TWI696838B - Insulation measuring apparatus and insulation measuring method - Google Patents

Abstract

The invention provides an insulation measurement device and an insulation measurement method, which can surely remove the error factor during detection and accurately obtain the true resistance component leakage current with good accuracy. The insulation measuring device (10A) measures the leakage current of the resistance component of the three-phase wiring TRS connected to the three-phase motor (2) from the power source (1). The system is equipped with: each bus bar (11), which is respectively connected to the three-phase wiring TRS; ZCT (12), which has a through hole (12a), fixedly supporting each bus bar (11) in an insulated manner and making each The bus bar (11) penetrates the through hole (12a), and detects the zero-phase current synthesized by the through currents flowing through the bus bars (11); CT (13), which detects at least one bus bar (11) ) Through current; and the control part (14), which uses at least one through current detected in CT (13) to correct the detected zero-phase current and measure the resistance component leakage current.

Description

Insulation measurement device and insulation measurement method

The present invention relates to an insulation measurement device and an insulation measurement method, which measure the leakage current of a resistance component of a three-phase wiring connected from a power source to a three-phase motor.

For example, in the wiring to the motor, leakage current is generated due to deterioration of the insulation resistance of the inductor, and a zero-phase-sequence current transformer (ZCT) is widely used as a detection sensor .

The zero-phase current transformer (ZCT) detects the zero-phase current synthesized by the through currents of the three phases by passing the AC three-phase wires together through the current transformer.

Here, since the zero-phase current transformer (ZCT) uses the through current as the primary winding and the coil inside the zero-phase current transformer (ZCT) is used as the secondary winding transformer, the current corresponding to the winding ratio is output to the zero-phase Current secondary (ZCT) secondary side. Therefore, if the three-phase through currents are passed through the zero-phase current transformer (ZCT) together, the zero-phase current combined with the three-phase through currents flows to the secondary side. At this time, since the three-phase AC has the same magnitude in each phase and each has a phase difference of 120°, the zero-phase current synthesized by the through currents of the three phases of the three-phase AC is zero. In other words, in a normal state, no current flows on the secondary side of the ZCT.

On the other hand, the zero-phase current flowing on the secondary side of the zero-phase current transformer (ZCT) refers to the state when the balance of the three-phase current is broken, that is, the current flows from one of the three-phase wires to the ground, In other words, it is when the leakage current occurs. As a result, by using a zero-phase current transformer (ZCT), it can be detected which of the three-phase phase wiring is below a predetermined insulation resistance.

For such a technique, for example, the ground voltage sensitivity test method disclosed in Patent Document 1 may be mentioned.

In the ground voltage sensitivity test method disclosed in Patent Document 1, the ground voltage sensitivity test device 100 used in it is shown in FIG. 9 and includes a zero-phase current transformer 101, a ground direction relay 102, and a voltage measurement unit 103. Transformer T, residual voltage eliminating device 104, power supply 105, measurement tester 106, and voltage detector 107.

In this ground voltage sensitivity test method, the voltage measuring section 103 measures the residual current voltage, that is, the leakage voltage, and when the residual current voltage is generated, the residual voltage eliminating device 104 is connected to the power supply 105, and the residual voltage eliminating device 104 The output terminals y1 and y2 are connected to the output terminals y1 and y2 of the voltage measuring unit 103, the phase is adjusted using the phase adjuster 104a, and the voltage is adjusted using the voltage adjuster 104b so that the residual current voltage appearing in the voltage detector 107 becomes zero .

Thereby, since the residual voltage of the voltage measurement unit 103 is removed, it is possible to measure the correct ground voltage that is not affected by the residual voltage.

[Prior Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 4-48273 (published on September 8, 1998)

[Patent Document 2] Japanese Published Patent Gazette "Japanese Patent Laid-Open No. 2010-25743 (published on February 4, 2010)"

However, in the ground voltage sensitivity test method disclosed in the conventional patent document 1, the residual current is corrected by making the value of the zero-phase current containing the residual current zero to the premise that the motor is not deteriorated ( The residual current voltage in Patent Document 1). However, even when the motor is only slightly degraded in the initial state, the state contains the initial error. In addition, if the penetration position and the penetration current of the current collector 101 change from zero toward the distribution line, the phase and magnitude of the correction value change, and there is a problem that correction needs to be made again.

These issues will be described in detail below.

In other words, the leakage current (Io) includes two components: a capacitance component leakage current (Ioc) that can flow normally and a resistance component leakage current (Ior) that causes fire and accidents. The resistance component leakage current (Ior) gradually rises with the deterioration of the insulation, and when it falls below a predetermined insulation resistance, the insulation is broken and the motor is broken. For this measurement of the resistance component leakage current (Ior), a method of separating two components is widely used, which is called an Ior method.

In the Ior method, as shown in FIG. 10, the insulation resistance, that is, the voltage applied to the three-phase wiring is measured in the voltage acquisition unit (S101). Next, the zero-phase current is measured in the zero-phase current transformer (ZCT) (S102). After that, the zero-phase current is separated into a capacitance component leakage current (Ioc) and a resistance component leakage current (Ior) (S103). Finally, the insulation resistance value is calculated from the resistance component leakage current (Ior) and the voltage (S104).

Here, in order to let the user know the deterioration of the insulation as early as possible, it is necessary to measure a small resistance component leakage current (Ior) flowing, for example, with an insulation resistance of about 10 MΩ. In the case of a 200V motor, the resistance component leakage current (Ior) corresponding to 10 MΩ is about 20 μA. In addition, as described above, the zero-phase current transformer (ZCT) uses the through current of the three-phase wiring as the primary winding and the coil inside the zero-phase current transformer (ZCT) as the secondary winding transformer. The current of the ratio is output to the secondary side of the ZCT (ZCT). Since the zero-phase current output to the secondary side of the zero-phase current transformer (ZCT) is usually about 1/1000, it is necessary to have nA-level measurement accuracy. As a result, the zero-phase current output to the secondary side of the zero-phase current transformer (ZCT) is also affected by the induced noise in the surrounding environment. And the current measurement circuit needs sufficient metal shielding.

In addition, the drive current of the motor differs according to the capacity of the motor, and in the case of a 300 kW high-capacity product of a general low-voltage motor, it flows about 600 A. Therefore, because it is a very strict measurement system capable of measuring a primary current of 600A to a secondary current of nA level, it is necessary to take measures to eliminate surrounding noise.

Moreover, not only the surrounding noise, but also the measurement accuracy of the zero-phase current transformer (ZCT) becomes a problem. When the zero-phase current transformer (ZCT) measures the zero-phase current on the secondary side, an error current called residual current is generated. This is called the residual current error current, which is due to the structural non-uniformity such as the manufacturing unevenness of the iron core constituting the zero-phase current transformer (ZCT) or the winding unevenness of the coil, which cannot be accurately masked Cut off the magnetic flux generated by the through current. Because the zero-phase current transformer (ZCT) measures the leakage current of the three-phase wiring, that is, the unbalanced component of the three-phase wiring, the unbalanced component of the structural unevenness becomes an error. In terms of this structural non-uniformity, for example, because of the magnitude and phase of the residual current The difference may change according to the positional relationship between the three-phase wiring and the zero-phase current transformer (ZCT), so it is difficult to identify the error factor.

