Generator plant short circuit test method, system, and storage medium

Abstract

This invention discloses a method, system, and storage medium for short-circuit testing of a generator plant. Utilizing the generator's output circuit breaker, the generator can be actively disconnected. Ultimately, under reverse power supply conditions, the polarity of the CTs on both sides of the main transformer and the auxiliary transformer can be tested. Furthermore, with the generator output circuit breaker closed, a short-circuit test on the first branch of the low-voltage side of the auxiliary transformer energizes the generator side, thus enabling the testing of the polarity of the CTs on the high-voltage side of the auxiliary transformer and the generator output side. Finally, the test results can be used to determine the results of all short-circuit test requirements in the generator system. This invention completes the short-circuit test requirements with fewer steps and eliminates the need for a grounding switch at the short-circuit point on the high-voltage side of the main transformer, significantly reducing test time and increasing test safety.

Description

Technical Field

[0001] This invention relates to the field of power supply, and in particular to a method, system and storage medium for short-circuit testing of generators. Background Technology

[0002] Generator plant system such as Figure 1 As shown, Figure 1 In this system, the generator output side is connected to the high-voltage plant service transformer and the main transformer, thereby supplying the generated electricity to the plant service load and the power grid. Figure 1 K1 to K5 are five short-circuit points that require short-circuit testing (generator output side short-circuit point, main transformer high-voltage side short-circuit point, and K4 and K5 branch short-circuit points on the low-voltage side of the plant service transformer). In traditional short-circuit testing, after the generator is started, each short-circuit point must be tested sequentially to verify the correctness of the CT polarity in the system. However, traditional short-circuit testing methods require testing too many short-circuit points, resulting in long testing times, personnel fatigue, and high coal consumption. In particular, the use of a grounding switch as the short-circuit point on the high-voltage side of the main transformer is not good for the grounding switch. Furthermore, because there are many switching operations required, the five-proof interlocking needs to be disengaged, which further increases the test length and the risks during operation, and in severe cases, may even lead to personnel injury or death. Summary of the Invention

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a short-circuit test method for generator plants, which can solve the problems of long test times and complex operations in existing short-circuit tests.

[0004] The present invention also proposes a generator plant short-circuit test system and a computer-readable storage medium for performing the above-described generator plant short-circuit test method.

[0005] According to a first aspect of the present invention, a generator plant short-circuit test method is provided, wherein the generator in the generator plant has an output circuit breaker on the output side of the generator, and the generator is connected to the main transformer and the plant service transformer through the output circuit breaker; The generator plant short-circuit test method includes: The system controls the outlet circuit breaker to open; controls the main transformer to transmit power from the grid to the high-voltage side of the plant transformer, and starts the auxiliary load so that the plant transformer and the main transformer can operate under load; and collects the first detection data of the CT detection point on the high-voltage side of the main transformer, the second detection data of the CT detection point on the high-voltage side of the plant transformer, and the third detection data of the CT detection point on the low-voltage side of the plant transformer. The main transformer is disconnected from the power grid and the outlet circuit breaker is closed; when the first branch of the low-voltage side of the plant transformer is short-circuited, the fourth detection data of the CT detection point on the output side of the generator and the fifth detection data of the CT detection point on the high-voltage side of the plant transformer are obtained. The short-circuit test results of the generator plant are determined based on the first test data, the second test data, the third test data, the fourth test data, and the fifth test data.

[0006] The generator short-circuit test method according to embodiments of the present invention has at least the following beneficial effects: The generator plant short-circuit test method of this invention utilizes the generator's output circuit breaker to actively disconnect the generator. This avoids damage to the generator when backfeeding power from the main transformer to the generator plant. Ultimately, it allows for the verification of CT polarity checks on both sides of the main transformer and the plant service transformer under the premise of backfeeding operation. Furthermore, with the generator output circuit breaker closed, a short-circuit test on the first branch of the low-voltage side of the plant service transformer energizes the generator side, thus verifying CT polarity checks on the high-voltage side of the plant service transformer and the generator output side. Finally, the test results can be used to determine the results of all short-circuit test requirements in the generator system. This generator plant short-circuit test method of this invention completes the short-circuit test requirements with fewer steps and eliminates the need for a grounding switch at the short-circuit point on the high-voltage side of the main transformer, significantly reducing test time and increasing test safety. This generator plant short-circuit test method of this invention can effectively reduce the time by more than half during actual short-circuit testing and has significant potential for widespread application.

[0007] According to some embodiments of the present invention, determining the short-circuit test results of the generator plant based on the first detection data, the second detection data, the third detection data, the fourth detection data, and the fifth detection data includes: The first experimental results of the high-voltage side of the main transformer, the low-voltage side of the main transformer, the high-voltage side of the plant service transformer, and the low-voltage side of the plant service transformer are determined based on the first detection data, the second detection data, and the third detection data. The second experimental results for the generator output side and the high-voltage side of the plant transformer are determined based on the fourth and fifth detection data. The short-circuit test results are determined based on the first and second experimental results.

