RU86318U1 - DEVICE FOR TESTING ELECTRIC METERS - Google Patents

Abstract

A device for checking electrical measuring devices, comprising a transformer that performs the function of both step-up and step-down transformers, characterized in that a control device connected to the front panel, the processor, the common channel connector, the alternating voltage driver is inserted into it; a meter, an output amplifier, the input of the transformer connected to the output of the output amplifier, the input of which is connected to an AC voltage generator, whose bi-directional input-output is connected to the output of the control device, whose bi-directional input-output is connected to the output of the meter, the input of which is connected to the transformer lowering , is the control object in the circuit of automatic voltage regulation on the boost winding.

Description

The utility model relates to devices of electrical measuring equipment and can be used to verify kilovoltmeters, as well as a calibrated high voltage source for laboratory research.

Currently, verification of electrical measuring instruments (EIT) is carried out in accordance with instruction 184-62, which regulates the means and methods of verification [1], as well as GOST 8.497-83 [2].

The most widely used such means of verification:

- Voltage transformer I-510 up to 15 kV [3].

- Voltage transformer NLL-15 up to 15 kV [4].

- Voltage transformer NLL-30 up to 30 kV [4].

These means of verification have a number of significant drawbacks, namely:

- are oil-filled, requiring regular maintenance (measuring transformer I-510);

- have large dimensions and weight (measuring transformers NLL-15, NLL-30);

- for checking kilovoltmeters with measurement limits of 1-30 kV, a set of two transformers is required;

- there is no automation of the measurement process and remote control of the device, which does not exclude the factor of subjective assessment of the verification object.

In addition, the step-up transformer (first) is connected to an industrial AC network, the quality of which does not always correspond to the verification conditions.

As a prototype, a kilovoltmeter calibration device was selected, containing two high-voltage measuring transformers [1].

In this device, the first transformer is step-up, to the high-voltage winding of which a calibrated kilovoltmeter and the high-voltage winding of the second transformer, which is step-down, are connected. Measuring the voltage on the step-down winding of the second transformer, taking into account its transformation coefficient, judge the magnitude of the high voltage.

Since the prototype uses verification tools [3], [4], it has the disadvantages indicated above.

The task that the proposed utility model solves is to increase autonomy, automate the measurement process, reduce the size and weight, allow remote control of the output voltage and frequency, reduce deviations to the minimum output parameters from the nominal when exposed to external factors (time, quality of electricity in the place of verification, temperature).

This is achieved by the fact that a control device connected to the front panel, processor, common channel connector, alternating voltage generator is introduced into the calibration device for electrical measuring instruments, containing a transformer that performs the functions of both step-up and step-down transformers; a meter, an output amplifier, the input of the transformer connected to the output of the output amplifier, the input of which is connected to an AC voltage driver, whose bi-directional input-output is connected to the output of the control device, whose bi-directional input-output is connected to the output of the meter, the input of which is connected to the transformer lowering winding , is the control object in the circuit of automatic voltage regulation on the boost winding.

The figure shows a structural electrical diagram of the device, where indicated:

1 - front panel;

2 - bidirectional data bus;

3 - control device;

4, 5 - bidirectional data buses;

6 - processor;

7, 8 - bidirectional data buses;

9 - shaper alternating voltage;

10 - meter;

11 - lowering feedback winding of the transformer 12;

12 - transformer;

13 - output amplifier;

14 - field winding of the transformer 12;

15 - boost winding of the transformer 12.

The calibration device for electrical measuring devices contains a control device 3, connected via the bus 7 to the input of the alternating voltage driver 9, the output of which is connected to the input of the output amplifier 13, the output of which is connected to the excitation winding 14 of the transformer 12, the lowering winding 11 of which is connected to the input of the meter 10, the output the meter 10 on the bus 8 is connected to the control device 3; bus 2 connects the control device 3 to the front panel 1, bus 4 connects the control device 3 to the connector of the public channel (CPC), bus 5 connects the control device 3 to the processor 6.

The operation of the device is as follows. In the control device 3 under the control of the processor 6, according to the program available in it, the control signals are analyzed from the front panel 1 or from the CPC bus 4. As a result, the device operation mode is selected:

- manual using the keyboard of the front panel 1;

- remote from the external computer via the bus 4 CPC.

In all cases, on the control panel 1, which includes the manual controls of the device, a five-digit digital indicator, single indicators, the status, operation mode of the device and the voltage value that should be on the boost winding 15 of transformer 12 are displayed. Via bus 7 from control device 3 the digital voltage generator 9 receives a digital code corresponding to the set voltage. The AC voltage generator 9 generates a sinusoidal voltage from 0 to 4.2 V with a frequency of 45 to 55 Hz supplied to the output amplifier 13 having a gain of 50 at a load current of up to 2 A. The amplifier 13 is loaded on the excitation winding 14 of the transformer 12. Number ratio turns of winding 15 to the number of turns of winding 14 of transformer 12 is 1000, so if, for example, voltage on winding 15 is 30,000 V, then on winding 14 of transformer 12 it will be 30 V. The sinusoidal voltage from winding 11 of transformer 12 having an output for counter For external measuring instruments, it enters a meter 10 that performs analog-to-digital conversion, the output of which is connected via a bus 8 to a control device 3, where the data is compared on a “more or less” basis with data received from the control panel 1 or from bus 4 CPC. If the data differs, then depending on the comparison result along the circuit “control device 3 — AC driver 9 — output amplifier 13 on winding 14, such voltage is set in inverse proportion so that the data from meter 10 does not differ from the data set on front panel 1 . Thus, the automatic regulation of the output voltage occurs. The resolution of the output voltage setting at the limit of 10 kV is 0.1 V, and in the range from 10001 to 30000 V - 1 V. The error in setting the high voltage on the transformer 12 is 0.2%. Harmonic coefficient does not exceed 0.15%.

The claimed device, as well as the program and methodology for checking electrical meters using the claimed device, were developed by FSUE NNIPI “Quartz” and will be used in metrological units of the Russian army.

Bibliographic data

1. Instruction 184-62 on the verification of ammeters, voltmeters, wattmeters and varmeters.

2. GOST 8.497-83.

3. K.K. Ilyunin, D. I. Leontiev and others. A reference to electrical measuring instruments. "Energy" 1973.

4. Measuring transformers NLL-15, NLL-30. Technical description and instruction manual.

Claims (1)

A calibration device for electrical measuring instruments, comprising a transformer that performs the function of both step-up and step-down transformers, characterized in that a control device connected to the front panel, the processor, the public channel connector, the alternating voltage driver is inserted into it; a meter, an output amplifier, the input of the transformer connected to the output of the output amplifier, the input of which is connected to an AC voltage generator, whose bi-directional input-output is connected to the output of the control device, whose bi-directional input-output is connected to the output of the meter, the input of which is connected to the transformer lowering winding , is the control object in the circuit of automatic voltage regulation on the boost winding.