Evaluation Method Of Power Quality Research Articles

Comprehensive Evaluation of Power Quality Based on AHM-CRITIC Method

In order to manage the level of power quality more effectively, a comprehensive evaluation method of power quality based on Attribute Hierarchy Model (AHM)- Criteria Importance Through Intercriteria Correlation (CRITIC) is proposed in this paper. Firstly, collect expert opinions and determine the subjective weight of each power quality index based on AHM method. Secondly, the power quality data of monitoring points are counted and processed based on CRITIC method, so as to obtain the objective weight of each index. Then, the comprehensive weight of each power quality index is determined based on the minimum discrimination information method. Finally, according to the standard grading and index comprehensive weight, the comprehensive power quality evaluation of each monitoring point is carried out. Through the analysis of practical examples, it is verified that the proposed method can comprehensively consider the subjective and objective factors and obtain more accurate and comprehensive power quality evaluation results.

Comprehensive evaluation of power quality of coal mine power grid based on equilibrium empowerment and improved grey relational projection method

Aiming at the problem that the current comprehensive evaluation system of power quality is not fully applicable to coal mine power grid, and the load characteristics of coal mine electrical equipment are less considered, a comprehensive evaluation method of power quality of coal mine power grid based on equilibrium empowerment and improved grey relational projection is proposed. According to the actual situation and load characteristics of coal mine power grid, the power quality index system of coal mine power grid is established, and the grade is divided according to the national standard. The G-1 method is used to determine the subjective weight of the index, the improved CRITIC method is used to determine the objective weight of the index, and the subjective and objective weights are combined with the equilibrium idea of game theory to determine the equilibrium weight, so as to overcome the limitation of single weight. The TOPSIS method is combined with the GRA method, and the positive and negative ideal sequence is introduced to make up for the deficiency of the traditional GRA method. The vector projection method is used to construct the grey relational projection model, and the projection value is used to comprehensively evaluate the power quality of coal mine power grid. The example analysis shows that the proposed method is effective and feasible, can correctly evaluate the power quality of each test point, and can reasonably divide the power quality grade of each test point, which provides a basis for power quality management.

A comprehensive evaluation method of electric power quality based on improved grey correlation analysis

Comprehensive evaluation of electric power quality is essential to the implementation of effective power quality control. In traditional evaluation methods, the weight of indicators is fixed and lacks flexibility. Aiming at this problem, this paper has proposed a power quality evaluation method based on improved grey correlation method. This method uses improved analytic hierarchy process (IAHP) to calculate subjective weights and introduces the improved entropy weight method (IEWM) that is modified using variable weight theory which calculates variable objective weights. The proposed method also uses intergrated weighting to combine the subjective and objective weights calculated above, obtaining multidimensional indicator weights. Finally, improved gray correlation analysis (IGCA), improved through employing ideal solution theory and logarithmic information aggregation method based on barrel theory, is implemented in this method to comprehensively evaluate electric power quality.

Comprehensive power quality evaluation method of microgrid with dynamic weighting based on CRITIC

The power quality assessment provides a reference for power quality management and control of microgrid operation. In terms of reflecting the correlation of power quality indexes and the dynamic changes of microgrid operating conditions, the traditional power quality assessment methods need to be improved. A power quality comprehensive evaluation based on CRITIC and dynamic coefficient is proposed in this paper. In this method, the objective weight of power quality indicators in single node is determined by using the intensity of conflict and contrast firstly. For the node weight calculation, the dynamic coefficient is proposed to reflect the different influence degree of node with different connected load. The proposed method in this paper can reflect both the internal characteristic of data sequence and the relationship between different data sequences. In addition, it also can reflect the dynamic changes of microgrid. Finally, an example is used to verify the feasibility of the proposed method.

Research on Power Quality Evaluation Method for High Energy-consuming Enterprises

With the increase of the voltage level of the power system, the demand for electric energy of high energy-consuming enterprises continues to increase, which puts forward higher requirements on the power quality. As power quality problems become more and more prominent, how to manage power quality scientifically and reasonably has attracted more and more attention from power quality workers. At the same time, users have increased their power quality requirements and the continuous development of power marketization. To achieve comprehensive power quality management, it is necessary to have a scientific, accurate, and standardized assessment of power quality. In-depth understanding and understanding of power quality, attach great importance to the harm and impact of power quality degradation on the operation of the power supply system, and it is particularly urgent to achieve comprehensive power quality management.

