WO2012002615A1 - Power quality monitoring system and method thereof - Google Patents

Power quality monitoring system and method thereof Download PDF

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Publication number
WO2012002615A1
WO2012002615A1 PCT/KR2010/006380 KR2010006380W WO2012002615A1 WO 2012002615 A1 WO2012002615 A1 WO 2012002615A1 KR 2010006380 W KR2010006380 W KR 2010006380W WO 2012002615 A1 WO2012002615 A1 WO 2012002615A1
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Prior art keywords
waveform
voltage
current
representative
power quality
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PCT/KR2010/006380
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French (fr)
Korean (ko)
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박용업
김상준
이건행
최성훈
이병성
최선규
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한국전력공사
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Publication of WO2012002615A1 publication Critical patent/WO2012002615A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
    • G01R19/2513—Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging

Definitions

  • the present invention relates to a power quality monitoring system and method thereof.
  • An object of the present invention is to provide a power quality monitoring system and method capable of managing power quality by monitoring harmonics generated in a power system.
  • the present invention is to provide a power quality monitoring system and method that can significantly improve the operation speed for harmonic evaluation of the power system due to the reduction of the sampling data.
  • a power quality monitoring system is provided.
  • the power quality monitoring system is connected to the bus and distribution lines of the power system, acquires voltage waveforms from each of the bus and distribution lines at set time intervals, samples the acquired voltage and current waveforms at set intervals, and samples them for a set measurement period.
  • a power quality measuring device for generating and transmitting a voltage representative waveform and a current representative waveform by superimposing the obtained voltage waveform and the current waveform in one cycle;
  • a server that decomposes the voltage representative waveform and the current representative waveform into harmonic components through a fast Fourier transform, respectively, and analyzes the harmonic components to monitor an abnormal occurrence of the power system.
  • the power quality monitoring method includes acquiring a voltage waveform and a current waveform at predetermined time intervals from each of the bus and distribution lines of the power system; Sampling each of the acquired voltage and current waveforms at a set period; Generating a voltage representative waveform and a current representative waveform by superimposing each of the voltage waveform and the current waveform sampled for a set measurement period in one cycle; And analyzing the voltage representative waveform and the current representative waveform by FFT converting.
  • the representative value means the RMS calculated value corresponding to the period specified by the user by performing the FFT calculation in 12 cycles prescribed by IEC.
  • the FFT is calculated in units of 12 cycles to calculate a representative value.
  • the sampled waveforms in units of 12 cycles are successively superimposed. After that, sampling and waveform superimposition are performed at a 128 or 256 sampling rate or more per cycle for a period specified by the user, and a representative waveform is calculated by a representative value period according to the power provider's policy. Accordingly, the power quality monitoring system according to an embodiment of the present invention has improved accuracy and reliability compared to the prior art.
  • the calculation of the representative waveform and the FFT conversion calculation of the representative waveform are performed in the power quality measuring apparatus and the server.
  • the power quality measurement device only needs to transmit a representative waveform to the server, thereby reducing the computational load and the network load.
  • the server may perform the FFT at the time desired by the user. Accordingly, the power quality monitoring system according to an embodiment of the present invention is easily scalable and the measurement stop is simplified.
  • the power quality monitoring system separates the measurement items for each outgoing line of the bus and distribution lines to measure voltage waveforms and current waveforms for each of the periphery transformers of the substation, thereby enabling comprehensive management of power quality.
  • the number of channels for waveform measurement is reduced. Accordingly, the power quality monitoring system of the present invention is significantly reduced in construction cost compared to the conventional power quality monitoring system.
  • FIG. 1 is a view showing a power quality monitoring system according to an embodiment of the present invention.
  • FIG. 2 is a diagram illustrating a configuration of an apparatus for measuring power quality according to an embodiment of the present invention.
  • FIG. 3 is a diagram illustrating a representative waveform corresponding to a voltage waveform and a current waveform according to an embodiment of the present invention.
  • FIG. 4 is a diagram illustrating a server according to an exemplary embodiment.
  • FIG. 5 is a flowchart illustrating a method of measuring power quality by an apparatus for measuring power quality according to an embodiment of the present invention.
  • first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.
  • FIG. 1 is a view showing a power quality monitoring system according to an embodiment of the present invention.
  • the power quality monitoring system 10 may include a representative waveform generated by the power quality measuring apparatus 100 and the power quality measuring apparatus 100 connected to the power system 20. And a server 200 that receives the fast Fourier transform (FFT) operation.
  • FFT fast Fourier transform
  • the power system 20 consists of a three-phase four-wire system.
  • the power system 20 includes a bus bar 50 and a distribution line 60 connected to the peripheral pressure transformer (MTR) 40 of the substation 30.
  • the main transformer 50 is provided with a phase transformer (PT) 70 for each phase.
  • a current transformer (CT) 80 is installed in each phase in the distribution line 60.
  • the power quality measuring apparatus 100 may be installed in units of banks of the bus bar 50 connected to the peripheral voltage transformer 40 of the substation 30, or may be connected to the bus bar 50 of the power system 20.
  • the power distribution line 60 may be connected to the withdrawal points, but is not limited thereto.
  • the power quality measuring apparatus 100 acquires a voltage waveform and a current waveform at time intervals set through three phase voltage channels of the bus line 50 and four current channels of each distribution line 60. Next, the power quality measuring apparatus 100 samples the acquired waveform according to a set method to generate a representative waveform, that is, a voltage representative waveform and a current representative waveform. In addition, the power quality measurement apparatus 100 transmits the generated voltage representative waveform and current representative waveform to the server 200.
  • the server 200 converts the received representative waveform into a preset method and analyzes the converted result to check whether there is an abnormality in the power system 20.
  • the server 200 receives and stores a voltage representative waveform and a current representative waveform from the power quality measuring apparatus 100. Next, the server 200 analyzes the voltage waveform and the current waveform by converting the voltage representative waveform and the current representative waveform according to a predetermined method, for example, an FFT operation. At this time, the server 200 performs decomposition and the like of the waveform for each harmonic order to perform various analysis and evaluation on the power system 20. Through this, the server 200 may check whether there is an abnormality of the power system 20.
  • a predetermined method for example, an FFT operation
  • FIG. 2 is a diagram illustrating a configuration of an apparatus for measuring power quality according to an embodiment of the present invention.
  • 3 is a diagram illustrating a representative waveform corresponding to a voltage waveform and a current waveform according to an embodiment of the present invention.
  • the power quality measuring apparatus 100 may include a pickup unit 110, a sampling unit 120, a waveform generator 130, a first storage unit 140, and a transmission unit.
  • the unit 150 is included.
  • the pickup unit 110 acquires the voltage waveform and the current waveform of the power system 20 to which the power quality measuring apparatus 100 is connected at predetermined time intervals. For example, the pickup unit 110 acquires the voltage waveform and the current waveform of the power system at a time interval set at 1 second, 3 seconds, 10 minutes or 30 minutes.
  • the method for acquiring the voltage waveform and the current waveform of the power system is obvious to those skilled in the art, and thus a separate description thereof will be omitted.
  • the sampling unit 120 samples the voltage waveform and the current waveform acquired by the pickup unit 110 at a predetermined period and converts the waveform into a digital waveform.
  • the sampling unit 120 may sample the voltage waveform and the current waveform acquired through the pickup unit 110 at intervals (n is a natural number of 7 or more).
  • the sampling period of the voltage waveform and the current waveform in the sampling unit 120 is called a sampling period.
  • harmonic voltage of MV system regulated by IEC is defined to manage up to 50 orders, at least 128 cycles or 256 cycles are required for harmonic component resolution. If the sampling unit 120 samples with a sampling period of less than 128 cycles, it may be difficult to obtain accurate harmonic information up to 50 orders. Accordingly, in the present specification, it is assumed that the sampling cycle is 128 or more cycles.
