KR20210017201A - An apparatus for measuring power having a separated structure - Google Patents

Abstract

The present invention relates to a separable-type power measuring device comprising: a meter which measures information transmitted from a CT current sensor; a voltage sensor disposed separately from the CT current sensor; a modulator modulating the current outputted from the CT current sensor in an analog manner; and a demodulator demodulating a current sensing signal modulated by the modulator in the analog manner. Accordingly, by configuring the device by separating the CT current sensor and the voltage sensor, an interference problem caused by the coexistence of multiple devices can be improved.

Description

Separate power measuring device{AN APPARATUS FOR MEASURING POWER HAVING A SEPARATED STRUCTURE}

The present invention relates to a separate type power measurement apparatus, and more particularly, to a separate type power measurement apparatus having a structure without interference while separating a CT current sensor and a voltage sensor and connecting wirelessly.

In places where electricity is used such as homes or factories, meters are installed to check the used power, and it is common to charge usage fees according to the amount of power consumption measured by the meter. The watt-hour meter can be classified into a mechanical watt-hour meter and an electronic watt-hour meter according to its operation method or type. Recently, an electronic watt-hour meter is preferred in consideration of accuracy and effectiveness. In particular, electronic watt-hour meters, including smart meters, have also been incorporated into legal meters, enabling additional services such as remote meter reading or power consumption analysis to generate power saving guides, and demand responses that enable power use analysis.

Electronic watt-hour meters, including conventional smart meters, include CT current sensors. (Patent Document 1) Since such a conventional CT sensor must be installed in the power system inside the distribution panel, it is generally installed outside the power meter body and is connected to the body by wire. At this time, due to the narrow space inside the distribution panel and the connection wire between the CT current sensor and the watt-hour meter body, the connection wire must undergo a complicated installation process, such as having to arrange the wires. Therefore, there were many cases where the increase in cost due to the installation of professional engineers was larger than the main body price of the smart meter, because professional engineers for installation had to go on a business trip.

Therefore, for the commercialization of watt-hour meters including smart meters, technologies for solving the above installation cost increase have been urgently required.

KR10-1555942B

Accordingly, the inventors of the present invention invented a separate power measurement device that minimizes installation cost while shortening installation time through maximization of installation ease. That is, another problem to be solved by the present invention is to provide a detachable measuring device that simplifies the structure so that it can be installed without the help of an expert, thereby reducing the installation time and facilitating diffusion of the device.

However, in order to implement this, when the CT current sensor and the voltage sensor are separated and the devices are wirelessly connected, a number of devices coexist around them. For example, in the case of a multi-family house such as an apartment, a problem of interference occurs because the number of wireless CT sensors in the vicinity increases. In this case, it is also a problem to be solved in the present invention to provide a separate power measurement device capable of improving the interference problem caused by coexistence of a plurality of wireless CT sensors.

In addition, another problem to be solved by the present invention is to provide a separate measuring device capable of minimizing the interference problem due to multiple paths when configuring the device to be wirelessly connected by separating the CT current sensor and the voltage sensor.

The problems of the present invention are not limited to the problems mentioned above, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to solve the above-described problems, a separate power measurement apparatus according to an embodiment of the present invention includes: a meter that measures information transmitted from a CT current sensor; A voltage sensor disposed separately from the CT current sensor; And a modulator for modulating the current output from the CT current sensor in an analog manner. And a demodulator for demodulating the current sensing signal modulated by the modulator in an analog manner. Accordingly, by simplifying the structure, it is possible to install it without the help of an expert, so that the spread of the device can be maximized as the installation becomes easy.

According to another feature of the present invention, the modulator may be disposed on one side of the CT current sensor, and the demodulator may be disposed in the meter.

According to another feature of the present invention, in order to transmit the output of the sensor without distortion, the modulator and demodulator are configured by a modulation method of AM (Amplitude Modulation) or FM (Frequency Modulation), and the sensor having information related to the amount of power to be modulated is The signal can be transmitted to the user terminal using a wireless transmission medium or a wired transmission medium.

According to another feature of the present invention, the voltage sensor is mounted on an indoor power socket in the form of a plug, and the current sensor is located in a distribution board where it is easy to measure the total amount of indoor power consumption, and the voltage sensor and the current sensor Analog modulation methods such as AM, FM and PM can be used for synchronization and transmission of measurement information.

According to another feature of the present invention, in the modulation scheme using AM, any one of a PN code and a hopping pattern is applied to each transmission/reception pair to prevent interference, and the modulation scheme using FM is used to prevent interference. Any one of a chirp pattern and a hopping pattern may be applied for each transmission/reception pair.

