CN211206604U - Mobile electrical equipment on-line monitoring device - Google Patents

Abstract

On-line monitoring device for mobile electrical equipment, including box body, detection test leads, three-phase current, voltage, temperature test ports, liquid crystal display, power switch, and power indicator light on the box panel; the box body includes a power module, three-phase phase Current and voltage monitoring modules, temperature monitoring modules; the power switch is connected with the power indicator light; the monitoring modules are respectively connected with the test ports, and the test leads are connected with the test ports; the three-phase phase current monitoring module includes open current transformers that are electrically connected in sequence , signal conditioning module; the voltage monitoring module includes a voltage transformer and a voltmeter connected to its secondary side; the temperature monitoring module includes an infrared sensor module, the signal conditioning module, the infrared sensor module and the single-chip control module are connected; the single-chip control module is connected to the LCD LCD monitor connection.

Description

An online monitoring device for mobile electrical equipment

technical field

The utility model relates to a monitoring device, in particular to the design of an online monitoring device for mobile electrical equipment.

Background technique

Now important places and important activities are constantly being carried out. In traditional major service guarantees, due to the aging of electrical cabinets (equipment), there is no installation of operation monitoring devices or temporarily added electrical cabinets (equipment) lack of operation monitoring devices. Although special personnel are set up in the area to monitor important equipment, it is impossible to grasp the overall operating status of the equipment in real time, and there is no prediction before the abnormal situation of the equipment occurs, resulting in unnecessary accidents.

Prior art, such as Chinese patent application (application number: CN2018105563059) discloses an application system based on equipment state monitoring, including: equipment temperature detection module, current detection module, voltage detection module, harmonic detection module, processing module, communication module and Remote server; equipment temperature detection module, current detection module, voltage detection module, harmonic detection module and communication module are all electrically connected to the processing module, and the communication module is signally connected to the remote server; equipment temperature detection module, current detection module, voltage detection module The harmonic detection module and the harmonic detection module are arranged on the surface of the electrical equipment in sequence; the processing module and the communication module are arranged inside the electrical equipment, the electrical equipment is provided with a power supply module, and the power supply module is respectively electrically connected with the processing module and the communication module. For another example, in the prior art, Chinese patent application (application number: CN2018104978187) discloses a power line automatic fault detection and positioning system, comprising: a display unit for detecting real-time data of the power line and outputting the real-time data of the power line according to the real-time data. Status information; an alarm unit, which is used to alert the staff when the real-time data of the power line is not in conformity with the safety range of the data in the database; a data acquisition module, which is connected to the electric energy meter through the RS485 bus for data acquisition, The main control chip is used to receive the signal transmitted by the theoretical calculation and analysis module, and transmit it to the display unit, the alarm unit and the Internet terminal through the communication module.

However, the above application only gives an idea, and does not describe what technical means are used to realize equipment status monitoring and fault detection. That is to say, the working principle of the above application is not recorded, but only provides information such as temperature detection module and current monitoring module. , voltage monitoring module, processing module, display unit and other functional modules, the structure of the above-mentioned functional modules is not recorded, although there are above-mentioned functional modules in the prior art, but applying all the above-mentioned prior art functional modules to the present application does not belong to The prior art can only be obtained by those skilled in the art with creative work.

For another example, in the prior art, a Chinese patent (application number: CN2017212075864) discloses a power distribution monitoring system, the technical solution of which is to include a microprocessor unit, a three-phase electrical parameter measurement unit connected to the microprocessor unit, a temperature a detection module, a time monitoring unit, an alarm unit and a power quality analyzer; a temperature detection module, which is used to detect the temperature of the collected and monitored power equipment, and transmit the detected temperature value to the microprocessor unit; the microprocessor unit It is also connected with the communication unit, and the communication unit is used to send the alarm information including the current, voltage alarm module, time alarm module, temperature alarm module and harmonic alarm module to the terminal; the three-phase electrical parameters The calculation unit includes a three-phase electrical parameter measuring chip ATT7022, a current transformer and a current transformer. The sampling voltage input of the three-phase electrical parameter measuring chip ATT7022 adopts the resistance division method, and the current transformer converts the sampling input voltage into a secondary voltage analog signal , the current transformer converts the sampled input voltage into a voltage analog signal. However, the prior art is not portable, and the technical means used are complex in structure, and the detection accuracy is not high enough, which is not conducive to the application and promotion of the product.