  • the sampling unit 120 stores the voltage and current waveforms sampled according to the designated sampling period in the first storage unit 140.
  • the waveform generator 130 generates a voltage representative waveform and a current representative waveform by overlapping and adding the sampled voltage waveform and the current waveform in one cycle during a preset measurement period.
  • the voltage representative waveform or the current representative waveform may be generated as shown in FIG. 3.
  • the waveform generator 130 may each of the sampled voltage waveforms or current waveforms, such as the first sampling waveform 310, the second sampling waveform 320, and the third sampling waveform 330 illustrated in FIG. 3. By superimposing in one cycle, the values of the same sampling period are summed to generate a voltage representative waveform or a current representative waveform.
  • the measurement cycle is the maximum demand period in order to facilitate understanding and explanation.
  • the measurement period may be set to 15 minutes.
  • the measurement period may be set to a period other than the maximum demand period, such as 3 minutes, 10, and so on.
  • the waveform generator 130 may generate the voltage representative waveform and the current representative waveform by overlapping and summing the sampled voltage and current waveforms in one cycle during the measurement period, and calculating their average values.
  • the waveform generator 130 may generate a voltage representative waveform and a current representative waveform by superimposing / summing voltage and current waveforms having the same sampling period with respect to the voltage and current waveforms sampled during the measurement period.
  • the cycles of the voltage representative waveform and the current representative waveform are superimposed by overlapping each cycle into one cycle for the sampled voltage and current waveforms of the power quality measurement apparatus 100.
  • the amount of sampled data can be reduced.
  • the voltage waveform and the current waveform in the power system 20 do not change drastically unless an internal or external event occurs such as a power failure due to an accident, a failure, a voltage drop, a lightning strike, or a surge due to the opening and closing of a switch.
  • the power quality measuring apparatus 100 may generate a voltage representative waveform and a current representative waveform for the voltage and current waveforms sampled during the measurement period, and transmit the generated voltage representative waveform and the current representative waveform to the remote server 200. have.
  • the server 200 may calculate harmonics by calculating sample data corresponding to half periods of the voltage representative waveform and the current representative waveform received from the power quality measuring apparatus 100.
  • the first storage unit 140 accumulates and stores voltage and current waveforms sampled through the sampling unit 120 during a measurement period. In addition, the first storage unit 140 stores an algorithm required to operate the power quality measuring apparatus 100 according to an embodiment of the present invention.
  • the transmitter 150 transmits the voltage representative waveform and the current representative waveform generated by the waveform generator 130 to the remote server 200.
  • FIG. 4 is a diagram illustrating a server according to an exemplary embodiment.
  • the server 200 includes a receiver 210, a second storage unit 220, and a calculator 230.
  • the receiver 210 receives a voltage representative waveform and a current representative waveform from the power quality measuring apparatus 100.
  • the second storage unit 220 stores the voltage representative waveform and the current representative waveform received from the power quality measuring apparatus 100.
  • the second storage unit 220 may be formed in the form of a database that stores the voltage representative waveform and the current representative waveform.
  • the calculation unit 230 analyzes the voltage waveform and the current waveform of the power system 20 by FFTing the voltage representative waveform and the current representative waveform according to a preset method.
  • the calculation unit 230 calculates harmonic evaluation values by performing decomposition of waveforms according to harmonic orders.
  • the calculation unit 230 performs various analysis and evaluation on the power system 20 using the calculated evaluation value. Through this, the server 200 may check whether there is an abnormality of the power system 20.
  • the calculation unit 230 may perform the FFT conversion only when the user's instruction is input, and analyze the voltage waveform and the current waveform.
  • the power quality monitoring system Compared with the conventional power quality monitoring system, the power quality monitoring system according to an embodiment of the present invention reduces the calculation period of the representative value.
  • the representative value means a root mean square (RMS) calculated value corresponding to a period designated by a user by performing an FFT operation in units of 12 cycles prescribed by IEC.
  • the FFT is calculated in units of 12 cycles in order to calculate a representative value.
  • the user continuously after overlapping the sampled waveforms in units of 12 cycles.
  • the power quality monitoring system according to an embodiment of the present invention has improved accuracy and reliability compared to the prior art.
  • the representative waveform and the FFT calculation of the representative waveform are divided in the power quality measuring apparatus and the server.
  • the power quality measurement device only needs to transmit a representative waveform to the server, thereby reducing the computational load and the network load.
  • the server may perform an FFT operation at a time desired by the user. Accordingly, the power quality monitoring system according to an embodiment of the present invention is easily scalable and the measurement stop is simplified.
  • the power quality monitoring system separates the measurement items for each outgoing line of the bus and distribution lines to measure voltage waveforms and current waveforms for each of the periphery transformers of the substation, thereby enabling comprehensive management of power quality.
  • the number of channels for waveform measurement is reduced. Accordingly, the power quality monitoring system of the present invention is significantly reduced in construction cost compared to the conventional power quality monitoring system.
  • FIG. 5 is a flowchart illustrating a method of measuring power quality by an apparatus for measuring power quality according to an embodiment of the present invention.
  • the power quality measuring apparatus 100 acquires a voltage waveform and a current waveform at time intervals set through three channels of phase voltages of the power line 50 and the power grid and four channels of current of each power distribution line 60 (S10).
  • the power quality measuring apparatus 100 is connected to the bus and distribution lines of the power system to acquire phase 3-channel voltage waveforms of the bus and 4-channel current waveforms of each distribution line at predetermined times.
  • the power quality measuring apparatus 100 receives a three-channel voltage for each phase from an instrument transformer installed in a bus, and acquires a voltage waveform.
  • the power quality measuring apparatus 100 receives a four-channel current from the current transformer for the instrument installed in each distribution line to obtain a current waveform.
  • the power quality measuring apparatus 100 samples the acquired voltage and current waveforms at a predetermined sampling period and stores them (S20). Since this is the same as described above, overlapping description thereof will be omitted.
  • the power quality measuring apparatus 100 generates a voltage representative waveform and a current representative waveform by superimposing the sampled voltage and current waveforms in one cycle during the measurement period (S30). For example, the power quality measuring apparatus 100 may overlap the sampled voltage and current waveforms in one cycle, calculate an average value thereof, and generate a voltage representative waveform and a current representative waveform using the averaged values.
  • the power quality measuring apparatus 100 transmits the generated voltage representative waveform and current representative waveform to the server 200 (S40).
  • the server 200 performs an FFT operation on the received voltage representative waveform and current representative waveform. Through this, the server analyzes the voltage representative waveform and the current representative waveform (S50). The server 200 calculates harmonic evaluation values by performing decomposition of waveforms according to harmonic orders. The server 200 performs various analysis and evaluation on the power system using the calculated evaluation value. Through this, the server checks whether the power system is abnormal.

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  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Remote Monitoring And Control Of Power-Distribution Networks (AREA)

Abstract

The present invention relates to a power quality monitoring system and method thereof. The power quality monitoring system includes a power quality measuring device and a server. The power quality measuring device is connected to a bus and a distribution line of a power system to obtain a voltage waveform from each of the bus and the distribution line at a set time interval, samples the obtained voltage waveform and current waveform in a set period, and overlaps the voltage waveform and the current waveform sampled for a set measurement period into one cycle to generate and transmit a representative voltage waveform and a representative current waveform. The server decomposes a representative voltage waveform and a representative current waveform into a harmonic wave component through Fast Fourier Transform (FFT) and monitors abnormal occurrences in a power system by analyzing the harmonic wave component.

