1. Product Uses and Features
Copper core cross-linked polyethylene insulated polyvinyl chloride sheathed power cables with rated voltage 8.7/10kV and below are mainly used for the design of power supply main lines fixedly laid in mines, bearing the “main artery” responsibility for power transmission, and on the basis of the advantages of ordinary cross-linked cables, incorporate the mandatory safety attributes of mining cables.
2. Product Standards
MT 818.13-1999
3. Product Models and Names
Model | Name |
MYJV | Cross-linked polyethylene insulated polyvinyl chloride sheathed power cable for coal mine use |
MYJV22 | Cross-linked polyethylene insulated steel tape armored polyvinyl chloride sheathed power cable for coal mine use |
MYJV32 | Cross-linked polyethylene insulated fine steel wire armored polyvinyl chloride sheathed power cable for coal mine use |
MYJV42 | Cross-linked polyethylene insulated fine steel wire armored polyvinyl chloride sheathed power cable for coal mine use |
Table 1
4. Product Specifications
Type No. | Core Number | Rated Voltage kV | ||
0.6/1 | 1.8/3 | 3.6/6、6/6、6/10、8.7/10 | ||
Nominal Cross-section 2mm | ||||
MYJV | 3 3 3 3 | 1.5~300 | 10~300 | 25~300 25~300 25~300 50~300 |
MYJV22 | 2.5~300 | 10~300 | ||
MYJV32 | 16~300 | 16~300 | ||
MYJV42 | 50~300 | 50~300 | ||
MYJV MYJV22 | 3+1 3+1 | 4~300 4~300 | 10~300 10~300 | - - |
MYJV MYJV22 | 4 4 | 4~185 4~185 | 4~185 4~185 | - - |
Table 2
5. Technical Requirements
5.1 Conductor
The conductor shall comply with the provisions of 5.1 in MT 818.11-2009.
5.2 Insulation
5.2.1 The insulation shall be of XLPE type. The insulation performance shall comply with the provisions of Table 14 and Table 17 of MT 818.11-2009.
5.2.2 The insulation thickness shall comply with the provisions of 5.2.2 in MT 818.11-2009 and Table 3 of this part.
5.2.3 There shall be no visible defects such as bubbles and sand holes on the cross-section of the insulation layer.
5.3 Screening
5.3.1 Conductor Screen
5.3.1.1 Cables with rated voltage U0 of 3.6kV and above shall have a conductor screen.
5.3.1.2 The conductor screen shall be of semi-conductive material, shall be tightly extruded on the conductor, the surface shall be smooth, with no obvious stranding ridges, and there shall be no marks of sharp corners, particles, burns or abrasions.
5.3.2 Insulation Screen
5.3.2.1 Cables with rated voltage U0 of 3.6kV and above shall have an insulation screen.
5.3.2.2 The insulation screen is an extruded semi-conductive layer.
5.3.2.3 The insulation screen of the cable shall comply with the requirements of b) in 6.4.3.11 of MT 818.11-200x.
5.3.3 Metallic Screen
5.3.3.1 Cables with rated voltage U0 of 1.8kV and above shall have a metallic screen layer. The metallic screen is of copper tape screen structure.
5.3.3.2 The copper tape screen consists of overlapping wrapped soft copper tapes. The nominal thickness of the copper tape is 0.1mm, and its average thickness shall not be less than 90% of the specified nominal value.
5.4 Cable Core and Inner Covering
The cable core and inner covering shall comply with the provisions of 5.4 in MT 818.11-2009.
