CN104376174B - Alternating current line parameter identification and correction method based on line impedance ratio - Google Patents
Alternating current line parameter identification and correction method based on line impedance ratio Download PDFInfo
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- CN104376174B CN104376174B CN201410662866.9A CN201410662866A CN104376174B CN 104376174 B CN104376174 B CN 104376174B CN 201410662866 A CN201410662866 A CN 201410662866A CN 104376174 B CN104376174 B CN 104376174B
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Abstract
The invention relates to an alternating current line parameter identification and correction method based on a line impedance ratio. The method includes the following steps that (1) the alternating line information is extracted; (2) the specific value between the actual resistance and reactance of an alternating line is calculated; (3) the standard resistance, reactance, conductance and susceptance value of the line of the model in unit length are searched for in a line standard parameter database; (4) whether the alternating current line length information is contained in an input file or not is judged; (5) the standard value of an alternating line parameter is compared with the actual value, if the compared value does not exceed the warning threshold value, the parameter is reasonable, and identification is ended; (6) the estimated standard value of the alternating line parameter and the standard value changing range are checked, if the estimated standard value is within the maximum value and the minimum value of the standard value changing range, the parameter is reasonable, and identification is ended; (7) the information related to the data identified to be false or unreasonable is output. The alternating current line parameter identification and correction method based on the line impedance ratio can be widely applied to alternating line parameter identification and correction in large-scale power grid planning.
Description
Technical field
The present invention relates to a kind of alternating current circuit parameter identification and modification method, line impedance ratio is based on especially with regard to one kind
Alternating current circuit parameter identification and modification method.
Background technology
With the fast development of China's economy, power network scale is also being expanded rapidly, due to the limitation of information tool, big rule
On the one hand the power network of mould increases the possibility that planning personnel fills out wrong data, and the debugging of another aspect discharge misses data and brings greatly
Inconvenience, this also result in actual mechanical process, and planning personnel obviously knows that there may be data fills in mistake, but suffers from not
There is the such large-scale data method of identification and feel simply helpless.
In China, BPA power system computation analysis softwares are widely used a software during Power System Planning,
With convergence it is good, calculating speed is fast many advantages, such as.However, planning personnel uses the process of BPA in practical operation at this stage
In, because BPA lacks flexibly practical man-machine interaction instrument, its Load flow calculation data mainly fills in completion by manual entry, and
And the BPA data of same planning power network need different people to fill in respectively could to complete, may have among these it is prefecture-level, provincial,
The Electric Power Network Planning personnel such as region class, because the consummation such as technology, business degree has larger difference, often lead to BPA data and are adopting
Collection obtains, fills in and inevitably produce wrong or irrational data during typing, edit-modify etc..Further, since BPA
There is many special data form limitations in software, such as each single item of each data card has special data long in BPA in itself
Degree and data accuracy specifications, yet with being familiar with for different users of service and the degree of understanding, fill in the presence of the aspects such as customary way
Larger difference, often leading to different personnel can produce the different phenomenon of computational accuracy when identical data is filled in.
Wrong or unreasonable data caused by above mentioned problem can produce larger to the Load flow calculation convergence and result of BPA
Influence.First, mistake and unreasonable data can influence the convergence of Load flow calculation, and the work for increasing planning personnel's adjustment trend is born
Load；Secondly, mistake and unreasonable data can influence the accuracy of calculation of tidal current, may cause Electric Power Network Planning result and reality
Result error farther out, causes larger economic waste, may be hidden some dangers for power grid security what is more.Therefore, practical, flexible,
The identification and modification method for efficiently realizing wrong and unreasonable data in large scale electric network planning have important effect and reality
Trample value.
The content of the invention
Regarding to the issue above, can efficiently realize that large scale electric network is wrong in planning comprehensively it is an object of the invention to provide one kind
By mistake and unreasonable data identification and amendment based on line impedance than alternating current circuit parameter identification and modification method.
