance, system Equivalent impedance, current conversion station capacity of short circuit, you can quickly estimate current conversion station busbar pressure difference.
As shown in figure 3, Fig. 3 is calculation flow chart of the present invention.Comprise the following steps：
Step 1：According to line drop formula, calculating is tried to achieve between wind-powered electricity generation set end voltage and 750kV main transformer 330kV sides voltage Pressure differential deltap UaAnd the pressure differential deltap U between 750kV transformer 330kV side voltages and 750kV change of current busbar voltagesb。
Step 2：Change of current busbar transient overvoltage quick calculation method after being disturbed according to DC high-power, tries to achieve 750kV and changes Flow the pressure differential deltap U between busbar voltage and system equivalent voltagec。
Step 3：To Δ Ua、ΔUb、ΔUcSummation, is calculated wind-powered electricity generation generator terminal transient overvoltage after DC high-power disturbance Amplitude △ U.
In the step 2, the computational methods are, it is known that the initial active-power P that DC converter station is sent out10With it is idle Power Q10, current conversion station initial voltage U20, the lower current conversion station active power variable quantity △ P of direct current disturbance2With reactive power variable quantity △ Q2, system equivalent impedance R and X, current conversion station capacity of short circuit S, you can quickly estimated according to formula (13) DC high-power disturbance Pressure differential deltap U between 750kV changes of current busbar voltage and system equivalent voltage afterwardsc。
Embodiment 1：
The present invention is respectively to method by taking the simple mini system model of construction and actual A-I power grid direct current sendings as an example Correctness verified and analyzed.Wherein, simple mini system model is used for comparative analysis quick calculating side proposed by the present invention Method, the accuracy of Empirical Calculating Method, actual A-I power grid direct currents sending is then to quick calculation method proposed by the present invention Further analyze and verify.Detailed process is as follows：
(1) simple mini system analysis.
In the single system model shown in Fig. 2, load side sets active power, reactive power change, this is respectively adopted Invention proposition method, Empirical Calculating Method and PSD-BPA electromechanical transient simulations software calculate Δ U2, contrast moving party of the present invention Method, the accuracy of Empirical Calculating Method.
In simple mini system, S is taken*=129.9 (system benchmark is 100MVA), R*=0.00025, X*=0.0078,U20=0.9558p.u., sets load side active constant, idle change 200MW, 400MW and active Changed power is 200MW, 400MW, 600MW, 800MW, corresponding reactive power change 100MVA, 200MVA, 300MVA, 400MVA Design conditions, U is calculated using proposition method, Empirical Calculating Method and simulation software of the present invention respectively2Situation of change, such as table 1 Shown, table 1 is that the lower transient state pressure of different load change rises.
As it can be seen from table 1 the transient state pressure that formula of the present invention calculates is risen with the numerical value of simulation calculation relatively, and experience The numerical bias of calculating is larger.Under the conditions of four kinds of changed powers, compared with simulation calculation, using the error of Empirical Calculating Method Respectively 14%, 16%, 36%, 38%, 40%, 42%, and be respectively 2.8% using this paper calculation errors, 3.5%, 6%th, 6.2%, 6.6%, 7.2%, institute's extracting method accuracy higher of the present invention.
(2) actual case analysis.
By taking A-I power grid direct current sendings as an example, wind power plant transient state is analyzed using quick calculation method proposed by the present invention Overvoltage.A power grid sending structures are as shown in figure 4, Fig. 4 is A-I direct currents delivery system structure diagram of the present invention.AI power grids Near region B stations wind-powered electricity generation, C stations wind-electricity integration are transported to receiving end I power grids by direct current.
In A-I power grid direct current transmitting system examples, C stations wind-powered electricity generation online power about 2400MW, B stations wind-powered electricity generation online power is about 2400MW, AI direct current transportation 1400MW, it is idle idle with DC converter station to calculate the lower wind power plant surplus of direct-current commutation failure disturbance Collective effect produces pressure and rises.
Be research busbar by B stations using transient overvoltage quick calculation method proposed by the present invention, using looped network in scheming as System side, duty value, B stations S are used as using B station wind power plants and A current conversion stations*=163 (system benchmark is 100MVA), R*= 0.000151, X*=0.006116.
Before DC Line Fault occurs, C-B 750kV double-circuit lines, A-B 750kV double-circuit lines convey active power to system 1000MW (i.e. equivalent burden with power be -1000MW), system are stood to B, and (i.e. equivalence load or burden without work is conveying reactive power 161MVA 161MVA), B stations initial voltage U20=0.98p.u..Under direct-current commutation failure disturbance failure, B, which stands, and system is active is exchanged for 0 (i.e. equivalent burden with power is 0), the idle 1160MVA of B station surpluses (i.e. equivalent load or burden without work is -1160), Δ P2=1000MW, Δ Q2=-1321MVA.Numerical value is substituted into formula (13) and calculates to obtain Δ Uc=0.077p.u..
