Views:198 Author:Site Editor Publish Time: 2020-12-10 Origin:Site
Today, we will discuss the causes of common faults of 10kV overhead lines and equipment.
The fault range is at the upper end of the line, which is caused by a three-phase cable short circuit or two-phase cable short circuit. The main reasons include electric wire short circuit and oil injection of oil-filled equipment (such as oil circuit breaker, power capacitor, transformer), bird's nest hazard in spring, thunder and lightning in the rainy season, rainstorm, theft and damage of poles and cables, felling trees to hit wires and other natural disasters or human factors.
The fault range is at the lower end of the line, which is caused by the sudden increase of electrical load beyond the setting value of line protection or three-phase or two-phase short-circuit. The reasons are basically the same as above. Quick breaks and over currents are easy to find because the fault range is small and the fault causes are clear. We can rely on automated cable fault indicators and reliable electric wire fault indicators.
This kind of fault can occur in the whole line, which can be divided into permanent grounding and instantaneous grounding. The main reasons are broken wire, insulator breakdown, trees under the line and other reasons leading to multi-point leakage. Due to the large range of ground faults, the cause of the fault is not obvious. Sometimes it is necessary to determine the cause of the fault with the help of instruments, such as digital overhead line fault passage indicators and advanced overhead line fault indicators.
In general, the line tripping and reclosing are successful, which indicates that the fault is a transient fault, such as bird damage, lightning stroke, strong wind, etc. If the reclosing is not successful, then the fault is a permanent fault, such as pole down, broken line, mixed line, etc.
If it is a current quick break trip, the fault point is usually in the front section of the line. If it is an over-current trip, the fault point is usually in the back section of the line. If the over-current and quick break trip at the same time, the fault point is generally in the middle of the line.
In addition to the key inspection of the general fault range, other sections should also be inspected to avoid missing fault points and prolong the accident handling time. We can also use some instruments to help us find fault points, such as reliable overhead line fault indicators and accurate electric wire fault passage indicators.
A point of line phase to ground insulation loss, the phase current through this point into the earth, this is called single-phase grounding. The ground fault of rural 10 kV power grid accounts for about 70% of 10 kV line ground faults. Single-phase grounding is the most common fault in electrical faults. Its harm mainly lies in the destruction of the three-phase balance system. The voltage of the non-fault phase increases to the original radio three times, which may cause damage to the insulation of the non-fault phase.
Chaobo automatic technology provides you with safety earthing and short-circuit kits and indicator digital monitors to help you better monitor and maintain overhead lines.