A New Method of Power Quality Cloud Evaluation Considering Dynamic Characteristics

Comprehensive assessment of power quality is the basis for measuring power quality. SFSM (Sequential Floating Search Method) with Bhattacharyya distance is used to select the most effective power quality evaluation indices, then use three classical classifiers to verify the validity of the selected indices. Through analyzing the data collected by the monitoring points, each evaluation indicator is evaluated and screened. The reserved evaluation indices are searched by SFSM algorithm with the Bhattacharyya distance. SVM (support vector machine), KNN (K-nearest neighbor) and RBF (radial basis function) neural network are used to test the classification accuracies of the selected evaluation indices. The experimental results show that this method can find the best combination of power quality indices, which can reasonably evaluate the comprehensive evaluation level of power quality for a monitoring point.

A problem of concern in the deregulated electricity market is to obtain a global power quality (PQ) index for the supply and load side to estimate the cost of PQ in order to include it in the contracts between customers and utility companies. Existing PQ indices are usually isolated and lack the cost impact of bad PQ. This study presents an intelligent method based on artificial neural network (ANN) and fuzzy logic to obtain a quantitative global index for PQ evaluation and pricing in competitive electricity market. Taking into account the cost of PQ phenomena with their relative weights in this index, it can be used as a PQ measure in electricity tariffs by utility companies. Although individual cost assignments used in this study are subject to approximation, once the assignments are made, the calculation is consistent and gives a useful and unique measure of quality of electricity for both supply side and customer side. The proposed algorithm has been implemented on real measured data of a distribution network. The results show the capability of this method to obtain an accurate measure for PQ evaluation and pricing.

This paper puts forward a comprehensive evaluation method of regional power grid power quality, and introduces its application with real measurement data. Firstly, the conception of regional power grid power quality evaluation is proposed. And a power quality indexes system, which contained the comprehensive power quality indexes, is designed on the basis of six national standards. Secondly, the evaluation objects are divided into two levels, then the comprehensive evaluation of regional power grid power quality is achieved with weighting the subsystems and large-scale systems by scatter degree method and improved analytic hierarchy process-G1 method. Finally, according to the data presented by power quality online surveillance system of Guangzhou power supply bureau, the suitability and validity is proved by the method of area pigmentation.

Based on the relationship between rockburst and microseismic event indicators, this study proposes that the risk of rockburst in mine working faces, roadways, and even the entire mine should be studied through the “double high” risk evaluation of microseismic events. The 43 evaluation indexes of rockburst were optimized into eight indexes by using the expert scoring method. Considering the eight indexes as the basic events and the “double high” risk of microseismic events as the top event, the “double high” accident tree of microseismic events was established. According to the qualitative analysis results of the accident tree, the microseismic activity evaluation index was determined, and the “double high” risk evaluation index system was constructed for microseismic events. The system included three first-level indicators and eight second-level indicators. The fuzzy hierarchical comprehensive evaluation model was used to evaluate the “double high” risk of microseismic events in the Yanbei Coal Mine. In this paper, a microseismic monitoring and evaluation index model is constructed to simplify the existing evaluation system, which is convenient to effectively establish the connection between microseismic monitoring data and rockburst index and provide important theoretical support for underground monitoring and rockburst prevention.

Simultaneous monitoring of two comprehensive quality evaluation indexes of frozen-thawed beef meatballs using hyperspectral imaging and multi-task convolutional neural network

Wind power forecasting evaluation indexes reflect the accuracy and reliability of prediction models, being an important basis for positioning and improving errors. The current evaluation indexes are numerous and mixed with each other, lacking a clear layer-by-layer classification, and their physical meanings are mostly on the statistical level and cannot reflect the interaction with the power grid. A comprehensive error evaluation method for wind power forecasting is established. Taking time scale as the main criterion, the evaluation method covers the mathematical and applied characteristics of errors. The former is organized from multiple dimensions such as expectation, extreme value and distribution, and diversified types such as point and probability prediction separately. The latter considers the impact of errors on power quality, day-to-day scheduling, and system planning in various stages. Finally, the data of an actual operating wind farm are taken as an example to illustrate the application and effectiveness of the evaluation method.