Utility model content

In order to solve the deficiencies in the prior art, the utility model discloses an on-line monitoring device for mobile electrical equipment. Voltage test port, temperature test port, liquid crystal display, power switch, power indicator light; the inside of the box includes a power module, a three-phase phase current monitoring module, a three-phase phase voltage monitoring module, a temperature monitoring module, and a voltmeter; its features The steps are as follows: the power module is connected to one phase of the three-phase power through a power switch and a fast recoverable fuse, and the power switch is also connected to a power indicator light; each of the monitoring modules is respectively connected to each test port on the box panel wherein the three-phase phase current monitoring module includes an open current transformer and a signal conditioning module that are electrically connected in sequence; the three-phase phase voltage monitoring module includes a voltage transformer and a voltmeter connected to the secondary side of the voltage transformer; the temperature monitoring module includes an infrared sensor module; the signal conditioning module in the three-phase phase current monitoring module and the infrared sensor module in the temperature monitoring module are controlled by a single-chip microcomputer The module is connected; the single chip control module is connected with the LCD liquid crystal display.

Preferably: the output terminal of the open current transformer is connected to the LM324 integrated operational amplifier, and two reverse diodes are added to the input terminal of the integrated operational amplifier to protect the operational amplifier; the output terminal of the integrated operational amplifier and the negative terminal input The connected feedback resistor is a precision resistor.

Preferably, the signal output from the output terminal of the LM324 integrated operational amplifier first uses the first operational amplifier to realize half-wave rectification, so that the AC signal only retains the negative half cycle, and because it is connected to the inverting input terminal of the operational amplifier, the result is an inversion The negative half cycle of the phase is then connected to an adder, and the non-inverting input terminal is used to add the input AC signal and twice the half-wave rectified signal to obtain a full-wave positive signal.

Preferably: the full-wave forward signal is connected to the A/D conversion module; the A/D conversion module adopts the chip model ADC0809, and the output end of the chip ADC0809 is connected to the I/O port of the single-chip AT89C51; the ADC0809 chip is externally connected A clock signal with a frequency of 500kHz.

Preferably, the voltage transformer is an electromagnetic induction voltage transformer.

Preferably, the infrared sensor module includes a model MLX90615 high-precision temperature measurement chip.

Preferably, the infrared sensor module is connected to the single-chip control module by SMBus, the SDA and SCL pins in the MLX90615 chip are connected to the I/O port of the single-chip AT89C51, and the power supply voltage is 3.3V through a 20kΩ pull-up resistor. connected.

Preferably, the three-phase voltage monitoring module adopts three single mutual inductors to form a three-phase voltage transformer, and is connected to the three-phase busbar by sequentially connecting fuses and relay normally open contacts.

Beneficial effects:

1. The current transformer adopts an open-type current transformer. The open-type current transformer has the characteristics of easy measurement and convenient use. The current transformer and the voltage measurement probe (clamp) are connected with the multi-function meter through a stretchable winding wire, and the display actual voltage and current;

2. Use quick-plug connectors for connection, optimize the space utilization of the testing equipment, and enhance the mobility and portability of the equipment.

3. On the basis of not changing the original electrical equipment, real-time online monitoring of the voltage, current and temperature of the equipment that does not meet the installation detection device is carried out, which is convenient for major event support personnel to grasp the equipment operation data in real time and reduce the probability of accidents.

Description of drawings

Figure 1 is a schematic structural diagram of the on-line monitoring device for mobile electrical equipment of the present invention.

Fig. 2 is the control structure diagram of the on-line monitoring device of the mobile electrical equipment of the present invention.

