KR20230092476A - Insulation monitoring device with high impedance it system conversion function modified in dc system and method thereof - Google Patents

Abstract

The present invention relates to an insulation monitoring device having a modified high-impedance IT grid conversion function in a DC system and a method thereof, wherein a voltage measurement unit measures a voltage of each of a positive resistor terminal and a negative resistor terminal connected to a circuit, a resistance control unit connects and disconnects a load resistor to any one of the positive resistor terminal and the negative resistor terminal according to the measured voltage value of each resistor terminal, an insulation status determination unit derives an insulation resistance of the circuit from a resistance value of each resistor terminal and the measured voltage value of each resistor terminal before and after the connection of the load resistor to determine an insulation status of each resistor, thereby suppressing a rise of an earth potential of a system device and minimizing an electrolytic corrosion phenomenon of a ground electrode due to deterioration of insulation performance.

Description

Insulation monitoring device with high impedance IT system conversion function in DC system and method for it

The present invention relates to an insulation monitoring device having a high-impedance IT system conversion function modified from a DC system and a method therefor, and to a technology enabling real-time monitoring of insulation breakdown in a DC system with high impedance.

With the expansion of DC power generation sources and DC loads, the efficiency of DC distribution systems has been verified in terms of energy power conversion efficiency, and users' demands for DC distribution are increasing.

This is a solution that can solve power quality and energy efficiency problems, but its use has been extremely limited so far due to the lack of technical environment for electrical safety, such as grounding technology and fault detection and blocking technology.

Conventional direct current distribution has been conducted mainly for performance verification and technology development, such as linked operation of developed devices, and is insufficient in terms of securing safety according to tests for various environments such as load simulation and system simulation.

Currently, most low-voltage DC systems such as photovoltaic power generation facilities and ESS use non-grounded systems, which are IT systems, and when installed indoors, such as DC power distribution for customers, the site defined by the Electrical Equipment Technical Standards for electric shock protection It is composed of voltage less than 300V.

In addition, from the point of view of electrical safety, the electrical corrosion problem caused by insulation deterioration, which is a disadvantage of low voltage direct current distribution, is stipulated to prevent electrical corrosion through chemical treatment of the ground electrode during grounding work, but the fundamental problem has not been solved. Insulation monitoring devices for facility protection are limited to photovoltaic power generation facilities and ESSs, so there is a concern that accidents may occur while remaining as recommendations for low-voltage direct current distribution for consumers that are easily accessible to users.

Therefore, it appears advantageous to use a midline power supply and grounding system in order to secure electrical safety such as limitation of use voltage due to limitation of ground voltage of low voltage direct current distribution for customers, electric shock protection, and protection against electric shock.

However, as industrialization is hindered due to economic issues when applying a power converter using a midline, a low voltage DC system to solve technical and economic problems requires a technology that converts an IT system to an IN system, and thus electric shock to the human body. It is necessary to develop a technology to monitor insulation for protection.

Republic of Korea Patent Publication No. 10-2020-0052688 (2020.05.15)

The present invention can provide an insulation monitoring device having a high-impedance IT system conversion function transformed from a DC system that can prevent safety accidents through insulation monitoring through a change in ground resistance of an IN system, and a method therefor. .

Insulation monitoring device having a high-impedance IT system conversion function in a DC system according to an aspect of the present invention is a voltage measurement unit for measuring voltages of each of the positive resistance terminal and the negative resistance terminal connected to the circuit; a resistance control unit that connects and disconnects a load resistor from one of the positive resistance terminal and the negative resistance terminal according to the measured voltage value of each resistance terminal; and an insulation state determination unit for determining the insulation state of each resistance stage by deriving the insulation resistance of the circuit from the measured voltage value of each resistance stage before and after connection of the load resistance and the resistance value of each resistance stage. .

Preferably, the positive resistance terminal may include at least one resistor in a circuit to which a positive voltage is applied.

