CNV 508N4 for IEC 60255-22-1

The CNV 508N4 is a special coupling/decoupling network being used to perform "Electrical disturbance tests for measuring relays and protection equipment" in accordance to IEC 60255-22-1. A capacitance of 0.5uF is specified to couple the pulses on to the lines. Each line has a decoupling inductor of >1.5mH to protect the auxiliary equipment from being subjected to the test pulse. The disturbance signal used for this test is a damped oscillatory pulse with a frequency of 1MHz, generated by the EM TEST OCS 500M6.
Depending on the configuration of the DUT several different test set-up's are used to perform tests in differential mode (line-to-line of the same pair) or common mode (each pair to ground or one pair to all other pairs with these being grounded). The CNV 508N4 is automatically set by the OCS 500M6 selecting the desired coupling mode and lines to be coupled. The coupler offers capability to test up to 4 pairs/8 lines.

The test of measuring relays and protection equipment as outlined in IEC 60255-22-1 includes different coupling modes to test the DUT under different conditions. Each pair of lines is tested individually in differential mode. Common mode test is applied to each pair to ground and to each pair with the other pairs connected to ground.
The EM TEST CNV 508N4 is a dedicated CDN for these applications, fully automatic, remote controlled by the OCS 500M6 for the various coupling modes. This offers best user convenience and reliability that all couplings required are tested sequently. The selected coupling mode and lines actually being tested are indicated by LEDs.

The CNV 508N4 includes the required 1.5mH decoupling inductors to decouple the auxiliary equipment as well as the coupling part via a 0.5uF capacitor for each line and the coupling relays to allow all possible settings for differential mode and common mode testing as per IEC 60255-22-1. The coupling mode and the coupling of the lines are selected and controlled via the OCS 500M6.