CN104833886B - A kind of direct current drop point harmonic wave evaluation method conducted from hiigh pressure stage to low-pressure stage - Google Patents
A kind of direct current drop point harmonic wave evaluation method conducted from hiigh pressure stage to low-pressure stage Download PDFInfo
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- CN104833886B CN104833886B CN201510259464.9A CN201510259464A CN104833886B CN 104833886 B CN104833886 B CN 104833886B CN 201510259464 A CN201510259464 A CN 201510259464A CN 104833886 B CN104833886 B CN 104833886B
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Abstract
The present invention relates to a kind of direct current drop point harmonic wave evaluation method conducted from hiigh pressure stage to low-pressure stage, comprise the following steps：(1) if the position of harmonic wave to be evaluated is located at power network points of common connection, into step (2), if between power network different levels, into step (5)；(2) system harmonic impedance Z is obtainedsWith user's harmonic impedance Zc, Z is flowed to from points of common connectioncHarmonic current(3) willIt is equivalent to inject the harmonic current of points of common connection from user side(4) willValue is compared and evaluated with national standard permissible value；(5) the harmonic wave self-impedance of direct current side gusset is obtainedThe equivalent harmonic wave impedance of load side node linear loadDC side node flows to the harmonic current of load side node linear load(6) willIt is equivalent to the harmonic electric current of load side gusset(7) willValue is compared and evaluated with national standard permissible value.There is provided effective harmonic wave evaluation method for conduction of the present invention to urban distribution network direct current drop point harmonic wave from hiigh pressure stage to low-pressure stage.
Description
Technical field
The present invention relates to mains by harmonics evaluation method, fall more particularly, to a kind of direct current conducted from hiigh pressure stage to low-pressure stage
Point harmonic wave evaluation method.
Background technology
Harm can be produced to electrical equipment by occurring harmonic voltage and electric current in power system, cause apparatus overheat, insulation
Aging, causes the decay of transmission energy, the reduction of power factor, and therefore, harmonic problem is always taken seriously.With power electronics
Element largely using in power system, they bring even more serious and multiple after the quality of power supply is improved, also to system
Miscellaneous harmonic problem.
China's energy circulation it is big, under remote actual conditions, country is just embarking powerful UHV transmission
Network.Transferring electricity from the west to the east, north and south supply mutually, national network, it is a wide range of in resource-sharing and the requirement distributed rationally to electric utility
New test is proposed, high voltage dc transmission technology arises at the historic moment.The current converter that D.C. high voltage transmission is used is typical non-thread
Property electronic installation, the alternating current-direct current side that it can become in electric energy transmitting procedure in the change of current produces various harmonic waves.
For the urban distribution network of the drop point containing direct current, nonlinear-load of the harmonic wave conduction with amphicheirality, i.e. undervoltage level is produced
Raw harmonic wave to voltage level spread while, the direct current drop point harmonic wave of voltage level can also conduct to undervoltage level.It is a large amount of real
As shown by data is surveyed, direct current drop point harmonic wave accounts for leading in urban distribution network harmonic propagation.
For this new problem, first, straight interacted system access makes urban distribution network harmonic wave have from voltage levels to low
Voltage class conduction feature step by step, this harmonic wave for being diffused into voltage level with undervoltage level takes on a different character.However, existing
Harmonic analysis method, including harmonic wave national standard appraisement system, typically for harmonic wave in traditional power network from undervoltage level to high electricity
Arbitrarily downgrade what diffusion was proposed.By taking utility network harmonic wave GB/T 14549-1993 standards as an example, the standard specifies utility network harmonic wave
Harmonic voltage limit and injection points of common connection allowable harmonic current, the definition of harmonic source is only limitted to public affairs in standard
Common-battery net harmonic electric current or the electric equipment that harmonic voltage is produced in public electric wire net, in the harmonic wave of regulation points of common connection
When electric current permissible value and distribution principle, also just for the user-side harmonic source of points of common connection, system side harmonic source is not directed to, it is whole
The scope of application of individual standard is limited to the situation that traditional mains by harmonics spreads from undervoltage level to voltage level.If still directly adopted
The harmonic current size of direct current drop point generation is evaluated with the allowable harmonic current under national standard framework, because standard is for using
What family side harmonic source was formulated, and direct current drop point harmonic wave belongs to system side, both concepts are different, and this evaluation will lose meaning, mesh
Before lack it is a kind of be applied to direct current drop point harmonic wave from voltage level to the analysis of undervoltage level conductive process and evaluation method.
Furthermore, direct current drop point harmonic wave meets harmonic wave national standard after device suppresses in public interface after filtering, but by electricity
Web frame influences, and especially the inductant-capacitance coupling of cable and overhead line direct-to-ground capacitance in power network easily causes higher hamonic wave amplification,
So as to influence harmonic wave conductive process, cause harmonic excess.
