Power cable fault distance problems in testing and processing & # 65288; 3) the & # 65289;
we have learned in the content of the former two power cable accessories manufacturer in judging a problem for the power cable fault distance test, and some practical solutions. Among several key points in the first two period, we have already made solutions to some common problems and processing mode, then we will start the content of the third stage, the following let's enter below together.
( 1) High impulse voltage
in the process of impact flash method test, should not make the impact of dc high voltage is too high. Because of the impact of high dc can cause high test waveform distortion. Tested when there are more than two phase on the point of failure, may cause multiple fault point discharge at the same time, complicate the test waveforms. The impact of high dc might reduce the fault point resistance high too fast, even to gold ground fault attribute, thus bring trouble to fixed work.
based on the above three reasons, impact flash method test cable fault, impact of dc high voltage should be changed from low to high gradually, and can make the fault point can be fully discharge.
( 2) Fault cable seriously be affected with damp be affected with damp
in the actual test of cable fault, sometimes encountered this kind of circumstance: fault cable leakage current is very big, don't add the dc high voltage to use flash method. When impact flash method is used to test the voice of the breakdown discharge gap and impact current ball from the numerical point of view, can determine fault point has been ionization breakdown, but flash instrument does not show the discharge waveform. Caused this kind of phenomenon is the main reason of the fault can be affected with damp be affected with damp.
when cable fault parts of large area be affected with damp be affected with damp, due to the fault point discharge area is large, long distance, energy concentration, arc form instantaneous short circuit is not enough to make the point of failure, so can't form the ideal discharge waveform. Be affected with damp be affected with damp serious fault cable, though cannot be measured relatively ideal waveform, often near the fault parts, clear discharge can be heard, it is highly advantageous point of failure. In addition, be affected with damp be affected with damp of the serious fault, after a long time impact discharge and fever, when to stop impact discharge and cooling, will further absorption of moisture, Water) , which often make a significant reduction in the fault resistance, can reduce even become low resistance fault.
that's problems and processing of power cable fault distance test ( The third phase) The entire contents of the introduced, more about power cable accessories manufacturer in judging power cable fault distance when testing the problem and some practical solutions, please continue to pay attention to AnWei electric power company. Consultation telephone: 0558 - 5026182