Measurement of dielectric loss connection
There are two connection methods for dielectric loss measurement: positive connection and reverse connection. The principle connection diagram can be found in the instruction manual. When both poles of the tested item are insulated from the ground (such as a high-voltage bushing, which is lightweight and can be placed on an insulating support for measurement), the positive connection method can be used; when one pole of the tested item is grounded, the reverse connection method must be used. In the production site, the tested electrical equipment is usually grounded at one pole (such as the metal casing of power transformers, transformers, and multi-oil circuit breakers, etc. are all grounded), so in the field, the reverse connection method is usually adopted for dielectric loss tests.
The anti-interference multi-frequency dielectric loss tester has high voltage between HV and CX, as well as between HV and CN. The potential between the connection line from CX socket to the CX of the tested item (terminal marked as CX) and the shielding layer of the connection line (terminal marked as E) is nearly equal. Users can adopt different grounding methods according to measurement needs.
When using the “positive connection method” for measurement, the “E” point can be grounded. At this time, there is high voltage between the wire and the ground. When using the “reverse connection method” for measurement, the red wire of the red cable (HV point) can be grounded; the red wire of the black cable (CX) is connected to the high-voltage end of the test object; the black wire of the black cable (E point) is left floating; at this time, there is high voltage between the shield layer E of the CX wire and the ground, as well as between the shield layer E and the internal shield of the instrument (which is not necessarily connected to the instrument shell; it depends on the measurement requirements).
Precautions during the experiment
When using the instrument, it is essential to ensure that the grounding terminal is properly grounded, and all other connection points should also be firmly and reliably connected.
Only when the instrument power is turned off and the internal high-voltage enable switch is set to the “off” position, can the rear part of the instrument, the measurement cable, and the test sample be considered safe.
When using the anti-interference inter-frequency dielectric loss tester for measurement, it is strictly prohibited to operate the “test voltage” selection switch.
The positive connection method uses HV lines to carry high voltage, while the reverse connection method uses CX lines and the shielding E line to carry high voltage. When using, it is necessary to ensure that the cables carrying high voltage maintain an adequate distance from the grounding point according to the measurement connection method.
It is not allowed to replace the fuse tubes that do not match the panel’s indicated values.
When using, try to use the cables provided by the manufacturer with the instrument to ensure measurement accuracy.
Post time: Jul-08-2026