Method for monitoring earth insulation resistance

Abstract

The application discloses a ground insulation resistance monitoring method, which can be applied to a ground insulation resistance monitoring device including a first resistance and a second resistance connected in series. In the application, a positive ground insulation resistance and a negative ground insulation resistance can be connected in parallel with the first resistance and the second resistance, and a connection point between the first resistance and the second resistance is grounded. The method can obtain a first voltage of the first resistance and a second voltage of the second resistance. Based on the first voltage and the second voltage, whether the positive ground insulation resistance and the negative ground insulation resistance are abnormal is determined. Based on this, the application can monitor the insulation performance between the positive pole and the ground and the insulation performance between the negative pole and the ground of the power supply of the distribution network DC control loop through the voltages of the two resistances, and identify insulation abnormalities in time. It can be seen that the application converts the distribution network DC insulation performance monitoring into voltage acquisition and processing of two resistances, and dynamically monitors the distribution network DC insulation performance, thereby guaranteeing power supply reliability.

Description

Technical Field

[0001] This application relates to the field of power distribution network technology, and more specifically, to a method for monitoring insulation resistance to ground. Background Technology

[0002] The power distribution network transmits electricity from the transmission network to various user terminals, serving as a bridge between power sources and users, and directly affecting whether users can reliably use electricity. Therefore, the safe and stable operation of the power distribution network is crucial for ensuring people's daily life and production.

[0003] Abnormal DC-to-ground insulation performance is a common fault in the secondary circuits of distribution networks. Over time, this abnormality has become increasingly prevalent, easily causing malfunctions or failures to operate DC-controlled primary switches, leading to power outages and reduced power supply reliability. Therefore, timely identification and handling of abnormal DC-to-ground insulation performance to prevent its impact on power supply reliability has become a key focus for those skilled in the art. Summary of the Invention

[0004] In view of this, this application provides a method for monitoring ground insulation resistance to identify abnormal DC ground insulation resistance.

[0005] To achieve the above objectives, the following solution is proposed:

[0006] A method for monitoring ground insulation resistance is applied to a ground insulation resistance monitoring device, wherein the ground insulation resistance monitoring device includes a first resistor and a second resistor connected in series, the first resistor and the second resistor are connected in parallel with the positive and negative ground insulation resistances of the power supply of the DC control circuit of the distribution network, and the connection point between the first resistor and the second resistor is grounded.

[0007] The method includes:

[0008] Obtain the first voltage of the first resistor and the second voltage of the second resistor;

[0009] Based on the first voltage and the second voltage, determine whether the insulation resistance of the positive electrode to ground and the insulation resistance of the negative electrode to ground are abnormal.

[0010] Optionally, the resistance values ​​of the first resistor and the second resistor are equal;

[0011] Based on the first voltage and the second voltage, determining whether the positive electrode-to-ground insulation resistance and the negative electrode-to-ground insulation resistance are abnormal includes:

[0012] Compare whether the first voltage and the second voltage are equal in magnitude;

[0013] When the first voltage is not equal to the second voltage, the resistance values ​​of the positive electrode to ground insulation resistance and the negative electrode to ground insulation resistance are determined. When the resistance value of the target to ground insulation resistance is less than the preset insulation resistance threshold, it is determined that the target to ground insulation resistance is abnormal. The target to ground insulation resistance is the positive electrode to ground insulation resistance or the negative electrode to ground insulation resistance.

[0014] Optionally, when the first voltage is not equal to the second voltage, determining the resistance values ​​of the positive electrode-to-ground insulation resistance and the negative electrode-to-ground insulation resistance includes:

[0015] When the second voltage is less than the first voltage, the resistance of the positive electrode to ground is determined to be infinite. Based on the first voltage, the second voltage, and the positive electrode to ground insulation resistance, the resistance of the negative electrode to ground insulation resistance is calculated.

[0016] When the first voltage is less than the second voltage, the resistance of the negative electrode to ground is determined to be infinite. Based on the first voltage, the second voltage, and the negative electrode to ground insulation resistance, the resistance of the positive electrode to ground insulation resistance is calculated.

[0017] Optionally, calculating the resistance value of the negative electrode to ground insulation resistance based on the first voltage, the second voltage, and the positive electrode to ground insulation resistance includes:

[0018] Obtain the expression for calculating the negative electrode resistance based on the voltage divider principle;

[0019] Based on the negative electrode resistance calculation expression, the first voltage, the second voltage, and the positive electrode insulation resistance to ground are used to calculate the resistance value of the negative electrode insulation resistance to ground.

[0020] The formula for calculating the negative electrode resistance is as follows:

[0021]

[0022] In the formula, The insulation resistance of the negative electrode to ground; The first voltage; This is the second voltage; The first resistor; This is the second resistor; The positive electrode is the insulation resistance to ground.

[0023] Optionally, the ground insulation resistance monitoring device further includes a third resistor and a fourth resistor with the same resistance value and connected in series. The third resistor and the fourth resistor are connected in parallel with the first resistor and the second resistor. The connection point between the third resistor and the fourth resistor is grounded. A first switch is set between the third resistor and its connection point with the first resistor, and a second switch is set between the fourth resistor and its connection point with the third resistor.

