CN107734020B - Coordinated operation method for data transmission congestion of multiple photovoltaic power stations - Google Patents

Abstract

The invention provides a coordinated operation method for data transmission congestion of a plurality of photovoltaic power stations, and relates to the field of power grid dispatching. A coordinated operation method for data transmission congestion of a plurality of photovoltaic power stations comprises the steps of analyzing and calculating parameters influencing data priority grading, and then describing initial dynamic priorities of data of the photovoltaic power stations by using functions. And (3) constructing an optimized distribution function by combining the environmental parameters influencing data transmission of each photovoltaic power station and the power generation power coefficient, and setting a proper priority threshold. And the optimal distribution function value of data transmission is compared with the priority threshold value set value to complete the classification of the priority, and finally, the priority distribution of the overall data of each photovoltaic power station is realized. According to the coordinated operation method for data transmission congestion of the photovoltaic power stations, provided by the invention, data with high priority can be processed preferentially, the problem of data congestion is solved, and the utilization efficiency and the processing speed of information data of each photovoltaic power station are improved.

Description

A coordinated operation method for data transmission congestion of multiple photovoltaic power stations

technical field

The invention relates to the technical field of power grid scheduling, in particular to a coordinated operation method for data transmission congestion of multiple photovoltaic power stations.

Background technique

At present, with the gradual warming of the topic of environmental protection, the development of new energy has become a key project of energy development. As the most representative new energy, solar energy has become the strategic focus of energy development. In the safe operation system of the power grid, the photovoltaic power station should have the ability to transmit remote information to the dispatching terminal of the power system, upload the photovoltaic power generation power prediction parameters, power quality information, solar light intensity, solar incidence angle, and installation of photovoltaic arrays in the photovoltaic power station. Angle, conversion efficiency, atmospheric pressure, temperature and other environmental parameters, as well as some random factor parameters. Then, it accepts the dispatch of the power system, and executes the active and reactive power control transmitted by the power system dispatch. However, as a new energy generation, solar photovoltaic is intermittent and unstable, and its accurate prediction has certain difficulties, which also brings difficulties to the intelligent control of grid dispatching, especially when data transmission of multiple photovoltaic power stations. Therefore, it is very important to study the dispatching of photovoltaic systems in the power grid.

At present, large-scale photovoltaic grid-connected systems have been widely used. In the existing power grid dispatching, most of them predict the output power of solar photovoltaic power generation in advance, and the power grid dispatching department will coordinate and coordinate according to the output power curve. When each photovoltaic power station transmits parameter information at the same time, information processing is not timely, and important parameters cannot be processed first, resulting in the problem of data "congestion". Solving this problem can effectively improve the data utilization efficiency and processing speed of each photovoltaic power station. .

SUMMARY OF THE INVENTION

In view of the defects of the prior art, the present invention provides a coordinated operation method for data transmission congestion of multiple photovoltaic power stations, so as to solve the problem of data congestion during scheduling.

A coordinated operation method for data transmission congestion of multiple photovoltaic power stations, comprising the following steps:

Step 1: According to the actual operating state, specific dynamic performance, and local geographical conditions of different photovoltaic power stations, and based on the data transmitted by the photovoltaic power stations to the dispatch center, select the parameter indicators that affect the priority classification of photovoltaic power stations;

The selected parameter indicators include the geographic distance Li between each photovoltaic power station and the dispatch station, the power generation power coefficient P _i of each photovoltaic power station, the power quality index Z _i , the accuracy index C _i of the transmitted data _, and the photovoltaic panel array. Installation angle θ _i , conversion efficiency per unit area of photovoltaic panels χ _i , average temperature of photovoltaic panels T _bi , atmospheric pressure qi in the area where each photovoltaic power station is located, ambient temperature _Tri and sunlight intensity I _i , where _i =1, 2....n is the ith photovoltaic power station, n is the total number of photovoltaic power stations that need to be prioritized;

Step 2: Find the initial priority function U _i that describes the relationship between the dynamic change of the initial priority of each photovoltaic power station and the urgency of data transmission at different times, and determine whether the initial priority function U _i of each process is greater than zero, if If it is greater than zero, perform step 3, otherwise stop processing the information data of photovoltaic power stations whose initial priority function U _i is less than or equal to zero;

