CN107977510B - Fitting method for loss of direct current line - Google Patents

Fitting method for loss of direct current line Download PDF

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CN107977510B
CN107977510B CN201711237652.7A CN201711237652A CN107977510B CN 107977510 B CN107977510 B CN 107977510B CN 201711237652 A CN201711237652 A CN 201711237652A CN 107977510 B CN107977510 B CN 107977510B
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禤培正
朱继忠
谢平平
邹金
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Research Institute of Southern Power Grid Co Ltd
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Abstract

The invention discloses a fitting method of direct current line loss, relates to the technical field of electric power construction, and is used for solving the problem that the direct current line loss is difficult to accurately obtain at present. The fitting method comprises the following steps: respectively determining each transmission power, each loss rate and an average loss rate of the direct current line in a sampling period, and after removing abnormal data in an abnormal state in each transmission power, each loss and each loss rate, constructing a direct current line loss matrix by using the remaining transmission power, each loss and each loss rate; then, determining a segmentation point of the direct-current line loss matrix, and splitting the direct-current line loss matrix into at least two direct-current line loss sub-matrixes from the segmentation point; and finally, performing function fitting on each direct current line loss sub-matrix in the SPSS platform respectively to obtain a piecewise fitting function of the direct current line loss. The fitting method of the direct current line loss provided by the invention is used for obtaining the direct current line loss.

Description

Fitting method for loss of direct current line
Technical Field
The invention relates to the technical field of electric power construction, in particular to a fitting method of direct-current line loss.
Background
In a dc transmission network, electrical energy is transmitted from a power plant to a customer via a dc link through a plurality of transmission and distribution elements. Because the transmission distance of the direct current line is long and each power transmission and distribution element is provided with a resistor, a certain amount of direct current line loss can occur in links of power transmission, power transformation, power distribution and the like, and further economic benefits and social benefits of the direct current transmission network are easily lost. Therefore, it is necessary to analyze the loss of the dc line in detail to determine the energy saving and loss reducing measures suitable for the dc transmission network.
At present, the method for obtaining the loss of the dc line usually multiplies the square of the current in the dc line by the resistance, and uses the product as the loss value of the loss of the dc line. However, when the method is used to obtain the dc line loss, although the physical concepts of the current and the resistance in the dc line are clear and easy to obtain and calculate, the fluctuation of the current and the resistance in the actual operation of the dc line is not considered, that is, the current and the resistance in the actual operation of the dc line are not constant, because the converter station loss and other stray losses in the dc transmission network are ignored, the dc line loss obtained by the method is not accurate. Therefore, if the obtained dc line loss is not accurate, it is difficult to make energy saving and loss reduction measures suitable for the dc transmission network based on the dc line loss.
Disclosure of Invention
The invention aims to provide a fitting method of direct current line loss so as to obtain accurate direct current line loss.
In order to achieve the above purpose, the invention provides the following technical scheme:
a fitting method of direct current line loss comprises the following steps:
step 1, acquiring a plurality of sending end powers of a direct current line in a sampling period and receiving end powers corresponding to the sending end powers one to one; respectively determining corresponding transmission power, loss and loss rate of the direct current line according to the transmitting end power and the receiving end power;
step 2, determining the average loss rate of the direct current line according to the loss rates, and setting abnormal data removing conditions according to the average loss rate;
according to the abnormal data removing condition, respectively removing the abnormal data in the abnormal state in each transmission power, each loss and each loss rate;
step 3, taking each transmission power, each loss and each loss rate after abnormal data removal as three column vectors respectively, and constructing a direct current line loss matrix;
step 4, determining segmentation points of the direct-current line loss matrix, and splitting the direct-current line loss matrix into at least two direct-current line loss sub-matrices from the segmentation points;
and step 5, respectively carrying out function fitting on each direct current line loss sub-matrix on the SPSS platform for product statistics and service solution to obtain a piecewise fitting function of the direct current line loss.
