A method and system for identifying latent faults of transformer protection in operation state

Abstract

The present invention provides a method for identifying potential faults of transformer protection in operation, which is used in a transformer substation including a main transformer and high and low voltage side busbars; the high voltage side busbar is connected to the main transformer via a high voltage side circuit breaker, and a high voltage side current transformer connected to a high voltage side protection device is provided on the line; the low voltage side busbar is connected to the main transformer via a low voltage side circuit breaker, and a low voltage side current transformer connected to a low voltage side protection device is provided on the line; the method comprises: after a fault occurs on the low voltage side busbar, detecting the presence of a fault current between the high voltage side busbar, the main transformer and the low voltage side busbar; if there is a fault current, identifying whether the high voltage side protection device, the high voltage side circuit breaker, the low voltage side protection device and the low voltage side circuit breaker are in operation and whether the operation is normal, and determining the type of potential fault of transformer protection based on the identification result. Implementation of the present invention can accurately identify potential faults of transformer protection in operation, which is not only low-cost but also time-saving and labor-saving.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer fault detection, and in particular to a method and system for identifying latent faults of transformer protection in an operating state. Background Art

[0002] Main transformer protection involves the main transformer itself and multi-side switches. The operating environment is complex, and there are many cases of incorrect protection operation. For example, in 2022, a fault occurred on the 10kV feeder of the #1 main transformer at a 220kV station. The main-second differential protection of the #1 main transformer tripped the three-side switches of the main transformer, and the main-first protection did not operate. Technical personnel went to the site for inspection and found that the insulation of the current loop cable of the 501 switch of the main-second protection was abnormal, resulting in no current sampling in the device. After investigation, it was found that the main-second protection of the #1 main transformer had an abnormal short circuit in the current loop cable, and the low-voltage current could not flow into the device. When a short circuit fault occurred outside the zone, the main transformer protection malfunctioned. For example, if the "transformer wiring method" in the internal configuration menu of a manufacturer's 110kV differential protection device is inconsistent with the main transformer and secondary circuit wiring, it is not easy to detect during low-load operation, and when a fault occurs outside the zone, it will cause the differential protection to malfunction.

[0003] However, there are many reasons for the malfunction of the main transformer, including faults in protection device components or settings, faults in the CT connected to the protection device, and faults in circuit breaker components. However, these faults that cause malfunctions can remain latent for a long time and are difficult to detect during normal operation.

[0004] Currently, there is a lack of effective solutions to troubleshoot the aforementioned latent faults, which can only be discovered through a large amount of manual searching after a power outage, which is not only costly but also inaccurate. Summary of the Invention

[0005] The technical problem to be solved by the embodiments of the present invention is to provide a method and system for identifying latent faults of transformer protection in an operating state, which can accurately identify latent faults of transformer protection in an operating state, is not only low-cost, but also saves time and effort.

[0006] In order to solve the above technical problems, an embodiment of the present invention provides a method for identifying latent faults of transformer protection in an operating state, which is used in a substation including a main transformer, a high-voltage busbar, and a low-voltage busbar; the high-voltage busbar is connected to the main transformer via a high-voltage circuit breaker, and a high-voltage current transformer connected to a high-voltage protection device is provided on the line connected to the main transformer; the low-voltage busbar is connected to the main transformer via a low-voltage circuit breaker, and a low-voltage current transformer connected to a low-voltage protection device is provided on the line connected to the main transformer; wherein the method comprises the following steps:

[0007] After a fault occurs on the low-voltage side busbar, detecting the presence of a fault current between the high-voltage side busbar, the main transformer and the low-voltage side busbar;

[0008] If a fault current is detected, the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device and the low-voltage side circuit breaker are all identified as to whether they are operating and whether the operation is normal, and based on the identification result, the type of latent fault of the transformer protection is determined; wherein, the latent fault type of the transformer protection is one of a fault in a component or set value of the high-voltage side protection device, a fault in a component or set value of the low-voltage side protection device, a fault in a low-voltage side current transformer and a fault in a component of the low-voltage side circuit breaker.

