A method and device for monitoring insulation of a transformer gas relay

Abstract

The present invention provides an insulation monitoring method and device for a transformer gas relay, which relates to the technical field of electric power equipment. A power supply, a locking relay, and an outlet relay are provided in an outlet circuit of the gas relay. The method comprises: obtaining first voltage sampling data of the locking relay and the outlet relay, second voltage sampling data of the outlet contact of the gas relay, and first current sampling data of the outlet circuit; determining the insulation state of the gas relay based on the first voltage sampling data, the second voltage sampling data, and the first current sampling data; and controlling whether to send an alarm signal based on the insulation state. The insulation monitoring method of the present invention can be used to prevent the insulation degradation problem of the outlet contact of the gas relay. When the insulation state is in an abnormal state, the maintenance personnel can be reminded in time and as early as possible by sending an alarm signal, so as to find and eliminate the fault as soon as possible, avoid the gas relay from malfunctioning, and perform insulation inspection and other work without power outage.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power equipment, and in particular to an insulation monitoring device and method for a transformer gas relay. Background Art

[0002] A gas relay is a protective device used in transformers, usually installed on the top of the transformer. When certain faults occur in the transformer, gas will be generated or oil will surge. The gas relay can take corresponding actions, thereby issuing an alarm signal or cutting off the transformer. In the prior art, the aging of the secondary cable of the gas relay and the degradation of the quality of the circuit components will lead to the degradation of the insulation between the cable cores. In addition, the junction box of the gas relay is usually located in an outdoor environment. Once the junction box is flooded, the insulation of the secondary cable will be reduced, which may easily lead to the misoperation of the gas protection. In addition, in order to check the status of the gas relay, the equipment in the secondary circuit of the gas relay must be powered off, which cannot guarantee the timely discovery of insulation abnormalities. Summary of the invention

[0003] The main purpose of the present invention is to provide an insulation monitoring method and device for a transformer gas relay to solve at least one of the technical problems in the prior art that the gas relay may have gas protection malfunction, and the inspection means are backward and cannot detect insulation abnormalities in time.

[0004] In order to achieve the above-mentioned purpose, the present invention provides an insulation monitoring method for a transformer gas relay, wherein an output circuit of the gas relay is provided with a power supply, a locking relay and an output relay, and the insulation monitoring method comprises: obtaining first voltage sampling data of the locking relay and the output relay, second voltage sampling data of the output contact of the gas relay, and first current sampling data of the output circuit; determining the insulation state of the gas relay based on the first voltage sampling data, the second voltage sampling data and the first current sampling data; and controlling whether to issue an alarm signal based on the insulation state of the gas relay.

[0005] Furthermore, the alarm signal includes a local alarm signal and a remote alarm signal.

[0006] Furthermore, the determining of the insulation state of the gas relay based on the first voltage sampling data, the second voltage sampling data and the first current sampling data includes: when the first voltage sampling data is greater than a first voltage threshold, or the second voltage sampling data is less than a second voltage threshold, or the first current sampling data is greater than a first current threshold, determining that the insulation state is in an abnormal state.

[0007] Furthermore, the obtaining of the first voltage sampling data of the locking relay and the output relay, the second voltage sampling data of the output contact of the gas relay, and the first current sampling data of the output loop also includes: obtaining the first humidity sampling data in the junction box of the gas relay; the determining of the insulation state of the gas relay based on the first voltage sampling data, the second voltage sampling data and the first current sampling data includes: when the first voltage sampling data is greater than a first voltage threshold, or the second voltage sampling data is less than a second voltage threshold, or the first current sampling data is greater than a first current threshold, or the first humidity sampling data is greater than a first humidity threshold, determining that the insulation state is in an abnormal state.

[0008] Further, after determining the insulation state of the gas relay based on the first voltage sampling data, the second voltage sampling data and the first current sampling data, it includes: determining whether to disconnect the locking relay based on the system state of the transformer and the insulation state.

