Experimental Study of Relationship Between Arc Light Intensity and Temperature in Low-Voltage Switching Devices

Arc motion in a quenching chamber has a significant influence on switching performance in a low-voltage switching device (LVSD). A high-speed optical arc imaging system (AIS) has been used to investigate the influence of the design parameters of a quenching chamber on arc motion. Arc light intensity is transmitted to the photodiodes of the AIS through optical fibers during the switching process. The AIS and associated software enable the detailed arc motion to be tracked inside the chamber at an image sampling rate of 1 MHz. Since higher arc temperature leads to greater radiation, it is assumed that the arc light intensity measured by the AIS is related to the arc temperature. However, there has been a little empirical study of the correlation between the arc temperature and light intensity measured by the AIS. In this article, the relationship between the arc temperature and light intensity is investigated by measuring arc spectra and arc images. Arc spectra are captured by a spectrometer when the arc is ignited by copper wire in a narrow enclosed chamber, and they are used to calculate the arc temperature by the Boltzmann plot method. At the same time, the AIS records the arc images from points adjacent to the fiber of the arc spectrometer. It is found that the arc light intensity measured by the AIS is directly related to the arc temperature; the correlation between the fourth power of temperature and the light intensity is an approximately linear trend.