What it's not: Stacks of frozen jellyfish.

What it is: A HVDC valve including two stacks of serially connected insulated gate bipolar transistors (IGBTs), used for converting DC voltage to AC voltage or vice versa using pulse width modulation (PWM) technology. The valves are a component of HVDC Light technology, developed by ABB, and are designed to transmit electric power long distances underground or under the sea. Voltage source converters change the signal from AC to DC voltage to transmit and then back to AC voltage for output. The metal rings seen in this photo are cooling elements for the stacks of circuitry.

According to ABB, HVDC Light systems can handle power transmission of 50 MW to 1,000 MW. Its voltage source converters — purportedly 25% smaller than conventional HVDC converters — are designed to block cascading trips that occur in AC systems and reduce downtime after outages with their “black start” capability. Thankfully, no jellyfish were harmed for the purpose of this photograph.