A device for online monitoring of power quality

Abstract

The present invention discloses an online monitoring device for power quality, wherein M analog boards are used to collect electrical signals from a power grid, and the collected electrical signals are converted into digital signals and then sent to a backplane; N switch boards are used to collect binary input signals, and the collected binary input signals are sent to a backplane; a monitoring board is used to obtain digital signals and binary input signals from the backplane, and analyze and calculate the digital signals and binary input signals to obtain power quality parameters and recording start parameters, and start recording according to the recording start parameters and send the power quality parameters to the backplane; a display board is used to obtain power quality parameters from the backplane and display the power quality parameters. The present invention has multiple monitoring channels, can monitor some long-term power quality parameters, and has the functions of power quality monitoring and fault recording, thereby improving the reliability of power quality monitoring and reducing the manufacturing cost of the equipment.

Description

Technical Field

[0001] The invention relates to the technical field of power electronics, and in particular to an online monitoring device for power quality. Background Art

[0002] Electricity is one of the products with the widest range of uses, the highest use value and the largest usage in modern society. With the development of modern science and technology, the structure of power loads in modern power systems has undergone major changes. The rapid development of loads such as semiconductor rectifiers, thyristor voltage regulators and frequency converters, steelmaking arc furnaces, electrified railways and household appliances has caused the voltage waveform of the power grid to be distorted due to its nonlinear, impact and unbalanced power consumption characteristics, causing voltage fluctuations and flickers, three-phase imbalance, and even system frequency fluctuations, causing serious interference or pollution to the power quality of the power supply. The power grid is facing more and more power quality problems, so the monitoring, analysis and management of power quality have become increasingly important.

[0003] Power quality monitoring devices and fault recorders provide a scientific basis for power system staff to monitor power quality, analyze, and handle power system faults. At present, there are many power quality monitoring equipment or instruments on the market, and the commonly used ones are portable power quality analyzers and fixed power quality online monitoring devices. Among them, portable power quality analyzers have few monitoring channels and are inconvenient to monitor some long-term power quality indicators. Fixed power quality online monitoring devices can only measure power quality indicators and do not support recording functions. The recording function analyzes the voltage and current waveforms before and after the fault when a fault occurs in the power system, which is convenient for fault analysis and quick fault handling, and is also very necessary. The existing independent power quality monitoring devices and fault recording devices use independent power supplies and data storage devices, etc., and the manufacturing cost is relatively high. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an online power quality monitoring device with multiple monitoring channels, which can monitor some long-term power quality parameters and has the functions of power quality monitoring and fault recording, thereby improving the reliability of power quality monitoring and reducing the equipment manufacturing cost.

[0005] In order to solve the above technical problems, the present invention provides an online monitoring device for power quality, comprising M analog quantity boards, N switch quantity boards, a monitoring board, a backboard and a display board, wherein the M analog quantity boards, N switch quantity boards, the monitoring board and the display board are all connected to the backboard;

[0006] The M analog panels are used to collect electrical signals from the power grid, and convert the collected electrical signals into digital signals and then send them to the backplane;

[0007] The N switch quantity boards are used to collect binary input quantity signals and send the collected binary input quantity signals to the backplane;

[0008] The monitoring board is used to obtain the digital signal and the binary input signal from the backboard, analyze and calculate the digital signal and the binary input signal to obtain power quality parameters and recording start parameters, and start recording according to the recording start parameters and send the power quality parameters to the backboard;

[0009] The display panel is used to obtain the power quality parameters from the back panel and display the power quality parameters.

[0010] Furthermore, the analog measurement board includes a signal acquisition module for acquiring electrical signals of the power grid, an analog signal processing module, an AD acquisition module and a programmable logic device;

[0011] The signal acquisition module is connected to the analog signal processing module, the analog signal processing module is connected to the AD acquisition module, the AD acquisition module is connected to the programmable logic device, and the programmable logic device is connected to a backplane.

[0012] Furthermore, the programmable logic device adopts FPGA.

[0013] Furthermore, the signal acquisition module includes four voltage transformers for acquiring voltage signals of the power grid and four current transformers for acquiring current signals of the power grid.