Wind turbine transient overvoltage under direct-current commutation failure is calculated using PSD-BPA electromechanical transient simulations software, with quickly estimating Calculation method is obtained a result, and contrast is as shown in table 2, and table 2 is the contrast of quick calculation method error.
From table 2 it can be seen that being upgraded to 0.077p.u. using quick calculation method current conversion station pressure, actual emulation software calculates Wind turbine transient state pressure is upgraded to 0.1p.u., error 24%.According to Empirical Calculating Method, Δ Uc=0.07p.u., current conversion station pressure, which rises, to be missed Difference is 31%.Therefore quick calculation method proposed in this paper has more preferable accuracy and applicability.Error still has 24% original In response to being system side equivalence built-in potential because the reason for synchronous generator is encouraged by force in system has raised, prepare in next step to this because Element is modified research.
Table 1：The lower transient state pressure of different load change rises.
Table 2：Quick calculation method error contrasts.

Claims (8)

1. wind turbine transient overvoltage analysis method under a kind of high-capacity direct current power disturbance, it is characterized in that：Comprise the following steps：
Step 1：Wind turbine transient overvoltage analysis model；
Step 2：Change of current busbar transient overvoltage quick calculation method during power disturbance occurs for high-capacity direct current.
2. wind turbine transient overvoltage analysis method under a kind of high-capacity direct current power disturbance according to claim 1, it is special Sign is：The step 1 wind turbine transient overvoltage analysis model, each wind-powered electricity generation by two-stage boosting become from 690V boost 330kV, so Afterwards by 330kV connections to 750kV main transformer 330kV sides, wind-powered electricity generation reactive-load compensation is in wind field 35kV busbares, if system equivalent is electric It is 1 to press E, and U points with system pressure difference Δ of wind field is three parts：ΔUaFor wind-powered electricity generation set end voltage and 750kV main transformer 330kV sides voltage Difference, Δ UbThe pressure difference between 750kV transformer 330kV sides and 750kV busbares, Δ UcFor current conversion station busbar voltage and system equivalent electricity The pressure liter of pressure；It is assumed that under stable situation, System Reactive Power balance, each several part pressure difference is zero.
3. wind turbine transient overvoltage analysis method under a kind of high-capacity direct current power disturbance according to claim 1, it is special Sign is：The direct current, system voltage first reduces during commutation failure occurs, and wind-powered electricity generation enters low voltage crossing state at this time, Active reduction causes the idle surplus of wind field, and certain time, and before active power for wind power recovery, dc power was zero phase Between, DC filter is superimposed with the idle surplus of wind turbine makes the idle surplus of wind power direct current transmitting system reach maximum, excessively electric at this time Pressure is maximum；Consider most serious operating mode, active power is zero during wind-powered electricity generation low voltage crossing, then during idle surplus maximum wind turbine with Pressure difference specifically calculates as follows between system：
According to line drop formulaNegligible resistance obtains：
<mrow> <msub> <mi>&amp;Delta;U</mi> <mi>a</mi> </msub> <mo>&amp;ap;</mo> <msub> <mi>X</mi> <mrow> <mi>T</mi> <mn>330</mn> </mrow> </msub> <msub> <mi>Q</mi> <mrow> <mi>A</mi> <mi>C</mi> </mrow> </msub> <mo>+</mo> <msub> <mi>X</mi> <mi>L</mi> </msub> <mrow> <mo>(</mo> <msub> <mi>Q</mi> <mrow> <mi>A</mi> <mi>C</mi> </mrow> </msub> <mo>+</mo> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> <msub> <mi>Q</mi> <mrow> <mi>L</mi> <mn>1</mn> </mrow> </msub> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>;</mo> </mrow>
X in formulaT330For 330kV transformer impedances, QACFor wind power plant 35kV grid entry point reactive-load compensations, XLFor 330kV line impedances, QL1For 330kV line charging power；
<mrow> <msub> <mi>&amp;Delta;U</mi> <mi>b</mi> </msub> <mo>&amp;ap;</mo> <msub> <mi>X</mi> <mrow> <mi>T</mi> <mn>750</mn> </mrow> </msub> <mo>&amp;lsqb;</mo> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <mrow> <mo>(</mo> <msub> <mi>Q</mi> <mrow> <mi>A</mi> <mi>C</mi> <mi>i</mi> </mrow> </msub> <mo>+</mo> <msub> <mi>Q</mi> <mrow> <mi>L</mi> <mi>i</mi> </mrow> </msub> <mo>)</mo> </mrow> <mo>+</mo> <msub> <mi>Q</mi> <mi>D</mi> </msub> <mo>&amp;rsqb;</mo> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>2</mn> <mo>)</mo> </mrow> <mo>;</mo> </mrow>
X in formulaT750For 750kV transformer reactances, ∑ (QACi+QLi) it is multiple wind power plant surplus reactive-load compensations and line charging work( The sum of rate, QDFor the reactive-load compensation of 750kV transformers.
