Negotiations between Prince George's County and the union that represents 800 county police officers fell apart yesterday after 11 months of behind-the-scenes efforts to agree on a contract.

Police union president Larry Hester blamed the collapse of the negotiations on county executive Lawrence J. Hogan, who he said was willing to sacrifice the security of county police officers to save a few dollars.

"Every time we add up the figures, we come up with a loss," Hester said. "Mr. Hogan and his negotiators are constantly changing their mind" [on previously agreed-upon items]. He said the union will ask the county's Public Employes Relations Board to declare the talks at an impasse, and intercede in the contract dispute.

"We have tried to be very low-key about this throughout the negotiations," Hester said, "Given the choice between compromise and conflict, we chose compromise. [But] given a choice between conflict and capitulation, we choose conflict."

A county official said yesterday that the county and the union had been unable to agree on a "total monetary package including retirement, educational benefits, salary and clothing allowance. The issue is how much money in total the county can afford."

The impasse with the Fraternal Order of Police is the fourth such contract dispute this year between Hogan and a county union. The unions have repeatedly argued that Hogan has been looking for a dispute to win political points and does not understand the principles of collective bargaining.

In the most publicized of these disputes, Hogan has spent the last half-year embroiled in court battles with the county's 1,500-member public employes union, which has threatened to strike on numerous occasions since negotiations for a new contract collapsed in February.

Hogan, however, has tried to avoid a public conflict with the police union because of the largely negative political impact such disputes have had on previous county executives.

A police slowdown in mid-1978 is widely believed to have been the final blow to the reelection efforts of then-county Executive Winfield M. Kelly in his race with Hogan.

While neither side sees the dispute as being that serious, Hester said that the union felt that nothing could be gained by returning to the bargaining table.

In addition to the safety issues, Hester said his union and the county could not agree on wages, educational benefits and union security issues.

Although Hester said he is now asking for the county's public employes board to get involved in the dispute, his union is more interested in having Hogan agree to implement a controversial campaign promise he made to support binding arbitration in contract disputes with public safety employes.