Current transformer current power direction determination method, device and equipment for generator

Abstract

This application relates to the field of generator testing technology, and particularly to a method, apparatus, and equipment for determining the power direction of a generator's current transformer. The method includes: short-circuiting the target side of a transformer to construct a short-circuit closed loop, wherein the short-circuit closed loop includes a generator, a current transformer, and a transformer, and a waveform recorder is connected to the loop; injecting current into the short-circuit closed loop through a zero-start current from the generator until the generator terminal current rises to a first target current; using the waveform recorder to acquire the secondary voltage at the generator terminals and the secondary current of the current transformer, calculating the actual reactive power at the generator terminals based on the secondary voltage and secondary current; and determining the power direction of the generator's current transformer based on the reference reactive power and the actual reactive power at the generator terminals. This solves the problem that the power direction of the generator's current transformer secondary current and terminal secondary voltage, as well as the limitation of impedance components, can only be tested and verified after grid connection.

Description

Technical Field

[0001] This application relates to the field of generator testing technology, and in particular to a method, apparatus and equipment for determining the current power direction of a generator current transformer. Background Technology

[0002] The current transformer of the generator is a key component for functions such as generator differential protection, excitation regulator, and electricity metering. The polarity of its secondary winding needs to be adjusted according to system requirements. For example, when the generator terminal current is used for loss of excitation and loss of synchronism protection, the secondary circuit needs to adopt reduced polarity to ensure that the power direction of the generator terminal secondary current and secondary voltage is positive. The polarity adjustment needs to be based on the orientation of the current transformer P1 and P2 to determine the secondary winding wiring. The correct determination of the power direction is the core prerequisite for the normal functioning of the transformer.

[0003] Currently, some current transformers have issues where the P1 and P2 markings do not match their actual orientation, or the polarity of the secondary winding is incorrectly defined. These problems cannot be detected through conventional short-circuit tests. Conventional short-circuit tests can only verify differential protection and cannot verify the power direction and impedance of the secondary current and voltage at the generator terminals. These issues often only surface after grid connection. Furthermore, the determination of power direction in related technologies requires the generator to be connected to the grid and under load, which can lead to the unit being forced to shut down for rectification due to unmet requirements for power direction and impedance, affecting the unit's operation. If a fault occurs at this time, the protection system may fail to operate, and the generator may be damaged. Summary of the Invention

[0004] This application provides a method, device, and equipment for determining the power direction of a generator current transformer, in order to solve the problems in related technologies where the power direction and impedance components of the generator current transformer's secondary current and terminal secondary voltage can only be tested and verified after grid connection, which can then reveal that the power direction and impedance components do not meet the requirements, affecting unit operation and damaging generator equipment.

[0005] The first aspect of this application provides a method for determining the power direction of a current transformer in a generator. The generator is connected to a transformer, and the method includes the following steps: short-circuiting the target side of the transformer to construct a short-circuit closed loop, wherein the short-circuit closed loop includes a generator, a current transformer, and a transformer, and a waveform recorder is connected to the short-circuit closed loop; injecting current into the short-circuit closed loop through a zero-start current of the generator until the generator terminal current rises to a first target current; using the waveform recorder to obtain the secondary voltage of the generator terminal and the secondary current of the current transformer, and calculating the actual reactive power of the generator terminal based on the secondary voltage and secondary current; calculating the reference reactive power of the generator terminal according to the equipment parameters in the short-circuit closed loop, and determining the power direction of the secondary current of the generator's current transformer and the secondary voltage of the generator terminal based on the actual reactive power and the reference reactive power.

[0006] Optionally, before short-circuiting the target side of the transformer, the method further includes: identifying the type of transformer; and determining the target side of the transformer based on the type of transformer.

[0007] Optionally, the target side of the transformer can be determined according to the type of the transformer, including: if the transformer is a main transformer, the target side is the high-voltage side of the main transformer; if the transformer is a high-voltage station service transformer, the target side is the low-voltage side of the high-voltage station service transformer.

[0008] Optionally, the equipment parameters include at least one of the following: the rated capacity of the transformer, the short-circuit impedance of the transformer, the first rated voltage on the high-voltage side of the transformer, the second rated voltage on the low-voltage side of the transformer, and the voltage transformer ratio at the generator terminals.

