JB/T 7830-1995 Straight-through heat shrinkable joints for power cables with rated voltage up to and including 8.7/10kV
Some standard content:
Mechanical Industry Standard of the People's Republic of China
Straight-through heat shrinkable joints for power cables with rated voltages of 8.7/10kV and below
1 Subject content and scope of application
JB7830-1995
This standard specifies the product marking and code, technical requirements, test methods, inspection rules and markings, packaging, transportation and storage of straight-through heat shrinkable joints for power cables with rated voltages of 8.7/10kV and below. This standard applies to straight-through heat shrinkable cable joints for plastic insulated power cables with rated voltages U/U of 8.7/10kV and below, and the use conditions shall comply with Article 4.1 of GB11033.1. 2 Reference standards
GB2900.10
GB11033
GB14315
GB5589
GB9327
GB1040
GB5470
GB2411
GB1034
GB1408
GB1409
GB1410||tt ||GR7141
GB10707
GB4507
GB4509
GB2790
3 Terminology
Electrical terminology Part 10 Basic technical requirements for wires and cables with rated voltage of 26/35kV and below Power cable accessories Compression-type copper and aluminum terminals and connecting tubes for power cable conductors Test methods for cable accessories
Compression and mechanical connection of cable conductors Joint test methodsHigh voltage test technologyPart 2Test procedureTensile test method for plastics
Test method for impact brittleness temperature of plastics
Test method for Shore hardness of plastics
Test method for water absorption of plastics
Test method for power frequency electrical strength of solid insulating materialsTest method for relative dielectric constant and dielectric loss factor of solid insulating materials at power frequency, audio frequency and high frequency (including meter wavelength)
Test method for volume resistivity and surface resistivity of solid insulating materialsTest method for resistivity of semi-conductive rubber and plastic materials of wires and cablesTest method for hot air aging test of plastics (heat aging chamber method)General rulesDetermination of combustion performance of rubberOxygen index method
Determination of softening point of petroleum asphalt
Determination of needle penetration of petroleum asphalt
Determination method for 180 degree peel strength of adhesive
Except the terms specified in this standard, other terms shall comply with the provisions of GB2900.10 and GB11033.1. 3.1 Heat shrinkable parts
Heat shrinkable parts are made of polymer as the basic material and are made into the required profiles. After the cross-linking process, the linear molecules of the polymer are transformed into the body molecules of the network structure. After heating, they are expanded to the specified size, and then heated to shrink to the predetermined size. 3.2 Heat shrinkable insulation tube (referred to as insulation tube in this standard) Approved by the Ministry of Machinery Industry on November 24, 1995
Implementation on July 1, 1996
JB7830-1995
As a tubular heat shrinkable part for electrical insulation. 3.3 Heat-shrinkable semi-conductive tube (referred to as semi-conductive tube in this standard) is a tubular heat-shrinkable component with a volume resistivity less than 10\n·cm. 3.4 Heat-shrinkable stress control tube (referred to as stress tube in this standard) is a tubular heat-shrinkable component with corresponding dielectric constant and volume resistivity, which can alleviate the electric field concentration at the cable end and joint. Heat-shrinkable sheath tube (referred to as sheath tube in this standard) 3.5
is a tubular heat-shrinkable component that serves as a seal and has a certain mechanical protection effect. 3.6 Hot melt adhesive
is used with heat-shrinkable components to ensure that the interface is tightly bonded after heating and shrinking, and plays a role in sealing, leakproof and moisture-proof. 3.7 Filling adhesive
is used with heat-shrinkable components to fill the gaps at the interface joint after shrinkage. 4
Product marking and code
4.1 Code
4.1.1 According to series
Straight-through connector series
4.1.2 According to process characteristics
Heat shrink type...
4.1.3 According to the type of supporting cables
Plastic insulated power cable
4.1.4 According to the order of design|| tt||1st design.
2nd design
(and so on)
4.1.5Classification by voltage level
1.8/3kV and belowwww.bzxz.net
3.6/6, 6/6, 6/10kV.
