Medium Voltage Current Transformer Testing

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.

Medium voltage current transformer testing.

Instrument transformers current transformer. The test is successful if no breakdown occurs at full test voltage during the test. After commissioning secondary current measurement shall be carried out in ct circuits. Go to content 5.

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. 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. 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. The importance of instrument transformer tests is often underestimated. In this test. Practical levels of voltage are often referred to as medium voltage meaning the incoming voltage to the transformer is on the order of 5 kv to 35 kv.

A current transformer without primary conductor but with primary insulation of its own which can be used as a bushing. Current transformers play an important role in the monitoring and protection of electrical power systems. Temperature rise test of transformer. 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.