[0009] Furthermore, the method of determining whether to disconnect the locking relay based on the system state and the insulation state of the transformer includes: acquiring three-phase voltage data and three-phase current data of the transformer; determining the system state based on the three-phase voltage data and the three-phase current data; when the system state is in a closed state and the insulation state is in an abnormal state, determining to disconnect the locking relay to disconnect the export loop; and when the system state is in a startup state, determining not to disconnect the locking relay to open the export loop.

[0010] Furthermore, the system state is determined based on the three-phase voltage data and the three-phase current data, including: at least one phase voltage in the three-phase voltage data is less than a third voltage threshold, and at least one phase current in the three-phase current data is greater than a second current threshold, and the system state is determined to be in a startup state; otherwise, the system state is determined to be in a shutdown state.

[0011] The present invention also provides an insulation monitoring device for a transformer gas relay, wherein an output circuit of the gas relay is provided with a power supply, a locking relay and an output relay, and the insulation monitoring device comprises: a data acquisition module, used to obtain first voltage sampling data of the locking relay and the output relay, second voltage sampling data of the output contact of the gas relay, and first current sampling data of the output circuit; a logic judgment module, used to determine the insulation state of the gas relay based on the first voltage sampling data, the second voltage sampling data and the first current sampling data; and an alarm module, used to control whether to issue an alarm signal based on the insulation state of the gas relay.

[0012] Furthermore, the data acquisition module is also used to obtain the first humidity sampling data in the junction box of the gas relay; the logic judgment module is used to determine the insulation state of the gas relay based on the first voltage sampling data, the second voltage sampling data, the first current sampling data and the first humidity sampling data.

[0013] Furthermore, the data acquisition module is also used to obtain the three-phase voltage data and three-phase current data of the transformer; the logic judgment module is also used to determine the system status of the transformer based on the three-phase voltage data and the three-phase current data; the insulation monitoring device also includes a locking control module, which is used to determine to disconnect the locking relay to disconnect the export circuit when the system status is in a closed state and the insulation status is in an abnormal state; when the system status is in a startup state, determine not to disconnect the locking relay to open the export circuit.

[0014] The insulation monitoring method of the present invention can be used to prevent the insulation degradation problem of the outlet contacts of the gas relay caused by aging of the secondary cable, degradation of the quality of the loop components, water ingress and moisture in the junction box, etc. The insulation state of the gas relay is determined by the first voltage sampling data, the second voltage sampling data, the first current sampling data, etc., so as to control whether to send an alarm signal according to the insulation state. When the insulation state is in a normal state, it will not affect the transformer and the gas relay; when the insulation state is in an abnormal state, an alarm signal is sent to remind the maintenance personnel in time and as early as possible, so as to find and eliminate the fault as soon as possible, avoid the gas relay from malfunctioning, and perform insulation inspection and other work without power outage.

[0015] The insulation monitoring device of the present invention has all the beneficial effects of the above insulation monitoring method, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0017] Figure 1 A first step diagram of the insulation monitoring method provided by an embodiment of the present invention;

[0018] Figure 2 A second step diagram of the insulation monitoring method provided by an embodiment of the present invention;

[0019] Figure 3 A schematic diagram of an outlet circuit of a gas relay provided in an embodiment of the present invention;

[0020] Figure 4 A schematic diagram of an insulation monitoring device provided by an embodiment of the present invention;

[0021] Figure 5 A logic diagram of the insulation monitoring method provided in an embodiment of the present invention.

[0022] The above drawings include the following reference numerals:

[0023] 1. Latching relay; 2. Output relay; 3. Output contact. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0026] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0027] The present invention provides a method for monitoring the insulation of a transformer gas relay. Figure 1 and Figure 3 As shown, the outlet circuit of the gas relay is provided with a power supply, a locking relay 1, and an outlet relay 2, and the insulation monitoring method includes:

[0028] S100, acquiring first voltage sampling data of the locking relay 1 and the outlet relay 2, second voltage sampling data of the outlet contact 3 of the gas relay, and first current sampling data of the outlet circuit;

[0029] S200, determining the insulation state of the gas relay based on the first voltage sampling data, the second voltage sampling data and the first current sampling data;

[0030] S310. Based on the insulation state of the gas relay, control whether to issue an alarm signal.