8.7/10kV...
4.1.6Classification by cable core
5 core·
4. 2 Product representation method
4.2.1 The composition and arrangement sequence of product models are as follows: ·RS
JB7830—1995
Cable core number code
Voltage level code
Design sequence code
Matching cable variety code
Process characteristic code
Series code
4.2.2 Example
JB7830-1995
8.7/10kV3-core plastic insulated power cable straight-through heat shrinkable joint, second design, represented as: JRS—2--33
5 Technical requirements
JB7830—1995
In addition to complying with the requirements of GB11033 standard, straight-through heat shrinkable joints shall also comply with the following provisions. 5.1 All heat shrink components, hot melt adhesives, filling adhesives, etc. used in straight-through heat shrink joints shall comply with the requirements of Appendix A to Appendix C of this standard, and all joint materials and components shall be supplied in a matching package. 5.2 Conductor connection fittings shall comply with the corresponding provisions in GB14315, and the DC resistance of the copper-aluminum transition connection tube shall not be greater than 1.2 times the DC resistance of the aluminum conductor of the same length and cross-section.
5.3 See Appendix E for the basic requirements for the installation process of straight-through heat shrink joints. 5.+Bridge line
The bridge line of the joint (the metal shield connection line of the cable at both ends of the joint) shall be made of tin-copper wire, and its recommended cross-sectional area shall be selected according to the provisions of Table 1, or it may be selected according to the principle of the same cross-sectional area as the cable metal shielding layer. Table 1
Cable main line core cross-sectional area
35 and below
50~120
150~400
50 and below
70~150
185~400
Cross-sectional area of bridge wire
Note: When the cross-sectional area of the metal shielding of the connector meets the cross-sectional area of the bridge wire specified in Table 1 or is equal to the cross-sectional area of the electrical metal shielding layer, the bridge wire can be omitted. 5.5 Protection box
When the user requires it, the corresponding mechanical protection box should be provided. The protection box should be impact-resistant. In the impact test, the protective layer should not be damaged or penetrated after 6 impacts.
5.6 Electrical performance
According to the installation process instructions provided by the manufacturer, install the various materials and components of the provided cable connector on the cable of the corresponding specifications with reliable performance and then conduct electrical performance tests. The test items and requirements should comply with the provisions of Table 2 and Table 3. 6 Test methods
6.1 The requirements specified in Article 5.1 shall be tested in accordance with the test methods specified in Appendix D of this standard. 6.2 The requirements specified in Article 5.2 shall be tested in accordance with the test methods specified in GB9327.2. 6.3 The requirements specified in Article 5.5 shall be tested in accordance with the test methods specified in Appendix D of this standard. 6.4 The requirements specified in Article 5.6 shall be tested in accordance with the test series and test methods specified in Table 2 or Table 3. 7 Inspection rules
Products shall be inspected and qualified by the technical inspection department of the manufacturer before leaving the factory, and the products leaving the factory shall be accompanied by a product quality inspection certificate. 7.1 Type test
Products shall be type tested in accordance with the requirements of Articles 5.1, 5.2 and Table 2 of Article 5.6, among which the short-circuit test series shall be determined by negotiation between the supply and demand parties whether to conduct the test. The number of test samples and the evaluation method of test results shall be in accordance with the corresponding provisions in GB11033. 7.2 Sampling test
7.2.1 During normal production, a sampling test should be conducted once every 35 years. It should also be conducted when the user requests it and both parties agree. 7.2.2 Products should be sampled and tested in accordance with the requirements of Article 5.2 and Table 3 of Article 5.6. The number of test products and the method of evaluating the test results should comply with the corresponding provisions in 18
GB11033.