4. wind turbine transient overvoltage analysis method under a kind of high-capacity direct current power disturbance according to claim 1, it is special Sign is：The wind turbine transient overvoltage is caused by direct current disturbance, by wind-powered electricity generation set end voltage and 750kV main transformer 330kV sides voltage it Between pressure difference, the pressure difference between 750kV transformer 330kV side voltages and 750kV change of current busbar voltages, 750kV changes of current busbar electricity Pressure difference three parts between pressure and system equivalent voltage are formed：
Δ U=Δs Ua+ΔUb+ΔUc(3)；
Δ U in formulaaFor the pressure difference between wind-powered electricity generation set end voltage and 750kV main transformer 330kV sides voltage, Δ UbFor 750kV transformers Pressure difference between 330kV sides voltage and 750kV change of current busbar voltages, Δ UcFor 750kV changes of current busbar voltage and system equivalent electricity Pressure difference between pressure.
5. wind turbine transient overvoltage analysis method under a kind of high-capacity direct current power disturbance according to claim 1, it is special Sign is：Change of current busbar transient overvoltage quick calculation method during power disturbance occurs for step 2 high-capacity direct current, as follows：
Wind power plant surplus is idle under high-capacity direct flow disturbance failure and current conversion station surplus is idle and the active reduction of direct current is made jointly Risen with pressure is produced, empirically computational methods, the rise of DC converter station transient voltage is：
<mrow> <msub> <mi>&amp;Delta;U</mi> <mi>c</mi> </msub> <mo>=</mo> <mfrac> <mrow> <mi>&amp;Delta;</mi> <mi>Q</mi> </mrow> <mrow> <mi>S</mi> <mo>-</mo> <msub> <mi>Q</mi> <mi>c</mi> </msub> </mrow> </mfrac> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>4</mn> <mo>)</mo> </mrow> <mo>;</mo> </mrow>
In formula：ΔUcPress and rise for current conversion station busbar transient state；△ Q are idle for wind power plant and current conversion station surplus；S holds for current conversion station short circuit Amount；Qc is current conversion station reactive-load compensation filter capacity.
6. wind turbine transient overvoltage analysis method under a kind of high-capacity direct current power disturbance according to claim 1, it is special Sign is：The wind turbine transient overvoltage analysis model, wherein, U1For system head end, active power is sent out, reactive power is respectively P1、Q1, U2For load end, active power is sent into, reactive power is respectively P2、Q2, system head end is R+jX through impedance with end It is connected, this impedance is the short-circuit equivalent impedance of change of current busbar；
Load terminal voltage U2With system head end P1、Q1Relation meet power flow equation, wherein it is assumed that U1=1：
<mrow> <msub> <mi>U</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <msub> <mi>P</mi> <mn>1</mn> </msub> <mo>,</mo> <msub> <mi>Q</mi> <mn>1</mn> </msub> <mo>)</mo> </mrow> <mo>=</mo> <msqrt> <mrow> <msup> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>P</mi> <mn>1</mn> </msub> <mi>R</mi> <mo>-</mo> <msub> <mi>Q</mi> <mn>1</mn> </msub> <mi>X</mi> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>+</mo> <msup> <mrow> <mo>(</mo> <msub> <mi>P</mi> <mn>1</mn> </msub> <mi>X</mi> <mo>-</mo> <msub> <mi>Q</mi> <mn>1</mn> </msub> <mi>R</mi> <mo>)</mo> </mrow> <mn>2</mn> </msup> </mrow> </msqrt> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>5</mn> <mo>)</mo> </mrow> <mo>;</mo> </mrow>