[0031] Combination Figure 1 and Figure 3 As shown, Figure 3 The diagram is a schematic diagram of the outlet circuit of the gas relay. The power supply can be arranged as shown in the figure with positive and negative electricity. The latching relay 1 is a normally closed element. When the insulation state is in a normal state, the insulation of the outlet contact 3 of the gas relay is infinite, and its secondary wiring uses a secondary cable with insulation between the cores greater than 10MΩ. The DC current of the outlet circuit is zero.

[0032] In step S100, the first voltage sampling data of the locking relay 1 and the outlet relay 2, the second voltage sampling data of the outlet contact 3 of the gas relay, and the first current sampling data of the outlet circuit are obtained. Figure 3 As shown, by sampling the voltages at both ends of the locking relay 1 and the output relay 2, the first voltage sampling data U is obtained.o1 By sampling the voltage between the output contacts 3, the second voltage sampling data U is obtained. o2 By sampling the DC current on the outlet loop, the first current sampling data I is obtained. o .

[0033] In step S200, the insulation state (including normal state and abnormal state) of the gas relay is determined based on the first voltage sampling data, the second voltage sampling data and the first current sampling data. When the insulation state is in the normal state, because the insulation at the outlet contact 3 is greater than 10MΩ, the first voltage sampling data U o1 is zero or close to zero, the second voltage sampling data U o2 Equivalent to the power supply voltage, usually 220V or 110V, the first current sampling data I o When the insulation state is in an abnormal state (for example, water enters the junction box, the contact is damp, the insulation performance of the secondary cable is reduced, etc.), it is equivalent to that the outlet contacts 3 are in a connected state. Since this process generally changes slowly from a normal state to an abnormal state, it will cause the first voltage sampling data U o1 Slowly increases, accordingly, the second voltage sampling data U o2 The output circuit will also generate a DC current, that is, the first current sampling data I o Gradually increase.

[0034] According to the first voltage sampling data U o1 , the second voltage sampling data U o2 , the first current sampling data I o In one embodiment, the step S200 specifically includes: when the first voltage sampling data is greater than a first voltage threshold, or the second voltage sampling data is less than a second voltage threshold, or the first current sampling data is greater than a first current threshold, determining that the insulation state is in an abnormal state.

[0035] In this embodiment, the first voltage threshold U t1 , the second voltage threshold U t2 , the first current threshold I t The specific value can be set as needed, and is not limited here. By setting the relevant threshold, it is possible to avoid problems such as the accidental triggering of subsequent alarm signals due to certain fluctuations in the system.

[0036] In step S310, based on the insulation state of the gas relay, it is controlled whether to issue an alarm signal. In one embodiment, when the insulation state of the gas relay is in an abnormal state, the alarm signal is controlled to be issued, wherein the alarm signal can be any signal such as sound, light, text, etc., to prompt the maintenance personnel to find the fault as early as possible; when the insulation state of the gas relay is in a normal state, the alarm signal is controlled not to be issued, that is, the insulation function of the outlet contact 3 of the gas relay is normal.

[0037] In another embodiment, the alarm signal includes a local alarm signal and a remote alarm signal. In this embodiment, the local alarm signal is an alarm device installed near the gas relay, which can promptly prompt the maintenance personnel to find the fault location, and the remote alarm signal can be an alarm device installed at other locations, which can prompt relevant personnel far away from the gas relay, thereby ensuring timely discovery and resolution of the fault.

