CN113589192A - Dual-frequency injection insulation monitoring method, device and system and storage medium - Google Patents
Dual-frequency injection insulation monitoring method, device and system and storage medium Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 48
- 238000012544 monitoring process Methods 0.000 title claims abstract description 36
- 238000005070 sampling Methods 0.000 claims description 14
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
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Abstract
The invention relates to the technical field of insulation monitoring, and provides a double-frequency injection insulation monitoring method, a device, a system and a storage medium, wherein the method comprises the steps of determining a target insulation resistance value and a target distribution capacitance value; when the target insulation resistance value is higher than the first resistance threshold value, the amplitude of the first frequency component and the amplitude of the second frequency component are increased to a first preset value; when the target insulation resistance value is lower than a second resistance threshold value, reducing the amplitude of the first frequency component and the amplitude of the second frequency component to a second preset value; the first resistance threshold is higher than the second resistance threshold; when the target distribution capacitance value is higher than the first capacitance threshold value, reducing the frequency value of the first frequency component and the frequency value of the second frequency component by a first target multiple; when the target distribution capacitance value is higher than the second capacitance threshold value, the frequency value of the first frequency component and the frequency value of the second frequency component are increased by the first target multiple, so that the problem of low measurement accuracy of the existing monitoring method can be solved.
Description
Technical Field
The invention relates to the technical field of insulation monitoring, in particular to a method, a device and a system for double-frequency injection insulation monitoring and a storage medium.
Background
The heating pipes of the nuclear reactor voltage stabilizer are large in quantity, and the heating pipes of the voltage stabilizer are frequently replaced and seriously damaged easily due to high temperature, large current, heating loss and the like which are necessary in engineering environment. In view of the serious influence caused by the damage of the voltage stabilizer, the online insulation resistance monitoring needs to be accurately and quickly carried out so as to early warn.
At present, when the insulation resistance is larger than 500k ohm, the current of an injection source circuit is small, so that the measurement error of the insulation resistance is increased slowly, when the insulation resistance reaches 1M ohm, the error reaches or even exceeds 10%, and when the error is larger, the measurement is inaccurate. The dual-frequency injection method is theoretically not affected by the distributed capacitance, but actually when the distributed capacitance is too large, the current in the sampling loop is mainly a capacitance component, and the separated resistance component is very small, so that the measurement error is large.
It can be seen that the existing monitoring method has the problem of low measurement accuracy.
Disclosure of Invention
The invention provides a double-frequency injection insulation monitoring method, a device, a system and a storage medium, which aim to solve the problem of low measurement precision of the existing monitoring method.
In order to achieve the purpose, the invention is realized by the following technical scheme:
in a first aspect, the present invention provides a dual-frequency injection insulation monitoring method, applied to an insulation monitoring device, including:
determining a target insulation resistance value and a target distribution capacitance value;
when the target insulation resistance value is higher than a first resistance threshold value, the amplitude of the first frequency component and the amplitude of the second frequency component are increased to a first preset value;
when the target insulation resistance value is lower than a second resistance threshold value, reducing the amplitude of the first frequency component and the amplitude of the second frequency component to a second preset value; the first resistance threshold is higher than the second resistance threshold;
when the target distribution capacitance value is higher than a first capacitance threshold value, reducing the frequency value of the first frequency component and the frequency value of the second frequency component by a first target multiple;
and when the target distribution capacitance value is higher than a second capacitance threshold value, increasing the frequency value of the first frequency component and the frequency value of the second frequency component by a first target multiple, wherein the first capacitance threshold value is larger than the second capacitance threshold value.
Optionally, when the target insulation resistance value is higher than the first resistance threshold, the boosting the amplitude of the first frequency component and the amplitude of the second frequency component to a first preset value includes:
when the target insulation resistance value is higher than a first resistance threshold value, the amplitude of the first frequency component and the amplitude of the second frequency component are both increased to 30V;
when the target insulation resistance value is lower than a second resistance threshold value, reducing the amplitude of the first frequency component and the amplitude of the second frequency component to a second preset value, including:
and when the target insulation resistance value is higher than the first resistance threshold value, reducing the amplitude of the first frequency component and the amplitude of the second frequency component to 5V.