The residual current including the error for the resistance component leakage current (Ior) when the insulation resistance required for the original measurement is 10 MΩ is very large, so it is impossible to measure the small resistance component leakage current (Ior), and because the insulation is sufficiently deteriorated After that, it becomes measurable beyond 10MΩ. If the insulation is sufficiently deteriorated, the time until the insulation is broken becomes insufficient, and the user must perform urgent repairs without being able to maintain it in a planned manner.

As described above, since the residual current includes an error due to non-uniformity in the structure of the zero-phase current transformer (ZCT), the magnitude and phase of the residual current vary depending on the penetration position of the three-phase wiring. In addition, there is a problem that the current of the motor driven by the capacity of the motor changes, and the magnitude of the residual current also changes according to the magnitude of the current.

In addition, as a conventional technique that uses the Ior method that separates the two components of the capacitance component leakage current (Ioc) and the resistance component leakage current (Ior), for example, the insulation measurement device disclosed in Patent Document 2 is conventional Known. However, even in the insulation measurement device disclosed in Patent Document 2, it is impossible to analyze the residual current including such various errors.

An aspect of the present disclosure is accomplished in view of the conventional problems, and its object is to provide an insulation measurement device and an insulation measurement method. The aforementioned insulation measurement device and insulation measurement method can reliably remove the error factor during detection. And the leakage current of the real resistance component is obtained with good accuracy.

The inventors found out the phase of the residual current by investigating the generation factor of the residual current (current based on error) of the three-phase motor and fixing the penetration position of the zero-phase current transformer and the three-phase wiring toward the three-phase motor using conductive members If there is no change in the size, the insulation measurement device and the insulation measurement method of the present disclosure are completed.

One specific aspect of the insulation measurement device and insulation measurement method of the present disclosure is as follows.

In order to solve the above-mentioned problems, the disclosed insulation measurement device measures the leakage current of the resistance component of the three-phase wiring connected from the power supply to the three-phase motor, which includes: each conductive component, which is connected to the three-phase Wiring; a zero-phase current transformer, which has through-holes, fixedly supports each of the conductive members in an insulated manner and allows each of the conductive members to pass through the through-holes, and detects each of the through-currents that will flow through each of the conductive members Synthesized zero-phase current; a penetrating current comparator, which detects penetrating current flowing through at least one of the conductive members; and a control unit, which uses at least one penetrating current detected by the penetrating current comparator, to Correct the detected zero-phase current and measure the resistance component leakage current.

In order to solve the above-mentioned problems, the present invention discloses an aspect of the insulation measurement method, which measures the leakage current of the resistance component of the three-phase wiring connected from the power supply to the three-phase motor. Each conductive member of the wiring; a zero-phase current detection step, which is a zero-phase current transformer, which supports and supports each of the conductive members in an insulated manner and allows each of the conductive members to pass through the through holes, and detects that each of the conductive members will flow The zero-phase current synthesized by the penetrating currents of the components; the penetrating current detection step, which is a penetrating current ratio detector, which detects the penetrating current flowing through at least one of the conductive members; and the measuring step, which is used at the penetrating current ratio At least One of the aforementioned through currents corrects the detected zero-phase current and measures the leakage current of the resistance component.

According to one aspect of the present disclosure, the following effect can be produced: an insulation measurement device and an insulation measurement method can be provided. The insulation measurement device and the insulation measurement method can surely remove the error factor during detection, and can accurately find the true Leakage current of the resistance component.

1: power supply

2: three-phase motor

3: three-phase motor

10A, 10B: Insulation measuring device

11: busbar (conductive parts)

12: ZCT (ZCT)

12a, 13a: through hole

13: through current ratio (CT)

23a, 23b, 23c: through current comparator (CT)

14: Control Department

14a: Measurement zero-phase current acquisition section (first measurement zero-phase current acquisition section)

14b: Correction section (first correction section)

14c: Voltage acquisition unit (first voltage acquisition unit)

14d: Calculation Department (First Calculation Department)

24: Control Department

24a: Measurement zero-phase current acquisition section (second measurement zero-phase current acquisition section)

24b: Correction section (second correction section)

24c: Voltage acquisition unit (second voltage acquisition unit)

24d: Calculation Department (Second Calculation Department)

I _R1 : first residual current

I _R2 : second residual current

I _T1 : first through current

I _T2 : second through current

I _T3 : third through current

TRS: three-phase wiring

α, β: constant

γ, δ: unbalance coefficient

101: zero-phase current transformer

102: Ground direction relay

103: Voltage measurement section

104: Residual voltage elimination device

104a: phase adjuster

104b: voltage regulator

105: power supply

106: Measuring tester

107: Voltage detector

[Fig. 1] A perspective view showing the overall configuration of an insulation measurement device according to Embodiment 1 of the present disclosure.

[Fig. 2] A flowchart showing a correction method of the aforementioned insulation measurement device when it is shipped from the factory.

[Fig. 3] A diagram showing the concept of introducing a correction message for the aforementioned insulation measurement device.

FIG. 4 is a flowchart showing a correction method when the user of the insulation measurement device is used.

[Figure 5] (a) is a vector diagram of the residual current corrected from the zero-phase current measured by the aforementioned insulation measuring device to obtain the true zero-phase current; (b) is the zero-phase current without residual current correction Vector illustration.

6 is a perspective view of the overall configuration of an insulation measurement device according to Embodiment 2 of the present disclosure.

7 is a diagram showing the concept of introducing a correction message for the imbalance state of the insulation measurement device.

[FIG. 8] (a) is a graph used to calculate the correction message γ as the unbalanced state of the insulation measurement device; (b) is a graph used to calculate the correction message δ as the unbalanced state.

9 is a circuit diagram showing the structure of a conventional ground voltage sensitivity test device.

FIG. 10 is a flowchart showing a measurement flow when no correction is performed in the conventional insulation measurement device.

Hereinafter, an embodiment of one aspect of the present disclosure will be described based on the drawings (hereinafter, also referred to as "this embodiment").

(Application example)

First, based on FIG. 1, an example to which the present disclosure is applied will be described. FIG. 1 is a perspective view showing the overall configuration of an insulation measurement device 10A according to an aspect of the present disclosure.

As shown in FIG. 1, the insulation measurement device 10A of the present disclosure measures the resistance component leakage current (Ior) of the three-phase wiring TRS connected to the three-phase motor 2 from the power source 1. Next, it is equipped with: each bus bar 11.11.11, which is respectively connected to the three-phase wiring TRS; a zero-phase current transformer (ZCT) 12, which has a through hole 12a and is fixed in an insulated manner Support each bus bar 11.11.11 and make each bus bar 11.11.11 pass through the through hole 12a, and detect the zero-phase current synthesized by the through currents flowing through each bus bar 11.11.11; the through current Current transformer (CT) 13, which detects the through current flowing through at least one bus 11.11.11; and the control unit 14, which is used for at least one penetration detected by the current transformer (CT) 13 Current to correct the detected zero-phase current and measure the resistance component leakage current (Ior).

Moreover, the insulation measurement method of the present disclosure measures the leakage current of the resistance component of the three-phase wiring connected from the power supply to the three-phase motor, which includes: a setting step, which sets each of the three-phase wiring TRS Busbar 11.11.11; Zero-phase current detection step, which is a zero-phase current transformer (ZCT) 12, which supports each busbar 11.11.11 in an insulated manner and makes each busbar 11.11. 11 The through-hole 12a is penetrated, and the zero-phase current synthesized by the through-currents flowing through each bus bar 11.11.11 is detected; the through-current detection step, which is located in the through-current comparator (CT) 13, detects the flow At least one busbar 11.11.11 through current; and the measuring step, which uses at least one through current detected by the through current ratio (CT) 13 to correct the detected zero-phase current and measure the resistance Component leakage current (Ior). In addition, the bus bar 11 has a function as a conductive member of the present disclosure.

