Power transmission line fault positioning method based on Beidou time service positioning

Abstract

The invention discloses a power transmission line fault positioning method based on Beidou time service positioning, relates to the technical field of power transmission line fault positioning, and solves the technical problems that a plurality of groups of independent fault sections are difficult to quickly identify, and missed judgment or misjudgment is easily caused. The upstream and downstream topological relation of the positioner is verified in real time, distance measurement deviation caused by time synchronization errors in a traditional traveling wave method is avoided, a fault section can be locked within milliseconds based on comparison of carrier signal strength and a threshold value and through an adjacent pairing rule of downstream fault endpoints and upstream fault endpoints, and the fault section can be locked within milliseconds through an independent endpoint pair matching mechanism. According to the method, multiple groups of discontinuous fault sections can be identified at the same time, missed judgment is avoided, a rule base is constructed based on historical fault data, automatic matching of fault causes is realized, detailed analysis is performed in combination with a multi-dimensional fault level model, fault levels of the fault causes are determined, and resource allocation priorities are guided according to the fault levels.

Description

Technical Field

[0001] The present invention relates to the technical field of transmission line fault location, and in particular to a transmission line fault location method based on Beidou timing positioning. Background Art

[0002] With the development of smart grids, new monitoring methods based on Beidou positioning and Internet of Things technologies are gradually being used.

[0003] According to the patent application with publication number CN118914747A, a transmission line fault location method and system based on Beidou timing and positioning technology are disclosed, including: constructing a state space model based on the parameters of the monitored transmission line; if the value of the dimension of the posterior extended state estimate representing the position of the fault point on the transmission line obtained by the unscented Kalman filter algorithm is non-zero, then entering the next step; inputting the covariance matrix at the first moment and the parameters of the transmission line at the first moment into the instantaneous switching model, and the instantaneous switching model outputs the instantaneous covariance matrix; replacing the covariance matrix at the first moment with the instantaneous covariance matrix, continuing to run the unscented Kalman filter algorithm, and then obtaining the posterior extended state estimate at the third moment, and decoding to obtain the position of the fault point.

[0004] However, existing transmission line fault location technologies mainly rely on traditional electrical quantity analysis methods such as the impedance method and the traveling wave method. For multi-branch, long-distance transmission lines or multiple fault scenarios, traditional two-end ranging or single-end traveling wave methods are easily affected by factors such as transition resistance and signal attenuation, resulting in large positioning errors and difficulty in quickly identifying multiple independent fault sections, which can easily lead to missed or misjudgment. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a transmission line fault location method based on Beidou timing and positioning, which solves the problem of difficulty in quickly identifying multiple groups of independent fault sections, which easily leads to missed judgment or misjudgment.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a transmission line fault location method based on Beidou timing positioning, the method comprising the following steps:

[0007] Compare the carrier signal strength received on the locator with the threshold to determine the locator condition and classify it as normal or abnormal;

[0008] Obtain the corresponding transmission line to be analyzed based on the anomaly locator, and calculate the conductor field strength of the transmission line to be analyzed;

[0009] The noise power and carrier signal power of the transmission line to be analyzed are calculated separately, the signal-to-noise ratio of the transmission line to be analyzed is calculated at the same time, and the abnormal locators are screened to obtain the locator to be analyzed;

[0010] Obtain the locator to be analyzed, determine the fault section according to the fault endpoint judgment rule, and generate fault section information;

[0011] Extract the parameter features of the transmission line parameters corresponding to the fault section, screen the specific causes, and calculate the specific impact score and maintenance difficulty score corresponding to the specific causes;

[0012] The specific impact score is summed with the maintenance difficulty score to obtain the fault cause index, and the fault level is determined according to the fault level interval matching table to generate fault level information.

[0013] As a further solution of the present invention, the specific method of determining the locator condition and classifying the locator as normal or abnormal is as follows:

[0014] Obtain basic information of the locator on the transmission line, collect the carrier signal of its receiver, record the signal sender, direction and strength, and compare the signal strength with the threshold set by the operator. If the strength is greater than the threshold, it is a normal locator, otherwise it is an abnormal locator.

