KR20180113402A - Intelligent power facility failure prediction system and method using three-phase leakage current measurement method by insulation deterioration - Google Patents

Abstract

The present invention relates to an intelligent power facility failure prediction system using a three-phase leakage current measurement method by insulation deterioration and a method thereof to detect and analyze the state of the change of a leakage current over a long period of time in real time and prevent power facility accidents. The intelligent power facility failure prediction system includes a leakage current detector for measuring resistive leakage current in three phase power facilities, an analyzer for analyzing data detected by the leakage current detector and predicting the progress of insulation deterioration in the three-phase power facilities, and a manager for communicating with the analyzer and comprehensively managing phase information in a three phase power facilities. It is possible to reduce installation time and construction costs by directly attaching a detection device to a ground wire.

Description

TECHNICAL FIELD The present invention relates to an intelligent power facility failure prediction system and method using three-phase leakage current measurement method using insulation deterioration,

The present invention relates to a system and method for intelligent power equipment failure diagnosis using a three-phase leakage current measurement method using insulation deterioration, and more particularly, The present invention relates to an intelligent power equipment failure prediction system and method using a three-phase leakage current measurement method using insulation deterioration.

In general, power generated from hydro, thermal or nuclear power plants is boosted to the high pressure required for long-distance transmission and sent to the substation. At this time, the electric power having the phase determined by the generator, that is, the electric power having the phase difference (difference of Sin 120 ° of each phase) of P1, P2, P3 (absolute phase) is divided into phases (P1, P2, P3) The transmitted power is decompressed to the voltage required for power distribution, and the power is distributed to each phase separated from the generator.

This electricity is clean energy that is easy to use and manage and it is an essential energy source in modern society. However, electricity is a major source of fire in urban areas, and the cause of such electric fires is leakage current.

The use of electricity is convenient, but it also has the greatest risk of being misused for proper management or use. Electric fires, electric shocks, power outages, and other serious accidents are also possible. Generally, if the insulation of the electric wire coating or the electric device is aged or damaged and the insulator is damaged, the leakage current flows from the electric wire to the ground through the portion. There is a danger of an electric shock accident when the human body touches the place where the leakage current flows out. In the place where the excessive leakage current flows, overheating by the arc occurs and the ignition is caused by the flammable material in the vicinity.

In addition, a breaker for detecting leakage current and interrupting the current according to the leakage current has been installed in electric devices and electric equipment for a long time. In the general circuit of electrical equipment, it is stipulated to protect general wiring circuit through leakage circuit breaker when leakage current is 30mA or more, and to protect power wiring circuit through leakage circuit breaker when leakage current is more than 50mA in power circuit.

The leakage current flows through the wiring circuit as a sum of the resistive leakage current Igr and the capacitive leakage current Igc as a sum of electrical vectors. In reality, the leakage current leading to the fire is the resistive leakage current Igr. In general, the shut-off circuits cut off electricity only by the leakage current, so that it is not possible to manage the electric interrupting by the accurate leakage current judgment.

The capacitive leakage current (Igc) is inevitably generated in a fluorescent lamp, a computer, a refrigerator, and a washing machine. For this reason, the circuit breaker frequently switches off Thus, the user may lose his or her life and property when a fire is actually generated while the electric leakage breaker is removed or bypassed.

In addition, there are many kinds of facilities such as electric pole, electric wire, transformer, lightning arrester to supply electric power to the customers, and switchgears for preventing electric accidents and minimizing the fault area and repairing the faults.

Most of these equipments are exposed to nature and they are subject to external environmental effects. As time goes on, natural characteristics deteriorate and insulation characteristics change due to physical effects such as lightning or commercial frequency overvoltage. If left untreated, it will spread to a major accident such as a short. Therefore, the power supplier is periodically diagnosing and repairing the equipment abnormality. Especially, when a large number of lighting apparatuses are arranged in a multi-use facility and a complex office space, it is difficult to predict leakage current and to predict leakage current such as occurrence location.

However, most of the equipments and methods used for the diagnosis of facilities are the method of extracting the overheat points by using ultrasonic wave (partial discharge detection) or thermal imaging equipment. This is an unscientific method in that the criterion to analyze is ambiguous, that is, it is a result of single measurement rather than continuity, and there is a difference in accuracy due to the analytical ability of the individual.

In addition, the price of ultrasonic or thermal imaging equipment is more than tens of millions of won, and the measurement work is influenced by the weather and the environment, so it can not be said to be an effective measurement method against the diagnosis time and cost.