7.3 Routine test
JB7830-1995
Heat shrink components should be routinely tested in accordance with Articles 1, 3, and 7 in Appendix A of this standard. 8 Marking, packaging, transportation, storage
8.1 The main materials and components used for joints should be marked with the brand, name, factory name, and date of manufacture, and be accompanied by a certificate of conformity or an acceptance mark. Materials with a storage period must indicate the date of manufacture and storage period. 8.2 Various heat shrinkable parts, hot melt adhesives, filling adhesives, etc. should be sealed and packaged. Each set of straight-through heat shrinkable joints should be packaged in a special packaging box, which should be accompanied by a material list, a certificate of conformity and an installation process manual. 8.3
The packaging box should indicate:
Manufacturer name;
Product model, name, product standard number; rated voltage;
Conductor material, drum surface and number of cores;
Factory date.
The product should be protected from heavy pressure and violent collision during transportation. 8.5 The product should be stored away from heat sources, and fire prevention measures should be taken, and it should be dry and ventilated. The storage period should not exceed the storage date of the corresponding supporting materials and accessories.
Rated voltage test 1min
Partial discharge test
Constant voltage load cycle test
3 cycles
Partial discharge test
Constant voltage load cycle test
a.60 cycles in air
b.62 cycles in water
Short circuit test
Short circuit thermal stability
Short circuit dynamic stability
0.6/1/3.6/6
6/6, 6/10
(Conductor is heated by current for 5h, cooled
3h, the highest temperature of the conductor during heating is electric
Performance Allowable working temperature plus 5°C)
(The conductor is heated by current for 5h and cooled for 3h. The highest temperature of the conductor during heating is the allowable working temperature of the cable plus 5°C)
(Each sample is short-circuited twice, the current value
Test method
GB11033.1 Section
, under consideration
should comply with the provisions of Table 1 of GB11033.1)
(Each sample is short-circuited once, the current is
Test result evaluation
No breakdown
Discharge at the specified extinguishing voltage
XLPE cable is not more than 2 0PC
PVC cable is not more than 40PC
Assessed by subsequent tests
Discharge at the specified extinguishing voltage
XLPE cable is not more than 20PC
PVC cable is not more than 40PC
Assessed by subsequent tests
Assessed by subsequent tests
Test series
Test item day
Impulse voltage test
1.2/50±10 times
DC voltage test
Negative polarity 15min
Power frequency voltage test 15min
Partial discharge test
Appearance inspection
Rated voltage test 1min
Partial discharge test
Load cycle test
(no voltage) 3 cycles
Partial discharge test
Impulse voltage test
1.2/50μ8±10 times
DC voltage test
Negative polarity 15min
Rated voltage test 4h
JB7830—1995
Continued Table 2
(All cable joint samples need to be inspected after all tests
passed)
GB 311.3 and GB11033.1, Section 6/6, 6/10 (the conductor is heated by electric current for 5h and cooled for 3h. The maximum temperature of the conductor during heating is the allowable working temperature of the electric current plus 5℃) GB11033.1, Section 6/6, 6/10 (the conductor is heated by electric current for 5h and cooled for 3h. The maximum temperature of the conductor during heating is the allowable working temperature of the electric current plus 5℃) GB11033.1, Section 6/6, 6/10 (the conductor is heated by electric current for 5h and cooled for 3h. The maximum temperature of the conductor during heating is the allowable working temperature of the electric current plus 5℃) GB11033.1, Section 6/6, 6/10 (the conductor is heated by electric current for 5h and cooled for 3h. The maximum temperature of the conductor during heating is the allowable working temperature of the electric current plus 5℃)
GB11033.1 No.
GB11033.1 No.
