CN100454025C - Energy Meter and Power Monitoring System - Google Patents

Abstract

An electric energy meter and a power monitoring system in the technical field of electronic instruments, the electric energy meter has two modules: a sensor module and a communication module, and the two modules are controlled by a microprocessor. The sensor module completes the sampling and calculation of electrical parameters, and the communication module completes data exchange with the sensor module and performs network communication processing through the TCP/IP protocol stack. The power monitoring system includes: an electric energy meter with a sensor module and a communication module, and a user monitoring device. The user monitoring device has an electric energy meter management module for displaying and storing data received from the communication module through the network, and for Energy meters are managed. The energy meter can simultaneously monitor and control multiple independent electrical equipment. The electric energy meter has a Web server and a power monitoring system, can transmit the collected electric parameters through the Internet, and can collect electric parameters for a long time and save them on the user's monitoring device.

Description

Energy Meter and Power Monitoring System

technical field

The invention relates to the technical field of electronic instruments, in particular to an electric energy meter and a power monitoring system, that is, an electric energy meter capable of performing power measurement processing, calculation processing, and network communication processing, and a power monitoring system equipped with the electric energy meter.

Background technique

In order to reduce the consumption of electric energy, it is necessary to accurately and cost-effectively measure the electric energy consumption of each electrical device or each specific area of a building. At present, there is a digital power meter equipped with a microprocessor as an electric energy meter for measuring the power of electric equipment. As shown in Japanese Patent Document 5-172859, the input voltage waveform and the input current waveform are picked up for A/D conversion, and the instantaneous power value is obtained according to the converted voltage and current data, and then the average power value during the signal acquisition period is calculated, and the average The product of power value and time is the energy value. The digital power meter can perform numerical sampling processing and electric energy calculation processing, and is characterized in that it can easily realize multi-system, and has higher precision than the mechanical induction power meter.

However, the above-mentioned digital power meter has no remote control function, so it is necessary to go to the site to read the power usage of the electrical equipment. In addition, the input voltage waveform and the input current waveform are not continuously sampled, but are sampled at regular intervals, so there may be errors in the sampled data.

Contents of the invention

The purpose of the present invention is to solve the deficiencies in the prior art, and provide an electric energy meter and a power monitoring system, which can monitor and control the power consumption of electrical equipment through the Internet, and have the characteristics of high precision and low cost.

The present invention is achieved through the following technical solutions:

The electric energy meter provided by the first aspect of the present invention has a sensor module and a communication module. The sensor module is used for sampling and processing the voltage and current signals of the electrical equipment, and using the sampled measurement values to perform calculation processing of current values, voltage values, and power values. The communication module is used for exchanging data with the sensor module and performing network communication processing through the TCP/IP protocol stack. The sampling and calculation processing of voltage and current in the sensor module, as well as the data exchange and network communication processing with the sensor module in the communication module are controlled by a microprocessor.

Usually, the sensor module of the electric energy meter uses a microprocessor to sample and process the voltage and current signals, and uses the sampled measured values to perform calculations on the current value, voltage value, and power value. The communication module is controlled by another microprocessor, completes the data exchange with the sensor module and performs network communication processing through the TCP/IP protocol stack.

However, the sensor module and the communication module in the electric energy meter proposed in the first aspect of the present invention share a microprocessor, that is, a microprocessor performs sampling processing of the voltage and current signals of the sensor module, and uses the sampled measured value to perform current processing. value, voltage value, power value calculation processing, and the communication module performs data exchange and network communication processing with the sensor module. Therefore, the price of the energy meter is greatly reduced.

In the electric energy meter proposed in the second aspect of the present invention, when the microprocessor executes the sampling processing process (P1) for the voltage and current, the calculation processing process (P2) and the communication module and The data exchange and network communication processing process (P3) of the sensor module is in a ready state, and when the operation processing process (P2) is executed, the voltage and current sampling processing process (P1) and the communication module and the sensor module are The data exchange and network communication processing process (P3) is in a ready state, and when the data exchange and network communication processing process (P3) between the communication module and the sensor module is executed, the voltage and current are sampled and processed (P1) And the operation processing process (P2) is in a ready state.

The microprocessor has Flash memory and RAM. The sampling process of voltage and current is performed by the sampling mode of direct access memory (DMA). Here, the voltage and current sampling processing process (P1), the calculation processing process (P2), the data exchange between the communication module and the sensor module and the network communication processing process (P3) are respectively started by interrupting the program, thereby realizing a microprocessor The device realizes the processes of P1, P2, and P3.

