CN-121999914-A - Method for realizing synergistic improvement of oxidation resistance and low-temperature fluidity of oil by mixing various esters

CN121999914ACN 121999914 ACN121999914 ACN 121999914ACN-121999914-A

Abstract

The invention belongs to the field of application of insulating materials of transformers, and particularly relates to a method for realizing synergistic improvement of oxidation resistance and low-temperature fluidity of oil by mixing various esters. According to the relation between oxidation resistance and low-temperature fluidity, adopting a genetic algorithm to determine the optimized components of the natural ester fatty acid, then obtaining different natural ester proportioning schemes through matrix calculation, and carrying out miscibility on the selected base oil sample according to the proportioning schemes to prepare the high-performance natural ester insulating oil. The method realizes the cooperative promotion of oxidation resistance and low-temperature fluidity, the insulating oil has excellent electrical reliability, and the method has the characteristics of rapid operation, obvious effect and wide application, and provides theoretical guidance for the promotion of good insulating effect of the transformer.

Inventors

ZHAO SHUAI
FENG DAWEI
YAN XIAOYU
LI XUELU
ZHANG KAIYAN
LI ZIYI
WANG LU

Assignees

河北工业大学

Dates

Publication Date: 20260508
Application Date: 20241104

Claims (12)

1. The method for realizing the synergistic improvement of the oxidation resistance and the low-temperature fluidity of the oil by mixing a plurality of esters is characterized by comprising the following steps: Constructing a performance optimization model; Solving the optimized components of the natural ester fatty acid by using a genetic algorithm to a performance optimization model; According to the optimized components of the natural ester fatty acid, calculating to obtain a natural ester proportioning scheme by a matrix solving method; According to the natural ester proportioning scheme, the selected base oil sample is mixed and dissolved to prepare the high-performance natural ester insulating oil.
2. The method for achieving synergistic improvement of oxidation resistance and low-temperature fluidity of oil by mixing various esters according to claim 1, wherein the performance optimization model takes natural ester fatty acid components as independent variables, pour points as constraint conditions and induction period as an optimization target.
3. The method for achieving synergistic enhancement of oil oxidation resistance and low temperature fluidity by mixing multiple esters according to claim 1, wherein the performance optimization model is solved by using a genetic algorithm, comprising the steps of: Coding, namely converting components of different natural esters into different chromosomes, wherein the mass fraction of each natural ester component corresponds to a gene sequence on the chromosome; Fitness selection, using fitness functions to evaluate the performance of optimized components of different natural ester fatty acids; Selecting, namely sequencing the optimized components of the natural ester fatty acid according to the fitness function value by adopting a selection operator; Crossing, performing crossing operation on optimized components of the natural ester fatty acid to generate a new chromosome combination; variation, introducing random variation on the chromosome, simulating small variation of component mass fraction ratio; and judging the condition, after each iteration, evaluating the adaptability of the optimized components of different natural ester fatty acids, if the optimized components of the natural ester fatty acids meet the preset performance index, decoding the optimized components as an optimal solution, and if the optimized components of the natural ester fatty acids do not meet the preset performance index, continuing the iteration until the maximum iteration times are reached or the optimized components of the natural ester fatty acids meeting the condition are found.
4. The method for achieving synergistic enhancement of oil oxidation resistance and low temperature fluidity by mixing multiple esters according to claim 1, wherein the natural ester fatty acid component comprises C 18:0 :stearic acid, C 18：1 :monounsaturated fatty acid, C 18：2 :linoleic acid, C 18：3 :linolenic acid.
5. The method for achieving synergistic enhancement of oil oxidation resistance and low temperature fluidity by mixing multiple esters according to claim 1, wherein the method is calculated by a matrix solving method and comprises the steps of: constructing an equation set for solving a target component according to the components of different natural esters; and constructing a coefficient matrix based on the equation set, and solving through matrix elimination and back substitution to obtain the weight proportion of each set.
