KR100987667B1 - Bidirectional electronic watt meter - Google Patents

Abstract

PURPOSE: A bidirectional electronic watt hour meter is provided to efficiently use power by connecting to a smart grid system. CONSTITUTION: A measuring unit(300) produces power data by using a digital signal of an A/D converter. A first memory unit(500) stores power data of the measuring unit. A second memory unit(600) stores error compensation information about the power data stored in the first memory unit. A microcomputer(400) corrects the error of the power data by using error correction information of the second memory unit.

Description

Bidirectional Electronic Watt Meter

The present invention relates to a two-way electronic wattmeter, and more particularly, a bidirectional electronic wattmeter capable of displaying real-time power consumption as well as cumulative power amounts in both directions of transmission and reception, and allowing for specialized error correction according to the characteristics of each operating environment. It is about.

In response to the ever-changing demand for electricity, the power supply company always secures the supply power to maintain a balance between demand and supply, that is, power transmission and generation. In order to balance supply and demand, a power supply company may receive power from another power supply company, for example. If the amount of power transmission increases with the increase of the actual load and the balance with the amount of power generation cannot be maintained, the power supply is received by another power supply company to compensate for the power shortage. In particular, the use of alternative energy, such as solar power, wind power, tidal power, etc., is increasing recently. In this case, electric power is transmitted to and received from each power plant. In this case, the power supply company may receive power from other power supply plants or vice versa. Since the power flow state indicating the power supply and demand state between the power supply companies changes from time to time, the power supply company always checks the state and operates the appropriate power system in accordance with the change in the power flow.

On the other hand, in order to properly operate the power system it is necessary to accurately and quickly the power transmission / reception bi-directional power measurement. However, the conventional electricity meter only displays the accumulated amount of power in one direction, and thus requires an electricity meter displaying real-time amount of power consumed in real time as well as the accumulated amount of power in both the transmission and reception directions. I was using the situation. Therefore, there was a dispute in the calculation of power transmission amount due to the error of each instrument by using a separate power meter for the measurement of power transmission and transmission, and there existed problems in operation due to the installation of a separate meter.

The present invention is to solve the above-mentioned problems of the prior art, an object of the present invention is to display in real time the various amounts of voltage, current, power, such as the amount of power consumed at the moment as well as the cumulative amount of power for the sum and difference of the transmission and reception bi-directional In order to provide a bidirectional electronic electricity meter capable of error correction specialized according to the characteristics of each operating environment.

The bidirectional electronic electricity meter according to the present invention includes a signal detector for detecting and outputting a voltage signal and a current signal proportional to a voltage and a current value from a power line, and converting the voltage signal and current signal values output from the signal detector into digital signals. Measurement unit for calculating data including transmission power, power reception, active power, and reactive power by using the digital signal converted by the A / D conversion unit, voltage, current, transmission power, power reception power, instantaneous power Or a display unit for externally displaying data including active power, a first memory unit for storing data including voltage, current, transmission power, power reception, instantaneous power or active power, and data stored in the first memory unit. A second memory unit for storing preset error correction information, and a data display for calculating data of the measurement unit Control the parameters including the price, and correct the error using the error information stored in the second memory unit data calculated by the measuring unit, calculates the difference between the transmission power and the power receiving power using the corrected data, And a microcomputer for controlling the first memory unit so that data is stored in the first memory unit, or controlling the display unit so that the corrected data is displayed externally through the display unit.

In the bidirectional electronic electricity meter according to the present invention, the measurement unit, an effective power / frequency converter for outputting data in proportion to the effective power amount of each of the power distribution unit or the transmission element on the feed line, the voltage converted by 90 ° phase with respect to the voltage of the feed line A reactive power / frequency converter for outputting data proportional to the amount of reactive power of each of the phase leading or phase delays, and the reactive power / from the data output from the active power / frequency converter and data output from the reactive power / frequency converter. Current flow direction discrimination means for discriminating whether the output of the frequency converter is the power transmission / phase lead, power transmission / phase delay, power supply / phase lead or power reception / phase delay, power to measure the reactive power distinguished according to the output of the current flow direction determination means Characterized in that it comprises a calculation means.

In the bidirectional electronic watt-hour meter according to the present invention, the microcomputer is further characterized by correcting by collectively adding or subtracting the adjustment value using an error value of power measured for a specific current value.