[0015] As a further solution of the present invention, the method for calculating the conductor field strength of the transmission line to be analyzed is:

[0016] Get all the anomaly locators and get the transmission line at a distance L before the anomaly locator as the transmission line to be analyzed. At the same time, calculate the conductor field strength of the transmission line to be analyzed. According to the formula The field strength E corresponding to the transmission line to be analyzed is calculated, where U is the ground voltage of the transmission line to be analyzed, n is the number of split conductors, r is the radius of the transmission line to be analyzed, d is the split spacing, and D is the distance between the conductor and the equivalent mirror image of the earth.

[0017] As a further solution of the present invention, the specific method of calculating the signal power of the power transmission line to be analyzed is:

[0018] Obtain the power of the corresponding transmitting end of the transmission line to be analyzed and record it as the transmitting power P tx , through the distribution parameter model Calculate the conductor transmission attenuation A, where R is the conductor DC resistance attenuation, f is the carrier frequency, and f c is the corona critical frequency;

[0019] The obtained transmission power P tx Substitute the wire transmission attenuation A into the formula P rx =P tx The signal power at the receiving end is calculated by -A·L and recorded as the received power P rx , where L is the length of the transmission line to be analyzed.

[0020] As a further solution of the present invention, the specific method of calculating the noise power of the transmission line to be analyzed is:

[0021] Obtain the field strength E of the transmission line to be analyzed and the corresponding critical value field strength E0, according to the formula P corona =K+20log 10 (E-E0)+10log 10 (f)+10log 10 (L) Calculate the corona noise power P corona , where K is the environmental correction factor;

[0022] According to the formula P thermal =-174+10log 10 (B) Calculate the thermal noise power, where B is the noise bandwidth;

[0023] The corona noise, thermal noise and external electromagnetic interference obtained by analysis are summed and calculated according to the formula Calculate the total noise power P total , where P EMI External electromagnetic interference.

[0024] As a further solution of the present invention, the specific method of screening abnormal locators to obtain locators to be analyzed is:

[0025] Substitute the analyzed signal power and noise power into the formula The signal-to-noise ratio (SNR) of the transmission line to be analyzed is calculated and compared with a preset value. The abnormal locator corresponding to the signal-to-noise ratio (SNR) smaller than the preset value is marked as the locator to be analyzed.

[0026] As a further solution of the present invention, the specific method of generating the fault section information is:

[0027] The locator to be analyzed is labeled as i, and i = 1, 2, ..., j, where j represents the number of locators to be analyzed. If two adjacent locators to be analyzed are detected, the wire section between them is determined to be the fault section. The corresponding coordinates are obtained through Beidou positioning, the starting and ending positions of the fault section are calculated, and the fault section information is generated.

[0028] As a further solution of the present invention, the specific method for calculating the specific impact score and the maintenance difficulty score corresponding to the specific cause is:

[0029] Obtain the specific cause and the specific impact corresponding to the specific cause based on historical data, and score the specific impact to obtain a specific impact score;

[0030] Score the maintenance difficulty, obtain the duration of the cause according to historical data, and derive the time scoring index. At the same time, obtain the repair difficulty corresponding to the specific cause, and determine the corresponding score based on the repair difficulty to obtain the repair difficulty scoring index. According to the formula: Maintenance Difficulty Score = Time Scoring Index × Weight One + Repair Difficulty Score Index × Weight Two, the maintenance difficulty index is calculated, and the specific values of Weight One and Weight Two are set by the operator.

[0031] As a further solution of the present invention, the specific method of generating the fault level information is:

[0032] The specific impact score and the maintenance difficulty score obtained from the analysis are summed, and the fault cause index is calculated according to the formula: fault cause index = specific impact score × a1 + maintenance difficulty score × a2. Here, a1 and a2 are corresponding weight coefficients, and the specific values are set by the operator. Then, the obtained fault cause index is matched with the fault level interval matching table to generate fault level information.

