Excitation system fault recognition method based on phase voltage and phase current and device thereof

Abstract

The application provides a fault identification method and device of an excitation system based on phase voltage and phase current, and relates to the field of power systems. According to a cycle integral algorithm, three-phase phase current instantaneous values of a three-phase alternating current side current transformer of a small current test platform of a generator excitation system, three-phase phase voltage instantaneous values of a low voltage side of a synchronous transformer and rectifier output voltage instantaneous values are calculated to obtain three-phase phase current effective values, three-phase phase voltage effective values and rectifier output voltage effective values. An average value of the three-phase phase voltage effective values and the rectifier output voltage effective values are used to obtain a measured thyristor trigger angle during an open-loop load test. If a difference between the measured thyristor trigger angle and a given thyristor trigger angle is greater than a first preset threshold value, a fault phase is determined according to a first constraint relationship corresponding to the three-phase phase current effective values and a second constraint relationship corresponding to the three-phase phase voltage effective values after the thyristor is closed. The application has stronger anti-interference capability and strong engineering applicability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power systems and excitation systems, and particularly relates to an excitation system fault identification method based on phase voltage and phase current and a device thereof. BACKGROUND

[0002] The excitation system of a power plant plays a crucial role in the stability and safety of a unit, and the reliability of the core thyristor elements (or IGBTs), fast fuses, pulse triggers and other devices of the rectifier cabinet of the excitation system is of great importance to the stable operation of the unit. The small current test of the excitation system is the most effective and direct method to judge the performance of the three-phase fully controlled bridge thyristors of the excitation system power rectifier, and is an important content of the “DL / T 1166-2012 Field Test Guide for Large Generator Excitation System”. In the traditional way, on the one hand, the excitation small current test needs to draw three-phase alternating current power from outside and a test platform needs to be built on site, which is relatively inconvenient for on-site coordination and implementation, and on the other hand, it cannot intelligently judge whether the thyristors, fast fuses and other devices of the three-phase fully controlled bridge of the excitation system rectification power cabinet are faulty. SUMMARY

[0003] The present application aims to at least partially solve one of the technical problems in the related art.

[0004] To this end, one purpose of the present application is to provide an excitation system fault identification method based on phase voltage and phase current. The A-phase phase current instantaneous value, B-phase phase current instantaneous value and C-phase phase current instantaneous value corresponding to the three-phase alternating current side current transformer of the small current test platform of the generator excitation system are obtained, and the synchronous A-phase phase voltage instantaneous value, B-phase phase voltage instantaneous value and C-phase phase voltage instantaneous value monitored by the low-voltage side of the synchronous transformer are obtained, and the rectification output voltage instantaneous value is obtained. According to the cycle integration algorithm, the effective value of the A-phase phase current instantaneous value, B-phase phase current instantaneous value, C-phase phase current instantaneous value, A-phase phase voltage instantaneous value, B-phase phase voltage instantaneous value, C-phase phase voltage instantaneous value and rectification output voltage instantaneous value is calculated, respectively, to obtain the A-phase phase current effective value, B-phase phase current effective value, C-phase phase current effective value, A-phase phase voltage effective value, B-phase phase voltage effective value, C-phase phase voltage effective value and rectification output voltage effective value. The average value of the A-phase phase voltage effective value, B-phase phase voltage effective value and C-phase phase voltage effective value is obtained, and the average value and the rectification output voltage effective value are used to obtain the measured thyristor trigger angle during the small current open-loop load test of the generator excitation system. In response to the difference between the measured thyristor trigger angle and the given thyristor trigger angle being greater than a first preset threshold value, the fault phase is determined according to the first constraint relationship corresponding to the A-phase phase current effective value, B-phase phase current effective value and C-phase phase current effective value and the second constraint relationship corresponding to the A-phase phase voltage effective value, B-phase phase voltage effective value and C-phase phase voltage effective value after the thyristor is closed.

[0005] A second object of the present application is to provide a fault identification device for an excitation system based on phase voltage and phase current.

[0006] A third object of the present application is to provide an electronic device.

[0007] A fourth object of the present application is to provide a non-transitory computer-readable storage medium.

[0008] A fifth object of the present application is to provide a computer program product.

[0009] To achieve the above objects, the first aspect of the present application provides a fault identification method for an excitation system based on phase voltage and phase current, comprising: obtaining an instantaneous value of a phase current of phase A, an instantaneous value of a phase current of phase B and an instantaneous value of a phase current of phase C corresponding to a three-phase alternating current side current transformer of a small current test platform of a generator excitation system, and obtaining an instantaneous value of a synchronous phase voltage of phase A, an instantaneous value of a synchronous phase voltage of phase B and an instantaneous value of a synchronous phase voltage of phase C monitored at a low voltage side of a synchronous transformer, and obtaining an instantaneous value of a rectifier output voltage; calculating the effective values of the instantaneous value of the phase current of phase A, the instantaneous value of the phase current of phase B, the instantaneous value of the phase current of phase C, the instantaneous value of the phase voltage of phase A, the instantaneous value of the phase voltage of phase B, the instantaneous value of the phase voltage of phase C and the instantaneous value of the rectifier output voltage according to the cycle integration algorithm, respectively, to obtain the effective value of the phase current of phase A, the effective value of the phase current of phase B, the effective value of the phase current of phase C, the effective value of the phase voltage of phase A, the effective value of the phase voltage of phase B, the effective value of the phase voltage of phase C and the effective value of the rectifier output voltage; obtaining the average value of the effective value of the phase voltage of phase A, the effective value of the phase voltage of phase B and the effective value of the phase voltage of phase C, and obtaining the measured thyristor trigger angle during the small current open-loop load test of the generator excitation system according to the average value and the effective value of the rectifier output voltage; in response to the difference between the measured thyristor trigger angle and a given thyristor trigger angle being greater than a first preset threshold value, determining the fault phase according to a first constraint relationship corresponding to the effective value of the phase current of phase A, the effective value of the phase current of phase B and the effective value of the phase current of phase C and a second constraint relationship corresponding to the effective value of the phase voltage of phase A, the effective value of the phase voltage of phase B and the effective value of the phase voltage of phase C after the thyristor is closed.

