A High Voltage Protection System for Secondary Current Transformer Wiring Circuit

Abstract

The invention relates to a high-voltage protection system for the wiring circuit of a secondary current transformer. The system short-circuits the protection unit, a sampling unit, a comparator, a control terminal unit, a delay reset unit and a power supply unit. The sampling unit collects The signal is transmitted to the comparator, and the comparator is respectively connected with the ground short-circuit protection unit and the control control terminal unit, and the power supply unit supplies power for the sampling control unit and the delay reset circuit. The sampling unit is equipped with a differential-mode interference protection circuit. The high-voltage CTAI signal of leakage or disconnection is connected to the ground short-circuit protection unit one way, and the other way is connected to the rectifier diode V1, and then the current is limited and lowered by the resistor R1 and the resistor R2. The voltage is divided to the comparator through the resistor R3 and the resistor R4, and the neutral point COM is connected between the resistor R1 and the resistor R2 through the differential mode interference protection filter high-voltage capacitor CV1.

Description

technical field [0001] The invention belongs to the technical fields of industrial and civil power systems, and in particular relates to a secondary current transformer wiring circuit leakage or disconnection high-voltage protection technology. Background technique [0002] When the current transformer is working normally, the secondary circuit is close to a short circuit state. At this time, the magnetomotive force F2 of the secondary winding generated by the secondary current has a demagnetizing effect on the magnetomotive force F1 of the primary winding, so the synthetic magnetic potential F0=F1-F2 is not large, and the synthetic magnetic flux φ0 is not large, and the secondary winding The value of the internally induced electromotive force E2 does not exceed tens of volts at most. Therefore, in order to reduce the size and cost of the current transformer, the section of the transformer core is designed according to the fact that the combined magnetic flux φ0 of the curr...

AI Technical Summary

Problems solved by technology

When the secondary winding is open, the induced electromotive force e2 of the secondary winding is a sharp non-sinusoidal wave, and its peak value can reach several thousand volts, which is extremely dangerous to the workers, secondary equipment and the insulation of the secondary cable.

Another effect is that due to the sharp increase of the magnetic flux in the iron core, the loss of the iron core is increased, causing severe heat and burning the current transformer

The third effect is that the error of the current transformer increases due to the excessive residual magnetism of the iron core. Open circuit operation is strictly prohibited for the secondary winding of the charged current transformer.

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