A power quality evaluation method for distribution system with renewable energy

ABSTRACTPower quality evaluation data are heterogeneous and fluctuating, and there are large subjective factors in the evaluation process. To solve this problem, a power quality evaluation method based on incentive punishment factor and the ordered weighted aggregation (OWA) operators was proposed. The integrity and fairness of the evaluation information were guaranteed, through the homogenisation of the evaluation data. And using incentive and penalty factors to calculate the single index evaluation value without considering the time factor. By introducing the time weights and adopting the linear target programming model and ordered the weighted averaging operator to get the primary evaluation values of the indices in the inspection period. Then, the minimum variance method was used to get index weights, and the ordered weighted geometric averaging (OWGA) operator was applied to obtain the comprehensive evaluation value of the power quality. Finally, the power quality of a distribution system with photovoltaic generation under different load conditions is analysed as an example. The results showed that the method proposed in this paper distinguishes the power quality level under various load conditions significantly, which verify the feasibility and effectiveness of the model.

Several Typical Indexes Assessment for City Area Substation Power Quality

With the development of frequency converter, lots of electrical equipments are using the technology to save energy, but by using this technology, the harmonic voltage and harmonic current is increasing much more quickly than before. In this article, a deep research about the characteristics in power supply of city area substation is implemented. At last, a new power quality evaluation method for city area substation is put forward, which is based on the typical power quality parameters in city. This method is established by four elements, which are: harmonic voltage, harmonic current, voltage change and power. All these elements constitute a new method to evaluate the power quality of city area substation.

Power quality assessment based on combinatorial weight method of variance maximizing

In order to improve the limitation of the existing wind power grid connection quality assessment methods, a more reasonable combinatorial weight method considering the advantages of both subjective and objective is proposed. The objective function is to maximize the variance of the evaluation object under the combined weight, and to optimize the optimal solution of the model as the index weight. On this basis, an adaptive fuzzy neural network is used to evaluate the power quality evaluation method based on the combination weight of the maximization of variance. This method is used to evaluate the 220KV bus power quality of the Weifang power grid. The results not only verify the reasonableness of the proposed variance maximization combination weight weighting, but also verify the effectiveness of the proposed adaptive fuzzy neural network power quality comprehensive evaluation method, which provides a new method for the study of the evaluation method.

Multi Element Method Evaluation for Urban Region Power Quality Assessment Based on Harmonic Monitoring Platform

Nowadays, more and more people focused on the power supply using experience, which means people paid much more attention to the power quality of urban grid. With the development of the area of city, there are many factories are involved in the urban region, which causes much more power quality problems than before. In this article, we analyzed several evaluation methods of power quality used for now, then we make a deep research about the characteristics in power supply of urban region. And with the construction work of harmonic monitoring platform of State Grid, we need to make a quick judgment for some special supply point, such as government, hospital, bank and so on. At last, we put forward a new power quality evaluation method for urban region, which is based on the unique power quality parameters of power supply in city. This method is established by four elements, which are: harmonic voltage, harmonic current, voltage change and power, all these elements constitute a new method to evaluate the power quality of urban region in a short time.

Study of the Power Quality Comprehensive Evaluation Method

The scientific evaluation of power quality is the basic condition for the treatment of electric energy pollution. In this paper, the relevant concepts and various indexes of power quality are analyzed based on the internal and external power quality standards. The evaluation method of power quality is divided into the specific analysis of single index evaluation and comprehensive evaluation. This paper proposes four evaluation methods of single index, including based on fuzzy mathematical single index evaluation method, based on fuzzy mathematics in various energy index commonly used membership function method, based on probability and statistics of the single index evaluation method and based on the main use of power grid planning, power grid construction and interference load before access to the simulation of the individual indicators to predict the assessment method. The weight selection method used in the comprehensive evaluation of power quality is analyzed from the subjective weight to the objective weight.

