PCIR-01 High Voltage Cable Fault Protection device (SCADA compatible)rnrn
Operation principle of PCIR-01 is based on the measurement of earth leakage current in case of connection to high precision phase line of the low-noise continuous reference voltage source. This low-noise high precision voltage source is connected to phase line through the chain of high-stable precision resistors. Earth leakage current is being registered on the resistor with known resistance by means of precision instrumental amplifier. Rated parameters of the resistor and amplification factor are set in a following way: – signal on the output of instrumental amplifier at the detection of leakage current through the insulation resistance of 360 kOhm which is in the middle of the range of the output voltages of instrumental amplifier. The level of operational control of 360 kOhm is defined by the scheme and thus is constant for each Control and Operation Unit.;  deviation range of the noise signal in the measured circuit doesn’t exceed half of the dynamic range of the instrumental amplifier. One of the four output signals of the instrumental amplifier is commutated through signal relay to input of the DC current amplifier, then it’s filtered to get rid of the noises and being amplified and transformed to the level of analog-digital converter of the micro-controller. Micro-controller in its turn performs the analysis of this input signal. Basing the comparison of measured results with controlled level the corresponding indication is displayed on the front panel and output relays change the position of the contacts to allow operation or open the contacts of the main high voltage switch.