3 is a schematic diagram of the three-phase current monitoring and control structure of the online monitoring device for mobile electrical equipment of the present invention.

4 is a schematic diagram of the current-voltage conversion circuit in the three-phase current monitoring module of the mobile electrical equipment online monitoring device of the present invention.

5 is a schematic diagram of the signal conditioning circuit in the three-phase current monitoring module of the mobile electrical equipment online monitoring device of the present invention.

6 is a schematic diagram of the connection circuit between the analog-to-digital conversion chip and the single-chip microcomputer in the three-phase current monitoring module of the mobile electrical equipment online monitoring device of the present invention.

FIG. 7 is a structural block diagram of the infrared monitoring module in the on-line monitoring device for mobile electrical equipment of the present invention.

FIG. 8 is a block diagram of the MLX90615 chip structure in the temperature monitoring module of the online monitoring device for mobile electrical equipment of the present invention.

9 is a circuit diagram of the connection between the MLX90615 chip and the single-chip microcomputer in the temperature monitoring module of the mobile electrical equipment online monitoring device of the present invention.

10 is a schematic diagram of the circuit connection of the voltage monitoring module of the online monitoring device for mobile electrical equipment of the present invention.

Detailed ways

The following description is used to disclose the present invention to enable those skilled in the art to implement the present invention. The preferred embodiments described below are given by way of example only, and other obvious modifications will occur to those skilled in the art.

An on-line monitoring device for mobile electrical equipment, the technical scheme of which is as follows: comprising a box body, and a three-phase current and three-phase voltage test port, a temperature test port, a liquid crystal display, a power switch, and a power indicator light are arranged on the panel of the box body; The inside of the box body includes a power module, a three-phase current and three-phase voltage monitoring module, a temperature monitoring module, and a detection test lead. One phase is connected, and the power switch is also connected to the power indicator light; each of the monitoring modules is connected to each test port on the box panel, and the test lead can be connected to the above test port; wherein, the three-phase phase The current monitoring module includes an open current transformer and a signal conditioning module that are electrically connected in sequence; the three-phase voltage monitoring module includes a voltage transformer and a voltmeter connected to the secondary side of the voltage transformer; the temperature monitoring module includes an infrared The sensor module, the signal conditioning module and the infrared sensor module in the three-phase phase current monitoring module are connected with the single-chip control module; the single-chip control module is connected with the LCD liquid crystal display. The output end of the open current transformer is connected to the LM324 integrated operational amplifier, and two reverse diodes are added to the input end of the integrated operational amplifier to protect the operational amplifier; the feedback of the output end of the integrated operational amplifier connected to the negative end input The resistors are precision resistors. The signal output from the output terminal of the LM324 integrated operational amplifier first uses the first operational amplifier to realize half-wave rectification, so that the AC signal only retains the negative half cycle, and because it is connected to the inverting input terminal of the operational amplifier, the result is an inverted negative phase. Half cycle, followed by connection with an adder, using the non-inverting input terminal to add the input AC signal and twice the half-wave rectified signal to obtain a full-wave forward signal. The full-wave forward signal is connected with the A/D conversion module; the A/D conversion module adopts the chip model ADC0809, and the output end of the chip ADC0809 is connected with the I/O port of the single-chip AT89C51; the external frequency of the ADC0809 chip is 500kHz clock signal. The voltage transformer is an electromagnetic induction voltage transformer. The infrared sensor module includes a model MLX90615 high-precision temperature measurement chip. The infrared sensor module is connected to the single-chip control module by SMBus. The SDA and SCL pins in the MLX90615 chip are connected to the I/O port of the single-chip AT89C51, and are connected to the power supply voltage of 3.3V through a 20kΩ pull-up resistor. The three-phase voltage monitoring module adopts three single mutual inductors to form a three-phase voltage transformer, and is connected to the three-phase busbar by sequentially connecting fuses and relay normally open contacts.

The structures and working principles of the three-phase phase current monitoring module, the three-phase phase voltage monitoring module and the temperature monitoring module are described in detail below.