R represents system first and last end contact line resistance in formula (5), and X represents the end interconnection reactance of system first and last；
To P1、Q1Differential of demanding perfection obtains：
<mrow> <mtable> <mtr> <mtd> <mrow> <msub> <mi>dU</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <msub> <mi>P</mi> <mn>1</mn> </msub> <mo>,</mo> <msub> <mi>Q</mi> <mn>1</mn> </msub> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mrow> <mo>&amp;part;</mo> <msub> <mi>U</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <msub> <mi>P</mi> <mn>1</mn> </msub> <mo>,</mo> <msub> <mi>Q</mi> <mn>1</mn> </msub> <mo>)</mo> </mrow> </mrow> <mrow> <mo>&amp;part;</mo> <msub> <mi>P</mi> <mn>1</mn> </msub> </mrow> </mfrac> <msub> <mi>dP</mi> <mn>1</mn> </msub> <mo>+</mo> <mfrac> <mrow> <mo>&amp;part;</mo> <msub> <mi>U</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <msub> <mi>P</mi> <mn>1</mn> </msub> <mo>,</mo> <msub> <mi>Q</mi> <mn>1</mn> </msub> <mo>)</mo> </mrow> </mrow> <mrow> <mo>&amp;part;</mo> <msub> <mi>Q</mi> <mn>1</mn> </msub> </mrow> </mfrac> <msub> <mi>dQ</mi> <mn>1</mn> </msub> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>=</mo> <mi>K</mi> <mrow> <mo>(</mo> <mo>-</mo> <mi>R</mi> <mo>+</mo> <msub> <mi>P</mi> <mn>1</mn> </msub> <msup> <mi>R</mi> <mn>2</mn> </msup> <mo>+</mo> <msub> <mi>P</mi> <mn>1</mn> </msub> <msup> <mi>X</mi> <mn>2</mn> </msup> <mo>)</mo> </mrow> <msub> <mi>dP</mi> <mn>1</mn> </msub> <mo>+</mo> <mi>K</mi> <mrow> <mo>(</mo> <mo>-</mo> <mi>X</mi> <mo>+</mo> <msub> <mi>Q</mi> <mn>1</mn> </msub> <msup> <mi>R</mi> <mn>2</mn> </msup> <mo>+</mo> <msub> <mi>Q</mi> <mn>1</mn> </msub> <msup> <mi>X</mi> <mn>2</mn> </msup> <mo>)</mo> </mrow> <msub> <mi>dQ</mi> <mn>1</mn> </msub> </mrow> </mtd> </mtr> </mtable> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>6</mn> <mo>)</mo> </mrow> <mo>;</mo> </mrow>
In formula (6)：D represents differential；
K is the simplification symbol of above-mentioned expression formula：
<mrow> <mi>K</mi> <mo>=</mo> <msup> <mrow> <mo>(</mo> <msup> <mrow> <mo>(</mo> <mrow> <msub> <mi>U</mi> <mn>1</mn> </msub> <mo>-</mo> <mfrac> <mrow> <msub> <mi>P</mi> <mn>1</mn> </msub> <mi>R</mi> <mo>+</mo> <msub> <mi>Q</mi> <mn>1</mn> </msub> <mi>X</mi> </mrow> <msub> <mi>U</mi> <mn>1</mn> </msub> </mfrac> </mrow> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>+</mo> <msup> <mrow> <mo>(</mo> <mfrac> <mrow> <msub> <mi>P</mi> <mn>1</mn> </msub> <mi>X</mi> <mo>-</mo> <msub> <mi>Q</mi> <mn>1</mn> </msub> <mi>R</mi> </mrow> <msub> <mi>U</mi> <mn>1</mn> </msub> </mfrac> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> </msup> </mrow>
If load side voltage initial value is U under system initial state20, system send out active power initial value be P10, reactive power initial value For Q10, Δ P1、ΔQ1Respectively system head end active power, reactive power changing value, then P11=P10+ΔP1Change for end load Head end active power after change, Q11=Q10+ΔQ1Head end reactive power after changing for end load；
Make P in formula (5)1=P10、Q1=Q10, draw：
That is K=1/U20, so as to have：