In the bidirectional electronic watt-hour meter according to the present invention, the microcomputer is further characterized by correcting by adding or subtracting each of the adjustment values for each section using an error value of power preset in each current section.

In the bidirectional electronic watt-hour meter according to the present invention, the microcomputer further adjusts the adjustment value collectively by adjusting the continuous value calculated from the change amount of the current versus the change in power error of each current section. It is done.

In the bidirectional electronic electricity meter according to the present invention, a wired / wireless communication unit provided to output an item output through the display unit to the outside by wire or wirelessly, and is connected to the wired / wireless communication unit for transmission power / receiving power and active power. It is another feature that the external storage means for storing the real-time power / cumulative power including / reactive power is further included.

In the bidirectional electronic electricity meter according to the present invention, the error correction information stored in the second memory unit may be reset according to a user-defined error correction value input through the wired / wireless communication unit.

In addition, it is possible to display the total amount of power transmission / receiving effective power by adding the power reception effective power and the transmission power effective amount, and correcting the current section and the error measured at the time of transmission and the current section and the error measured at the time of receiving power, respectively. By calculating the cumulative cumulative amount of power, it is possible to fundamentally prevent disputes in the calculation of power transmission and reception power.

As described in detail above, according to the bidirectional electronic watt-hour meter according to the present invention, not only enables fast and accurate power measurement by performing error correction of various specialized powers according to the characteristics of the operating environment, but also power transmission / receiving power and active power / ineffectiveness. The display means for displaying the power to the outside is capable of proper power operation, and the power transmission / receive power and active power / reactive power can be output through external communication means, so that the efficient power operation in connection with the smart grid system is possible. It is possible.

1 is a diagram illustrating a structure of a bidirectional electronic watt hour meter according to an embodiment of the present invention.
2 is a view showing a measurement unit of the two-way electronic electricity meter according to the present invention.
3 is a diagram illustrating an error characteristic curve of a wattmeter according to an exemplary current change amount.
4 is a diagram illustrating an embodiment of correcting an error in a bidirectional electronic wattmeter according to the present invention.
5A is a diagram illustrating another embodiment of correcting an error in a bidirectional electronic wattmeter according to the present invention.
FIG. 5B is a diagram illustrating a table illustrating error correction information of FIG. 5A.
6A is a diagram illustrating another embodiment of correcting an error in a bidirectional electronic wattmeter according to the present invention.
FIG. 6B is a diagram illustrating a process of calculating the adjustment value in the vector format of FIG. 6A.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

1 is a diagram illustrating a structure of a bidirectional electronic watt hour meter 10 according to an embodiment of the present invention. As shown in FIG. 1, the bidirectional electronic wattmeter 10 detects and outputs a voltage signal and a current signal proportional to voltage and current values from a power line, respectively, and a voltage signal output from the signal detector 100. And voltage, current, transmission power, power receiving power, instantaneous power, or active power using the digital signal converted by the A / D converter 200 and the A / D converter 200 to convert the current signal value into a digital signal. Measurement unit 300 for calculating the power data including, etc., display unit 700 for displaying at least one of the power data including voltage, current, transmission power, power reception, instantaneous power or active power, voltage, current First memory unit 500 for storing power data including transmission power, power reception power, instantaneous power or active power, and second memo for storing error correction information of data stored in the first memory unit. Parameters including the data display interval are controlled to calculate the data of the processor 600 and the measurement unit 300, and the data calculated by the measurement unit is corrected using the error information stored in the second memory unit. Is controlled to be stored in the first memory unit, or the microcomputer 400 for controlling the corrected data to be displayed externally through the display unit. Herein, the power data means all data that can be calculated through the measurement unit, and includes voltage, current, phase of voltage or current, frequency of voltage or current, instantaneous power, accumulated power, active power, reactive power, maximum power, minimum It means all data and calculated power data necessary for calculating power including the integrated power amount of the power, the transmitted power amount or the received power amount, the integrated power amount of the transmitted power amount or the received power amount, or the accumulated power difference accumulated. There may be measured power data not listed in the above power data, but may be added as required by those skilled in the art, and may be selected and adjusted by setting display items for the power data.

The signal detector 100 includes a voltage signal detector 110 and a current signal detector 120 that receive a voltage signal and a current signal proportional to the voltage and the current from the power line, respectively. That is, the voltage signal detector 110 receives the voltage from the power line and steps down the voltage to a range that can be measured by the electricity meter to output a voltage signal proportional to the voltage of the power line. Like the voltage signal detector 110, the current signal detector 120 also outputs a current signal that is proportional to the current of the power line.

