Air intermittent arc monitoring system and method based on multi-data fusion

Abstract

The invention discloses an air intermittent arc monitoring system and method based on multi-data fusion, and belongs to the technical field of power transmission line fault recognition. The system comprises a data acquisition module, a data preprocessing module, a data analysis module and an output module. The method comprises the following steps: arranging a plurality of infrared temperature measuring devices and electrical quantity measuring devices on the overhead line, acquiring infrared monitoring data and electrical quantity measuring data, preprocessing the infrared monitoring data and the electrical quantity measuring data, converting air radiation energy data in the infrared monitoring data into air temperature, and calculating arc resistance according to voltage and current data in the electrical quantity measuring data; solving the relationship between the air temperature and the air conductivity and an arc extinguishing threshold value, and judging the arc state by combining the air temperature and the arc resistance; and outputting an arc state judgment result. According to the method, the arc temperature and the arc resistance are combined, the electric and thermal characteristics of the arc as plasma are considered, and the accuracy of distribution network air intermittent arc identification and monitoring is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power transmission line fault identification, and in particular relates to an air intermittent arc monitoring system and method based on multi-data fusion. Background Art

[0002] The arc grounding of the single-phase distribution network is difficult to identify. The unstable intermittent arc can be extinguished and reignited many times, resulting in energy redistribution between the three phases, causing high-frequency oscillation overvoltage, and the overvoltage amplitude of the non-fault phase can be up to 3.5 times the rated voltage. Overvoltage will threaten the insulation of electrical equipment, and may directly damage the insulation of weak links and cause breakdown, thereby causing grounding faults, and even further developing into phase-to-phase short circuits, or exciting ferromagnetic resonance to expand faults, damage equipment, cause fires, and cause power outages.

[0003] Prior art document 1 (CN111965500A) discloses a test device and method suitable for measuring air arc, which mainly includes a resistor-capacitor voltage divider, a current sensor, a signal acquisition device, a signal conditioning circuit, an A / D conversion circuit, a single-chip microcomputer control chip, an RS232 communication module, and an arc temperature measurement system. The device can conduct a large number of clear and convenient tests on the arc self-extinguishing critical current, measure the test waveform, study the arc self-extinguishing characteristics, and measure and analyze the arc temperature. The shortcoming of the prior art is that the prior art is only suitable for application in test scenarios, such as artificial single-phase grounding tests, and is not suitable for actual distribution lines. Summary of the invention

[0004] In order to solve the deficiencies in the prior art, the present invention provides an air intermittent arc monitoring method based on multi-data fusion. In view of the fact that intermittent arcs in the existing distribution network are difficult to identify, a method for air intermittent arc monitoring based on infrared temperature measurement and multi-data fusion of arc voltage, current, etc. is proposed.

[0005] The present invention adopts the following technical solution.

[0006] The first aspect of the present invention provides an air intermittent arc monitoring system based on multi-data fusion, comprising: a data acquisition module, a data preprocessing module, a data analysis module and an output module;

[0007] The data acquisition module includes an infrared temperature measuring device and an electrical quantity measuring device, which are used to collect the air radiation energy on the overhead line and the electrical quantity of the overhead line;

[0008] The data preprocessing module is connected to the data acquisition module and is used to solve the electrical quantity of the overhead line to obtain the arc resistance, and to convert the air radiation energy on the overhead line into air temperature. The data preprocessing module includes a wireless transmission module, which transmits the arc resistance and air temperature to the data analysis module via the wireless transmission module;

[0009] The data analysis module is connected to the wireless transmission module in the data preprocessing module and is used to make arc judgment based on the air temperature and electrical quantity obtained by the data acquisition module;

[0010] The output module is connected to the data analysis module, and outputs the judgment result of arc occurrence obtained by the data analysis module, so as to realize the intermittent arc monitoring in air under multi-data fusion.

[0011] Preferably, in the data acquisition module, the infrared measuring device and the electrical quantity measuring device are integrated together, and an infrared temperature measuring device and an electrical quantity measuring device are arranged on all pole towers on the overhead lines. The infrared measuring device collects infrared monitoring data, and the electrical quantity measuring device includes a voltage sensor and a current sensor for collecting voltage and current data of the overhead lines.

