APTP Articles

Amplifying Network Reliability: Seamless Transition from Lateral Fuses to Auto-Reclosing, Line-Mounted Circuit Breakers

The Siemens Fusesaver is a trailblazing solution in circuit protection: a compact, cost-effective, single-phase auto-reclosing circuit breaker specifically engineered to mitigate the impact of frequently encountered temporary faults in lateral and spur overhead networks.

Self-powered with an auxiliary backup supply, Fusesaver is a cornerstone of technological innovation, integrating microprocessor-controlled protection functions and wireless connectivity. It facilitates multi-phase protection functions and synchronous ganged switching operations, redefining the potential for network reliability. These qualities position the Fusesaver as the optimal asset for augmenting network sites formerly protected with Cut Out or Expulsion Drop Out Fuses (EDO) and Master Drop Out Fuses (MDO).

Features for Enhanced Protection and Network Reliability

The recent advancements to Fusesaver render protection grading, network reliability improvement, and operator safety enhancement more straightforward and effective than ever. The integration of hydraulic recloser curves and Inverse Definite Minimum Time (IDMT) current curves, coupled with traditional i2t fuse curves, offers an unprecedented cost effective means to ensure reliable grading with upstream protection at lateral and spur network sites.

More Than a Fuse-Saving Device

Originally designed to function in tandem with a partner fuse to clear transient or temporary faults without fuse operation, Fusesaver has substantially improved network reliability. But the industry’s push for enhanced functionality and heightened operator safety has led to a transformation; the Fusesaver auto-reclosing circuit breakers now allow for the complete removal of partner fuses.

Fusesaver closes directly on load using vacuum technology (safe and recommended practice)

Minimising Customer Impact and Enhancing Operator Safety

Implementing a trustworthy circuit breaker underpinned by a reliable auxiliary backup supply enables the protection of a larger number of network sections, significantly mitigating the number of customers impacted by faults. Moreover, Fusesaver now incorporates cold load pickup and inrush restraint configurable parameters to prevent unnecessary tripping when closing the circuit breaker after extended outages.

The Fusesaver’s battery-powered auxiliary backup supply ensures a seamless and reliable operation, upholding operator safety by ensuring that protection is always activated and ready to operate without any wake-up time. It allows operators to safely close the auto-reclosing circuit breakers onsite, utilising the vacuum interrupter.

The Fusesaver circuit breaker, supported by a robust auxiliary backup supply, nullifies the need for an operator to close an open link, fuse link, or any other device to an open contact in the air. Synchronous ganged operation further bolsters safety when closing, ensuring protection is always engaged, whether the operator is closing onto an existing or new fault condition.

By Steven Pell, Product Portfolio Manager, Siemens