CN111856129A - Detection method and detection system of large-scale comprehensive grounding system - Google Patents
Detection method and detection system of large-scale comprehensive grounding system Download PDFInfo
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Abstract
The invention relates to a detection method of a large-scale comprehensive grounding system. The method comprises the following steps: preparing before testing; acquiring potential gradient differences generated by all high-low voltage equipment grounding wires on a large grounding network in operation, and acquiring current values; thirdly, applying a current signal to the grounding grid by using the signal source device to accurately position dangerous points of the large grounding grid; fourthly, calculating the interference degree to a relay protection and automatic device, a telecontrol communication system and a signal system and the damage to the insulation of low-voltage equipment; fifthly, accurately and automatically drawing a curve graph of each technical index by a computer; and (VI) verifying. The invention utilizes the grounding short circuit current of the signal source analog system to display a plurality of data on the floor layout chart of the equipment area, and the computer calculates each technical index of the grounding network according to the current and potential distribution chart and uploads the technical index to the local area network so as to provide detailed real-time operation data of the grounding system for managers at any time.
Description
Technical Field
The invention relates to a method for detecting a large-scale comprehensive grounding system (network) of a power plant, a transformer substation, an electrified railway traction substation and a signal building command center and a detection system thereof.
Technical Field
Large earth systems, also known as large earth grids, are electrical devices that are important to be hidden underground. At present, in the domestic industries, the standard DL/T475-2006 "grounding device characteristic parameter measurement guide rule" issued in the power industry standard of the people's republic of China is executed in 2006, 10, 1, and a large grounding grid is measured by a tripolar method and a quadrapole method by adopting a grounding megger.
The "guidelines" stipulate detection techniques that cannot detect fault currents of large-scale network conduction systems and capability of releasing lightning currents, and cannot calculate contact voltages and site step voltages that threaten safety of personnel and equipment. The current potential distribution diagram generated in a large-scale comprehensive grounding system can not be measured by the grounding short circuit current generated in the power system and the working current of the electric locomotive of the electrified railway. The serious defects of the large-scale comprehensive grounding system cannot be detected, and the accurate position and various technical parameters of a fault point cannot be calculated. The operation parameters of the lightning protection grounding device of the equipment such as communication and signals along the electrified railway cannot be measured remotely, and the interference sources of the control, signals and communication signals along the electrified railway cannot be found.
The detection equipment and technology specified in the guide rule are not suitable for measuring and calculating the comprehensive grounding system of the power plant, the transformer substation and the electrified railway in operation and finished, and can not accurately position the fault point of the comprehensive grounding system of the electrified railway in an ultra-long distance. And reliable safety quality assessment cannot be performed on the large grounding grid.
The large-scale integrated grounding systems of power plants, transformer substations, traction substations of electrified railways and command centers of signal buildings all have hundreds of measuring points, and the detection technology specified in the guide rules can only measure the conduction and direct current resistance values among devices point by point. The direct-current resistance value has little practical significance to the fault analysis of the power system, and the grounding grid can not be proved to be qualified. The ground net for measurement needs to lay a test wire of 1000-2000 meters outside a plant station, people need to be dispatched to watch the wire in cities, and the wire needs to accompany the loss of young seedlings with farmers in rural areas, so that the labor intensity is very high.
Disclosure of Invention
The invention aims to provide a method for detecting a large-scale comprehensive grounding system of a power plant, a transformer substation, an electrified railway traction substation and a signal building command center and a detection system thereof, wherein the method has the advantages that: the signal source is used for simulating the system grounding short circuit current, safe electric signals are applied to a grounding network, a computer collects the voltage and the current on grounding wires of equipment such as a power plant, a transformer substation, an electrified railway signal building and the like, high-voltage and low-voltage electrical equipment, a cable shield, an electrified railway through grounding wire and the like, the voltage and the current are displayed on a device area plane layout diagram, and the computer calculates various technical indexes of the grounding network according to the current and potential distribution diagram and uploads the technical indexes to the local area network so as to provide detailed real-time operation data of the grounding system for managers at any time.