[0008] According to some embodiments of the present invention, the first detection data includes the CT detection data of the first circuit breaker on the grid side and the CT detection data of the second circuit breaker on the grid side; the second detection data includes the CT detection data of the high voltage side of the first transformer substation; and the third detection data includes the CT detection data of one branch of the low voltage side of the transformer substation and the CT detection data of the second branch of the low voltage side of the transformer substation. The first experimental results for determining the high-voltage side of the main transformer, the low-voltage side of the main transformer, the high-voltage side of the plant service transformer, and the low-voltage side of the plant service transformer based on the first detection data, the second detection data, and the third detection data include: The polarity consistency result of the first CT on the low-voltage side of the power grid to the plant transformer is determined based on the CT detection data of the first circuit breaker on the grid side, the CT detection data of the second circuit breaker on the grid side, the CT detection data of the first high-voltage side of the plant transformer, the CT detection data of one branch of the low-voltage side of the plant transformer, and the CT detection data of the second branch of the low-voltage side of the plant transformer. The differential current result of the main transformer differential protection is determined based on the CT detection data of the first circuit breaker on the grid side, the CT detection data of the second circuit breaker on the grid side, and the CT detection data of the high voltage side of the first substation transformer. The differential current result of the transformer differential protection is determined based on the CT detection data of the first high-voltage side of the transformer, the CT detection data of one branch of the low-voltage side of the transformer, and the CT detection data of the second branch of the low-voltage side of the transformer. The first experimental result is obtained based on the first CT polarity consistency result, the main transformer differential protection differential current result, and the plant transformer differential protection differential current result.

[0009] According to some embodiments of the present invention, the fourth detection data includes CT detection data on the generator output side; the fifth detection data includes CT detection data on the high-voltage side of the second substation. The second experimental results for determining the generator output side and the high-voltage side of the plant service transformer based on the fourth and fifth detection data include: Based on the CT detection data of the generator output side and the CT detection data of the second transformer high voltage side, the polarity consistency result of the second CT on the generator output side and the transformer high voltage side is determined, and the second experimental result is obtained.

[0010] According to some embodiments of the present invention, determining the short-circuit test result based on the first experimental result and the second experimental result includes: The final CT polarity consistency result of the generator plant is determined based on the first CT polarity consistency result and the second CT polarity consistency result; The short-circuit test results are obtained based on the final CT polarity consistency results, the main transformer differential protection differential current results, and the plant transformer differential protection differential current results.

[0011] According to some embodiments of the present invention, the fourth detection data further includes generator-side voltage lead current angle information; The generator plant short-circuit test method also includes: The demagnetization result, out-of-step result, and reverse power result are determined based on the generator-side voltage lead current angle information.

[0012] According to some embodiments of the present invention, the auxiliary load is plant equipment.

[0013] According to a second aspect of the present invention, a generator plant short-circuit test system is provided, wherein the generator in the generator plant has an output circuit breaker on the output side of the generator, and the generator is connected to the main transformer and the plant service transformer through the output circuit breaker; The generator plant short-circuit test system includes: The first detection module is used to control the outlet circuit breaker to open; control the main transformer to transmit power from the grid to the high-voltage side of the plant transformer, and start the auxiliary load so that the plant transformer and the main transformer can operate under load; and collect the first detection data of the CT detection point on the high-voltage side of the main transformer, the second detection data of the CT detection point on the high-voltage side of the plant transformer, and the third detection data of the CT detection point on the low-voltage side of the plant transformer. The second detection module is used to disconnect the main transformer from the power grid and close the output circuit breaker; when the first branch of the low-voltage side of the plant transformer is short-circuited, it acquires the fourth detection data of the CT detection point on the output side of the generator and the fifth detection data of the CT detection point on the high-voltage side of the plant transformer. The result output module is used to determine the short-circuit test results of the generator plant based on the first detection data, the second detection data, the third detection data, the fourth detection data, and the fifth detection data.

[0014] The generator plant short-circuit test system according to embodiments of the present invention has at least the following beneficial effects: The generator plant short-circuit test system of this invention utilizes the generator's output circuit breaker to actively disconnect the generator. This avoids damage to the generator when backfeeding power from the main transformer to the generator plant. Ultimately, it can complete the inspection of CT polarity detection on both sides of the main transformer and both sides of the auxiliary transformer under the premise of backfeeding operation. Furthermore, with the generator output circuit breaker closed, a short-circuit test is performed on the first branch of the low-voltage side of the auxiliary transformer, energizing the generator side and completing the inspection of CT polarity detection on the high-voltage side of the auxiliary transformer and the generator output side. Finally, the test results can be used to determine the results of all short-circuit test requirements in the generator system. This generator plant short-circuit test system of this invention completes the short-circuit test requirements with fewer steps and eliminates the need for a grounding switch at the short-circuit point on the high-voltage side of the main transformer, thus greatly reducing test time and increasing test safety. This generator plant short-circuit test system of this invention can effectively reduce the time by more than half during actual short-circuit testing and has significant promotional value.

[0015] According to some embodiments of the present invention, the result output module is further configured to determine the demagnetization result, the step-out result, and the reverse power result based on the generator-side voltage lead current angle information.

[0016] According to a third aspect embodiment of the present invention, a computer-readable storage medium stores computer-executable instructions for performing the generator short-circuit test method as described in the first aspect embodiment. Since the computer-readable storage medium employs all the technical solutions of the generator short-circuit test method of the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments.

[0017] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a diagram showing the layout of short-circuit points during short-circuit testing at a generator factory. Figure 2 This is a CT configuration diagram of the generator and transformer units at the generator plant; Figure 3 This is a flowchart of a generator short-circuit test method according to an embodiment of the present invention.

[0019] Figure label: Generator 100, Outlet Circuit Breaker 200, Main Transformer 300, Plant Auxiliary Transformer 400, Power Grid 500, Excitation Transformer 600. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] In the description of this invention, the use of terms such as "first," "second," etc., is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or implicitly indicating the order of the technical features indicated.

