Search

This study has designed a set of motor operating devices for a 126 kV vacuum circuit breaker (VCB) to improve its reliability and controllability. A finite‐angle permanent magnet brushless motor (FAPMBM) with a multi‐slot stator structure and a dovetail rotor structure has been designed based on the torque and speed requirements of the motor. These requirements were determined by a dynamic analysis of the operating device and its short‐time, finite‐angle working characteristics. The work performance of the prototype motor has been evaluated in an online experiment with a 126 kV VCB, and based on this, a segmented control method has been designed. The motion process of the operating device has been divided into four stages in combination with the output torque demand of the driving motor. At each stage, the output torque of the motor has been changed dynamically to prevent contact collision, shorten the pre‐breakdown time, and make the circuit breaker work more reliably. The results show that the FAPMBM can meet the operating time and speed requirements of the interrupter for the operating device. In addition, the segmented control method improves the work reliability and optimizes the movement of the operating device, which helps the circuit breaker work intelligently. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The high‐temperature electric‐actuated valve widely adopts the split structure, and the valve stem drives the opening and closing of the valve after passing through the high‐temperature packing and sealing structure. However, the transmission chain is too long, which cannot meet the pursuit of small volume and lightweight in the nuclear industry. In this paper, a novel integrated structure of high‐temperature direct drive electric‐actuated valve canned permanent magnet synchronous motor (DDEAV‐CPMSM) is proposed. The structure omits the dynamic sealing structure composed of stuffing box, pressure plate and pressure sleeve, as well as the transmission structure of gears and couplings, and the reliability is significantly improved. This paper focuses on the calculation of the dimension parameters, thermal load design, and electromagnetic vibration of DDEAV‐CPMSM, and compares it with the integrated structure of the induction motor to explore the optimal topology of the high‐temperature electric‐actuated valve. Aiming at the problem of serious heat generation in limited space, it is difficult to simulate the running time of high‐temperature valve. Based on the magneto‐thermal coupling method, a 3D temperature field model considering high‐temperature heat source, canned sleeve eddy current loss, and hydraulic friction loss is established. The steady‐state temperature distribution of the system at high temperature and the transient temperature change law of valve opening and closing are analyzed, and the minimum time of secondary start‐up and the maximum running time under fault conditions are further studied, to provide a theoretical basis for the application of DDEAV‐CPMSM. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The high‐temperature canned electric‐actuated valve permanent magnet synchronous motor (CEAV‐PMSM) directly drives the valve load, which is prone to eccentricity operation, causing greater system vibration and shortening the valve operating life. In order to analyze the electromagnetic and structural characteristics of CEAV‐PMSM under different eccentricity faults, this paper uses analytical methods to derive the magnetic field distribution of the motor under normal and eccentricity conditions. Then, the Maxwell Stress Tensor method is used to derive the expression of the radial electromagnetic force under normal and eccentricity conditions, and the order of space–time harmonics that have a greater impact on CEAV‐PMSM are summarized. After that, the electromagnetic performance comparison of the three pole‐slot combinations under different eccentricity conditions, and the harmonic orders during eccentricity is analyzed by Fourier transform to obtain the optimal pole‐slot combination, which verified the correctness of the analytical calculations. In addition, the influence of different eccentricity conditions on the radial force density and unbalanced magnetic pull are studied. On this basis, the vibration response of the motor under eccentricity is analyzed, and the influence of the canned sleeve on the vibration performance of the motor is discussed. Finally, the modal analysis of CEAV‐PMSM is carried out to prevent the occurrence of resonance under eccentricity, which provides some references for reducing the vibration and noise of the canned electric‐actuated valve. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper proposes an analytical no‐load magnetic field model taking account of the curvature coefficient to compute the no‐load magnetic field of parallel direct‐driven conjoined permanent magnet synchronous motor (PDC‐PMSM). The shortcomings of the 3‐D finite element method are avoided, such as the time‐consuming and sensitive to finite element meshes. As well as, putting forward the design method of the motor. A 2‐D subdomain model of PDC‐PMSM can be obtained by segment 3‐D model at the average radius, which is quasi to linear permanent magnet synchronous motor. Based on Maxwell's equations, the Poisson's equations in the permanent magnet (PM) subdomain and the Laplace's equations in the subdomain between air gap and PM are calculated under no‐load condition. The radial and tangential flux density of each subdomain are obtained by the Fourier's series, hyperbolic functions, separation of variables, and the boundary condition. Better yet, the curvature coefficient is introduced to reduce the error between the analytical magnetic field in the planar model and the tubular model. The analytical no‐load magnetic field model is established more accurately. The expression of curvature coefficient and back‐electromotive force are derived. One prototype is manufactured for simulation and experimental study. The accuracy and feasibility of the proposed model are verified by the prototype test. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

