To use distribution networks effectively and ensure the smooth introduction of distributed generations, a loop or mesh structure for distribution systems has been proposed using back to back type loop power flow controller (LPC) by CRIEPI. The installation space of looping equipment is restricted in power distribution systems. It is necessary to miniaturize the equipment. We developed 6.6kV-1MVA transformerless loop balance controller (LBC) as one approach to miniaturization of LPC. A development of LBC has been entrusted by a national project: "Demonstrative Project on Power Network Technology" from the New Energy and Industrial Technology Development Organization (NEDO).