The technical scheme of the invention is as follows: a detection method of a large-scale integrated grounding system (network) comprises the following steps:
firstly, preparation before testing: firstly, connecting a ground wire of high-voltage and low-voltage equipment to be tested in a large-scale comprehensive grounding system to a test wire interface of a data acquisition device, transmitting acquired data to a data analysis computer by the data acquisition device, and adding a plurality of data acquisition devices according to the number of the test equipment; one port of current output on the signal source device is fixedly connected to one point on a grounding network as a reference zero potential reference point, the other output port of the signal source is connected to a grounding wire of high-voltage equipment to be tested according to the requirement, the data of the signal source is also required to be connected and transmitted to a data analysis computer, and the signal source device provides power for each data acquisition device;
for convenient connection, a plurality of data acquisition devices can be connected in series through 485 data acquisition lines and then connected to a data input port of a signal source device, and then connected to a data analysis computer through an output port of the signal source device;
secondly, a device area floor plan which is drawn on the analysis computer according to the distance proportion by utilizing special drawing software is displayed on the device area floor plan which corresponds to the device area floor plan displayed on the screen of the data analysis computer according to the current, potential distribution diagram and calculation data which are required to be displayed by the computer;
the data analysis computer can also be connected with a control server of the enterprise dispatching center according to the requirement so as to send the test process and the data to the control server of the enterprise dispatching center;
acquiring potential gradient differences generated by all high-low voltage equipment grounding wires on a large grounding network in operation, acquiring current values on the low-voltage cable shielding grounding wires, and sending the acquired values to an equipment plane layout corresponding to the equipment; the quality of the grounding grid is qualified, and the potential on the grounding wires of all the equipment is zero; the ground line of the equipment which generates the potential gradient difference is certainly problematic.
Thirdly, applying a current signal to the grounding grid by using the signal source device, and acquiring voltage and current distribution maps of all high-voltage and low-voltage equipment on the large-scale grounding grid; the computer calculates the impedance value and the equivalent sectional area between the grounding wire and the grounding network of each high-voltage device according to the output data of the signal source device and the current and voltage distribution diagram data of the grounding network; accurately positioning dangerous points of the large-scale grounding grid;
depending on the parameters of the output of the signal source and the voltage and distance between the two points of the device A, B, voltage/distance is the voltage per meter. Carrying in fault system voltage and current by utilizing the ratio of voltage between two points and the U/L distance, and calculating contact voltage generated by a device shell, step voltage generated by the ground around the device and transfer voltage when the system has a ground fault;
measuring potential gradient difference in equipment protection grounding wires and current values in shielding wires, and calculating interference degree of a large-scale grounding grid to a relay protection and automatic device, a telecontrol communication system and a signal system when the large-scale grounding grid passes through working current and single-phase grounding short-circuit fault current, and damage to low-voltage equipment insulation; and accurately displaying the interference signal source on a computer screen and displaying the accurate position of the fault point of the grounding system.
Fifthly, the computer accurately and automatically draws various technical index curve graphs according to the measured and calculated data to prompt that the existing critical defects, serious defects, general defects and qualified equipment of the equipment are stored in the curve graphs and bar graphs
Sixthly, verification: connecting a temporary short circuit line between equipment grounding wires at two ends of the grounding grid with faults at the position where the potential gradient difference mutation is generated; and (3) checking the elimination of the potential gradient difference between the two devices, proving that a fault exists between the two points of the grounding grid, and then installing a permanent grounding grid line at the position where the temporary short-circuit line is laid to eliminate the fault.
The invention relates to a detection system of a detection method of a large-scale comprehensive grounding system (network), which is characterized in that:
the device comprises a data analysis computer, a signal source device and more than two data acquisition devices, wherein the number of the used data acquisition devices is determined according to the number of the equipment to be tested, each data acquisition device is provided with 16 current and voltage measurement terminals, the measurement lines are respectively connected to a grounding wire of the equipment to be tested, each data acquisition device is provided with a signal output interface and a signal input interface, and the data connection of the data acquisition devices is transmitted to the data analysis computer; the signal source device provides a direct current working power supply for the data acquisition device through a data line; the signal output interface of the signal source device is connected to the data analysis computer; the N end of the zero potential reference output port of the signal source device is directly fixed to a certain point of the grounding grid, and the L end of the current output port of the signal source device is connected to a grounding wire of high-voltage equipment to be tested.
The invention can also connect the collected data of the data collecting device to the signal source through the signal output interface, and send the collected data to the data analysis computer through the 485 data line connection arranged in the signal source;
the signal source device includes: the system comprises a wireless communication module, a local control circuit, an isolation transformer, a direct current rectification circuit, a signal source input and output data acquisition module and an A/D signal analog-to-digital conversion module; the access power supply is respectively connected to the wireless communication module, the signal digital-to-analog conversion module and the signal input interface through the direct current rectifying circuit so as to provide corresponding direct current power supplies; the local control circuit controls the switch through a button to control the isolation transformer to output an electric signal;
the signal source input and output data and the acquisition module acquire the input and output data of the isolation transformer and send the data to the wireless communication module through the A/D signal analog-to-digital conversion module or directly send the data to the data analysis computer through the output terminal of the signal source. One end of a low-voltage heavy-current signal terminal output by the signal source isolation transformer is connected to a preset zero potential reference point of the grounding grid, and the other end of the low-voltage heavy-current signal terminal is connected to a high-voltage equipment grounding wire to be tested of the large-scale grounding grid; the isolation transformer can isolate the high voltage of 50HZ \220V of the system from the station power utilization system through the transformer and change the high voltage into a safe low voltage signal of the test grounding network.