By this, since the zero-phase current toward the power supply line of the three-phase motor 2 is directly detected, it is possible to measure the resistance component leakage current (Ior) that only shows the insulation deterioration state of the three-phase motor 2.

In addition, the bus bar 11.11.11 has conductivity, and each bus bar 11.11.11 is fixedly supported by the through hole 12a of the ZCT 12 in an insulated manner and penetrates the through hole 12a. Therefore, since the position of the power supply line of the three-phase motor 2 is fixed in the through hole 12a of the ZCT 12, the phase and magnitude of the residual current will not change. As a result, the error factor can be eliminated, and the aforementioned error factor refers to changing the magnitude and phase of the residual current according to the penetration position of each three-phase wiring TRS in the through hole 12a of the ZCT 12. Therefore, the residual current can be corrected, and the leakage current (Ior) of the tiny resistance component of nA level can be measured.

In addition, the insulation measurement device 10A according to the aspect of the present disclosure further includes a control unit 14 that uses at least one penetration current detected by the penetration current comparator (CT) 13 to correct the detected zero-phase current. , And measure the leakage current of the resistance component.

With this, since at least one penetration current detected by the penetration current transformer (CT) 13 is used to correct and measure the zero-phase current, an error factor based on the motor capacity of the three-phase motor 2 can be eliminated. In addition, since the control unit 14 measures the resistance component leakage current (Ior), it is possible to obtain the true resistance component leakage current (Ior) after correcting and measuring the zero-phase current.

Therefore, it is possible to provide an insulation measurement device 10A and an insulation measurement method which can surely remove the error factor at the time of detection and obtain the true resistance component leakage with good accuracy Leakage current (Ior). Moreover, because the insulation deterioration of the three-phase motor 2 can be found early, it can be preserved in a planned manner.

[Embodiment 1]

The embodiment of the present disclosure will be described based on FIGS. 1 to 5 as follows.

(Configuration example)

The overall configuration of the insulation measurement device 10A of this embodiment will be described based on FIG. 1. FIG. 1 is a perspective view showing the overall configuration of an insulation measuring device according to an embodiment of the present disclosure.

As shown in FIG. 1, the insulation measurement device 10A of the present embodiment measures the insulation resistance value of the three-phase wiring TRS connected from the power supply 1 to the three-phase motor 2. In addition, the power supply 1 may be a secondary side of an inverter.

The insulation measurement device 10A is equipped with: three busbars 11.11.11 as conductive members, which are respectively connected to the three-phase wiring TRS; the zero-phase current transformer 12 (hereinafter referred to as ZCT12), which is located in While having the through holes 12a, the three bus bars 11.11.11 are fixedly supported in an insulated manner so that the three bus bars 11.11.11 pass through the through holes 12a, and the measurement is included in the flow through each bus bar 11. The leakage current of the through current of 11.11; the through current comparator 13 (hereinafter referred to as CT13), which measures the size of the through current flowing through at least one of the three busbars 11.11.11.

The bus bar 11 is made of a plate-shaped metal plate, and has conductivity and rigidity. When each bus bar 11.11.11 passes through the inside of the through hole 12a of the ZCT 12, each bus bar 11.11.11 and between the through hole 12a and the bus bar 11.11.11 are insulated. Specifically, an insulating material (not shown) is installed between these, and the insulating material is used so that each bus bar 11.11.11 does not move inside the through hole 12a Fixed support. In addition, in this embodiment, although the bus bar 11 is preferably rigid, it does not necessarily need to be rigid as long as it can be fixed and supported by an insulating material.

One end of each bus bar 11.11.11 is connected to the three-phase wiring TRS toward the power supply 1, and the other end is connected to the three-phase wiring TRS toward the three-phase motor 2.

The ZCT12 series has a coil not shown in the figure, which uses the through current flowing through each bus bar 11.11.11 as the primary winding, and the coil inside the ZCT12 as the secondary winding, and functions as a transformer, and, The current according to the winding ratio is output to the control unit 14 which will be described later as the secondary side of the ZCT 12.

CT13 has a through-hole 13a in the center, and becomes a through-type current device. In the present embodiment, the through hole 13a is provided so that the through hole 13a of the CT 13 penetrates any one of the three bus bars 11.11.11. CT13 measures the current value of the penetrating current flowing in one of the three bus bars 11. In the present embodiment, although the CT 13 is provided on the side of the three-phase motor 2 of the bus bar 11, it is not limited to this, and may be provided on the side of the power source 1 of the bus bar 11.

In the insulation measurement device 10A of this embodiment, for example, a control unit 14 is provided on the upper side of the ZCT 12. The control unit 14 is provided inside a housing formed by a shielding member that shields electricity and magnetism. The reason why the shielding member constitutes the case is that by covering the control unit 14 with the shielding member, the control unit 14 can be isolated from minute noise. By this, the error of the induced noise can be reduced, and it becomes possible to measure a small current of nA level.

As shown in FIG. 1, the control unit 14 includes: a measured zero-phase current acquisition unit 14a as a first measured zero-phase current acquisition unit; a correction unit 14b as a first correction unit; and a voltage acquisition as a first voltage acquisition unit Section 14c; the calculation section 14d as the first calculation section.

The measured zero-phase current acquisition unit 14a measures the magnitude and phase of the zero-phase current from the zero-phase current detected by the ZCT 12 to obtain the measured zero-phase current. The correction unit 14b obtains a correction value of the residual current corresponding to an arbitrary through current when shipped from the factory. The correction unit 14b also calculates a current corresponding correction value corresponding to the penetration current detected in the CT 13 and uses the current corresponding correction value for the measured zero-phase current to correct the measured zero-phase current and obtain the corrected zero-phase current. This corrected zero-phase current shows close to true zero-phase current. The voltage acquisition unit 14c measures the magnitude and phase of the voltage between the phase wirings of at least one bus 11 and acquires the bus voltage as the voltage of the conductive member. The calculation part 14d is composed of a CPU, and calculates the resistance component leakage current (Ior) and the insulation resistance value by the true zero-phase current and the bus voltage. The calculation result can be stored in a storage section (not shown).

The control operation using the insulation measurement device 10A having the aforementioned configuration to determine whether there is a leakage current in the three-phase wiring TRS and the insulation resistance value of the three-phase wiring TRS is based on (a) of FIGS. 2 to 5, (b) Explain. FIG. 2 is a flowchart showing a correction method when the insulation measurement device 10A of the present embodiment is shipped from the factory. FIG. 3 is a diagram showing a concept for importing correction information. FIG. 4 is a flowchart showing a correction method when the user of the insulation measurement device 10A of this embodiment is used. FIG. 5(a) is a vector diagram in which the residual current is corrected from the zero-phase current measured by the insulation measurement device 10A to obtain the true zero-phase current. FIG. 5(b) is a vector diagram showing the zero-phase current when the residual current is not corrected.

