Smithsonian Secretary S. Dillon Ripley has had an elaborate security system installed in his office to protect himself against violence and to guard against leaks to the news media and the General Accounting Office, which is now auditing the Smithsonian at the request of Congress, according to well placed sources.

Last fall, according to sources within the Smithsonian's Office of Protection Services, Ripley ordered approximately $8,000 worth of security devices for his office in the Castle Building on the Mall. Other security devices were ordered for the offices of T. Ames Wheeler, treasurer of the Smithsonian, these sources said.

The new security system was installed in two stages, part last July and part last January. Among the devices now in place to protect Ripley's second floor office are:

A closed circuit television system that is hooked up each evening when Ripley leaves his office. A camera is placed on an antique chair outside Ripley's door and a reception set is placed on a guard's desk at the east entrance to the Castle Building. A security guard is supposed to watch the monitor through the night to guard against break ins.

Hidden sensors were placed in molding around the door inside Ripley's large office suite. The sensors are activated at the end of the day and are apparently connected to an alarm in the Office of Protection Services, located in the nearby Arts and Industries Building.

A "kick-bar" under Ripley's desk. This device allows Ripley to call secretly for help should someone threaten him while he is at work.

Carl W. Larsen, director of the Smithsonian's public information office, was asked yesterday to explain why Ripley felt it necessary to have this new security system installed. Larsen was also asked whether the new devices cost $8,000, as sources told The Washington Post.

"The Smithsonian Institution does not discuss any aspect of its security system," Larsen replied in writing. "To do so would weaken the ability of such systems to provide the intended security.

Although the new security devices were installed only three months ago, Ripley has in recent weeks ordered additional cameras for his office, according to sources. These cameras and related equipment will cost about $4,000, the sources said.

Ripley also reportedly tried to change the combination on his office safe recently. He asked for instructions on how to do it himself so that no one else would know the combination, according to one source.

But the Smithsonian secretary botched the job and the Mosler Safe Co. had to be called in to repair the broken combination lock, the source said.

Sources said there are a number of reasons for Ripley's heightened concern for his personal safety and security within his office.

The kick bar was installed last summer under Ripley's desk following an incident at the Smithsonian's Silver Hill storage facility, according to these sources. A supervisor there was allegedly bludgenoed to death by one of his employees. More recently, On Feb. 20, a guard at the Air and Space Museum was shot and killed, allegedly by another guard while both were on duty.

Sources said the hidden sensors and closed circuit television system were installed last January because Ripley became concerned about employees providing embarassing information to GAO auditors and to reporters for both The Washington Post and The Federal Times concerning the Smithsonian.

The Senate Appropriations Subcommittee on the Interior and Related Agencies, which handles the Smithsonian's $100 million a year federal appropriation, ordered the GAO audit last summer after senators on the subcommittee became concerned about the Smithsonian's financial practices.

The audit report from the GAO is expected to be ready this week, according to the subcommittee staff. Senate hearings on the Smithsonian's 1978 budget request are scheduled for March 24.

Smithsonian employees have been covertly providing embarrasing information to the GAO, the subcommittee (which then transmits information to the GAO to be looked into) and the news media. Top Smithsonian officials have attempted to figure out where the leaks are coming from, according to several sources. The closed circuit television system and the sensors were put into Ripley's office to guard against papers being taken from his files and then leaked, one source said.

After each article in The Washington Post about some aspect of the Smithsonian's activities, top officials meet to try to determine how The Post received its initial information.

Yesterday, for example, Ripley met with top officials in the Office of Protection Services because an article in Tuesday's editions of The Post mentection Services because an article in fice was often carried out through an "old boy" network of retired military officials who hired their friends for top positions.

At yesterday's meeting, which sources said became quite heated, one security official was overhead saying "we can justify that," meaning the hiring practices.