Test result evaluation
No breakdown
No breakdown
Discharge at the specified extinguishing voltage
XLPE cable is not more than 20PC
PVC cable is not more than 40PC
No cracks, deformation
Test result evaluation
No breakdown
At the specified Discharge under the extinguishing voltage
XLPE cable is not more than 20PC
PVC cable is not more than 40PC
Assessed by subsequent tests
Discharge under the specified extinguishing voltage
XI.PF cable is not more than 20PC
PVC cable is not more than 40PC
No breakdown
No breakdown
Test series
Test procedure
JB 78301995
Appendix A
General Technical Requirements for Heat Shrinkable Components
(Supplement)
A1 The surfaces of all heat shrinkable components shall be free of marks and pits caused by poor materials and workmanship. Whether the inner wall of the heat shrinkable component needs to be coated with hot melt adhesive shall be determined according to the specific requirements of the cable accessories. For heat shrinkable components coated with hot melt adhesive, the adhesive layer shall be uniform, and under the specified storage and transportation conditions, the adhesive layer shall not flow away, not stick to each other, and no air gaps shall be generated after heating and shrinking. A2 The main performance indicators of heat shrinkable components are shown in Appendix B, and the main performance indicators of hot melt adhesive and filling adhesive are shown in Appendix C. A3 The wall thickness unevenness of heat shrinkable tubular parts should not be greater than 30%. The wall thickness unevenness is calculated according to formula (A1): M, -M×100% ..
Wherein: M—maximum wall thickness, mm;
Mz minimum wall thickness, mm;
Eu——wall thickness unevenness, %.
A4 The longitudinal change rate of heat shrinkable tubular parts before shrinkage and after shrinkage under unrestricted conditions (i.e. free shrinkage) should not be greater than 5%, and the radial shrinkage rate should not be less than 50%.
The longitudinal change rate is calculated according to formula (A2):
The length before shrinkage, mm;
Wherein: L.
—The length after shrinkage, mm;
The longitudinal change rate, %.
Radial shrinkage rate is calculated according to formula (A3):
Inner diameter of tube before shrinkage, mm,
In the formula, D,—
DInner diameter of tube after shrinkage, mm;
Ep—Radial shrinkage rate, %.
A5The heat shrinkable parts shall not have cracks or cracks during restrictive shrinkage, and shall not break down under the specified withstand voltage mode. A6The shrinkage temperature of heat shrinkable parts shall be 120-140℃. (A2)
A7The filling adhesive shall be provided in tape, and the filling adhesive tape shall be separated by non-adhesive materials for easy operation. Under the specified storage conditions, the filling adhesive shall not flow away or crack.
A8The allowable storage period of heat shrinkable parts, hot melt adhesive and filling adhesive shall be not less than 24 months when the ambient temperature is not higher than 35℃. During the storage period, its performance shall be guaranteed to meet the above requirements. A9 Type tests for heat shrinkable components, hot melt adhesives and filling adhesives shall be carried out in accordance with the requirements of Articles 6, 7, 8 and Appendix B and Appendix C of this Appendix respectively. Under normal production conditions, type tests shall be carried out once every 1 to 2 years. Type tests shall also be carried out when the material formula and process change. 21
Tensile strength
Elongation at break
Brittle temperature
Hardness (Bühler A)
Heat aging in air box
130℃168h
Change rate of tensile strength
Change rate of elongation at break
Volume resistivity
Dielectric constant
Breakdown strength
Heat shock
Oxygen index
160C4h
Water absorption23±2℃24h
After restricted shrinkage
Working pressure resistance1min
Not less than
Not less than
Not greater than
Not greater than
Not greater than
Not greater than||t t||JB78301995
Appendix B
Main performance indicators of heat shrinkable components
(Supplement)
Not less than
Not less than
Not greater than
Not less than
Insulating tube
Component name and performance indicators
Semi-conductive tube
1~10\)
Stress tube
10°~10
No cracking, no fullness, no dripping
No cracking, no cracking
Sheath tube
Note: Except for item 12, all other items are tested on samples taken from heat shrinkable components after non-restrictive shrinkage (free shrinkage). 1) The volume resistivity test method of semi-conductive tube is in accordance with CB3048.3. Appendix C
Main performance indicators of hot melt adhesive and filling adhesive
(supplement)
Needle penetration (25℃100g)
Softening point (ring and ball method)
Volume resistivity
Breakdown strength
Shear strength
Non-metallic materials for heat shrinkable components
Metallic materials for heat shrinkable components
Not less than
Not less than
Not less than
Not less than
1/10mm
Material name and performance indicators
Hot melt adhesive
Filling adhesive
Test method
GB1040
GB1040
GB5470
GB241 1
GB7141
GB1410
GB1409
GB1408
Appendix D to this standard
Article D1
GB10707
GB1034
Appendix D to this standard
Article D2
Test method
GB4509
GB4507
GB1410
GB1408
GB2790
D1 Thermal shock test
D1.1 Apparatus
Forced convection oven, temperature deviation is ± 2°C D1.2 Sample preparation
Cut three sections of 150mm long heat shrink tubing.