As shown in FIGS. 2 and 3, in the insulation measurement device 10A of the present embodiment, the residual current correction value corresponding to any through current flowing through the bus voltage is obtained at the time of factory shipment. In other words, the magnitude of the through current and the magnitude of the residual current flowing through the bus bar 11‧11‧11 have the characteristics of linear change. Therefore, a residual current correction value corresponding to any through current is prepared as a correction formula in advance.

Specifically, the correction formula corresponding to the correction value of the residual current of an arbitrary penetration current can be expressed as a linear expression of the penetration current. With this, the slope and intercept of the correction formula can be obtained from the first residual current when the first penetration current flows through the bus bar 11 and the second residual current when the second penetration current flows through the bus bar 11. As a result, a residual current correction value corresponding to any through current can be obtained.

Specifically, the method of calculating the residual current correction value corresponding to any through current is as follows.

As shown in FIGS. 2 and 3, first, the first through current I _T1 flowing through the bus 11 is used to measure the magnitude and phase of the first residual current I _R1 (S1), and then the second flowing through the bus 11 is used. The through current I _T2 measures the magnitude of the second residual current I _R2 (S2). Specifically, the first through current I _{T1 is} supplied from the power supply 1 shown in FIG. 1 to the three-phase motor 2 through the three-phase wiring TRS and the bus 11.11.11, and CT13 is used to measure the first residual current I _R1 Size and phase. In addition, a second through current I _{T2 is} supplied from the power supply 1 shown in FIG. 1 to the three-phase motor 2 through the three-phase wiring TRS and the bus 11.11.11, and the magnitude of the second residual current I _R2 is measured using CT13. In the present embodiment, each bus bar 11.11.11 is not fixedly moved so as to not move inside the through hole 12a of the ZCT 12. Therefore, when the first through current I _T1 and the second through current I _T2 flow through each bus 11.11.11, the phases of the first residual current I _R1 and the second residual current I _R2 do not change and are mutually the same. Therefore, only the first residual current I _R1 or the second residual current I _R2 may be measured for the phase. Therefore, in the present embodiment, for example, only the phase of the first residual current I _R1 is measured.

From this, from the graph shown in FIG. 3, as the residual current correction value, the following relational expression (Equation 1) can be introduced, and specific constant α and constant β can be obtained.

Residual current I _R = α* through current I _T + β (Equation 1).

As a result, the residual current correction value for the actual through current, that is, the current corresponding correction value can be expressed by (Expression 2).

Residual current correction value =-(α * through current + β) ... (Equation 2).

The penetrating current of (Equation 2) is the penetrating current available to the user when actually measured. In addition, a negative sign is added to (Equation 2) because the residual current correction value =-(residual current I _R ), and the correction for the measured zero-phase current is operated on the negative sign side. These calculations are performed by the correction unit 14B.

In addition, the residual current shown in FIG. 3 shows that when the first through current I _T1 flows through the bus bar 11, the first residual current I _{R1 is} generated in response to the first through current I _T1 ; When I _T2 flows through the bus bar 11, a second residual current I _{R2 is} generated in response to the second through current I _T2 . Moreover, the magnitude of the first penetration current I _T1 is preferably the penetration current of the minimum motor capacity of the three-phase motor 2 used, and the magnitude of the second penetration current I _T2 is preferably the three-phase motor 2 used Through current of the maximum motor capacity.

As a result, as shown in FIG amended message calculating the residual current I _R in the (α, β) is kept in a storage-based portion (S3) of calculating portion 14d 2.

As shown in FIG. 4, on the other hand, when a user who purchases this insulation measurement device 10A uses it, first, the through current is obtained in CT13 (S11 ). Specifically, the third through current I _{T3 is} supplied to the three-phase motor 2 from the power supply 1 shown in FIG. 1 through the three-phase wiring TRS and the bus 11.11.11. Accordingly, the size of CT13 and measuring a third correction unit 14b of a through current I _T3. Next, the correction section 14b, is obtained from the third through-current I _T3 (Formula 1), to determine a correction value corresponding to the current, i.e. the current corresponding to the third through-I residual current correction value (S12) _T3 of.

Next, while the voltage acquisition unit 14c measures the voltage and phase between the phase wirings applied to the insulation resistance of the bus 11.11.11 (S13), the zero-phase current and phase are measured at the ZCT12 and the measured zero-phase current acquisition unit 14a (S14).

Here, as shown in (a) of FIG. 5, the measured zero-phase current includes the capacitance component leakage current (Ioc) and the resistance component leakage current (Ior) as well as the residual current error. Therefore, the residual current correction value is synthesized from the measured zero-phase current vector. With this, the true zero-phase current is obtained (S15).

Next, as shown in (a) of FIGS. 4 and 5, the true zero-phase current is separated into a capacitance component leakage current (Ioc) and a resistance component leakage current (Ior) (S16). In the case of separation, by the phase difference between the measured phase of the zero-phase current and the phase of the voltage applied to the insulation resistance, it is separated into a capacitance component leakage current (Ioc) and a resistance component leakage current (Ior).

Next, the calculation unit 14d calculates the insulation resistance value based on the resistance component leakage current (Ior) and the voltage between the phase lines applied to the insulation resistance acquired by the voltage acquisition unit 14c (S17). The insulation resistance value can be obtained by dividing the voltage applied to the insulation resistance acquired by the voltage acquisition unit 14c by the resistance component leakage current (Ior).

Also, without such correction, as shown in (b) of FIG. 5, since the resistance component leakage current (Ior) is calculated based on the measured zero-phase current, an error including residual current is calculated The leakage current of the resistance component (Ior).

In this way, the insulation measurement device 10A of the present embodiment measures the resistance component leakage current (Ior) of the three-phase motor 2 connected from the power supply 1 through the three-phase wiring TRS. It is equipped with: 11.11.11 busbars as conductive parts, which are connected to the three-phase wiring TRS; Zero-phase current transformer (ZCT) 12, which has a through hole 12a, which is fixedly supported by insulation Each bus bar 11.11.11 and Each busbar 11.11.11 penetrates the through-hole 12a, and detects the zero-phase current synthesized by the through-currents flowing through each busbar 11.11.11; the through-current comparator (CT) 13, which detects The through current flowing through at least one bus bar 11.11.11; and the control unit 14 uses at least one through current detected in CT13 to correct the detected zero-phase current and measure the resistance component leakage current ( Ior).

In addition, the insulation measurement method of this embodiment measures the resistance component leakage current (Ior) of the three-phase wiring TRS connected from the power supply 1 through the three-phase wiring TRS. It consists of: a setting step, which is to set the busbars 11.11.11 which are respectively connected to the conductive parts of the three-phase wiring TRS; a zero-phase current detection step, which is in the zero-phase current transformer (ZCT) 12, Fix and support each bus bar 11.11.11 in an insulated manner so that each bus bar 11.11.11 passes through the through hole 12a, and detect the zero synthesized by the penetrating currents that will flow through each bus bar 11.11.11 Phase current; the through current detection step, which is at the through current ratio (CT) 13, to detect the through current flowing through at least one bus 11.11.11; and the measuring step, which uses at least the one detected by CT13 A through current to correct the detected zero-phase current and measure the leakage current (Ior) of the resistance component.

By this, since the zero-phase current toward the power supply line of the three-phase motor 2 can be directly detected, it is possible to measure the resistance component leakage current (Ior) that only shows the insulation deterioration state of the three-phase motor 2.

