What the 1500 W rating means for your protection budget
The 1.5KE18CAH: That 1500 W rating means the device can absorb a single 60 A pulse (the Ipp at 25.5 V clamping) without failing — sizing the TVS to the energy of the expected transient, not just the steady-state voltage, is what keeps the downstream silicon alive. The clamping voltage maxes at 25.5 V at the full 60 A pulse — that is the voltage the protected circuit actually sees during the event.
Package and board integration — DO-201 axial
No power line protection is claimed — this is a signal-rail or low-voltage power-rail TVS, not a mains-side protector. The single bidirectional channel clamps both polarities, which is the usual choice for AC-coupled or bipolar signal lines.