Touch screens have gradually replaced interactive devices such as buttons and keyboards in the cockpit with natural and intuitive characteristics. Touch interaction also may lead to more head-down time and unintended touch. However, on the battlefield, the lives of pilots are affected by the efficiency of touch interaction. The purpose of this study is to establish and verify metrics to evaluate the usability of the cockpit touch screen. These metrics cover the pilots ' cognitive decision-making, operational performance, physiological performance, control and display resources of the fighter touch screen, etc. In this study, the ergonomic evaluation index of cockpit touch screen was established and verified by specific methods, which mainly constructed from the pilots, fighters, flight environment and other perspectives. Based on the traditional ergonomics evaluation theory and its application, and combined with the national standards and industry standards of aircraft touch screen, this study describes the new ergonomics evaluation metrics suitable for aircraft cockpit touch screen. According to the methods of construction and classification of metrics system of multiple research objects and fields, three levels evaluation metrics model was proposed by our research groups. The first-level metrics of the framework mainly include the cognitive layer, the interaction layer and the impression layer. With regards to the perception layer, it mainly focuses on the process of the pilot receiving information to complete the action, which includes perception/ cognition, memorization/ learning and action/response. Furthermore, the interaction layer mainly includes display attributes, control attributes and display-control comprehensive attributes, while the impression layer focuses on the subjective experience of the pilot after the operation. In addition, the evaluation index model of this study includes 3 first-level metrics, 6 second-level metrics, and 48 third-level metrics. In this study, 12 experts who specialized in the area of aviation efficiency evaluation were investigated to verify the effectiveness and reliability of the metrics framework from the aspects of the necessity, feasibility, identification of a single metric, and the integrity and redundancy overlap of the overall metrics system. The experimental results show that for every single index, they own high identification and feasibility, and no serious overlap between each index can be found. In terms of necessity, we combined with necessity coefficient data and expert interview after the experiment, and six third-level metrics with the coefficient of necessity lower than the general level were excluded. With respect to the metric framework, high integrity, low structural redundancy of the evaluation index system, and high independence between the evaluation structures can be found. Moreover, the overall evaluation index model has high reliability and validity. Overall, we study and establish an evaluation index system of the cockpit touch screen. It helps to find the problem of design parameters during the cockpit touch screen design，and improve the operational performance and survival probability of pilots.

The mobile welding robot based on a hybrid power drive system is a system with complex control characteristics such as nonlinearity, strong coupling, and disturbance of working environment. These characteristics have different effects on the control performance. In order to improve control characteristics of the mobile welding robot, it is necessary to study an effective evaluation method to explore the influence of these parameters on the control performance of the mobile welding robot. In the process of seam tracking, the operation indexes of welding robot system are determined by comprehensive evaluation. On the premise of ensuring tracking accuracy and stability, the energy distribution of hybrid power system is optimized to improve results of continuous power supply time. Therefore, a comprehensive evaluation of the welding robot is established, which is combined information entropy and Kernel Principal Component Analysis (KPCA). The evaluation parameters are divided into the first-level evaluation index and the second-level evaluation index. The evaluation model is established by using information entropy, and the data are linearized and dimensionally reduced by using the KPCA. The results show that the method can well deal with and analyze the nonlinear relationship between various indexes. At the same time, the numerical relationship between performance indexes can be established. On this basis, a comprehensive performance evaluation theory based on information entropy, and nuclear principal components is established. Finally, the comprehensive evaluation results are brought into the energy management optimization strategy. The experimental results show that this method not only improves the accuracy of weld tracking, but also ensures the stability of the robot and reduces energy consumption.

Evaluation of power quality governance effect is of great reference significance for the optimization of the governance scheme. Considering the physical characteristics of power quality and governance benefits comprehensively, an evaluation index system of power quality governance effect including three-dimensional indexes of power quality, economic benefits, and service evaluation is established. Secondly, based on the fuzzy comprehensive evaluation method, a governance effect evaluation model of power quality is established. The comprehensive weighting method combined with analytic hierarchy process and entropy weight coefficient method is adopted to determine the index weight. The membership function is constructed by the assignment method revised by experts and customers. Finally, a case study of a city distribution network is used to verify the effectiveness of the proposed governance effect evaluation index system and evaluation model.

Comprehensive evaluation of college students' network literacy is one of the important contents of students' assessment. Because the existing methods simply superposition the evaluation index results, the evaluation results of different students are too different and not scientific. The comprehensive evaluation system of college students' network literacy is put forward and designed. By using Web technology, the system framework is designed with college students' network literacy module as the core, and the comprehensive evaluation subsystem of college students' network literacy is analyzed in detail. Firstly, the evaluation index system is established, which is divided into four primary indexes: network cognitive literacy, network knowledge literacy, network security literacy and network civilization literacy. Based on the evaluation index, the weight of different evaluation indexes is calculated by analytic hierarchy process, the comprehensive evaluation of network literacy is carried out based on fuzzy evaluation method, and the correlation coefficient is introduced in the calculation process. Avoid the students too different evaluation unscientific problems, achieve system design. The experimental results show that the system has better accuracy and is more scientific than the traditional literature for the comprehensive evaluation of college students' network literacy.

