I like to use SUMPRODUCT instead of SUM. The syntax is similar, but it's not an array formula - just press [Enter].

=SUMPRODUCT(1*(D2:D15>=30000), 1*(D2:D1550000), D2:D15)

You need to use 1*(...) to convert True and False to 1 and 0. That's the only annoying thing, as far as I'm concerned.