KR102495186B1 - Electrical apparatus and method for measuring leakage state of each concent multiply connected to source - Google Patents

Abstract

The present invention discloses a method, in which when multiple outlets are connected to a ground-separated power source, an insulation state between the ground and power source of a load connected to each outlet is diagnosed for each outlet, so a user can quickly respond to a risk of an electric shock or a fire due to ground insulation breakdown. The implementation according to the present invention may be installed independently between the outlet and the load or may be manufactured integrally with the outlet.

Description

Electrical device and method for measuring the leakage state of loads connected to multiple outlets

The present invention relates to an electric device and method for measuring the leakage state of a load connected to a plurality of outlets, and more particularly, to an electrical device and method for measuring the ground insulation state of a load connected to a plurality of outlets branched from a ground-insulated power supply independently for each outlet. It relates to an electrical device and method for diagnosing and providing protection from electric shock and fire through warning in case of an abnormality.

In particular, an object of the present invention is to provide an outlet capable of quick action by determining and notifying the load insulation state of a specific outlet among a plurality of outlets.

A power supply is a device that supplies power to a predetermined electrical device or facility.

In Korea, the power provided by Korea Electric Power Corporation is usually a 3-phase 4-wire type, and the line-to-line voltage at the final stage is usually 380V, and the voltage between the line and the neutral line is 220V. In this case, the neutral wire is usually made to have the same potential as the ground.

Electrical devices are grounded for safety to protect the device when a short circuit occurs and to eliminate the risk that may be caused by a short circuit.

In addition, various technologies have been developed for preventing the occurrence of electric shock or fire, which may be caused by a short circuit or a problem in a power supply system, as described above in a conventional power supply device, and examples thereof include Patent Documents 1 to 4. .

Patent Document 1 is an electrical device that senses input power supplied to an insulated load and detects and informs an electric shock or fire due to a short circuit when an insulated electrical device fails, and includes first and second selection switches in series with each input power source. Through the first and second distribution resistors, the first and second insulation amplifiers for measuring the voltages divided by the first and second distribution resistors, the voltage detected by the first and second insulation amplifiers and the reference voltage generator An electric device including first and second comparators for comparison, an adder for summing the results of the first and second comparators, and an output switch for outputting the result of the adder,

Patent Document 2 discloses a first current having a reference point connected to both electrodes of the battery unit and generating a reference voltage according to a potential difference between the two electrodes in a leakage detection circuit of a power supply device having a battery unit composed of a plurality of batteries. path, and a second current path connected to both electrodes of the battery unit, having three points having different potentials, and a middle point of the three points connected to ground through an insulation resistance, and a midpoint of the second current path The first and second comparators receiving the voltage applied from each of the two points placed to one input terminal and the reference voltage applied from the reference point of the first current path to the other input terminal, and to the output of the first and second comparators An earth leakage detection circuit of a power supply device including a detection circuit for detecting occurrence of an earth leakage based on the

Patent Document 3 includes an input port to which an output terminal of a first phase current transformer is connected, an output port to which an input terminal of a first circuit breaker is connected, a first determiner including a first LAN port and a second LAN port; a second determiner including an input port to which the output terminal of the second phase current transformer is connected, an output port to which the input terminal of the second circuit breaker is connected, a first LAN port, and a second LAN port; and a main unit connected to the first LAN port of the first determiner by any one LAN cable, wherein the second LAN port of the first determiner and the first LAN port of the second determiner are connected to different LAN cables. connected by, and each of the first judger and the second judger analyzes the signal input to the input port and outputs a cut-off signal to the output port when it is determined that there is a leakage, and the main unit is the first judger and the second judger It is an earth leakage blocking system that monitors the status,

Patent Document 4 discloses at least one end electrically connected to at least one of two or more power lines insulated from the ground and a first neutral point having a potential between the voltages of the two or more power lines, and having one end electrically connected to the ground. A fault detector including a fault detector, each of the fault detectors including a current detector for limiting a leakage current flowing to the ground to a predetermined dangerous current or less and detecting the leakage current, and among one or more fault detectors, a fault detector electrically connected to a power line is configured so that the current flowing through the fault detector flows in one direction of outflow or inflow from the ground, and includes a one-way current unit that restricts the current path in one direction so that the current flowing through the fault detector is cut off in a normal state, The detector is an electric shock and fire prevention device that detects leakage current by forming a current path for leakage current flowing from two or more power lines or a first neutral point to the ground.

