CN114971007A - Photovoltaic power generation prediction method and system based on multi-scale graph convolutional neural network - Google Patents

Photovoltaic power generation prediction method and system based on multi-scale graph convolutional neural network Download PDF

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CN114971007A
CN114971007A CN202210560677.5A CN202210560677A CN114971007A CN 114971007 A CN114971007 A CN 114971007A CN 202210560677 A CN202210560677 A CN 202210560677A CN 114971007 A CN114971007 A CN 114971007A
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photovoltaic power
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杨会轩
苏明
李欣
刘金会
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Beijing Huaqing Future Energy Technology Research Institute Co ltd
Beijing Huaqing Zhihui Energy Technology Co ltd
Shandong Huake Information Technology Co ltd
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Beijing Huaqing Zhihui Energy Technology Co ltd
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    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F18/00Pattern recognition
    • G06F18/20Analysing
    • G06F18/25Fusion techniques
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    • G06Q50/06Electricity, gas or water supply
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    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
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    • H02J3/004Generation forecast, e.g. methods or systems for forecasting future energy generation
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Abstract

The invention provides a photovoltaic power generation prediction method and a photovoltaic power generation prediction system based on a multi-scale graph convolutional neural network, wherein an attention space-time convolution kernel is constructed, time and space characteristics of data of a plurality of photovoltaic power stations in the same area are respectively extracted by utilizing a 1x1 convolution and a 1x1 graph convolution, an attention mechanism is introduced to model the mutual relation of all moments, and the influence degree of the data at different moments on a prediction result is measured. According to the network construction method, Res2Net is introduced, the attention space-time convolution kernel is embedded into the Res2Net network, the space-time feature fusion of multiple scales is achieved, the multi-scale space-time feature expression is further achieved, and finally the photovoltaic power generation prediction of the multi-scale dynamic graph convolution neural network is achieved.

Description

Photovoltaic power generation prediction method and system based on multi-scale graph convolutional neural network
Technical Field
The invention relates to the technical field of photovoltaic power generation, in particular to a photovoltaic power generation prediction method and system based on a multi-scale graph convolutional neural network.
Background
In recent years, photovoltaic grid connection is gradually popularized in the world due to the characteristics of distributed operation, capability of reducing the pressure of a power transmission and distribution system, improvement on the reliability of a power grid and the like. The photovoltaic power station can only generate electric energy in the daytime, is a typical intermittent power supply, and has larger fluctuation and randomness because the power generation power is influenced by meteorological conditions such as solar irradiation intensity, ambient temperature and the like. Due to the characteristics of photovoltaic power generation, severe impact can be brought to the stable operation of a power grid when large-scale photovoltaic power generation is connected to the grid, and adverse effects can be caused to the whole power system. If the photovoltaic power generation power can be predicted timely and accurately, the influence of the fluctuation of the photovoltaic power generation on a power grid is greatly reduced, and the method has important significance on power grid dispatching and photovoltaic power station operation. Accurate photovoltaic power prediction helps to solve the problems faced by large-scale photovoltaic development and utilization. The prediction result can be used as a decision reference for power grid scheduling and photovoltaic power station operation and maintenance.
Currently, many researchers have studied photovoltaic power generation prediction. In the existing research, the prediction technology for photovoltaic power generation is mainly divided into two categories: physical methods, statistical methods. The physical method is mainly based on photovoltaic modules and weather conditions affecting power production: solar irradiance, temperature, etc. These techniques use mathematical models to convert weather conditions into opportunities for electrical energy. Statistical methods predict photovoltaic power generation over a future period of time by analyzing historical data. Compared with a physical method, the statistical method can be better suitable for photovoltaic power generation power prediction.
In photovoltaic power generation, a plurality of prediction models such as an artificial neural network, a support vector machine, a BP neural network and the like are well used for predicting photovoltaic power generation in a plurality of documents, but the common neural network prediction model cannot effectively capture the time and space characteristics of distributed photovoltaic stations at the same time, so that the prediction precision is influenced.
