RU2282207C1 - Device for calibrating direct high-voltage dividers - Google Patents

Abstract

FIELD: measuring technique.

SUBSTANCE: device comprises direct high-voltage divider, reference composed direct voltage divider made on the basis of resistive elements, and two-row voltage comparator. The reference composed direct voltage divider has high-voltage arm composed of three nominally equal closed resistive elements and output arm for permitting alternative switching-off of the resistive elements of the high-voltage arm and change of conversion factor of the divider .

EFFECT: simplified design.

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Description

The present invention relates to electrical engineering and is intended for calibration of high voltage DC dividers in a wide range of measured values.

A device for calibrating high-voltage dividers of constant voltage, containing a calibrated high-voltage divider of constant voltage with the ability to close part of its resistive elements, an auxiliary divider of constant voltage in the form of a multi-decade low-voltage divider of constant voltage and an additional resistor to the operating voltage connected in parallel with the calibrated divider, and a zero indicator [ one].

A disadvantage of the known device lies in the complexity of manufacturing a multi-decade high-precision low-voltage constant voltage divider, as well as the need to close part of the resistive elements of a calibrated high-voltage constant-voltage divider, which is not always ensured by its design.

Of the known closest in technical essence is a device for calibrating high voltage DC dividers, containing an adjustable DC voltage source, a calibrated high voltage DC voltage divider, a reference composite DC voltage divider based on resistive elements, containing a high voltage arm, a lockable arm and an output arm, and a double row voltage comparator [2]. At the first stage of measurements, the reference composite DC voltage divider is composed of high-voltage, closable and output arms and measurements are made at a voltage equal to the nominal input voltage of the calibrated DC voltage divider; at the second measurement stage, the reference composite DC voltage divider is made up of high-voltage and output arms and measurements are made at a voltage equal to the nominal input voltage of the calibrated DC voltage divider; at the third measurement stage, the conversion coefficient of the reference composite constant voltage divider, made up of closable and output arms, is determined by an independent verification method.

A disadvantage of the known device (prototype) is the need to carry out the independent verification of the reference composite DC voltage divider, composed of the closable and output arms, at the third stage of measurement. The independent verification method provides high accuracy in measuring the conversion coefficient of the reference composite DC voltage divider, but significantly complicates the calibration process and increases the calibration time of the high voltage DC voltage divider due to the need to additionally perform a certain number of measurements equal to the number of resistive elements making up the closed arm of the reference composite DC voltage divider [2].

The problem to which the invention is directed, is to develop a technical solution that provides a simplification of the calibration process of high voltage DC dividers.

This problem is solved as a result of the fact that in the device for calibrating high-voltage DC dividers containing an adjustable DC voltage source, a calibrated high-voltage DC voltage divider, a reference composite DC voltage divider based on resistive elements, containing a high-voltage arm, a closed arm and an output arm, and two-row voltage comparator, a reference composite DC voltage divider, made in the form of series-connected resistors 's elements comprises a high voltage leg consisting of three or more closable nominally equal resistive elements, and an output port to be alternatively disable the high voltage leg of resistive elements and a reference change ratio conversion of the composite DC voltage divider. The division coefficient of the calibrated high voltage DC voltage divider is determined according to a certain algorithm using a two-row voltage comparator, to the terminals of the first row of which the output arm of the reference composite DC voltage divider is connected, and to the terminals of the second row - the output arm of the calibrated high voltage DC voltage divider.

The simplification of the calibration process of the high voltage DC voltage divider is ensured by the fact that during the operation of the device it is not necessary to independently verify the reference composite DC voltage divider, consisting of a large number of series-connected resistors.

The drawing shows a diagram of a device for calibrating high voltage DC dividers.

A device for calibrating high voltage DC dividers contains an adjustable constant voltage source 1, a reference composite DC voltage divider 2 in the form of series-connected resistive elements, a calibrated high voltage DC voltage divider 3 and a two-row voltage comparator 4.

The composite constant voltage divider 2 contains a high-voltage arm 5 composed of nominally equal resistive elements 6, 7, 8, and an output (low-voltage) arm 9, in parallel with which a trim resistor 10 is connected to balance the measuring circuit. Resistive elements 6, 7, 8 of a high-voltage shoulder 5, which make up the majority of the measuring circuit of a composite reference dc voltage divider 2, each of these elements may consist of a large number of individual resistors. Know the exact values of the resistive elements 6, 7, 8 of the high-voltage arm 5, which make up most of the measuring circuit of the composite reference dc voltage divider 2, as well as the magnitude of their ratio is not required. The calibrated high voltage constant voltage divider 3 contains a high voltage arm 11 and an output (low voltage) arm 12. The output arm 9 of the reference composite constant voltage divider 2 is connected to the terminals 13 of the first row of the two-row voltage comparator 4, and the output arm 12 of the calibrated high voltage constant voltage divider 3 is connected to terminals 14 of the second row of a two-row voltage comparator 4. For switching resistive elements of the reference composite DC voltage divider ereklyuchateli 15, 16, 17 (in the diagram shown in phantom).