[0022] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are some embodiments of the present invention, not all embodiments.

[0025] To better describe the generator plant short-circuit test method, system, and storage medium provided in the embodiments of the present invention, the system architecture of the generator plant is further introduced here, such as... Figure 1 As shown, the generator plant includes a main transformer 300, a plant service transformer 400, a generator 100, and an excitation transformer 600. The high-voltage side of the main transformer 300 is connected to different locations on the power grid 500 via two branches. The high-voltage side of the main transformer 300 is connected to the high-voltage side of the plant service transformer 400 and the output side of the generator 100. The low-voltage side of the plant service transformer 400 is connected to the first branch (the branch where K4 is located) and the second branch (the branch where K5 is located) via two sets of windings, thereby providing power to the plant service equipment. Further reference. Figure 2 , Figure 2 The diagram shows the layout of the main current transformers (CTs) in the generator plant. Figure 2 TA1 to TA8 are all CT current transformers. By obtaining the test results of the current transformers, we can use them to confirm the results of subsequent short-circuit tests, or to monitor them during actual operation in the generator plant.

[0026] To further demonstrate the advantages of the embodiments of the present invention, this is combined with the above description and Figure 1 The commonly used short-circuit test procedure is further described. For example... Figure 1 As shown, Figure 1 Five short-circuit points, K1 to K5, are set up. By conducting short-circuit tests on these five points sequentially, it can be determined whether the polarity of the current transformers (CTs) in the entire generator plant is consistent. The specific process is as follows: 1) Short-circuit test at short-circuit point K1 (output side of generator 100): A short-circuit busbar is installed on the closed busbar of generator 100 to conduct a short-circuit test on generator 100. The main purpose is to measure the secondary amplitude and phase of the neutral point CT and the output side CT of generator 100 to check whether the polarity of the differential protection CT of generator 100 is correct, and to record the short-circuit characteristic curve of generator 100 (which can be used for further performance analysis of generator 100). 2) Short-circuit test at K2 short-circuit point on the high-voltage side of the main transformer 300V: Short-circuit test is performed through the grounding switch of the side circuit breaker QF1. During this test, the short-circuit current should not be too large. The main purpose is to check the secondary amplitude and phase of the bushing CT on the high-voltage side of the main transformer 300V, check the secondary amplitude and phase of the CTs on both sides of the side circuit breaker QF1, and check whether the polarity of the CT of the differential protection of the main transformer 300V is correct. 3) Short-circuit test at K3 short-circuit point on the high-voltage side of the main transformer 300V: Short-circuit test is performed through the grounding switch of the circuit breaker QF1. The short-circuit current should not be too large. The main purpose is to check the secondary amplitude and phase of the CTs on both sides of the circuit breaker QF1, and check whether the polarity of the CT of the differential protection of the main transformer is correct. 4) Short-circuit test at K4 short-circuit point on the low-voltage side of the 400 transformer: A short circuit is achieved using a short-circuit trolley on the incoming line switch of the branch containing K4 on the low-voltage side of the 400 transformer. The main purpose is to check the secondary amplitude and phase of the CT on the high-voltage side of the 400 transformer, the secondary amplitude and phase of the CT on the branch containing K4 on the low-voltage side of the 400 transformer, and whether the polarity of the CT of the differential protection of the 400 transformer is correct. 5) Short-circuit test at K5 short-circuit point on the low-voltage side of the 400 transformer: A short circuit is achieved using a short-circuit trolley on the incoming line switch of the branch containing K5 on the low-voltage side of the 400 transformer. The main purpose is to check the secondary amplitude and phase of the CT on the branch containing K5 on the low-voltage side of the 400 transformer, and whether the polarity of the CT of the differential protection of the 400 transformer is correct. Finally, all test results are used to determine whether the polarity is consistent.

[0027] The commonly used short-circuit testing methods mentioned above have problems such as numerous short-circuit steps, long testing time, complex operation, and low safety. Therefore, this invention proposes a generator plant short-circuit testing method, system, and storage medium. It should be noted that the generator plant mentioned above is merely one framework for implementing the generator plant short-circuit testing method, system, and storage medium of this invention, and is not intended to limit the scope of protection of this invention.

[0028] Based on the aforementioned generator factory, various embodiments of this application are proposed. The embodiments of this application will be further described below with reference to the accompanying drawings.

[0029] See Figure 3 As shown, Figure 3 This is a flowchart of a generator short-circuit test method according to an embodiment of the present invention. The generator short-circuit test method includes, but is not limited to, the following steps: The circuit breaker 200 is controlled to open; the main transformer 300 is controlled to transmit the power from the grid 500 to the high-voltage side of the plant transformer 400, and the auxiliary load is started so that the plant transformer 400 and the main transformer 300 can operate under load; the first detection data of the CT detection point on the high-voltage side of the main transformer 300, the second detection data of the CT detection point on the high-voltage side of the plant transformer 400, and the third detection data of the CT detection point on the low-voltage side of the plant transformer 400 are collected; The main transformer 300 is disconnected from the power grid 500 and the output circuit breaker 200 is closed. When the first branch of the low-voltage side of the plant transformer 400 is short-circuited, the fourth detection data of the CT detection point on the output side of the generator 100 and the fifth detection data of the CT detection point on the high-voltage side of the plant transformer 400 are obtained. The short-circuit test results of the generator factory were determined based on the first, second, third, fourth, and fifth test data.