The initial priority function U _i , which describes the relationship between the dynamic change of the initial priority of each photovoltaic power station and the urgency of the data transmitted at different times, is calculated as follows:

In the formula, Δt _i is the time interval between two adjacent data transmissions of the i-th photovoltaic power station; T is the time for all photovoltaic power stations dispatched by the dispatch center to complete one cycle of data transmission, and α and β are the respective photovoltaic power stations. The attenuation factor of the power station with respect to time and distance, 0<α<1, 0<β<1.

Step 3: Calculate the power generation power coefficient P _i of each photovoltaic power station, the environmental change factor η _i , the power quality index Z _i and the transmission data accuracy index C _i , calculate the value of each photovoltaic power station whose initial priority function U _i is greater than zero. Comprehensive initial priority coefficient K _i ;

The power generation coefficient P _i of each photovoltaic power station is calculated according to the actual power generation power P _iW , light intensity I _i , photovoltaic power conversion efficiency χ _i and ambient temperature _Tri of each photovoltaic power station, and the calculation formula is as follows:

Among them, k _i1 , k _i2 , and k _i3 are the weighting coefficients reflecting the influence of light intensity, photovoltaic power conversion efficiency and ambient temperature on the i-th photovoltaic power station respectively, P _iN is the rated power generation of the i-th photovoltaic power station, P _iW is the actual power generation of the i-th photovoltaic power station, and its calculation formula is as follows:

P _iW =χ _i S _i I _i [1-0.0046(T _ri +18)]

In the formula, S _i is the total area of the i-th photovoltaic power station panel.

The environmental change factor η _i of each photovoltaic power station is calculated according to the installation angle θ _i of the photovoltaic array of each photovoltaic power station, the conversion efficiency χ _i , the atmospheric pressure q _i , the ambient temperature _Tri and the average temperature T _bi of the photovoltaic cell panel. The formula is as follows:

Among them, η _i is the environmental change factor of the ith photovoltaic power station.

According to the calculated power generation power coefficient P _i of each photovoltaic power station, the environmental change factor η _i , the power quality index Z _i and the transmission data accuracy index C _i , the comprehensive initial priority coefficient K _i of each photovoltaic power station is obtained. The formula looks like this:

Step 4: The priority dynamic change function U _i established by each photovoltaic power station in step 2, the comprehensive initial priority coefficient K _i of each photovoltaic power station in step 3, and the environmental change factor η _i to the initial priority function U _i Each photovoltaic power station greater than zero establishes an optimal dispatch allocation function _Qi , and the dispatch optimal allocation function _Qi is shown in the following formula:

为调度站实现调度的时间段，σ为数据传输调节系数；In the formula,

is the time period for the scheduling station to achieve scheduling, σ is the data transmission adjustment coefficient;

Step 5: According to the scheduling optimal allocation function Q _i established by each photovoltaic power station, uniformly schedule the data information of each photovoltaic power station whose initial priority function U _i is greater than zero. The specific method is as follows:

Step 5.1: Accept the information data sent by each photovoltaic power station, and use the scheduling optimal allocation function _Qi to calculate the priority of each information data;

Step 5.2: According to the historical data transmitted by each photovoltaic power station, set a priority threshold W, and compare the optimal function _Qi value of each photovoltaic power station with the value range of the priority threshold W. If the photovoltaic power station information data The optimal distribution function _Qi value of the photovoltaic power station is within the value range of the priority threshold W, then the information data of the photovoltaic power station is placed in the high priority sequence; if the optimal distribution function _Qi value of the photovoltaic power station information data is less than If the minimum value of the priority threshold W, the information data of the photovoltaic power station is placed in the low priority sequence; if the optimal distribution function _Qi value of the information data of the photovoltaic power station is greater than the maximum value of the priority threshold W, the information data of the photovoltaic power station is placed in the low priority sequence; The information data of the photovoltaic power station is placed in the middle priority sequence;

Using Y to represent the priority grading sequence, the expression of the PV power station priority grading sequence is:

Step 5.3: Sort the data information of each photovoltaic power station according to the priority, so as to realize unified scheduling of the data information of each photovoltaic power station.

