A park power supply line short circuit fault diagnosis method and system

Abstract

The application relates to a park power supply line short-circuit fault diagnosis method and system, which comprises the following steps: based on the monitoring data of each monitoring point on each power supply line in the park and a pre-constructed knowledge experience base, an edge computing technology is used to pre-judge whether a short-circuit fault will occur in the park power supply line and the short-circuit fault type when the short-circuit fault occurs; when the short-circuit fault is about to occur, a fault current phase analysis technology is used to locate the fault point of the power supply line in the park where the short-circuit fault will occur; wherein the pre-constructed knowledge experience base is determined based on the electric quantity characteristics of the fault phase when the historical short-circuit fault of each power supply line in the park occurs. The technical scheme provided by the application can accurately pre-judge whether a short-circuit fault will occur in the park power supply line and the short-circuit fault type when the short-circuit fault occurs in advance, and locate the fault point of the power supply line where the short-circuit fault occurs, so that the holographic perception of the power quality of the park power supply line is realized.

Description

Technical Field

[0001] This invention relates to the field of fault diagnosis technology, specifically to a method and system for diagnosing short-circuit faults in power supply lines in industrial parks. Background Technology

[0002] The park is of great significance to regional economic development, industrial restructuring, independent innovation, urbanization and cultural shaping.

[0003] Power line faults in industrial parks can disrupt normal power supply and the safe operation of equipment. The most common type of power line fault is a short circuit. When a short circuit occurs, the reduced impedance of the power supply circuit and the transient process during the sudden short circuit cause a significant increase in the short-circuit current, potentially exceeding the rated current and burning out electrical equipment. Furthermore, conductors may deform or be damaged due to the impact of strong electrodynamic forces. The short circuit also causes a voltage drop in the industrial park's grid, particularly near the short-circuit point, which could disrupt power supply to some park users. Therefore, predicting short-circuit faults in industrial park power lines is a crucial issue.

[0004] Currently, the diagnosis of short-circuit faults in the power supply lines of the park is still at the basic stage of repairing after a fault occurs, with little involvement in short-circuit fault prediction technology. Moreover, the publicly available fault prediction technology only uses the qualitative analysis results of voltage and current amplitude as the basis for fault prediction. Therefore, the accuracy of fault prediction is low and cannot guarantee the safe and efficient operation of the park. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method for diagnosing short-circuit faults in power supply lines within a park. This method can identify in advance which power supply lines within the park will experience short-circuit faults, as well as the type of short-circuit fault that will occur, thereby achieving a holographic perception of the power quality of the park's power supply lines.

[0006] Specifically, it includes:

[0007] Based on the monitoring data of each monitoring point on each power supply line in the park and the pre-built knowledge and experience database, edge computing technology is used to predict whether a short circuit fault will occur on the power supply line in the park and the type of short circuit fault when it occurs.

[0008] When a short circuit fault is imminent, fault current phase analysis technology is used to locate the fault point of the power supply line in the park that will experience a short circuit fault.

[0009] The pre-built knowledge and experience base is determined by the electrical characteristics of the fault phase during historical short-circuit faults of each power supply line in the park.

[0010] Preferably, the monitoring data includes: phase voltage, phase current, phase zero-sequence voltage, and phase zero-sequence current;

[0011] The electrical characteristics include: voltage change rate, current change rate, presence of zero-sequence voltage, and presence of zero-sequence current;

[0012] The fault types include: single-phase short-circuit fault, two-phase short-circuit fault, two-phase-to-ground short-circuit fault, and three-phase short-circuit fault;

[0013] The single-phase short-circuit fault includes: phase A short-circuit fault, phase B short-circuit fault and phase C short-circuit fault;

[0014] The two-phase short-circuit faults include: AB phase short-circuit fault, BC phase short-circuit fault and AC phase short-circuit fault;

[0015] The two-phase-to-ground short-circuit fault includes: AB phase-to-ground short-circuit fault, BC phase-to-ground short-circuit fault and AC phase-to-ground short-circuit fault.

[0016] Furthermore, the construction process of the pre-built knowledge and experience base includes:

[0017] Obtain the rate of change of current and voltage of each power supply line in the park at the time of occurrence of various short-circuit faults;

[0018] The minimum value of the current change rate / voltage change rate of each power supply line in the park at all times of occurrence of various short-circuit faults is taken as the warning threshold for voltage change rate / current change rate of each power supply line in the park under various short-circuit faults.

[0019] A knowledge and experience base is generated based on the warning thresholds for voltage change rate, current change rate, zero-sequence voltage, and zero-sequence current of the fault phases of various power supply lines in the park under various short-circuit faults.

[0020] The presence of zero-sequence voltage and zero-sequence current in the fault phase under various short-circuit faults is predetermined.

[0021] Furthermore, the voltage change rate of the faulty phase / each phase is calculated based on the normal operating voltage amplitude and the reduced voltage amplitude using the voltage change rate calculation formula;

[0022] The current change rate of the faulty phase / each phase is calculated based on the normal operating current amplitude and the value after the current amplitude is increased, using the current change rate calculation formula.