[0009] Optionally, before short-circuiting the target side of the transformer to construct a short-circuit closed loop, the method further includes: calculating a first target current and a second target current on the target side of the transformer based on a first rated voltage or a second rated voltage, and at least one of rated capacity and short-circuit impedance.

[0010] Optionally, the reference reactive power at the generator terminal is calculated based on the equipment parameters in the short-circuit closed loop, including: identifying the voltage transformer ratio at the generator terminal; and calculating the reference reactive power at the generator terminal based on the first target current, voltage transformer ratio, rated voltage, rated capacity, and short-circuit impedance.

[0011] Optionally, before short-circuiting the target side of the transformer to construct a short-circuit closed loop, the method further includes: if the transformer is a main transformer, obtaining the reference current of the grounding switch of the main transformer; if the reference current is greater than the second target current, short-circuiting the high-voltage side of the main transformer; otherwise, short-circuiting the low-voltage side of the high-voltage station service transformer; if the transformer is a high-voltage station service transformer, controlling the current on the high-voltage side of the high-voltage station service transformer to be less than the rated current of the high-voltage station service transformer, and controlling the short-circuit current of each branch on the low-voltage side of the high-voltage station service transformer to be less than the third target current.

[0012] Optionally, based on the actual reactive power and the reference reactive power, the power direction of the secondary current of the generator's current transformer and the secondary voltage at the generator terminals is determined, including: if the actual reactive power is greater than a first preset value and the deviation between the actual reactive power and the reference reactive power is less than a second preset value, then the power direction is determined to be correct; otherwise, the power direction is determined to be incorrect.

[0013] A second aspect of this application provides a device for determining the power direction of a current transformer in a generator. The generator is connected to a transformer. The device includes: a construction module for short-circuiting the target side of the transformer to construct a short-circuit closed loop, wherein the short-circuit closed loop includes a generator, a current transformer, and a transformer, and a waveform recorder is connected to the short-circuit closed loop; an injection module for injecting current into the short-circuit closed loop through a zero-start current of the generator until the generator terminal current rises to a first target current; a calculation module for using the waveform recorder to obtain the secondary voltage at the generator terminals and the secondary current of the current transformer, and calculating the actual reactive power at the generator terminals based on the secondary voltage and secondary current; and a judgment module for calculating the reference reactive power at the generator terminals based on the equipment parameters in the short-circuit closed loop, and determining the power direction of the secondary current of the generator's current transformer and the secondary voltage at the generator terminals based on the actual reactive power and the reference reactive power.

[0014] Optionally, it also includes: an identification module for identifying the type of transformer before short-circuiting the target side of the transformer; and determining the target side of the transformer based on the type of transformer.

[0015] Optionally, the identification module is further configured to: if the transformer is a main transformer, then the target side is the high-voltage side of the main transformer; if the transformer is a high-voltage station service transformer, then the target side is the low-voltage side of the high-voltage station service transformer.

[0016] Optionally, the equipment parameters include at least one of the following: the rated capacity of the transformer, the short-circuit impedance of the transformer, the first rated voltage on the high-voltage side of the transformer, the second rated voltage on the low-voltage side of the transformer, and the voltage transformer ratio at the generator terminals.

[0017] Optionally, it further includes: a first calculation module for calculating a first target current and a second target current on the target side of the transformer based on a first rated voltage or a second rated voltage, and at least one of rated capacity and short-circuit impedance, before short-circuiting the target side of the transformer to construct a short-circuit closed loop.

[0018] Optionally, the calculation module is further used to: identify the voltage transformer ratio at the generator terminals; and calculate the reference reactive power at the generator terminals based on the first target current, voltage transformer ratio, rated voltage, rated capacity, and short-circuit impedance.

[0019] Optionally, it also includes: a control module, used to, before short-circuiting the target side of the transformer to construct a short-circuit closed loop, if the transformer is a main transformer, obtain the reference current of the grounding switch of the main transformer, and short-circuit the high-voltage side of the main transformer when the reference current is greater than the second target current; otherwise, short-circuit the low-voltage side of the high-voltage station service transformer; if the transformer is a high-voltage station service transformer, control the current on the high-voltage side of the high-voltage station service transformer to be less than the rated current of the high-voltage station service transformer, and control the short-circuit current of each branch on the low-voltage side of the high-voltage station service transformer to be less than the third target current.

