Insulation monitoring device and method for controlling insulation monitoring device

Patent metadata

Field	Value
Publication number	US-2024353466-A1
Application number	US-202218683099-A
Country	US
Kind code	A1
Filing date	Oct 12, 2022
Priority date	Nov 15, 2021
Publication date	Oct 24, 2024
Grant date	—

Abstract

An insulation monitoring device comprises a signal generation unit generating a measurement signal having a preset voltage and applying the measurement signal to the ground; a signal detection unit including a coupler resistor connected to a transmission line and a detection resistor provided between the coupler resistor and the other end of the signal generation unit, and detecting the voltage of the measurement signal distributed to the internal resistance of the insulation monitoring device according to the voltage difference across the detection resistor; and a control unit detecting a transient voltage, due to the charging and discharging of a system capacitor and generated by parasitic capacitance between the transmission line and ground, from the voltage detected by the signal detection unit, and checking the connection state of the insulation monitoring device to the transmission line and ground based on the result of detecting the transient voltage.

First claim

1 . An insulation monitoring device for measuring an insulation resistance between a transmission line and the ground, the insulation monitoring device comprising:
a signal generation unit configured to generate a measurement signal having a preset voltage and to apply the measurement signal to the ground through a protective earth connected to one end thereof; a coupler resistor connected to the transmission line; a signal detection unit including a detection resistor provided between the coupler resistor and the other end of the signal generation unit and configured to detect a voltage of the measurement signal that is distributed to the internal resistance of the insulation monitoring device, the internal resistance being formed by the resistance of the coupler resistor and the resistance of the detection resistor according to a difference between voltages of both ends of the detection resistor; and a control unit configured to detect, from the voltage detected in the signal detection unit, a transient voltage due to charging and discharging of a system capacitor formed by parasite capacitance between the transmission line and the ground, and to check a connected state of the insulation monitoring device to the transmission line and the ground, based on the result of detecting the transient voltage.

2 . The insulation monitoring device of claim 1 , wherein the control unit detects a normal-state voltage from the voltage detected in the signal detection unit and detects, as the transient voltage, a voltage that is higher, by a preset magnitude or greater, than the detected normal-state voltage.

3 . The insulation monitoring device of claim 2 , wherein the control unit detects, with a period of the preset time, the transient voltage from the voltage detected in the signal detection unit, and the preset time is determined at least one of the following: a shape of the measurement signal or a period of the measurement signal.

4 . The insulation monitoring device of claim 2 , wherein the control unit determines sampling periods of time that vary with a preset time constant, computes average voltages of voltages that are detected in the signal detection unit during the sampling periods of time, respectively, and detects the normal-state voltage based on a difference between the computed average voltages.

5 . The insulation monitoring device of claim 2 , wherein, in a case where the voltage that is higher, by the preset magnitude or greater, than the normal-state voltage is detected, the control unit detects whether or not a magnitude of the detected voltage changes by a predetermined magnitude or greater for a predetermined time, and determines, further based on a change in the magnitude of the detected voltage, whether or not the transient voltage occurs.

6 . The insulation monitoring device of claim 1 , further comprising:
a communication unit configured to establish a connection to a preset server or terminal for communication, wherein, based on the result of detecting the transient voltage, the control unit controls the communication unit in such a manner as to transmit alerting information for alerting that the connected state of the insulation monitoring device is abnormal, to the server or terminal.

7 . A method of controlling an insulation monitoring device for measuring the resistance of an insulation resistance between a transmission line and the ground, the method comprising steps of:
generating a measurement signal having a preset voltage and applying the measurement signal to the ground; detecting, based on the resistance of a preset detection resistor, a voltage of the measurement signal that is distributed to the internal resistance of the insulation monitoring device, the internal resistance being formed by the resistance of a coupler resistor, connected to the transmission line, and the resistance of the detection resistor; determining whether or not a voltage detected through the detection resistor is a normal-state voltage; detecting whether or not a transient voltage occurs, from a voltage that is detected through the detection resistor for a preset time, in a case where the voltage detected through the detection resistor is the normal-state voltage; and determining a connected state of the insulation monitoring device to the transmission line and the ground, based on whether or not the transient voltage occurs.

8 . The method of claim 7 , wherein the step of detecting whether or not the transient voltage occurs comprises steps of:
computing a voltage difference between the voltage detected through the detection resistor and the normal-state voltage; comparing the computed voltage difference and a voltage value of preset magnitude; determining that the transient voltage occurs, in a case where, as a result of the comparison, the computed voltage difference is at or above the voltage value of preset magnitude; and determining that the transient voltage does not occur, in a case where, as a result of the comparison, the computed voltage difference is below the voltage value of preset magnitude.

9 . The method of claim 7 , wherein the step of determining whether or not the voltage detected through the detection resistor is the normal-state voltage comprises steps of:
determining a sampling period of time that varies with a preset time constant; computing an average voltage of voltages that are detected during the sampling periods of time; computing a difference between the average voltage and an average voltage of voltages that are detected during the preceding sampling period of time; comparing the computed difference and a preset error; and determining, as the normal-state voltage, the average voltage of the voltages detected during the sampling period of time, or reperforming the step of computing the sampling period of time, the step of computing the average voltage, the step of computing the difference between the average voltages, and the step of comparing the computed difference and the preset error, based on the result of the comparison.

10 . The method of claim 7 , wherein the step of determining the connected state of the insulation monitoring device to the transmission line and the ground comprises a step of:
transmitting alerting information for alerting that the connected state of the insulation monitoring device is abnormal, to a preset server or terminal, in a case where the transient voltage does not occur for the preset time.

11 . An insulation monitoring device for measuring the resistance of an insulation resistance between a transmission line and the ground, the insulation monitoring device comprising:
a signal generation unit configured to generate a measurement signal having a preset voltage and to apply the measurement signal to the ground through a protective earth connected to one end thereof; a coupler resistor connected to the transmission line; a signal detection unit including a detection resistor provided between the coupler resistor and the other end of the signal generation unit and configured to detect a voltage of the measurement signal that is distributed to the internal resistance of the insulation monitoring device, the internal resistance being formed by the resistance of the coupler resistor and the resistance of the detection resistor according to a difference between voltages of both ends of the detection resistor; a circuit opening and closing switch configured to connect between the coupler resistor and the detection resistor and to disable a connection between the coupler resistor and the detection resistor; and a control unit configured to control the circuit opening and closing switch, to detect whether or not

Assignees

• Ls Electric Co Ltd

Inventors

• YOON Jaeshik

Classifications

• G01R31/66

  Testing of connections, e.g. of plugs or non-disconnectable joints (testing for incorrect line connections G01R31/55) · CPC title

• G01R31/2841

  Signal generators · CPC title

• G01R27/025

  Measuring very high resistances, e.g. isolation resistances, i.e. megohm-meters · CPC title

• G01R19/16576

  comparing DC or AC voltage with one threshold (G01R19/16514, G01R19/16519, G01R19/16528, G01R19/16533 and G01R19/1659 take precedence) · CPC title

• G01R19/003

  Measuring mean values of current or voltage during a given time interval · CPC title