[0023] Furthermore, the formula for calculating the rate of change of current is as follows:

[0024]

[0025] In the formula, I d I represents the value after the current amplitude is increased. e The normal operating current amplitude is given by τ, where τ is the decay time constant of the free component. The rate of change of current;

[0026] The formula for calculating the decay time constant τ of the free component is as follows:

[0027]

[0028] In the formula, K M This is the short-circuit current impact coefficient;

[0029] The formula for calculating the voltage change rate is as follows:

[0030]

[0031] In the formula, U d U represents the value after the voltage amplitude has decreased. e The voltage amplitude is the normal operating voltage, and ΔU% is the voltage change rate.

[0032] Furthermore, based on monitoring data from each monitoring point on each power supply line in the park and a pre-built knowledge and experience base, edge computing technology is used to predict whether a short circuit fault will occur on the park's power supply lines and the type of short circuit fault if it does occur, including:

[0033] Edge computing is performed on the monitoring data of each monitoring point on each power supply line in the park to determine the electrical characteristics of each phase at each monitoring point on each power supply line in the park.

[0034] By utilizing the electrical characteristics of each phase at each monitoring point on each power supply line in the park and the knowledge and experience database, we can predict whether a short circuit fault will occur on the power supply lines in the park and what type of short circuit fault will occur.

[0035] Furthermore, by utilizing the electrical characteristics of each phase at each monitoring point on each power supply line in the park and a knowledge and experience database, the system predicts whether a short circuit fault will occur on the park's power supply lines and the type of short circuit fault that will occur, including:

[0036] The voltage change rate, current change rate, zero-sequence voltage presence, and zero-sequence current presence of each phase at each monitoring point on each power supply line in the park are compared with the voltage change rate warning threshold, current change rate warning threshold, zero-sequence current presence, and zero-sequence voltage presence of the fault phase on each power supply line in the park under various short-circuit faults.

[0037] If the voltage change rate, current change rate, zero-sequence voltage presence, and zero-sequence current presence of each phase at any monitoring point on the power supply line in the park meet the judgment criteria when compared with the warning thresholds for voltage change rate, current change rate, zero-sequence current presence, and zero-sequence voltage presence of the fault phase under any type of short-circuit fault, then the power supply line in the park is about to experience a short-circuit fault of the corresponding type; otherwise, the power supply line in the park is operating normally.

[0038] Furthermore, the determination condition must simultaneously satisfy the following constraints:

[0039] The voltage change rate of the corresponding phase of the power supply line in the park is greater than the difference between the voltage change rate warning threshold and the preset minimum value of the faulty phase.

[0040] The rate of change of current in the corresponding phase of the power supply line in the park is greater than the difference between the warning threshold for the rate of change of current in the faulty phase and the preset minimum value.

[0041] The zero-sequence voltage and zero-sequence current of the corresponding phases of the power supply lines in the park are consistent with those of the faulty phase.

[0042] Preferably, when a short-circuit fault is about to occur, fault current phase analysis technology is used to locate the fault point of the power supply line in the park where a short-circuit fault will occur, including:

[0043] Based on the voltage amplitude and phase angle at each monitoring point on the power supply line that is about to experience a short circuit fault in the park, the fault current phase analysis technology is used to determine the fault direction at each point on the power supply line that is about to experience a short circuit fault in the park.

[0044] Based on the fault direction at each point on the power supply line in the park that is about to experience a short circuit, locate the fault point of the power supply line in the park that is about to experience a short circuit.

[0045] The fault direction includes forward faults and reverse faults; a forward fault is when the fault current is in the same direction as the line power flow, and a reverse fault is when the fault current is in the opposite direction to the line power flow.

[0046] Based on the same inventive concept, the present invention also provides a short-circuit fault diagnosis system for power supply lines in industrial parks, the system comprising:

[0047] The prediction module is used to predict whether a short circuit fault will occur on the power supply lines in the park and the type of short circuit fault when it occurs, based on the monitoring data of each monitoring point on each power supply line in the park and the pre-built knowledge and experience base, using edge computing technology.

[0048] The positioning module is used to locate the fault point of the power supply line in the park that will experience a short circuit when a short circuit fault is about to occur, by employing fault current phase analysis technology.

[0049] The pre-built knowledge and experience base is determined by the electrical characteristics of the fault phase during historical short-circuit faults of each power supply line in the park.

[0050] Compared with the closest existing technology, the present invention has the following advantages:

[0051] This invention provides a method and system for diagnosing short-circuit faults in power supply lines within a park. The method includes: using edge computing technology to predict whether a short-circuit fault will occur in the park's power supply lines and the type of short-circuit fault if it does occur, based on monitoring data from monitoring points on each power supply line within the park and a pre-built knowledge and experience database; when a short-circuit fault is imminent, using fault current phase analysis technology to locate the fault point of the power supply line in the park where the short-circuit fault will occur; wherein the pre-built knowledge and experience database is determined based on the electrical characteristics of the fault phase during historical short-circuit faults in each power supply line within the park; the technical solution provided by this invention can accurately predict whether a short-circuit fault will occur in the park's power supply lines and the type of short-circuit fault if it does occur, and locate the fault point of the power supply line where the short-circuit fault will occur, thus achieving holographic perception of the power quality of the park's power supply lines. Attached Figure Description

[0052] Figure 1 A flowchart of a short-circuit fault prediction method for power supply lines in a park provided by the present invention;

[0053] Figure 2 This is a schematic diagram of a power supply line section in an embodiment of the present invention;

[0054] Figure 3 This invention provides a structural diagram of a short-circuit fault prediction system for power supply lines in industrial parks. Detailed Implementation

[0055] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] Here we will first explain some of the terms involved in this invention.

