KR101918189B1 - Device and method for measuring electric power - Google Patents

Abstract

The present invention relates to a device for measuring electric power and, more specifically, to a device for measuring electric power and a method thereof capable of measuring active and reactive power actually used in a branch line, synchronizing a phase of an incoming voltage or current signal, and measuring accurate electric power even in the presence of distortion. By the device for measuring electric power and a device thereof according to an embodiment of the present invention, by using a zero-crossing detection signal of an incoming signal, accurate measurement on active and reactive power is possible by solving the phase difference problem when transmitting a measurement voltage, an analog signal value of a current, or a digital signal value, and the device has strong resistance against external noise by using a virtual voltage when instantaneous deformation or distortion of a voltage waveform occurs.

Description

TECHNICAL FIELD [0001] The present invention relates to a power measuring apparatus,

The present invention relates to a power measuring apparatus, and more particularly, to a power measuring apparatus that measures active power and reactive power actually used in a branch line, synchronizes a phase of an incoming voltage or current signal, And more particularly, to a power measurement apparatus and method.

An electric distribution board or a distribution board is a device used to distribute electric power supplied from outside in indoor wiring such as a building and supply it to each element in the house and to open and close the electric power supply. In this case, in the case of the distribution board or distribution board, the main line is branched to a plurality of branch lines through a molded case circuit breaker (MCCB), and power is supplied to the load of each branch line again through the sub- In this case, a measuring device for measuring the used electric power is required for the main line and the branch line, respectively. Conventionally, both the voltage and the current are detected for each measuring device and the active power is calculated by multiplying the voltage and the current.

As a preliminary step for such power measurement, it is necessary to detect voltage and current. Generally, voltage and current are measured using a potential transformer (PT) and a current transformer (CT). The method using a current transformer uses electromagnetic induction phenomenon, and it is easy to ensure relatively high accuracy. However, when the current is large, the current transformer is saturated. In the case of a large current, the weight is heavy.

In order to solve these problems, a technique of installing only a current transformer in each branch line, constructing all equipment for power measurement of the branch line at the main line, and receiving the current information measured from the branch line and measuring the power. However, in such a case, the measuring equipment provided in the main line requires an analog digital converter (ADC) with excellent performance and a processor with excellent calculation performance, which increases the technical difficulty and increases the cost.

To improve this, Patent Document 10-1012271 (multi-line power measurement system for increasing efficiency and simplicity) and Registered Patent Publication No. 10-1469448 (multi-line power measurement system for increasing efficiency and simplicity) A technique of receiving a voltage value measured by a voltage meter provided on a main line by RS-485 communication and calculating the amount of power by using the current measured by each current meter provided on a branch line, and synchronizing the generation time of the voltage value and the current value Lt; / RTI > However, since the prior art fails to perform real-time measurement by bidirectional communication, errors and phase differences occur in the process of measuring the amount of electric power due to the difference between the detection time of the voltage and current and the time of measuring the amount of electric power (i.e., Only the effective power is calculated without reflecting the phase. In addition, Japanese Patent Application Laid-Open No. 10-1687537 (multi-line power meter and method thereof) has a current measuring module on a branch line, receives an analog voltage value from a power measuring gateway located on a main line, measures a voltage phase, Thereby calculating a power amount. However, even in such a conventional technique, a time delay may occur in measuring the voltage phase by receiving the voltage value of the main line periodically, and there is no method for measuring the accurate voltage phase. There is a problem that the accuracy of the power measurement is deteriorated when distortion occurs in a certain section in the course of transmission.

Patent Registration No. 10-1012271 (Feb. Patent Registration No. 10-1469448 (Aug. 2014) Patent Registration No. 10-1687537 (2017.01.20)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a power measuring apparatus and method capable of measuring an efficient and accurate amount of power by using a virtual voltage synchronized with a main line voltage.

In order to achieve the above object, a power measuring apparatus of the present invention comprises: a main line meter for generating a ground level detection signal from a voltage signal installed on a main line and leading to a main line; And a branch line meter for calculating the power of the branch line by using the virtual voltage generated by using the detected ground potential detection signal and the current measured from the branch line.

The zero-current detection signal may be a spherical file having the same frequency and phase as the voltage signal input to the main line.

The main line measuring apparatus includes a voltage measuring unit for measuring the voltage of the main line, a current measuring unit for measuring the current of the main line, and a power calculating unit for calculating the power of the main line by using the measurement results of the voltage measuring unit and the current measuring unit. And a calculation unit.

The current measuring unit may be a current transformer or a Rogowski coil.

The power calculator may calculate the active power, the reactive power, or the apparent power by reflecting the phase difference between the voltage and the current drawn into the main line from the electromotive force detection signal.

The coarse measuring instrument may further include a display unit for displaying the calculated power value.

And the coarse measuring instrument may include a transmitter for transmitting the geomagnetic detection signal to the ground wire measuring instrument.

The transmitter may be a wired communication module of one of RS-485, RS-232, and RS-422 communication methods.

The transmitter may be a wireless communication module such as Bluetooth, Near Field Communication (NFC), ZigBee, Magnetic Secure Transmission (MST), Beacon, Ethernet or WiFi have.

The coarse measuring instrument may further include a virtual voltage generator for generating a virtual voltage having the same peak value as the voltage drawn to the main line from the zero potential detection signal.

The power calculation unit may calculate the active power, the reactive power, or the apparent power by reflecting the phase difference between the voltage and the current drawn into the main line from the virtual voltage.

The branch line measuring device includes a current transformer for measuring the current of the branch line, a virtual voltage generator for generating a virtual voltage from the zero-current detection signal, and a controller for calculating a branch line power using the measured result of the current transformer and the virtual voltage And a power calculation unit.