In the electric energy meter proposed in the third aspect of the present invention, the sensor module can sample the voltage and current signals of a plurality of electrical equipment independent of each other; the microprocessor performs sampling processing (P1, P1', P1"). Here, not only the energy data of one electrical device is measured, but also the voltage and current signals of multiple independent electrical devices are sampled and processed. Therefore, the use efficiency of the energy meter can be improved.

In the electric energy meter proposed in the fourth aspect of the present invention, the sensor module also includes a switching part, which is used to switch electrical equipment that needs to perform voltage and current signal sampling processing; Before the processing process (P3), switch the electrical equipment that needs to perform voltage and current signal sampling processing. Here, when the voltage and current sampling process (P1) is executed on the specified electrical equipment from multiple electrical equipment, the switching part first performs the switching of the electrical equipment to designate the calculation process (P2) or the network communication process ( P3) electrical equipment.

In the energy meter proposed in the fifth aspect of the present invention, the microprocessor adjusts the time interval for sampling the voltage and current signals according to the power cycle.

In the present invention, a microprocessor is used to perform voltage and current signal sampling processing and calculation processing of the sensor module, and the communication module performs data exchange and network communication processing with the sensor module. Therefore, the sampling of the input voltage waveform and the input current waveform is not continuous sampling, but they are sampled at certain intervals, so there may be errors in the sampled data. Here, the time interval for sampling the voltage and current signals is adjusted according to the power cycle to obtain the most suitable sampling interval. Sampling according to this sampling interval can minimize the data error caused by interval sampling.

In the energy meter proposed by the sixth aspect of the present invention, the microprocessor corrects the current value, voltage value, and power value according to the power supply cycle and the sampling processing interval.

Here, in order to suppress the data error caused by interval sampling, the current value, voltage value, and power value are corrected. At this time, the current value, voltage value, and power value are corrected according to the power cycle and sampling interval, which can minimize the data error caused by interval sampling, thereby improving the accuracy of the energy meter.

In the energy meter proposed by the seventh aspect of the present invention, the microprocessor corrects the current value, voltage value, and power value based on the final measured value of the sampled current or voltage. Here, in order to suppress data errors caused by interval sampling, the microprocessor is controlled to correct the current value, voltage value, and power value according to the final measured value of the sampled current or voltage. Therefore, the most appropriate correction value can be obtained, thereby improving the accuracy of the electric energy meter.

In the electric energy meter proposed by the eighth aspect of the present invention, the circuit board of the microprocessor includes a power supply circuit, an analog circuit and a digital circuit, wherein the ground wires of the power supply circuit, the analog circuit and the digital circuit have a common connection point.

Here, for example, the ground point of the power circuit, the ground point of the analog circuit, and the ground point of the digital circuit are connected to the ground point as a common connection point. If each grounding point is connected to a different grounding point, errors due to different grounding points are likely to occur. The power circuit of the circuit board of the microprocessor and the analog and digital circuits have a common connection point. In this way, errors occurring between connection points are suppressed, and the accuracy of the electric energy meter is also improved.

In the electric energy meter proposed by the ninth aspect of the present invention, the amplifier circuit included in the analog circuit is a differential amplifier circuit.

In the energy meter proposed by the tenth aspect of the present invention, the communication module further has a web server, and the measured power parameters can be updated on the web page of the web server.

Here, because the communication module of the electric energy meter has a Web server, the power parameters measured by the electric energy meter can be transmitted through the Internet.

The power monitoring system proposed in the eleventh aspect of the present invention includes: an electric energy meter with a sensor module and a communication module, and a user monitoring device, wherein the user monitoring device also has an electric energy meter management module for displaying and storing information from The data received by the above-mentioned communication module is used to manage the electric energy meter.

In the power monitoring system proposed in the twelfth aspect of the present invention, the energy meter management module can be executed on the user monitoring device, and is transmitted to the user monitoring device by the Web server of the energy meter communication module through the network for execution.

In the power monitoring system proposed in the thirteenth aspect of the present invention, the user monitoring device also includes a memory module, which records the long-term operation of the electric energy meter and the electric parameters transmitted from the electric energy meter to the electric energy meter management module, and can simultaneously pass the table and Graphically display the contents of the memory. And the energy meter management module can be executed on the user monitoring device for a long time, and collects and saves the data transmitted from the Web server of the energy meter communication module.

In the power monitoring system proposed in the fourteenth aspect of the present invention, the energy meter management module can set the start time of data collection, the stop time of data collection and the time interval of data collection on the user monitoring device.

In the power monitoring system proposed in the fifteenth aspect of the present invention, the electric energy meter management module can store the measured value and the current measured time in the memory module of the user monitoring device.

