CN118313136A - Marine wind power submarine cable section selection optimization method based on insulation thermal fatigue life modeling - Google Patents

Abstract

The application relates to the technical field of cable transmission, and provides a marine wind power submarine cable section model selection optimization method based on insulation thermal fatigue life modeling. The method comprises the following steps: inputting the annual power generation capacity time sequence and the seabed temperature time sequence into a thermoelectric equivalent model to obtain instantaneous conductor temperature sequences of submarine cables with different section sizes; determining a corresponding maximum instantaneous conductor temperature in the instantaneous conductor temperature sequence of the submarine cable of each section size; obtaining estimated service lives of submarine cables with different section sizes based on the insulating thermal fatigue life model; under the constraint that the estimated service life of the submarine cable running under a given time window is not lower than a service life set value, the maximum instantaneous conductor temperature is not higher than a temperature set value and the submarine cable power is not higher than the constraint condition of the system stability limit power, the target section size of the submarine cable which enables the leveling degree electric cost function to be minimum is obtained. The submarine cable section selected by the method has low power generation cost.

Description

Marine wind power submarine cable section selection optimization method based on insulation thermal fatigue life modeling

Technical Field

The application relates to the technical field of cable transmission, in particular to a marine wind power submarine cable section selection optimization method, a device, computer equipment, a storage medium and a computer program product based on insulation thermal fatigue life modeling.

Background

The operation lever value of the offshore wind power project is large, the submarine cable is a power system component responsible for transmitting produced power to the shore, and if single-point faults occur, the power output of the offshore booster station is influenced, so that the reliability of the whole wind power plant is obviously influenced. Therefore, it is necessary to select the submarine cable to ensure that the submarine cable can adapt to specific project requirements and submarine environment conditions, and ensure the stability and reliability of power transmission.

One method of the existing submarine cable section model selection method of the offshore wind power project is a probability method for estimating the exceeding of the cable temperature in different time ranges, and the other method is a method for deducing an equivalent cyclic load curve from a wind speed time sequence.

However, the implicit certainty and constant rated power operation assumption of the submarine cable section selection method of the existing offshore wind power project are too conservative, and the power generation cost of the selected submarine cable section is high.

Disclosure of Invention

Based on the above, it is necessary to provide a method, a device, a computer readable storage medium and a computer program product for optimizing the cross section profile of a submarine wind power submarine cable based on insulation thermal fatigue life modeling.

In a first aspect, the application provides a marine wind power submarine cable section model selection optimization method based on insulation thermal fatigue life modeling, which comprises the following steps:

Inputting available annual power generation capacity time sequences and seabed temperature time sequences of submarine cables with different section sizes into a pre-constructed thermoelectric equivalent model to obtain instantaneous conductor temperature sequences of the submarine cables with different section sizes;

Determining the maximum instantaneous conductor temperature of each section-size submarine cable in an instantaneous conductor temperature sequence of each section-size submarine cable;

Obtaining estimated service lives of the submarine cables with different section sizes based on an insulating thermal fatigue service life model;

Under the constraint that the estimated service life of the submarine cable running under a given time window is not lower than a service life set value, the maximum instantaneous conductor temperature of the submarine cable is not higher than a temperature set value and the submarine cable power is not higher than the constraint condition of the system stability limit power, the target section size of the submarine cable which enables the leveling degree electric cost function to be minimum is obtained.

In one embodiment, before obtaining the estimated life of the submarine cable with different cross-sectional dimensions based on the thermal fatigue life model, the method further comprises:

Obtaining a probability life estimation model according to the aging life model and the Weber probability density function;

And applying a probability amplification law to the probability life estimation model to obtain the insulating thermal fatigue life model.

In one embodiment, the applying the probability amplification law to the probability life estimation model to obtain the thermal fatigue life model includes:

determining an expansion coefficient according to the section size and the length of the submarine cable and the proportion of the radius of the conductor;

and applying a probability amplification law to the probability life estimation model according to the amplification coefficient to obtain the insulating thermal fatigue life model.

In one embodiment, the obtaining the estimated life of the submarine cable with different section sizes according to the thermal fatigue life insulation model includes:

Obtaining the probability failure life of the submarine cables with different section sizes according to the insulation thermal fatigue life model;

integrating the probability failure life of the submarine cables with different section sizes along a set time period to obtain life loss fractions corresponding to the set time periods;

And obtaining the estimated service life of the submarine cable with different section sizes according to the service life loss fraction corresponding to each set time period.

In one embodiment, the obtaining the estimated life of the submarine cable with different section sizes according to the life loss score corresponding to each set time period includes:

adding the life loss scores of each set time period to obtain a score adding result;

When the score addition result is equal to a set value, adding all set time periods to obtain a time period addition result;

and obtaining the estimated service lives of the submarine cables with different section sizes according to the addition result of the time periods.

In one embodiment, the obtaining the target cross-sectional dimension of the submarine cable for minimizing the leveling electric cost function under the constraint that the estimated life of the submarine cable running in the given time window is not lower than the life set value, the maximum instantaneous conductor temperature is not higher than the temperature set value, and the submarine cable power is not higher than the system stability limit power comprises:

Substituting the maximum instantaneous conductor temperature and the estimated service life of the submarine cables with different cross-section sizes into a leveling degree electric cost function to obtain leveling degree electric cost function values corresponding to the submarine cables with different cross-section sizes;

Removing the electrical cost function value of the leveling degree corresponding to the submarine cable which does not meet the constraint condition, and obtaining a removed electrical cost function value set of the leveling degree;

and taking the section size of the submarine cable corresponding to the minimum value in the leveling degree electric cost function value set as a target section size.