Therefore, find a kind of urban distribution network direct current drop point harmonic wave from voltage level to the analysis of undervoltage level transport properties and
Evaluation method is necessary.
The content of the invention
The purpose of the present invention is exactly the defect in order to overcome prior art presence and provides one kind to from hiigh pressure stage to low pressure
The direct current drop point harmonic wave of level conduction carries out the method effectively analyzed and evaluated, and voltage level is injected to the harmonic current of undervoltage level
Be converted to the harmonic current that undervoltage level under harmonic wave national standard framework injects voltage level by the principle of equal effects, and with national standard harmonic current
Permissible value compares, to evaluate its influence degree.
The purpose of the present invention can be achieved through the following technical solutions：
A kind of direct current drop point harmonic wave evaluation method conducted from hiigh pressure stage to low-pressure stage, comprises the following steps：
(1) judge the position of harmonic wave to be evaluated, if the position of harmonic wave to be evaluated is located at power network points of common connection, enter step
Suddenly (2), if being located between power network different levels, into step (5)；
(2) computing system harmonic impedance ZsWith user's harmonic impedance Zc, measure and flow to Z from points of common connectioncHarmonic current
(3), will to produce identical harmonic voltage as equivalent conditionIt is equivalent to inject the humorous of points of common connection from user side
Ripple electric current
(4) willValue is compared with this national standard Injection Current permissible value, is obtained evaluation result, is exited；
(5) the harmonic wave self-impedance of direct current side gusset is calculatedThe linear load of load side gusset resistsMeasure DC side
The harmonic source of node flows to the electric current of the linear load of load side gussetWherein, h is the number of times of harmonic wave to be evaluated；
(6), will to produce identical harmonic voltage as equivalent conditionIt is equivalent to the harmonic electric current of load side gusset
(7) willValue is compared with this national standard Injection Current permissible value, is obtained evaluation result, is exited.
It is describedWithMeasuring method is：Harmonic analysis instrument is sealed in branch road to measure.
The system harmonic impedance ZsWith user's harmonic impedance ZcCalculated and obtained by mains by harmonics parametric technique.
The system harmonic impedance ZsCalculating in eliminate the effect of wave filter.
The harmonic wave self-impedance of the direct current side gussetThe linear load of load side gusset resistsJoined by mains by harmonics
Counting method, which is calculated, to be obtained.
Compared with prior art, the present invention has the following effects that and advantage：
(1) process conducted for urban distribution network direct current drop point harmonic wave from voltage level to undervoltage level, by voltage level
Harmonic current equivalence is the harmonic electric current of undervoltage level, compensate for the blank parts during international harmonic current is provided.
(2) two kinds of situations respectively with regard to harmonic wave when same common connecting point and different voltage class conduct, give humorous
The equivalency transform method of ripple electric current, the harmonic wave conduction for certain point in the urban distribution network of drop point containing direct current or certain region can be provided
Corresponding analysis method, with extensive adaptability.
(3) voltage level harmonic electric current is limited in standard allowed band, it is to avoid mains by harmonics hazards.
(4) measurement and computational methods are simple, easily realize, with higher engineering use value.
Brief description of the drawings
Fig. 1 is system side and user side equivalent circuit diagram；
Fig. 2 is harmonic propagation illustraton of model between different levels network；
Fig. 3 is certain city partial electric grid computation model figure；
Fig. 4 is that 11 each branch road harmonic currents, equivalent Injection Current and national standard Injection Current permissible value compare figure；
Fig. 5 is that 13 each branch road harmonic currents, equivalent Injection Current and national standard Injection Current permissible value compare figure；
Fig. 6 is the flow chart of the inventive method.
Embodiment
The present invention is described in detail with specific embodiment below in conjunction with the accompanying drawings.The present embodiment is with technical solution of the present invention
Premised on implemented, give detailed embodiment and specific operating process, but protection scope of the present invention is not limited to
Following embodiments.
Embodiment
As shown in fig. 6, the present embodiment provides a kind of direct current drop point harmonic wave evaluation method conducted from hiigh pressure stage to low-pressure stage,
Concretely comprise the following steps：
S1, judges the position of harmonic wave to be evaluated, if positioned at power network points of common connection, into step (2), if positioned at power network
Between different levels, then into step S5；
S2, utilizes mains by harmonics parametric technique computing system harmonic impedance ZsWith user's harmonic impedance Zc, wherein ZsCalculating
In eliminate the effect of wave filter；Harmonic analysis instrument is sealed in user's branch road, measurement flows to Z from points of common connectioncHarmonic wave
Electric current
S3, will to produce identical harmonic voltage as equivalent conditionIt is equivalent to inject the humorous of points of common connection from user side
Ripple electric current
S4, willValue is compared with this national standard Injection Current permissible value, and evaluates its influence degree, is obtained and is evaluated knot
Really, exit.