<mrow> <mtable> <mtr> <mtd> <mrow> <mfrac> <mrow> <mo>&amp;part;</mo> <msub> <mi>U</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <msub> <mi>P</mi> <mn>1</mn> </msub> <mo>,</mo> <msub> <mi>Q</mi> <mn>1</mn> </msub> <mo>)</mo> </mrow> </mrow> <mrow> <mo>&amp;part;</mo> <msub> <mi>P</mi> <mn>1</mn> </msub> </mrow> </mfrac> <mo>=</mo> <mfrac> <mrow> <msub> <mi>P</mi> <mn>10</mn> </msub> <mrow> <mo>(</mo> <msup> <mi>R</mi> <mn>2</mn> </msup> <mo>+</mo> <msup> <mi>X</mi> <mn>2</mn> </msup> <mo>)</mo> </mrow> <mo>-</mo> <mi>R</mi> </mrow> <msub> <mi>U</mi> <mn>20</mn> </msub> </mfrac> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mfrac> <mrow> <mo>&amp;part;</mo> <msub> <mi>U</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <msub> <mi>P</mi> <mn>1</mn> </msub> <mo>,</mo> <msub> <mi>Q</mi> <mn>1</mn> </msub> <mo>)</mo> </mrow> </mrow> <mrow> <mo>&amp;part;</mo> <msub> <mi>Q</mi> <mn>1</mn> </msub> </mrow> </mfrac> <mo>=</mo> <mfrac> <mrow> <msub> <mi>Q</mi> <mn>10</mn> </msub> <mrow> <mo>(</mo> <msup> <mi>R</mi> <mn>2</mn> </msup> <mo>+</mo> <msup> <mi>X</mi> <mn>2</mn> </msup> <mo>)</mo> </mrow> <mo>-</mo> <mi>X</mi> </mrow> <msub> <mi>U</mi> <mn>20</mn> </msub> </mfrac> </mrow> </mtd> </mtr> </mtable> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>7</mn> <mo>)</mo> </mrow> <mo>;</mo> </mrow>
Substitution formula (6) can obtain terminal voltage variation delta U2：
<mrow> <msub> <mi>&amp;Delta;U</mi> <mn>2</mn> </msub> <mo>=</mo> <mfrac> <mrow> <msub> <mi>P</mi> <mn>10</mn> </msub> <mrow> <mo>(</mo> <msup> <mi>R</mi> <mn>2</mn> </msup> <mo>+</mo> <msup> <mi>X</mi> <mn>2</mn> </msup> <mo>)</mo> </mrow> <mo>-</mo> <mi>R</mi> </mrow> <msub> <mi>U</mi> <mn>0</mn> </msub> </mfrac> <msub> <mi>&amp;Delta;P</mi> <mn>1</mn> </msub> <mo>+</mo> <mfrac> <mrow> <msub> <mi>Q</mi> <mn>10</mn> </msub> <mrow> <mo>(</mo> <msup> <mi>R</mi> <mn>2</mn> </msup> <mo>+</mo> <msup> <mi>X</mi> <mn>2</mn> </msup> <mo>)</mo> </mrow> <mo>-</mo> <mi>X</mi> </mrow> <msub> <mi>U</mi> <mn>0</mn> </msub> </mfrac> <msub> <mi>&amp;Delta;Q</mi> <mn>1</mn> </msub> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>8</mn> <mo>)</mo> </mrow> <mo>;</mo> </mrow>
Capacity of short circuitSubstitution formula (8)：
<mrow> <msub> <mi>&amp;Delta;U</mi> <mn>2</mn> </msub> <mo>=</mo> <mfrac> <mn>1</mn> <msub> <mi>U</mi> <mn>20</mn> </msub> </mfrac> <mo>&amp;lsqb;</mo> <mrow> <mo>(</mo> <mfrac> <msub> <mi>P</mi> <mn>10</mn> </msub> <msup> <mi>S</mi> <mn>2</mn> </msup> </mfrac> <mo>-</mo> <mi>R</mi> <mo>)</mo> </mrow> <msub> <mi>&amp;Delta;P</mi> <mn>1</mn> </msub> <mo>+</mo> <mrow> <mo>(</mo> <mfrac> <msub> <mi>Q</mi> <mn>10</mn> </msub> <msup> <mi>S</mi> <mn>2</mn> </msup> </mfrac> <mo>-</mo> <mi>X</mi> <mo>)</mo> </mrow> <msub> <mi>&amp;Delta;Q</mi> <mn>1</mn> </msub> <mo>&amp;rsqb;</mo> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>9</mn> <mo>)</mo> </mrow> <mo>;</mo> </mrow>
Line loss is in Load flow calculation equation：