The data acquisition device includes: the system comprises a wiring self-checking circuit, a voltage and current acquisition circuit and an analog-to-digital conversion and data storage module; the voltage and current acquisition terminal is connected to the voltage and current acquisition circuit through the wiring self-checking circuit, the output of the voltage circuit acquisition circuit is connected to the input end of the analog-to-digital conversion and data storage module, and the output of the analog-to-digital conversion and data storage module is connected to the data analysis computer; the direct current output by the signal source device respectively provides power for the wiring self-checking circuit, the voltage and current acquisition circuit and the analog-to-digital conversion and data storage module.
The wiring self-checking circuit of the invention comprises: the voltage signal is applied between a zero potential reference point ground wire and a grounding grid test wire through a test wire test button on a voltage test wire, and the voltage test wire is connected with a test lamp.
The invention has the beneficial effects that:
(1) and the electric conduction condition and the grounding resistance of a grounding network of a power plant, a transformer substation, a traction substation and a signal building are accurately calculated and displayed. However, the two technical indexes are qualified, and the comprehensive grounding system cannot be qualified at all.
In items 2-8 below, the key technical parameters of the grounding grid cannot be obtained by the detection equipment and the technical measurement method specified in the guide rules.
(2) The fault current conduction capability, the thermal stability value and the lightning current releasing capability of a power plant, a transformer substation and a traction substation grounding grid in operation cannot be obtained by a conventional measuring method.
(3) When a power plant, a transformer substation and a traction substation grounding grid are subjected to grounding short-circuit current and lightning attack, critical data which endanger personal safety and equipment safety, such as potential gradient difference generated between grounding wires of high-low voltage equipment, step voltage generated in an equipment area, equipment contact voltage, transfer potential and the like, are difficult to obtain by the conventional grounding grid detection equipment and technology.
(4) The conventional grounding grid detection equipment and technology cannot accurately position fault points and calculate various technical parameters of the grounding grid fault points, so that effective anti-accident measures cannot be made.
(5) The potential and current distribution diagram of the large-scale grounding grid, the corrosion degree and the accurate position of the grounding grid can be visually displayed on a computer screen, and the equivalent impedance value and the equivalent sectional area of each grounding wire of high-voltage electrical equipment in operation can be calculated.
(6) And calculating various technical parameters in the operation of the large-scale grounding grid according to the current and potential distribution diagram of the grounding grid, and analyzing and calculating the failure reason of the lightning arrester. When the system has a ground fault, the threat degree of insulation of low-voltage equipment such as microelectronic communication equipment, relay protection devices, signal control and the like is analyzed, and the influence of the defects of the grounding grid on the operation refusing and misoperation of microcomputer protection of power plants, substations and traction substations and the influence on safe driving of the electrified railway are accurately analyzed.
(7) The occurrence source of the interference signal system fault caused by the defects of the grounding device of the electrical equipment along the electrified railway can be visually displayed on a computer screen.
(8) The ground fault point of the electrical equipment along the power plant, the transformer substation, the traction substation, the signal building and the railway can be accurately positioned without excavating and checking a ground network.
The method of the invention has the following functions: the current and potential distribution diagram of the large-scale grounding grid can be visually displayed on a screen by utilizing a computer to measure the comprehensive grounding grid system, and various technical parameters measured according to the regulations of the guide rules can be accurately calculated according to the potential distribution diagram: the electrical integrity, the grounding impedance, the field surface potential gradient difference, the contact potential difference, the step potential difference, the transfer potential, the equivalent sectional area of each high-voltage equipment grounding wire after being corroded and various key data of a fault point of the grounding device accurately position the position of the fault point. And establishing a storage computer detection large-scale grounding network database.
The speed of measuring and calculating the data of the grounding grid by the computer is more than tens of times of the speed of the conventional measuring method, and the precision of detecting and calculating each item of data of the grounding grid by the computer is incomparable with the conventional detection technology.
