The second most powerful figure in Angola, Interior Minister Manuel Alexandre Rodrigues, met Vice President Bush at the White House yesterday morning, but close-mouthed administration sources said that no breakthrough is at hand on the withdrawal of Cuban troops from that south African country.

Rodrigues, who met Wednesday with Secretary of State George P. Shultz, held an hour-long meeting with Bush that a vice presidential spokesman called "very friendly." No details were given at the White House or at the State Department.

A plan for the withdrawal of the 25,000 Cuban troops from Angola is considered by the Reagan administration to be essential in obtaining South African withdrawal from the territory of Namibia, which borders Angola. At a news conference Tuesday, Shultz reiterated this connection, saying that "some sort of program" for the withdrawal of Cuban forces from Angola is necessary to provide South Africa with confidence in the security of the area.

Angola and a number of other African nations maintain that the withdrawal of South Africans from Namibia should not be linked to the withdrawal of Cubans from Angola. Nonetheless, informed sources said the question of the Cubans has been repeatedly discussed in more than 10 meetings between U.S. and Angolan officials during the Reagan administration.

The Angolan government and its friends insist that the Cubans are essential to Angola's security. In this view, the United States and South Africa must provide ironclad assurances of the Angolan regime's security from external and internal threats before Cuban troops can be sent home.

Rodrigues, who is also known as Kito, has been involved in several rounds of direct talks with U.S. and South African officials, although Angola does not have diplomatic relations with either country. He last met with Deputy Assistant Secretary of State Frank Wisner in Paris March 13.

The Angolan side reportedly asked to continue the talks in Washington, evidently because of a desire for direct access to the top levels of the U.S. government.

According to informed sources, there was an understanding that Rodrigues would come to Washington only if he could bring new decisions by Angola that would enhance the prospects for agreement. Although Rodrigues left Luanda April 6, just six days after an unusual meeting of the Politburo and Central Committee of the Marxist ruling party, there was no indication that he brought a decision to send the Cubans packing or otherwise resolve the situation.

The fact, however, that a top-ranking Angolan official was received at the White House in confidential talks is likely to generate widespread speculation and renewed hope for a breakthrough in the marathon maneuvering about Namibia and Angola.