Preferably, the negative resistance terminal may include at least one resistor in a circuit to which a negative voltage is applied.

Preferably, a plurality of resistors may be connected in parallel to each of the positive resistance terminal and the negative resistance terminal.

Preferably, the resistance control unit connects a load resistance to the negative resistance terminal when the measured voltage value of the positive resistance terminal is greater than or equal to the measured voltage value of the negative resistance terminal, and the measured voltage value of the positive resistance terminal is A load resistor may be connected to the positive resistance terminal if the voltage is less than the measured voltage value of the negative resistance terminal.

Preferably, the load resistor may have a resistance value smaller than that of any one of the positive resistance end and the negative resistance end.

Preferably, the insulation state may be an insulation breakdown state due to human body contact, a sudden voltage drop, and a ground fault.

Preferably, the insulation state determination unit receives a voltage value of each resistance terminal measured after a load resistance is connected to any one of the positive resistance terminal and the negative resistance terminal, and determines the ratio of the voltage values of each resistance terminal. The insulation state of the circuit can be continuously monitored by comparing the derived insulation resistance of each resistance stage.

Preferably, the resistance controller separates the load resistance connected to the negative resistance terminal when the ratio of the voltage values of the respective resistance terminals is lower than the derived insulation resistance of the positive resistance terminal, and then connects the load resistance to the positive resistance terminal. And, if the ratio of the voltage values of each resistance terminal is lower than the derived insulation resistance of the negative resistance terminal, the load resistance connected to the positive resistance terminal may be disconnected and then the load resistance may be connected to the negative resistance terminal.

An insulation monitoring method of an insulation monitoring device having a high impedance IT system conversion function in a DC system according to another aspect of the present invention is a voltage measurement step of measuring the voltage of each of the positive resistance terminal and the negative resistance terminal connected to the circuit by the voltage measuring unit. ; a resistance control step in which a resistance controller connects and disconnects a load resistor from one of the positive resistance terminal and the negative resistance terminal according to the measured voltage value of each resistance terminal; and an insulation state determination step in which an insulation state determination unit determines the insulation state of each resistance stage by deriving the insulation resistance of the circuit from the measured voltage value of each resistance stage before and after connection of the load resistance and the resistance value of each resistance stage. can include

Preferably, in the resistance control step, when the measured voltage value of the positive resistance terminal is greater than or equal to the measured voltage value of the negative resistance terminal, a load resistance is connected to the negative resistance terminal, and the measured voltage value of the positive resistance terminal If the voltage is less than the measured voltage value of the negative resistance terminal, a load resistor may be connected to the positive resistance terminal.

Preferably, in the step of determining the insulation state, after a load resistance is connected to one of the positive resistance terminal and the negative resistance terminal, the measured voltage value of each resistance terminal is received and the ratio of the voltage values of each resistance terminal is received. The insulation state of the circuit can be continuously monitored by comparing the insulation resistance of each resistance stage with the insulation resistance of each resistance stage.

Preferably, in the resistance control step, when the ratio of the voltage values of the respective resistance ends is lower than the insulation resistance of the positive resistance end, the load resistance connected to the negative resistance end is disconnected, and then the load resistance is connected to the positive resistance end. , If the ratio of the voltage values of each resistance terminal is lower than the insulation resistance of the negative resistance terminal, the load resistance connected to the positive resistance terminal may be disconnected and then the load resistance may be connected to the negative resistance terminal.

According to the present invention, it is possible to suppress an increase in the ground potential of a DC distribution system device and to minimize an electroporation phenomenon of a ground electrode due to a decrease in insulation performance.

1 is a configuration diagram of an insulation monitoring device according to an embodiment.
2 is an overall circuit diagram of an insulation monitoring device according to an embodiment.
3 is a circuit diagram showing a general state of an insulation monitoring device according to an embodiment.
4 is a circuit diagram in a state in which a voltage of a positive resistance terminal is high according to an exemplary embodiment.
5 is a circuit diagram in a state in which a voltage of a negative resistance terminal is high according to an exemplary embodiment.
6 is a flowchart illustrating a ground conversion method according to an exemplary embodiment.

