CN215180640U - Power grid off-line insulation state monitoring system - Google Patents
Power grid off-line insulation state monitoring system Download PDFInfo
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- CN215180640U CN215180640U CN202120731783.6U CN202120731783U CN215180640U CN 215180640 U CN215180640 U CN 215180640U CN 202120731783 U CN202120731783 U CN 202120731783U CN 215180640 U CN215180640 U CN 215180640U
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Abstract
The utility model discloses a power grid off-line insulation state monitoring system. The intelligent monitoring system comprises a microcontroller module, a signal generating module and a signal receiving module, wherein the signal generating module can continuously inject square wave signals between a monitoring device circuit and the ground, a self-checking unit is connected between the microcontroller module and the ground, the self-checking unit comprises a front stage operational amplifier circuit and a rear stage operational amplifier circuit, the negative input end of the front stage operational amplifier circuit is grounded through a resistor RE3 and a resistor RE1 respectively through an independent grounding wire Ke and is connected with a common end through a resistor RE2, and the output end of the rear stage operational amplifier circuit is connected with an analog-to-digital conversion circuit of the microcontroller module through a resistor R104. The advantages are that: the purpose of monitoring the system off-line in the insulating state and improving the safety is achieved, the use stability and reliability of the self-checking circuit are improved, and therefore the self-checking can be reliably carried out by using the circuit of the self-checking unit, and the running condition of the ship equipment fault diagnosis device is continuously monitored.
Description
Technical Field
The utility model relates to a monitoring system for boats and ships deck machinery, specifically speaking are electric wire netting off-line insulation status monitoring system.
Background
Along with the development of ship equipment, the required capacity of a power system of a ship is continuously increased, the structure of a power network is more and more complex, and particularly, the wide application of a radio interference prevention capacitor greatly increases the ground capacitance of the power system of the ship, so that the electrical connection between a power grid phase line of the ship and a ship body can be generated; particularly, the environment of the mechanical equipment on the ship deck is severe, and the insulation fault of the power system is easily caused by the influence of salt mist, water vapor, mould and other factors; and complicated wiring conditions of a power grid system cause the problems from high-resistance grounding of equipment or a power grid line to direct metal grounding to occur, the amplitude variation range of grounding current is large, if insulation faults occur in time, more serious accidents such as fire, interphase short circuit, personnel electric shock and the like are easily caused, the life safety of ships and passengers is greatly threatened, but fault grounding residual current generated by single-phase short circuit faults of a neutral point ungrounded system is small, and fault line selection is difficult.
In the current stage, the insulation state of each line is monitored in real time, manual inquiry is mostly used, or a power grid online edge-closing device is used, the manual inquiry mode is troublesome and labor-consuming, once the ship insulation fault occurs, the insulation fault point can be positioned (searched) only by manually powering off hundreds of load branches one by one; the on-line insulation monitoring device of the power grid is adopted, although the insulation condition of a power grid line in a power-on state can be conveniently detected, the deck machinery generally does not operate for a long time, the system is not powered in a non-operating state, the insulation fault problem cannot be found in an on-line detection mode, and at the moment, once the system is powered suddenly, a large safety problem may occur, so that the system off-line monitoring on the insulation condition of the power system of the deck machinery is realized; the method has the advantages that the insulation fault is found and the fault line is diagnosed under the condition that the power system is not powered, and the method has very important significance for maintaining equipment, quickly removing faults and guaranteeing the use safety of power supply of a deck mechanical power system for operators.
Disclosure of Invention
The to-be-solved technical problem of the utility model is to provide a not only can carry out the off-line monitoring of system to marine equipment electric power system's insulating state, can reliably carry out the self-checking moreover to continuously monitor marine equipment failure diagnosis device operation conditions's electric wire netting off-line insulating state monitoring system.
In order to solve the technical problem, the utility model discloses a power grid off-line insulation state monitoring system, including microcontroller module, signal generation module and signal receiving module with microcontroller module communication, signal generation module can be continuously to the monitoring facilities circuit with ground between the injection square wave signal, signal receiving module can receive and connect the signal of monitoring facilities circuit two items and carry out the amplification filtering process, be connected with the self-checking unit of continuous monitoring facilities operation condition between microcontroller module and the ground, the self-checking unit includes two-stage operation amplifier circuit in front and back, the negative input end of the operation amplifier circuit of the preceding stage adopts independent earth connection Ke ground connection and connects the common terminal through a resistance RE2 after a resistance RE3 respectively through a resistance RE1, the output end of the operation amplifier circuit of the following stage connects the analog-to-digital conversion circuit of microcontroller module through a resistance R104, the output end of the previous stage operational amplification circuit and the negative input end of the next stage operational amplification circuit are connected in series with a resistor R80.