In a second aspect, the application also provides a marine wind power submarine cable section selection optimizing device based on insulation thermal fatigue life modeling, which comprises:

The temperature sequence acquisition module is used for inputting the available annual power generation capacity time sequence and the seabed temperature time sequence of the submarine cables with different section sizes into a thermoelectric equivalent model constructed in advance to obtain the instantaneous conductor temperature sequences of the submarine cables with different section sizes;

The maximum temperature acquisition module is used for determining the maximum instantaneous conductor temperature of the submarine cable with each section size in the instantaneous conductor temperature sequence of the submarine cable with each section size;

the estimated life acquisition module is used for acquiring the estimated life of the submarine cable with different section sizes based on the insulating thermal fatigue life model;

The target section size acquisition module is used for obtaining the target section size of the submarine cable, wherein the target section size of the submarine cable is used for enabling the leveling degree electric cost function to be minimum under the constraint conditions that the estimated service life of the submarine cable running in a given time window is not lower than a service life set value, the maximum instantaneous conductor temperature of the submarine cable is not higher than a temperature set value and the power of the submarine cable is not higher than the system stability limit power.

In a third aspect, the present application also provides a computer device. The computer device comprises a memory storing a computer program and a processor executing the method described above.

In a fourth aspect, the present application also provides a computer-readable storage medium. The computer readable storage medium has stored thereon a computer program which is executed by a processor to perform the above method.

In a fifth aspect, the present application also provides a computer program product. The computer program product comprises a computer program which is executed by a processor to perform the above method.

According to the marine wind power submarine cable section model selection optimization method, device, computer equipment, storage medium and computer program product based on insulation thermal fatigue life modeling, the available annual power generation capacity time sequence and the seabed temperature time sequence of submarine cables with different section sizes are input into a thermoelectric equivalent model constructed in advance, and the instantaneous conductor temperature sequences of submarine cables with different section sizes are obtained; determining a maximum instantaneous conductor temperature of the submarine cable of each cross-sectional dimension in the instantaneous conductor temperature sequence of the submarine cable of each cross-sectional dimension; obtaining estimated service lives of submarine cables with different section sizes based on the insulating thermal fatigue life model; under the constraint that the estimated service life of the submarine cable running under a given time window is not lower than a service life set value, the maximum instantaneous conductor temperature of the submarine cable is not higher than a temperature set value and the submarine cable power is not higher than the constraint condition of the system stability limit power, the target section size of the submarine cable which enables the leveling degree electric cost function to be minimum is obtained. The scheme considers the estimated service life of the submarine cable, the maximum instantaneous conductor temperature of the submarine cable and the submarine cable power when selecting the cross section size of the submarine cable, the estimated service life of the submarine cable running in a given time window is not lower than a service life set value, the maximum instantaneous conductor temperature of the submarine cable is not higher than a temperature set value, the submarine cable power is not higher than the constraint condition of the system stability limit power, the cross section size of the submarine cable with the minimum electrical cost of the leveling degree is obtained based on the electrical cost function of the leveling degree under the constraint condition that the electrical cost of the submarine cable is not higher than the constraint condition of the system stability limit power, and the power generation cost of the selected submarine cable cross section is lower.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the related art, the drawings that are required to be used in the embodiments or the related technical descriptions will be briefly described, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

FIG. 1 is an application environment diagram of a marine wind power submarine cable section selection optimization method based on insulation thermal fatigue life modeling in one embodiment;

FIG. 2 is a schematic flow chart of a method for optimizing cross section selection of a submarine wind power submarine cable based on insulation thermal fatigue life modeling in one embodiment;

FIG. 3 is a schematic diagram of wind farm annual load considering worst case scenario;

FIG. 4 is a graph of the annual maximum operating temperature profile of a submarine cable of different cross-sectional dimensions;

FIG. 5 is a life distribution diagram of submarine cables of different cross-sectional dimensions;

FIG. 6 is a graph of electrical costs for different cross-sectional sizes of submarine cables and their corresponding levels;

FIG. 7 is a block diagram of a marine wind power submarine cable section profile optimization device based on insulation thermal fatigue life modeling in one embodiment;

Fig. 8 is an internal structural diagram of a computer device in one embodiment.

Detailed Description

The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the described embodiments of the application may be combined with other embodiments.