[0020] Optionally, the judgment module is further configured to: if the actual reactive power is greater than the first preset value, and the deviation between the actual reactive power and the reference reactive power is less than the second preset value, then the power direction is judged to be correct; otherwise, the power direction is judged to be incorrect.

[0021] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the program to perform the current power direction determination method for a current transformer of a generator as described in the above embodiments.

[0022] Therefore, this application has at least the following beneficial effects: When a short-circuit test is performed on one side of the transformer connected to the generator, the transformer's short-circuit impedance is relatively large, and a certain voltage will be generated at the generator terminals. When the voltage exceeds a certain amplitude, the waveform recorder can sample it correctly. Since the transformer is an inductive load, the sampled voltage and the short-circuit current have a 90° angle difference. Therefore, the waveform recorder can calculate and display the generator's reactive power at this time. Thus, this application can short-circuit the target side of the transformer and inject short-circuit current. At the same time, the secondary circuit of the generator current transformer used for loss of excitation and loss of synchronism, as well as the secondary voltage at the generator terminals, are connected to the waveform recorder. This allows the waveform recorder to calculate the actual reactive power at the generator terminals based on the secondary voltage and secondary current. Then, based on the reference reactive power and the actual reactive power, the power direction of the secondary current of the generator's current transformer and the secondary voltage at the generator terminals can be determined. This eliminates the need to perform the test after the generator is connected to the grid, avoiding the problem of immediate shutdown and rectification due to unmet requirements for power direction and impedance components, thus preventing damage to the generator. At the same time, impedance-type protections such as power protection, loss of excitation, and loss of synchronism can be put into operation before the generator set is connected to the grid, ensuring safer and more reliable operation of the generator set. This solves the technical problem in related technologies that the power direction and impedance components of the generator current transformer secondary current and the generator terminal secondary voltage can only be tested and verified after grid connection, which can then reveal that the power direction and impedance components do not meet the requirements, affecting the operation of the unit and damaging the generator equipment.

[0023] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0024] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of a generator current transformer current power direction determination method according to an embodiment of this application; Figure 2 This is an example diagram of a current transformer current power direction determination device for a generator provided according to an embodiment of this application; Figure 3 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. Detailed Implementation

[0025] The embodiments of this application 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 intended to explain this application, and should not be construed as limiting this application.

[0026] Before describing the solution of this application, the relevant technologies of this application will be described first to help to understand the solution of this application.

[0027] Generator current transformers are divided into neutral point current transformers and generator terminal current transformers. They are mainly used for generator differential protection, excitation regulators, electricity metering, and measurement. Depending on the requirements of each system, the polarity of the secondary winding of the current transformer needs to be adjusted. For example, if the generator terminal current is used for generator loss of excitation and loss of synchronism protection, the secondary circuit of the current transformer should adopt "reduced polarity", that is, the current directions of the primary and secondary windings are the same, and the power direction of the generator terminal secondary current and generator terminal secondary voltage is "positive".

[0028] In infrastructure commissioning or renovation projects, the orientation of current transformers P1 and P2 is required to determine the wiring of the secondary windings. For example, if a generator-terminal current transformer is used for loss of excitation and loss of synchronism protection, and P1 points towards the generator, then when determining the secondary winding wiring, the S1 terminal of the secondary winding should be used as phases A, B, and C, while the S2 terminal should be used as phase N. Currently, the conventional method for commissioning and renovation is to verify whether the secondary current of the current transformer meets the differential protection requirements through a short-circuit test during the start-up of the entire electrical system, and to verify whether the phase sequence and amplitude of the secondary current of the current transformer are correct. However, for impedance-type protection such as loss of excitation, loss of synchronism, and reverse power, the power direction can only be determined by the angle between voltage and current after grid connection. However, some generator neutral point and terminal current transformers at the field have a problem where the P1 and P2 markings do not match the actual direction. This causes the power direction and impedance of the secondary current and terminal voltage of the current transformer to fail to meet the requirements of the field equipment. The conventional short-circuit test method cannot detect this problem (i.e., the conventional short-circuit test method can only verify differential protection, not power direction and impedance). It can only be discovered after grid connection and load. There have been many cases where the generator unit has been forced to shut down for processing because the power direction and impedance of the secondary current and secondary voltage cannot meet the requirements of field protection, electricity metering and automation equipment after grid connection.