S5, calculates the harmonic wave self-impedance of DC side node iLoad side gusset j linear load equivalent harmonic wave impedanceHarmonic analysis instrument is sealed in branch road, measuring node i harmonic source flows to the electric current of j linear loadWherein, h is
The number of times of harmonic wave to be evaluated；
S6, will to produce identical harmonic voltage as equivalent conditionIt is equivalent to node j harmonic electric current
S7, willValue is compared with this national standard Injection Current permissible value, and evaluates its influence degree, is obtained and is evaluated knot
Really, exit.
It is right belowWithComputational methods describe in detail：
As shown in figure 1, when harmonic wave conducts in same common connecting point, if harmonic voltageIt is system side harmonic source
The result of independent role, user's harmonic impedance Z is flowed in common connecting pointcHarmonic current beI.e.
Similarly, if harmonic voltageIt is user-side harmonic sourceThe result of independent role, system is flowed in common connecting point
Harmonic impedance ZsHarmonic current beI.e.
Because | Zc| ＞ ＞ | Zs|, i.e., user's harmonic impedance amplitude is much larger than system harmonic impedance amplitude, so producing same
The harmonic voltage of size, i.e. Vo1=Vo2When, system side injects public interface harmonic currentInject public much smaller than user side
Interface harmonic currentIn order to there is an evaluation criteria of equal value to both sides Injection Current under harmonic wave national standard framework, by system
The harmonic current that public interface harmonic current is equivalent to inject as the following formula points of common connection from user side is injected in side：
Calculated according to this formulaWithWith same effect, directly it can be weighed with national standard Injection Current permissible value
Its influence degree.
As shown in Fig. 2 when harmonic wave is propagated in power network different levels, with the non-of the DC side harmonics source of node i and node j
Linear load harmonic source is illustrated exemplified by node j effect, first, and the humorous of h subharmonic is set up according to harmonic propagation model
Wave impedance equation is：
Wherein,It is node i and node j h harmonic electric current respectively；Be byJointly
Effect, the h subharmonic voltages produced respectively in node i and node j；Represent respectively h times of node i and node j it is humorous
Ripple self-impedance；Represent respectively between node j and i, the h subharmonic mutual impedance between node i and j.
From above formula, whenIndependent role is in node j, the harmonic voltage of generationFor：
WhenIndependent role is in node j, the harmonic voltage of generationFor：
WhenWithWhen equal：
Therefore, can be by the DC side harmonics source of node iIt is equivalent to
Calculated according to this formulaWithWith same effect, butCan not direct measurement；
The electric current of the actual linear load for flowing to node j in DC side harmonics sourceFor：
In formula：It is the equivalent harmonic wave impedance of node j linear load.
Under normal circumstances,So Direct measurement it can arrive at the scene.Then produce false
As：WhenDuring less than harmonic wave national standard permissible value, it is believed that harmonic current is qualified.Therefore, in order to right under harmonic wave national standard framework
Both sides Injection Current has an evaluation criteria of equal value, the harmonic current of measurement should following formula carry out equivalent transformation, be only national standard meaning
Injected value of current under justice：
By such conversion, measurement can be passed throughTo obtain the equivalent harmonic wave that points of common connection is injected from user side
Electric current, then directly weighs its influence degree with national standard Injection Current permissible value.
As shown in figure 3, the harmonic current of each branch road harmonic wave of 11 times, 13 times in certain actual city partial electric grid is live
Measured value and calculated value are compared respectively, as a result as shown in table 1：
The branch road harmonic current of table 1
For branch road harmonic current data, Fig. 4, Fig. 5 respectively illustrate the harmonic current, equivalent of 11 times, 13 times each branch roads
Injection Current and national standard Injection Current permissible value compare.As can be seen that evaluating straight by the allowable harmonic current under national standard framework
The branch road harmonic current size that fall point harmonic wave is produced is nonsensical, because both concepts are different.Note under national standard framework
Enter harmonic current to refer to flow to system side from load side, and the harmonic wave of direct current drop point is to flow to load side from system side, Liang Zhetong
The harmonic voltage that sample size is produced is different, obtains equivalent Injection Current as conversion by the present invention, just has comparativity with national standard.Tool
Body, do not use the present invention to make equivalent transformation to harmonic current if can be seen that from Fig. 4, Fig. 5, remaining each branch road in addition to line 1
11 times, 13 subharmonic currents be significantly less than correspondence bus national standard allowable harmonic current, overall judged result is direct current
The branch road harmonic current that drop point is produced is not serious.However, making to harmonic current after equivalent transformation, equivalent harmonic electric current is about
It is more than 7 times of correspondence branch road harmonic current, except becoming 11 times of 3 remaining outer each branch road, 13 subharmonic currents have exceeded and correspond to
The national standard allowable harmonic current of bus, evaluation result illustrates that direct current drop point harmonic wave brings serious harmonic problem.To sum up divide
Analysis understands that the present invention is applied to direct current drop point harmonic wave from voltage level to the analysis of undervoltage level conductive process.
