Seattle-based InfrastruX Group Inc., which builds and maintains electric and gas transmission and distribution systems, has filed with the Securities and Exchange Commission to issue an initial public offering to raise up to $290 million in cash to pay down debt and fund possible acquisitions. The company serves about 650 electric and gas utilities, including Dallas-based Oncor and Columbus, Ohio-based American Electric Power. InfrastruX operates in the Southwest, Midwest and Northeast. In its prospectus, filed on Aug. 10, the company says its work is increasing because of a focus on renewable energy and would benefit from potential national renewable portfolio standards and cap-and-trade legislation being debated in Congress. Such laws would require the development of more transmission lines. The company says it has a backlog of $403 million. Last year it reported a loss of $36.57 million on revenue of $827 million. Tenaska Power Fund LP, Omaha, a private equity firm, purchased InfrastruX from Puget Sound Energy, Bellevue, Wash., for $275 million in 2006. InfrastruX has not set a price for the company’s shares, nor has it indicated the timing of the offering.