The power monitoring system proposed by the eleventh aspect to the fifteenth aspect of the present invention includes: a power meter with a sensor module and a communication module, and a user monitoring device. Among them, the user monitoring device also has a power meter management module, which can display the data received from the communication module through the network, and can save and calculate the above data. Therefore, the management of any electric energy meter mentioned in the first aspect to the tenth aspect of the present invention is realized through the network.

Description of drawings

In Fig. 1, (a) is an external view of an electric energy meter, and (b) is an enlarged view of a sensor connection part.

Figure 2 is a schematic diagram of the principle of the multi-function electric energy meter.

Fig. 3 is a relational diagram of electrical circuit modules of the multifunctional electric energy meter.

In Fig. 4, (a) is a waveform diagram of a voltage signal and a current signal, and (b) is a diagram of a voltage pulse signal.

Fig. 5 is a diagram of the sampling process of the voltage signal and the current signal.

FIG. 6 is a signal period diagram of a voltage signal.

In Fig. 7, (a) is a voltage pulse signal diagram, (b) is a sampling error diagram of a voltage signal and a current signal, and (c) is an enlarged diagram of a dotted line in (b).

FIG. 8 is a schematic diagram of a power monitoring system.

FIG. 9 is a communication mode diagram of the power monitoring system.

Figure 10 is the screen downloaded from the web server of the multi-function electric energy meter.

Fig. 11 is a display screen of the type of electrical circuit and the PT/CT rate.

Figure 12 is the interface when the accumulated active power/accumulated reactive power is reset.

Figure 13 is the interface when collecting data.

Figure 14 is the configuration IP address interface.

Figure 15 is the web server upload interface.

In the above figure, 1 electric energy meter main shell, 2 channels 1 current transformer CT, 3 channels 1 transformer PT, 4 channels 2 transformers PT, 5RJ-45 interface, 6 channels 2 current transformers CT, 7 channels 2 current transformers CT , 8 network connection line, 9 single-phase two-wire power line, 10 three-phase three-wire power line, 11PT and CT connection part, 12 sensor module, 13 communication module, 14 microprocessor module circuit, 15 memory module circuit, 16 switching power supply module circuit , 17 network interface module circuit, 18 signal processing module circuit, 18a signal processing circuit of circuit 1, 18b signal processing circuit of circuit 2, 18c switching circuit of circuit 1 and circuit 2, 19 voltage signal, 20 current signal, 21 voltage pulse Signal, 22 icon for reading circuit type and PT/CT rate, 23 icon for setting circuit type and PT/CT rate, 24 icon for reset active/reactive work, 25 icon display area, 26 icon for displaying current channel circuit type, 27 Channel selection icon, 28 Current time, 29 Current value, 30 Cumulative value, 31 Multi-function electric energy meter number selection icon, 32 Multi-functional electric energy meter IP address input area, 33 Time setting area, 34 Save file path setting Area, 35 start and stop buttons, 36 status bar, 60 microprocessor, 80 user monitoring device, 100 electric energy meter, 200 power monitoring system.

Detailed ways

In the following, the electric energy meter and the power monitoring system related to the present invention will be described with reference to the drawings and embodiments.

FIG. 1 is an external view of an electric energy meter 100 capable of simultaneously measuring a single-phase two-wire circuit and a three-phase three-wire circuit. A plurality of connection points 11 are provided on the main body casing 1 of the electric energy meter. Here, the current sensor 2 and the transformer 3 of the single-phase two-wire electrical circuit and the current sensors 6, 7 and the transformer 4 of the single-phase three-wire electrical circuit are respectively connected to the connection part 11 by wires.

As shown in Figure 1(a), single-phase two-wire and single-phase three-wire are mutually independent channels. The user monitoring device can set the circuit type of electrical equipment according to needs, such as single-phase two-wire, single-phase three-wire and three-phase three-wire. When the power line voltage 9, 10 is less than 240V, the transformers 3, 4 in Fig. 1(a) can be omitted. The current transformers 2, 6, and 7 are clamp transformers as shown in Fig. 1(b). The user does not need to disconnect the insulation layer of the power line, but only needs to clamp the clamp transformer to the power line.

In addition, the energy meter can measure any channel independently. At this time, it is not necessary to input the signals of the channels that do not need to be measured. Furthermore, the energy meter does not require an additional power supply, and the voltage input of channel 1 or channel 2 can also be used as the input of the power supply module of the energy meter.

FIG. 2 is a system block diagram of the electric energy meter 100 . As shown in FIG. 2 , the electric energy meter 100 is mainly composed of two parts: a sensor module STIM 12 and a communication module NCAP 13 .