In this way, most electric shock accidents and fire accidents occur between ground and power, and in order to block this, a method of supplying power by separating power and ground is adopted.

However, in this case, that is, even if the power source and the ground are insulated, if the dielectric strength between the power source and the ground is lowered, there is a risk of fire or electric shock due to the same phenomenon, that is, leakage current.

In addition, Patent Document 1 has a problem in that when a plurality of outlets are commonly connected to a ground-insulated power source, it is not easy to specify an outlet of a load having an insulation problem and the entire load must be checked.

On the other hand, among electrical devices, there is electrical equipment in which the neutral wire should not be connected to the ground due to problems such as insulation or safety.

In this insulated electric device, a ground terminal is configured separately from the power line supplied from the power facility, and the ground terminal is floated from the power line. Electric shock and fire can be prevented, but there is no prevention technology for them.

In particular, there is a problem in that the insulation state of the electric device cannot be determined because the floating ground and power line cannot be monitored.

Patent Document 1: Korean Patent Registration No. 10-2386390 Patent Document 2: Korean Patent Publication No. 10-2003-0010582 Patent Document 3: Korean Patent Publication No. 10-2019-0122444 Patent Document 4: Korean Patent Registration No. 10-2169232

The present invention has been made to solve the problems of the prior art as described above, and when a plurality of outlets are connected to a ground-separated power source, ground insulation is destroyed by diagnosing the insulation state between the ground and power source of the load connected to each outlet for each outlet. Its object is to provide an electrical device and method for measuring the leakage state of a load connected to a plurality of outlets branched off from a ground-insulated power source so as to quickly respond to the risk of electric shock or fire due to

On the other hand, if the insulation state of the load connected to each outlet can be grasped from the individual outlet, the time for easily finding and correcting the fault location is shortened, thereby reducing cost and financial resources.

을 적용하여 측정저항(432, 435)을 흐르는 제1누설전류(IR.LK) 및 측정된 전류(452)와 기준신호 발생기(453)로부터 수학식 2인

를 적용하여 전류측정수단(420)을 흐르는 제2누설전류(ICT.LK)를 연산하고, 상기 제1누설전류(IR.LK)와 상기 제2누설전류(ICT.LK)의 차를 연산하여 차분전류값(IDET)을 얻는 것과 상기 차분전류값(IDET)의 절대치 크기가 정해진 미소전류(△I)값과 비교하여, 미소전류(△I)보다 작으면 절연상태 양호로 판정하고, 미소전류(△I)보다 크면 절연상태 불량으로 판정하는 것을 특징으로 하는 접지 절연된 전원에서 분기된 다수의 콘센트에 연결된 부하의 누설상태를 측정하는 전기장치를 포함한다.
상기 다수의 콘센트를 사용하는 경우 접지-전원간 절연내력이 저하한 콘센트를 특정할 수 있는 것을 포함한다.In the electrical device for measuring the leakage state of a load connected to a plurality of outlets branched from a ground-insulated power source according to the present invention for solving the above object, it includes an individual leakage measuring device 400, and individual leakage measurement The device 400 includes an iron core type, ferrite type or HCT type current measuring means 420 which is commonly applied to two power lines and measures the current difference flowing in the two power lines; Voltage measuring means 430 for measuring each voltage; Inspection switches 431 and 434 which alternately operate each voltage measuring means at a time difference and have an operating time of one cycle or more; Insulation amplifiers (433, 436) for measuring the voltage from the measurement resistance (432, 435); An operational amplifier 421 that is directly connected to the current measuring means 420, converts the current into a voltage, and sends an output to the microprocessor 450 that determines the insulation state between ground and power supply of the load; A microprocessor 450 that converts the outputs of the operational amplifier 421 and the insulating amplifiers 433 and 436 into ADC (Analog-Digital Converter) and determines the insulation state between ground and power supply of the connected load through internal operation; and a display processing unit 460 that notifies the result of the insulation state to the outside, and the microprocessor 450 receives Equation 1 from the measured voltage 451 and the reference signal generator 453.