[0010] According to one embodiment of the present application, the effective values of the instantaneous value of the phase current of phase A, the instantaneous value of the phase current of phase B and the instantaneous value of the phase current of phase C are calculated according to the cycle integration algorithm, and the calculation formula of the effective value of the phase current of phase A, the effective value of the phase current of phase B and the effective value of the phase current of phase C is:

[0011]

[0012] In the above formula, m is any one of the phases A, B and C, I pm is the effective value of the phase current of the phase corresponding to m, i pmis the phase voltage effective value of the m corresponding phase, u

[0013] According to one embodiment of the application, the effective value of the A-phase voltage instantaneous value, the B-phase voltage instantaneous value and the C-phase voltage instantaneous value are calculated according to the cycle integration algorithm, and the calculation formula of the A-phase voltage effective value, the B-phase voltage effective value and the C-phase voltage effective value is:

[0014]

[0015] In the above formula, m is any one of the A, B and C phases, U pm is the phase voltage effective value of the m corresponding phase, u pm is the phase voltage instantaneous value of the m corresponding phase.

[0016] According to one embodiment of the application, the effective value of the rectifier output voltage instantaneous value is calculated according to the cycle integration algorithm, and the calculation formula of the rectifier output voltage effective value is:

[0017]

[0018] In the above formula, U d is the rectifier output voltage effective value, u d is the rectifier output voltage instantaneous value.

[0019] According to one embodiment of the application, after the thyristor is closed, the fault phase is determined according to the first constraint relationship corresponding to the A-phase current effective value, the B-phase current effective value and the C-phase current effective value, and the second constraint relationship corresponding to the A-phase voltage effective value, the B-phase voltage effective value and the C-phase voltage effective value, including: after the thyristor is closed, the A-phase minimum phase current effective value, the B-phase minimum phase current effective value and the C-phase minimum phase current effective value are obtained; the phase in the A-phase, the B-phase and the C-phase that satisfies the first constraint relationship and satisfies the second constraint relationship is taken as the fault phase, wherein the first constraint relationship is that the minimum phase current effective value is less than or equal to a second preset threshold, and the second constraint relationship is that the phase voltage effective value is greater than or equal to a third preset threshold, and the second constraint relationship is used to limit the generator excitation system to be in a working state and the fault to occur in a region after the synchronous transformer.

[0020] According to one embodiment of the application, the first constraint relationship is represented as:

[0021] min(i m )≤i set m=A, B, C.

[0022] In the above formula, min(i m ) represents the minimum phase current effective value corresponding to each phase among the A, B and C phases, i set represents the second preset threshold;

[0023] wherein the second constraint relationship is expressed as:

[0024] u pm ≥u set m=A, B, C.

[0025] In the above formula, m is any one of A, B, C, U pm represents the effective value of the phase voltage of the phase corresponding to m, u set represents a third preset threshold.

[0026] According to an embodiment of the present application, the measured thyristor trigger angle during the small current open-loop load test of the generator excitation system is obtained according to the average value and the effective value of the rectified output voltage, comprising:

[0027] Based on the principle of three-phase full-bridge rectification, the trigger angle of 60 degrees is taken as a dividing line, and the formula for calculating the measured thyristor trigger angle a is as follows:

[0028]

[0029]

[0030] In the above formula, a represents the measured thyristor trigger angle, U p represents the average value of the effective value of the phase voltage of phase A, the effective value of the phase voltage of phase B and the effective value of the phase voltage of phase C, U d represents the effective value of the rectified output voltage.

[0031] According to an embodiment of the present application, the excitation system fault recognition method based on phase voltage and phase current further comprises: in response to the difference between the measured thyristor trigger angle and the given thyristor trigger angle being less than or equal to a first preset threshold, determining that the generator excitation system is fault-free.

[0032] To achieve the above object, the second aspect of the present application proposes a kind of excitation system fault identification device based on phase voltage, phase current, comprising: acquisition module, for obtaining the instantaneous value of A-phase phase current, B-phase phase current and C-phase phase current corresponding to the three-phase alternating current side current transformer of generator excitation system small current test platform, and obtaining the instantaneous value of synchronous A-phase phase voltage, B-phase phase voltage and C-phase phase voltage monitored by synchronous transformer low voltage side, and the instantaneous value of rectifier output voltage;Integral module, for calculating the effective value of A-phase phase current, B-phase phase current, C-phase phase current, A-phase phase voltage, B-phase phase voltage, C-phase phase voltage and rectifier output voltage according to the cycle integral algorithm respectively, and A-phase phase current effective value, B-phase phase current effective value, C-phase phase current effective value, A-phase phase voltage effective value, B-phase phase voltage effective value, C-phase phase voltage effective value and rectifier output voltage effective value are obtained;Calculation module, for obtaining the average of A-phase phase voltage effective value, B-phase phase voltage effective value and C-phase phase voltage effective value, and according to the average and rectifier output voltage effective value, the measured thyristor trigger angle when the small current open-loop load test of generator excitation system is obtained;Judgment module, for responding to the difference between measured thyristor trigger angle and given thyristor trigger angle greater than first preset threshold, after thyristor is closed, according to the first constraint relationship corresponding to A-phase phase current effective value, B-phase phase current effective value and C-phase phase current effective value and the second constraint relationship corresponding to A-phase phase voltage effective value, B-phase phase voltage effective value and C-phase phase voltage effective value, determine fault phase.