The operation of the device for calibrating high voltage DC dividers is as follows.

At the first stage of measurements, a circuit is assembled in accordance with the drawing, with the switches 15, 16, 17 being set to position “2”. A voltage equal to the nominal input voltage of the calibrated high-voltage DC divider 3 is supplied to the circuit from an adjustable DC voltage source 1. The voltage drop across the output arms 9 of the reference composite DC voltage divider 2 and 12 of the calibrated high-voltage DC divider 3 is measured using a two-row voltage comparator 4. The equality is fulfilled:

where R ₆ , R ₇ , R ₈ are the resistances of respectively the resistive elements 6, 7, 8 of the high voltage arm 5 of the reference composite DC voltage divider 2;

R ₉ is the resistance of the output arm 9 of the reference composite constant voltage divider 2;

R ₁₁ , R ₁₂ - resistance, respectively, of high voltage 11 and output 12 arms of a calibrated high voltage DC voltage divider 3;

U ₁₃ , U ₁₄ - readings, respectively, of the first 13 and second 14 rows of a two-row voltage comparator 4.

Equation (1) can be represented as:

where K ₃ is the division coefficient of the calibrated high-voltage DC voltage divider 3;

ρ ₁ = U _13-1 / U _14-1 - the ratio of the readings of the rows of a two-row voltage comparator 9.

At the second measurement stage, the resistive element 6 of the reference composite constant voltage divider 2 is closed (switch 15 is set to position “1”, switches 16, 17 to position “2”). The voltage drop at the output arm 9 of the reference composite constant voltage divider 2 is measured using a two-row voltage comparator 4. A new equality is fulfilled:

Equation (3) can be represented as:

At the third measurement stage, the resistive element 7 of the reference composite constant voltage divider 2 is closed (switch 16 is set to position “1”, switches 15, 17 to position “2”). The voltage drop at the output arm 9 of the reference composite constant voltage divider 2 is measured using a two-row voltage comparator 4. A new equality is fulfilled:

Equation (5) can be represented as:

At the fourth measurement stage, the resistive element 8 of the reference composite constant voltage divider 2 is closed (switch 17 is set to position “1”, switches 15, 16 to position “2”). The voltage drop at the output arm 9 of the reference composite constant voltage divider 2 is measured using a two-row voltage comparator 4. A new equality is fulfilled:

Equation (7) can be represented as:

Solving equations (2), (4), (6), (8) together, we find the conversion coefficient K _{3 of the} calibrated high-voltage DC voltage divider 3 from the obtained values of ρ ₁ , ρ ₂ , ρ ₃ , ρ ₄ :

The conversion coefficient of the reference composite DC voltage divider 2, based on the expressions (1), (9), is equal to:

A feature of the developed device for calibrating high-voltage dc dividers is that during the measurement process, long-term stability of the reference composite dc voltage divider 2 is not required, since the conversion coefficient of the reference composite dc voltage divider is determined directly during the calibration of the high voltage dc voltage divider.

Thus, the proposed technical solution provides a simplification of the calibration process and reduces the calibration time of high voltage DC dividers.

Information sources

1. Zhuravlev E.N. Methods and means of measuring high DC voltages and their metrological support. - M.: Mechanical Engineering, 1982. - S.45-52.

2. Nefediev D.I. Metrological support of high-voltage dividers of constant voltage // Sensors and systems, 2004, No. 1.

Claims (1)

A device for calibrating high-voltage DC voltage dividers, comprising an adjustable DC voltage source, a calibrated high-voltage DC voltage divider, a reference composite DC voltage divider based on resistive elements, containing a high-voltage arm, a lockable arm and an output arm, and a two-row voltage comparator, characterized in that the reference the composite DC voltage divider is made in the form of series-connected resistive elements and contains a high-voltage arm, consisting of three nominally equal closable resistive elements, and an output arm, with the possibility of alternately disconnecting the resistive elements of the high-voltage arm and changing the conversion coefficient of the reference composite constant voltage divider, while the output shoulder of the standard composite constant voltage divider voltages, and the output arm of the calibrated high-voltage DC divider is connected to mam second row of DIP voltage comparator.