Hereinafter, an insulation monitoring device having a modified high impedance IT system conversion function in a DC system according to the present invention and a method therefor will be described in detail with reference to the accompanying drawings. In this process, the thickness of lines or the size of components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to an operator's intention or practice. Therefore, definitions of these terms will have to be made based on the content throughout this specification.

The objects and effects of the present invention can be naturally understood or more clearly understood by the following description, and the objects and effects of the present invention are not limited only by the following description. In addition, in describing the present invention, if it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

1 is a configuration diagram of an insulation monitoring device according to an embodiment.

As shown in FIG. 1 , the configuration of the insulation monitoring device according to an embodiment may include a voltage measurement unit 100, a resistance control unit 300, and an insulation state determination unit 500.

The voltage measuring unit 100 may measure voltages of the positive resistance terminal 20 and the negative resistance terminal 30 connected to the circuit.

The resistance control unit 300 may connect and disconnect a load resistor from one of the positive resistance terminal 20 and the negative resistance terminal 30 according to the measured voltage value of each resistance terminal.

The insulation state determination unit 500 can determine the insulation state of each resistance stage by deriving the insulation resistance of the circuit from the measured voltage value of each resistance stage before and after connection of the load resistance and the resistance value of each resistance stage. there is.

Here, the positive resistance stage 20 may be one in which at least one resistor is provided in a circuit to which a positive voltage is applied, and the negative resistance stage 30 may be one in which at least one resistor is provided in a circuit to which a negative voltage is applied. there is.

In addition, each of the positive resistance terminal 20 and the negative resistance terminal 30 may have a plurality of resistors connected in parallel.

In addition, when the measured voltage value of the positive resistance terminal 20 is greater than or equal to the measured voltage value of the negative resistance terminal 30, the resistance controller 300 connects a load resistance to the negative resistance terminal 30 and , When the measured voltage value of the positive resistance terminal 20 is less than the measured voltage value of the negative resistance terminal 30, a load resistor may be connected to the positive resistance terminal 20.

Here, the load resistance may have a smaller resistance value than any one of the positive resistance stage 20 and the negative resistance stage 30, and the insulation state is an insulation breakdown state due to human body contact, a sudden voltage drop, and a ground fault. can be

The insulation state determining unit 500 receives the measured voltage value of each resistance terminal after the load resistance is connected to one of the positive resistance terminal 20 and the negative resistance terminal 30, and determines the value of each resistance terminal. The insulation state of the circuit can be continuously monitored by comparing the ratio of the voltage values with the insulation resistance of each resistance stage.

At this time, the resistance controller 300 changes the voltage value of each resistance stage. If the ratio is lower than the insulation resistance of the positive resistance terminal 20, the load resistance connected to the negative resistance terminal 30 is disconnected, and then the load resistance is connected to the positive resistance terminal 20, and the voltage value of each resistance terminal If the ratio of is lower than the insulation resistance of the negative resistance terminal 30, the load resistance connected to the positive resistance terminal 20 may be disconnected and then the load resistance may be connected to the negative resistance terminal 30.

2 is an overall circuit diagram of an insulation monitoring device according to an embodiment.

As shown in FIG. 2, the overall circuit diagram of the insulation monitoring device according to an embodiment includes a power supply 10, a positive resistance terminal 20, a negative resistance terminal 30, a load 11, and a ground terminal 12. It may be composed of, and may include a load resistor provided in parallel with the plus resistance stage 20. The load resistor may include a first load resistor 40, a second load resistor 50, a third cupping resistor, and a fourth load resistor 70, but the load resistor is not necessarily limited to the above-described number. .