The embodiment of the application provides a marine wind power submarine cable section model selection optimization method based on insulation thermal fatigue life modeling, which can be executed by computer equipment, as shown in figure 1, the computer equipment can acquire available annual power generation capacity time sequences and seabed temperature time sequences of submarine cables with different section sizes, and the annual power generation capacity time sequences and the seabed temperature time sequences are input into a thermoelectric equivalent model constructed in advance to obtain instantaneous conductor temperature sequences of submarine cables with different section sizes; determining a maximum instantaneous conductor temperature of the submarine cable of each cross-sectional dimension in the instantaneous conductor temperature sequence of the submarine cable of each cross-sectional dimension; obtaining estimated service lives of submarine cables with different section sizes based on the insulating thermal fatigue life model; under the constraint that the estimated service life of the submarine cable running under a given time window is not lower than a service life set value, the maximum instantaneous conductor temperature of the submarine cable is not higher than a temperature set value and the submarine cable power is not higher than the constraint condition of the system stability limit power, the target section size of the submarine cable which enables the leveling degree electric cost function to be minimum is obtained. It will be appreciated that the computer device may be implemented by a server, a terminal, or an interactive system between the terminal and the server. In this embodiment, the method includes the steps shown in fig. 2:

and S201, inputting the available annual power generation capacity time sequence and the seabed temperature time sequence of the submarine cables with different section sizes into a thermoelectric equivalent model constructed in advance to obtain the instantaneous conductor temperature sequences of the submarine cables with different section sizes.

Prior to step S201, main simulation parameters may be defined, which may include: a) Submarine cable design information: the submarine cable design life, fault probability and design length; b) Submarine cable alternative model and c) submarine cable structural parameters. Related item data sets may also be collected first, which may include: installation capacity, rated voltage and system rated frequency of the offshore wind farm, and wind farm power factor and series-parallel compensation conditions.

In addition, it is also necessary to define the laying conditions of the submarine cable, which include: total length, burial depth and lay pitch. Soil information of the seabed is also required to be collected, and the method specifically comprises the following steps: i) Thermal resistance, and j) specific heat. The information related to the seabed is assumed to be spatially uniform over the submarine cable path.

The natural years may be chosen as a unit analysis time window, on the one hand because natural years are typical time frames for calculating cash flow on hand, and are also common periods of economic indicators in fund plans that quantify project performance, such as net present values, normalized power costs, and internal profitability. On the other hand, the natural year time window is selected to cover the climate conditions and source load characteristics of four seasons, and the most unfavorable operation condition of the submarine cable is included.

The method comprises the steps of taking a natural year as a unit analysis time window, predicting the future available annual power generation capacity of the submarine cable with any section size, predicting power generation capacity data of the submarine cable with any section size at different time periods of each year, and collecting the power generation capacity data of different time periods in one year according to time to obtain a power generation capacity time sequence of the year，Collecting power generation capacity data of a plurality of natural years according to time to obtain available annual power generation capacity time sequence of submarine cable with any section sizeWhere N represents the size of the collection.

The method can create a synthetic seabed temperature time sequence based on meteorological data of the seabed cable, take natural years as unit analysis time windows, predict seabed temperature data of the seabed cable at the time point in different time periods of each year, and time and assemble the seabed temperature data in different time periods in one year to obtain the seabed temperature time sequence of the year，And (3) collecting the seabed temperature data of a plurality of natural years according to time to obtain a seabed temperature time sequence T= { T ₁,…,T_N } of the seabed cable, wherein N represents the size of the collection.

Annual power generation capacity time series can be established(Power Generation Capacity time series of n years), seabed temperature time series(Seabed temperature time series of n years) and cross section size of submarine cable form a tripletWhere c is the type of submarine cable cross-sectional dimensions. Each triplet can calculate peak temperature time sequence based on thermoelectric equivalent modelWhereinIs the firstAnnual submarine cableInstantaneous peak conductor temperature at hot spots, e.g.WhereinIs thatAndIs a number of elements of (a). And (3) collecting the calculated peak temperature time sequences of a plurality of natural years according to time to obtain the instantaneous conductor temperature sequence of the submarine cable c.

Step S202, determining the maximum instantaneous conductor temperature of the submarine cable of each cross-section size in the instantaneous conductor temperature sequence of the submarine cable of each cross-section size.

Determining the maximum instantaneous conductor temperature of the instantaneous conductor temperature sequence as the maximum instantaneous conductor temperature of the submarine cable c in the instantaneous conductor temperature sequence of the submarine cable c with any section sizeAs shown in formula (1).

（1）

And step S203, obtaining estimated service lives of submarine cables with different section sizes based on the insulating thermal fatigue service life model.

The estimated service life of submarine cables with different section sizes can be obtained according to the insulating thermal fatigue service life model.

Step S204, obtaining the target section size of the submarine cable which enables the leveling degree electric cost function to be minimum under the constraint that the estimated service life of the submarine cable running in a given time window is not lower than a service life set value, the maximum instantaneous conductor temperature of the submarine cable is not higher than a temperature set value and the submarine cable power is not higher than the constraint condition of the system stability limit power.

Setting up、、、Parameters of offshore wind farm installation capacity (MW), line stable delivery power limit (MW), maximum instantaneous conductor temperature allowed (DEG C), and submarine cable design life (years) are shown, respectively. In addition, the setting is thatRespectively for representing submarine cablesIn a given time windowMedium relative IEC calculated ratingPower increase coefficient of (d) cableMaximum instantaneous conductor temperature (DEG C) and a given time windowIs a cable of (2)Life (years) of the calculation.

The constraint that the estimated lifetime of the submarine cable operating under a given time window is not lower than the lifetime set point may be expressed as formula (2), the constraint that the maximum instantaneous conductor temperature of the submarine cable does not exceed the temperature set point may be expressed as formula (3), and the constraint that the submarine cable power does not exceed the system stability limit power may be expressed as formula (4).

