Back to back

An HVDC Light® back-to-back station consists of two converters located in the same building. 

An HVDC back-to-back station can be used to create an asynchronous interconnection between two AC networks. There are several back-to-back stations in operation in the world. In these installations both the rectifier and the inverter are located in the same station and are normally used in order to create an asynchronous interconnection between two AC networks, which could have the same or different frequencies. Another benefit is using a back-to-back for splitting up a too strong network to reduce short circuit current. 

The direct voltage level can be selected without consideration of the optimum values for an overhead line and a cable and is therefore normally quite low, 150 kilovolts (kV) or lower. The only major equipment on the DC side is a smoothing reactor.