Table3 Nominal insulation thickness
Conductor nominal Cross section mm2 | Rated voltage kV | ||||
0.6/1 | 1.8/3 | 3.6/6 | 6/6、6/10 | 8.7/10 | |
Nominal insulation thickness mm | |||||
1.5 | 0.7 | — | — | — | — |
2.5 | 0.7 | — | — | — | — |
4 | 0.7 | — | — | — | — |
6 | 0.7 | — | — | — | — |
10 | 0.7 | 2.0 | — | — | |
16 | 0.7 | 2.0 | — | ||
25 | 0.9 | 2.0 | 2.5 | 3.4 | 4.5 |
35 | 0.9 | 2.0 | 2.5 | 3.4 | 4.5 |
50 | 1.0 | 2.0 | 2.5 | 3.4 | 4.5 |
70 | 1.1 | 2.0 | 2.5 | 3.4 | 4.5 |
95 | 1.1 | 2.0 | 2.5 | 3.4 | 4.5 |
120 | 1.2 | 2.0 | 2.5 | 3.4 | 4.5 |
150 | 1.4 | 2.0 | 2.5 | 3.4 | 4.5 |
185 | 1.6 | 2.0 | 2.5 | 3.4 | 4.5 |
240 | 1.7 | 2.0 | 2.6 | 3.4 | 4.5 |
300 | 1.8 | 2.0 | 2.8 | 3.4 | 4.5 |
5.5 Armor
The cable armor shall comply with the provisions of 5.5 in MT 818.11-2009.
5.6 Non-metallic sheath
The sheath shall be made of ST2 type material, and its thickness shall comply with the provisions of 5.6 in MT 818.11-2009, and its performance shall comply with the provisions of Table 15 and Table 16 in MT 818.11-2009.
5.7 Operating conditions
5.7.1 The maximum rated operating temperature of the cable conductor is 90℃.
5.7.2 During short circuit (maximum duration not exceeding 5s), the maximum temperature of the cable conductor shall not exceed 250℃.
5.7.3 The ambient temperature when laying cables shall not be lower than 0℃, and the minimum bending radius shall be 15 times the cable diameter.
6 Test methods and inspection rules
The cable shall be tested in accordance with the provisions of Table 4 to check whether it meets the corresponding requirements. The inspection rules shall comply with the provisions of Chapter 6 in MT 818.11-2009.
Table4 Test items
Serial number | Item name | Test requirements | Test type | Test method | ||||
Standard number | Clause number | 0.6/1 | 1.8/3 | 3.6/6 | 6/6~8.7/10 | |||
1 | Conductor DC resistance | MT 818.11 | 6.2.1 | R | R | R | R | GB/T 3048.4 |
2 | Partial discharge test | MT 818.11 | 6.2.2 | — | — | R | R | GB/T 3048.12 |
3 | AC voltage test | MT 818.11 | 6.2.3 | R | R | R | R | GB/T 3048.8 |
4 | Structure and dimension inspection | |||||||
4.1 | Conductor structure | MT 818.11 | 6.3.2.1 | S | S | S | S | Visual inspection |
4.2 | Insulation thickness | MT 818.11 | 6.3.2.2 | S | S | S | S | GB/T 2951.1 |
4.3 | Armor | MT 818.11 | 6.3.2.3 | S | S | S | S | GB/T 2951.1 |
4.4 | Sheath thickness | MT 818.11 | 6.3.2.4 | S | S | S | S | GB/T 2951.1 |
5 | 4h AC voltage test | MT 818.11 | 6.3.3 | — | — | — | S | GB/T 3048.8 |
6 | Hot elongation test | MT 818.11 | 6.3.4 | S | S | S | S | GB/T 2951.5 |
7 | Flame retardant performance test | |||||||
7.1 | Single vertical burning test | MT 818.11 | 6.3.5 | S | S | S | S | MT 386 |
7.2 | Burning test under load conditions | MT 818.11 | 6.3.5 | S | S | S | S | MT 386 |
8 | Structure and dimension inspection | MT 818.11 | ||||||
8.1 | Insulation thickness | MT 818.11 | 6.4.6.1 | T | T | T | T | GB/T 2951.1 |
8.2 | Sheath thickness | MT 818.11 | 6.4.6.2 | T | T | T | T | GB/T 2951.1 |
9 | Partial discharge test | MT 818.11 | 6.4.1.4 | — | — | T | T | GB/T 3048.12 |
10 | Partial discharge test after bending test | MT 818.11 | 6.4.1.5 | — | — | T | T | GB/T 2951.23 and GB/T 3048.8 |