As can be seen from the above technical solutions, the beneficial effect of the present invention is that: the present invention provides a coordinated operation method for data transmission congestion of multiple photovoltaic power stations, which is based on the wind power power factor, power quality factor, and power prediction of each photovoltaic power station. Impact Calculates factors that affect scheduling priority. By establishing the initial priority function, the initial priority of each photovoltaic power station and the relationship between the data transmitted at different times are described, and the parameters affecting the final priority are calculated with reference to the known variables, so as to prepare for the establishment of a mathematical model of data processing priority. By further constructing the mathematical model of the final priority function, the priority classification of the data of each photovoltaic power station is obtained. Finally, the objective function is constructed with different photovoltaic power stations as variables, and the data transmission is processed according to the designed optimization and coordination method, so that the data with high priority is processed first, which solves the congestion problem of multiple photovoltaic power stations in data transmission, and improves the performance of each photovoltaic power generation. The utilization efficiency and processing speed of the information data of the station.

Description of drawings

FIG. 1 is a flowchart of a coordinated operation method for data transmission congestion of multiple photovoltaic power stations according to an embodiment of the present invention.

Detailed ways

The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments. The following examples are intended to illustrate the present invention, but not to limit the scope of the present invention.

Step 1: According to the actual operating state, specific dynamic performance, and local geographical conditions of different photovoltaic power stations, and based on the data transmitted by the photovoltaic power stations to the dispatch center, select the parameter indicators that affect the priority classification of photovoltaic power stations;

The selected parameter indicators include the geographic distance Li between each photovoltaic power station and the dispatch station, the power generation power coefficient P _i of each photovoltaic power station, the power quality index Z _i , the accuracy index C _i of the transmitted data _, and the photovoltaic panel array. Installation angle θ _i , conversion efficiency per unit area of photovoltaic panels χ _i , average temperature of photovoltaic panels T _bi , atmospheric pressure qi in the area where each photovoltaic power station is located, ambient temperature _Tri and sunlight intensity I _i , where _i =1, 2....n is the ith photovoltaic power station, n is the total number of photovoltaic power stations that need to be prioritized;

This embodiment collects and detects the data of three photovoltaic power stations dispatched by a dispatch station in a certain area from March 2016 to June 2016, and obtains parameter indicators that affect the priority classification of photovoltaic power stations. The geographical distance between the first photovoltaic power station and the dispatching station is L ₁ =20km, the power quality index of the photovoltaic power station is Z ₁ =8, the accuracy index of transmission data is C ₁ =12.5, and the average solar light intensity I ₁ =550km/m ² , the installation angle of the photovoltaic panel array θ ₁ =45°, the conversion efficiency of the photovoltaic panel per unit area χ ₁ =12%, the atmospheric pressure q ₁ =101kp, the ambient temperature T _r1 =23°C, the average temperature of the photovoltaic panel T _b1 =26 ℃; the geographic distance L ₁ =38km from the second photovoltaic power station to the dispatching station, the power quality index of the photovoltaic power station Z ₂ =10, the accuracy index of the data transmitted by the photovoltaic power station C ₂ =15, the average solar power of the photovoltaic power station The light intensity I ₂ =500km/m ² , the installation angle of the photovoltaic panel array θ ₂ =40°, the conversion efficiency of the photovoltaic panel per unit area χ ₂ =10%, the atmospheric pressure q ₂ =101kp, the ambient temperature T _r2 =21°C, The average temperature of photovoltaic panels T _b2 = 25°C; the geographic distance of the third photovoltaic power station from the dispatch station L ₃ =40km, the power quality index of the photovoltaic power station Z ₃ =8, and the accuracy index of the data transmitted by the photovoltaic power station C ₃ =13.5, the average solar light intensity of the photovoltaic power station I ₃ =450km/m ² , the installation angle of the photovoltaic panel array θ ₃ =35°, the conversion efficiency of the photovoltaic panel per unit area χ ₃ =11%, the atmospheric pressure q ₃ =100kp , the ambient temperature T _r3 =24°C, and the average temperature of the photovoltaic cell panel T _b2 =27°C.