For the working principle and structure of the three-phase phase current monitoring module, please refer to the accompanying drawings 3-6 in the specification.

The three-phase current monitoring module designed by the present invention obtains the real-time value of the current by sampling the three-phase current, uses the single-chip microcomputer to process and calculate the data, displays the result on the LCD in real time, and compares and observes the displayed current data. , to detect the working condition of the three-phase current in the electrical box equipment.

The three-phase phase current monitoring module includes an open current transformer, a signal conditioning module, and a single-chip control module that are electrically connected in sequence.

The open current transformer collects the three-phase current signal in the electrical box, converts the current signal into a voltage signal, and converts the analog signal into a digital signal through the A/D converter in the signal conditioning module and transmits it to the single-chip microcomputer The control module displays the collected current signal on the LCD screen through the single-chip control module.

The above working principle is further described as follows: Please refer to Figure 4. The circuit diagram is the schematic diagram of the conversion circuit that converts the current signal into a voltage signal after the current transformer collects the three-phase current. This circuit principle uses the LM324 integrated operational amplifier as the current The main component of the conversion, the voltage after the current conversion can be controlled according to the size of the feedback resistor R3, the feedback resistors R1, R2, R3 are required to use precision resistors, and the input end of the LM324 integrated operational amplifier adds two reverse diodes. is the protection op amp.

The phase current is converted into a voltage signal through the above circuit. Since the converted voltage signal is relatively weak, signal processing must be performed on the voltage signal to enhance the signal strength. Please refer to Figure 5 for the specific circuit structure. The schematic diagram of the circuit first uses an operational amplifier to realize half-wave rectification, so that the AC signal only retains the negative half cycle, and because it is connected to the inverting input of the operational amplifier, the result is an inversion The negative half cycle of , followed by a precision adder, which uses the non-inverting input terminal to add the input AC signal with twice the half-wave rectified signal, and finally obtains the full-wave positive direction signal. The operational amplifier used in the schematic diagram of the circuit can be selected as op07 chip or 741 chip.

After the collected current signal is processed to form a stable and reliable voltage signal through the circuit diagram shown in Figure 4-5, it will be A/D converted. The A/D conversion chip used in the present invention adopts ADC0809. The chip ADC0809 is With 8-bit A/D converter, 8-way multiplexer and microprocessor-compatible control logic CMOS components, it is a successive approximation A/D converter, which can be directly interfaced with the microcontroller AT89C51. There is no clock circuit, the required clock signal must be provided by the outside world, usually the frequency used is 500kHz.

The open current transformer used in the present invention has a transformation ratio of 2000:1, that is to say, if the input current on the primary side is 5A, the effective value of the current on the secondary side is 2.5mA. Between 0.3 ~ 5V, so its sampling resistance is 1k ohms. The single-chip microcomputer uses a 12MHz crystal oscillator, and the ALE port will issue a fixed clock frequency divided by 6, that is, 2MHz, so it is necessary to connect a circuit of 4 frequency division externally; you can choose two separate D flip-flops, such as 74LS74 to complete the frequency division purpose .

离散化，以一个周期内有限个采样电压数字量来代替一个周期内连续变化的电压值，则有：

In addition, since the multi-way switch is used to select the A, B, and C phases of the three-phase current, the AD conversion resources need to be used in time-sharing, so there is the problem of time-sharing and channel-dividing of the three-phase AC. Therefore, the present invention adopts one cycle That is, 66 sampling points can be sampled within 50Hz. Considering the reliability of sampling, 50 sampling points are taken for each phase in one cycle. If the voltage RMS formula is:

In discretization, a finite number of sampled voltage digital quantities in a cycle are used to replace the continuously changing voltage value in a cycle, then there are:

In the formula: ΔT _m is the time interval of two adjacent samplings, Um is the instantaneous value of voltage sampling at the m-1 time interval; N is the number of sampling points in one cycle; if the time intervals of two adjacent samplings are equal, that is, ΔT _m is a constant ΔT, and considering N=(T/ΔT)+1, there are

Equation (2) is a formula for calculating the effective value of the voltage signal according to the instantaneous value of each sampling in one cycle and the number of sampling points per cycle. Using the above voltage formula to calculate the sampling value, the influence of sampling 50 points per phase per cycle on the sampling accuracy can be analyzed, and the average value is obtained at the same time and then compared with the theoretical calculation value, and the average value of the error is found to compensate the output signal. The display shows the rms value of the current amplitude.

