PT fuse slow melting judgment method based on split-phase comparison, medium and electronic equipment

Abstract

The invention relates to the technical field of generator excitation systems, in particular to a PT fuse slow melting judgment method based on phase-splitting comparison, a medium and electronic equipment. The PT fuse slow melting detection comprises the following steps: comparing a PT signal three-phase voltage amplitude accessed by an online operation control channel with a PT signal three-phase voltage amplitude accessed by a standby control channel one by one; and if any phase voltage deviation reaches a phase voltage deviation threshold value and the duration exceeds a preset duration, judging that the PT with a relatively low phase voltage amplitude has a fuse slow-melting fault, and triggering a PT fuse slow-melting alarm. The method is more sensitive to the single-phase PT fuse slow-melting fault of the excitation system, the fault can be rapidly and accurately detected when the PT fuse slow-melting fault of the excitation system occurs, and measures can be conveniently and timely taken for treatment.

Description

Technical Field

[0001] The invention relates to the technical field of generator excitation systems, and in particular to a PT insurance slow-blow judgment method based on phase comparison, a medium and an electronic device. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] The excitation system is an important control device for the generator set. The constant machine end voltage mode is its default operation mode. In order to ensure the reliability of voltage measurement, the general excitation system is connected to two PT signals. At present, most of the excitation regulators of the excitation system adopt the classic dual-channel architecture, one control channel is online control (i.e., online operation control channel), and the other control channel is standby (i.e., standby control channel). The two PT signals are connected to two control channels respectively. After one PT signal fails, normal control can be restored by channel switching, and the constant machine end voltage mode can be maintained.

[0004] PT line break generally refers to the primary line break, which is the most common PT fault in the excitation system. Single-phase primary line break will cause the 2-phase voltage amplitude to be halved, and the excitation system will be forced to excite incorrectly due to the sudden drop in the voltage measurement value. Figure 1 As shown, the A-phase conductor of the PT primary is disconnected, so the A-phase signal is not connected to the PT primary, resulting in abnormal amplitude and phase of Ua' and Uc' of the PT secondary (amplitude is halved, phase overlaps). The PT line break fault occurs instantaneously, without a slow change process. For this fault, the fault is usually judged by comparing the three-phase voltage amplitudes. If the difference between the maximum and minimum phase voltages is too large, the PT line is judged to be broken. If the fault channel where the PT line break occurs is the online operation control channel, the standby control channel is immediately switched to online control, and the fault channel is switched to constant excitation current mode, with the excitation current as the control object. If a PT line break fault occurs in the online operation control channel, and a PT line break fault also occurs in the standby control channel, the online operation control channel remains in the online control state, and only the operation mode is switched from constant machine end voltage mode to constant excitation current mode.

[0005] Compared with PT line break, the fault phenomenon of PT fuse slow melting is not obvious. PT fuse slow melting is a slow-changing process. Figure 2 As shown in the figure, when the A-phase fuse of the PT secondary side starts to heat up for some reason, the resistance R fa The resistance value increases as the temperature rises, and the voltage divider U of the fuse in the series circuit fa If the secondary A phase voltage Ua of the PT remains unchanged, the voltage Ua' output to the analog signal modulation module decreases, causing the voltage signal entering the control channel to decrease. fabecomes larger, and the heat generation power is I 2 R fa If the PT secondary current Ia remains unchanged, the fuse heat will increase with R fa The resistance value increases, causing the fuse temperature to rise further. fa The voltage signal amplitude output to the control channel is further increased, and the voltage signal amplitude output to the control channel is further reduced. It can be seen that the slow melting of the PT fuse is a slow-changing fault that gradually worsens, and it is a gradual process. The slow melting of the PT fuse causes the voltage signal amplitude to be low, increases the voltage measurement error, and leads to inaccurate calculation results of active power, reactive power and angular velocity, which has a serious negative impact on excitation control.

[0006] The PT fuse slow-blow fault may occur in a certain phase or in all three phases at the same time. This type of fault cannot be detected by comparing the PT three-phase voltage measurement values. This is because when a single-phase PT fuse slow-blows, the deviation between the maximum and minimum phase voltages is not as large as when a PT line break fault occurs. When a three-phase PT fuse slow-blows, the difference in the three-phase voltage amplitudes is almost 0.