6. The method for achieving synergistic improvement of oxidation resistance and low-temperature fluidity of oil by mixing various esters according to claim 1, wherein a high-performance natural ester insulating oil is prepared, comprising the steps of: Accurately weighing the natural ester of the required type according to a preset formula, and mixing the natural ester in a beaker according to a proportion; stirring at 700r/min for 60min at room temperature to ensure that the natural esters are fully and uniformly mixed; The sample was dried under 90℃/50Pa vacuum for 48h to remove moisture and gases from the natural ester.
7. The method for achieving synergistic enhancement of oil oxidation resistance and low-temperature fluidity by mixing multiple esters according to claim 1, wherein the oil analysis for preparing high-performance natural ester insulation oil comprises oxidation resistance and low-temperature fluidity synergistic enhancement effect analysis and physicochemical electrical parameter analysis.
8. The method for achieving synergistic enhancement of oil oxidation resistance and low temperature fluidity by mixing multiple esters according to claim 2, wherein the constraints are: Wherein PP is pour point, C 18：0 is mass fraction of stearic acid, C 18：1 is mass fraction of monounsaturated fatty acid, C 18：2 is mass fraction of linoleic acid, C 18:3 is mass fraction of linolenic acid, and the objective function is: max{IP=-1.52*(C 18：1 +41*C 18：2 +98*C 18：3 )/100+114.65} Wherein IP is the oxidation induction period of natural ester, C 18：1 is the mass fraction of monounsaturated fatty acid, C 18：2 is the mass fraction of linoleic acid, and C 18:3 is the mass fraction of linolenic acid.
9. A method for achieving synergistic enhancement of oil oxidation resistance and low temperature fluidity by mixing multiple esters according to claim 3, wherein the fitness function used is: Wherein IP is the induction period, PP is the pour point, T ref is the reference temperature, w 1 and w 2 are the weight coefficients, and the adopted selection operators are: Wherein P i is the probability that the optimized component i of the natural ester fatty acid is selected, and f i is the fitness of the optimized component i of the natural ester fatty acid.
10. The method for achieving synergistic enhancement of oil oxidation resistance and low temperature fluidity by mixing multiple esters according to claim 5, wherein the construction of the equation set for solving the objective component is: The constructed coefficient matrix is as follows: Wherein a i 、B i 、C i (i=0, 1,2, 3) is the mass fraction of C 18：0 、C 18：1 、C 18：2 、C 18：3 in the natural ester component, l, m, n are the corresponding percentages of the natural esters, and b i is the optimal component ratio.
11. The method for achieving synergistic enhancement of oxidation resistance and low-temperature fluidity of oil by mixing a plurality of esters according to claim 7, wherein the analysis of synergistic enhancement effect of oxidation resistance and low-temperature fluidity and the analysis of physicochemical electrical parameters comprises the steps of: testing the IP value of the prepared natural ester insulating oil by adopting a Rannimat method, and comparing the test result with the IP value of soybean oil; The pour point of the prepared natural ester insulating oil is tested according to the national standard GB/T3535-2006 pour point determination method of petroleum products, and the test result is compared with the pour point of soybean oil. Obtaining the power frequency breakdown voltage value of the insulating oil through experiments, and comparing the test result with the power frequency breakdown voltage value of the soybean oil; The kinematic viscosity of the prepared natural ester insulating oil is tested according to GB/T265-88 petroleum product kinematic viscosity calculation method and kinematic viscosity measurement method, and the test result is compared with the kinematic viscosity of soybean oil.
12. The method for achieving synergistic improvement of oxidation resistance and low-temperature fluidity of oil by mixing various esters according to claim 11, wherein the experimental obtaining of the value of the power frequency breakdown voltage of the insulating oil comprises the steps of: placing the prepared natural ester insulating oil in a vacuum drying oven, and drying for 24 hours under the environment of 50Pa and 100 ℃; After the natural ester insulating oil is sufficiently dried, using an insulating oil dielectric strength automatic tester to perform boosting test on the oil product at a boosting rate of 2kV/s until breakdown occurs in the oil product; each set of prepared natural ester insulating oils was independently measured 12 times.