（2）

（3）

（4）

Wherein the method comprises the steps of

（5）

Wherein the method comprises the steps ofIs the line voltage at which the voltage is to be applied,Is the submarine cable impedance from the offshore power generation end to the onshore power receiving end,Representing submarine cablesIs an active loss of itself.

Leveling electrical cost function for representing leveling electrical cost (LCOE) index of submarine cable, which levels electrical cost to cost and generate power in submarine cable infrastructure life cycle according to discount rateAfter the discount, the power generation cost per unit electric quantity caused by the submarine cable can be calculated, and the mathematical form is shown as a formula (6), which has the meaning of selecting the submarine cable typeRun the firstAnd (5) leveling degree and electric cost index of the submarine cable in the year.Is the cost over the submarine cable infrastructure lifecycle (ten thousand yuan/km), its lay cost is determined by the submarine cable routing, regardless of the submarine cable cross section, so the lay cost is ignored, but the submarine cable loss cost is contained in the flatness electrical cost function.

（6）

Representing the total length of the cable (km), r is the rate of failure (assuming 5%),Is the life of the project (say 25 years),Is the operation ofAnnual submarine cable typeAnnual capacity (MWh) of power loss is considered.

While the leveling electrical cost function and constraints are generic, the leveling electrical cost function and constraints will be tailored to the particular offshore wind farm based on input data sets including: specified offshore wind farm generating potential, i.e., annual generating capacity time seriesTime series of seabed temperatureSpecific soil thermal properties, electrical operating conditions and cable installation conditions. Under the constraint of the constraint condition, the safety operation constraint can be complied with in the process of generating electricity by using the submarine cable with the target section size.

According to the marine wind power submarine cable section model selection optimization method based on insulation thermal fatigue life modeling, the estimated life of the submarine cable, the maximum instantaneous conductor temperature of the submarine cable and the submarine cable power are considered when the section size of the submarine cable is selected, the estimated life of the submarine cable running in a given time window is not lower than a life set value, the maximum instantaneous conductor temperature of the submarine cable does not exceed a temperature set value, the submarine cable power does not exceed the constraint condition of the system stability limit power and is based on the leveling degree electric cost function, the submarine cable section size with the minimum leveling degree electric cost is obtained, and the power generation cost of the selected submarine cable section is lower.

In one embodiment, before obtaining the estimated life of the submarine cable with different section sizes based on the insulating thermal fatigue life model, the method provided by the application further comprises the following steps: obtaining a probability life estimation model according to the aging life model and the Weber probability density function; and applying a probability amplification law to the probability life estimation model to obtain an insulation thermal fatigue life model of the insulation thermal fatigue life model.

Many different models can be used to infer the long-term aging life of submarine cable insulation, such as Zu Erke f (Zurkov) model, crine model, and Arrhenius (Arrhenius) model, each of which relates failure time to failure rate based on probability. All of these models present different analytical expressions and parameter values, but in general, these models are able to provide similar conclusions about the insulation life of the submarine cable.

For certain crosslinked polyethylene insulated power cables (XLPE cables), the polyethylene base raw material product cannot be tightly combined with the requirements of high-voltage cable material manufacturers, so that the quality of the high-voltage cable material does not meet certain requirements, the thermal aging life of the crosslinked polyethylene insulated power cable insulating material can be evaluated, and an aging life model suitable for the high-voltage cable is obtained through an acceleration experiment, as shown in a formula (7).

（7）

Wherein the method comprises the steps ofIs a cableIs used for the insulation life of the steel wire,Is the firstYear, cable typeDuring a time periodIs set, the conductor temperature (K) of the conductor (C). The aging life model does not take into account the effects of electrical aging. For any type of submarine cable, the operation condition is guaranteed to be near the rated voltage, and the electric field strength of the submarine cable can be considered as that the cable load has larger fluctuationMaintaining the rating unchanged, the electrical aging factor is already covered in its design life, without any consideration of its fluctuation effect on life.

The most widely accepted cumulative probability density function for correlating failure time with failure probability for high voltage devices is the weber probability density function, as shown in equation (8).

（8）

Wherein the method comprises the steps ofIs at failure probabilityThe lifetime of the product is reduced,Is the scaling factor of the probability density function,Is thatIs a function of (2)Is a shape parameter of the probability density function.

Substituting the aging life model into the Weber probability density function to obtain a probability life estimation model, wherein the probability life estimation model is shown in a formula (9).

（9）

The probabilistic life estimation model simulates operating conditions in a set of operating conditionsProbability of failureAnd (3) the probability failure life of the cable. However, the probabilistic life estimation model is only suitable for the case of small Duan Dingchang cable test, in order to extrapolate the result to the actual length of the cable, the probabilistic amplification law may be applied to the probabilistic life estimation model, as shown in equation (10), and the probabilistic life estimation model form (9) may be substituted into equation (10), so that the insulating thermal fatigue life model may be obtained, as shown in equation (11).

（10）

Wherein the method comprises the steps ofIs the probability of failure of the full length of the cable,To expand the coefficients.

（11）

Wherein the method comprises the steps ofThe value is taken as 2 and other parameters are available from the submarine cable manufacturer.

