Insulation monitoring device and method for controlling insulation monitoring device

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.

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 a second voltage that is detected in the signal detection unit in a state where the coupler resistor and the detection resistor are connected by the circuit opening and closing switch contains a transient voltage, based on a first voltage that is detected in the signal detection unit in a state where the connection between the coupler resistor and the detection resistor is disabled by the circuit opening and closing switch, and to check the connected state of the insulating monitoring device to the transmission line and the ground, based on the result of detecting the transient voltage.

A method of controlling an insulating monitoring device including a circuit opening and closing switch enabling and disabling a connection between a coupler resistor connected to a transmission line and a preset detection resistor, and a signal detection unit including the preset detection resistor, the method comprising steps of:

• generating a measurement signal having a preset voltage and applying the measurement signal to the ground;
• disabling a connection between the coupler resistor and the preset detection resistor by controlling the circuit opening and closing switch;
• detecting an offset voltage based on a voltage detected in the signal detection unit, in a case where the connection between the coupler resistor and the preset detection resistor is disabled;
• connecting between the coupler resistor and the preset detection resistor by controlling the circuit opening and closing switch;
• and
• detecting whether or not the voltage detected through the signal detection unit contains a transient voltage, based on the offset voltage, and determining a connected state of the insulation monitoring device to the transmission line and the ground, based on whether or not the voltage detected through the signal detection unit contains the transient voltage.