By applying Equation 2 from the first leakage current (IR.LK) flowing through the measurement resistors (432, 435) and the measured current (452) and the reference signal generator (453)

The second leakage current (ICT.LK) flowing through the current measuring means 420 is calculated by applying , and the difference between the first leakage current (IR.LK) and the second leakage current (ICT.LK) is calculated. Obtaining the differential current value (IDET) and comparing the absolute value of the differential current value (IDET) with the determined minute current (ΔI) value, if smaller than the minute current (ΔI), it is determined that the insulation state is good, and the minute current An electric device for measuring a leakage state of a load connected to a plurality of outlets branched from a grounded insulated power source, characterized in that the insulation state is determined to be defective if it is greater than (ΔI).
In the case of using the plurality of outlets, it is possible to specify an outlet whose dielectric strength between the ground and the power source is reduced.

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을 적용하여 측정저항(432, 435)을 흐르는 제1누설전류(IR.LK)를 연산하는 연산단계(454); b) 측정된 전류(452)와 기준신호 발생기(453)로부터 수학식 2인

를 적용하여 전류검출기(420)를 흐르는 제2누설전류(ICT.LK)를 연산하는 연산단계(455); c) 상기 연산된 상기 제1누설전류(IR.LK)와 상기 제2누설전류(ICT.LK)의 차를 연산하여 차분전류값(IDET)을 얻는 단계(456); d) 상기 차분전류값(IDET)의 절대치 크기가 정해진 미소전류(△I)값과 비교하여, 미소전류(△I)보다 작으면 절연상태 양호로 판정하고, 미소전류(△I)보다 크면 절연상태 불량으로 판정하는 단계(458, 459); e) 상기 절연상태의 결과를 외부에 알리는 표시처리단계(460);를 포함한다.In addition, as a method of measuring the leakage state of a load connected to a plurality of outlets branched from a ground-insulated power source, a) Equation 1 from the measured voltage 451 and the reference signal generator 453

a calculation step 454 of calculating a first leakage current IR.LK flowing through the measurement resistors 432 and 435 by applying ?; b) Equation 2 from the measured current 452 and the reference signal generator 453

a calculation step (455) of calculating a second leakage current (ICT.LK) flowing through the current detector 420 by applying ?; c) obtaining a differential current value (IDET) by calculating a difference between the calculated first leakage current (IR.LK) and the second leakage current (ICT.LK) (456); d) Compared with the minute current (ΔI) value where the absolute value of the differential current value (IDET) is determined, if it is smaller than the minute current (ΔI), the insulation state is judged to be good, and if it is greater than the minute current (ΔI), insulation is determined. determining that the state is bad (458, 459); e) a display processing step 460 of notifying the result of the insulation state to the outside;

과 상기 수학식 2인

의 연산을 위한 측정시간은 한 주기 이상이며 상기 주기의 정수배인 것을 특징으로 한다.1 person

And the above equation 2 people

The measurement time for the operation of is more than one period and is characterized in that it is an integer multiple of the period.

The value of the minute current (ΔI), which is the insulation criterion, is changeable according to the capacity of the system or the application environment and is characterized in that it has a value of 50 mA or less. Here, 50mA is the limit capacity of a typical earth leakage breaker, and the maximum value is presented for both home and industrial use. When applied to actual household and industrial applications, it can be commercialized by dividing into 30mA and 50mA.

An electric device and method for measuring the leakage state of loads connected to a plurality of outlets branched from a ground-insulated power source according to the present invention measures the leakage state of individual outlet loads when a plurality of outlets are used to measure the dielectric strength between ground and power supply Since this degraded outlet can be specified, it has the effect of reducing expenses and fixing time.

In addition, it is possible to disconnect individual outlets without shutting off the entire power supply, thereby maintaining the operation time of the facility, thereby obtaining economic effects.

In addition, since a method for easily tracking the location of insulation deterioration between ground and power supply is provided, large-scale accidents such as fire or personal injury can be prevented in advance.

