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In this paper, a novel AC magnetic transmitter current source circuit is proposed for application of frequency domain electromagnetic method (FEM) prospecting. The proposed current source circuit is capable of generating high frequency and high constant amplitude currents, which are key technical problems for FEM. It is suitable for very wide frequencies. The main circuit of the proposed current source consists of a rising-edge enhancing unit, a constant current control unit, and a high voltage clamping unit. Large constant clamping voltage is applied during the rising edge and the falling edge of the alternating square current to obtain a high frequency and high linearity current source. On the current flat stage, the constant current unit provides the energy to the load to ensure the constant amplitude of the output current. Detailed operations of the proposed magnetic current source are given. Simulation and experimental results demonstrate that the proposed circuit achieves short reversal time, the linearity of the rising/falling edge, constant amplitude and low power loss. These are the desired characteristics of the ac square current source probing transmitter for the magnetic FEM applications.
Xiujuan Wang; Zhihong Fu; Yao Wang; Wendong Wang; Wei Liu; Junli Zhao. A Wide-Frequency Constant-Amplitude Transmitting Circuit for Frequency Domain Electromagnetic Detection Transmitter. Electronics 2019, 8, 640 .
AMA StyleXiujuan Wang, Zhihong Fu, Yao Wang, Wendong Wang, Wei Liu, Junli Zhao. A Wide-Frequency Constant-Amplitude Transmitting Circuit for Frequency Domain Electromagnetic Detection Transmitter. Electronics. 2019; 8 (6):640.
Chicago/Turabian StyleXiujuan Wang; Zhihong Fu; Yao Wang; Wendong Wang; Wei Liu; Junli Zhao. 2019. "A Wide-Frequency Constant-Amplitude Transmitting Circuit for Frequency Domain Electromagnetic Detection Transmitter." Electronics 8, no. 6: 640.
The grounding grid is critical to the safety and stability of a power system. Corrosive cracking of the grounding conductor is the main cause of deterioration of grounding grid performance. Existing fault diagnosis methods for grounding grids are limited by the number and distribution of grounding leads, and some of them cannot be used for online detection. This paper proposes a grounding grid detection method based on magnetic source excitation. The measuring device consists of four coils, two horizontal excitation coils, and two vertical receiving coils. The secondary magnetic field signal is extracted from the primary field and the background field by properly positioning the coils, such that the measured signal can reflect the underground media more accurately. The measuring device of the method is portable, the measurement process is contactless with the grounding grid, and it is not limited by the grounding leads. Furthermore, it has a strong anti-interference ability and can realize online detection. It was proven by simulations and experiments that the proposed method has a higher measurement accuracy and stronger anti-interference ability when compared with existing methods. This paper also discusses the influence of various factors such as the number and the location of the breakpoints, the frequency of the excitation source, the soil resistivity, and stratification from the measurement data. It was proven that the method has high precision and a wide application range, and is important for guiding significance and reference value in engineering applications.
Xiujuan Wang; Zhihong Fu; Yao Wang; Renkuan Liu; Lin Chen. A Non-Destructive Testing Method for Fault Detection of Substation Grounding Grids. Sensors 2019, 19, 2046 .
AMA StyleXiujuan Wang, Zhihong Fu, Yao Wang, Renkuan Liu, Lin Chen. A Non-Destructive Testing Method for Fault Detection of Substation Grounding Grids. Sensors. 2019; 19 (9):2046.
Chicago/Turabian StyleXiujuan Wang; Zhihong Fu; Yao Wang; Renkuan Liu; Lin Chen. 2019. "A Non-Destructive Testing Method for Fault Detection of Substation Grounding Grids." Sensors 19, no. 9: 2046.