[0009] Wherein, if a fault current is detected, the steps of identifying whether the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device, and the low-voltage side circuit breaker are operating and whether the operations are normal, and determining the type of latent fault of the transformer protection based on the identification results specifically include:

[0010] After detecting the fault current, if it is detected that the high-voltage side protection device is actuated and malfunctioned, and it is detected that both the high-voltage side circuit breaker and the low-voltage side protection device are actuated and normal, it is determined that the latent fault type of the transformer protection is a fault in the high-voltage side protection device component or set value.

[0011] Wherein, if a fault current is detected, the step of identifying whether the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device, and the low-voltage side circuit breaker are operating and whether the operation is normal, and determining the type of latent fault of the transformer protection based on the identification result further specifically includes:

[0012] After detecting the fault current, if it is detected that the high-voltage side protection device, the high-voltage side circuit breaker and the low-voltage side protection device are all operating and normal, and if it is detected that the low-voltage side circuit breaker is not operating, it is determined that the latent fault type of the transformer protection is a fault in the low-voltage side circuit breaker component.

[0013] Wherein, if a fault current is detected, the step of identifying whether the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device, and the low-voltage side circuit breaker are operating and whether the operation is normal, and determining the type of latent fault of the transformer protection based on the identification result further includes:

[0014] After detecting the fault current, if it is detected that the high-voltage side protection device, the high-voltage side circuit breaker and the low-voltage side circuit breaker are all operating and normal, and if it is detected that the low-voltage side protection device is not operating, it is determined that the latent fault type of the transformer protection is a fault in the low-voltage side protection device component or constant.

[0015] There are two fault currents, including a high-voltage side fault current flowing from the high-voltage side bus to the main transformer and a low-voltage side fault current flowing from the main transformer to the low-voltage side bus.

[0016] Wherein, if a fault current is detected, the step of identifying whether the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device, and the low-voltage side circuit breaker are operating and whether the operation is normal, and determining the type of latent fault of the transformer protection based on the identification result further includes:

[0017] After detecting the fault current, if it is detected that the high-voltage side protection device and the high-voltage side circuit breaker are both operating and normal, and it is detected that the low-voltage side protection device and the low-voltage side circuit breaker are both not operating, it is determined that the latent fault type of the transformer protection is a fault in the low-voltage side current transformer.

[0018] There is only one fault current, which is the high-voltage side fault current flowing from the high-voltage side bus to the main transformer.

[0019] An embodiment of the present invention further provides a transformer protection latent fault identification system in operation, which cooperates with a substation including a main transformer, a high-voltage busbar, and a low-voltage busbar; the high-voltage busbar is connected to the main transformer via a high-voltage circuit breaker, and a high-voltage current transformer connected to a high-voltage protection device is provided on the line connected to the main transformer; the low-voltage busbar is connected to the main transformer via a low-voltage circuit breaker, and a low-voltage current transformer connected to a low-voltage protection device is provided on the line connected to the main transformer; wherein the system includes:

[0020] a fault current detection unit, configured to detect the presence of a fault current between the high-voltage side bus, the main transformer, and the low-voltage side bus after a fault occurs on the low-voltage side bus;

[0021] The latent fault locating unit is used to identify whether the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device and the low-voltage side circuit breaker are operating and whether the operation is normal if a fault current is detected, and determine the type of latent fault of the transformer protection based on the identification result; wherein the latent fault type of the transformer protection is one of a fault in a component or set value of the high-voltage side protection device, a fault in a component or set value of the low-voltage side protection device, a fault in a low-voltage side current transformer and a fault in a component of the low-voltage side circuit breaker.

[0022] Wherein, the latent fault locating unit includes:

[0023] A first fault locating module is configured to, after detecting a fault current, determine that the type of the transformer protection latent fault is a fault in a component or a setting of the high-voltage side protection device if it is detected that the high-voltage side protection device is actuated and malfunctions, and if it is detected that both the high-voltage side circuit breaker and the low-voltage side protection device are actuated and functioning normally;

[0024] A second fault locating module is configured to, after detecting a fault current, determine that the type of the transformer protection latent fault is a fault in a low-voltage side circuit breaker component if it is detected that the high-voltage side protection device, the high-voltage side circuit breaker, and the low-voltage side protection device are all operating and normal, and if it is detected that the low-voltage side circuit breaker is not operating;