[0033] According to one embodiment of the present application, in integral module, the effective value of A-phase phase current, B-phase phase current and C-phase phase current is calculated according to the cycle integral algorithm, and the calculation formula of A-phase phase current effective value, B-phase phase current effective value and C-phase phase current effective value is as follows:

[0034]

[0035] In the above formula, m is any one of A, B and C, I pm is the effective value of phase current corresponding to m, i pm is the instantaneous value of phase current corresponding to m.

[0036] According to one embodiment of the present application, in integral module, the effective value of A-phase phase voltage, B-phase phase voltage and C-phase phase voltage is calculated according to the cycle integral algorithm, and the calculation formula of A-phase phase voltage effective value, B-phase phase voltage effective value and C-phase phase voltage effective value is as follows:

[0037]

[0038] In the formula, m is any one of the three phases A, B, and C, U pm is the effective value of the phase voltage corresponding to m, u pm is the instantaneous value of the phase voltage corresponding to m.

[0039] According to one embodiment of the present application, in the integration module, the instantaneous value of the rectified output voltage is calculated according to the cycle integration algorithm to obtain the calculation formula of the effective value of the rectified output voltage:

[0040]

[0041] In the formula, U d is the effective value of the rectified output voltage, u d is the instantaneous value of the rectified output voltage.

[0042] According to one embodiment of the present application, the judgment module is further configured to: after the thyristor is closed, obtain the minimum phase current effective value of the A phase, the minimum phase current effective value of the B phase, and the minimum phase current effective value of the C phase; and take the phase that meets the first constraint relationship and the second constraint relationship among the A phase, the B phase, and the C phase as the fault phase, wherein the first constraint relationship is that the minimum phase current effective value is less than or equal to a second preset threshold, and the second constraint relationship is that the effective value of the phase voltage is greater than or equal to a third preset threshold, and the second constraint relationship is used to limit the generator excitation system to be in a working state and the fault to occur in a region after the synchronous transformer.

[0043] According to one embodiment of the present application, in the judgment module, the first constraint relationship is represented as:

[0044] min(i m )≤i set m=A, B, C.

[0045] In the formula, min(i m ) represents the minimum phase current effective value corresponding to each phase among the three phases A, B, and C, i set represents the second preset threshold;

[0046] The second constraint relationship is represented as:

[0047] u pm ≥u set m=A, B, C.

[0048] In the formula, m is any one of the three phases A, B, and C, U pm represents the effective value of the phase voltage corresponding to m, u set represents the third preset threshold.

[0049] According to one embodiment of the present application, the calculation module is further configured to: based on a three-phase full-bridge rectification principle, taking 60 degrees as a demarcation line for a trigger angle, and calculating the measured thyristor trigger angle a according to the following formula:

[0050]

[0051]

[0052] In the above formula, a represents the measured thyristor trigger angle, U p represents the average of the A-phase phase voltage effective value, the B-phase phase voltage effective value, and the C-phase phase voltage effective value, U d represents the rectified output voltage effective value.

[0053] According to one embodiment of the present application, the judgment module is further configured to: in response to the difference between the measured thyristor trigger angle and the given thyristor trigger angle being less than or equal to a first preset threshold, determining that the generator excitation system is fault-free.

[0054] To achieve the above object, a third aspect of the present application provides an electronic device, comprising: at least one processor; and a memory in communication connection with the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to implement the excitation system fault identification method based on phase voltage and phase current as described in the first aspect of the present application.

[0055] To achieve the above object, a fourth aspect of the present application provides a non-transitory computer readable storage medium storing computer instructions, wherein the computer instructions are used to implement the excitation system fault identification method based on phase voltage and phase current as described in the first aspect of the present application.

[0056] To achieve the above object, a fifth aspect of the present application provides a computer program product comprising a computer program, wherein the computer program, when executed by a processor, implements the excitation system fault identification method based on phase voltage and phase current as described in the first aspect of the present application.

[0057] The present application at least achieves the following beneficial effects: the embodiments of the present application perform the excitation system fault identification of the generator based on phase voltage and phase current, are not affected by factors such as noise, abnormal data, and hardware conditions, have stronger anti-interference ability, have strong engineering applicability, implement a more robust excitation system fault identification method, and have important significance for the excitation system preventive test of the power plant with a regular detection and a device maintenance plan and the newly operated power plant unit. BRIEF DESCRIPTION OF DRAWINGS

[0058] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings of which:

[0059] Figure 1 is a schematic diagram of an exemplary embodiment of a method for identifying a fault of an excitation system based on phase voltage and phase current according to an embodiment of the present application.

[0060] Figure 2 is a schematic diagram of a small current load test of an open loop mode of a generator excitation system according to an embodiment of the present application.

[0061] Figure 3 is a flowchart of an exemplary embodiment of a method for identifying a fault of an excitation system based on phase voltage and phase current according to an embodiment of the present application.

[0062] FIG. 4(a) is a schematic diagram of a normal condition identification waveform at a 30° thyristor trigger angle identified by a method for identifying a fault of an excitation system based on phase voltage and phase current according to an embodiment of the present application.

