reasons. There are also some faults caused by human factors such as sub-standard installation, improper maintenance.
With the rapid development of the grid, the system short- circuit current is increasing. And with the frequently occur of extreme weather, the running environment of devices will become bad. So, the current transformer has become one of the devices which have a high failure rate in power system.
According to the operating conditions, it can be found that, the multi-oil CT in the longer run of years, there will be varying degrees of leakage of oil and fuel tank, the second terminal junction box severe corrosion; oil laboratory test cycle according to the power transmission overhaul state regulations require and the corresponding high-pressure test, a lot of oil CT and especially less oil CT many times to take the oil to take the damage to the port or low oil level defects. By SF6 CT running show of its excellent performance, with the exception of the test cycle power transmission overhaul state regulations require decomposition of matter and micro-water test without the need for other tests, almost no leakage or corrosion phenomenon; but the part of the SF6 CT silicone rubber coat cracking phenomenon due to formulation problems, part of the CT secondary terminal box can also occur after long-running moisture.