[0014] Further, the monitoring board includes a first control processing module for acquiring the digital signal and the binary input signal from the backplane, a second control processing module for analyzing and calculating the digital signal and the binary input signal, a first storage module and a second storage module;

[0015] The first control processing module is connected to the first storage module, the second control processing module is connected to the second storage module, and the first control processing module is in communication connection with the second control processing module.

[0016] Furthermore, the monitoring board also includes a USB interface module, an Ethernet interface module and an RS485 interface module connected to external communication, and the USB interface module, the Ethernet interface module and the RS485 interface module are all connected to the second control processing module.

[0017] Furthermore, the first control processing module is an FPGA, the second control processing module is an ARM processor, the first storage module is a dual-port RAM, and the second storage module is an SD CARD.

[0018] Furthermore, the monitoring board further comprises a display interface module, the display interface module is connected to the second control processing module, and the display interface module is also connected to the backplane;

[0019] The display panel includes a display connected to a back panel.

[0020] Further, the display panel includes an LED module, and the LED module is connected to the back panel;

[0021] The display panel also includes a USB interface or an RS485 interface, and the USB interface or the RS485 interface is connected to the back panel.

[0022] Furthermore, the switch quantity board includes a first connection terminal, a second connection terminal, an input optocoupler, an output optocoupler, a relay drive module, a relay and a programmable logic device;

[0023] The first connection terminal is connected to the open-input optocoupler, the open-input optocoupler is connected to the programmable logic device, the programmable logic device is connected to the backplane, the programmable logic device is also connected to the open-output optocoupler, the open-output optocoupler is connected to the relay drive module, the relay drive module is connected to the relay, and the relay is connected to the second connection terminal.

[0024] The invention provides an online power quality monitoring device, wherein M analog quantity boards collect electric signals of a power grid, convert the collected electric signals into digital signals and then send them to a backboard; N switch quantity boards collect binary input signals and send the collected binary input signals to the backboard, and the multiple monitoring channels formed by the M analog quantity boards and the N switch quantity boards can monitor some long-term power quality parameters, thereby improving the reliability of power quality monitoring; the monitoring board obtains digital signals and binary input signals from the backboard, analyzes and calculates the digital signals and the binary input signals to obtain power quality parameters and recording start parameters, and starts recording according to the recording start parameters and sends the power quality parameters to the backboard; the display board obtains power quality parameters from the backboard and displays the power quality parameters, and simultaneously has the functions of power quality monitoring and fault recording, thereby improving the reliability of power quality monitoring and reducing the manufacturing cost of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the power quality online monitoring device provided by the present invention;

[0026] Figure 2 It is a structural schematic diagram of an embodiment of an analog quantity board of the online power quality monitoring device provided by the present invention;

[0027] Figure 3It is a structural schematic diagram of an embodiment of a monitoring board of the online power quality monitoring device provided by the present invention;

[0028] Figure 4 It is a structural schematic diagram of an embodiment of a switch quantity board of the online power quality monitoring device provided by the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] See also Figure 1 , is a structural schematic diagram of the online power quality monitoring device provided by the present invention.

[0031] The present invention provides an online monitoring device for power quality, comprising M analog quantity boards 1, N switch quantity boards 2, a monitoring board 3, a backboard 4 and a display board 5, wherein the M analog quantity boards 1, the N switch quantity boards 2, the monitoring board 3 and the display board 5 are all connected to the backboard 4;

[0032] The M analog boards 1 are used to collect electrical signals from the power grid, convert the collected electrical signals into digital signals and send them to the backplane 4;

[0033] N switch quantity boards 2 are used to collect binary input quantity signals and send the collected binary input quantity signals to the backplane 4;

[0034] The monitoring board 3 is used to obtain digital signals and binary input signals from the backboard 4, analyze and calculate the digital signals and binary input signals to obtain power quality parameters and recording start parameters, and start recording according to the recording start parameters and send the power quality parameters to the backboard 4;

[0035] The display panel 5 is used to obtain power quality parameters from the back panel 4 and display the power quality parameters.

