RU162879U1 - AC METER - Google Patents

Abstract

1. An alternating current meter comprising a conductive bus onto which a supply current transformer and a Rogowski coil are mounted, a temperature sensor, an analog-to-digital converter, a signal processing unit connected to an optical transceiver, and a power supply unit, characterized in that it further comprises an electromagnetic screen, protecting supply current transformer and Rogowski coil, electrostatic screen, protecting electro-optical unit for measuring AC current, electro-static processing unit information connected by a fiber optic cable providing backup power, as well as a data flow controller and a wireless interface module. 2. An alternating current meter according to claim 1, characterized in that the electromagnetic shield protecting the supply current transformer and the Rogowski coil is made in the form of a pipe segment of a ferromagnetic material with a magnetic permeability greater than 1.3. An alternating current meter according to claim 1, characterized in that the data flow controller provides support for the industry standard IEC 61850-9-2.4. An alternating current meter according to Claim 1, characterized in that a laser with an optical power of at least 300 mW is used for backup power via a fiber optic cable. An alternating current meter according to claim 1, characterized in that galvanic isolation is ensured between the electron-optical unit for measuring alternating current and the electron-optical unit for processing information through the use of a fiber optic cable.

Description

Technical field

This utility model relates to measurement technique, namely to devices that allow measuring alternating current in high voltage power lines.

State of the art

From the existing level of technology, the utility model “A device for detecting current pulses during lightning surges in power lines” is known [Pat. RF No. 119122 z. 04/11/2012, publ. 08/10/2012], containing a controller, a supply winding and a voltage converter connected in series, the output of which is connected to the controller’s power input, an ionistor connected to the controller’s power input, a current transformer and a three-channel ADC, the output of which is connected to the controller, a temperature sensor, an output which is connected to the second input of the ADC, a voltage sensor, the output of which is connected to the controller, a storage device and a radio frequency transceiver connected to the controller, characterized in that a comparator and a peak detector are additionally introduced, inputs connected to a current transformer, a timer, a start input connected to the output of the comparator, and an output to a controller, while the control input of the peak detector is connected to the output of the comparator, and the output to the third input of the ADC.

Closest to the claimed technical solution is "High-voltage digital device for measuring current" [Pat. RF №152974 s. 09/15/2014, publ. 06/27/2015], containing a powering electromagnetic transformer and a Rogowski belt, covering a current-carrying conductor with a measured current; a cylindrical shunt with an internal cavity included in the dissection of the current lead; a current-voltage converter, a voltage stabilizer, a signal processing unit with an analog-to-digital converter, and a first optical transceiver placed inside the shunt; optical channel; a second optical transceiver, router, and power supply located on the low voltage side; wherein the supply electromagnetic transformer is connected to a current-voltage converter, which is connected to a voltage stabilizer connected to the signal processing unit and to the first optical transceiver, potential shunt electrodes and Rogowski belt are connected to the signal processing unit, which is connected to the first optical transceiver, through the optical a channel connected to a second optical transceiver connected to a router, a power supply connected to a second optical transceiver sensor and router, characterized in that it further comprises a magnetotransistor transducer and a measuring electromagnetic current transformer, covering the conductor with the measured current, and a synchronization unit with an accurate time system, a battery and a light-to-electric converter of electric energy, placed inside the shunt, an optical radiation generator located on the low-voltage side, the second optical channel, while the magnetotransistor converter, measuring electromagnetic tr The current converter and the output of the synchronization unit with the exact time system are connected to the signal processing unit, the input of the synchronization unit with the exact time system, the battery and the light-to-electric converter are connected to the voltage regulator, the second output of the power supply is connected to the optical radiation generator, through the second optical a channel connected to a light energy to electric converter.

The disadvantages of this technical solution are as follows. Firstly, the presence of 2 measuring transformers, which complicates the signal processing system. Secondly, the presence of a separate time synchronization system, which should be on the low-voltage side. Thirdly, there is no support for the industry standard for information transfer IEC 61850-9-2, which simplifies the integration of the system into industrial digital networks SMART GRID. Fourth, the absence of electrostatic and magnetic shielding of the Rogowski coil, which significantly increases the risk of the influence of external factors on the measurements. Fifth, the presence of batteries in the field circuit necessitates periodic maintenance of the power circuit or the replacement of its elements. Also, due to the fact that the sensor is in external conditions with possible seasonal temperature differences from -60C to + 60C, the resource of such batteries is very limited.

SUMMARY OF THE INVENTION

The task to which the claimed utility model is directed is to increase the efficiency of using an alternating current meter by reducing its overall dimensions (weight and volume), increasing safety and reliability, and also by ensuring that it supports the industrial standard IEC 61850-9-2 .

1. This problem is solved due to the fact that the alternating current meter declared as a utility model contains a conductive bus on which a supply current transformer and a Rogowski coil are installed. It also contains a temperature sensor, an analog-to-digital converter, a signal processing unit connected to an optical transceiver, and a power supply. The meter further comprises an electromagnetic screen protecting the supply current transformer and Rogowski coil and an electrostatic screen protecting the electron-optical unit for measuring AC current. The utility model includes an electron-optical information processing unit connected by a fiber optic cable to a backup power source, as well as a data flow controller and a wireless interface module.