[0029] Therefore, this application provides a method for determining the power direction of the current transformer in a generator. The power direction can be tested during a short-circuit test, without having to wait until the generator is connected to the grid. This avoids the problem of having to immediately shut down the generator for rectification if the power direction of the secondary current of the current transformer and the secondary voltage at the generator terminals, as well as the impedance components, do not meet the requirements. At the same time, it can also activate impedance-type protections such as power protection, loss of excitation, and loss of synchronism before the generator is connected to the grid, ensuring that the generator set can operate more safely and reliably.

[0030] Specifically, Figure 1 This is a flowchart illustrating a method for determining the current power direction of a generator's current transformer, provided in an embodiment of this application.

[0031] like Figure 1 As shown, the method for determining the current power direction of the current transformer of the generator includes the following steps S101 to S104.

[0032] The generator in this application is connected to a transformer.

[0033] In step S101, the target side of the transformer is short-circuited to construct a short-circuit closed loop. The short-circuit closed loop includes a generator, a current transformer, and a transformer. A waveform recorder is connected to the short-circuit closed loop.

[0034] Among them, the current transformers are the neutral point current transformers and the generator terminal current transformers, which are mainly used for generator differential protection, excitation regulators, electricity metering, and measurement, ensuring that the polarity and power direction of the secondary windings meet the requirements; the target side is the short-circuit end of the selected transformer, which can be selected as the high-voltage side or the low-voltage side depending on the type of transformer; the short-circuit closed loop is the current flow loop composed of the generator, current transformers, and transformers, which is the basic loop for short-circuit testing; the waveform recorder is a test device used to collect the secondary voltage of the generator terminals and the secondary current of the current transformers, and to calculate the actual reactive power.

[0035] In step S102, current is injected into the short-circuit closed loop through the generator zero-start flow until the generator terminal current rises to the first target current.

[0036] The first target current is the minimum short-circuit current that the generator terminal needs to reach, because reaching the first target current is sufficient to meet the secondary voltage requirements of the waveform recorder for sampling.

[0037] It is understood that, in the embodiments of this application, current can be injected into the short-circuit closed loop through the generator zero-start flow until the generator terminal current rises to the first target current, so that the waveform recorder can sample the secondary voltage of the generator terminal.

[0038] In step S103, the secondary voltage at the generator terminal and the secondary current of the current transformer are obtained using a waveform recorder, and the actual reactive power at the generator terminal is calculated based on the secondary voltage and secondary current.

[0039] When a short-circuit test is performed on the target side of the transformer connected to the generator, the transformer's short-circuit impedance is relatively large, and a certain voltage will be generated at the generator terminals. When the voltage exceeds a certain amplitude, the waveform recorder can sample it correctly. Since the transformer is an inductive load, the sampled voltage and the short-circuit current have a 90° angle difference. Therefore, the waveform recorder can calculate and display the reactive power of the generator at this time. Thus, in this embodiment, the secondary circuit of the generator current transformer used for loss of excitation and loss of synchronism and the secondary voltage at the generator terminals can be connected to the waveform recorder so that the waveform recorder can calculate the actual reactive power at the generator terminals based on the secondary voltage and secondary current, which facilitates subsequent judgment on whether the power direction is correct.

[0040] In step S104, the reference reactive power at the generator terminal is calculated based on the equipment parameters in the short-circuit closed loop, and the power direction of the secondary current of the generator current transformer and the secondary voltage at the generator terminal is determined based on the actual reactive power and the reference reactive power.

[0041] Among them, the reference reactive power is the reactive power at the generator terminal calculated based on the equipment parameters of the transformer and generator, which is used to determine whether the actual power direction is correct; the power direction is the phase correspondence between the secondary current of the generator current transformer and the secondary voltage at the generator terminal.

