A method and device for detecting grounding wire of power line

Abstract

The present invention discloses a method and device for detecting a grounding wire of a power line, the method comprising: measuring a first impedance of the power line at a first measurement frequency, and measuring the first impedance of the power line at a second measurement frequency; determining the impedance property of the power line according to the first measurement frequency and its corresponding first impedance, and the second measurement frequency and its corresponding second impedance; calculating the third impedance of the power line according to the impedance property of the power line, and calculating the reactance factor according to the third impedance; obtaining the installation state of the grounding wire of the power line according to the reactance factor, the third impedance and the impedance property, and combining the actual measurement conditions. The present invention solves the technical problems of low detection accuracy, insufficient effectiveness, and easy existence of large errors causing detection errors in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid state detection, and in particular to a method and device for detecting a ground wire of a power line. Background Art

[0002] If the power system is powered on with a ground wire or ground knife, the power grid accident caused during power transmission is very serious, which is very likely to cause equipment damage, power grid accidents and even casualties. Therefore, before power is transmitted, how to check whether the ground wire of the power line has been completely removed, whether the ground knife has been fully pulled out, and other installation conditions are key measures to prevent power transmission with a ground wire.

[0003] At present, there is a technical solution in the prior art that uses a clamp meter to apply an induced voltage to a group of ground wires (grounding switches) on the circuit (conductor) to be tested, then measures the current of the circuit, calculates the line impedance according to Ohm's law, and then analyzes whether there is a closed loop in the circuit to determine the ground wire closing (i.e. grounding) state of the circuit to be tested. Since the induced voltage applied to the circuit (conductor) to be tested cannot be directly and accurately measured, and the magnetization curve of the clamp meter core is nonlinear at high frequencies, the amplitude and phase of the primary and secondary voltages cannot be calculated in a linear ratio, so the clamp meter measurement result is the total impedance. When the line impedance is basically resistive, the above detection system can effectively detect the installation status of the ground wire; however, when the reactance (capacitive reactance or inductive reactance) accounts for a large proportion, the reactance of the line has a greater impact on the total impedance of the line, resulting in the above detection system being unable to effectively detect the installation status of the ground wire, and even a large error causing detection errors. Summary of the invention

[0004] The present invention provides a method and device for detecting a grounding wire of a power line, so as to solve the technical problems in the prior art of low detection accuracy, insufficient effectiveness, and easy existence of large errors causing detection errors.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a ground wire detection method for a power line, comprising:

[0006] Measuring a first impedance of the power line at a first measurement frequency, and measuring a second impedance of the power line at a second measurement frequency; wherein the first measurement frequency and the second measurement frequency are different in magnitude;

[0007] Determining an impedance property of the power line according to the first measurement frequency and its corresponding first impedance, and the second measurement frequency and its corresponding second impedance;

[0008] According to the impedance property of the power line, a third impedance of the power line is calculated, and according to the third impedance, a reactance factor is calculated;

[0009] The installation state of the ground wire of the power line is obtained according to the reactance factor, the third impedance and the impedance property.

[0010] As a preferred solution, the measuring of the first impedance of the power line at the first measurement frequency and the measuring of the second impedance of the power line at the second measurement frequency specifically include:

[0011] Measuring the power line with a first clamp meter at a first measurement frequency to obtain a first impedance of the power line;

[0012] Measuring the power line with a second clamp meter at a second measurement frequency to obtain a second impedance of the power line;

[0013] Wherein, the first clamp meter and the second clamp meter are respectively clamped on any group of grounding wires of the power line or the grounding wire of the line grounding switch.

[0014] As a preferred solution, determining the impedance property of the power line according to the first measurement frequency and its corresponding first impedance, and the second measurement frequency and its corresponding second impedance, specifically includes:

[0015] When the first impedance is equal to the second impedance, the impedance property of the power line is resistive;

[0016] When the first impedance is greater than the second impedance and the first measurement frequency is less than the second measurement frequency, or the first impedance is less than the second impedance and the first measurement frequency is greater than the second measurement frequency, the impedance property of the power line is capacitive;

[0017] When the first impedance is smaller than the second impedance and the first measurement frequency is smaller than the second measurement frequency, or the first impedance is larger than the second impedance and the first measurement frequency is larger than the second measurement frequency, the impedance property of the power line is inductive.

[0018] As a preferred solution, after determining the impedance property of the power line, the method further includes:

[0019] When the impedance property of the power line is resistive, a first resistance value and a first reactance value of the power line are calculated according to the first impedance and the second impedance; wherein the first reactance value of the resistive power line is 0;

[0020] When the impedance property of the power line is capacitive, a second resistance value and a second reactance value of the power line are calculated according to the first impedance, the second impedance, the first frequency, the second frequency and the preset power frequency;

[0021] When the impedance property of the power line is inductive, a third resistance value and a third reactance value of the power line are calculated according to the first impedance, the second impedance, the first frequency, the second frequency and a preset power frequency.