The virtual voltage may be a signal obtained by amplifying the Zero Cross signal so that the virtual voltage has the same peak value as the peak value of the voltage input to the main line.

The virtual voltage may have one of a square wave, a sinusoidal wave, a triangular wave, and a rectified wave.

The power calculation unit of the branch line measuring instrument may calculate the active power, the reactive power, or the apparent power by reflecting the phase difference between the voltage and the current drawn into the main line from the virtual voltage.

The coarse power measuring apparatus of the present invention may further include a transformer for measuring the voltage of the coarse line, a current transformer for measuring the coarse current, a coarse detection unit for generating a coarse detection signal from the coarse voltage signal, A power calculation unit for calculating the power of the main line using the measurement results of the transformer and the current transformer and a communication unit for transmitting the geomagnetism detection signal generated in the geomagnetism detection unit to a branch line measuring instrument installed on the branch line.

The branch line power measuring apparatus of the present invention further comprises a current transformer for measuring the current of the branch line, a communication section for receiving the over-current detection signal from the main line meter provided on the main line, And a power calculation unit calculating the power of the branch line using the measurement result of the current transformer and the virtual voltage.

The power measuring apparatus of the present invention further includes a branch wire measuring instrument provided on the branch wire to generate an over-current detecting signal from a voltage signal inputted to the branch wire, And a main line meter for calculating the power of the main line by using the virtual voltage generated by the main line and the current measured by the main line.

The branch line power measuring apparatus of the present invention may further include a transformer for measuring the voltage of the branch line, a current transformer for measuring the current of the branch line, a geomagnetism detection unit for generating a geomagnetism detection signal from the voltage signal of the branch line, A power calculation unit for calculating the power of the branch line using the measurement results of the transformer and the current transformer; and a communication unit for transmitting the geomagnetism detection signal generated by the geomagnetism detection unit to a coarse measuring instrument installed on the coarse line.

The main line power measuring apparatus of the present invention further comprises a current transformer for measuring the current of the main line, a communication unit for receiving the ground potential detection signal from the branch line meter installed on the branch line, A voltage generating unit, and a power calculating unit for calculating the power of the main line using the measured result of the current transformer and the virtual voltage.

According to another aspect of the present invention, there is provided a power measuring method comprising the steps of: generating an over-current detection signal from a voltage signal input to a main line in a main line installed on a main line; The method comprising the steps of: receiving a geomagnetism detection signal transmitted from the coarse measuring instrument at a ground wire measuring instrument installed on the branch line; generating a virtual voltage using the geomagnetism detection signal; And calculating the power of the branch line using the generated current.

According to another aspect of the present invention, there is provided a coarse power measuring method comprising the steps of measuring a voltage of a coarse line, measuring a current of the coarse line, generating a coarse detection signal from the coarse voltage signal, Calculating a power of the main line using the overcurrent, and transmitting the electromotive force detection signal to a branch wire measuring instrument installed on the branch line.

According to another aspect of the present invention, there is provided a branch line power measuring method comprising the steps of: measuring current of a branch line; receiving a zero-potential detection signal from a main line meter installed on a main line; generating a virtual voltage from the zero- , And calculating the power of the branch line using the measured current and the virtual voltage.

According to another aspect of the present invention, there is provided a power measuring method comprising the steps of: generating a ground potential detection signal from a voltage signal input to a branch line in a branch line instrument installed on a branch line; and transmitting the ground potential detection signal to a main line instrument installed in the main line The method comprising the steps of: receiving a ground potential detection signal transmitted from the ground wire measuring instrument at a coaxial measuring instrument provided on the coaxial line; generating a virtual voltage using the coaxial detection signal; And calculating the power of the main line using the measured current.

The branch line power measuring method of the present invention further includes the steps of measuring the voltage of the branch line, measuring the current of the branch line, generating a zero-potential detection signal from the branch line voltage signal, Calculating a power of a branch line using an overcurrent, and transmitting the zero-current detection signal to a main line measuring instrument provided on a main line.

According to another aspect of the present invention, there is provided a coarse power measuring method comprising the steps of: measuring a current of a coarse line; receiving a coarse detection signal from a ground line measuring device installed on a coarse line; generating a virtual voltage from the coarse detection signal; , And calculating the power of the main line using the measured current and the virtual voltage.

According to the power measuring apparatus and method according to the embodiment of the present invention, by using the zero-crossing detection signal of the incoming signal, the voltage and / It is possible to accurately measure the active power and the reactive power, and even if the voltage waveform is instantaneously deformed or distorted, the virtual voltage is used so that the resistance against external noise is strong.

1 is an overall block diagram of a power measuring apparatus according to an embodiment of the present invention;
FIG. 2 is a detailed block diagram of a line measuring instrument and a ground line measuring instrument in the power measuring apparatus according to the embodiment of the present invention,
FIG. 3 is a signal waveform diagram of a process of generating a zero-potential detection signal and a virtual voltage in the power measuring apparatus according to the embodiment of the present invention,
FIG. 4 is a detailed block diagram of a power measuring apparatus according to another embodiment of the present invention, in which a virtual voltage generating unit is provided on both the coarse measuring instrument and the ground measuring instrument.
5 is a detailed block diagram of a power measuring apparatus according to another embodiment of the present invention in a case where a virtual voltage generating unit is provided in a coaxial measuring instrument 100,
6 is a block diagram showing a case in which a ground voltage measuring unit 200 includes a virtual voltage generating unit in both the coarse measuring instrument and the ground measuring instrument in the power measuring apparatus according to another embodiment of the present invention, ,
7 is a flowchart of a power measurement method according to an embodiment of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. Means that a particular feature, region, integer, step, operation, element and / or component is specified, and that other specific features, regions, integers, steps, operations, elements, components, and / And the like.

Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Commonly used predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

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

1 is an overall block diagram of a power measuring apparatus according to an embodiment of the present invention. Referring to FIG. 1, the power measuring apparatus 300 of the present invention may include a main line meter 100 installed on a main line and a branch line meter 200 installed on a branch line. The main measuring instrument 100 may be connected to a main wiring breaker 10 for cutting off an overcurrent generated in the event of a short circuit or an overload. The ground wire measuring instrument 200 may include a sub- As shown in FIG. The power measuring apparatus 300 of the present invention detects the zero crossing of a signal input from the coarse measuring instrument 100 and transmits the detected signal Zx to the branch measuring instrument 200. The zero potential detection signal Zx will be a signal having the same phase and the same amplitude as the phase of the incoming signal. The signal for detecting the electric potential may be a pull-in voltage or a pull-in current.

)에 의해 무효 전력이 발생하고 유효 전력은 인입 전압(V) * 인입 전류(I) * cos

가 된다. 본 발명의 전력 계측 장치(300)에서는 인입 신호의 영전위를 검출하여 인입 전압 또는 인입 전류의 위상을 알 수 있고, 이를 이용하여 인입 전압과 인입 전류의 위상차(

)를 확인할 수 있기 때문에, 전력 기기에 의해서 실제 사용되는 유효 전력을 계산하는 것도 가능하다.Power can be divided into active power, which is used to work in a load, and reactive power, which does not consume energy. If the phases of the input voltage and the input current are the same, the reactive power becomes 0 and the power consumption becomes the input voltage (V) * the input current (I). However, when the input voltage and the input current have different phases, Phase difference

) And reactive power is generated by the incoming voltage (V) * incoming current (I) * cos

. In the power measuring apparatus 300 of the present invention, it is possible to know the phase of the incoming voltage or the incoming current by detecting the electric potential of the incoming signal. By using the phase difference of the incoming voltage and the incoming current

, It is also possible to calculate the actual power actually used by the power device.

The branch line measuring instrument 200 generates a virtual voltage having the same phase as the lead-in voltage using the over-current detection signal Zx received from the coarse measuring instrument 100 and measures the power of the branch line using the generated virtual voltage. When detecting a superposition voltage from an input voltage, a virtual voltage is generated using the superposition voltage, and when a superposition voltage is detected from an input current, a virtual current may be generated using the superposition voltage.

The power measurement apparatus 300 of the present invention can measure the ground voltage of the ground wire measuring instrument 200 using the ground potential of the input voltage without passing the voltage value measured from the grounding measuring instrument 100 to the ground wire measuring instrument 200, Since the virtual voltage of the same phase is directly generated from the coarse measuring instrument 100, there is no delay in transferring the voltage value of the lead voltage from the coarse measuring instrument 100. In addition, since the virtual voltage is directly generated in the branch wire measuring instrument 200 without transmitting the input voltage value measured by the coaxial measuring instrument 100 to the branch wire measuring instrument 200, even when distortion of the inlet voltage occurs in the main line, The value is not transmitted to the branch line measuring instrument 200. As a result, even if there is distortion of the incoming voltage in the main line, the line measuring device 200 can calculate the power according to the virtual voltage generated by itself, and accurate power measurement is possible regardless of the distortion of the incoming voltage.

The power measuring apparatus 300 of the present invention may be constituted by a single product in which the coarse measuring instrument 100 and the ground measuring instrument 200 are combined and may be constituted by a coarse measuring instrument 100 including an electrostatic potential detecting function, The branch line measuring device 200 that generates a virtual voltage using a signal may be configured as an individual product.

2 is a detailed block diagram of the coarse measuring instrument 100 and the ground measuring instrument 200 in the power measuring apparatus according to the embodiment of the present invention. 2, the coarse measuring instrument 100 includes a transformer 110, a current transformer 120, a ground potential detector 130, a power calculator 140, a controller 150, a display 160, and a communication unit 190 ).

The transformer 110 measures a voltage applied to the main line, and the current transformer 120 measures a current of the main line. In general, the current transformer 120 is used to measure a precise current value, and when measuring a large current, a wire-wound type or PCB type Rogowski coil may be used. When using a Rogowski coil, it is also possible to measure a current of 1 to 15 times the rated current. In addition, when a current transformer or a Rogowski coil is used, not only the current can be measured but also the occurrence of the overcurrent can be detected, thereby protecting the branch circuit. Various types of voltage sensors or current sensors may be used depending on the type and size of the voltage or current to be measured and the type of the measuring instrument. Accordingly, the internal configuration of the coarse measuring instrument 110 of the present invention may be changed It is self-evident.

1)과 인입 전류의 위상(

2) 차이에 해당하는 위상차(

)를 구할 수 있으며, 이를 이용해서 주선의 유효 전력과 무효 전력을 정확히 계측하는 것이 가능하다. 영전위 검출부(130)는 변압기(110) 또는 변류기(120)의 후단에 연결될 수도 있고, 주선과 변압기(110) 또는 주선과 변류기(120) 사이에 연결될 수도 있을 것이다.The spontaneous voltage detector 130 measures the phase of a voltage input to the main line and generates a spontaneous voltage detection signal Zx having the same frequency as the voltage to be measured. At this time, the zero-current detection signal Zx is triggered (On or Off) based on the zero point that the polarity of the input voltage changes from (+) to (-) or changes from (-) to It will represent a square wave. The electromotive force detector 130 may be implemented using an Atmel AVR 182 Zero Cross Detector or Atmel M90E36A IC chip. The geomagnetism detection signal Zx is transmitted to the ground fault meter 200 through the communication unit 190 and is detected by the virtual voltage generator 270 of the ground fault meter 200 using the received ground detection signal Zx A virtual voltage having the same phase and frequency as the voltage is generated. It is possible to measure the frequency and phase of the pull-in voltage or the pull-in current through the zero-potential detector 130. Therefore, the input voltage and phase (

1) and the phase of the inrush current

2) phase difference corresponding to the difference (

), And it is possible to accurately measure the active power and the reactive power of the main line. The ground potential detector 130 may be connected to the rear end of the transformer 110 or the current transformer 120 and may be connected between the main line and the transformer 110 or between the rectifier and the current transformer 120.