[0058] Edge computing: With the development of IoT technology, data is growing explosively, and traditional cloud computing is struggling to process and compute massive amounts of data. Edge computing is a product designed to solve this problem. Edge computing refers to analyzing and computing data at the edge of devices or networks. Compared to cloud computing, this computing model is faster, can handle larger amounts of data, and offers better data privacy and security.

[0059] The park will be equipped with a large number of sensors, smart circuit breakers, smart meters and IoT smart gateways to collect power data of the power supply lines. Edge computing can be used to analyze and monitor the data in real time.

[0060] Fault current phase analysis technology is a technique that determines the fault direction based on the fault current, thereby achieving precise fault location. After a short-circuit fault occurs in a power supply line, if it is a symmetrical short-circuit fault, the fundamental current component is separated from the fault current information; if it is an asymmetrical short-circuit fault, the positive sequence component is extracted. By differentiating the current components, a fault detection direction model of the reference current vector is established, and the fault current phasor and reference phasor are calculated using forward or reverse faults to set fault direction criteria. Based on the fault direction criteria, the fault direction is accurately identified, thereby achieving fault location and facilitating rapid arrival and fault elimination by emergency repair personnel.

[0061] Example 1:

[0062] This invention provides a method for diagnosing short-circuit faults in power supply lines within a park, such as... Figure 1 As shown, it includes:

[0063] Step 101: Based on the monitoring data of each monitoring point on each power supply line in the park and the pre-built knowledge and experience base, edge computing technology is used to predict whether a short circuit fault will occur on the power supply line in the park and the type of short circuit fault when it occurs.

[0064] Step 102: When there is an impending short-circuit fault, fault current phase analysis technology is used to locate the fault point of the power supply line in the park where a short-circuit fault will occur.

[0065] The pre-built knowledge and experience base is determined by the electrical characteristics of the fault phase during historical short-circuit faults of each power supply line in the park.

[0066] In an embodiment of the present invention, the specific steps of the present invention include: Step 101, based on the monitoring data of each monitoring point on each power supply line in the park and the pre-built knowledge and experience base, edge computing technology is used to predict whether a short circuit fault will occur on the power supply line in the park and the type of short circuit fault when a short circuit fault occurs.

[0067] Step 101 specifically includes:

[0068] Step 101-1: Obtain monitoring data from each monitoring point in each power supply line of the park. The monitoring data includes phase voltage, phase current, phase zero-sequence voltage, and phase zero-sequence current.

[0069] In actual operation, the voltage acquisition module and the current acquisition module are used to acquire the three-phase voltage, three-phase current, zero-sequence voltage and zero-sequence current signals;

[0070] Step 101-2: Perform edge computing on the monitoring data of each monitoring point on each power supply line in the park to determine the electrical characteristics of each phase at each monitoring point on each power supply line in the park; the electrical characteristics include: voltage change rate, current change rate, presence of zero-sequence voltage and presence of zero-sequence current;

[0071] Specifically, the current of each phase at each monitoring point on each power supply line in the park is processed using the current change rate calculation formula to obtain the current change rate of each phase at each monitoring point on each power supply line in the park. The voltage change rate calculation formula is then used to process the current of each phase at each monitoring point on each power supply line in the park to obtain the voltage change rate of each phase at each monitoring point on each power supply line in the park.

[0072] If the zero-sequence voltage or zero-sequence current of each phase is not zero, then the zero-sequence voltage or zero-sequence current of each phase exists; otherwise, it does not exist.

[0073] Edge computing is a technology that analyzes and computes monitoring data close to the device or network edge. It places high demands on the monitoring data, such as more accurate time synchronization, heterogeneous system interconnection, and intelligence. Edge computing primarily utilizes heterogeneous computing to meet the computational needs of various business applications, performing parallel computations on the data across heterogeneous computing systems. Depending on the requirements, heterogeneous computing can support standalone computers using SIMD (Simplified Chinese IDE) or independent computers interconnected by self-organizing networks of IoT communication networks such as HPLC and VPN. Therefore, in practical operation, by installing edge servers and adding current and voltage change rate calculation modules to them, the operating status of the campus power supply lines can be calculated and analyzed in real time.

[0074] Step 101-3: Using the electrical characteristics of each phase at each monitoring point on each power supply line in the park and the knowledge and experience database, predict whether a short circuit fault will occur on the power supply line in the park and the type of short circuit fault when it occurs.

[0075] Specifically, step 101-3-1 compares the voltage change rate, current change rate, zero-sequence voltage presence and zero-sequence current presence of each phase at each monitoring point on each power supply line in the park with the voltage change rate warning threshold, current change rate warning threshold, zero-sequence current presence and zero-sequence voltage presence of the fault phase on each power supply line in the park under various short-circuit faults.

[0076] Step 101-3-2: If the voltage change rate, current change rate, zero-sequence voltage presence, and zero-sequence current presence of each phase at any monitoring point on the power supply line in the park meet the judgment conditions when compared with the warning thresholds for voltage change rate, current change rate, zero-sequence current presence, and zero-sequence voltage presence of the fault phase under any type of short-circuit fault, then the power supply line in the park is about to experience a short-circuit fault of the corresponding type; otherwise, the power supply line in the park is operating normally.

