JP2010217019A - Insulation grounding monitoring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems wherein construction is difficult since installation locations overlap when constructing an insulated state monitoring device and an earth leakage grounding protection device to electrical energy transformation facilities, where the insulated state monitoring device of a low-voltage electric path and the earth leakage grounding protection device are manufactured as separated products each, and determination of a system to be adopted is difficult in many cases since the insulated state monitoring device includes a plurality of different detection systems of which each system differs in each insulated state detection performance, and load facilities are not fixed especially when designing newly installed electric equipment. <P>SOLUTION: Insulated state monitoring elements having different detection systems are integrated with earth leakage grounding protection elements to compose an insulation grounding monitoring unit for each system, and the insulation grounding monitoring units having different detection systems of insulated states and earth leakage grounding monitoring units are set to be in mutually freely replaceable device configurations, thus creating the insulation grounding monitoring device for mixedly using the respective systems. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to an insulation state monitoring device and a ground fault protection device for ensuring electrical safety.

As a response to earth faults on electric circuits, as a ground fault protection device aiming at `` protection measures against ground faults '', it is manufactured with standards such as earth fault relay, earth leakage breaker and earth leakage relay, earth leakage fire alarm The ones used are mainly used.
In addition, in response to the prevention of accidents involving the deterioration of the insulation of the circuit ground, the Agency for Natural Resources and Energy "intended to maintain the safety level of electrical equipment and open the way to improve the efficiency of safety operations" in 1984. There is an “apparatus capable of accurately monitoring the insulation state of low-voltage paths” as defined in the amendment of the Circular (40 Public Office No. 593) (59 Capital Agency No. 7400). Regarding the “Guidelines for Handling” (Technical Department Technical Section Manager Notification), technical requirements for Io-type and Igr-type insulation state monitoring devices have been defined and are becoming popular.
This is also described as “low voltage insulation monitoring device” in 230-1, 230-4, etc. of the private standard “Private Electricity Work Safety Management Regulations (JEAC-8021-2006)” recently established.

The following explains how to use these devices in the design of new electrical equipment. First, as a ground fault protection device, a ground fault relay, ground fault relay, ground fault circuit breaker, etc.・ Electric leakage prevention circuit breakers installed in accordance with occupational safety and health regulations are selected and adopted from the viewpoints of ground fault, accident prevention, fire prevention, and electric shock prevention.
Next, if it is difficult to measure the insulation resistance by powering off the electrical equipment due to the circumstances of the electricity customer, or if an accidental insulation deterioration that occurs during the use of electricity is discovered and dealt with early, a ground fault can be dealt with. When there is a need to prevent it, or when there is a purpose to replace patrols, inspections, and inspections performed by humans, an insulation state monitoring device can be installed from the Io method, Ior method, Igr method, etc. A method that fits the electrical characteristics of the system is selected and adopted.

Japanese Patent No. 3920163

Japanese Patent Application No. 48-53149 (Japanese Patent Laid-Open No. 50-2142)

"Production and Electricity" April 30, 1992, published by the NEC Association "Overview and Features of Igr Insulation Monitoring System" Kozo Kataoka

April 2007, “National Electric Work Maintenance Regulations (JEAC8021-2006)” published by the NEC Association

Legal grounds on which “Earth leakage ground fault protection device” installed as “Protection against ground fault” and “Insulation state monitoring device” installed for the purpose of constantly monitoring “insulation performance of low-voltage circuit” differ Therefore, since each product has been commercialized as a device with a different name for each purpose, when installing both the “earth leakage ground fault protection device” and the “insulation state monitoring device” in the distribution facility design, each is separately There is a problem that both products must be installed at the same location.

When both products are installed in the same location, both are devices with similar functions, so the installation of ZCT as a current sensor and the installation location of the device itself will overlap, making it very difficult to construct equipment in a narrow substation facility. It becomes.
In addition, if the circuit section where ZCT can be installed is short, ZCT of both products will approach and it will be difficult to pass the test line through the single ZCT not only in the facility work, but also in the individual test work of both products. Cause trouble.