To study the effectiveness of infrared and UV imaging technology to detect zero‐value insulators, the infrared thermal images and UV videos of zero‐value insulators at different positions on insulator strings were collected at different humidities and levels of pollution. The heat and discharge characteristics of the insulator strings were analyzed. The thermal‐electric multi‐physics simulation models were established with COMSOL Multiphysics finite element analysis software. The temperature and electric field distributions of the insulator string under different conditions were verified. The study shows that, under conditions of dry pollution, the insulator strings did not easily discharge, thus the UV imaging method cannot effectively detect a zero‐value insulator. The infrared thermal image shows that the temperature rise in a normal insulator is significantly higher than that in a zero‐value insulator; zero‐value insulators can thus be detected using infrared imaging. In the case of wet pollution, infrared and UV imaging may return erroneous results due to heavy pollution of high conductivity and unevenness of pollution owing to moisture. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

To study the influence of environmental factors such as temperature, humidity, wind speed, and air pressure on the detection of corona discharge using ultraviolet imaging, the rod‐plate gap model was used, and the ultraviolet video signals of AC discharge under different environmental conditions were recorded by CoroCAM504 ultraviolet imager, and the environmental factors affecting UV discharge from electrical equipment were analyzed. The experimental results show that the area of the discharge spot increases nonlinearly with temperature. The area of the discharge spot decreases with increasing humidity, and a power‐law relationship governs this behavior. At a humidity of 40 to 90%, the power index varies from 1.6 to 2.6. Wind speed weakens coronal discharge: when the wind speed is 12 m/s and the voltage is 50 kV the discharge spot area is reduced by 76.7% compared with that in still conditions. Air pressure has a significant effect on ultraviolet imaging, and field tests also show that discharge at high altitudes is stronger than that at lower altitude. Based on the above experimental research, normalization of spot area by correction coefficient method is proposed. The correction error is less than 20%, which offers guidance to engineering practice. © 2020 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper presents a novel distributed method for dynamic economic dispatch (DED) problems with cubic fuel cost functions based on the dual alternating direction method of multipliers (D‐ADMM) and interior point method (IPM). This scheme enables us to combine the excellent parallelism of ADMM with the superior convergence properties of the IPM. The idea adopted by the proposed algorithm is that the outer‐loop uses ADMM decoupling, and the inner‐loop uses IPM to solve the cubic polynomial optimization subproblems. When the unit set is divided into multiple partitions, D‐ADMM also has the nice central processing unit (CPU) runtime as the well as the number of iterations. In addition, we use a Decoupling‐Decomposition‐Backtracking and parallel improved multiple centrality corrections decoupling interior point method (DDB‐PIMCCD) to solve the aforementioned larger subproblems more efficiently. Finally, the numerical results, in both serial and parallel modes, on a set of 22 DED cases with the range of units from 8 to 1000 units show that the proposed method is very promising for large scale distributed DED problems. Because it can keep the unit information about each subset in secret to suit the market environment and can obtain high‐quality solutions with reasonable time. © 2020 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]