[0012] Preferably, in the data analysis module, when the air temperature obtained by the data preprocessing module is below 3000K and the air arc resistance is higher than the arc extinction threshold, it is determined that the arc is extinguished;

[0013] When the air temperature obtained by the data preprocessing module is above 6000K and the air arc resistance is lower than the arc extinction threshold, it is judged that the arc is burning.

[0014] A second aspect of the present invention provides an air intermittent arc monitoring method based on multi-data fusion, which is used to operate the air intermittent arc monitoring system based on multi-data fusion, comprising:

[0015] Step 1: An infrared temperature measuring device and an electrical quantity measuring device are installed on all the towers on the overhead line to collect infrared monitoring data and electrical quantity measurement data;

[0016] Step 2: pre-process the infrared monitoring data and electrical quantity measurement data collected in step 1, convert the air radiation energy data in the infrared monitoring data into air temperature, calculate the arc resistance according to the voltage and current data in the electrical quantity measurement data, and obtain the air temperature and arc resistance;

[0017] Step 3: According to the air temperature and arc resistance obtained in step 2, the relationship between air temperature and air conductivity and the arc extinction threshold are solved respectively, and the arc state is judged by combining the air temperature and arc resistance;

[0018] Step 4: Output the arc state judgment result obtained in step 3 to realize air intermittent arc monitoring under multi-data fusion.

[0019] Preferably, in step 1, the sensor in the infrared temperature measuring device converts the captured infrared signal on the overhead line into an electrical signal, the receiver in the infrared temperature measuring device converts the electrical signal into a digital signal, and amplifies and filters the digital signal to obtain infrared monitoring data.

[0020] Preferably, in step 2, the air radiation energy on the overhead line in the infrared monitoring data measured by the infrared temperature measuring device is converted into air temperature, which is expressed by the following formula:

[0021]

[0022] in,

[0023] P b is the air radiation power,

[0024] λ is the wavelength,

[0025] c1 and c2 are radiation constants,

[0026] T is the air temperature.

[0027] Preferably, in step 2, the phase voltage of the overhead line is a sinusoidally varying AC power supply, the current is 0, the line single-phase arc is grounded, the air gap is broken down, and the arc resistance at which the arc is grounded is calculated using the ratio between the voltage and the current.

[0028] Preferably, in step 3, the relationship between air conductivity and temperature is expressed by the following formula:

[0029]

[0030] In the formula,

[0031] T is the air temperature;

[0032] σ is the air conductivity.

[0033] Preferably, in step 3, the arc extinction threshold is obtained by an artificial single-phase arc grounding test. During the artificial single-phase arc grounding test, the current is controlled and the generated arc is monitored. When the measured arc resistance rises to a set threshold, the arc cannot burn, and the set threshold is used as the arc extinction threshold.

[0034] Preferably, in step 3, the measured air temperature and arc resistance are summarized in the substation control cabinet. When a single-phase grounding arc fault occurs, the air temperature and arc resistance data obtained by the infrared temperature measuring devices placed on all the towers of the overhead lines are determined by the substation control cabinet. When the air temperature is below 3000K and the air arc resistance is higher than the arc extinction threshold, it is determined that the arc is extinguished.

[0035] When the air temperature is above 6000K and the air arc resistance is lower than the arc extinction threshold, the arc is judged to be burning. The substation control cabinet displays the arc status of all towers and locates the arc.

[0036] The beneficial effect of the present invention is that, compared with the prior art, the present invention combines arc temperature and arc resistance to monitor the occurrence of intermittent arcs in the distribution network, fully considering the electrical and thermal characteristics of the arc as a plasma. The monitoring method proposed in the present invention can be directly applied to actual distribution lines, and the accuracy of identifying and monitoring intermittent arcs in the air of the distribution network is greatly improved, which is of great significance to the safe and stable operation of the distribution network. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a module diagram of the air intermittent arc monitoring system based on multi-data fusion in the present invention;

[0038] Figure 2 It is a flow chart of the air intermittent arc monitoring method based on multi-data fusion in the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only part of the embodiments of the present invention, not all of them. Based on the spirit of the present invention, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of the present invention.

[0040] In order to solve the deficiencies in the prior art, the present invention provides an air intermittent arc monitoring method based on multi-data fusion. In view of the fact that intermittent arcs in the existing distribution network are difficult to identify, a method for air intermittent arc monitoring based on infrared temperature measurement and multi-data fusion of arc voltage, current, etc. is proposed.

[0041] The present invention adopts the following technical scheme.