The sensor module STIM 12 includes: current transformers CT2, 6, 7, transformers PT 3, 4, electronic database TEDS 12a, data exchange register 12b, electrical parameter calculator 12c, analog signal conditioner 12d, and is responsible for the electrical equipment Pick up, sample and calculate the electrical parameters, and be responsible for the management of the energy meter. The electrical signal (current and voltage) of the electrical equipment is obtained by the sensor through the current transformer CT 2, 6, 7 and the built-in transformer to obtain the AC weak signal.

The input AC weak signal is converted into a 0-5V DC signal by the analog signal conditioner 12d. The electrical parameter calculator 12c samples the DC signal of 0-5V, and calculates voltage effective value, current effective value, power factor, frequency, useful power, reactive power, useful work and reactive work according to the sampled voltage instantaneous value and current instantaneous value . The sensor electronic database TEDS 12a completes the management of the working status of the electric energy meter, such as configuring the IP address of the electric energy meter, setting the circuit type of the electric equipment currently measured by the electric energy meter, the ratio of the transformer and current transformer used, and the power consumption of the electric energy meter. management etc.

The communication module NCAP 13 has a data exchange register 13a, a TCP/IP protocol processor 13b, a web server 13c, a TCP/IP protocol stack 13d, and a network controller 13e, and is responsible for data exchange between the energy meter and the client, and network communication.

The network controller 13e realizes the physical interface between the energy meter and Ethernet (Ethernet), and receives and sends network data. The TCP/IP protocol stack 13d implements Address Resolution Protocol ARP, Internet Protocol IP, User Datagram Protocol UDP, Network Control Message Protocol ICMP, Transmission Control Protocol TCP and Hypertext Transfer Protocol HTTP, and analyzes and packages network data.

When receiving data, the TCP/IP protocol processor 13b reads the data packet from the receiving buffer of the network controller 13e, and parses the data packet through the link layer, the network layer, the transport layer and the application layer; when sending data, the TCP The /IP protocol processor 13b adds a header to the data to be sent through the reverse process, packs the characters and data into a sent data packet, sends it to the sending buffer of the network controller 13e, and starts the sending command to complete sending. The webpage server 13c is responsible for the management of the webpage and saving the required text of the webpage on the storage device, and the storage device refers to a FLASH memory or the like.

Here, the sensor module 12 and the communication module 13 share a microprocessor 60 . The microprocessor 60 performs data calculation processing (p2), data exchange processing between the communication module and the sensor module, and network communication processing (p3).

FIG. 3 is a hardware circuit of the sensor module of the electric energy meter 100 . As shown in FIG. 3 , the sensor module of the electric energy meter 100 mainly consists of the following parts: a switching power supply module circuit 16 , a memory module circuit 15 , a CPU module circuit 14 , a network interface module circuit 17 and a signal sampling processing module circuit 18 .

Here, the switching power supply module circuit 16, the CPU module circuit 14 and the signal sampling processing module circuit 18 are grounded through a common connection point. Also, the amplifier circuit of the signal sampling processing module circuit 18 is a differential amplifier circuit.

In addition, the switching power supply module circuit 16, the CPU module circuit 14, and the signal sampling processing module circuit 18 use power and ground for analog circuits and power and ground for digital circuits that do not affect each other. The power supply for analog circuits and the power supply for digital circuits are connected using a common connection point. Moreover, the ground used for the analog circuit and the ground used for the digital circuit are also connected using a shared connection point. In other words, a ground connection point is used. Thereby, the independence of the analog circuit and the digital circuit is enhanced, and unnecessary garbled codes can be reduced from entering into other electrical circuits, thereby realizing the stability of the signal processing circuit.

In addition, the circuit for amplifying the input signal provided at the input end of the signal sampling processing part is a differential amplifier circuit.

As shown in Figure 2, the 0~30mA AC current signal obtained by the external current sensors 2, 6, and 7 and the AC weak voltage signal obtained by the built-in transformer are converted into 0V~5V after 12 days of analog signal conditioning Weak signal. The switching circuit 18c controls the I/O port of the CPU module circuit 14 to switch between the circuit 118a or the circuit 218b according to the command of the microprocessor 60,

The microprocessor 60 sets the time interval for sampling processing and A/D conversion processing of channel 1 and channel 2, and performs calculation processing on the sampled data, and calculates the electrical parameter value. The CPU module circuit 14 implements the sampling and calculation of electrical parameters and the TCP/IP protocol stack. Memory module circuit 15 is made up of the FLASH memory of 512K and the RAM memory of 32K, and FLASH and RAM memory are used for storing the web page and temporary data of English, Chinese two languages respectively. The network interface module circuit 17 completes the physical interface between the electric energy meter and the Internet, and realizes the information exchange between the electric energy meter 100 and the outside world. The switching power supply module takes the voltage of channel 1 as input, and generates a constant current of 5V through circuits such as shaping and filtering as the power supply of the energy meter.