The functions of the device are summarized as follows:
1. the computer detects large-scale grounding networks of power plants, transformer substations, traction substations and signal buildings, detects the grounding of control signals along the electrified railway, absolutely does not influence the safe operation of the system, does not need to take safety measures, and can carry out the grounding network detection work all the year round at any time. And a test wire with the length of thousands of meters does not need to be laid outside the plant.
2. Besides calculating various key data of the grounding grid, the corrosion degree of the grounding grid can be measured, compared and calculated, the equivalent sectional area of the grounding wire of the equipment can be calculated, and the heat stability value of the grounding device and other key technical parameters can be calculated.
3. The influence of the potential gradient difference of the grounding grid on the action voltage of the lightning arrester, the interference condition on a relay protection automatic device and the degree of damage to the automatic control, telemechanical, communication, direct current system and low-voltage equipment insulation of a power plant, a transformer substation and a traction substation are accurately analyzed.
4. The corrosion degree of the large-scale grounding grid can be determined without excavation and inspection, the accurate position with defects is hidden, various technical data of the fault point of the grounding grid are calculated, the defects of the grounding grid are eliminated in time, and the occurrence of major equipment burning accidents caused by the defects of the grounding grid is avoided.
5. According to the current and potential distribution diagram, the interference source influencing the control and signal system can be accurately found.
Drawings
Fig. 1 is a schematic diagram of a detection method of a large-scale integrated grounding system according to an embodiment of the present invention;
fig. 2 is a schematic diagram illustrating a verification method of a large-scale integrated grounding system according to an embodiment of the present invention;
FIG. 3 is a schematic block circuit diagram of a detection system of a large-scale integrated grounding system according to an embodiment of the present invention;
FIG. 4 is a schematic block diagram of a detection system of a large-scale integrated grounding system according to an embodiment of the present invention;
FIG. 5 is a schematic block diagram of a data acquisition device of a detection system of a large-scale integrated grounding system according to an embodiment of the present invention;
FIG. 6 is a flowchart illustrating a computer operation in a detection system of a large-scale integrated grounding system according to an embodiment of the present invention;
FIG. 7 is a diagram illustrating a detection method according to another embodiment of the present invention.
Detailed Description
As shown in the attached fig. 1 and 2, the invention relates to a detection method of a large-scale integrated grounding system (network), which comprises the following steps: firstly, preparation before testing: firstly, connecting a ground wire of high-voltage and low-voltage equipment to be tested in a large-scale comprehensive grounding system to a test wire interface of a data acquisition device, transmitting acquired data to a data analysis computer by the data acquisition device, and adding a plurality of data acquisition devices according to the number of the test equipment; one port of current output on the signal source device is fixedly connected to one point on a grounding network as a reference zero potential reference point, the other output port of the signal source is connected to a grounding wire of high-voltage equipment to be tested according to the requirement, the data of the signal source is also required to be connected and transmitted to a data analysis computer, and the signal source device provides power for each data acquisition device;
for convenient connection, a plurality of data acquisition devices can be connected in series through 485 data acquisition lines and then connected to a data input port of a signal source device, and then connected to a data analysis computer through an output port of the signal source device;
secondly, a device area floor plan which is drawn on the analysis computer according to the distance proportion by utilizing special drawing software is displayed on the device area floor plan which corresponds to the device area floor plan displayed on the screen of the data analysis computer according to the current, potential distribution diagram and calculation data which are required to be displayed by the computer;
the data analysis computer can also be connected with a control server of the enterprise dispatching center according to the requirement so as to send the test process and the data to the control server of the enterprise dispatching center;
acquiring potential gradient differences generated by all high-low voltage equipment grounding wires on a large grounding network in operation, acquiring current values on the low-voltage cable shielding grounding wires, and sending the acquired values to an equipment plane layout corresponding to the equipment; the quality of the grounding grid is qualified, and the potential on the grounding wires of all the equipment is zero; the ground line of the equipment which generates the potential gradient difference is certainly problematic.
Thirdly, applying a current signal to the grounding grid by using the signal source device, and acquiring voltage and current distribution maps of all high-voltage and low-voltage equipment on the large-scale grounding grid; the computer calculates the impedance value and the equivalent sectional area between the grounding wire and the grounding network of each high-voltage device according to the output data of the signal source device and the current and voltage distribution diagram data of the grounding network; accurately positioning dangerous points of the large-scale grounding grid;
depending on the parameters of the output of the signal source and the voltage and distance between the two points of the device A, B, voltage/distance is the voltage per meter. Carrying in fault system voltage and current by utilizing the ratio of voltage between two points and the U/L distance, and calculating contact voltage generated by a device shell, step voltage generated by the ground around the device and transfer voltage when the system has a ground fault;
measuring potential gradient difference in equipment protection grounding wires and current values in shielding wires, and calculating interference degree of a large-scale grounding grid to a relay protection and automatic device, a telecontrol communication system and a signal system when the large-scale grounding grid passes through working current and single-phase grounding short-circuit fault current, and damage to low-voltage equipment insulation; and accurately displaying the interference signal source on a computer screen and displaying the accurate position of the fault point of the grounding system.