[0025] a third fault locating module, configured to, after detecting a fault current, determine that the type of the transformer protection latent fault is a fault in a low-voltage side protection device component or a set value if it is detected that the high-voltage side protection device, the high-voltage side circuit breaker, and the low-voltage side circuit breaker are all operating and normal, and if it is detected that the low-voltage side protection device is not operating;

[0026] The fourth fault locating module is used to determine that the latent fault type of the transformer protection is a fault in the low-voltage side current transformer after detecting a fault current, if it is detected that the high-voltage side protection device and the high-voltage side circuit breaker are both operating and normal, and if it is detected that the low-voltage side protection device and the low-voltage side circuit breaker are both not operating.

[0027] The implementation of the embodiments of the present invention has the following beneficial effects:

[0028] After a fault occurs in a substation, the present invention identifies whether a fault current is present, and identifies whether the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device and the low-voltage side circuit breaker are operating and whether the operation is normal. The type of latent fault of the transformer protection is determined through a logical relationship, thereby accurately identifying the latent fault of the transformer protection in the operating state, which is not only low-cost but also time-saving and labor-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying any creative work, other drawings obtained based on these drawings still fall within the scope of the present invention.

[0030] Figure 1 A flowchart of a method for identifying potential faults of transformer protection in an operating state provided by an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of the local structural connection of a substation in a method for identifying potential faults of transformer protection in an operating state provided by an embodiment of the present invention;

[0032] Figure 3 A logical relationship judgment diagram of transformer protection latent fault types in a method for identifying transformer protection latent faults in an operating state provided by an embodiment of the present invention;

[0033] Figure 4 A schematic structural diagram of a transformer protection latent fault identification system in operation provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be described in further detail below with reference to the accompanying drawings.

[0035] like Figure 1 As shown in FIG, a method for identifying potential faults of transformer protection in operation is provided in an embodiment of the present invention, which is used in a substation including a main transformer, a high-voltage bus and a low-voltage bus. Figure 2 shown; in Figure 2 In the embodiment, the high-voltage side busbar is connected to the main transformer via the high-voltage side circuit breaker DL1, and the line connected to the main transformer is provided with a high-voltage side current transformer CT1 connected to a high-voltage side protection device (not shown); the low-voltage side busbar is connected to the main transformer via the low-voltage side circuit breaker DL2, and the line connected to the main transformer is provided with a low-voltage side current transformer CT2 connected to a low-voltage side protection device (not shown); wherein the method comprises the following steps:

[0036] Step S1: After a fault occurs on the low-voltage side busbar, detecting the presence of a fault current between the high-voltage side busbar, the main transformer, and the low-voltage side busbar;

[0037] Step S2: If a fault current is detected, whether the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device, and the low-voltage side circuit breaker are operating and whether the operation is normal are all identified, and based on the identification result, the type of latent fault of the transformer protection is determined; wherein the latent fault type of the transformer protection is one of a fault in a component or a set value of the high-voltage side protection device, a fault in a component or a set value of the low-voltage side protection device, a fault in a low-voltage side current transformer, and a fault in a component of the low-voltage side circuit breaker.

[0038] The specific process is as follows: in step S1, before the low-voltage busbar fails, there is a load current between the high-voltage busbar, the main transformer, and the low-voltage busbar, including the high-voltage load current flowing from the high-voltage busbar to the main transformer and the low-voltage load current flowing from the main transformer to the low-voltage busbar, which are respectively identified by the high-voltage side current transformer CT1 and the low-voltage side current transformer CT2. Once the low-voltage busbar fails, there will be a fault current between the high-voltage busbar, the main transformer, and the low-voltage busbar, and its flow direction is consistent with the load current flow direction. Therefore, it is possible to determine whether a substation fault has occurred by detecting the presence of fault current between the high-voltage busbar, the main transformer, and the low-voltage busbar.

[0039] It should be noted that when the current transformer CT2 on the low-voltage side fails, the fault current on the low-voltage side cannot be collected, that is, there is no current on the low-voltage side.

[0040] In step S2, after the fault current is identified, the operation of the high and low voltage side protection devices and the high and low voltage side circuit breakers and whether the operation is normal are identified, and the type of potential fault of the transformer protection is determined through logical relationships.