In addition, the bus bar 11.11.11 has conductivity, and each bus bar 11.11.11 is fixedly supported by the through hole 12a of the ZCT 12 in an insulated manner and penetrates the through hole 12a. Therefore, since the position of the power supply line of the three-phase motor 2 is fixed in the through hole 12a of the ZCT 12, the phase and magnitude of the residual current will not change. As a result, the error factor can be eliminated, and the aforementioned error factor refers to changing the magnitude and phase of the residual current according to the penetration position of each three-phase wiring TRS in the through hole 12a of the ZCT 12. Therefore, the residual current can be corrected, and the leakage current (Ior) of the tiny resistance component of nA level can be measured.

In addition, the insulation measurement device 10A of this embodiment further includes a control unit 14 that corrects the detected zero-phase current using at least one penetration current detected by the CT 13 and measures the resistance component leakage current (Ior) .

By this, since at least one through current detected by CT13 is used to correct the measured zero-phase current, an error factor based on the motor capacity of the three-phase motor 2 can be eliminated. In addition, since the control unit 14 measures the resistance component leakage current (Ior), it is possible to obtain the true resistance component leakage current (Ior) after correcting and measuring the zero-phase current.

Therefore, it is possible to provide an insulation measurement device 10A and an insulation measurement method that can surely remove the error factor during detection and accurately obtain the true resistance component leakage current (Ior) with good accuracy. Moreover, because the insulation deterioration of the three-phase motor 2 can be found early, it can be preserved in a planned manner.

In addition, in the insulation measurement device 10A of this embodiment, the bus bar 11 has rigidity. Thereby, when each bus bar 11.11.11 is fixedly supported inside the through hole 12a of the ZCT 12, a simple supporting member can be used and the bus bar 11.11.11 cannot be easily moved.

In addition, in the insulation measurement device 10A of the present embodiment, the control unit 14 includes a measured zero-phase current acquisition unit 14a as the first measured zero-phase current acquisition unit, which is derived from the zero-phase current detected by the ZCT 12 The magnitude and phase of the zero-phase current are measured to obtain the measured zero-phase current; the correction section 14b as the first correction section is to obtain the residual current correction value corresponding to any through current in advance and calculate the response The current corresponding to the through current detected by CT13 corresponds to the correction value, and the current corresponding correction value is used for measuring the zero-phase current to correct the measurement of the zero-phase current and obtain the corrected zero-phase current; as the voltage acquisition part of the first voltage acquisition part 14c, which measures the magnitude and phase of the voltage between at least one phase wiring of the bus 11.11.11, and obtains the bus voltage as the voltage of the conductive member; The calculation section 14d as the first calculation section calculates the resistance component leakage current (Ior) based on the corrected zero-phase current and the bus voltage.

With this, the measured zero-phase current acquisition unit 14a measures the magnitude and phase of the zero-phase current from the zero-phase current detected by the ZCT 12, and obtains the measured zero-phase current. In addition, the correction unit 14b uses the residual current correction value corresponding to any penetration current, calculates the current corresponding correction value corresponding to the penetration current detected in the CT13, and uses the current corresponding correction value for measuring the zero-phase current to correct the measurement zero Phase current, and find the true zero-phase current as the corrected zero-phase current.

Next, the voltage acquisition unit 14c measures the magnitude and phase of the voltage between at least one phase wiring of the bus 11.11.11, and acquires the bus voltage. The calculation unit 14d calculates the resistance component leakage current (Ior) based on the true zero-phase current and the bus voltage.

As a result, specifically, it is possible to provide an insulation measurement device 10A that can surely remove the error factor at the time of detection and accurately obtain the true resistance component leakage current (Ior) with good accuracy.

In addition, in the insulation measurement device 10A of the present embodiment, the correction unit 14b obtains a residual current correction value corresponding to any through current in advance from the first residual current I _R1 and the second residual current I _R2 . The residual current I _R1 includes errors, which is based on the magnitude of the first through current I _T1 detected at CT13 when the first through current I _T1 flows through the bus bar 11.11.11; the second residual current I _R2 is Including errors, it depends on the magnitude of the second through current I _T2 detected by the CT 13 when the second through current I _T2 flows through the bus bar 11.11.11.

Specifically, since the correction formula corresponding to the correction value of the residual current of any penetration current can be expressed as a linear expression of the penetration current, the first residual current I _R1 and the second penetration when the first penetration current I _T1 flows When the current I _T2 flows, the second residual current I _R2 can obtain the slope and intercept of the correction formula. As a result, the residual current correction value corresponding to any through current can be obtained.

Therefore, since the correction formula can be used to determine the correction value of the residual current that changes according to the magnitude of the through current, it is possible to save time for the user to correct, and it is possible to provide a convenient insulation measurement device 10A.

In addition, in the insulation measurement device 10A of the present embodiment, the control unit 14 is provided inside a casing made of a shielding material that shields electricity and magnetism. Thereby, by covering the control portion 14 with a casing made of a shielding material, the control portion 14 can be isolated from minute noise. By this, the error of the induced noise can be reduced, and it becomes possible to measure a small current of nA level.

[Embodiment 2]

Based on FIGS. 6 to 8, another embodiment of the present invention will be described as follows. In addition, the configuration other than that described in the present embodiment is the same as that of the aforementioned first embodiment. In addition, for convenience of explanation, components having the same functions as those shown in the drawings in the first embodiment are given the same symbols, and their descriptions are omitted.

The insulation measurement device 10B of this embodiment includes the insulation measurement device 10A of the first embodiment, as shown in FIG. 6, and also includes the following differences: three bus bars 11.11.11 are respectively provided in the CT 23a . 23b. 23c.

The overall configuration of the insulation measurement device 10B of this embodiment will be described based on FIG. 6. FIG. 6 is a perspective view of the overall configuration of the insulation measurement device 10B of this embodiment.

As shown in FIG. 6, the insulation measurement device 10B of this embodiment has three bus bars 11.11.11 provided on the CT 23a. 23b. 23c. Also, CT 23a. 23b. The 23c system is the same as the CT13 of the first embodiment.

As shown in FIG. 6, the control unit 24 is provided with: a measured zero-phase current acquisition unit 24a as a second measured zero-phase current acquisition unit; a correction unit 24b as a second correction unit; and a voltage acquisition as a second voltage acquisition unit Section 24c; the calculation section 24d as the second calculation section.

The measured zero-phase current acquisition unit 24a measures the magnitude and phase of the zero-phase current from the zero-phase current detected by the ZCT 12 to obtain the measured zero-phase current. The correction unit 24b uses the residual current correction value corresponding to any penetrating current, and calculates the current corresponding correction value corresponding to the penetrating current flowing through each bus bar 11.11.11 detected at CT 13.13.13, and uses The current corresponding to the measured zero-phase current corresponds to a correction value to correct the measured zero-phase current and obtain the corrected zero-phase current. The voltage acquiring unit 24c measures the magnitude and phase of the voltage between the phase wirings of at least one of the bus 11.11.11, and acquires the bus voltage. The calculation part 24d calculates the resistance component leakage current (Ior) by using a true zero-phase current and at least one bus voltage.

For the control operation using the insulation measurement device 10B having the aforementioned configuration, and determining whether there is a leakage current in the three-phase wiring TRS and obtaining the insulation resistance value of the three-phase wiring TRS, based on (a) of FIGS. 7 and 8, (b) Explain. 7 is a diagram showing the concept of introducing a correction message for the unbalanced state of the insulation measurement device 10B. FIG. 8(a) is a diagram for calculating the correction message γ which is the unbalanced state of the insulation measurement device 10B. FIG. 8(b) is a diagram for calculating the correction information δ as an unbalanced state.

