The Virginia General Assembly imposed major restrictions yesterday on the right of electric utilities to pass on fuel costs to their customers and passed three other measures intended to hold down electricity bills.

The final action on the utility bills came shortly before the assembly moved toward adjournment of its 60-day, 1978, session.

Restrictions on the pass-through of fuel costs to utility customers through a regulatory device known as the feul adjustment clause has been a major goal of consumer organizations in recent years and was an issue in last year's gubernatorial election. The bill approved yesterday closely resembles legislation submitted to the assembly by Gov. John N. Dalton.

Inflation in the costs of coal, oil and nuclear fuels used to generate electricity have accounted for most of the near doubling of electricity prices since the Arab oil embargo five years ago.

However, such organizations as the Consumer Congress of the Commonwealth of Virginia and the Virginia Citizens Consumer Council have increasingly complained that utilities are passing on not only higher fuel costs but also the costs of poor performance by large nuclear and coalfired power plants.

Under existing regulations, Virginia Electric and Power Co., the state's largest utility, is permitted to charge customers for using more expensive oil to generate power when its two nuclear power or large coal-fired units are out of service.

The bill passed by the assembly will require Vepco and other utilities in Virginia to estimate each year how much emergy all ot its plants - coal, nuclear and oil - should produce. Once these projections are approved by the State Corporation Commission, the agency that regulates utility rates, the utilities could not pass on costs that result from failure of plants to measure up to promised productivity.

The bill, as it passed the House of Delegates, directed the SEC to require generating plants in Virginia to perform at least as well as the national average of productivity for such plants.

However, neither consumer nor utility lobbyists considered the national averages to be meaningful test and the Senate amended the bill to let the SCC adopt "reasonable" productivity standards.

Although the fuel adjustment restriction is the most significant utility measure passed by the assembly since electricity prices began to rise rapidly in 1974, supporters of the bill have warned that it will not bring about a reduction in utility bills. They hope, however, that it will provide an incentive for better performance at generating plants and improve consumer confidence in the regulatory system.

Two other utility measures passed by the assembly would require power companies to use, when practical, competitive bidding in their construction programs and would give the SCC the right to order studies of power plant construction programs. Cost of the studies of power plant construction programs. Cost of the studies would be paid for by the companies and passed on to consumers.

A fourth bill is designed to lower electric rates for churches by giving them a choice between residential rates and rates based on time of use.

The House also gave final approval to a bill prohibiting cities and counties from enacting container deposit ordinances as a means of controlling litter and conserving energy. The House accepted a Senate amemdment that would permit Fairfax and Loundin counties to retain existing deposit ordinances while they are being challenged in state courts.

The Assembly, which elected state court judges, filled on egeneral district court vacancy in Fairfax County, but failed to agree on a choice for an open district court judgeship in Prince William County.

Elected to a six-year term in Fairfax was former Assistant Commonwealth's Attorney F. Bruce Bach.

The Prince William judgeship was left to open when Sen. Charles J. Colgan (D-Prince William) and Del. Floyd C. Bagley (D-Prince William) could not agree on a candidate. Bagley supported MacDougal Rice and Colgan nominated Frank Hoss Jr., both Prince William lawyers. Failure of the House and Senate to agree on a nominee leaves the choice up the circuit court judges for the county.