Fifthly, the computer accurately and automatically draws various technical index curve graphs according to the measured and calculated data to prompt that the existing critical defects, serious defects, general defects and qualified equipment of the equipment are stored in the curve graphs and bar graphs
Sixthly, verification: connecting a temporary short circuit line between equipment grounding wires at two ends of the grounding grid with faults at the position where the potential gradient difference mutation is generated; and (3) checking the elimination of the potential gradient difference between the two devices, proving that a fault exists between the two points of the grounding grid, and then installing a permanent grounding grid line at the position where the temporary short-circuit line is laid to eliminate the fault.
As shown in the attached figures 1 and 2: the actual testing wiring steps and the operation process of the invention can be as follows:
1. the N end of the signal source for outputting the electric signal is fixedly connected with the neutral point grounding end of the main transformer in operation and serves as a zero potential reference point. And the L end is connected according to the test requirement item.
2. And the 485 data line of the computer is connected with the signal output end of the signal source.
3. The special drawing software in the computer is utilized to draw the layout of high and low voltage equipment, building construction and channel floor in the equipment area according to the distance proportion, so that the step voltage and the transfer voltage in the equipment area can be accurately calculated.
4. When the data of the computer is difficult to read under outdoor strong light, a remote control operation program of the computer is started, and the grounding grid detection amount work is carried out indoors or in a place with proper light. The worker can choose one of the operation modes.
5. In the super-huge grounding network, a data acquisition device is arranged in each high-low voltage equipment concentration region, signal output, signal input and ports of 1-N data acquisition devices are connected in series by using RS485 data transmission lines, and a signal output end of a starting end data acquisition device is connected to a signal input port of a signal source.
6. The panel jacks of the data acquisition device are sequentially and respectively connected to the protective grounding wire of the high-voltage equipment by using the test wires.
7. And starting a signal source control button, and checking that a working indicator lamp on a panel of the data acquisition device is lightened to show that the data transmission line is in good contact. The work indicator light flickers to indicate that the data acquisition device is transmitting data.
8. When a wiring good test button of the data acquisition device is pressed, the 16 red lamps are all lightened to indicate that the test line is in good contact, and the light is not lightened to indicate that the voltage acquisition line is in poor contact, or high-voltage equipment of the voltage acquisition device is not grounded, or higher voltage is generated.
9. When a signal source starting button is pressed, the working state indicator lamp begins to flicker, and the display data of the checking meter is the same as the display data of the computer display signal source.
10. When the stop button of the signal source is pressed, the status indicator lamp is turned off, and the output voltage of the signal source and the ammeter return to zero.
11. And pressing a wiring test button of the data acquisition device, and checking that the 1-16 lines of wiring correct indicator lamps are all lighted.
12. The signal source can be controlled locally, or can be remotely controlled by a computer to operate a large-scale grounding grid detection program. The worker can select one of the operation modes at will.
When the impedance values of the 5 high-voltage equipment grounding wires R1-R4 marked on FIG. 2 meet the design requirements, the potential differences among the grounding wires should be zero. When the grounding wire of the equipment is seriously corroded or broken, the potential difference is generated between the grounding wire of the high-voltage equipment and the grounding wire of the adjacent equipment. The larger the potential difference, the more severe the fault property.
In fig. 2, R2 between the 2# device and the 3# device increases in resistance, and a potential difference occurs, indicating that the ground line between the two devices has failed or broken.
The detection system according to the embodiment of the present invention shown in fig. 3, 4, 5, and 6 includes a data analysis computer, a signal source device, and more than two data acquisition devices, wherein the number of the data acquisition devices is determined according to the number of the devices to be tested, and the voltage and current wiring ports of the data acquisition devices are respectively connected to the ground wire terminal of the devices to be tested. And the data output interface of the data acquisition device is connected to the signal input end of the signal source. The data collected by the data acquisition device and the working data of the signal source device are sent to the data analysis computer through a 485 data line.
