Partial Discharge in Cables

1. Cable Testing Requirements and Preparations Before Testing

1）Prior to partial discharge testing, disconnect and ground the cable, leaving both ends suspended, and set up the safety perimeter.

2) Aim to minimize the cable joint areaPTDemolition of lightning arresters and other equipment

3) The cable head is cleaned, ensuring sufficient insulation distance between the cable head and the surrounding grounding parts.

4) Gather cable parameters such as length, model, type, and commissioning date.

5) Cable Length L: Measurement method on one side of the cable: 50m ≤ L ≤ 3km;

Cable End Measurement Method:L＞3km。

2. Insulation Resistance Testing

10kV Cable Main Insulation Resistance Test: Utilizing a 2500V insulation megger for testing, the insulation resistance should show no significant change before and after the test; for the 10kV cable main insulation resistance test, the insulation resistance must be greater than 50MΩ to proceed to the next phase of testing.

3. Test the intermediate joint position of the cable and cable length

AdoptedSEBAKMT Easyflex ComMultifunctional Pulse Reflectometer (as shown in the figure)2) Conducted tests on the full length of the cable and the positions of its intermediate joints to measure cable length and joint locations, as well as to pre-locate faults of short-circuit and open-circuit in the cable.

Testing Requirements:

The full length of the cable must be accurate for calibration purposes.

2) Intermediate joint measurements should be as accurate and detailed as possible, which is beneficial for ultimately determining the partial discharge location.

3) Measurement Range:50m～15000mThe measurement range must be adjusted according to the cable length.