KR101326730B1 - Calibration device for transformer monitoring module - Google Patents

Abstract

A compensator for a transformer monitoring module is disclosed. The compensator for a transformer monitoring module is a device which is installed on a data concentrator for an advanced metering infrastructure (AMI) and which compensates for a probe and a transformer monitoring module with a transformer load monitoring function. The probe and the transformer monitoring module are installed on the compensator for a transformer monitoring module. The probe comprises a voltage conversion unit receiving a voltage from a voltage source, converting the voltage into a predetermined voltage, and outputting the voltage and a current conversion unit receiving a current from a current source and outputting the current proportional to the number of coils. The transformer monitoring module detects an output voltage of a voltage applying unit and the output current of the current conversion unit and compensates for errors by using compensation values including error information of the probe. [Reference numerals] (11) R phase probe;(12) S phase probe;(13) T phase probe;(20) Interface unit;(30) Surge/noise protection circuit;(40) Transformer monitoring module

Description

Transformer monitoring module compensator {CALIBRATION DEVICE FOR TRANSFORMER MONITORING MODULE}

To the present invention is to ensure the measurement accuracy of that, more specifically, the transformer load monitoring module according to the calibration apparatus of the transformer load monitoring module included in the data concentrator (DCU, Data Concentration Unit) for AMI (Advacned Metering Infrastructure) error It relates to a transformer monitoring module compensation device for correcting the.

Voltage and current, which are continuous signals, are detected by the voltage and current sensors and converted into discrete signal strings. At this time, measurement errors such as signal distortion due to characteristics of the device occur. Current detection uses shunt resistors, current transformers (CTs) or hall sensors, and many current transformers with excellent insulation properties are used in industry.

Among the current transformers, the winding ratio of the coil is used to insulate the first and second circuits, but a phase error occurs. In addition, the current transformer has a disadvantage that the hysteresis occurs when the current exceeds the allowable input current saturation state. Therefore, when using a current transformer, it is inevitable that the phase of the primary input current and the detected secondary output signal are slightly distorted by the coil component or the like. This causes non-linear measurement error, so it cannot be solved simply by adjusting the gain, and high-precision performance can be obtained by proper phase correction.

The transformer load monitoring function included in the data concentrator performs the role of a real-time transformer monitoring diagnosis system by measuring information such as current, voltage, active power, reactive power, power factor, etc. for each phase and transmitting it to the upper server system. To this end, the accuracy of the load monitoring information measured by the data intensive system must be guaranteed. As an example, referring to the data concentrator specification (GS-5895-0026), the measurement range is 85 [V] to 260 [V] in voltage (rms), and the measurement accuracy is maintained at 0.5% or less and measured in current (rms). It is designed to maintain the range 0 [A] ~ 760 [A], measuring accuracy less than 1% or 1A, and the effective power and reactive power are standardized to ensure the accuracy equivalent to or higher than that of CT (Current Transformer) low voltage electronic meter. have.

In order to ensure the accuracy of the load monitoring information of such a data intensive device, a calibration process as in a general electricity meter is required. To this end, an AC electrostatic source (constant current, constant voltage, constant frequency) generator that satisfies all of the voltage, current measurement range, and measurement accuracy described in the above specification is required, but it does not exist at home or abroad.

Therefore, as an alternative to the current, the current measurement range is divided by the probe CT ratio of the data concentrator, and then the current is applied to the CT secondary side, and the voltage corresponding to the voltage measurement range is set to be applied directly. I am correcting

However, since this method does not consider the error of the probe itself at all, there is a big problem that precision error cannot be satisfied. In addition, since the current and voltage are directly connected to the data intensive device each time, the method of correcting the current intensive voltage is very troublesome in mass production of the data intensive device, and thus the productivity is very low.

The technical problem to be achieved by the present invention is to provide a transformer monitoring module correction apparatus capable of performing a correction in consideration of the probe error in order to ensure the accuracy of the transformer load monitoring information obtained from the data intensive device.

In addition, to provide a transformer monitoring module correction device that can improve the mass productivity of the data intensive device by correcting the errors of the plurality of transformer monitoring module by one error correction.