[0036] In the specific implementation, M analog boards 1 collect electrical signals from the power grid, convert the collected electrical signals into digital signals and send them to the backboard 4; N switch boards 2 collect binary input signals and send the collected binary input signals to the backboard 4. The M analog boards 1 and the N switch boards 2 constitute multiple monitoring channels, which solves the problem of few detection channels, can monitor some long-term power quality parameters, and improve the reliability of power quality monitoring; the monitoring board 3 obtains digital signals and binary input signals from the backboard 4, analyzes and calculates the digital signals and binary input signals to obtain power quality parameters and recording start parameters, and starts recording according to the recording start parameters and sends the power quality parameters to the backboard 4; the display board 5 obtains power quality parameters from the backboard 4 and displays the power quality parameters. It also has the functions of power quality monitoring and fault recording. When a system fault occurs, it can automatically and accurately record the changes of various electrical quantities before and after the fault, improve the reliability of power quality monitoring, and reduce the equipment manufacturing cost.

[0037] It should be noted that the power quality parameters include but are not limited to voltage, frequency, three-phase unbalance, voltage fluctuation, flicker, harmonics and harmonic power. Among them, the backplane 4 provides a channel for communication between each socket panel: switch quantity board 2, analog quantity board 1 and monitoring board 3, and is the transportation hub of the entire system. Here, M is equal to 3 and N is equal to 2 for example. The data bus width of the backplane 4 can be 16 bits and the address bus can be 8 bits. Figure 1 As shown, fixed addressing addresses are assigned to two switch boards 2, three analog boards 1 and monitoring board 3. The address of monitoring board 3 is 000, the order of three analog boards 1 is 001, 010 and 011, and the address of two switch boards 2 is 100 and 101. When the upper 3 bits of the address bus of the backplane 4 controlled by monitoring board 3 are consistent with the fixed addressing address of a certain socket panel, this socket panel is selected. For example, when the upper 3 bits of the address bus of the backplane 4 controlled by monitoring board 3 are 010, the analog board 1 with the addressing address of 010 is selected. At the same time, the lower 5 bits of the address are used for data addressing to complete board selection and communication between each socket panel.

[0038] See also Figure 2 , is a schematic diagram of the structure of an embodiment of an analog quantity board of the online power quality monitoring device provided by the present invention. Figure 2 As shown, the analog measurement board 1 includes a signal acquisition module 11 for acquiring electrical signals of a power grid, an analog signal processing module 12, an AD acquisition module 13 and a programmable logic device 14;

[0039] The signal acquisition module 11 is connected to the analog signal processing module 12 , the analog signal processing module 12 is connected to the AD acquisition module 13 , the AD acquisition module 13 is connected to the programmable logic device 14 , and the programmable logic device 14 is connected to the backplane 4 .

[0040] Among them, the working process of the analog quantity board 1 is as follows: the signal acquisition module 11 collects the electrical signal of the power grid, and sends the collected electrical signal to the analog signal processing module 12 for processing, the analog signal processing module 12 sends the processed electrical signal to the AD acquisition module 13, the programmable logic device 14 obtains the sampling synchronization pulse sent by the monitoring board 3 through the backplane 4, and sends it to the AD acquisition module 13 for synchronous sampling, after the AD acquisition module 13 completes the sampling, it sends a sampling completion signal to the programmable logic device 14, after receiving the sampling completion signal, the programmable logic device 14 reads the sampled digital signal and stores it, and the monitoring board 3 reads the digital signal through the backplane 4.

[0041] Furthermore, the programmable logic device 14 adopts FPGA.

[0042] Furthermore, the signal acquisition module 11 includes four voltage transformers for acquiring voltage signals of the power grid and four current transformers for acquiring current signals of the power grid.

[0043] It should be noted that the four voltage transformers and the four current transformers respectively collect the A, B, C three-phase and zero-sequence voltage of the measured voltage, and the A, B, C three-phase and zero-sequence current of the measured current. The measured voltage and the measured current are converted into small voltage signals by the voltage transformer and the current transformer respectively, and then processed by the analog signal processing module 12 and sent to the AD acquisition module 13. The FPGA obtains the sampling synchronization pulse sent by the monitoring board 3 through the backplane 4, filters out the burrs through the D trigger, and sends it to the AD acquisition module 13 for synchronous sampling. When the FPGA detects that the state of the AD acquisition module 13 has turned to idle, the digital signal after sampling and processing is immediately read out from the AD acquisition module 13, stored in its own dual-port RAM, and a read signal is sent to the monitoring board 3 through the backplane 4 to remind the monitoring board 3 to read the digital signal in time.