)를 고려한 유효 전력을 계산하고자 하는 경우에는 영전위 검출부(130)를 통하여 측정된 위상차(

)를 반영하여 전압값(V) * 전류값(I) * cos

에 해당하는 유효 전력을 계산할 수 있을 것이다. 물론, 전압값(V) * 전류값(I) * sin

에 해당하는 무효 전력을 계산하는 것도 가능하다.The power calculation unit 140 may calculate the power using the voltage value measured at the transformer 110 and the current value measured at the current transformer 120. If the phase of the voltage and the current flowing into the main line is not taken into consideration, it is possible to calculate the apparent power corresponding to the voltage value (V) * the current value (I), and the phase difference

), It is necessary to calculate the phase difference measured through the electromotive force detector 130

) * Voltage value (V) * current value (I) * cos

Can be calculated. Of course, the voltage value V * the current value I * sin

It is also possible to calculate the reactive power corresponding to the value of the reactive power.

The display unit 160 may display the voltage value or the current value of the main line or the power value calculated by the power calculation unit 140 and the amount of power (power value * time) used for a predetermined time. The display unit 160 may include a light emitting diode (LED), a liquid crystal display (LCD), a thin film transistor-liquid crystal display (TFT LCD), an organic light-emitting diode (OLED), flexible display, 3D display (3D display), or 7 segment (7 segment).

The communication unit 190 transmits the ground level detection signal Zx generated through the ground level detection unit 130 to the ground level measurement unit 200 using wire or wireless communication. When wired communication is used to transmit the over-current detection signal Zx, a wired communication method such as RS-485, RS-232 or RS-422 may be used. In case of using wireless communication, It is possible to use various wireless communication technologies such as Near Field Communication (NFC), ZigBee, Magnetic Secure Transmission (MST), Beacon, Ethernet, or WiFi.

)를 이용한 유효 전력을 계산하도록 전력 계산부(140)를 제어한다. 또한, 전력 계산부(140)의 결과값이 표시부(160)를 통해 표시될 수 있도록 하고, 영전위 검출부(130)를 통해 생성된 영전위 검출 신호(Zx)가 통신부(190)를 통해 지선 계측기(200)로 전달되도록 한다.The control unit 150 compares the apparent voltage and the apparent voltage using the voltage value and the current value measured through the transformer 110 and the current transformer 120 or the voltage value and the phase difference

The power calculation unit 140 controls the power calculation unit 140 to calculate the active power using the received power. The result of the power calculation unit 140 may be displayed through the display unit 160 and the geomagnetism detection signal Zx generated through the geomagnetism detection unit 130 may be transmitted through the communication unit 190, (200).

The controller 150 may include an arithmetic logic unit (ALU) for performing calculations, a controller for temporarily storing data and instructions, and a controller for processing the overall operation of the coarse measuring instrument 100. The control unit 150 may be implemented by a microprocessor such as Alpha of Digital, MIPS technology, MIPS of NEC, IDT, Siemens, Intel and Cyrix, Micro controller of ST, AMD and Nexgen ) And x86 of IBM and PowerPC of Motorola, which have a variety of architectures.

Although not shown in FIG. 2, the coarse measuring instrument 100 of the present invention may further include a memory for storing the calculated apparent power or active power. At this time, the memory generally stores data such as RAM (Random Access Memory) and ROM (Read Only Memory), SRAM (Static Random Access Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory) A high-speed main memory in the form of a medium and a memory such as a floppy disk, a hard disk, a tape, a CD-ROM, a flash memory, a multimedia card micro type, a card type memory (for example, SD or XD memory) An auxiliary memory in the form of a long term storage medium, and an apparatus for storing data using electrical, magnetic, optical or other storage media.

The control unit 150 may include an operating system (OS) and at least one application program. The OS is a set of software that controls the operation of the coordination meter 100 and the designation of resources. An application program is a set of software for performing a task requested by a user by using available computer resources through the OS. The OS and application programs will reside in memory. In accordance with the experience of one of ordinary skill in the art of computer programming, unless stated otherwise, the present invention will be described in accordance with the representation symbols for operations and operations performed by the power measuring device 300. This operation is computer-based and will be performed by an OS or a suitable application program. These operations and functions are not limited to the processing of the control unit 150 for the electrical signals such as the data bits causing the conversion or blocking of the electrical signals and the operation of the coarse measuring instrument 100, And management. A memory area in which a data bit signal is managed is a physical area having electric, magnetic, or optical characteristics corresponding to data bits.

The branch line meter 200 may include a current transformer 220, a power calculation unit 240, a virtual voltage generation unit 270, a display unit 260, a control unit 250, and a communication unit 290.

