A Parallel Arc Suppression Coil Automatic Compensation Device

Abstract

Disclosed in the invention is a parallel type automatic compensation apparatus for an arc-suppression coil. The automatic compensation apparatus is composed of a Z type transformer, an arc-suppression coil, a damping resistor, capacitance regulating units, inductance regulating units, a line selection resistor, silicon controlled rectifier switches, and a microcomputer controller. When a single-phase ground fault occurs at a system, the ground capacitance current of the system can be compensated rapidly; and the line selection function is realized. Meanwhile, the compensation capacity of the arc-suppression coil can be adjusted in real time according to the change of the ground capacitance current of the system; and no heavy closing inrush current is generated when capacitor switching is carried out, thereby avoiding the adverse effect on the capacitor. Besides, the heavy inductive current can be provided by using the small-capacity inductor, thereby lowering the cost and reducing the occupied area. Moreover, the capacitors and inductors are connected in parallel to a secondary winding of the arc-suppression coil, so that the regulating range of the arc-suppression coil can be increased and easy capacity expanding can be realized. Therefore, the automatic compensation apparatus has advantages of wide regulating range, high capacity expanding, fast compensation speed, improved power supply safety and reliability of the power distribution network, and high practicability.

Description

technical field [0001] The patent of the present invention relates to the field of power system protection, in particular to an automatic compensation device for an arc-suppressing coil that quickly compensates the capacitive current of the system and can automatically track and adjust the compensation current while correctly selecting the grounding line. Background technique [0002] At present, in my country's power system, the distribution network of 110KV and below, especially the 35KV distribution network system, mostly adopts the neutral point grounding method through the arc suppression coil. When a single-phase ground fault occurs, the inductance current flowing through the arc suppression coil can compensate the ground capacitance current of the power grid and reduce the ground point current, thereby avoiding the occurrence of arc, and can suppress the occurrence of ferromagnetic resonance, improving the reliability of power supply of the system sex. The arc suppre...

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Problems solved by technology

[0003] In actual work, since the neutral point potential of the distribution network is not zero, the turn-adjusting arc suppressing coil often undergoes series resonance with the ground capacitance during normal operation, causing the damping resistor to withstand a high voltage, which is easy to cause The damping resistor is damaged, and when the switch connected in parallel with the damping resistor refuses to move, the neutral point displacement voltage is likely to further increase due to series resonance, resulting in unstable operation of the system

In addition, with the continuous expansion of the scale of my country's power grid and the change of the operation mode of the power system, the traditional turn-adjusting arc suppression coil can only work in the pre-adjustment mode, resulting in the inability of the turn-adjusting arc suppression coil to realize the capacitive current to the ground. Real-time measurement and tracking compensation, cannot effectively eliminate the arc at the grounding point

[0004] However, the capacity-adjusting arc suppressing coil, as a follow-up type, has no damping resistance, which is prone to series resonance phenomenon and acts as a secondary switching capacitor when a ground fault occurs. The capacitor will have a large impact, and the inrush current will have an adverse effect on the capacitor.

At the same time, since the capacity-adjusting arc suppressing coil is far away from the compensation position during normal operation, after a single-phase ground fault occurs, then adjusting the arc suppressing coil to the compensation position requires a large capacitance current, so the capacitance value of the parallel connection of the secondary side must be relatively large. Large, and it takes at least 60ms to adjust to the full compensation position, the speed is slow, the effect is poor, and ferromagnetic resonance may occur

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