Description

전력 품질 모니터링 시스템 및 그 방법Power quality monitoring system and method
본 발명은 전력 품질 모니터링 시스템 및 그 방법에 관한 것이다.The present invention relates to a power quality monitoring system and method thereof.
산업 설비들이 대형화 되면서 고조파나 플리커를 대량으로 발생시키는 경우가 생겨나고 있어서, 정전이 아닌데도 전압이 순간적으로 강하하고, 고조파가 발생하여 예민한 특성을 가진 전기기기를 사용하는 수용가의 경우 순간적으로 전기기기의 동작이 정지되는 등 전기 품질과 관련된 현상이 빈번하게 발생하고 있다.As industrial facilities become larger, there are cases where a large amount of harmonics or flickers are generated.In the case of a consumer who uses an electric device having a sensitive characteristic because the voltage drops momentarily and harmonics occur even when the power is not outage, The phenomenon related to electrical quality frequently occurs, such as the operation is stopped.
현재 국내의 경우에는 국제 전기 표준 회의(IEC: International Electrotechnical Commission)의 규격에 근거하여 전기품질 관련규격을 제정 및 개정하고 있다. IEC 규격에 의하면 전기품질 평가를 위한 측정은 수용가 인입점(Point of common coupling, PCC)에서 수행해야 한다. 이럴 경우 전력회사는 전기품질을 관리하기 위해서 모든 수용가 인입점에 PQMS(Power Quality Monitoring System)을 구축해야 하고, 관련규격에 적합한 데이터를 취득하기 위한 연산속도 및 정밀도를 고려하면 매우 고가의 장비가 필요하게 된다. 따라서 고가의 구축비용 및 관리대상 개소가 너무 많아 전력회사에서는 PQMS을 이용한 상시 모니터링이 어렵다.Currently, in Korea, the electrical quality standards are enacted and revised based on the standards of the International Electrotechnical Commission (IEC). According to the IEC standard, measurements for the evaluation of electrical quality should be carried out at the point of common coupling (PCC). In this case, the utility company needs to establish a power quality monitoring system (PQMS) at every customer entry point to manage the electrical quality, and requires very expensive equipment in consideration of the calculation speed and precision to obtain data suitable for the relevant standard. Done. As a result, expensive construction costs and management points are so high that it is difficult for power companies to monitor PQMS at all times.
본 발명은 전력 계통에서 발생하는 고조파를 모니터링하여 전력 품질을 관리할 수 있는 전력 품질 모니터링 시스템 및 방법을 제공하기 위한 것이다.An object of the present invention is to provide a power quality monitoring system and method capable of managing power quality by monitoring harmonics generated in a power system.
또한, 본 발명은 샘플링 자료의 축소로 인해 전력계통의 고조파 평가를 위한 연산 속도를 획기적으로 향상시킬 수 있는 전력 품질 모니터링 시스템 및 방법을 제공하기 위한 것이다.In addition, the present invention is to provide a power quality monitoring system and method that can significantly improve the operation speed for harmonic evaluation of the power system due to the reduction of the sampling data.
본 발명의 일 측면에 따르면, 전력 품질 모니터링 시스템을 제공한다.According to an aspect of the present invention, a power quality monitoring system is provided.
전력 품질 모니터링 시스템은 전력 계통의 모선 및 배전 선로에 연결되어 설정된 시간 간격으로 상기 모선 및 상기 배전 선로 각각에서 전압 파형을 취득하고, 취득한 전압 파형 및 전류 파형을 설정된 주기로 샘플링하여, 설정된 측정 주기 동안 샘플링된 전압 파형 및 전류 파형을 하나의 사이클로 중첩시켜 전압 대표 파형 및 전류 대표 파형을 생성하여 전송하는 전력 품질 측정 장치; 및 상기 전압 대표 파형 및 상기 전류 대표 파형을 각각 고속 푸리에 변환을 통해 고조파 성분으로 분해하고, 상기 고조파 성분을 분석하여 상기 전력 계통의 이상 발생을 감시하는 서버를 포함한다.The power quality monitoring system is connected to the bus and distribution lines of the power system, acquires voltage waveforms from each of the bus and distribution lines at set time intervals, samples the acquired voltage and current waveforms at set intervals, and samples them for a set measurement period. A power quality measuring device for generating and transmitting a voltage representative waveform and a current representative waveform by superimposing the obtained voltage waveform and the current waveform in one cycle; And a server that decomposes the voltage representative waveform and the current representative waveform into harmonic components through a fast Fourier transform, respectively, and analyzes the harmonic components to monitor an abnormal occurrence of the power system.
본 발명의 다른 측면에 따르면, 전력 품질 모니터링 방법을 제공한다.According to another aspect of the present invention, there is provided a power quality monitoring method.
전력 품질 모니터링 방법은 전력 계통의 모선 및 배전 선로 각각으로부터 설정된 시간 간격으로 전압 파형 및 전류 파형을 취득하는 단계; 취득한 전압 파형 및 전류 파형 각각을 설정된 주기로 샘플링하는 단계; 설정된 측정 주기 동안 샘플링된 상기 전압 파형 및 상기 전류 파형 각각을 하나의 사이클로 중첩하여 전압 대표 파형 및 전류 대표 파형을 생성하는 단계; 및 상기 전압 대표 파형 및 상기 전류 대표 파형을 FFT 변환하여 분석하는 단계를 포함한다.The power quality monitoring method includes acquiring a voltage waveform and a current waveform at predetermined time intervals from each of the bus and distribution lines of the power system; Sampling each of the acquired voltage and current waveforms at a set period; Generating a voltage representative waveform and a current representative waveform by superimposing each of the voltage waveform and the current waveform sampled for a set measurement period in one cycle; And analyzing the voltage representative waveform and the current representative waveform by FFT converting.
본 발명의 일 실시 예에 따른 전력 품질 모니터링 시스템은 대표값의 산출 주기가 감소한다. 여기서 대표값은 IEC에서 규정하는 12 싸이클 단위로 FFT 연산을 수행하여 사용자가 지정하는 기간에 해당되는 RMS 산출값을 의미한다. 종래의 전력 품질 모니터링 시스템은 대표값을 산출하기 위해 12 싸이클(cycle) 단위로 FFT를 연산하였으나, 본 발명의 일 실시 예에 따른 전력 품질 모니터링 시스템에서는 12 싸이클 단위의 샘플링된 파형을 연속적으로 중첩시킨 후 사용자가 지정하는 기간 동안 1 싸이클 마다 128 또는 256 샘플링 비율 이상으로 샘플링 및 파형 중첩을 수행하고, 전력 공급자의 정책에 따른 대표값 주기에 의해 대표 파형을 산출한다. 이에 따라 본 발명의 일 실시 예에 따른 전력 품질 모니터링 시스템은 종래에 비해 정밀도 및 신뢰도가 향상된다. In the power quality monitoring system according to an exemplary embodiment of the present invention, a calculation cycle of the representative value is reduced. Here, the representative value means the RMS calculated value corresponding to the period specified by the user by performing the FFT calculation in 12 cycles prescribed by IEC. In the conventional power quality monitoring system, the FFT is calculated in units of 12 cycles to calculate a representative value. However, in the power quality monitoring system according to an embodiment of the present invention, the sampled waveforms in units of 12 cycles are successively superimposed. After that, sampling and waveform superimposition are performed at a 128 or 256 sampling rate or more per cycle for a period specified by the user, and a representative waveform is calculated by a representative value period according to the power provider's policy. Accordingly, the power quality monitoring system according to an embodiment of the present invention has improved accuracy and reliability compared to the prior art.
