CN105046038A - Method for estimating susceptance parameters of circuit - Google Patents
Method for estimating susceptance parameters of circuit Download PDFInfo
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- CN105046038A CN105046038A CN201510155246.0A CN201510155246A CN105046038A CN 105046038 A CN105046038 A CN 105046038A CN 201510155246 A CN201510155246 A CN 201510155246A CN 105046038 A CN105046038 A CN 105046038A
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Abstract
The invention discloses a method for estimating susceptance parameters of a circuit. The method is characterized in that identification and estimation on parameters are circularly calculated according to periods. One calculation comprises the following steps S1. acquiring real-time remotely measured data including active power P1 and P2, reactive power Q1 and Q2, voltages V1 and V2 at two sides a circuit; S2. calculating an estimated value of a present susceptance parameter; S3. storing the estimated value of the present susceptance parameter; and S4. calculating the weighted average of the stored estimated values of susceptance parameters as an output result. The method for estimating susceptance parameters of the circuit has no problem with value stability, and is simple, convenient to implement, and good in practicality at the same time.
Description
Technical field
The present invention relates to a kind of method of estimation of line admittance parameter.
Background technology
Device parameter is the important basic data of electric system.Inaccurate device parameter, can cause the aspect such as network analysis, safety and stability calculating to cause a deviation, cause the unreasonable of relay protection setting value.Improving parameter accuracy, is the problem with realistic meaning.At present, parameter is mainly derived from design parameter (nameplate parameter) and the actual measurement parameter of equipment, and design parameter and actual parameter may be inconsistent, and actual measurement parameter is usually subject to very strong undesired signal impact.Parameter estimation improves the important technical of parameter accuracy.In parameter estimation, existing common method is as follows: be the quantity of state of state estimation by parameter augmentation, passes through iterative.This method sometimes can obtain good result, but there is following problem: (1) the method numerical stability is poor, and frequent appearance does not restrain; (2) the method is not suitable for the circuit of radial pattern, limits range of application; (3) the method depends on good measuring section and stable state estimation procedure, needs more maintenance work.
Summary of the invention
The invention provides a kind of method of estimation of line admittance parameter, there is not numerical stability issues in it, and while method is simple, be convenient to implement, and has good practicality.
Present invention employs following technical scheme: a kind of method of estimation of line admittance parameter, it is characterized in that parameter identification is estimated is by loop cycle computation process, during single calculation, has the following step:
Step one, the real-time telemetry data of both sides, line taking road, comprising: the active-power P of circuit both sides
1and P
2; The reactive power Q of circuit both sides
1and Q
2; The voltage V of circuit both sides
1and V
2;
Step 2, calculates the susceptance estimates of parameters of current time;
Step 3, stores when secondary susceptance estimates of parameters;
Step 4, adds up the weighted mean of the susceptance estimates of parameters stored, as Output rusults.
In step one of the present invention, real-time telemetry data are SCADA data, PMU data, filtered SCADA data or filtered PMU data.
The susceptance estimated value calculating the current moment in step 2 of the present invention comprises the following steps:
First obtain successively
，
；
In formula: X is line reactance value;
，
；
，
；
Solve two quadratic equation with one unknown below respectively, B is unknown quantity:
，
Because quadratic equation with one unknown has two solutions, then by screening, select one and rationally separate,
Assuming that two of first equation solutions are respectively B1 and B2, screening mode is as follows:
If B1<0 & & is B2>0, get B=B2
If B1>0 & & is B2<0, get B=B1
If B1>0 & & is B2>0, get both solutions closer to B0, B0 is actual measurement or the design parameter of line admittance,
The screening mode of second equation is identical,
Assuming that the reasonable solution of two equations is respectively Ba, Bb, then the line admittance estimated is (Ba+Bb)/2.
The weighted mean of the calculating susceptance estimates of parameters described in step 4 of the present invention comprises the following steps:
Suppose there is n susceptance estimated value, the formula obtaining susceptance weighted mean value is as follows:
Wherein weighting coefficient
computing formula as follows:
In formula: molecule be during this period of time in circuit to gain merit the maximal value of absolute value, denominator is the meritorious absolute value of this moment circuit.
