RU166063U1 - DEVICE FOR CURRENT AND VOLTAGE MEASUREMENTS IN A HIGH VOLTAGE NETWORK - Google Patents

Abstract

A device for measuring current and voltage in a high-voltage network, containing primary scale converters of current and voltage, analog-to-digital converters with an optical output for signals of the measured current and voltage, optical fibers for transmitting a signal of the measured current and voltage, a receiving device, characterized in that a digital converter with an optical output for the current signal is on the high potential side and is powered by a fast saturating current transformer, and an analog-to-digital converter with an optical output for the voltage signal is on the low potential side, and is powered by an external power source.

Description

The utility model relates to electrical high-voltage equipment for large-scale conversion of current and voltage to values suitable for measurement with standard electrical measuring instruments.

High-voltage electrical equipment for large-scale conversion of current and voltage, currently known are the classic electromagnetic current and voltage transformers, as well as voltage dividers, a description of which can be found, for example, in the following sources:

1. Barzilovich V.M. High voltage current transformers. L .: Gosenergoizdat, 1962

2. Bachurin N.I. Current transformers. L .: "Energy", 1964

3. Vavin V.N. Current transformers. M .: "Energy", 1966

4. Vavin V.N. Voltage transformers and their secondary circuits. 2nd ed. -M .: "Energy", 1977

5. Current transformers / V.V. Afanasyev, N.M. Adonyev, V.M. Kibel et al. - 2nd ed., - L .: Energoatomizdat. Leningra. Sep., 1989

To more modern developments of electric high-voltage equipment for large-scale conversion of current and. voltages include converters with current and voltage measurements based on the Faraday and Pockels effects, for example, an NXVCT converter manufactured by NxtPhase T&D Corporation, which is described in the following source:

6. Internet link:

http://pro-ln.ru/ru/production_services/nxvct.html.

Also, more modern equipment includes transducers with current and voltage measurements based on the Hall effect, for example, ABS type sensors NCS or ES, which are described in the following source:

7. Internet link:

http://fmccgroup.ru/products/protecting_measuring/sensors.

Current and voltage converters are also well known, including classical current transformers and voltage dividers, with further transmission and conversion of information about the measured current and voltage via optical communication channels, while the optical channel simultaneously serves as isolation from high voltage and galvanic isolation. Such converters are known from the following sources:

8. RF patent for utility model No. 100284 “Device for measuring and processing electrical quantities in circuits with full galvanic isolation”;

9. RF patent for the invention No. 2365922 "Optoelectronic current sensor";

10. RF patent for the invention No. 2516034 "Device for measuring current and voltage in a high-voltage network."

The closest in technical essence to the patented device should be considered the converter described in the last source.

The described device contains:

- Primary scale current transducer (electromagnetic current transducer or current shunt);

- Primary scale voltage converter (high-resistance voltage divider) with leads to the high potential side;

- An analog-to-digital converter with an optical output of the converted signal;

- Power Supply;

- Fast saturating current transformer;

- An additional winding of a rapidly saturable current transformer;

- Trigger device with an electromechanical or electronic key;

- Insulation design (insulator);

- Optical fiber (optical glass fiber);

- The receiving device.

When a high voltage current flows, current is measured using a primary scaled current converter, and voltage is measured using a high-resistance voltage divider. The measured values are transmitted to an analog-to-digital converter with an optical output, where the signal is encoded and transmitted through the fiber to the low potential side, followed by decryption in the receiving device.

The power supply receives energy from the high-voltage network through a fast-saturable transformer. In the event of a loss of current in the high-voltage network, and the presence of a high voltage, the trigger device connects an additional winding in a rapidly saturable current transformer, and current flows from the high-voltage network to the primary large-scale voltage converter through it. At the same time, the power of the analog-to-digital converter does not stop, since current flows through the rapidly saturating current transformer, providing electrical power. When current appears in the high-voltage network, the trigger device turns off the additional winding, and the rapidly saturable current transformer starts to work as usual.