[0033] The present invention provides a method for locating transmission line faults based on Beidou timing and positioning. Compared with the existing technology, it has the following advantages:

[0034] The present invention obtains centimeter-level coordinates of the locator through Beidou, verifies the upstream and downstream topological relationship of the locator in real time, avoids the ranging deviation caused by time synchronization error of the traditional traveling wave method, and compares the carrier signal strength with the threshold. Through the "downstream fault endpoint + upstream fault endpoint" adjacent pairing rule, the fault section can be locked within milliseconds. Through the independent endpoint pair matching mechanism, multiple groups of non-continuous fault sections can be identified at the same time to avoid missed judgments. A rule base is built based on historical fault data to realize automatic matching of fault causes. At the same time, a detailed analysis is carried out in combination with a multi-dimensional fault level model to determine the fault level of the fault cause and guide the resource allocation priority according to the fault level. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a diagram of the steps of the present invention. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] See also Figure 1 The present application provides a method for locating a transmission line fault based on Beidou timing positioning, which specifically includes the following steps:

[0038] Step 1: Obtain basic information of the locator on the transmission line, including the tower number and longitude and latitude. At the same time, obtain the carrier signal of the receiver on the locator. Specifically, each locator's receiver can simultaneously receive the carrier signals of the upstream and downstream locators, and obtain the sender and direction of the carrier signal. The signal strength of the carrier signal is compared with a threshold value, and the specific value of the threshold is set by the operator.

[0039] If the signal strength is greater than the threshold, it indicates that the corresponding locator is normal and is recorded as a normal locator. Conversely, if the signal strength is less than the threshold, it indicates that the corresponding positioning is abnormal and is recorded as an abnormal locator.

[0040] Step 2: Get all the abnormal locators and get the transmission line with a distance L before the abnormal locator as the transmission line to be analyzed. Here, the distance L is the locator placement distance. In short, get the transmission line between the adjacent locators before the abnormal locator. At the same time, calculate the conductor field strength of the transmission line to be analyzed. According to the formula Calculate the electric field strength E corresponding to the transmission line to be analyzed, where U is the voltage to ground of the transmission line to be analyzed, n is the number of split conductors. High-voltage lines often use split conductors (such as 2-split or 4-split) to reduce the electric field strength, r is the radius of the transmission line to be analyzed, d is the split spacing, and D is the distance between the conductor and the equivalent mirror image of the earth. Similarly, calculate the electric field strength E of all transmission lines to be analyzed;

[0041] Step 3. Then, the noise power and carrier signal power of the transmission line to be analyzed are calculated separately. The signal power is calculated as follows:

[0042] Obtain the power of the corresponding transmitting end of the transmission line to be analyzed and record it as the transmitting power P tx , and is determined by the carrier signal generator of the fault locator. Since the carrier signal is attenuated due to the resistance, inductance, and capacitance effects when it is transmitted along the wire, the wire transmission attenuation A is calculated using the distributed parameter model. The specific formula is: Where R is the DC resistance attenuation of the conductor (can be obtained by looking up the table), f is the carrier frequency, f c is the corona critical frequency, where the corona critical frequency f c The calculation formula is E0 is the critical field strength, k is the empirical coefficient, and the wire transmission attenuation A is calculated according to the above formula;

[0043] The obtained transmission power P tx Substitute the wire transmission attenuation A into the formula P rx =P tx The signal power at the receiving end is calculated by -A·L and recorded as the received power P rx , where L is the length of the transmission line to be analyzed;

[0044] The noise power is calculated, and the noise power includes corona noise, thermal noise and external electromagnetic interference. The total noise power is the linear superposition (not decibel superposition) of the power of each noise source. The method for calculating the corona noise is:

[0045] Obtain the field strength E of the transmission line to be analyzed and the corresponding critical field strength E0. When the field strength E>E0, corona discharge generates broadband noise, and the calculation formula is P corona =K+20log 10 (E-E0)+10log 10 (f)+10log 10 (L), the corona noise power P is calculated according to the above formula corona , where K is the environmental correction factor (-120 to -100dBm), -110dBm for sunny weather and -90dBm for rainy days, for example: E = 35kV / cm, f = 200kHz,

