The Roman Catholic Church today named a 52-year-old expert in canon law, Archbishop Jozef Glemp, to succeed the late Cardinal Stefan Wyszynski in the powerful office of primate of Poland. l

A longtime private secretary of Wyszynski, Archbishop Glemp is thus poised to become one of the main actors in the Polish drama, along with the leader of the Solidarity trade union federation, Lech Walesa, and the Communist Party chief, Stanislaw Kania. By virtue of his office as archbishop of Warsaw and Gniezno and 56th primate of Poland, he will be looked on as the nation's spiritual leader.

His nomination was announced simultaneously in Warsaw and at the Vatican. As if to underline the stormy conditions Archbishop Glemp is likely to face, the announcement coincided with signs of renewed labor unrest in Poland, with dockworkers in northern Baltic ports threatening a one-hour strike for Wednesday, and employes of the national airline, Lot, planning a four-hour "warning strike" for Thursday.

Church sources here said they expect Archbishop Glemp to continue Cardinal Wyszynski's policies toward the communist authorities and Solidarity. The former primate strongly supported the workers in their struggle, but also urged moderation in dealings with the state.

A short, jovial man, Glemp told a radio interviewer shortly after his nomination was announced that he would attempt to follow in Wyszynski's footsteps. He said that at a time of great tension in Poland, the church should remain a voice of reason and calm.

The archbishop led a group of Polish pilgrims to the Vatican last week and held private talks with the pope. The son of a salt miner, was born in the Gniezno diocese, the oldest in Poland, and was ordained in 1956. He studied canon law in Rome, where he received a doctorate.

Archbishop Glemp lacks his predecessor's charisma and authority. But he is regarded by his associates as more open and approachable. He was described by the Rev. Alojzy Orszulik, the church spokesman, as Cardinal Wyszynski's personal choice as a successor.

As Wyszynski's private secretary for 12 years, Glemp gained considerable experience in negotiating with the state. During his two years as bishop of Olsztyn, he also earned a reputation as an able administrator and diplomat in defusing local disputes.

"He has an insider's knowledge of church-state relations. He is a very precise, but also very sensitive," Father Orszulik commented.

It is expected that Archbishop Glemp will be named a cardinal shortly by Pope John Paul. He also is likely to assume Cardinal Wyszynski's role as chairman of the Polish Episcopate.

The strike calls in the ports and at the airline came at a bad time for Poland's communist leaders, who are preparing for an extraordinary Communist Party congress scheduled to open next Tuesday. They had been hoping for a period of labor peace to convince the Kremlin that Poland has found a measure of political and social stability.

The church also had urged a halt to strikes to allow the government a breathing space and as a mark of respect for Wyszynski, who died May 28.

Although both threatened strikes involve essentially local issues, the dispute at Lot could set important precedents. Lot's 6,000 employes are claiming the right to elect their own director rather than accepting the choice of the Ministry of Transportation -- or, as local Solidarity activists put it, "having someone brought to us in a briefcase."

The Polish National Assembly is debating a new law allowing for self-government in state enterprises. There is still some doubt whether the final version will allow employes to elect the director or whether they will only have consultation rights.

Under traditional communist practice, important economic decisions are taken by the central planning apparatus and implemented through the bureaucracy. This highly centralized system is in the process of being dismantled in Poland, but there is still considerable disagreement over how far the devolution in decision-making should go.

Solidarity favors giving workers' councils full autonomy. There is, however, strong resistance to this idea from government bureaucrats, many of whom face the prospect of losing their jobs if the economic reform is taken to its logical conclusion.

The dispute at Lot goes back several months, to when the former director retired and a new one had to be appointed. Airline workers had already formed their own workers' self-government conference and insisted that they had the right to choose the new director. After a secret ballot, they elected the present deputy head of the commercial department, Bronislaw Klimaszewski, as the new director.

The choice was rejected by the Ministry of Transportation, which proposed the names of two Air Force generals instead. Dissatisfied by the stalemate, Lot personnel voted to stage a warning strike Thursday with the threat of an indefinite general strike July 24 unless the dispute is resolved.

Thursday's strike, from 8 a.m. until noon, will also affect foreign planes flying in or out of Polish airports.

At a press conference today, a Solidarity spokesman at Lot said the union realizes that the strike comes at a difficult time, but it is unconnected with next week's party congress. Lot employes merely want the airline to be run efficiently, he said, and are not striking for political reasons.

"Under the old system, the ministry would decide everything -- from opening a new station, to who went abroad as a representative, to whether we could give a business lunch. They have to be made to realize that this is the 20th century," said Maciej Kwatkowski, who also works in the airline's public relations department.