For the working principle and structure of the temperature monitoring module, please refer to Figures 7-9 in the description.

The utility model adopts a temperature monitoring module including a high-precision temperature measurement chip produced by Melexis Company, whose model is: MLX90615. The internal structure of the chip consists of an infrared temperature sensor, a low-noise amplifier, an A/D converter, a DSP unit, a pulse width Modulation circuit and logic control circuit (see Figure 8), the temperature signal output by the thermocouple is sent to the analog/digital converter after passing through the internal operational amplifier, and the output 16-bit digital quantity is processed by a low-pass filter and then output. The output is stored in the internal RAM unit as the measurement result, and can be read through SMBus; at the same time, the measurement result is sent to the post-stage digital pulse width modulation circuit, and the test result is output in PWM mode. The infrared sensor is selected to be connected to the microcontroller by SMBus. Please refer to Figure 9 for the schematic diagram of the connection circuit. Among them, the SDA and SCL pins in the MLX90615 chip are connected to the I/O port of the microcontroller, and are connected to the power supply through a 20kΩ pull-up resistor. The voltage is connected to 3.3V.

By sending commands to the infrared sensor, the microcontroller can write the data into the EEPROM inside the sensor, or read the temperature data stored in the RAM. When the infrared sensor MLX90615 receives the external infrared signal, it outputs the digital temperature after the internal processing of the sensor. The signal is sent to the single-chip microcomputer, and the single-chip computer processes the read data and displays the temperature data on the LCD1602. Since the direction of the temperature acquisition signal is that the single-chip microcomputer points to the liquid crystal module, the enable terminal/OE is grounded, and the DIR terminal is connected to the VCCA terminal. The data and control ports of LCD1602 are connected with the I/O port of the microcontroller after being converted by the SN74LVCC3245A chip.

In addition, in the temperature monitoring module, the AT89 C51 microcontroller and the infrared sensor MLX90615 need 3.3V power supply, while the liquid crystal display module LCD1602 needs a power supply voltage of 5V. The power design is powered by a 9V battery to increase the portability of the infrared thermometer. Two LM317s are used to convert the 9V battery voltage into 5V and 3.3V respectively to meet the needs of two power supply voltages.

Please refer to Figure 10 in the description for the working principle and structure of the phase voltage monitoring module.

In order to save the design cost, the phase voltage detection module designed by the present invention includes a voltage transformer and a voltmeter. The phase voltage is collected through the voltage transformer, and the collected phase voltage signal is directly connected to the voltmeter to display the three-phase voltage.

The specific circuit is shown in Figure 10 of the specification. The utility model adopts three single mutual inductors to form a three-phase voltage transformer, and is connected with the three-phase busbar by sequentially connecting the fuse and the normally open contact of the relay. Because the impedance of the voltage transformer itself is small, once the secondary side is short-circuited, the current will increase sharply and the coil will be burned. For this reason, the primary side of the voltage transformer is connected with a fuse and a relay switch, and its secondary side is reliably grounded to avoid the primary and secondary sides being insulated. When damaged, the secondary side has a high potential to ground, causing equipment accidents. In addition, the connection method of the voltage transformer of the present invention adopts the connection method of the three-phase three-column transformer. The advantage of this connection method is that the neutral point of the high-voltage side is grounded, so the insulation level and cost can be reduced, and the voltage transformer group is Designed according to the phase voltage, it can measure both line voltage and phase voltage; in addition, the auxiliary winding of the secondary side open delta can be used for insulation monitoring.