[0022] As a preferred solution, the third impedance of the power line is calculated according to the impedance property of the power line, and the reactance factor is calculated according to the third impedance, which specifically includes:

[0023] The third impedance of the power line is calculated according to the resistance value and reactance value corresponding to the impedance property of the power line and the preset power frequency; wherein the resistance value includes: the first resistance value, the second resistance value or the third resistance value, and the reactance value includes the first reactance value, the second reactance value or the third reactance value;

[0024] The reactance factor corresponding to the power line is calculated based on the third impedance and the reactance value corresponding to the impedance property of the power line.

[0025] As a preferred solution, obtaining the installation state of the ground wire of the power line according to the reactance factor, the third impedance and the impedance property specifically includes:

[0026] When the power line is capacitive, the grounding wire installation state of the capacitive power line is obtained according to the reactance factor and the third impedance;

[0027] When the power line is resistive or inductive, the grounding wire installation state of the resistive or inductive power line is obtained according to the third impedance;

[0028] The ground wire installation state includes an uninstalled state and an installed state.

[0029] As a preferred solution, when the power line is capacitive, obtaining the grounding wire installation state of the capacitive power line according to the reactance factor and the third impedance specifically includes:

[0030] When the power line is capacitive, determining a reactance factor corresponding to the power line;

[0031] If the reactance factor is greater than a preset threshold, determining that the ground wire installation state of the capacitive power line is an uninstalled state;

[0032] If the reactance factor is less than a preset threshold value, and the third impedance is greater than a preset resistance value, it is determined that the installation state of the ground wire of the capacitive power circuit is an uninstalled state;

[0033] If the reactance factor is smaller than a preset threshold value, and the third impedance is smaller than a preset resistance value, it is determined that the grounding wire installation state of the capacitive power circuit is a set state.

[0034] As a preferred solution, when the power line is resistive or inductive, determining the installation state of the ground wire of the capacitive power line according to the third impedance specifically includes:

[0035] When the power circuit is resistive or inductive, and the third impedance is greater than a preset resistance value, it is determined that the installation state of the ground wire of the capacitive power circuit is an uninstalled state;

[0036] When the power circuit is resistive or inductive, and the third impedance is less than a preset resistance value, it is determined that the ground wire installation state of the capacitive power circuit is a set state.

[0037] Accordingly, the present invention also provides a ground wire detection device for a power line, comprising: a measurement module, an impedance module, a calculation module and a state module;

[0038] The measuring module is used to measure a first impedance of the power line at a first measuring frequency, and to measure a second impedance of the power line at a second measuring frequency;

[0039] The impedance module is used to determine the impedance property of the power line according to the first measurement frequency and the first impedance corresponding thereto, and the second measurement frequency and the second impedance corresponding thereto;

[0040] The calculation module is used to calculate a third impedance of the power line according to the impedance property of the power line, and calculate a reactance factor according to the third impedance;

[0041] The state module is used to obtain the installation state of the ground wire of the power line according to the reactance factor, the third impedance and the impedance property.

[0042] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0043] The technical solution of the present invention measures the impedance of the power line through the first measurement frequency and the second measurement frequency respectively, and according to the first impedance and the second impedance obtained corresponding to each measurement frequency respectively, it can be determined that the impedance property of the power line belongs to inductive, capacitive or inductive, and then the third impedance of the power line is calculated by the impedance property of the power line, so as to calculate the reactance factor of the power line, so as to determine the degree to which the power line is affected by the reactance, which can effectively reduce the influence of the reactance, and finally combine the impedance property of the power line and the reactance factor and the third impedance, it can accurately and effectively detect whether there is a closed loop in the sensing line, and then obtain the grounding wire installation status of the power line, thereby improving the accuracy of the detection perception of the grounding wire installation status of the power line, avoiding the detection error caused by large errors in measurement when reactance exists, and improving the accuracy and effectiveness of the grounding status detection of the power line. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 : A flow chart of the steps of a ground wire detection method for a power line provided by an embodiment of the present invention;

[0045] Figure 2 : A schematic diagram of the principle of measuring a power line circuit with a clamp meter provided in an embodiment of the present invention;

[0046] Figure 3 : A structural diagram of a grounding wire detection device for a power line provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0048] Embodiment 1

[0049] Please refer to Figure 1 , a method for detecting a ground wire of a power line provided by an embodiment of the present invention, comprising the following steps S101-S104:

[0050] Step S101: measuring a first impedance of a power line at a first measurement frequency, and measuring a second impedance of the power line at a second measurement frequency; wherein the first measurement frequency and the second measurement frequency are different in magnitude.

[0051] It should be noted that the first measurement frequency and the second measurement frequency can be any frequency, and it is only necessary to ensure that the first measurement frequency and the second measurement frequency are different. In this embodiment, the specific values ​​of the first measurement frequency and the second measurement frequency can be set according to the specific application of the actual power line grounding wire detection. Preferably, the value range of the first measurement frequency can be 100Hz-10000Hz, and the value range of the first measurement frequency can be 100Hz-10000Hz. For the measurement of the small resistance power line grounding wire, the first measurement frequency and the second measurement frequency can also be less than 100Hz; for the measurement of the ultra-large-scale power line grounding wire, the first measurement frequency and the second measurement frequency can also be greater than 10000Hz.