또한, 본 발명의 일 실시 예에 따른 전력 품질 모니터링 시스템은 대표 파형의 산출 및 대표 파형의 FFT변환 연산이 전력 품질 측정 장치와 서버에서 나누어 수행된다. 전력 품질 측정 장치는 서버로 대표 파형만 전송하면 되므로 연산에 따른 부하와 네트워크 부하를 줄일 수 있다. 그리고 서버는 사용자가 원하는 시간대에 FFT를 수행할 수 있다. 이에 따라 본 발명의 일 실시 예에 따른 전력 품질 모니터링 시스템은 확장성이 용이하고 측정 정차가 간소해진다.In addition, in the power quality monitoring system according to an embodiment of the present invention, the calculation of the representative waveform and the FFT conversion calculation of the representative waveform are performed in the power quality measuring apparatus and the server. The power quality measurement device only needs to transmit a representative waveform to the server, thereby reducing the computational load and the network load. In addition, the server may perform the FFT at the time desired by the user. Accordingly, the power quality monitoring system according to an embodiment of the present invention is easily scalable and the measurement stop is simplified.
또한, 본 발명의 일 실시 예에 따른 전력 품질 모니터링 시스템은 모선 및 배전 선로의 인출 선로별 측정 항목을 별도로 분리하여 변전소의 주변압기별로 전압 파형과 전류 파형을 측정하므로 전력 품질의 종합적인 관리가 가능하고, 파형 측정을 위한 채널수가 감소된다. 이에 따라 본원 발명의 전력 품질 모니터링 시스템은 구축 비용이 종래의 전력 품질 모니터링 시스템과 비교하여 대폭 감소한다.In addition, the power quality monitoring system according to an embodiment of the present invention separates the measurement items for each outgoing line of the bus and distribution lines to measure voltage waveforms and current waveforms for each of the periphery transformers of the substation, thereby enabling comprehensive management of power quality. The number of channels for waveform measurement is reduced. Accordingly, the power quality monitoring system of the present invention is significantly reduced in construction cost compared to the conventional power quality monitoring system.
도 1은 본 발명의 일 실시 예에 따른 전력 품질 모니터링 시스템을 나타내는 도면이다.1 is a view showing a power quality monitoring system according to an embodiment of the present invention.
도 2는 본 발명의 일 실시 예에 따른 전력 품질 측정 장치의 구성을 나타내는 도면이다.2 is a diagram illustrating a configuration of an apparatus for measuring power quality according to an embodiment of the present invention.
도 3은 본 발명의 일 실시 예에 따른 전압 파형 및 전류 파형에 상응하는 대표 파형을 예시한 도면이다.3 is a diagram illustrating a representative waveform corresponding to a voltage waveform and a current waveform according to an embodiment of the present invention.
도 4는 본 발명의 일 실시 예에 따른 서버를 나타내는 도면이다.4 is a diagram illustrating a server according to an exemplary embodiment.
도 5는 본 발명의 일 실시 예에 따른 전력 품질 측정 장치가 전력 품질을 측정하는 방법을 나타낸 순서도이다.5 is a flowchart illustrating a method of measuring power quality by an apparatus for measuring power quality according to an embodiment of the present invention.
본 발명은 다양한 변환을 가할 수 있고 여러 가지 실시예를 가질 수 있는 바, 특정 실시예들을 도면에 예시하고 상세한 설명에 상세하게 설명하고자 한다. 그러나, 이는 본 발명을 특정한 실시 형태에 대해 한정하려는 것이 아니며, 본 발명의 사상 및 기술 범위에 포함되는 모든 변환, 균등물 내지 대체물을 포함하는 것으로 이해되어야 한다. 본 발명을 설명함에 있어서 관련된 공지 기술에 대한 구체적인 설명이 본 발명의 요지를 흐릴 수 있다고 판단되는 경우 그 상세한 설명을 생략한다.As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.
제1, 제2 등의 용어는 다양한 구성요소들을 설명하는데 사용될 수 있지만, 상기 구성요소들은 상기 용어들에 의해 한정되어서는 안 된다. 상기 용어들은 하나의 구성요소를 다른 구성요소로부터 구별하는 목적으로만 사용된다. Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.
본 출원에서 사용한 용어는 단지 특정한 실시 예를 설명하기 위해 사용된 것으로, 본 발명을 한정하려는 의도가 아니다. 단수의 표현은 문맥상 명백하게 다르게 뜻하지 않는 한, 복수의 표현을 포함한다. 본 출원에서, "포함하다" 또는 "가지다" 등의 용어는 명세서상에 기재된 특징, 숫자, 단계, 동작, 구성요소, 부품 또는 이들을 조합한 것이 존재함을 지정하려는 것이지, 하나 또는 그 이상의 다른 특징들이나 숫자, 단계, 동작, 구성요소, 부품 또는 이들을 조합한 것들의 존재 또는 부가 가능성을 미리 배제하지 않는 것으로 이해되어야 한다.The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the 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.
이하, 본 발명의 실시 예를 첨부한 도면들을 참조하여 상세히 설명하기로 한다.Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
도 1은 본 발명의 일 실시 예에 따른 전력 품질 모니터링 시스템을 나타내는 도면이다.1 is a view showing a power quality monitoring system according to an embodiment of the present invention.
도 1을 참조하면, 본 발명의 일 실시 예에 따른 전력 품질 모니터링 시스템(10)은 전력 계통(20)에 연결되는 전력 품질 측정 장치(100) 및 전력 품질 측정 장치(100)에서 생성된 대표 파형을 수신하여 고속 푸리에 변환(Fast Fourier Transform, 이하 "FFT"라고 함) 연산을 수행하는 서버(200)를 포함한다.Referring to FIG. 1, the power quality monitoring system 10 according to an exemplary embodiment of the present invention may include a representative waveform generated by the power quality measuring apparatus 100 and the power quality measuring apparatus 100 connected to the power system 20. And a server 200 that receives the fast Fourier transform (FFT) operation.
전력 계통(20)은 3상 4선식으로 이루어진다. 전력 계통(20)은 변전소(30)의 주변압기(MTR) (40)에 연결되는 모선(50) 및 배전 선로(60)를 포함한다. 여기서, 모선(50)에는 계기용 변압기(Potential Transformer: PT)(70)가 상별로 설치된다. 또한, 배전 선로(60)에는 계기용 변류기(Current Transformet: CT)(80)가 상별로 설치된다.The power system 20 consists of a three-phase four-wire system. The power system 20 includes a bus bar 50 and a distribution line 60 connected to the peripheral pressure transformer (MTR) 40 of the substation 30. Here, the main transformer 50 is provided with a phase transformer (PT) 70 for each phase. In addition, a current transformer (CT) 80 is installed in each phase in the distribution line 60.
본 발명의 실시예에 따른, 전력 품질 측정 장치(100)는 변전소(30)의 주변압기(40)에 연결되는 모선(50) 뱅크 단위로 설치되거나, 전력 계통(20)의 모선(50)과 배전 선로(60) 각각의 인출점에 연결될 수 있으며, 이에 한정되지 않는다. According to an exemplary embodiment of the present invention, the power quality measuring apparatus 100 may be installed in units of banks of the bus bar 50 connected to the peripheral voltage transformer 40 of the substation 30, or may be connected to the bus bar 50 of the power system 20. The power distribution line 60 may be connected to the withdrawal points, but is not limited thereto.
전력 품질 측정 장치(100)는 모선(50)의 상별 전압 3채널 및 각 배전 선로(60)의 전류 4채널을 통해 설정된 시간 간격으로 전압 파형 및 전류 파형을 취득한다. 다음, 전력 품질 측정 장치(100)는 취득한 파형을 설정된 방법에 따라 샘플링하여 대표 파형 즉, 전압 대표 파형 및 전류 대표 파형을 생성한다. 또한, 전력 품질 측정 장치(100)는 생성한 전압 대표 파형 및 전류 대표 파형을 서버(200)로 전송한다.The power quality measuring apparatus 100 acquires a voltage waveform and a current waveform at time intervals set through three phase voltage channels of the bus line 50 and four current channels of each distribution line 60. Next, the power quality measuring apparatus 100 samples the acquired waveform according to a set method to generate a representative waveform, that is, a voltage representative waveform and a current representative waveform. In addition, the power quality measurement apparatus 100 transmits the generated voltage representative waveform and current representative waveform to the server 200.