First, in the insulation measurement device 10B of the present embodiment, in a factory or the like, it is assumed that there is current imbalance due to deterioration of the power supply environment, and the penetration current is in each phase of the three-phase wiring TRS Change situation. That is, in general, although the penetration current systems of the three-phase wiring TRS are the same, in the three-phase motor 3 installed in a factory or the like, the penetration current systems of the three-phase wiring TRS may be different from each other. As a result, the correction value of the residual current changes according to the current imbalance of the through current in each phase.

Therefore, in the insulation measurement device 10B of this embodiment, three CTs 23a are provided. 23b. 23c, to detect the through current flowing through each bus 11‧11‧11 respectively. Next, at each CT 23a. 23b. 23c. By measuring the through current of each phase, the imbalance state of the through current can be continuously monitored. Therefore, it is possible to correct the imbalance of the matching current.

The correction method of the zero-phase current measured by the insulation measurement device 10B of this embodiment will be described below.

As shown in FIG. 7, in the insulation measurement device 10B, when correction is made at the time of factory shipment, the magnitude of the first residual current I _R1 is measured using the first penetration current I _{T1 and the} measurement is performed using the second penetration current I _T2 The magnitude of the second residual current _IR2 . Specifically, the first through current I _{T1 is} supplied to the three-phase motor 3 from the power supply 1 shown in FIG. 6 through the three-phase wiring TRS and each bus 11.11.11, and CT23a is used. 23b. Any one of 23c and the correction unit 24b measure the magnitude of the first residual current I _R1 . Further, through the three-phase wiring TRS and each bus 11.11.11, the second through current I _{T2 is} supplied from the power supply 1 shown in FIG. 6 to the three-phase motor 2, and CT 23a is used. 23b. Any one of 23c and the correction unit 24b measure the magnitude of the second residual current I _R2 .

In addition, at the time of factory shipment, since an unbalanced state does not occur, the first through current I _T1 and the second through current I _{T2 can} flow in one bus 11. As a result, this processing is the same as the processing in the aforementioned first embodiment.

With this, as shown in FIG. 3 described above, as a general residual current correction value, the following (Equation 1) shown in Embodiment 1 can be obtained.

Residual current I _R =α*Through current I _T +β……(Equation 1)

Next, by (Equation 1), and by the first through current I _T1 , the first residual current I _R1 , the second through current I _T2 and the second residual current I _R2 , specific constants α and β can be obtained . The calculation part 24d performs this calculation.

Here, because there are 3 CT 23a in total. 23b. 23c, through (Equation 1), as shown in FIG. 7, as the individual residual current correction value, that is, the current corresponding correction value, the following relational expression (Equation 3) is obtained: Residual current correction value =-(α'* Through current + β') (Equation 3).

At this time, α'and β'can be expressed as (Equation 4) and (Equation 5) as follows: α'=α*γ (unbalance coefficient)... (Equation 4); β'=β*δ (unbalance Coefficient) (Equation 5).

These unbalance coefficients γ•δ can be obtained from the unbalance coefficient γ calculation table shown in FIG. 8(a) and the unbalance coefficient δ calculation table shown in FIG. 8(b).

Specifically, the vertical axis of (a) of FIG. 8 shows whether the penetration current of the S-phase wiring is 0.7 times, 0.8 times, 0.9 times, 1.0 times, 1.1 times, 1.2 times of the R-phase wiring in the three-phase wiring TRS , Any of 1.3 times; the horizontal axis in (a) of FIG. 8 shows whether the penetrating current of the T-phase wiring is 0.7 times, 0.8 times, 0.9 times, 1.0 times of the R-phase wiring in the three-phase wiring TRS Any of 1.1 times, 1.2 times, and 1.3 times. Next, the imbalance coefficient γ is shown at the intersection of each other.

Thus, for example, when the penetration current of the S-phase wiring is 0.8 times that of the R-phase wiring and the penetration current of the T-phase wiring is 0.9 times that of the R-phase wiring, the unbalance coefficient γ is 0.9. As a result, α'=α*γ (unbalance coefficient)=0.9*α.

In addition, the vertical axis of (b) of FIG. 8 shows whether the penetration current of the S-phase wiring is 0.7 times, 0.8 times, 0.9 times, 1.0 times, 1.1 times, 1.2 times, 1.3 times of the R-phase wiring in the three-phase wiring TRS Any one of the times; the horizontal axis in (b) of FIG. 8 shows whether the through current of the T-phase wiring is 0.7 times, 0.8 times, 0.9 times, 1.0 times, 1.1 times of the R-phase wiring in the three-phase wiring TRS , 1.2 times, 1.3 times. Next, the unbalance coefficient δ is shown at the intersection of each other.

Thus, for example, when the penetration current of the S-phase wiring is 0.8 times that of the R-phase wiring and the penetration current of the T-phase wiring is 0.9 times that of the R-phase wiring, the unbalance coefficient δ is 0.9. As a result, β'=β*δ (unbalance coefficient)=0.9*β.

Therefore, by substituting these α', β'(Equation 3) and the penetration current of the R-phase wiring, the measured zero-phase current can be corrected and the true zero-phase current can be obtained.

After that, the resistance component leakage current (Ior) is obtained from the true zero-phase current, and the voltage between the phase wirings obtained by the voltage acquisition unit 14c is divided by the resistance component leakage current (Ior). In addition, the insulation resistance value of the three-phase wiring TRS can be obtained. At this time, even if the through currents flowing through the three-phase wiring TRS and the bus bars 11.11.11 are different from each other, the voltage between the wiring of each phase will hardly change. Therefore, for each phase wiring voltage, one phase wiring voltage measurement may be used.

In addition, the tables shown in (a) and (b) of FIG. 8 focus on those in which the magnitude of the current value as an unbalanced state differs in each of the three-phase wiring TRS systems and represents the unbalanced coefficient γ‧δ. However, it is necessary to correct the phase because the phases as the unbalanced state change individually. Therefore, it is better It prepares a table for obtaining the phase imbalance coefficient about the phase and calculates the residual current correction value.

In this way, three CT23a are provided in the insulation measurement device 10B of this embodiment. 23b. 23c, to separately detect the through current flowing through each bus bar 11.11.11. Accordingly, by measuring the through current of each phase in the three-phase wiring TRS, it is possible to continuously monitor the imbalance state of the through current. Therefore, it is possible to correct the imbalance of the matching current.

In addition, in the insulation measurement device 10B of this embodiment, the control unit 24 includes a measured zero-phase current acquisition unit 24a as the second measured zero-phase current acquisition unit, which is derived from the zero-phase current detected by the ZCT 12 The magnitude and phase of the zero-phase current are measured to obtain the measured zero-phase current; the correction section 24b as the second correction section uses the residual current correction value corresponding to any through current, and calculates the cause in CT 23a. 23b. The current corresponding to the through currents of 11.11.11 detected by 23c corresponds to the correction value, and the current corresponding correction value is used to measure the zero-phase current to correct the measured zero-phase current and obtain the corrected The true zero-phase current of the zero-phase current; the voltage acquisition part 24c as the second voltage acquisition part, which measures the magnitude and phase of the voltage between the phase wirings of the bus 11.11.11 and acquires the bus voltage; as the first The calculation section 24d of the second calculation section calculates the resistance component leakage current (Ior) by the true zero-phase current and the bus voltage.