A disadvantage of the known device for measuring current and voltage in a high voltage network is the low measurement accuracy at low currents. When current flows in the network, the value of which lies in the response area of the trigger device, the power of the analog-to-digital converter will constantly switch from power from the flowing current to power from the additional winding, introducing various transient values into the measurements. The additional winding, in addition, will introduce an error into the voltage measurement, since it additionally loads the primary scale voltage converter with parasitic current.

In addition, the placement of a large number of electronic units (two converters, a power supply side, a trigger device), even in a shielded case on the high potential side, makes the device unreliable.

A useful model solves the problem of increasing the conversion accuracy, simplifying the device as a whole, transferring part of the electronic components to the low potential side, which ultimately increases the reliability of the device as a whole.

A useful model solves the problem of creating a device for measuring current and voltage with high accuracy and high reliability.

This is achieved by the fact that the measurement of high voltage will be performed by the same primary large-scale voltage converter (high-resistance voltage divider), but with leads to the low potential side. At the same time, the trigger device, the additional winding in the rapidly saturable current transformer will be excluded from the design, and the energy consumption of the analog-to-digital converter will be reduced by half - now only one signal of the measured current is subject to encoding. On the low potential side, to increase the measurement accuracy, an analog-to-digital converter is installed, the power of which is carried out using an external power supply. Next, the optical signals from both digital-to-analog converters are fed to the receiving device, where further processing and generation of current and voltage signals in analog form takes place.

The transfer of voltage measurement and an analog-to-digital converter for measuring voltage to the low voltage side will allow you to abandon the trigger device and additional winding in a fast-saturable transformer, increase the measurement accuracy regardless of the flowing current, and increase the reliability of the whole device.

The utility model is illustrated by the drawing, where figure 1 shows a sketch of a patented device for measuring current and voltage in a high voltage network.

A patented device for measuring current and voltage in a high-voltage network contains:

1 - main insulation (for example, a high voltage insulator);

2 - Fast saturating current transformer;

3 - Primary scale voltage converter (high-resistance voltage divider);

4 - An analog-to-digital converter with an optical output of a current signal;

5 - Primary scaled current transducer (for example, electromagnetic current transducer or current shunt);

6 - power supply;

7 - Line voltage;

8 - An analog-to-digital converter with an optical output of a voltage signal;

9 - Optical fiber (optical glass fiber) for transmitting a current signal;

10 - Optical fiber (optical glass fiber) for transmitting a voltage signal;

11 - receiving device;

12 - External power supply.

Patented device for measuring current and voltage in a high voltage network operates as follows. When the measured current flows through a large-scale current transducer 5, a large-scale current conversion occurs. It is impossible to transmit the received signal directly, since these elements are on the high voltage side. The measured signal is transmitted to an analog-to-digital current converter with optical output 4, and is transmitted directly to the receiving device 11 through a fiber for transmitting the current signal 9, where it is decoded and issued in a large-scale analog form for measurement by standard electrical measuring devices. The analog-to-digital converter with an optical current output 4 is powered from a power supply 6, which in turn receives power from a rapidly saturable current transformer 2. Voltage is measured by a primary large-scale voltage converter 3 with leads to the low potential side. The signal of the measured voltage is fed to an analog-to-digital voltage converter 8 mounted on the low potential side. The signal is converted into optical form, and through a fiber for transmitting the voltage signal 10 is transmitted to the receiving device 11, where it is decoded and issued in large-scale analog form for measurement by standard electrical measuring devices. The power of the analog-to-digital voltage converter 8 is provided from an external power supply unit 12 via a voltage supply line 7.

Thus, a device for measuring current and voltage with greater measurement accuracy and with greater reliability.

Claims (1)

A device for measuring current and voltage in a high-voltage network, containing primary scale converters of current and voltage, analog-to-digital converters with an optical output for signals of the measured current and voltage, optical fibers for transmitting a signal of the measured current and voltage, a receiving device, characterized in that the analog a digital converter with an optical output for the current signal is on the high potential side and is powered by a fast saturating current transformer, and an analog-to-digital converter with an optical output for the voltage signal is on the low potential side, and is powered by an external power source.

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