The Federal Power Commission, which last summer nearly tripled the price of natural gas discovered after Jan. 1, 1975, announced yesterday that it would begin a proceeding to decide what price it should set for gas found after Jan. 1, 1977, and to review the price it set last summer.

The commission, which regulates the price of gas sold in a state other than that in which it is discovered, did not say that intended to raise or lower natural gas prices.

But each time it has reviewed gas prices in recent years, it has raised them, citing the need to stimulate exploration for natural gas and to encourage conservation of the cleanest of the fossil fuels.

Before last summer's ruling, natural gas discovered after Jan. 1, 1973, cost 52 cents per thousand cubic feet.

The commission ruled last summer that the price of gas discovered between Jan. 1, 1973, and Dec. 31, 1974, would be raised to 93 cents (and should go up a penny each Jan. 1 thereafter) and that gas discovered after Jan. 1, 1975, would cost $1.42 and would go up a penny each quarter.

That ruling has been challenged by a coalition of organized consumer groups, labor unions, state regulatory commissions and politicians. The U.S. Court of Appeals here will hold hearings on the challenge in the near future.

Until the court can rule on the FPC price ceilings, producers may charge the higher price but must make provisions to refund the difference between the higher price and the 52-cent price which prevailed before the FPC ruling.

The power commission has decided that it will review natural gas prices every two years.

The last time the FPC had a similar proceeding, it took it nearly two years to reach a decision on a new ceiling price. The agency said yesterday that interested parties have until Aug. 1 to comment on what proper rates should be.

The agency also requested comments by Oct. 1 on whether special allowances should be given for drilling deeper onshore wells and for drilling offshore in water deeper than 250 feet.