Medium Voltage Current Transformer Testing

A transformer substation heat run test requires the transformer mv and lv switchboards to be tested at the same time with defined currents.

Medium voltage current transformer testing.

The importance of instrument transformer tests is often underestimated. Temperature rise test of transformer is included in type test of transformer. Temperature rise test of transformer. In this test.

The test is successful if no breakdown occurs at full test voltage during the test. 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. 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. Phase angle check shall be done for correct direction.

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. A current transformer without primary conductor but with primary insulation of its own which can be used as a bushing. 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. Instrument transformers current transformer.

After commissioning secondary current measurement shall be carried out in ct circuits. Go to content 5. 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. Go to content 4.