CN202975222U - Integrated tester for secondary circuit of current transformer - Google Patents

Abstract

A current transformer secondary circuit comprehensive tester, belonging to the field of testing technology, its technical proposal is: it includes a battery pack, a flow test circuit and a point polarity test circuit, the flow test circuit includes an inverter, an AC An ammeter, a flow test switch and a current limiting resistor, the DC input end of the inverter is connected to the battery pack through the flow test switch, and the AC current output from the AC side is injected into the current transformer under test through the AC ammeter and the current limiting resistor. secondary loop. The utility model has complete functions, simple operation, light weight, is easy to carry and manage, can greatly reduce the labor intensity of test personnel, and improve the work efficiency of the current transformer test.

Description

Current Transformer Secondary Circuit Comprehensive Tester

technical field

The utility model relates to a device for conducting a point polarity test and a secondary circuit flow test on a current transformer, which belongs to the technical field of testing.

Background technique

The current transformer secondary circuit current test is to use an external power supply to pass a set current in the secondary circuit of the current transformer (see Figure 1), and then compare whether the current collected by the protection device is consistent with the current passed in. And use this to verify whether the secondary circuit wiring of the transformer is correct, that is, whether there is an open circuit, shunt or phase sequence error in the terminal box 1 in FIG. 1 . The point polarity test is to use the battery to pass DC current in the primary winding of the current transformer for a short time (see Figure 2), and at the same time observe the deflection of the ammeter pointer in the secondary circuit to judge the polarity of the secondary winding. Although the above two tests are often carried out at the same time, the test devices used in the two tests are independent of each other, which increases the types of test instruments and brings inconvenience to the carrying, storage and management of the instruments.

At present, the instrument used in the current transformer secondary circuit current test is the relay protection tester. Although this instrument has high test accuracy (far exceeds the accuracy requirements of the general current test), its weight is too large (nearly 40Kg) and needs to be connected to the maintenance power supply, which greatly increases the labor intensity of the test personnel and reduces the work efficiency of the flow test. In addition, the existing point polarity test method only connects the ammeter to the secondary circuit of the current transformer. The secondary circuit is not conducive to the rapid elimination of faults.

Contents of the invention

The purpose of this utility model is to overcome the deficiencies of the prior art and provide a portable current transformer secondary circuit comprehensive tester to reduce the labor intensity of testers and improve the working efficiency of current transformer tests.

The purpose of this utility model is realized with following technical scheme:

A current transformer secondary circuit comprehensive tester, comprising a battery pack, a current flow test circuit and a point polarity test circuit, the current flow test circuit includes an inverter, an AC ammeter, a current flow test switch and a current limiting The DC input terminal of the inverter is connected to the battery pack through the current test switch, and the AC current output from the AC side is injected into the secondary circuit of the current transformer under test through the AC ammeter and the current limiting resistor.

The above-mentioned current transformer secondary circuit comprehensive tester, the point polarity test circuit includes a primary side DC ammeter, a point polarity test switch and a secondary side DC ammeter, the primary side DC ammeter and the primary winding string of the current transformer under test After connecting, connect the output voltage of the battery pack through the polarity test switch, and connect the two ends of the secondary side DC ammeter to the two ends of the secondary winding of the current transformer under test respectively.

The utility model integrates the through-current test circuit and the point polarity test circuit, and both test circuits are powered by a battery pack, which not only reduces the types of current transformer test instruments, but also greatly reduces the weight of the test instruments. In addition, the tester does not need to be connected to the maintenance power supply, which simplifies the test operation and saves test time. Two ammeters are set in the point polarity test circuit, which is helpful for the test personnel to quickly find the line fault.

The utility model has complete functions, simple operation, light weight, is easy to carry and manage, can greatly reduce the labor intensity of test personnel, and improve the work efficiency of the current transformer test.

Description of drawings

Below in conjunction with accompanying drawing, the utility model is described in further detail.

Figure 1 is a schematic diagram of the current transformer secondary circuit flow test;

Figure 2 is a schematic diagram of point polarity test;

Fig. 3 is the electrical schematic diagram of the utility model.

The labels in the figure are: 1, terminal box; 2, protection device; CT, current transformer; DC/AC, inverter; e, AC power supply; B, battery pack; A0, ammeter inside the protection device; A1, AC ammeter; A2, secondary side DC ammeter; A3, primary side DC ammeter; R, current limiting resistor; K1, flow test switch; K2, point polarity test switch.

Detailed ways

Referring to Fig. 3, the utility model is composed of a battery pack B, an inverter DC/AC, an AC ammeter A1, a primary side DC ammeter A3, a secondary side DC ammeter A2 and a current limiting resistor R. Inverter DC/AC, AC ammeter A1 and current limiting resistor R form a flow test circuit, and the primary side DC ammeter A3 and secondary side DC ammeter A2 form a point polarity test circuit. Both test circuits are powered by battery pack B.

The inverter DC/AC outputs 10V AC voltage, and the resistance value of the current-limiting resistor R is 10 ohms, so that the current is limited to about 1A. When carrying out the flow test, disconnect the measured current transformer CT from the terminal box 1, and connect the flow test circuit to the terminal box of the current transformer in the terminal box 1 (connect the flow test circuit in series with the terminal box of the current transformer CT In the secondary circuit), close the flow test switch K1, and compare the measured values of the ammeter A0 and the AC ammeter A1 in the protection device to complete the flow work.

When conducting the point polarity test, connect the secondary side DC ammeter A2, the primary side DC ammeter A3, the point polarity test switch K2 and the measured current transformer CT according to Figure 3, and close the point polarity test switch K2 for a short time. Determine the polarity of the secondary winding by observing the deflection direction of the pointer of the secondary side DC ammeter A2. If the pointer of the secondary side DC ammeter A2 does not deflect, but the pointer of the primary side DC ammeter A3 deflects, it means that there is an open circuit fault in the secondary circuit. If the pointer of the primary side DC ammeter A3 does not deflect, it means that the fault is in the primary circuit of the current transformer.

Claims (2)

1. A current transformer secondary circuit comprehensive tester is characterized in that it includes a battery pack (B), a flow test circuit and a point polarity test circuit, and the flow test circuit includes an inverter (DC/ AC), AC ammeter (A1), flow test switch (K1) and current limiting resistor (R), the DC input terminal of the inverter (DC/AC) is connected to the battery pack ( B), the AC current output from the AC side is injected into the secondary circuit of the current transformer under test through the AC ammeter (A1) and the current limiting resistor (R). 2. The current transformer secondary circuit comprehensive tester according to claim 1, wherein the point polarity test circuit includes a primary side DC ammeter (A3), a point polarity test switch (K2) and a secondary side DC ammeter (A2), the primary side DC ammeter (A3) is connected in series with the primary winding of the current transformer (CT) to be tested, and then connected to the output voltage of the battery pack (B) through the point polarity test switch (K2), the secondary side The two ends of the DC ammeter (A2) are respectively connected to the two ends of the secondary winding of the measured current transformer (CT).

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