JB7830-1995
Appendix D
Test method
(Supplement)
D1.3 Test method
Hang the sample vertically in an oven at 160℃ for 4h, take out the sample, cool it to room temperature, and check whether the sample has cracks, flow or dripping.
D1.4 Evaluation of test results
The sample should not have cracks, flow or dripping. Restricted shrinkage test
D2.1 Instrument and equipment
Forced convection oven, temperature deviation is ±2℃The mandrel for shrinkage test is made of metal material, and the structural dimensions are shown in Figure D1. All edges are required to be smooth and free of burrs. D2.2 Test method
D2.2.1 According to the nominal inner diameter of the sample, select the corresponding mandrel from the table in Figure D1, clean it, and preheat it in a 130°C oven for 30 minutes. Then put the sample on the mandrel and put it in a 130°C oven for 30 minutes. Then take out the sample and mandrel, cool them to room temperature, and check the tightness of the sample and whether there is cracking or cracking. 1. Nominal inner diameter of heat shrink tube; D-
Nominal inner diameter of heat shrink tube
21~100
75% of diameter A; d-
50% of diameter A of the mandrel for shrink test
.
D2.2.2 Wrap the aluminum foil with a thickness of no more than 0.02mm tightly on the test surface of the mandrel at the maximum diameter (section A in Figure D1) in two layers as the outer electrode of the withstand voltage test, and the mandrel as the inner electrode. Apply the power frequency voltage to the specified value at a voltage increase rate of 500V/s, keep it for 1min, observe whether the sample is broken down, and check the breakdown position. 23
D2.2.3 Evaluation of test results
JB 7830-1995
a. The sample and the mandrel should fit tightly and no cracks or cracks should appear; b. The sample should not be broken down.
D3 Impact test
D3.1 Test device
The test device is shown in Figure D2. The impact block is made of steel. There are guide rails on both sides of the support frame to ensure that the impact block falls freely in the specified direction. The top of the support frame is equipped with a pulley for lifting the impact block. Hold the correct direction of the guide
R is 2mr
Connect the sample!
D3.2 Test method
Sand support
Figure D2 Impact test device
D3.2.1 As shown in Figure D2, place the sample under the support frame of the test device, fix the cables at both ends of the sample, and ensure that the sample does not roll during the test.
D3.2.2 Lift the impact block to the specified height (see Figure D2). D3.2.3 Let the impact block fall freely and impact the sample. D3.2.4 Take out the sample and observe whether the anti-corrosion layer of the sample is damaged or penetrated. D3.3'Test result evaluation
After the impact test, the anti-corrosion layer of the sample should not be damaged or penetrated. Appendix E
Main points for installation of straight-through heat shrinkable joints (reference)
This appendix lists the main points to be noted when installing straight-through heat shrinkable cable joints. For specific installation and operation procedures, please refer to the product installation instructions provided by the manufacturer.
E1 Installation tools
E1.1 Heating tools
It is recommended to use a propane gas blowtorch or a high-power industrial hair dryer as a shrinking heating tool for heat shrinkable parts. If conditions are not met, a butane, liquefied gas or gasoline blowtorch can also be used as a shrinking heating tool. E1.2 Conductor connection tools
When the conductor connection is crimped, it is recommended to use a hexagonal or semi-circular confining pressure (also known as ring pressure) mold. The mold size should comply with GB14315. If a point pressure (also known as pit pressure) mold is used, stricter filling and shielding (uniform electric field) measures are required for the pressure pit. E1.3 Insulation stripping tools
When stripping the insulation of plastic insulated cables, it is recommended to use corresponding special stripping tools to ensure that the conductor is not damaged. E1.4 Common tools required for installing cable connectors (such as hand saws, electrician knives, wire cutters, etc.) must be complete and clean. 24
E2 Installation process
JB7830-1995
E2.1 Stripping cables
E2 .1.1 The cable ends shall be stripped in the order specified in the product installation manual. Each process of stripping the cable must ensure that the inner layer that needs to be retained is not damaged.
