Medium Voltage Current Transformer Testing

Common specifications for hv switchgear.

Medium voltage current transformer testing.

Go to content 4. Indoor current transformers bushing type bb and bbo medium voltage current transformers bushing type bb and bbo are cast in epoxy resin and are designed for installation voltage up to 24 kv 25 kv. In this test. Some distribution voltages may exceed 35 kv and would be considered high voltage but most of the distribution system is within the medium voltage range.

A current transformer without primary conductor but with primary insulation of its own which can be used as a bushing. The importance of instrument transformer tests is often underestimated. Temperature rise test of transformer. Instrument transformers current transformer.

Ct s are instrument transformers used for converting primary current into a reduced secondary current for use with meters relays control equipment and other instruments. A transformer substation heat run test requires the transformer mv and lv switchboards to be tested at the same time with defined currents. Phase angle check shall be done for correct direction. Two ac power supplies are needed one high power supply for the mv switchgear and the transformer in short circuit and a high current supply for the lv switchboard.

Temperature rise test of transformer is included in type test of transformer. The test is successful if no breakdown occurs at full test voltage during the test. Th e test shall start with a voltage lower than 1 3 the full test voltage and it shall be quickly increased up to the desired value. Current transformers play an important role in the monitoring and protection of electrical power systems.