[0077] Furthermore, the determination condition must simultaneously satisfy the following constraints:

[0078] The voltage change rate of the corresponding phase of the power supply line in the park is greater than the difference between the voltage change rate warning threshold and the preset minimum value of the faulty phase.

[0079] The rate of change of current in the corresponding phase of the power supply line in the park is greater than the difference between the warning threshold for the rate of change of current in the faulty phase and the preset minimum value.

[0080] The zero-sequence voltage and zero-sequence current of the corresponding phases of the power supply lines in the park are consistent with those of the faulty phase.

[0081] For different power supply lines in the park, the current change rate warning threshold and voltage change rate warning threshold for the fault phase under various short-circuit faults are different in the judgment conditions. The current change rate warning threshold and voltage change rate warning threshold for the fault phase under various short-circuit faults on different power supply lines are stored in the knowledge and experience base.

[0082] Step 102: When a short-circuit fault is imminent, fault current phase analysis technology is used to locate the fault point of the power supply line in the park where the short-circuit fault will occur; Step 102 specifically includes:

[0083] Step 102-1: Based on the voltage amplitude and phase angle at each monitoring point on the power supply line where a short circuit fault is about to occur in the park, the fault current phase analysis technology is used to determine the fault direction at each point on the power supply line where a short circuit fault is about to occur in the park.

[0084] Step 102-2: Based on the fault direction of each point on the power supply line in the park where a short circuit fault is about to occur, locate the fault point of the power supply line in the park where a short circuit fault is about to occur.

[0085] The fault direction includes forward faults and reverse faults; a forward fault is when the fault current is in the same direction as the line power flow, and a reverse fault is when the fault current is in the opposite direction to the line power flow.

[0086] Specifically, the fault current phase analysis technique includes:

[0087] Assuming the fault diagram of the power supply line is as follows Figure 2 As shown, assume fault G1 is a forward fault (same as the power flow direction), and the fault current is... The calculation formula is as follows:

[0088]

[0089] In the formula, Let Z be the voltage value at point A, θ be the voltage phase angle at point A, and Z be the voltage value at point A. AG1 θ1 is the impedance value of segment AG1, and θ1 is the phase angle of the impedance of segment AG1.

[0090] right Find the positive derivative:

[0091]

[0092] In the formula, ω is the corresponding angular frequency.

[0093] right Find the negative derivative:

[0094]

[0095] Establish a reference vector to monitor the direction of the fault:

[0096]

[0097] in, This is the reference vector.

[0098] Assume fault G2 is a reverse fault (opposite to the power flow direction), and the fault current... The calculation formula is as follows:

[0099]

[0100] in, Let β be the voltage value at point L, β be the voltage phase angle at point L, and Z be the voltage value at point L. AG2 θ2 is the impedance value of segment AG2, and θ2 is the phase angle of the impedance of segment AG2.

[0101] right Find the positive derivative:

[0102]

[0103] Take the negative derivative with respect to point A:

[0104]

[0105] Establish a reference vector to monitor the direction of the fault:

[0106]

[0107] Based on the above information, the conditions for determining the direction of the short-circuit fault are as follows. And based on the direction of the short-circuit fault, the fault location of the power supply line is achieved.

[0108]

[0109]

[0110] Wherein, △Forward is the condition for determining a forward fault, and △Reverse is the condition for determining a reverse fault.

[0111] Based on the above calculations, after collecting the current data, calculate Δ step by step. If the result is π / 2, the fault is a forward fault; otherwise, it is a reverse fault. If it is a forward fault, the fault is in the same direction as the power flow, that is, the fault occurs at point G1; if it is a reverse fault, the fault is at point G2.

[0112] Among the short circuit faults in the power supply lines of the park, single-phase short circuit faults, two-phase short circuit faults, two-phase ground faults, and three-phase short circuit faults are the four most common types; among them, these four types of short circuit faults can be further distinguished based on symmetry and grounding.

[0113] For example: a three-phase short circuit fault is a symmetrical fault, while a single-phase short circuit fault, a two-phase short circuit fault, and a two-phase-to-ground short circuit fault are asymmetrical short circuit faults.

[0114] Single-phase short circuit faults and two-phase ground short circuit faults are ground short circuit faults, while two-phase short circuit faults and three-phase short circuit faults are ungrounded short circuit faults.

[0115] It is worth mentioning that after a ground fault occurs, the faulty phase will exhibit zero-sequence voltage and zero-sequence current, while the faulty phase will not exhibit zero-sequence voltage and zero-sequence current if an ungrounded short circuit occurs.

[0116] It can be assumed that after four types of short-circuit faults occur in the power supply line, the changes in the current and voltage of the fault phase are different, namely:

[0117] ①When a single-phase short-circuit fault occurs, the amplitude of the fault phase current increases, the amplitude of the voltage decreases, and zero-sequence voltage and zero-sequence current appear.

[0118] ②When a two-phase short-circuit fault occurs, the amplitude of the fault phase current increases, the amplitude of the voltage decreases, and there is no zero-sequence voltage or zero-sequence current;

[0119] ③ When a two-phase ground fault occurs, the amplitude of the fault phase current increases, the amplitude of the voltage decreases, and zero-sequence voltage and zero-sequence current appear;

[0120] ④ When a three-phase short-circuit fault occurs, the amplitude of the fault phase current increases, the amplitude of the voltage decreases, and there is no zero-sequence voltage or zero-sequence current.

