SU1322212A1 - Device for measuring errors of current transformers - Google Patents

Abstract

A device for measuring the error of current transformers (T) contains an alternating current source 1, current sensors 2, 6, tracking unit (B) 3, incremental and load resistance 4 and 5, B 7 registration and terminals 8 for connecting the tested T. Invention expands the functionality of the device and improves the accuracy of measuring the errors T of the current. 1 na. L tv5

Description

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The invention relates to electrical measuring equipment and can be used to measure errors of current transformers.

The purpose of the invention is to enhance the functionality and increase the accuracy of measurement of current transformer errors.

The drawing shows a block diagram of a device for measuring the errors of current transformers.

The device contains an AC source 1, a first current sensor 2, a tracking unit 3, an additional 4 and a load 5 resistance, a second current sensor 6, a recording unit 7 and terminals 8 for connecting a current transformer under test, the first output of the AC source 1 being connected via an input the first current sensor 2 to the first terminal 8 of the secondary winding of the test current transformer, the second through the tracking unit 3 to the second terminal 8 of the secondary winding of the test current transformer and through series-connected additional 4 and the load 5 resistance and the input of the second current sensor 6 to the first terminal of the secondary winding, the inputs of the registration unit 7 are connected to the outputs of the first 2 and second 6 current sensors, the common point of the tracking unit 3 is connected to the common point of the additional 4 and load 5 resistances.

The device works as follows.

AC source 1 generates a current equal to the primary current brought to the secondary side of the current transformer

it i. Wj

V,

where i is the primary current given

to the secondary side; w, w. - the number of turns of the primary and secondary windings, respectively. Voltage from additional resistance 4, determined by dissipation inductance and active resistance of the test subject's secondary winding

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current transformer fed to the input of the tracking unit 3

and

SC (P) i (P) 7. (P),

where Up is the voltage on the tracking unit 3; z - resistance at incremental

D. resistance

The output voltage of the tracking unit 3 is applied between the second terminal of the secondary winding and the common point. The tracking unit 3 amplifies the current input signal and ensures that the input and output signals are equal in voltage.

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(5 20 25

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40

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Thus, currents corresponding to the secondary current and the magnetizing current in direct tests flow through the resistance of the load and the secondary winding. The values of the currents of the source and the load from the current sensors arrive at block 7 of registration.

Claims (1)

Invention Formula A device for measuring the errors of current transformers containing an alternating current source connected by the first output through the first current sensor to the first terminal of the secondary winding of the current transformer under test, the primary winding of which is open, the second output through the series-connected additional and load resistance and the second current sensor to the first the secondary terminal of the test current transformer, and the outputs of the first and second current sensors are connected to the registration unit, different, that, in order to expand the functionality and increase the measurement accuracy, a tracking block was inserted into it, the common point of which is connected to the common point of the additional and load resistances, the input is connected to the first output of the AC source, and the output to the second terminal of the secondary winding of the transformer under test are currents .