What the 1500W rating means for your board
The 1.5KE100A-T is a 1500W (1.5kW) peak pulse power TVS diode in the standard DO-201AA axial package. That 1500W rating is the peak power it can absorb in a 10/1000µs waveform — enough to clamp a 137V transient from an 85.5V rail down to a level that won't punch through downstream silicon. At the 11A peak pulse current (Ipp), the clamping voltage maxes out at 137V. The breakdown voltage starts at 95V minimum, so a 100V-rated bus gets protection that triggers before the rail hits destructive levels.
Obsolete — sourcing reality for this part
Diodes Incorporated lists the 1.5KE100A-T as obsolete. For a repair bench or a BOM line that needs this exact number, the path is through independent surplus or broker channels.
Package and temperature envelope
Through-hole DO-201AA (DO-27 axial) package, single unidirectional channel. No power line protection (it's a unidirectional TVS, not a rail clamp array), so it's best placed across a DC bus or signal line where a single transient event needs a hard shunt to ground.