[0121] The changes in the fault phase voltage and current of the above-mentioned power supply line are only qualitative analysis results. Using only qualitative analysis as the basis for judging short circuit faults in the power supply line of the park will lead to inaccurate fault prediction. To overcome the above problems, this invention uses a knowledge and experience base established based on the electrical characteristics of historical short circuit faults in the power supply line of the park to assist in short circuit fault prediction.

[0122] The electrical characteristics include: voltage change rate, current change rate, presence of zero-sequence voltage, and presence of zero-sequence current; that is, a knowledge and experience base should be built in advance before step 101.

[0123] The specific construction process of the knowledge and experience base includes:

[0124] Step A-1: ​​Obtain monitoring data of the fault phase at historical moments when various short-circuit faults occurred on each power supply line in the park;

[0125] The monitoring data includes: phase voltage, phase current, phase zero-sequence voltage, and phase zero-sequence current;

[0126] The short circuit fault categories include: phase A short circuit fault, phase B short circuit fault, phase C short circuit fault, phase AB short circuit fault, phase BC short circuit fault, phase AC short circuit fault, phase AB to ground short circuit fault, phase BC to ground short circuit fault, phase AC to ground short circuit fault, and three-phase short circuit fault.

[0127] Step A-2: The monitoring data is processed using the current change rate calculation formula and the voltage change rate calculation formula to obtain the current change rate and voltage change rate of the fault phase at historical moments when various short-circuit faults occur in each power supply line of the park.

[0128] The formula for calculating the rate of change of current is as follows:

[0129]

[0130] In the formula, I is the rate of change of current. d I represents the value after the current amplitude is increased. e τ is the normal operating current value, τ is the free component decay time constant, ΔI is the current rate of change, and Δt is the change time corresponding to the current rate of change.

[0131] The formula for calculating the decay time constant of the free component is as follows:

[0132]

[0133] In the formula, K M K is the short-circuit current impact factor. In actual calculations, K... M The value is generally between 1.8 and 1.9. When the short circuit point is far from the power plant, the value is 1.8; when the short circuit fault occurs on the low-voltage side of the transformer, the value is 1.3; and when the short circuit fault occurs at the synchronous machine terminal, the value is 1.9.

[0134] The formula for calculating the voltage change rate is as follows:

[0135]

[0136] In the formula, U d U represents the value after the voltage amplitude has decreased. e The voltage amplitude is the normal operating voltage, Δu is the change in voltage amplitude, and ΔU% is the rate of voltage change.

[0137] Step A-3: Take the minimum value of the current change rate / voltage change rate of the fault phase at all historical moments when various short-circuit faults occur on each power supply line in the park as the warning threshold for the current change rate / voltage change rate of the fault phase under various short-circuit faults on each power supply line in the park.

[0138] Step A-4: Generate a knowledge and experience base based on the presence of zero-sequence voltage and zero-sequence current of the fault phase when various short-circuit faults occur, as well as the warning thresholds for current change rate and voltage change rate of the fault phase under various short-circuit faults in each power supply line of the park.

[0139] To illustrate in detail, operations were performed for the following scenarios: a single-phase short-circuit fault in power supply line 1, a two-phase short-circuit fault in power supply line 2, a two-phase-to-ground short-circuit fault in power supply line 3, and a three-phase short-circuit fault in power supply line 4. The results are shown in Tables 1, 2, 3, and 4, respectively.

[0140] Table 1

[0141]

[0142] Table 2

[0143]

[0144] Table 3

[0145]

[0146] Table 4

[0147]

[0148] To ensure the accuracy of the calculation of the voltage change rate warning threshold and current change rate warning threshold for the fault phase under various short-circuit faults in the power supply lines of the park, it is necessary to ensure that the selected power supply lines in the park have sufficient power data samples when various short-circuit faults occur. If the samples are insufficient, power data samples of other similar power supply lines (such as power supply lines of the same specifications, located in the same area and with the same service life) when various short-circuit faults occur can be borrowed.

[0149] In an embodiment of the present invention, once a power supply line is identified as being about to experience a short circuit fault in real time, the information is transmitted to the Internet of Things (IoT) management platform. The IoT management platform controls the circuit's on / off state via a smart circuit breaker to locate the fault area of ​​the power supply line. Personnel can then conduct advance inspections of this area to prevent major accidents or losses caused by the short circuit fault.

[0150] After emergency repairs, the following operations can also be performed:

[0151] I: Calculate the rate of change of current and voltage;

[0152] II: Determine whether the short-circuit fault has been recovered based on the calculated values;

[0153] III: If the circuit is restored, the intelligent circuit breaker will close; otherwise, return to step I.

[0154] The formula for calculating the rate of change of current after short-circuit fault recovery is as follows:

[0155]

[0156] Where Ig is the current value after the short-circuit fault is recovered.

[0157] Formula for calculating the rate of voltage change after short-circuit fault recovery:

[0158]

[0159] Wherein, Ug is the voltage amplitude after the short-circuit fault is recovered.