서버(200)는 수신한 대표 파형을 미리 설정된 방법으로 변환하고, 변환된 결과를 분석하여 전력 계통(20)의 이상유무를 확인한다.The server 200 converts the received representative waveform into a preset method and analyzes the converted result to check whether there is an abnormality in the power system 20.
구체적으로, 서버(200)는 전력 품질 측정 장치(100)로부터 전압 대표 파형 및 전류 대표 파형을 수신하여 저장한다. 다음, 서버(200)는 전압 대표 파형 및 전류 대표 파형을 미리 설정된 방법 예를 들어, FFT 연산 에 따라 변환하여 전력 계통(20)의 전압 파형 및 전류 파형을 분석한다. 이때, 서버(200)는 고조파 차수별 파형의 분해 등을 수행하여 전력 계통(20)에 대해 다양한 해석 및 평가를 수행한다. 이를 통해 서버(200)는 전력 계통(20)의 이상 유무를 확인할 수 있다.In detail, the server 200 receives and stores a voltage representative waveform and a current representative waveform from the power quality measuring apparatus 100. Next, the server 200 analyzes the voltage waveform and the current waveform by converting the voltage representative waveform and the current representative waveform according to a predetermined method, for example, an FFT operation. At this time, the server 200 performs decomposition and the like of the waveform for each harmonic order to perform various analysis and evaluation on the power system 20. Through this, the server 200 may check whether there is an abnormality of the power system 20.
도 2는 본 발명의 일 실시 예에 따른 전력 품질 측정 장치의 구성을 나타내는 도면이다. 도 3은 본 발명의 일 실시 예에 따른 전압 파형 및 전류 파형에 상응하는 대표 파형을 예시한 도면이다.2 is a diagram illustrating a configuration of an apparatus for measuring power quality according to an embodiment of the present invention. 3 is a diagram illustrating a representative waveform corresponding to a voltage waveform and a current waveform according to an embodiment of the present invention.
도 2를 참조하면, 본 발명의 일 실시 예에 따른 전력 품질 측정 장치(100)는 픽업부(110), 샘플링부(120), 파형 생성부(130), 제1 저장부(140) 및 전송부(150)를 포함한다.Referring to FIG. 2, the power quality measuring apparatus 100 according to an embodiment of the present invention may include a pickup unit 110, a sampling unit 120, a waveform generator 130, a first storage unit 140, and a transmission unit. The unit 150 is included.
픽업부(110)는 전력 품질 측정 장치(100)가 연결된 전력 계통(20)의 전압 파형 및 전류 파형을 미리 설정된 시간 간격으로 취득한다. 예를 들면, 픽업부(110)는 1초, 3초, 10분 또는 30분 등으로 설정된 시간 간격에 맞춰 전력 계통의 전압 파형 및 전류 파형을 취득한다. 여기서, 전력 계통의 전압 파형 및 전류 파형을 취득하는 방법은 당업자에게 자명한 사항이므로 이에 대한 별도의 설명은 생략한다.The pickup unit 110 acquires the voltage waveform and the current waveform of the power system 20 to which the power quality measuring apparatus 100 is connected at predetermined time intervals. For example, the pickup unit 110 acquires the voltage waveform and the current waveform of the power system at a time interval set at 1 second, 3 seconds, 10 minutes or 30 minutes. Here, the method for acquiring the voltage waveform and the current waveform of the power system is obvious to those skilled in the art, and thus a separate description thereof will be omitted.
샘플링부(120)는 픽업부(110)에서 취득된 전압 파형 및 전류 파형을 미리 설정된 주기로 샘플링하여 디지털 파형으로 변환한다. 여기서, 샘플링부(120)는 (n은 7 이상의 자연수) 주기로 픽업부(110)를 통해 취득된 전압 파형 및 전류 파형을 샘플링할 수 있다. 이때, 샘플링부(120)에서 전압 파형 및 전류 파형을 샘플링하는 주기는 샘플링 주기라고 한다.The sampling unit 120 samples the voltage waveform and the current waveform acquired by the pickup unit 110 at a predetermined period and converts the waveform into a digital waveform. Here, the sampling unit 120 may sample the voltage waveform and the current waveform acquired through the pickup unit 110 at intervals (n is a natural number of 7 or more). In this case, the sampling period of the voltage waveform and the current waveform in the sampling unit 120 is called a sampling period.
IEC에서 규정하는 MV계통의 고조파 전압은 50차수까지 관리하는 것으로 정의되어 있으므로, 이에 대한 고조파 성분 분해를 위해서는 최소 128주기 또는 256 주기의 샘플링 주기가 필요하다. 만약 샘플링부(120)는 128 주기 미만의 샘플링 주기로 샘플링할 경우 50차수까지의 정확한 고조파 정보를 취득하기 어려울 수 있다. 이에 따라 본 명세서에서는 샘플링 주기가 128 주기 이상인 것으로 가정하여 설명한다.Since harmonic voltage of MV system regulated by IEC is defined to manage up to 50 orders, at least 128 cycles or 256 cycles are required for harmonic component resolution. If the sampling unit 120 samples with a sampling period of less than 128 cycles, it may be difficult to obtain accurate harmonic information up to 50 orders. Accordingly, in the present specification, it is assumed that the sampling cycle is 128 or more cycles.
샘플링부(120)는 지정된 샘플링 주기에 따라 샘플링된 전압 및 전류 파형을 제1 저장부(140)에 저장한다.The sampling unit 120 stores the voltage and current waveforms sampled according to the designated sampling period in the first storage unit 140.
파형 생성부(130)는 미리 설정된 측정 주기 동안 샘플링된 전압 파형 및 전류 파형을 하나의 사이클로 중첩시켜 합산하여 전압 대표 파형 및 전류 대표 파형을 생성한다. 여기서, 전압 대표 파형 또는 전류 대표 파형은 도 3에 도시된 바와 같이 생성될 수 있다. 예를 들어, 파형 생성부(130)는 도 3에 도시된 제1 샘플링 파형(310), 제2 샘플링 파형(320) 및 제3 샘플링 파형(330)과 같이 샘플링된 전압 파형 또는 전류 파형 각각을 하나의 사이클로 중첩시켜 동일 샘플링 주기의 값들을 합하여 전압 대표 파형 또는 전류 대표 파형을 생성한다.The waveform generator 130 generates a voltage representative waveform and a current representative waveform by overlapping and adding the sampled voltage waveform and the current waveform in one cycle during a preset measurement period. Here, the voltage representative waveform or the current representative waveform may be generated as shown in FIG. 3. For example, the waveform generator 130 may each of the sampled voltage waveforms or current waveforms, such as the first sampling waveform 310, the second sampling waveform 320, and the third sampling waveform 330 illustrated in FIG. 3. By superimposing in one cycle, the values of the same sampling period are summed to generate a voltage representative waveform or a current representative waveform.
본 발명의 일 실시 예에서는 이해와 설명의 편의를 도모하기 위해 측정 주기가 최대 수요 기간인 것으로 가정하여 설명한다. 예를 들어, 최대 수요 기간이 15분인 경우 측정 주기는 15분으로 설정될 수 있다. 또는 측정 주기가 3분, 10등과 같이 최대 수요 기간 이외의 다른 주기로 설정될 수도 있다.In an embodiment of the present invention, it is assumed that the measurement cycle is the maximum demand period in order to facilitate understanding and explanation. For example, if the maximum demand period is 15 minutes, the measurement period may be set to 15 minutes. Alternatively, the measurement period may be set to a period other than the maximum demand period, such as 3 minutes, 10, and so on.