Store in step 3 of the present invention when secondary susceptance estimates of parameters, also need the absolute value of the circuit active power of simultaneously preserving current time, the holding time is 24 hours, and the form of preservation can be file or database.
The present invention has following beneficial effect: after have employed above technical scheme, the telemetry of both sides, line taking road of the present invention; Calculate the line admittance estimates of parameters in current moment, measure the method for direct estimation susceptance parameter according to circuit both sides, store the susceptance estimates of parameters of a period of time; Calculate a period of time weighted mean value, as Output rusults, would not numerical stability issues be there is like this, while method is simple, be convenient to enforcement, there is good practicality.
Accompanying drawing explanation
Fig. 1 is process flow diagram of the present invention.
Fig. 2 is the structural representation of a Typical Route in the embodiment of the present invention.
Embodiment
The present invention proposes a kind of line admittance method for parameter estimation, describes in detail below in conjunction with embodiment.
Line admittance parameter estimation is by loop cycle computation process, as shown in Figure 1.When single calculation, there is the following step:
Step one, the real-time telemetry data of both sides, line taking road, comprising: the active-power P of circuit both sides
1and P
2; The reactive power Q of circuit both sides
1and Q
2; The voltage V of circuit both sides
1and V
2;
Step 2, calculates the susceptance estimates of parameters of current time;
Step 3, stores when secondary susceptance estimates of parameters;
Step 4, adds up the weighted mean of the susceptance estimates of parameters stored, as Output rusults.
First the real-time telemetry data of both sides, line taking road, comprising: the active-power P of circuit both sides
1and P
2; The reactive power Q of circuit both sides
1and Q
2; The voltage V of circuit both sides
1and V
2; Here real-time telemetry data can be SCADA data, also can be PMU data; Also can be filtered SCADA data or filtered PMU data.Above-mentioned data can with reference to figure 2.
Calculate the susceptance estimated value in current moment, comprise the following steps:
Obtain successively:
，
；
In formula: x is line reactance value;
，
；
，
；
Solve two quadratic equation with one unknown (B is unknown quantity) below respectively:
，
；
Because quadratic equation with one unknown has two solutions, then by screening, select one and rationally separate.Assuming that two of first equation solutions are respectively B1 and B2, screening mode is as follows:
If B1<0 & & is B2>0, get B=B2
If B1>0 & & is B2<0, get B=B1
If B1>0 & & is B2>0, get both solutions (B0 is actual measurement or the design parameter of line admittance) closer to B0.
The screening mode of second equation is identical.
Assuming that the reasonable solution of two equations is respectively Ba, Bb, then the line admittance estimated is (Ba+Bb)/2.
Store when secondary susceptance estimates of parameters, also need the circuit simultaneously preserving current time to gain merit absolute value, the holding time is 24 hours.The form of preserving can be file or database.
When calculating the weighted mean of susceptance estimates of parameters, comprise the following steps:
Suppose there is n susceptance estimated value, the formula obtaining susceptance weighted mean value is as follows:
Wherein weighting coefficient
computing formula as follows:
In formula: molecule be during this period of time in circuit to gain merit the maximal value of absolute value, denominator is the meritorious absolute value of this moment circuit.
The present invention implements at several electrical networks, and form is below the example in Jiangsu Power Grid application.
Replace original value to carry out state estimation calculating the parameter value estimated, line related residual error obviously reduces, and illustrates that the line admittance parameter value estimated has reference significance.
The above embodiment only have expressed exemplary embodiment of the present invention, and it describes comparatively concrete and detailed, but therefore can not be interpreted as the restriction to the scope of the claims of the present invention.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be as the criterion with claims.
Claims (5)
1. a method of estimation for line admittance parameter, it is characterized in that parameter identification is estimated is by loop cycle computation process, during single calculation, has the following step:
Step one, the real-time telemetry data of both sides, line taking road, comprising: the active-power P of circuit both sides
1and P
2; The reactive power Q of circuit both sides
1and Q
2; The voltage V of circuit both sides
1and V
2;
Step 2, calculates the susceptance estimates of parameters of current time;
Step 3, stores when secondary susceptance estimates of parameters;
Step 4, adds up the weighted mean of the susceptance estimates of parameters stored, as Output rusults.