The utility model is mainly used in major event sites, old equipment and temporary equipment running state monitoring devices without installation condition monitoring devices in important places, and can also be used for equipment failure analysis and state evaluation. This device has the characteristics of simple structure, strong portability, comprehensive measurement data, and high cost performance. In the support of various major activities, it can monitor the corresponding equipment in real time at any time as needed, and grasp the operating parameters of the equipment at any time, so that the service support work can be scientific and intelligent. Excessive level of chemistry.

The basic principles, main features and advantages of the present invention have been shown and described above. It should be understood by those skilled in the art that the present invention is not limited by the above-mentioned embodiments, and the above-mentioned embodiments and descriptions describe only the principles of the present invention. There are various changes and improvements that fall within the scope of the claimed invention. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims (8)

1. The mobile electrical equipment on-line monitoring device comprises a box body and a detection meter pen, wherein a three-phase current and three-phase voltage testing port, a temperature testing port, a liquid crystal display, a power switch, a power indicator lamp and a voltmeter are arranged on a panel of the box body, a power module, a three-phase current monitoring module, a three-phase voltage monitoring module and a temperature monitoring module are arranged inside the box body, and the mobile electrical equipment on-line monitoring device is characterized in that the power module is connected with one of three phases of electricity through the power switch and a quick-recovery fuse tube, the power switch is also connected with the power indicator lamp, each monitoring module is respectively connected with each testing port on the panel of the box body, the detection meter pen can be connected with the testing port, the three-phase current monitoring module comprises an open type current transformer and a signal conditioning module which are sequentially and electrically connected, the three-phase voltage monitoring module comprises a voltage transformer and a voltmeter connected with the secondary side of the voltage transformer, the temperature monitoring module comprises an infrared sensor module, the signal conditioning module in the three-phase current monitoring module and the infrared sensor module in the temperature monitoring module are.

2. The on-line monitoring device of mobile electrical equipment as claimed in claim 1, wherein the output end of the open type current transformer is connected with L M324 integrated operational amplifier, two reverse diodes are added to the input end of the integrated operational amplifier to protect the operational amplifier, and a feedback resistor connected between the output end of the integrated operational amplifier and the input end of the negative terminal is a precision resistor.

3. The in-line monitoring device of claim 2, wherein the L M324 integrated operational amplifier outputs a signal that is first half-wave rectified by the first operational amplifier so that the AC signal only remains negative for the negative half-cycle, and then the negative half-cycle is inverted by the inverting input of the operational amplifier, and then connected to an adder that adds the input AC signal to twice the half-wave rectified signal by the non-inverting input to obtain a full-wave positive signal.

4. A mobile electrical equipment on-line monitoring device according to claim 3, characterized in that: the full-wave forward signal is connected with the A/D conversion module; the A/D conversion module adopts a chip with the model number of ADC0809, and the output end of the chip ADC0809 is connected with an I/O port of a singlechip AT89C 51; the ADC0809 chip is externally connected with a clock signal with the frequency of 500 kHz.

5. A mobile electrical equipment on-line monitoring device according to claim 1, characterized in that: the voltage transformer is an electromagnetic induction type voltage transformer.

6. The on-line monitoring device for the mobile electrical equipment as claimed in claim 1, wherein the infrared sensor module comprises a high-precision temperature measuring chip with the model number of M L X90615.

7. The mobile electric equipment on-line monitoring device of claim 6, wherein the infrared sensor module is connected to the single chip microcomputer control module in SMBus mode, SDA and SC L pins in the M L X90615 chip are connected with the I/O port of the single chip microcomputer AT89C51, and are connected with the supply voltage of 3.3V through a pull-up resistor of 20k Ω.

8. A mobile electrical equipment on-line monitoring device according to claim 1, characterized in that: the three-phase voltage monitoring module adopts three single-phase transformers to form a three-phase voltage transformer and is connected with a three-phase bus through a fuse and a relay normally open contact which are connected in sequence.

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