[0030] First, it should be noted that for the detection of the polarity consistency between the output CT and the neutral point CT of generator 100, the short-circuit detection method consistent with step 1) in the commonly used test method is still adopted, and this process can be completed in advance.

[0031] The main purpose of the short circuit test at K2 and K3 is to check the secondary amplitude and phase of the high-voltage side bushing CT of the main transformer 300, and to check the secondary amplitude and phase of the CTs (TA3 and TA4) on both sides of the circuit breaker, so as to check whether the polarity of the CT of the differential protection of the main transformer 300 is correct. In this embodiment of the invention, the generator 100 output side is equipped with a circuit breaker (GCB). Therefore, the power from the grid 500 side can be fed back to the plant service system through the main transformer 300. By starting auxiliary loads (such as electric feedwater pumps, induced draft fans, etc.), the main transformer 300 and the plant service transformer 400 are subjected to a certain load. This allows for the measurement of the secondary amplitude and phase of the high-voltage bushing CT of the main transformer 300, the CT (TA3) of the circuit breaker QF1, the CT (TA4) of the side circuit breaker QF1, the high-voltage side CT (TA5, TA6) of the plant service transformer 400, and the branch CTs (TA7, TA8) where the low-voltage side K4 and K5 of the plant service transformer 400 are located. This enables the determination that the secondary circuit of the generator plant's CT is correct. It also allows for the checking of the differential current of the main transformer differential protection and the plant transformer differential protection, and verification of the correct polarity of the differential protection CT. That is, in this embodiment of the invention, after the main transformer 300 is back-energized, the first detection data of the CT detection point on the high-voltage side of the main transformer 300, the second detection data of the CT detection point on the high-voltage side of the plant transformer 400, and the third detection data of the CT detection point on the low-voltage side of the plant transformer 400 are collected. This completes the verification of the correctness of the secondary circuit of the CT in the generator plant, and can also check the differential current of the main transformer differential protection and the plant transformer differential protection, and verify the correct polarity of the differential protection CT. It is understood that the first detection data (e.g., the data detected by the high-voltage side bushing CT, the CT (TA3) of the circuit breaker QF1, and the CT (TA4) of the side circuit breaker QF1), the second detection data (e.g., the data detected by the high-voltage side CT (TA5, TA6) of the plant transformer 400), and the third detection data (e.g., the data detected by the branch CT (TA7, TA8) where K4 and K5 are located on the low-voltage side of the plant transformer 400) do not only include the secondary amplitude and phase of the CT described on each side above, but can also obtain more CT-collected data according to the actual situation.

[0032] It should be noted that the CT configuration for the differential protection of the 400m transformer is typically three sets of CTs: the high-voltage side CT (TA5) of the 400m transformer, the low-voltage side A branch CT (TA7) of the 400m transformer, and the low-voltage side B branch CT (TA8) of the 400m transformer. All three sets of CTs can operate via the main transformer backfeed method, thus fully validating the differential protection of the 400m transformer. The CT configuration for the differential protection of the 300m transformer is typically four sets of CTs: the generator 100 output side CT (TA2), the high-voltage side circuit breaker QF1 CT (TA4) of the 300m transformer, the high-voltage side circuit breaker QF1 CT (TA3) of the 300m transformer, and the high-voltage side CT (TA6) of the 400m transformer. The polarity of the CT (TA4) of the side circuit breaker QF1, the CT (TA3) of the interrupt circuit breaker QF1, and the high-voltage side CT (TA6) of the plant transformer 400 can be determined by the reverse power supply method of the main transformer 300, but the polarity of the CT (TA2) on the output side of the generator 100 and the CT (TA3, TA4) on the high-voltage side of the main transformer 300 cannot be verified. By conducting a short-circuit test on any branch of the low-voltage side of the plant transformer 400 (e.g., the branch where K4 is located), the polarity of the CT (TA2) on the output side of the generator 100 and the CT (TA6) on the high-voltage side of the plant transformer 400 is verified to be correct. Since the polarity of the CT (TA6) on the high-voltage side of the plant transformer 400, the CT (TA4) on the side circuit breaker QF1, and the CT (TA3) on the circuit breaker QF1 have already been verified to be correct, this indirectly verifies the polarity of the CT (TA2) on the output side of the generator 100, and the CT (TA4) and CT (TA3) on the high-voltage side of the main transformer 300. Ultimately, the method of this embodiment of the invention eliminates the need for a short-circuit test at the K2 / K3 short-circuit point on the high-voltage side of the main transformer 300, significantly shortening the short-circuit test time.

[0033] The generator plant short-circuit test method of this invention utilizes the output circuit breaker 200 of generator 100 to actively disconnect generator 100. This avoids damage to generator 100 when the main transformer 300 controls the power grid 500 to backfeed power to the generator plant. Ultimately, under the premise of backfeed operation, the method can complete the inspection of items such as CT polarity detection on both sides of the main transformer 300 and both sides of the plant service transformer 400. Furthermore, with the output circuit breaker 200 of generator 100 closed, a short-circuit test is performed on the first branch of the low-voltage side of the plant service transformer 400, energizing one side of generator 100. This allows for the inspection of items such as CT polarity detection on the high-voltage side of the plant service transformer 400 and the output side of generator 100. Finally, the test results can be used to determine the results of all short-circuit test requirements in the generator 100 system. The generator plant short-circuit test method of this invention completes the short-circuit test requirements with fewer steps and eliminates the need for a grounding switch at the 300V high-voltage side short-circuit point of the main transformer, thereby greatly reducing test time and increasing test safety. The generator plant short-circuit test method of this invention can effectively reduce the time by more than half in actual short-circuit tests and has significant potential for widespread application.