[0044] The device uses the internationally advanced embedded hardware structure FPGA for sampling and signal processing, which has the characteristics of strong analysis ability and fast operation speed. FPGA is a new low-power chip, and its hardware redundancy design and other technical solutions make the device run more stable and reliable.

[0045] See also Figure 3 , is a schematic diagram of the structure of an embodiment of a monitoring board of the online power quality monitoring device provided by the present invention. Figure 3As shown, the monitoring board 3 includes a first control processing module 31 for acquiring digital signals and binary input signals from the backplane 4, a second control processing module 32 for analyzing and calculating the digital signals and binary input signals, a first storage module 33 and a second storage module 34;

[0046] The first control processing module 31 is connected to the first storage module 33 , the second control processing module 32 is connected to the second storage module 34 , and the first control processing module 31 is in communication connection with the second control processing module 32 .

[0047] It should be noted that: the first control processing module 31 obtains the digital signal and the binary input signal from the backboard 4, and stores it in the first storage module 33, the second control processing module 32 reads the digital signal and the binary input signal stored in the first storage module 33, and analyzes and calculates the digital signal and the binary input signal to obtain the power quality parameters and the recording start parameters, and starts the recording according to the recording start parameters, and stores the recording data and the power quality parameters in the second storage module 34.

[0048] Furthermore, the monitoring board 3 also includes a USB interface module 36 , an Ethernet interface module 35 and an RS485 interface module 38 connected to external communication, and the USB interface module 36 , the Ethernet interface module 35 and the RS485 interface module 38 are all connected to the second control processing module 32 .

[0049] It should be noted that the Ethernet interface module 35 includes two Ethernet control chips LAN9221 and two RJ45 network ports for communicating with the external background. The USB interface module 36 includes four USB interfaces that can be used to connect to the touch screen, keyboard, mouse, and file storage terminal.

[0050] Furthermore, the first control processing module 31 is an FPGA, the second control processing module 32 is an ARM processor, the first storage module 33 is a dual-port RAM, and the second storage module 34 is an SD CARD.

[0051] Among them, the FPGA uses the chip EP4CE40 and the ARM processor uses the chip SOM3730.

[0052] like Figure 1 and Figure 3 As shown, the monitoring board 3 further includes a display interface module 37, the display interface module 37 is connected to the second control processing module 32, and the display interface module 37 is also connected to the back panel 4;

[0053] The display panel 5 includes a display 501 , which is connected to the back panel 4 .

[0054] It should be noted that the display interface module 37 includes a digital-to-analog conversion chip ADV7125 and a FlatLink transmitter chip SN75LVDS83B, and the DSS signal sent by the second control processing module 32 is converted into a VGA signal through the digital-to-analog conversion chip ADV7125 and into an LVDS signal through the FlatLink transmitter chip SN75LVDS83B for debugging and interface display. Among them, the display 501 can be a touch screen.

[0055] Further, the display panel 5 includes an LED module 502, and the LED module 502 is connected to the back panel 4;

[0056] The display panel 5 further includes a USB interface 503 or an RS485 interface 503 , and the USB interface 503 or the RS485 interface 503 is connected to the back panel 4 .

[0057] Among them, the LED module is mainly used to indicate the device power supply, operating status, alarm and fault information, the USB interface 503 is used for file copying, and the RS485 interface 503 is used for online debugging.

[0058] See also Figure 4 , is a schematic diagram of the structure of an embodiment of a switch quantity board of the online power quality monitoring device provided by the present invention. Figure 4 As shown, the switch quantity board 2 includes a first connection terminal 21, a second connection terminal 22, an input optical coupler 23, an output optical coupler 26, a relay driving module 25, a relay 24 and a programmable logic device 27;

[0059] The first connecting terminal 21 is connected to the input optocoupler 23, the input optocoupler 23 is connected to the programmable logic device 27, the programmable logic device 27 is connected to the backplane 4, the programmable logic device 27 is also connected to the output optocoupler 26, the output optocoupler 26 is connected to the relay drive module 25, the relay drive module 25 is connected to the relay 24, and the relay 24 is connected to the second connecting terminal 22.

