FIELD OF INVENTION
Thepresent disclosurerelatestopower cables,morespecificallythedisclosurerelatestoa system and method to rejuvenate the insulation of the power cables.
BACKGROUND
Presently the power cables are either laid over the poles or underground. The power cables laid on the poles are easy to maintain and replace. However, even with more issues associated with maintenance of the underground cables, it's the more preferred way.
The underground power cables are affected by the moist and damp environment in the soil. Since most of the power cables have insulation of Cross-Linked Poly-Ethylene, they are affected by the water ingress, if occurs at any point of time. Further ingress of the moisture and dust during the jointing or maintenance of the power cable affect the insulation. The ingress water/moisture in the insulation enables water seepage and cause tree like structure with branches in the XLPE insulation which can be called us water tree. This water tree in presence of AC electric filed converts into electrical tree & further deterioration of XLPE insulation. This water tree issue in the insulation can be observed under the microscope.
However, in order to fix the problem, the entire segment of the power cable may need to be replaced at times which result in additional maintenance cost.
SUMMARY
This summary is provided to introduce aspects related to rejuvenation of the insulation of the power cables and the aspects are further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.
In one implementationdevelopment of silicone compound on the basis of appropriate membrane formation, viscosity and insulation properties is disclosed.

Further in accordance with the present disclosure to inject the silicone composition into the insulation certain steps have to be followed. Firstly, a trend analysis of cable failure is performed. The trend analysis may be basedon Maximum joints, no. of faults and level of faults. Further based on these multiple factor, a Prioritization matrix may be prepared to enlist the criterion for cable rejuvenation. Further at a second step diagnostic testing may be performed for precise identification of the nature of abnormalities /contamination. The test may comprise of Polarization Index (PI), and/or DC Leakage Current & Signature analysis using Time Domain Reflectometer (TDR).At a third step in order to rejuvenate the insulation of the cable or the cable, moisture from Conductor, Screen & Outer Jacket is eliminated, sinceits presence may damage the cable. To remove the moisture a vacuum pump may be used to extract the water from the conductor. The Vacuum pressure in the pump may be maintained between 0.2 to 0.6 bar for about 20 minutes per core keeping the other end sealed using Silica Gel to prevent moisture entry.
Further in a fourth step the cable may be purged with nitrogen for curing. The purging may be done at the pressure of 1.5 bar to prevent oxidation and ensure complete removal of residual moisture. Lastly the silicone composition may be injected into the cable. The silicone composition may react with the moisture left in the insulation after purging to form a membrane. The Silicone composition in presence of moisture hydrolyses and condenses to form an insulating film thus enhancing the dielectric property of the insulation.
Referring to Figure 1, illustrates a vacuuming apparatus in accordance with the present disclosure. The vacuuming apparatus enables the cable rejuvenation system to remove moisture from the cable. A segment of the underground cable is detected for splices and neutral corrosion. The splices may be detected using a RF locator and pinpointed by a measuring wheel. Each segment of the cable may be about 7 meters to 10 meters, and may be exposed by digging up the segment. Further a vacuum pump may be connected to a first opening of the cable. The other end of the affected cable may be sealed using silica gel container in order to avoid ingress of fresh moisture into the cable. The pressure of the vacuum pump is set in a range of 0.2 bar to 0.6 bar. The vacuum pump is operated to a pre-determined time until the moisture or air removed from the cable that needs to be rejuvenated.
Referring to Figure 2, illustrates a purging apparatus in accordance with the system. The purging apparatus may comprise a nitrogen cylinder, configured to pump nitrogen into the test cable. The nitrogen gas at a pressure of 1.5 bar is directly pumped into the cable.
Now referring to Figure 3, illustrates an apparatus for silicone injection, in accordance with the present disclosure. The silicon composition of PDMS and TEOS is injected into the test cable

through the first end. The second end is kept open to check the passage of vapour composition as the same will come out from other end.

We Claim
1. A system for rejuvenation of cable insulation, the system comprising:
a vacuuming apparatus, wherein a pump set is configured to create a vacuum;
a purging apparatus, wherein the pump set is further configured to pump
nitrogen; and
a silicone injection apparatus, wherein the pump set is further configured to inject
silicon.
2. The system as claimed in claim 1, wherein the vacuuming process is followed after the detection of splices through a RF locator, and a measuring wheel to pinpoint exact location of splices.
3. The system as claimed in claim 1, wherein the vacuuming apparatus, further comprises exposing a segment of a cable and connecting to a first opening of the cable.
4. The system as claimed in claim 3, wherein the vacuuming apparatus, wherein the other end of the cable is sealed using silica gel container.
5. The system as claimed in claim 1, wherein the pressure of the pump is set in a range of 0.2 bar to 0.6 bar.
6. The system as claimed in claim 1, wherein the nitrogen gas is directly purged into the test cables from the nitrogen cylinder at a pressure of 1.5 bar.
7. The system as claimed in claim 1, wherein the vapour pump set injects a silicon composition of PDMS and TEOS into the cable through the first end.
8. The system as claimed in claim 7, wherein the second end is kept open to measure the effectiveness through the passage of chemical vapour from one end to other.