As the method of the “insulation state monitoring device”, there are an Io method insulation state monitoring device and an Igr method insulation state monitoring device that rely on operation notification, and the Ior method insulation state monitoring operation similar to that of Patent Document 2 in private standards. There are devices.
The Igr insulation detection method is described in “Non-Patent Document 2” 230-4 [Description]. According to (4), although it is said that it is the best among these methods, if this method is employed for all monitored electric circuits, the cost becomes high.
On the other hand, the low cost Io method and Ior method have a serious problem that the insulation of the neutral line (ground phase) of the monitored circuit cannot be detected, and the neutral point grounding distribution system of the transformer In this case, if the insulation is degraded evenly, such as when the load is submerged, this cannot be detected or a large error occurs. In addition, the ground capacitance value of the load equipment, the magnitude of the constant leakage current, and the unbalanced ground capacitance Therefore, there is a problem in principle that the detected value of the insulation state increases or decreases.
Because of these circumstances, there is a problem that it is difficult to select the method because the ground electrical characteristics of the load facility cannot be clearly grasped at the time of the new design of the electrical facility.

Patent Document 1 describes a method in which the Io and Igr type insulation state monitoring devices can be easily replaced and interchanged. However, in this case as well, there is a problem that a ground fault protection device must be separately installed. .

Insulation state monitoring devices are mainly developed for small-scale power receiving / transforming facilities, and “Selective insulation” is described in “Non-patent document 1” as a device that has been extended to power distribution facilities for large-scale general consumers. An Igr type insulation monitoring device incorporating a ground fault overcurrent element has been introduced as a device capable of ground fault monitoring. However, in this case as well, the incorporation of the ground fault overcurrent element is a drawback of the Igr method. In the case of a complete ground fault, the product is provided as a back-up protection function for the purpose of complementing the fact that the insulation deterioration voltage cannot be detected by eliminating the insulation monitoring voltage. The name does not have an expression that can be directly recognized as having a ground fault protection function.
Therefore, when installing both the “insulation state monitoring device” and the “earth leakage ground fault protection device” in the electrical equipment design, there is an example of an equipment design that uses a ground fault protection device together with the insulation state monitoring device. Many.

The ground fault protection device and insulation state monitoring device need to properly manage the soundness of the state monitoring function, but as a method of regular inspection of electrical equipment, there is a method of measuring insulation resistance by customary power failure. There are many cases where ZCT is installed in places where there is a risk of electric shock that can not be done without a power failure due to the fact that it has been established. It is one of the difficult issues to perform a state monitoring function test by the live system, such as conducting a confirmation test.

In the present invention, a ground fault monitoring unit is configured by a ground fault monitoring element, an Io insulation monitoring element and a ground fault monitoring element are combined to form an Io ground fault monitoring unit, The insulation monitoring element and the ground fault monitoring element are combined to constitute an Igr insulation ground fault monitoring unit.
These earth leakage ground fault monitoring unit, Io insulated ground fault monitoring unit and Igr insulated ground fault monitoring unit are of the same shape plug-in unit type, and the storage box as the platform has electrical connection portions, terminal portions and mechanical dimensions. The ground fault monitoring unit, the Io insulated ground fault monitoring unit, and the Igr insulated ground fault monitoring unit can be used in common, and the ground fault monitoring unit, the Io insulated ground fault monitoring unit, and the Igr insulated ground fault monitoring unit, Thus, an insulated ground fault monitoring device is configured in which the units can be interchanged and the units of different methods can be mixedly used.

In construction that constitutes an insulation ground fault monitoring device, a hot wire division that can connect an insulation monitoring voltage output without interrupting the monitored circuit in the ground wiring from the transformer neutral point or one end to the grounding electrode of the monitored circuit A relay terminal device is provided.

The insulation ground fault monitoring device is provided with a test terminal that can be connected to a ZCT test feeder and can perform an actual dynamic test operation.

In the present invention, the insulation state monitoring element and the earth leakage ground fault monitoring element are combined, and the function capable of monitoring the states of both "insulation performance of the low piezoelectric path" and "protection measures against ground fault" is unified as an insulation ground fault monitoring device. Configured. As a result, the ZCT mounting space and the device mounting space are almost halved compared to the prior art, and the assembly to the power distribution facility is facilitated.