According to the insulation thermal fatigue life model, the estimated life of submarine cables with different section sizes can be obtained.

In the embodiment, a probability life estimation model is obtained according to an aging life model and a Weber probability density function; applying a probability amplification law to the probability life estimation model to obtain an insulating thermal fatigue life model; according to the insulation thermal fatigue life model, the estimated life of submarine cables with different section sizes is obtained, and the problem of life estimation of the submarine cables is solved.

In one embodiment, a probability amplification law is applied to the probability life estimation model to obtain an insulating thermal fatigue life model, and the specific steps are as follows: determining an expansion coefficient according to the section size and the length of the submarine cable and the proportion of the radius of the conductor; and according to the expansion coefficient, applying a probability amplification law to the probability life estimation model to obtain the insulating thermal fatigue life model.

The expansion coefficient may be determined according to the cross-sectional size and length of the submarine cable and the ratio of the conductor radius, as shown in formula (12).

（12）

And according to the expansion coefficient, applying a probability amplification law to the probability life estimation model to obtain the insulating thermal fatigue life model.

In the embodiment, the expansion coefficient is determined according to the section size and length of the submarine cable and the proportion of the conductor radius; and according to the expansion coefficient, applying a probability amplification law to the probability life estimation model to obtain an insulating thermal fatigue life model, and being suitable for life estimation of submarine cables with actual lengths.

In one embodiment, according to the thermal fatigue life model, the estimated life of submarine cables with different section sizes is obtained, and the specific steps are as follows: obtaining the probability failure life of submarine cables with different section sizes according to the insulation thermal fatigue life model; integrating the probability failure life of the submarine cables with different section sizes along the set time periods to obtain the life loss fraction corresponding to each set time period; and obtaining estimated service lives of the submarine cables with different section sizes according to the service life loss fractions corresponding to the set time periods.

According to the insulation thermal fatigue life model, the submarine cable can be obtainedProbability of failure life of (a)Is provided withTo generate power capacity time series in the yearIn a set time period ofAn infinitely small time increment in the submarine cableProbability of failure life of (a)Along a set period of timeIntegrating the time period to obtain the set time periodAs shown in formula (13).

（13）

According to the above method, the life loss score corresponding to each set period can be obtained. According to the life loss fraction corresponding to each set time period, the estimated life of the submarine cable with different section sizes can be obtained.

In the embodiment, the probability failure life of submarine cables with different section sizes is integrated along a set time period, so that the life loss fraction corresponding to each set time period is obtained; according to the life loss fraction corresponding to each set time period, the estimated life of the submarine cable with different section sizes can be obtained.

In one embodiment, according to the life loss fraction corresponding to each set time period, the estimated life of the submarine cable with different section sizes is obtained, and the specific steps are as follows: adding the life loss scores of each set time period to obtain a score adding result; when the score addition result is equal to the set value, adding each set time period to obtain a time period addition result; and obtaining the estimated service lives of the submarine cables with different section sizes according to the time period addition result.

According to the Pelmgren-Michaer (Palmgren-Miner) accumulated damage theory, the life loss fractions of each time period are added, and when the result is equal to one, the damage is accumulated to a critical value, so that the estimated life of the insulation, in which fatigue failure occurs, is reached. Therefore, the set value can be set to 1.

Adding the life loss fractions of the submarine cables with any section size in each set time period to obtain a fraction adding result; when the score addition result is equal to 1, adding the set time periods to obtain a time period addition result, and taking the time period addition result as the estimated service life of the submarine cable with the section size.

Submarine cable was calculated by (14)Is equal to the estimated life of (a)Years), may also be referred to as a number of failure cycles.

（14）

In this embodiment, the estimated life of the submarine cable with different section sizes is obtained according to the result of the fractional addition of the life loss fraction of each set time period.

In one embodiment, the target cross-sectional dimension of the submarine cable, which minimizes the leveling electric cost function, is obtained under the constraint that the estimated service life of the submarine cable running in a given time window is not lower than a service life set value, the maximum instantaneous conductor temperature is not higher than a temperature set value, and the submarine cable power is not higher than the system stability limit power, and the specific steps are as follows: substituting the maximum instantaneous conductor temperature and the estimated service life of the submarine cables with different cross-section sizes into a leveling degree electric cost function to obtain the leveling degree electric cost function values of the submarine cables with different cross-section sizes; removing the electrical cost function value of the leveling degree corresponding to the submarine cable which does not meet the constraint condition, and obtaining a removed electrical cost function value set of the leveling degree; and taking the section size of the submarine cable corresponding to the minimum value in the leveling degree electric cost function value set as a target section size.

The constraint-based flatness electrical cost function is nonlinear. However, because of the limited number of types of submarine cables provided by manufacturers, the solution search space is relatively small, which allows the selection of a submarine cable section size model that meets constraints using a simple exhaustive optimization method.

In this embodiment, a simple exhaustive optimization method is used to obtain the electrical cost function value of the leveling degree of the submarine cables with different section sizes, and the target section size is determined according to the constraint condition.

The application can take a certain offshore wind power project as a case research object. According to the pre-feasibility study, the project had a total installed capacity of 600 megawatts, a single wind turbine of 5.5 megawatts, a total length of outlet cable of 35 km, a nominal voltage of 220 kv, a nominal frequency of 50 hz, and no compensation unit.