Compared with the prior art, the fitting method for the loss of the direct current line provided by the invention has the following beneficial effects:
according to the fitting method for the loss of the direct-current line, provided by the invention, by acquiring a plurality of sending end powers and receiving end powers corresponding to the sending end powers in a sampling period of the direct-current line, the corresponding transmission power, loss rate and average loss rate of the direct-current line in actual operation can be respectively obtained according to the sending end powers and the receiving end powers; then removing abnormal data in an abnormal state in the transmission power, the loss and the loss rate, and constructing an accurate direct-current line loss matrix by using each transmission power, each loss and each loss rate after the abnormal data is removed; at the moment, the segmentation point of the direct current line loss matrix is determined, the direct current line loss matrix is split into at least two direct current line loss sub-matrices from the segmentation point, and the SPSS platform is used for performing function fitting on the direct current line loss sub-matrices respectively, so that a segmentation fitting function of the direct current line loss can be obtained.
Because each transmission power, each loss and each loss rate of the direct current line loss matrix are constructed by the method and the device, the transmission power, each loss and each loss rate are derived from each transmitting end power and each receiving end power in the actual operation of the direct current line, so that each loss in the direct current line loss matrix comprises converter station loss and other stray loss in the direct current transmission network, and the loss of the direct current line in the direct current transmission network can be truly reflected; and the direct current line loss matrix is divided into at least two direct current line loss sub-matrices, each direct current line loss sub-matrix is subjected to function fitting, and function fitting with higher matching degree can be respectively carried out on each direct current line loss sub-matrix which is in different curve changes, so that a piecewise fitting function of direct current line loss with higher accuracy is obtained, accurate direct current line loss is convenient to obtain, energy-saving loss reduction measures suitable for the direct current transmission network are worked out, and economic operation of the direct current transmission network is facilitated.
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The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a flowchart of a method for fitting dc line loss according to an embodiment of the present invention;
fig. 2 is a dispersion distribution diagram of the loss of the dc line according to the embodiment of the present invention;
fig. 3 is a scatter distribution diagram of the loss rate of the dc line according to the embodiment of the present invention;
fig. 4 is a scatter distribution diagram of the dc line loss after removing abnormal data according to the embodiment of the present invention;
FIG. 5 is a graph of a loss function fit of a first DC line loss submatrix provided by an embodiment of the present invention;
fig. 6 is a loss function fitting graph of a second dc line loss sub-matrix according to an embodiment of the present invention.
Detailed Description
For the convenience of understanding, the following describes the fitting method of the dc line loss provided by the embodiment of the present invention in detail with reference to the drawings in the specification.
Referring to fig. 1, a method for fitting dc line loss according to an embodiment of the present invention includes the following steps:
step S1, acquiring a plurality of sending end powers of the direct current line in a sampling period and receiving end powers corresponding to the sending end powers one to one; respectively determining corresponding transmission power, loss and loss rate of the direct current line according to the transmitting end power and the receiving end power;
step S2, determining the average loss rate of the direct current line according to the loss rates, and setting abnormal data removing conditions according to the average loss rate;
according to the abnormal data removing condition, respectively removing the abnormal data in the abnormal state in each transmission power, each loss and each loss rate;
step S3, taking each transmission power, each loss and each loss rate after abnormal data removal as three column vectors respectively, and constructing a direct current line loss matrix;
step S4, determining the segmentation points of the direct current line loss matrix, and splitting the direct current line loss matrix into at least two direct current line loss sub-matrices from the segmentation points;
and step S5, fitting each direct current line loss sub-matrix on the SPSS platform for product and service solution statistics to obtain a piecewise fitting function of the direct current line loss.
In specific implementation, according to the fitting method for the loss of the direct-current line provided by the embodiment of the invention, by acquiring a plurality of sending end powers of the direct-current line in a sampling period and receiving end powers corresponding to the sending end powers one to one, corresponding transmission power, loss rate and average loss rate of the direct-current line in actual operation can be respectively obtained according to the sending end powers and the receiving end powers; then, removing abnormal data in an abnormal state in the transmission power, the loss and the loss rate, and accurately constructing a direct current line loss matrix by using each transmission power, each loss and each loss rate after the abnormal data is removed; after that, by determining the segmentation points of the direct current line loss matrix, splitting the direct current line loss matrix from the segmentation points into at least two direct current line loss sub-matrices, and performing function fitting on each direct current line loss sub-matrix by using the SPSS platform, a segmentation fitting function of the direct current line loss can be obtained.