Optionally, the first resistance threshold is 500K ohms, and the second resistance threshold is 400K ohms.
Optionally, the first target multiple is 1;
reducing the frequency value of the first frequency component and the frequency value of the second frequency component by a first target multiple when the target distributed capacitance value is higher than a first capacitance threshold value, comprising:
when the target distributed capacitance value is higher than a first capacitance threshold value, reducing the first frequency component to 0.5Hz, and reducing the second frequency component to 1 Hz;
when the target distribution capacitance value is higher than the second capacitance threshold value, increasing the frequency value of the first frequency component and the frequency value of the second frequency component by a first target multiple includes:
and when the target distribution capacitance value is higher than a second capacitance threshold value, increasing the first frequency component to 1Hz, and increasing the second frequency component to 2 Hz.
Optionally, the determining the target insulation resistance value and the target distribution capacitance value includes:
and calculating by adopting a double-frequency injection method to obtain the target insulation resistance value and the target distribution capacitance value.
In a second aspect, an embodiment of the present application further provides an insulation monitoring device, which includes an injection source circuit, a dual-phase-locked circuit and a core processor, wherein an output end of the injection source circuit is connected to an input end of a system to be monitored, an input end of the dual-phase-locked circuit is connected to the injection source circuit, and an output end of the dual-phase-locked circuit is connected to the core processor.
Optionally, the injection source circuit includes a sampling resistor Rs and a current limiting resistor R0, a first end of the sampling resistor Rs is connected to a first end of the current limiting resistor R0, a second end of the current limiting resistor R0 is connected to the three-phase reactor, and the controlled generated dual-frequency synthetic injection source is injected into the three-phase reactor after passing through the sampling resistor Rs and the current limiting resistor R0.
In a third aspect, embodiments of the present application further provide an insulation monitoring system, which includes a processor, a memory, and a program or instructions stored on the memory and executable on the processor, and when executed by the processor, the program or instructions implement the steps of the method according to the first aspect.
In a fourth aspect, embodiments of the present application further provide a readable storage medium, on which a program or instructions are stored, which when executed by a processor implement the steps of the method according to the first aspect.
Has the advantages that:
the invention provides a double-frequency injection insulation monitoring method, which comprises the steps of firstly determining a target insulation resistance value and a target distribution capacitance value; when the target insulation resistance value is higher than the first resistance threshold value, the amplitude of the first frequency component and the amplitude of the second frequency component are increased to a first preset value; when the target insulation resistance value is lower than a second resistance threshold value, reducing the amplitude of the first frequency component and the amplitude of the second frequency component to a second preset value; the first resistance threshold is higher than the second resistance threshold; when the target distribution capacitance value is higher than the first capacitance threshold value, reducing the frequency value of the first frequency component and the frequency value of the second frequency component by a first target multiple; and when the target distribution capacitance value is higher than the second capacitance threshold value, increasing the frequency value of the first frequency component and the frequency value of the second frequency component by a first target multiple, wherein the first capacitance threshold value is larger than the second capacitance threshold value. Therefore, the insulation resistance and the distributed capacitance are solved according to the double-frequency injection method, then compared with the threshold value, the frequency and the amplitude of the first frequency component and the second frequency component in the injection source are modified, and then the insulation resistance value is calculated according to the double-frequency injection method again. The method solves the problems that the measurement error of the insulation resistance is larger due to the fact that the current of the injection source circuit is smaller when the insulation resistance is large and the measurement error is larger due to the fact that the resistance component of the current in the injection source circuit is smaller when the distributed capacitance is overlarge in the traditional injection type monitoring method, and can effectively improve the accuracy of insulation monitoring resistance measurement.
Drawings
FIG. 1 is a flow chart of a dual frequency injection insulation monitoring method in accordance with a preferred embodiment of the present invention;
FIG. 2 is a diagram illustrating an exemplary wiring diagram for a dual frequency injection insulation monitoring method according to a preferred embodiment of the present invention;
FIG. 3 is an equivalent circuit diagram of a single point insulation fault in accordance with a preferred embodiment of the present invention;
FIG. 4 is a circuit diagram of an injection source according to a preferred embodiment of the present invention;
FIG. 5 is a schematic diagram of a voltage-current detection method according to a preferred embodiment of the present invention;
FIG. 6 is a circuit diagram of a biphase phase lock circuit in accordance with a preferred embodiment of the present invention;
FIG. 7 is a schematic diagram of a filtering method according to a preferred embodiment of the present invention;
fig. 8 is a logic block diagram of the variable frequency transformer of the dual frequency injection insulation monitoring method according to the preferred embodiment of the present invention.