The current transformer 220 measures the value of the current drawn into the branch line. The power measuring apparatus 300 of the present invention generates a virtual voltage having the same frequency and phase as the main line voltage by using the ground level detection signal Zx transmitted from the main line meter 100 and calculates the power using the virtual voltage Therefore, a separate transformer 110 may not be provided. In the case where the ground potential measuring apparatus 200 generates a virtual current by using the inductance current of the main line to generate the ground potential detecting signal, the current transformer 220 may be omitted and a structure including a transformer may be used.

The communication unit 290 receives the over-current detection signal Zx transmitted from the coordination measuring instrument 100 by using wired communication or wireless communication.

The virtual voltage generator 270 generates a virtual voltage by using the ground potential detection signal Zx received through the communication unit 290. The virtual voltage has the same phase and frequency as the over-current detection signal Zx and can be adjusted to have a peak value corresponding to the magnitude of the rated voltage input through the main line. It could be 110V or 220V for home voltage, or 380V or 440V for factory voltage. Also, the virtual voltage may be a square wave having the same form as the over-current detection signal Zx, but it may be converted into a sinusoidal wave if necessary.

)를 반영하여 유효 전력을 계산할 수도 있고, 필요에 따라 피상 전력을 계산할 수도 있다. 동일한 피크값을 가지는 구형파의 실효값(Root Mean Square; RMS)이 정현파의 실효값보다 루트2(√2)배 만큼 크기 때문에, 구형파에 해당하는 가상 전압을 이용하는 경우에는 구형파 전력값을 루트2(√2)로 나누면 정현파에 해당하는 전력값을 계산할 수 있게 된다.The power calculation unit 240 calculates the power used in the branch line by using the current value measured at the current transformer 220 and the virtual voltage generated at the virtual voltage generation unit 270. Since the virtual voltage has the same frequency and phase as the voltage applied to the main line, the phase difference (

), And may calculate the apparent power, if necessary. Since the root mean square (RMS) of the square wave having the same peak value is larger than the effective value of the sine wave by the root 2 (√2) times, when the virtual voltage corresponding to the square wave is used, √2), the power value corresponding to the sine wave can be calculated.

The display unit 260 may display a power value or a power amount calculated by the power calculation unit 240, a current value measured by the current transformer 220, and the like.

The control unit 250 controls the virtual voltage generator 270 to receive the overvoltage detection signal Zx from the coaxial measurement apparatus 100 through the communication unit 290, So as to generate a virtual voltage having the same frequency and phase as the voltage. Also, the power calculator 240 controls the power value and the like calculated by the power calculator 240 to be displayed externally through the display 260.

The control unit 250 of the branch measuring apparatus 200 includes an ALU for performing calculations as well as a control unit 150 of the coarse measuring apparatus 100 and a register for temporary storage of data and commands, And a controller for processing the operation. Further, the branch wire measuring instrument 200 may further include a memory for storing the calculated apparent power, active power, and the like.

3 is a signal waveform diagram of a process of generating a zero-potential detection signal and a virtual voltage in the power measuring apparatus according to the embodiment of the present invention. In FIG. 3, a description will be made of an example in which the detection of electromotive force is performed with respect to a sine wave voltage that is introduced into a main line.

1)가 인입되는 전압의 위상에 해당하게 된다. 따라서, 주선 계측기(100)의 영전위 검출부(130)를 통하여 주선에 인입되는 전압의 영전위를 검출하면 (-) 값에서 (+) 값으로 상승하는 영전위 지점(Z1, Z2,..)에서 (+) 값으로 트리거되는 구형의 영전위 검출 신호(Zx)가 생성된다. 영전위 검출 신호(Zx)에서 (-) 값으로 트리거되는 시점은 주선의 인입 전압이 (+) 값에서 (-) 값으로 하강하는 영전위 지점이 될 것이다. 결국, 영전위 검출부(130)를 통해 생성되는 신호는 주선의 인입 전압과 동일한 주파수 및 위상을 가지는 구형파가 되는 것이다. The voltage of the sinusoidal wave flowing in the main line has a sine curve and alternately has (+) and (-) values. At this time, the time between the first Zero potential point (Z1) where the sine wave voltage increases from (-) to (+) and the second Zero potential point (Z2) The interval corresponds to one period (T), and the frequency has a value of 1 / T. Then, one period (T) of the sinusoidal wave is regarded as a phase of 360 degrees, and an angle to the first zero potential point (Z1)

1) corresponds to the phase of the incoming voltage. Therefore, when the potential of the voltage inputted to the main line is detected through the ground potential detector 130 of the coarse measuring instrument 100, the ground potential Z1, Z2, ... rising from the (-) value to the (+ A spherical ground potential detection signal Zx triggered by a (+) value is generated. The time point triggered by the negative potential detection signal (Zx) will be the zero potential point where the lead-in voltage decreases from (+) to (-). As a result, the signal generated through the spontaneous voltage detector 130 becomes a square wave having the same frequency and phase as the lead-in voltage of the main line.

The peak value Vpeak of the zero point detection signal Zx may be different from the peak value of the lead voltage of the main line but may be adjusted to have the same peak value by reflecting the magnitude of the rated voltage inputted to the main line, ), And a waveform having a fixed value may be generated, and the waveform may be corrected to an original value through calculation later. For example, by adding an amplifier circuit to the virtual voltage generator 270, the peak value of the virtual voltage 2 can be adjusted to be equal to the peak value Vpeak of the input voltage. Of course, the peak value of the over-current detection signal Zx may be generated to be equal to the peak value Vpeak of the lead-in voltage by changing through the setting of the detector or IC chip constituting the over-potential detector 130. [ In this manner, the zero-state detection signal Zx generates a rectangular-wave virtual voltage Vx having the same frequency, phase, and peak value as the lead-in voltage of the main line through the virtual voltage generator 270. Of course, the virtual voltage Vx may be a spherical file that is the same as the overvoltage detection signal Zx, but may be a sinusoidal wave, a triangular wave, a rectified wave or the like depending on the internal configuration of the circuit or the virtual voltage generator 270 of the ground potential detector 130 And may be generated in various types of waveforms.