The positive input end of the operational amplifier circuit of the next stage is connected to a reference voltage through a resistor R47, and the positive input end of the operational amplifier circuit of the next stage is also connected to a common end through a resistor R49.
The negative input end and the output end of the operational amplification circuit of the former stage are directly connected, and the resistor R81 is connected in series between the negative input end and the output end of the operational amplification circuit of the latter stage.
A branch circuit which is connected with the common end through a capacitor C104 is arranged between the resistor R104 and the analog-digital conversion circuit of the microcontroller module.
The signal generation module circuit comprises an optical coupling switch and a plurality of triodes connected with the optical coupling switch, and the signal generation module circuit can generate a low-frequency square wave signal of 2.5Hz under the control of the microcontroller module.
The microcontroller module is also connected with an alarm unit, and can calculate and analyze the received signals to obtain the line resistance value and send alarm information through the alarm unit.
The alarm unit comprises an alarm indicator light and an LCD display screen.
The microcontroller module is also connected with a key switch for alarming, confirming and adjusting the set value of the alarm value.
The microcontroller module is also connected with a communication module for transmitting the alarm signal to the upper computer equipment.
The microcontroller module is also connected with a power module.
The microcontroller module employs an STM32F407ZGT6 chip.
The invention has the advantages that:
(1) the low-frequency square waves are ingeniously injected between two phases of a line of the equipment and the ground, the voltage of sampling resistors of the two phases of a connecting circuit is monitored, Fourier transform is used for processing sampling data to calculate the insulation resistance of the circuit, the insulation state of the line is judged, an alarm is given when the line has an insulation fault, the purpose of monitoring the insulation state of a ship equipment power system in a system off-line mode is achieved, and the safety is improved.
(2) The self-checking circuit is provided with a plurality of resistors and voltage stabilizing devices with different functions matched with the front and rear two-stage operational amplification circuits by designing the circuit of the self-checking unit, so that the circuit is effectively protected, the use stability and reliability of the self-checking circuit are improved, the self-checking can be reliably carried out by utilizing the circuit of the self-checking unit, and the running condition of the ship equipment fault diagnosis device is continuously monitored.
Drawings
FIG. 1 is a schematic block diagram of a power grid offline insulation state monitoring system according to the present invention;
FIG. 2 is a circuit diagram of a signal generating module according to the present invention;
FIG. 3 is a circuit diagram of a self-test module according to the present invention;
FIG. 4 is a circuit diagram of a signal receiving module according to the present invention;
FIG. 5 is a schematic diagram of the operation of the off-line insulation state monitoring system of the power grid according to the present invention;
FIG. 6 is an equivalent circuit of the power grid offline insulation state monitoring system according to the present invention when the circuit is insulated;
FIG. 7 is a schematic diagram of the signal trend of the self-test module during the single Ke wiring and self-test.
Detailed Description
The off-line insulation state monitoring system of the power grid is further described in detail with reference to the accompanying drawings and the detailed description.
As shown in the figure, the power grid off-line insulation state monitoring system of this embodiment includes an STM32 microcontroller module, a signal generating module and a signal receiving module connected to the STM32 microcontroller module, the signal generating module can continuously inject square wave signals between a monitoring device line and the ground, the signal receiving module can receive and amplify and filter two signals connected to the monitoring device line, a self-checking unit for continuously monitoring the operation status of the device is connected between the microcontroller module and the ground, the self-checking unit includes a front and a rear two-stage operational amplifier circuits, a negative input end of the front stage operational amplifier circuit is grounded via a resistor RE3 respectively via a resistor RE1 by using a single ground wire Ke and is connected to a common end via a resistor RE2, an output end of the rear stage operational amplifier circuit is connected to an analog-to-digital conversion circuit of the microcontroller module via a resistor R104, the output end of the previous operational amplifier circuit and the negative input end of the next operational amplifier circuit are connected in series with a resistor R80, the positive input end of the next operational amplifier circuit is connected with a reference voltage through a resistor R47, the positive input end of the next operational amplifier circuit is also connected with a common end through a resistor R49, the negative input end and the output end of the previous operational amplifier circuit are directly connected, a resistor R81 is connected in series between the negative input end and the output end of the next operational amplifier circuit, a branch circuit which is connected with the common end through a capacitor C104 is arranged between the resistor R104 and the analog-to-digital conversion circuit of the microcontroller module,