[0007] The current PT insurance slow-fuse fault detection usually directly compares the three-phase voltage averages of the two PT signals. For control channel 1 (i.e., the online operation control channel), the three-phase voltage average measured by the excitation PT is: V abc1 =(V a1 +V b1 +V c1 ) / 3; here V a1 、V b1 、V c1 is the three-phase voltage value of the excitation PT measured by control channel 1, V abc1 is the average three-phase voltage calculated by control channel 1. The average three-phase voltage of the instrument PT measured by control channel 2 (i.e., the standby control channel) is: V abc2 =(V a2 +V b2 +V c2 ) / 3; here V a2 、V b2 、V c2 It is the instrument PT three-phase voltage value measured by control channel 2, V abc2 is the average value of the three-phase voltage calculated by control channel 2. If V abc2 -V abc1 >0.05U n, where Un is the rated value of the stator voltage, and if the fault phenomenon lasts for more than 5 seconds, the control channel 1 can determine that the excitation PT has a PT fuse slow-blow fault. The biggest problem with this detection method is that it is not sensitive to single-phase PT fuse slow-blow faults. It will only trigger an alarm when the single-phase voltage deviation reaches 3 times the fault threshold, which is not conducive to early detection of single-phase fuse faults and is likely to have a serious negative impact on excitation control. In view of the above defects, the present invention has made improvements. Summary of the invention

[0008] In order to overcome the shortcomings of the background technology, the present invention provides a PT fuse slow-blow judgment method, medium and electronic equipment based on phase comparison. The method is more sensitive to the single-phase PT fuse slow-blow fault of the excitation system, and can quickly and accurately detect the fault when the PT fuse slow-blow fault occurs in the excitation system, so that timely measures can be taken to deal with it.

[0009] To achieve the above object, the present invention provides a PT fuse slow-blow judgment method based on phase comparison, the method uses PT fuse slow-blow detection for judgment, and the PT fuse slow-blow detection includes:

[0010] Compare the three-phase voltage amplitude of the PT signal connected to the online operation control channel with the three-phase voltage amplitude of the PT signal connected to the standby control channel phase by phase;

[0011] If any phase voltage deviation reaches the phase voltage deviation threshold and lasts for more than a preset time, it is determined that the PT with a lower phase voltage amplitude in that phase has a slow-blow fuse fault, and the PT slow-blow fuse alarm is triggered.

[0012] Further,

[0013] The PT insurance slow-fuse detection sets the start conditions, and the start conditions include:

[0014] Determine whether the average value of the three-phase voltage amplitude output by the PT is greater than the PT insurance slow-fuse detection start threshold;

[0015] If the average value of the three-phase voltage amplitude output by the PT is greater than the PT insurance slow-blow detection start threshold, the PT insurance slow-blow detection is started.

[0016] Further,

[0017] The PT insurance slow-blow detection start threshold is set to 0.5Un, where Un is the stator voltage rated value.

[0018] Further,

[0019] The PT insurance slow-blow detection also includes:

[0020] The online operation control channel obtains the three-phase voltage amplitude of the PT signal connected to the standby control channel through communication.

[0021] Further,

[0022] The phase voltage deviation threshold is set to 0.05Un, the preset time length is set to 5 seconds, and Un is the stator voltage rated value.

[0023] Further,

[0024] The PT insurance slow-blow detection also includes:

[0025] The three-phase voltage amplitude of the PT signal connected to the online operation control channel is compared phase by phase with the three-phase voltage amplitude of the PT signal connected to the standby control channel in a query cycle of 4 milliseconds.

[0026] Further,

[0027] When comparing the three-phase voltage amplitude of the PT signal connected to the online operation control channel with the three-phase voltage amplitude of the PT signal connected to the standby control channel phase by phase, if the voltage deviation of any phase reaches 0.05Un, the PT insurance slow-blow fault counter of the phase is incremented, and it is determined whether the PT insurance slow-blow fault counter of the phase reaches 1250;

[0028] If the phase PT fuse slow-blow fault counter reaches 1250, the phase PT fuse slow-blow flag is set;

[0029] If the PT fuse slow-blow mark appears in any phase, the PT fuse slow-blow total mark is set and the PT fuse slow-blow alarm is triggered.

