It is important to regularly check for contamination on the surface of the porcelain sleeve of the arrester during daily operation. When the porcelain sleeve becomes heavily polluted, the voltage distribution becomes uneven and can lead to issues. In arrester models with parallel shunt resistances, an increase in voltage distribution in one component can cause a significant rise in current through its parallel resistance. This can result in the burning out of the parallel resistance, leading to faults and potential damage. Furthermore, it can also impact the arrester's ability to extinguish arcs. Therefore, timely cleaning is necessary if the surface of the arrester porcelain sleeve is seriously dirty.
To ensure the proper functioning of the arrester, it is important to conduct frequent inspections. One should inspect the lead and grounding lead of the arrester for any burn marks and broken strands. Additionally, it is crucial to check for invisible defects by examining the discharge recorder. It is also important to verify that the upper lead of the arrester is well sealed to prevent water ingress, which can lead to accidents. To achieve this, one should check the tightness of the cement joint between the porcelain sleeve and the flange. Moreover, a waterproof cover should be installed on the lead wire of the 10kV valve arrester to prevent rainwater infiltration. Another key aspect to consider is whether the arrester is positioned close enough to the protected electrical equipment and whether there is sufficient electrical distancing between the two. After a thunderstorm, it is advisable to verify the operation of the recorder. Another crucial point to consider is checking the leakage current and repairing it if the power frequency discharge voltage is above or below standard levels. If the discharge recorder operates too many times, an overhaul is necessary. Finally, if the porcelain sleeve and cement joints are cracked, or the flange and rubber pads fall off, immediate maintenance is crucial.
Regular checks on the arrester's insulation resistance are important to maintain its proper functioning. A specialized 2500-volt insulation shaker is used to measure the insulation resistance, which is then compared with the previous results to detect any variations. If no significant changes are observed, the arrester can be put back into operation. However, when a significant drop in insulation resistance occurs, it's usually due to poor sealing that results in moisture or spark gap short circuit. In such cases, a characteristic test should be conducted, and if the insulation resistance is found to be lower than the qualified value, necessary measures should be taken to restore its proper functionality.
On the other hand, a significant rise in insulation resistance is typically a result of poor internal contact, breakage of the internal parallel resistance, or spring relaxation and internal component separation. These issues must also be addressed immediately to avoid any further complications and ensure the arrester's smooth functioning. Therefore, regular checks, proper maintenance, and timely repairs are vital to maintaining the arrester's efficiency and reliability.
To catch the potential faults lurking within the valve arrester, it is advisable to conduct a preventative test prior to the arrival of the thunderstorm season on an annual basis.