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A test method for zero-sequence current transformer

A zero-sequence current and test method technology, applied in the direction of instruments, measuring electricity, measuring electrical variables, etc., can solve problems such as unscientific, inability to directly give measurement data, and measure the magnitude of secondary current

Inactive Publication Date: 2011-11-30
大连互感器有限公司
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  • Abstract
  • Description
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Problems solved by technology

[0002] For a long time, in the test of zero-sequence current transformer, because the secondary current of the zero-sequence current transformer is mA level, and the internal resistance of the mA meter is greater than the secondary load value of the zero-sequence current transformer, it is impossible to use the ammeter to directly To measure the size of the secondary current, only one matching relay can be directly connected to the secondary terminal of the zero-sequence current transformer for testing, adjust the primary current to the rated value, and see if the relay operates
If the relay does not operate, then adjust the operating current of the relay. This test method can only judge whether the zero-sequence current transformer product is available, and cannot directly give measurement data. Therefore,
Such methods are extremely unscientific

Method used

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  • A test method for zero-sequence current transformer
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Embodiment

[0011] Example: Take the LJ-4 zero-sequence current transformer as an example, connect the rated load to the secondary end of the zero-sequence current transformer, its secondary impedance COSф=1; Z=10Ω, the relay setting current is 0.03A, and the protection Sensitivity 1.3A; pass current through the primary end of the zero-sequence current transformer, measure the voltage at both ends of the load with an electronic voltmeter (usually mV level), adjust the primary current, and when the reading of the electronic voltmeter is 300mV (setting current 0.3V / 10Ω =0.03A), read the primary protection current sensitivity, if the primary protection current sensitivity is less than or equal to 1.3A, it is qualified, if it is greater than 1.3A, it is unqualified.

[0012] The primary current is the current sensitivity, and the judgment of whether the zero-sequence current transformer is qualified is based on the magnitude of the current.

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Abstract

The invention relates to a zero-sequence current transformer test method, which belongs to the technical field of current transformer tests. Connect the rated load to the secondary terminal of the zero-sequence current transformer, pass the current through the primary terminal of the zero-sequence current transformer, measure the voltage (usually mV level) at both ends of the load with an electronic voltmeter, and control the voltage indication to the converted value The specified value depends on whether the primary current is qualified. The invention solves the quantification problem of the test results of the zero-sequence current transformer test, and has the advantages of scientificity, rationality and the like.

Description

technical field [0001] The invention relates to a zero-sequence current transformer test method, which belongs to the technical field of current transformer tests. Background technique [0002] For a long time, in the test of zero-sequence current transformer, because the secondary current of the zero-sequence current transformer is mA level, and the internal resistance of the mA meter is greater than the secondary load value of the zero-sequence current transformer, it is impossible to use the ammeter to directly To measure the size of the secondary current, only a matching relay can be directly connected to the secondary terminal of the zero-sequence current transformer for testing, adjust the primary current to the rated value, and see if the relay operates. If the relay does not operate, then adjust the operating current of the relay. This test method can only judge whether the zero-sequence current transformer product is available, and cannot directly give measurement d...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/00
Inventor 姜德民
Owner 大连互感器有限公司
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