[0024] The step of obtaining the first voltage of the first resistor and the second voltage of the second resistor includes:

[0025] Control the opening and closing of the first switch and the second switch, and obtain the first voltage of the first resistor and the second voltage of the second resistor.

[0026] Optionally, controlling the closing of the first switch and the second switch, and obtaining the first voltage of the first resistor and the second voltage of the second resistor, includes:

[0027] Control the opening and closing states of the first switch and the second switch;

[0028] Obtain the first voltage of the first resistor and the second voltage of the second resistor under different open and closed states.

[0029] Optionally, determining whether the positive electrode-to-ground insulation resistance and the negative electrode-to-ground insulation resistance are abnormal based on the first voltage and the second voltage includes:

[0030] Based on the first voltage and the second voltage under the same open and closed state, determine the functional relationship between the positive electrode insulation resistance to ground and the negative electrode insulation resistance to ground under the corresponding open and closed state;

[0031] Based on the functional relationships under different switching states, determine whether the insulation resistance between the positive electrode and the ground and the insulation resistance between the negative electrode and the ground are abnormal.

[0032] Optionally, obtaining the first voltage of the first resistor and the second voltage of the second resistor under different open / closed states includes:

[0033] Obtain the first target voltage of the first resistor and the second target voltage of the second resistor when the first switch is closed and the second switch is open;

[0034] Obtain the first main voltage of the first resistor and the second main voltage of the second resistor when the second switch is closed and the first switch is open.

[0035] Optionally, determining the functional relationship between the positive-to-ground insulation resistance and the negative-to-ground insulation resistance under the corresponding open / closed states, based on the first and second voltages under the same open / closed state, includes:

[0036] Obtain a preset target voltage divider expression corresponding to the first switch being closed and the second switch being open, and a preset main voltage divider expression corresponding to the second switch being closed and the first switch being open;

[0037] Based on the first resistor, the first target voltage, the second resistor, the second target voltage, the third resistor, and the target voltage divider expression, a first functional relationship corresponding to the first switch being closed and the second switch being open is determined;

[0038] Based on the first resistor, the first main voltage, the second resistor, the second main voltage, the fourth resistor, and the main voltage divider expression, a second functional relationship corresponding to the second switch being closed and the first switch being open is determined.

[0039] Optionally, the target voltage divider expression is as follows:

[0040]

[0041] The main voltage division expression is as follows:

[0042]

[0043] In the formula, The insulation resistance of the negative electrode to ground; The first resistor; This is the second resistor; The insulation resistance between the positive electrode and ground; The first target voltage; The second target voltage; The third resistor; The fourth resistor; The voltage of the first main body; This is the second main voltage.

[0044] A system for monitoring insulation resistance to ground includes a memory and a processor;

[0045] The memory is used to store programs;

[0046] The processor is used to execute the program to implement the various steps of the above-described method for monitoring insulation resistance to ground.

[0047] A readable storage medium having a computer program stored thereon, characterized in that, when the computer program is executed by a processor, it implements the various steps of the above-described method for monitoring insulation resistance to ground.

[0048] As can be seen from the above technical solution, the ground insulation resistance monitoring method provided in this application can be applied to a ground insulation resistance monitoring device including a first resistor and a second resistor connected in series. In this application, the positive and negative ground insulation resistances can be grounded with the first and second resistors, and the connection point between the first and second resistors can be grounded. Therefore, DC ground insulation performance can be indirectly monitored by monitoring the first and second resistors. Based on this, the method can obtain the first voltage of the first resistor and the second voltage of the second resistor. Based on the first and second voltages, it can determine whether the positive and negative ground insulation resistances are abnormal. Therefore, this application can monitor the ground insulation resistance by monitoring the voltage of the first and second resistors. This invention monitors the insulation performance between the positive and negative terminals of the DC control circuit power supply in the distribution network, enabling timely identification and handling of insulation anomalies to ensure the reliability of the power supply. Since the positive-to-ground insulation resistance measures the insulation performance between the positive and negative terminals of the DC control circuit power supply, and vice versa, these resistances reflect the DC-to-ground insulation performance of the DC control circuit power supply. Therefore, this application converts the monitoring of DC insulation performance in the distribution network into the acquisition and processing of voltage values ​​from these two resistors, achieving real-time dynamic monitoring of the DC insulation performance and issuing early warning signals at the early stages of insulation faults. This allows maintenance personnel to take preventative measures, such as repairing or replacing potentially hazardous equipment, preventing further escalation of faults and effectively improving the reliability and stability of the distribution network.