[0060] It should be noted that the switch quantity board 2 is mainly used to collect line switch quantities, such as monitoring the opening and closing position information of the line switch, and the output quantity is mainly used for output device alarms, faults and other nodes.

[0061] The invention provides an online power quality monitoring device, wherein M analog quantity boards collect electric signals of a power grid, convert the collected electric signals into digital signals and then send them to a backboard; N switch quantity boards collect binary input signals and send the collected binary input signals to the backboard, and the multiple monitoring channels formed by the M analog quantity boards and the N switch quantity boards can monitor some long-term power quality parameters, thereby improving the reliability of power quality monitoring; the monitoring board obtains digital signals and binary input signals from the backboard, analyzes and calculates the digital signals and the binary input signals to obtain power quality parameters and recording start parameters, and starts recording according to the recording start parameters and sends the power quality parameters to the backboard; the display board obtains power quality parameters from the backboard and displays the power quality parameters, and simultaneously has the functions of power quality monitoring and fault recording, thereby improving the reliability of power quality monitoring and reducing the manufacturing cost of the equipment.

[0062] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. An online power quality monitoring device, characterized in that: Includes M analog boards, N switches The M analog quantity boards, N switch quantity boards, monitoring board, backboard and display board are all connected to the backboard; The M analog panels are used to collect electrical signals from the power grid, and convert the collected electrical signals into digital signals and then send them to the backplane; The N switch quantity boards are used to collect binary input quantity signals and send the collected binary input quantity signals to the backplane; The monitoring board is used to obtain the digital signal and the binary input signal from the backboard, analyze and calculate the digital signal and the binary input signal to obtain power quality parameters and recording start parameters, and start recording according to the recording start parameters and send the power quality parameters to the backboard; The display panel is used to obtain the power quality parameter from the back panel and display the power quality parameter; Wherein, the monitoring board includes a first control processing module for acquiring the digital signal and the binary input signal from the backplane, a second control processing module for analyzing and calculating the digital signal and the binary input signal, a first storage module and a second storage module; The first control processing module is connected to the first storage module, the second control processing module is connected to the second storage module, and the first control processing module is in communication connection with the second control processing module; The first control processing module is an FPGA, the second control processing module is an ARM processor, the first storage module is a dual-port RAM, and the second storage module is an SDCARD; Wherein, the analog quantity board includes a signal acquisition module for acquiring electrical signals of the power grid, an analog signal processing module, an AD acquisition module and a programmable logic device; The signal acquisition module is connected to the analog signal processing module, the analog signal processing module is connected to the AD acquisition module, the AD acquisition module is connected to the programmable logic device, The programmable logic device is connected to the backplane; Wherein, the switch quantity board includes a first connection terminal, a second connection terminal, an input optical coupler, an output optical coupler, a relay drive module, a relay and a programmable logic device; The first connection terminal is connected to the open-input optocoupler, the open-input optocoupler is connected to the programmable logic device, the programmable logic device is connected to the backplane, the programmable logic device is also connected to the open-output optocoupler, the open-output optocoupler is connected to the relay drive module, the relay drive module is connected to the relay, and the relay is connected to the second connection terminal.

2. The power quality online monitoring device according to claim 1, characterized in that: The signal acquisition module includes four voltage transformers for acquiring voltage signals of the power grid and four current transformers for acquiring current signals of the power grid.

3. The online power quality monitoring device according to claim 1, characterized in that: The monitoring board further comprises a USB interface module, an Ethernet interface module and an RS485 interface module connected to external communication, and the USB interface module, the Ethernet interface module and the RS485 interface module are all connected to the second control processing module.

4. The online power quality monitoring device according to claim 1, characterized in that: The monitoring board further comprises a display interface module, the display interface module is connected to the second control processing module, and the display interface module is also connected to the backplane; The display panel includes a display connected to a back panel.

5. The online power quality monitoring device according to claim 1, characterized in that: The display panel includes an LED module, and the LED module is connected to a back panel; The display panel also includes a USB interface or an RS485 interface, and the USB interface or the RS485 interface is connected to the back panel.

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