According to an aspect of the present invention, a transformer monitoring module correction apparatus for calibrating a probe and a transformer monitoring module mounted on an AMI (Advanced Metering Infrastructure) data performing a transformer load monitoring function, the probe and transformer monitoring module Is mounted, the probe includes a voltage conversion unit for receiving a voltage from a voltage source and converting to a predetermined voltage and outputting a current and a current conversion unit for receiving a current from a current source and outputting a current proportional to the number of turns, the transformer monitoring module Provides a transformer monitoring module correction apparatus for detecting an output voltage of the voltage applying unit and an output current of the current converter and performing error correction using a correction value including error information of the probe.

The current converter is a current transformer (CT), the primary side may receive a current from the current source, the secondary side may output the current to the transformer monitoring module.

The number of turns of the current converter may have a value of 4 to 7.

The transformer monitoring module calculates transformer load monitoring information including current (rms), voltage (rms), and power factor by using the output voltage and output current output from the probe, and generates a pulse output proportional to an effective or reactive power amount. A meter engine unit to generate; And a metering unit controlling the meter engine unit and integrating the amount of power.

The meter engine unit includes an analog front end (AFE) circuit for converting the output voltage and the output current into a digital value and the output voltage and output current from the output voltage and the output current converted into the digital value. It may be composed of a CE (Compute Engine) for calculating the amount of reactive power and generates a pulse output proportional to the amount of reactive power and delivers it to the meter.

The metering unit stores the current, voltage, and power factor calculated by the CE, integrates the effective and reactive power amounts using the pulse output value, and performs error correction using a correction value including error information of the probe. It may include a micro-controller unit (MCU), the memory and a real time clock (RTC).

An interface unit may be further included to fix the probe and allow the current source to be wound on a primary side of the current converter.

It may further include a surge / noise protection circuit connected to the input terminal of the transformer monitoring module to prevent a sudden change in the output voltage and output current, and to block the noise flowing from the outside.

The transformer monitoring module and the probe may be removable.

The inventors of the transformer monitoring module correction apparatus of the present invention can perform the correction considering the probe error in order to ensure the accuracy of the transformer load monitoring measurement information presented in the data concentrator standard.

In addition, the mass productivity of the data intensive device can be improved by correcting the errors of the plurality of electronic wattmeter correction devices with one error correction.

1 is a block diagram of a transformer monitoring module correction device according to an embodiment of the present invention,
2 is a circuit diagram of a current converter according to an embodiment of the present invention;
3 is a configuration diagram of a transformer monitoring module according to an embodiment of the present invention;
Figure 4 is a connection diagram of the transformer monitoring module correction device and the error test bench according to an embodiment of the present invention, and
5 is a connection diagram of a transformer monitoring module correcting apparatus and an error test bench according to another exemplary embodiment of the present invention.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated and described in the drawings. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms including ordinal, such as second, first, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the second component may be referred to as a first component, and similarly, the first component may also be referred to as a second component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant description thereof will be omitted.

1 is a block diagram of a transformer monitoring module correction device 100 according to an embodiment of the present invention. Transformer monitoring module correction device 100 according to an embodiment of the present invention receives a voltage from a voltage source and converts it into a predetermined voltage and outputs a current proportional to the number of windings received a current from a current source and a voltage converter The probe 10 includes a current converter, a transformer monitoring module 40 for detecting an output voltage of the voltage applying unit and an output current of the current converter and performing error correction with a correction command of the correction terminal device 300.

3 is a block diagram of a transformer monitoring module 40 according to an embodiment of the present invention. Transformer monitoring module 40 according to an embodiment of the present invention is the AFE circuit 42 (Analog Front End) for converting the output voltage and output current to a digital value and the current from the output voltage and output current converted into a digital value, It calculates the voltage, power factor, effective and reactive power and generates a pulse output proportional to it, and transmits the result to the metering unit 45 using CE (Compute Engine), which is effective by using a pulse output value. The MCU 46 (Micro Control Unit), the memory 47, and the RTC 48 (Real Time Clock) for integrating the amount of reactive power and performing error correction using a correction value including error information of the probe 10. It includes.