[0049] In addition, since the positive-to-ground insulation resistance and the negative-to-ground insulation resistance are connected in parallel with the first and second resistors and the connection point between the first and second resistors is grounded, the first and second resistors can be connected to the power supply of the DC control circuit of the distribution network. Based on this, this application only needs to connect the first and second resistors to the power supply of the DC control circuit of the distribution network. There is no need to modify the circuit of the distribution network itself, nor is it necessary to introduce complex electronic components or special high-cost monitoring equipment, which reduces the installation and maintenance difficulty of the ground insulation resistance monitoring equipment. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0051] Figure 1 This is a schematic diagram of the structure of a ground insulation resistance monitoring device disclosed in an embodiment of this application;

[0052] Figure 2 This is a flowchart of a method for monitoring ground insulation resistance disclosed in an embodiment of this application;

[0053] Figure 3 This is a schematic diagram of the structure of another ground insulation resistance monitoring device disclosed in the embodiments of this application;

[0054] Figure 1 and Figure 3 The correspondence between the component names and the reference numerals in the attached drawings is as follows:

[0055] 1. First resistor 2. Second resistor 3. Power supply for DC control circuit of distribution network 4. Insulation resistance of positive terminal to ground 5. Insulation resistance of negative terminal to ground 6. Third resistor 7. Fourth resistor 8. First switch 9. Detailed Implementation

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

[0057] The method for monitoring ground insulation resistance of this application will now be described in detail with reference to the accompanying drawings. It should be noted that the orientation of the structures shown in the drawings is set for ease of understanding and does not limit the orientation of the embodiments disclosed in actual implementation. Furthermore, the shape and size of the structure, whether as a whole or in part, shown in the drawings are not limited to the actual shape and size.

[0058] See Figure 1 It can be seen that the ground insulation resistance monitoring device of this application includes a first resistor 1 and a second resistor 2.

[0059] The first resistor 1 and the second resistor 2 can be connected in series, and the first resistor 1 can be connected to the positive terminal of the DC control circuit power supply 3 of the distribution network, while the second resistor 2 can be connected to the negative terminal of the DC control circuit power supply 3 of the distribution network. The connection point between the first resistor 1 and the second resistor 2 can be grounded, which is equivalent to the first resistor 1 and the second resistor 2 being connected in parallel with the positive terminal-to-ground insulation resistance 4 and the negative terminal-to-ground insulation resistance 5 of the DC control circuit power supply 3 of the distribution network. Among them, the positive terminal-to-ground insulation resistance 4 and the negative terminal-to-ground insulation resistance 5 are equivalent resistances that can be used to characterize the ground insulation performance of the DC control circuit power supply 3 of the distribution network.

[0060] The first resistor 1 and the second resistor 2 can be resistors of the same type and with the same resistance value.

[0061] The first resistor 1, the second resistor 2, the positive-to-ground insulation resistance 4, and the negative-to-ground insulation resistance 5 can form a balanced bridge circuit.

[0062] The voltage of power supply 3 in the DC control circuit of the distribution network can be 48V.

[0063] The ground insulation resistance monitoring method of this application can be applied to the aforementioned ground insulation resistance monitoring equipment.

[0064] See Figure 2 The method for monitoring ground insulation resistance in this application includes the following steps:

[0065] Step S1: Obtain the first voltage of the first resistor 1 and the second voltage of the second resistor 2.

[0066] Specifically, the voltage of the first resistor 1 can be used as the first voltage, and the voltage of the second resistor 2 can be used as the second voltage.

[0067] It should be noted that the first voltage refers to the voltage of the first resistor 1, and the second voltage refers to the voltage of the second resistor 2. The voltage values ​​of the first voltage and the second voltage can be the same or different.

[0068] The first voltage and the second voltage are obtained through multiple methods.

[0069] For example, a voltmeter can be installed in the ground insulation resistance monitoring device to obtain the first voltage and the second voltage. An analog-to-digital converter can also be installed in the ground insulation resistance monitoring device to collect the first voltage and the second voltage respectively.

[0070] Step S2: Based on the first voltage and the second voltage, determine whether the positive electrode to ground insulation resistance 4 and the negative electrode to ground insulation resistance 5 are abnormal.

[0071] Specifically, the resistance values ​​of the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5 can be determined based on the first voltage and the second voltage, and it can be determined whether the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5 are abnormal based on their resistance values.

[0072] As can be seen from the above technical solution, the ground insulation resistance monitoring method provided in this application can be applied to a ground insulation resistance monitoring device including a first resistor 1 and a second resistor 2 connected in series. In this application, the positive ground insulation resistance 4 and the negative ground insulation resistance 5 can be grounded to the connection point between the first resistor 1 and the second resistor 2. Therefore, the DC ground insulation performance can be monitored indirectly by monitoring the first resistor 1 and the second resistor 2. Based on this, the method can obtain the first voltage of the first resistor 1 and the second voltage of the second resistor 2. Based on the first voltage and the second voltage, it can determine whether the positive ground insulation resistance 4 and the negative ground insulation resistance 5 are abnormal. Based on this, this application can monitor the first resistor 1 and the second resistor 2. The voltage is used to monitor the insulation performance between the positive and negative terminals of the DC control circuit power supply 3 in the distribution network, enabling timely identification and handling of insulation anomalies to ensure the reliability of the power supply network. Since the positive-to-ground insulation resistance 4 measures the insulation performance between the positive and negative terminals of the DC control circuit power supply 3, and the negative-to-ground insulation resistance 5 measures the insulation performance between the negative and ground terminals, these two resistances reflect the DC-to-ground insulation performance of the DC control circuit power supply. Therefore, this application converts the monitoring of the DC insulation performance of the distribution network into the acquisition and processing of the voltage of these two resistors, achieving real-time dynamic monitoring of the DC insulation performance of the distribution network. This allows for early warning signals to be issued at the early stage of insulation faults. This enables maintenance personnel to take preventative measures in advance, such as repairing or replacing potentially hazardous equipment, preventing further development of faults and effectively improving the reliability and stability of the distribution network.

