KR-20260063622-A - INSULATION MONITORING DEVICE TO REDUCE MEASUREMENT ERROR OF INSULATION RESISTANCE

KR20260063622AKR 20260063622 AKR20260063622 AKR 20260063622AKR-20260063622-A

Abstract

An insulation monitoring device according to one disclosed embodiment is an insulation monitoring device for monitoring the insulation status of one or more power lines, comprising: a signal generator that generates a test signal applied to the one or more power lines; a signal detector that measures a detection signal returning after the test signal passes through the one or more power lines; and a signal processor that calculates a composite insulation resistance representing the overall insulation status of the one or more power lines based on the test signal, the detection signal, and one or more internal resistances constituting the insulation monitoring device.

Inventors

홍종필

Assignees

충북대학교 산학협력단

Dates

Publication Date: 20260507
Application Date: 20241030

Claims (15)

In an insulation monitoring device for monitoring the insulation status of one or more power lines, A signal generator that generates a test signal applied to one or more of the above power lines; A signal detector that measures a detection signal returning after passing through one or more power lines with the above test signal; and An insulation monitoring device comprising a signal processor that calculates a composite insulation resistance representing the overall insulation state of the one or more power lines based on the above test signal, the above detection signal, and one or more internal resistances constituting the insulation monitoring device.
In claim 1, The above signal processor is, Based on the above test signal, the above detection signal, and the detection resistance for measuring the above detection signal, the composite insulation resistance before correction is obtained, and Based on the above test signal, the above detection signal, the above detection resistance, and the coupler resistance for receiving the above test signal, a theoretical composite insulation resistance is obtained, and An insulation monitoring device that obtains a calibration factor for correcting a measurement error of the insulation monitoring device based on the above-mentioned composite insulation resistance before correction and the above-mentioned theoretical composite insulation resistance.
In claim 2, The above signal processor is, An insulation monitoring device that calculates the calibration factor by dividing the theoretical composite insulation resistance by the composite insulation resistance before correction.
In claim 2, The above signal processor is, An insulation monitoring device that, when measuring the composite insulation resistance after obtaining the above calibration factor, obtains a corrected composite insulation resistance based on the composite insulation resistance before correction and the above calibration factor.
In claim 4, The above signal processor is, An insulation monitoring device that calculates the corrected composite insulation resistance by multiplying the above-mentioned composite insulation resistance before correction by the above-mentioned calibration factor.
In claim 1, The above insulation monitoring device further includes a signal coupler, and The above signal coupler is, An insulation monitoring device that maintains the insulation monitoring device in an insulated state from one or more power lines and transmits the test signal that has passed through one or more power lines to the signal detector.
In claim 6, The above signal coupler is, It includes one or more coupler resistors, The above signal processor is, An insulation monitoring device that calculates the composite insulation resistance by considering the above-mentioned coupler resistance as one of the above-mentioned internal resistances.
In claim 7, Each of the above one or more coupler resistors is connected in a one-to-one correspondence with the above one or more power lines, and The above signal detector is, It includes a detection resistor, The above detection signal is, An insulation monitoring device, wherein the voltage across the ends of the detection resistor is when the above test signal passes through the above power line, the above coupler resistor, and the above detection resistor.
In claim 8, The sum of the above composite insulation resistance and the above internal resistance is, An insulation monitoring device that is inversely proportional to the detection signal and proportional to the test signal or the detection resistance.
In claim 8, The above composite insulation resistance ( ) is an insulation monitoring device calculated by the following mathematical formula 1. (Mathematical Formula 1) : Composite insulation resistance : Test signal (applied voltage) : Detector : Detect signal (voltage across the terminals of the detection resistor) : Combined resistance of coupler resistance and detector resistance : Coupler resistor
In claim 1, Each of the above one or more power lines maintains an insulating state from the outside by means of an insulation resistance, and each of the above insulation resistances is connected in parallel to form the composite insulation resistance, and An insulation monitoring device in which a decrease in the above composite insulation resistance indicates that one or more of the above power lines have insulation breakdown.
A method of operation of an insulation monitoring device for monitoring the insulation status of one or more power lines, A step of generating a test signal applied to one or more power lines through a signal generator; A step of measuring a detection signal that returns after passing through one or more power lines through a signal detector, the test signal; and A method of operating an insulation monitoring device, comprising the step of calculating a composite insulation resistance representing the overall insulation state of one or more power lines based on the test signal, the detection signal, and one or more internal resistances constituting the insulation monitoring device through a signal processor.
In claim 12, The method of operation of the insulation monitoring device described above is, A step of obtaining a composite insulation resistance before correction based on the above test signal, the above detection signal, and a detection resistance for measuring the above detection signal; A step of obtaining a theoretical composite insulation resistance based on the above test signal, the above detection signal, the above detection resistance, and the coupler resistance for receiving the above test signal; and A method of operating an insulation monitoring device, further comprising the step of obtaining a calibration factor for correcting a measurement error of the insulation monitoring device based on the composite insulation resistance before correction and the theoretical composite insulation resistance.
In claim 13, The method of operation of the insulation monitoring device described above is, A method of operating an insulation monitoring device, further comprising the step of calculating the calibration factor by dividing the theoretical composite insulation resistance by the composite insulation resistance before correction.
In claim 12, The method of operation of the insulation monitoring device described above is, The method further includes the step of maintaining the insulation monitoring device in an insulated state from the one or more power lines through a signal coupler comprising one or more coupler resistors, and transmitting the test signal that has passed through the one or more power lines to the signal detector. The step of calculating the above composite insulation resistance is, A method of operation of an insulation monitoring device comprising the step of calculating the composite insulation resistance by considering the coupler resistance as one of the internal resistances.