[0052] As a preferred solution of this embodiment, measuring the first impedance of the power line at the first measurement frequency, and measuring the second impedance of the power line at the second measurement frequency, specifically includes:

[0053] The power line is measured by a first clamp meter at a first measuring frequency to obtain a first impedance of the power line; the power line is measured by a second clamp meter at a second measuring frequency to obtain a second impedance of the power line; wherein the first clamp meter and the second clamp meter are respectively clamped on any group of grounding wires of the power line or the grounding wire of the line grounding switch, and the first measuring frequency is different from the second measuring frequency.

[0054] In this embodiment, the first clamp meter and the second clamp meter can be a ground resistance clamp meter or a loop resistance tester, and the working principle is to use the clamp meter to apply an induced voltage to a group of ground wires (grounding knife) on the circuit (conductor) to be tested, and then measure the current of the circuit, so as to calculate the circuit impedance according to Ohm's law, as shown in detail. Figure 2 As shown. Since the clamp meter cannot directly measure the induced voltage U applied to the circuit to be tested (it can only obtain the induced voltage output by the clamp meter, but cannot measure the accurate induced voltage applied to the circuit, and the induced voltage applied has loss), and the clamp meter core magnetization curve is nonlinear at high frequency, the amplitude and phase of the primary and secondary voltages cannot be measured in a linear ratio, so the clamp meter measurement result is the total impedance, and it is impossible to determine the impact of the reactance in the power line on the power circuit. For example, in a normal power grid, when the cable line is unloaded (the conductor is not grounded), the line impedance Z is basically the capacitive reactance X C . And the capacitive reactance X C The size is inversely proportional to the measurement frequency, the capacitive reactance X C The size at the power frequency of 50Hz is 1 / 30 of that at the high frequency of 1500Hz. Even if the cable is open-circuited at the high frequency of 1500Hz, its X CThe value may still be very small, and it may even be easily misjudged as a short circuit at the end. For example, the ground capacitance of a 10kV three-core XLPE cable (per kilometer) can reach 0.4μF / km, and the ground capacitance of each kilometer of cable is X C 265Ω If the capacitive reactance of a 3 km cable to ground is X C <100Ω, which will cause the actual test to misjudge that the end is equipped with a ground wire. In addition, power lines with a length of more than 3 kilometers are not uncommon in the power transmission and distribution network. As the cable length increases, the ground capacitance impedance X C It will be further reduced, which shows that the problem of this kind of capacitive reactance misleading is quite prominent.

[0055] In this embodiment, the resistance and reactance of the line are measured by adopting a dual clamp meter method, that is, a first clamp meter and a second clamp meter with different measuring frequencies are used to measure the impedance. The resistance and reactance of the line can be measured at any group of grounding wires in the power line, which can effectively reduce the influence of reactance, and can accurately and effectively detect whether there is a closed loop in the sensing line, and can judge whether the remaining grounding wires of the power line are removed, so as to realize beyond-line-of-sight, full-chain, no-dead-angle, convenient and reliable detection of whether the sensing grounding wire is disconnected, which greatly improves the timeliness and accuracy of the detection perception of the installation status of the grounding wire of the power line, ensures the use of the dual clamp meter method to measure the reactance of the power line and eliminate interference, and realizes accurate and effective judgment of whether the grounding wire of the power line is removed.

[0056] It is understandable that two clamp meters with different measuring frequencies are clamped on any group of ground wires or the grounding lead of the line grounding knife (see Figure 2 ), measure the total impedance Z1 (the result reading of the first clamp meter) and Z2 (the result reading of the second clamp meter) of the power line respectively, and calculate the resistance R and reactance X of the line, then eliminate the influence of the reactance X, and then use the resistance R to effectively detect whether there is a closed loop in the sensing line, so as to accurately determine whether the remaining grounding wires of the power line have been removed.

[0057] Step S102: Determine the impedance properties of the power line according to the first measurement frequency and its corresponding first impedance, and the second measurement frequency and its corresponding second impedance; wherein the impedance properties include capacitance, resistance and inductance.

[0058] By way of example, the impedance properties of the power line can be accurately determined by the measurement frequencies corresponding to the first clamp meter and the second clamp meter, i.e., the first measurement frequency of the first clamp meter and the second measurement frequency of the second clamp meter, and the first impedance measured by the first clamp meter and the second impedance measured by the second clamp meter.

[0059] As a preferred solution of this embodiment, determining the impedance property of the power line according to the first measurement frequency and its corresponding first impedance, and the second measurement frequency and its corresponding second impedance, specifically includes:

[0060] When the first impedance is equal to the second impedance, the impedance property of the power line is resistive; when the first impedance is greater than the second impedance and the first measurement frequency is less than the second measurement frequency, or the first impedance is less than the second impedance and the first measurement frequency is greater than the second measurement frequency, the impedance property of the power line is capacitive; when the first impedance is less than the second impedance and the first measurement frequency is less than the second measurement frequency, or the first impedance is greater than the second impedance and the first measurement frequency is greater than the second measurement frequency, the impedance property of the power line is inductive.

[0061] In this embodiment, when Z1=R=Z2, the impedance property of the power line is resistive. Since there is no reactance in the resistive power line, no matter how much the measurement frequency of the clamp meter is, it will not affect the reactance in the power line (the reactance of the resistive power line is 0), and the resistance of the entire resistive power line is equal to the impedance value measured by the clamp meter, that is, Z1=R=Z2.