Description

Method for realizing synergistic improvement of oxidation resistance and low-temperature fluidity of oil by mixing various esters Technical Field The application belongs to the field of safe and stable operation of power equipment, and relates to a method for realizing synergistic improvement of oxidation resistance and low-temperature fluidity of oil by mixing various esters. Background With the continued growth of global power demand and the widespread use of clean energy, the transformer market has shown a steadily increasing trend, and the 2029 global power transmission transformer market size is expected to increase to 846.41 billions of yuan. In this trend, oil-immersed transformers are widely used in power systems by virtue of their energy saving and low noise. However, mineral insulating oils used in conventional oil-immersed transformers are increasingly prominent due to environmental and safety concerns, and their use has been severely limited, particularly in the european union countries. The natural ester insulating oil has good biodegradability, regenerability and environmental protection, has an ignition point of more than 300 ℃ and good electrical property, and becomes an ideal substitute for traditional mineral oil. There has been a great deal of attention in recent years. The characteristics of high ignition point and good biodegradability make the oil become an ideal substitute for traditional mineral oil. At present, various types of natural ester insulating oil have been exemplified on a global scale, and the cumulative installation amount of the natural ester oil-based transformer on the global scale has been over 200 ten thousand up to now. Wherein, the And BIOTEMP is a typical representation of natural ester insulating oils, with a maximum application voltage rating of up to 420kV. Although natural ester insulating oil transformers are widely used, poor oxidation resistance is a major disadvantage of existing natural ester insulating oils. Poor oxidation resistance can lead to oxidative degradation of natural esters during long-term operation, reducing dielectric strength and dielectric properties, thereby affecting the reliability of the transformer. Particularly in special scenes of high operation and maintenance difficulty, high cost and the like of offshore wind power, the oxidation resistance of the insulating oil is required to be higher. Therefore, improving the oxidation resistance of natural ester insulating oil is a problem to be solved. Meanwhile, in order to facilitate popularization and application of the natural ester insulating oil in cold climate areas, the natural ester needs to have good low-temperature fluidity, so that the synergistic improvement of oxidation resistance and low-temperature fluidity is a key technical bottleneck for improving the comprehensive performance of the natural ester insulating oil. Disclosure of Invention In view of the above-mentioned drawbacks or shortcomings of the prior art, the present application is directed to a method for achieving synergistic enhancement of oxidation resistance and low temperature fluidity of oil by mixing various esters, in order to solve the problems existing in the prior art. According to the relation between oxidation resistance and low-temperature fluidity, adopting a genetic algorithm to determine the optimized components of the natural ester fatty acid, then obtaining different natural ester proportioning schemes through matrix calculation, and carrying out miscibility on the selected base oil sample according to the proportioning schemes to prepare the high-performance natural ester insulating oil. The method realizes the cooperative promotion of oxidation resistance and low-temperature fluidity, the insulating oil has excellent electrical reliability, and the method has the characteristics of rapid operation, obvious effect and wide application, and provides theoretical guidance for the promotion of good insulating effect of the transformer. The application provides a method for realizing the synergistic improvement of oxidation resistance and low-temperature fluidity of oil by mixing a plurality of esters, which comprises the following steps: Constructing a performance optimization model; Solving the optimized components of the natural ester fatty acid by using a genetic algorithm to a performance optimization model; According to the optimized components of the natural ester fatty acid, calculating to obtain a natural ester proportioning scheme by a matrix solving method; According to the natural ester proportioning scheme, the selected base oil sample is mixed and dissolved to prepare high-performance natural ester insulating oil; furthermore, the performance optimization model takes the natural ester fatty acid component as an independent variable, pour point as a constraint condition and induction period as an optimization target. Further, the method for solving the performance optimization model by u