The Io insulation ground fault monitoring unit is an Io and Igr compatible type insulation ground fault monitoring system that can be replaced with the Igr insulation ground fault monitoring unit. As a result, even if power equipment with a large capacitance is added to the load equipment, the Io insulated ground fault monitoring unit of the monitored circuit can be easily replaced with an Igr insulated ground fault monitoring unit that is not easily affected by the load equipment. Since it is possible, an efficient device configuration can be selected.

In addition, in selecting work for insulation monitoring and ground fault protection methods in the design of new equipment, the ground fault monitoring unit is configured with normal circuit load equipment as a ground fault protection measure for electrical circuits that do not require insulation monitoring. The Io insulated ground fault monitoring unit is suitable for low cost insulation and ground fault protection of the circuit, and the Igr insulated ground fault monitoring unit is suitable for the circuit load equipment with a large capacitance to the ground. Therefore, it is possible to easily replace these without requiring a power outage, and it becomes easy to select an insulation and ground fault protection device suitable for the circuit load characteristics.

Although the circuit load equipment with a large capacitance is estimated to be less than about 10% of the total load equipment, although it depends on the type of industry of the electric power consumer, the conventional equipment using the Igr type insulation state monitoring element is used for all circuits. Significant cost reduction compared to the method.

Since the hot wire interrupting relay terminal device 50 is provided in the middle of the ground wiring of the monitored circuit, it is possible to superimpose the insulation monitoring voltage at any time.
As a result, even when the construction of an inexpensive insulated ground fault monitoring device using only the Io insulated ground fault monitoring unit is used, the output of the insulation monitoring voltage is connected to the live wire interrupting relay terminal device 50 and superimposed as necessary. This makes it possible to use a portable Igr detection device in addition to ground phase ground fault detection. When the insulation information output of the Io insulated ground fault monitoring unit increases, insulation degradation is caused by the Igr method. Maintenance work has been made possible, such as by checking the measurement and confirming the location of insulation degradation with live lines.

“Isolation ground fault monitoring device”, “Insulated ground fault relay device” or “Insulation fault monitoring device” that expresses the purpose of the device name by enabling mutual interchange of Io and Igr insulation detection methods and the combined use of both. It can be used as a state monitoring device or relay that has both functions of “insulation performance of low piezoelectric circuit” and “protection measures against ground fault”. I was able to select the equipment with my heart.

The insulation ground fault monitoring unit of each system of the insulation ground fault monitoring device is provided with a test terminal that can pass the test current directly to the ZCT, so the operation check of the state monitoring device can be performed at any time without power failure of the electrical equipment. Can now be done in different ways.

FIG. 1 shows an embodiment of an insulation ground fault monitoring device using a ground fault monitoring unit in preparation for a case where a power failure is possible and insulation state monitoring is unnecessary but may be required in the future. (Example 1) FIG. 2 shows an embodiment in which the cheapest insulated ground fault monitoring device is configured using Io insulated ground fault monitoring units in all circuits. (Example 2) FIG. 3 shows an embodiment in which a circuit for superimposing an insulation monitoring voltage is added to the embodiment 2 so that a ground phase ground fault detection and a portable Igr detector can be used. (Example 3) Fig. 4 shows a ground fault monitoring unit for a load facility that can be inspected for insulation failure and does not require insulation monitoring, an Io ground fault monitoring unit for a normal circuit load facility, and a circuit load facility with a large ground capacitance. It is a typical example of an insulated ground fault monitoring apparatus adopting an Igr insulated ground fault monitoring unit as appropriate and adopting a hybrid configuration. Example 4 FIG. 5 is an example in which a ground fault protective relay and an Igr system insulation state monitoring device are constructed as an example of construction according to the prior art. (Conventional technology) FIG. 6 is an explanatory diagram illustrating a ground fault monitoring unit according to the first embodiment in a system diagram. (Explanation of earth leakage monitoring unit) FIG. 7 is an explanatory diagram showing the Io insulation ground fault monitoring unit of the second embodiment in a system diagram. (Io insulation ground fault monitoring unit illustration) FIG. 8 is an explanatory diagram regarding detection of a ground phase ground fault according to the third embodiment. (Explanation of the current that flows during ground phase ground fault) FIG. 9 is an explanatory diagram showing an Igr insulation ground fault monitoring unit constituting the fourth embodiment in a system diagram. (Explanation of Igr insulation ground fault monitoring unit)