[0062] Furthermore, due to the line inductance X L The size is proportional to the measurement frequency, while the capacitive reactance X C The size is inversely proportional to the size of the measurement frequency. For example, the measurement frequency f1 of the first clamp meter is 1500Hz, and the measurement frequency f2 of the second clamp meter is 2000Hz, that is, the frequency f1=1500Hz<f2=2000Hz, and the impedances measured by the first clamp meter and the second clamp meter at the same set of grounding wires of the power line are Z1 and Z2 respectively. Therefore, when f1<f2, Z1>Z2, the impedance property of the power line is capacitive; when f1<f2, Z1<Z2, the impedance property of the power line is inductive; similarly, if the measurement frequency f1 of the first clamp meter is 2000Hz, and the measurement frequency f2 of the second clamp meter is 1500Hz, that is, when f1>f2, Z1>Z2, the impedance property of the power line is inductive; when f1>f2, Z1<Z2, the impedance property of the power line is capacitive.

[0063] As a preferred solution of this embodiment, after determining the impedance property of the power line, the method further includes:

[0064] When the impedance property of the power line is resistive, a first resistance value and a first reactance value of the power line are calculated according to the first impedance and the second impedance; wherein the first reactance value of the resistive power line is 0; when the impedance property of the power line is capacitive, a second resistance value and a second reactance value of the power line are calculated according to the first impedance, the second impedance, the first frequency, the second frequency and the preset power frequency; when the impedance property of the power line is inductive, a third resistance value and a third reactance value of the power line are calculated according to the first impedance, the second impedance, the first frequency, the second frequency and the preset power frequency.

[0065] In this embodiment, when the impedance of the power line is resistive, for any measurement frequency, the relationship between the first impedance, the second impedance and the resistance value of the power line is: Z1=R=Z2. Therefore, the first resistance value of the resistive power line is equal to the first impedance or the second impedance (the first impedance and the second impedance have the same value), and the first reactance value is 0.

[0066] In this embodiment, it is assumed that the measurement frequency f1 of the first clamp meter is 1500 Hz, the measurement frequency f2 of the second clamp meter is 2000 Hz, and the preset power frequency is 50 Hz (the preset power frequency can be set according to the current or voltage frequency when the actual power line is working normally, preferably 50 Hz). When the impedance of the power line is capacitive, Then we have:

[0067]

[0068] Where X 50 It is the reactance value at power frequency 50Hz.

[0069] Thus we get:

[0070] In this embodiment, it is assumed that the measurement frequency f1 of the first clamp meter is 1500 Hz, and the measurement frequency f2 of the second clamp meter is 2000 Hz, and the preset power frequency is 50 Hz. When the impedance of the power line is inductive, Then we have:

[0071]

[0072] Where X 50 It is the reactance value at power frequency 50Hz.

[0073] Thus we get:

[0074] Among them, Z1 and Z2 in the above formula can be applicable to Z1 or Z2 containing information of resistance R and reactance X measured by various methods, including but not limited to Z1 and Z2 can be measured by two independent clamp meters (such as a first clamp meter and a second clamp meter) with different measuring frequencies; or Z1 and Z2 can be measured by a clamp meter integrating two different measuring frequencies (the first clamp meter and the second clamp meter can be the same clamp meter, the difference between the first clamp meter and the second clamp meter is the difference in measuring frequency, and the first clamp meter and the second clamp meter are only used to distinguish the impedance obtained by the same clamp meter at different measuring frequencies). It is mainly that the impedance values ​​Z1 and Z2 of the power line at two different measuring frequencies can be obtained by measuring. For example, the clamp meter set to the first measuring frequency is used as the first clamp meter to measure the first impedance value, and the clamp meter set to the second measuring frequency is used as the second clamp meter to measure the second impedance value, that is, the first impedance of the power line is measured at the first measuring frequency and the first impedance of the power line is measured at the second measuring frequency by the clamp meter, and the clamp meter includes the first clamp meter and the second clamp meter.

[0075] Step S103: according to the impedance property of the power line, a third impedance of the power line is calculated, and according to the third impedance, a reactance factor is calculated.

[0076] As a preferred solution of this embodiment, the third impedance of the power line is calculated according to the impedance property of the power line, and the reactance factor is calculated according to the third impedance, which specifically includes:

[0077] The third impedance of the power line is calculated according to the resistance value and reactance value corresponding to the impedance property of the power line, and the preset power frequency; wherein the resistance value includes: the first resistance value, the second resistance value or the third resistance value, and the reactance value includes the first reactance value, the second reactance value or the third reactance value; the reactance factor corresponding to the power line is calculated according to the third impedance and the reactance value corresponding to the impedance property of the power line.

[0078] In this embodiment, since power lines with different impedance properties have different resistance values ​​and reactance values, the impedance properties of the power lines are determined, and then the third impedance of the current power line can be calculated by the resistance value and reactance value corresponding to the impedance properties, and the preset power frequency, that is, the impedance result measured by the double clamp meter method is converted to the third impedance with a power frequency of 50Hz. Among them, the third impedance Z of the resistive power line 50 =Z1=Z2=R,X 50 =0.