Disclosure of Invention
The invention provides a photovoltaic power generation prediction method and system based on a multi-scale graph convolutional neural network, which are used for solving the problem of low prediction precision of the conventional photovoltaic power generation prediction model.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a photovoltaic power generation prediction method based on a multi-scale graph convolution neural network, which comprises the following steps:
acquiring input information, and extracting time characteristics and space characteristics of photovoltaic power station data from the input information to form a space-time characteristic diagram, wherein the time characteristics are extracted through one-dimensional expansion convolution;
dividing the space-time feature graph into a plurality of feature sub-graphs along the channel dimension, calculating attention space-time convolution kernels corresponding to each feature sub-graph, wherein the attention space-time convolution kernels corresponding to the rest feature sub-graphs comprise space-time information of all previous feature sub-graphs except the attention space-time convolution kernel corresponding to the first feature sub-graph, and the feature sub-graphs and the corresponding attention space-time convolution kernels form space-time features of the current feature sub-graphs;
and splicing the space-time characteristics of various scales along the channel dimension to form spliced space-time characteristics consistent with the dimension of the input information, and performing weighted fusion on the space-time characteristics of various scales in the spliced space-time characteristics to obtain a photovoltaic power generation prediction result.
Further, the extracting of the time feature specifically includes:
Figure BDA0003654278440000021
wherein Z is the extracted time characteristic, delta is the Selu activation function,
Figure BDA0003654278440000022
and d is a one-dimensional expansion convolution operator, and H is the original data of the time characteristics of the photovoltaic power station.
Further, the spatial features are extracted by an approximate graph convolution operator, specifically:
the frequency domain plot convolution of the computation plot signal X with the convolution kernel Θ
Figure BDA0003654278440000023
Wherein
Figure BDA0003654278440000024
Is a graph convolution operator, L is a graph Laplacian matrix,
Figure BDA0003654278440000025
is a characteristic vector matrix of L, Λ is a diagonal matrix with the characteristic value of L as diagonal elements, and U is the characteristic vector matrix of L;
approximating the frequency domain graph convolution by a K-order Chebyshev polynomial
Figure BDA0003654278440000031
Wherein
Figure BDA0003654278440000032
Is a Chebyshev coefficient vector, T k (x) Is a chebyshev polynomial.
Further, the calculation of the attention space-time convolution kernel specifically includes:
performing aggregation operation on the features of the spatial feature map except time by using global average pooling to obtain global spatial features of all moments;
and mapping the correlation to a preset interval by using an activation function based on the correlation of the two full-connection layers at different moments to obtain a time weight coefficient, and distributing the time weight coefficient to the space characteristic diagram to obtain an attention space-time convolution kernel.
Further, the calculation of the global spatial feature at each time specifically includes:
Figure BDA0003654278440000033
in the formula, S t And the GAP represents the aggregation operation for the global space characteristic at the moment t,
Figure BDA0003654278440000034
is a space-time characteristic diagram at the time t,
Figure BDA0003654278440000035
is that
Figure BDA0003654278440000036
The value on node f channel at time n, N, F represents the number of nodes and the number of channels, respectively.
Further, the calculation of the weight coefficient specifically includes:
Figure BDA0003654278440000037
in the formula (I), the compound is shown in the specification,
Figure BDA0003654278440000038
for the weight coefficients, S is the global spatial feature, 2FC denotes two fully connected layers,
Figure BDA0003654278440000039
Figure BDA00036542784400000310
the parameter matrixes are related to two full connections respectively, r is a scaling rate, sigma is a sigmoid activation function, and delta is a Selu activation function.
Further, the attention spatiotemporal convolution kernel is calculated as:
Figure BDA00036542784400000311
in the formula, Q t
Figure BDA00036542784400000312
And
Figure BDA00036542784400000313
respectively representing attention space-time convolution kernels, weight coefficients and space-time feature maps at the time t.