<mrow> <mtable> <mtr> <mtd> <mrow> <msub> <mi>&amp;Delta;P</mi> <mi>Z</mi> </msub> <mo>+</mo> <msub> <mi>j&amp;Delta;Q</mi> <mi>Z</mi> </msub> <mo>=</mo> <mfrac> <mrow> <msubsup> <mi>P</mi> <mn>2</mn> <mn>2</mn> </msubsup> <mo>+</mo> <msubsup> <mi>Q</mi> <mn>2</mn> <mn>2</mn> </msubsup> </mrow> <msubsup> <mi>U</mi> <mn>1</mn> <mn>2</mn> </msubsup> </mfrac> <mi>R</mi> <mo>+</mo> <mi>j</mi> <mfrac> <mrow> <msubsup> <mi>P</mi> <mn>2</mn> <mn>2</mn> </msubsup> <mo>+</mo> <msubsup> <mi>Q</mi> <mn>2</mn> <mn>2</mn> </msubsup> </mrow> <msubsup> <mi>U</mi> <mn>1</mn> <mn>2</mn> </msubsup> </mfrac> <mi>X</mi> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>=</mo> <mrow> <mo>(</mo> <msubsup> <mi>P</mi> <mn>2</mn> <mn>2</mn> </msubsup> <mo>+</mo> <msubsup> <mi>Q</mi> <mn>2</mn> <mn>2</mn> </msubsup> <mo>)</mo> </mrow> <mi>R</mi> <mo>+</mo> <mi>j</mi> <mrow> <mo>(</mo> <msubsup> <mi>P</mi> <mn>2</mn> <mn>2</mn> </msubsup> <mo>+</mo> <msubsup> <mi>Q</mi> <mn>2</mn> <mn>2</mn> </msubsup> <mo>)</mo> </mrow> <mi>X</mi> </mrow> </mtd> </mtr> </mtable> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>10</mn> <mo>)</mo> </mrow> <mo>;</mo> </mrow>
Then system head end active power becomes and turns to：
<mrow> <mtable> <mtr> <mtd> <mrow> <msub> <mi>&amp;Delta;P</mi> <mn>1</mn> </msub> <mo>=</mo> <msub> <mi>P</mi> <mn>11</mn> </msub> <mo>-</mo> <msub> <mi>P</mi> <mn>10</mn> </msub> <mo>=</mo> <mrow> <mo>(</mo> <msub> <mi>P</mi> <mn>21</mn> </msub> <mo>+</mo> <msub> <mi>&amp;Delta;P</mi> <mrow> <mi>Z</mi> <mn>1</mn> </mrow> </msub> <mo>)</mo> </mrow> <mo>-</mo> <mrow> <mo>(</mo> <msub> <mi>P</mi> <mn>20</mn> </msub> <mo>+</mo> <msub> <mi>&amp;Delta;P</mi> <mrow> <mi>Z</mi> <mn>0</mn> </mrow> </msub> <mo>)</mo> </mrow> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>=</mo> <mrow> <mo>(</mo> <msub> <mi>P</mi> <mn>21</mn> </msub> <mo>-</mo> <msub> <mi>P</mi> <mn>20</mn> </msub> <mo>)</mo> </mrow> <mo>+</mo> <mrow> <mo>(</mo> <msub> <mi>&amp;Delta;P</mi> <mrow> <mi>Z</mi> <mn>1</mn> </mrow> </msub> <mo>-</mo> <msub> <mi>&amp;Delta;P</mi> <mrow> <mi>Z</mi> <mn>0</mn> </mrow> </msub> <mo>)</mo> </mrow> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>=</mo> <msub> <mi>&amp;Delta;P</mi> <mn>2</mn> </msub> <mo>+</mo> <mrow> <mo>(</mo> <msubsup> <mi>P</mi> <mn>21</mn> <mn>2</mn> </msubsup> <mo>+</mo> <msubsup> <mi>Q</mi> <mn>21</mn> <mn>2</mn> </msubsup> <mo>)</mo> </mrow> <mi>R</mi> <mo>-</mo> <mrow> <mo>(</mo> <msubsup> <mi>P</mi> <mn>20</mn> <mn>2</mn> </msubsup> <mo>+</mo> <msubsup> <mi>Q</mi> <mn>20</mn> <mn>2</mn> </msubsup> <mo>)</mo> </mrow> <mi>R</mi> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>&amp;ap;</mo> <msub> <mi>&amp;Delta;P</mi> <mn>2</mn> </msub> </mrow> </mtd> </mtr> </mtable> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>11</mn> <mo>)</mo> </mrow> <mo>;</mo> </mrow>
<mrow> <mtable> <mtr> <mtd> <mrow> <msub> <mi>&amp;Delta;Q</mi> <mn>1</mn> </msub> <mo>=</mo> <msub> <mi>Q</mi> <mn>11</mn> </msub> <mo>-</mo> <msub> <mi>Q</mi> <mn>10</mn> </msub> <mo>=</mo> <mrow> <mo>(</mo> <msub> <mi>Q</mi> <mn>21</mn> </msub> <mo>+</mo> <msub> <mi>&amp;Delta;Q</mi> <mrow> <mi>Z</mi> <mn>1</mn> </mrow> </msub> <mo>)</mo> </mrow> <mo>-</mo> <mrow> <mo>(</mo> <msub> <mi>Q</mi> <mn>20</mn> </msub> <mo>+</mo> <msub> <mi>&amp;Delta;Q</mi> <mrow> <mi>Z</mi> <mn>0</mn> </mrow> </msub> <mo>)</mo> </mrow> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>=</mo> <mrow> <mo>(</mo> <msub> <mi>Q</mi> <mn>21</mn> </msub> <mo>-</mo> <msub> <mi>Q</mi> <mn>20</mn> </msub> <mo>)</mo> </mrow> <mo>+</mo> <mrow> <mo>(</mo> <msub> <mi>&amp;Delta;Q</mi> <mrow> <mi>Z</mi> <mn>1</mn> </mrow> </msub> <mo>-</mo> <msub> <mi>&amp;Delta;Q</mi> <mrow> <mi>Z</mi> <mn>0</mn> </mrow> </msub> <mo>)</mo> </mrow> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>=</mo> <