1 is a load (500, ....., branched from a ground-insulated power system 200 to a plurality of outlets (300, ....., 300-N) according to an embodiment of the present invention. 500-N) state diagram.
2 is a diagram showing the internal configuration of individual leakage measuring devices 400, ....., 400-N proposed in the present invention.
3 to 10 are state diagrams showing the flow of leakage current connected to an outlet according to the operation of the inspection switches 431 and 434 of the individual leakage measuring device of the present invention.
11 is a microprocessor operation flow chart in the individual leakage measuring device of the present invention.

Since the present invention can be practiced by applying various changes, specific embodiments are illustrated in the drawings and will be described through detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

Like reference numerals have been used for like elements throughout the description of each figure. In describing the present invention, if it is determined that a detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted.

In the present invention, when a plurality of outlets are connected to a ground-insulated power source to receive power, the insulation deterioration state of the electrical device is measured at the connected individual outlets, so that the location of the electrical device with insulation deterioration can be found as easily as possible, so that a breakdown can be solved. We can suggest ways to save time and effort.

1 is a schematic representation of power and loads to which the present invention is applied, and the system power supply 100 includes an isolation transformer 200 for ground insulation and individual outlets 300, 300-1, ....., 300-N Power is supplied to each load (500, 500-1, ....., 500-N) through. At this time, the insulation state of each load (500, 500-1, ....., 500-N) is measured for each outlet (300, 300-1, ....., 300-N) and the insulation state is determined Shows the individual leak measuring devices (400, 400-1, ....., 400-N) to be used. For example, if the ground insulation state of the load 500 deteriorates, the individual leakage measuring device 400 determines this and informs the outside through means such as a built-in display device or communication device so that action can be taken.

Figure 2 describes a single-phase input as an example of the internal circuit of the individual leakage measuring device 400 presented in the present invention, but this is applicable to three-phase as the same principle. The two power sources including the ground input to the input terminal 410 pass through the current detector 420 for measuring the current flowing in the two power sources excluding the ground and the voltage detector 430 drawn from each of the two power lines, and then the output terminal 440 ) is connected to The current detector 420 is used to measure the difference in current flowing through the two wires, and the measured current is converted into a voltage through the operational amplifier 421 and converted into an ADC (Analog-Digital Converter) built in the microprocessor 450. In addition, the two voltages input from the voltage detector 430 are connected to the ground through the respective check switches 431 and 434 and the measuring resistors 432 and 435. It is distributed to and converted to ADC (Analog-Digital Converter) built in the microprocessor 430 through the insulation amplifiers 433 and 436. Here, the measurement resistances 432 and 435 are set to sufficiently large values safe from electric shock. If an abnormality occurs in the ground insulation in the load connected to the output terminal 440, it is notified through a buzzer, a warning light, communication, etc. through the output unit 460 so that measures are taken. In this case, power line communication, wired/wireless communication, and the like can be arbitrarily selected.

3 is a conceptual diagram showing the operation form of the individual leak detector 400 presented in FIG. 2. Although the position of the load is slightly changed for convenience, there is no difference in the operation configuration of the circuit because it is connected to the same power line. The individual leak detector 400 is indicated by a dotted line, and the inspection switches 431 and 434 intermittently operate to connect each power line to the measurement resistances 432 and 435. At this time, the inspection switch 431 and the inspection switch 434 are not operated simultaneously and are operated alternately. If, as shown in FIG. 3, if the power-to-ground resistance does not appear on the output side of the outlet 300 including the load 500, the current to the measurement resistance 432 does not flow through the check switch 431 and the resistance of the measurement resistance 432 The measured voltage will be '0'. In addition, since there is no current flowing through the current sensor 420, the output voltage of the operational amplifier (421) measuring the current value will also be '0'.

4 is a diagram showing the case where the operation of the inspection switch 431-1 of the outlet 420-1 in which the individual leakage measuring device is installed among the plurality of outlets overlaps, and the inspection switch 431 of the individual leakage measuring device 400 and The case where the inspection switch (431-1) of the individual leakage measuring device (400-1) is operated at the same time is shown, but also at this time, no current flows, so no voltage appears in the measuring resistance (432) and the voltage is also in the operational amplifier (421). not measured At this time, if the inspection switch 431 of the individual leakage measuring device 400 and the inspection switch 434-1 of the individual leakage measuring device 400-1 operate, a voltage other than '0' is detected in the measuring resistance 432. The current is also detected by the current detector, and since the phenomenon at this time is the same as that of FIG. 7, it is included in the description of FIG.