Because the embodiment of the invention is used for constructing each transmission power, each loss and each loss rate of the direct-current line loss matrix, the transmission power, each loss and each loss rate are derived from each transmitting end power and each receiving end power in the actual operation of the direct-current line, each loss in the direct-current line loss matrix comprises converter station loss and other stray loss in the direct-current transmission network, and the loss of the direct-current line in the direct-current transmission network can be truly reflected; and the direct current line loss matrix is divided into at least two direct current line loss sub-matrices, each direct current line loss sub-matrix is subjected to function fitting, and function fitting with higher matching degree can be respectively carried out on each direct current line loss sub-matrix which is in different curve changes, so that a piecewise fitting function of direct current line loss with higher accuracy is obtained, accurate direct current line loss is convenient to obtain, energy-saving loss reduction measures suitable for the direct current transmission network are worked out, and economic operation of the direct current transmission network is facilitated.
In step S1, the transmitting end power and the receiving end power of the dc link are generally obtained by the following method:
setting a sampling time interval T to N running moments, wherein a time interval T is formed between every two adjacent running moments; respectively collecting the transmitting end power P of the direct current line at the ith running time1(i)And receiving end power P2(i)(ii) a Wherein i is more than or equal to 1 and less than or equal to N. The sampling time period T, the number N of the running moments and the time interval T can be set according to actual needs.
Furthermore, the sending end power P is obtained1(i)And receiving end power P2(i)Then, the transmission power, loss rate, and average loss rate of the dc line are generally calculated by the following equations:
transmission power of DC line
Figure BDA0001489291980000051
Loss Δ P of DC line(i)＝P1(i)-P2(i)；
Loss rate of DC line
Figure BDA0001489291980000052
Average loss rate of DC line
Figure BDA0001489291980000053
Wherein, P(i)For transmitting power, Δ P(i)To be worn, mu(i)In order to achieve a high rate of loss,
Figure BDA0001489291980000054
and i is the average loss rate, i is the number of the time sequence in operation, and N is the total number of the operation time.
It is necessary to supplement that the average loss rate of the DC line is obtained
Figure BDA0001489291980000055
Then, the abnormal data removal condition in step S2 described above includes:
if it is not
Figure BDA0001489291980000056
The transmission power P of the dc link at the i-th operating moment is retained(i)Loss Δ P(i)And rate of wear mu(i)；
If it is not
Figure BDA0001489291980000057
Or
Figure BDA0001489291980000058
The transmission power P of the DC line at the i-th operating moment is removed(i)Loss Δ P(i)And rate of wear mu(i)。
To more clearly illustrate the fitting method of the dc line loss in the above embodiment, a dc transmission network with a dc line working condition resistance of 5.585 ohms, a voltage of 800kV, and a maximum transmission power of 5000MW is taken as an example, and is specifically described as follows.
In this embodiment, the sampling period T is 3 months, the time interval T is 5 minutes, and the sending end power P of the dc line1(i)And receiving end power P2(i)Can be obtained from the energy management system of the dc transmission network. At the time of obtaining the sending end power P1(i)And receiving end power P2(i)Then according to the aboveTransmission power P of the DC line(i)Loss Δ P(i)Loss rate mu(i)And average loss rate
Figure BDA0001489291980000059
Can obtain each transmission power P of the DC line respectively(i)Respective loss Δ P(i)Respective loss rate mu(i)And average loss rate
Figure BDA0001489291980000061
Wherein the DC line loss is Delta P(i)The dispersion point distribution diagram is shown in FIG. 2, the loss rate μ of the DC line(i)The dispersion point distribution diagram is shown in FIG. 3, and the loss Δ P of the DC line(i)The scatter distribution after removing outlier data is shown in FIG. 4.