[0160] The method further includes: updating the information in the knowledge and experience base based on an online learning system;

[0161] If a short-circuit fault has just occurred on a power supply line in the park, based on the electrical characteristics of the power supply line when the short-circuit fault occurred, the incremental SVM algorithm is used to correct the voltage change rate warning threshold and current change rate warning threshold of the fault phase under the corresponding type of short-circuit fault in the fault prediction table of the power supply line in the park.

[0162] The objective function of the incremental SVM algorithm is as follows:

[0163]

[0164] Where W is the objective function of the incremental SVM algorithm, α i For the electrical characteristics of the i-th existing short-circuit fault in the power supply line, α j Add a short-circuit fault electrical characteristic, Q, to the power supply line. ij y is the correlation factor between the i-th existing short-circuit fault and the newly added short-circuit fault on the power supply line. i Let b be the fault category of the i-th existing short-circuit fault in the power supply line, and b be a constant.

[0165] Taking the partial derivative of the above equation, we get:

[0166]

[0167] When g is zero, it indicates that the voltage change rate warning threshold and current change rate warning threshold of the fault phase under the same short circuit fault in the power supply line are supported by the electrical characteristics of the newly added short circuit fault in the power supply line; when g is greater than zero or less than zero, it is not supported.

[0168] The update process is as follows: if the voltage change rate of a newly added short-circuit fault in the power supply line is less than the voltage change rate warning threshold of the fault phase under the same type of short-circuit fault in the power supply line, then the voltage change rate warning threshold is updated to the voltage change rate; the update of the current change rate warning threshold is similar.

[0169] This invention predicts short-circuit faults in the power supply lines of the park, but in addition to short-circuit faults, there are also overvoltage, loss faults, etc. in the power supply lines of the park.

[0170] To predict other types of faults in power supply lines, the actual signals of the power supply line (including voltage and current signals) can be correlated with typical actual signals of other types of faults. If the correlation matching result exceeds a threshold, a corresponding type of fault is about to occur in the power supply line of the park. Correlation matching can be performed using the PEN correlation coefficient method, or the following methods:

[0171] Let x(t) and y(t) be two real signals. The difference between the two signals is measured by the following formula:

[0172] δ=x(t)-αy(t+τ)

[0173] Where δ represents the difference between the two signals, x(t) and y(t) are two real signals, α is a constant, and τ is the time delay of the two signals; further, the mean square error criterion is used to measure the difference between the two signals by averaging the difference, and the calculation formula is as follows:

[0174]

[0175] Where W is the mean square value of the difference between the two signals, and T is the time period.

[0176] By differentiating the above equation, and then finding the minimum value of α ( Substituting the minimum value of α into the equation, we obtain the minimum mean square error, which maximizes the similarity between the two signal waveforms.

[0177]

[0178]

[0179] Among them, W min ρ is the minimum mean square value of the difference between the two signals. xy The correlation coefficient is the smaller the mean square value of the difference between two signals, the larger the correlation coefficient, and the stronger the correlation and the more similar the two signals are.

[0180] Furthermore, by discretizing x(t) and y(t), the correlation between the two signals can be analyzed more quickly. The correlation coefficients of x(t) and y(t) after discretization are calculated as follows:

[0181]

[0182] Where, ρ xy Let ρ be the correlation coefficient after discretization of x(t) and y(t), with a value range of [-1, 1]. xy A value of -1 indicates that the two signals are completely negatively correlated; ρ xy A value of 1 indicates that the two signals are perfectly positively correlated; ρ xy When the value is 0, it means that the two signals are completely uncorrelated.

[0183] Example 2:

[0184] To implement the method for diagnosing short-circuit faults in power supply lines within a park, this invention also provides a system for diagnosing short-circuit faults in power supply lines within a park, such as... Figure 3 As shown, it includes:

[0185] The prediction module is used to predict whether a short circuit fault will occur on the power supply lines in the park and the type of short circuit fault when it occurs, based on the monitoring data of each monitoring point on each power supply line in the park and the pre-built knowledge and experience base, using edge computing technology.

[0186] The positioning module is used to locate the fault point of the power supply line in the park that will experience a short circuit when a short circuit fault is about to occur, by employing fault current phase analysis technology.

[0187] The pre-built knowledge and experience base is determined by the electrical characteristics of the fault phase during historical short-circuit faults of each power supply line in the park.

[0188] Specifically, the monitoring data includes: phase voltage, phase current, phase zero-sequence voltage, and phase zero-sequence current;

[0189] The electrical characteristics include: voltage change rate, current change rate, presence of zero-sequence voltage, and presence of zero-sequence current;

[0190] The fault types include: single-phase short-circuit fault, two-phase short-circuit fault, two-phase-to-ground short-circuit fault, and three-phase short-circuit fault;

[0191] The single-phase short-circuit fault includes: phase A short-circuit fault, phase B short-circuit fault and phase C short-circuit fault;

[0192] The two-phase short-circuit faults include: AB phase short-circuit fault, BC phase short-circuit fault and AC phase short-circuit fault;

[0193] The two-phase-to-ground short-circuit fault includes: AB phase-to-ground short-circuit fault, BC phase-to-ground short-circuit fault and AC phase-to-ground short-circuit fault.

[0194] Furthermore, the system also includes a construction module for a pre-built knowledge and experience base, the construction module comprising:

[0195] The acquisition unit is used to acquire the rate of change of current and the rate of change of voltage of each power supply line in the park at the time of occurrence of various short-circuit faults.

