CN205157757U - Standard current transformer secondary load improves device - Google Patents

Abstract

The utility model relates to the technical field of standard quantity transmission current transformers in power systems, in particular to a secondary load improvement device for standard current transformers. The utility model connects a relative fixed load improvement device in series in the secondary circuit of the current transformer to be tested, and measures the rated value and the lower limit value by adjusting the switch of the device. The utility model simplifies the error verification process of the standard current transformer, does not need to carry a heavy current transformer load box, improves the verification efficiency, reduces the occurrence of test failures, and effectively improves the safety and reliability of the electric power operation.

Description

A Secondary Load Improvement Device of Standard Current Transformer

technical field

The utility model relates to the technical field of standard quantity transmission current transformers in power systems, in particular to a secondary load improvement device for standard current transformers.

Background technique

According to the requirements of JJG313-2010 "Verification Regulations for Current Transformers for Measurement", when performing error verification on current transformers, it is necessary to evaluate the secondary load rating and lower limit value separately. The traditional verification method is to connect a current transformer load box in series in the secondary circuit of the tested current transformer, and dial the load box to the corresponding value to measure the rated value and lower limit value. For a standard current transformer with a secondary current of 5A in the power system, the secondary rated load is generally 5VA, the light load is 2.5VA, and the load power factor is 1.0. In actual verification, only two points are needed to complete the measurement , without a complete current transformer load box.

Utility model content

In order to overcome the defects in the prior art, the utility model provides a standard current transformer secondary load improvement device, the purpose of which is to provide a current transformer load box that can replace the traditional verification, and simplify the standard current transformer error verification It is a standard current transformer secondary load improvement device that can improve the verification efficiency and reduce the occurrence of test failures.

The technical scheme that the utility model solves its technical problem adopts is:

A standard current transformer secondary load improvement device, in which a relatively fixed load improvement device is connected in series in the secondary circuit of the current transformer to be tested, and the rated value and the lower limit value are measured by adjusting the switch of the device.

The secondary terminal of the tested current transformer and the standard current transformer are respectively connected with the transformer calibrator.

A switch is also connected to the secondary circuit of the tested current transformer.

The beneficial effects of the utility model are:

The utility model simplifies the error verification process of the standard current transformer, does not need to carry a heavy current transformer load box, improves the verification efficiency, reduces the occurrence of test failures, and effectively improves the safety and reliability of the electric power operation.

Below in conjunction with accompanying drawing and specific embodiment the utility model is described in further detail.

Description of drawings

Fig. 1 is a system wiring position diagram of the present utility model;

Fig. 2 is a simplified structural diagram of the utility model.

In the picture: Load improvement device Z.

detailed description

The utility model is a standard current transformer secondary load improvement device, specifically, a relatively fixed load improvement device is connected in series in the secondary circuit of the current transformer to be tested, and the rated value and the lower limit value are determined by adjusting the switch of the device. Measurement. The load improving device Z is different from the existing current transformer load box, which does not need to be disassembled, and the error verification of the rated value and the lower limit value can be performed respectively by adjusting the switch.

In the specific implementation, as shown in Figure 1, firstly, the transformer secondary load improvement device is inserted in series into the detected transformer jack of the transformer calibrator, and the load improvement device Z can be regarded as the As a whole, then connect the secondary terminals of the standard current transformer and the tested current transformer to the transformer calibrator as shown in Figure 1.

As shown in Fig. 2, Fig. 2 is a simplified structural schematic diagram of the improved device of the present invention. It is mainly divided into two parts: resistive load and switch. Since the rated load of the standard current transformer is mostly 5VA, and the light load is mostly 2.5VA, the load power factor of the standard current transformer COSФ=1.0, for the current transformer with the secondary current of 5A, the load capacity formula S=I ² ×Z , so the total impedance is 0.2Ω at rated condition, and 0.1Ω at light load, and both light load and rated load are pure resistive loads. When measuring the rated load, turn off the switch, and the total external impedance of the load improving device Z is 0. Set the total impedance of the circuit to 0.1Ω. In this way, the conversion of the rated load and the light load is completed through the on-off of the switch. 2Ω; when measuring a light load, close the switch, which is equivalent to connecting two 0.2Ω resistors in parallel, and the total impedance of the load improving device circuit is 0.1Ω. In this way, the conversion of the rated load and the light load is completed through the on-off of the switch.

Claims (3)

1. a standard current transformer secondary load modifying device, is characterized in that: a relative dead load modifying device of connecting in tested secondary loop of mutual inductor, by carrying out the measurement of ratings and lower limit to the adjustment of device switch.

2. a kind of standard current transformer secondary load modifying device according to claim 1, is characterized in that: the secondary terminals of described tested current transformer is connected with mutual-inductor tester respectively with standard current transformer.

3. a kind of standard current transformer secondary load modifying device according to claim 1, is characterized in that: be also connected with switch in described tested secondary loop of mutual inductor.