To achieve the above object, the present invention takes following technical scheme：It is a kind of based on line impedance than alternating current circuit join
Number identification and modification method, comprise the following steps：1) alternating current circuit for Load flow calculation is extracted in existing BPA dat files
Information；2) calculation procedure 1) in actual resistance and the reactance ratio of all alternating current circuits that extract；3) judge step 1) in carry
Whether contain alternating current circuit type information in the alternating current circuit information for taking, if it has, then directly using the alternating current circuit type for containing
Number information searches measuring resistance, reactance, conductance and the susceptance value of the model circuit unit length in line standard parameter library；Instead
It, then according to step 2) in standard electric in actual resistance and the reactance ratio of alternating current circuit that calculate and line standard parameter library
Resistance is compared with reactance ratio, determines circuit model, and search according in the online road standard parameter library of circuit model for determining
The measuring resistance of the model circuit unit length, reactance, conductance and susceptance value；4) step 1 is judged) the middle alternating current circuit letter for extracting
Whether contain alternating current circuit length information in breath, if it has, then according to alternating current circuit length information and step 3) in online road sign
The standard parameter value of the model circuit unit length found in quasi- parameter library is calculated the standard of the alternating current circuit parameter
Value, into step 5)；Conversely, regression model is set up using the incidence relation between different line parameter circuit values, according to the recurrence set up
Model estimated the length of alternating current circuit, then further according to the alternating current circuit length and step 3 of estimation) in line standard
The standard parameter value of the model circuit unit length found in parameter library is calculated the estimation mark of the alternating current circuit parameter
Quasi- value, into step 6)；5) by step 4) obtained in alternating current circuit parameter standard value and the alternating current circuit parameter reality
Actual value is contrasted, and judges whether the standard value of the alternating current circuit parameter exceedes early warning threshold set in advance with the deviation of actual value
Angle value, if being not above early warning threshold angle value, the alternating current circuit parameter is filled in rationally, terminates parameter identification；Conversely, then should
The actual value of alternating current circuit parameter labeled as wrong or unreasonable data, and by step 4) obtained in the alternating current circuit parameter
Standard value as recommend modified values, while providing the standard value excursion of all such parameters of the model alternating current circuit
As the term of reference for manually correcting adjustment again, into step 7)；6) by step 4) obtained in alternating current circuit parameter estimate
Calculate standard value to be tested with the standard value excursion of all such parameters of the model alternating current circuit, if the alternating current circuit
Maximum and minimum of the standard of appraisal value of parameter in the standard value excursion of all such parameters of the model alternating current circuit
Between value, then the alternating current circuit parameter is filled in rationally, terminates parameter identification；Conversely, being considered as unreasonable, and corresponding maximum is used
Or minimum value is substituted, and mark instead identification, confirm during adjustment for manually being changed again, into step 7)；7) output identification
It is the relevant information of wrong or unreasonable data.
The step 4) in, regression model is set up using the incidence relation between different line parameter circuit values, according to regression model pair
The length of alternating current circuit is estimated that it is comprised the following steps：1. historical data base is created：Historical data is in BPA dat files
Complete and reasonably alternating current circuit parameter, line length and circuit types are filled in middle extraction；2. regression equation is set up as follows：
La=ALr+BLx+CLb+D (1)
In formula, LaIt is the estimate of alternating current circuit length；LrIt is the resistance value filled in historical data divided by unit length mark
The line length that quasi- resistance value is calculated；LxIt is the reactance value filled in historical data divided by unit length standard inductance value meter
The line length for obtaining；LbFor the line that the susceptance value filled in historical data is calculated divided by unit length normalized susceptance value
Road length；LwIt is the alternating current circuit length value filled in historical data；A, B, C, D are respectively coefficient value to be tried to achieve；For residual error is flat
Fang He；N is the number of sample data in historical data；3. regression equation is solved：Historical data, root are read from historical data base
According to the set of coefficient value A, B, C, D to be tried to achieve in historical data solution formula (1), least square method is utilized according to formula (2),
Finding makes residual sum of squares (RSS)It is the value of A, B, C, D of minimum value, determines formula (1)；4. alternating current circuit length is estimated：Root first
According to step 1) in alternating current circuit information and step 3) in the measuring resistance of unit length, reactance and the susceptance value that find calculate
Lr、LxAnd LbValue, the value that will be calculated substitutes into the formula (1) 3. determined by step, is calculated the estimate of line length
La。
Due to taking above technical scheme, it has advantages below to the present invention：1st, the present invention is due to using computer software
System has inerrancy or the identification of unreasonable supplemental characteristic in being automatically obtained the Load flow calculation data of BPA, drastically increases rule
The operating efficiency of the personnel of drawing, it is ensured that the accuracy of Electric Power Network Planning data and the reliability of result of calculation.2nd, the present invention is due to using
The standard value of alternating current circuit parameter is contrasted with actual value, therefore not only can exactly judge that the alternating current circuit parameter is filled in
It is whether correct, the information such as suggestion modified values and canonical parameter excursion can also be given, be capable of achieving in alternating current circuit mistake and
The automatic identification of unreasonable parameter and amendment.In sum, the present invention can be widely applied to the friendship in large scale electric network planning
Flow Line parameter identification and modification.