[0079] In this embodiment, the third impedance Z with a power frequency of 50 Hz is 50 , combined with the reactance X with a power frequency of 50Hz 50, so that the reactance influencing factor of the power line can be calculated, that is, the reactance factor It is understandable that the reactance factor The impedance ratio can be converted to any frequency. The frequency converted to the preset power frequency of 50 Hz in this embodiment has the broadest application scenario and is also relatively intuitive.

[0080] Step S104: obtaining the installation state of the ground wire of the power line according to the reactance factor, the third impedance and the impedance property.

[0081] As a preferred solution of this embodiment, obtaining the installation state of the ground wire of the power line according to the reactance factor, the third impedance and the impedance property specifically includes:

[0082] When the power line is capacitive, the grounding wire installation status of the capacitive power line is obtained according to the reactance factor and the third impedance; when the power line is resistive or inductive, the grounding wire installation status of the resistive or inductive power line is obtained according to the third impedance; wherein the grounding wire installation status includes an uninstalled state and an installed state.

[0083] In this embodiment, in a normal state of the power grid, there may be a separate large capacitance (such as an unloaded long cable) between the power line conductor and the ground potential; there may also be a large inductance (such as a parallel high-resistance of a long line), but there will not be a separate small inductance. Therefore, the judgment of the loop state by the inductive impedance is basically the same as that by the resistive impedance. It is only necessary to judge the third impedance to obtain the installation state of the ground wire of the resistive or inductive power line. The capacitive impedance is interfered by the large capacitance of the unloaded long-distance cable line to the ground, so it is necessary to determine the proportion of the reactance to the overall loop impedance through the reactance factor, and then determine the installation state of the ground wire of the capacitive power line.

[0084] As a preferred solution of this embodiment, when the power line is capacitive, obtaining the grounding wire installation state of the capacitive power line according to the reactance factor and the third impedance specifically includes:

[0085] When the power circuit is capacitive, the reactance factor corresponding to the power circuit is determined; if the reactance factor is greater than a preset threshold, the grounding wire installation state of the capacitive power circuit is determined to be an uninstalled state; if the reactance factor is less than the preset threshold, and the third impedance is greater than a preset resistance value, the grounding wire installation state of the capacitive power circuit is determined to be an uninstalled state; if the reactance factor is less than the preset threshold, and the third impedance is less than the preset resistance value, the grounding wire installation state of the capacitive power circuit is determined to be an installed state.

[0086] In this embodiment, when the line is grounded to form a closed loop, according to the actual power maintenance test regulations, the insulation resistance value of the power line to the ground in a normal state should be greater than the megaohm (MΩ) level, specifically, usually greater than 1MΩ; the tower grounding resistance value should be less than the hundred ohms level (<100Ω), specifically, usually less than 30Ω, so in order to consider the error of the clamp meter in impedance measurement, the threshold of the preset resistance value can be taken as the kiloohm (kΩ) level, preferably, the preset resistance value can be 1200Ω. Specifically, the preset resistance value can be combined with the actual engineering requirements, and the on-site environmental temperature, humidity, soil resistivity, and the degree of contamination of the measured line insulators can be measured to reasonably select and set the (preset resistance value) value.

[0087] Furthermore, the preset threshold of the reactance factor is greatly affected by the grounding resistance value of the power line (such as the cable outer sheath, etc.). It can be combined with actual engineering requirements and measured on-site environmental temperature, humidity, soil resistivity and other factors to reasonably select and set the (preset threshold) value.

[0088] In this embodiment, the preset threshold value can be set according to the actual situation. Preferably, the preset threshold value is 0.9 to exclude the interference of large capacitance to the ground of unloaded long-distance cable lines and ensure the influence of reactance on impedance in the overall power line. For example, when the power line is capacitive, that is, X 50 is the capacitive reactance, and When the power line is capacitive, that is, X 50 is the capacitive reactance, and The third impedance Z 50 >1200Ω, the power line is not equipped with a ground wire, that is, the ground wire installation state of the capacitive power line is not installed; when the power line is capacitive, that is, X 50 is the capacitive reactance, and The third impedance Z 50 <1200Ω, the power line is equipped with a grounding wire, and the installation status of the grounding wire of the capacitive power line is already set.

[0089] As a preferred solution of this embodiment, when the power line is resistive or inductive, determining the installation state of the ground wire of the capacitive power line according to the third impedance specifically includes:

[0090] When the power line is resistive or inductive, and the third impedance is greater than a preset resistance value, the grounding wire installation state of the capacitive power line is determined to be an uninstalled state; when the power line is resistive or inductive, and the third impedance is less than a preset resistance value, the grounding wire installation state of the capacitive power line is determined to be an installed state

[0091] In this embodiment, when the power line is resistive or inductive, that is, X 50 is a resistive reactance or an inductive reactance, and the third impedance Z 50 >1200Ω, the power line is not equipped with a grounding wire, that is, the grounding wire installation state of the resistive power line or the inductive power line is not installed; when the power line is resistive or inductive, that is, X 50 is a resistive reactance or an inductive reactance, and the third impedance Z 50 <1200Ω, the power line is equipped with a grounding wire, that is, the installation state of the grounding wire of the resistive power line or the inductive power line is already set.