[0038] In another embodiment, in the step S100, the first voltage sampling data of the locking relay 1 and the outlet relay 2, the second voltage sampling data of the outlet contact 3 of the gas relay, and the first current sampling data of the outlet loop are obtained, and the first humidity sampling data in the junction box of the gas relay is obtained; in the step S200, the insulation state of the gas relay is determined based on the first voltage sampling data, the second voltage sampling data and the first current sampling data, specifically including: when the first voltage sampling data is greater than the first voltage threshold, or the second voltage sampling data is less than the second voltage threshold, or the first current sampling data is greater than the first current threshold, or the first humidity sampling data is greater than the first humidity threshold, it is determined that the insulation state is in an abnormal state.

[0039] In this embodiment, the first humidity sampling data H in the junction box of the gas relay is obtained. o , the first humidity threshold H t You can set the specific value as needed. Figure 5 As shown in the figure, it is a control logic diagram of the action of the locking relay 1. When determining the insulation state, the first voltage sampling data is greater than the first voltage threshold, which is called the first voltage condition U o1 >U t1 The second voltage sampling data is less than the second voltage threshold, which is called the second voltage condition U o2 <U t2 The first current sampling data is greater than the first current threshold, which is called the first current condition I o >I t ; The first humidity sampling data is greater than the first humidity threshold, which is called the first humidity condition H o >H t. If at least one of the above-mentioned first voltage condition, second voltage condition, first current condition and first humidity condition is met, it can be determined that the insulation state is in an abnormal state. The insulation state is affected by factors such as aging of the secondary cable and moisture in the junction box. Therefore, by introducing multiple conditions to judge the insulation state, insulation problems of the gas relay can be discovered as early as possible, which is convenient for maintenance personnel to discover and eliminate faults as early as possible.

[0040] Furthermore, combined with Figure 2 As shown, after the step S200, that is, after the insulation state of the gas relay is determined based on the first voltage sampling data, the second voltage sampling data and the first current sampling data, the method includes:

[0041] S320: Determine whether to disconnect the locking relay 1 based on the system state and the insulation state of the transformer.

[0042] In this embodiment, after step S200, the insulation state of the gas relay is determined, and the system state is also introduced. The system state can be obtained from the three-phase voltage data and the three-phase current data in the transformer system. In step S320, whether to disconnect the locking relay 1 is determined comprehensively based on the system state and the insulation state, which specifically includes:

[0043] S321, obtaining three-phase voltage data and three-phase current data of the transformer;

[0044] S322, determining the system state based on the three-phase voltage data and the three-phase current data;

[0045] S3231, when the system state is in a closed state and the insulation state is in an abnormal state, determine to disconnect the locking relay 1 to disconnect the outlet circuit;

[0046] S3232. When the system state is in the startup state, determine not to disconnect the locking relay to open the export circuit.

[0047] Combination Figure 5 As shown, the system state (including the start state and the shutdown state, the start state means that the system voltage is started and the system current is started, and the shutdown state means that the system voltage is shut down and the system current is shut down) is determined by the three-phase voltage data (i.e., the system voltage) and the three-phase current data (i.e., the system current) of the transformer. If the system state is in the shutdown state and the insulation state is in an abnormal state, it is determined to disconnect the locking relay 1 so that the gas tripping protection is locked; if the system is in the start state, which is equivalent to a sudden change in the system voltage and the system current, it is determined not to disconnect the locking relay 1, which is equivalent to the locking relay 1 not acting, and the outlet circuit of the gas relay remains open.

[0048] In this way, the system status and insulation status are combined to determine whether to disconnect the locking relay 1 (i.e., whether to lock the gas trip protection), thereby avoiding the occurrence of transformer protection malfunction and ensuring the stable operation of the power grid.

[0049] In addition, after determining whether to disconnect the locking relay 1 based on the insulation status and system status, a delay t can be set, and the specific delay value can be set as needed to avoid the situation where a certain condition is met instantaneously due to system fluctuations, thereby ensuring that the insulation monitoring method can correctly control the action of the locking relay 1.