Since the zero voltage detection signal Zx and the virtual voltage Vx are signals independent of the lead voltage of the main line, even if distortion or noise occurs in a certain period of the lead voltage, the zero voltage detection signal Zx and the virtual voltage Vx, It is possible to maintain a stable waveform irrespective of such distortion or noise. Therefore, even when the leading-in voltage is distorted or noise is generated, the ground-line measuring device 200 can generate a stable virtual voltage Vx having the same frequency, phase and the same peak value as the main lead-in voltage, Accurate and stable power calculation becomes possible.

FIG. 2 is a schematic diagram of a main line measuring apparatus according to an embodiment of the present invention. The main line measuring apparatus 100 measures a direct current input and an input voltage by using a current transformer 120 and a transformer 110, And generates a virtual voltage, and measures the electric power by measuring the incoming current of the branch wire through the current transformer 220. However, since the virtual voltage can be generated using the galvanometer detector 130 provided in the coaxial measuring instrument 100, the coaxial measuring instrument 100 can measure the coaxial power using the virtual voltage generator instead of the transformer 110 It is also possible to do.

4 is a block diagram showing the case where the virtual voltage generators 170 and 270 are provided on both the main measuring instrument 100 and the ground wire measuring instrument 200 as described above. FIG. 4 shows a case where the transformer 110 is replaced with the virtual voltage generator 170 in the coaxial meter 100 of FIG. Since the configuration of the transformer 110 and the virtual voltage generator 170 of the coaxial measuring instrument 100 are different from each other, description of the same components as those of FIG. 2 will be omitted.

The coarse measuring instrument 100 includes a current transformer 120, a ground potential detection unit 130, a virtual voltage generation unit 170, a power calculation unit 140, a display unit 160, a control unit 150, and a communication unit 190 can do.

The current transformer 120 and the ground potential detector 130 perform the same functions as those described with reference to FIG. The virtual voltage generator 170 generates the virtual voltage Vx by using the zero point detection signal Zx generated by the zero point detector 130. [ As described in FIG. 3, the virtual voltage Vx has the same phase and frequency as the lead-in voltage, and can be adjusted to have the same peak value as the lead-in voltage.

)를 알 수 있으므로, 이를 반영하여 유효 전력을 계산할 수도 있고, 필요에 따라 무효 전력 및 피상 전력을 계산할 수도 있다. 가상 전압(Vx)이 구형파인 경우에는 이를 통해 계산된 전력값을 루트2(√2)로 나누어 정현파에 해당하는 전력값을 계산할 수 있을 것이다.The power calculation unit 140 calculates the power using the current value measured at the current transformer 120 and the virtual voltage Vx generated at the virtual voltage generation unit 170. At this time, the phase difference (?) Corresponding to the phase difference between the pull-in voltage and the pull-in current

Therefore, it is possible to calculate the effective power in accordance with this, and to calculate the reactive power and the apparent power as necessary. When the virtual voltage Vx is a square wave, the power value corresponding to the sinusoidal wave can be calculated by dividing the calculated power value by the root 2 (2).

The power measuring apparatus of the present invention can also detect the zero electric potential in the ground fault meter 200 and generate the virtual voltage Vx from the zero point detection signal Zx in the coaxial measuring instrument 100 to calculate the power value of the coaxial line It will be possible.

FIG. 5 is a detailed block diagram of a power measuring apparatus according to another embodiment of the present invention, in which the virtual measuring device 100 includes a virtual voltage generating unit. 5, the power measuring apparatus 300 of the present invention may include a ground potential measuring unit 230 and a virtual voltage generating unit 170. The virtual voltage generating unit 170 may be included in the main measuring instrument 100 .

The line measuring device 200 may include a transformer 210 and a current transformer 220, a ground potential detecting unit 230, a power calculating unit 240, a control unit 250, a display unit 260, and a communication unit 290 . Therefore, the line measuring device 200 calculates the power value in the power calculating unit 240 using the line voltage value and the ground line current value measured through the transformer 210 and the current transformer 220, To be displayed outside. The ground level detection signal Zx generated by the ground level meter 200 is transmitted to the ground level meter 100 through the communication unit 290.

The coaxial measuring instrument 100 receives the zero potential detection signal Zx through the communication unit 190 and the virtual voltage generator 170 generates the virtual voltage Vx using the zero potential detection signal Zx. The virtual voltage Vx has the same phase and frequency as the overvoltage detection signal Zx and can be adjusted to have a peak value corresponding to the magnitude of the branch line voltage measured in the branch line. The virtual voltage Vx may be a square wave having the same form as the over-current detection signal Zx, but it may be converted into a sinusoidal wave or other waveform if necessary.

)를 반영하여 유효 전력을 계산할 수도 있고, 필요에 따라 피상 전력을 계산할 수도 있다. 마찬가지로, 구형파에 해당하는 가상 전압(Vx)을 생성하는 경우에는 전력 계산값을 루트2(√2)로 나누면 정현파에 해당하는 전력값을 계산할 수 있게 된다.The power calculation unit 140 can calculate the power used in the main line by using the current value of the main line measured by the current transformer 120 and the virtual voltage Vx generated by the virtual voltage generation unit 170. [ Since the virtual voltage Vx has the same frequency and phase as the branch line voltage of the branch line meter 200, the phase difference ("

), And may calculate the apparent power, if necessary. Similarly, when a virtual voltage Vx corresponding to a square wave is generated, a power value corresponding to a sinusoidal wave can be calculated by dividing the power calculation value by the root 2 (2).

