The Development of the Current Limiting Protector (CLP)

The development, the theory and the testing of the "Current Limiting Protector" (CLP) and a compatible current level sensing and trigger circuit are described. The CLP consists of a current carrying main conductor and a parallel fuse. In response to a short circuit, a series of gaps are formed in the main path by pyrotechnic cutting. The gap arc voltages commutate the current to the parallel fusible element, which then interrupts the current in a current limiting mode. High power tests in 4 to 15 kV circuits limited prospective short circuit currents of 40 kA (rms) to less than l5kA. The CLP offers single shot current limiting protection with low let-through i2t.