Hou Chunguang

Design on permanent magnet actuator and simulation of dynamic characteristic for vacuum circuit breaker

A novel Permanent Magnet Actuator (PMA) is put forward in this paper. The 3D magnetic distributions of PMA in different conditions have been computed, adopting ANSOFT9.0 software. In order to determine the size of each part of PMA, the variations of each parameter haw been simulated in dynamic course of breaking and closing. Based on the simulation results, the prototype is manufactured and assembled. The feasibility of the proposed PMA and the simulation veracity of the dynamic characteristic of breaking and closing hare been proved by the tested data of the prototype.

Research on a novel on-line monitoring system for Mechanical Characteristic of Circuit Breaker

Detection Device of Circuit Breaker (CB) Mechanical Characteristic is established in the paper, which takes TMS320F2812 as a core, and makes a logic extension. The necessary signal is collected, stored, and transmitted to position machine Upper memory block through CAN bus. The signal is analyzed and disposed, and the experimental data is transported to remote monitoring machine, thus the date is accumulated and information is shared. The paper improves maintenance level of CB, realizes the condition maintenance of CB, and enhances the efficiency of detection, so that this design has very important theoretical meaning and practical value.

Analysis on vibration and acoustic joint mechanical fault diagnosis of high voltage vacuum circuit based on wavelet packet energy relative entropy

In view of the requirement of high reliability and small disturbance in the condition of high-voltage (HV) vacuum circuit breaker (VCB), this paper puts forward a method of fault diagnosis based on online monitoring of vibration and acoustic signal. The research object is the 12kV indoor high-voltage vacuum circuit breakers and the system of fault diagnosis of the research object is built. This method uses fast kernel independent component analysis to make blind source separation processing for acoustic signals collected when HV VCB switch on. The wavelet packet energy should be calculated in each frequency of the vibration and acoustic signal. Support vector machine with the wavelet packet energy relative entropy as input vector to classify the common states, such as the normal condition, insufficient lubrication of the crank arm and mechanism fall off in moving. Experimental study has shown that, according to research on the characteristics of the vibration and acoustic signal generated by the circuit breaker, the proposed method can differentiate between normal working state and failure state and meet the high reliability of HV VCB status monitoring requirements.

Development of on-line monitoring system of switchgear

For improving reliable operation of switchgear in power system, an approach for on-line monitoring the insulation characteristic and bus-bar temperature rising of the switchgear is proposed in this paper. Through comparing several existing temperature measurement methods for monitoring temperature rising elevation at bus-bas, a new design of temperature monitoring method is proposed. It adopts quick-magnetic saturated current transformer, temperature sensor and infrared transmission to solve the problem of high voltage isolation. For switchgear insulation characteristic monitoring, using the micro-controller unit (MCU) and hardware design, an on-line dielectric loss angle and leakage current measuring method with low cost and high accuracy is implemented. Sensor and signal conditioning circuit design are adopted to ensure the accuracy of leakage current measurement. The frequency voltage signal is extracted by connecting voltage-dividing capacitor on capacitive device terminal and absolute method of measurement and zero-crossing comparison measurement is adapted to measure dielectric loss angle whose principle and calculation approach are presented in this paper. The leakage current and dielectric loss angle can be regarded as criterion to assess switchgear insulation characteristic. Because the monitoring system works in several electromagnetic interference environments, some hardware and software electromagnetic immunity measures are discussed. At last, the system runs in real system and the result shows the on-line monitoring system is stable and reliable which can be provide reference for on-line monitoring system design of switchgear.

Design and research of high stability repulsion mechanism of 12kV vacuum circuit breaker

Using finite element simulation method to carry a comparative analysis of the repulsion mechanism and permanent magnetic mechanism, come to the conclusion that the repulsion mechanism has the advantage of rapidity;Aiming at the problem of high speed easy to cause instability, presenting a design of adding coil and repulsion chassis on the basis of the original repulsion mechanism, and optimizing the material of the repulsion chassis;On the basis of this, the experimental prototype is designed and manufactured, and a number of switch test is conducted, measuring the breaking time of each break-barking test and compared with the simulation results to verify the accuracy of the simulation results; The time dispersion of the break-brake is calculated, verifying the high stability of the novel repulsion mechanism.

Research on fault diagnosis of operating mechanism for 12kV vacuum circuit breaker based on PSO-LSSVM

The small fault samples and single characteristic parameters in vacuum circuit breakers (VCBs) would lower the accuracy and reliability of mechanical fault diagnosis. In this paper, the problem has been solved with applying a fault diagnosis method based on particle swarm optimization (PSO) and least square support vector machine (LSSVM). By analyzing the close coil current (CC) of VCB, the eigenvalues of time and current are extracted as input vectors. The paper uses PSO to optimize the model parameters of LSSVM, which are important to fault diagnosis, and to select the best subset of eigenvectors to obtain the optimal performance of LSSVM classifier. Then the improved support vector machine (SVM) is used to train and test the eigenvectors and different states of VCB are classified. Results show that the proposed method can detect whether VCB is normal or not. And the validity and accuracy is verified.

Prediction of synchronous closing time on permanent magnet actuator for vacuum circuit breaker based on PSO-BP

In order to improve the prediction accuracy of phase controlled switching operation time, restrain overvoltage and inrush current when the circuit breaker switched on, this paper establishs BP network prediction model based on voltage and ambient temperature as the main input parameters, and weights the uncertainty influence factors such as aging and wear. In order to improve the accuracy of prediction model, proposing a method of BP neural network based on particle swarm optimization (PSO), comparing network prediction performance before and after algorithm optimized. The research results show that use the BP neural network based on PSO is more accurate than the prediction results which only by BP neural network predicts, the error of BP neural network based on PSO can control the predictive error within 0.2% and meet the requirement of synchronization control.

Investigation on current protection model for a vacuum circuit breaker

Based on the analysis of the existing current protection model, a reverse time limit current protection model according to the temperature rise has been put forward. The feasibility and wide application of the proposed current protection model have been verified by testing and analyzing the experimental results of the vacuum circuit breaker assembled with the permanent magnetic actuator.