Figure 4(a) shows the waveforms of the current signals obtained by the current transformers CT 2, 6, 7 and the waveforms of the voltage signals obtained by the transformers PT3, 4. In the figure, 19 represents a voltage signal, and 20 represents a current signal. Figure 4(b) shows the pulse signal 21 generated after the voltage signal is passed through the arithmetic amplifier circuit and pulse shaped. The pulse signal is sent to the external interrupt pin of the microprocessor, and the microprocessor generates an interrupt at the falling edge of the signal level, and activates the sampling process (P1) in the interrupt program. After the interrupt reset initialization, the microprocessor 60 performs data calculation processing (P2), and the communication module and the sensor module perform data exchange and network communication processing (P3).

In FIG. 4 , the synchronous pulse signal 21 generated by the voltage signal 19 is used as the signal source of the counter of the microprocessor 60 . After the reset initialization, the three processes P1, P2 and P3 of the IP energy meter are all in the ready state. When the first cycle of the voltage signal arrives, that is, at time _t0 , the external interrupt pin of the microprocessor has a level jump and an interrupt is generated. In the interrupt program, set the sampling flag as 1, and activate the voltage and current signal sampling process (P1). In the first cycle of the voltage signal 19, the microprocessor 60 samples the voltage signal 19 and the current signal 20 of the channel 118a, and saves the sampled values into the RAM memory. When the sampling process (P1) is in the execution state, the processes P2 and P3 are in the ready state. At time _t1 , the level of the external interrupt pin of the microprocessor 60 jumps again to generate an interrupt, and the sampling flag becomes 0 in the interrupt program, and the electrical parameter calculation flag is set to 1 at the same time, the process P2 is in the execution state, and the process P1 , P3 is in the ready state. The microprocessor 60 calculates eight electric parameter values such as voltage effective value and current effective value according to the sampled voltage signal and instantaneous value of current signal. After the calculation of electrical parameters is completed, the cumulative value of useful power and useless power is stored in the internal data Flash memory of the microprocessor.

At time _t2 , when the electrical parameter calculation flag is set to 0, in the following N-2 voltage cycles, the voltage and current signal sampling process (P1) and the electrical parameter calculation and saving process (P2) are both in the ready state, and the network communication process (P3) is in the execution state, and the microprocessor 60 responds to the request from the client to perform communication processing. Time t ₂ is an uncertain value, according to the voltage signal frequency and the size of the calculation, the calculation time of electrical parameters is within 1 or 2 cycles. After the network communication of N-2 cycles ends, the microprocessor 60 switches to another channel to do the same processing. In this repeated cycle, a microprocessor is used to divide by time to realize the three processes of voltage and current signal sampling (P1), calculation and storage of electrical parameters (P2), and network communication (P3).

Figure 5 shows the voltage and current signal sampling (P1) process. Here, 19' is a voltage signal, and 20' is a current signal. After setting the sampling flag as 1 in the external interrupt program, start the timer of the microprocessor, the timing time is ΔT, and the mode is continuous loading mode. When the timing time arrives, a timer interrupt is generated, and the DMA sampling of the microprocessor is started in the timer interrupt program, and the voltage signal and the current signal are continuously sampled. After sampling, save the sampling result to the specified memory space. Then wait for the next timer interrupt, and start the next DMA to sample when the next timer interrupt occurs, until the sampling flag is cleared. Here, the method of correcting the sampling leakage of the voltage signal and the current signal is described by using the correction of the sampling leakage of the current signal.

Taking voltage as an example, the correction method for compensating the sampling error of the voltage signal and the current signal will be described below.