The embodiment will remove the transmission power P after the abnormal data(i)As the first column vector, the loss Δ P after removing the abnormal data(i)As a second column vector, the loss rate μ after removing the abnormal data(i)Constructing a direct current line loss matrix as a third column vector; and making the DC line loss matrix according to each transmission power P in the first column vector(i)Arranged in order from small to large.
In order to accurately fit the dc link loss matrix, the determining the segmentation points of the dc link loss matrix in step S4 generally includes:
each transmission power P in the first column vector(i)In, successively assume a pre-segment power P*；
Assuming a pre-segment power P each time*Then according to the pre-segmentation power P*Pre-splitting the direct current line loss matrix into two direct current line loss sub-matrices, and obtaining a difference value of a third column vector standard deviation in the two direct current line loss sub-matrices;
comparing the difference values, and dividing the power P into segments corresponding to the maximum difference value*As the segmentation point of the dc link loss matrix.
In specific implementation, the power P is prescheduled every time*Then, the power P will be transmitted(i)∈(0，P*]The corresponding direct current line loss matrix part is used as a first direct current line loss sub-matrix, and a first standard deviation delta of a third column vector in the first direct current line loss sub-matrix is obtained1(ii) a At the same time, transmit power P(i)∈(P*，P(i)max]The corresponding part of the DC line loss matrix is used as a second DC line loss sub-matrix, and a second standard deviation delta of a third column vector in the second DC line loss sub-matrix is obtained2(ii) a And, a first standard deviation δ is calculated1And a second standard deviation δ2Where Δ δ is ═ δ1-δ2L. Then, the magnitude of each difference Δ δ is compared, and the maximum difference Δ δ is calculatedMAXAnd taking the corresponding pre-segmentation power P as a segmentation point of the direct current line loss matrix, and splitting the direct current line loss matrix.
Due to the transmission power P(i)When the loss rate is small, the converter station loss and the stray loss in the direct current transmission network account for the proportion of the total loss of the direct current line, so that the loss rate mu is larger at the moment(i)Is relatively large, i.e. the first standard deviation delta1Is large; while the transmission power P(i)When the loss rate is larger, the proportion of converter station loss and stray loss in the direct current transmission network to total loss of the direct current line is smaller, so that the loss rate mu at the moment(i)Is good, i.e. the second standard deviation delta2Is smaller. Therefore, the maximum difference Δ δMAXCorresponding pre-segmented power P*When the method is used as a segmentation point of a loss matrix of the direct-current line, the segmentation point is better, and the fitting accuracy of a loss segmentation fitting function of the direct-current line is improved.
It is necessary to supplement that the initial pre-segmentation power P*Typically, starting from 0, by a step s of 1% P(i)maxStepwise increase of pre-segment power P*Until the maximum difference delta is obtainedMAXI.e. to obtain better segmentation points. In this embodiment, the preferred segmentation point is the pre-segmentation power P *1000 MW; transmission power P(i)∈(0，1000MW]The corresponding DC line loss matrix part is a first DC line loss sub-matrix B1Transmitting powerP(i)∈(1000MW，5000MW]The corresponding part of the DC line loss matrix is a second DC line loss sub-matrix B2。
For the first DC line loss submatrix B in the SPSS platform1And a second DC line loss sub-matrix B2Respectively carrying out function fitting, and carrying out total selection on function types in a curve fitting window to obtain a first direct current line loss sub-matrix B1As shown in fig. 5 and table 1, a second dc line loss sub-matrix B2Is shown in fig. 6 and table 2.
Selecting a function expression with the highest determination coefficient from the fitting functions shown in Table 1, namely selecting the function expression as a first direct current line loss submatrix B1Is fitted to the function. Selecting a function expression with the highest determination coefficient from the fitting functions shown in Table 2, namely, selecting the function expression as a second direct current line loss sub-matrix B2Is fitted to the function.