[0034] In some embodiments, determining the short-circuit test results of the generator plant based on first detection data, second detection data, third detection data, fourth detection data, and fifth detection data includes: Based on the first test data, the second test data, and the third test data, the first experimental results of the high-voltage side of the main transformer 300, the low-voltage side of the main transformer 300, the high-voltage side of the plant service transformer 400, and the low-voltage side of the plant service transformer 400 are determined. The second experimental results for the output side of generator 100 and the high-voltage side of plant transformer 400 were determined based on the fourth and fifth test data. The short-circuit test results were determined based on the results of the first and second experiments.

[0035] The correctness of the secondary circuit of the CT in the generator plant is verified using the first, second, and third test data. The differential current of the main transformer differential protection and the plant transformer differential protection can also be checked to verify the correct polarity of the differential protection CT, thus obtaining the first experimental result. The fourth and fifth test data can verify the correct polarity of the CT (TA2) on the output side of generator 100 and the CT (TA6) on the high-voltage side of plant transformer 400, thus obtaining the second experimental result. Finally, after verifying the correct polarity of the CT (TA2) on the output side of generator 100 and the CT (TA6) on the high-voltage side of plant transformer 400, and the correct polarity of the CT (TA6) on the high-voltage side of plant transformer 400, the CT (TA4) on the side circuit breaker QF1, and the CT (TA3) on the circuit breaker QF1, are indirectly verified, thus completing the verification of the CT function in the entire generator plant system.

[0036] In some embodiments, the first detection data includes the detection data of the CT of the first circuit breaker on the grid side (e.g., the detection data of the CT (TA4) of the side circuit breaker QF1) and the detection data of the CT of the second circuit breaker on the grid side (e.g., the CT (TA3) of the circuit breaker QF1). The second detection data includes the detection data of the CT on the high voltage side of the first substation transformer (e.g., the detection data of the CT (TA5, TA6) on the high voltage side of the substation transformer 400). The third detection data includes the detection data of the CT of one branch on the low voltage side of the substation transformer (e.g., the detection data of the CT (TA7) of the branch where K4 is located) and the detection data of the CT of the second branch on the low voltage side of the substation transformer (e.g., the detection data of the CT (TA8) of the branch where K5 is located). Based on the first test data, the second test data, and the third test data, the first test results for the high-voltage side of the main transformer 300, the low-voltage side of the main transformer 300, the high-voltage side of the station service transformer 400, and the low-voltage side of the station service transformer 400 are determined, including: Based on the CT detection data of the first circuit breaker on the grid side, the CT detection data of the second circuit breaker on the grid side, the CT detection data of the high-voltage side of the first transformer, the CT detection data of one branch of the low-voltage side of the transformer, and the CT detection data of the second branch of the low-voltage side of the transformer, the polarity consistency result of the first CT on the low-voltage side of the power grid from 500 to the transformer 400 is determined. The differential current result of the main transformer differential protection is determined based on the CT detection data of the first circuit breaker on the grid side, the CT detection data of the second circuit breaker on the grid side, and the CT detection data of the high voltage side of the first substation. The differential current result of the differential protection of the transformer is determined based on the CT detection data of the high voltage side of the first transformer, the CT detection data of one branch of the low voltage side of the transformer, and the CT detection data of the second branch of the low voltage side of the transformer. The first experimental results were obtained based on the first CT polarity consistency results, the main transformer differential protection differential current results, and the plant transformer differential protection differential current results.

[0037] The CT configuration for the differential protection of the 400m transformer is typically three sets of CTs: the high-voltage side CT (TA5), the low-voltage side A branch CT (TA7), and the low-voltage side B branch CT (TA8). All three sets of CTs can operate via the main transformer's reverse power supply method, thus fully validating the differential protection for the 400m transformer. The CT configuration for the differential protection of the 300m main transformer is typically four sets of CTs: the generator 100 output side CT (TA2), the high-voltage side circuit breaker QF1 CT (TA4), the high-voltage side circuit breaker QF1 CT (TA3), and the high-voltage side CT (TA6) of the 400m transformer. After obtaining the CT detection data of the first circuit breaker on the grid side, the CT detection data of the second circuit breaker on the grid side, the CT detection data of the high-voltage side of the first transformer substation, the CT detection data of one branch of the low-voltage side of the transformer substation, and the CT detection data of the second branch of the low-voltage side of the transformer substation, it is possible to determine whether the polarity of the secondary circuit is consistent and whether the differential protection is working properly.

[0038] In some embodiments, the fourth detection data includes CT detection data on the generator output side; the fifth detection data includes CT detection data on the high-voltage side of the second substation. The second experimental results, determined based on the fourth and fifth test data, for the output side of generator 100 and the high-voltage side of plant transformer 400, include: Based on the CT detection data of the generator output side and the CT detection data of the high voltage side of the second transformer, the polarity consistency results of the second CT on the output side of generator 100 and the high voltage side of the transformer were determined, and the second experimental results were obtained.

[0039] By conducting a short-circuit test on any branch of the low-voltage side of the plant transformer 400 (such as the branch where K4 is located), the detection data of the CT on the output side of the generator and the detection data of the CT on the high-voltage side of the second plant transformer can be detected and verified, thereby verifying whether the polarity of the CT on the output side of the generator 100 is consistent with that of the CT on the high-voltage side of the plant transformer 400.