The Io and Igr type insulation monitoring elements used for monitoring the “low piezoelectric path insulation performance” and the earth leakage ground fault monitoring element used as “protection measures against ground faults” are combined into a ZCT to provide Io insulation. The ground fault monitoring unit 20 and the Igr insulated ground fault monitoring unit 30 are configured. Further, the ground fault monitoring unit 40 is configured only by the ground fault monitoring element, and the case, terminal, wiring, ZCT, etc. on the receiving side of the unit are provided. The system can be used in common for each type of ground fault monitoring unit.
Also, in the construction of the insulation ground fault monitoring device, a live wire interruption relay terminal device 50 is provided on the way from the transformer neutral point or one end to the grounding electrode of the monitored electric circuit, and the insulation monitoring voltage, etc. Can be connected.
Each insulation ground fault monitoring unit is equipped with a test terminal that allows a test current to flow directly to the ZCT test terminal, and the state monitoring is performed by directly applying a test operation to the test line of the ZCT regardless of the electrical characteristics of the insulation ground fault monitoring unit. The configuration is such that the actual operation of the device can be confirmed.

Also, at the time of designing a new facility, it is possible to inspect the insulation of the facility due to a power failure, and for electrical facilities that do not require an insulation state monitoring function, install a monitoring device with a ground fault monitoring unit and perform a power failure insulation test on the load. When equipment that is difficult to install is added, a rational equipment configuration is possible in which one of the insulation ground fault monitoring units is replaced.
The configuration having an insulation ground fault monitoring function of the present invention can be configured as a monitoring device having an output of status monitoring information and an alarm contact output, or a relay having only an alarm contact as an inexpensive and simple method.

In Example 1 (Fig. 1), it is possible to inspect insulation of electrical equipment due to a power outage at the time of designing the new equipment, and it is not necessary to monitor insulation status, but there is a possibility that an insulation status monitoring function will be required for future load expansion. It is an example of construction in case there is.
FIG. 6 illustrates the ground fault monitoring unit 40 and its connection relationship as a system diagram, and the portion surrounded by reference numeral 40 in the figure is the ground fault monitoring unit.
The test terminals 42 and 43 are arranged on the panel operation surface of the ground fault monitoring unit and connected to the test terminal of the ZCT 12 by a multi-core cable or the like from the connection terminal group 11a of the unit 40 through the connection terminal group 11b of the socket storage box. The
By supplying a test current equivalent to the current that actually flows due to a ground fault or the like to the test terminals 42 and 43, the actual dynamic function test of the ground fault monitoring unit can be easily performed in a live state. .

Example 2 (FIG. 2) is an example of construction in which an insulated ground fault monitoring device is configured by an Io insulated ground fault monitoring unit 20 with low cost according to the present invention for a normal circuit load facility 6.
In the conventional construction method of FIG. 5, ZCT, AZ and ZCT, BZ, the ground fault protection relay A, and the Igr system insulation state monitoring device B are used for one circuit to be monitored, but according to Example 2 of FIG. In the insulated ground fault monitoring device, ZCT 12 and Io insulated ground fault monitoring unit 20 are sufficient for each one, so the number of equipment is reduced by half, and the construction location and construction cost have been improved accordingly. Centralized and improved efficiency.