In addition to the above method, there is a method of detecting the magnitude of the leakage current flowing through the ground wire connected to the equipment to check whether or not an accident can occur. However, this method also analyzes the instant leakage current at the time of measurement, In addition, when determining the deterioration characteristics in the lightning arrester, etc., the leakage current (resistive current) of the effective component as well as the component such as the third harmonic act as a factor for determining the deterioration of the main component. In order to measure these items, And the time (risk) and cost for the measurement work are in question.

One example of the technique for solving such a problem is described in Documents 1 and 2 below.

For example, the following Patent Document 1 discloses a method comprising the steps of: (a) removing harmonics and noise of a voltage that is reduced through a voltage transformer PT by receiving a voltage; (b) (C) measuring the current difference by installing it on the outside of the power supply line and the neutral line using a ZCT transformer, (d) receiving the output of the leakage current measuring unit, (E) calculating a phase angle by using the detected voltage phase and current phase, calculating a resistive leakage current Igr by a phase angle with respect to the image current Io, And a capacitive leakage current (Igc), and (f) transmitting the output of the step (e) to an external terminal.

Patent Document 2 discloses a pulse generator using a pulse wave filter that uses a resistive leakage current waveform and a phase leakage characteristic of a capacitive leakage current waveform. The pulse generator includes a pulse generator for generating a pulse waveform through a voltage waveform input from an electric cable, A semiconductor switch which is triggered by a detection signal generated while a leak current flows in a video current transformer and is activated, and a pulse waveform generated by the pulse generator while being triggered by the semiconductor switch, wherein a current amplitude of the pulse waveform and a leakage And a leakage current detector for detecting a leakage current while calculating a magnitude of the leakage current by comparing the current magnitudes of the current waveforms.

In addition, as shown in FIG. 1, the following Patent Document 3 discloses a video signal processing apparatus including a video current sensing means 1 for detecting a leakage current video signal, a signal amplifying portion 2 for amplifying a signal obtained from the video current sensing means, A wave filter means (3) for removing a noise component contained in an output signal of the amplifying section, a phase voltage detecting section (4) for detecting a phase voltage signal, A phase difference discrimination section 6, PLL sections 7 and 8 for obtaining a sinusoidal wave, ADCs 9, 10, 11, 12 and 13 and a CPU 14, The leakage current effective component (Igr) is calculated by integrating the voltage signal and the leakage current image signal for a predetermined period by integrating the four calculation terms obtained by multiplying the cosine wave (cosωt) and sine wave (sinωt) Or a microphone for calculating a phase difference angle Leakage current to an active ingredient and a controller circuit (MCU), the display unit 16 is described for the measurement calculation circuit.

Korean Registered Patent No. 10-1358050 (Registered on April 21, 2014) Korean Patent Laid-Open Publication No. 2016-0147599 (published Dec. 23, 2016) Korean Registered Patent No. 10-1075484 (registered on October 14, 2011)

However, in the technique disclosed in the above-described Patent Document 1, the leakage current can be analyzed so that the measured effective leakage current can be externally confirmed through wireless communication. However, in the three-phase power equipment, B, and C phases in which the leakage occurs.

In the technique disclosed in Patent Document 2, the magnitude of the resistive leakage current Igr and the capacitive leakage current Igc are judged to detect the leakage current, and the magnitude of the resistive leakage current Igr flowing through the wire is detected as it is, However, since the magnitude of the capacitive leakage current (Igc) is determined to be a leakage current only when the leakage current setting value is about three times as large as the reference value, analysis based on the instantaneous leakage current at the time of measurement lacks accuracy .

In the technique disclosed in Patent Document 3, the magnitude and the phase difference of the effective component Igr of the leakage current are displayed on the external display device and are displayed to the user, so that the grounded image can be found and the measurement point of the measured electric line is changed The grounded phase and the grounding point are checked through the measured data. However, the technique disclosed in Patent Document 3 also has a problem in that it is impossible to grasp in which of the phases A, B, and C the leakage current is leaked in the power equipment.

An object of the present invention is to solve the above-mentioned problems, and it is an object of the present invention to provide a three-phase power facility device capable of detecting and analyzing a change in leakage current over a long period of time in real time, The present invention provides an intelligent power equipment failure prediction system and method using a three-phase leakage current measurement method by insulation deterioration that can accurately detect leakage.