Detailed Description
The technical solutions of the present invention are described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, the present invention provides a dual-frequency injection insulation monitoring method, applied to an insulation monitoring device, including:
determining a target insulation resistance value and a target distribution capacitance value;
when the target insulation resistance value is higher than the first resistance threshold value, the amplitude of the first frequency component and the amplitude of the second frequency component are increased to a first preset value;
when the target insulation resistance value is lower than a second resistance threshold value, reducing the amplitude of the first frequency component and the amplitude of the second frequency component to a second preset value; the first resistance threshold is higher than the second resistance threshold;
when the target distribution capacitance value is higher than the first capacitance threshold value, reducing the frequency value of the first frequency component and the frequency value of the second frequency component by a first target multiple;
and when the target distribution capacitance value is higher than the second capacitance threshold value, increasing the frequency value of the first frequency component and the frequency value of the second frequency component by a first target multiple, wherein the first capacitance threshold value is larger than the second capacitance threshold value.
It should be noted that, in the above steps, the order of each of the adjustment steps for raising or lowering may be changed, or may be performed simultaneously. However, each step needs to be changed for a period of time, for example, 5 minutes before the change can be continued, so that the stability of the system can be improved. The first frequency component may refer to a frequency of the injected low-frequency signal, and the second frequency component may refer to a voltage amplitude of the injected low-frequency signal.
According to the double-frequency injection insulation monitoring method, the insulation resistance and the distributed capacitance are solved according to the double-frequency injection method, then the two insulation resistance and the distributed capacitance are compared with the threshold value, the frequency and the amplitude of two frequency components in the injection power supply are modified, and then the insulation resistance value is calculated according to the double-frequency injection method. The method solves the problems that the measurement error of the insulation resistance is larger due to the fact that the current of the injection source circuit is smaller when the insulation resistance is large and the measurement error is larger due to the fact that the resistance component of the current in the injection source circuit is smaller when the distributed capacitance is overlarge in the traditional injection type monitoring method, and can effectively improve the accuracy of insulation monitoring resistance measurement.
Optionally, determining the target insulation resistance value and the target distributed capacitance value comprises:
and calculating by adopting a double-frequency injection method to obtain a target insulation resistance value and a target distribution capacitance value. The specific steps can be as follows.
Referring to fig. 2, the dual-frequency injection insulation monitoring method may be applied to a variable frequency and variable voltage dual-frequency injection insulation monitoring device, which is connected to an IT (i.e., a neutral point and a load are not grounded) system through a three-phase reactor. Compared with the power frequency of 50HZ, under the condition that the insulation performance of the system is good, the current limiting resistors inside the three-phase reactor and the insulation monitoring device provide great impedance, so that the insulation performance of the IT system is good. Considering the IT system according to a linear system, the injected two different frequency components are mutually independent, and the total insulation resistance and the total distributed capacitance of the system can be calculated according to a dual-frequency injection method.
In fig. 2, when a single-point ground fault occurs in the branch f of the IT system, the equivalent circuit is as shown in fig. 3. For the fault branch, when the injection signal frequency is f1, the voltage to ground of the fault branch is
Leakage current of
At frequency f2, the voltage to ground of the faulty branch is
Leakage current of
Cf is the equivalent capacitance of branch f, RfFor equivalent insulation resistance of branch f to ground, the following equation can be listed:
in the formula, RfDenotes the insulation resistance of the branch f to ground, pi denotes a constant, C1Representing the capacitance to ground of branch f.
Thus, the magnitude of the insulation resistance to ground of the fault load branch is obtained:
in the formula, RfThe branch f is represented by the insulation resistance to ground, and k is the injection frequency ratio.
