Page 81 - Practical Power System and Protective Relays Commissioning

78 Practical Power System and Protective Relays Commissioning

FIGURE 6.13 Sheath voltage limit insulation test.

FIGURE 6.14 High voltage resonant AC test for cables.

6.4.10 High-Voltage Resonant AC Test for 132 kV Cables
and Above
The following steps should ensure this test is carried out in a safe way:
1. Jumper-lead all SVLs of the cable system under test and restore the case
after test.
2. Before and after the high-voltage test, measure and register the cable
insulation resistance.
3. AC 260 kV at 20 300 Hz frequency as shown in Fig. 6.14 shall be
applied for 60 minutes through a frequency-tuned series resonant test set
between the conductor and the metallic sheath of each individual XLPE
cable.
4. All cable conductors and shields not on test shall be grounded.

Refer to Fig. 6.14.

6.5 HIGH VOLTAGE DC POWER SYSTEMS TRANSMISSION

6.5.1 Introduction
A DC transmission consists of converters, inverters, lines with two conduc-
tors and is used economically for long transmission lines.