As a result, when the through current in the unbalanced state flows through each bus bar 11.11.11, an insulation measurement device 10B can be specifically provided, which can surely remove the error factor at the time of detection and obtain it with good accuracy True resistance component leakage current (Ior).

As described above, the insulation measurement device according to the present disclosure measures the leakage current of the resistance component of the three-phase wiring connected to the three-phase motor from the power supply. It includes: each conductive member, which is connected to the three-phase wiring ; Zero-phase current transformer, which has a through-hole, fixed support in an insulated manner Supporting each of the conductive members, allowing each of the conductive members to pass through the through-holes, and detecting a zero-phase current synthesized by each through current flowing through each of the conductive members; a through-current comparator that detects the flow of at least one of the foregoing A through-current of the conductive member; and a control unit that corrects the detected zero-phase current using at least one of the through-currents detected by the through-current rectifier, and measures the resistance component leakage current.

The disclosed insulation measurement method measures the leakage current of the resistance component of the three-phase wiring connected from the power supply to the three-phase motor. It includes: a setting step, which is to set each conductive component that is connected to the three-phase wiring A zero-phase current detection step, which is a zero-phase current transformer, which supports and insulates each of the conductive members in an insulated manner so that each of the conductive members penetrates the through-hole, and detects each through-current that will flow through each of the conductive members The synthesized zero-phase current; the penetrating current detection step, which detects the penetrating current flowing through at least one of the aforementioned conductive parts in the penetrating current comparator; and the measurement step, which uses the detection in the penetrating current comparator At least one of the through currents to correct the detected zero-phase current and measure the resistance component leakage current.

All along, in general, if the zero-phase current is used to detect the zero-phase current of the three-phase wiring, the residual current as an error will be a problem. Therefore, the user measures the zero-phase current of the ground wire and compares the measured zero-phase current. The current is separated into a capacitance component leakage current (Ioc) and a resistance component leakage current (Ior) to measure the resistance component leakage current (Ior). However, since only the leakage current (Io) flows in the ground line and a large current does not flow, the influence of the residual current as an error will not be a problem. On the other hand, the measurement of the zero-phase current on the system ground wire refers to the measurement of the leakage current of multiple loads including the motor and other loads connected to the system, so it is impossible to monitor the insulation degradation state of the load of one motor.

Therefore, in the insulation measurement device according to the aspect of the present disclosure, each conductive member is provided, which is connected to the three-phase wiring, respectively. Next, each conductive member is fixedly supported in an insulated manner so that each conductive member passes through the through hole of the zero-phase current transformer, and the zero-phase current synthesized by each through current flowing through each conductive member is detected using the zero-phase current transformer . As a result, in one aspect of the present disclosure, since the zero-phase current toward the power supply line of the three-phase motor is directly detected, it is possible to measure the resistance component leakage current (Ior) that only shows the insulation deterioration state of the three-phase motor.

In addition, the conductive member has conductivity, and each conductive member is fixedly supported by and penetrates the through hole of the zero-phase current transformer in an insulated manner. Therefore, since the position of the power supply line of the three-phase motor is fixed in the through hole of the zero-phase current transformer, the phase and magnitude of the residual current will not change. As a result, the error factor can be eliminated, and the aforementioned error factor refers to changing the magnitude and phase of the residual current according to the penetration position of each three-phase wiring in the through hole of the zero-phase current transformer. Therefore, the residual current can be corrected, and the leakage current of the minute resistance component of nA level can be measured.

In addition, the insulation measurement device according to the aspect of the present disclosure further includes a control unit that uses at least one penetration current detected by the penetration current rectifier to correct the detected zero-phase current and measure the resistance component leakage Current.

With this, since at least one penetration current detected by the penetration current rectifier is used to correct the measured zero-phase current, an error factor based on the motor capacity of the three-phase motor can be eliminated. In addition, since the resistance component leakage current is measured by the control unit, the true resistance component leakage current (Ior) can be obtained after the zero-phase current is corrected and measured.

Therefore, it is possible to provide an insulation measurement device and an insulation measurement method which can surely remove the error factor at the time of detection and accurately obtain the true resistance component leakage current flow. What's more, because the insulation deterioration of the three-phase motor can be detected early, it can be preserved in a planned way.

In the insulation measuring device of the aspect of the present disclosure, the conductive member preferably has rigidity.

Thereby, when each conductive member is fixedly supported inside the through hole of the zero-phase current regulator, a simple support member can be used and the conductive member cannot be easily moved.

In addition, in the insulation measurement device of this embodiment, the control unit may include a first measurement zero-phase current acquisition unit that measures the zero-phase from the zero-phase current detected by the zero-phase current comparator The magnitude and phase of the current to obtain the measured zero-phase current; the first correction unit uses the residual current correction value corresponding to any penetrating current to calculate the corresponding correction of the penetrating current corresponding to the penetrating current detected by the penetrating current ratio. Value, and use the current corresponding correction value for the aforementioned measured zero-phase current to correct the measured zero-phase current and obtain the corrected zero-phase current; a first voltage acquisition unit that measures the phase of at least one of the aforementioned conductive members The magnitude and phase of the voltage between the wirings and the voltage of the conductive component are obtained; the first calculation unit calculates the resistance component leakage current by using the corrected zero-phase current and the conductive component voltage.

With this, the first measured zero-phase current acquisition unit measures the magnitude and phase of the zero-phase current from the zero-phase current detected by the zero-phase current comparator, and obtains the measured zero-phase current.

In addition, the first correction unit uses the residual current correction value corresponding to any penetrating current, calculates the current corresponding correction value corresponding to the penetrating current detected by the penetrating current ratio, and uses the current corresponding correction for measuring the zero-phase current Value, correct the measured zero-phase current, and find the corrected zero-phase current. This corrected zero-phase current shows close to true zero-phase current.

Next, the first voltage acquiring unit measures the magnitude and phase of the voltage between the phase wires of at least one of the conductive members, and acquires the conductive member voltage. The first calculation unit calculates the resistance component leakage current by the corrected zero-phase current and the voltage of the conductive member.

As a result, specifically, it is possible to provide an insulation measurement device that can surely remove the error factor at the time of detection and accurately obtain the true resistance component leakage current with good accuracy.

Furthermore, in the insulation measurement device according to the aspect of the present disclosure, the first correction unit obtains a residual current correction value corresponding to any through current in advance from the first residual current and the second residual current. The current includes an error, which corresponds to the magnitude of the first through current detected by the through current than the current penetrator when the first through current flows through the conductive member; the second residual current includes an error, which corresponds to the second When the penetrating current flows through the conductive member, the magnitude of the second penetrating current detected by the penetrating current is greater than that of the current penetrator.

In other words, the applicant system can determine that the magnitude of the through current and the magnitude of the residual current vary linearly. Therefore, a residual current correction value corresponding to an arbitrary through current is prepared as a correction formula in advance.

Specifically, because the correction formula corresponding to the correction value of the residual current of any penetration current can be expressed as a linear expression of the penetration current, the first residual current when the first penetration current flows and the second residual current when it flows For the second residual current, the slope and intercept of the correction formula can be obtained. As a result, the residual current correction value corresponding to any through current can be obtained.

Therefore, since the correction formula can be used to determine the correction value of the residual current that changes according to the magnitude of the through current, the time for the user to correct can be saved, and a convenient insulation measurement device can be provided.