[0196] The definition unit is used to take the minimum value of the current change rate / voltage change rate of the fault phase of each power supply line in the park at all times of occurrence of various short circuit faults as the voltage change rate warning threshold / current change rate warning threshold of the fault phase of each power supply line in the park under various short circuit faults.

[0197] The generation unit is used to generate a knowledge and experience base based on the voltage change rate warning threshold, current change rate warning threshold, zero-sequence voltage presence, and zero-sequence current presence of the fault phases of various power supply lines in the park under various short-circuit faults.

[0198] The presence of zero-sequence voltage and zero-sequence current in the fault phase under various short-circuit faults is predetermined.

[0199] Specifically, the voltage change rate of the faulty phase / each phase is calculated based on the normal operating voltage amplitude and the reduced voltage amplitude using the voltage change rate calculation formula;

[0200] The current change rate of the faulty phase / each phase is calculated based on the normal operating current amplitude and the value after the current amplitude is increased, using the current change rate calculation formula.

[0201] Furthermore, the formula for calculating the rate of change of current is as follows:

[0202]

[0203] In the formula, I d I represents the value after the current amplitude is increased. e The normal operating current amplitude is given by τ, where τ is the decay time constant of the free component. The rate of change of current;

[0204] The formula for calculating the decay time constant τ of the free component is as follows:

[0205]

[0206] In the formula, K M This is the short-circuit current impact coefficient;

[0207] The formula for calculating the voltage change rate is as follows:

[0208]

[0209] In the formula, U d U represents the value after the voltage amplitude has decreased. e The voltage amplitude is the normal operating voltage, and ΔU% is the voltage change rate.

[0210] Specifically, the prediction module includes:

[0211] The calculation unit is used to perform edge computing on the monitoring data of each monitoring point on each power supply line in the park, and to determine the electrical characteristics of each phase at each monitoring point on each power supply line in the park.

[0212] The prediction unit is used to predict whether a short circuit fault will occur on the power supply lines of the park and the type of short circuit fault if it occurs, by utilizing the electrical characteristics of each phase at each monitoring point on each power supply line in the park and the knowledge and experience database.

[0213] Specifically, the prediction unit includes:

[0214] The comparison submodule is used to compare the voltage change rate, current change rate, zero-sequence voltage presence and zero-sequence current presence of each phase at each monitoring point on each power supply line in the park with the voltage change rate warning threshold, current change rate warning threshold, zero-sequence current presence and zero-sequence voltage presence of the fault phase on each power supply line in the park under various short-circuit faults.

[0215] The determination submodule is used to determine if the voltage change rate, current change rate, zero-sequence voltage presence, and zero-sequence current presence of each phase at any monitoring point on the power supply line in the park meet the determination conditions when compared with the warning thresholds for voltage change rate, current change rate, zero-sequence current presence, and zero-sequence voltage presence of the fault phase under any type of short-circuit fault. Otherwise, the power supply line in the park is operating normally.

[0216] Furthermore, the determination condition must simultaneously satisfy the following constraints:

[0217] The voltage change rate of the corresponding phase of the power supply line in the park is greater than the difference between the voltage change rate warning threshold and the preset minimum value of the faulty phase.

[0218] The rate of change of current in the corresponding phase of the power supply line in the park is greater than the difference between the warning threshold for the rate of change of current in the faulty phase and the preset minimum value.

[0219] The zero-sequence voltage and zero-sequence current of the corresponding phases of the power supply lines in the park are consistent with those of the faulty phase.

[0220] Specifically, the positioning module includes:

[0221] The analysis unit is used to determine the fault direction at each point on the power supply line in the park that is about to experience a short circuit fault, based on the voltage amplitude and phase angle at each monitoring point on the power supply line in the park.

[0222] The positioning unit is used to locate the fault point of the power supply line in the park that is about to experience a short circuit, based on the fault direction of each point on the power supply line.

[0223] The fault direction includes forward faults and reverse faults; a forward fault is when the fault current is in the same direction as the line power flow, and a reverse fault is when the fault current is in the opposite direction to the line power flow.