In order to solve the above-described problems, a separate power measurement system according to an embodiment of the present invention includes a modulator for modulating a current output from a CT current sensor disposed at one side of the separate power measurement system into an AM signal or an FM signal; A pattern generator that generates unique information by classifying a plurality of sensors, a demodulator that demodulates a signal modulated in response to the modulator and inputs a current signal from a transmitting side; And a power meter that performs power calculation based on the input current and the voltage of the voltage sensor, and a user terminal that receives the measured power information. Accordingly, by configuring the device by separating the CT current sensor and the voltage sensor, interference problems caused by the coexistence of a plurality of devices can be improved.

According to another feature of the present invention, when modulating with an AM signal or an FM signal, interference of multiple signals can be prevented by using any one of a PN code, a hopping pattern, and a chirp pattern.

According to another feature of the present invention, the CT current sensor and the voltage sensor may each have a separate arrangement.

Details of other embodiments are included in the detailed description and drawings.

The present invention can maximize the user's economic benefit by minimizing the installation cost while shortening the installation time.

According to the present invention, by separating the CT current sensor and the voltage sensor to configure the device, the interference problem caused by the coexistence of a plurality of devices can be improved.

The present invention simplifies the structure so that the installation can be performed without the help of an expert, so that the diffusion of the device can be maximized as the installation becomes easy.

However, the effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is an exemplary view illustrating a wireless transmission method using AM modulation according to an embodiment of the present invention.
2 is an exemplary diagram illustrating a structure of a CT current sensor and a wireless transmission method using analog modulation according to an embodiment of the present invention.
3 is an exemplary diagram showing a ring modulator according to an embodiment of the present invention.
4 is an exemplary diagram for explaining an FM modulation method according to another embodiment of the present invention.
5 is an exemplary diagram for explaining an FM modulation method according to another embodiment of the present invention.
6 is an exemplary diagram for explaining an FM modulation method according to another embodiment of the present invention.
7 is an exemplary view illustrating a method for preventing interference using a chirp pattern according to an embodiment of the present invention.
8 is an exemplary diagram for explaining a hopping pattern according to another embodiment of the present invention.
9 is a view in which a meter including a smart meter is installed in a distribution panel according to the prior art.

The following content merely illustrates the principle of the invention. Therefore, although those skilled in the art may implement the principles of the invention and invent various devices included in the concept and scope of the invention, although not clearly described or illustrated herein. In addition, it should be understood that all conditional terms and examples listed in this specification are, in principle, expressly intended only for the purpose of making the concept of the invention understood, and are not limited to the embodiments and states specifically listed as such. do.

In addition, in the following description, ordinal expressions such as first, second, etc. are intended to describe objects that are equivalent and independent of each other, and in the order of main/sub or master/slave It should be understood as meaningless.

The above-described objects, features, and advantages will become more apparent through the following detailed description in connection with the accompanying drawings, and accordingly, a person of ordinary skill in the technical field to which the invention pertains will be able to easily implement the technical idea of the invention. .

Each of the features of the various embodiments of the present invention can be partially or entirely combined or combined with each other, and as a person skilled in the art can fully understand, technically various interlocking and driving are possible, and each of the embodiments may be independently implemented with respect to each other. It may be possible to do it together in a related relationship.

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

Prior to the explanation, since the signal of a general CT current sensor is an analog signal, if it is transmitted as a digital signal through various conversion processes, it is unpredictable due to A/D conversion, processing delay, transmission delay, transmission control, etc. A time delay may occur. This delay element causes distortion of the measurement result due to the nature of the watt-hour meter that gives meaning to the measured value using voltage, current, and phase. Accordingly, transmission synchronization and interference control must be accompanied when transmitting the CT current sensor.

On the other hand, the separate power measurement system according to an embodiment of the present invention is generated by digitalizing the separately measured current data by applying a method of converting the current sensing signal to analog communication rather than to digital communication. There is an effect of preventing the delay phenomenon in advance and maximizing the ease of installation to increase the spread of the device to the public.

Hereinafter, a configuration of a separate power measurement system according to an embodiment of the present invention and a wireless transmission method using AM modulation will be described in detail with reference to FIGS. 1 to 3.

1 is an exemplary view illustrating a wireless transmission method using AM modulation according to an embodiment of the present invention. 2 is an exemplary diagram illustrating a structure of a CT current sensor and a wireless transmission method using analog modulation according to an embodiment of the present invention. 3 is an exemplary diagram showing a ring modulator according to an embodiment of the present invention. 4 is an exemplary diagram for explaining a method of preventing interference according to FIG. 1.