The Wuqi area of the Ordos Basin boasts significant resource potential in the Chang 8 member of the Yanchang Formation. However, under the dual control of lithology and physical properties, reservoirs are generally dense and heterogeneous, and the quality of the oil layer changes rapidly, which brings difficulties to the optimization of favorable areas. To evaluate the reservoir quality more accurately, based on core observations, and logging and dynamic data analysis, combined with casting thin sections, scanning electron microscopy, high‐pressure mercury injection, nuclear magnetic resonance, and other related experiments, different reservoir types and characteristics were analyzed, and a comprehensive method for evaluating the reservoir quality was established. There are three types of sand body structures in the shallow‐water delta of Chang 8 in the study area, including the continuous superposition type, interval superposition type, and lateral single‐layer type. They mainly experienced diagenesis, such as compaction, cementation, and dissolution. Among these, porosity loss in the Chang 8 reservoir due to compaction and cementation reached 79.3%, consistent with trends observed in other continental tight oil plays such as the Songliao and Junggar Basins, while the improvement in physical properties due to dissolution was minimal. The main parameters influencing different reservoir types are optimized, and the comprehensive classification with the multivariate coefficient is constructed after providing coefficients with different weights. Four reservoir types are quantitatively delineated, among which the physical properties of Type I reservoirs are the best and the physical properties of Type IV reservoirs are the worst. Combined with the difference in the characteristics of sensitive logging curve responses, four logging parameters, density, neutron, resistivity, and acoustic time difference, are optimized, and different reservoir types are quantitatively identified by Fisher discriminant analysis. Comprehensively considering the change in the vertical sand body structure and reservoir type, the three key parameters of interlayer density, interlayer frequency, and reservoir thickness are selected, and the comprehensive evaluation index N of reservoir quality is innovatively constructed. The proposed evaluation index effectively decouples lithological and petrophysical variations, refining reservoir quality assessments for enhanced exploration and production strategies. The greater the N value is, the better the quality of the oil layer. The smaller the N value is, the thinner the oil layer, the more developed the interlayer, and the worse the oil layer quality. The N index exhibits a strong correlation with production characteristics, indicating that the method has effectively evaluated reservoir quality and provided a theoretical basis for targeting favorable areas.

Study on the Evaluation Framework System for Regional Comprehensive Transport Planning

Aiming at the nonlinear relationship between the evaluation indexes and the complex grade of power quality, a power quality evaluation method is proposed based on model of pulse coupled neural network (PCNN). The operating schematic is analyzed according to PCNN modeling. The input power quality grade is controlled by threshold value, and the evaluation grade is output by neuron ignition. The evaluation methods between PCNN and fuzzy neural network are compared through the measured data, the results indicate that PCNN method is more scientific and accurate, and provides a new method to solve the problem on power quality evaluation of distribution network containing microgrid.

Machine vision system for food grain quality evaluation: A review

Abstract- Based on Fast Fourier Transform (FFT), power quality indices (PQIs) definitions contained in the standards cannot be successfully applied for non-stationary signals analysis in unbalanced three-phase systems with non-sinusoidal conditions. Unlike FFT, Discrete Wavelet Transform (DWT) gives more accurate definitions preserving time-frequency information and reduces the computational effort. This paper proposes a comparative analysis of definitions employing these two instruments for unbalanced three-phase systems case in sinusoidal and nonsinusoidal situations using waveforms captured with data acquisition system which contains Hall voltage and current transducers. The experimental testing of harmonic distortion was made for a RL unbalanced three-phase load, a three-phase rectifier with diodes (TPRD) and a rectifier with near sinusoidal currents (RNSIC). I. I NTRODUCTION For the electric power quality monitoring, the IEEE working group has analysed the customers expectations concerning electric power delivery, the susceptibility limits of the electric and electronic equipments connected at the electric network and thus obtained the standards regarding the evaluation methods of electric power quality, the parameters that define this concept and the functioning classes of the measurement tools [1-3]. In the last years electric power quality became un important issue in the power systems domain because of the increased usage of nonlinear loads which are producing great harmonic distortion in power supply [4-12, 33-36]. Voltage and current quality can be determined based on the deviations between the real voltage/current and the ideal voltage/current waveforms [13]. These deviations are counted power quality disturbances and can be classified as stationary (with time unchangeable characteristics) or non-stationary (with time changeable characteristics) and each of them as sinusoidal or non-sinusoidal. The Fast Fourier Transform (FFT) approach in Power Quality Indices (PQIs) definition is replaced in this study with a time-frequency domain approach using Discrete Wavelet Transform (DWT). This method eliminates the FFT drawbacks as high computational effort, time related information loss, spectral leakage and provides representations for any non-stationary waveforms [14-17]. DWT is a useful tool in the waveforms analysis due to its accuracy and sensitivity at signal irregularities [5], [32]. The waveforms of voltage and current are obtained using a data acquisition system with linear/nonlinear loads composed of a Digital Signal Processor (DSP) board with high-speed 12 bit Analog to Digital Converters (ADC) coupled to a three-phase system using the Hall transducers. This paper presents a comparative analysis of DWT based measurements of power quality indices and the IEEE Standard 1459-2000 based values using unbalanced linear three-phase systems and nonlinear power loads. The power quality disturbances are calculated with a RL unbalanced three-phase load, a three-phase rectifier with diodes (TPRD) and a rectifier with near sinusoidal currents (RNSIC). II. T