The NBD (D = SQUARE D) range comes from the Compact NB range which originated from the Compact NS range. Previously the Easypact range covered amperages till 400A so for higher ratings than what Easypact 400 could have offered and for lower specs than Compact NS, =SE= introduced the Compact NB/NBD range.
Compact NBD630H (H stands for 36 kA) can nowadays be replaced by Easypact 630 (EZC630H). This is not a 1:1 substitute, however. There are some differences in terms of size and electrical characteristics.