TABLE 1 loss function fitting table for first DC line loss submatrix
Equation Function expression Determining coefficients b0 b1 b2 b3
Linear Y＝b0+b1*t 0.276 -3.341 0.027
Logarithmic Y＝1/((1/u)+b0*(b1^t)) 0.306 -116.984 20.376
Inverse Y＝b0+b1/t 0.329 37.637 -1.43E+04
Quadratic Y＝b0+b1*t+b2*t^2 0.378 -62.809 0.200 0
Cubic Y＝b0+b1*t+b2*t^2+b3*t^3 0.380 -43.366 0.116 0 -5.27E-08
Compound Y＝b0*b1^t 0.408 3.091 1.002
Power Y＝b0*t^b1 0.444 0.001 1.523
S Y＝e^(b0+b1/t) 0.469 4.193 -1059
Growth Y＝e^(b0+b1*t) 0.408 1.128 0.002
Exponential Y＝b0*e^(b1*t) 0.408 3.091 0.002
Logistic Y＝b0+b1*ln(t) 0.408 0.324 0.998
From each fitting function shown in table 1, the coefficient of certainty of the sigmoid function is the highest, and therefore, the first dc line loss submatrix B1The loss fitting function of (a) is:
Δp＝e(4.193-1059/p)；p∈(0,1000]MW。
TABLE 2 loss function fitting table for the second DC line loss submatrix
Equation Function expression Determining coefficients b0 b1 b2 b3
Linear Y＝b0+b1*t 0.975 -62.813 0.057
Logarithmic Y＝1/((1/u)+b0*(b1^t)) 0.912 -1.16E+03 160.118
Inverse Y＝b0+b1/t 0.774 262.675 -3.62E+05
Quadratic Y＝b0+b1*t+b2*t^2 0.985 -5.072 0.015 6.59E-06
Cubic Y＝b0+b1*t+b2*t^2+b3*t^3 0.985 16.62 -0.01 1.55E-05 -9.51E-10
Compound Y＝b0*b1^t 0.953 15.499 1.001
Power Y＝b0*t^b1 0.975 0 1.651
S Y＝e^(b0+b1/t) 0.92 6.075 -3.93E+03
Growth Y＝e^(b0+b1*t) 0.953 2.741 0.001
Exponential Y＝b0*e^(b1*t) 0.953 15.499 0.001
Logistic Y＝b0+b1*ln(t) 0.953 0.065 0.999
As can be seen from the fitting functions shown in table 2, the determination coefficients of the Quadratic function (Quadratic) and the Cubic function (Cubic) are the same and the highest, and considering that the expression of the Quadratic function is simpler than that of the Cubic function, the function expression corresponding to the Quadratic function is selected as the second dc line loss submatrix B2Loss fitting function of (2):
Δp＝6.59×10-6×p2+0.015×p-5.072；p∈(1000，5000]MW。
to sum up, the piecewise fitting function of the dc line loss in the dc transmission network of this embodiment is:
Figure BDA0001489291980000081
it should be noted that, in order to verify that the piecewise fitting function of the dc line loss obtained in the embodiment of the present invention has higher accuracy, please refer to fig. 1, where the fitting method of the dc line loss further includes:
and step S6, respectively obtaining the average absolute error and average relative error of the piecewise fitting function, and carrying out accuracy analysis on the piecewise fitting function.
Illustratively, the above equation for obtaining the mean absolute error of the piecewise fitting function is:
Figure BDA0001489291980000091
the above formula for obtaining the average relative error of the piecewise fitting function is:
Figure BDA0001489291980000092
wherein n is the total loss data amount in the corresponding fitting direct current line loss matrix of the piecewise fitting function, delta pkFor the kth loss value, Δ p, in the loss matrix of the DC linek' is and Δ pkThe corresponding piecewise fit function calculates a value.