5 is a case where resistance or impedance 600, which appears as insulation breakdown, appears at the output terminal of the individual leakage measuring device 400, that is, when the ground insulation is deteriorated, and when the inspection switch 431 operates, it is checked from the power source 200. The switch 431, the measurement resistor 432, the ground, the resistance or impedance 600 resulting from insulation breakdown, and the leakage current path 601 to the power source flow, and a voltage can be obtained from the measurement resistor 432. Since the resistance value of the measurement resistor 432 is already known, the first leakage current IR.LK, which is an average value of one cycle of the current flowing through the leakage current path 601, can be calculated from the measured voltage using Equation 1. For convenience, constant terms such as (2π) are not included.

검출된 전압의 한주기 평균치인 제1누설전류 here,

The first leakage current, which is the average value of one cycle of the detected voltage

전원과 동위상의 정규화된 정현파

Normalized sine wave in phase with power supply

저항(R11) 양단의 전압

Voltage across resistor (R11)

In addition, the second leakage current ICT.LK, which is an average value of one period of the current detected by the current detector 420, can be obtained from Equation 2.

검출된 전류의 한주기 평균치인 제2누설전류 here,

The second leakage current, which is the average value of one cycle of the detected current

전원과 동위상의 정규화된 정현파

Normalized sine wave in phase with power supply

전류검출기(420)에서 검출된 전류

Current detected by current detector 420

In addition, the leakage state of the load connected to the specific outlet 300 and the individual leakage measuring device 400 can be determined by Equation 3.

If the differential current value (IDET) value is 0, the insulation of the load connected to the given outlet 300 is in a good state. It is judged that the insulation resistance between the lines appears. However, since insulation resistance tends to appear in all electric devices even in normal cases, it is necessary to set some range for determining the leakage state, which needs to be set in an adjustable form.

Applying the determination method of Equation 3 in Equation 1 to FIG. 5,

IR.LK > 0

Since ICT.LK = 0

IDET = IR.LK - ICT.LK > 0 can be obtained and the connected load can determine that the insulation between ground and power line is not good.

6 is a diagram representing the flow of leakage current when a plurality of individual leakage measuring devices to which the present invention is applied are connected in parallel to the same power source 200 and the inspection switches 431 and 431-1 are operated simultaneously, which appears as insulation breakdown. The leakage current flowing through the resistance or impedance 600 has two paths 601 and 602. First, a first leakage current IR.LK obtained through the leakage current path 601 and a second leakage current ICT.LK obtained through the current detector 420 can be obtained, and the results are as follows. in other words,

IR.LK > 0

Since ICT.LK = ICT.LK(601) + ICT.LK(602) < 0 (considering the direction of the current),

IDET = IR.LK - ICT.LK > 0 can be obtained and the connected load can determine that the insulation between ground and power line is not good. At this time, it should be noted that the ICT.LK 602 calculated for the current flowing through the leakage current path 602 has a negative value, which is evident from Equation 2.

7 is a leakage current path when the inspection switch 431 of the individual leakage measuring device 400 is operated when the insulation state between the ground and power supply of the load of the outlet 300-1 is deteriorated in the same connection environment as FIG. , the leakage current flows along the current path 603, and the first leakage current (IR.LK) and the second leakage current (ICT.LK) measured at that time are as follows.

IR.LK > 0

Since ICT.LK = IR.LK > 0

IDET = IR.LK - ICT.LK = 0 can be obtained, and the load connected to the individual leakage measuring device 400 can determine that the ground-power insulation is in a good state.

8 is an individual leakage test switch 431 adjacent to the inspection switch 431 of the individual leakage measuring device 400, in which the insulation resistance between the ground and the power source exists at the load end of the outlet 420-1 where the individual leakage measuring device is installed among the plurality of outlets. When the inspection switch 431-1 of the measuring device 400-1 operates simultaneously, it has two leakage currents 603 and 604 as a leakage current flow chart. At this time, the first leakage current path appearing in the individual leakage measuring device 400 The current value by 603 is as follows.

