Air Heat Pump,Evi Air Source Heat Pump,Evi 85°C Heat Pump,Evi Heat Pump Air To Water Guangdong Shunde O.S.B. Environmental Technology CO.,LTD. , https://www.heatpump-osb.com
The common types of street lamp low-voltage cable faults can be divided into open faults with leakage to the soil and closed faults with no leakage to the soil.
2. According to the location of the fault point, it can be divided into failure of the cable body, inside the lamp post, under the lamp post, in the inspection well, and at the joint.
According to the nature of cable faults are divided into:
(1) Open circuit: It is caused by long-time high-current burnout or excavation by external force. The phase line and neutral line are disconnected, and normal power transmission can sometimes be performed but some of the streetlights are not bright. This type of fault is the most common type of street light cable fault and is easier to solve.
(2) Short circuit: often shows a short circuit between the zero line and the phase line or between the phase line and the phase line. It is due to the instantaneous high-current sintering, which cannot be normally transmitted at this time. Short-circuit faults are better resolved if the skin is broken, and failures where the skin is not damaged are more difficult to resolve.
(3) Poor insulation: The power can be transmitted for a short time, but the current in the line is abnormal. After a period of time, the circuit breaker protection action is called “soft failureâ€. The cable is damaged or the insulation is aging. This type of fault is the difficulty of our test.
The main reasons for the failure of street lamp low-voltage cable 1. External damage Due to the non-standard and arbitrariness of road construction and other pipeline construction, it often happens that the street lamp cable is cut out and damaged. Moreover, most of the construction units are after digging out the street lamp cable. , Not to inform the street lamp management department to re-bury it privately, and the resulting cable damage will result in complete destruction of the cable after a period of operation.
2. Long-term over-load operation of cables Due to lack of design, the lack of “double weight†of the cable size, unbalanced three-phase load, and arbitrarily increasing the load, the long-term overload operation of some cables leads to the temperature of the cable. Increasing, especially during hot summer days, the temperature rise of the cable often leads to weaker cables and the first breakdown at the joints. In summer, the reason for the high rate of cable failures is just this.
3. The construction quality of the cable is unsatisfactory and savage construction. If the cable is illegally dragged, it will cause damage to the cable sheath. After several months or even years, the moisture will infiltrate, and the insulation will be reduced to cause complete failure of the damage. In addition, cable joints are the weakest link in the cable route. During the process of making cable joints, if the joints are not tightly crimped, loosely packed, and poor heat shrinkage, etc., the insulation of the cable joints will be reduced, causing The fault occurred.
Dear Customer:
Thank you for your attention to our products. In addition to this product introduction, the company also has insulation ladders, high-voltage insulation mats, cable fault testers, high-voltage measuring instruments, insulation boots gloves pressure test equipment, power safety equipment cabinets, etc. Introduction, if you are interested in our products, welcome to inquire. Thank you!
The cable fault tester manufacturer talks about the type and main reason of the low voltage cable fault
Cable fault tester manufacturers to talk about the type of low voltage cable and the main cause of failure of the power cable fault search method commonly used power cable fault search is generally divided into fault diagnosis, fault location, path detection, fault fixed point and other four steps. Fault location methods mainly include: First, the bridge method, which mainly includes the traditional DC bridge method, voltage drop comparison method, and DC resistance method; and secondly, low-voltage pulse method, also known as radar method, is passed through the instrument at one end of the cable. A low-voltage pulse signal is input to the cable. When a fault point with an impedance mismatch is encountered, the pulse signal is reflected and returned to the measuring instrument. This method has the advantages of simple operation and high test accuracy. It is mainly used to test the breakage and low resistance faults, but it cannot test high resistance faults and flashover faults; the third is the pulse voltage method, and DC voltage must be applied to the faulty cable. Signal; four is the pulse current method, the need to apply DC high-voltage signal to the fault cable; five is the second pulse method.