[0046] L = 10kmK = -110dB, then P corona =-110+20log 10 (5)+10log 10 (2x105)+10log 10 (10)=-110+14+53+10=-33dBm;

[0047] The specific way to calculate thermal noise is that the specific thermal noise is generated by the wire resistance and the ambient temperature, and the calculation formula is P thermal =-174+10log 10 (B), where B is the noise bandwidth, which is equal to the carrier signal bandwidth. For example, if bandwidth B = 10 kHz, then:

[0048] Pthermal=-174+10log 10 (10 4 )=-174+40=-134dBm;

[0049] Analyze external electromagnetic interference, including interference from lightning, industrial equipment, etc. The measured value is usually -100 to -80dBm, with a typical value of -90dBm;

[0050] The corona noise, thermal noise and external electromagnetic interference obtained by analysis are summed and calculated. First, the noise power is converted from dBm to linear power (mW), then summed and finally converted back to dBm. According to the formula Calculate the total noise power P total , where P EMI External electromagnetic interference;

[0051] For example: If P corona =-33dBm, P thermal =-134dBm, P EMI =-90dBm, then P corona =10 -33 / 10 =5.01x10 -4 , P therma1 =10 -134 / 10 =3.98x10 -14 , P EMI =10 -90 / 10 =1x10 -9 mW, P tota1 (dBm)=10log 10 (5.01x10 -4 )≈-33dBm;

[0052] Substitute the analyzed signal power and noise power into the formula The signal-to-noise ratio (SNR) of the transmission line to be analyzed is calculated and compared with a preset value. The preset value represents a normal signal-to-noise ratio. The specific value is set by the operator. If the signal-to-noise ratio (SNR) is less than the preset value, it indicates that there is an abnormality in the transmission line to be analyzed, and the corresponding abnormal locator is obtained and marked as the locator to be analyzed. On the contrary, if the signal-to-noise ratio (SNR) is greater than the preset value, it indicates that the transmission line to be analyzed is normal and is not processed.

[0053] Step 4: Obtain all the locators to be analyzed and determine the fault section based on the locators to be analyzed. The specific determination method is as follows:

[0054] The locator to be analyzed is labeled as i, and i=1, 2, ..., j, where j represents the number of locators to be analyzed. At the same time, the upstream and downstream relationship of the locator to be analyzed i is determined. The upstream and downstream relationship is determined according to the power flow direction of the transmission line and analyzed according to the fault endpoint judgment rule. The judgment rule is as follows:

[0055] Downstream fault endpoint: The locator status is faulty, and the downstream adjacent locator status is normal (or there is no downstream device).

[0056] Upstream fault endpoint: The locator status is faulty, and the upstream adjacent locator status is normal (or there is no upstream device);

[0057] If two adjacent fault endpoints are detected (such as locator B is the downstream fault endpoint and locator C is the upstream fault endpoint), the conductor section between the two is determined to be the fault section. At the same time, the coordinates of the two adjacent fault endpoints are obtained according to Beidou positioning, and the starting and ending positions of the fault section are calculated to generate the fault section information.

[0058] For example, when the system determines that B is the downstream fault endpoint and C is the upstream fault endpoint through status scanning, it queries the latest coordinates of the two from the database and checks whether the coordinate timestamp is within the valid time window (such as ≤1 hour). Expired data triggers a locator communication alarm, verifies whether the longitude and latitude are within a reasonable range (such as longitude -180 to 180, latitude -90 to 90), excludes invalid data (such as the default value when no satellite is located), and compares historical coordinates. If the coordinate change of the same device exceeds a threshold (such as 50 meters), it indicates that the device may have shifted and requires manual confirmation.

[0059] If the system needs to be connected to a GIS map, the WGS84 coordinates collected by Beidou need to be converted into a local plane coordinate system. Proj4js, GDAL and other libraries are used here to implement the coordinate conversion. According to the topological order, the locator with a smaller number is the starting point (for example, the topological order of B is 2 and C is 3, so the starting point is B), and the locator with a larger number is the end point (for example, C is the end point).