IR.LK > 0

Since ICT.LK = IR.LK > 0

IDET = IR.LK - ICT.LK = 0. In addition, the second leakage current path 604 does not affect the individual leakage measuring device 400, so it is not reflected in the calculation. As a result, since the differential current value (IDET) at the load to which the individual leakage measuring device 400 is connected is '0', it can be determined that the load connected to the outlet 300 has good insulation between ground and power supply.

9 is a figure showing the case where only the check switch 431 of the individual leak measuring device 400 operates as a case where there is insulation resistance between ground and power supply in two or more outlets 300 and 300-1, and two leaks The first leakage current IR.LK and the second leakage current ICT.LK measured by the individual leakage measuring device 400 showing the current paths 601 and 602 can be obtained as follows.

IR.LK = IR.LK(601) + IR.LK(603) > 0

Since ICT.LK = IR.LK(603) > 0

IDET = IR.LK - ICT.LK = IR.LK(601) > 0. From the determination formula, it is shown that the load connected to the outlet 300 has an insulation resistance between the ground and the power supply, and repair or action is required. It is known that the insulation between ground and power of the load connected to the other outlet (300-1) is bad, but the exact location cannot be specified, and this is due to the individual leakage measuring device (400-1) connected to the other outlet (300-1). This is something that needs to be checked through

10 is an inspection switch of an individual leakage measuring device (400, 400-1) connected to each outlet (300, 300-1) in which insulation resistance exists between ground and power supply in two or more outlets (300, 300-1) (431, 431-1) shows the case of operating at the same time, there is a total of four resistances or impedances (600-1, 600-2, 600-3, 600-4) that appear as insulation breakdown, and one leakage path ( 604) can be ignored because it has no effect on the measurement of the individual leak measuring device 400. First, when the inspection switch 431 of the individual leakage measuring device 400 is operated, the first leakage current IR.LK detected through the voltage detector 430 is the current through the two leakage current paths 601 and 603 is measured, and the second leakage current (ICT.LK) measured through the current detector 420 is measured as current through a total of three leakage current paths 601, 602, and 603. At this time, since the currents through the leakage current path 601 cancel each other out in the current detector 420, the current measured in the current detector 420 is the leakage current through the leakage paths 602 and 603, and the measurement results are as follows. same.

IR.LK = IR.LK(601) + IR.LK(603) > 0

Since ICT.LK = ICT.LK(602) + ICT.LK(603)

IDET = IR.LK - ICT.LK

= IR.LK(601) + IR.LK(603) - ICT.LK(602) - ICT.LK(603)

Here, since IR.LK(603) = ICT.LK(603), if these two items are offset, the differential current value (IDET) is as follows.

IDET = IR.LK(601) - ICT.LK(602)

As can be seen in the figure, since ICT.LK (602) has a negative value, as a result, IDER has a positive value other than '0', and the load connected to the outlet 300 is insulated between ground and power. It can be determined that there is something wrong.

11 shows a flow chart in which the results obtained from the above series of logical matters are programmed in the microprocessor 450 in the individual leakage measuring device 400, and the current obtained from the current detector 420 and the voltage detector 430 And the output of the insulation amplifiers (433, 436) is converted to ADC (Analog-Digital Converter) in the microprocessor (450) to obtain a voltage measurement value (451), and the output of the operational amplifier (420) is also ADC converted to measure the current A value is obtained (452), a standardized reference signal is generated in phase synchronization with the power supply (453), the obtained voltage measurement value and the reference signal are periodically divided and averaged according to Equation 1 (454), and the obtained current is measured The value and the reference signal are periodically divided and averaged according to Equation 2 (455), and the result of the two equations is calculated according to Equation 3 to obtain a differential current value (IDET) (456), and the obtained differential current value (IDET) If the absolute value of is less than the set microcurrent (ΔI), it is determined that the insulation state is good (458). (459), and a display unit processing function (461) for informing the outside of the judgment result through means such as sound, light, and communication.

Although the present invention describes its configuration and operation method for single-phase, it can be easily understood that it can be applied to the same operation method for three-phase. That is, the present invention is a proposal that can be generally used for single-phase, three-phase and higher constants, and applying a multi-phase system does not deviate from the scope of the present invention.