[0050] Further, in step S322, the system state is determined based on the three-phase voltage data and the three-phase current data, combined with Figure 5 As shown, specifically including:

[0051] If at least one phase voltage in the three-phase voltage data is less than the third voltage threshold (i.e., the system voltage is started), and at least one phase current in the three-phase current data is greater than the second current threshold (i.e., the system current is started), it is determined that the system state is in the started state; otherwise, it is determined that the system state is in the shut-down state.

[0052] In this embodiment, the system state is determined by the three-phase voltage data and the three-phase current data of the transformer, and when determining whether to disconnect the locking relay 1 later, the system state and the insulation state are combined to judge, which is conducive to avoiding malfunction of the transformer gas protection.

[0053] The insulation monitoring method of the present invention can be used to prevent the insulation degradation problem of the outlet contact 3 caused by aging of the secondary cable of the gas relay, degradation of the quality of the loop components, water ingress and moisture in the junction box, etc. The insulation state of the gas relay is determined by the first voltage sampling data, the second voltage sampling data, the first current sampling data, etc., so as to control whether to send an alarm signal according to the insulation state. When the insulation state is in a normal state, it will not affect the transformer and the gas relay; when the insulation state is in an abnormal state, an alarm signal is sent to remind the maintenance personnel in time and as early as possible, so as to find and eliminate the fault as soon as possible, avoid the gas relay from malfunctioning, and perform insulation inspection and other work without power outage.

[0054] The present invention also provides an insulation monitoring device for a transformer gas relay, Figure 3 As shown, the outlet circuit of the gas relay is provided with a power supply, a locking relay 1, an outlet relay 2, and a Figure 4 As shown, the insulation monitoring device comprises:

[0055] A data acquisition module, used to obtain the first voltage sampling data of the locking relay 1 and the outlet relay 2, the second voltage sampling data of the outlet contact 3 of the gas relay, and the first current sampling data of the outlet circuit;

[0056] a logic judgment module, used for determining the insulation state of the gas relay based on the first voltage sampling data, the second voltage sampling data and the first current sampling data;

[0057] The alarm module is used to control whether to send out an alarm signal based on the insulation state of the gas relay.

[0058] Step S100 in the insulation monitoring method can be implemented through the data acquisition module, that is, obtaining the first voltage sampling data of the locking relay 1 and the outlet relay 2, the second voltage sampling data of the outlet contact 3 of the gas relay, and the first current sampling data of the outlet circuit; step S200 in the insulation monitoring method can be implemented through the logic judgment module, that is, determining the insulation state of the gas relay based on the first voltage sampling data, the second voltage sampling data and the first current sampling data; step S310 in the insulation monitoring method can be implemented through the alarm module, that is, controlling whether to issue an alarm signal based on the insulation state of the gas relay.

[0059] The insulation monitoring device of the present invention can be used to prevent the insulation degradation problem of the outlet contact 3 caused by aging of the secondary cable of the gas relay, degradation of the quality of the loop components, water ingress and moisture in the junction box, etc. The insulation state of the gas relay is determined by the first voltage sampling data, the second voltage sampling data, the first current sampling data, etc., so as to control whether to send an alarm signal according to the insulation state. When the insulation state is in a normal state, it will not affect the transformer and the gas relay; when the insulation state is in an abnormal state, an alarm signal is sent to remind the maintenance personnel in time and as early as possible, so as to find and eliminate the fault as soon as possible and avoid malfunction of the gas relay.

[0060] In another embodiment, the data acquisition module is further used to obtain first humidity sampling data in the junction box of the gas relay; the logic judgment module is used to determine the insulation state of the gas relay based on the first voltage sampling data, the second voltage sampling data, the first current sampling data and the first humidity sampling data.

[0061] The first voltage sampling data, the second voltage sampling data, the first current sampling data and the first humidity sampling data are obtained through the data acquisition module, and the insulation state of the gas relay is determined based on the above sampling data through the logic judgment module, which is conducive to early detection of insulation degradation problems and early resolution.

