In a decision that could affect pipleine rates nationwide, a federal administrative law judge yesterday ruled that the Alaskan oil pipeline owners must refund $752 million in excessive transportation charges.

Judge Max L. Kane also ruled that the methods used to set oil pipeline rates in the United States since 1941 are "an artifact of a bygone era" that awards excessive returns to the oil companies.

Kane's decision would, in effect, refund most of the money to the majority pipeline owners, who also produce oil on Alaska's North Slope. It must still be approved by the Federal Energy Regulatory Commission. The FERC ruling is expected in the next three months.

A FERC spokesman said that consumers would not get any of the refunds if Kane's decision is upheld, but Alaska would be eligible for 12.5 percent share of it.

"in the future, however, a lower pipeline rate could translate into lower consumer oil prices in the lower 48 states," FERC's Barbara King said.

Fifteen percent of the nation's domestic oil production, slightly more than 1.2 million barreels a day, is carried through the 800-mile TransAlaska Pipeline. The pipeline is owned by the three principal North Slope producers, Atlantic Richfield, Standard Oil of Ohio and Exxon, along with Mobil, Phillips, Union Oil of California, British Petroleum and Amerada Hess.

Kane's 138-page decision recommended that the commission lower the pipeline's rates from an average of $6.20 a barrell to $4.93 in 1978, and $5.67 in 1977, the first year of the pipeline's operation.

Responsibility for oil pipeline regulation was transferred to FERC from the Interstate Commerce Commission by Congress in 1977.

Judge Kane rejected the ICC oil-pipeline tariff methodology now in use throughout the United States in favor of FERC's formula for setting natural gas pipeline rates. This formula gives the industry lower profits.

The ICC tariff formula has come under repeated broad attack from the Justice Department, the General Accounting Office and the Federal Trade Commission in recent years as unfair and uncompetitive.

A federal court of appeals also has ordered FERC to review the ICC oil formula to determine whether it results in excess profits.

Kane's ruling is a major step in that process, and is expected to shape FERC's final decision on future nationwide oil pipeline rates.

Yesterday Standard Oil Co. of Ohio issued a statement saying that the FERC law judge opinion is still an "interim " finding and that the company will oppose it before the commission. If FERC upholds Kane, the statement added, the company will appeal to the courts.