Step 2: Find the initial priority function U _i that describes the relationship between the dynamic change of the initial priority of each photovoltaic power station and the urgency of data transmission at different times, and determine whether the initial priority function U _i of each process is greater than zero, if If it is greater than zero, perform step 3, otherwise stop processing the information data of photovoltaic power stations whose initial priority function U _i is less than or equal to zero;

The calculation formula of the initial priority function U _i is as follows:

In the formula, Δt _i is the time interval between two adjacent data transmissions of the i-th photovoltaic power station; T is the time for all photovoltaic power stations dispatched by the dispatch center to complete one cycle of data transmission, and α and β are the respective photovoltaic power stations. The attenuation factor of the power station with respect to time and distance, 0<α<1, 0<β<1;

In this embodiment, according to the data collection platform of the photovoltaic power station, the time interval Δt ₁ =0.5s for the first two adjacent data transmissions of the photovoltaic power station, and the time interval Δt for the two adjacent data transmissions for the second photovoltaic power station ₂ = 0.3s, the time interval Δt ₃ = 0.8s for two adjacent data transmissions of the third photovoltaic power station, and one cycle T = 5s for all three photovoltaic power stations to complete data transmission. The attenuation factors α and β of time and distance are taken as α=0.67 and β=0.77, respectively. The initial priority function values of the three photovoltaic power stations are calculated as: U ₁ =19.33375, U ₁ =25.37556, U ₁ =20.12778. In this embodiment, the calculated initial priority function values U ₁ , U ₂ , and U ₃ of the three photovoltaic power stations are all greater than zero, and the data information needs to be scheduled uniformly.

Step 3: Calculate the synthesis of each photovoltaic power station whose initial priority function U _i is greater than zero from the power generation power coefficient P _i of each photovoltaic power station, the environmental change factor η _i , the power quality index Z _i and the transmission data accuracy index C _i . The initial priority coefficient K _i , the specific method is:

The calculation formula of the power generation power coefficient P _i of each photovoltaic power station is as follows:

Among them, k _i1 , k _i2 , and k _i3 are the weighted coefficients of the influence of the reflected light intensity, photovoltaic power conversion efficiency and ambient temperature on the i-th photovoltaic power station, P _iN is the rated power generation of the i-th photovoltaic power station, P _iW is the actual power generation of the i-th photovoltaic power station, and its calculation formula is as follows:

P _iW =χ _i S _i I _i [1-0.0046(T _ri +18)]

In the formula, S _i is the total area of the i-th photovoltaic power station panel;

In this embodiment, the total areas of the panels of the three photovoltaic power stations are: S ₁ =2200m ² , S ₂ =2800m ² , S ₃ =2400m ² , and the calculated generating powers of the three photovoltaic power stations are: P _1W =830KW, _P2W =1560KW, _P3W =890KW.

In this embodiment, the rated generating powers of the three photovoltaic power stations are: P _1N =1000KW, P _2N =1800KW, P _3N =1300KW; the weighting coefficients of the first photovoltaic power station are: k ₁₁ =15, k ₁₂ =10, k ₁₃ =20; the weighting coefficients of the second photovoltaic power station are: k ₂₁ =24, k ₂₂ =18, k ₂₃ =10; the weighting coefficients of the third photovoltaic power station are: k ₂₁ =17, k ₂₂ =18, k ₂₃ =27. According to the calculation, the power generation coefficients of each photovoltaic power station are: P ₁ =132.99, P ₂ =148.84, and P ₃ =124.68.

The calculation formula of the environmental change factor η _i of each photovoltaic power station is as follows:

Among them, η _i is the environmental change factor of the ith photovoltaic power station;

In this embodiment, calculated according to the given formula and data, the environmental change factors of each photovoltaic power station are: η ₁ =25.66, η ₂ =31.05, and η ₃ =18.29.

