RU100284U1 - DEVICE FOR MEASUREMENT AND PROCESSING OF ELECTRIC VALUES IN CHAINS WITH FULL Galvanic isolation - Google Patents

Abstract

 A device for measuring and processing electrical quantities in circuits with full galvanic isolation, containing devices for analog current measurement - current transformer or current shunt and voltage - capacitive voltage divider, analog-digital device and processing device for electrical quantities, characterized in that the current transformer or current a shunt, a capacitive voltage divider and an analog-to-digital device are located on the potential of the circuit with measured values, the device for processing electrical quantities is located It is based on the potential of the measurement circuits, and for galvanic isolation between the analog-to-digital device and the device for processing electrical quantities, an optical data transmission channel is introduced, and a light battery is used to power the analog-to-digital converter, which is constantly illuminated by the light flux from an external light emitter through the air gap or optical fiber.

Description

The utility model relates to digital equipment for measuring and processing instantaneous and effective values of current and voltage in circuits, which must have full galvanic isolation from the measurement circuits.

Digital equipment for measuring and processing instantaneous and current values of current and voltage in circuits, which must have full galvanic isolation from the measurement circuits, are known from the following sources:

1. Current and voltage converters, with current and voltage measurements based on the Faraday and Pockels effects, for example, an NXVCT converter manufactured by NxtPhase T&D Corporation, a description on the Internet: http://pro-ln.ru/en/ production_services / nxvct.html;

2. Current and voltage converters, with current and voltage measurements based on the Hall effect, for example, sensors of types ABS and NCS manufactured by ABB, description on the Internet page: http://fmccgroup.ru/products/protecting_measuring/sensors.

The above sources describe current and voltage converters using digital current and voltage converters, which use as a measuring element:

- The Faraday effect (the effect of rotation of the plane of polarization of linearly polarized light when passing through a substance in a magnetic field);

- The Pockels effect (the effect of the appearance of birefringence in optical media upon application of an electric field);

- The Hall effect (the effect of a change in the voltage on the faces of the material depending on the external magnetic field strength, provided that an electric current flows through the material).

As a galvanic isolation (isolation) of the circuit with measured values from the measurement and processing circuits, air and electrical insulating materials were used.

The closest in technical essence to the patented device for measuring and processing electrical quantities in circuits with full galvanic isolation should be considered the NXVCT converter manufactured by NxtPhase T&D Corporation (NxtPhase) described in the first source.

This converter contains:

- Insulation column;

- A current head, which is a few turns of a measuring optical fiber around a current conductor;

- Three electro-optical crystals (Pockels cells);

- Cable path, including cable box, feeder and trunk cables;

- Modular electronics kit.

A modular set of electronics emits a light wave with a certain polarization into a measuring optical fiber and into electro-optical crystals (Pockels cells).

When a current flows in a current head around a current conductor, a magnetic field arises that affects the angle of rotation of the polarization of the light passing through the measuring optical fiber.

When voltage is applied, an electric field appears, which begins to act on electro-optical crystals (Pockels cells), and the polarization of light begins to change in them.

The modular set of electronics, having received the signal back from the measuring optical fiber and electro-optical crystals (Pockels cells), light, measures its polarization, and calculates the value of current and voltage, and performs further digital processing of the measured electrical quantities.

A disadvantage of the known device for measuring and processing electrical quantities in circuits with complete galvanic isolation is the complexity and high cost of the device, due to the availability of expensive and complex optical equipment - a laser with a strictly defined wavelength, a planar and circular polarizer, a measuring optical fiber, electro-optical crystals, an optical receiver radiation.

A useful model solves the problem of creating a device for measuring and processing electrical quantities in circuits with complete galvanic isolation using simple optical components in its design.

The technical result that is achieved by the utility model is to simplify the design and reduce the cost.