in particular, the circuit of the self-checking unit not only uses a single grounding wire Ke for grounding (figure 7), but also has a plurality of resistors and voltage stabilizing devices with different functions matched with a front operational amplifier circuit and a rear operational amplifier circuit, thereby effectively protecting the circuit, improving the use stability and reliability of the self-checking circuit, amplifying and receiving signals through the two-stage operational amplifier circuit, transmitting the signals to an STM32 microcontroller module, carrying out sampling analysis through an A/D conversion channel, monitoring and receiving the signals by utilizing an STM32 microcontroller module and judging the operation condition of the module, thereby continuously monitoring the operation condition of equipment through the self-checking module, connecting the STM32 microcontroller module with an alarm unit, controlling the whole module system by utilizing the STM32 microcontroller module, calculating and analyzing the received signals to obtain the resistance value of the circuit, and sending alarm information through the alarm unit when the calculated insulation resistance value is smaller than a set value, when alarm unit is alarm indicator lamp and LCD display screen, alarm indicator lamp is bright, LCD display screen shows alarm information, still be connected with key switch on the STM32 microcontroller module, communication module and power module, key switch is used for reporting to the police and confirms and adjustment alarm value setting value, communication module is used for transmitting alarm signal to host computer equipment, power module is responsible for supplying power for a whole set of device, can measure the insulation resistance of equipment circuit under the off-line condition from this, insulation monitoring's measurement display range does: 2k omega-5M omega pre-alarming, wherein the alarm setting range is as follows: 20k omega-5M omega, the power module that the device used includes 220V changes +/-24V, 5V power module and 5V changes +/-12V, 3.3V power module, wherein 24V voltage is used for signal injection voltage, 5V is used for supplying power to chips such as CAN, 12V is used for supplying power to operational amplifier circuit, 3.3V is used for supplying power to components such as CPU treater, when using, when off-line monitoring device normally works, the system will receive the square wave signal that signal generation module injects to ground Pe through independent earth connection Ke. If the injection signal generated by the signal generation module can not be detected, the operation of the module is judged to be failed, and the failure alarm of the module is displayed through an LCD screen and an alarm indicator lamp.
Further, for specific circuit design, the signal generation module circuit comprises an optical coupling switch and a plurality of triodes connected with the optical coupling switch, the optical coupling switch is AQW214EH, the SS8050 triodes are used for driving, the triodes are connected with +/-24 v in turn, a STM32 microcontroller module controls to generate 2.5Hz low-frequency square wave signals to be injected between any two phases of the monitored line and the ground Pe, the signal receiving module can adopt a conventional signal receiving circuit, and the embodiment does not limit the signal receiving circuit.
Furthermore, the STM32 microcontroller module uses STM32F407ZGT6 chip, the chip has fast processing speed, the dominant frequency of the chip reaches 168MHz, the chip has rich on-chip peripheral resources, the inside has 192KB on-chip SRAM and 1024KB Flash memory, 12 bit A-D conversion module with multiple channels, and multiple SPI, IIC and CAN communication interfaces, greatly simplifying the design of peripheral circuit, the communication module uses ADM2587E to isolate the communication device with ADM3053, simultaneously supports CAN and 485 communication, CAN rapidly transmit the insulation fault information to the upper computer system. The working principle is shown in fig. 5:
the power grid off-line insulation state monitoring system is in electrical linkage relation with a ship equipment line switch, the power grid off-line insulation state monitoring system is in a standby state when the ship equipment is powered on for use at ordinary times, when the ship equipment is disconnected by the line switch, the power grid off-line insulation state monitoring system starts to monitor the insulation state of a line, at the moment, a signal generating module continuously injects low-frequency square wave signals between two phases of the three-phase circuit and the ground Pe, and when the line has insulation faults (as shown in the figure), the injected signals return to an insulation monitoring device through grounding through a branch at a low insulation position, so that a circuit loop is formed, and an equivalent circuit shown in the figure 6 can be obtained.
Wherein Ef is the signal injection source, R0 is the sampling resistor, and R1 is the current limiting resistor. C is capacitance to ground, and Rf is insulation resistance. Because the neutral point of the power grid is not directly grounded, the line impedance is generally far smaller than the capacitance reactance value of the insulation resistance to the ground and the capacitance to the ground, the influence of the capacitance reactance value on the circuit can be ignored, and the fault can be obtained through calculation of ohm's lawInsulation resistance value Rf:
since the values of Ef, R0 and R1 are known, the insulation resistance Rf can be calculated by measuring the voltage U of the sampling resistor R0.
The collected signals are filtered and amplified by the signal collecting module and then are sampled and analyzed by an A/D conversion channel of an STM32 microcontroller module. Because the signal generation module injects a low-frequency signal into the circuit system, the a/D converter converts a continuous analog signal into a Discrete digital signal when sampling the signal, and the system cannot directly analyze and calculate the signal by using the numerical information of the acquired signal, so that the signal numerical value obtained by sampling is subjected to spectrum analysis by using Discrete Fourier Transform (DFT), the Discrete original data value is converted from the time domain to the frequency domain, and the extraction processing of the digital signal is performed in the frequency domain by using a numerical operation method. Assuming that the waveform function of the received low-frequency signal is x (t), first time domain sampling is performed on x (t) to obtain x (n) ═ x (nt), and then DFT is performed on x (n) to obtain:
the process of programming calculations in the STM32 chip may be represented by the Euler formula. DFT is carried out on the processing signal in a complex domain, a complex result can be obtained as long as the frequency of the injection square wave is determined, and then more accurate signal amplitude and phase are calculated according to the property of the complex. The method greatly increases the flexibility and accuracy of digital signal processing.