In this case, the electromagnetic shield protecting the supply current transformer and Rogowski coil is made in the form of a pipe segment made of ferromagnetic material with magnetic permeability greater than 1.

The data flow controller provides support for the industry standard IEC 61850-9-2.

For backup power via fiber optic cable, a laser with an optical power of at least 300 mW was used.

And between the electron-optical unit for measuring AC current and the electron-optical unit for processing information, galvanic isolation is ensured through the use of a fiber optic cable, which increases the reliability and safety of the AC meter.

Brief Description of the Drawings

The essence of the utility model is illustrated by drawings.

In FIG. 1 circuit meter AC

Conductive bus 1, supply current transformer 2, Rogowski coil 3, temperature sensor 4, input analog part 5, analog-to-digital converter 6, signal processing unit 7, electron-optical converter 8, power supply 9, electromagnetic screen 10, electron-optical AC measuring unit (high voltage part) 11, electrostatic screen 12, electronic-static information processing unit 13, wireless interface module 14, data flow controller 15, fiber optic cable 16, process bus (IEC 61850-9-2) 17, neither high voltage part 18.

DETAILED DESCRIPTION OF THE INVENTION

The device operates as follows.

The AC meter is divided into two parts: a high-voltage part (an electro-optical unit for measuring alternating current) 11 and a low-voltage part 18 to obtain information about the measured values of current, temperature, their mathematical processing and data output to the industrial network. When electric alternating current flows through the current-carrying bus 1, the current passes through the supply current transformer 2 and Rogowski coil 3, in which the emf is induced.

EMF induced in the Rogowski coil is equal to the rate of change of flux linkage:

where: e is the instantaneous value of the EMF induced in the winding of the Rogowski coil, B;

M = µ ₀ · S · n / l - mutual inductance between the coil of the Rogowski coil and the conductor with the measured current, GN.

The ratio (1) in the operator form:

where: p is the Laplace differential operator.

Since the EMF is proportional to the rate of change of current, the task of measuring current requires the integration of the output signal of the Rogowski coil. In the input analog part 5, active integration is implemented in the input amplifier-integrator.

Further, from the input analog part, the analog information about the current strength is supplied to the analog-to-digital converter 6, where the information (signal) from the analog format is converted to digital format. Then the signal (information) enters the electron-optical converter 8, which generates digital data packets for transmission via fiber-optic cable 16 to the low-voltage part 18, after which it enters the electron-static information processing unit 13, where additional mathematical processing and transmission of digital data packets to the data stream controller 15 and the wireless interface module 14. In the data stream controller 15, the digital data array is formatted and transferred to the process bus (IEC 61850- 9-2LE) 17,

The temperature sensor 4 mounted on the Rogowski coil is connected to the processing unit 7, which reads a signal about the temperature value.

The electron-optical unit for measuring alternating current (high-voltage part) 11 is powered by a power supply 9, in which the main power source is a supply current transformer 2, and the backup one is powered by a fiber optic cable 16 by converting radiation energy into electrical energy.

As a result of using a backup power source via fiber-optic cable, it became possible not to use batteries as a backup power source, and there was no longer a need for a charging system for these batteries, which simplified the design and reduced dimensions (approximately by 20%)

In view of the use of a fiber optic cable as a transmission of information and energy from the low-voltage part 18 to the high-voltage 11, the condition for the complete galvanic isolation of these parts from each other is fulfilled, which increases the safety and reliability of the system, namely, the low-voltage part 18 cannot be affected by high-voltage pulses (for example , thunderstorms) from the high-voltage part 11, which can disable equipment located in close proximity to the low-voltage part 18.

The technical result provided by the given set of features is an alternating current meter, which, in comparison with analogs, can be used more efficiently by reducing its overall performance, increasing safety and reliability (through shielding and galvanic isolation), and also by providing them with industrial support standard IEC 61850-9-2.

Claims (5)

1. An alternating current meter comprising a conductive bus onto which a supply current transformer and a Rogowski coil are mounted, a temperature sensor, an analog-to-digital converter, a signal processing unit connected to an optical transceiver, and a power supply unit, characterized in that it further comprises an electromagnetic screen, protecting supply current transformer and Rogowski coil, electrostatic screen, protecting electro-optical unit for measuring AC current, electro-static processing unit information connected by a fiber optic cable providing backup power, as well as a data flow controller and a wireless interface module. 2. The AC meter according to claim 1, characterized in that the electromagnetic shield protecting the supply current transformer and the Rogowski coil is made in the form of a pipe segment of a ferromagnetic material with a magnetic permeability greater than 1. 3. The AC meter according to claim 1, characterized in that the data flow controller provides support for the industry standard IEC 61850-9-2. 4. The AC meter according to claim 1, characterized in that a laser with an optical power of at least 300 mW was used for backup power via fiber optic cable. 5. AC meter according to claim 1, characterized in that between the electronic-optical unit for measuring alternating current and the electronic-optical unit for processing information, galvanic isolation is achieved through the use of fiber optic cable.

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