Short circuit and open circuit state detection circuit for secondary side winding of current transformer

Abstract

The invention discloses a short circuit and open circuit state detection circuit for a secondary side winding of a current transformer. The circuit can output voltage which accurately reflects that the secondary side winding of the current transformer is in short circuit, open circuit, or a normal state, so as to determine the short circuit, open circuit, or normal state of the secondary side winding of the current transformer. The short circuit and open circuit state detection circuit for a secondary side winding of a current transformer comprises a signal sampling circuit, a secondary side winding state judgement circuit, and a constant current source circuit used to provide constant current. The signal sampling circuit comprises sampling resistors connected in parallel with the secondary side winding of the current transformer, a plurality of diodes are connected in series, and the anode of the diodes is connected with the first end of the sampling resistor, and the cathode is connected with ground. The output end of the constant current source circuit is connected with the second end of the sampling resistor, so as to provide operating voltage for the signal sampling circuit. Voltage on two ends of the sampling resistors outputs a voltage signal through the secondary side winding state judgement circuit.

Description

technical field [0001] The invention relates to a circuit design for detecting the short-circuit and open-circuit state of the secondary side of a current transformer, in particular to a circuit design for detecting the short-circuit and open-circuit state of the secondary side of the current transformer with low cost, high accuracy and high efficiency. Background technique [0002] A current transformer (CT for short) can convert a primary current with a large value into a secondary current with a small value through a certain transformation ratio. Therefore, in many occasions where large currents are applied, CTs are required to realize functions such as protection and measurement. A large part of the CT wiring methods are connected in the form of connecting wires. In this connection mode, fault conditions such as short circuit and open circuit of the secondary winding of the CT may occur. On the one hand, these failures will lead to abnormal measurement of the measureme...

AI Technical Summary

Problems solved by technology

This method is quite cumbersome both from the perspective of hardware and software, and it is not cost-effective in terms of cost and development progress.

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