A / D (Analog / Digital) converter 200 is composed of a voltage A / D converter 210 and a current A / D converter 220, respectively, the voltage signal detector 110 and the current signal detector 120 Convert the signal received from) into a digital signal. Since the specific operation principle of the voltage signal detector 110 and the current signal detector 120 is a well-known technique, detailed description thereof will be omitted.

As shown in FIG. 2, the measuring unit 300 outputs data in proportion to an effective amount of power of each of the power distribution unit and the transmission unit on the power supply line, as shown in FIG. 2, and a phase conversion of 90 ° with respect to the voltage of the power supply line. Phase conversion means for converting the phase of the reactive power / frequency conversion unit 320, the voltage A / D conversion unit 210 by 90 degrees to output data in proportion to the amount of reactive power of each of the phase leading or phase delay by using the prepared voltage 330, the output of the reactive power / frequency converter from the data output from the active power / frequency converter and the data output from the reactive power / frequency converter is the transmission / phase advance, transmission / phase delay, faucet / phase lead or faucet Flow direction determination means 340 for distinguishing whether or not phase delay, and the data including the transmission power, power reception power, instantaneous power and active power according to the output of the flow direction determination means Depending on the power calculation unit 340 and the output of the direction control means is a bird comprising: a power calculating means 350 for calculating the power that is distinct.

The active power / frequency converting means 310 multiplies the voltage and the current which are digitally converted and output through the voltage A / D converting unit 210 and the current A / D converting unit 220, respectively, and calculates a power value to calculate the power value. Transfer to the discriminating means 340.

The reactive power / frequency converting unit 320 is a voltage and current A / D converting unit which is a digitally converted value obtained by converting the voltage of the voltage A / D converting unit 210 by 90 ° using the phase converting unit 330. The power value is calculated by multiplying the current, which is a digitally converted value output through 220, and transmitted to the current direction determining unit 340.

The flow direction determining means 340 may receive the output of the active power / frequency conversion means 310 and the reactive power / frequency conversion means 320 to determine whether the transmission / reception power and the amount of reactive power and active power. Since the detailed principle thereof is described in Japanese Patent No. 3544466, detailed description thereof will be omitted.

The power calculating means 350 calculates real-time or cumulative power by receiving active power, reactive power, and transmission / receiving power values determined from the flow direction determination means 340. A buffer or memory may be further included therein to calculate the cumulative power. In addition, the power calculation means may separately calculate the active power, reactive power, transmission power and power reception power value separately, and the separately calculated value is transferred to the microcomputer 400 to be described later, and the first memory unit undergoes an error correction process. 500 may be stored.

The microcomputer 400 controls various parameters of the bidirectional electronic watt hour meter 10 according to the present invention. That is, the data display interval of the measurement unit 300 is controlled, and errors that may occur in data measurement may be corrected. The error correction is performed by comparing the measured voltage, the measured current, and various measured power information stored in the first memory unit 500 with the error correction information stored in the second memory unit 600 to calculate an adjustment value for the measured value. This is done by adding or subtracting the adjusted value to the actual value.

3 is a diagram illustrating an error characteristic curve of a wattmeter according to an exemplary current change amount. The horizontal axis represents an operating condition according to the load current, and the vertical axis represents an error (shown as an offset in the drawing) between the power value calculated according to the current measured from the A / D converter 200 and the actually measured power value. As shown in FIG. 4, the error exists in the entire section of the current measured by the A / D converter 200. The specific error correction method is as follows.

As a first example of correcting an error, there is a method of collectively correcting an error of data as illustrated in FIG. 4. In other words, by adjusting the error value of the power measured for a specific operating condition as an adjustment value, the adjustment value is collectively added or subtracted and corrected. Specific operating conditions may be arbitrarily set by a user or may be set according to a separate standard rule. According to this embodiment, the measurement of power and the error correction speed of the measured power are fast. Such an embodiment may be used when the electricity meter operates under a specific operating environment.

As a second embodiment, as shown in FIG. 5A, there is a method of correcting an error value of power using a preset data table for various operating conditions represented by a load current. An example of a data table is shown in FIG. 5B and such error correction data can be calculated by repeated experiments.

The application section of FIG. 5B is based on current, and a, b, c, d, e, etc. refer to a load current, which means respective operating conditions. The unit is not specified separately and may take a general constant value or may be a numerical value recognized by the microcomputer 400.