Description

Insulation monitoring device to reduce measurement error of insulation resistance An embodiment of the present invention relates to an insulation monitoring device. Among electrical grounding systems, there is an insulation monitoring device in the primary insulation section of the low-voltage distribution system IT (Insulation Terra) grounding system to prevent electric shock and fire accidents caused by insulation breakdown. Isolated Terra (IT) grounding is a method in which neither end of the power line is grounded, and only the load enclosure is grounded. The primary reason for using this grounding method is the advantage of ensuring continuous operation without halting system operation, even if a fault occurs on one side of the power line. However, to obtain this advantage, it is necessary to continuously monitor the condition of the system's power lines using an insulation monitoring device. To continuously monitor the condition of the system's power lines, the calculated value of insulation resistance (Re) must be monitored using an insulation monitoring device. The insulation monitoring device for power line condition monitoring complies with the standards of IEC 61557. If the insulation resistance of power lines is not maintained and decreases, it can lead to economic losses such as equipment failure, electric shock, and fire accidents; therefore, the development of an insulation monitoring device that accurately measures insulation resistance is required. Figure 1 is a graph illustrating the error that occurs when measuring insulation resistance in a conventional insulation monitoring device. Referring to FIG. 1, the measured value and the theoretical value of the voltage across the detection resistor, which is measured to monitor the insulation status of a power line, may differ. Specifically, the insulation monitoring device may send a test signal to the power line to verify the insulation status and receive the test signal passing through the power line to use as a detection signal. At this time, the physical form of the test signal and the detection signal may be voltage. The insulation monitoring device can calculate the insulation resistance, which indicates the insulation status, from the voltage of the detection signal. In other words, the fact that the measured value of the detection signal measured by the insulation monitoring device differs from the theoretical value may mean that the measured value of the insulation resistance, which indicates the insulation status of the power line, differs from the theoretical value. Accordingly, an insulation resistance measuring device is required to provide an insulation resistance value by correcting the calibration value for error-causing factors. The present disclosure can be easily understood from the combination of the following detailed description and the accompanying drawings, where reference numerals denote structural elements. Figure 1 is a graph illustrating the error that occurs when measuring insulation resistance in a conventional insulation monitoring device. FIG. 2 is a drawing for explaining an insulation monitoring system according to one embodiment. FIG. 3 is a flowchart illustrating a method for an insulation monitoring device to measure composite insulation resistance according to one embodiment. FIG. 4 is a diagram illustrating the measurement of insulation resistance in an insulation monitoring device according to one embodiment. FIG. 5 is a block diagram illustrating a computing environment including a computing device suitable for use as an insulation monitoring device, according to one embodiment. Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The following detailed description is provided to facilitate a comprehensive understanding of the methods, apparatuses, and/or systems described herein. However, this is merely illustrative and the present invention is not limited thereto. In describing the embodiments of the present invention, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such detailed descriptions may unnecessarily obscure the essence of the present invention. Furthermore, the terms described below are defined in consideration of their functions within the present invention, and these may vary depending on the intentions or practices of the user or operator. Therefore, such definitions should be based on the content throughout this specification. Terms used in the detailed description are intended merely to describe the embodiments of the present invention and should not be limiting in any way. Unless explicitly stated otherwise, expressions in the singular form include the meaning of the plural form. In this description, expressions such as "include" or "comprise" are intended to refer to certain characteristics, numbers, steps, actions, elements, parts thereof, or combinations thereof