[0073] In addition, since the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5 are connected in parallel with the first resistor 1 and the second resistor 2, and the connection point between the first resistor 1 and the second resistor 2 is grounded, the first resistor 1 and the second resistor 2 can be connected to the power supply 3 of the distribution network DC control circuit. Based on this, this application only needs to connect the first resistor 1 and the second resistor 2 to the power supply 3 of the distribution network DC control circuit, without modifying the circuit of the distribution network itself, and without introducing complex electronic components or special high-cost monitoring equipment, thus reducing the installation and maintenance difficulty of the ground insulation resistance monitoring equipment.

[0074] Meanwhile, this application can summarize the long-term voltage values ​​of the first voltage and the second voltage, and understand the changing pattern of the insulation performance of the distribution network based on the long-term voltage values ​​of the first voltage and the second voltage, providing a basis for formulating reasonable maintenance plans and equipment replacement strategies.

[0075] In some embodiments of this application, the process of determining whether the positive electrode-to-ground insulation resistance 4 and the negative electrode-to-ground insulation resistance 5 are abnormal based on the first voltage and the second voltage is described in detail below:

[0076] S20. Compare whether the first voltage and the second voltage are equal in magnitude.

[0077] Specifically, since the first resistor 1 and the second resistor 2 are connected in series and have the same resistance value, when the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5 have the same resistance value, the first voltage and the second voltage are equal in magnitude.

[0078] Therefore, the first voltage and the second voltage can be compared to determine whether the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5 have the same resistance value.

[0079] S21. When the first voltage is not equal to the second voltage, determine the resistance values ​​of the positive electrode to ground insulation resistance 4 and the negative electrode to ground insulation resistance 5. When the resistance value of the target to ground insulation resistance is less than the preset insulation resistance threshold, determine that the target to ground insulation resistance is abnormal. The target to ground insulation resistance is the positive electrode to ground insulation resistance 4 or the negative electrode to ground insulation resistance 5.

[0080] Specifically, the magnitudes of the resistance values ​​of the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5 can be determined when the resistance values ​​of the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5 are different.

[0081] From the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5, the resistor with the smaller resistance value can be selected as the target insulation resistance to ground;

[0082] The target insulation resistance to ground can be compared with a preset insulation resistance threshold. If the target insulation resistance to ground is less than the preset insulation resistance threshold, it can be determined that there is an anomaly in the target insulation resistance to ground.

[0083] When both the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5 are greater than the preset insulation resistance threshold, it is determined that there is no abnormality in the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5.

[0084] The insulation resistance threshold can be set according to the ground insulation performance of the corresponding power supply 3 of the DC control circuit of the distribution network.

[0085] As can be seen from the above technical solution, this embodiment provides an optional method for determining whether the positive electrode to ground insulation resistance 4 and the negative electrode to ground insulation resistance 5 are abnormal based on the first voltage and the second voltage. The above method can determine the abnormal insulation performance when the insulation resistance is small.

[0086] In some embodiments of this application, the process of determining the resistance values ​​of the positive electrode-to-ground insulation resistance 4 and the negative electrode-to-ground insulation resistance 5 in step S21 when the first voltage is not equal to the second voltage is described in detail. The steps are as follows:

[0087] S210. When the second voltage is less than the first voltage, the resistance of the positive electrode to ground insulation resistance 4 is determined to be infinite. Based on the first voltage, the second voltage and the positive electrode to ground insulation resistance 4, the resistance of the negative electrode to ground insulation resistance 5 is calculated.

[0088] Specifically, when the second voltage is less than the first voltage, there may be a grounding fault at the negative end of the power supply 3 of the DC control circuit of the distribution network. Therefore, the resistance value of the positive-to-ground insulation resistance 4 can be set to infinity, and the resistance value of the negative-to-ground insulation resistance 5 can be calculated based on the first voltage, the second voltage and the positive-to-ground insulation resistance 4.

[0089] S211. When the first voltage is less than the second voltage, the resistance of the negative electrode to ground insulation resistance 5 is determined to be infinite. Based on the first voltage, the second voltage and the negative electrode to ground insulation resistance 5, the resistance of the positive electrode to ground insulation resistance 4 is calculated.

[0090] Specifically, when the first voltage is less than the second voltage, there may be a grounding fault at the positive terminal of the power supply 3 of the DC control circuit of the distribution network. Therefore, the resistance value of the negative terminal to ground insulation resistance 5 can be set to infinity, and the resistance value of the positive terminal to ground insulation resistance 4 can be calculated based on the first voltage, the second voltage and the negative terminal to ground insulation resistance 5.

[0091] As can be seen from the above technical solution, this embodiment provides an optional method for determining the resistance values ​​of the positive electrode to ground insulation resistance 4 and the negative electrode to ground insulation resistance 5 when the first voltage is not equal to the second voltage. Through the above method, different methods can be used to determine the resistance values ​​according to different single-ended grounding faults, which further ensures the accuracy of the resistance values ​​of the negative electrode to ground insulation resistance 5 and the positive electrode to ground insulation resistance 4 calculated in this application.