[0030] Further,

[0031] When comparing the three-phase voltage amplitude of the PT signal connected to the online operation control channel with the three-phase voltage amplitude of the PT signal connected to the standby control channel phase by phase, if the voltage deviation of any phase does not reach 0.05Un, the slow-blow fault counter of the PT fuse of that phase is set to 0 and the slow-blow flag of the PT fuse of that phase is cleared.

[0032] Based on the same inventive concept, the present invention also provides a computer-readable storage medium storing one or more programs. When the one or more programs are executed, the aforementioned PT fuse slow-blow judgment method based on phase comparison can be implemented.

[0033] Based on the same inventive concept, the present invention also provides an electronic device, including a processor, a communication interface, a computer-readable storage medium as described above, and a communication bus; wherein the processor, the communication interface, and the computer-readable storage medium communicate with each other via the communication bus; and the processor is used to execute the program stored in the computer-readable storage medium.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention makes a PT fuse slow-blow judgment based on phase-by-phase comparison, is more sensitive to a single-phase PT fuse slow-blow fault in an excitation system, can quickly and accurately detect a fault when a PT fuse slow-blow fault occurs in the excitation system, and can facilitate timely taking measures to handle the fault.

[0036] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings.

[0037] The present invention will be further described below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0039] Figure 1 A schematic diagram of the A-phase PT disconnection in the excitation system;

[0040] Figure 2 A schematic diagram of a Y / Δ-connected PT and its fuse according to an embodiment of the present invention;

[0041] Figure 3 A schematic diagram of a flow chart of a method for determining a slow-blow PT fuse based on phase comparison according to an embodiment of the present invention;

[0042] Figure 4 A block diagram of an excitation system according to an embodiment of the present invention;

[0043] Figure 5 A schematic diagram of a process for phase voltage deviation detection according to an embodiment of the present invention;

[0044] Figure 6 A schematic diagram of a process for determining a slow-blow PT fuse based on phase comparison according to an embodiment of the present invention;

[0045] Figure 7 The figure is a schematic diagram of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the implementation of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all the embodiments. 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.

[0047] like Figures 2 to 7 As shown, this embodiment discloses a PT fuse slow-blow judgment method based on phase comparison, the method uses PT fuse slow-blow detection for judgment, and the PT fuse slow-blow detection includes:

[0048] Compare the three-phase voltage amplitude of the PT signal connected to the online operation control channel with the three-phase voltage amplitude of the PT signal connected to the standby control channel phase by phase;

[0049] If any phase voltage deviation reaches the phase voltage deviation threshold and lasts for more than a preset time, it is determined that the PT with a lower phase voltage amplitude in that phase has a slow-blow fuse fault, and the PT slow-blow fuse alarm is triggered.

[0050] The above technical solution is more sensitive to the slow-blow fault of the single-phase PT fuse in the excitation system, and can quickly and accurately detect the fault when the slow-blow fault of the PT fuse occurs in the excitation system, thereby better ensuring the normal operation of the excitation system.

[0051] The above-mentioned method for judging whether a PT fuse is slow-blow based on phase comparison will be further explained below.

[0052] In order to better judge the slow-blow of the PT fuse, this embodiment sets a start condition for the slow-blow detection of the PT fuse, and the start condition includes:

[0053] Determine whether the average value of the three-phase voltage amplitude output by the PT is greater than the PT insurance slow-fuse detection start threshold;

[0054] If the average value of the three-phase voltage amplitude output by the PT is greater than the PT insurance slow-blow detection start threshold, the PT insurance slow-blow detection is started.

[0055] In some embodiments, the PT insurance slow-blow detection start threshold is set to 0.5Un, where Un is the stator voltage rating (i.e. the generator rated stator voltage). When it is determined that the three-phase voltage average value is greater than 0.5Un, the PT insurance slow-blow detection is started for judgment.

[0056] When the generator is connected to the grid, the allowable voltage setting range is 0.7~1.1Un, and the allowable setting range when no-load is generally 0.1~1.15Un. When the generator terminal voltage reaches 0.3Un or above, the PT signal is relatively stable, and a smaller absolute deviation will not produce a larger relative deviation. For example, the relative deviation of a deviation of 0.05Un is 50% (the ratio of deviation to amplitude) when the terminal voltage is 0.1Un, and the relative deviation is 10% when the terminal voltage is 0.3Un. Therefore, most of the various limiting protections of the excitation system will not be activated until the terminal voltage reaches a relatively high value, avoiding the false operation of the limiting protection based on the relative deviation as the criterion. The slow melting of the PT insurance is a slow-changing process with relatively low harm. Therefore, the PT insurance slow melting detection starting threshold of this embodiment is selected based on experience. A higher starting voltage of 0.5Un.