In addition, each of the positive resistance end 20, the negative resistance end 30, the first load resistance 40, the second load resistance 50, the third load resistance 60, and the fourth load resistance 70 It can be connected to the ground terminal 12 .

Here, the first load resistance 40 and the third load resistance 60 may be connected in parallel to the positive resistance terminal 20, and the second load resistance 50 and the fourth load resistance 70 may be connected to the negative resistance terminal. (30) can be connected in parallel.

At this time, each of the third load resistor 60 connected in parallel to the positive resistance terminal 20 and the fourth load resistor 70 connected in parallel to the negative resistance terminal 30 corresponds to the voltage value measured at each resistance terminal. Accordingly, any one of the third load resistor 60 and the fourth load resistor 70 may be connected and disconnected.

3 is a circuit diagram showing a general state of an insulation monitoring device according to an embodiment.

As shown in FIG. 3, the general state of the insulation monitoring device according to an embodiment is each of the first load resistor 40, the second load resistor 50, and the third load resistor 60 provided in the resistance control unit 300. ), and the fourth load resistor 70, the first load resistor 40 and the second load resistor 50 are connected to the ground terminal 12, and the third load resistor 60 and the fourth load resistor 70 ) may be in an open state.

At this time, while the third load resistor 60 and the fourth load resistor 70 are open, the voltages of the positive resistance terminal 20 and the negative resistance terminal 30 are measured and the measured voltages are compared. If the voltage (V _P ) of the positive resistance terminal 20 is higher than the voltage (V _N ) of the negative resistance terminal 30, the fourth load resistor 70 connected in parallel to the negative resistance terminal 30 is can connect

In addition, while the third load resistor 60 and the fourth load resistor 70 are open, the voltages of the plus resistance terminal 20 and the minus resistance terminal 30 are measured and the measured voltages are compared. If the voltage (V _P ) of the positive resistance terminal 20 is less than the voltage (V _N ) of the negative resistance terminal 30, the third load resistor 60 may be connected to the positive resistance terminal 20.

It is a device for converting the IT system to the IN system to secure the electrical safety of the low voltage DC system. It has an insulation monitoring function using high impedance, which is an essential element for IN system conversion. 2, and by reducing the leakage current due to insulation deterioration, it is possible to minimize the electrocution phenomenon according to the limit of the current flowing to the ground, and to protect the human body from electric shock when interlocking with a protective device such as a circuit breaker through insulation monitoring and to secure the safety of facilities Direct current distribution activation is possible.

4 is a circuit diagram in a state in which a voltage of a positive resistance terminal is high according to an embodiment, and FIG. 5 is a circuit diagram in a state in which a voltage of a negative resistance terminal is high according to an embodiment.

As shown in FIGS. 4 and 5 , if the voltage of the positive resistance terminal 20 is high among the voltage values measured at each resistance terminal, the fourth load resistor 70 may be connected to the negative resistance terminal 30, and each resistance If the voltage of the positive resistance terminal 20 is higher than the voltage of the negative resistance terminal 30 among the voltage values measured at the terminal, the third load resistor 60 may be connected to the positive resistance terminal 20 .

이고, 마이너스 저항단(30)에 대한 절연저항은

이며, IN 계통변환을 위한 고임피던스인 제1 부하저항(40) 및 제2 부하저항(50) 각각은

이고, 절연저항 도출을 위한 제3 부하저항(60) 및 제4 부하저항(70) 각각은

이며, 플러스 저항단(20)과 제1 부하저항(40)의 합성 병렬 절연저항인 플러스 저항단(20)의 합성 절연저항(

) 및 마이너스 저항단(30)과 제2 부하저항(50)의 합성 병렬 절연저항인 마이너스 저항단(30)의 합성 절연저항(

) 각각은 다음 수학식으로 표현될 수 있다.At this time, the insulation resistance for the positive resistance stage 20 is

And, the insulation resistance for the negative resistance stage 30 is

And, each of the first load resistor 40 and the second load resistor 50, which are high impedance for IN system conversion, is

And, each of the third load resistor 60 and the fourth load resistor 70 for deriving the insulation resistance is

And, the combined insulation resistance of the plus resistance stage 20, which is the combined parallel insulation resistance of the plus resistance stage 20 and the first load resistance 40 (

) and the composite insulation resistance of the negative resistance stage 30, which is the combined parallel insulation resistance of the negative resistance stage 30 and the second load resistance 50 (

) Each can be expressed by the following equation.

