The thermal regime is especially critical at short-line fault interruption (see Section 3). The
circuit parameters directly affecting this regime are the rate of decrease of the current to be interrupted (di/dt) and the initial rate of rise of the transient recovery voltage (du/dt) immediately after current zero. The higher the values of either of these
two parameters, the more severe the interruption. A high value of di/dtresults in a
hot arc with a large amount of stored energy at current zero, which makes interruption more difficult. High values of du/dtwill result in an increase of the energy to the
post-arc current