A device for measuring the temperature of a fuse in a capacitor

Abstract

The invention provides a fuse temperature measuring device in a capacitor, comprising an AC constant current source, a fiber grating sensor unit, a fiber grating signal demodulator and a monitoring host; the fiber grating sensor unit is embedded between capacitive elements inside the capacitor, and Reliable contact with the fuse in the capacitor; the fiber grating signal demodulator is connected between the fiber grating sensor unit and the monitoring host; the monitoring host receives the temperature data of the temperature measurement point of the fuse in the capacitor output by the fiber grating signal demodulator, and The fuse temperature measurement point in the capacitor will give a temperature alarm. Compared with the prior art, the device for measuring the temperature of the fuse in the capacitor provided by the present invention can accurately measure the temperature of the fuse in the capacitor under actual operating conditions, provide a basis for the design and selection of the fuse in the capacitor, and effectively Improve the reliability of the internal fuse protection action to ensure that the temperature of the internal fuse will not cause damage to the internal insulation of the capacitor.

Description

technical field [0001] The invention relates to a capacitor temperature measuring device, in particular to a capacitor internal fuse temperature measuring device. Background technique [0002] Power capacitors are mainly used for reactive power compensation of power systems to improve power factor. In order to make it operate more reliably, the current industry mainly considers connecting internal fuses in series with the internal components of the capacitor. When the capacitor fails completely due to dielectric weakness, the internal fuse connected in series with the component will act, so that only a part of the damaged component is isolated, and the capacitor will continue to operate with only a slight power reduction. At this time, the disturbance in the capacitor bank can be ignored, and the total capacity of the capacitor bank will not be significantly affected by the action of a fuse. The introduction of the internal fuse protects the capacitor elements, but virtuall...

AI Technical Summary

Problems solved by technology

At this time, the disturbance in the capacitor bank can be ignored, and the total capacity of the capacitor bank will not be significantly affected by the action of a fuse. The introduction of the internal fuse protects the capacitor elements, but virtually increases the fault point

[0003] Inside the power capacitor, the internal fuse is the main heating point, but the volume and diameter of the internal fuse are very small (about 135mm in length and 0.45mm in diameter), and are generally hidden between capacitor elements, which is limited by the current measurement technology , it is difficult to truly and objectively measure the surface temperature of the inner fuse under actual operating conditions

[0004] At present, the temperature measurement method for the fuse temperature used in the internal protection of power capacitors includes a temperature rise test, but this test only estimates the temperature rise of the internal fuse by measuring the current and resistance of the internal fuse, and its accuracy is poor. During the flow process, the resistance of the internal fuse will change with its temperature. On the one hand, it is difficult to ensure a constant flow. On the other hand, the corresponding relationship between the internal fuse resistance and temperature is only applicable within a certain temperature range. It will be difficult to get accurate results beyond this range, so this method of indirectly measuring the temperature rise of the fuse in the capacitor has limitations and is not very accurate

In addition, the thermal resistance is used to measure the temperature rise of the internal fuse, but since the thermal resistance is much larger than the internal fuse in terms of volume and diameter, it will affect the actual temperature of the internal fuse during the contact measurement of the temperature of the internal fuse. Influenced by temperature, the measurement accuracy is even worse

Images