Further, the process of splicing the spatiotemporal features of multiple scales along the channel dimension includes:
and introducing a Res2Net network structure to obtain the space-time correlation of the photovoltaic power station data in a multi-scale space-time feature fusion mode, and then utilizing a convolution layer to arrange the extracted space-time features into dimensions consistent with a prediction target.
The invention provides a photovoltaic power generation prediction system of a multi-scale dynamic graph convolution neural network, which comprises:
the data extraction unit is used for acquiring input information, extracting time characteristics and space characteristics of photovoltaic power station data from the input information to form a space-time characteristic diagram, and extracting the time characteristics through one-dimensional expansion convolution;
the data processing unit is used for dividing the spatio-temporal feature graph into a plurality of feature sub-graphs along the channel dimension, calculating attention spatio-temporal convolution kernels corresponding to each feature sub-graph, wherein the attention spatio-temporal convolution kernels corresponding to the other feature sub-graphs comprise spatio-temporal information of all previous feature sub-graphs except the attention spatio-temporal convolution kernel corresponding to the first feature sub-graph, and the feature sub-graphs and the corresponding attention spatio-temporal convolution kernels form spatio-temporal features of the current feature sub-graph;
and the power generation prediction unit is used for splicing the space-time characteristics of various scales along the channel dimension to form spliced space-time characteristics consistent with the dimension of the input information, and performing weighted fusion on the space-time characteristics of each scale in the spliced space-time characteristics to obtain a photovoltaic power generation prediction result.
A third aspect of the invention provides a computer storage medium having stored thereon computer instructions which, when run on the system, cause the system to perform the steps of the method.
The photovoltaic power generation prediction system according to the second aspect of the present invention can implement the methods according to the first aspect and the respective implementation manners of the first aspect, and achieve the same effects.
The effect provided in the summary of the invention is only the effect of the embodiment, not all the effects of the invention, and one of the above technical solutions has the following advantages or beneficial effects:
1. in the process of photovoltaic power generation prediction, the extracted space-time feature map is divided into a plurality of feature sub-maps, the space-time feature fusion of various scales is realized based on attention space-time convolution kernels, the relevance among all moments is considered in the attention space-time convolution kernels, the model expression capacity is improved, the time and space features of a photovoltaic power station can be effectively extracted, and the data characteristics are deeply mined, so that the prediction accuracy of the graph convolution neural network photovoltaic power generation prediction model is improved.
2. When time feature extraction is carried out, a one-dimensional expansion convolution is adopted to set an expansion rate, and a proper number of zero values are added among each element of a convolution kernel to control the dimensionality of the convolution kernel, so that the time dimensionality is adjusted nonlinearly, and the problem that the time feature memory is influenced by the convolution kernel with a fixed size is solved.
3. When the spatial feature is extracted, the Chebyshev approximation is carried out on the traditional graph convolution based on the frequency domain, and the complexity of formula calculation is reduced.
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In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present invention, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.
FIG. 1 is a schematic flow diagram of an embodiment of the method of the present invention;
FIG. 2 is a schematic diagram illustrating a process of constructing an attention spatiotemporal convolution kernel according to an embodiment of the method of the present invention;
FIG. 3 is a schematic diagram illustrating a data dimension variation corresponding to a weight coefficient calculation process in an embodiment of the method of the present invention;
fig. 4 is a schematic structural diagram of an embodiment of the system of the present invention.
Detailed Description
In order to clearly explain the technical features of the present invention, the following detailed description of the present invention is provided with reference to the accompanying drawings. The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. It should be noted that the components illustrated in the figures are not necessarily drawn to scale. Descriptions of well-known components and processing techniques and procedures are omitted so as to not unnecessarily limit the invention.