The input data about the submarine cable is provided by the offshore wind project, and the main data are detailed in table 1. Due to the lack of data for the seafloor temperature time series (which may also be referred to as the sea-low temperature time series), a synthetic seafloor temperature time series may be created based on meteorological data for the location of the submarine cable. The time series of seabed temperature variations ranges from 16 ℃ to 25 ℃ and takes into account seasonal fluctuations.

TABLE 1 submarine cable laying-related simulation data for offshore wind project

The simulation data of the 25-year offshore wind power generation capacity time sequence can be analyzed, and the model selection result is compared with the model selection result of a common method of a design unit in evaluating the model selection of the submarine cable. The usual method of designing units in evaluating submarine cable type selection comprises only one multi-parameter static equation for calculating continuous current transmitted over an infinite period of timeThe conductor temperature was kept constant at 90 ℃. Then select oneSmaller cables having values equal to or greater than the total current (including capacitive current) at the hot spot. The result of the selection using this method is a submarine cable of 1000 square millimeters.

When the submarine cable is selected by adopting the submarine wind power submarine cable section selection optimization method based on insulation thermal fatigue life modeling, preprocessing analysis is needed to be carried out on the power generation capacity time sequence data, and a representative period set is found out. Taking the natural seasonal periodicity of wind power into consideration, selecting a period according to years (365 days) to capture a most representative multi-wind daily load data window in multi-wind years; the preconditioning current is derived by calculating the RMS value of the entire multi-year dataset over time, and then obtaining the year at which the calculated RMS value is greatest over the year period. After applying the above procedure to the present study, the worst case load pattern diagram is shown in fig. 3. This stepwise mode is per-unit with respect to the total current at the hot spot.

By using the mode in FIG. 3 and considering the synthesized seabed temperature time sequence, the offshore wind power submarine cable section model selection optimization method based on insulation thermal fatigue life modeling provided by the application is applied, the model selection result is 630 square millimeter submarine cable, and the peak temperature of the 630 square millimeter submarine cableIs 87.3 ℃. When using the complete time data set, all of them are composed ofPeak temperature of defined pointShown in fig. 4.

The results show that all but 500 square millimeters of submarine cables meet the constraint (3), i.e. do not exceed the rated temperature limit (indicated by the blue dashed line). Based on the submarine cable heating results, the submarine cable with the result of 630 square millimeters or the submarine cable with the result of 800 square millimeters is selected.

From a lifetime estimation perspective, different instantaneous temperature profiles result in different lifetime estimates, as shown in fig. 5. The lifetime estimate is given as the ratio of calculated value to design value. As expected, 630 square millimeters of submarine cable exhibited a life ratio that exceeded the optimized model limits due to exposure to more severe conductor temperatures. In contrast, an 800 mm square submarine cable satisfies this constraint for all simulated annual periods, while satisfying all other constraints. Selected 800 square millimeter submarine cableThe mean and standard deviation of (2) are 0.58 and 0.08, respectively. For the followingThese values are 74.5 ℃ and 0.88, respectively. The standard deviation of these two variables is acceptable, indicating robustness to different annual profiles.

Different submarine cables are arranged onThe concentration difference in this can be explained based on the following facts: larger submarine cables have a larger time constant (slower dynamic response) and therefore the reaction rate due to power variation is less pronounced than smaller submarine cables. Nevertheless, optimizing from 1000 square millimeters of submarine cable based on the IEC standard to 800 square millimeters of submarine cable directly results in a reduction of initial investment, but also in an increase of total power loss. Therefore, the comprehensive calculation of the electrical cost index of the leveling degree can comprehensively evaluate the validity of the optimization result, and the evaluation result is shown in fig. 6. The results show that the flatness electrical cost function increases monotonically with the use of larger submarine cables, so it can be concluded that the smaller the submarine cable cross section, the smaller the flatness electrical cost function value.

It should be understood that, although the steps in the flowcharts related to the embodiments described above are sequentially shown as indicated by arrows, these steps are not necessarily sequentially performed in the order indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least some of the steps in the flowcharts described in the above embodiments may include a plurality of steps or a plurality of stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of the steps or stages is not necessarily performed sequentially, but may be performed alternately or alternately with at least some of the other steps or stages.

Based on the same inventive concept, the embodiment of the application also provides a marine wind power submarine cable section type selection optimizing device based on insulation thermal fatigue life modeling, which is used for realizing the above-mentioned marine wind power submarine cable section type selection optimizing method based on insulation thermal fatigue life modeling. The implementation scheme of the device for solving the problems is similar to the implementation scheme recorded in the method, so the specific limitation in the embodiment of the device for optimizing the cross section of the offshore wind power submarine cable based on the insulation thermal fatigue life modeling provided below can be referred to the limitation of the method for optimizing the cross section of the offshore wind power submarine cable based on the insulation thermal fatigue life modeling, and the description is omitted here.