5 is a graph showing the relationship between the ground potential and the ground voltage measured by the ground fault meter 200 using the current transformer 220 and the transformer 210. The ground potential is measured through the ground potential detector 230, And generates a virtual voltage Vx by receiving the zero potential detection signal Zx from the coarse measuring instrument 100 and calculates the power by measuring the current of the coaxial line through the current transformer 120. [ However, it is also possible to measure the power of the branch line using the virtual voltage generator in the branch line measuring instrument 200. [ 6 is a block diagram showing the case where the ground voltage measuring unit 200 includes a virtual voltage generating unit 170 and 270 both in the main line measuring apparatus 100 and the ground line measuring apparatus 200, . FIG. 6 shows that the transformer 210 is replaced with the virtual voltage generator 270 in the ground wire measuring apparatus 200 of FIG.

The branch wire measuring instrument 200 includes a current transformer 220 and a ground potential detector 230, a virtual voltage generator 270, a power calculator 240, a display 260, a controller 250 and a communication unit 290 can do.

The current transformer 220 and the ground potential detector 230 perform the same functions as those described with reference to FIG. The virtual voltage generator 270 generates a virtual voltage Vx by using the ground level detection signal Zx generated by the ground level detector 230. [ The virtual voltage Vx has the same phase and frequency as the branch line voltage and can be adjusted to have the same peak value as the branch line voltage.

)를 알 수 있으므로, 이를 반영하여 유효 전력을 계산할 수도 있고, 필요에 따라 피상 전력을 계산할 수도 있다. 가상 전압(Vx)이 구형파인 경우에는 이를 통해 계산된 전력값을 루트2(√2)로 나누어 정현파에 해당하는 전력값을 계산할 수 있을 것이다.The power calculation unit 240 calculates the power using the current measured by the current transformer 220 and the virtual voltage Vx generated by the virtual voltage generator 270. [ At this time, the phase difference (?) Corresponding to the phase difference between the branch line voltage and the branch line current

Therefore, it is possible to calculate the effective power by reflecting this, and to calculate the apparent power as necessary. When the virtual voltage Vx is a square wave, the power value corresponding to the sinusoidal wave can be calculated by dividing the calculated power value by the root 2 (2).

7 is a flowchart of a power measurement method according to an embodiment of the present invention. FIG. 7 shows a method of measuring power of a main line and a branch line in the structure of the power measuring apparatus of FIG. 2;

)를 알 수 있기 때문에, 유효 전력이나 무효 전력, 피상 전력을 각각 계산할 수도 있다.The power measurement method of the present invention can be divided into an operation performed by the coarse measuring instrument 100 and an operation performed by the branch wire measuring instrument 200. [ The coaxial measuring instrument 100 measures the current of the coaxial line through the current transformer 120 and measures the coaxial voltage through the transformer 110 (S20). The coarse measuring instrument 100 can calculate the power value of the coarse line or the amount of power of the coarse line using the measured coarse line current and the coarse line voltage (S30). The coarse measuring instrument 100 detects the potential of the coarse voltage or the coarse current signal through the coarse detection unit 130 (S40). The geomagnetic detection signal Zx generated by the geomagnetism detection unit 130 may be a square wave having the same phase and frequency as the main line voltage or the main line current to be detected. On the other hand, when the zero-current detection signal Zx is used in the step S30 of calculating the power of the main line, the phase difference between the voltage and the main line

), It is possible to calculate the active power, the reactive power, and the apparent power, respectively.

)를 알 수 있기 때문에, 유효 전력이나 무효 전력, 피상 전력을 각각 계산할 수 있다.The zero-current detection signal Zx generated by the coarse measuring instrument 100 is transmitted to the branch wire measuring instrument 200 using wired or wireless communication (S60). The branch line measuring instrument 200 generates the virtual voltage Vx using the zero-current detection signal Zx (S70). The virtual voltage Vx can be adjusted to have the same peak value Vpeak as the lead-in voltage of the main line. Since the phase, frequency, and peak value of the generated virtual voltage Vx are the same, it is possible to calculate the power of the branch line using the virtual voltage Vx without separately measuring the branch line voltage. Accordingly, the branch wire measuring instrument 200 measures the ground wire current value through the current transformer 220, and calculates the power value or the power amount of the branch wire using the generated virtual voltage Vx in step S80. At this time, in step S90 of calculating the power of the branch line, the phase difference between the voltage and the current of the main or branch line from the virtual voltage Vx

), It is possible to calculate the active power, the reactive power and the apparent power, respectively.

Although FIG. 7 illustrates the operation of the power measuring apparatus shown in FIG. 2, similar power and voltage detection and virtual voltage generation and power calculation processes will also be performed in the case of the power measuring apparatuses of FIGS. However, depending on the positions of the electromotive force detector and the virtual voltage generator, the electromotive force detection or the virtual voltage generation operation may be performed on one side of the main measuring instrument 100 or the branch measuring instrument 200, There will be.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, . Therefore, it should be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

10: main-circuit breaker 20: sub-circuit breaker
100: Arranged measuring instrument 200: Ground measuring instrument
110, 210: Transformer 120, 220: Current transformer
130, 230: an electromotive force detector 140, 240:
150, 250: a control unit 160, 260:
170, 270: virtual voltage generator
190, 290: communication unit 300: power measuring device

Claims (26)