[Equation 1]

[Equation 2]

In Equations 1 and 2, V _P and V _N are the voltage values of the positive resistance terminal 20 and the voltage value of the negative resistance terminal 30 measured before the fourth load resistor 70 is connected, respectively, and V _P ' is a voltage value of the positive resistance terminal 20 measured after the fourth load resistor 70 is connected, and V _DC is a direct current voltage. The insulation resistance of the positive resistance terminal 20 and the insulation resistance of the negative resistance terminal 30 are the voltage values of each resistance terminal measured with the third load resistance 60 and the fourth load resistance 70 open. In comparison, as the voltage value of the positive resistance terminal 20 is measured to be high, the fourth load resistor 70 may be connected to the negative resistance terminal 30 . At this time, the combined insulation resistance of each resistance stage in the state in which the fourth load resistor 70 is connected can be derived.

Here, when the voltage value of each resistance terminal measured in the open state of the third load resistor 60 and the fourth load resistor 70 is compared, if the voltage value of the negative resistance terminal 30 is high, the following equation can be derived through

[Equation 3]

[Equation 4]

In Equations 3 and 4, V _N is the voltage value of the negative resistance terminal 30 measured before the third load resistor 60 is connected, and V _N 'is after the third load resistor 60 is connected. This is the measured voltage value of the negative resistance terminal 30.

At this time, the combined insulation resistance of the positive resistance stage 20 represents the combined resistance of the insulation resistance of the positive resistance stage 20 and the first load resistance 40, and the combined insulation resistance of the negative resistance stage 30 is the negative resistance stage. Since (30) represents the combined resistance of the second load resistor 50, the insulation resistance of each resistance stage can be expressed by the following equation.

[Equation 5]

[Equation 6]

는 제3 부하저항(60) 및 제4 부하저항(70)이 오픈된 상태에서 측정된 각 저항단의 전압값 중 플러스 저항단(20)의 전압값이 높은 경우의 플러스 저항단(20)에 대한 절연저항을 나타낸 것이고, 수학식 6에서,

는 제3 부하저항(60) 및 제4 부하저항(70)이 오픈된 상태에서 측정된 각 저항단의 전압값 중 마이너스 저항단(30)의 전압값이 높은 경우의 마이너스 저항단(30)에 대한 절연저항을 나타낸 것이다.In Equation 5,

In the positive resistance stage 20 when the voltage value of the plus resistance stage 20 is high among the voltage values of each resistance stage measured with the third load resistor 60 and the fourth load resistor 70 open Insulation resistance is shown, and in Equation 6,

In the negative resistance stage 30 when the voltage value of the negative resistance stage 30 is high among the voltage values of each resistance stage measured with the third load resistor 60 and the fourth load resistor 70 open represents the insulation resistance.

At this time, when the insulation resistance value of each resistance stage is integrated, it can be expressed by the following equation.

[Equation 7]

는 전체 합성 절연저항이다. 플러스 저항단(20) 및 마이너스 저항단(30) 중 어느 하나의 저항단에 부하저항이 연결된 후, 각 저항단의 전압을 재측정하여 측정된 전압값의 비와 각 저항단의 절연저항으로 절연상태에 대한 지속적인 모니터링을 할 수 있으며, 이는 다음 수학식으로 표현될 수 있다.In Equation 7,

is the total composite insulation resistance. After the load resistance is connected to either one of the positive resistance terminal 20 and the negative resistance terminal 30, the voltage of each resistance terminal is re-measured, and the insulation resistance is determined by the ratio of the measured voltage value and the insulation resistance of each resistance terminal. Continuous monitoring of the state can be performed, which can be expressed by the following equation.

