Anti-stress cone mounted within the body can cause the insulation distance T becomes smaller, semi-conductive layer is not on the lap, destroy all masked. If the installation does not match the stress cone, will reduce the stress relieving stress cone, a uniform electric field, leading to excessive concentration of the electric field stress, prone to partial discharge, causing the breakdown. Processing method, see Question 7.
7, forget how to deal with stress cone installed?
Principle amputated crimp terminals reinstalled in exceptional circumstances at the inner surface of the stress cone terminals smear grease, straining into the stress cone installation, provided that the terminal should be smooth, burr is strictly prohibited.This method is used only when forced to, generally the case in the time allowed, should be redone.
8, crimp terminals why should rotate ninety degrees, down from the pressure?
If the direction of maintaining a pressure Next, the crimp terminal section will become flat, smaller flow area, the purpose of rotating the cross-sectional area remains as large as possible.
Pressure from the top down in order to ensure that there are no gaps within the terminal, the terminal portion extending downward, the overall dimensions are not longer.
9, Installing T-body and stress cone Precautions and what is the criterion?
Installation should stress cone ends of the cable conductor wrap with tape to avoid scratching the inner surface of the stress cone. Push the stress cone is exposed to the upper main insulation can, then the end of the stress cone and the cable semi-conductive layer should be reliable semi-conductive layer overlap. Installing T-body, the application of a hand holding the lower end of the stress cone (not upward or downward force), push down on the other hand T body, pushed to the top of the terminal to T body can, at this stress cone should There are about 3m m T of the body exposed in its semi-conducting layer and the semiconducting layer of the main body T is securely lap.
10, the direction is not correct crimp terminal will cause what kind of consequences?
The cable attached to the device when the crimp terminals and the contact surface of the casing to be in close contact. If the orientation is not terminal, the contact surface of the sleeve will be a gap, or by a line contact into a surface contact, the contact resistance becomes large and long-running device will overheat or burning.
11, why American cable accessories for stripping cable size, there are strict requirements?
1) If the cable length of the semi-conductive layer stripping (i.e., semi-conductive layer retained too short), the stress cone and the semiconductive layer can not overlap, can not achieve "to touch, and the unshielded section of the main insulation may be induced potential at both ends of the semi-conductive layer is formed between the electric field stress, long-term operation prone main insulation damage and accidents caused by equipment burned.
2) If the cable semi-conductive layer stripping short (that is, keeping the semi-conductive layer is too long ), will cause the main insulation insulation distance shorter, easier operation creepage, can cause severe insulation breakdown. exploitation size depends entirely on the size of the internal structure of cable accessories, can not be altered.
12, mounting studs too tight or too loose will produce what kind of consequences?
If too much force when installing the studs, the hardness is relatively small due to copper, dismantling will damage the threaded bolt and casing, which does not work properly. If the bolts are not tightened, make the terminals and casing contact resistance increases, the long-running will overheat and even burn.
13, in place of the terminal did not push install insulation adapter plugs or load problems that will arise?
When the terminal is not torn down bit forced installation will be very laborious, but easily the threaded stud screwed bad, and easy to overflow buckle, resulting installation is not in place, and cause overheating at the contact, and even then burned equipment.
14, why the insulating plug can not be used outside of the metal nut pressurized?
Outside the insulating plug is a metal nut installation point, the insulating plug inside a certain insulating distance between the conductor, to ensure the safety nut. Therefore, the metal cap can be applied at the test voltage.
15, spare reserved qualify why must install insulation protection cap?
Distribution boxes aside outlet must install protective cap. Because the device casing running power, if the protective cap installed, can not achieve full insulation and touch, more importantly, not in accordance with the bare tube design operating conditions, when the humidity in the casing reaches a certain level or surface contamination , it will result in discharge breakdown.
16, install live display of test point is how much the normal potential?
Test point voltage is 30 volts, the voltage is induced voltage, the principle of capacitive voltage divider principle.
17, measured with a multimeter cable head test point potential, why numerical flickering? Why different tables have different measurements?
As the potential of the capacitor divider generates, so the degree of exposure of different table pen, the measured value will flicker. Reading should be in accordance with the relative stability of the value read out. Further, since the internal circuit with a multimeter, the resistance measurement precision design, and differences of different tables have different measurements.
18, elbow-type cable head why can serve as a load switch to use?
Elbow-type cable head white part of the conductive rod head arc, arc head with gas production material. Plug in with a load when the head due to the arc extinguishing gas is generated and the arc is extinguished. In case of no current, the plug is mainly the number of the conductive rod and the cable head casing single-pass loss (mechanical life) to determine, pluggable 2000 times. In the case with load, is mainly determined by the electrical life. At full load, the line voltage in the case, can plug 10; at 100 A current, which is not less than 60 times the number of plug; current value of 10A or less, which is 300 times the number of plug.
19, how to ensure the elbow-type conductive rod and head crimp terminal mounting torque?
To ensure the conductive rod with crimp terminal mounting torque should be used elbow-head attachments without the use of a torque wrench to install, upcoming special torque wrench to its original state into a 180-degree angle immediately after.
20, the cable diameter and crimp terminals do not match how to deal with?
Principle must be used with the cable diameter matching crimp terminals. Only in very exceptional circumstances (such as power transmission requires urgent), can be handled as follows: If the size of a small diameter than the terminal can be filled into the terminal after several copper crimp, preferably with 1.0 Cu wire tightly wound after crimping; when large diameter than the size of the terminal, you can remove some copper cable (within the allowable range in carrying capacity) after crimping.
21, test cable accessories do note what?