This is achieved by the fact that in the device for measuring and processing electrical quantities in circuits with full galvanic isolation, devices for analog current measurement - an electromagnetic current transformer or current shunt, and voltage measurements - a capacitive voltage divider are introduced into a circuit with measured electrical quantities. An analog-to-digital device is placed on the potential of the circuit with measured electrical quantities, which allows converting instantaneous values of current and voltage taken from the measuring devices into a digital code, which can be further processed digitally without further conversion. An analog-to-digital device emits a luminous flux of a correspondingly converted code using a light emitter, which is sent through the air gap or through an optical fiber to a digital device for processing electrical quantities, where it is processed digitally without additional conversion. The analog-digital device is powered by a light battery, which is constantly illuminated by the light flux from an external light emitter through an air gap or optical fiber.

The introduction of simple devices for measuring current (electromagnetic current transformer or current shunt) and voltage (capacitive voltage divider) in conjunction with an analog-to-digital converter on the side of the circuit with measurable electrical quantities, with the transmission of a digital code for processing through the optical communication channel, which is galvanic by decoupling, it will allow to abandon complex and expensive optical devices for measuring the strength of magnetic and electric fields.

The utility model is illustrated by the drawing, where figure 1 shows a sketch of a patented device for measuring and processing electrical quantities in circuits with full galvanic isolation.

A device for measuring and processing electrical quantities in circuits with full galvanic isolation contains a part of circuit 1, in which the measurement of electrical quantities is carried out. In circuit 1, a device for measuring current is included - an electromagnetic current transformer 2 or current shunt 3. The upper plate 4 is connected to circuit 1, which together with the middle plate 5 and the lower plate 6 forms a capacitive voltage divider. An analog-to-digital device 7 with a light battery 8 and a light emitter 9 is placed on the potential of circuit 1. Parts located on the potential of the circuit with measured electrical quantities are located on the insulating column 10. At the potential for processing electrical quantities is a device for processing electrical quantities 11 and a light emitter 12.

A device for measuring and processing electrical quantities in circuits with full galvanic isolation is as follows. When the measured current flows through circuit 1, and accordingly through an electromagnetic current transformer 2 or current shunt 3, a value proportional to the measured current in circuit 1 will appear on the terminals of these devices, due to the insulation between circuit 1 and electromagnetic current transformer 2 or current shunt 3 requires a minimum, these devices will have high conversion accuracy. When voltage is applied in circuit 1 relative to another potential (on which the device for processing electrical quantities 11 is located), an electric field is formed between the upper plate 4 and the lower plate 6. Between the upper plate 4 and the middle plate 5, respectively, a voltage appears that will be proportional to the voltage between the plates 4 and 6, that is, the measured voltage. Due to the fact that the cover 5 is close enough to the cover 4 (i.e., to the cover with the potential of the circuit with measurable electrical quantities), a change in the external background of the electric field due to a change in the position of any external objects will give a very slight change in potential on the cover 5, then there is a voltage measurement will be made with high accuracy, despite the introduced distortions in the electric field from external objects. The analog-to-digital device 7 receives signals from a current transformer 2 or current shunt 3 and the voltage from the plates 4 and 5. These signals in the analog-to-digital device 7 are converted into a digital code. The luminous flux modulated by the code from the light emitter 9 is sent to an electric quantity processing device 11, where it is converted back to a digital code, where it is processed digitally without additional conversion. The light emitter 12 generates a light flux to the light battery 8, which converts this light flux into electrical energy, due to which the analog-to-digital device 7 is powered.

Thus, a device for measuring and processing electrical quantities in circuits with complete galvanic isolation without the use of expensive and complex optical equipment — an emitting laser with a strictly defined wavelength, a planar and circular polarizer, a measuring optical fiber, electro-optical crystals, and an optical radiation receiver with preserving the full galvanic isolation.

Claims (1)

A device for measuring and processing electrical quantities in circuits with full galvanic isolation, containing devices for analog current measurement - current transformer or current shunt and voltage - capacitive voltage divider, analog-digital device and processing device for electrical quantities, characterized in that the current transformer or current a shunt, a capacitive voltage divider and an analog-to-digital device are located on the potential of the circuit with measured values, the device for processing electrical quantities is located It is based on the potential of the measurement circuits, and for galvanic isolation between the analog-to-digital device and the device for processing electrical quantities, an optical data transmission channel is introduced, and a light battery is used to power the analog-to-digital converter, which is constantly illuminated by the light flux from an external light emitter through the air gap or optical fiber.