To avoid failures in circuit breakers (CBs) and to extend the lifetime of these critical components, condition-based-maintenance has been increasingly requested by utilities to enable them to efficiently manage their assets. The origin of the most failures in CBs is the operating mechanism. Travel curve (TC) could effectively reveal the condition of the operating mechanism. However, the measurement of a TC profile is not simple in all CBs. This paper presents the impacts of common failure modes of CBs on TC profiles, and proposes a new model-aided approach to simulate the behavior of the operating mechanism with coupling the model-based and rule-based approaches. The simulation results along with experiments conducted on 72.5 kV SF6 CBs are organized into a fuzzy-probabilistic approach through maximum likelihood and interacting multiple models (IMM) to precisely predict the condition of CB and to detect intelligently the cause of the failure. For this purpose, the CB condition has been categorized into three modes based on its operating speed: normal (about 3 m/s), faulty-1 (less than the normal range), and faulty-2 (more than the normal range). The mode variations of the CB have been estimated via IMM in each operation. The proposed approach in prediction of the failures and cause(s) prior to their occurrence has been verified against experiments.

A Probabilistic Model-Aided Failure Prediction Approach for Spring-Type Operating Mechanism of High-Voltage Circuit Breakers

This paper reports an energy-efficient permanent magnet (PM) zero-holding-energy magnetic contactor (ZMC) that consumes no energy while maintaining an open or closed state. Conventional solenoid magnetic contactor (MC) technology has several critical drawbacks, including high continuous energy consumption, continuous vibration, and low reliability. The proposed ZMC substantially reduces energy consumption and heat generation, produces no vibration, and provides increased reliability. Traditional MC analysis typically requires computationally expensive finite element analysis (FEA). To reduce the analysis costs, a recently proposed fast and accurate nonlinear transient path energy method (NT-PEM) is utilized to significantly reduce analysis time and costs. Analysis accuracy was verified experimentally using a fabricated ZMC prototype. The economic and environmental benefits of the proposed ZMC confirm its significant potential as an energy-efficient eco-friendly alternative to traditional MC technology. ZMC is particularly promising for vehicular micro-grids due to the prolongation of the lifetime of batteries owing to reduced energy consumption.

Energy-Efficient Eco-Friendly Zero-Holding-Energy Magnetic Contactor for Industrial and Vehicular Applications

Improving the efficiency and end-use of energy distribution can significantly reduce global energy consumption. As the magnetic contactor (MC) is the most common switchgear used for control in most grids, minimizing its energy consumption has motivated the development of a permanent magnet (PM) MC that exhibits several advantages over conventional solenoid MCs. However, analyzing the transient magnetic behavior of a PM MC requires computationally expensive 3D finite element analysis (FEA). Herein, a modified version of a recently proposed nonlinear transient path energy method (NT-PEM) is proposed as an analytical alternative to FEA. Within the modification to NT-PEM, a new topology for nonlinear dynamic magnetic equivalent circuit (ND-MEC) is proposed with a methodology for accurate evaluation of stray and leakage flux path parameters. For coil leakage reluctances, a novel path function based on a conchoid’s arc is proposed. For stray reluctances, a path function based on the average length of an elliptical arc is proposed. This path function, along with the proposed permeability correction for nonlinear core reluctance calculation routines, led to a four-fold reduction in NT-PEM analysis time from the original version of the proposed method. The feasibility of the proposed NT-PEM is verified via comparison with commercial 3D FEA and experimental data obtained from a PM MC with a single coil and single PM. NT-PEM and FEA equally displayed accurate results, indicating that NT-PEM is a promising computationally efficient alternative to FEA owing to significantly reduced analysis time, which is essential when considering numerous designs and design parameters.

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Analysis of Nonlinear Dynamics of Permanent Magnet Magnetic Contactor via Novel Computationally Efficient Analytical Method Considering Stray and Leakage Fluxes

The invention discloses a movable platform calibration device based on visual recognition. The movable platform calibration device is used for calibrating the advance direction and/ or the centre of gyration of a movable platform. The movable platform calibration device comprises a camera shooting unit and a calculation unit, wherein the camera shooting unit obtains image towards a working plane, and records the coordinate of a gauge point in the image, wherein the gauge point is arranged on the working plane and is positioned in the view range of the camera shooting unit in a movement process of the movable platform; and the calculation unit obtains the coordinate of the gauge point from the image, and fits a plurality of gauge points in an image coordinate system to obtain the movement tracks of the gauge points in the image. The movable platform calibration device only utilizes a visual sensor to accurately calibrate the advance direction and the centre of gyration of a mobile robot on the premise that other sensors or positioning ways do not need to be used so as to be favorable for improving the stability and the reliability of the mobile robot in the movement process and be favorable for lowering the production and research and development cost of the robot.