In this embodiment, the average absolute error of the piecewise fitting function can be obtained by the above calculation formula of the average absolute error and the average relative error
Figure BDA0001489291980000093
Average relative error of its piecewise fitting function
Figure BDA0001489291980000094
Compared with other methods for acquiring the loss of the direct current line, for example:
the first method is to adopt a formula method in the prior art, namely, when the square sum of the current in the direct current line is multiplied by the resistance, and the product is taken as the loss value of the loss of the direct current line, 5.585 ohm working condition resistance and 800kV voltage of the direct current line in the direct current transmission network can be substituted into the formula:
Figure BDA0001489291980000095
to obtain a corresponding dc line loss function: Δ p is 8.73 × 10-6P2(ii) a At the moment, the average absolute error and the average relative error of the loss function of the direct current line are calculated, so that the average absolute error can be obtained
Figure BDA0001489291980000096
Average relative error thereof
Figure BDA0001489291980000097
In the second method, instead of segmenting the dc link loss matrix according to the fitting method provided in the embodiment of the present invention, the dc link loss matrix is directly fitted on the SPSS platform, so as to obtain a corresponding dc link loss function as follows:
Δp＝-6.03×10-10×p3+1.24×10-5×p2-0.003×p+11.248；p∈[0，5000)MW。
at the moment, the average absolute error and the average relative error of the loss function of the direct current line are calculated, so that the average absolute error can be obtained
Figure BDA0001489291980000098
Average relative error thereof
Figure BDA0001489291980000099
The embodiment of the invention provides an average absolute error of a fitting method of direct-current line loss
Figure BDA00014892919800000910
And average relative error
Figure BDA00014892919800000911
The minimum of the three methods is shown, which means that the piecewise fitting function of the dc line loss obtained by the embodiment of the present invention has higher accuracy compared with the prior art.
TABLE 3 accuracy comparison table of three fitting methods
Figure BDA0001489291980000101
In the foregoing description of embodiments, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims (6)

1. A fitting method for direct current line loss is characterized by comprising the following steps:
step 1, acquiring a plurality of sending end powers of a direct current line in a sampling period and receiving end powers corresponding to the sending end powers one to one; respectively determining corresponding transmission power, loss and loss rate of the direct current line according to the transmitting end power and the receiving end power;
step 2, determining the average loss rate of the direct current line according to the loss rates, and setting abnormal data removing conditions according to the average loss rate;
according to the abnormal data removal condition, removing abnormal data in an abnormal state in each transmission power, each loss and each loss rate;
step 3, taking each transmission power, each loss and each loss rate after abnormal data removal as three columns of column vectors respectively to construct a direct current line loss matrix;
step 4, determining a segmentation point of the direct current line loss matrix, and splitting the direct current line loss matrix into at least two direct current line loss sub-matrixes from the segmentation point;
step 5, performing function fitting on each direct current line loss submatrix respectively on a statistical product and service solution SPSS platform to obtain a piecewise fitting function of the direct current line loss;
in the direct current line loss matrix, each transmission power after abnormal data removal is a first column vector, each loss after abnormal data removal is a second column vector, and each loss rate after abnormal data removal is a third column vector;
the direct current line loss matrixes are arranged according to the sequence of the transmission power in the first column of the column vectors from small to large;
in step 4, determining the segmentation points of the dc link loss matrix includes:
successively assuming a pre-segmentation power P in each of the transmission powers of the first column vector*；
Assuming the pre-segment power P each time*Then, according to the pre-segmentation power P*Pre-splitting the direct current line loss matrix into two direct current line loss sub-matrices, and acquiring a difference value of a third column vector standard deviation in the two direct current line loss sub-matrices;
comparing the difference values, and dividing the power P into segments corresponding to the maximum difference value*And the direct current line loss matrix is used as a segmentation point of the direct current line loss matrix.
2. The method for fitting the direct-current line loss according to claim 1, wherein in step 1, the sending-end power and the receiving-end power are obtained by:
setting a sampling time interval T to N running moments, wherein a time interval T is formed between every two adjacent running moments;
respectively collecting the transmitting end power P of the direct current line at the ith running time1(i)And receiving end power P2(i)(ii) a Wherein i is more than or equal to 1 and less than or equal to N.
