Due to the high amount of installed devices on the Hungarian medium voltage grid it is important to be aware of the exact causes of malfunctions. If the causes are know it is possible to prevent the undesired malfunctions, therefore the operational safety can be increased. There are continuous investigations performed in the High Voltage Laboratory of BUTE to find out the causes of malfunctions, which were previously determined unknown by distribution system operators.
The medium voltage fuse is the most frequently malfunctioning device on the medium voltage network. Moreover the causes of its malfunctions are also unknown in the highest ratio. This might mean that in many cases they operate due to electrically gratuitous reasons. I had an opportunity to join the experiments, which can be divided into two categories. Electrical and Thermal Aging tests.
The precise diagnostics of metal oxide surge arresters is important as their reliable operation is crucial in terms of operational safety. There are already developed and well-tried methods, but there it is still a hard task to forecast the lifetime and durability of these devices. That is why a new approach was made in the HVL of BUTE, where the main point is to examine the durability of an arrester not only the change in its characteristics.