[0063] FIG. 4(b) is a schematic diagram of a normal condition identification waveform at a 60° thyristor trigger angle identified by a method for identifying a fault of an excitation system based on phase voltage and phase current according to an embodiment of the present application.

[0064] FIG. 5(a) is a schematic diagram of an A-phase fault condition identification waveform at a 60° thyristor trigger angle identified by a method for identifying a fault of an excitation system based on phase voltage and phase current according to an embodiment of the present application.

[0065] FIG. 5(b) is a schematic diagram of a B-phase fault condition identification waveform at a 62° thyristor trigger angle identified by a method for identifying a fault of an excitation system based on phase voltage and phase current according to an embodiment of the present application.

[0066] FIG. 5(c) is a schematic diagram of a B-phase and C-phase fault condition identification waveform at a 120° thyristor trigger angle identified by a method for identifying a fault of an excitation system based on phase voltage and phase current according to an embodiment of the present application.

[0067] Figure 6 is a schematic diagram of a device for identifying a fault of an excitation system based on phase voltage and phase current according to an embodiment of the present application.

[0068] Figure 7 is a schematic diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0069] Embodiments of the present application are described below in detail, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.

[0070] Figure 1 is a schematic diagram of an exemplary embodiment of a method for identifying faults of an excitation system based on phase voltage and phase current shown in the present application, as shown in Figure 1 The method for identifying faults of an excitation system based on phase voltage and phase current includes the following steps:

[0071] S101, obtaining A-phase phase current instantaneous value, B-phase phase current instantaneous value and C-phase phase current instantaneous value corresponding to three-phase alternating current side current transformers of a generator excitation system small current test platform, and obtaining synchronous A-phase phase voltage instantaneous value, B-phase phase voltage instantaneous value and C-phase phase voltage instantaneous value monitored by a synchronous transformer low-voltage side, and obtaining rectifier output voltage instantaneous value.

[0072] Figure 2 is a schematic diagram of a small current load test of a generator excitation system open loop mode shown in the present application, as shown in Figure 2 When the small current load test of the generator excitation system open loop is carried out, the A-phase phase current instantaneous value i pA , B-phase phase current instantaneous value i pB and C-phase phase current instantaneous value i pC corresponding to three-phase alternating current side current transformers TA1, TA2 and TA3 of the generator excitation system small current test platform are obtained, and the synchronous A-phase phase voltage instantaneous value u pA , B-phase phase voltage instantaneous value u pB and C-phase phase voltage instantaneous value u pC monitored by the synchronous transformer low-voltage side are obtained, and the rectifier output voltage instantaneous value u d is obtained.

[0073] S102, according to the cycle integral algorithm, the effective value calculation is carried out on the A-phase phase current instantaneous value, B-phase phase current instantaneous value, C-phase phase current instantaneous value, A-phase phase voltage instantaneous value, B-phase phase voltage instantaneous value, C-phase phase voltage instantaneous value and rectifier output voltage instantaneous value, respectively, to obtain A-phase phase current effective value, B-phase phase current effective value, C-phase phase current effective value, A-phase phase voltage effective value, B-phase phase voltage effective value, C-phase phase voltage effective value and rectifier output voltage effective value.

[0074] According to the cycle integral algorithm, the effective value of the A-phase phase current, the B-phase phase current and the C-phase phase current are calculated respectively to obtain the A-phase phase current effective value, the B-phase phase current effective value and the C-phase phase current effective value, and the corresponding calculation formula is:

[0075]

[0076] In the above formula, m is any one of the A-phase, the B-phase and the C-phase, I pm is the effective value of the phase current of the m corresponding phase, i pm is the instantaneous value of the phase current of the m corresponding phase.

[0077] According to the cycle integral algorithm, the effective value of the A-phase phase voltage, the B-phase phase voltage and the C-phase phase voltage are calculated respectively to obtain the A-phase phase voltage effective value, the B-phase phase voltage effective value and the C-phase phase voltage effective value, and the corresponding calculation formula is:

[0078]

[0079] In the above formula, m is any one of the A-phase, the B-phase and the C-phase, U pm is the effective value of the phase voltage of the m corresponding phase, u pm is the instantaneous value of the phase voltage of the m corresponding phase.

[0080] According to the cycle integral algorithm, the effective value of the rectifier output voltage is calculated, and the calculation formula of the rectifier output voltage effective value is:

[0081]

[0082] In the above formula, U d is the effective value of the rectifier output voltage, u d is the instantaneous value of the rectifier output voltage.

[0083] Compared with the root mean square calculation method, the cycle integral algorithm is more accurate for calculating irregular waveforms (such as pulsating rectified waveforms) and is closer to the true situation.

[0084] In S103, the average value of the A-phase phase voltage effective value, the B-phase phase voltage effective value and the C-phase phase voltage effective value is obtained, and the measured thyristor trigger angle during the small current open-loop load test of the generator excitation system is obtained according to the average value and the rectifier output voltage effective value.

[0085] The average value of the A-phase phase voltage effective value, the B-phase phase voltage effective value and the C-phase phase voltage effective value is obtained, and the average value is denoted as U p , wherein

[0086] According to the average value U pand the rectified output voltage effective value U d , obtain the measured thyristor trigger angle a of the generator excitation system small current open loop load test.

[0087] From the principle of three-phase full-bridge rectification, the trigger angle of 60 degrees is a dividing line, and the waveform is discontinuous. The application adopts the waveform reverse thinking to separately calculate the measured thyristor trigger angle a. The formula for calculating the measured thyristor trigger angle a is as follows:

[0088]

[0089]

[0090] S104, in response to the difference between the measured thyristor trigger angle and the given thyristor trigger angle being greater than a first preset threshold, after the thyristor is closed, the fault phase is determined according to the first constraint relationship corresponding to the A-phase current effective value, the B-phase current effective value and the C-phase current effective value, and the second constraint relationship corresponding to the A-phase voltage effective value, the B-phase voltage effective value and the C-phase voltage effective value.