[Equation 8]

[Equation 9]

In Equation 8, V _P 'and V _N 'are the voltage value and the negative resistance of the positive resistance terminal 20 measured in the state in which the fourth load resistor 70 is connected to the negative resistance terminal 30 among each resistance terminal, respectively. It is the voltage value of the terminal 30, and in the state where the fourth load resistance 70 is connected to the negative resistance terminal 30, the value of V _P '/V _N ' is the combined insulation resistance of the positive resistance terminal 20 and the fourth load If it is smaller than the value obtained by dividing the sum of the resistances 70 by the fourth load resistance 70, the fourth load resistance 70 connected to the negative resistance terminal 30 is disconnected and the third load resistance ( 60) can be connected.

In addition, in Equation 9, the voltage value V _P '/V _N ' of each resistance terminal measured in a state in which the third load resistor 60 is connected to the positive resistance terminal 20 is the synthesis of the negative resistance terminal 30 If the sum of the insulation resistance and the third load resistance 60 is smaller than the value divided by the third load resistance 60, the third load resistance 60 connected to the positive resistance terminal 20 is separated and the negative resistance terminal 30 A fourth load resistor 70 can be connected to.

At this time, a current sensing device 80 may be included to detect the current flowing to the ground line, and the current detected from the current sensing device 80 detects a sudden insulation failure that appears like a complete ground fault, and the previously detected insulation resistance. It can be used to detect a secondary accident such as a human electric shock by comparing the detected leakage current value.

As an analysis of the fault loop for the midpoint IN grounding method, it shows the characteristics of the positive and negative ground faults on the load side. In case of insulation failure, it shows that the fault current changes from the change in parallel resistance due to human contact depending on whether or not the human body is contacted. At this time, according to the fault loop analysis, the parallel resistance (B) due to the human body contact can be expressed by the following equation.

[Equation 10]

In Equation 10, B is parallel resistance due to human body contact, Z _G , Z _{B ,} and Z _PE are impedance resistances, respectively, and the fault current according to the presence or absence of human body contact can be divided into the following Table 1 according to the positive and negative electrodes. .

load-side ground fault Fault current when no contact [A] Human body energization current when touching the enclosure [A] anode

cathode

In order to analyze the characteristics according to the high resistance impedance change, the high resistance impedance value is configured as a multiple of 10 in the range of 0.1 ~ 100 [kΩ], and in the case of human body resistance, 1 [kΩ], and in the case of load resistance, any steady-state load current is set to 5 Calculated by [A] and selected as 76 [Ω], the results of analysis under the same conditions are shown in Table 2.

load-side ground fault Fault current when no contact [mA] Human body energization current upon contact [mA] Human body current direction when energized Z _M [kΩ] Z _M [kΩ] 0.1[kΩ] 1[kΩ] 10[kΩ] 100[kΩ] 0.1[kΩ] 1[kΩ] 10[kΩ] 100[kΩ] anode 3778.0 379.80 38.0 3.80 1.861 0.187 0.019 0.002 downward cathode -3778.0 -379.80 -38.0 -3.80 -1.861 -0.187 -0.019 -0.002 lift

As shown in Table 2, when using an IN system converter with an insulation monitoring function, it is possible to analyze secondary accidents such as human electric shock protection, insulation monitoring, and human electric shock by reducing the ground voltage of low-voltage direct current distribution for customers installed indoors. It is possible to secure safety and reliability of safety technology in the DC field, and based on this, it is possible to activate the DC industry and create profits.

6 is a flowchart illustrating a ground conversion method according to an exemplary embodiment.