Referring to FIG. 1, a separate power measurement system according to an embodiment of the present invention includes a meter 100, a watt hour meter 110, a CT current sensor (CS), an AM modulator 130, an AM demodulator 140, and a current input. 120, a voltage sensor (VS), an operation unit 115, may include a plug (PL) and a terminal 200.

Referring to FIG. 1, the meter 100 may be connected to a CT current sensor CS, a plug PL, and a terminal 200. At this time, the meter 100 is located in an indoor environment, and preferably may be located in the distribution board. In this case, the meter 100 measures the current value passing through the conductor line in the distribution panel through the AM modulated signal, and then calculates it with the voltage value generated by the voltage sensor VS, and transmits the amount of power used to the terminal 200. have. Specifically, the current output from the CT current sensor CS is modulated by the AM modulator 130 into an AM modulated current sensing signal, and then demodulates the modulated current sensing signal using the AM demodulator 140.

The watt hour meter 110 is included in the meter 100, and specifically, calculates the power used based on the values of the voltage sensor VS and the CT current sensor CS, and outputs the calculated power to the communication unit 105. In this case, the calculation unit 115 calculates the amount of power based on the voltage value and current value input through the voltage sensor VS and the current input unit 120 and then outputs it to the communication unit 105. The operation unit 105 may be implemented with various devices such as a microprocessor or an application specific integrated circuit (ASIC), and the communication unit 105 may be various wireless communication means that can be connected to the user terminal 200 such as Bluetooth, LTE, and WiFi. . Alternatively, a wired configuration such as power line communication (PLC) is also possible.

At this time, the CT current sensor CS and the watt hour meter 110 are connected through wired/wireless communication, and the CT sensor CS may broadcast a current sensing value through the AM modulator 130. In this case, there is a possibility that interference may occur due to other wireless CT current sensors CS in the vicinity, and a solution to the interference problem will be described later. In the case of current value transmission using AM modulation, which is an embodiment of the present invention, the propagation delay within 100m is less than about 33ns between the CT current sensor (CS) and the voltage sensor in the watt hour meter 110, and the delay according to the current value transmission Since this hardly occurs, there is no problem even if the power value is calculated without separate synchronization.

Meanwhile, the CT current sensor CS is configured to detect a current applied through the power line 150 and is disposed on the AM modulator 130 side and may include a current transformer (CT). In addition, as shown in FIG. 2, the CT current sensor CS measures the secondary current induced by the magnetic force generated in the ferromagnetic core (ring shape) as the AC current flows through the power line 150. AC current can be measured according to the principle.

t)를 발진시키는 구성이다. 변압기(137)를 통하여 반송파와 전류센싱 신호는 믹싱된다. 따라서, CT전류센서(CS)에서 검출되는 전력선(150)의 교류 전류가 반송파(Acos

t)에 의해 브로드캐스팅될 수 있다. Referring to FIG. 3, the AM modulator 130 may include, for example, a detector 132 and an oscillator 135. Here, one side of the detector 132 and the oscillator 135 is connected to the CT current sensor CS, and the other side is connected to the transformer 137. The detector 132 is configured to detect the secondary current induced by the CT current sensor CS in the forward direction, and the oscillator 135 is a carrier wave (Acos

It is a configuration that oscillates t). The carrier wave and the current sensing signal are mixed through the transformer 137. Therefore, the AC current of the power line 150 detected by the CT current sensor CS is a carrier wave (Acos

can be broadcast by t).

t)와 믹싱되어 브로드캐스팅된다. 이 때, CT전류센서(CS)는 도 3에 도시된 바와 같이, 단순한 구조의 송신부로 구현될 수 있어, 설치의 용이성을 극대화할 수 있는 효과가 있다.That is, the secondary current induced by the alternating current of the power line 150 detected by the CT current sensor CS is a carrier wave (Acos) by the transformer 137 of the AM modulator 130

It is broadcast after mixing with t). At this time, the CT current sensor CS can be implemented as a transmission unit having a simple structure, as shown in FIG. 3, there is an effect of maximizing ease of installation.

However, if a plurality of CT current sensors (CS) coexist or the distance between the CT current sensor (CS) and the watt hour meter 110 is increased, the size of the AM modulated current sensing signal may need to be increased. Interference with nearby devices may occur. The configuration of interference prevention will be described later.

Referring back to FIG. 1, the voltage sensor VS may be connected to a commonly used plug PL. In the case of a household power source, it is connected to an indoor outlet to measure the change in voltage. In this case, installation can be quite easy. In this case, the plug PL is directly mounted in the meter 100 including the voltage sensor VS to maximize the ease of installation of the power measuring device.