Another object of the present invention is to provide a method and apparatus for detecting leakage current flowing through a common ground line connected to each equipment in a place where a plurality of facilities (switches, arresters, insulators, etc.) And to provide an intelligent power equipment failure prediction system and method using a three-phase leakage current measurement method.

It is still another object of the present invention to provide an intelligent power equipment failure prediction method using a three-phase leakage current measurement method by insulation deterioration capable of predicting various information in a power equipment having three phases by detecting and analyzing a change state of leakage current over a long period of time System and method.

It is still another object of the present invention to provide an intelligent power system using a three-phase leakage current measurement method using insulation deterioration capable of accurately detecting a leakage position in a power equipment having three phases by detecting and analyzing a change state of leakage current over a long period of time. And to provide a fault prediction system and method.

In order to achieve the above object, an intelligent power equipment failure prediction system according to the present invention is an intelligent power equipment failure prediction system capable of preventing a power facility accident due to insulation deterioration by detecting and analyzing a change state of a leakage current, An analyzer for analyzing the data detected by the leakage current detector and for predicting the progress of the insulation deterioration in the three phase power plant, an analyzer for communicating with the analyzer, And a management unit that manages the integrated management system.

Further, in the intelligent power equipment failure prediction system according to the present invention, the leakage current detector detects only leakage currents in each phase in synchronization with a leakage current having the same phase as the voltage detected at one phase of the three phases in the three-phase power plant.

Further, in the intelligent power equipment failure prediction system according to the present invention, the analyzer may include a communication unit for wireless communication with the leakage current detector and the manager, averaging leakage current accumulated for a predetermined time with respect to the resistive leakage current detected by the leakage current detector A control unit for predicting the progress of the insulation deterioration according to a predetermined failure prediction reference based on an average value, and a display unit for displaying the progress of the insulation deterioration in each of the distribution lines on the A, B, and C basis.

Further, in the intelligent power equipment failure prediction system according to the present invention, the leakage current detector transmits detection information detected on an angle of three phases in a three-phase power plant to the analyzer in a wireless communication manner.

In the intelligent power equipment failure prediction system according to the present invention, the analyzer and the manager communicate with each other by PLC or WIFI method.

Further, in the intelligent power equipment failure prediction system according to the present invention, the leakage current detector includes a current detector (including insulation and spiral) phase detector of the secondary side A, B, C of the current transformer installed in the three phase power facility and the three phase power facility And the leakage current is detected in which of the phases A, B, and C is leaked.

In order to achieve the above object, an intelligent power equipment failure prediction method according to the present invention is a power equipment failure prediction method capable of preventing a power facility accident due to insulation deterioration by detecting and analyzing a change state of three- a) detecting a leakage current using a common ground line in a three-phase power plant at a leakage current detector, b) predicting the progress of insulation deterioration per hour in the analyzer according to the leakage current sensed in the step a) (c) managing in which of the A, B, and C phases of the three-phase power plant the insulation deterioration will occur in the manager according to the prediction in the step (b).

In the intelligent power equipment failure prediction method according to the present invention, the step (b) averages the leakage current accumulated for a predetermined time and predicts the progress of the insulation deterioration according to a predetermined failure prediction reference based on the average value .

In the intelligent power equipment failure prediction method according to the present invention, the step (a) includes a line transformer (including insulation and spiral) phase detector provided on a secondary side A, B, C of a current transformer installed in a three- And the leakage current flowing in the common ground line in the three-phase power plant is detected to detect which of the phases A, B and C is leaked.

Further, in the intelligent power equipment failure prediction method according to the present invention, the predicted insolation deterioration progress information in the step (b) is transmitted to the manager by the PLC or WIFI method.

As described above, according to the intelligent power equipment failure prediction system and method using the three-phase leakage current measurement method by insulation deterioration according to the present invention, in a place where a plurality of equipments (switches, lightning arresters, It is more economical than the method of attaching the detecting device to each individual facility by detecting the leakage current flowing through the connected common grounding line and it is possible to reduce installation time and construction cost by directly attaching the detecting device to the grounding line.

According to the intelligent power equipment failure prediction system and method using the three-phase leakage current measurement method using the insulation deterioration according to the present invention, the data detected by the leakage current detector in the analyzer is analyzed, A configuration for predicting the progress is provided, and the effect of the power facility accident can be prevented in advance by detecting and analyzing the state of change of the leakage current over a long period of time in real time instead of the one-time measurement.