[0092] In some embodiments of this application, the process of calculating the resistance value of the negative electrode to ground insulation resistance 5 based on the first voltage, the second voltage, and the positive electrode to ground insulation resistance 4 in step S210 is described in detail as follows:

[0093] S2100, Obtain the calculation expression for the negative electrode resistance based on the voltage divider principle.

[0094] Specifically, the expression for calculating the negative electrode resistance is as follows:

[0095]

[0096] In the formula, The insulation resistance of the negative electrode to ground is 5. The first voltage; This is the second voltage; The first resistor is 1; The second resistor is 2; The insulation resistance 4 between the positive electrode and ground.

[0097] S2101. Based on the negative electrode resistance calculation expression, the first voltage, the second voltage, and the positive electrode-to-ground insulation resistance 4, calculate the resistance value of the negative electrode-to-ground insulation resistance 5.

[0098] Specifically, the first voltage, the second voltage, and the infinitely large positive-to-ground insulation resistance 4 can be substituted into the negative-to-ground resistance calculation expression to calculate the resistance value of the negative-to-ground insulation resistance 5.

[0099] As can be seen from the above technical solution, this embodiment provides an optional method for calculating the insulation resistance 5 of the negative electrode to ground. The above method can better calculate the insulation resistance 5 of the negative electrode to ground, thereby better monitoring of abnormal insulation performance.

[0100] In some embodiments of this application, the process of calculating the resistance value of the positive electrode to ground insulation resistance 4 based on the first voltage, the second voltage, and the negative electrode to ground insulation resistance 5 in step S211 is described in detail as follows:

[0101] S2110. Obtain the calculation expression for the positive electrode resistance based on the voltage divider principle.

[0102] Specifically, the expression for calculating the positive electrode resistance can be as follows:

[0103]

[0104] S2111. Based on the positive electrode resistance calculation expression, the first voltage, the second voltage, and the negative electrode-to-ground insulation resistance 5, calculate the resistance value of the positive electrode-to-ground insulation resistance 4.

[0105] Specifically, the first voltage, the second voltage, and the negative electrode-to-ground insulation resistance 5 can be substituted into the positive electrode resistance calculation expression to calculate the resistance value of the positive electrode-to-ground insulation resistance 4.

[0106] As can be seen from the above technical solution, this embodiment provides an optional method for calculating the resistance value of the positive electrode to ground insulation resistance 4. The above method can better calculate the resistance value of the positive electrode to ground insulation resistance 4 and further improve the accuracy of the resistance value of the positive electrode to ground insulation resistance 4.

[0107] Based on this, this application can be constructed as follows: Figure 1 The balanced bridge circuit shown is used to monitor whether the insulation resistance 4 of the positive terminal to ground and the insulation resistance 5 of the negative terminal to ground are abnormal.

[0108] The balanced bridge circuit ensures the relative stability and balance of the DC positive and negative voltages to ground, and has a fast detection speed, thus allowing for long-term use for rapid insulation testing. Specifically, it can perform the following steps in real time: acquire the first voltage of the first resistor 1 and the second voltage of the second resistor 2; compare whether the first voltage and the second voltage are equal; when the second voltage is less than the first voltage, determine that the resistance of the positive terminal to ground insulation resistor 4 is infinite; based on the first voltage, the second voltage, and the positive terminal to ground insulation resistor 4, calculate the resistance of the negative terminal to ground insulation resistor 5; when the first voltage is less than the second voltage, determine that the resistance of the negative terminal to ground insulation resistor 5 is infinite; based on the first voltage, the second voltage, and the negative terminal to ground insulation resistor 5, calculate the resistance of the positive terminal to ground insulation resistor 4.

[0109] In some embodiments of this application, the ground insulation resistance monitoring device may further include a third resistor 6 and a fourth resistor 7 with the same resistance value connected in series. The third resistor 6 and the fourth resistor 7 are connected in parallel with the first resistor 1 and the second resistor 2. The connection point between the third resistor 6 and the fourth resistor 7 is grounded. Since the first resistor 1 and the second resistor 2 are connected in parallel with the positive ground insulation resistance 4 and the negative ground insulation resistance 5, the third resistor 6 and the fourth resistor 7 are also connected in parallel with the positive ground insulation resistance 4 and the negative ground insulation resistance 5. Figure 3 As shown.

[0110] See Figure 3 It can be seen that the ground insulation resistance monitoring device may also include a first switch 8 and a second switch 9.

[0111] The first switch 8 can be set between the third resistor 6 and the first connection point, which can be the connection point between the third resistor 6 and the first resistor 1.

[0112] The second switch 9 can be positioned between the fourth resistor 7 and the second connection point, which can be the connection point between the fourth resistor 7 and the third resistor 6. Therefore, the opening and closing of the first switch 8 and the second switch 9 can affect the balance state of the circuit, and different opening and closing states can correspond to different balance states.