[0092] It is understandable that by using the double clamp method to measure the line resistance and reactance mode, the line reactance influencing factor is introduced. Measuring the resistance and reactance of any group of grounding wires in the power line can effectively reduce the influence of reactance, accurately and effectively detect whether there is a closed loop in the sensing line, and determine whether the remaining grounding wires of the power line have been removed, achieving beyond-line-of-sight, full-chain, no-dead-angle, convenient and reliable detection of whether the sensing grounding wire is disconnected, greatly improving the timeliness and accuracy of the detection perception of the grounding wire installation status of the power line.

[0093] Implementing the above embodiments has the following effects:

[0094] The technical solution of the present invention measures the impedance of the power line through the first clamp meter and the second clamp meter respectively, and according to the obtained first impedance, second impedance and the measurement frequency corresponding to each clamp meter, it can be determined whether the impedance property of the power line is inductive, capacitive or inductive, and then the third impedance of the power line is calculated by the impedance property of the power line, so as to calculate the reactance factor of the power line, so as to determine the degree to which the power line is affected by the reactance, which can effectively reduce the influence of the reactance, and finally combine the impedance property of the power line and the reactance factor and the third impedance, it can accurately and effectively detect whether there is a closed loop in the sensing line, and then obtain the grounding wire installation status of the power line, thereby improving the detection perception accuracy of the grounding wire installation status of the power line, avoiding the detection error caused by large measurement errors when the reactance exists, and improving the accuracy and effectiveness of the grounding status detection of the power line.

[0095] Embodiment 2

[0096] See also Figure 3 , which is a grounding wire detection device for a power line provided by the present invention, comprising: a measurement module 101, an impedance module 102, a calculation module 103 and a state module 104;

[0097] The measuring module 101 is configured to measure a first impedance of the power line at a first measuring frequency, and to measure the first impedance of the power line at a second measuring frequency;

[0098] The impedance module 102 is used to determine the impedance properties of the power line according to the first measurement frequency and the first impedance corresponding thereto, and the second measurement frequency and the second impedance corresponding thereto; wherein the impedance properties include: resistance, capacitance and inductance;

[0099] The calculation module 103 is used to calculate a third impedance of the power line according to the impedance property of the power line, and calculate a reactance factor according to the third impedance;

[0100] The state module 104 is used to obtain the installation state of the ground wire of the power line according to the reactance factor, the third impedance and the impedance property.

[0101] As a preferred solution, measuring the first impedance of the power line at the first measurement frequency, and measuring the first impedance of the power line at the second measurement frequency, specifically include:

[0102] Measuring the power line with a first clamp meter at a first measurement frequency to obtain a first impedance of the power line;

[0103] Measuring the power line with a second clamp meter at a second measurement frequency to obtain a second impedance of the power line;

[0104] The first clamp meter and the second clamp meter are respectively clamped on any group of grounding wires of the power line or the grounding wire of the line grounding switch, and the first measuring frequency is different from the second measuring frequency.

[0105] As a preferred solution, determining the impedance property of the power line according to the first measurement frequency and its corresponding first impedance, and the second measurement frequency and its corresponding second impedance, specifically includes:

[0106] When the first impedance is equal to the second impedance, the impedance property of the power line is resistive;

[0107] When the first impedance is greater than the second impedance and the first measurement frequency is less than the second measurement frequency, or the first impedance is less than the second impedance and the first measurement frequency is greater than the second measurement frequency, the impedance property of the power line is capacitive;

[0108] When the first impedance is smaller than the second impedance and the first measurement frequency is smaller than the second measurement frequency, or the first impedance is larger than the second impedance and the first measurement frequency is larger than the second measurement frequency, the impedance property of the power line is inductive.

[0109] As a preferred solution, after determining the impedance property of the power line, the method further includes:

[0110] When the impedance property of the power line is resistive, a first resistance value and a first reactance value of the power line are calculated according to the first impedance and the second impedance; wherein the first reactance value of the resistive power line is 0;

[0111] When the impedance property of the power line is capacitive, a second resistance value and a second reactance value of the power line are calculated according to the first impedance, the second impedance, the first frequency, the second frequency and the preset power frequency;

[0112] When the impedance property of the power line is inductive, a third resistance value and a third reactance value of the power line are calculated according to the first impedance, the second impedance, the first frequency, the second frequency and a preset power frequency.

[0113] As a preferred solution, the third impedance of the power line is calculated according to the impedance property of the power line, and the reactance factor is calculated according to the third impedance, which specifically includes:

[0114] The third impedance of the power line is calculated according to the resistance value and reactance value corresponding to the impedance property of the power line and the preset power frequency; wherein the resistance value includes: the first resistance value, the second resistance value or the third resistance value, and the reactance value includes the first reactance value, the second reactance value or the third reactance value;

[0115] The reactance factor corresponding to the power line is calculated based on the third impedance and the reactance value corresponding to the impedance property of the power line.

[0116] As a preferred solution, obtaining the installation state of the ground wire of the power line according to the reactance factor, the third impedance and the impedance property specifically includes:

[0117] When the power line is capacitive, the grounding wire installation state of the capacitive power line is obtained according to the reactance factor and the third impedance;

[0118] When the power line is resistive or inductive, the grounding wire installation state of the resistive or inductive power line is obtained according to the third impedance;

[0119] The ground wire installation state includes an uninstalled state and an installed state.