[0042] It is understood that the embodiments of this application can calculate the reference reactive power at the generator terminal based on the equipment parameters in the short-circuit closed loop, and determine the power direction of the secondary current of the generator's current transformer and the secondary voltage at the generator terminal based on the actual reactive power and the reference reactive power. The power direction can be tested through a short-circuit test to determine whether it is correct, without having to test after the generator is connected to the grid. This avoids the problem of needing to immediately shut down for rectification due to the power direction and impedance components not meeting the requirements, thus avoiding damage to the generator. At the same time, impedance-type protections such as power protection, loss of excitation, and loss of synchronism can be put into operation before the generator set is connected to the grid, ensuring that the generator set can operate more safely and reliably.

[0043] In one embodiment of this application, before short-circuiting the target side of the transformer, the method further includes: identifying the type of transformer; and determining the target side of the transformer based on the type of transformer.

[0044] It is understood that the embodiments of this application can identify the type of transformer and determine the target side of the transformer based on the type of transformer in order to avoid test failure caused by incorrect selection of the target side.

[0045] In one embodiment of this application, determining the target side of the transformer based on the type of transformer includes: if the transformer is a main transformer, then the target side is the high-voltage side of the main transformer; if the transformer is a high-voltage station service transformer, then the target side is the low-voltage side of the high-voltage station service transformer.

[0046] Among them, the main transformer connects the generator to the power grid to realize voltage step-up. The high-voltage side of the main transformer is the side connected to the power grid and is the high-voltage output terminal; the high-voltage plant service transformer is used for power plant power supply and is mostly a double-split transformer, containing two low-voltage branches.

[0047] It is understood that in the embodiments of this application, when the transformer is identified as a main transformer, the target side is the high-voltage side of the main transformer; when the transformer is identified as a high-voltage station service transformer, the target side is the low-voltage side of the high-voltage station service transformer, thus avoiding the failure of the short-circuit test.

[0048] In one embodiment of this application, the equipment parameters include at least one of the following: the rated capacity of the transformer, the short-circuit impedance of the transformer, the first rated voltage on the high-voltage side of the transformer, the second rated voltage on the low-voltage side of the transformer, and the voltage transformer ratio at the generator terminals.

[0049] In one embodiment of this application, before short-circuiting the target side of the transformer to construct a short-circuit closed loop, the method further includes: calculating a first target current and a second target current on the target side of the transformer based on a first rated voltage or a second rated voltage, and at least one of rated capacity and short-circuit impedance.

[0050] The second target current is the minimum short-circuit current on the target side of the transformer. When the current rises to this level, the generator terminal can generate a secondary voltage that meets the sampling requirements of the waveform recorder.

[0051] It is understood that the embodiments of this application can calculate the first target current and the second target current on the target side of the transformer based on the first rated voltage or the second rated voltage, as well as the rated capacity and short-circuit impedance. Calculating the first target current and the second target current facilitates the sampling of the waveform recorder and avoids the waveform recorder being unable to sample due to the current being too small.

[0052] Specifically, the calculation methods for the first target current and the second target current of different transformers in this application embodiment are as follows: 1. Main transformer.

[0053] The first target current (generator terminal short-circuit current) is: ; in, The first target current, The rated capacity of the main transformer, The short-circuit impedance of the main transformer. The rated voltage on the low-voltage side (i.e., the generator terminal) of the main transformer is the second rated voltage.

[0054] The second target current (short-circuit current on the high-voltage side of the main transformer) is: ; in, This refers to the rated voltage on the high-voltage side of the main transformer, also known as the first rated voltage.

[0055] 2. High-voltage plant service transformers.

[0056] The first target current (generator terminal short-circuit current) is: ; in, The first target current, This refers to the rated capacity of the high-voltage plant service transformer. For half-through impedance, This refers to the rated voltage on the high-voltage side (i.e., the generator end) of the high-voltage plant service transformer; Second target current (current in each branch on the low-voltage side of the high-voltage plant service transformer): ; in, For the second target current, This refers to the rated voltage on the low-voltage side of the high-voltage plant service transformer.

[0057] In one embodiment of this application, calculating the reference reactive power at the generator terminal based on the equipment parameters in the short-circuit closed loop includes: identifying the voltage transformer ratio at the generator terminal; and calculating the reference reactive power at the generator terminal based on the first target current, the voltage transformer ratio, the rated voltage, the rated capacity, and the short-circuit impedance.