The signal source device is internally provided with a wireless communication module which sends data acquired by the signal source and the data acquisition device to a data analysis computer, the data analysis computer is in bidirectional connection with the signal source device, the computer can remotely control a working program of the signal source and simultaneously receive the acquired data of the signal source and the data acquisition device, and a direct current power supply output by the signal source device provides a working power supply for a plurality of data acquisition devices through a signal communication cable and also provides a reference zero potential reference point for the signal source device and the data acquisition device. The reference point is fixedly connected to a main transformer neutral point on the grounding of the equipment to be detected or a grounding wire of certain equipment or a ground beyond 100 meters of a power plant, a transformer substation and a traction substation;
the signal source device includes: the system comprises a wireless communication module, a local control circuit, an isolation transformer, a direct current rectifying circuit, a signal source input and output data acquisition module and a signal analog-to-digital conversion circuit; the device direct current power supply provides corresponding direct current power supply for the wireless communication module, the signal analog-to-digital conversion circuit and the data acquisition device through the signal input interface through the direct current rectification circuit;
the local control on-off button controls an isolation transformer in a signal source, and an input and output data acquisition module of the isolation transformer is connected to the wireless communication module through a signal analog-to-digital conversion circuit, and transmits data to a data analysis computer through a remote control antenna or is directly connected to a data input interface of the data analysis computer through a 485 data line. The output N end of an isolation transformer in the signal source is connected to a set zero potential reference point, and the output L end of the isolation transformer is connected to a high-voltage equipment grounding wire in a large grounding network to be tested; a safe low voltage signal is applied to the large earth grid. In the signal source device in practical use of the invention: in the signal source device: the wireless communication module can adopt an external wireless data transmission module which has large transmitting current and strong penetrating power and can resist a strong magnetic field and is of a KYL-3201 model.
The local control circuit model adopts a LA phi 19-AJS-E conventional button control circuit: the circuit consists of an FZ opening button, an HZ closing button and a CJT1-10-40A contactor. The control circuit: the starting circuit is characterized in that a 220V live wire presses a normally open contact of an HZ closing button through a normally closed contact of an FZ opening button, an HQ closing coil of a contactor is electrified, a main contact of the contactor is closed, an isolation transformer power supply is connected, meanwhile, a normally open auxiliary contact of the contactor is closed, the electrified state of the closing coil is kept, and the isolation transformer starts to work continuously; and when the FZ opening button is pressed down, the starting coil of the contactor loses power, the normally open auxiliary contact of the contactor is disconnected, the coil of the contactor loses power, and the contactor cuts off the power supply of the isolation transformer. And stopping sending the electric signal to the grounding grid.
The signal source collects input and output data of the isolation transformer by using a USB-2408-2A0 data acquisition card, sends the data of the isolation transformer to an ADC76-16 bit A/D converter, and quickly converts the data of the isolation transformer by the high-resolution A/D converter, and sends the data to a data analysis computer by a signal source signal output port and a 485 data line. And the data acquired by the grounding grid data acquisition device is transmitted to the data analysis computer through the input interface and the output interface of the signal source device. Or the data is transmitted to the data analysis computer through the A/D conversion module of the signal source and the antenna of the wireless communication module.
The acquisition device acquires voltage and current values on a ground wire of high-low voltage equipment by using an MR-AI08 voltage and current acquisition circuit module, processes the voltage and current values through a CS5532-24 bit A/D analog/digital conversion chip and a 89C51 main control chip program data, controls the acquisition of MR-AI08 voltage and current data through software, stores the data into a register, and simultaneously sends the acquired data to a computer. According to the increase of the data of the grounding grid equipment, a plurality of devices can acquire the data at the same time.
As shown in fig. 5, the data acquisition apparatus includes: the system comprises a wiring self-checking circuit, a voltage and current acquisition circuit and an analog-to-digital conversion and data storage module; as shown in fig. 5, the dc power supply outputted by the signal source is a working power supply provided for the data acquisition device. The panel of the data acquisition device is respectively provided with 16 jacks of a voltage measuring terminal and a current measuring terminal. And a display lamp for verifying good wiring is arranged at the position corresponding to the port of the measuring wire, and when the button for checking the wiring is pressed down, the corresponding red display lamp is lightened. The test wire connected with the voltage and current acquisition terminal acquires the voltage and current values on the ground wire of the high-low voltage equipment through the MR-AI08 voltage and current acquisition module circuit. And the data is transmitted to a CS5532-24 bit A/D analog/digital converter chip, data processing is carried out through a main control chip program with the model of 89C51, and a data transmission indicator lamp flickers in the data processing and storing process. The data collected by the device is connected to the computer in the wave front through the signal output port and the RS485 data line for data processing, and ninthly, another data collection device collects the data simultaneously according to the increase of the data of the grounding network equipment. The signal output by said device is transmitted to the computer in the R (R) through RS485 data line for data processing. The wiring self-checking circuit: the voltage signal is applied between a zero potential reference point ground wire and a grounding grid test wire through a test wire test button on a voltage test wire, and the voltage test wire is connected with a test lamp.