[0057] In some embodiments, the PT fuse slow blow detection also includes: the online operation control channel obtains the three-phase voltage amplitude of the PT signal connected to the backup control channel through communication.

[0058] like Figure 4 As shown, in order to ensure disturbance-free switching, the two control channels of the excitation regulator of this embodiment are interconnected through a communication channel for exchanging control information. In order to facilitate the detection of slow-blow PT fuses, this embodiment adds the three-phase voltage amplitude to the exchanged control information, so that the online operation control channel can obtain the three-phase voltage amplitude of the PT signal connected to the standby control channel through communication. In specific implementation, the communication methods between control channels mainly include optical fiber communication, Ethernet communication, serial communication, CAN communication, etc., as long as the data exchange requirements are met.

[0059] In some embodiments, the phase voltage deviation threshold is set to 0.05Un, the preset time length is set to 5 seconds, and Un is the stator voltage rating (i.e., the rated stator voltage of the generator). In this embodiment, the control channel compares the phase voltage amplitude measured by the current channel (i.e., the online operation control channel) and the source control channel (i.e., the standby control channel) phase by phase in the periodic task. If any phase voltage deviation reaches 0.05Un and lasts for more than 5 seconds, it is determined that the PT with the lower phase voltage amplitude has a slow fuse failure, and the PT slow fuse alarm is triggered.

[0060] In some embodiments, the PT fuse slow-blow detection further includes: comparing the three-phase voltage amplitude of the PT signal connected to the online operation control channel with the three-phase voltage amplitude of the PT signal connected to the standby control channel phase by phase with a query period of 4 milliseconds. The query period of the periodic task in this embodiment is preferably 4 milliseconds, which can ensure a higher query frequency and is conducive to more timely discovery of PT fuse slow-blow faults.

[0061] The phase voltage deviation detection and PT fuse slow-blow judgment of this embodiment will be further described below.

[0062] Taking control channel 1 (i.e., online operation control channel) as an example, the excitation PT signal is measured by itself to obtain V a1 、V b1 、V c1 The three phase voltage amplitudes are obtained through communication, and the instrument PT three-phase voltage measurement value V is measured by control channel 2 (i.e., standby control channel). a2 、V b2 、V c2 .

[0063] In the 4 millisecond cycle task, the A phase voltage of the two PTs is first compared. If V a2 -V a1 >0.05U n , increment the A-phase PT fuse slow-blow fault counter, otherwise set the A-phase PT fuse slow-blow fault counter to 0 and clear the A-phase PT fuse slow-blow flag. If the A-phase PT fuse slow-blow fault counter reaches 1250, set the A-phase PT fuse slow-blow flag.

[0064] Then use the same method to detect the slow-blow PT fuse of phase B, V b2 -V b1 >0.05U n , increment the B-phase PT fuse slow blow fault counter, otherwise set the B-phase PT fuse slow blow fault counter to 0 and clear the B-phase PT fuse slow blow flag. If the B-phase PT fuse slow blow fault counter reaches 1250, set the B-phase PT fuse slow blow flag.

[0065] Finally, check the slow-melting PT fuse of phase C. c2 -V c1 >0.05U n , increment the C-phase PT fuse slow-blow fault counter, otherwise set the C-phase PT fuse slow-blow fault counter to 0 and clear the C-phase PT fuse slow-blow flag. If the C-phase PT fuse slow-blow fault counter reaches 1250, set the C-phase PT fuse slow-blow flag.

[0066] During the detection process, if the PT fuse slow-blow mark appears in any phase, the PT fuse slow-blow total mark will be set and the PT fuse slow-blow alarm will be triggered.