Brief description of the drawings
Fig. 1 be it is of the invention based on line impedance than alternating current circuit parameter identification and modification method flow chart
Specific embodiment
The present invention is described in detail with reference to the accompanying drawings and examples.
As shown in figure 1, the present invention provide it is a kind of based on line impedance than alternating current circuit parameter identification and modification method, bag
Include following steps：
1) information of the alternating current circuit for Load flow calculation is extracted in existing BPA dat files.
2) calculation procedure 1) in the practical impedance ratio (resistance with reactance ratio) of all alternating current circuits that extracts.
3) judge step 1) in the alternating current circuit information extracted whether containing alternating current circuit type information, if it has, then
The standard of the model circuit unit length is directly searched in line standard parameter library using the alternating current circuit type information for containing
The parameter informations such as resistance, reactance, conductance and susceptance value；If it is not, according to step 2) in calculate alternating current circuit reality
Impedance ratio is compared with the normal impedance ratio in line standard parameter library, so that it is determined that circuit model, and according to the line for determining
Road model searches measuring resistance, reactance, conductance and susceptance value of the model circuit unit length etc. in line standard parameter library
Parameter information.
4) judge step 1) in the alternating current circuit information extracted whether containing alternating current circuit length information, if it has, then
According to alternating current circuit length information and step 3) in the model circuit unit length that is found in line standard parameter library
Standard parameter value is calculated the standard value of the alternating current circuit parameter, into step 5)；If it is not, needing using not collinear
Incidence relation between the parameter of road sets up regression model, and the length of alternating current circuit is estimated according to the regression model set up,
Then further according to alternating current circuit length and the step 3 of estimation) in the model circuit list that is found in line standard parameter library
The standard parameter value of bit length is calculated the standard of appraisal value of the alternating current circuit parameter, into step 6)；
Using the incidence relation between different line parameter circuit values set up regression model (such as regression analysis model, neural network model,
Supporting vector machine model etc.), the length of alternating current circuit is estimated according to regression model, herein only with multiple regression analysis method
As a example by carry out calculating analysis, it is comprised the following steps：
1. historical data base is created：Historical data be extracted in BPA dat files fill in complete and reasonably exchange
The data such as line parameter circuit value, line length and circuit types.
2. regression equation is set up as follows：
La=ALr+BLx+CLb+D (1)
In formula, LaIt is the estimate of alternating current circuit length；LrIt is the resistance value filled in historical data divided by unit length mark
The line length that quasi- resistance value is calculated；LxIt is the reactance value filled in historical data divided by unit length standard inductance value meter
The line length for obtaining；LbFor the line that the susceptance value filled in historical data is calculated divided by unit length normalized susceptance value
Road length；LwIt is the alternating current circuit length value filled in historical data；A, B, C, D are respectively coefficient value to be tried to achieve；For residual error is flat
Fang He；N is the number of sample data in historical data.
3. regression equation is solved：Historical data is read from historical data base, according in historical data solution formula (1)
The set of coefficient value A, B, C, D to be tried to achieve, being found using least square method according to formula (2) makes residual sum of squares (RSS)It is minimum value
A, B, C, D value, determine formula (1)；
4. alternating current circuit length is estimated：First according to step 1) in alternating current circuit information and step 3) in the list that finds
The measuring resistance of bit length, reactance and susceptance value calculate Lr、LxAnd LbValue, the value that will be calculated substitutes into and 3. determined by step
Formula (1), be calculated the estimate L of line lengtha；
5) by step 4) obtained in the standard value of alternating current circuit parameter carried out with the actual value of the alternating current circuit parameter
Contrast, judges whether the standard value of the alternating current circuit parameter exceedes early warning threshold angle value set in advance with the deviation of actual value, such as
Fruit is not above early warning threshold angle value, then the alternating current circuit parameter is filled in rationally, terminates parameter identification；If it exceeds early warning threshold degree
Value, then by the actual value of the alternating current circuit parameter labeled as wrong or unreasonable data, and by step 4) obtained in the friendship
The standard value of Flow Line parameter as recommend modified values, while providing the standard of all such parameters of the model alternating current circuit
Value changes scope as the term of reference for manually correcting adjustment again, into step 7).