[0091] Under normal circumstances, the measured and calculated trigger angle a and the given trigger angle a of the excitation regulating device 给定 tend to be consistent; under fault conditions, the measured and calculated trigger angle a and the given trigger angle a of the excitation regulating device 给定 have a large difference, and the difference between the measured and calculated trigger angle a and the given trigger angle a of the excitation regulating device 给定 is calculated. A first preset threshold is preset, and the first preset threshold is denoted as a set , if the difference between the measured and calculated trigger angle a and the given trigger angle a of the excitation regulating device 给定 is greater than the first preset threshold, it indicates that there is a fault phase, that is, if |a-a 给定 |>a set , it indicates that there is a fault phase.

[0092] Further, if the difference between the measured thyristor trigger angle and the given thyristor trigger angle is less than or equal to the first preset threshold, it is determined that the generator excitation system has no fault, that is, if |a-a 给定 |≤a set , it is determined that the generator excitation system has no fault.

[0093] Wherein, the setting of a set is based on the hardware collection accuracy error and the maximum error under the maximum load condition, and a given value considering the reliability margin.

[0094] If it is judged that there is a fault phase, after the thyristor is closed, the fault phase is determined according to a first constraint relationship corresponding to the A-phase phase current effective value, the B-phase phase current effective value and the C-phase phase current effective value, and a second constraint relationship corresponding to the A-phase phase voltage effective value, the B-phase phase voltage effective value and the C-phase phase voltage effective value. Specifically, after the thyristor is closed, the A-phase minimum phase current effective value, the B-phase minimum phase current effective value and the C-phase minimum phase current effective value are obtained, and the phase that satisfies the first constraint relationship and the second constraint relationship among the A-phase, the B-phase and the C-phase is taken as the fault phase, wherein the first constraint relationship is that the minimum phase current effective value is less than or equal to a second preset threshold value, and the second constraint relationship is that the phase voltage effective value is greater than or equal to a third preset threshold value, and the second constraint relationship is used to limit the generator excitation system to be in a working state and the fault to occur in a region after the synchronous transformer.

[0095] wherein the first constraint relationship is represented as:

[0096] min(i m )≤i set m=A, B, C.

[0097] In the above formula, min(i m ) represents the minimum phase current effective value corresponding to each phase among the A-phase, the B-phase and the C-phase, and i set represents the second preset threshold value.

[0098] wherein the second constraint relationship is represented as: u pm ≥u set m=A, B, C.

[0099] In the above formula, m is any one of the A-phase, the B-phase and the C-phase, U pm represents the phase voltage effective value of the phase corresponding to m, and u set represents the third preset threshold value.

[0100] That is, the phase that simultaneously satisfies min(i m )≤i set && pm ≥u set (m=A, B, C) among the A-phase, the B-phase and the C-phase is determined as the fault phase.

[0101] wherein the second preset threshold value i set is set according to the minimum conduction freewheeling capability of the thyristor, the hardware collection accuracy error and the maximum error under the maximum load condition, and a given value considering the reliability margin. The third preset threshold value u set may generally be set as 90% of the rated phase voltage.

[0102] The embodiment of the application is based on phase voltage and phase current to identify the fault of the generator excitation system, is not affected by factors such as noise, abnormal data, hardware condition limitation, has stronger anti-interference ability, strong engineering applicability, realizes a more robust excitation system fault phase identification method, and has important significance for the excitation system preventive test of the power plant with regular detection and equipment maintenance plan and the newly operated power plant unit.

[0103] Figure 3 is a flowchart of an exemplary embodiment of the excitation system fault identification method based on phase voltage and phase current shown in the application, as shown in Figure 3 the excitation system fault identification method based on phase voltage and phase current, comprising the following steps: when the open-loop small current load test of the generator excitation system is performed, the A-phase phase current instantaneous value i pA , the B-phase phase current instantaneous value i pB and the C-phase phase current instantaneous value i pC corresponding to the three-phase alternating current side current transformers TA1, TA2 and TA3 of the generator excitation system small current test platform are obtained, and the synchronous A-phase phase voltage instantaneous value u pA , the synchronous B-phase phase voltage instantaneous value u pB and the synchronous C-phase phase voltage instantaneous value u pC monitored by the low-voltage side of the synchronous transformer are obtained, and the rectifier output voltage instantaneous value u d is obtained.

[0104] The A-phase phase current instantaneous value, the B-phase phase current instantaneous value and the C-phase phase current instantaneous value are calculated according to the cycle integration algorithm to obtain the A-phase phase current effective value, the B-phase phase current effective value and the C-phase phase current effective value, and the corresponding calculation formula is:

[0105]

[0106] In the above formula, m is any one of A, B and C, I pm is the effective value of the phase current of the corresponding phase of m, and i pm is the phase current instantaneous value of the corresponding phase of m.

[0107] The A-phase phase voltage instantaneous value, the B-phase phase voltage instantaneous value and the C-phase phase voltage instantaneous value are calculated according to the cycle integration algorithm to obtain the A-phase phase voltage effective value, the B-phase phase voltage effective value and the C-phase phase voltage effective value, and the corresponding calculation formula is:

[0108]

[0109] In the above formula, m is any one of A, B and C, U pm is the effective value of the phase voltage of the corresponding phase of m, and u pmis the instantaneous value of the phase voltage of the m corresponding phase.