In an exemplary embodiment, as shown in fig. 7, there is provided a marine wind power submarine cable section model selection optimizing device based on insulation thermal fatigue life modeling, wherein:

the temperature sequence acquisition module 701 is configured to input an available annual power generation capacity time sequence and a seabed temperature time sequence of submarine cables with different cross-section sizes into a thermoelectric equivalent model constructed in advance, so as to obtain instantaneous conductor temperature sequences of submarine cables with different cross-section sizes;

A maximum temperature obtaining module 702, configured to determine, in a sequence of instantaneous conductor temperatures of the submarine cable of each cross-section size, a maximum instantaneous conductor temperature of the submarine cable of each cross-section size;

the estimated life obtaining module 703 is configured to obtain estimated life of the submarine cable with different cross-sectional dimensions based on the thermal fatigue life model;

The target cross-section size obtaining module 704 is configured to obtain a target cross-section size of the submarine cable that minimizes the leveling electric cost function under the constraint that the estimated lifetime of the submarine cable running in the given time window is not less than the lifetime set value, the maximum instantaneous conductor temperature is not more than the temperature set value, and the submarine cable power is not more than the constraint condition of the system stability limit power.

In one embodiment, the estimated lifetime acquisition module 703 is further configured to: obtaining a probability life estimation model according to the aging life model and the Weber probability density function; and applying a probability amplification law to the probability life estimation model to obtain the insulating thermal fatigue life model.

In one embodiment, the estimated lifetime acquisition module 703 is further configured to: determining an expansion coefficient according to the section size and the length of the submarine cable and the proportion of the radius of the conductor; and applying a probability amplification law to the probability life estimation model according to the amplification coefficient to obtain the insulating thermal fatigue life model.

In one embodiment, the estimated lifetime acquisition module 703 is further configured to: obtaining the probability failure life of the submarine cables with different section sizes according to the insulation thermal fatigue life model; integrating the probability failure life of the submarine cables with different section sizes along a set time period to obtain life loss fractions corresponding to the set time periods; and obtaining the estimated service life of the submarine cable with different section sizes according to the service life loss fraction corresponding to each set time period.

In one embodiment, the estimated lifetime acquisition module 703 is further configured to: adding the life loss scores of each set time period to obtain a score adding result; when the score addition result is equal to a set value, adding all set time periods to obtain a time period addition result; and obtaining the estimated service lives of the submarine cables with different section sizes according to the addition result of the time periods.

In one embodiment, the target cross-sectional dimension acquisition module 704 is further configured to: substituting the maximum instantaneous conductor temperature and the estimated service life of the submarine cables with different cross-section sizes into a leveling degree electric cost function to obtain the leveling degree electric cost function values of the submarine cables with different cross-section sizes; removing the electrical cost function value of the leveling degree corresponding to the submarine cable which does not meet the constraint condition, and obtaining a removed electrical cost function value set of the leveling degree; and taking the section size of the submarine cable corresponding to the minimum value in the leveling degree electric cost function value set as a target section size.

The above-mentioned marine wind power submarine cable section selection optimizing device based on insulation thermal fatigue life modeling can be realized by all or part of software, hardware and combination thereof. The above modules may be embedded in hardware or may be independent of a processor in the computer device, or may be stored in software in a memory in the computer device, so that the processor may call and execute operations corresponding to the above modules.

In one exemplary embodiment, a computer device is provided, which may be a server, and the internal structure thereof may be as shown in fig. 8. The computer device includes a processor, a memory, an Input/Output interface (I/O) and a communication interface. The processor, the memory and the input/output interface are connected through a system bus, and the communication interface is connected to the system bus through the input/output interface. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The database of the computer equipment is used for storing data of the marine wind power submarine cable section model selection optimization method based on insulation thermal fatigue life modeling. The input/output interface of the computer device is used to exchange information between the processor and the external device. The communication interface of the computer device is used for communicating with an external terminal through a network connection. The computer program is executed by a processor to realize a marine wind power submarine cable section model selection optimization method based on insulation thermal fatigue life modeling.

It will be appreciated by those skilled in the art that the structure shown in FIG. 8 is merely a block diagram of some of the structures associated with the present inventive arrangements and is not limiting of the computer device to which the present inventive arrangements may be applied, and that a particular computer device may include more or fewer components than shown, or may combine some of the components, or have a different arrangement of components.

In an embodiment, there is also provided a computer device comprising a memory and a processor, the memory having stored therein a computer program, the processor implementing the steps of the method embodiments described above when the computer program is executed.

In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored which, when executed by a processor, carries out the steps of the method embodiments described above.

In an embodiment, a computer program product is provided, comprising a computer program which, when executed by a processor, implements the steps of the method embodiments described above.

It should be noted that, the user information (including but not limited to user equipment information, user personal information, etc.) and the data (including but not limited to data for analysis, stored data, presented data, etc.) related to the present application are both information and data authorized by the user or sufficiently authorized by each party, and the collection, use and processing of the related data are required to meet the related regulations.

Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, database, or other medium used in embodiments provided herein may include at least one of non-volatile and volatile memory. The nonvolatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical Memory, high density embedded nonvolatile Memory, resistive random access Memory (ReRAM), magneto-resistive random access Memory (Magnetoresistive Random Access Memory, MRAM), ferroelectric Memory (Ferroelectric Random Access Memory, FRAM), phase change Memory (PHASE CHANGE Memory, PCM), graphene Memory, and the like. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory, and the like. By way of illustration, and not limitation, RAM can be in various forms such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), etc. The databases referred to in the embodiments provided herein may include at least one of a relational database and a non-relational database. The non-relational database may include, but is not limited to, a blockchain-based distributed database, and the like. The processor referred to in the embodiments provided in the present application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, or the like, but is not limited thereto.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing examples illustrate only a few embodiments of the application and are described in detail herein without thereby limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of the application should be assessed as that of the appended claims.