[0041] like Figure 3 As shown, the specific logical relationship is as follows:

[0042] (1) After detecting the fault current, if it is detected that the high-voltage side protection device is actuated and malfunctioned, and if it is detected that the high-voltage side circuit breaker DL1 and the low-voltage side protection device are both actuated and normal, it is determined that the transformer protection latent fault type is a fault in the high-voltage side protection device element or setting value; at this time, there are two fault currents and the flow direction is consistent with the high- and low-voltage side load current flow direction in step S1, including the high-voltage side fault current i1 flowing from the high-voltage side bus to the main transformer and the low-voltage fault current i2 flowing from the main transformer to the low-voltage side bus;

[0043] (2) After detecting the fault current, if it is detected that the high-voltage side protection device, the high-voltage side circuit breaker DL1 and the low-voltage side protection device are all operating and normal, and if it is detected that the low-voltage side circuit breaker DL2 is not operating, it is determined that the transformer protection latent fault type is a fault in the low-voltage side circuit breaker DL2 component; at this time, there are two fault currents and the flow direction is consistent with the high- and low-voltage side load current flow direction in step S1, including the high-voltage side fault current i1 flowing from the high-voltage side bus to the main transformer and the low-voltage fault current i2 flowing from the main transformer to the low-voltage side bus;

[0044] (3) After detecting the fault current, if it is detected that the high-voltage side protection device, the high-voltage side circuit breaker DL1 and the low-voltage side circuit breaker DL2 are all operating and normal, and if it is detected that the low-voltage side protection device is not operating, it is determined that the type of latent fault of the transformer protection is a fault in the low-voltage side protection device element or the setting value; at this time, there are two fault currents and the flow direction is consistent with the flow direction of the high and low voltage side load currents in step S1, including the high-voltage side fault current i1 flowing from the high-voltage side bus to the main transformer and the low-voltage fault current i2 flowing from the main transformer to the low-voltage side bus;

[0045] (4) After detecting the fault current, if it is detected that the high-voltage side protection device and the high-voltage side circuit breaker DL1 are both operative and normal, and if it is detected that the low-voltage side protection device and the low-voltage side circuit breaker DL2 are both inoperative, it is determined that the transformer protection latent fault type is a fault in the low-voltage side current transformer CT2; at this time, there is only one fault current and its flow direction is consistent with the high-voltage side load current flow direction in step S1, which is the high-voltage side fault current i1 flowing from the high-voltage side bus to the main transformer, and there is no current on the low-voltage side, that is, the low-voltage fault current i2 = 0.

[0046] like Figure 4 As shown, in an embodiment of the present invention, a transformer protection latent fault identification system in operation is provided, which cooperates with a substation including a main transformer, a high-voltage busbar, and a low-voltage busbar; the high-voltage busbar is connected to the main transformer via a high-voltage side circuit breaker, and a high-voltage side current transformer connected to a high-voltage side protection device is provided on the line connected to the main transformer; the low-voltage side busbar is connected to the main transformer via a low-voltage side circuit breaker, and a low-voltage side current transformer connected to a low-voltage side protection device is provided on the line connected to the main transformer; wherein the system includes:

[0047] The fault current detection unit 110 is used to detect the presence of a fault current between the high-voltage side bus, the main transformer and the low-voltage side bus after a fault occurs on the low-voltage side bus;

[0048] The latent fault locating unit 120 is used to identify whether the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device and the low-voltage side circuit breaker are operating and whether the operation is normal if a fault current is detected, and determine the type of latent fault of the transformer protection based on the identification result; wherein the latent fault type of the transformer protection is one of a fault in a component or set value of the high-voltage side protection device, a fault in a component or set value of the low-voltage side protection device, a fault in a low-voltage side current transformer and a fault in a component of the low-voltage side circuit breaker.