The calculation formula of the comprehensive initial priority coefficient K _i of each photovoltaic power station is as follows:

In this embodiment, the calculated environmental change factors of the photovoltaic power station are K ₁ =15.88, K ₂ =20.55, and K ₃ =22.58.

Step 4: The priority dynamic change function U _i established by each photovoltaic power station in step 2, the comprehensive initial priority coefficient K _i of each photovoltaic power station in step 3, and the environmental change factor η _i to the initial priority function U _i Each photovoltaic power station greater than zero establishes an optimal dispatch allocation function _Qi , and the dispatch optimal allocation function _Qi is shown in the following formula:

为调度站实现调度的时间段，σ为数据传输调节系数；In the formula,

is the time period for the scheduling station to achieve scheduling, σ is the data transmission adjustment coefficient;

In this embodiment, according to the time period of data collection, the value of H is 2.5, and the data transmission adjustment coefficient σ=0.6. After calculation, the optimal dispatching distribution function values of each photovoltaic power station are obtained as: Q ₁ =58, Q ₂ =75, Q ₃ =81.

Step 5: According to the scheduling optimal allocation function Q _i established by each photovoltaic power station, uniformly schedule the data information of each photovoltaic power station whose initial priority function U _i is greater than zero. The specific method is as follows:

Step 5.1: Accept the information data sent by each photovoltaic power station, and use the scheduling optimal allocation function Qi to _analyze and calculate the priority of each information data;

Step 5.2: According to the historical data transmitted by each photovoltaic power station, set a priority threshold W, and compare the optimal function _Qi value of each photovoltaic power station with the value range of the priority threshold W. If the photovoltaic power station information data The optimal distribution function _Qi value of the photovoltaic power station is within the value range of the priority threshold W, then the information data of the photovoltaic power station is placed in the high priority sequence; if the optimal distribution function _Qi value of the photovoltaic power station information data is less than If the minimum value of the priority threshold W, the information data of the photovoltaic power station is placed in the low priority sequence; if the optimal distribution function _Qi value of the information data of the photovoltaic power station is greater than the maximum value of the priority threshold W, the information data of the photovoltaic power station is placed in the low priority sequence; The information data of the photovoltaic power station is placed in the middle priority sequence;

Using Y to represent the priority grading sequence, the expression of the PV power station priority grading sequence is:

Step 5.3: Sort the data information of each photovoltaic power station according to the priority, so as to realize unified scheduling of the data information of each photovoltaic power station.

得出第一座光伏发电站的优先级为Y₂，第二座光伏发电站的优先级为Y₁，第三座光伏发电站的优先级为Y₃。最后根据得出的优先级分级对各发电站进行排序，得到调度中心对三座光伏发电站的顺序为第二座光伏发电站-第一座光伏发电站-第三座光伏发电站。In this embodiment, the priority threshold is set to 50≤W≤80. According to the given PV power station priority classification expression,

It is obtained that the priority of the first photovoltaic power station is Y ₂ , the priority of the second photovoltaic power station is Y ₁ , and the priority of the third photovoltaic power station is Y ₃ . Finally, the power stations are sorted according to the obtained priority classification, and the order of the three photovoltaic power stations by the dispatch center is obtained as the second photovoltaic power station - the first photovoltaic power station - the third photovoltaic power station.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope defined by the claims of the present invention .

Claims (1)

1. A coordinated operation method for data transmission congestion of a plurality of photovoltaic power stations is characterized by comprising the following steps: the method specifically comprises the following steps:

step 1: according to actual running states, specific dynamic performance and local geographical conditions of different photovoltaic power stations, selecting parameter indexes influencing priority grading of the photovoltaic power stations on the basis of data transmitted to a dispatching center by the photovoltaic power stations;

the selected parameter index comprises the geographical distance L between each photovoltaic power station and the dispatching station_iPower generation coefficient P of each photovoltaic power station_iElectric energy quality index Z_iAccuracy index C of transmitted data_iMounting angle theta of photovoltaic cell panel array_iPhotovoltaic cell panel unit area conversion efficiency x_iAverage temperature T of photovoltaic cell panel_biAtmospheric pressure q of the area of each photovoltaic power plant_iAmbient temperature T_riAnd intensity of solar radiation I_iN is the ith photovoltaic power station, and n is the total number of the photovoltaic power stations needing priority grading;

step 2: determining an initial priority function U describing the relationship between the dynamic change of the initial priority of each photovoltaic power station and the urgency of data transmission at different times_i；