[0120] As a preferred solution, when the power line is capacitive, obtaining the grounding wire installation state of the capacitive power line according to the reactance factor and the third impedance specifically includes:

[0121] When the power line is capacitive, determining a reactance factor corresponding to the power line;

[0122] If the reactance factor is greater than a preset threshold, determining that the ground wire installation state of the capacitive power line is an uninstalled state;

[0123] If the reactance factor is less than a preset threshold value, and the third impedance is greater than a preset resistance value, it is determined that the installation state of the ground wire of the capacitive power circuit is an uninstalled state;

[0124] If the reactance factor is smaller than a preset threshold value, and the third impedance is smaller than a preset resistance value, it is determined that the grounding wire installation state of the capacitive power circuit is a set state.

[0125] As a preferred solution, when the power line is resistive or inductive, determining the installation state of the ground wire of the capacitive power line according to the third impedance specifically includes:

[0126] When the power circuit is resistive or inductive, and the third impedance is greater than a preset resistance value, it is determined that the installation state of the ground wire of the capacitive power circuit is an uninstalled state;

[0127] When the power line is resistive or inductive, and the third impedance is less than the preset resistance value, it is determined that the grounding wire installation state of the capacitive power line is set to the set state.

[0128] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0129] Implementing the above embodiments has the following effects:

[0130] The technical solution of the present invention measures the impedance of the power line through the first clamp meter and the second clamp meter respectively, and according to the obtained first impedance, second impedance and the measurement frequency corresponding to the clamp meter respectively, it can be determined whether the impedance property of the power line is inductive, capacitive or inductive, and then the third impedance of the power line is calculated by the impedance property of the power line, so as to calculate the reactance factor of the power line, so as to determine the degree to which the power line is affected by the reactance, which can effectively reduce the influence of the reactance, and finally, combined with the impedance property of the power line, the reactance factor and the third impedance, it can accurately and effectively detect whether there is a closed loop in the sensing line, and then obtain the grounding wire installation status of the power line, thereby improving the detection perception accuracy of the grounding wire installation status of the power line, avoiding the detection error caused by large measurement errors when the reactance exists, and improving the accuracy and effectiveness of the grounding status detection of the power line.

[0131] Embodiment 3

[0132] Correspondingly, the present invention also provides a terminal device, comprising: a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein when the processor executes the computer program, the grounding wire detection method for the power line as described in any one of the above embodiments is implemented.

[0133] The terminal device of this embodiment includes: a processor, a memory, and a computer program and a computer instruction stored in the memory and executable on the processor. When the processor executes the computer program, each step in the above-mentioned embodiment 1 is implemented, for example: Figure 1 Alternatively, when the processor executes the computer program, the functions of each module / unit in the above device embodiment, such as the impedance module 102, are implemented.

[0134] Exemplarily, the computer program may be divided into one or more modules / units, and the one or more modules / units are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units may be a series of computer program instruction segments capable of completing specific functions, and the instruction segments are used to describe the execution process of the computer program in the terminal device. For example, the impedance module 102 is used to determine the impedance properties of the power line according to the first measurement frequency and its corresponding first impedance, and the second measurement frequency and its corresponding second impedance; wherein the impedance properties include: resistance, capacitance and inductance.

[0135] The terminal device may be a computing device such as a desktop computer, a notebook, a PDA, and a cloud server. The terminal device may include, but is not limited to, a processor and a memory. Those skilled in the art will appreciate that the schematic diagram is merely an example of a terminal device and does not constitute a limitation on the terminal device. The terminal device may include more or fewer components than shown in the diagram, or may combine certain components, or different components. For example, the terminal device may also include an input / output device, a network access device, a bus, etc.

[0136] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the terminal device, and various interfaces and lines are used to connect various parts of the entire terminal device.

[0137] The memory can be used to store the computer program and / or module, and the processor realizes various functions of the terminal device by running or executing the computer program and / or module stored in the memory, and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one application required for a function, etc.; the data storage area can store data created according to the use of the mobile terminal, etc. In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Med ia Card, SMC), a secure digital (SecureDi gita l, SD) card, a flash card (F l ash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0138] Wherein, if the module / unit integrated in the terminal device is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Wherein, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM, Read-On l yMemory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0139] Embodiment 4

[0140] Correspondingly, the present invention also provides a computer-readable storage medium, which includes a stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute the grounding wire detection method for the power line as described in any one of the above embodiments.

[0141] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for detecting a ground wire of a power line, characterized in that: include: Measuring a first impedance of the power line at a first measurement frequency, and measuring a second impedance of the power line at a second measurement frequency; wherein the first measurement frequency and the second measurement frequency are different in magnitude; Determine the impedance property of the power line according to the first measurement frequency and the first impedance corresponding thereto, and the second measurement frequency and the second impedance corresponding thereto; wherein the impedance property includes: resistance, capacitance and inductance; According to the impedance property of the power line, a third impedance of the power line is calculated, and according to the third impedance, a reactance factor is calculated; according to the resistance value and reactance value corresponding to the impedance property of the power line, and a preset power frequency, the third impedance of the power line is calculated; wherein the resistance value includes: a first resistance value, a second resistance value or a third resistance value, and the reactance value includes a first reactance value, a second reactance value or a third reactance value; according to the third impedance and the reactance value corresponding to the impedance property of the power line, the reactance factor corresponding to the power line is calculated; The installation state of the ground wire of the power line is obtained according to the reactance factor, the third impedance and the impedance property.