The working process of the invention is as follows:
the signal source working program (1) can be connected with a 220V power supply, and (11) a 220V external power supply is connected with a notebook alternating current 220V power supply. The 220V power supply is rectified into direct current through the rectifier, and the direct current power supply is provided for the transformer output and input data acquisition device, the A/D analog-to-digital converter and the 1-N data acquisition device. (2) Pressing a main power supply control button, enabling the transformer to enter a hot standby state, and starting a button to stop the button to control the transformer to send an electric signal to a grounding grid; the electric signal is sent to a grounding grid; (3) when the antenna and the notebook computer remotely control the detection system, real-time data in the signal source is received through the antenna, and a start and stop working command of the signal source is sent through the antenna.
(II) working procedures of the data acquisition device: the ground wires of the tested equipment are connected to the wiring terminals of the data acquisition device in sequence, the red working indicator lights flicker when the device acquires and transmits data, and when the wiring good verification button is pressed, the indicator lights corresponding to the wiring terminals should be lightened to indicate that the wiring is correct and good. The signal output interface and the signal input interface are used for transmitting the direct current power supply and simultaneously converting the data of the acquisition signal source and the data acquisition device into 485 signals to be sent to the computer.
(III) the flow of the computer control system: the working states of stopping and starting of the signal source are remotely controlled by a computer of the wireless communication system; the computer receives various data such as voltage and current output by the data acquisition device and the signal source and simultaneously sends work instruction data to the data acquisition device and the signal source; displaying the acquired data on corresponding equipment positions to draw a wiring plane layout diagram of the comprehensive grounding system, and calculating various indexes of the grounding grid by a computer according to a theoretical formula; drawing a curve graph, a bar graph and a summary table according to each data result; storing historical measurement data, archiving, and making a safety quality evaluation report of the comprehensive grounding system; and finally, printing a test report.
Fig. 7 is a block diagram of interference and grounding measurement for protection, control and signal cable shielding in power plants, substations, traction substations of electrified railways and command centers of signal buildings.
FIG. 7 illustrates: the grounding network data acquisition device acquires voltage values between various low-voltage control and signal cable grounding busbars and the ground of a power plant, a transformer substation, an electrified railway, a signal control room and the like, and acquires current values on a cable shielding wire. And accurately positioning the position of the shielding ground fault point of the equipment.
Claims (5)
1. A detection method of a large-scale comprehensive grounding system is characterized by comprising the following steps:
(I), preparation before testing:
firstly, connecting a ground wire of high-voltage and low-voltage equipment to be tested in a large-scale comprehensive grounding system to a test wire interface of a data acquisition device, transmitting acquired data to a data analysis computer by the data acquisition device, and adding a plurality of data acquisition devices according to the number of the test equipment; one port of current output on the signal source device is fixedly connected to one point on a grounding network as a reference zero potential reference point, the other output port of the signal source is connected to a grounding wire of high-voltage equipment to be tested according to the requirement, the data of the signal source is also required to be connected and transmitted to a data analysis computer, and the signal source device provides power for each data acquisition device;
secondly, a device area floor plan which is drawn on the analysis computer according to the distance proportion by utilizing special drawing software is displayed on the device area floor plan which corresponds to the device area floor plan displayed on the screen of the data analysis computer according to the current, potential distribution diagram and calculation data which are required to be displayed by the computer;
acquiring potential gradient differences generated by all high-low voltage equipment grounding wires on a large grounding network in operation, acquiring current values on the low-voltage cable shielding grounding wires, and sending the acquired values to an equipment plane layout diagram corresponding to the equipment; the quality of the grounding grid is qualified, and the potential on the grounding wires of all the equipment is zero; the equipment grounding wire generating potential gradient difference is certain to have problems;
thirdly, applying a current signal to the grounding network by using a signal source device, and acquiring voltage and current distribution maps of all high-voltage and low-voltage equipment on the large-scale grounding network; the computer calculates the impedance value and the equivalent sectional area between the grounding wire and the grounding network of each high-voltage device according to the output data of the signal source device and the current and voltage distribution diagram data of the grounding network; accurately positioning dangerous points of the large-scale grounding grid;
according to the parameters of the output of the signal source and the voltage and distance between two points of the device A, B, the voltage/distance is the voltage between each meter;
carrying in fault system voltage and current by utilizing the ratio of voltage between two points and the U/L distance, and calculating contact voltage generated by a device shell, step voltage generated by the ground around the device and transfer voltage when the system has a ground fault;
measuring potential gradient difference in equipment protection grounding wires and current values in shielding wires, and calculating interference degree of a large-scale grounding grid to a relay protection and automatic device, a telemechanical communication system and a signal system when the large-scale grounding grid passes through working current and single-phase grounding short-circuit fault current occurs in the system, and damage to low-voltage equipment insulation; accurately displaying an interference signal source on a computer screen and displaying the accurate position of a fault point of the grounding system;
the computer accurately and automatically draws various technical index curve graphs according to the measured and calculated data, and prompts the existing critical defects, serious defects, general defects and qualified equipment of the equipment, and the curve graphs and bar-shaped graphs are filed;
(VI) verifying: connecting a temporary short circuit line between equipment grounding wires at two ends of the grounding grid with faults at the position where the potential gradient difference mutation is generated; and (3) checking the elimination of the potential gradient difference between the two devices, proving that a fault exists between the two points of the grounding grid, and then installing a permanent grounding grid line at the position where the temporary short-circuit line is laid to eliminate the fault.
