In this manuscript is showed existing situation in electrical system of electrical transport in city Riga. In the manuscript the imperfection of existing electrical network is determinated and new solution with new bidirectional power flow regulator is offered for prevention of' imperfection. In the manuscript the main problems are inspected what have to be solved to get new regulator, what will be able to regulate the power flow from AC network to DC network according the circumstances determinated by connected load to the network. In this case — tram cars. In the manuscript the results of computer model of power existing system and explanations of it are reflected.