msub> <mi>&amp;Delta;Q</mi> <mn>2</mn> </msub> <mo>+</mo> <mrow> <mo>(</mo> <msubsup> <mi>P</mi> <mn>21</mn> <mn>2</mn> </msubsup> <mo>+</mo> <msubsup> <mi>Q</mi> <mn>21</mn> <mn>2</mn> </msubsup> <mo>)</mo> </mrow> <mi>X</mi> <mo>-</mo> <mrow> <mo>(</mo> <msubsup> <mi>P</mi> <mn>20</mn> <mn>2</mn> </msubsup> <mo>+</mo> <msubsup> <mi>Q</mi> <mn>20</mn> <mn>2</mn> </msubsup> <mo>)</mo> </mrow> <mi>X</mi> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>=</mo> <msub> <mi>&amp;Delta;Q</mi> <mn>2</mn> </msub> <mo>+</mo> <msubsup> <mi>X&amp;Delta;S</mi> <mn>2</mn> <mn>2</mn> </msubsup> </mrow> </mtd> </mtr> </mtable> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>12</mn> <mo>)</mo> </mrow> <mo>;</mo> </mrow>
Formula (11) and formula (12) are substituted into formula (9), can finally obtain the terminal voltage variable quantity under end load change condition：
<mrow> <msub> <mi>&amp;Delta;U</mi> <mn>2</mn> </msub> <mo>=</mo> <mfrac> <mn>1</mn> <msub> <mi>U</mi> <mn>20</mn> </msub> </mfrac> <mo>&amp;lsqb;</mo> <mrow> <mo>(</mo> <mfrac> <msub> <mi>P</mi> <mn>10</mn> </msub> <msup> <mi>S</mi> <mn>2</mn> </msup> </mfrac> <mo>-</mo> <mi>R</mi> <mo>)</mo> </mrow> <msub> <mi>&amp;Delta;P</mi> <mn>2</mn> </msub> <mo>+</mo> <mrow> <mo>(</mo> <mfrac> <msub> <mi>Q</mi> <mn>10</mn> </msub> <msup> <mi>S</mi> <mn>2</mn> </msup> </mfrac> <mo>-</mo> <mi>X</mi> <mo>)</mo> </mrow> <mrow> <mo>(</mo> <msub> <mi>&amp;Delta;Q</mi> <mn>2</mn> </msub> <mo>+</mo> <msubsup> <mi>X&amp;Delta;S</mi> <mn>2</mn> <mn>2</mn> </msubsup> <mo>)</mo> </mrow> <mo>&amp;rsqb;</mo> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>13</mn> <mo>)</mo> </mrow> <mo>;</mo> </mrow>
In systems in practice, it is unknown quantity that system head end, which sends out power, can be drawn by end power calculation, calculation formula is：
<mrow> <msub> <mi>P</mi> <mn>10</mn> </msub> <mo>=</mo> <msub> <mi>P</mi> <mn>20</mn> </msub> <mo>+</mo> <mfrac> <mrow> <msubsup> <mi>P</mi> <mn>20</mn> <mn>2</mn> </msubsup> <mo>+</mo> <msubsup> <mi>Q</mi> <mn>20</mn> <mn>2</mn> </msubsup> </mrow> <msubsup> <mi>U</mi> <mn>20</mn> <mn>2</mn> </msubsup> </mfrac> <mi>R</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>14</mn> <mo>)</mo> </mrow> <mo>;</mo> </mrow>
<mrow> <msub> <mi>Q</mi> <mn>10</mn> </msub> <mo>=</mo> <msub> <mi>Q</mi> <mn>20</mn> </msub> <mo>+</mo> <mfrac> <mrow> <msubsup> <mi>P</mi> <mn>20</mn> <mn>2</mn> </msubsup> <mo>+</mo> <msubsup> <mi>Q</mi> <mn>20</mn> <mn>2</mn> </msubsup> </mrow> <msubsup> <mi>U</mi> <mn>20</mn> <mn>2</mn> </msubsup> </mfrac> <mi>X</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>15</mn> <mo>)</mo> </mrow> <mo>;</mo> </mrow>
In actual wind power plant direct current delivery system, using current conversion station as the load end in simple mini system, wind turbine transient state mistake Current conversion station busbar pressure differential deltap U in voltage computing formula (3)cΔ U as in formula (13)2, it is known that current conversion station is sent out initial active Power, reactive power, current conversion station initial voltage, the lower current conversion station active power reactive power variable quantity of direct current disturbance, system equivalent Impedance, current conversion station capacity of short circuit, you can quickly estimate current conversion station busbar pressure difference.
