Method of calculating available output power of wind farm

Patent metadata

Field	Value
Publication number	US-9328719-B2
Application number	US-201414515530-A
Country	US
Kind code	B2
Filing date	Oct 16, 2014
Priority date	May 29, 2014
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

A method of calculating available output power of wind farm includes following steps. A space vector V k is obtained by decomposing a power sequence of benchmarking wind turbines in a wind farm based on empirical orthogonal function. A typical power sequence of the benchmarking wind turbines is calculated by restoring the space vector V k . A total power P total of a feeder on which the benchmarking wind turbines is operated is obtained by enlarging a typical power of each benchmarking wind turbine in proportion according to the quantity of the benchmarking wind turbines operated on the feeder. An output power P estimate of the wind farm is obtained by accumulating the total power P total of all the benchmarking wind turbines.

First claim

What is claimed is:

1. A method of calculating available output power of wind farm comprising:
obtaining a space vector V k by decomposing a power sequence of benchmarking wind turbines in a wind farm based on empirical orthogonal function;
calculating a typical power sequence P of the benchmarking wind turbines by restoring the space vector V k ;
getting a total power P total of a feeder on which the benchmarking wind turbines is operated by enlarging a typical power of each benchmarking wind turbine in proportion according to a quantity of the benchmarking wind turbines operated on the feeder;
accumulating the total power P total of all the benchmarking wind turbines.

2. The method of claim 1 , wherein the power sequence of benchmarking wind turbines in the wind farm is obtained through an output power of the wind farm in past one year.

3. The method of claim 2 , wherein the power sequence is defined through a number of benchmarking wind turbines and a time sequence, the number of benchmarking wind turbines is set for m, and a time sequence of each of the benchmarking wind turbines is set for n.

4. The method of claim 3 , wherein the wind farm is abstracted as a space field with m-dimensional random variable X, and a plurality of samples with a capacity of n is obtained in the space field.

5. The method of claim 4 , wherein the plurality of samples are defined as X i (1≦i≦n), and X i is an m-dimensional vector representing the benchmarking wind turbines denoted as:

X
t

=

∑

k
=
1

K

⁢

α
k

⁡

(
t
)

⁢

V
k

+

ɛ
t

,

wherein ε t is an m dimension error vector corresponding to the space vector V k , α k (t) is a time factor, which is a weighting factor while the k th space vector V k represents X t .

6. The method of claim 5 , wherein the space vector V k is obtained by:
obtaining a first space vector V 1 , wherein a residual error sum of squares E 1 in the formula:
E 1 =Var X−V 1 T ΣV 1   (3)

is smallest, wherein VarX is a total variance;
calculating a minimum value of E 1 and a V 1 corresponding to the minimum value of E 1 under the condition of V 1 T V 1 =1;
calculating variance contribution rate η:

η
=

Q
k

Var
⁢

⁢
X

=

λ
k

∑

k
=
1

m

⁢

λ
k

×
100
⁢
%

,

wherein Q k is a variance contribution of the space vector V k , λ k is a Lagrange multiplier.

7. The method of claim 6 , wherein the variance contribution Q k is a total number of the error variance reduced in the space field after the space vector V k is added into expansion of the formula of the residual error sum of squares E 1 .

8. The method of claim 7 , wherein the variance contribution Q k is obtained by:

Q
k

=

E

k
-
1

-

E
k

=

(

Var
⁢

⁢
X

-

∑

l
=
1

k
-
1

⁢

λ
l

)

-

(

Var
⁢

⁢
X

-

∑

l
=
1

k

⁢

λ
l

)

=

λ
k

.

Assignees

• State Grid Corp China
• Gansu Electric Power Company of State Grid
• Wind Power Technology Ct Of Gansu Electric Power Company
• Univ Tsinghua

Inventors

• Lu Liang
• Wang ning-bo
• Qiao Ying
• Lu zong-xiang
• Lv qing-quan
• Zhao Long

Classifications

• F03D9/005 Primary

  Mechanical Engineering · mapped topic

• F03D7/00

  Controlling wind motors  (supplying or distributing electrical power H02J, e.g. arrangements for adjusting, eliminating or compensating reactive power in networks H02J3/18; controlling electric generators H02P, e.g. arrangements for controlling electric generators for the purpose of obtaining a desired output H02P9/00) · CPC title

• F03D7/048 Primary

  controlling wind farms · CPC title

• F03D7/028

  controlling wind motor output power · CPC title

• F05B2260/821

  Parameter estimation or prediction · CPC title