[0110] According to the cycle integral algorithm, the effective value of the rectified output voltage is calculated, and the calculation formula of the effective value of the rectified output voltage is:

[0111]

[0112] In the above formula, U d is the effective value of the rectified output voltage, and u d is the instantaneous value of the rectified output voltage.

[0113] Compared with the root mean square calculation method, the cycle integral algorithm is more accurate for calculating irregular waveforms (such as pulsating rectified waveforms) and is closer to the real situation.

[0114] The average value of the effective value of the A-phase phase voltage, the effective value of the B-phase phase voltage, and the effective value of the C-phase phase voltage is obtained, and the average value is denoted as U p , wherein

[0115] According to the average value U p and the effective value of the rectified output voltage U d , the measured thyristor trigger angle a of the small current open loop load test of the generator excitation system is obtained.

[0116] According to the principle of three-phase full-bridge rectification, the trigger angle of 60 degrees is a dividing line, and the waveform is discontinuous. The application adopts the waveform reverse thinking to separately calculate the measured thyristor trigger angle a. The formula for calculating the measured thyristor trigger angle a is as follows:

[0117]

[0118]

[0119] A first preset threshold is preset, and the first preset threshold is denoted as a set . If the difference between the measured and calculated trigger angle a and the given trigger angle a 给定 of the excitation regulating device is greater than the first preset threshold, it indicates that there is a fault phase, that is, if |a-a 给定 |>a set , it indicates that there is a fault phase.

[0120] Further, if the difference between the measured thyristor trigger angle and the given thyristor trigger angle is less than or equal to the first preset threshold, it is determined that the generator excitation system is fault-free, that is, if |a-a 给定 |≤a set , it is determined that the generator excitation system is fault-free.

[0121] If it is judged that there is a fault phase, after the thyristor is closed, the fault phase is determined according to the first constraint relationship corresponding to the A-phase current effective value, the B-phase current effective value and the C-phase current effective value and the second constraint relationship corresponding to the A-phase voltage effective value, the B-phase voltage effective value and the C-phase voltage effective value. That is, the phase that simultaneously satisfies min(i m )≤i set &&u pm ≥u set (m=A, B, C) in the A-phase, the B-phase and the C-phase is determined as the fault phase.

[0122] The following shows the waveform diagram obtained when the simulation experiment of the excitation system fault recognition method based on the phase voltage and the phase current is performed, Fig. 4(a) is a normal working condition recognition waveform schematic diagram under the 30° thyristor trigger angle recognized by the excitation system fault recognition method based on the phase voltage and the phase current shown in the application; Fig. 4(b) is a normal working condition recognition waveform schematic diagram under the 60° thyristor trigger angle recognized by the excitation system fault recognition method based on the phase voltage and the phase current shown in the application; Fig. 5(a) is an A-phase fault working condition recognition waveform schematic diagram under the 60° thyristor trigger angle recognized by the excitation system fault recognition method based on the phase voltage and the phase current shown in the application; Fig. 5(b) is a B-phase fault working condition recognition waveform schematic diagram under the 62° thyristor trigger angle recognized by the excitation system fault recognition method based on the phase voltage and the phase current shown in the application; Fig. 5(c) is a B-phase and C-phase fault working condition recognition waveform schematic diagram under the 120° thyristor trigger angle recognized by the excitation system fault recognition method based on the phase voltage and the phase current shown in the application.

[0123] It is verified that the excitation system fault recognition method based on the phase voltage and the phase current proposed in the application has stronger anti-interference ability, strong engineering applicability and realizes more robust excitation system fault phase recognition method, which is not affected by factors such as noise, abnormal data and hardware conditions, and has important significance for the periodic detection, power plant with equipment maintenance plan and new power plant unit to perform excitation system preventive test.

[0124] Figure 6 is a schematic diagram of an excitation system fault recognition device based on the phase voltage and the phase current shown in the application, as shown in Figure 6 the excitation system fault recognition device 600 based on the phase voltage and the phase current includes an acquisition module 601, an integration module 602, a calculation module 603 and a judgment module 604, wherein:

[0125] The acquisition module 601 is used to acquire the instantaneous values ​​of the A-phase current, B-phase current, and C-phase current corresponding to the current transformers on the three-phase AC side of the generator excitation system small current test platform, as well as the instantaneous values ​​of the A-phase voltage, B-phase voltage, and C-phase voltage monitored on the low-voltage side of the synchronous transformer, and the instantaneous value of the rectified output voltage.

[0126] The integration module 602 is used to calculate the effective values ​​of the instantaneous values ​​of the phase currents of phases A, B, and C, the phase voltages of phases A, B, and C, and the rectified output voltage according to the cycle integration algorithm, and obtain the effective values ​​of the phase currents of phases A, B, and C, the phase voltages of phases A, B, and C, and the rectified output voltage, respectively.

[0127] The calculation module 603 is used to obtain the average value of the effective value of phase A voltage, effective value of phase B voltage and effective value of phase C voltage, and to obtain the measured thyristor firing angle during the small current open-loop load test of the generator excitation system based on the average value and the effective value of the rectified output voltage.

[0128] The judgment module 604 is used to determine the faulty phase in response to the difference between the measured thyristor firing angle and the given thyristor firing angle being greater than a first preset threshold after the thyristor is turned off, based on the first constraint relationship corresponding to the effective values ​​of the phase currents of phase A, phase currents of phase B and phase currents of phase C, and the second constraint relationship corresponding to the effective values ​​of the phase voltages of phase A, phase voltages of phase B and phase voltages of phase C.

