Except when federal funds are available for the payment of direct financial assistance to persons displaced by the acquisition of their real property, in all condemnation proceedings for the taking or damaging of real property under the exercise of the power of eminent domain, the condemning authority shall pay to displaced persons reimbursement for their reasonable relocation costs, determined in the same manner as under the federal Uniform Relocation Assistance and Real Property Acquisition Policies Act of 1970, as amended from time to time, and as implemented by regulations promulgated under that Act. This Section does not apply to the acquisition or damaging of property under the O’Hare Modernization Act.