Underground Power Cable Site Test after Installation:
Many cable failures are the result of poor installation practices; so, all new installations should be thoroughly tested before they are put into service. Since the cable itself will have been tested at the factory, on-site testing of newly installed cables focuses on identifying localized problems that have occurred during installation.
Site test after installation of the underground power cable is required to confirm that the line is installed correctly and there is no damage during laying.
The following site test should carry out for the underground cable after installation:
1. Phase Checking Test
2. 10 kV Sheath Integrity Test
3. Insulation Resistance Test
4. DC High Voltage Test
5. No load Test
For safe and effective energization of underground cable power line site test after installation is necessary.
Safety:
- Correct phasing and identification of a three-phase cable system, without having to remove any safety grounds on the cable
- Prevents the user from inadvertently changing gain/sensitivity settings
- Connection error notification– instrument notifies the operator of a poor connection hookup
Phase Checking: The correct identification of a cable along its length is often required for various applications - including, but not limited to: the need to cut or "spike" cable to install a new transformer, switch/splice into an existing cable, or to identify the location of the phases in a cable(s) prior to spiking/cutting.
Sheath Integrity Test: A sheath test to indicate whether there has been any mechanical damage to the cable outer sheath during installation is the first test that should be performed on newly installed cables.
Insulation Resistance Test: IR test is conducted using an IR tester, the IR tester is a portable ohmmeter (MΩ.km) with a built-in generator that produces a high DC voltage. The DC voltage usually measures 500V and causes a current to flow around the surface of the insulation.
No load Test: No load test means the cable keeps a certain time period (normally 24 hours) without any load, just charging with nominal voltage.
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