The error adjustment value (shown as Offset in the drawing) when the power is transmitted according to the current section can be obtained by comparing the error data for each current range with the standard electricity meter used for the error correction of the bidirectional electronic electricity meter and the electricity meter. In an embodiment of the present invention, A, B, C, and D are A, B, C, and D in the sections AB, bc, cd and de, respectively. ?, B ??, C ??, D ?? and the unit is not specified separately and may take a general constant value or may be a numerical value recognized by the microcomputer 400. That is, if the current value at the time of receiving the value of the ab section, the error is A ', so the microcomputer 400 corrects the amount of effective power measured by the measurement unit 300 by the error A' and stores it in the first memory unit 500. The amount of effective power at the time of power reception is displayed on the display unit 700, and the calculated power amount is displayed on the calculation unit display unit by reflecting the value corrected in real time on the total amount of power transmission and reception. This process applies to both transmission and transmission, and can be applied to other types of power value calculation processes as well as the active power calculation process. According to this embodiment, it is possible to secure the precision of the meter by adjusting the number of measurements, and there is an advantage in that it is possible to secure stable precision even if the magnitude of power before and after transmission is different.

As a third embodiment, there is a method of correcting data in a vector manner as shown in FIG. 6A. The calculation of the vector is shown in FIG. 6B, and when the section a-b of FIG. 6A is exemplarily described, an adjustment value of the vector type calculated from the change amount of the load current versus the change amount of the power error in the section may be calculated. When the adjustment value of the vector type is calculated, the corrected power data may be calculated by adding or subtracting the calculated adjustment value of the vector type in each load current section. Using this embodiment, it is possible to secure high data reliability with a relatively small number of measurements. Such an embodiment may be used when there is a certain tendency in the characteristics of the meter and the environmental change is not large after the installation of the bidirectional electronic electricity meter.

On the other hand, the bidirectional electronic watt-hour meter according to the present invention converts the measured voltage signal and current signal into a digital signal as it is without additional processing, so that the correction of the converted digital signal is also possible digitally, so the correction speed is fast. In particular, when the difference between the transmission power and the receiving power is large and there is a large current change, the error of the measurement of the transmission power can be prevented early by correcting the error of each power transmission and summing and displaying the cumulative transmission power.

The display unit 700 displays the voltage, current, transmission power, power reception, instantaneous power, or accumulated power up to a specific time point measured by the bidirectional electronic electricity meter 10 according to the present invention. , Power consumption and battery status can be displayed. In addition, not only the accumulated power but also the instantaneously consumed power can be displayed in real time, and the power can be displayed in incremental form by adding the amount of power received externally by time and the amount of power transmitted externally through self-generation. As a result, it is possible to monitor the exact amount of power related to power demand by time of day.

On the other hand, the bi-directional electronic electricity meter 10 according to the present invention may further include a wired / wireless communication unit 800 that enables to output the item output through the display unit 700 through an external terminal (not shown). have. The wire / wireless communication unit 800 includes a wired communication means and a wireless communication means, and RS-232 / 485, DCPLC, PLC, NFC, etc. may be used as the wired communication means, and WiFi, Zigbee, Bluetooth, It can be used with CDMA / GSM, 3G, and LTE.

In addition, the information of the two-way electronic electricity meter 10 collected by wired or wireless may be linked with an external monitoring system as part of a smart grid system, and real-time and cumulative power usage by supporting a separate external storage means for the wired / wireless communication means. Information can be stored at the same time. As the power usage information, the aforementioned transmission power / receive power, active power / reactive power, and the like may be displayed.

In addition, the bidirectional electronic watt hour meter 10 may reset error correction information stored in the second memory unit 600 according to a user-defined error correction value input through the wired / wireless communication unit 800.

As an example, the error correction value that may be reset may be changed as characteristics of the voltage signal detector 110 and the current signal detector 120 of the bidirectional electronic wattmeter 10 increase, resulting in an error in the measured value. It may be a correction value.

Herein, the degradation correction means that the characteristics of the voltage signal detector 110 and the current signal detector 120 are changed as the service period increases, thereby degrading the input signal from the initial set value and correcting the initial set value. Means that.

The deterioration correction value may be calculated through repeated experiments at the manufacturer, and the correction value may be calculated differently according to the used period of the bidirectional electronic wattmeter 10. The calculated degradation compensation value may be input through the wired / wireless communication unit 800. As a method of inputting the degradation compensation value calculated through the wire / wireless communication unit 800, a well-known publicly known technology may be used.

