A modular interconnection device, comprising: a modular port assembly configured to transmit alternating current and/or direct current; a node coupled to an AC source via a first switch and the modular port assembly, the first switch being configured to selectively disconnect the modular interconnection device from the AC source; a converter coupled to the node via a second switch and coupled to a DC source via a third switch, the converter configured to convert the AC current into DC current or convert DC current into AC current; characterized in that the modular interconnection device further comprises a local controller coupled to the first, second and third switches and configured to control operation of the first, second and third switches, wherein the modular port assembly comprises: a first port coupled to the first switch and configured to receive the AC current from the AC source or transmit AC current to the AC source; a second port coupled to the node directly or via a fourth switch, and configured to selectively transmit the AC current between modular interconnection devices; a third port coupled to the third switch and configured to selectively transmit the DC current between the modular interconnection devices; and a fourth port coupled to the node and configured to transmit the AC current between the modular interconnection devices. a modular port assembly configured to transmit alternating current and/or direct current; a node coupled to an AC source via a first switch and the modular port assembly, the first switch being configured to selectively disconnect the modular interconnection device from the AC source; a converter coupled to the node via a second switch and coupled to a DC source via a third switch, the converter configured to convert the AC current into DC current or convert DC current into AC current; characterized in that the modular interconnection device further comprises a local controller coupled to the first, second and third switches and configured to control operation of the first, second and third switches, wherein the modular port assembly comprises: a first port coupled to the first switch and configured to receive the AC current from the AC source or transmit AC current to the AC source; a second port coupled to the node directly or via a fourth switch, and configured to selectively transmit the AC current between modular interconnection devices; a third port coupled to the third switch and configured to selectively transmit the DC current between the modular interconnection devices; and a fourth port coupled to the node and configured to transmit the AC current between the modular interconnection devices. a first port coupled to the first switch and configured to receive the AC current from the AC source or transmit AC current to the AC source; a second port coupled to the node directly or via a fourth switch, and configured to selectively transmit the AC current between modular interconnection devices; a third port coupled to the third switch and configured to selectively transmit the DC current between the modular interconnection devices; and a fourth port coupled to the node and configured to transmit the AC current between the modular interconnection devices.