An innovative method of fault detection in power transformers

The Bayesian classifier is a priori the optimal solution for minimizing the total error in problems of statistical pattern recognition. The article suggests using the classifier as a regular tool to increase the reliability of defect recognition in power oil-filled transformers based on the results of the analysis of gases dissolved in oil. The wide application of the Bayesian method for solving tasks of technical diagnostics of electrical equipment is limited by the problem of the multidimensional distribution of random parameters (features) and the nonlinearity of classification. The application of a generalized feature of a defect in the form of a nonlinear function of the transformer state parameters is proposed. This simultaneously reduces the dimension of the initial space of the controlled parameters and significantly improves the stochastic properties of the random distribution of the generalized feature. A special algorithm has been developed to perform statistical calculations and the procedure for recognizing the current technical condition of the transformer using the generated decision rule. The presented research results illustrate the possibility of the practical application of the developed method in the conditions of real operation of power transformers.

Heat Transfer Analysis of Supercritical Methane in Microchannels with Different Geometric Configurations On High Power Electromechanical Actuator

The issue of regenerative cooling is one of the most important key technologies of flight vehicles, which is applied into both the engine and high-power electrical equipment. One pattern of regenerative cooling channels is the microchannel heat sinks, which are thought as a prospective means of improving heat removal capacities on electrical equipment of smaller sizes. In this paper, three numerical models with different geometric configurations, namely straight, zigzag, and sinusoid respectively, are built to probe into the thermal hydraulic performance while heat transfer mechanism of supercritical methane in microchannel heat sinks for the heat removal of high-power electromechanical actuator is also explored. In addition, some crucial influence factors on heat transfer such as inlet Reynolds number, operating pressure and heating power are investigated. The calculation results imply the positive effect of wavy configurations on heat transfer and confirm the important effect of buoyancy force of supercritical methane in channels. The heat sinks with wavy channel show obvious advantages on comprehensive thermal performance including overall thermal performance parameter ? and thermal resistance R compared with that of the straight one. The highest Nu and average heat transfer coefficient am appear in the heat sink with zigzag channels, but the pumping power of the heat sink with sinusoidal channels is lower due to the smaller flow loss.

Power Quality Disturbance Recognition Using Empirical Wavelet Transform and Feature Selection

With the growth of nonlinear electrical equipment, power quality disturbances (PQDs) often appear in electrical systems. To solve this, a practical heuristic methodology for PQD detection and classification based on empirical wavelet transform has been proposed. By using a multiresolution analysis tool, empirical wavelet transform, the voltage waveform signal is decomposed into several sub-signals, and some potential features are extracted in the statistical method. To reduce the feature vector dimensions, the ReliefF algorithm is used for feature selection and optimized for dimensionality reduction, which reduces the complexity of system calculation while ensuring accuracy. Finally, a classifier based on support vector machines (SVM) was built, and with the ranked feature vectors’ input, the PQD can be recognized. The experimental results verify that the classification results achieved high accuracy, which confirms the properties and robustness of the proposed approach in noisy environments.

Seismic Finite Element Analysis of Lightning Arrester Combination by Casing and Pillar Insulator

The seismic performance of electrical equipment in substations has a great impact on the normal operation of the whole substation. The results of the modal analysis show that the fundamental frequency of the three devices is in the range of 0.9Hz∼1.1Hz. The maximum stress of the casing for the three devices is respectively 55.43MPa, 45.39MPa, 35.26MPa, when the peak acceleration 0.4g seismic action is verified. The maximum stress of insulator is respectively 47.01MPa, 62.72MPa and 30.85MPa, and the maximum relative displacement of the top for the equipment is 617.2mm.

Research on artificial intelligence safety prediction and intervention model based on ship driving habits

Based on the analysis of the causes of ship accidents, the development prospect and development direction of ship intelligent safe driving, the artificial intelligence safety prediction and intervention model is put forward. This model solves the problem of ship intelligent safety prediction by using intelligent analysis technology and network technology, and promotes the development of ship intelligence and ship safety navigation technology. Additionally, it expands the channels of obtaining information, connects the ship's mechanical and electrical equipment, collects, stores and analyzes the data reasonably, and constructs the intelligent analysis and processing platform of ship small-world data processing to implement intelligent intervention. What is impressive is that it makes ship navigation safer, more economical, more reasonable and optimized, and accelerates the development of ship artificial intelligence safe navigation.

Vehicle diagnostic technology

In the article, using the example of a mechatronic control system for the engine and transmission of vehicles (automobiles), the features of the technology of their diagnosis are shown. In an electronic transmission control system, the object of regulation is mainly an automatic transmission. Also, the laws of control (programs) of gear shifting in an automatic transmission ensure the optimal transfer of engine energy to the wheels of the vehicle (TC), taking into account the required traction and speed properties and fuel economy. At the same time, the programs for achieving optimal traction-speed properties and minimum fuel consumption differ from each other, since the simultaneous achievement of these goals is not always possible. Therefore, depending on the driving conditions and the desire of the driver, using a special switch, you can select the "economy" program to reduce fuel consumption, the "power" program - to improve traction and speed properties, or the "manual" program to switch gears by the driver. In turn, self-diagnostic capabilities include: system identification and electronic control units (ECU) (ECU); recognition, storage and reading of information about static and single malfunctions; reading current real data, including environmental conditions and specifications; modeling of system functions; programming of system parameters. The individual programs for the test block are stored in the plug-in modules, while the correction and data transfer in the system is carried out via the data interface. Note also that the diagnostic process begins with the initialization of the systems - their detection in the electrical equipment of the vehicle. Upon successful initialization, it is possible to: read the error memory; erase the error memory; view the data of the next detected system or exit to the main menu; change the readings of the selected category; correct the current time; correct the current date and perform a number of additional functions.