1. An apparatus for measuring an electric power of a branch line and branches branched therefrom,
A coarse measuring unit provided in the coarse line to generate a coarse current detection signal from a voltage signal input to the coarse line; And
And a branch line meter installed at the branch line and calculating power of the branch line using the virtual voltage generated using the ground level detection signal transmitted from the main line measuring instrument and the current measured at the branch line,
A voltage generator for generating a rectangular-wave virtual voltage having the same phase, frequency, and peak value as the voltage drawn into the main line from the ground potential detection signal; And a power calculation unit calculating the power of the branch line using the measurement result of the current transformer and the virtual voltage.
The method according to claim 1,
Wherein the zero potential detection signal is a square wave having a frequency and a phase the same as a voltage signal input to the main line, the polarity of a voltage signal input to the main line being changed.
The method according to claim 1,
The coarse measuring device includes: a voltage measuring unit for measuring a voltage of the coarse line;
A current measuring unit for measuring a current of the main line; And
And a power calculation unit for calculating a power of the main line using the measurement results of the voltage measurement unit and the current measurement unit.
The method of claim 3,
Wherein the current measuring unit comprises a current transformer or a Rogowski coil.
The method of claim 3,
Wherein the power calculator calculates the active power, the reactive power, or the apparent power by reflecting the phase difference between the voltage and the current drawn into the main line from the electromotive force detection signal.
The method of claim 3,
And the coarse measuring instrument further comprises a display unit for displaying the calculated power value.
The method according to claim 1,
And the coarse measuring instrument includes a transmitter for transmitting the geomagnetic detection signal to the ground wire measuring instrument.
8. The method of claim 7,
Wherein the transmitter comprises one of a RS-485, RS-232, and RS-422 communication wired communication module.
8. The method of claim 7,
The transmitter may be configured to transmit power, which is one of a wireless communication module such as Bluetooth, NFC (Near Field Communication), ZigBee, MST (Secure Transmission), Beacon, Ethernet or WiFi Measuring device.
delete delete delete delete delete delete delete 1. An apparatus for measuring electric power installed on a branch line,
A current measuring unit for measuring a current of the branch line;
A communication unit for receiving a ground potential detection signal generated from a coarse voltage signal from a coarse measuring instrument provided on a coarse line;
A virtual voltage generator for generating a rectangular-wave virtual voltage having the same phase, frequency, and peak value as the voltage input to the main line from the zero-potential detection signal; And
And a power calculation unit calculating the power of the branch line using the measurement result of the current measurement unit and the virtual voltage.
1. An apparatus for measuring an electric power of a branch line and branches branched therefrom,
A branch line meter installed on the branch line to generate a zero potential detection signal from a voltage signal input to the branch line; And
And a coarse measuring instrument installed in the coarse line and calculating a coarse line power using a virtual voltage generated using the coarse detection signal transmitted from the ground wire measuring device and a current measured in the coarse line,
A virtual voltage generator for generating a rectangular-wave virtual voltage having the same phase, frequency, and peak value as the voltage drawn to the branch line from the geomagnetism detection signal from the geomagnetism detection signal; And a power calculation unit for calculating the power of the main line using the measurement result of the current transformer and the virtual voltage.
delete 1. An apparatus for measuring electric power installed on a main line,
A current measuring unit for measuring a current of the main line;
A communication unit for receiving a ground potential detection signal generated from a voltage signal of a branch line from a branch line instrument installed on a branch line;
A virtual voltage generator for generating a rectangular wave virtual voltage having the same phase, frequency, and peak value as the voltage input to the branch line from the geomagnetism detection signal; And
And a power calculation unit for calculating a power of a main line using the measurement result of the current measurement unit and the virtual voltage.
1. A method for measuring power of a branch line and branches branched therefrom,
Generating an over-current detection signal from a voltage signal inputted to the main line in a main line measuring instrument provided on the main line;
Transmitting the ground potential detection signal to a branch wire measuring instrument installed on the branch line;
Receiving a ground potential detection signal transmitted from the coarse measuring instrument in a ground wire measuring instrument installed on the branch wire;
Generating a rectangular-wave virtual voltage having the same phase, frequency, and peak value as the voltage input to the main line using the geomagnetism detection signal; And
And calculating the power of the branch line using the virtual voltage and the current measured at the branch line.
delete A method for measuring power in a branch wire measuring instrument installed on a branch line,
Measuring a current of the branch line;
Receiving a ground potential detection signal generated from a coarse voltage signal from a coarse measuring instrument provided on a coarse line;
Generating a rectangular-wave virtual voltage having the same phase, frequency, and peak value as the voltage drawn into the main line from the zero-potential detection signal; And
And calculating the power of the branch line using the measured current and the virtual voltage.
1. A method for measuring power of a branch line and branches branched therefrom,
Generating a zero-potential detection signal from a voltage signal input to the branch line at a branch line measuring instrument installed on the branch line;
Transmitting the geomagnetic detection signal to a coarse measuring instrument provided on the coarse line;
Receiving a ground potential detection signal transmitted from the ground wire measuring instrument at a coaxial measuring instrument installed on the coaxial cable;
Generating a rectangular-wave virtual voltage having the same phase, frequency, and peak value as the voltage input to the branch line using the geomagnetism detection signal; And
And calculating the power of the main line using the virtual voltage and the current measured in the main line.
delete 1. A method for measuring power in a coaxial line measuring instrument installed on a coaxial line,
Measuring a current of the main line;
Receiving a ground potential detection signal generated from a voltage signal of a branch line from a branch line instrument installed on a branch line;
Generating a virtual voltage having a square wave virtual voltage having the same phase, frequency, and peak value as the voltage drawn to the branch line from the geomagnetism detection signal; And
And calculating the power of the main line using the measured current and the virtual voltage.

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