Claims (5)
1. a kind of direct current drop point harmonic wave evaluation method conducted from hiigh pressure stage to low-pressure stage, it is characterised in that comprise the following steps：
(1) position of harmonic wave to be evaluated is judged, if the position of harmonic wave to be evaluated is located at power network points of common connection, into step
(2), if being located between power network different levels, into step (5)；
(2) computing system harmonic impedance ZsWith user's harmonic impedance Zc, measure and flow to Z from points of common connectioncHarmonic current
(3), will to produce identical harmonic voltage as equivalent conditionIt is equivalent to inject the harmonic wave electricity of points of common connection from user side
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(4) willValue is compared with this national standard Injection Current permissible value, is obtained evaluation result, is exited；
(5) the harmonic wave self-impedance of direct current side gusset is calculatedThe linear load impedance of load side gussetMeasure DC side section
The harmonic source of point flows to the electric current of the linear load of load side gussetWherein, h is the number of times of harmonic wave to be evaluated；
(6), will to produce identical harmonic voltage as equivalent conditionIt is equivalent to the harmonic electric current of load side gusset
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(7) willValue is compared with this national standard Injection Current permissible value, is obtained evaluation result, is exited.
2. a kind of direct current drop point harmonic wave evaluation method conducted from hiigh pressure stage to low-pressure stage according to claim 1, it is special
Levy and be, it is describedWithMeasuring method is：Harmonic analysis instrument is sealed in branch road to measure.
3. a kind of direct current drop point harmonic wave evaluation method conducted from hiigh pressure stage to low-pressure stage according to claim 1, it is special
Levy and be, the system harmonic impedance ZsWith user's harmonic impedance ZcCalculated and obtained by mains by harmonics parametric technique.
4. a kind of direct current drop point harmonic wave evaluation method conducted from hiigh pressure stage to low-pressure stage according to claim 1, it is special
Levy and be, the system harmonic impedance ZsCalculating in eliminate the effect of wave filter.
5. a kind of direct current drop point harmonic wave evaluation method conducted from hiigh pressure stage to low-pressure stage according to claim 1, it is special
Levy and be, the harmonic wave self-impedance of the direct current side gussetThe linear load impedance of load side gussetJoined by mains by harmonics
Counting method, which is calculated, to be obtained.
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| CN109617111A (en) * | 2018-12-14 | 2019-04-12 | 华南理工大学 | The method for measuring multi-infeed HVDC system Inverter Station exchange side harmonic wave interaction intensity |
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| CN102522750A (en) * | 2011-11-29 | 2012-06-27 | 华北电力大学 | Calculating method of user permitted harmonic current emission limits for separating background harmonic |
| CN103344828A (en) * | 2013-07-12 | 2013-10-09 | 重庆大学 | Novel harmonic emission level assessment method |
| CN103364618A (en) * | 2013-07-26 | 2013-10-23 | 武汉大学 | Measuring method for harmonic voltage on direct current side of high-voltage direct current power transmission system |
| CN103675446A (en) * | 2013-12-23 | 2014-03-26 | 重庆大学 | Real-time accurate harmonic source positioning system and method |
| CN103838959A (en) * | 2013-12-18 | 2014-06-04 | 国网上海市电力公司 | Method for applying partial least squares regression to power distribution network harmonic source positioning and detecting |
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| JP4344763B2 (en) * | 2007-09-03 | 2009-10-14 | 本田技研工業株式会社 | Active vibration and noise control device for vehicle |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102522750A (en) * | 2011-11-29 | 2012-06-27 | 华北电力大学 | Calculating method of user permitted harmonic current emission limits for separating background harmonic |
| CN103344828A (en) * | 2013-07-12 | 2013-10-09 | 重庆大学 | Novel harmonic emission level assessment method |
| CN103364618A (en) * | 2013-07-26 | 2013-10-23 | 武汉大学 | Measuring method for harmonic voltage on direct current side of high-voltage direct current power transmission system |
| CN103838959A (en) * | 2013-12-18 | 2014-06-04 | 国网上海市电力公司 | Method for applying partial least squares regression to power distribution network harmonic source positioning and detecting |
| CN103675446A (en) * | 2013-12-23 | 2014-03-26 | 重庆大学 | Real-time accurate harmonic source positioning system and method |
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