[0040] In some embodiments, determining the short-circuit test result based on the first experimental result and the second experimental result includes: The final CT polarity consistency result of the generator plant is determined based on the first CT polarity consistency result and the second CT polarity consistency result; The short-circuit test results were obtained based on the final CT polarity consistency results, the main transformer differential protection differential current results, and the plant transformer differential protection differential current results.

[0041] By conducting a short-circuit test on any branch of the low-voltage side of the plant transformer 400 (e.g., the branch where K4 is located), the polarity of the CT (TA2) on the output side of generator 100 and the CT (TA6) on the high-voltage side of plant transformer 400 is verified to be correct. Since the polarity of the CT (TA6) on the high-voltage side of plant transformer 400, the CT (TA4) on the side circuit breaker QF1, and the CT (TA3) on the circuit breaker QF1 have already been verified to be correct, this indirectly verifies the polarity of the CT (TA2) on the output side of generator 100, and the CT (TA4) on the high-voltage side of main transformer 300, and the CT (TA3) on the side circuit breaker QF1. Finally, combining the previously obtained differential current results of the main transformer differential protection and the plant transformer differential protection, the short-circuit test results are obtained.

[0042] In some embodiments, the fourth detection data also includes generator-side voltage lead current angle information; The generator factory short-circuit test method also includes: The demagnetization result, out-of-step result, and reverse power result are determined based on the generator-side voltage lead current angle information.

[0043] Traditional testing methods cannot determine the correct polarity of a directional protection CT (e.g., TA2), meaning they cannot pinpoint the specific circumstances of loss of excitation, loss of synchronism, or reverse power. In this embodiment, the plant service transformer 400 is treated as a reactor. When a short-circuit test is performed on the branch containing the low-voltage side K4 of the plant service transformer 400, the generator 100 will have voltage, and the load will show a high proportion of inductive load. By measuring the angle of the generator terminal voltage leading the current (i.e., the generator-side voltage leading current angle information), which is typically around 80°, it can be determined that the polarity of the directional protection (loss of excitation, loss of synchronism, reverse power) CT is correct, thus preventing protection malfunctions after grid connection.

[0044] In some embodiments, the auxiliary load is a plant-grade device. Using plant-grade device facilitates the conduct of experiments without requiring additional load to maintain experimental requirements.

[0045] This invention also provides a generator plant short-circuit test system, which includes: a first detection module, a second detection module, and a result output module; The first detection module is used to control the circuit breaker 200 to open; control the main transformer 300 to transmit the power from the grid 500 to the high-voltage side of the plant transformer 400, and start the auxiliary load so that the plant transformer 400 and the main transformer 300 can operate under load; and collect the first detection data of the CT detection point on the high-voltage side of the main transformer 300, the second detection data of the CT detection point on the high-voltage side of the plant transformer 400, and the third detection data of the CT detection point on the low-voltage side of the plant transformer 400. The second detection module is used to disconnect the main transformer 300 from the power grid 500 and close the output circuit breaker 200; when the first branch of the low-voltage side of the plant transformer 400 is short-circuited, it acquires the fourth detection data of the CT detection point on the output side of the generator 100 and the fifth detection data of the CT detection point on the high-voltage side of the plant transformer 400. The results output module is used to determine the short-circuit test results of the generator plant based on the first test data, the second test data, the third test data, the fourth test data, and the fifth test data.

[0046] First, it should be noted that for the detection of the polarity consistency between the output CT and the neutral point CT of generator 100, the short-circuit detection method consistent with step 1) in the commonly used test method is still adopted, and this process can be completed in advance.

[0047] The main purpose of the short circuit test at K2 and K3 is to check the secondary amplitude and phase of the high-voltage side bushing CT of the main transformer 300, and to check the secondary amplitude and phase of the CTs (TA3 and TA4) on both sides of the circuit breaker, so as to check whether the polarity of the CT of the differential protection of the main transformer 300 is correct. In this embodiment of the invention, the generator 100 output side is equipped with a circuit breaker (GCB). Therefore, the power from the grid 500 side can be fed back to the plant service system through the main transformer 300. By starting auxiliary loads (such as electric feedwater pumps, induced draft fans, etc.), the main transformer 300 and the plant service transformer 400 are subjected to a certain load. This allows for the measurement of the secondary amplitude and phase of the high-voltage bushing CT of the main transformer 300, the CT (TA3) of the circuit breaker QF1, the CT (TA4) of the side circuit breaker QF1, the high-voltage side CT (TA5, TA6) of the plant service transformer 400, and the branch CTs (TA7, TA8) where the low-voltage side K4 and K5 of the plant service transformer 400 are located. This enables the determination that the secondary circuit of the generator plant's CT is correct. It also allows for the checking of the differential current of the main transformer differential protection and the plant transformer differential protection, and verification of the correct polarity of the differential protection CT. That is, in this embodiment of the invention, after the main transformer 300 is back-energized, the first detection data of the CT detection point on the high-voltage side of the main transformer 300, the second detection data of the CT detection point on the high-voltage side of the plant transformer 400, and the third detection data of the CT detection point on the low-voltage side of the plant transformer 400 are collected. This completes the verification of the correctness of the secondary circuit of the CT in the generator plant, and can also check the differential current of the main transformer differential protection and the plant transformer differential protection, and verify the correct polarity of the differential protection CT. It is understood that the first detection data (e.g., the data detected by the high-voltage side bushing CT, the CT (TA3) of the circuit breaker QF1, and the CT (TA4) of the side circuit breaker QF1), the second detection data (e.g., the data detected by the high-voltage side CT (TA5, TA6) of the plant transformer 400), and the third detection data (e.g., the data detected by the branch CT (TA7, TA8) where K4 and K5 are located on the low-voltage side of the plant transformer 400) do not only include the secondary amplitude and phase of the CT described on each side above, but can also obtain more CT-collected data according to the actual situation.

