Performance of a temperature rise test on a 420kV pantograph disconnector

Damstra Laboratory is specialized in validation of the performance of components and systems used in the distribution, security and control of electrical power. In this field of expertise Damstra Laboratory is capable to perform tests to a large variety of products. Every now and then we get a request that requires some additional planning and alignment with the customer to make sure the test set up fits the dimensions of test area so required conditions for valid test ratings can be met.

End of 2017 Hapam B.V. from the Netherlands requested a temperature rise test on a pantograph disconnector in accordance with IEC62271-102. The requirement that made this project special was that the measurements had to be performed with the disconnector in closed position and at 5000 Amps. Total height of the unfolded disconnector was 5,76 meters. To simulate field application, the disconnector had to be connected to a trapeze being the fixed contact, hanging on an aluminum busbar. Total height of the test set up was 6,60 meters which forced us to make use of the light dome in the ceiling to make it all fit and have acceptable clearance for free air above test object.

The preparation of the test set up has been done together with the customer. A risk assessment has been completed prior to the start of the work to avoid accidents. By use of 2 material lifts the aluminum busbar and trapeze  were elevated into the light dome. The current was induced by 5 current transformers in series to gain enough voltage to overcome the impedance of the test object.  Copper bars specially prepared by the customer were used to close the test circuit connecting the aluminum busbar on the base of the Pantograph to the aluminum busbar in the top. The object required about 5 hours at 5000A to reach thermal stability and it was concluded that temperature rises where within the required limits based on clause 6.5 of IEC62271-102.