In the three-phase voltage converter, the same circuit is used for each phase, and may be classified into a resistive voltage divider and an isolation transformer according to a configuration.

In the case of the resistance divider method, the voltage applied from the voltage source obtains the divided output voltage according to the resistance ratio of the resistance divider circuit, and the obtained output voltage is applied to the AFE circuit 42 to be used to calculate the power together with the current signal. . This method is widely used for converting into a voltage signal suitable for the input of the AFE circuit 42. Since the linear characteristic of the resistor is excellent, there is little distortion or phase error of the signal, so that the proper signal conversion characteristic can be obtained with a simple circuit configuration.

Insulated transformer system uses isolation transformer between primary side and secondary side circuit which is directly connected to high voltage to control desired 1 ~ 2 turns and converts into desired signal, so it is easy to block external noise and surge.

The current converter may convert the current applied from the current source into a current value proportional to the number of turns and output the current value. As shown in FIG. 2, the current converter may be a current transformer and may receive an input current I1 from a current source and output an output current I2 inversely proportional to the number of turns N. FIG. The output current I2 can be detected by measuring the voltage across the resistor R connected in parallel. The voltage across the resistor R of the current converter is applied to the AFE circuit 42 and used as a current signal for calculating power. The voltage dividing resistance of the voltage converter and the number of windings of the current converter may vary depending on a range of voltage and current values to be measured by the wattmeter. For example, in the case of a data concentrator that performs the load monitoring function of a transformer, the voltage measurement range is 85 to 260 [V] and the current measurement range is 0 to 760 [A]. Therefore, the data concentrator calculates the measurement error within the normalized voltage and current measurement range, and can output voltage and current satisfying the measurement range and precision in order to perform the error correction function. Voltage and current sources should be connected. However, in the case of the current source, since the maximum output current of the equipment capable of testing the precision is about 200 [A], the number of turns on the input side of the current converter is 4 to 7 so that the standardized current measurement range can be adjusted. . In the case of the voltage source, since a voltage satisfying the standardized voltage measurement range may be output, the circuit may be configured to output the input voltage as it is.

The interface unit 20 fixes the probe 10 of each phase and allows the current source to be wound on the input side of the current converter. In addition, the interface unit 20 secures the output terminal of the probe 10 so that it can be stably connected to the surge / noise protection circuit 30 or the transformer monitoring module 40.

The surge / noise protection circuit 30 may block a surge voltage or a current flowing into the transformer monitoring module 40, and suppress a noise inflow from the outside. The surge / noise protection circuit 30 may be composed of, for example, a circuit combining a film capacitor and an overvoltage protection device, and in order to perform a transformer protection monitoring function of the data concentration device, It can be configured similarly to the elements and circuits installed in the board.

The transformer monitoring module 40 largely calculates load monitoring information such as current, voltage, and power factor by using the output voltage and output current output from the probe 10 and generates a pulse output proportional to the amount of effective and reactive power. And a metering unit 45 for controlling the meter engine unit and integrating the amount of power.

The meter engine unit 41 includes an AFE circuit 42 (Analog Front End) for converting an output voltage and an output current into a digital value, and an amount of current, voltage, power factor, effective and reactive power from the output voltage and output current converted into a digital value. It is composed of a CE (Compute Engine) for calculating the and generates a pulse output proportional to this and at the same time delivers the result to the metering section (45).

The AFE circuit 42 converts an analog signal attenuated at a constant rate through a voltage converter and a current converter into a digital value to perform power measurement and multiplication by a digital software method. The AFE circuit 42 may convert an analog signal into a digital signal according to a reference voltage (Vref) at the time of signal conversion, and may set a reference voltage differently according to characteristics of a signal to be converted. The AFE circuit 42 has a great influence on the characteristics of the electricity meter, and requires careful consideration in circuit design and component arrangement. Since the characteristics may vary greatly depending on the stability of the reference (Vref) voltage during signal conversion, a stable reference voltage may be obtained. Supply is preferred.

The CE 43 (Compute Engine) calculates the current, voltage, power factor, effective and reactive power amount from the voltage and current signal digitally converted in the AFE circuit 42, generates a pulse output proportional thereto, and at the same time, the measurement result. It can be delivered to the metering unit 45 through a serial or parallel communication interface.