[0129] This device identifies faults in the generator excitation system based on phase voltage and phase current. It is unaffected by factors such as noise, abnormal data, and hardware limitations, has stronger anti-interference capabilities, and is highly applicable to engineering projects. It achieves a more robust method for identifying excitation system faults and is of great significance for preventive testing of excitation systems in power plants with regular inspections and equipment maintenance plans, as well as for newly commissioned power plant units.

[0130] According to one embodiment of this application, in the integration module 602, the effective values ​​of the instantaneous values ​​of the phase currents A, B, and C are calculated respectively using the cycle integration algorithm. The calculation formulas for the effective values ​​of the phase currents A, B, and C are as follows:

[0131]

[0132] In the above formula, m is any one of the three phases A, B, and C, and I pm Let i be the effective value of the phase current corresponding to phase m. pmLet m be the instantaneous value of the phase current corresponding to phase m.

[0133] According to one embodiment of this application, in the integration module 602, the effective values ​​of the instantaneous values ​​of phase A voltage, phase B voltage, and phase C voltage are calculated respectively according to the cycle integration algorithm. The calculation formulas for the effective values ​​of phase A voltage, phase B voltage, and phase C voltage are as follows:

[0134]

[0135] In the above formula, m is any one of the three phases A, B, and C, and U pm Let u be the effective value of the phase voltage corresponding to phase m. pm Let m be the instantaneous value of the phase voltage corresponding to phase m.

[0136] According to one embodiment of this application, in the integration module 602, the effective value of the instantaneous value of the rectified output voltage is calculated based on the cycle integration algorithm, and the calculation formula for the effective value of the rectified output voltage is as follows:

[0137]

[0138] In the above formula, U d u is the effective value of the rectified output voltage. d This is the instantaneous value of the rectified output voltage.

[0139] According to one embodiment of this application, the judgment module 604 is further configured to: after the thyristor is turned off, obtain the effective value of the minimum phase current of phase A, the effective value of the minimum phase current of phase B, and the effective value of the minimum phase current of phase C; and designate the phase among phases A, B, and C that satisfies both the first constraint relationship and the second constraint relationship as the fault phase, wherein the first constraint relationship is that the effective value of the minimum phase current is less than or equal to a second preset threshold, and the second constraint relationship is that the effective values ​​of the phase voltages are all greater than or equal to a third preset threshold. The second constraint relationship is used to limit the area where the generator excitation system is in operation and the fault occurs after the synchronous transformer.

[0140] According to one embodiment of this application, in the determination module 604, the first constraint relationship is expressed as:

[0141] min(i m )≤i set m = A, B, C.

[0142] In the above formula, min(i m () represents the minimum effective value of the phase current in each of the three phases A, B, and C, i set This represents the second preset threshold.

[0143] The second constraint relationship is expressed as follows:

[0144] u pm ≥u set m = A, B, C.

[0145] In the above formula, m is any one of the three phases A, B, and C, U pm represents the effective value of the phase voltage of the phase corresponding to m, U set represents a third preset threshold.

[0146] According to an embodiment of the present application, the calculation module 603 is further configured to calculate the measured thyristor trigger angle a based on the three-phase full-bridge rectification principle, taking 60 degrees as a demarcation line, and the formula is as follows:

[0147]

[0148]

[0149] In the above formula, a represents the measured thyristor trigger angle, U p represents the average value of the effective value of the phase voltage of phase A, the effective value of the phase voltage of phase B, and the effective value of the phase voltage of phase C, U d represents the effective value of the rectified output voltage.

[0150] According to an embodiment of the present application, the judgment module 604 is further configured to determine that the generator excitation system is fault-free in response to the difference between the measured thyristor trigger angle and the given thyristor trigger angle being less than or equal to the first preset threshold.

[0151] To implement the above-mentioned embodiments, the embodiments of the present application further propose an electronic device 700, as shown in Figure 7 The electronic device 700 includes a processor 701 and a memory 702 in communication with the processor 701, and the memory 702 stores instructions executable by at least one processor 701, and the instructions are executed by at least one processor 701 to implement the excitation system fault identification method based on phase voltage and phase current as shown in the above-mentioned embodiments.

[0152] To implement the above-mentioned embodiments, the embodiments of the present application further propose a non-transitory computer readable storage medium storing computer instructions, wherein the computer instructions are used to cause a computer to implement the excitation system fault identification method based on phase voltage and phase current as shown in the above-mentioned embodiments.

[0153] To implement the above-mentioned embodiments, the embodiments of the present application further propose a computer program product including a computer program, and the computer program is executed by a processor to implement the excitation system fault identification method based on phase voltage and phase current as shown in the above-mentioned embodiments.

[0154] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0155] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0156] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0157] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A method for fault identification of an excitation system based on phase voltage and phase current, characterized in that, include: The instantaneous values ​​of phase A, phase B, and phase C currents corresponding to the current transformers on the three-phase AC side of the generator excitation system small current test platform are obtained, as well as the instantaneous values ​​of phase A, phase B, and phase C voltages monitored on the low-voltage side of the synchronous transformer, and the instantaneous value of the rectified output voltage are obtained. Based on the cycle integral algorithm, the effective values ​​of the instantaneous values ​​of the phase currents of phases A, B, and C, the phase voltages of phases A, B, and C, and the rectified output voltage are calculated respectively to obtain the effective values ​​of the phase currents of phases A, B, and C, the phase voltages of phases A, B, and C, and the rectified output voltage. The average value of the effective value of the phase voltage of phase A, the effective value of the phase voltage of phase B, and the effective value of the phase voltage of phase C are obtained, and the measured thyristor firing angle during the small current open-loop load test of the generator excitation system is obtained based on the average value and the effective value of the rectified output voltage. In response to the difference between the measured thyristor firing angle and the given thyristor firing angle being greater than a first preset threshold, after the thyristor is turned off, the faulty phase is determined according to the first constraint relationship corresponding to the effective values ​​of the phase currents of phase A, phase currents of phase B, and phase currents of phase C, and the second constraint relationship corresponding to the effective values ​​of the phase voltages of phase A, phase voltages of phase B, and phase voltages of phase C.