[0042] like Figure 1 As shown, embodiment 1 of the present invention proposes an air intermittent arc monitoring system based on multi-data fusion, including: a data acquisition module, a data preprocessing module, a data analysis module and an output module.

[0043] Data acquisition module, used to collect air radiation energy on overhead lines and electrical quantities of overhead lines;

[0044] The data acquisition module includes: infrared temperature measuring device and electrical quantity measuring device;

[0045] Among them, the infrared measuring device is integrated with the electrical quantity measuring device. An infrared temperature measuring device and an electrical quantity measuring device are installed on all towers on the overhead lines to collect infrared monitoring data and voltage and current data respectively.

[0046] The data preprocessing module is connected to the data acquisition module and is used to solve the voltage and current data to obtain the arc resistance of the overhead line, and to perform radiation energy conversion preprocessing on the infrared monitoring data to obtain the air temperature. The data preprocessing module includes a wireless transmission module, which transmits the arc resistance and air temperature to the data analysis module via the wireless transmission module.

[0047] The data analysis module is connected to the wireless transmission module in the data acquisition module and is used to make judgments based on the air temperature and electrical quantity obtained by the data acquisition module;

[0048] Among them, the normal ambient temperature and the normal full-load operation of overhead lines are 300K and 343K. The normal combustion of air arc can reach above 6000K. The air conductivity changes with temperature. When the air temperature is 3000K, the conductivity is low. This is because high temperature will reduce the collision frequency of gas molecules, so that the flow of electrons is restricted, the conductivity is relatively weak, and it is difficult for the air medium to break down to form an arc. When the air temperature is 6000K, the conductivity increases. This is mainly because the high temperature enhances the excited state of gas molecules, and electrons can more easily obtain enough energy to form and maintain an arc. Under this conductivity, the arc can burn stably. Therefore, when the infrared temperature is below 3000K, it can be considered that there is no air arc. Above 6000K, the arc burns stably. At 3000K-6000K, the arc is not very stable.

[0049] The relationship between air conductivity and air temperature is that conductivity increases with temperature because more molecules are in an excited state at high temperatures and can participate in the conduction process. At high temperatures above 6000K, air can support stable arc burning. Therefore, in infrared temperature measurement applications, if the measured value is lower than 3000K, obvious air arc phenomenon is usually not observed; above 6000K, infrared detection may show the presence of arc.

[0050] When the system is operating normally, the phase voltage of the overhead line is a sinusoidally varying AC power supply, and the current is 0 until a single-phase arc grounding occurs in the line, the air gap is broken down, the current rises, and the phase voltage drops. The ratio between voltage and current can be used to obtain the arc resistance at which the arc grounding occurs. When the air arc resistance is higher than a certain value, the arc can be considered to be extinguished, and if it is lower than this value, the arc can be considered to be burning.

[0051] When the air temperature obtained by infrared temperature measurement is below 3000K and the air arc resistance is higher than the set value, the arc is judged to be extinguished;

[0052] When the air temperature obtained by infrared temperature measurement is above 6000K and the air arc resistance is lower than the set value, the arc is judged to be burning;

[0053] The output module is connected to the data analysis module and outputs the judgment result of the arc occurrence obtained by the data analysis module.

[0054] like Figure 2 As shown, Embodiment 2 of the present invention proposes an air intermittent arc monitoring method based on multi-data fusion, which specifically includes the following steps:

[0055] Step 1: An infrared temperature measuring device and an electrical quantity measuring device are installed on all the towers on the overhead line to collect infrared monitoring data and electrical quantity measurement data;

[0056] The infrared temperature measuring device has a sensor that converts the infrared signal on the overhead line captured on the overhead line into an electrical signal. The receiver in the infrared temperature measuring device converts the electrical signal into a digital signal, amplifies and filters the digital signal, and obtains infrared monitoring data. The infrared monitoring data contains the radiation energy of the air on the overhead line.

[0057] The infrared measuring device is integrated with the electrical quantity measuring device and placed on the pole tower.

[0058] The electrical quantity measuring device includes a voltage sensor and a current sensor.

[0059] Electrical quantity measurement data include arc voltage and current.