The meter engine unit 41 implements measurement algorithms and necessary functions in software on high-performance DSP (Digital Signal Processor) -based hardware and uses various functions performed by the AFE circuit 42 and the CE 43 without changing the hardware. Easy to implement In addition, the meter engine unit may be configured by using a chip dedicated for the electricity meter.

The metering unit 45 performs a function of storing or continuously integrating the measured power information, and the circuit configuration may be divided into the MCU 46, the memory 47, and the RTC 48 circuit for time synchronization.

The MCU 46 manages the overall operation of the transformer monitoring module and receives various power information measured by the meter engine unit 41 to measure weighing data including effective / reactive power, maximum demand power, time-division weighing, power factor, and the like. It generates and operates according to the program content set in advance in the program memory 47.

In addition, the MCU 46 may perform error correction using a correction value including error information of the probe 10, which will be described with reference to FIG. 4.

The memory 47 stores program and metering data for time-based charge application, and may store data even in a power failure by attaching a battery to the nonvolatile memory 47 or SRAM. The memory 47 is preferably independent of the battery at the time of power failure, and may be constituted by Ferroelectric Random Access Memory (FRAM) which is excellent in data retention characteristics and capable of reading / writing the unlimited memory 47.

RTC 48 (Real Time Clock) is a reference time for maintaining data such as time required for the operation of the instrument, managing the weighing schedule according to time zone, changing billing period, applying irregular holidays, calculating leap year, etc. Time synchronization of the electricity meter is performed by generating.

Figure 4 is a connection diagram between the transformer monitoring module correction device and the error test bench according to an embodiment of the present invention.

The error test bench includes a power meter test equipment 200 including a voltage source and a current source, and a calibration terminal device 300.

The output capacity of the voltage source is 1,000 [VA], 2,000 [VA], 4,000 [VA], etc., and it can be mounted in a 19-inch rack. The voltage source produces a varying voltage and no transformer is coupled. The output voltage is stabilized by internal feedback loops and digital control loops for amplitude, phase angle and signal distortion. Harmonics and ripple control can be added to the basic waveform, and internal protection circuitry protects the power supply from overload, open output, mains disconnect and feedback current. Source control is achieved via the optical serial interface, and the ring bus system and synchronization signal interface allow multiple source connections to a multiphase system. The output voltage can be supplied from 30 to 300 [V], and the resolution is preferably 0.01 [%].

The output capacity of the current source is 1,000 [VA], 2,000 [VA], etc., and it is a structure that can be mounted in a 19-inch rack. The current source generates a varying current and the transformer is not coupled. The output current is stabilized by internal feedback loops and digital control loops for amplitude, phase angle and signal distortion. Harmonics can be added to the basic waveforms, and internal protection circuitry protects the power supply from overload, open output, mains shutdown and energy recovery. The output current can be supplied from 1 [mA] to 200 [A], and the resolution is preferably 0.01 [%].

The calibration terminal 300 inputs a command for executing error correction of the transformer monitoring module correcting apparatus 100 connected to the error test stand or monitors various operation states.

The MCU 46 of the transformer monitoring module 40 starts the error correction for the transformer monitoring module from the correction command received from the calibration terminal 300. Algorithms for error correction can, for example, use data from power measurements at two or more phase angles with voltage measurements to calculate correction values, and calculate precision correction values to account for bidirectional metering of the instrument. The correction value may be calculated using the error of power amount measured at 0 °, 60 °, 180 °, and 300 ° of the phase-to-phase phase angle of the phase.

After the correction is completed, the information on the correction value is stored in the memory 47 of the transformer monitoring module, so that the correction can be continuously performed for the module.

As described above, a method of calibrating a wattmeter using an electrostatic source is called an Accurate Source Method. In an embodiment of the present invention, an error of the wattmeter can be corrected using the same. It will be omitted.

However, in one embodiment of the present invention by applying a current source to the primary side of the current converter, and adjusts the current range to be measured in proportion to the number of windings, the transformer monitoring module is the error of the current converter itself, that is, the probe 10 itself In consideration of this, a correction value can be generated. Therefore, the MCU 46 of the transformer monitoring module 40 may perform an error correction in which the error of the probe 10 itself is reflected using the correction value.