In the insulation measurement device according to the aspect of the present disclosure, three of the through-current current transformers can be provided, and each of them detects the through-current flowing through each of the conductive members.

In other words, there is a case where current imbalance occurs due to the deterioration of the power supply environment, and the through current changes in each phase. In other words, the through currents with three-phase wiring are different. As a result, the correction value of the residual current changes according to the imbalance of the current passing through each phase.

However, in the insulation measurement device of the aspect of the present disclosure, since three penetrating current comparators are provided to separately detect the penetrating current flowing through each conductive member, it is possible to continuously monitor by measuring the penetrating current of each phase Unbalanced through current. Therefore, it is possible to correct the imbalance of the matching current.

In addition, in the insulation measurement device according to the aspect of the present disclosure, the control unit can include: a second measurement zero-phase current acquisition unit that measures the zero-phase current detected by the zero-phase current transformer The magnitude and phase of the zero-phase current to obtain the measured zero-phase current; the second correction unit is to obtain the correction value of the residual current corresponding to any penetrating current in advance, and to calculate the response to the above penetrating current ratio. The detected current corresponding to each of the through currents flowing through the conductive members corresponds to the correction value, and the current corresponding correction value is used for the measured zero-phase current to correct the measured zero-phase current and obtain the corrected zero-phase current; The second voltage acquisition part, which measures the magnitude and phase of the voltage between the phase wires of the conductive member, and obtains the voltage of the conductive member; the second calculation part, which calculates from the corrected zero-phase current and the conductive member voltage The aforementioned resistance component leakage current.

With this, the second measured zero-phase current acquisition unit measures the magnitude and phase of the zero-phase current from the zero-phase current detected by the zero-phase current transformer, and obtains the measured zero-phase current.

In addition, the second correction unit calculates the correction value of the current corresponding to each of the through currents detected by the through current ratio while calculating the residual current correction value corresponding to any through current in advance, and measures the zero phase The current uses the corresponding correction value of the current to correct the measured zero-phase current and obtain the corrected zero-phase current. This corrected zero-phase current shows close to true zero-phase current.

Next, the second voltage acquiring unit measures the magnitude and phase of the voltage between the phase wires of the conductive member, and acquires the voltage of the conductive member. The second calculation unit calculates the leakage current of the resistance component by the corrected zero-phase current and the voltage of the conductive member.

As a result, specifically, in the case where an unbalanced through current flows through each conductive member, it is possible to provide an insulation measurement device that can surely remove the error factor at the time of detection and accurately obtain the true Resistance component leakage current.

In the insulation measuring device according to the aspect of the present disclosure, the aforementioned control unit can be provided inside a housing made of a shielding material that shields electricity and magnetism.

In this way, by covering the control portion with a housing made of a shielding material, the control portion can be isolated from minute noise. In this way, errors in induced noise can be reduced, and minute current measurements of nA level can be performed.

In addition, the present disclosure is not limited to the above-mentioned embodiments, various changes can be made within the scope shown in the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in Within the technical scope of this disclosure. In addition, new technical features can be formed by combining the technical means disclosed in each embodiment.

1: power supply

2: three-phase motor

10A: Insulation measuring device

11: busbar (conductive parts)

12: ZCT (ZCT)

12a, 13a: through hole

13: through current ratio (CT)

14: Control Department

14a: Measurement zero-phase current acquisition section (first measurement zero-phase current acquisition section)

14b: Correction section (first correction section)

14c: Voltage acquisition unit (first voltage acquisition unit)

14d: Calculation Department (First Calculation Department)

Claims (8)

An insulation measuring device that measures the leakage current of the resistance component of the three-phase wiring connected from the power supply to the three-phase motor. It includes: each conductive component, which is connected to the three-phase wiring respectively; It has through holes, fixedly supports each of the conductive members in an insulated manner and allows each of the conductive members to pass through the through holes, and detects a zero-phase current synthesized by each through current flowing through each of the conductive members; a through current ratio , Which detects the penetrating current flowing through at least one of the aforementioned conductive members; and the control section, which uses a residual current correction value corresponding to any penetrating current and calculates at least one of the aforementioned corresponding to the penetrating current detected by the penetrating current The current correction value of the through current corrects the detected zero-phase current, and measures the resistance component leakage current. The insulation measuring device according to claim 1, wherein the conductive member has rigidity. The insulation measurement device according to claim 1 or 2, wherein the control unit includes: a first measurement zero-phase current acquisition unit that measures the zero from the zero-phase current detected by the zero-phase current comparator The magnitude and phase of the phase current, and the measured zero-phase current is obtained; the first correction unit uses the residual current correction value corresponding to any penetrating current to calculate the penetrating current corresponding to the penetrating current detected by the penetrating current The current corresponds to the correction value, and then the current corresponding correction value is used to correct the measured zero-phase current relative to the measured zero-phase current, and the corrected zero-phase current is obtained; A first voltage acquisition unit, which measures the magnitude and phase of the voltage between phase wires of at least one of the conductive members, and obtains the conductive member voltage; a first calculation unit, which uses the corrected zero-phase current and the conduction The component voltage calculates the resistance component leakage current. The insulation measurement device according to claim 3, wherein the first correction unit obtains in advance a residual current correction value corresponding to any through current from the first residual current and the second residual current; and the first residual The current system includes that when the first through current flows through the conductive member, an error due to the magnitude of the first through current is detected in the through current than the current detector; and the second residual current includes that the second through current flows through In the case of the conductive member, the error detected by the penetrating current ratio due to the magnitude of the second penetrating current. The insulation measuring device according to claim 1 or 2, wherein three of the penetrating current comparators are provided to detect penetrating currents flowing through the conductive members. The insulation measurement device according to claim 5, wherein the control unit includes: a second measurement zero-phase current acquisition unit that measures the zero-phase current from the zero-phase current detected by the zero-phase current comparator The size and phase of the measured zero-phase current are obtained; the second correction unit uses the residual current correction value corresponding to any penetrating current to calculate the current corresponding to the penetrating current detected by the penetrating current than the current transformer Corresponding to the correction value, the current corresponding correction value is used to correct the measured zero-phase current with respect to the measured zero-phase current, and the corrected zero-phase current is obtained; the second voltage acquisition unit measures the phase of the conductive member The size and phase of the voltage in the wiring room, and obtain the voltage of the conductive parts; The second calculation unit calculates the resistance component leakage current based on the corrected zero-phase current and the conductive member voltage. The insulation measurement device according to claim 1 or 2, wherein the control unit is provided inside a casing made of a shielding material that shields electricity and magnetism. An insulation measurement method that measures the leakage current of the resistance component of the three-phase wiring connected from the power supply to the three-phase motor. It includes: a setting step, which is to set each conductive component that connects the three-phase wiring separately; zero-phase current detection The step is to fix and support each of the conductive members in an insulated manner through the through holes in a zero-phase current transformer, and detect the zero-phase current synthesized by the through currents flowing through the conductive members ; Penetrating current detection step, which is in the penetrating current comparator, detects the penetrating current flowing through at least one of the aforementioned conductive parts; and measuring step, which uses the residual current correction value corresponding to any penetrating current, and the calculation factor should be in the aforementioned The at least one current correction value of the penetrating current detected by the penetrating current is used to correct the detected zero-phase current, and the resistance component leakage current is measured.

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