star wars - Did Darth Sidious send Vader to Mustafar as an indirect way of protecting his own "Sith Master" status and power?

Sidious told Vader to go to Mustafar to end the Seperatist movement, but did he know that Obi-Wan would show up and defeat Vader based on his "vision" of future events? Was this Sidious' way of ensuring his power by encumbering (Vader's suit) his only true rival?

Answer

No.

Here’s a quote from the Revenge of the Sith script, just after his duel with Yoda:

CLONE COMMANDER THIRE: There is no sign of his body, sir.
MAS AMEDDA: Then he is not dead.
PALPATINE: Double your search.
CLONE COMMANDER THIRE: Yes sir. Right away, sir.

PALPATINE: (to Mas Amedda) Tell Captain Kagi to prepare my shuttle for immediate takeoff.
MAS AMEDDA: Yes, Master.
PALPATINE: I sense Lord Vader is in danger.

This menace to his apprentice is new for him, so he cannot have planned it.

As a complement, here a quote from Palpatine’s Wookieepedia article, specifically the Transformation of Vader section, which cites Star Wars Episode III: Revenge of the Sith (junior novelization) (emphasis is mine):

The battle between Kenobi and Vader had ended much differently. Kenobi had succeeded in grievously wounding his former apprentice, leaving him for dead. Hurrying to Mustafar with speed only the Emperor of the galaxy could afford (and with vigor that surprised even himself), Palpatine found his apprentice badly burned but alive. Sidious finds Vader's body scorched by lava after losing to Obi-Wan Kenobi on Mustafar.

Even as he made his way to the body, Sidious wrestled with anger and indecision. Part of him wanted to leave what was left of Vader to burn to ashes in the rising lava; even if he had survived, his body would be crippled, as would be his powers. Even the dark side of the Force required living beings to generate it, and too much of Vader's living flesh would have to be sacrificed in the act of saving him. Whatever the outcome, Vader would no longer be the perfect being to continue the Sith legacy, no longer be able to fulfill his promise. However, hobbled as he was, Vader would still be powerful, and there were no more Jedi to oppose him. So Sidious kept walking and, finally reaching his apprentice, placed a hand on Vader's forehead, using the dark side to keep him stable, while his shock troopers prepared a medical capsule for the return to Coruscant.