As shown in fig. 1, an embodiment of the present invention provides a photovoltaic power generation prediction method based on a multi-scale map convolutional neural network, where the method includes the following steps:
s1, acquiring input information, extracting time characteristics and space characteristics of photovoltaic power station data from the input information to form a space-time characteristic diagram, wherein the time characteristics are extracted through one-dimensional expansion convolution;
s2, dividing the space-time feature graph into a plurality of feature sub-graphs along the channel dimension, calculating attention space-time convolution kernels corresponding to each feature sub-graph, wherein the attention space-time convolution kernels corresponding to the rest feature sub-graphs comprise the space-time information of all previous feature sub-graphs except the attention space-time convolution kernel corresponding to the first feature sub-graph, and the feature sub-graphs and the corresponding attention space-time convolution kernels form the space-time features of the current feature sub-graph;
and S3, splicing the space-time characteristics of various scales along the channel dimension to form spliced space-time characteristics consistent with the dimension of the input information, and performing weighted fusion on the space-time characteristics of each scale in the spliced space-time characteristics to obtain a photovoltaic power generation prediction result.
As shown in fig. 2, in step S1, the time data is regarded as one-dimensional structured data, and the time feature is extracted by a one-dimensional convolutional neural network. Since the convolution kernel size of the convolutional neural network is fixed, the memory capacity of the convolutional neural network to the time characteristic can only be short-term. To alleviate this problem, the present invention employs one-dimensional dilation convolution to capture the temporal characteristics of photovoltaic plant data. As a special one-dimensional convolution, the dilated convolution can be performed by setting the dilation rate d at the convolution kernel
Figure BDA0003654278440000061
D-1 zero values are added between each element to control the dimension of the convolution kernel, thereby adjusting the time dimension non-linearly:
Figure BDA0003654278440000062
wherein δ is Selu activation function d Is a one-dimensional expansion convolution operator. Assume that the number of convolution kernels of the dilation convolution is C' and the size of the feature map is maintained using a padding operation. H is the raw data of the time characteristics of the photovoltaic power station.
After the time dimension of the photovoltaic power station data is subjected to feature extraction through one-dimensional expansion convolution, spatial feature extraction is performed on a plurality of photovoltaic power station data in the same area. Most of the existing photovoltaic power plant data prediction models use frequency domain based graph convolution.
The frequency domain graph convolution operation of the graph signal X with the convolution kernel Θ can be defined as:
Figure BDA0003654278440000071
wherein
Figure BDA0003654278440000072
Is a graph convolution operator, L is a graph Laplace matrix, and after normalization processing
Figure BDA0003654278440000073
I N Is a unit matrix which is formed by a plurality of unit matrixes,
Figure BDA0003654278440000074
the method is characterized in that the method is an L eigenvector matrix, D is a degree matrix, Λ is a diagonal matrix taking an eigenvalue of L as a diagonal element, U is an L eigenvector matrix, A is an adjacent matrix reflecting the internal connection condition of the graph X, and the calculation amount is large because the characteristic decomposition of Laplace of the formula is complex, and a K-order Chebyshev polynomial is adopted to approximate a graph convolution kernel:
Figure BDA0003654278440000075
wherein
Figure BDA0003654278440000076
A Chebyshev coefficient vector, a Chebyshev polynomial being defined as T k (x)=2xT k-1 (x)-T k-2 (x)T 0 (x)=1,T 1 (x) X. While
Figure BDA0003654278440000077
λ max Representing the maximum eigenvalue of L. By this approximation, the computational complexity of the above formula is greatly reduced.
In the historical data of the photovoltaic power station, the contribution of photovoltaic data at different times to the prediction result is different. Therefore, different weights are dynamically assigned to the features at different times according to the relationship between the features at the respective times, so that the model focuses on the features more favorable for the prediction result. According to the method, an attention mechanism is applied to the time dimension of photovoltaic power station data, the characteristics of each moment are integrated, the correlation among the characteristics of different moments is modeled, and further the weight is dynamically distributed to the space-time characteristics Z of each moment, so that valuable characteristics are emphasized, and the influence of invalid characteristics is weakened.
