There has been vs There had been

Question

How and where should we use "There has been" and "There had been"?

For example, I cannot recognize the semantic difference between the two following sentences:

There had been such a fortunate occurrence.

There has been such a fortunate occurrence.

In general, I know the grammars of past perfect and present perfect, but the translator translates them (the above examples) alike!

Answer 1

There had been such a fortunate occurrence.
Something amazing had happened. For a day, money dropped from the sky!

This recounts an event that happened in the past but has now passed.

---

There has been such a fortunate occurrence.
Something amazing has happened. Money is dropping from the sky!

This recounts an event that started in the past but is still ongoing.