6) by step 4) obtained in all of standard of appraisal value and the model alternating current circuit of alternating current circuit parameter should
The standard value excursion of class parameter is tested, if the standard of appraisal value of the alternating current circuit parameter is in the model alternating current circuit
All such parameters standard value excursion maximum and minimum value between, then the alternating current circuit parameter is filled in rationally,
Terminate parameter identification；Otherwise, it is considered as unreasonable, and is substituted with corresponding maximum or minimum value, and mark instead identification,
Confirm during adjustment for manually being changed again, into step 7).
7) output identification is the relevant information of wrong or unreasonable data, such as line name, numbering, parameter name, parameter
Classification, actual value, suggestion modified values, mistake or unreasonable reason, length estimated value, standard parameter value etc..
The various embodiments described above are merely to illustrate the present invention, wherein the structure of each part, connected mode and manufacture craft etc. are all
Can be what is be varied from, every equivalents carried out on the basis of technical solution of the present invention and improvement should not be excluded
Outside protection scope of the present invention.
Claims (1)
1. it is a kind of based on line impedance than alternating current circuit parameter identification and modification method, comprise the following steps：
1) information of the alternating current circuit for Load flow calculation is extracted in existing BPA dat files；
2) calculation procedure 1) in actual resistance and the reactance ratio of all alternating current circuits that extract；
3) judge step 1) in the alternating current circuit information extracted whether containing alternating current circuit type information, if it has, then direct
Using the alternating current circuit type information for containing searched in line standard parameter library the model circuit unit length measuring resistance,
Reactance, conductance and susceptance value；Conversely, then according to step 2) in actual resistance and reactance ratio and the circuit of alternating current circuit that calculate
Measuring resistance in canonical parameter storehouse is compared with reactance ratio, determines circuit model, and exist according to the circuit model for determining
Measuring resistance, reactance, conductance and the susceptance value of the model circuit unit length are searched in line standard parameter library；
4) judge step 1) in the alternating current circuit information extracted whether containing alternating current circuit length information, if it has, then basis
Alternating current circuit length information and step 3) in the standard of the model circuit unit length that is found in line standard parameter library
Parameter value calculation obtains the standard value of the alternating current circuit parameter, into step 5)；Conversely, using the association between different line parameter circuit values
Relation sets up regression model, the length of alternating current circuit is estimated according to the regression model set up, then further according to estimation
Alternating current circuit length and step 3) in the standard ginseng of the model circuit unit length that is found in line standard parameter library
Numerical computations obtain the standard of appraisal value of the alternating current circuit parameter, into step 6)；
Regression model is set up using the incidence relation between different line parameter circuit values, the length of alternating current circuit is carried out according to regression model
Estimation, it is comprised the following steps：
1. historical data base is created：Complete and reasonably alternating current circuit ginseng that what historical data was extracted in BPA dat files fill in
Number, line length and circuit types；
2. regression equation is set up as follows：
La=ALr+BLx+CLb+D (1)
In formula, LaIt is the estimate of alternating current circuit length；LrIt is the resistance value filled in historical data divided by unit length standard electric
The line length that computing the resistor value is obtained；LxFor the reactance value filled in historical data is calculated divided by unit length standard inductance value
The line length for arriving；LbFor the susceptance value filled in historical data is long divided by the circuit that unit length normalized susceptance value is calculated
Degree；LwIt is the alternating current circuit length value filled in historical data；A, B, C, D are respectively coefficient value to be tried to achieve；It is residuals squares
With；N is the number of sample data in historical data；