[0048] It should be noted that the CT configuration for the differential protection of the 400m transformer is typically three sets of CTs: the high-voltage side CT (TA5) of the 400m transformer, the low-voltage side A branch CT (TA7) of the 400m transformer, and the low-voltage side B branch CT (TA8) of the 400m transformer. All three sets of CTs can operate via the main transformer backfeed method, thus fully validating the differential protection of the 400m transformer. The CT configuration for the differential protection of the 300m transformer is typically four sets of CTs: the generator 100 output side CT (TA2), the high-voltage side circuit breaker QF1 CT (TA4) of the 300m transformer, the high-voltage side circuit breaker QF1 CT (TA3) of the 300m transformer, and the high-voltage side CT (TA6) of the 400m transformer. The polarity of the CT (TA4) of the side circuit breaker QF1, the CT (TA3) of the interrupt circuit breaker QF1, and the high-voltage side CT (TA6) of the plant transformer 400 can be determined by the reverse power supply method of the main transformer 300, but the polarity of the CT (TA2) on the output side of the generator 100 and the CT (TA3, TA4) on the high-voltage side of the main transformer 300 cannot be verified. By conducting a short-circuit test on any branch of the low-voltage side of the plant transformer 400 (e.g., the branch where K4 is located), the polarity of the CT (TA2) on the output side of the generator 100 and the CT (TA6) on the high-voltage side of the plant transformer 400 is verified to be correct. Since the polarity of the CT (TA6) on the high-voltage side of the plant transformer 400, the CT (TA4) on the side circuit breaker QF1, and the CT (TA3) on the circuit breaker QF1 have already been verified to be correct, this indirectly verifies the polarity of the CT (TA2) on the output side of the generator 100, and the CT (TA4) and CT (TA3) on the high-voltage side of the main transformer 300. Ultimately, the method of this embodiment of the invention eliminates the need for a short-circuit test at the K2 / K3 short-circuit point on the high-voltage side of the main transformer 300, significantly shortening the short-circuit test time.

[0049] The generator plant short-circuit test system of this invention utilizes the output circuit breaker 200 of generator 100 to actively disconnect generator 100. This avoids damage to generator 100 when the main transformer 300 controls the power grid 500 to backfeed power to the generator plant. Ultimately, under the premise of backfeed operation, it can complete the inspection of items such as CT polarity detection on both sides of the main transformer 300 and both sides of the plant service transformer 400. Furthermore, with the output circuit breaker 200 of generator 100 closed, a short-circuit test is performed on the first branch of the low-voltage side of the plant service transformer 400, energizing one side of generator 100. This allows for the inspection of items such as CT polarity detection on the high-voltage side of the plant service transformer 400 and the output side of generator 100. Finally, the above test results can be used to determine the results of all short-circuit test requirements in the generator 100 system. The generator plant short-circuit test system of this invention completes the short-circuit test requirements with fewer steps and eliminates the need for a grounding switch at the 300V high-voltage side short-circuit point of the main transformer, thereby significantly reducing test time and increasing test safety. In actual short-circuit tests, the generator plant short-circuit test system of this invention can effectively reduce the time by more than half, and has significant potential for widespread application.

[0050] In some embodiments of the present invention, the result output module is further configured to determine the demagnetization result, the step-out result, and the reverse power result based on the generator-side voltage lead current angle information.

[0051] Traditional testing methods cannot determine the correct polarity of a directional protection CT (e.g., TA2), meaning they cannot pinpoint the specific circumstances of loss of excitation, loss of synchronism, or reverse power. In this embodiment, the plant service transformer 400 is treated as a reactor. When a short-circuit test is performed on the branch containing the low-voltage side K4 of the plant service transformer 400, the generator 100 will have voltage, and the load will show a high proportion of inductive load. By measuring the angle of the generator terminal voltage leading the current (i.e., the generator-side voltage leading current angle information), which is typically around 80°, it can be determined that the polarity of the directional protection (loss of excitation, loss of synchronism, reverse power) CT is correct, thus preventing protection malfunctions after grid connection.

[0052] Furthermore, one embodiment of the present invention provides a computer-readable storage medium storing computer-executable instructions that are executed by a processor or controller, causing the processor to perform the generator short-circuit test method described in the above embodiment, for example, performing the method described above.

[0053] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which may include computer storage media or non-transitory media and communication media or transient media. As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc DVD or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0054] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A short-circuit test method for a generator, characterized in that, The generator in the generator plant has an output circuit breaker on the output side of the generator, and the generator is connected to the main transformer and the plant service transformer through the output circuit breaker. The generator plant short-circuit test method includes: The system controls the outlet circuit breaker to open; controls the main transformer to transmit power from the grid to the high-voltage side of the plant transformer, and starts the auxiliary load so that the plant transformer and the main transformer can operate under load; and collects the first detection data of the CT detection point on the high-voltage side of the main transformer, the second detection data of the CT detection point on the high-voltage side of the plant transformer, and the third detection data of the CT detection point on the low-voltage side of the plant transformer. The main transformer is disconnected from the power grid and the outlet circuit breaker is closed; when the first branch of the low-voltage side of the plant transformer is short-circuited, the fourth detection data of the CT detection point on the output side of the generator and the fifth detection data of the CT detection point on the high-voltage side of the plant transformer are obtained. The short-circuit test results of the generator plant are determined based on the first test data, the second test data, the third test data, the fourth test data, and the fifth test data.

