The main types of faults in plastic case circuit breakers with residual earth leakage protection are operational faults, insulation problems, poor opening and closing functions and poor conduction functions. The causes of failure can be broadly divided into two categories: technical factors and operational factors; technical factors refer to defects in the product itself or in the mode of operation; operational factors refer to the faults of the operators who form these defects. The following with residual leakage protection molded case circuit breaker manufacturers from the technical factors to everyone a simple analysis of the causes of failure as residual leakage protection type case circuit breaker.

First, the operation of the failure is manifested as with residual leakage protection molded case circuit breaker dragging or false operation. Because the most basic and important function of the plastic case circuit breaker with high voltage residual leakage protection is to operate correctly and cut off the grid in time. If with residual leakage protection molded case circuit breaker dragging or fault, will cause a serious threat to the grid, mainly manifested as: First, to expand the scale of the impact of the fault, can make a circuit problems expand to the full bus, or even the entire substation, the entire plant blackout; Second, if the problem is prolonged, will affect the stable operation, intensify the degree of damage to controlled equipment; Third, the formation of non-full-phase operation, the consequences often lead to grid maintenance Operating abnormalities and vibration, thus expanding into a system failure or a large area of power outages.

The causes of operational failure are: operational organisational management defects; with residual leakage safety protection plastic case circuit breaker body research mechanical design defects; operation (manipulation) power supply technical shortcomings.

Second, with residual leakage protection molded-case circuit breaker insulation failure can be divided into internal insulation failure and external insulation failure. The damage caused by internal insulation failure is usually greater than the external insulation.

1. The main cause of internal insulation failure is casing and current transformer failure, mainly caused by water and humidity, deteriorating oil quality and lack of oil. Some main insulators also have problems with the quality of their insulation.

2. External insulation failure is firstly due to fouling and lightning strikes resulting in flashing and bursting faults with residual leakage protection plastic case circuit breakers. Dirty flash is the cause of the primary porcelain vase leakage distance school is small, not suitable for use in dirty areas; secondly, with residual leakage protection plastic case circuit breaker seepage of oil, oil leakage, so that its porcelain skirt on the simple accumulation of dirt and lead to flashover.

Third, the opening and closing function for failure is the most stringent detection of the remaining use of leakage safety protection plastic case circuit breakers. Field data calculation results show that, due to our severe opening and closing conditions, the chance of relatively small in operation, so usually with residual as well as leakage system protection plastic case circuit breaker opening and closing function analysis of the share of failure does not vary greatly. The vast majority of most students are open and close the primary cause of failure is due to with residual leakage problems protection molded case circuit breakers have obvious mechanical design defects, followed by a lack of oil or oil quality in China does not match the actual demand. There is also due to with residual leakage products protection molded case circuit breaker interrupting capacity to develop a lack of, but the former is more, due to an appropriate increase in the number of failures occurring in the division, closing small capacity, or even division, closing load working current.

In the case of residual leakage protection moulded case circuit breakers, the proportion of defective faults in the conductive function is relatively small, because: ① most of the actual load currents with residual leakage protection moulded case circuit breakers are much smaller than the rated value; ② the conductive function in the stop state is guaranteed to be simple.

Analysis of the calculated data on site faults shows that poor conductive function is first and foremost caused by mechanical faults. These include: first, poor touch, including touch surface unclean, touch size and touch pressure is not enough;. Such as copper tungsten contact fall; third, loose contact screws; fourth, soft connection breakage, etc..