Control device for line inrush current

Abstract

The invention relates to a control device for line inrush current. The control device comprises a casing, wherein a nameplate instruction and a dial switch are arranged above a boss on the front sideof the casing; the dial switch is connected with a circuit board inside the casing through a wire; mounting boards are arranged at the upper end and the lower end of the casing. When a circuit breakeris closed or a power grid is in a working state and exciting current is formed on a line, the control device for the line inrush current can detect line current, delay tripping control and prevent maloperation tripping of the circuit breaker by excitation. By adopting a microcontroller technology, when current exceeds setting current with a set multiple, current properties are immediately judged,and instantaneous over-current protection is performed, and delay duration can be set according to the requirements.

Description

technical field [0001] The invention relates to the technical field of power transmission and distribution, in particular to a line surge current control device matched with a high-voltage circuit breaker. Background technique [0002] In order to achieve long-term uninterrupted power supply, it is necessary to continuously improve the power system and enhance the power supply quality and efficiency of the power system. At the same time, when encountering a fault, the power supply system with a high degree of intelligence can identify the fault as soon as possible and take corresponding protection measures to further protect the equipment. The protection equipment in this power supply system avoids greater losses caused by failures, and develops work efficiency and maintenance costs in the best direction. Nowadays, the development of electronic industry technology is in full swing. Lido large overvoltage transformer was developed and put into production. However, in contr...

AI Technical Summary

Problems solved by technology

However, if the two situations mentioned above occur, the excitation inrush current increases instantaneously, resulting in a transient process with a duration of several cycles. At this time, the excitation inrush current has little correlation with the short-circuit current.

At the same time, during operation, short-term overload and overvoltage of the transformer occur from time to time

These multiple minor faults and a large number of transient processes will increase the probability of transformer damage

[0006] However, the existing inrush controller installation method often adopts the following two principles, among which the second harmonic braking principle has the following problems: 1. The braking ratio is difficult; 2. It may not be possible to identify the symmetrical inrush current; 3. Modern transformers The change of magnetic lift characteristics reduces the second harmonic content during inrush current, and the protection is prone to malfunction

[0007] Using the discontinuity angle principle to judge will also face some problems: 1. Higher sampling rate is required, so the hardware requirements are higher; 2. Certain measures need to be taken to measure the discontinuity angle after CT saturation

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