FIG. 7 illustrates the Io insulation ground fault monitoring unit 20 and its connection relationship as a system diagram, and the portion surrounded by reference numeral 20 in the figure is the Io insulation ground fault monitoring unit.
The Io insulation ground fault monitoring unit 20 includes an Io insulation monitoring element 21, a ground fault ground monitoring element 22, a test unit, a power supply unit, and the like.
Although the structure of the socket storage box 10 that receives the Io insulation ground fault monitoring unit 20 is shown in FIG. 7 as a structure that stores one unit, any number of units can be stored.
This socket storage box 10 is also used in common for each insulation ground fault monitoring unit and earth leakage ground fault monitoring unit.

The test terminals 23 and 24 are arranged on the panel operation surface of the insulation ground fault monitoring unit, and are connected to the test terminal of the ZCT 12 by a multi-core cable or the like from the connection terminal group 11a of the unit 20 through the connection terminal group 11b of the socket storage box. The
By making a test current equivalent to the current that actually flows due to an insulation deterioration fault or a ground fault to the test terminals 23 and 24, it is easy to test the actual dynamic function of the Io insulated ground fault monitoring unit in a live state. Can be done.

The live line interrupting relay terminal device 50 is used to connect the output of the insulation monitoring voltage to the ground line circuit of the monitored electric circuit with a live line. Usually, it is short-circuited by a short-circuit piece 52 connected to the transformer-side short-circuiting tool mounting terminal 51t and the ground-side short-circuiting tool mounting terminal 51e.

The third embodiment (FIG. 3) is one embodiment in which an insulation monitoring voltage superimposing device 60 is additionally connected to the second embodiment (FIG. 2). By superposing the insulation monitoring voltage, the Io insulation ground fault monitoring unit 20 can detect the ground phase ground fault of the monitored circuit.

FIG. 8 is an explanatory view of the ground fault detection of the ground phase S of the transformer secondary electric circuit 5.
The output of the insulation monitoring voltage generator 61 becomes the secondary output Es of the superposition transformer 62 via the hot wire interrupting relay terminal device 50, the transformer 1, and the monitored electric circuits R, S, T and the ground 4 (Ed ) Join in between. When the insulation resistance Rg between the ground phase S of the monitored circuit and the ground 4 decreases, a ground fault current ies = Es / (Rbd + Rg) flows due to the insulation monitoring voltage Es. Therefore, even in the Io insulated ground fault monitoring unit, the ground phase The ground fault of S can be detected.
The function of detecting a ground phase ground fault is particularly important in a substation equipment that performs equipotential grounding such as an integrated ground distribution system in which Rbd is zero.

Efficient maintenance work that checks the quality of insulation by resistive current component by Igr method by using portable Igr insulation detector by superimposing insulation monitoring voltage, and searches and traces insulation degradation point There is also an advantage that becomes possible.

In the extension work for shifting from the configuration of the second embodiment to the configuration of the third embodiment with the hot wires, the output circuit 63 of the insulation monitoring voltage superimposing device 60 is connected to the input terminals 53t and 53e of the hot wire interrupting relay terminal device 50. Then, the work is easily completed by removing the shorting tool 52 from the shorting tool attachment terminals 51t and 51e.

In the fourth embodiment (FIG. 4), the ground fault monitoring unit 40 is installed in the load facility 8 that can be inspected for insulation power outage and does not require insulation monitoring, the Io insulated ground fault monitoring unit 20 is installed in the normal circuit load facility 6, and the ground. The insulated ground fault monitoring device of the present invention is a hybrid configuration by appropriately adopting the Igr insulated ground fault monitoring unit 30 for the circuit load equipment 7 having a large capacitance and the ground wire 2 of the transformer to which this action is applied. This is the most representative example.
When a load facility having a large ground capacitance is generated in the monitored circuit, the Io insulation ground fault monitoring unit 20 of the circuit is removed from the third embodiment, and the Igr insulation ground fault monitoring unit 30 is inserted instead. Is enough.
This work is produced by managing the design ground quality so that the insulation ground fault monitoring unit does not behave abnormally with respect to the removal and attachment on the live line, and can be performed at any time in the live line state.

FIG. 9 illustrates the Igr insulated ground fault monitoring unit 30 and its connection relationship as a system diagram. In FIG. 9, the portion surrounded by the reference numeral 30 is the Igr insulated ground fault monitoring unit.
The Igr insulation ground fault monitoring unit 30 includes an Igr insulation monitoring element 31, a ground fault ground monitoring element 32, a test unit, a power supply unit, and the like.