The resistance calculated according to equation 2 is the on-line monitoring insulation resistance of branch f. When the injection signal frequency is f1, the effective value of the earth voltage of the fault branch is Uf1Effective value of leakage current is If1(ii) a At the frequency of f2, the effective value of the earth voltage of the fault branch is Uf2Effective value of leakage current is If2。
When the other branches of the system shown in fig. 2 are well insulated, i.e. the insulation resistance is considered to be infinite, the insulation resistance of the faulty branch is the total insulation resistance of the system.
And because no voltage transformer is installed at the bus of the IT system, the Uf cannot be directly measured and needs to be obtained through a circuit shown in FIG. 4. The injection source circuit of the frequency conversion and transformation dual-frequency injection insulation monitoring method and device is shown in figure 4. The controlled generated double-frequency synthesis injection source is injected into the three-phase reactor after passing through a sampling resistor Rs and a current limiting resistor R0. Two paths of collected signals are led out from two ends of the sampling resistor Rs, wherein the voltage Ur close to the side of the current limiting resistor R0 is a voltage signal collected by a system. The voltage across the sampling resistor Rs is subjected to a differential amplifier circuit to obtain a current signal (actually, a converted voltage value) Uir. Then, the effective value Uf is found again.
In the formula, RsThe resistance of the sample is represented by the resistance,
indicating that the faulty branch is connected to ground,
represents a sampling resistance of twoThe terminal voltage signal of the voltage is detected,
representing a differential amplified voltage value.
Therefore, Ur and Uir may be determined.
Further, the voltage signal Ur and the current signal Uir are taken as signals to be measured, and then dual-frequency components are respectively identified from the signals to be measured. Referring to fig. 5, after the voltage signal and the current signal pass through the biphase phase-locked circuit, the output signals are connected to the core processor. The principle of the biphase phase-locked circuit is shown in fig. 6, which uses the dual-frequency signals as reference signals. The reference signal and the signal of the reference signal after shifting the phase by 90 degrees are multiplied with the signal to be measured respectively, then pass through a low-pass filter 1 and a low-pass filter 1 respectively, and are output after mean value filtering. Taking the voltage signal Ur as an example, the specific principle is as follows:
the signal to be measured Ur contains components with frequencies f1, f2 (two low-frequency signals) and power frequency f3 respectively. Ur may be represented as follows:
Ur＝Uf1sin(2πf1t+α)+Uf2sin(2πf2t+β)+Uf3sin(2πf3t+γ) (4)
in the formula, Uf1, Uf2, and Uf3 respectively represent the amplitudes of the injection frequency f1, f2, and power frequency f3 components; α, β, γ represent the phases of the injection frequency f1, f2, and power frequency f3 components, respectively. In order to calculate the resistance and capacitance by the dual-frequency injection method, it is necessary to obtain the values of Uf1 and Uf 2. The following describes the principle of the biphase phase-locked circuit by taking the value of Uf1 as an example.
Introducing a reference signal A with the frequency of f1, shifting the phase by 90 degrees to become a signal B, and then obtaining
In the formula, t represents a time constant.
A. Multiplying the B signal by the signal Ur to be measured respectively to obtain the following results:
in the formula, only cos alpha is a constant, the others are sinusoidal, and the rest is the constant as long as a low-pass filter is arranged to filter out the other components
Corresponding to output 1 in fig. 5. Similarly, B is multiplied by Ur and is obtained by low-pass filtering
Corresponding to the output 2 in fig. 5, this is only an example and is not limited.
To further filter out the sinusoidal components in the above expression, the software portion of the core processor continues with low pass filtering and, after filtering, with mean filtering, as shown in fig. 7. After the sinusoidal components are sufficiently filtered, the root mean square value is obtained, and then Uf1 is obtained. Namely:
similarly, Uf2, Uir1, Uir2 can be obtained. Then, the target insulation resistance value and the target distribution capacitance value can be obtained by substituting the formula (3) and the formula (2).
Further, the obtained target insulation resistance value and the target distribution capacitance value are compared with preset high and low thresholds of insulation resistance and high and low thresholds of distribution capacitance, so as to change the frequency and amplitude of two frequency components of the injection source loop, as shown in fig. 8.