[0058] It is understood that the embodiments of this application can identify the voltage transformer ratio at the generator terminal; and calculate the reference reactive power at the generator terminal based on the first target current, voltage transformer ratio, rated voltage, rated capacity and short-circuit impedance.

[0059] Specifically, the formula for calculating the reference reactive power in this application embodiment is as follows: 1. When the transformer is the main transformer, ; in, For reference reactive power, This is the secondary voltage at the generator terminals. The voltage transformer ratio at the generator terminals. The first target current, The second rated voltage on the low-voltage side of the main transformer. The rated capacity of the main transformer.

[0060] 2. When the transformer is a high-voltage station service transformer, ; in, This is the secondary voltage at the generator terminals. This refers to the rated capacity of the high-voltage plant service transformer.

[0061] Specifically, the waveform recorder in this application embodiment has certain amplitude requirements for voltage sampling. Only when the voltage is greater than a certain amplitude can the waveform recorder sample correctly. After researching and using waveform recorders from multiple brands, it was found that when the line voltage is greater than 3V, the sampling accuracy requirements of the waveform recorder can be met. The angle sampling of the current is also basically consistent with the theory and can also correctly display the reactive power. Therefore, in specific tests, it should be ensured that the secondary voltage generated at the generator end by the transformer short-circuit impedance is greater than 3V. The relevant setting values ​​and the calculation process of the reference reactive power involved in the short circuit on the high-voltage side of the main transformer and the short circuit on the low-voltage side of the high-voltage plant transformer are as follows.

[0062] 1. Short-circuit current requirements and voltage and reactive power calculations when the high-voltage side of the main transformer (hereinafter referred to as the main transformer) is short-circuited.

[0063] Set the rated capacity of the main transformer The unit is MVA; the rated voltage on the high-voltage side is The unit is kV; the short-circuit impedance of the main transformer is The rated voltage at the generator terminal (low-voltage side of the main transformer) is The unit is kV.

[0064] The rated current of the high-voltage side of the main transformer is The unit is kA.

[0065] When the generator short-circuit current rises to When the voltage is high, the current on the main transformer high-voltage side is: ; The per-unit value of the secondary voltage generated at the terminal at this time is... ; To make Then the per-unit value should satisfy ,Right now , During calculation, the actual short-circuit current of the generator is... The unit should be kA.

[0066] When the current is increased, the generator terminal short-circuit circuit should meet the following requirements: ; The short-circuit current on the high-voltage side of the main transformer should meet the requirements. ; The theoretical calculated value of the generator's reactive power at this time is: .

[0067] in, The voltage transformer ratio at the generator terminals. The calculated unit is kVar.

[0068] Currently, most of the step-up substations in newly built power plant projects are GIS (Gas Insulated Switchgear). When conducting short-circuit tests on the high-voltage side of the main transformer, it is not possible to install a short-circuit line. The test is usually conducted by closing the grounding switch of the step-up substation. However, if the test current is too large, it may damage the contacts of the grounding switch. Local power grid dispatching departments generally do not allow the test current to be too large. Therefore, in some test sites, due to the small test current, the secondary voltage generated at the generator terminal cannot reach 3V. If 3V cannot be reached, it is necessary to conduct the test by short-circuiting the low-voltage side of the high-voltage station service transformer.

[0069] 2. Short-circuit current requirements and voltage and reactive power calculations for low-voltage side short circuits of high-voltage plant service transformers (hereinafter referred to as high-voltage plant transformers).

[0070] The rated capacity of the high-voltage transformer is set as follows: The unit is MVA; the rated voltage on the high-voltage side (generator terminal) of the high-voltage transformer is... The unit is kV; the rated voltage on the low-voltage side is The unit is kV; high-voltage transformers are generally double-split transformers (i.e., there are two branches on the low-voltage side), and the half-pass-through impedance is set to... When both branches on the low-voltage side are short-circuited, the total through-impedance is... .

[0071] The rated current of the high-voltage side of the transformer is The unit is kA.

[0072] When the generator short-circuit current rises to At that time, the high-voltage side current of the transformer is equal to the short-circuit current at the generator terminals. .