[0067] The slow-blow PT fuse in this embodiment refers to the slow-blow fuse of the PT secondary side. The voltage of the PT secondary side corresponding to the rated voltage of the generator terminal is generally 100V or 105V. The PT secondary side is generally equipped with a fuse. The PT primary side is directly connected to the generator set terminal, and the rated voltage of the terminal of large and medium-sized generator sets may reach 10kV or even 22kV, so the PT primary side is generally not suitable for installing a fuse. The reasons for the slow-blow of the PT fuse are generally: poor contact may increase the contact resistance of the fuse, or the fuse parameters do not match the signal current, causing the fuse to heat up. The slow-blow failure of the PT fuse causes the voltage signal amplitude to be low, increases the voltage measurement error, and causes inaccurate calculation results of active power, reactive power and angular velocity, which has a serious negative impact on excitation control.

[0068] In this embodiment, the excitation PT and the instrument PT are exactly the same, and the primary sides of both are connected to the generator end, but the secondary side of the excitation PT is connected to the control channel 1 (i.e., the online operation control channel), and the secondary side of the instrument PT is connected to the control channel 2 (i.e., the standby control channel).

[0069] The technical advantages of the PT fuse slow-blow judgment method based on phase comparison of the present invention will be further illustrated by comparison below.

[0070] The measured value of the three-phase voltage of the excitation PT is V a1 、V b1 and V c1 , the average value of three-phase voltage V abc1 =(V a1 +V b1 +V c1 ) / 3; the instrument uses PT three-phase voltage measurement value is V a2 、V b2 and V c2 , the average value of three-phase voltage V abc2 =(V a2 +V b2 +V c2 ) / 3.

[0071] The current conventional PT insurance slow blow is relatively V abc1 、V abc2 If the three-phase fuses of the secondary side of the instrument PT are abnormal at the same time, and the deviation of the three-phase voltage average value of the excitation PT reaches the fault threshold,

[0072] V abc1 -V abc2 ≥0.05U n

[0073] V a1 -V a2 ≈0.05U n

[0074] Vb1 -V b2 ≈0.05U n

[0075] V c1 -V c2 ≈0.05U n

[0076] Here Un is the rated value of the stator voltage (i.e. the rated stator voltage of the generator).

[0077] If the single-phase fuse of the secondary side of the instrument PT is abnormal, it is assumed that phase A is abnormal, and the deviation of the three-phase voltage average value of the excitation PT reaches the fault threshold,

[0078] V abc1 -V abc2 ≥0.05U n

[0079] V a1 -V a2 ≈0.15U n

[0080] V b1 -V b2 ≈0

[0081] V c1 -V c2 ≈0

[0082] If the method based on phase comparison in the embodiment of the present invention is adopted, that is, V a1 With V a2 Compare, V b1 With V b2 Compare, V c1 With V c2 Compare:

[0083] If the three-phase fuses of the instrument PT secondary side are abnormal at the same time, and the phase voltage deviation with the three-phase voltage amplitude of the excitation PT reaches the fault threshold,

[0084] V a1 -V a2 ≈0.05U n

[0085] V b1 -V b2 ≈0.05U n

[0086] V c1 -V c2 ≈0.05U n

[0087] If the instrument PT secondary single-phase fuse is abnormal, here it is assumed that phase A is abnormal, and the phase voltage deviation with the excitation PT three-phase voltage amplitude reaches the fault threshold,

[0088] V a1 -V a2 ≈0.05U n

[0089] V b1 -V b2 ≈0

[0090] V c1 -V c2 ≈0

[0091] The time required for the phase voltage amplitude deviation of the 2-way PT to change from 0 to 0.05Un is much shorter than the time required for the phase voltage amplitude deviation to change from 0 to 0.15Un. It can be seen that the phase comparison can detect the fault as early as possible when a single-phase fuse fails.

[0092] In summary, the present invention adopts the above-mentioned PT fuse slow-blow judgment method based on phase comparison for detection and judgment, which is more sensitive to the single-phase PT fuse slow-blow fault of the excitation system, and can quickly and accurately detect the fault when the PT fuse slow-blow fault occurs in the excitation system. If it is judged that the PT fuse slow-blow fault occurs in the online operation control channel, it is generally necessary to switch the control channel in time to avoid the impact of the fault. At the same time, the faulty channel needs to switch the operation mode to a constant excitation current mode with the excitation current as the control object.

[0093] Based on the same inventive concept, an embodiment of the present invention further provides a computer-readable storage medium storing one or more programs. When the one or more programs are executed, the aforementioned PT fuse slow-blow judgment method based on phase comparison can be implemented.

