The 1.5SMCJ130 is a unidirectional Zener-based TVS (transient voltage suppressor) diode — one channel, surface-mount, in the DO-214AB (SMC) package.
Standoff, breakdown, and clamping — the three-voltage decision
130 V reverse standoff (typ) is the working voltage below which the TVS stays off and draws only leakage current. The circuit should never see continuous DC voltage above this value in the blocking direction. 144 V minimum breakdown is where the TVS first begins to conduct — above this the Zener avalanche kicks in. The device guarantees it has turned on by the time the voltage reaches this floor. This is the number that goes into your protection-level calculation: the downstream IC or bus must survive 231 V briefly, or you need a second stage. The 10/1000 µs wave shape means a 1 ms rise / 1000 ms fall — a relatively long-duration transient compared to an 8/20 µs lightning surge, so the 1.5 kW rating is conservative for short spikes.