In step S3, the specific steps of calculating the attention space-time convolution kernel corresponding to each feature sub-graph are as follows:
firstly, global average pooling is utilized to align the spatio-temporal feature map
Figure BDA0003654278440000078
Performing aggregation operation on the features of other dimensions except time to obtain the global spatial features of all the moments
Figure BDA0003654278440000079
Then, the two fully-connected layers (2FC) consider the interrelation between different time instants by the following formula and map this relation to [0,1 ] using sigmoid activation function σ]Obtaining a time weight coefficient
Figure BDA00036542784400000710
Finally, the weight is assigned to
Figure BDA00036542784400000711
Deriving attention space-time convolution kernels
Figure BDA00036542784400000712
The whole process is formulated as follows:
Figure BDA0003654278440000081
Figure BDA0003654278440000082
Figure BDA0003654278440000083
in the formula
Figure BDA0003654278440000084
Is that
Figure BDA0003654278440000085
At time t n the value on node f-channel,
Figure BDA0003654278440000086
which are the parameter matrices involved in the two full connections, respectively, the parameter number of the module can be controlled by adjusting the scaling rate r.
Figure 3 shows a characteristic diagram
Figure BDA0003654278440000087
In generating the weight coefficients
Figure BDA0003654278440000088
The dimensions of the process vary.
In step S3, a multi-scale spatio-temporal map convolutional layer is proposed using the constructed attention spatio-temporal convolution kernel as a basic unit. As shown in FIG. 4, assume that the input to the system is
Figure BDA0003654278440000089
After 1x1 convolution processing, a characteristic diagram is obtained
Figure BDA00036542784400000810
Wherein F' is F × s. Then H is measured along the channel dimension (l) Are equally divided into s feature subgraphs, i.e.
Figure BDA00036542784400000811
Each sub-feature map has a corresponding attention space-time convolution kernel AST i (l) (. carries out space-time characteristic extraction on the signal and outputs Q i (l) 。H i (l) AST will be fused i-1 (l) Output Q of (c) i-1 (l) Are input to AST together i (l) In (c). Thus, each attention space-time convolution kernel AST i (l) All the previous sub-feature maps H are received j (l) J is less than or equal to iSpatio-temporal information. In order to reduce the parameter quantity of the model, the system omits the pair H 1 (l) And (4) extracting the space-time characteristics, and directly taking the space-time characteristics as the characteristics for recycling. The above process is described mathematically as:
Figure BDA00036542784400000812
the system then compares all the dimensions of the spatiotemporal feature Q i (l) Spliced along the dimension of the channel
Figure BDA00036542784400000813
Finally, for Q integrating s-order space-time characteristics (l) Polymerization is carried out to obtain (l) Dimensionally consistent
Figure BDA00036542784400000814
The aggregation operation aims to enable the model to dynamically adjust the importance of the space-time characteristics of different scales, so that the space-time characteristic expression of the node mixed scale is obtained, and the subsequent prediction task is completed more accurately. The specific implementation mode adopts an attention mechanism to carry out attention weighting on space-time characteristics at different positions.
Based on the cycle characteristics of photovoltaic power generation, weather conditions and illumination conditions of corresponding time periods from one day, one month or even one year before the target sequence is predicted can bring strong guiding significance to current prediction. In order to consider the periodicity of the photovoltaic power station data, the recent, monthly and yearly period sequences X of the photovoltaic power station data are respectively processed by 3 network components with the same structure r ,X m ,X y Is modeled.
Each component consists of a multi-scale space-time diagram convolutional layer and a convolutional layer, and a Res2Net network structure is introduced to obtain the space-time correlation of the photovoltaic power station data in a multi-scale space-time characteristic fusion mode. The extracted spatiotemporal features are then aligned into dimensions consistent with the predicted target using the convolutional layer. And finally, performing weighted fusion on the output of each component to obtain a final prediction result.