Claims (10)

1. An offshore wind power submarine cable section model selection optimization method based on insulation thermal fatigue life modeling is characterized by comprising the following steps:

Inputting available annual power generation capacity time sequences and seabed temperature time sequences of submarine cables with different section sizes into a pre-constructed thermoelectric equivalent model to obtain instantaneous conductor temperature sequences of the submarine cables with different section sizes;

Determining the maximum instantaneous conductor temperature of each section-size submarine cable in an instantaneous conductor temperature sequence of each section-size submarine cable;

Obtaining estimated service lives of the submarine cables with different section sizes based on an insulating thermal fatigue service life model;

Under the constraint that the estimated service life of the submarine cable running under a given time window is not lower than a service life set value, the maximum instantaneous conductor temperature of the submarine cable is not higher than a temperature set value and the submarine cable power is not higher than the constraint condition of the system stability limit power, the target section size of the submarine cable which enables the leveling degree electric cost function to be minimum is obtained.

2. The method of claim 1, wherein prior to deriving the estimated life of the different cross-sectional dimensions of the submarine cable based on the insulating thermal fatigue life model, the method further comprises:

Obtaining a probability life estimation model according to the aging life model and the Weber probability density function;

And applying a probability amplification law to the probability life estimation model to obtain the insulating thermal fatigue life model.

3. The method of claim 2, wherein applying the probabilistic amplification law to the probabilistic life estimation model results in the thermal fatigue life model comprising:

determining an expansion coefficient according to the section size and the length of the submarine cable and the proportion of the radius of the conductor;

and applying a probability amplification law to the probability life estimation model according to the amplification coefficient to obtain the insulating thermal fatigue life model.

4. The method according to claim 1, wherein the obtaining the estimated life of the submarine cables of different cross-sectional dimensions based on the thermal fatigue life model comprises:

Obtaining the probability failure life of the submarine cables with different section sizes according to the insulation thermal fatigue life model;

integrating the probability failure life of the submarine cables with different section sizes along a set time period to obtain life loss fractions corresponding to the set time periods;

And obtaining the estimated service life of the submarine cable with different section sizes according to the service life loss fraction corresponding to each set time period.

5. The method according to claim 4, wherein obtaining the estimated life of the submarine cable with different cross-sectional dimensions according to the life loss score corresponding to each set time period comprises:

adding the life loss scores of each set time period to obtain a score adding result;

When the score addition result is equal to a set value, adding all set time periods to obtain a time period addition result;

and obtaining the estimated service lives of the submarine cables with different section sizes according to the addition result of the time periods.

6. The method of claim 1, wherein obtaining the target cross-sectional dimension of the submarine cable that minimizes the electrical cost function of leveling under the constraint that the estimated lifetime of the submarine cable operating at the given time window is not less than the lifetime setpoint, the maximum instantaneous conductor temperature of the submarine cable is not greater than the temperature setpoint, and the submarine cable power is not greater than the system stability limit power, comprises:

Substituting the maximum instantaneous conductor temperature and the estimated service life of the submarine cables with different cross-section sizes into a leveling degree electric cost function to obtain leveling degree electric cost function values corresponding to the submarine cables with different cross-section sizes;

Removing the electrical cost function value of the leveling degree corresponding to the submarine cable which does not meet the constraint condition, and obtaining a removed electrical cost function value set of the leveling degree;

and taking the section size of the submarine cable corresponding to the minimum value in the leveling degree electric cost function value set as a target section size.

7. Offshore wind power submarine cable section type selection optimizing device based on insulation thermal fatigue life modeling, which is characterized by comprising:

The temperature sequence acquisition module is used for inputting the available annual power generation capacity time sequence and the seabed temperature time sequence of the submarine cables with different section sizes into a thermoelectric equivalent model constructed in advance to obtain the instantaneous conductor temperature sequences of the submarine cables with different section sizes;

The maximum temperature acquisition module is used for determining the maximum instantaneous conductor temperature of the submarine cable with each section size in the instantaneous conductor temperature sequence of the submarine cable with each section size;

the estimated life acquisition module is used for acquiring the estimated life of the submarine cable with different section sizes based on the insulating thermal fatigue life model;

The target section size acquisition module is used for obtaining the target section size of the submarine cable, wherein the target section size of the submarine cable enables the leveling degree electric cost function to be minimum under the constraint that the estimated service life of the submarine cable running in a given time window is not lower than a service life set value, the maximum instantaneous conductor temperature is not higher than a temperature set value and the submarine cable power is not higher than the constraint condition of the system stability limit power.

8. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the steps of the method of any of claims 1 to 6 when the computer program is executed.

9. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the steps of the method of any of claims 1 to 6.

10. A computer program product comprising a computer program, characterized in that the computer program, when being executed by a processor, implements the steps of the method of any of claims 1 to 6.