According to the intelligent power equipment failure prediction system and method using the three-phase leakage current measurement method using the insulation deterioration according to the present invention, one of the secondary side A, B, and C of the current transformer and the three- (Including insulation and spiral) phase detectors provided above, it is possible to accurately detect whether the leakage current is leaked in the phase A, B, or C phase.

1 is a block circuit diagram of a conventional measuring and calculating device for measuring leakage current effective components,
2 is a block diagram of an intelligent power equipment failure prediction system using a three-phase leakage current measurement method by insulation deterioration according to the present invention.
FIG. 3 is a view for explaining a process of measuring a three-phase leakage current by the leakage current detector shown in FIG. 2;
4 is a block diagram showing the configuration of the analyzer shown in FIG. 2;
5 is a process diagram for explaining an intelligent power equipment failure prediction process using a three-phase leakage current measurement method by insulation deterioration according to the present invention.

These and other objects and novel features of the present invention will become more apparent from the description of the present specification and the accompanying drawings.

First, the basic concept of the present invention will be described.

In the intelligent power equipment failure prediction system and method using the three-phase leakage current measurement method by insulation deterioration according to the present invention, a plurality of equipments (switches, lightning arresters, insulators, etc.) are assembled and installed And detects a leakage current flowing in a common ground line connected to each equipment at a place.

Also, in order to prevent accidents such as transformer burnout and explosion due to overload in the electric power supply transformer (P.Tr) for supplying electric power to the customer, the overload current is detected in the P.Tr secondary cut-off line and the alarm signal is transmitted do.

That is, in the present invention, all electric power facilities considers the insulation ability of the support and the facility as the top priority for stable power transportation, and when the insulation deterioration occurs in such electric power facilities, the magnitude and the state of leakage current flowing through the ground wire are accurately detected and analyzed To prevent accidents. In order to achieve the best diagnostic criteria, it is necessary to detect and analyze the state of change of the leakage current over a long period of time in real-time, not in a one-time measurement.

More specifically, the present invention relates to a method of monitoring the deterioration state of an electric power facility and a power distribution facility in an intelligent manner, (Igr) flowing to the ground of the three-phase conductor line by using the resistive leakage current (hereinafter referred to as "leakage current") which causes the insulation breakdown among the currents combined with the noise, The system is designed to predict the progress of insulation deterioration according to the increase rate of leakage current per hour and to prevent accidents in advance.

The term " three-phase power plant " as used in the present invention includes a conventional three-phase transformer or high voltage plant having phases A, B and C and primary and secondary power cables (cables) connected to the three- do.

Hereinafter, the configuration of the present invention will be described with reference to the drawings.

2 is a block diagram of an intelligent power equipment failure prediction system using a three-phase leakage current measurement method by insulation deterioration according to the present invention.

As shown in FIG. 2, the intelligent power equipment failure prediction system according to the present invention is an intelligent power equipment failure prediction system capable of preventing a power facility accident due to insulation deterioration by detecting and analyzing a change state of a leakage current, An analyzer (300) for analyzing data detected by the leakage current detector (100) and predicting the progress of the insulation deterioration in the three-phase power plant, and a controller And a manager 500 capable of communicating with the controller 300 and totally managing the phase information in the three-phase power plant.

The configuration and operation of the leakage current detector 100 will be described with reference to FIG.

FIG. 3 is a view for explaining a process of measuring a three-phase leakage current by the leakage current detector shown in FIG. 2. FIG.

3, the leakage current detector 100 is described as a three-phase transformer connected to A, B, and C, or a structure connected to a high voltage facility, a secondary line of a three-phase transformer and a neutral line that can be used as a ground line. However, The present invention can be applied to a technique in which a conventional three-phase power plant is applied.

The leakage current detector 100 according to the present invention detects leakage currents of each phase by synchronizing with the leakage current having the same phase as the voltage detected on one phase of three phases in the three-phase power plant, and determines which one of the phases A, B, .

As shown in Fig. 3, a leakage current is detected from a current transformer installed in a wiring 200a which is one of the ground lines of the three-phase transformer or a wiring 200b which is one of the ground lines of the high- B, and C phases of the three-phase transformer can be determined by comparing phases recognized by one or more line phase detectors held on the secondary side of the three-phase transformer. The leakage currents from the current transformers provided in the wiring 200a or the wiring 200b, It is possible to judge whether or not it is leaked on the screen. Such image information detection is described in detail in Patent Registration No. 10-0594778 or 10-0730627 filed and filed by the applicant of the present application, and can be easily realized by utilizing it. Such phase detection will be briefly described as follows.