[0049] The latent fault location unit 120 includes:

[0050] A first fault locating module is configured to, after detecting a fault current, determine that the type of the transformer protection latent fault is a fault in a component or a setting of the high-voltage side protection device if it is detected that the high-voltage side protection device is actuated and malfunctions, and if it is detected that both the high-voltage side circuit breaker and the low-voltage side protection device are actuated and functioning normally;

[0051] A second fault locating module is configured to, after detecting a fault current, determine that the type of the transformer protection latent fault is a fault in a low-voltage side circuit breaker component if it is detected that the high-voltage side protection device, the high-voltage side circuit breaker, and the low-voltage side protection device are all operating and normal, and if it is detected that the low-voltage side circuit breaker is not operating;

[0052] a third fault locating module, configured to, after detecting a fault current, determine that the type of the transformer protection latent fault is a fault in a low-voltage side protection device component or a set value if it is detected that the high-voltage side protection device, the high-voltage side circuit breaker, and the low-voltage side circuit breaker are all operating and normal, and if it is detected that the low-voltage side protection device is not operating;

[0053] The fourth fault locating module is used to determine that the latent fault type of the transformer protection is a fault in the low-voltage side current transformer after detecting a fault current, if it is detected that the high-voltage side protection device and the high-voltage side circuit breaker are both operating and normal, and if it is detected that the low-voltage side protection device and the low-voltage side circuit breaker are both not operating.

[0054] The implementation of the embodiments of the present invention has the following beneficial effects:

[0055] After a fault occurs in a substation, the present invention identifies whether a fault current is present, and identifies whether the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device and the low-voltage side circuit breaker are operating and whether the operation is normal. The type of latent fault of the transformer protection is determined through a logical relationship, thereby accurately identifying the latent fault of the transformer protection in the operating state, which is not only low-cost but also time-saving and labor-saving.

[0056] It is worth noting that in the above system embodiment, the various system units included are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of the various functional units are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of the present invention.

[0057] Those skilled in the art will understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc.

[0058] The above disclosure is merely a preferred embodiment of the present invention and certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for identifying latent faults of transformer protection in operation, for use in a substation comprising a main transformer, a high-voltage busbar, and a low-voltage busbar; the high-voltage busbar is connected to the main transformer via a high-voltage circuit breaker, and a high-voltage current transformer connected to a high-voltage protection device is provided on the line connected to the main transformer; the low-voltage busbar is connected to the main transformer via a low-voltage circuit breaker, and a low-voltage current transformer connected to a low-voltage protection device is provided on the line connected to the main transformer; and the method is characterized in that: The method comprises the following steps: After a fault occurs on the low-voltage side busbar, detecting the presence of a fault current between the high-voltage side busbar, the main transformer and the low-voltage side busbar; If a fault current is detected, the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device and the low-voltage side circuit breaker are all identified as to whether they are operating and whether the operation is normal, and based on the identification result, the type of latent fault of the transformer protection is determined; wherein, the latent fault type of the transformer protection is one of a fault in a component or set value of the high-voltage side protection device, a fault in a component or set value of the low-voltage side protection device, a fault in a low-voltage side current transformer and a fault in a component of the low-voltage side circuit breaker.

2. The method for identifying potential faults of transformer protection in operation state according to claim 1, characterized in that: If a fault current is detected, identifying whether the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device, and the low-voltage side circuit breaker are operating and whether the operations are normal, and determining the type of potential fault of the transformer protection based on the identification results specifically includes: After detecting the fault current, if it is detected that the high-voltage side protection device is actuated and malfunctioned, and it is detected that both the high-voltage side circuit breaker and the low-voltage side protection device are actuated and normal, it is determined that the latent fault type of the transformer protection is a fault in the high-voltage side protection device component or set value.

3. The method for identifying potential faults of transformer protection in an operating state according to claim 1, wherein: If a fault current is detected, identifying whether the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device, and the low-voltage side circuit breaker are operating and whether the operations are normal, and determining the type of potential fault of the transformer protection based on the identification result further specifically includes: After detecting the fault current, if it is detected that the high-voltage side protection device, the high-voltage side circuit breaker and the low-voltage side protection device are all operating and normal, and if it is detected that the low-voltage side circuit breaker is not operating, it is determined that the latent fault type of the transformer protection is a fault in the low-voltage side circuit breaker component.

