Mutual Coupling

Selective and reliable distance protection of your double circuit line only works if the coupling impedance of the zero sequence system between two lines is taken into account. Especially for double circuit overhead lines, there is significant inductive and resistive coupling between the two systems.

Distance protection relays, which are capable of compensating the mutual coupling, are measuring the current of the parallel line. As a result of this the voltage caused by coupling can be corrected in order to avoid over- and underreach.

The determination of your double circuit lines parameters is quite similar to the single circuit line procedure. You only have to measure one additional loop which represents the coupling between the two systems. Based on these loop impedances, our test system finally calculates your required double circuit line parameters.

이 솔루션의 이점

Accurate distance protection relay settings

For accurate distance protection relay settings of double circuit lines, it is not only important to measure the sequence impedance but also the mutual coupling impedance.

Mutual coupling measurement

By connecting the CPC 100 and CP CU1 to just one circuit, you can measure the mutual coupling of the double circuit line and the sequence impedance of the single circuit via a clever measurement protocol.

Robust against noise

The CPC 100 + CP CU1 system is able to perform measurements at variable frequencies, which also makes it a robust tool against noise from surrounding live parts or neighboring lines

Safe testing

In the case of unexpected electrical events on overhead transmission lines, such as lightning, the included CP GB1 and CP CU1 protect you and your equipment.

Literature

CP CU1 Brochure (1 MB)