2. the method for estimation of line admittance parameter according to claim 1, is characterized in that in described step one, real-time telemetry data are SCADA data, PMU data, filtered SCADA data or filtered PMU data.
3. the method for estimation of line admittance parameter according to claim 1, is characterized in that the susceptance estimated value calculating the current moment in described step 2 comprises the following steps:
First obtain successively
,
, in formula: X is line reactance value;
，
；
，
Solve two quadratic equation with one unknown below respectively, B is unknown quantity:
，
Because quadratic equation with one unknown has two solutions, then by screening, select one and rationally separate,
Assuming that two of first equation solutions are respectively B1 and B2, screening mode is as follows:
If B1<0 & & is B2>0, get B=B2
If B1>0 & & is B2<0, get B=B1
If B1>0 & & is B2>0, get both solutions closer to B0, B0 is actual measurement or the design parameter of line admittance,
The screening mode of second equation is identical,
Assuming that the reasonable solution of two equations is respectively Ba, Bb, then the line admittance estimated is (Ba+Bb)/2.
4. the method for estimation of line admittance parameter according to claim 1, is characterized in that the weighted mean of the calculating susceptance estimates of parameters described in described step 4 comprises the following steps:
Suppose there is n susceptance estimated value, the formula obtaining susceptance weighted mean value is as follows:
Wherein weighting coefficient
computing formula as follows:
In formula: molecule be during this period of time in circuit to gain merit the maximal value of absolute value, denominator is the meritorious absolute value of this moment circuit.
5. the method for estimation of line admittance parameter according to claim 1, it is characterized in that storing when secondary susceptance estimates of parameters in described step 3, also need the absolute value of the circuit active power of simultaneously preserving current time, holding time is 24 hours, and the form of preservation can be file or database.
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Citations (6)
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| CN102495288A (en) * | 2011-12-08 | 2012-06-13 | 重庆大学 | Method for identifying and estimating power transmission line parameters based on SCADA (Supervisory Control and Data Acquisition) measurement data |
| CN102521677A (en) * | 2011-12-15 | 2012-06-27 | 中国电力科学研究院 | Optimal identification method of node equivalent transmission parameters based on single PMU measurement section |
| US20120283967A1 (en) * | 2009-09-25 | 2012-11-08 | Beijing Sifang Engineering Co., Ltd. | State-matrix-independent dynamic process estimation method in real-time for weakly observable measurement nodes without pmu |
| CN103838962A (en) * | 2014-02-18 | 2014-06-04 | 河海大学 | Step-by-step linear state estimation method with measurement of PMU |
| CN103972884A (en) * | 2014-04-24 | 2014-08-06 | 西南交通大学 | Electric system state estimation method |
-
2015
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101383511A (en) * | 2008-10-10 | 2009-03-11 | 清华大学 | Electrical power system status estimation method based on measurement data by data collection system |
| US20120283967A1 (en) * | 2009-09-25 | 2012-11-08 | Beijing Sifang Engineering Co., Ltd. | State-matrix-independent dynamic process estimation method in real-time for weakly observable measurement nodes without pmu |
| CN102495288A (en) * | 2011-12-08 | 2012-06-13 | 重庆大学 | Method for identifying and estimating power transmission line parameters based on SCADA (Supervisory Control and Data Acquisition) measurement data |
| CN102521677A (en) * | 2011-12-15 | 2012-06-27 | 中国电力科学研究院 | Optimal identification method of node equivalent transmission parameters based on single PMU measurement section |
| CN103838962A (en) * | 2014-02-18 | 2014-06-04 | 河海大学 | Step-by-step linear state estimation method with measurement of PMU |
| CN103972884A (en) * | 2014-04-24 | 2014-08-06 | 西南交通大学 | Electric system state estimation method |
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Application publication date: 20151111 |