The leakage current detector 100 generates a pulse at a phase angle of 90 ° with respect to a waveform of an arbitrary phase (for example, A-phase) recognized by the three-phase transformer, (A, B, and C-phase waveforms) of waveforms A, B, and C that are input from a line (including insulation and spiral) Phase waveform of the three-phase transformer, and the leakage current detector 100 can grasp the phases of the three-phase transformer and phase of the distribution line.

Also, the leakage current detector 100 detects leakage currents in the respective distribution lines using the A, B, and C phases of the distribution line as described above and the neutral line (N). For example, 380 V is applied between the phases A and B, between the phases B and C and between the phases C and A in the structure of a three-phase four-wire system. Between the phases A and N, between the phases B and N, and C And 220 V is applied between the phases A and B, the current between the phases A and N, between the phases B and N, and between the phases C and N is detected, and the currents A, B, C on each of the distribution lines.

The information on the variation of the current value detected in each of the distribution lines on the A, B, and C phases detected by the leakage current detector 100 is transmitted to the analyzer 300 through the wireless communication method. The analyzer 300 may be provided in the form of a portable module.

4 is a block diagram showing the configuration of the analyzer 300 shown in FIG.

As shown in FIG. 4, the analyzer 300 averages the leakage current accumulated for a predetermined time with respect to the resistive leakage current detected by the leakage current detector 100, and calculates a leakage current according to a predetermined failure prediction criterion based on the average value A control unit 310 for predicting the progress of the insulation deterioration, a communication unit 320 for wireless communication with the leakage current detector 100 and the manager 500, And a display unit 330 for displaying a status.

The control unit 310 includes a microprocessor as a computing member and a memory serving as a storage member. The memory 310 stores information on the occurrence criterion (failure prediction reference) of a power plant accident due to insulation deterioration in a three-phase power plant, The leakage detection values in the respective distribution lines on the A, B, and C phases measured at predetermined time intervals, for example, in minutes, are stored in the leakage current detector 100, and the microprocessor stores the leakage detection values stored in the memory The leakage current accumulated at predetermined time intervals is averaged, and the progress of the insulation deterioration is predicted according to a predetermined failure prediction reference based on the average value. In the above description, the control unit is realized by the memory and the microprocessor. However, the present invention is not limited to this and can be realized by a preset program.

The leakage current detector 100 and the communication unit 320 are connected to the communication unit 320 in a wireless communication manner and the communication unit 320 and the management unit 500 are connected in a PLC or WIFI manner by a transceiver having a normal transmission / And executes communication.

The display unit 330 is provided by a display member such as a normal LCD panel and displays the position of each of the power distribution lines A, B, and C on the display unit, the respective insulation deterioration of each of the power distribution lines A, B, Can be displayed. That is, the progress of the insulation deterioration realized by the control unit 310 can be expressed in the form of a number or a figure so that the user can visually recognize the deterioration.

As described above, the analyzer 300 measures the continuous leakage current, accumulates data, and determines the degree of change in the magnitude of the changed leakage current. In the leaked state (when the leakage current flows finely in the actual water distribution facility It is judged that there is an abnormality when the leakage current flows to some extent or more, which is not a serious state because leakage current is present in most cases).

The manager 500 is an administrator system that is provided in the manager's location (for example, the central control center), and is configured to perform the analysis according to the analysis result and the failure prediction criterion in the analyzer 300 transmitted by the PLC or WIFI method. It is provided to instruct the user to replace each distribution line on A, B, and C, and so on. In addition, the manager 500 may be provided with a notification means such as an alarm, for example, to automatically notify the administrator of the replacement of the distribution line according to the analysis result in the analyzer 300 and the failure prediction criterion.

As described above, in the intelligent power equipment failure prediction system using the three-phase leakage current measuring method according to the present invention, the analyzer 300 analyzes the data detected by the leakage current detector 100, It is possible to prevent a power plant accident in advance by detecting and analyzing the state of change of the leakage current over a long period of time in real time instead of a one-time measurement by providing a configuration for predicting the progress.

Next, an intelligent power equipment failure prediction method using the three-phase leakage current measuring method according to the present invention will be described with reference to FIG.

