7
充电指示：
Charging indicator
III Impulse test
1. Test principle
Figure 1 is circuit diagram of JS-type operating cycles counter. Figure 1 (a)
shows circuit diagram of JS-type operating cycles counter, also called
dual-valve plate structure. When the arrester operating, the discharge current
drop voltage through the valve R1, and charge capacitor C through the valve
R2, then C discharge to the inductance coil L of magnetic counter, let it rotate a
division and record one time. Changing the resistance values of R1 and R2, the
counter will have different sensitivity. Generally the minimum action current is
100A (8/20μs) impact current. Because there is some voltage drop on R1, and
these will increase residual voltage of arrester, the instrument is mainly used for
HV arresters above 40kV.
Fig 1 Circuit diagram for JS-type operating cycles counter
(a) JS-type
(b) JS-8 type
R1, R2-nonlinear resistance
C-Energy-storage capacitor
L-Counter coil
D
1-4
A silicon diode