Optionally, when the target insulation resistance value is higher than the first resistance threshold, the boosting the amplitude of the first frequency component and the amplitude of the second frequency component to a first preset value includes:
when the target insulation resistance value is higher than the first resistance threshold value, the amplitude of the first frequency component and the amplitude of the second frequency component are both increased to 30V; when the target insulation resistance value is lower than the second resistance threshold value, reducing the amplitude of the first frequency component and the amplitude of the second frequency component to a second preset value, including: when the target insulation resistance value is higher than the first resistance threshold value, both the amplitude of the first frequency component and the amplitude of the second frequency component are reduced to 5V.
Optionally, the first resistance threshold is 500K ohms and the second resistance threshold is 400K ohms.
Optionally, the first target multiple is 1;
reducing the frequency value of the first frequency component and the frequency value of the second frequency component by a first target multiple when the target distributed capacitance value is higher than the first capacitance threshold value, comprising: when the target distribution capacitance value is higher than the first capacitance threshold value, reducing the first frequency component to 0.5Hz, and reducing the second frequency component to 1 Hz; increasing the frequency value of the first frequency component and the frequency value of the second frequency component by a first target multiple when the target distributed capacitance value is higher than the second capacitance threshold value, including: when the target distribution capacitance value is above the second capacitance threshold, the first frequency component is increased to 1Hz and the second frequency component is increased to 2 Hz.
In this optional embodiment, when the obtained insulation resistance value is greater than the set insulation resistance high threshold, the amplitudes of both frequency components are raised to 30V, and then the amplitude is injected into the system, so that the insulation resistance is solved, and the precision is improved. When the calculated insulation resistance value is smaller than the set insulation resistance low threshold value (400K ohm is recommended), the amplitude of the two frequency components is reduced to 5V, and then the two frequency components are injected into the system, so that the insulation resistance is solved. When the calculated distributed capacitance value is larger than the set distributed capacitance high threshold value, the frequency values of the two frequency components are reduced by 1 time, namely 0.5Hz and 1Hz, and then the frequency values are injected into the system, so that the insulation resistance is solved, and the precision is improved. When the calculated distributed capacitance value is smaller than the set distributed capacitance low threshold value, the frequency values of the two frequency components are increased by 1 time, namely 1Hz and 2Hz, and then the frequency values are injected into the system, so that the insulation resistance is solved, and the precision is improved. After the two frequency components are synthesized, the power is amplified, and then the two frequency components are injected into the IT system through the injection source loop shown in FIG. 4.
The double-frequency injection insulation monitoring method solves the problems that the measurement error of the insulation resistance is larger due to the fact that the current of an injection source circuit is smaller when the insulation resistance is large and the measurement error is larger due to the fact that the resistance component of the current in an injection source circuit is smaller when the distributed capacitance is overlarge in the traditional injection type monitoring method, effectively improves the accuracy of insulation monitoring resistance measurement, and greatly improves the safety of a nuclear reactor voltage stabilizer system.
The embodiment of the application further provides an insulation monitoring device, including injecting source circuit, biphase phase-locked circuit and core processor, the output of injecting source circuit is connected with the input of treating the monitoring system, biphase phase-locked circuit's input with it connects to inject source circuit, just biphase phase-locked circuit's output is connected with the treater.
In this embodiment, the entire monitoring device may include a power board, a core processor board (core processor), an injection source board (injection source circuit). The incoming line of the power panel comes from a control power AC220V, is converted into positive and negative DC12V, and is sent to the core panel and the injection source panel; the injection source board is responsible for generating a low-frequency signal and injecting the low-frequency signal into the IT system; the core processor is responsible for collecting voltage and current of the injection source loop, receiving current signals of the collecting plate through communication, and calculating the total insulation resistance of the IT system and the insulation resistance values of all branches. Here, the examples are only given, and are not limiting.
Optionally, the injection source circuit includes a sampling resistor Rs and a current limiting resistor R0, a first end of the sampling resistor Rs is connected to a first end of the current limiting resistor R0, a second end of the current limiting resistor R0 is connected to the three-phase reactor, and the controlled generated dual-frequency synthetic injection source is injected into the three-phase reactor after passing through the sampling resistor Rs and the current limiting resistor R0.
The insulation monitoring device can realize each embodiment of the monitoring method and achieve the same beneficial effects, and the detailed description is omitted here.
