Northern Virginians will go to the polls Tuesday in a primary election to choose party nominees for the Virginia House of Delegates -- despite a ruling last week that the House redistricting plan under which the election is being held is unconstitutional.

A three-judge federal panel, ruling only two weeks before the primary, found that the plan did not conform to "one-man, one-vote" guidelines established by the U.S. Supreme Court, but nonetheless allowed Virginia to hold elections this fall. The panel ruled, however, that legislators elected this fall can serve only one year, instead of two, and ordered the General Assembly to complete a new redistricting plan by Feb. 1, 1982.

The latest ruling further amplifies the frustration that has dominated this year's races more than any other issue. Faced with the prospect that elections might be delayed, or even scrapped, or that districts could change radically, many House campaigns have been marked by a sluggish and hesitant pace.

Several House candidates say they have held off printing campaign literature.And money, they say, has been harder to raise than in previous years. In addition, several candidates contend that the short period between the primary and the general election, which is set for Nov. 3, has given incumbents, with their better name recognition, an additional bonus. All 19 House incumbents in Northern Virginia are seeking reelection.

"The reapportionment plan has created confusion across the political spectrum," explained Steven Yeakel, a Republican political strategist. "The uncertainty over it has crippled the race in almost every way."

The plan ruled unconstitutional by the special judicial panel gives Northern Virginia 21 delegates in the 100-member House, two more than the area currently has. Fairtax County, divided into four House districts, gains two seats and Loudoun County gains one. Alexandria and Arlington lose one representative through elimination of the joint "floater" seat.

The big winners in the court decision, political analysts say, probably will be the Republicans. As Arlington and Alexandria continue to suffer population losses, analysts say, political power is shifting from traditionally liberal, urban areas to the growing suburban centers, which increasingly have become fertile ground for conservative Republicanism.

Already, Republicans hold nine of the 19 Northern Virginia House seats, and with the addition of the three seats in Fairtax and Loudoun counties and the loss of the floater seat -- traditionally one of the most liberal seats in the state -- Republicans expect to make deeper inroads into the Democratic-dominated House.

Not surprisingly, however, few Republican House candidates in Northern Virginia are scrambling to sail into office on Ronald Reagan's coattails. Although Reagan carried parts of the area by 2-to-1 majorities, Northern Virginia stands to suffer some of the state's highest losses under Reagan budget cuts. To fully endorse the budget policy, many Republican House candidates concede, could alienate many of their constituents.

Instead, as in previous races, few issues have separated the candidates -- Republican or Democratic -- and the money debate has focused on the long-standing issue of Northern Virginia versus the rest of the state. Almost without exception, Northern Virginia candidates insist the area does not get its fair share of state funds, and most say they will fight for more Metro and highway funding.

* Three Northern Virginia jurisdictions -- Arlington County, Fairtax County and Prince William County -- will hold primaries Tuesday. There are no primaries for either party in Loudoun County and Alexandria. In addition, there are no Democratic primaries in two Fairfax County districts -- the 50th, which covers northwestern Fairfax, and the 51st, which covers southwestern Fairfax.

* Polling hours Tuesday are 6 a.m. to 7 p.m. in all jurisdictions.

* Registered voters who have not moved since the election last November or who have filed address changes are eligible to vote. The last day to register to vote in the primary was Aug. 8.

* Voters wishing to cast an absentee ballot should do so in person by Sept. 5 or request an application by today from their local election boards.

* Although Virginia does not require voters to register by party, you must declare which party ballot you want in order to vote in the primary.

* For more information about voting, contact your local election headquarters:

Arlington -- 558-2345.

Fairfax County -- 385-8100.

Prince William County -- (703) 368-9171.