As shown in FIG. 6 , the ground conversion method according to an embodiment may include a voltage measurement step ( S100 ), a resistance control step ( S300 ), and an insulation state determination step ( S500 ).

In the voltage measuring step ( S100 ), the voltage measuring unit 100 may measure voltages of the positive resistance terminal 20 and the negative resistance terminal 30 connected to the circuit.

In the resistance control step (S300), the resistance control unit 300 connects a load resistance to one of the positive resistance terminal 20 and the negative resistance terminal 30 according to the measured voltage value of each resistance terminal, and can be separated

Here, in the resistance control step (S300), when the measured voltage value of the positive resistance terminal 20 is greater than or equal to the measured voltage value of the negative resistance terminal 30, a load resistance is connected to the negative resistance terminal 30, When the measured voltage value of the positive resistance terminal 20 is less than the measured voltage value of the negative resistance terminal 30, a load resistor may be connected to the positive resistance terminal 20.

In the insulation state determination step (S500), the insulation state determination unit 500 derives the insulation resistance of the circuit from the measured voltage value of each resistance terminal before and after connection of the load resistance and the resistance value of each resistance terminal, and each resistance The insulation state of the stage can be judged.

Here, in the insulation state determination step (S500), after the load resistance is connected to any one resistance end of the positive resistance end 20 and the negative resistance end 30, the measured voltage value of each resistance end is transferred to each resistance end. The insulation state of the circuit can be continuously monitored by comparing the ratio of the voltage values of and the insulation resistance of each resistance stage. At this time, in the resistance control step (S300), if the ratio of the voltage values of the respective resistance stages is lower than the insulation resistance of the positive resistance stage 20, after separating the load resistance connected to the negative resistance stage 30, the positive resistance stage A load resistance is connected to (20), and if the ratio of the voltage values of the respective resistance ends is lower than the insulation resistance of the negative resistance end (30), the load resistance connected to the positive resistance end (20) is separated and the negative resistance A load resistor may be connected to the stage 30.

Although the present invention has been described in detail through representative embodiments, those skilled in the art will understand that various modifications are possible to the above-described embodiments without departing from the scope of the present invention. will be. Therefore, the scope of the present invention should not be limited to the described embodiments and should not be defined, and should be defined by all changes or modified forms derived from the claims and equivalent concepts as well as the claims to be described later.

100: voltage measurement unit 300: resistance control unit
500: insulation state determination unit
10: power supply 11: load
12: ground terminal
20: positive resistance end 30: negative resistance end
40: first load resistance 50: second load resistance
60: 3rd load resistance 70: 4th load resistance
80: current sensing device

Claims (13)

