Connection fault detection circuit of current transformer

Abstract

The invention relates to a connection fault detection circuit of a current transformer. The connection fault detection circuit comprises: a secondary transformer which is connected to a connection point I and a connection point II of outgoing lines at two ends of the current transformer; a AD converter which is connected to the secondary mutual inductor, collects the voltage signal and converts the input voltage signal into an output digital signal; an alternating current power supply which is connected to the connecting point II, wherein an auxiliary resistor R2 is connected in series betweenthe connecting point II and the secondary mutual inductor, and the two sides of the alternating current power supply are connected to the two ends of the auxiliary resistor R2; and a low-pass filterwhich is connected to the output side of the secondary mutual inductor, wherein the output side of the secondary mutual inductor is connected with the AD converter through the low-pass filter, and thefrequency of the alternating current power supply is the cut-off frequency of the low-pass filter. According to the connection fault detection circuit of the current transformer, a mode of automatically detecting an open circuit by the circuit is adopted, the efficiency is improved, the detection is timely, and hidden dangers caused by the open circuit are avoided.

Description

technical field [0001] The invention relates to the field of connection fault detection methods of current transformers, in particular to a connection fault detection circuit of current transformers. Background technique [0002] When the existing detection transformer connection fault is open, the method is to observe with the naked eye or use a multimeter to measure the connection test. This method can only troubleshoot the fault through regular maintenance or inspection, which is time-consuming and laborious, and the fault cannot be found in time. The wiring way like figure 2 As shown, the lead wire C of the current transformer A is connected to the secondary transformer through the connection node 1 and the connection node 2, and the output F of the secondary transformer enters the AD conversion, which brings great hidden dangers to the use. When the current transformer is open due to a connection fault, a high-voltage electromotive force will be generated on the second...

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Problems solved by technology

[0002] When the existing detection transformer connection fault is open, the method is to observe with the naked eye or use a multimeter to measure the connection test. This method can only troubleshoot the fault through regular maintenance or inspection, which is time-consuming and laborious, and the fault cannot be found in time. The wiring way like figure 2 As shown, the lead wire C of the current transformer A is connected to the secondary transformer through the connection node 1 and the connection node 2, and the output F of the secondary transformer enters the AD conversion, which brings great hidden dangers to the use. When the current transformer is open due to a connection fault, a high-voltage electromotive force will be generated on the secondary side of the current transformer, and at the same time, the internal magnetic core of the current transformer will be saturated, which will cause the temperature to rise, burn the current transformer, and cause a fire in severe cases

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