Power transmission and distribution system of leakage for earth capicitance storage charge and system control method

Abstract

This invention relates to a transmission and distribution system releasing earth capacitor storage charges and a system control method characterizing in setting a releasing transformer in the system, in which, the three phase winding of the secondary side is connected end to end in series, an open-end is set between any adjacent two windings to form a releasing channel by bridging resistor elements at the two ends of the open-end or short-connecting the open-end directly to form a triangle connection of the secondary side, which provides a releasing channel to charges stored to the earth capacitor when the earth system of small current is faulty in earth to prevent from generating over voltage and ferro-resoanace induced in the resuming process of the earth voltage of the faulty phase and sanity phase.

Description

Technical field: [0001] The invention relates to a protection system and a protection method for a small current grounding system. Background technique: [0002] There are two types of arc suppression methods for small current grounding systems, or neutral point ungrounded systems, one is neutral point arc suppression, such as the arc suppression method in which the neutral point is grounded through an arc suppression coil; the other type is the neutral point arc suppression method. It is fault phase arc suppression. The fault phase arc suppression method means that when a single-phase grounding occurs in a small current grounding system, the fault phase is directly grounded through switching elements such as contactors and thyristors, or the impedance is put in between the fault phase and the ground. between, implement arc suppression. [0003] There are two types of single-phase grounding for small current grounding systems, permanent grounding and non-permanent grounding...

AI Technical Summary

Problems solved by technology

[0005] In the above fault phase arc suppression method, at the moment when the fault phase is grounded in order to judge whether it is an instantaneous fault or to remove the fault, the electric charge will be stored on the capacitance of the system to ground. After the faulty phase, overvoltage occurs during the recovery process of the healthy phase-to-ground voltage, and the power frequency overvoltage of the faulty phase-to-ground can be up to 2 times, which may damage the system insulation and cause accidents; on the other hand, because the neutral point is not grounded, this The stored charge cannot be discharged, only through the voltage transformer, which may cause the saturation of the voltage transformer and ferromagnetic resonance, endangering the safe operation of the system

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