3. The method of claim 2, wherein the fitting of the DC line loss is based on the sending end power P1(i)And the receiving end power P2(i)，
The determination formula of the transmission power is as follows:
Figure FDA0002800951060000021
the loss is determined by the formula: delta P(i)＝P1(i)-P2(i)；
According to said loss Δ P(i)The determination formula of the loss rate is as follows:
Figure FDA0002800951060000022
according to the loss rate mu(i)The determination formula of the average loss rate is as follows:
Figure FDA0002800951060000023
wherein, P(i)For said transmission power, Δ P(i)For said loss, μ(i)In order to be said loss rate, the loss rate,
Figure FDA0002800951060000024
and i is the number of the time sequence in operation, and N is the total number of the operation time.
4. The method of claim 3, wherein the outlier removal condition comprises:
if it is not
Figure FDA0002800951060000025
The transmission power P of the dc link at the i-th operating moment is retained(i)Loss Δ P(i)And rate of wear mu(i)；
If it is not
Figure FDA0002800951060000026
Or
Figure FDA0002800951060000027
Removing the transmission power P of the DC line at the ith operation moment(i)Loss Δ P(i)And rate of wear mu(i)。
5. The method of fitting dc link losses according to any of claims 1-4, further comprising:
and 6, respectively obtaining the average absolute error and average relative error of the piecewise fitting function, and carrying out accuracy analysis on the piecewise fitting function.
6. The method of fitting DC line losses of claim 5,
the formula for obtaining the average absolute error of the piecewise fitting function is as follows:
Figure FDA0002800951060000031
the obtaining formula of the average relative error of the piecewise fitting function is as follows:
Figure FDA0002800951060000032
wherein n is the total loss data quantity, Δ p, in the loss matrix of the DC line correspondingly fitted by the piecewise fitting functionkFor the kth loss value, Δ p, in the DC line loss matrixk' is and Δ pkThe corresponding piecewise fit function calculates a value.
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1056737A (en) * 1996-08-07 1998-02-24 Toshiba Corp Distribution system operating equipment
CN102044881A (en) * 2010-12-31 2011-05-04 南方电网科学研究院有限责任公司 Design method for power transmission system line model
CN105039998A (en) * 2015-08-20 2015-11-11 南方电网科学研究院有限责任公司 Control method for cathode protection of high-voltage direct-current transmission grounding electrodes
CN106203714A (en) * 2016-07-14 2016-12-07 国网山东省电力公司电力科学研究院 Consider the HVDC transmission system maintenance optimization method on opportunity of operation of power networks risk
CN106908674A (en) * 2017-02-17 2017-06-30 国网上海市电力公司 A kind of Transformer condition evaluation based on the prediction of multimode amount
CN107255753A (en) * 2017-06-15 2017-10-17 中国电力科学研究院 A kind of hvdc transmission line corona loss method for transformation and its realize system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1056737A (en) * 1996-08-07 1998-02-24 Toshiba Corp Distribution system operating equipment
CN102044881A (en) * 2010-12-31 2011-05-04 南方电网科学研究院有限责任公司 Design method for power transmission system line model
CN105039998A (en) * 2015-08-20 2015-11-11 南方电网科学研究院有限责任公司 Control method for cathode protection of high-voltage direct-current transmission grounding electrodes
CN106203714A (en) * 2016-07-14 2016-12-07 国网山东省电力公司电力科学研究院 Consider the HVDC transmission system maintenance optimization method on opportunity of operation of power networks risk
CN106908674A (en) * 2017-02-17 2017-06-30 国网上海市电力公司 A kind of Transformer condition evaluation based on the prediction of multimode amount
CN107255753A (en) * 2017-06-15 2017-10-17 中国电力科学研究院 A kind of hvdc transmission line corona loss method for transformation and its realize system

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
A COMPREHENSIVE METHOD FOR RECONFIGURATION OF ELECTRICAL DISTRIBUTION NETWORK;Jizhong Zhu ET AL.;《2007 IEEE》;20071231;第1-7页 *
直流送受端故障对送端系统稳定性影响的对比分析及控制措施;张健，等;《电网技术》;20160430;第999-1004页 *

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