100: grid power
200: isolation transformer
300, 300-1, 300-N: Outlet
400, 400-1, 400-N: Individual leakage measuring device
500, 500-1, 500-N: load connected to each outlet
600, 600-1: Resistance or impedance resulting from insulation breakdown
410: input terminal of the device
420: current detector
430: voltage detector
440: output terminal of the device
450: microprocessor
460: output unit
421: operational amplifier
431, 431-1, 434: inspection switch
432, 432-1, 435: measurement resistance
433, 436: insulation amplifier
451: ADC converted voltage measurement value
452: ADC converted current measurement value
453: regulated sinusoidal reference signal generator synchronized with power supply
454: Equation 1 application block
455: Equation 2 application block
456: Equation 3 application block
457: differential current value (IDET) determination
458: Insulation good path
459: Bad insulation path
461: insulation state result processing block
601, 602, 603, 604: leakage current path

Claims (7)

An electrical device for measuring the leakage state of a load connected to a plurality of branched outlets from a ground-insulated power source, including an individual leakage measuring device (400),
The individual leakage measuring device 400 includes an iron core type, ferrite type, or HCT type current measuring means 420 which is commonly applied to two power lines and measures a current difference flowing in the two power lines;
Voltage measuring means 430 for measuring each voltage;
Inspection switches 431 and 434 which alternately operate each voltage measuring means at a time difference and have an operating time of one cycle or more;
Insulation amplifiers (433, 436) for measuring the voltage from the measurement resistance (432, 435);
An operational amplifier 421 that is directly connected to the current measuring means 420, converts the current into a voltage, and sends an output to the microprocessor 450 that determines the insulation state between ground and power supply of the load;
A microprocessor 450 that converts the outputs of the operational amplifier 421 and the insulating amplifiers 433 and 436 into ADC (Analog-Digital Converter) and determines the insulation state between the ground and power supply of the connected load through internal operation;
It includes; a display processing unit 460 for informing the outside of the result of the insulation state,
The microprocessor 450 calculates Equation 1 from the measured voltage 451 and the reference signal generator 453.

By applying Equation 2 from the first leakage current (IR.LK) flowing through the measurement resistors (432, 435) and the measured current (452) and the reference signal generator (453)

The second leakage current (ICT.LK) flowing through the current detector 420 is calculated by applying , and the difference between the first leakage current (IR.LK) and the second leakage current (ICT.LK) is calculated to calculate the difference. Obtaining the current value (IDET) and comparing the absolute value of the difference current value (IDET) with the determined minute current (ΔI) value, if smaller than the minute current (ΔI), it is determined that the insulation state is good, and the minute current ( An electric device for measuring the leakage state of a load connected to a plurality of outlets branched from a grounded insulated power source, characterized in that if it is greater than ΔI), it is determined that the insulation state is defective. delete delete According to claim 1,
When using the plurality of outlets, the electrical device for measuring the leakage state of the load connected to the plurality of outlets branched from the ground-insulated power source, characterized in that it is possible to specify the outlet with reduced dielectric strength between the ground-power source. a) Equation 1 from the measured voltage 451 and the reference signal generator 453

a calculation step 454 of calculating a first leakage current IR.LK flowing through the measurement resistors 432 and 435 by applying ?;
b) Equation 2 from the measured current 452 and the reference signal generator 453

a calculation step (455) of calculating a second leakage current (ICT.LK) flowing through the current detector 420 by applying ?;
c) obtaining a differential current value (IDET) by calculating a difference between the calculated first leakage current (IR.LK) and the second leakage current (ICT.LK) (456);
d) Compared with the minute current (ΔI) value where the absolute value of the differential current value (IDET) is determined, if it is smaller than the minute current (ΔI), the insulation state is judged to be good, and if it is greater than the minute current (ΔI), insulation is determined. determining that the state is bad (458, 459);
e) a display processing step (460) of notifying the result of the insulation state to the outside. According to claim 5,
1 person

And the above equation 2 people

The measurement time for the operation of is more than one cycle and is an integer multiple of the cycle. According to claim 5,
The microcurrent (ΔI) value, which is the insulation criterion, is variable according to the capacity or application environment of the system and has a value of 50 mA or less. How to measure health.

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