2. A method for detecting a ground wire of a power line according to claim 1, characterized in that: The measuring of the first impedance of the power line at the first measurement frequency and the measuring of the second impedance of the power line at the second measurement frequency specifically include: Measuring the power line with a first clamp meter at a first measurement frequency to obtain a first impedance of the power line; Measuring the power line with a second clamp meter at a second measurement frequency to obtain a second impedance of the power line; Wherein, the first clamp meter and the second clamp meter are clamped on any group of grounding wires of the power line or the grounding wire of the line grounding switch.

3. A method for detecting a ground wire of a power line according to claim 2, characterized in that: The determining the impedance property of the power line according to the first measurement frequency and the first impedance corresponding thereto, and the second measurement frequency and the second impedance corresponding thereto, specifically includes: When the first impedance is equal to the second impedance, the impedance property of the power line is resistive; When the first impedance is greater than the second impedance and the first measurement frequency is less than the second measurement frequency, or the first impedance is less than the second impedance and the first measurement frequency is greater than the second measurement frequency, the impedance property of the power line is capacitive; When the first impedance is smaller than the second impedance and the first measurement frequency is smaller than the second measurement frequency, or the first impedance is larger than the second impedance and the first measurement frequency is larger than the second measurement frequency, the impedance property of the power line is inductive.

4. A method for detecting a ground wire of a power line according to any one of claims 1 to 3, characterized in that: After determining the impedance property of the power line, the method further includes: When the impedance property of the power line is resistive, a first resistance value and a first reactance value of the power line are calculated according to the first impedance and the second impedance; wherein the first reactance value of the resistive power line is 0; When the impedance property of the power line is capacitive, a second resistance value and a second reactance value of the power line are calculated according to the first impedance, the second impedance, the first frequency, the second frequency and the preset power frequency; When the impedance property of the power line is inductive, a third resistance value and a third reactance value of the power line are calculated according to the first impedance, the second impedance, the first frequency, the second frequency and the preset power frequency.

5. A method for detecting a ground wire of a power line according to claim 4, characterized in that: The obtaining the installation state of the ground wire of the power line according to the reactance factor, the third impedance and the impedance property specifically includes: When the power line is capacitive, the grounding wire installation state of the capacitive power line is obtained according to the reactance factor and the third impedance; When the power line is resistive or inductive, the grounding wire installation state of the resistive or inductive power line is obtained according to the third impedance; The ground wire installation state includes an uninstalled state and an installed state.

6. A method for detecting a ground wire of a power line according to claim 5, characterized in that: When the power line is capacitive, obtaining the grounding wire installation state of the capacitive power line according to the reactance factor and the third impedance specifically includes: When the power line is capacitive, determining a reactance factor corresponding to the power line; If the reactance factor is greater than a preset threshold, determining that the ground wire installation state of the capacitive power line is an uninstalled state; If the reactance factor is less than a preset threshold value, and the third impedance is greater than a preset resistance value, it is determined that the installation state of the ground wire of the capacitive power circuit is an uninstalled state; If the reactance factor is smaller than a preset threshold value and the third impedance is smaller than a preset resistance value, it is determined that the grounding wire installation state of the capacitive power circuit is a set state.

7. A method for detecting a ground wire of a power line according to claim 5, characterized in that: When the power line is resistive or inductive, determining the installation state of the ground wire of the capacitive power line according to the third impedance specifically includes: When the power circuit is resistive or inductive, and the third impedance is greater than a preset resistance value, it is determined that the installation state of the ground wire of the capacitive power circuit is an uninstalled state; When the power circuit is resistive or inductive, and the third impedance is less than a preset resistance value, it is determined that the ground wire installation state of the capacitive power circuit is a set state.

8. A ground wire detection device for a power line, characterized in that: include: Measurement module, impedance module, calculation module and state module; The measuring module is used to measure the first impedance of the power line at a first measuring frequency, and to measure the first impedance of the power line at a second measuring frequency; The impedance module is used to determine the impedance properties of the power line according to the first measurement frequency and the first impedance corresponding thereto, and the second measurement frequency and the second impedance corresponding thereto; wherein the impedance properties include: resistance, capacitance and inductance; The calculation module is used to calculate the third impedance of the power line according to the impedance property of the power line, and calculate the reactance factor according to the third impedance; calculate the third impedance of the power line according to the resistance value and reactance value corresponding to the impedance property of the power line, and a preset power frequency; wherein the resistance value includes: a first resistance value, a second resistance value or a third resistance value, and the reactance value includes a first reactance value, a second reactance value or a third reactance value; calculate the reactance factor corresponding to the power line according to the third impedance and the reactance value corresponding to the impedance property of the power line; The state module is used to obtain the installation state of the ground wire of the power line according to the reactance factor, the third impedance and the impedance property.

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