a voltage measurement unit for measuring voltages of each of the positive resistance terminal and the negative resistance terminal connected to the circuit;
a resistance control unit that connects and disconnects a load resistor from one of the positive resistance terminal and the negative resistance terminal according to the measured voltage value of each resistance terminal; and
In a DC system including an insulation state determination unit for determining the insulation state of each resistance stage by deriving the insulation resistance of the circuit from the measured voltage value of each resistance stage before and after connection of the load resistance and the resistance value of each resistance stage Insulation monitoring device with modified high-impedance IT grid conversion function.
According to claim 1,
The positive resistance stage is an insulation monitoring device having a high impedance IT system conversion function transformed from a DC system, characterized in that at least one resistor is provided in the circuit to which the positive voltage is applied.
According to claim 1,
The negative resistance stage is an insulation monitoring device having a high impedance IT system conversion function transformed from a DC system, characterized in that at least one resistor is provided in the circuit to which a negative voltage is applied.
According to claim 1,
Insulation monitoring device having a high impedance IT system conversion function transformed from a DC system, characterized in that each of the plus resistance stage and the minus resistance stage has a plurality of resistors connected in parallel.
According to claim 1,
The resistance control unit connects a load resistance to the negative resistance terminal when the measured voltage value of the positive resistance terminal is greater than or equal to the measured voltage value of the negative resistance terminal, and the measured voltage value of the positive resistance terminal is equal to or greater than the measured voltage value of the negative resistance terminal. Insulation monitoring device having a high impedance IT system conversion function transformed from a DC system, characterized in that for connecting the load resistance to the positive resistance terminal if it is less than the measured voltage value of.
According to claim 1,
The load resistance is an insulation monitoring device having a high impedance IT system conversion function transformed from a DC system, characterized in that the resistance value is smaller than any one of the positive resistance end and the negative resistance end.
According to claim 1,
The insulation monitoring device having a high impedance IT system conversion function transformed from a DC system, characterized in that the insulation state is an insulation breakdown state due to human contact, sudden voltage drop, and ground fault.
According to claim 1,
The insulation state determining unit receives the measured voltage value of each resistance terminal after a load resistance is connected to one of the positive resistance terminal and the negative resistance terminal, and calculates the ratio between the voltage value of each resistance terminal and each resistance terminal. Insulation monitoring device having a transformed high impedance IT system conversion function in a DC system, characterized in that it continuously monitors the insulation state of the circuit by comparing the insulation resistance.
According to claim 8,
The resistance controller separates the load resistance connected to the negative resistance terminal when the ratio of the voltage values of the respective resistance terminals is lower than the insulation resistance of the positive resistance terminal, and then connects the load resistance to the positive resistance terminal, and connects the load resistance to the respective resistance terminals. If the ratio of the voltage values of is lower than the insulation resistance of the negative resistance terminal, the high impedance IT system modified from the DC system, characterized in that the load resistance connected to the positive resistance terminal is disconnected and then the load resistance is connected to the negative resistance terminal. Insulation monitoring device with conversion function.
a voltage measurement step of measuring voltages of each of the positive resistance terminal and the negative resistance terminal connected to the circuit by the voltage measuring unit;
a resistance control step in which a resistance controller connects and disconnects a load resistor from one of the positive resistance terminal and the negative resistance terminal according to the measured voltage value of each resistance terminal; and
An insulation state determination step of determining the insulation state of each resistance stage by deriving the insulation resistance of the circuit with the measured voltage value of each resistance stage and the resistance value of each resistance stage before and after the connection of the load resistance by the insulation state determination unit. Insulation monitoring method of an insulation monitoring device having a transformed high impedance IT system conversion function in a DC system including
According to claim 10,
In the resistance control step, when the measured voltage value of the positive resistance terminal is greater than or equal to the measured voltage value of the negative resistance terminal, a load resistance is connected to the negative resistance terminal, and the measured voltage value of the positive resistance terminal is the negative resistance. Insulation monitoring method of an insulation monitoring device having a modified high impedance IT system conversion function in a DC system, characterized in that the load resistance is connected to the positive resistance terminal if it is less than the measured voltage value of the terminal.
According to claim 10,
In the step of determining the insulation state, after a load resistance is connected to one of the positive resistance terminal and the negative resistance terminal, the measured voltage value of each resistance terminal is received, and the ratio of the voltage value of each resistance terminal to each resistance terminal Insulation monitoring method of an insulation monitoring device having a transformed high impedance IT system conversion function in a DC system, characterized in that the insulation state of the circuit is continuously monitored by comparing the insulation resistance of the insulation.
According to claim 12,
In the resistance control step, when the ratio of the voltage values of each resistance terminal is lower than the insulation resistance of the positive resistance terminal, the load resistance connected to the negative resistance terminal is separated, and then the load resistance is connected to the positive resistance terminal, and each resistance If the ratio of the voltage values of the terminal is lower than the insulation resistance of the negative resistance terminal, the load resistance connected to the positive resistance terminal is separated and then the load resistance is connected to the negative resistance terminal. Insulation monitoring method of insulation monitoring device with system conversion function.

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