An evaluation method of power quality about electrified railways connected to power grid based on PSCAD/EMTDC

The existing modeling process of power quality about electrified railways connected to power grid is complicated and the simulation scene is incomplete, so this paper puts forward a novel evaluation method of power quality based on PSCAD/ETMDC. Firstly, a model of power quality about electrified railways connected to power grid is established, which is based on testing report or measured data. The equivalent model of electrified locomotive contains power characteristic and harmonic characteristic, which are substituted by load and harmonic source. Secondly, in order to make evaluation more complete, an analysis scheme has been put forward. The scheme uses a combination of three–dimensions of electrified locomotive, which contains types, working conditions and quantity. At last, Shenmao Railway is taken as example to evaluate the power quality at different scenes, and the result shows electrified railways connected to power grid have significant effect on power quality.

Fuzzy Comprehensive Evaluation Method of Power Quality Based on Modified Entropy Weights

To improve the limitations of information entropy in the power quality evaluation process, a fuzzy comprehensive evaluation method was proposed on Modified Entropy Weights and Catastrophe Verification. Through summing up the six indexes of power quality, and establishing the evaluation level boundary, the positive and negative entropy weights were reckoned for the power quality monitoring units; The fuzzy features and evaluation was improved to be depicted for power quality with Exponent method, and the five level membership function was set for the power quality evaluation; Then, the mechanism was set up for the fuzzy comprehensive evaluation operation. Finally, with the modified entropy information combination mode and the fuzzy catastrophe mode, the fuzzy comprehensive evaluation and comparative analysis was carried on for such power quality. Case showed, the power quality evaluation conclusion of Information catastrophe mode has the good consistency with the weight combination mode of the positive and negative entropy, which could realize the distinction and system evaluation to the different monitoring units.

6-2 Quantitative Evaluation Method of Power Quality Based on Fuzzy Theory

In modern power market environment, users’ requirements for power quality are increasing day by day. For the characteristic of power quality is difficult to quantify assessment, this paper describes the basic theory and method by using fuzzy theory to power quality indexes of quantitative evaluation. Examples of analysis have verified the practicality and validity of the method.

The Power Quality Evaluation Method Based on the Matter-Element Comprehensive Evaluation Method

As for the pricing by electrical energy quality and the decision of rewards and penalties based on the examination at assessment point, Comprehensive evaluation on power quality is one of the principal foundations. To analysis and evaluate electric power quality for electric power company is a focus research at present. In this paper, the power quality evaluation model based on the matter-element extension theory is applied to power quality evaluation service. For power quality evaluation system of the characteristics of the complexity and incompatibility between various indicators hierarchies, this paper applied the theory of matter-element extension constructing Matter-element model, and identified level of power quality of power supply company through the calculation of weight and the correlation service. Taking GanSu Grid Company as an example to evaluate power supply quality, the results show that the evaluation results of power quality evaluation method based on the matter-element evaluation method are more objective, more precise and more reasonable.

Incentive and Punishment Mechanism Based Method Study of Power Quality Dynamic Comprehensive Evaluation

A dynamic comprehensive evaluation method of power quality based on incentive and punishment mechanism is proposed. At the beginning, the index system is designed and unified. Next, the incentive and punishment mechanism model of each index is established. Then, the vertical and horizontal scatter degree method and minimal variability theory are applied to calculate the comprehensive evaluation value of all the indices on every time period and on the whole time series respectively. Finally, the realistic example demonstrates that this method can easily differentiate the quality of different evaluation objects.

Comprehensive Evaluation of Power Quality Based on the Integration of Rough Set and Evidence Theory

In order to assess the power quality objectively and effectively, a comprehensive evaluation method of power quality based on rough set and D-S evidence theory has been proposed in this paper. The method combines rough set theory by means of defining the decision-making strength and expansion rules and using the decision-making table to obtain the basic probability assignment of D-S evidence theory, then by applying the fusion rules of evidence theory to integrate the various indicators of power quality, the pros and cons of ordering from each power quality evaluations can be obtained to achieve a comprehensive evaluation of power quality. The examples show that the results of power quality evaluation are more objective and rational by using this method. So it can prove the correctness and superiority of this method.