[0073] The current in each branch on the low-voltage side is ; The per-unit value of the secondary voltage generated at the terminal at this time is... ; To make Then the per-unit value should satisfy ,Right now ; During calculation, the actual short-circuit current of the generator is... The unit should be kA.

[0074] When the current is increased, the generator terminal short-circuit circuit should meet the following requirements: ; The current in each branch on the low-voltage side of the high-voltage transformer should meet the following requirements. ; The theoretical calculated value of the generator's reactive power at this time is: .

[0075] in, The voltage transformer ratio at the generator terminals. The calculated unit is kVar.

[0076] In one embodiment of this application, before short-circuiting the target side of the transformer to construct a short-circuit closed loop, the method further includes: if the transformer is a main transformer, obtaining the reference current of the grounding switch of the main transformer; if the reference current is greater than the second target current, short-circuiting the high-voltage side of the main transformer; otherwise, short-circuiting the low-voltage side of the high-voltage station service transformer; if the transformer is a high-voltage station service transformer, controlling the current on the high-voltage side of the high-voltage station service transformer to be less than the rated current of the high-voltage station service transformer, and controlling the short-circuit current of each branch on the low-voltage side of the high-voltage station service transformer to be less than the third target current.

[0077] Among them, the reference current of the grounding switch is the maximum withstand current of the grounding switch of the main transformer, that is, the maximum short-circuit current that the grounding switch can safely withstand. Exceeding this current will damage the grounding switch contacts. The third target current is the maximum withstand current of the short-circuit busbar and short-circuit trolley on the low-voltage side of the high-voltage plant service transformer, that is, the maximum current that the short-circuit busbar and short-circuit trolley can safely withstand when the low-voltage side branch is short-circuited. Exceeding this current will damage the short-circuit equipment.

[0078] It is understood that, in this application embodiment, the main transformer can be preferentially selected for short-circuit testing, while obtaining the reference current of the grounding switch. Only when the reference current is greater than the second target current will the high-voltage side of the main transformer be short-circuited to avoid equipment damage caused by the short-circuit current exceeding the withstand capacity of the grounding switch. Otherwise, when the reference current is less than or equal to the second target current, a high-voltage station service transformer is used instead, and its low-voltage side is short-circuited. Furthermore, when using a high-voltage station service transformer for short-circuiting, the current on the high-voltage side of the high-voltage station service transformer is less than the rated current of the high-voltage station service transformer, and the short-circuit current of each branch on the low-voltage side of the high-voltage station service transformer is controlled to be less than the third target current to protect the high-voltage station service transformer body and the low-voltage side short-circuit equipment and avoid the risk of equipment damage during the short-circuit process.

[0079] Specifically, the power direction determination in this application includes two methods: short-circuiting the high-voltage side of the generator main transformer and short-circuiting the low-voltage side of the high-voltage station service transformer. Generally, short-circuiting the high-voltage side of the generator main transformer is preferred because this method results in a larger reactive power value from the generator, allowing for more accurate sampling of reactive power by the waveform recorder. However, this method requires the high-voltage side short-circuit current of the main transformer to reach a certain value to meet the requirement that the secondary voltage at the generator terminals be greater than 3V. The maximum current that the grounding switch can withstand may not be reached, and excessive current may damage the grounding switch contacts. If the high-voltage side short-circuit method of the generator main transformer meets the requirements, the low-voltage side short-circuit method of the high-voltage station service transformer can be used. Based on actual test results from multiple sites, this method generally ensures that the secondary voltage at the generator terminals is greater than 3V. However, when using this method, it is important to ensure that the high-voltage side current of the high-voltage station service transformer is within acceptable limits. The short-circuit current should be lower than the rated current of the high-voltage plant transformer, and the short-circuit current of each branch on the low-voltage side should be lower than the current value that the short-circuit bus or short-circuit trolley can withstand.

[0080] In one embodiment of this application, determining the power direction of the secondary current of the generator's current transformer and the secondary voltage at the generator terminals based on the actual reactive power and the reference reactive power includes: if the actual reactive power is greater than a first preset value and the deviation between the actual reactive power and the reference reactive power is less than a second preset value, then the power direction is determined to be correct; otherwise, the power direction is determined to be incorrect.

