What the 1500W rating means for your rail protection
The 1.5KE100AT/R: That 1500W figure is the energy it can absorb in a single surge event without failing — for a 137V clamp, that translates to about 11A of peak pulse current. The 85.5V reverse standoff voltage is the DC rail voltage the part sits across without conducting; pick this above the normal operating voltage of the line you are protecting. The 137V clamp is where the diode forces the surge voltage to stop rising — it must stay below the downstream component's absolute maximum rating.
Operating junction temperature spans -65°C to 175°C. That covers the full industrial temperature band plus automotive underhood environments where ambient can hit 125°C and the part self-heats during a surge. The 175°C TJ max means the 1500W rating holds at elevated temperatures — derating only kicks in above 25°C ambient per the standard TVS derating curve, but the headroom is generous.