FIG. 5 is a process diagram for explaining an intelligent power equipment failure prediction process using a three-phase leakage current measurement method by insulation deterioration according to the present invention.

The intelligent power equipment failure prediction method according to the present invention is a power facility failure prediction method capable of preventing a power facility accident due to insulation deterioration by detecting and analyzing a change state of three-phase leakage current. In the leakage current detector, The leakage current is detected (S100).

For this purpose, a common ground line connected to each equipment is provided in a place where a plurality of equipments (switches, arresters, insulators, etc.) are installed, and a transformer is installed in a three-phase transformer or a high- Install a deflector. Accordingly, the leakage current detector 100 detects leakage currents in the respective distribution lines using the A, B, and C phases of the distribution line and the neutral line (N). Such detection is carried out over a long period of time in real time.

The analyzer 300 estimates the progress of the insulation deterioration per hour according to the leakage current sensed in the step S100 (S110).

That is, in the step S100, the leakage current accumulated for a predetermined time is averaged with respect to the resistive leakage current measurement value detected by the leakage current detector 100 and transmitted through the communication unit 320, And predicts the progress of the insulation deterioration according to the set failure prediction standard.

According to the prediction in the step S110, the manager 500 calculates the insulation deterioration in any of A, B, and C phases of the three-phase power equipment according to the analysis result and the failure prediction standard transmitted by the PLC or WIFI method in the analyzer 300 And instructs the user to replace each distribution line on A, B, and C (S120).

Although the present invention has been described in detail with reference to the above embodiments, it is needless to say that the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention.

By using the intelligent power equipment failure prediction system and method using the three-phase leakage current measurement method by insulation deterioration according to the present invention, installation time and construction cost can be reduced by directly attaching the detection device to the ground wire.

100: Leakage current detector
300: Analyzer
500: Manager

Claims (10)

An intelligent power equipment failure prediction system capable of preventing a power plant accident due to insulation deterioration by detecting and analyzing a change state of a leakage current,
A leakage current detector for measuring resistive leakage current in a three phase power plant,
An analyzer for analyzing the data detected by the leakage current detector and predicting the progress of the insulation deterioration in the three-phase power plant,
And a manager capable of communicating with the analyzer and managing the image information in the three-phase electric power facility in a comprehensive manner.
The method of claim 1,
Wherein said leakage current detector detects only leakage currents of each phase on a ground line by synchronizing a leakage current having the same phase as a voltage detected on one phase of three phases in a three phase power plant.
The method of claim 1,
The analyzer includes a communication unit for wireless communication with the leakage current detector and the manager, averaging leakage current accumulated for a predetermined time with respect to the resistive leakage current detected by the leakage current detector, And a display unit for displaying the progress of the insulation deterioration in each of the distribution lines on the lines A, B, and C. The intelligent power equipment failure prediction system according to claim 1,
The method of claim 1,
Wherein the leakage current detector transmits detection information detected on each of the three phases of the three-phase power plant to the analyzer in a wireless communication manner.
The method of claim 1,
Wherein the analyzer and the manager communicate in a PLC or WIFI manner.
The method of claim 1,
The leakage current detector detects a leak current leaked in any of the A, B, and C phases by a current transformer provided in a three phase power plant and a line phase detector provided on a secondary side A, B, C of a three phase power plant Wherein the intelligent power equipment failure prediction system comprises:
There is provided a power equipment failure prediction method capable of preventing a power plant accident due to insulation deterioration by detecting and analyzing a change state of three-phase leakage current,
(a) detecting a leakage current in a three-phase power plant using a common ground line in a leakage current detector,
(b) predicting the progress of the insulation deterioration per hour in the analyzer according to the leakage current sensed in the step (a)
(c) managing, in accordance with the prediction in the step (b), whether the insulation deterioration occurs in any one of phases A, B, and C of the three-phase power plant in the management device. .
8. The method of claim 7,
Wherein the step (b) averages the accumulated leakage current for a predetermined time and predicts the progress of the insulation deterioration according to a predetermined failure prediction reference based on the average value.
8. The method of claim 7,
In the step (a), the leakage current is detected by a line phase detector provided on the secondary side A, B, C of the current transformer installed in the three-phase power plant and the three-phase power plant, and the leakage current flowing in the common ground line And detecting whether any one of the phases A, B, and C is leaked.
9. The method of claim 8,
Wherein the predicted insolation deterioration progress information in the step (b) is transmitted to the manager by a PLC or WIFI method.

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