Protection method for adaptive instantaneous current quick tripping

Abstract

The invention provides a protection method for adaptive instantaneous current quick tripping. The method comprises: a current current value of a power supply line is read; a current value, read at last time, of the power supply line is subtracted from the read current current value of the power supply line to obtain a fault current component; according to the fault current component, whether starting of a sudden change of a current occurs is determined; a fault type is determined; whether a practically measured current is larger than a short-current calculation value at the tail end of the line is determined; and a tripping signal is sent and the like. The method has the following effects: although the short-circuit current at the tail end of the line and the short-circuit current at any point of the line change simultaneously with the change of the reactance of the system, the short-circuit current at any point of the line is larger than or equal to the short-circuit current at the tail end of the line all the time. On the basis of the adaptive change, the sensitivity of the protection device is improved; and the complete protection range of the overall line is realized. The protection device can cut off the fault instantaneously. Compared with the traditional instantaneous current quick-tripping way, the provided method enables protection to be improved essentially.

Description

technical field [0001] The invention belongs to the technical field of power line protection, in particular to a protection method for self-adaptive instantaneous current breaking. Background technique [0002] In the power system, the setting value of the traditional instantaneous current quick-break protection should be matched with the next-level quick-break current. Since it has no time limit, the setting value of the current quick-break protection should be staggered. Under the maximum operation mode, the three-phase short circuit at the outlet of the adjacent line The current flowing through the place where the protective device is installed. When it is not in the maximum operation mode or the minimum operation mode, the protected range will become smaller, and the protection range may even be zero. The protection range of instantaneous current quick break is greatly affected by the system operation mode, which is a very serious defect. [0003] figure 1 It is an el...

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Problems solved by technology

[0013] It can be seen from the calculation results that in order to stagger the short-circuit current at the B bus in the maximum operation mode, the protection setting value needs to be greater than 1643A (three-phase short circuit) and 1429A (two-phase short circuit), while the short-circuit current at the B bus in the minimum operation mode is far is less than the above value, so it will be difficult for the current quick-break protection device to act effectively in the minimum operating mode of the system

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