Comparing the calculated Rf with a resistance value set by a system, confirming the insulation state of a ship line where the monitoring equipment is located, triggering a pre-alarm or alarm function when the measured value of the insulation resistance is lower than the set value, lighting a pre-alarm (alarm) indicator lamp, and displaying line fault information by an LCD display screen. Meanwhile, the pre-alarming and alarming information CAN be transmitted to an upper computer system through a communication module by using CAN or 485 communication, and a crew is reminded of timely overhauling the insulation fault of the circuit.
Claims (10)
1. The utility model provides a power grid off-line insulation state monitoring system, includes microcontroller module, the signal generation module and the signal reception module with the communication of microcontroller module, the signal generation module can last to inject square wave signal between monitoring facilities circuit and the ground, and signal reception module can receive and connect two signals of monitoring facilities circuit and amplify filtering process, is connected with the self-checking unit who lasts monitoring facilities operation conditions between microcontroller module and the ground, the self-checking unit includes front and back two-stage operational amplification circuit, preceding one-level operational amplification circuit's negative input end adopts independent earth connection Ke ground connection and connects the common terminal through a resistance RE2 respectively through a resistance RE1 after a resistance RE3, the latter one-level operational amplification circuit's output is through the analog-to-digital conversion circuit that a resistance R104 connects microcontroller module, the preceding one-level operational amplification circuit's output and latter one-level operational amplification circuit's negative input end concatenates the negative input end concatenates There is a resistor R80.
2. The grid offline insulation state monitoring system according to claim 1, wherein: the positive input end of the operational amplifier circuit of the next stage is connected to a reference voltage through a resistor R47, and the positive input end of the operational amplifier circuit of the next stage is also connected to a common end through a resistor R49.
3. The grid offline insulation state monitoring system according to claim 1 or 2, characterized in that: the negative input end and the output end of the operational amplification circuit of the former stage are directly connected, and the resistor R81 is connected in series between the negative input end and the output end of the operational amplification circuit of the latter stage.
4. The grid offline insulation state monitoring system according to claim 3, wherein: a branch circuit which is connected with the common end through a capacitor C104 is arranged between the resistor R104 and the analog-digital conversion circuit of the microcontroller module.
5. The grid offline insulation state monitoring system according to claim 1, 2 or 4, wherein: the signal generation module circuit comprises an optical coupling switch and a plurality of triodes connected with the optical coupling switch, and the signal generation module circuit can generate a low-frequency square wave signal of 2.5Hz under the control of the microcontroller module.
6. The grid offline insulation state monitoring system according to claim 5, wherein: the microcontroller module is also connected with an alarm unit, and can calculate and analyze the received signals to obtain the line resistance value and send alarm information through the alarm unit.
7. The grid offline insulation state monitoring system according to claim 6, wherein: the microcontroller module is also connected with a key switch for alarming, confirming and adjusting the set value of the alarm value.
8. The grid offline insulation state monitoring system according to claim 6 or 7, wherein: the microcontroller module is also connected with a communication module for transmitting the alarm signal to the upper computer equipment.
9. The grid offline insulation state monitoring system according to claim 8, wherein: the microcontroller module is also connected with a power module.
10. The grid offline insulation state monitoring system according to claim 9, wherein: the microcontroller module employs an STM32F407ZGT6 chip.
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| CN202120731783.6U CN215180640U (en) | 2021-04-09 | 2021-04-09 | Power grid off-line insulation state monitoring system |
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| CN202120731783.6U CN215180640U (en) | 2021-04-09 | 2021-04-09 | Power grid off-line insulation state monitoring system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114520541A (en) * | 2022-01-14 | 2022-05-20 | 珠海多创科技有限公司 | Online monitoring method and monitoring system for power grid system line |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114520541A (en) * | 2022-01-14 | 2022-05-20 | 珠海多创科技有限公司 | Online monitoring method and monitoring system for power grid system line |
| CN114520541B (en) * | 2022-01-14 | 2023-09-22 | 珠海多创科技有限公司 | Online monitoring method and monitoring system for power grid system line |
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Address after: 212009 No. 19, Dingmao South Weier Road, Zhenjiang New District, Zhenjiang City, Jiangsu Province Patentee after: Zhenjiang saiernico Automation Co.,Ltd. Address before: 212000 Dingmao Nanwei 2nd Road, Zhenjiang New District, Jiangsu Province Patentee before: ZHENJIANG SAIERNICO AUTOMATION Co.,Ltd. |