Movable platform calibration device and calibration method based on visual recognition

The invention discloses an object planar motion measuring device and an implementation method and particularly relates to a measuring device for measuring object planar motion through laser range sensors. The planar motion measuring device utilizes the three laser range sensors, achieves non-contact measurement of object planar motion through a measurement combination algorithm and eliminates interferences of the self-motion of the measuring device in the motion of a measured system. The non-contact type object planar motion measuring device has the advantages of being high in measurement accuracy, simple in structure, convenient to install and easy to maintain.

Non-contact type object planar motion measuring device and implementation method thereof

The characteristics of arc in DC contactors are a major factor affecting the breaking performance of small-sized contactors. Based on the magneto hydrodynamics (MHD) model, this paper obtains the temporal and spatial distribution of arc temperature by taking DC arc as its research objective and H 2 , N 2 and He as arc extinguishing media. A removable arc chamber was adopted to build up a DC experimental circuit, in which a double-contact structure made of pure copper was selected, with a contact diameter of 10mm and a contact spacing of 2mm, to measure the influence of magnetic field, pressure and breaking speed on the characteristics of DC arc. The simulation and experimental results suggest that H2 has a stronger arc extinguishing capability than N2 and He when used as an arc extinguishing medium for switches; the increase in pressure contributes to the reduction in arcing time but the reduction is not monotonic, and a pressure of 3–4atm is desirable; the increase in magnetic flux density and breaking speed can effectively shorten the arcing time, and a breaking speed of 0.5m/s and magnetic flux density of 50mt are desirable.

Study on factors influencing the characteristics of arc in DC contactors

The invention belongs to the field of mobile positioning of intelligent robots, and particularly relates to a device for positioning the running track of a mobile robot and a method for positioning the running track of the mobile robot. The device for positioning the running track of the mobile robot comprises a central processing unit, a gyro for measuring the rotation angle of the robot, and a sensor for measuring the displacements in the horizontal and vertical directions, wherein transmission ports of the gyro and the sensor are connected with a transmission port of the central processing unit respectively; the sensor employs an optical sensing device or a photoelectric encoding device; the optical sensing device comprises an optical imaging engine and mainly comprises a complementary metal oxide semiconductor (CMOS) image sensor and an optical positioning digital signal processor (DSP) module; and the optical positioning DSP module is in charge of analysis and comparison of adjacent image matrixes so as to compute the horizontal and vertical moving distances of the robot within a unit time. By the method and the device, the moving track of the robot can be precisely positioned without the help of external equipment.

Method and device for positioning mobile robot and recording running track of mobile robot

The utility model discloses a locating device for a running track of a mobile robot The locating device comprises a digital gyroscope and an optical sensing device or a photoelectric coding device The angular speed of a robot during rotating is measured by using the digital gyroscope, a measurement result is integrated, thus the angle where the mobile robot rotates is solved; the walking distance of the robot is measured by using the optical sensing device, and the optical sensing device is realized by adopting a photoelectric mouse; or the walking distance of the robot is measured by adopting the photoelectric coding device, and the photoelectric coding device is realized by adopting a roller type mouse

Locating device for running track of mobile robot

In order to improve the heat dissipation performance and study the factors affecting the heat dissipation effect of a two-dimensional ordered porous structure, a thermal analysis of the radiator in the power module of a DC charging pile was carried out. Based on the thermal analysis of the grid-type radiator, the square-hole radiator is subjected to a thermal analysis, the heat dissipation performance of the two radiators is compared, and the factors affecting the heat dissipation effect of the square-hole radiator are explored. Research shows that the heat dissipation effect of the square-hole radiator, which represents a twodimensional ordered porous structure, is better than that of the grid-type radiator. The factors affecting the heat dissipation effect of the square-hole radiator are mainly related to the height of the radiator and are positively related to the heat dissipation effect of the radiator.

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Thermal analysis of electric vehicle DC charging pile power module based on two-dimensional ordered porous structure radiator

It is necessary to monitor the operation state of the High voltage circuit breaker (HVCB) and analyze the fault by the related signal, the fault of HVCB operating mechanism is closely associated with coil current, mechanical vibration and other factors. The method of fault diagnosis for HVCB based on Hilbert-Huang transform (HHT) and support vector machine is proposed to analyze faults accurately and quickly in high voltage circuit breakers, determining the characteristic and category of the fault. HVCB testing platform based on LabVIEW and acquisition equipment gain the signals of mechanical vibration. The model of fault diagnosis for HVCB is established by using support vector machine (SVM). The data are trained by SVM, thus the type of fault can be clearly determined. The method can obtain better diagnosis results, it is also suitable for fault diagnosis for HVCB.

Ying Han

Papers

Study on factors influencing the characteristics of arc in DC contactors

Method and device for positioning mobile robot and recording running track of mobile robot

Locating device for running track of mobile robot

Thermal analysis of electric vehicle DC charging pile power module based on two-dimensional ordered porous structure radiator

Fault diagnosis for high voltage circuit breaker based on Hilbert-Huang transform and support vector machine