The test terminals 33, 34, and 35 are arranged on the panel operation surface of the insulation ground fault monitoring unit, and the test terminals and insulation of the ZCT 12 are connected by a multi-core cable or the like from the connection terminal group 11a of the unit 30 to the connection terminal group 11b of the socket storage box. It is connected to the monitoring voltage input circuit 13, the ground electrode 4, and the like.
For the actual test of the Igr insulation monitoring element, a test insulation insulation resistor corresponding to the assumed insulation deterioration failure is connected to the test terminals 33 and 35 so that the actual insulation deterioration failure occurs in the monitored circuit. Confirmation of the actual operation of the Igr insulation monitoring element when it occurs can be easily performed while still live.
That is, the test terminal 35 is connected to the ground electrode 4, the test terminal 33 is connected to the transformer side lt 2 of the second test winding of the ZCT 12, and the other end kt 2 thereof is connected to the ground line 2 of the transformer 1. The connected simulated insulation resistor for testing is equivalently equivalent to being connected between the transformer secondary circuit 5 and the ground 4 through the grounding wire 2 of the transformer 1, so that the actual detection of the insulation state is effective. You can test.
Of course, the test terminal 33 can be connected directly to the ground line 2 of the transformer 1 or the secondary circuit of the transformer 1, but it is necessary to sufficiently consider the power consumption of the resistor and the safety of the test circuit components. is there.

As for the test of the earth leakage ground fault monitoring element 32, the test of the actual dynamic function can be easily performed in a live line state by supplying a test current equivalent to the current actually flowing due to a ground fault or the like to the test terminals 33 and 34. Can be done.
In FIG. 9, the test terminals 33 and 34 are connected to the second test line (kt2, lt2), but the first test line (kt, lt) can also be used.

1 Transformer of monitored circuit 2 Transformer or grounding line of circuit 3 Transformer grounding pole (Eb)
4 Grounding structures (Ed) of buildings and other grounding structures
5 Secondary circuit of transformer 6 Normal circuit load equipment 7 Circuit load equipment with a lot of ground capacitance 8 Electric load equipment that is easy for power failure and does not require insulation monitoring 10 Socket housing box 11 for insulation ground fault monitoring device Plug-in Connector terminal group 11a Connector terminal group 11b on the unit side Connector terminal group 12 on the socket storage box side ZCT of insulation ground fault monitoring device
13 Input circuit for insulation monitoring voltage 20 Io insulation ground fault monitoring unit 21 of insulation ground fault monitoring device Io insulation monitoring element 22 of Io insulation ground fault monitoring unit Earth leakage monitoring element 23 of Io insulation ground fault monitoring unit Io insulation ground fault Test terminal L side 24 of the monitoring unit Test terminal K side of the Io insulation ground fault monitoring unit 25 Test switch of the earth fault monitoring element of the Io insulation ground fault monitoring unit 26 Test switch of the Io insulation monitoring element of the Io insulation ground fault monitoring unit 30 Igr Insulated Ground Fault Monitoring Unit 31 Igr Insulated Ground Fault Monitoring Unit Igr Insulation Monitoring Element 32 Igr Insulated Ground Fault Monitoring Unit Ground Fault Monitoring Element 33 Igr Insulated Ground Fault Monitoring Unit Test Terminal L Side 34 Igr Insulated Ground Fault Monitoring Unit Test Terminal K Side 35 Igr Insulated Ground Fault Monitoring Unit Test Terminal Ed Side 36 Ig Test switch 37 for ground fault monitoring element of insulation ground fault monitoring unit Test switch 40 for Igr insulation monitoring element of insulation ground fault monitoring unit 40 Ground fault monitoring unit 41 of ground fault monitoring device Ground fault of ground fault monitoring unit Fault monitoring element 42 Earth fault monitoring unit test terminal L side 43 Earth fault monitoring unit test terminal K side 44 Earth fault monitoring element test switch 50 of earth fault monitoring unit Hot line of monitored circuit ground line Interrupting relay terminal device 51e Grounding side short-circuiting tool mounting terminal 51t of live-wire interrupting relay terminal device Transformer-side shorting device mounting terminal 52 of the live-wire interrupting relay terminal device Short-circuiting relay terminal device for hot-wire interruption Tool 53e Ground-side input terminal 53t of live-wire interrupt relay terminal device Transformer-side input terminal 60 of live-wire interrupt relay terminal device Insulation monitoring voltage superimposing device 61 Insulation monitoring voltage generator 6 2 Insulation monitoring voltage superimposing transformer 63 Superimposed transformer circuit grounding line A Ground fault protection relay AZ Ground fault protection relay ZCT
B Igr system insulation state monitoring device BZ Igr system insulation state monitoring device ZCT
Es Insulation monitoring voltage applied between the monitored circuit and the ground ies Current Kt ZCT12 flowing through Rg by the insulation monitoring voltage K-side terminal lt of the first test winding of ZCT12 L-side terminal kt2 of the first test winding of ZCT12 Test side K-side terminal lt2 ZCT12 second test side L-side terminal Rbd Earth resistance Rg between transformer grounding electrode 3 and equipment grounding electrode 4 Between grounding phase S of circuit 5 and equipment grounding electrode 4 Insulation resistance S Ground phase of circuit 5