The invention provides a photovoltaic power generation prediction method based on a multi-scale dynamic graph convolution neural network, which constructs an attention space-time convolution kernel, respectively extracts time and space characteristics of data of a plurality of photovoltaic power stations in the same region by utilizing a 1x1 convolution and a 1x1 graph convolution, introduces an attention mechanism to model the interrelation of each moment, and measures the influence degree of the data at different moments on a prediction result. In a network construction method, Res2Net is introduced, the attention space-time convolution kernel is embedded into the Res2Net network, the space-time feature fusion of multiple scales is achieved, the multi-scale space-time feature expression is further achieved, and finally the photovoltaic power generation prediction of the multi-scale dynamic graph convolution neural network tray is achieved.
As shown in fig. 4, the invention further provides a photovoltaic power generation prediction system of a multi-scale dynamic graph convolution neural network, which comprises a data extraction unit 1, a data processing unit 2 and a power generation prediction unit 3.
The data extraction unit 1 is used for acquiring input information, extracting time characteristics and space characteristics of photovoltaic power station data from the input information to form a space-time characteristic diagram, and extracting the time characteristics through one-dimensional expansion convolution; the data processing unit 2 is configured to divide the spatio-temporal feature map into a plurality of feature sub-maps along a channel dimension, calculate an attention spatio-temporal convolution kernel corresponding to each feature sub-map, where the attention spatio-temporal convolution kernels corresponding to the remaining feature sub-maps include spatio-temporal information of all previous feature sub-maps except an attention spatio-temporal convolution kernel corresponding to a first feature sub-map, and the feature sub-maps and the corresponding attention spatio-temporal convolution kernels form spatio-temporal features of a current feature sub-map; the power generation prediction unit 3 is used for splicing the space-time characteristics of multiple scales along the channel dimension to form spliced space-time characteristics consistent with the input information dimension, and performing weighted fusion on the space-time characteristics of each scale in the spliced space-time characteristics to obtain a photovoltaic power generation prediction result.
The present invention also provides a computer storage medium having stored thereon computer instructions which, when run on the system, cause the system to perform the steps of the method.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.

Claims (10)

1. A photovoltaic power generation prediction method based on a multi-scale graph convolution neural network is characterized by comprising the following steps:
acquiring input information, and extracting time characteristics and space characteristics of photovoltaic power station data from the input information to form a space-time characteristic diagram, wherein the time characteristics are extracted through one-dimensional expansion convolution;
dividing the spatio-temporal feature graph into a plurality of feature sub-graphs along a channel dimension, calculating attention spatio-temporal convolution kernels corresponding to each feature sub-graph, wherein the attention spatio-temporal convolution kernels corresponding to other feature sub-graphs comprise spatio-temporal information of all previous feature sub-graphs except the attention spatio-temporal convolution kernel corresponding to the first feature sub-graph, and the feature sub-graphs and the corresponding attention spatio-temporal convolution kernels form spatio-temporal features of the current feature sub-graph;
and splicing the space-time characteristics of various scales along the channel dimension to form spliced space-time characteristics consistent with the dimension of the input information, and performing weighted fusion on the space-time characteristics of various scales in the spliced space-time characteristics to obtain a photovoltaic power generation prediction result.
2. The multi-scale graph convolutional neural network-based photovoltaic power generation prediction method of claim 1, wherein the extraction of the temporal features specifically comprises:
Figure FDA0003654278430000011
wherein Z is the extracted time characteristic, delta is the Selu activation function,
Figure FDA0003654278430000012
and d is a one-dimensional expansion convolution operator, and H is the original data of the time characteristics of the photovoltaic power station.
3. The method for predicting photovoltaic power generation based on the multi-scale graph convolutional neural network as claimed in claim 1, wherein the spatial features are extracted by an approximate graph convolution operator, and specifically comprise:
the frequency domain plot convolution of the computation plot signal X with the convolution kernel Θ
Figure FDA0003654278430000013
Wherein
Figure FDA0003654278430000014
Is a graph convolution operator, L is a graph laplacian matrix,
Figure FDA0003654278430000015
is a characteristic vector matrix of L, Λ is a diagonal matrix with the characteristic value of L as diagonal elements, and U is the characteristic vector matrix of L;
approximating the frequency domain plot convolution by a Chebyshev polynomial of order K
Figure FDA0003654278430000021
Wherein
Figure FDA0003654278430000022
Is a Chebyshev coefficient vector, T x (x) Is a chebyshev polynomial.