[0113] Therefore, the first voltage and the second voltage under different equilibrium states can be collected. Next, the collection process will be described, that is, the process of obtaining the first voltage of the first resistor 1 and the second voltage of the second resistor 2 in step S1 will be explained in detail. The steps are as follows:

[0114] S10. Control the opening and closing of the first switch 8 and the second switch 9, and obtain the first voltage of the first resistor 1 and the second voltage of the second resistor 2.

[0115] Specifically, the opening and closing of the first switch 8 and the second switch 9 can be controlled, so that the first switch 8 and the second switch 9 are in different open and closed states, and the first voltage and the second voltage can be collected.

[0116] As can be seen from the above technical solution, this embodiment provides an optional method for collecting the first voltage and the second voltage. Through the above method, the first voltage and the second voltage under different opening and closing states can be collected, so as to better complete the monitoring of DC to ground insulation performance.

[0117] In some embodiments of this application, the process of step S10, controlling the opening and closing of the first switch 8 and the second switch 9, and obtaining the first voltage of the first resistor 1 and the second voltage of the second resistor 2, is described in detail as follows:

[0118] S100: Control the opening and closing states of the first switch 8 and the second switch 9.

[0119] Specifically, the opening or closing of the first switch 8 and the second switch 9 can be controlled to form a variety of open and closed states.

[0120] S101. Obtain the first voltage of the first resistor 1 and the second voltage of the second resistor 2 under different open and closed states.

[0121] Specifically, the first voltage and the second voltage under different opening and closing states can be obtained.

[0122] As can be seen from the above technical solution, this embodiment provides an optional method for controlling the opening and closing of the first switch 8 and the second switch 9, and obtaining the first voltage and the second voltage. Through the above method, the first voltage and the second voltage under different equilibrium states can be better collected.

[0123] In some embodiments of this application, the process of determining whether the positive electrode-to-ground insulation resistance 4 and the negative electrode-to-ground insulation resistance 5 are abnormal based on the first voltage and the second voltage is described in detail below:

[0124] S20. Based on the first voltage and the second voltage under the same open / closed state, determine the functional relationship between the positive electrode to ground insulation resistance 4 and the negative electrode to ground insulation resistance 5 under the corresponding open / closed state.

[0125] Specifically, the voltage divider principle can be used to generate a functional relationship between the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5 under the same open and closed state, based on the first voltage and the second voltage under the same open and closed state.

[0126] S21. Based on the functional relationships under different switching states, determine whether the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5 are abnormal.

[0127] Specifically, the resistance values ​​of the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5 can be determined by combining various functional relationships. The resistance values ​​of the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5 are then compared with the preset insulation resistance threshold. When the resistance values ​​of the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5 both exceed the insulation resistance threshold, it is determined that the DC-to-ground insulation resistance of the distribution network is in a normal state.

[0128] When the resistance of the positive electrode to ground insulation resistance 4 is less than the insulation resistance threshold, the positive electrode to ground insulation resistance 4 is determined to be abnormal.

[0129] When the insulation resistance 5 between the negative pole and ground is less than the insulation resistance threshold, the insulation resistance 5 between the negative pole and ground is determined to be abnormal.

[0130] As can be seen from the above technical solution, this embodiment provides another optional method to determine whether the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5 are abnormal based on the first voltage and the second voltage. By combining the above method with different balance states, it is possible to determine whether the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5 are abnormal, and to better monitor the DC-to-ground insulation performance of the distribution network.

[0131] Based on this, this application can be constructed as follows Figure 3 The unbalanced bridge circuit shown enables abnormal monitoring of the positive-to-ground insulation resistance 4 and the negative-to-ground insulation resistance 5.

[0132] Considering that the unbalanced bridge circuit will cause voltage fluctuations between the positive and negative electrodes and ground when it is put into operation, and that the detection speed is relatively slow, the unbalanced bridge method can be used for precise insulation detection. That is, the following steps can be executed at regular intervals: control the opening and closing states of the first switch 8 and the second switch 9; obtain the first voltage of the first resistor 1 and the second voltage of the second resistor 2 under different opening and closing states; based on the first voltage and the second voltage under the same opening and closing state, determine the functional relationship between the positive electrode to ground insulation resistance 4 and the negative electrode to ground insulation resistance 5 under the corresponding opening and closing states; based on the various functional relationships under different switching states, determine whether the positive electrode to ground insulation resistance 4 and the negative electrode to ground insulation resistance 5 are abnormal.

[0133] In some embodiments of this application, the process of step S101, obtaining the first voltage of the first resistor 1 and the second voltage of the second resistor 2 under different open and closed states, is described in detail as follows:

[0134] S1010: Obtain the first target voltage of the first resistor 1 and the second target voltage of the second resistor 2 when the first switch 8 is closed and the second switch 9 is open.

[0135] Specifically, the voltage of the first resistor 1 can be obtained when the first switch 8 is closed and the second switch 9 is open, and the voltage of the first resistor 1 when the first switch 8 is closed and the second switch 9 is open can be used as the first target voltage;

[0136] The voltage of the second resistor 2 can be obtained when the first switch 8 is closed and the second switch 9 is open, and the voltage of the second resistor 2 when the first switch 8 is closed and the second switch 9 is open can be used as the second target voltage.