The user terminal 200 may receive the power value measured by the watt hour meter 110. The power value may be received by being directly connected to a local network such as Bluetooth or WiFi, or the power value may be received through a separate server connected to the power meter 110. For example, the user terminal may be any terminal capable of computing, such as a mobile phone, a PC, or a tablet PC, and may be a service terminal using an app service.

Meanwhile, as mentioned above, a problem of interference may occur between the CT current sensor 130 and other nearby CT current sensors 130 or by other devices using a similar frequency. Therefore, a configuration for solving the problem of interference will be described below.

As shown in FIG. 4, interference problems can be prevented by using a PN (Pseudo Noise) code. Specifically, a unique PN code is allocated for each transmission/reception pair. At this time, since the PN code has its own characteristics, other receivers cannot receive other signals by the PN code assigned to each transmission/reception pair. That is, even if other signals that are not mutually agreed upon with other receivers are captured, they are treated as noise. In this case, the PN code is added to the current signal induced by the CT current sensor. For the sum of the PN code and the current signal, an adder such as a Modulo 2 Adder can be used.

Meanwhile, the AM modulator 130 modulates the sum of the PN code and the current signal with a carrier wave, and then broadcasts through the amplifier 470 and an antenna.

In addition, the receiver can extract the signal attenuation by using the auto-correlation characteristic of the PN code, and the time difference between the transmission time and the reception time can be known using the auto-correlation function of the PN code. Since time can be compensated, there is an effect of performing synchronization of measured values.

Accordingly, in the separate power measurement system according to an embodiment of the present invention, the PN code is added to the output signal of the CT current sensor from which the current to be measured flowing through the power line is extracted, modulated into an AM signal, and then transmitted through a wired/wireless transmission medium. Thus, a current signal with high reliability can be transmitted from the CT current sensor to the watt hour meter.

Hereinafter, an FM modulation method using a power line as a transmission medium according to another embodiment of the present invention and a method of preventing interference thereof will be described with reference to FIG. 5.

5 is an exemplary diagram for explaining an FM modulation method according to another embodiment of the present invention. In FIG. 5, only the modulation scheme is different from that of FIG. 1, and the rest of the configurations are substantially the same, so a redundant description will be omitted.

Referring to FIG. 5, the output current output from the CT current sensor CS is converted into an FM signal using the FM modulator 530 and then transmitted to the power line 155 through the first matching circuit 550. The maximum signal of the current sensing signal may be transmitted through the first matching circuit 550. In this case, the current output from the CS current sensor CS is modulated by the FM modulator 530 and then transmitted by wire through the power line 155 between the first and second matching circuits 550 and 560.

Meanwhile, the receiving side may receive the FM current signal of the corresponding frequency band through the second matching circuit 560, and the received FM current signal is demodulated into a current sensing signal through the FM demodulator 540. In addition, the demodulated current sensing signal is changed into a form that can be calculated by the operation unit 115 by the current input unit 120. For example, as for the current sensing signal, an analog signal may be converted into a digital form by the current input unit 120. Even if the transmission is wired through the configuration of the present invention, since FM modulation is performed, interference with the 60Hz system voltage of the power line does not occur.

At this time, each matching circuit (550, 560) matches the FM modulated signal frequency based on the power transmission condition suitable for the corresponding frequency, and the CT current sensor (CS) in the form of a transformer acts as an antenna tuned to the carrier frequency of the internal RF circuit. Perform.

Accordingly, the separate power measurement system according to another embodiment of the present invention can perform synchronization without delay while having high reliability by converting into an FM signal using a power line and transmitting it to a user terminal (or server) through calculation of power amount. have.

Hereinafter, an FM modulation scheme capable of preventing interference using an FM antenna using a wireless environment as a transmission medium according to another embodiment of the present invention will be described with reference to FIGS. 6 and 7.

6 is an exemplary diagram for explaining an FM modulation method according to another embodiment of the present invention. 7 is an exemplary diagram for explaining a method of preventing interference by applying a chirp pattern. Only the transmission method is different from those of FIGS. 6 and 4 to 5, and the remaining configurations are substantially similar, so a redundant description will be omitted.

Referring to FIG. 6, a separate power measurement system according to another embodiment of the present invention uses a plurality of connectivity wireless communications. Here, the connectivity wireless communication performs wireless communication using an FM antenna. In other words, the output current output from the CT current sensor CS is converted into an FM signal using the FM modulator 530, and then transmitted and demodulated wirelessly through the FM demodulator 540 using the FM antenna. Thereafter, the information calculated through the power amount calculation is transmitted to the user terminal.