Usually, the actual value u of the continuous voltage signal is calculated according to the following formula (1):

$\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="T\; u"\; filenames="C20061002739600171.png,C20061002739600211.png"\; state="\{\{state\}\}">T</figure-callout></span><figure-callout\; id="2"\; label="T\; u"\; filenames="C20061002739600171.png,C20061002739600211.png"\; state="\{\{state\}\}">\; </figure-callout>}}{\mathrm{<span\; class="notranslate">\; </span>}}^{}{\mathrm{<span\; class="notranslate">u</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; dt</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

After discretization, the effective value of the voltage (the number of samples in a 2π period is N) is calculated according to the following formula (2):

$\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; =</span>\sqrt{\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; N</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

In formula (2), the signal period of the voltage signal u is set to be evenly divided into N sampling periods as shown in FIG. 6 . However, in the actual use environment, the input signal is not necessarily very uniform, there will be deviations, and the signal processing circuit is unstable, resulting in slight changes in the signal period, so it is difficult to ensure that the signal period T is evenly divided into N sampling periods. Therefore, it is easy to make an error when calculated by calculation formula (2). This is the sampling error shown in Figure 7. Fig. 7(a) shows a pulse signal of a voltage signal. 19a in FIG. 7(b) represents a voltage signal, and 19b represents a current signal. The hatched portion in FIG. 7(c) is an enlarged view of the dotted line portion in FIG. 7(b). In Fig. 7(b), the signal periods of voltage and current are not evenly divided by the sampling period TS. That is, since the interval between t1 and t2 is shorter than the sampling period TS, a sampling error occurs. The slanted parts A and B in FIG. 7(c) respectively represent the sampling leakage of the voltage signal and the sampling error of the current signal.

Here, by calculating the effective value of the current signal through formula (3), the sampling error of the current signal can be corrected, so as to ensure the accuracy of sampling.

$\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="T\; i"\; filenames="C20061002739600171.png,C20061002739600211.png"\; state="\{\{state\}\}">T</figure-callout></span><figure-callout\; id="2"\; label="T\; i"\; filenames="C20061002739600171.png,C20061002739600211.png"\; state="\{\{state\}\}">\; </figure-callout>}}{\mathrm{<span\; class="notranslate">\; </span>}}^{}{\mathrm{<span\; class="notranslate">i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; dt</span>}}$

$<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; [</span>\frac{\mathrm{<span\; class="notranslate">\; Ts</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="o"\; filenames="C20061002739600171.png,C20061002739600211.png"\; state="\{\{state\}\}">o</figure-callout></span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="i"\; filenames="C20061002739600211.png,C20061002739600221.png"\; state="\{\{state\}\}">i</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; Ts</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="i"\; filenames="C20061002739600211.png,C20061002739600221.png"\; state="\{\{state\}\}">i</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="i"\; filenames="C20061002739600171.png,C20061002739600211.png"\; state="\{\{state\}\}">i</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; Ts</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="t"\; filenames="C20061002739600211.png,C20061002739600221.png"\; state="\{\{state\}\}">t</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}$

$<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; Ts</span>}<span\; class="notranslate">\; (</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; Ts</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; Ts</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="0"\; label="i"\; filenames="C20061002739600211.png,C20061002739600281.png"\; state="\{\{state\}\}">i</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="t"\; filenames="C20061002739600211.png,C20061002739600221.png"\; state="\{\{state\}\}">t</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

从而从计算式(3)得到下面的计算式(4)。Also, as can be seen from FIG. 7, i ₀ =i _N . When the interval between t2 and t1 is small, it can be assumed that

The following calculation formula (4) is thus obtained from the calculation formula (3).

$\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; Ts</span>}<span\; class="notranslate">\; (</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ]</span>}$

$<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; Ts</span>}<span\; class="notranslate">\; *</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; Ts</span>}<span\; class="notranslate">\; (</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ]</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

In formula (4), (t ₂ -t ₁ ) is an unknown number, which can be calculated using T, Ts, and N. As another method, in order to calculate the interval between t2 and t1, the calculated value of the binary counter can be read when an external interrupt occurs (t2). The time interval between t2 and t1 is calculated according to the increase of the calculated value of the binary counter. Theoretically speaking, a relatively correct value of the current signal can be obtained according to the above correction.

The power monitoring system will be described below. The power monitoring system 200 shown in FIG. 8 includes a power meter 100 and a user monitoring device 80 . The energy meter 100 has the sensor module 12 and the communication module 13 in FIG. 2. The user monitoring device 80 has the energy meter management module for displaying and storing the data received from the communication module 13 through the network, and managing the energy meter.

FIG. 9 shows the data exchange process between the user monitoring device 80 of the user and the web server 13c of the energy meter 100 . First, the user monitoring device 80 sends a communication start request to the web server 13c of the electric energy meter 100, and the web server 13c immediately responds to the user monitoring device 80 after receiving the communication start request. Afterwards, the user monitoring device 80 sends a request for data transmission again, and the web server 13c immediately transmits the data to the user monitoring device 80 after receiving the data transmission request and downloads it. Afterwards, an interface as shown in FIG. 10 appears in the user monitoring device 80 .

On the top of the web page are three labels about the energy meter configuration: read circuit type and PT/CT rate 22, read circuit type and PT/CT rate 23, reset active/reactive work 24.