[0060] Step 5: Obtain the fault section information, obtain the transmission line parameters corresponding to the fault section, and extract the parameter features corresponding to the transmission line parameters. Compare the obtained parameter features with the "feature-cause" mapping rule base to screen the specific cause corresponding to the fault section. The "feature-cause" mapping rule base is preset by the operator. Determine the fault level based on the specific cause obtained. The specific method for determining the fault level is as follows:

[0061] Obtain the specific cause, and calculate the impact range and maintenance difficulty of the specific cause at the same time, and assign corresponding fault index scores to the impact range and maintenance difficulty respectively. The specific method of assigning fault index scores to the impact range is to obtain the specific impact corresponding to the specific cause based on historical data, and then score the specific impact to obtain a specific impact score. For a single branch line (<10 households), the score is 1 point; for a regional power grid (100-1000 households), the score is 3 points; for a city-wide power grid (>10,000 households), the score is 5 points;

[0062] Then, the maintenance difficulty is scored. Similarly, the duration corresponding to the specific cause is obtained according to historical data, and the corresponding time scoring index is obtained based on the duration. Specifically, if the duration is <1 hour, the score is 1 point, the duration is between 1-4 hours, the score is 3 points, and the duration is greater than 4 hours, the score is 5 points. At the same time, the repair difficulty corresponding to the specific cause is obtained, and the corresponding score is determined according to the repair difficulty to obtain the repair difficulty scoring index. Specifically, if the repair difficulty is that the local team can handle it, the score is 1, if the repair difficulty is that external support is required, the score is 3 points, and if the repair difficulty is that customized spare parts + expert consultation are required, the score is 5 points. At the same time, the obtained time scoring index and repair difficulty scoring index are summed, and the repair difficulty index is calculated according to the formula Maintenance Difficulty Score = Time Scoring Index × Weight 1 + Repair Difficulty Scoring Index × Weight 2, and the specific values of Weight 1 and Weight 2 are set by the operator;

[0063] The specific impact score and the maintenance difficulty score obtained from the analysis are summed, and the fault cause index is calculated according to the formula Fault Cause Index = Specific Impact Score × a1 + Maintenance Difficulty Score × a2, where a1 and a2 are corresponding weight coefficients, and the specific values are set by the operator. Then, the obtained fault cause index is matched with the fault level interval matching table, as shown in the following table:

[0064]

[0065] Fault level information is generated based on the fault level interval matching table.

[0066] Some of the data in the above formulas are calculated based on their numerical values and are not substituted into parameter units for calculation. At the same time, the contents not described in detail in this specification belong to the existing technology known to those skilled in the art.

[0067] The above embodiments are only used to illustrate the technical method of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical method of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A transmission line fault location method based on Beidou timing positioning, characterized in that: The method comprises the following steps: Compare the carrier signal strength received on the locator with the threshold to determine the locator condition and classify it as normal or abnormal; Obtain the corresponding transmission line to be analyzed based on the anomaly locator, and calculate the conductor field strength of the transmission line to be analyzed; The noise power and carrier signal power of the transmission line to be analyzed are calculated separately, the signal-to-noise ratio of the transmission line to be analyzed is calculated at the same time, and the abnormal locators are screened to obtain the locator to be analyzed; Obtain the locator to be analyzed, determine the fault section according to the fault endpoint judgment rule, and generate fault section information; Extract the parameter features of the transmission line parameters corresponding to the fault section, screen the specific causes, and calculate the specific impact score and maintenance difficulty score corresponding to the specific causes; The specific impact score is summed with the maintenance difficulty score to obtain the fault cause index, and the fault level is determined according to the fault level interval matching table to generate fault level information.

2. The method for locating a transmission line fault based on Beidou timing and positioning according to claim 1, characterized in that: The specific method of judging the locator status and classifying the locator as normal or abnormal is as follows: Obtain basic information of the locator on the transmission line, collect the carrier signal of its receiver, record the signal sender, direction and strength, and compare the signal strength with the threshold set by the operator. If the strength is greater than the threshold, it is a normal locator, otherwise it is an abnormal locator.