[0224] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0225] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0226] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0227] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0228] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions 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. A method for diagnosing short-circuit faults in power supply lines within a park, characterized in that, The method includes: Based on the monitoring data of each monitoring point on each power supply line in the park and the pre-built knowledge and experience database, edge computing technology is used to predict whether a short circuit fault will occur on the power supply line in the park and the type of short circuit fault when it occurs. When a short circuit fault is imminent, fault current phase analysis technology is used to locate the fault point of the power supply line in the park that will experience a short circuit fault. The pre-built knowledge and experience base is determined based on the electrical characteristics of the fault phase during historical short-circuit faults of each power supply line in the park. The construction process of the pre-built knowledge and experience base includes: Obtain the rate of change of current and voltage of each power supply line in the park at the time of occurrence of various short-circuit faults; The minimum value of the current change rate / voltage change rate of each power supply line in the park at all times of occurrence of various short-circuit faults is taken as the warning threshold for voltage change rate / current change rate of each power supply line in the park under various short-circuit faults. A knowledge and experience base is generated based on the warning thresholds for voltage change rate, current change rate, zero-sequence voltage, and zero-sequence current of the fault phases of various power supply lines in the park under various short-circuit faults. The presence of zero-sequence voltage and zero-sequence current in the fault phase under various short-circuit faults is predetermined. Based on monitoring data from monitoring points on each power supply line in the park and a pre-built knowledge and experience base, edge computing technology is used to predict whether a short circuit fault will occur on the park's power supply lines and the type of short circuit fault if it does occur. This includes: Edge computing is performed on the monitoring data of each monitoring point on each power supply line in the park to determine the electrical characteristics of each phase at each monitoring point on each power supply line in the park. By utilizing the electrical characteristics of each phase at each monitoring point on each power supply line in the park and the knowledge and experience database, we can predict whether a short circuit fault will occur on the power supply lines in the park and the type of short circuit fault when it occurs. The method utilizes the electrical characteristics of each phase at each monitoring point on each power supply line in the park and a knowledge and experience database to predict whether a short circuit fault will occur on the park's power supply lines and, if it does, the type of short circuit fault. This includes: The voltage change rate, current change rate, zero-sequence voltage presence, and zero-sequence current presence of each phase at each monitoring point on each power supply line in the park are compared with the voltage change rate warning threshold, current change rate warning threshold, zero-sequence current presence, and zero-sequence voltage presence of the fault phase on each power supply line in the park under various short-circuit faults. If the voltage change rate, current change rate, zero-sequence voltage presence, and zero-sequence current presence of each phase at any monitoring point on the power supply line in the park meet the judgment criteria when compared with the warning thresholds for voltage change rate, current change rate, zero-sequence current presence, and zero-sequence voltage presence of the fault phase under any type of short-circuit fault, then the power supply line in the park is about to experience a short-circuit fault of the corresponding type; otherwise, the power supply line in the park is operating normally.

2. The method as described in claim 1, characterized in that, The monitoring data includes: phase voltage, phase current, phase zero-sequence voltage, and phase zero-sequence current; The electrical characteristics include: voltage change rate, current change rate, presence of zero-sequence voltage, and presence of zero-sequence current; The short-circuit fault types include: single-phase short-circuit fault, two-phase short-circuit fault, two-phase-to-ground short-circuit fault, and three-phase short-circuit fault; The single-phase short-circuit fault includes: phase A short-circuit fault, phase B short-circuit fault and phase C short-circuit fault; The two-phase short-circuit faults include: AB phase short-circuit fault, BC phase short-circuit fault and AC phase short-circuit fault; The two-phase-to-ground short-circuit fault includes: AB phase-to-ground short-circuit fault, BC phase-to-ground short-circuit fault and AC phase-to-ground short-circuit fault.

3. The method as described in claim 1 or 2, characterized in that, The voltage change rate of the faulty phase / each phase is calculated based on the normal operating voltage amplitude and the value after the voltage amplitude is reduced, using the voltage change rate calculation formula. The current change rate of the faulty phase / each phase is calculated based on the normal operating current amplitude and the value after the current amplitude is increased, using the current change rate calculation formula.

4. The method as described in claim 3, characterized in that, The formula for calculating the rate of change of current is as follows: In the formula, This is the value after the current amplitude is increased. This is the normal operating current amplitude. Let be the decay time constant of the free component. The rate of change of current; Among them, the decay time constant of the free component The calculation formula is as follows: In the formula, This is the short-circuit current impact coefficient; The formula for calculating the voltage change rate is as follows: In the formula, This is the value after the voltage amplitude has decreased. This is the normal operating voltage amplitude. This represents the rate of change of voltage.

5. The method as described in claim 1, characterized in that, The determination condition must simultaneously satisfy the following constraints: The voltage change rate of the corresponding phase of the power supply line in the park is greater than the difference between the voltage change rate warning threshold and the preset minimum value of the faulty phase. The rate of change of current in the corresponding phase of the power supply line in the park is greater than the difference between the warning threshold for the rate of change of current in the faulty phase and the preset minimum value. The zero-sequence voltage and zero-sequence current of the corresponding phases of the power supply lines in the park are consistent with those of the faulty phase.

6. The method as described in claim 1, characterized in that, When a short-circuit fault is imminent, fault current phase analysis technology is used to locate the fault point of the power supply line in the park where a short-circuit fault will occur, including: Based on the voltage amplitude and phase angle at each monitoring point on the power supply line that is about to experience a short circuit fault in the park, the fault current phase analysis technology is used to determine the fault direction at each point on the power supply line that is about to experience a short circuit fault in the park. Based on the fault direction at each point on the power supply line in the park that is about to experience a short circuit, locate the fault point of the power supply line in the park that is about to experience a short circuit. The fault direction includes forward faults and reverse faults; a forward fault is when the fault current is in the same direction as the line power flow, and a reverse fault is when the fault current is in the opposite direction to the line power flow.

7. A short-circuit fault diagnosis system for power supply lines in a park, used to implement the method described in claim 1, characterized in that, The system includes: The prediction module is used to predict whether a short circuit fault will occur on the power supply lines in the park and the type of short circuit fault when it occurs, based on the monitoring data of each monitoring point on each power supply line in the park and the pre-built knowledge and experience base, using edge computing technology. The positioning module is used to locate the fault point of the power supply line in the park that will experience a short circuit when a short circuit fault is about to occur, by employing fault current phase analysis technology. The pre-built knowledge and experience base is determined by the electrical characteristics of the fault phase during historical short-circuit faults of each power supply line in the park.

Images