When the user clicks on the “read circuit type and PT/CT rate” 22 label on the user monitoring device 80 interface, the circuit type and PT/CT rate of the two channels of the electric energy meter are displayed in the label display area 25 . Click on the "set circuit type and PT/CT rate" 23 label, the label display area 25 in Figure 11 displays the interface as shown in Figure 10, you can set the circuit type and PT/CT rate of the two channels of the electric energy meter respectively, through the drop-down menu The circuit type can be selected among single-phase two-wire, single-phase three-wire and three-phase three-wire. Click the "accumulated useful work/accumulated reactive work reset" 24 label, and the label display area 25 in Figure 12 displays the interface shown in Figure 10, and the accumulated values of the two channels can be cleared through different combinations. Channel selection 27 selects between two channels of the electric energy meter. When a certain channel is selected, the current value 29 and the accumulated value 30 are displayed as the electrical parameter values of the channel. In order to improve the performance of the energy meter, the data exchange between the above client and the energy meter is through the UDP protocol. The client requests data transmission from the energy meter 100 through the UDP protocol every second to update the data displayed on the web page.

The energy meter management module can use "data collection software" (as shown in Figure 13) and "IP configuration and web page upload software" (as shown in Figure 14 and Figure 15).

"Data collection software" is used to collect data collected by electric energy meters on the LAN for a long time. The software can collect the electricity consumption of electrical equipment within a set period of time, and save the data as a file in CSV (electronic form) format, which is convenient for users to maintain the equipment. As the interface shown in Figure 13, this software can collect the data of 8 energy meters on the local area network at the same time, and input the IP address of the energy meters in the IP address input area 32. In the time setting area 33, you can set the start time, end time and time interval of each data collection. You can choose the directory to save the file at will. The data of each energy meter is saved as a file, and the file name is a combination of the start time and the IP address of the energy meter. Every time a piece of data needs to be collected, the client sends a UDP packet to the energy meter to request data, and the energy meter sends the latest electrical parameter value to the client through the UDP protocol.

As shown in FIG. 14 , the "IP configuration and webpage upload software" is used to configure the IP address of any specified electric energy meter 100 on the LAN. The client communicates with the energy meter 100 by setting the IP address of the energy meter 100 using the IP address.

The energy meter 100 as the communication terminal obtains the data of the electronic database TEDS (Transducer Electronic Database) of the sensor module 12 based on the IEEE1451 standard, and saves it in the TEDS format. The TEDS format data received by the energy meter 100 can be viewed by the user on the user monitoring device 80 through network communication.

For example, in the web server 13 c of the electric energy meter 100 , data in HTML format is generated from data in TEDS format, and the data can be browsed on the user monitoring device 80 through HTTP communication. At this time, every time data in the TEDS format is updated, the energy meter 100 also updates and generates new data in the HTML format, and stores the data in the memory module 15 . The user monitoring device 80 sends a browsing request to the web server 13c of the electric energy meter 100 to update the data in the user monitoring device 80 .

In addition, the data in the TEDS format of the web server 13 c of the electric energy meter 100 can also be displayed in real time through the JAVA™ interface. The user monitoring device 80 downloads and executes the interface, so that data can be obtained from the web server 13c of the electric energy meter 100 through the user monitoring device 80 in real time and can be browsed.

Compared with the prior art, the present invention has the following effects:

The energy meter proposed in the first aspect of the present invention can use a microprocessor to perform sampling and calculation processing of voltage and current in the sensor module, as well as data exchange and network communication processing with the sensor module in the communication module. Therefore, the overall cost of the multifunctional electric energy meter can be reduced.

The energy meter proposed in the second aspect of the present invention can realize the processing of P1, P2, and P3 through a microprocessor: the sampling processing of voltage and current values P1, the arithmetic processing of data P2, the data of the communication module and the sensor module Switching and network communication processing P3 are activated by their respective interrupt routines.

The electric energy meter proposed in the third aspect of the present invention not only measures the power value of one electrical device, but also samples the voltage and current of multiple independent electrical devices, which can improve the efficiency of the electric energy meter.

The electric energy meter proposed in the fourth aspect of the present invention is to execute the sampling process P1 of the voltage and current value of the specified electrical equipment among a plurality of electrical equipment, first switch the electrical equipment through the switching module, and execute after the sampling Electrical equipment for operation processing P2 or network communication processing P3.

The electric energy meter proposed in the fifth aspect of the present invention adjusts the sampling processing time interval according to the power supply cycle, calculates the optimal time interval, and executes sampling processing according to the interval, so that the sampling error can be reduced to a minimum.

