HVTest HTFZ-III, Руководство пользователя

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7
I 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.
Figure 1 (b) shows circuit diagram of JS-8 type operating cycles counter, it
is rectifier type structure. When the arrester operating, voltage drop on the valve
R1 charge capacitor C through full-wave rectifier, then C discharge to L of
electromagnetic counter and let it count. For this counter, the resistance value
of valve R1 is small (when at 10kA, the voltage drop is 1.1kV), current capacity
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