Finally , we further research some problems which appear in the economic evaluation of urban power network renovation , that is , how to determine and calculate the discount rate , the internal rate of return ( irr ) , the profit from urban power network renovation and the rising of electricity price , are presented 本文最后一部分較深入的研究了城網(wǎng)改造經(jīng)濟(jì)評(píng)價(jià)中遇到的一些問題,即如何確定和計(jì)算折現(xiàn)率及內(nèi)部收益率( irr ) 、城網(wǎng)改造收益和電價(jià)加價(jià)等。