4. The method for identifying potential faults of transformer protection in an operating state according to claim 1, wherein: If a fault current is detected, the step of identifying whether the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device, and the low-voltage side circuit breaker are operating and whether the operations are normal, and determining the type of potential fault of the transformer protection based on the identification result further includes: After detecting the fault current, if it is detected that the high-voltage side protection device, the high-voltage side circuit breaker and the low-voltage side circuit breaker are all operating and normal, and if it is detected that the low-voltage side protection device is not operating, it is determined that the latent fault type of the transformer protection is a fault in the low-voltage side protection device component or constant.

5. The method for identifying latent faults of transformer protection in an operating state according to any one of claims 2 to 4, characterized in that: There are two fault currents, including a high-voltage side fault current flowing from the high-voltage side bus to the main transformer and a low-voltage side fault current flowing from the main transformer to the low-voltage side bus.

6. The method for identifying potential faults of transformer protection in operation state according to claim 1, characterized in that: If a fault current is detected, the step of identifying whether the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device, and the low-voltage side circuit breaker are operating and whether the operations are normal, and determining the type of potential fault of the transformer protection based on the identification result further includes: After detecting the fault current, if it is detected that the high-voltage side protection device and the high-voltage side circuit breaker are both operating and normal, and it is detected that the low-voltage side protection device and the low-voltage side circuit breaker are both not operating, it is determined that the latent fault type of the transformer protection is a fault in the low-voltage side current transformer.

7. The method for identifying latent faults of transformer protection in operation state according to claim 6, characterized in that: There is only one fault current, which is the high-voltage side fault current flowing from the high-voltage side bus to the main transformer.

8. A transformer protection latent fault identification system in operation, which cooperates with a substation including a main transformer, a high-voltage side busbar and a low-voltage side busbar; the high-voltage side busbar is connected to the main transformer through a high-voltage side circuit breaker, and a high-voltage side current transformer connected to a high-voltage side protection device is provided on the line connected to the main transformer; the low-voltage side busbar is connected to the main transformer through a low-voltage side circuit breaker, and a low-voltage side current transformer connected to a low-voltage side protection device is provided on the line connected to the main transformer; characterized in that, The system comprises: a fault current detection unit, configured to detect the presence of a fault current between the high-voltage side bus, the main transformer, and the low-voltage side bus after a fault occurs on the low-voltage side bus; The latent fault locating unit is used to identify whether the high-voltage side protection device, the high-voltage side circuit breaker, the low-voltage side protection device and the low-voltage side circuit breaker are operating and whether the operation is normal if a fault current is detected, and determine the type of latent fault of the transformer protection based on the identification result; wherein the latent fault type of the transformer protection is one of a fault in a component or set value of the high-voltage side protection device, a fault in a component or set value of the low-voltage side protection device, a fault in a low-voltage side current transformer and a fault in a component of the low-voltage side circuit breaker.

9. The transformer protection latent fault identification system in operation state according to claim 8, characterized in that: The latent fault locating unit includes: A first fault locating module is configured to, after detecting a fault current, determine that the type of the transformer protection latent fault is a fault in a component or a setting of the high-voltage side protection device if it is detected that the high-voltage side protection device is actuated and malfunctions, and if it is detected that both the high-voltage side circuit breaker and the low-voltage side protection device are actuated and functioning normally; A second fault locating module is configured to, after detecting a fault current, determine that the type of the transformer protection latent fault is a fault in a low-voltage side circuit breaker component if it is detected that the high-voltage side protection device, the high-voltage side circuit breaker, and the low-voltage side protection device are all operating and normal, and if it is detected that the low-voltage side circuit breaker is not operating; a third fault locating module, configured to, after detecting a fault current, determine that the type of the transformer protection latent fault is a fault in a low-voltage side protection device component or a set value if it is detected that the high-voltage side protection device, the high-voltage side circuit breaker, and the low-voltage side circuit breaker are all operating and normal, and if it is detected that the low-voltage side protection device is not operating; The fourth fault locating module is used to determine that the latent fault type of the transformer protection is a fault in the low-voltage side current transformer after detecting a fault current, if it is detected that the high-voltage side protection device and the high-voltage side circuit breaker are both operating and normal, and if it is detected that the low-voltage side protection device and the low-voltage side circuit breaker are both not operating.

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