Thermal Response Time of LV Fuse Gear in Secondary Substations and Cable Distribution Cabinets

Low voltage (LV) fuse gear might experience higher peak loads due to the increased use of high power demanding equipment. To what extent these peaks will affect the temperature rise of the equipment, depends on the duration of the load peak, and the thermal time constant of the equipment. This paper presents temperature measurements of fuse gears in this part of the grid. Thermal time constants between 50-120 minutes were found. This implies that short duration load peaks will not significantly affect the temperature rise of the equipment. While longer duration load peaks due to e.g. charging of electric vehicles might challenge the thermal limits.