E2.1.2 When stripping the outer semi-conductive layer of plastic cable insulation, special attention should be paid to ensure that no knife marks or semi-conductive layer residues are left on the exposed insulation surface. If it is a non-peelable semi-conductive layer, it is allowed to remove part of the insulation (thickness not more than 0.5mm) during the stripping process, but the insulation surface should be properly processed as much as possible to make it smooth and round. The end face of the semi-conductive layer after stripping should be perpendicular and flat to the cable axis, and special attention should be paid to not damage the insulation there. If the spraying or brushing semi-conductive paint process is not used, the end face of the outer semi-conductive layer of the cable must be cut smooth and the angle with the cable axis must not be greater than 30°. A rounded cone surface. E2.2 Crimped conductor connecting tube
Use a die-casting crimping conductor connecting tube that matches the cable conductor cross-section, press 3 times on each side and point press 2 times on each side. After crimping, the burrs and metal powder must be removed. E2.3 Install the connector shielding layer and bridge wire
E2.3.1 It is recommended to use a copper wire mesh specially used for electrical accessories as the connector shielding layer, and put the copper wire mesh on (or wrap) the outer semi-conductive layer of the cable connector, and tie and weld it to the copper shielding layer of the cables at both ends to form the connector shielding layer. E2.3.2 For plastic insulated cables with steel tape as the shielding layer, the bridge wire should select the corresponding braided copper wire from Table 1 of this standard according to the cable conductor cross-section and weld it to the shielding copper tape of the cables at both ends. A three-core cable connector can use a bridge wire, but it must Reliable welding with each phase shield of the cable at both ends. If the plastic insulated cable uses copper wire as the shielding layer, the shielding copper wire of each phase cable core at both ends can be twisted and connected with the connecting tube.
E2.3.3 If the user requires the metal shield of the three-core steel-belt armored cable to be insulated from the steel belt, the steel belt connection of the cables at both ends of the joint should also be insulated from the metal shielding layer of the joint. 6-10mm2 insulated soft copper wire can be welded on the steel belt at both ends, or other methods can be used for connection, but it must be ensured that the shielding layer of the joint is insulated. E2.4 Applying filling glue
Filling glue must be used in the following parts of the joint: a. Conductor connection, including the connection tube and the insulation cutting of the cables at both ends; b. The inner sheath and steel belt of the cable where the three cores of the cables at both ends are separated. It is required to wipe the surface of the filled part in advance, and the filling tape must be wrapped tightly and as flat as possible. E2.5 Installing heat shrink tubing
E2.5.1 When the length of the heat shrink tubing is greater than the size specified in the product installation manual, the excess portion can be cut off according to the specified size. The cut should be smooth and without notches. Note that stress tubes cannot be cut off. E2.5.2 The shrink cover surface of the heat shrink tubing should be cleaned in advance and must not have oil stains or debris. When the ambient temperature is below 10°C, the covered object should be preheated.
E2.5.3. Use the heating tool to start from the position specified in the product installation manual, and heat evenly along the circumferential direction. The flame direction should be at an angle of 45° to the axis of the heat shrink tube. Move forward slowly. The flame position must be constantly moved during heating. Do not aim at one position and heat for too long. The surface of the heat shrink tube after shrinkage should be free of burn marks, smooth, flat, and free of bubbles inside. Additional notes:
This standard was proposed and managed by the Shanghai Cable Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Shanghai Cable Research Institute of the Ministry of Machinery Industry. The main drafter of this standard is Ge Guangming.
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