April 18 (Reuters) - Bentley Systems, an engineering software company with a market value of about $15 billion, is exploring options that include a sale after attracting acquisition interest, according to people familiar with the matter.

Among the companies that have expressed interest in a deal with Bentley are electrical equipment maker Schneider Electric and design software firm Cadence Design Systems , one of the sources said.

The Bentley family controls the eponymous company through a special class of shares. The company has formed a special committee of its board of directors to explore its options, that include an outright sale of the company as well as a joint venture, the sources said.

The sources requested anonymity because the discussions are confidential and cautioned that no deal is certain.

Bentley Systems, Schneider Electric and Cadence did not immediately respond to requests for comment. (Reporting by Milana Vinn and Anirban Sen in New York Additional reporting by David Carnevali; Editing by Lisa Shumaker)