The energy meter proposed in the sixth aspect of the present invention is to correct the current value, voltage value or power value according to the power supply cycle and the sampling interval, so that the error of the sampling value can be reduced to a minimum, and the multifunctional energy meter can be improved. the accuracy.

The electric energy meter proposed by the seventh aspect of the present invention corrects the current value, the voltage value or the power value based on the final measured value of the sampled current or voltage. Therefore, the optimum correction value can be obtained, and the accuracy of the multifunctional electric energy meter can be improved.

In the electric energy meter proposed in the eighth aspect of the present invention, the power supply circuit, the analog circuit and the digital circuit have a common connection point, and the occurrence of errors between the connection points can be suppressed, thereby improving the accuracy of the multifunctional electric energy meter.

In the watt-hour meter proposed by claim 9 of the present invention, the amplifier circuit of the analog circuit is a differential amplifier circuit.

The electric energy meter proposed by the tenth aspect of the present invention is that a web server is further configured on the multifunctional electric energy meter, and the power parameters measured by the electric energy meter can be transmitted through the network.

The power monitoring system proposed in the 11th to 15th aspects of the present invention includes a power meter with a sensor module and a communication module and a user monitoring device, wherein the user monitoring device also has a power meter management module for displaying and storing data through the network. The data received from the communication module is used to manage the electric energy meter. Therefore, any one of the functions proposed in the first to tenth aspects of the present invention can be managed through the network.

Claims (8)

1. An electric energy meter, comprising:

the sensor module is used for sampling voltage and current signals of the electrical equipment and performing calculation processing on a current value, a voltage value and a power value by using a sampled measured value;

the communication module is used for exchanging data with the sensor module and carrying out network communication processing through a TCP/IP protocol stack; wherein,

the sampling and operation processing of the voltage and the current performed at the sensor module and the data exchange and network communication processing performed at the communication module and the sensor module are controlled by a microprocessor,

the microprocessor adjusts the time interval for sampling the voltage and current signals according to the power supply period, and corrects the current value, the voltage value and the power value according to the power supply period and the sampling processing interval; and the microprocessor corrects the current value, the voltage value and the power value according to the final measurement value of the sampled current or voltage.

2. The electric energy meter of claim 1, wherein: the microprocessor is used for carrying out a voltage and current sampling processing process P1, and the operation processing process P2 and the data exchange and network communication processing process P3 of the communication module and the sensor module are in a ready state; when the operation processing process P2 is executed, the voltage and current sampling processing process P1 and the data exchange and network communication processing process P3 of the communication module and the sensor module are in a ready state; when the data exchange and network communication processing process P3 of the communication module and the sensor module is executed, the voltage and current sampling processing process P1 and the operation processing process P2 are in a ready state.

3. The electric energy meter of claim 2, wherein: the sensor module can sample and process voltage and current signals of a plurality of mutually independent electrical devices;

the microprocessor performs time-sharing sampling processing on P1, P1 'and P1' according to time difference, and the sensor module comprises a switching module which is used for switching electrical equipment needing voltage and current signal sampling processing; the microprocessor switches the electric equipment needing voltage and current signal sampling processing before the operation processing process P2 or the data exchange and network communication processing process P3 between the communication module and the sensor module.

4. An electric energy meter according to claim 1, 2 or 3, characterized in that: the circuit board of the microprocessor comprises a power supply circuit, an analog circuit and a digital circuit, wherein the power supply circuit, the analog circuit and the digital circuit have a common connection point; the analog circuit comprises an amplifier circuit which is a differential amplifier circuit.

5. The electric energy meter of claim 1, wherein: the communication module is also provided with a Web server, and the measured power parameters can be updated on a Web page of the Web server.

6. A power monitoring system including the electrical energy meter of claim 1, comprising: an electric energy meter having a sensor module and a communication module, and a user monitoring device, wherein,

the user monitoring device is provided with an electric energy meter management module which is used for displaying and storing data received from the communication module through a network and managing the electric energy meter.

7. The power monitoring system of claim 6, wherein: the electric energy meter management module can be executed on the user monitoring device for a long time and collects data transmitted from the Web server of the electric energy meter communication module, and the user monitoring device is provided with a memory module and can store the measured value and the current measuring time on the memory module.

8. The power monitoring system of claim 7, wherein: the memory module records the long-term operation condition of the electric energy meter and the electric parameters transmitted from the electric energy meter to the electric energy meter management module, and simultaneously displays the memorized contents in a form and graph mode; the electric energy meter management module can set the data collection starting time, the data collection stopping time and the data collection time interval on the user monitoring device.

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