4. The method for predicting photovoltaic power generation based on the multi-scale graph convolutional neural network as claimed in claim 1, wherein the calculation of the attention space-time convolutional kernel specifically comprises:
performing aggregation operation on the features of the spatial feature map except time by using global average pooling to obtain global spatial features of all moments;
and mapping the correlation to a preset interval by using an activation function based on the correlation of the two full-connection layers at different moments to obtain a time weight coefficient, and distributing the time weight coefficient to the space characteristic diagram to obtain an attention space-time convolution kernel.
5. The multi-scale graph convolutional neural network-based photovoltaic power generation prediction method of claim 4, wherein the calculation of the global spatial features at each time is specifically as follows:
Figure FDA0003654278430000023
in the formula, S t And the GAP represents the aggregation operation for the global space characteristic at the moment t,
Figure FDA0003654278430000024
is a space-time characteristic diagram at the time t,
Figure FDA0003654278430000025
is that
Figure FDA0003654278430000026
The value on node f channel at time n, N, F represents the number of nodes and the number of channels, respectively.
6. The multi-scale graph convolutional neural network-based photovoltaic power generation prediction method of claim 5, wherein the weight coefficients are specifically calculated as follows:
Figure FDA0003654278430000027
in the formula (I), the compound is shown in the specification,
Figure FDA0003654278430000028
for the weight coefficients, S is the global spatial feature, 2FC denotes two fully connected layers,
Figure FDA0003654278430000029
Figure FDA00036542784300000210
the parameter matrixes are related to two full connections respectively, r is a scaling rate, sigma is a sigmoid activation function, and delta is a Selu activation function.
7. The method for predicting photovoltaic power generation based on the multi-scale graph convolutional neural network of claim 6, wherein the attention space-time convolutional kernel is calculated as:
Figure FDA00036542784300000211
in the formula, Q t
Figure FDA00036542784300000212
And
Figure FDA00036542784300000213
respectively representing attention space-time convolution kernels, weight coefficients and space-time feature maps at the time t.
8. The method for predicting photovoltaic power generation based on the multi-scale graph convolutional neural network as claimed in claim 1, wherein the process of splicing the multi-scale spatio-temporal features along the channel dimension comprises the following steps:
and introducing a Res2Net network structure to obtain the space-time correlation of the photovoltaic power station data in a multi-scale space-time feature fusion mode, and then utilizing a convolution layer to arrange the extracted space-time features into dimensions consistent with a prediction target.
9. A photovoltaic power generation prediction system based on a multi-scale graph convolution neural network is characterized by comprising:
the data extraction unit is used for acquiring input information, extracting time characteristics and space characteristics of photovoltaic power station data from the input information to form a space-time characteristic diagram, and extracting the time characteristics through one-dimensional expansion convolution;
the data processing unit is used for dividing the spatio-temporal feature graph into a plurality of feature sub-graphs along the channel dimension, calculating attention spatio-temporal convolution kernels corresponding to each feature sub-graph, wherein the attention spatio-temporal convolution kernels corresponding to the other feature sub-graphs comprise spatio-temporal information of all previous feature sub-graphs except the attention spatio-temporal convolution kernel corresponding to the first feature sub-graph, and the feature sub-graphs and the corresponding attention spatio-temporal convolution kernels form spatio-temporal features of the current feature sub-graph;
and the power generation prediction unit is used for splicing the space-time characteristics of various scales along the channel dimension to form spliced space-time characteristics consistent with the dimension of the input information, and performing weighted fusion on the space-time characteristics of each scale in the spliced space-time characteristics to obtain a photovoltaic power generation prediction result.
10. A computer storage medium having computer instructions stored thereon, which, when run on the system of claim 9, cause the system to perform the steps of the method of any one of claims 1-8.
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