예를 들어, 파형 생성부(130)는 측정 주기 동안 샘플링된 전압 및 전류 파형을 하나의 사이클로 중첩하여 합산하고, 이들의 평균값을 산출하여 전압 대표 파형 및 전류 대표 파형을 생성할 수 있다. 또한, 파형 생성부(130)는 측정 주기 동안 샘플링된 전압 및 전류 파형에 대해 샘플링 주기가 동일한 전압 및 전류 파형을 중첩/합산하여 전압 대표 파형 및 전류 대표 파형을 생성할 수 있다.For example, the waveform generator 130 may generate the voltage representative waveform and the current representative waveform by overlapping and summing the sampled voltage and current waveforms in one cycle during the measurement period, and calculating their average values. In addition, the waveform generator 130 may generate a voltage representative waveform and a current representative waveform by superimposing / summing voltage and current waveforms having the same sampling period with respect to the voltage and current waveforms sampled during the measurement period.
본 발명의 일 실시 예의 경우, 도 3에서 예시된 바와 같이, 전력 품질 측정 장치(100) 각각의 샘플링된 전압 및 전류 파형에 대해 각각의 사이클을 하나의 사이클로 중첩시켜 전압 대표 파형 및 전류 대표 파형을 생성함으로써, 샘플링된 데이터 양을 감소시킬 수 있다.In an exemplary embodiment of the present invention, as illustrated in FIG. 3, the cycles of the voltage representative waveform and the current representative waveform are superimposed by overlapping each cycle into one cycle for the sampled voltage and current waveforms of the power quality measurement apparatus 100. By generating, the amount of sampled data can be reduced.
일반적으로 전력 계통(20)에서 전압 파형 및 전류 파형은 사고, 고장 등으로 인한 정전, 순간전압강하, 낙뢰, 개폐기의 투개방에 따른 서지 등과 같은 내외적인 이벤트 발생이 아니면 급격하게 변하지 않는다.In general, the voltage waveform and the current waveform in the power system 20 do not change drastically unless an internal or external event occurs such as a power failure due to an accident, a failure, a voltage drop, a lightning strike, or a surge due to the opening and closing of a switch.
이에 착안하여 본 발명의 일 실시 예에서는 전력 품질 측정 장치(100)에서 측정 주기 동안 샘플링된 전압 및 전류 파형에 대한 전압 대표 파형 및 전류 대표 파형을 생성하여 원격지의 서버(200)로 전송하도록 할 수 있다.With this in mind, in one embodiment of the present invention, the power quality measuring apparatus 100 may generate a voltage representative waveform and a current representative waveform for the voltage and current waveforms sampled during the measurement period, and transmit the generated voltage representative waveform and the current representative waveform to the remote server 200. have.
이에 따라, 서버(200)에서는 전력 품질 측정 장치(100)에서 수신된 전압 대표 파형 및 전류 대표 파형의 반주기에 상응하는 샘플 데이터를 산출하여 고조파를 평가할 수 있다.Accordingly, the server 200 may calculate harmonics by calculating sample data corresponding to half periods of the voltage representative waveform and the current representative waveform received from the power quality measuring apparatus 100.
제1 저장부(140)는 샘플링부(120)를 통해 샘플링된 전압 및 전류 파형이 측정 주기 동안 축적되어 저장된다. 또한, 제1 저장부(140)는 본 발명의 일 실시 예에 따른 전력 품질 측정 장치(100)를 운용하기 위해 필요한 알고리즘이 저장된다.The first storage unit 140 accumulates and stores voltage and current waveforms sampled through the sampling unit 120 during a measurement period. In addition, the first storage unit 140 stores an algorithm required to operate the power quality measuring apparatus 100 according to an embodiment of the present invention.
전송부(150)는 파형 생성부(130)를 통해 생성된 전압 대표 파형 및 전류 대표 파형을 원격지의 서버(200)로 전송하는 기능을 수행한다.The transmitter 150 transmits the voltage representative waveform and the current representative waveform generated by the waveform generator 130 to the remote server 200.
도 4는 본 발명의 일 실시 예에 따른 서버를 나타내는 도면이다.4 is a diagram illustrating a server according to an exemplary embodiment.
도 4를 참조하면, 본 발명의 일 실시 예에 따른 서버(200)는 수신부(210), 제2 저장부(220)와 연산부(230)를 포함한다.Referring to FIG. 4, the server 200 according to an embodiment of the present invention includes a receiver 210, a second storage unit 220, and a calculator 230.
수신부(210)는 전력 품질 측정 장치(100)로부터 전압 대표 파형 및 전류 대표 파형을 수신한다.The receiver 210 receives a voltage representative waveform and a current representative waveform from the power quality measuring apparatus 100.
제2 저장부(220)는 전력 품질 측정 장치(100)로부터 전달받은 전압 대표 파형 및 전류 대표 파형을 저장한다. 여기서 제2 저장부(220)는 전압 대표 파형 및 전류 대표 파형을 저장하는 데이터 베이스 형태로 형성될 수 있다.The second storage unit 220 stores the voltage representative waveform and the current representative waveform received from the power quality measuring apparatus 100. The second storage unit 220 may be formed in the form of a database that stores the voltage representative waveform and the current representative waveform.
연산부(230)는 미리 설정된 방법에 따라 전압 대표 파형 및 전류 대표 파형을 FFT 연산하여 전력 계통(20)의 전압 파형 및 전류 파형을 분석한다. 연산부(230)는 고조파 차수별 파형의 분해 등을 수행하여 고조파 평가값을 산출한다. 연산부(230)는 산출된 평가값을 이용하여 전력 계통(20)에 대해 다양한 해석 및 평가를 수행한다. 이를 통해 서버(200)는 전력 계통(20)의 이상 유무를 확인할 수 있다.The calculation unit 230 analyzes the voltage waveform and the current waveform of the power system 20 by FFTing the voltage representative waveform and the current representative waveform according to a preset method. The calculation unit 230 calculates harmonic evaluation values by performing decomposition of waveforms according to harmonic orders. The calculation unit 230 performs various analysis and evaluation on the power system 20 using the calculated evaluation value. Through this, the server 200 may check whether there is an abnormality of the power system 20.
여기서, 연산부(230)는 사용자의 지시를 입력받은 경우에만 FFT 변환을 실시하고, 전압 파형 및 전류 파형을 분석할 수 있다.Here, the calculation unit 230 may perform the FFT conversion only when the user's instruction is input, and analyze the voltage waveform and the current waveform.
종래의 전력 품질 모니터링 시스템과 비교하여 본 발명의 일 실시 예에 따른 전력 품질 모니터링 시스템은 대표값의 산출 주기가 감소한다. 여기서 대표값은 IEC에서 규정하는 12 싸이클(cycle) 단위로 FFT 연산을 수행하여 사용자가 지정하는 기간에 해당되는 RMS(Root mean square) 산출값을 의미한다. 종래의 전력 품질 모니터링 시스템은 대표값을 산출하기 위해 12 싸이클 단위로 FFT를 연산하였으나, 본 발명의 일 실시 예에 따른 전력 품질 모니터링 시스템에서는 12 싸이클 단위의 샘플링된 파형을 연속적으로 중첩시킨 후 사용자가 지정하는 기간 동안 1 싸이클 마다 128 또는 256 샘플링 비율 이상으로 샘플링 및 파형 중첩을 수행하고, 전력 공급자의 정책에 따른 대표값 주기에 의해 대표 파형을 산출한다. 이에 따라 본 발명의 일 실시 예에 따른 전력 품질 모니터링 시스템은 종래에 비해 정밀도 및 신뢰도가 향상된다. Compared with the conventional power quality monitoring system, the power quality monitoring system according to an embodiment of the present invention reduces the calculation period of the representative value. Here, the representative value means a root mean square (RMS) calculated value corresponding to a period designated by a user by performing an FFT operation in units of 12 cycles prescribed by IEC. In the conventional power quality monitoring system, the FFT is calculated in units of 12 cycles in order to calculate a representative value. However, in the power quality monitoring system according to an exemplary embodiment of the present invention, the user continuously after overlapping the sampled waveforms in units of 12 cycles. Sampling and waveform superimposition are performed at a 128 or 256 sampling rate or more per cycle for a specified period, and a representative waveform is calculated by a representative value period according to the power provider's policy. Accordingly, the power quality monitoring system according to an embodiment of the present invention has improved accuracy and reliability compared to the prior art.