Claims (5)

Plural insulation status monitoring elements and ground fault monitoring elements with different insulation detection methods are combined to form a multiple insulation ground fault monitoring unit, and each insulation ground fault monitoring unit is a plug-in unit type with the same shape. The socket storage box that serves as a platform is a structure that can be used in common with multiple types of insulation ground fault monitoring units for electrical connection, terminal, and mechanical dimensions, and each unit can be interchanged freely. Insulated ground fault monitoring device.
Plug-in unit having the same shape for an Io insulation ground fault monitoring unit comprising an Io insulation monitoring element and a ground fault monitoring element, and an Igr insulation ground fault monitoring unit comprising an Igr insulation monitoring element and a ground fault monitoring element Io insulation ground fault monitoring as a structure that can be used in common for both the Io insulated ground fault monitoring unit and the Igr insulated ground fault monitoring unit. An insulated ground fault monitoring apparatus characterized in that the unit and the Igr insulated ground fault monitoring unit can be interchanged freely. An Io relay terminal that can connect the insulation detection signal with a live line in the middle of the transformer neutral point or one end of the monitored circuit from the ground to the grounding pole, allowing the insulation monitoring voltage output to be superimposed at any time Insulated ground fault monitoring device and power distribution equipment constituted by an insulated ground fault monitoring unit. Plug-in unit having the same shape for an Io insulation ground fault monitoring unit comprising an Io insulation monitoring element and a ground fault monitoring element, and an Igr insulation ground fault monitoring unit comprising an Igr insulation monitoring element and a ground fault monitoring element The storage box used as a platform of the Io insulation ground fault monitoring unit has a structure in which electrical connection portions, terminal portions, and mechanical dimensions can be used in common for the Io insulated ground fault monitoring unit and the Igr insulated ground fault monitoring unit. And an Igr insulated ground fault monitoring unit, and an insulation ground fault monitoring apparatus and a power distribution facility provided with a test connection terminal that allows a test current to flow directly to the ZCT test terminal. A ground fault monitoring unit comprising a ground fault monitoring element, an Io insulation ground monitoring unit comprising an Io insulation monitoring element and a ground fault monitoring element, an Igr insulation monitoring element and a ground fault monitoring element The Igr insulation ground fault monitoring unit has the same shape as the plug-in unit type, and the socket storage box as the platform has a structure in which electrical connection portions, terminal portions, and mechanical dimensions can be commonly used for each unit. Units can be interchanged with each other, and an interrupt relay terminal that can connect an insulation detection signal with a live wire is provided on the ground wire connected from the transformer of the monitored circuit to the ground electrode. And an insulation ground fault monitoring device provided with a test connection terminal that allows a test current to flow directly to the test terminal of the ZCT.

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