3. The method for locating a transmission line fault based on Beidou timing and positioning according to claim 1, characterized in that: The method for calculating the conductor field strength of the transmission line to be analyzed is: Get all the anomaly locators and get the transmission line at a distance L before the anomaly locator as the transmission line to be analyzed. At the same time, calculate the conductor field strength of the transmission line to be analyzed. According to the formula The field strength E corresponding to the transmission line to be analyzed is calculated, where U is the ground voltage of the transmission line to be analyzed, n is the number of split conductors, r is the radius of the transmission line to be analyzed, d is the split spacing, and D is the distance between the conductor and the equivalent mirror image of the earth.

4. The method for locating a transmission line fault based on Beidou timing and positioning according to claim 1, characterized in that: The specific method for calculating the signal power of the transmission line to be analyzed is: Obtain the power of the corresponding transmitting end of the transmission line to be analyzed and record it as the transmitting power P tx , through the distribution parameter model Calculate the conductor transmission attenuation A, where R is the conductor DC resistance attenuation, f is the carrier frequency, and f c is the corona critical frequency; The obtained transmission power P tx Substitute the wire transmission attenuation A into the formula P rx =P tx The signal power at the receiving end is calculated by -A·L and recorded as the received power P rx , where L is the length of the transmission line to be analyzed.

5. The method for locating a transmission line fault based on Beidou timing and positioning according to claim 1, characterized in that: The specific method for calculating the noise power of the transmission line to be analyzed is: Obtain the field strength E of the transmission line to be analyzed and the corresponding critical value field strength E0, according to the formula P corona =K+20log 10 (E-E0)+10log 10 (f)+10log 10 (L) Calculate the corona noise power P corona , where K is the environmental correction factor; According to the formula P thermal =-174+10log 10 (B) Calculate the thermal noise power, where B is the noise bandwidth; The corona noise, thermal noise and external electromagnetic interference obtained by analysis are summed and calculated according to the formula Calculate the total noise power P total , where P EMI External electromagnetic interference.

6. The method for locating a transmission line fault based on Beidou timing and positioning according to claim 1, characterized in that: The specific method of screening abnormal locators to obtain the locators to be analyzed is: Substitute the analyzed signal power and noise power into the formula The signal-to-noise ratio (SNR) of the transmission line to be analyzed is calculated and compared with a preset value. The abnormal locator corresponding to the signal-to-noise ratio (SNR) smaller than the preset value is marked as the locator to be analyzed.

7. The method for locating a transmission line fault based on Beidou timing and positioning according to claim 1, characterized in that: The specific method of generating the fault section information is as follows: The locator to be analyzed is labeled as i, and i = 1, 2, ..., j, where j represents the number of locators to be analyzed. If two adjacent locators to be analyzed are detected, the wire section between them is determined to be the fault section. The corresponding coordinates are obtained through Beidou positioning, the starting and ending positions of the fault section are calculated, and the fault section information is generated.

8. The method for locating a transmission line fault based on Beidou timing and positioning according to claim 1, characterized in that: The specific method for calculating the specific impact score and the repair difficulty score corresponding to the specific cause is as follows: Obtain the specific cause and the specific impact corresponding to the specific cause based on historical data, and score the specific impact to obtain a specific impact score; Score the maintenance difficulty, obtain the duration of the cause according to historical data, and derive the time scoring index. At the same time, obtain the repair difficulty corresponding to the specific cause, and determine the corresponding score based on the repair difficulty to obtain the repair difficulty scoring index. According to the formula: Maintenance Difficulty Score = Time Scoring Index × Weight One + Repair Difficulty Score Index × Weight Two, the maintenance difficulty index is calculated, and the specific values of Weight One and Weight Two are set by the operator.

9. The method for locating a transmission line fault based on Beidou timing and positioning according to claim 1, characterized in that: The specific method of generating the fault level information is as follows: The specific impact score and the maintenance difficulty score obtained from the analysis are summed, and the fault cause index is calculated according to the formula: fault cause index = specific impact score × a1 + maintenance difficulty score × a2. Here, a1 and a2 are corresponding weight coefficients, and the specific values are set by the operator. Then, the obtained fault cause index is matched with the fault level interval matching table to generate fault level information.

Images