[0062] In another embodiment, in combination Figure 4 As shown, the data acquisition module is also used to obtain the three-phase voltage data and three-phase current data of the transformer; combined Figure 5 As shown, the logic judgment module is also used to determine the system state of the transformer based on the three-phase voltage data and the three-phase current data; the insulation monitoring device also includes a locking control module, which is used to determine to disconnect the locking relay 1 to disconnect the export circuit when the system state is in a closed state and the insulation state is in an abnormal state; when the system state is in a startup state, determine not to disconnect the locking relay 1 to open the export circuit.

[0063] The system status is determined by the three-phase voltage data and three-phase current data of the transformer. When determining whether to disconnect the interlocking relay 1 later, the system status and insulation status are combined to determine whether to disconnect the interlocking relay 1 (i.e., whether to lock the gas trip protection) to avoid the occurrence of transformer protection malfunctions and ensure the stable operation of the power grid.

[0064] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0065] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0066] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for monitoring insulation of a transformer gas relay, characterized in that: The outlet circuit of the gas relay is provided with a power supply, a locking relay, and an outlet relay, and the insulation monitoring method comprises: Acquire first voltage sampling data of the locking relay and the outlet relay, second voltage sampling data of the outlet contact of the gas relay, first current sampling data of the outlet circuit, and first humidity sampling data in the junction box of the gas relay; Determining the insulation state of the gas relay based on the first voltage sampling data, the second voltage sampling data and the first current sampling data, comprising: determining that the insulation state is in an abnormal state when the first voltage sampling data is greater than a first voltage threshold, or the second voltage sampling data is less than a second voltage threshold, or the first current sampling data is greater than a first current threshold, or the first humidity sampling data is greater than a first humidity threshold; Based on the insulation state of the gas relay, control whether to issue an alarm signal; based on the system state of the transformer and the insulation state, determine whether to disconnect the locking relay, including: obtaining three-phase voltage data and three-phase current data of the transformer; determining the system state based on the three-phase voltage data and the three-phase current data; when the system state is in a closed state and the insulation state is in an abnormal state, determine to disconnect the locking relay to disconnect the outlet circuit; when the system state is in a startup state, determine not to disconnect the locking relay to open the outlet circuit.

2. The insulation monitoring method according to claim 1, characterized in that: The alarm signal includes a local alarm signal and a remote alarm signal.

3. The insulation monitoring method according to claim 1, characterized in that: The determining of the system state based on the three-phase voltage data and the three-phase current data includes: At least one phase voltage in the three-phase voltage data is less than a third voltage threshold, and at least one phase current in the three-phase current data is greater than a second current threshold, determining that the system state is in a startup state; Otherwise, it is determined that the system state is in a closed state.

4. An insulation monitoring device for a transformer gas relay, characterized in that: The outlet circuit of the gas relay is provided with a power supply, a locking relay, and an outlet relay, and the insulation monitoring device comprises: A data acquisition module, used for acquiring first voltage sampling data of the locking relay and the outlet relay, second voltage sampling data of the outlet contact of the gas relay, first current sampling data of the outlet circuit, first humidity sampling data in the junction box of the gas relay, three-phase voltage data and three-phase current data of the transformer; a logic judgment module, used for determining the insulation state of the gas relay based on the first voltage sampling data, the second voltage sampling data and the first current sampling data, including: when the first voltage sampling data is greater than a first voltage threshold, or the second voltage sampling data is less than a second voltage threshold, or the first current sampling data is greater than a first current threshold, or the first humidity sampling data is greater than a first humidity threshold, determining that the insulation state is in an abnormal state; and further used for determining whether to disconnect the locking relay based on the system state of the transformer and the insulation state, including: determining the system state based on the three-phase voltage data and the three-phase current data; An alarm module, used for controlling whether to issue an alarm signal based on the insulation state of the gas relay; The locking control module is used to determine to disconnect the locking relay to disconnect the outlet circuit when the system state is in the closed state and the insulation state is in the abnormal state; and to determine not to disconnect the locking relay to open the outlet circuit when the system state is in the started state.

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