또한, 본 발명의 일 실시 예에 따른 전력 품질 모니터링 시스템은 대표 파형의 산출 및 대표 파형의 FFT 연산이 전력 품질 측정 장치와 서버에서 나누어 수행된다. 전력 품질 측정 장치는 서버로 대표 파형만 전송하면 되므로 연산에 따른 부하와 네트워크 부하를 줄일 수 있다. 그리고 서버는 사용자가 원하는 시간대에 FFT 연산을 수행할 수 있다. 이에 따라 본 발명의 일 실시 예에 따른 전력 품질 모니터링 시스템은 확장성이 용이하고 측정 정차가 간소해진다.In addition, in the power quality monitoring system according to an embodiment of the present invention, the representative waveform and the FFT calculation of the representative waveform are divided in the power quality measuring apparatus and the server. The power quality measurement device only needs to transmit a representative waveform to the server, thereby reducing the computational load and the network load. The server may perform an FFT operation at a time desired by the user. Accordingly, the power quality monitoring system according to an embodiment of the present invention is easily scalable and the measurement stop is simplified.
또한, 본 발명의 일 실시 예에 따른 전력 품질 모니터링 시스템은 모선 및 배전 선로의 인출 선로별 측정 항목을 별도로 분리하여 변전소의 주변압기별로 전압 파형과 전류 파형을 측정하므로 전력 품질의 종합적인 관리가 가능하고, 파형 측정을 위한 채널수가 감소된다. 이에 따라 본원 발명의 전력 품질 모니터링 시스템은 구축 비용이 종래의 전력 품질 모니터링 시스템과 비교하여 대폭 감소한다.In addition, the power quality monitoring system according to an embodiment of the present invention separates the measurement items for each outgoing line of the bus and distribution lines to measure voltage waveforms and current waveforms for each of the periphery transformers of the substation, thereby enabling comprehensive management of power quality. The number of channels for waveform measurement is reduced. Accordingly, the power quality monitoring system of the present invention is significantly reduced in construction cost compared to the conventional power quality monitoring system.
도 5는 본 발명의 일 실시 예에 따른 전력 품질 측정 장치가 전력 품질을 측정하는 방법을 나타낸 순서도이다.5 is a flowchart illustrating a method of measuring power quality by an apparatus for measuring power quality according to an embodiment of the present invention.
이하에서 수행되는 각각의 단계는 전력 품질 모니터링 시스템(10)에 포함된 전력 품질 측정 장치(100) 및 서버(200)의 내부 구성 요소에 의해 수행되어지나 이해와 설명의 편의를 도모하기 위해 전력 품질 측정 장치(100)와 서버(200)로 통칭하여 설명하기로 한다.Each step performed below is performed by the power quality measuring apparatus 100 and the internal components of the server 200 included in the power quality monitoring system 10, but the power quality is for convenience of understanding and explanation. The measurement apparatus 100 and the server 200 will be collectively described.
전력 품질 측정 장치(100)는 전력 계통의 모선(50) 및 의 상별 전압 3채널 및 각 배전 선로(60)의 전류 4채널을 통해 설정된 시간 간격으로 전압 파형 및 전류 파형을 취득한다(S10).The power quality measuring apparatus 100 acquires a voltage waveform and a current waveform at time intervals set through three channels of phase voltages of the power line 50 and the power grid and four channels of current of each power distribution line 60 (S10).
구체적으로,전력 품질 측정 장치(100)는 전력 계통의 모선 및 배전 선로에 연결되어 모선의 상별 3채널 전압 파형과 각 배전 선로의 4채널 전류 파형을 설정된 시간마다 취득한다. 전력 품질 측정 장치(100)는 모선에 설치된 계기용 변압기로부터 상별 3채널 전압을 수신하여 전압 파형을 취득한다. 또한, 전력 품질 측정 장치(100)는 각 배전 선로에 설치된 계기용 변류기로부터 4채널 전류를 수신하여 전류 파형을 취득한다.Specifically, the power quality measuring apparatus 100 is connected to the bus and distribution lines of the power system to acquire phase 3-channel voltage waveforms of the bus and 4-channel current waveforms of each distribution line at predetermined times. The power quality measuring apparatus 100 receives a three-channel voltage for each phase from an instrument transformer installed in a bus, and acquires a voltage waveform. In addition, the power quality measuring apparatus 100 receives a four-channel current from the current transformer for the instrument installed in each distribution line to obtain a current waveform.
전력 품질 측정 장치(100)는 취득된 전압 및 전류 파형을 정해진 샘플링 주기로 샘플링하고, 이를 저장한다(S20). 이는 전술한 바와 동일하므로 이에 대한 중첩되는 설명은 생략하기로 한다.The power quality measuring apparatus 100 samples the acquired voltage and current waveforms at a predetermined sampling period and stores them (S20). Since this is the same as described above, overlapping description thereof will be omitted.
전력 품질 측정 장치(100)는 측정 주기 동안 샘플링된 전압 및 전류 파형을 하나의 사이클로 중첩하여 전압 대표 파형 및 전류 대표 파형을 생성한다(S30). 예를 들어, 전력 품질 측정 장치(100)는 샘플링된 전압 및 전류 파형을 하나의 사이클로 중첩하고 이에 대한 평균값을 산출하여 이를 이용하여 전압 대표 파형 및 전류 대표 파형을 생성할 수 있다. The power quality measuring apparatus 100 generates a voltage representative waveform and a current representative waveform by superimposing the sampled voltage and current waveforms in one cycle during the measurement period (S30). For example, the power quality measuring apparatus 100 may overlap the sampled voltage and current waveforms in one cycle, calculate an average value thereof, and generate a voltage representative waveform and a current representative waveform using the averaged values.
다음, 전력 품질 측정 장치(100)는 생성된 전압 대표 파형 및 전류 대표 파형을 서버(200)로 전송한다(S40).Next, the power quality measuring apparatus 100 transmits the generated voltage representative waveform and current representative waveform to the server 200 (S40).
서버(200)는 전송받은 전압 대표 파형 및 전류 대표 파형을 FFT 연산한다. 이를 통해 서버는 전압 대표 파형 및 전류 대표 파형을 분석한다(S50). 서버(200)는 고조파 차수별 파형의 분해 등을 수행하여 고조파 평가값을 산출한다. 서버(200)는 산출된 평가값을 이용하여 전력 계통에 대해 다양한 해석 및 평가를 수행한다. 이를 통해 서버는 전력 계통의 이상 유무를 확인한다.The server 200 performs an FFT operation on the received voltage representative waveform and current representative waveform. Through this, the server analyzes the voltage representative waveform and the current representative waveform (S50). The server 200 calculates harmonic evaluation values by performing decomposition of waveforms according to harmonic orders. The server 200 performs various analysis and evaluation on the power system using the calculated evaluation value. Through this, the server checks whether the power system is abnormal.
