Technical causes of Schneider low-voltage circuit breaker accidents

(1) Operational failure

Operation failure is manifested by the dragging or misoperation of the circuit breaker. Because the fundamental and important function of the high-voltage circuit breaker is to act correctly and quickly remove the fault of the power grid. If the circuit breaker is dragged or maloperated, it will pose a serious threat to the power grid, first of all: (1) expanding the scope of the incident, which may expand the power outage of the entire bus and even the whole plant as long as only one circuit fault occurs; (2) If the time of fault removal is prolonged, it will affect the operation stability of the system and aggravate the damage degree of the controlled equipment; (3) The formation of non-full phase operation. As a result, it often leads to abnormal operation and vibration of power grid maintenance, which can easily expand into system incidents or large-scale power outages.

The top causes of operation failure are:

(1) Defects of operating mechanism;

(2) Mechanical defects of the circuit breaker body;

(3) Defects of operation (control) power supply.

Technical causes of Schneider low-voltage circuit breaker accidents

Technical causes of Schneider low-voltage circuit breaker accidents

(2) Insulation incidents

The circuit breaker insulation incident can be divided into the internal insulation terminal and the external insulation incident. The hazards caused by internal insulation incidents are usually greater than those of external insulation.

1. Internal insulation

The internal insulation end mainly has the casing and current transformer incident, and the main reason is that the water is damp; This is followed by deterioration of oil quality and lack of oil quantity.

2. External insulation

The external insulation incident is mainly due to the flashover of the circuit breaker and the explosion caused by pollution flashover and lightning strike. The main reason for the dirt flash is that the leakage distance of the porcelain bottle is small, which is not suitable for use in the dirty area; The second is the oil leakage and leakage of the circuit breaker, which makes it easy to accumulate dirt on the porcelain skirt and cause flashover.

(3) Breaking and closing functional incidents

The breaking and closing task is a strict inspection of the circuit breaker. The primary reason for the vast majority of breaking and closing incidents is that the circuit breaker has significant mechanical shortcomings, followed by lack of oil or oil quality that does not meet the requirements. It is also due to the lack of circuit breaker breaking ability. However, there are many of the former, because a considerable number of incidents occur in the small capacity of the division and combination, and even the distribution and combination of load current.

(4) Incidents of poor conductive function

The analysis of on-site incident statistics shows that the defective conductive function is mainly caused by mechanical shortcomings. Among them: (1) poor contact. Including unclean contact surface, contact size and lack of contact pressure; (2) Dropping and jamming. Such as copper-tungsten contacts dropping, etc.; (3) The contact screw is loose; (4) Soft connection breakage, etc.

Technical causes of Schneider low-voltage circuit breaker accidents

Sections viewed

Contact

working hours