Test, test leads and cables accessories should be noted that a semi-conductive layer to maintain a certain distance, or prone to breakdown. It is best to install all the cable attachment to the device, and never the other end attachments with American pressure. As American cable accessories in bare casing omissions operating conditions, thus sets off the bare case, pressure test should be carried out in accordance with corporate standards, namely: AC voltage <30KV / m in; DC voltage <35KV / 5min.
22, how to check cable accessories installation is in place?
Elbow-head line should be installed to cover the yellow flag, the installation process can hear "bass" sound, and "on the stage" feeling. T-head should first check the front end is in place, that is closely connected with the casing has been, and then check whether the rear insulation plugs tightened, such as the installation place, exposing T plug body insulation should not exceed 2m m.
23, cable cleaning agents and grease pastes using what precautions?
Cleaning cables and cable accessories, should pay attention to cleaning the direction, the correct way is: From the ends of the wire downward turn cleaning, do not wash back and forth. Cleaning is easy to put forth the tiny semi-conductive layer carbon content to stay in the main insulation, reducing insulation. In the use of silicone grease, all parts in contact surface and the surface should be applied grease, it is the role of insulation, sealing, lubrication.
24, why not use Vaseline instead of grease?
Because cable accessories is the main component EPDM, if Vaseline Council and the ingredients inside a chemical reaction that destroys its organizational structure, reducing insulation.
25, why not replace the dust cap insulating cap?
Dust cap and insulating cap is essentially different, dust cap just before leaving the factory to prevent dust, does not have the role of insulation, insulating cap is entirely in accordance with the operational requirements of the design, and other cable accessories have the same electrical characteristics. Buckle dust cap equivalent to running naked without insulating sleeve cap run, it will cause the device to burn accident (see question 15), so instead of non-insulating cap with dust caps.
26, fault indicator whether the installation location must be in the stress cone tail?
Stress is not necessarily to be installed in the tail cone, can be placed less stress cone, cable trigeminal gloves up anywhere. Site installation is usually installed in the stress cone bottom, looks neat appearance.
27, cable accessories maintenance tools supporting the specification?
Mainly Taps and pull roll. T-head is 5/8 inch, elbow head 3/8 inch. Can be used for stud threaded hole and casing damage repaired.
28, how to solve copper and aluminum cables and terminals with the problem?
In principle, the copper cable using the corresponding specifications of the copper terminals, aluminum cable copper and aluminum terminals with the appropriate specifications. Site often for some reason, causing the cable core and the material does not correspond to crimp terminals. If this occurs should be replaced terminals. Because copper cables with copper and aluminum cable terminal or terminals with copper, are connected to the two metals in the electrochemical reaction occurs at, reduce equipment life.
29, in the absence of cable margin cases, semi-conductive layer stripping too much how to deal with?
This situation has occurred, in the event do not worry, it is timely with a semi-conductive layer recovery, reaching as far as possible consistent with the original, and accessories to ensure reliable contact with a semi-conductive layer. Absolute prohibition without any treatment, any of its natural, otherwise it will have serious consequences, specifically refer to questions 11.
30, the ground wire is not connected securely will produce what kind of results?
Will discharge and ground connections, with high-pressure electroscope test will show there is power. See question 38.
31, when the stress cone installed in the main insulation Why do the ends chamfered?
First, in order to effectively control the axial stress of the insulating end, so that it can withstand the insulating material within the allowable range; second is easy to install, to avoid scratching the inner surface of the stress cone.
32, stripping the cable semi-conductive layer is scratched main insulation measures to be taken to remedy?
Depends on the depth of scratches, If you are serious then you must redo, if only scratch the surface, can be polished smooth 40 mesh emery cloth, clean immediately after.
33, do cable cable head state of the environment when what is required? What measures should be taken to meet the requirements?
Power regulations for cable manufacture environment, there are strict requirements, American cable accessories installation must also be strictly adhered to. For safe operation of equipment we recommend that construction must avoid rain water on cable accessories, damp; winter temperature construction, pay attention to the cable warm up.
34, the tail cone sealing stress how to solve? Which method is better?
Method 1: Use insulated waterproof tape wrap, wrapped around the outside and then a layer of PVC tape.
Method 2: Make cable preset period of heat shrink tubing, cable accessories installation will reduce the stress on the tail cone, and then wrapped around a layer of PVC tape. We propose to adopt an approach.
35, T-Ⅱ head why there are two? What are the characteristics?
T - Ⅱ head there are two, one is produced by COOPER, crimp terminal with screw; Another is ELASTIMOLD produced, crimp terminals without thread. COOPER's T head can not be changed to T-Ⅱ head, T-Ⅱ T nor again the head to head, such as the need to change, it must be replaced crimp terminals, load converter casing. ELASTIMOLD's T head can be changed to T-Ⅱ head, T-Ⅱ head can also be changed to T-head. Current domestic cable accessories and more with ELASTIMOLD's T-Ⅱ head the same.
36, single-pass tube installation should pay attention to what?
Inoue installed in single-pass tube casing, do not use excessive force, otherwise it will cased hole connecting bolts twist off, twist seven and a half laps recommend appropriate.
37, T-Ⅲ head What is the role? What circumstances it will be used?
T-III head on the line to solve a number of road qualifying situation. Such as: In both installed into the line arresters, voltage transformers were installed, as well as all the way to the first two qualifying and any set of combinations. T-III head must be converted using the well casing with a load attachment.
38, why some cable head after power test using high-pressure electroscope will sound?
There exist mainly electrostatic induction. Mainly due to the generation of electrostatic induction: First semi-conductive layer overlap is not good, the second is connected to the virtual ground.