[0060] Step 2: Perform data conversion based on the infrared monitoring data and electrical quantity measurement data collected in step 1 to obtain air temperature and arc resistance;

[0061] The radiation energy of the air in the infrared monitoring data measured by the infrared temperature measuring device is converted into air temperature. The corresponding relationship between the radiation energy and the temperature is expressed by the following formula:

[0062]

[0063] in,

[0064] P b is the air radiation power,

[0065] λ is the wavelength,

[0066] c1 and c2 are radiation constants,

[0067] T is the air temperature.

[0068] When the system is operating normally, the phase voltage of the overhead line is a sinusoidally varying AC power supply and the current is 0 until a single-phase arc grounding occurs in the line, the air gap is broken down, the current rises, and the phase voltage drops. The ratio between voltage and current can be used to obtain the arc resistance where the arc grounding occurs.

[0069] Step 3: According to the air temperature and arc resistance obtained in step 2, combined with the relationship between air temperature and air conductivity and the arc extinction threshold, the arc state is determined.

[0070] The normal ambient temperature and normal full-load operation of overhead lines are 300K and 343K. The normal burning of air arc can reach above 6000K. The conductivity of air changes with temperature. When the air temperature is below 3000K, the conductivity is almost unchanged, and the air medium is difficult to break down and form an arc. When the air temperature is above 6000K, the conductivity begins to change with temperature. At this conductivity, the arc can burn stably. Therefore, when the infrared temperature is below 3000K, it can be considered that there is no air arc. Above 6000K, the arc burns stably. At 3000K-6000K, the arc is not very stable. The relationship between conductivity and temperature is expressed by the following formula:

[0071]

[0072] In the formula,

[0073] T is the air temperature;

[0074] σ is the air conductivity.

[0075] The arc extinction threshold is obtained by an artificial single-phase arc grounding test. During the artificial single-phase arc grounding test, the current is controlled and the generated arc is monitored. When the measured arc resistance rises to a specific threshold, the arc cannot burn and the arc is determined to be extinguished. The specific threshold is used as the arc extinction threshold. When the air arc resistance is higher than the arc extinction threshold, the arc is considered to be extinguished. When the air arc resistance is lower than this value, the arc is considered to be burning.

[0076] The measured air temperature and arc resistance are uniformly collected in the main control cabinet of the substation. When a single-phase grounding arc fault occurs, the control cabinet can clearly know which tower has abnormal temperature and arc resistance data of the infrared temperature measuring device when the fault occurs, and accurately locate the arc.

[0077] In the control cabinet, the air temperature data and arc resistance data are integrated. When the air temperature is lower than 3000K and the arc resistance is higher than the arc extinction threshold, the arc is extinguished.

[0078] When the temperature is between 3000-6000K, the output will show that the arc is in a state of repeated burning and extinction. The judgment result will be fed back to the substation control cabinet. The control cabinet can accurately display the results of intermittent arc, stable burning arc and arc extinction. When the temperature is between 3000-6000K, the arc state judgment will be statistically analyzed.

[0079] When the air temperature is above 6000K and the air arc resistance is lower than the arc extinction threshold, the arc is judged to be burning. The substation control cabinet displays the arc status of all towers and locates the arc.

[0080] Step 4: The substation control cabinet outputs the arc state judgment result obtained in step 3 to realize air intermittent arc monitoring under multi-data fusion.

[0081] The beneficial effect of the present invention is that, compared with the prior art, the present invention combines arc temperature and arc resistance to monitor the occurrence of intermittent arcs in the distribution network, fully considering the electrical and thermal characteristics of the arc as a plasma. The monitoring method proposed in the present invention can be directly applied to actual distribution lines, and the accuracy of identifying and monitoring intermittent arcs in the air of the distribution network is greatly improved, which is of great significance to the safe and stable operation of the distribution network.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. An air intermittent arc monitoring system based on multi-data fusion, comprising: The data acquisition module, the data preprocessing module, the data analysis module and the output module are characterized by: The data acquisition module includes an infrared temperature measuring device and an electrical quantity measuring device, which are used to collect the air radiation energy on the overhead line and the electrical quantity of the overhead line; The data preprocessing module is connected to the data acquisition module and is used to solve the electrical quantity of the overhead line to obtain the arc resistance, and to convert the air radiation energy on the overhead line into air temperature. The data preprocessing module includes a wireless transmission module, which transmits the arc resistance and air temperature to the data analysis module via the wireless transmission module; The data analysis module is connected to the wireless transmission module in the data preprocessing module and is used to make arc judgment based on the air temperature and electrical quantity obtained by the data acquisition module; The output module is connected to the data analysis module, and outputs the judgment result of arc occurrence obtained by the data analysis module, so as to realize the intermittent arc monitoring in air under multi-data fusion.

