Siemens introduces Fusesaver™—the world’s fastest medium-voltage outdoor vacuum circuit breaker

Wendell, NC | Jan 30, 2014

Siemens Low and Medium Voltage division today introduced Fusesaver, an extra-high-speed interrupting device for use on fuse protected tap lines in electrical utilities with overhead distribution systems. Upon sensing a fault current, Fusesaver can detect, open and clear a fault in as little as one half-cycle, interrupting at the first current zero after the vacuum interrupter contacts separate. Thus, interrupting time is one cycle or shorter, less time than it takes for the fuse to melt during a moderate fault condition. Preventing fuses from blowing during temporary fault situations using this technology can save utilities thousands of dollars per year.

“Improving power quality in a demanding and competitive business environment is one of the most challenging tasks for power utilities today,” says John Karczmarczk, vice president and general manager, Medium Voltage and Systems, Siemens Low and Medium Voltage division. “Reducing the number and duration of power outages and limiting the number of affected customers are important steps toward this goal.”


Eighty percent of electrical short circuits on feeder lines that cause the fuse cutout to operate are only temporary. Each time a fuse cutout operates, utility customers remain without power until the utility determines there is a power outage, dispatches a service crew to locate the fault, identify and repair the cause and reset the fuse cutout. This often takes hours, leading to high repair crew costs and unhappy customers.


Fusesaver is extremely light—only 12 pounds—and is connected in series with the fuse. It is self-powered from line current and can be mounted on the line, on the pole or on the crossbar. The device also collects and stores historical data related to its operation, helping the operator understand the frequency and nature of the faults, whether temporary or permanent. Opening and closing of the Fusesaver can be initiated manually using a hot stick, remotely using a laptop PC or with the remote control unit (RCU) through the utility’s SCADA system. Furthermore, installation of the Fusesaver in the distribution system does not require any changes to the utility’s existing overall protection scheme. Fusesaver can be configured for the particular installation by the user, reducing the number of spare units that need to be held in inventory.


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