OBLUM ELECTRICAL INDUSTRIES PRIVATE LIMITED SURGE MONITOR SURGE
OBLUM ELECTRICAL INDUSTRIES PRIVATE LIMITED SURGE MONITOR
SURGE MONITOR 1. TERMINAL 2. EARTHING & MOUNTING BRACKET 3. VIEWING WINDOW GENERAL : Surge Monitor Consists of a discharge counter to count the surge discharges through the arrester and a milli-ammeter to monitor the leakage current. Regular monitoring of the Surges through this device helps to understand the frequency of surges that occur in the system.
SURGE MONITOR GENERAL : Surge Monitor Consists of a discharge counter to count the surge discharges through the arrester and a milliammeter to monitor the leakage current. Regular monitoring of the Surges through this device helps to understand the frequency of surges that occur in the system.
SURGE MONITOR CONSTRUCTION: Oblum Surge Monitor houses a pulse counter and an ammeter associated with bypass zener diodes. The viewing polycarbonate window is sealed in place by silicone rubber adhesive and bolted.
SURGE MONITOR 4. BRIDGE RECTIFIER 5. Zn. O ELEMENT 6. MILLI AMMETER 7. DISCHARGE CAPACITOR 8. . ELECTROMAGNETIC COUNTER OPERATION: The milli Ammeter shows the leakage current through the arrester in the normal conditions of operation. The leakage current drawn is a measure of soundness (healthiness) of the Surge Arrester. The leakage current in the red band between 2 m. A to 5 m. A of the meter indicates the deterioration of the metal oxide elements. Contd. . . 2
SURGE MONITOR OPERATION: The qualitative information regarding the arrester health, obtained from the milli-ammeter, helps the user to take preventive measures before the arrester failure. The leakage current obtained through the permanently connected monitor is usually the total current that constitutes capacitive current, resistive current and insulator surface leakage current. Hence, the data obtained in these devices need a critical analysis before taking any decision / action regarding the arrester. It is important to note that the measured leakage current data, obtained during the arrester service, needs to be compared with the data obtained during initial commissioning. In order to evaluate the leakage current ambiguously, it is essential that the operating voltage and the ambient conditions are recorded during the measurement of the resistive current. Contd. . 3
SURGE MONITOR OPERATION: Cleaning of the arrester housing is necessary, if the housing is contaminated, before taking the readings as the surge monitor reads the leakage current of the arrester housing as well as the metal oxide elements. SURGE ARRESTERS ARE CONNECTED IN PARALLEL WITH THE EQUIPMENT TO BE PROTECTED TO DIVERT THE SURGES
TESTS ON SURGE MONITOR The Surge Counter is designed and tested to operate at impulse currents as low as 100 Apms to as high as 100, 000 Amps. The ammeter, counter and the rest of the circuit is housed in a sealed container. The Monitor needs no auxiliary supply. Seal Leak Test is performed on the Surge Monitor to check hermetical sealing. The voltage across the Surge Monitor terminal does not exceed 10 V r. m. s. during normal conditions.
SURGE MONITOR Reliability: The Surge Monitor line terminal is solidly connected to the ground terminal of the surge monitor through an inbuilt metal oxide element satisfying the operational requirements. Mountiing: The Surge Arrester is mounted on an Insulating Base and Surge Monitor is connected in series with the Arrester. Connecting lead between surge arrester and surge monitor is insulated. The Surge Monitor is to be fixed at a height of 1. 5 meters from the ground level for better viewing of the meter.
MAINTENANCE Surge Monitor needs no maintenance. In case the Surge Monitor is removed and sent for repair at the manufacturer's works, the connecting lead from the Arrester is to be positively earthed. The earth terminal of the Arrester should never be isolated. THE ARRESTER ACTS AS A NEAR INSULATOR PRIOR TO REACHING BREAKDOWN OR THRESHOLD VOLTAGE AND ACTS AS A CONDUCTOR THEREAFTER.
- Slides: 10