[0137] S1011. Obtain the first main voltage of the first resistor 1 and the second main voltage of the second resistor 2 when the second switch 9 is closed and the first switch 8 is open.

[0138] Specifically, when the second switch 9 is closed and the first switch 8 is open, the voltage of the first resistor 1 can be obtained, and the voltage of the first resistor 1 when the second switch 9 is closed and the first switch 8 is open can be used as the first main voltage;

[0139] The voltage of the second resistor 2 can be obtained when the second switch 9 is closed and the first switch 8 is open, and the voltage of the second resistor 2 when the second switch 9 is closed and the first switch 8 is open can be used as the second main voltage.

[0140] As can be seen from the above technical solution, this embodiment provides an optional method for obtaining the first voltage of the first resistor 1 and the second voltage of the second resistor 2 under different open and closed states. Through the above method, the voltages of the first resistor 1 and the second resistor 2 under different open and closed states of the first switch 8 and the second switch 9 can be collected.

[0141] In some embodiments of this application, the process of determining the functional relationship between the positive electrode-to-ground insulation resistance 4 and the negative electrode-to-ground insulation resistance 5 in the corresponding open / closed state based on the first voltage and the second voltage in the same open / closed state is described in detail. The steps are as follows:

[0142] S200: Obtain a preset target voltage divider expression corresponding to the first switch 8 being closed and the second switch 9 being open, and a preset main voltage divider expression corresponding to the second switch 9 being closed and the first switch 8 being open.

[0143] Specifically, the target voltage division expression and the main voltage division expression can be obtained.

[0144] S201. Based on the first resistor 1, the first target voltage, the second resistor 2, the second target voltage, the third resistor 6, and the target voltage divider expression, determine a first functional relationship corresponding to the first switch 8 being closed and the second switch 9 being open.

[0145] Specifically, the first resistor 1, the first target voltage, the second resistor 2, the second target voltage, and the third resistor 6 can be substituted into the target voltage divider expression to calculate the first functional relationship between the positive electrode to ground insulation resistance 4 and the negative electrode to ground insulation resistance 5.

[0146] S202. Based on the first resistor 1, the first main voltage, the second resistor 2, the second main voltage, the fourth resistor 7, and the main voltage divider expression, determine the second functional relationship corresponding to the second switch 9 being closed and the first switch 8 being open.

[0147] Specifically, the first resistor 1, the first main voltage, the second resistor 2, the second main voltage, and the fourth resistor 7 can be substituted into the main voltage divider expression to calculate the second functional relationship between the positive electrode to ground insulation resistance 4 and the negative electrode to ground insulation resistance 5.

[0148] As can be seen from the above technical solution, this embodiment provides an optional way to determine the functional relationship. The functional relationship of different equilibrium states can be determined by the above method, thereby improving the accuracy of the calculated resistance values ​​of the positive electrode to ground insulation resistance 4 and the negative electrode to ground insulation resistance 5.

[0149] Furthermore, the target voltage divider expression is as follows:

[0150]

[0151] The main voltage division expression is as follows:

[0152]

[0153] In the formula, The insulation resistance of the negative electrode to ground is 5. The first resistor is 1; The second resistor is 2; The insulation resistance of the positive electrode to ground is 4. The first target voltage; The second target voltage; The third resistor is 6; The fourth resistor is 7; The voltage of the first main body; This is the second main voltage.

[0154] In some embodiments of this application, the ground insulation resistance monitoring device may further include an anomaly monitoring module;

[0155] The anomaly monitoring module can be used to obtain the first voltage of the first resistor 1 and the second voltage of the second resistor 2; based on the first voltage and the second voltage, determine whether the positive electrode to ground insulation resistance 4 and the negative electrode to ground insulation resistance 5 are abnormal.

[0156] Optionally, the refined and extended functions of the anomaly monitoring module can be found in the description above.

[0157] By using a balanced bridge circuit to measure the resistance of positive and negative terminals when single-terminal grounding occurs, and an unbalanced bridge circuit to measure the resistance of positive and negative terminals when double-terminal grounding occurs, grounding problems in the DC circuit of the secondary circuit of the entire distribution network can be detected. This solves the technical problem that the distribution network automation terminal cannot provide early warning of DC grounding defects, and moves the risk of switchgear malfunction and failure to operate forward, allowing for early detection and resolution of hidden dangers, which can significantly improve power supply reliability.

[0158] This application embodiment also provides a readable storage medium that can store a program suitable for execution by a processor, the program being used for:

[0159] Obtain the first voltage of the first resistor and the second voltage of the second resistor;

[0160] Based on the first voltage and the second voltage, determine whether the insulation resistance of the positive electrode to ground and the insulation resistance of the negative electrode to ground are abnormal.

[0161] Optionally, the refined and extended functions of the program can be referred to the above description.

