A type of surge protection device consists of two main sphere electrodes S1 and S2 connected to the line and the arrester respectively. An auxiliary needle electrode is placed midway between the centers of these two spheres. Which type of lightning arrester is this?

In a power system protection scheme, the property that allows a relay to differentiate between a fault occurring within its own protected zone and a fault occurring elsewhere is known as:

Given the following statements: Assertion (A): Overcurrent protection is generally not used as the primary protection for alternators. Reason (R): Alternators have large short-circuit currents that can be sustained for long durations without damage. Which of the following is correct?