Applying current-limiting fuses to improve power quality and safety

Abstract

This paper describes power quality and safety The distribution fault currents on the Florida system are higher benefits that can be achieved by applying current-limiting than those on the Carolina Power and Light system. Fault fuses (CLFs) instead of expulsion fuses. CLFs can improve current level is very important when determining how well power quality by reducing voltage dip magnitude and duration CLFs will support system voltage under fault conditions. If during faults. Safety is improved because CLFs reduce the the fault current is too low, a CLF may not operate in the risk of fire and injury by eliminating the flame, violence, and current limiting mode and instead wait for a current zero to noise associated with expulsion fuse operation. This paper clear a fault, which is how an expulsion fuse operates. compares expulsion and CLF fuse operations using Alternative Transient Program (ATP) simulations, laboratory tests, and 11. FUSE OPERATION THEORY EXPULSION FUSES are zero-awaiting devices which wait Power and Light (cp&L) for the current through the fuse to pass through zero before extinguishing the contained arc and clearing the circuit (Fig. field experiences. The proper application of CLFs to improve power On the system and other relevant field experiences are described.

Modeling Protective Devices for Distribution Systems With Distributed Generation Using an Emtp-Type Tool

“…Upon interruption, the operation of a current limiting fuse results in the insertion of additional impedance and the development of an arc voltage; when this voltage exceeds the system voltage, the arc is extinguished and the action is accomplished [18]. An expulsion fuse heats to its melting point when the fault occurs; the current continues to flow in the form of an arc, at zero current the arc is extinguished, being the fuse subjected to a transient recovery voltage (TRV), whose frequency and magnitude depend on the operating conditions [24]. One or several arc reignitions can be caused by the TRV; the process stops only when the dielectric strength build up is faster than that caused by the TRV.…”

Optimal design of a medium voltage hybrid fault current limiter

“…Other solutions, including the superconducting FCL [4] and resonant circuits [5], only limit the fault current while the existing CB takes care of the current interruption. The solutions used today in distribution systems are based on the current limiting fuse [6]. The fuse is both simple and cheap, but has to be replaced after each use.…”

Current-limiting fuses improve power quality

“…This arc voltage supports the system voltage. Significant improvement in power quality is achieved when fault currents are high (strong source) because CLFs operate in their current-limiting mode with very short voltage dip durations [3,4]. If fault currents are small (weak source), CLFs will wait until a current zero to operate like expulsion fuses.…”