According to the wavelet-neural network algorithm of relay protection device has the characteristics of requirement of high sampling frequency and large amount of data calculation, we use FPGA to realize the algorithm in hardware. A system model is built and converted into VHDL code through the system-level digital signal processing development tool named DSP Builder from Altera Company. We verified the correctness and feasibility of the method by the timing simulation diagram get from Modelsim SE software. This paper implemented protection method of the wavelet transform and neural network with hardware, and completed a series of research work in the field of transformer differential protection.
This paper elaborates the DC screen and battery DC screen fault detection method. The method of measuring battery’s internal resistance and voltage is analyzed and studied in this paper, and the two methods are optimized. Besides, the structure of the battery internal resistance, internal resistance equivalent principle and other aspects are also introduced in this paper. The optimal measurement scheme can be chosen by comparing the internal resistance measurement of DC discharge method and the AC signal injection method.
To improve accuracy and speed of recognising and classifying grid power quality disturbances, this paper presents a new method which combines complex wavelet transform and particle swarm optimization (PSO) neural network to identify and classify the disturbance . This method extract both amplitude-frequency and phase frequency information of the interference signal to make up for the lack of traditional wavelet transform which only extract the amplitude-frequency information. And on this basis, using particle swarm optimization, we seek the optimal solution of neural network weights and thresholds for the identification and classification of power quality. The MATLAB simulation result has verified the accuracy and rapidity of this method compared with the traditional method .
A unified control method of comprehensive compensation system based on CS- APF and SVC is introduced in this paper. SVC is composed of thyristor controlled reactor (TCR) and fixed capacitor (FC). For the CS- APF control, a feedforward control for harmonic compensation of SVC and load is applied. The CS- APF is enabled to optimize the var compensation performance of SVC. Finally, the simulation results show that the system can effectively compensate reactive power and eliminate harmonic currents.
A smart meter was designed with power line communication (PLC) function. We designed the optimized power carrier module by adding a switching circuit that controlled by a microcontroller in coupling circuit on the basis of common design. Improved its communication efficiency and reduced energy consumption. Energy metering module used C8051F360 microcontroller as the main control chip and used high accurate metering chip ATT7022B to collect electronic signal. We designed a multifunctional and easy-to-use intelligent man-machine interface by using Beijing DWIN Company’s industrial serial LCD touch screen.
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