[0094] Based on the same inventive concept, an embodiment of the present invention also provides an electronic device, including a processor, a communication interface, a computer-readable storage medium as described above, and a communication bus; wherein the processor, the communication interface, and the computer-readable storage medium communicate with each other via the communication bus; and the processor is used to execute a program stored in the computer-readable storage medium.

[0095] Parts not involved in the above embodiments are the same as the prior art or can be implemented by using the prior art, and will not be further described here.

[0096] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for judging the slow-blow of a PT fuse based on phase comparison, characterized in that: The method uses PT fuse slow-blow detection for judgment, and the PT fuse slow-blow detection includes: Compare the three-phase voltage amplitude of the PT signal connected to the online operation control channel with the three-phase voltage amplitude of the PT signal connected to the standby control channel phase by phase; If any phase voltage deviation reaches the phase voltage deviation threshold and lasts for more than a preset time, it is determined that the PT with a lower phase voltage amplitude in that phase has a slow-blow fuse fault, and the PT slow-blow fuse alarm is triggered.

2. A PT fuse slow-blow judgment method based on phase comparison according to claim 1, characterized in that: The PT insurance slow-fuse detection sets the start conditions, and the start conditions include: Determine whether the average value of the three-phase voltage amplitude output by the PT is greater than the PT insurance slow-fuse detection start threshold; If the average value of the three-phase voltage amplitude output by the PT is greater than the PT insurance slow-blow detection start threshold, the PT insurance slow-blow detection is started.

3. A method for judging the slow-blow of a PT fuse based on phase comparison according to claim 2, characterized in that: The PT insurance slow-blow detection start threshold is set to 0.5Un, where Un is the stator voltage rated value.

4. A method for judging the slow-blow of a PT fuse based on phase comparison according to claim 1, characterized in that: The PT insurance slow-blow detection also includes: The online operation control channel obtains the three-phase voltage amplitude of the PT signal connected to the standby control channel through communication.

5. A PT fuse slow-blow judgment method based on phase comparison according to any one of claims 1 to 4, characterized in that: The phase voltage deviation threshold is set to 0.05Un, the preset time length is set to 5 seconds, and Un is the stator voltage rated value.

6. A method for judging the slow-blow of a PT fuse based on phase comparison according to claim 5, characterized in that: The PT insurance slow-blow detection also includes: The three-phase voltage amplitude of the PT signal connected to the online operation control channel is compared phase by phase with the three-phase voltage amplitude of the PT signal connected to the standby control channel in a query cycle of 4 milliseconds.

7. A method for judging the slow-blow of a PT fuse based on phase comparison according to claim 6, characterized in that: When comparing the three-phase voltage amplitude of the PT signal connected to the online operation control channel with the three-phase voltage amplitude of the PT signal connected to the standby control channel phase by phase, if the voltage deviation of any phase reaches 0.05Un, the PT insurance slow-blow fault counter of the phase is incremented, and it is determined whether the PT insurance slow-blow fault counter of the phase reaches 1250; If the phase PT fuse slow-blow fault counter reaches 1250, the phase PT fuse slow-blow flag is set; If the PT fuse slow-blow mark appears in any phase, the PT fuse slow-blow total mark is set and the PT fuse slow-blow alarm is triggered.

8. A method for judging the slow-blow of a PT fuse based on phase comparison according to claim 7, characterized in that: When comparing the three-phase voltage amplitude of the PT signal connected to the online operation control channel with the three-phase voltage amplitude of the PT signal connected to the standby control channel phase by phase, if the voltage deviation of any phase does not reach 0.05Un, the slow-blow fault counter of the PT fuse of that phase is set to 0 and the slow-blow flag of the PT fuse of that phase is cleared.

9. A computer-readable storage medium storing one or more programs, characterized in that: When the one or more programs are executed, the PT fuse slow-blow judgment method based on phase comparison as described in any one of claims 1 to 8 can be implemented.

10. An electronic device comprising a processor, a communication interface, the computer-readable storage medium of claim 9, and a communication bus; wherein: The processor, the communication interface, and the computer-readable storage medium communicate with each other via a communication bus; It is characterized in that The processor is configured to execute a program stored in a computer-readable storage medium.

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