[0162] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0163] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0164] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. The various embodiments of this application can be combined with each other. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for monitoring insulation resistance to ground, characterized in that, An equipment for monitoring insulation resistance to ground is used. The equipment includes a first resistor and a second resistor connected in series. The first resistor and the second resistor are connected in parallel with the positive and negative insulation resistances to ground of the DC control circuit power supply of the distribution network. The connection point between the first resistor and the second resistor is grounded. The resistance values ​​of the first resistor and the second resistor are equal. The method includes: Obtain the first voltage of the first resistor and the second voltage of the second resistor; Compare whether the first voltage and the second voltage are equal in magnitude; When the first voltage is not equal to the second voltage, the resistance values ​​of the positive electrode to ground insulation resistance and the negative electrode to ground insulation resistance are determined, and when the resistance value of the target to ground insulation resistance is less than the preset insulation resistance threshold, it is determined that the target to ground insulation resistance is abnormal, wherein the target to ground insulation resistance is the positive electrode to ground insulation resistance or the negative electrode to ground insulation resistance. When the first voltage is not equal to the second voltage, determining the resistance values ​​of the positive electrode-to-ground insulation resistance and the negative electrode-to-ground insulation resistance includes: When the second voltage is less than the first voltage, the resistance of the positive electrode to ground is determined to be infinite. Based on the first voltage, the second voltage, and the positive electrode to ground insulation resistance, the resistance of the negative electrode to ground insulation resistance is calculated. When the first voltage is less than the second voltage, the resistance of the negative electrode to ground is determined to be infinite. Based on the first voltage, the second voltage, and the negative electrode to ground insulation resistance, the resistance of the positive electrode to ground insulation resistance is calculated. The calculation of the insulation resistance of the negative terminal to ground based on the first voltage, the second voltage, and the insulation resistance of the positive terminal to ground includes: Obtain the expression for calculating the negative electrode resistance based on the voltage divider principle; Based on the negative electrode resistance calculation expression, the first voltage, the second voltage, and the positive electrode insulation resistance to ground are used to calculate the resistance value of the negative electrode insulation resistance to ground. The formula for calculating the negative electrode resistance is as follows: In the formula, The insulation resistance of the negative electrode to ground; The first voltage; This is the second voltage; The first resistor; This is the second resistor; The positive electrode is the insulation resistance to ground.

2. The method for monitoring ground insulation resistance according to claim 1, characterized in that, The ground insulation resistance monitoring device also includes a third resistor and a fourth resistor with the same resistance value and connected in series. The third resistor and the fourth resistor are connected in parallel with the first resistor and the second resistor. The connection point between the third resistor and the fourth resistor is grounded. A first switch is set between the third resistor and its connection point with the first resistor. A second switch is set between the fourth resistor and its connection point with the third resistor. The step of obtaining the first voltage of the first resistor and the second voltage of the second resistor includes: Control the opening and closing of the first switch and the second switch, and obtain the first voltage of the first resistor and the second voltage of the second resistor.

3. The method for monitoring ground insulation resistance according to claim 2, characterized in that, The step of controlling the closing of the first switch and the second switch, and obtaining the first voltage of the first resistor and the second voltage of the second resistor, includes: Control the opening and closing states of the first switch and the second switch; Obtain the first voltage of the first resistor and the second voltage of the second resistor under different open and closed states.

4. The method for monitoring ground insulation resistance according to claim 3, characterized in that, The step of determining whether the insulation resistance of the positive electrode to ground and the insulation resistance of the negative electrode to ground are abnormal based on the first voltage and the second voltage includes: Based on the first voltage and the second voltage under the same open and closed state, determine the functional relationship between the positive electrode insulation resistance to ground and the negative electrode insulation resistance to ground under the corresponding open and closed state; Based on the functional relationships under different switching states, determine whether the insulation resistance between the positive electrode and the ground and the insulation resistance between the negative electrode and the ground are abnormal.

5. The method for monitoring ground insulation resistance according to claim 4, characterized in that, The step of obtaining the first voltage of the first resistor and the second voltage of the second resistor under different open / closed states includes: Obtain the first target voltage of the first resistor and the second target voltage of the second resistor when the first switch is closed and the second switch is open; Obtain the first main voltage of the first resistor and the second main voltage of the second resistor when the second switch is closed and the first switch is open.

6. The method for monitoring ground insulation resistance according to claim 5, characterized in that, The determination of the functional relationship between the positive-to-ground insulation resistance and the negative-to-ground insulation resistance under the same open / closed state, based on the first and second voltages under the same open / closed state, includes: Obtain a preset target voltage divider expression corresponding to the first switch being closed and the second switch being open, and a preset main voltage divider expression corresponding to the second switch being closed and the first switch being open; Based on the first resistor, the first target voltage, the second resistor, the second target voltage, the third resistor, and the target voltage divider expression, a first functional relationship corresponding to the first switch being closed and the second switch being open is determined; Based on the first resistor, the first main voltage, the second resistor, the second main voltage, the fourth resistor, and the main voltage divider expression, a second functional relationship corresponding to the second switch being closed and the first switch being open is determined.

7. The method for monitoring ground insulation resistance according to claim 6, characterized in that, The target voltage divider expression is as follows: The main voltage division expression is as follows: In the formula, The insulation resistance of the negative electrode to ground; The first resistor; This is the second resistor; The insulation resistance between the positive electrode and ground; The first target voltage; The second target voltage; The third resistor; The fourth resistor; The voltage of the first main body; This is the second main voltage.

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