Thanks to Roger Tiktin of Lakewood for this hand from a duplicate event. His partner, sitting South was Erin Deloney of Mentor.
Without an explanation, the auction looks to be a little strange. Bidding techniques have come a long way and this hand is an example of what you can do if you have the right tools in your "bidding bag".
The opening one no trump was standard. Two hearts was a transfer to spades. Deloney's three diamond response was a conventional bid. The name of the convention is "Advanced Jacoby". When responder has a hand that they would normally make a "super" accept by jumping to the suit that they were being transferred to, they instead bid a new suit at the three level. The bid suit must be a doubleton. If they don't have a doubleton they cannot make a super accept.
Tiktin now knows that partner has at least four spades and only two diamonds. His jump to five hearts is called "Exclusion Blackwood". He is asking partner to tell him how many "key cards" she has excluding any cards in the heart suit. "Key cards" are defined as the four aces and the king of trump. Exclusion Blackwood is used when a trump suit has been agreed to (in this case by the super accept bid) and the partner asking for aces has a reason to exclude one suit from the interrogation.
Deloney bid five spades which is the next available bid and shows zero or three key cards. Five no trump would show 1 or 4 key cards, six clubs would show two key cards without the queen of trump, and six diamonds would show two key cards with the queen of trump.
Since it is highly improbable that the South hand has zero key cards outside of the heart suit, it is fair for Tiktin to assume that she is showing the three other aces. He can't actually count thirteen tricks, but he knows that he can start trumping diamonds in the dummy and as long as that suit doesnt' break worse than 4-1, he will be able to astablish his long diamonds.
The grand slam, bid and made, was an absolute top board because it is very difficult to bid a grand slam missing an ace. I would suspect that it would be difficult to get to a small slam on these cards. The point is, these are not difficult conventions and the average player who is already playing Jacoby Transfers and Blackwood could easily incorporate them into their game. And even if you don't decide to use them yourself, hopefully you will now know about them when they come up and the opponents use them.