2. The generator short-circuit test method according to claim 1, characterized in that, The step of determining the short-circuit test results of the generator plant based on the first detection data, the second detection data, the third detection data, the fourth detection data, and the fifth detection data includes: The first experimental results of the high-voltage side of the main transformer, the low-voltage side of the main transformer, the high-voltage side of the plant service transformer, and the low-voltage side of the plant service transformer are determined based on the first detection data, the second detection data, and the third detection data. The second experimental results for the generator output side and the high-voltage side of the plant transformer are determined based on the fourth and fifth detection data. The short-circuit test results are determined based on the first and second experimental results.

3. The generator short-circuit test method according to claim 2, characterized in that, The first detection data includes the CT detection data of the first circuit breaker on the grid side and the CT detection data of the second circuit breaker on the grid side; the second detection data includes the CT detection data of the high voltage side of the first transformer substation; and the third detection data includes the CT detection data of one branch of the low voltage side of the transformer substation and the CT detection data of the second branch of the low voltage side of the transformer substation. The first experimental results for determining the high-voltage side of the main transformer, the low-voltage side of the main transformer, the high-voltage side of the plant service transformer, and the low-voltage side of the plant service transformer based on the first detection data, the second detection data, and the third detection data include: The polarity consistency result of the first CT on the low-voltage side of the power grid to the plant transformer is determined based on the CT detection data of the first circuit breaker on the grid side, the CT detection data of the second circuit breaker on the grid side, the CT detection data of the first high-voltage side of the plant transformer, the CT detection data of one branch of the low-voltage side of the plant transformer, and the CT detection data of the second branch of the low-voltage side of the plant transformer. The differential current result of the main transformer differential protection is determined based on the CT detection data of the first circuit breaker on the grid side, the CT detection data of the second circuit breaker on the grid side, and the CT detection data of the high voltage side of the first substation transformer. The differential current result of the transformer differential protection is determined based on the CT detection data of the first high-voltage side of the transformer, the CT detection data of one branch of the low-voltage side of the transformer, and the CT detection data of the second branch of the low-voltage side of the transformer. The first experimental result is obtained based on the first CT polarity consistency result, the main transformer differential protection differential current result, and the plant transformer differential protection differential current result.

4. The generator short-circuit test method according to claim 3, characterized in that, The fourth detection data includes CT detection data on the generator output side; the fifth detection data includes CT detection data on the high-voltage side of the second substation. The second experimental results for determining the generator output side and the high-voltage side of the plant service transformer based on the fourth and fifth detection data include: Based on the CT detection data of the generator output side and the CT detection data of the second transformer high voltage side, the polarity consistency result of the second CT on the generator output side and the transformer high voltage side is determined, and the second experimental result is obtained.

5. The generator short-circuit test method according to claim 4, characterized in that, Determining the short-circuit test result based on the first experimental result and the second experimental result includes: The final CT polarity consistency result of the generator plant is determined based on the first CT polarity consistency result and the second CT polarity consistency result; The short-circuit test results are obtained based on the final CT polarity consistency results, the main transformer differential protection differential current results, and the plant transformer differential protection differential current results.

6. The generator short-circuit test method according to claim 1, characterized in that, The fourth detection data also includes generator-side voltage lead current angle information; The generator plant short-circuit test method also includes: The demagnetization result, out-of-step result, and reverse power result are determined based on the generator-side voltage lead current angle information.

7. The generator short-circuit test method according to claim 1, characterized in that, The auxiliary load is plant equipment.

8. A generator plant short-circuit test system, characterized in that, The generator in the generator plant has an output circuit breaker on the output side of the generator, and the generator is connected to the main transformer and the plant service transformer through the output circuit breaker. The generator plant short-circuit test system includes: The first detection module is used to control the outlet circuit breaker to open; control the main transformer to transmit power from the grid to the high-voltage side of the plant transformer, and start the auxiliary load so that the plant transformer and the main transformer can operate under load; and collect the first detection data of the CT detection point on the high-voltage side of the main transformer, the second detection data of the CT detection point on the high-voltage side of the plant transformer, and the third detection data of the CT detection point on the low-voltage side of the plant transformer. The second detection module is used to disconnect the main transformer from the power grid and close the output circuit breaker; when the first branch of the low-voltage side of the plant transformer is short-circuited, it acquires the fourth detection data of the CT detection point on the output side of the generator and the fifth detection data of the CT detection point on the high-voltage side of the plant transformer. The result output module is used to determine the short-circuit test results of the generator plant based on the first detection data, the second detection data, the third detection data, the fourth detection data, and the fifth detection data.

9. The generator plant short-circuit test system according to claim 8, characterized in that, The result output module is also used to determine the demagnetization result, out-of-step result, and reverse power result based on the generator-side voltage lead current angle information.

10. A computer-readable storage medium, characterized in that... The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the generator plant short-circuit test method as described in any one of claims 1 to 7.

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