The Analysis On Excitation Characteristics Of Electromagnetic Transformer

The growing demand for electricity led to the rapid development of the power industry with the modern power grid transmission capacity, voltage levels rising, as well as power quality and safety and stability being constantly challenged. Electromagnetic transformer power system is still in a dominant position. Electromagnetic transformer has the same general structure of a transformer, which include the secondary side winding and the core composition.For electromagnetic transformer voltage frequency magnetic saturation has important implications, and therefore different transient excitation shows different excitation characteristics. Over-voltage is calculated by the excitation characteristics influence. In addition, the power system equipment selection and system protection methods should be considered to determine the excitation characteristics. More importantly, the electromagnetic transformer and system ground capacitance of the L-C circuit constituted short-circuit fault occurs in the system or perform certain actions, it will inspire a ferromagnetic resonance over-voltage which can cause injection transformer secondary voltage load damage, severe burning voltage transformers, causing widespread power outages, a serious threat to the safe operation of the system, resulting in huge economic losses. Therefore, in-depth study of electromagnetic excitation transformer characteristics, not only the actual production needs, but also has theoretical value.Based on the measured electromagnetic voltage transformer volt-ampere characteristic data, first using linear interpolation linear interpolation of the original data, increasing the number of data points, then use the method of least squares fitting excitation characteristic expression, and the measured values contrast. Based on this discussion of the influence of temperature on the excitation characteristics, the study found that the temperature is high, at the same excitation voltage, the magnetizing current is small, the excitation curve linearity better. Measured in the temperature range has found that excitation characteristic curve are able to meet the requirements of error of30%.Non-linear and capacitive elements in ungrounded systems are widely used, making the system constitutes an L-C circuit. Once the system is in a short circuit or ground fault switch on-off operation, it will make the system generated to stimulate the resonant frequency of ferromagnetic resonance, so that the system is in a resonant L-C circuit. Focus ferromagnetic resonance with the core of the capacitive element and the inductance of the resonance. Once the formation of ferromagnetic resonance will bring the power system failure can cause over-voltage and over-current. In this paper, particle swarm algorithm is used to detect the ferromagnetic resonance phenomenon with the application of matlab simulation, in order to find the excitation characteristics of ferromagnetic resonance phenomenon.