Instantaneous short-circuit current protection method and device

Abstract

The invention discloses an instantaneous short-circuit current protection method, which comprises the following steps of: sampling instantaneous current of a protected circuit in real time, and selecting a corresponding protection method according to a relationship between an instantaneous current sampling value and a preset current threshold: if the instantaneous current sampling value is greater than the current threshold, performing protection by using a peak value method, otherwise, performing protection by using a peak value method; and protecting by using an effective value method. The invention further discloses an instantaneous short-circuit current protection device. Compared with the prior art, the peak value method which is high in timeliness but insufficient in accuracy and the effective value protection method which is high in accuracy but insufficient in timeliness are organically combined, the protection scheme which needs to be adopted currently is judged based on the instantaneous current sampling value, and rapid protection is carried out by adopting the peak value method under the condition that the instantaneous current is too large. The system safety is improved, an effective value type protection method is adopted under the condition that the instantaneous current is small, the protection accuracy is improved under the condition that the system safety is guaranteed, and the system protection requirement can be better met.

Description

technical field [0001] The invention relates to an instantaneous current protection method. Background technique [0002] As an important component in the power distribution system, the low-voltage circuit breaker undertakes the important task of protecting the power distribution network and electrical equipment from faults such as overload, short circuit and leakage. Among them, if the instantaneous short-circuit fault is not cut off in time, it will greatly affect the smooth operation of the power grid, and even cause equipment damage and fire in severe cases. The traditional instantaneous protection methods of circuit breakers generally include peak value method, effective value method and so on. Among them, the peak value method has strong timeliness, but it is easily interfered by non-periodic component attenuation components, and its accuracy is insufficient; the effective value method has good accuracy, but the judgment requires a power frequency cycle, and the timel...

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Problems solved by technology

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an instantaneous short-circuit current protection method, which combines the peak value method with strong timeliness but insufficient accuracy and the effective value type protection method with strong accuracy but insufficient timeliness. combined to better meet the protection needs of the system

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