La leakage current analyser test. surge arrester leakage current test. la testing.

#surge arrester leakage current test.
#leakage current analyser test
#lightning arrester leakage current test
#la scope test
#electrical equipment testing
hight voltage la leakage current test
#This meter continuously measures and displays the leakage current flowing through LA, and counts the number of surges experienced by LA. Then why do we need to measure leakage current separately? The meter installed, measures the total leakage current through LA. But this total leakage current is a vector sum of the capacitive and the resistive current through LA. And to know the healthiness of LA accurately, we need to check the resistive component (Ir) of the total leakage current (It).
The size and number of ZnO elements for a particular LA are decided based on the rating and design of that LA. The healthiness of LA is nothing but the intactness of the insulation property of these ZnO blocks. Hence, to measure the insulation level of these ZnO blocks accurately, we need to measure resistive leakage current (Ir), through these blocks, and not the total leakage current (It).
Now to understand this further, we represent, LA with a circuit diagram also called an equivalent circuit diagram. The top-end, line terminal of the LA is connected to a High voltage line. And LA ground terminal is connected to the earth. We can see both Capacitive Current (Ic) and resistive current (Ir). Adding to total leakage current (It). As in the phasor diagram, resistive leakage current (Ir) is in phase with applied LA terminal voltage (V). Capacitive current (Ic) leads (Ir) by 90 degrees. Capacitive current (Ic) is large as compared to (Ir), & practically (Ic) remains constant. Whereas, resistive leakage current (Ir) increases over time, due to lightning impulse, fault, aging, moisture ingress, or insulation failure of Surge Arrester. Resultant leakage current (It) is the vector sum of (Ir) & (Ic). The magnitude of total leakage current (It) is equal to the square root of the addition of squares of (Ir) & (Ic).