The input deterioration correction value is transferred to the microcomputer 400 and used to reset the error correction value stored in the second memory unit 600 in the microcomputer 400. When the error correction value is reset, the reset error correction value is again stored in the second memory unit 600. The reset error correction value and the error correction information may be confirmed through the display unit 700.

The error correction value reset of the plurality of bidirectional electronic wattmeters 10 may be performed for all installed bidirectional electronic wattmeters 10, and may be performed for each bidirectional electronic wattmeter 10 installed in a specific region, as well as for each It may be performed separately for each bidirectional electronic watt hour meter 10.

In the above description of the preferred embodiment of the present invention by way of example, the scope of the present invention is not limited to this specific embodiment, and those skilled in the art within the scope of the claims of the present invention Changes may be made as appropriate.

10: electronic power meter 100: signal detector
110: voltage signal detector 120: current signal detector
200: A / D converter 210: voltage A / D converter
220: current A / D conversion unit 300: measurement unit
310: active power / frequency converting means 320: reactive power / frequency converting means
330: phase shift means 340: flow direction determination means
350: power calculation means 400: microcomputer
500: first memory unit 600: second memory unit
700: display unit 800: wired / wireless communication unit

Claims (8)

A signal detector for detecting and outputting a voltage signal and a current signal proportional to the voltage and current values, respectively, from the power line;
An A / D converter converting the voltage signal and the current signal output from the signal detector into a digital signal;
A measuring unit calculating power data using the digital signal converted by the A / D converter;
A display unit for displaying the power data calculated by the measurement unit;
A first memory unit for storing the power data calculated by the measurement unit;
A second memory unit for storing error correction information on power data stored in the first memory unit;
The error data is corrected with respect to the power data using the error data stored in the second memory unit based on the power data calculated by the measuring unit, and the difference is calculated with respect to the amount of power transmission and reception power among the corrected power data. A microcomputer controlling the first memory unit to store the corrected power data in a first memory unit, and controlling the display unit to display the corrected power data externally through the display unit;
Two-way electronic electricity meter, comprising a.
The method of claim 1,
The microcomputer,
The amount of power obtained by summing the difference between the total amount of power transmission power and the total amount of power receiving power is calculated using the corrected power data, and the difference between the calculated total amount of power transmission power and the total amount of power receiving power is displayed externally through the display unit. And a bidirectional electronic watt-hour meter for controlling the display unit. The method of claim 2,
The measurement unit,
An active power / frequency converter for outputting data proportional to the amount of active power of each of the power distribution element and the transmission element on the feed line;
A reactive power / frequency converter for outputting data proportional to the amount of reactive power of each of the phase leading or phase delay using a voltage 90 ° phase-converted with respect to the voltage of the feeder;
From the data output from the active power / frequency converter and the data output from the reactive power / frequency converter, the output of the reactive power / frequency converter is transmitted / phase leading, power transmitting / phase delaying, power receiving / phase leading, or power receiving / phase delaying. Bird direction discrimination means for discriminating recognition;
Power calculation means for respectively metering reactive power distinguished according to the output of the flow direction discrimination means;
Two-way electronic electricity meter, characterized in that configured to include.
The method according to any one of claims 1 to 3,
The microcomputer,
A bidirectional electronic watt-hour meter, characterized in that by adjusting the error value of the power measured with respect to a specific current value as a adjustment value collectively.
The method according to any one of claims 1 to 3,
The microcomputer,
The bidirectional electronic watt-hour meter, characterized in that the correction value is added or subtracted for each section by adjusting the error value of the preset power for each current section.
The method according to any one of claims 1 to 3,
The microcomputer,
A bidirectional electronic watt-hour meter, characterized in that the adjustment value is collectively added or subtracted using a continuous value calculated from a change amount of current versus a change in power error of each current section.
The method according to any one of claims 1 to 3,
A wired / wireless communication unit provided to output an item output through the display unit to the outside in a wired or wireless manner;
External storage means connected to the wired / wireless communication unit to store real-time power / cumulative power including transmission power / receiving power and active power / reactive power;
Two-way electronic wattmeter characterized in that it further comprises.
The method of claim 7, wherein
And the error correction information stored in the second memory unit may be reset according to a user-defined error correction value input through the wired / wireless communication unit.

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