And step 3: the power generation power coefficient P of each photovoltaic power station_iEnvironmental change factor η_iElectric energy quality index Z_iAnd a transmitted data accuracy index C_iAnd calculating the comprehensive initial priority coefficient K of each photovoltaic power station_iThe calculation formula is as follows:

and 4, step 4: priority dynamic change function U established by each photovoltaic power station in step 2_iAnd of the individual photovoltaic power stations in step 3Integrated initial priority coefficient K_iAnd an environmental change factor η_iEstablishing optimal dispatching distribution function Q for each photovoltaic power station_iScheduling an optimal allocation function Q_iAs shown in the following formula:

in the formula (I), the compound is shown in the specification,

the time period for realizing scheduling for the scheduling station, wherein sigma is a data transmission adjustment coefficient;

and 5: scheduling optimal distribution function Q established according to each photovoltaic power station_iThe method is characterized by uniformly scheduling data information of each photovoltaic power station, and comprises the following specific steps:

step 5.1: receiving information data sent by each photovoltaic power station and using scheduling optimal distribution function Q_iCalculating the priority of each information data;

step 5.2: setting a priority threshold value W according to historical data transmitted by each photovoltaic power station, and enabling the optimal function Q of each photovoltaic power station_iComparing the value with the value range of the priority threshold value W, and if the optimal distribution function Q of the information data of the photovoltaic power station_iIf the value is within the value range of the priority threshold value W, placing the information data of the photovoltaic power station in a high-priority sequence; if the optimal distribution function Q of the information data of the photovoltaic power station_iIf the value is smaller than the minimum value of the priority threshold value W, placing the information data of the photovoltaic power station in a low-priority sequence; if the optimal distribution function Q of the information data of the photovoltaic power station_iIf the value is larger than the maximum value of the priority threshold value W, placing the information data of the photovoltaic power station in an intermediate priority sequence;

and Y represents a priority ranking sequence, and the expression of the priority ranking sequence of the photovoltaic power station is as follows:

step 5.3: the data information of each photovoltaic power station is sorted according to priority level, so that the data information of each photovoltaic power station is uniformly scheduled;

step 2, an initial priority function U for describing the relationship between the dynamic change of the initial priority of each photovoltaic power station and the urgency of data transmission at different times of each photovoltaic power station_iThe following formula shows:

in the formula, △ t_iT is the time when all the photovoltaic power stations scheduled by the scheduling center complete data transmission for one period, α and β are attenuation factors of each photovoltaic power station with respect to time and distance respectively, 0<α<1，0<β<1；

Step 3, generating power coefficient P of each photovoltaic power station_iAccording to the actual generated power P of each photovoltaic power station_iWLight intensity I_iPhotovoltaic power conversion efficiency x_iAnd the ambient temperature T_riCalculated, the calculation formula is as follows:

wherein k is_i1、k_i2、k_i3The weighting coefficients, P, respectively reflecting the influence degrees of the illumination intensity, the photovoltaic power conversion efficiency and the ambient temperature on the ith photovoltaic power station_iNRated power generation power, P, for the ith photovoltaic power plant_iWThe calculation formula is the actual generated power of the ith photovoltaic power station and is shown as the following formula:

P_iW＝χ_iS_iI_i[1-0.0046(T_ri+18)]

in the formula, S_iThe total area of the solar panel of the ith photovoltaic power station;

step 3 of the photovoltaic power stationsEnvironmental change factor η_iAccording to the installation angle theta of the photovoltaic array of each photovoltaic power station_iConversion efficiency chi_iAtmospheric pressure q_iAmbient temperature T_riAnd average temperature T of photovoltaic panel_biAnd calculating according to the following formula:

wherein, η_iIs the environmental change factor of the ith photovoltaic power plant.

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