SU433433A1 - METHOD FOR DETERMINING ERRORS OF THE TRANSFUDER CURRENT IN TRANSITION MODE - Google Patents

Description

The invention relates to a measurement technique and can be used in determining the errors of a current transformer in a transient mode.

A known method for determining the error of a current transformer in a transient mode is put by these oscillograms of the primary and secondary currents,.

However, the implementation of transients with large values of primary currents and constant time of the primary circuit is difficult. In addition, the results in this case are obtained in the form of oscillograms that are difficult to decipher.

To simplify the method, the calculated value of the periodic component of the primary current is set from the current source of operating frequency, and the calculated value of the instantaneous aperiodic magnetization current of the current transformer | from the direct current source.

The method is based on the independence of the aperiodic transient process in a nonlinear current current transformer, caused by the 5 aperiodic component of the primary current on the one hand, and determining the dependence of the transfer of the periodic component of the primary current on the value of the periodic field voltage in the other.

The drawing is a diagram of the device that implements the proposed

5 way

The device contains a current transformer 1, a primary 2 and a secondary 3 windings of a current transformer, DC sources

0 4 and current operating frequency 5, resistors 6 and 7, chokes 8 and 9, shun ° you 10 and And, voltmeter 12, ammeter 13, switch 14.

The primary winding of the current transformer is connected to a regulated current source operating

frequency 5, and the secondary to the DC source 4. The inductance in the DC circuit is chosen such that it forms a sufficiently large inductive resistance for the AC current, and the resistance, given the condition of the specified DC value,

The resistor and choke in the secondary winding pees provide the specified resistance of the branch of the secondary current transformer.

The primary and secondary current transformer circuits include shunts 10 and II, selected so that their nominal currents are treated as numbers of turns of the secondary and primary windings, and the nominal output voltages are equal.

The circuit provides for a voltmet 12 of a selective type, acting, intermediate or average, (depending on the error to be determined), which is connected via a switch to the output of the shunts. Three switch positions allow measurement of the primary and secondary currents and the magnetizing current.

The ammeter 13 serves to control the direct current of the bias.

If the direct current is set equal to the aperiodic current of the initial circuit current in the secondary winding

the transient moment and the periwick moment equal to the given primary current of the operating frequency of the transient under study, then voltmeter 12 will show the values of voltages proportional to the primary current, magnetizing current and minus direct current to the secondary tone.

Knowledge of these currents allows us to determine the error of the current transformer at a given point in time of the transient under study.

Determining the current transformer errors in the transient mode by the current method does not require any auxiliary windings to be performed on the current transfer system, therefore there is no need to disassemble the current transformer.

PRIVACY INVENTIONS

The method of determining the current transformer errors in the transient mode by the value of the periodic component of the primary and secondary current, characterized in that, for the purpose of simplification, the calculated value of the periodic component of the primary current is set from the current source of operating frequency,. and the calculated value of the instantaneous aperiodic current is magnetized-i nor the current transformer from a direct current source.