11 | tanδ test | MT 818.11 | 6.4.1.6 | — | — | — | T | GB/T 3048.11 |
12 | Partial discharge test after thermal cycling | MT 818.11 | 6.4.1.7 | — | — | T | T | GB/T 3048.12 |
13 | Impulse voltage and AC voltage test | MT 818.11 | 6.4.1.8 | — | T | T | T | GB/T 3048.13 |
14 | 4h AC voltage test | MT 818.11 | 6.4.1.9 | T | T | T | T | GB/T 3048.8 |
15 | Semiconducting screen resistivity test | MT 818.11 | 6.4.1.10 | — | — | T | T | GB/T 12706.2 Appendix C |
16 | Conductor DC resistance test | MT 818.11 | 6.4.1.11 | — | — | T | T | GB/T 3048.4 |
17 | Insulation resistance test at maximum rated temperature | MT 818.11 | 6.4.2.3.3 | T | T | — | — | GB/T 3048.5 |
18 | Impulse voltage and AC voltage test | MT 818.11 | 6.4.2.5 | — | T | — | — | GB/T 3048.13 |
19 | 4h AC voltage test | MT 818.11 | 6.4.2.4 | T | T | — | — | GB/T 3048.8 |
20 | Conductor DC resistance test | MT 818.11 | 6.4.2.6 | T | T | — | — | GB/T 3048.4 |
21 | Insulation mechanical and physical properties test | |||||||
21.1 | Mechanical properties test before aging | MT 818.11 | 6.4.3.1 | T | T | T | T | GB/T 2951.1 |
21.2 | Mechanical properties test after aging | MT 818.11 | 6.4.3.1 | T | T | T | T | GB/T 2951.2 |
22 | Sheath mechanical and physical properties test | |||||||
22.1 | Mechanical properties test before aging | MT 818.11 | 6.4.3.2 | T | T | T | T | GB/T 2951.1 |
22.2 | Mechanical properties test after aging | MT 818.11 | 6.4.3.2 | T | T | T | T | GB/T 2951.2 |
23 | Additional aging test on finished cable section | MT 818.11 | 6.4.3.3 | T | T | T | T | MT 818.11 in 6.4.3.3 |
24 | ST2 type PVC sheath mass loss test | MT 818.11 | 6.4.3.4 | T | T | T | T | GB/T 2951.7 |
25 | PVC sheath high temperature pressure test | MT 818.11 | 6.4.3.5 | T | T | T | T | GB/T 2951.6 |
Table4(continued) Test items
Serial number | Item name | Technical requirements | Test type | Test method | ||||
Standard number | Clause number | 0.6/1 | 1.8/3 | 3.6/6 | 6/6~8.7/10 | |||
26 | PVC sheath low temperature performance test | MT818.11 | 6.4.3.6 | T | T | T | T | GB/T 2951.4 |
27 | PVC sheath crack resistance(thermal shock) test | MT818.11 | 6.4.3.7 | T | T | T | T | GB/T 2951.6 |
28 | XLPE insulation water absorption test | MT818.11 | 6.4.3.8 | T | T | T | T | GB/T 2951.3 |
29 | XLPE insulation shrinkage test | MT818.11 | 6.4.3.9 | T | T | T | T | GB/T 2951.3 |
30 | XLPE insulation hot elongation test | MT818.11 | 6.4.3.10 | T | T | T | T | GB/T 2951.5 |
31 | Semiconducting layer stripping test | MT818.11 | 6.4.3.11 | — | — | T | T | MT 818.11 in 6.4.3.11 |
321) | Special bending test | MT818.11 | 6.4.3.12 | T | T | — | — | MT 818.11 in 6.4.3.12 |
33 | Printed marking abrasion resistance test | MT818.11 | 6.4.4 | T | T | T | T | GB 6995 |
34 | Flame retardant performance test | |||||||
34.1 | Single vertical burning test | MT818.11 | 6.4.5 | T | T | T | T | MT 386 |
34.2 | Burning test under load conditions | MT818.11 | 6.4.5 | T | T | T | T | MT 386 |
34.3 | Bunched cable burning test | MT818.11 | 6.4.5 | T | T | T | T | MT 386 |
Note: Sequence number32 only applies to cables with the structure specified in 5.4.3 of MT 818.11. | ||||||||
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