3. regression equation is solved：Historical data is read from historical data base, treating in historical data solution formula (1) is asked
The set of coefficient value A, B, C, D is obtained, least square method is utilized according to formula (2), finding makes residual sum of squares (RSS)It is minimum value
The value of A, B, C, D, determines formula (1)；
4. alternating current circuit length is estimated：First according to step 1) in alternating current circuit information and step 3) in the unit that finds it is long
The measuring resistance of degree, reactance and susceptance value calculate Lr、LxAnd LbValue, the value that will be calculated substitutes into the public affairs 3. determined by step
Formula (1), is calculated the estimate L of line lengtha；
5) by step 4) obtained in the standard value of alternating current circuit parameter contrasted with the actual value of the alternating current circuit parameter,
Judge whether the standard value of the alternating current circuit parameter exceedes early warning threshold angle value set in advance with the deviation of actual value, if do not had
More than early warning threshold angle value, then the alternating current circuit parameter is filled in rationally, terminates parameter identification；Conversely, then by the alternating current circuit parameter
Actual value labeled as wrong or unreasonable data, and using step 4) obtained in the alternating current circuit parameter standard value as
The modified values of recommendation, while providing the standard value excursion of all the obtained alternating current circuit parameter of the model alternating current circuit
As the term of reference for manually correcting adjustment again, into step 7)；
6) by step 4) obtained in the standard of appraisal value of alternating current circuit parameter obtained with all of the model alternating current circuit
The standard value excursion of alternating current circuit parameter test, if the standard of appraisal value of the alternating current circuit parameter is in the model
Between the maximum and minimum value of the standard value excursion of all the obtained alternating current circuit parameter of alternating current circuit, then the friendship
Flow Line parameter is filled in rationally, terminates parameter identification；Conversely, being considered as unreasonable, and carried out with corresponding maximum or minimum value
Substitute, and mark instead identification, confirm during adjustment for manually being changed again, into step 7)；
7) output identification is the relevant information of wrong or unreasonable data.
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| CN105305432B (en) * | 2015-11-10 | 2018-03-02 | 国家电网公司 | A kind of alternating current circuit length estimation and discrimination method based on multiple regression analysis |
| CN106501673B (en) * | 2016-10-21 | 2019-03-08 | 国网江苏省电力有限公司检修分公司 | A kind of normal harmonic wave method of discrimination based on transmission line of electricity hidden danger electric discharge measured current traveling wave |
| CN107276092A (en) * | 2017-06-20 | 2017-10-20 | 国网北京经济技术研究院 | A kind of alternating current circuit length discrimination method based on parameters relationship |
| CN107749622A (en) * | 2017-10-26 | 2018-03-02 | 华北电力大学 | A kind of alternating current circuit type and parameter identification method based on identified parameters projection |
| CN110034532A (en) * | 2019-02-26 | 2019-07-19 | 国家电网公司华东分部 | The discrimination method and device of the actual measurement parameter of line impedance |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103745109A (en) * | 2014-01-10 | 2014-04-23 | 国家电网公司 | Bad data detection and identification method based on measurement of PMU (Phasor Measurement Unit) and measurement of SCADA (Supervisory Control and Data Acquisition) |
| CN103944165A (en) * | 2014-04-28 | 2014-07-23 | 国电南瑞科技股份有限公司 | Large power grid parameter recognition and estimation method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI264864B (en) * | 2005-04-08 | 2006-10-21 | Univ Chang Gung | Power flow calculation method of power grid with unified power flow controller |
-
2014
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103745109A (en) * | 2014-01-10 | 2014-04-23 | 国家电网公司 | Bad data detection and identification method based on measurement of PMU (Phasor Measurement Unit) and measurement of SCADA (Supervisory Control and Data Acquisition) |
| CN103944165A (en) * | 2014-04-28 | 2014-07-23 | 国电南瑞科技股份有限公司 | Large power grid parameter recognition and estimation method |
Non-Patent Citations (2)
| Title |
|---|
| PSD_BPA潮流计算数据卡的自动批量生成和修改;易杨等;《电力系统自动化》;20130525;第37卷(第10期);全文 * |
| 基于Karush-Kuhn-Tucker最优条件的电网可疑参数辨识与估计;曾兵等;《电网技术》;20100131;第34卷(第1期);全文 * |
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