2. The method for detecting the large-scale comprehensive grounding system according to claim 1, characterized in that: in order to facilitate connection, the detection method can connect a plurality of data acquisition devices in series through 485 data acquisition lines, then connect the data acquisition devices to a data input port of a signal source device, and connect the data input port of the signal source device to a data analysis computer through an output port of the signal source device.
3. The method for detecting the large-scale comprehensive grounding system according to claim 1, characterized in that: the data analysis computer can also be connected with a control server of the enterprise dispatching center according to the requirement so as to transmit the test process and the data to the control server of the enterprise dispatching center.
4. The detection system of the detection method of the large-scale integrated grounding system according to claim 1, wherein:
the detection system comprises a data analysis computer, a signal source device and more than two data acquisition devices, wherein the number of the used data acquisition devices is determined according to the number of the equipment to be detected, each data acquisition device is provided with 16 current and voltage measurement terminals, the measurement lines are respectively connected to a grounding wire of the equipment to be detected, each data acquisition device is provided with a signal output interface and a signal input interface, the data output interface of the data acquisition device is connected to the signal input interface of the signal source through a data line, and then the signal output interface of the signal source is connected to the data analysis computer through a 485 data line; the signal source device provides a direct current working power supply for the data acquisition device through a data line; the signal output interface of the signal source device is connected to the data analysis computer; the N end of a zero potential reference output port of the signal source device is directly fixed to a certain point of the grounding grid, and the L end of a current output port of the signal source device is connected to a grounding wire of high-voltage equipment to be tested;
the signal source device includes: the system comprises a wireless communication module, a local control circuit, an isolation transformer, a direct current rectification circuit, a signal source input and output data acquisition module and an A/D signal analog-to-digital conversion module; the access power supply is respectively connected to the wireless communication module, the signal analog-to-digital conversion module and the signal input interface through the direct current rectification circuit so as to provide corresponding direct current power supplies; the local control circuit controls the switch through a button to control the isolation transformer to output an electric signal;
the signal source data acquisition module acquires input and output data of the isolation transformer and sends the input and output data to the wireless communication module through the A/D signal analog-to-digital conversion module or directly sends the input and output data to the data analysis computer through an output terminal of a signal source;
one end of a low-voltage heavy-current signal terminal output by the signal source isolation transformer is connected to a preset zero potential reference point of the grounding grid, and the other end of the low-voltage heavy-current signal terminal is connected to a high-voltage equipment grounding wire to be tested of the large-scale grounding grid;
the data acquisition device includes: the system comprises a wiring self-checking circuit, a voltage and current acquisition circuit and an analog-to-digital conversion and data storage module; the voltage and current acquisition terminal is communicated with a grounding grid through a wiring self-checking circuit button, the circuit is connected with a signal lamp in series, the lamp is on to indicate that the connection of the test wire is good, the output of the voltage circuit acquisition circuit is connected to the input end of the analog-to-digital conversion and data storage module, and the output of the analog-to-digital conversion and data storage module is connected to the data analysis computer; the direct current output by the signal source device respectively provides power for the wiring self-checking circuit, the voltage and current acquisition circuit and the analog-to-digital conversion and data storage module.
5. The detection system of the detection method of the large-scale comprehensive grounding system according to claim 4, characterized in that: the data acquisition device is connected to the signal input interface of the signal source through the signal output interface, and transmits the acquired data to the data analysis computer through the signal source output port of the signal source.
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