상기에서는 본 발명의 바람직한 실시예를 참조하여 설명하였지만, 해당 기술 분야에서 통상의 지식을 가진 자라면 하기의 특허 청구의 범위에 기재된 본 발명의 사상 및 영역으로부터 벗어나지 않는 범위 내에서 본 발명을 다양하게 수정 및 변경시킬 수 있음을 이해할 수 있을 것이다.Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art to which the present invention pertains without departing from the spirit and scope of the present invention as set forth in the claims below It will be appreciated that modifications and variations can be made.

Claims (10)

  1. 전력 계통의 전력 품질을 모니터링하는 장치에 있어서,A device for monitoring the power quality of a power system,
    전력 계통의 모선 및 배전 선로에 연결되어 설정된 시간 간격으로 상기 모선 및 상기 배전 선로 각각에서 전압 파형을 취득하고, 취득한 전압 파형 및 전류 파형을 설정된 주기로 샘플링하여, 설정된 측정 주기 동안 샘플링된 전압 파형 및 전류 파형을 하나의 사이클로 중첩시켜 전압 대표 파형 및 전류 대표 파형을 생성하여 전송하는 전력 품질 측정 장치; 및Voltage waveforms and currents sampled during a set measurement period by acquiring voltage waveforms from each of the bus lines and the distribution lines at set time intervals connected to the bus and distribution lines of the power system, and sampling the acquired voltage and current waveforms at set periods. A power quality measuring device for generating and transmitting a voltage representative waveform and a current representative waveform by superimposing the waveforms in one cycle; And
    상기 전압 대표 파형 및 상기 전류 대표 파형을 각각 고속 푸리에 변환을 통해 고조파 성분으로 분해하고, 상기 고조파 성분을 분석하여 상기 전력 계통의 이상 발생을 감시하는 서버를 포함하는 전력 품질 모니터링 시스템.And a server which decomposes the voltage representative waveform and the current representative waveform into harmonic components through a fast Fourier transform, respectively, and analyzes the harmonic components to monitor occurrence of abnormalities in the power system.
  2. 제1 항에 있어서,According to claim 1,
    상기 전력 품질 측정 장치는The power quality measuring device
    상기 설정된 시간 간격으로 상기 전력 계통으로부터 전압 파형 및 전류 파형을 취득하는 픽업부;A pickup unit which acquires a voltage waveform and a current waveform from the power system at the set time intervals;
    고조파 성분 분해를 위해 상기 취득된 전압 및 전류 파형을 상기 설정된 샘플링 주기로 샘플링하여 저장하는 샘플링부;A sampling unit for sampling and storing the acquired voltage and current waveforms in the set sampling period for harmonic component decomposition;
    상기 설정된 측정 주기 동안 상기 샘플링된 전압 파형 및 전류 파형 각각을 하나의 사이클로 중첩하여 상기 전압 대표 파형 및 상기 전류 대표 파형을 생성하는 파형 생성부; 및A waveform generator for generating the voltage representative waveform and the current representative waveform by overlapping each of the sampled voltage waveform and current waveform in one cycle during the set measurement period; And
    상기 전압 대표 파형 및 상기 전류 대표 파형을 통신망을 통해 상기 서버로 전송하는 전송부를 포함하는 전력 품질 모니터링 시스템.And a transmitter configured to transmit the voltage representative waveform and the current representative waveform to the server through a communication network.
  3. 제2 항에 있어서,The method of claim 2,
    상기 픽업부는The pickup portion
    상기 모선에 설치된 계기용 변압기로부터 3채널의 전압 파형을 취득하고, 각 배전 선로에 설치된 계기용 변류기로부터 4채널의 전류 파형을 취득하는 것을 특징으로 하는 전력 품질 모니터링 시스템.And a three-channel voltage waveform from an instrument transformer provided in the bus line, and a four-channel current waveform from an instrument current transformer provided in each distribution line.
  4. 제2 항에 있어서,The method of claim 2,
    상기 파형 생성부는 하나의 사이클로 중첩된 상기 전압 파형들 및 상기 전류 파형들 각각의 평균값으로 상기 전압 대표 파형 및 상기 전류 대표 파형을 생성하는 것을 특징으로 하는 전력 품질 모니터링 시스템.And the waveform generator generates the voltage representative waveform and the current representative waveform as average values of each of the voltage waveforms and the current waveforms superimposed in one cycle.
  5. 제4 항에 있어서,The method of claim 4, wherein
    상기 전압 대표 파형 및 상기 전류 대표 파형 각각은 중첩된 전압 파형 및 전류 파형의 전체 주기의 반주기 값인 것을 특징으로 하는 전력 품질 모니터링 시스템.And wherein each of the voltage representative waveform and the current representative waveform is a half-period value of the entire period of the superimposed voltage waveform and the current waveform.
  6. 제2 항에 있어서,The method of claim 2,
    상기 샘플링부는 128 주기 이상으로 상기 취득된 전압 파형 및 전류 파형 각각을 샘플링하는 것을 특징으로 하는 전력 품질 모니터링 시스템.And the sampling unit samples each of the acquired voltage waveform and current waveform in at least 128 cycles.
  7. 제1 항에 있어서,According to claim 1,
    상기 서버는 상기 전압 대표 파형 및 상기 전류 대표 파형을 저장하는 저장부를 더 포함하는 것을 특징으로 하는 전력 품질 모니터링 시스템.The server further comprises a storage unit for storing the voltage representative waveform and the current representative waveform.
  8. 전력 계통의 전력 품질을 모니터링하는 방법에 있어서,In the method of monitoring the power quality of the power system,
    (a) 전력 계통의 모선 및 배전 선로 각각으로부터 설정된 시간 간격으로 전압 파형 및 전류 파형을 취득하는 단계;(a) acquiring a voltage waveform and a current waveform at predetermined time intervals from each of the bus and distribution lines of the power system;
    (b) 취득한 전압 파형 및 전류 파형 각각을 설정된 주기로 샘플링하는 단계;(b) sampling each of the acquired voltage waveforms and current waveforms at a set period;
    (c) 설정된 측정 주기 동안 샘플링된 상기 전압 파형 및 상기 전류 파형 각각을 하나의 사이클로 중첩하여 전압 대표 파형 및 전류 대표 파형을 생성하는 단계; 및(c) generating a voltage representative waveform and a current representative waveform by superimposing each of the voltage waveform and the current waveform sampled during a set measurement period in one cycle; And
    (d) 상기 전압 대표 파형 및 상기 전류 대표 파형을 FFT 변환하여 분석하는 단계를 포함하는 전력 품질 모니터링 방법.(d) FFT converting and analyzing the voltage representative waveform and the current representative waveform.
  9. 제8 항에 있어서,The method of claim 8,
    상기 (a) 단계는Step (a) is
    상기 모선에서 상별 전압 3채널을 통해 상기 전압 파형을 취득하고,Acquire the voltage waveform through three phase voltage channels in the bus bar,
    상기 배전 선로에서 전류 4채널을 통해 상기 전류 파형을 취득하는 것을 특징으로 하는 전력 품질 모니터링 방법.And acquiring the current waveform through four channels of current in the distribution line.
  10. 제8 항에 있어서,The method of claim 8,
    상기 (c) 단계는Step (c) is
    상기 측정 주기 동안 샘플링된 상기 전압 파형 및 상기 전류 파형 중 동일한 주기의 전압 파형 및 전류 파형을 중첩하는 것을 특징으로 하는 전력 품질 모니터링 방법.And a voltage waveform and a current waveform of the same period among the voltage waveform and the current waveform sampled during the measurement period are superimposed.
PCT/KR2010/006380 2010-06-30 2010-09-17 Power quality monitoring system and method thereof WO2012002615A1 (en)

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