Embodiments of the present application also provide an insulation monitoring system, which includes a processor, a memory, and a program or instructions stored on the memory and executable on the processor, and when executed by the processor, the program or instructions implement the steps of the method described above.
The insulation monitoring system can realize each embodiment of the monitoring method and achieve the same beneficial effects, and the detailed description is omitted here.
Optionally, an embodiment of the present application further provides a readable storage medium, on which a program or instructions are stored, and when executed by a processor, the program or instructions implement the steps of the method described above. And can achieve the same beneficial effects, and the details are not repeated here.
The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.
Claims (9)
1. A dual-frequency injection insulation monitoring method is applied to an insulation monitoring device and is characterized by comprising the following steps:
determining a target insulation resistance value and a target distribution capacitance value;
when the target insulation resistance value is higher than a first resistance threshold value, the amplitude of the first frequency component and the amplitude of the second frequency component are increased to a first preset value;
when the target insulation resistance value is lower than a second resistance threshold value, reducing the amplitude of the first frequency component and the amplitude of the second frequency component to a second preset value; the first resistance threshold is higher than the second resistance threshold;
when the target distribution capacitance value is higher than a first capacitance threshold value, reducing the frequency value of the first frequency component and the frequency value of the second frequency component by a first target multiple;
and when the target distribution capacitance value is higher than a second capacitance threshold value, increasing the frequency value of the first frequency component and the frequency value of the second frequency component by a first target multiple, wherein the first capacitance threshold value is larger than the second capacitance threshold value.
2. The method of claim 1, wherein boosting the amplitude of the first frequency component and the amplitude of the second frequency component to a first preset value when the target insulation resistance value is higher than a first resistance threshold value comprises:
when the target insulation resistance value is higher than a first resistance threshold value, the amplitude of the first frequency component and the amplitude of the second frequency component are both increased to 30V;
when the target insulation resistance value is lower than a second resistance threshold value, reducing the amplitude of the first frequency component and the amplitude of the second frequency component to a second preset value, including:
and when the target insulation resistance value is higher than the first resistance threshold value, reducing the amplitude of the first frequency component and the amplitude of the second frequency component to 5V.
3. The method of claim 2, wherein the first resistance threshold is 500K ohms and the second resistance threshold is 400K ohms.
4. The method of claim 1, wherein the first target multiple is 1;
reducing the frequency value of the first frequency component and the frequency value of the second frequency component by a first target multiple when the target distributed capacitance value is higher than a first capacitance threshold value, comprising:
when the target distributed capacitance value is higher than a first capacitance threshold value, reducing the first frequency component to 0.5Hz, and reducing the second frequency component to 1 Hz;
when the target distribution capacitance value is higher than the second capacitance threshold value, increasing the frequency value of the first frequency component and the frequency value of the second frequency component by a first target multiple includes:
and when the target distribution capacitance value is higher than a second capacitance threshold value, increasing the first frequency component to 1Hz, and increasing the second frequency component to 2 Hz.
5. The method of claim 1, wherein determining the target insulation resistance value and the target distributed capacitance value comprises:
and calculating by adopting a double-frequency injection method to obtain the target insulation resistance value and the target distribution capacitance value.
6. The insulation monitoring device is characterized by comprising an injection source circuit, a two-phase-locked circuit and a core processor, wherein the output end of the injection source circuit is connected with the input end of a system to be monitored, the input end of the two-phase-locked circuit is connected with the injection source circuit, and the output end of the two-phase-locked circuit is connected with the core processor.
7. The device of claim 6, wherein the injection source circuit comprises a sampling resistor Rs and a current limiting resistor R0, a first end of the sampling resistor Rs is connected with a first end of the current limiting resistor R0, a second end of the current limiting resistor R0 is connected with a three-phase reactor, and the controlled generated dual-frequency synthesis injection source is injected into the three-phase reactor after passing through the sampling resistor Rs and the current limiting resistor R0.
8. An insulation monitoring system comprising a processor, a memory and a program or instructions stored on the memory and executable on the processor, the program or instructions when executed by the processor implementing the steps of the method according to any one of claims 1 to 5.
9. A readable storage medium, characterized in that it stores thereon a program or instructions which, when executed by a processor, implement the steps of the method according to any one of claims 1-5.
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