5 is a connection diagram between the transformer monitoring module correction device and the error test bench according to another embodiment of the present invention.

A plurality of transformer monitoring module correction device 100 may be mounted on the error test stand, respectively, the transformer monitoring module 40 and the probe 10 of each transformer monitoring module correction device 100 is regarded as one set and error Calibration can be performed. The transformer monitoring module 40 and the probe 10 having the error correction completed are removed from the transformer monitoring module correcting apparatus 100, and a new transformer monitoring module 40 and the probe 10 may be mounted to perform error correction. . Accordingly, the error correction for the plurality of transformer monitoring module 40 may be performed by performing one time error correction, and the transformer monitoring module 40 and the probe 10 are designed to be detachable, so that every error correction is performed. You can skip the process of wiring.

As used in this embodiment, the term " portion " refers to a hardware component such as software or an FPGA (field-programmable gate array) or ASIC, and 'part' performs certain roles. However, 'part' is not meant to be limited to software or hardware. &Quot; to " may be configured to reside on an addressable storage medium and may be configured to play one or more processors. Thus, by way of example, 'parts' may refer to components such as software components, object-oriented software components, class components and task components, and processes, functions, , Subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functions provided in the components and components may be further combined with a smaller number of components and components or further components and components. In addition, the components and components may be implemented to play back one or more CPUs in a device or a secure multimedia card.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

10: Probe
20: interface unit
30: Surge / noise protection circuit
40: transformer monitoring module
41: meter engine
42: AFE (Analog Front End) Circuit
43: CE (Compute Engine)
45: metering unit
46: microcontrol unit (MCU)
47: memory
48: RTC (Real Time Clock)
100: electronic wattmeter correction device
200: power meter test equipment
300: terminal device for correction

Claims (9)

In the transformer monitoring module correction device for calibrating the probe and transformer monitoring module mounted on the data concentration device for AMI (Advanced Metering Infrasturcture) to perform the transformer load monitoring function,
The probe and transformer monitoring module is mounted,
The probe includes a voltage converter that receives a voltage from a voltage source and converts the voltage into a predetermined voltage and outputs a current that is applied from a current source and outputs a current proportional to the number of turns,
The transformer monitoring module detects an output voltage of the voltage converter and an output current of the current converter, and performs an error correction using a correction value including error information of the probe.
The method of claim 1,
The current transformer is a current transformer (CT, Current Transfomer), the transformer is applied to the transformer monitoring module module for outputting the current to the transformer monitoring module, the secondary side is the current source.
3. The method of claim 2,
The number of windings of the current converter is transformer monitoring module correction device having a value of 4 to 7.
The method of claim 1, wherein the transformer monitoring module
A meter engine unit configured to calculate a current, a voltage, and a power factor using the output voltage and the output current output from the probe and to generate a pulse output proportional to an effective and reactive power amount; And
Transformer monitoring module correction device including a metering unit for controlling the meter engine unit and integrating the amount of power.
The method of claim 4, wherein the meter engine unit
AFE (Analog Front End) circuit for converting the output voltage and the output current into a digital value and a pulse output that calculates the current, voltage, power factor value from the output voltage and output current converted into the digital value and is proportional to the amount of effective and reactive power Transformer monitoring module correction device composed of a CE (Compute Engine) to generate and deliver to the metering unit.
The method of claim 5, wherein the metering unit
MCU (Micro for storing current, voltage, and power factor values calculated by CE, integrating effective and reactive power amounts using the pulse output value, and performing error correction using a correction value including error information of the probe. Transformer supervisory module compensator including control unit and memory and real time clock.
3. The method of claim 2,
Fixing the probe and the transformer monitoring module correction device further comprises an interface unit for allowing the current source to be wound on the primary side of the current converter.
3. The method of claim 2,
And a surge / noise protection circuit connected to an input terminal of the transformer monitoring module to prevent a sudden change in the output voltage and the output current and to block noise introduced from the outside.
The method of claim 1,
The transformer monitoring module and the probe is removable transformer monitoring module correction device.

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