Accordingly, the FM modulation scheme using an FM antenna according to another embodiment of the present invention can simplify a structure and achieve high reliability. In addition, synchronization without delay can be performed. However, this embodiment shows a case where the voltage sensor VS directly measures the voltage through the power lines 150 and 155, but as in the embodiment of FIG. 1, the voltage is measured through the indoor plug PL. It is also possible.

However, even with the same analog modulation method, when FM modulation is used, the effect of signal attenuation compared to AM modulation is very small, and it is characterized by strong interference from external signals. In addition, in terms of interference prevention and synchronization, a new approach that provides device uniqueness is possible by varying the frequency change pattern.

For example, as shown in FIG. 7, interference problems may be prevented by using a chirp pattern.

Specifically, the FM modulator 530 allocates a unique chirp pattern for each transmission/reception pair. At this time, since the chirp pattern has its own characteristics, the other receiver cannot receive the signal transmitted from the present FM modulator 530 due to the chirp pattern assigned to each transmission/reception pair. In addition, there is an effect of preventing a transmission delay phenomenon by maintaining synchronization between transmission/reception using the start and end points of the chirp pattern.

The FM modulator 530 adds the chirp pattern and the current value measured by the CS current sensor CS, mixes the sum of the chirp pattern and the current value with an FM carrier, modulates it, and transmits it wirelessly through the amplifier 770. . By FM modulation, noise during transmission is greatly reduced, and the possibility of interference can be reliably prevented through an overlapping pattern for each transmission/reception pair.

8 is an exemplary view illustrating a method for preventing interference according to another embodiment of the present invention.

Referring to FIG. 8, a hopping pattern is differently allocated for each pair to perform communication. At this time, a PN code can be additionally used for each pair. In addition, another interference prevention method of the present invention can be applied to both AM communication and FM communication.

Accordingly, the interference prevention method according to another embodiment of the present invention can prevent interference by using the unique characteristics of the hopping pattern, and determine the compensation after determining the loss level using the characteristics of the autocorrelation function. In addition, synchronization can be performed using the autocorrelation function of the hopping pattern.

Although the embodiments of the present invention have been described in more detail with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be made without departing from the spirit of the present invention. . Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

100: meter 200: terminal
110: watt hour meter 120: current input
130: AM modulator 140: AM demodulator
550, 560: matching circuit 530: FM modulator
540: FM demodulator 770: amplifier
CS: CT current sensor VS: voltage sensor
PL: plug

Claims (8)

A meter for weighing information transmitted from the CT current sensor;
A voltage sensor disposed separately from the CT current sensor; And
A modulator that modulates the current output from the CT current sensor in an analog manner; And
Comprising a demodulator for demodulating the current sensing signal modulated by the modulator in an analog manner,
Detachable power measurement device. The method of claim 1,
The modulator is disposed on one side of the CT current sensor, and the demodulator is disposed in the meter,
Detachable power measurement device. The method of claim 1,
The modulator and the demodulator are driven by a modulation method of AM (Amplitude Modulation) or FM (Frequency Modulation),
The signal from the sensor with the information related to the amount of power to be modulated is transmitted to the user terminal using a wireless transmission medium or a wired transmission medium.
Detachable power measurement device.
Detachable power measurement device. The method of claim 1,
The voltage sensor is mounted in an indoor power socket in the form of a plug, and the current sensor is located in a distribution board where it is easy to measure the total amount of power consumption indoors, Using the analog modulation method of FM and PM,
Detachable power measurement device. The method of claim 3,
In the modulation scheme using the AM, any one of a PN code and a hopping pattern is applied for each transmission/reception pair to prevent interference,
In the modulation scheme using FM, any one of a chirp pattern and a hopping pattern is applied for each transmission/reception pair to prevent interference,
Detachable power measurement device. In the measurement system of the separate power measurement device,
A modulator that modulates the current output from the CT current sensor disposed at one side of the separate power measurement system into an AM signal or an FM signal;
A demodulator connected to the modulator to demodulate the modulated signal and input a current; And
Comprising a user terminal for receiving the measured power information by performing the power amount calculation based on the input current and the voltage of the voltage sensor,
Measurement system of separate power measuring devices. The method of claim 6,
When modulating with the AM signal or the FM signal, using any one of a PN code, a hopping pattern, and a chirp pattern to prevent crosstalk of multiple signals,
Measurement system of separate power measuring devices. The method of claim 6,
The CT current sensor and the voltage sensor each have a separate arrangement,
Measurement system of separate power measuring devices.

Images