7. wind turbine transient overvoltage analysis method under a kind of high-capacity direct current power disturbance according to claim 1, it is special Sign is：The flow that change of current busbar transient overvoltage quickly calculates when power disturbance occurs for the high-capacity direct current, including following step Suddenly：
Step 1：According to line drop formula, the pressure tried to achieve between wind-powered electricity generation set end voltage and 750kV main transformer 330kV sides voltage is calculated Poor Δ UaAnd the pressure differential deltap U between 750kV transformer 330kV side voltages and 750kV change of current busbar voltagesb；
Step 2：Change of current busbar transient overvoltage quick calculation method after being disturbed according to DC high-power, tries to achieve 750kV changes of current mother Pressure differential deltap U between line voltage and system equivalent voltagec；
Step 3：To Δ Ua、ΔUb、ΔUcSummation, is calculated wind-powered electricity generation generator terminal transient overvoltage amplitude after DC high-power disturbance △U；
In the step 2, the computational methods are, it is known that the initial active-power P that DC converter station is sent out10And reactive power Q10, current conversion station initial voltage U20, the lower current conversion station active power variable quantity △ P of direct current disturbance2With reactive power variable quantity △ Q2, be Unite equivalent impedance R and X, current conversion station capacity of short circuit S, you can after DC high-power disturbance is quickly estimated according to formula (13) Pressure differential deltap U between 750kV changes of current busbar voltage and system equivalent voltagec。
8. wind turbine transient overvoltage analysis method under a kind of high-capacity direct current power disturbance according to claim 1, it is special Sign is：The wind turbine transient overvoltage analysis model, respectively with simple structure mini system model and actual A-I power grids direct current sending end The correctness of method is verified and analyzed exemplified by system；Wherein, simple mini system model is carried for the comparative analysis present invention The quick calculation method that goes out, the accuracy of Empirical Calculating Method, actual A-I power grid direct currents sending is then to quick calculating side Method is further analyzed and verified, detailed process is as follows：
(1) simple mini system model：Load side sets active power, reactive power change, takes S*=129.9, system benchmark is 100MVA, R*=0.00025, X*=0.0078,=15,=4.1, U20=0.9558p.u., sets load side active Constant, idle change 200MW, 400MW and active power, which become, turns to 200MW, 400MW, 600MW, 800MW, corresponding idle work( Rate changes the design conditions of 100MVA, 200MVA, 300MVA, 400MVA, calculates U respectively2Situation of change；
(2) correctness of method is verified and divided exemplified by actual A-I power grids direct current sending：Sent with A-I power grid direct currents Exemplified by end system, quick calculation method analysis wind power plant transient overvoltage；In A power grid sending structures, AI power grids direct current will Near region B stations wind-powered electricity generation, C stations wind-electricity integration are transported to receiving end I power grids；
In A-I power grid direct current transmitting system examples, C stations wind-powered electricity generation online power about 2400MW, B stations wind-powered electricity generation online power is about 2400MW, AI direct current transportation 1400MW, it is idle idle with DC converter station to calculate the lower wind power plant surplus of direct-current commutation failure disturbance Collective effect produces pressure and rises；
It is research busbar by B stations, using looped network as system side, duty value, B stations S is used as using B station wind power plants and A current conversion stations*= 163, system benchmark is 100MVA, R*=0.000151, X*=0.006116；
Before DC Line Fault occurs, C-B 750kV double-circuit lines, A-B 750kV double-circuit lines convey active power to system 1000MW, i.e., equivalent burden with power is -1000MW, system is to the i.e. equivalent load or burden without work of B stations conveying reactive power 161MVA 161MVA, B station initial voltage U20=0.98p.u.；Under direct-current commutation failure disturbance failure, B, which stands, and system is active is exchanged for 0, I.e. equivalent burden with power is 0, the B stations idle 1160MVA of surplus, i.e., equivalent load or burden without work is -1160, Δ P2=1000MW, Δ Q2 =-1321MVA；Numerical value is substituted into formula (13) and calculates to obtain Δ Uc=0.077p.u.；
Wind turbine transient overvoltage under direct-current commutation failure is calculated using PSD-BPA electromechanical transient simulations software, with quick estimation side Method is obtained a result contrast, the result is that：
0.077p.u. is upgraded to using quick calculation method current conversion station pressure, actual emulation software calculates wind turbine transient state pressure and is upgraded to 0.1p.u., error 24%；According to Empirical Calculating Method, Δ Uc=0.07p.u., it is 31% that current conversion station pressure, which rises error,；Therefore Quick calculation method error still has 24%.
CN201711299262.2A 2017-12-08 2017-12-08 Wind turbine transient overvoltage analysis method under a kind of high-capacity direct current power disturbance Pending CN107968434A (en)

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