2. The air intermittent arc monitoring system based on multi-data fusion according to claim 1 is characterized in that: In the data acquisition module, the infrared measuring device is integrated with the electrical quantity measuring device. An infrared temperature measuring device and an electrical quantity measuring device are installed on all towers on the overhead lines. The infrared measuring device collects infrared monitoring data. The electrical quantity measuring device includes a voltage sensor and a current sensor for collecting voltage and current data of the overhead lines.

3. The air intermittent arc monitoring system based on multi-data fusion according to claim 1 is characterized in that: In the data analysis module, when the air temperature obtained by the data preprocessing module is below 3000K and the air arc resistance is higher than the arc extinction threshold, it is judged that the arc is extinguished; When the air temperature obtained by the data preprocessing module is above 6000K and the air arc resistance is lower than the arc extinction threshold, it is judged that the arc is burning.

4. A method for monitoring intermittent arcs in air based on multi-data fusion, used to operate the system for monitoring intermittent arcs in air based on multi-data fusion as claimed in claim 1, characterized in that: Step 1: An infrared temperature measuring device and an electrical quantity measuring device are installed on all the towers on the overhead line to collect infrared monitoring data and electrical quantity measurement data; Step 2: pre-process the infrared monitoring data and electrical quantity measurement data collected in step 1, convert the air radiation energy data in the infrared monitoring data into air temperature, calculate the arc resistance according to the voltage and current data in the electrical quantity measurement data, and obtain the air temperature and arc resistance; Step 3: According to the air temperature and arc resistance obtained in step 2, the relationship between air temperature and air conductivity and the arc extinction threshold are solved respectively, and the arc state is judged by combining the air temperature and arc resistance; Step 4: Output the arc state judgment result obtained in step 3 to realize air intermittent arc monitoring under multi-data fusion.

5. The air intermittent arc monitoring method based on multi-data fusion according to claim 4 is characterized in that: In step 1, the sensor in the infrared temperature measuring device converts the captured infrared signal on the overhead line into an electrical signal, and the receiver in the infrared temperature measuring device converts the electrical signal into a digital signal, and amplifies and filters the digital signal to obtain infrared monitoring data.

6. The air intermittent arc monitoring method based on multi-data fusion according to claim 4 is characterized in that: In step 2, the air radiation energy on the overhead line in the infrared monitoring data measured by the infrared temperature measuring device is converted into air temperature, which is expressed by the following formula: in, Pb is the air radiation power, λ is the wavelength, c1 and c2 are radiation constants, T is the air temperature.

7. The air intermittent arc monitoring method based on multi-data fusion according to claim 4 is characterized in that: In step 2, the phase voltage of the overhead line is a sinusoidally varying AC power supply, the current is 0, the line single-phase arc is grounded, the air gap is broken down, and the arc resistance where the arc grounding occurs is calculated using the ratio between the voltage and the current.

8. The air intermittent arc monitoring method based on multi-data fusion according to claim 4 is characterized in that: In step 3, the relationship between air conductivity and temperature is expressed by the following formula: In the formula, T is the air temperature; σ is the electrical conductivity of air.

9. The air intermittent arc monitoring method based on multi-data fusion according to claim 4 is characterized in that: In step 3, the arc extinction threshold is obtained by an artificial single-phase arc grounding test. During the artificial single-phase arc grounding test, the current is controlled and the generated arc is monitored. When the measured arc resistance rises to the set threshold, the arc cannot burn, and the set threshold is used as the arc extinction threshold.

10. The air intermittent arc monitoring method based on multi-data fusion according to claim 4, characterized in that: In step 3, the measured air temperature and arc resistance are summarized in the substation control cabinet. When a single-phase grounding arc fault occurs, the air temperature and arc resistance data obtained by the infrared temperature measuring devices placed on all the towers of the overhead lines are determined by the substation control cabinet. When the air temperature is below 3000K and the air arc resistance is higher than the arc extinction threshold, it is determined that the arc is extinguished. When the air temperature is above 6000K and the air arc resistance is lower than the arc extinction threshold, the arc is judged to be burning. The substation control cabinet displays the arc status of all towers and locates the arc.

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