2. The method according to claim 1, characterized in that, The effective values ​​of the instantaneous values ​​of the phase currents A, B, and C are calculated using the cycle integral algorithm to obtain the corresponding effective values ​​of the phase currents A, B, and C. The calculation formulas are as follows: In the above formula, m is any one of the three phases A, B, and C, and I pm Let i be the effective value of the phase current corresponding to phase m. pm Let m be the instantaneous value of the phase current corresponding to phase m.

3. The method according to claim 1, characterized in that, The effective values ​​of the instantaneous voltages of phase A, phase B, and phase C are calculated using the cycle integral algorithm to obtain the corresponding effective values ​​of the phase A, phase B, and phase C voltages. The calculation formulas are as follows: In the above formula, m is any one of the three phases A, B, and C, and U pm Let u be the effective value of the phase voltage corresponding to phase m. pm Let m be the instantaneous value of the phase voltage corresponding to phase m.

4. The method according to claim 1, characterized in that, The formula for calculating the effective value of the rectified output voltage by performing an effective value calculation on the instantaneous value of the rectified output voltage using the cycle integral algorithm is as follows: In the above formula, U d u is the effective value of the rectified output voltage. d This is the instantaneous value of the rectified output voltage.

5. The method according to any one of claims 1-4, characterized in that, After the thyristor is turned off, the faulty phase is determined according to the first constraint relationship corresponding to the effective values ​​of the phase currents of phase A, phase currents of phase B, and phase currents of phase C, and the second constraint relationship corresponding to the effective values ​​of the phase voltages of phase A, phase voltages of phase B, and phase voltages of phase C, including: After the thyristor is turned off, the effective value of the minimum phase current of phase A, the effective value of the minimum phase current of phase B, and the effective value of the minimum phase current of phase C are obtained. The phases among phases A, B, and C that satisfy both the first and second constraints are designated as faulty phases. The first constraint is that the minimum effective value of the phase current is less than or equal to a second preset threshold, and the second constraint is that the effective values ​​of the phase voltages are all greater than or equal to a third preset threshold. The second constraint is used to limit the region where the generator excitation system is in operation and the fault occurs after the synchronous transformer.

6. The method according to claim 5, characterized in that, In the method: The first constraint relationship is expressed as: min(i m )≤i set m=A,B,C; In the above formula, min(i m () represents the minimum effective value of the phase current in each of the three phases A, B, and C, i set This represents the second preset threshold. The second constraint relationship is expressed as follows: u pm ≥u set m=A,B,C; In the above formula, m is any one of the three phases A, B, and C, and U pm u represents the effective value of the phase voltage corresponding to phase m. set This indicates the third preset threshold.

7. The method according to any one of claims 1-4, characterized in that, The step of obtaining the measured thyristor firing angle during the small-current open-loop load test of the generator excitation system based on the average value and the effective value of the rectified output voltage includes: Based on the principle of three-phase fully controlled bridge rectification, and taking the firing angle of 60 degrees as a dividing line, the formula for calculating the measured firing angle α of the thyristor is as follows: In the above formula, α represents the measured thyristor firing angle, U p U represents the average of the effective values ​​of phase A voltage, phase B voltage, and phase C voltage. d This indicates the effective value of the rectified output voltage.

8. The method according to claim 5, characterized in that, The method further includes: If the difference between the measured thyristor firing angle and the given thyristor firing angle is less than or equal to the first preset threshold, it is determined that the generator excitation system is fault-free.

9. A fault identification device for an excitation system based on phase voltage and phase current, characterized in that, include: The acquisition module is used to acquire the instantaneous values ​​of the A-phase current, B-phase current, and C-phase current corresponding to the current transformers on the three-phase AC side of the generator excitation system small current test platform, as well as the instantaneous values ​​of the A-phase voltage, B-phase voltage, and C-phase voltage monitored on the low-voltage side of the synchronous transformer, and the instantaneous value of the rectified output voltage. The integration module is used to calculate the effective values ​​of the instantaneous values ​​of the phase currents of phases A, B, and C, the phase voltages of phases A, B, and C, and the rectified output voltage according to the cycle integration algorithm, respectively, to obtain the effective values ​​of the phase currents of phases A, B, and C, the phase voltages of phases A, B, and C, and the rectified output voltage. The calculation module is used to obtain the average value of the effective value of the phase voltage of phase A, the effective value of the phase voltage of phase B, and the effective value of the phase voltage of phase C, and to obtain the measured thyristor firing angle during the small current open-loop load test of the generator excitation system based on the average value and the effective value of the rectified output voltage. The judgment module is used to determine the faulty phase after the thyristor is turned off, in response to the difference between the measured thyristor firing angle and the given thyristor firing angle being greater than a first preset threshold. This is based on a first constraint relationship corresponding to the effective values ​​of the phase currents of phase A, phase currents of phase B, and phase currents of phase C, and a second constraint relationship corresponding to the effective values ​​of the phase voltages of phase A, phase voltages of phase B, and phase voltages of phase C.

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