[0081] The first preset value can be set to 0; the second preset value is the allowable deviation between the actual reactive power and the reference reactive power, which can be set according to the specific situation, and there is no specific limitation on it.

[0082] It is understood that in the embodiments of this application, if the actual reference reactive power is greater than a first preset value and the deviation between the actual reactive power and the reference reactive power is less than a second preset value, then the power direction is determined to be correct; otherwise, the power direction is determined to be incorrect. Through dual determination, the power direction is ensured to be positive, and the amplitude and phase of the current and voltage are matched, thus comprehensively verifying the correctness of the secondary circuit of the current transformer.

[0083] Furthermore, it should be noted that, in the embodiments of this application, if the direction of the secondary current power of the aforementioned terminal current transformer is correct, other secondary current tests can be performed using this set of currents as a reference.

[0084] The following describes the experimental process of the generator current transformer current power direction determination method according to a specific embodiment of this application, including: Step 1: When the high-voltage side of the generator main transformer (hereinafter referred to as the main transformer) is short-circuited, calculate the voltage and current: Main transformer rated capacity Rated voltage on the high-voltage side Main transformer short-circuit impedance First, calculate the voltage at the machine terminals to be greater than 3V, then according to the formula... Minimum short-circuit current value on the high-voltage side of the main transformer It should be: .

[0085] Then confirm whether the maximum current that the grounding switch can withstand is greater than [the specified value]. If the maximum current it can withstand is greater than Then, the direction of power and impedance of the secondary current of the generator current transformer and the secondary voltage at the generator terminal can be tested by short-circuiting the high-voltage side of the generator transformer set.

[0086] according to Calculate the terminal current value required during the short-circuit test. , .

[0087] When the generator terminal current rises to At this time, due to the short-circuit impedance of the main transformer, the secondary voltage generated at the generator terminals is 3V, that is... The primary voltage generated at the machine terminal is ,in, This refers to the voltage transformer ratio at the generator terminals.

[0088] Then the reactive power at the generator terminal is: .

[0089] Step 2: Connect the generator terminal voltage and the secondary current of a set of current transformers used for loss of excitation and loss of synchronism protection to the waveform recorder. After meeting the conditions for short-circuit testing of the generator-transformer unit, gradually increase the current to make the generator short-circuit current... The current rises to the level in formula (8). The waveform recorder records the terminal voltage, current, and reactive power at this time. The voltage sampled by the waveform recorder at this time should be 3V, and the current should be equal to the value in formula (8). The current in the waveform recorder is consistent with the formula, and the reactive power calculated in the waveform recorder is consistent with the formula. If the current is consistent with the value of the current transformer, it indicates that the secondary current circuit of the current transformer is correct and that the power direction and impedance components of the secondary voltage at the generator terminal meet the requirements. Then, using the current transformer as a reference, the amplitude and angle of the other secondary windings of the generator current transformer are tested.

[0090] As shown in step 1, after calculation, the maximum current that the grounding switch can withstand is lower than the formula. If the high-voltage side current of the main transformer is low, then the low-voltage side short circuit test should be performed using the high-voltage plant service transformer (hereinafter referred to as the high-voltage plant transformer) in steps 3 and 4.

[0091] Step 3: During the short-circuit test on the low-voltage side of the high-voltage transformer, the voltage and current are calculated by simultaneously short-circuiting two branches on the low-voltage side of one high-voltage transformer: High-voltage transformer rated capacity. The rated voltage of the high-voltage side (generator terminal) of the high-voltage transformer is: The rated voltage on the low-voltage side is Half-cross impedance First, calculate the voltage at the machine terminals to be greater than 3V, then according to the formula... Minimum short-circuit current value on the high-voltage side of the high-voltage transformer It should be: .

[0092] At this time, the generator terminal current ; According to the formula The minimum short-circuit current for each branch on the low-voltage side of the high-voltage transformer should be: .

[0093] When the generator terminal current rises to At this time, due to the short-circuit impedance of the high-voltage transformer, the secondary voltage generated at the generator terminals is 3V, that is... The primary voltage generated at the machine terminal is ,in, This refers to the voltage transformer ratio at the generator terminals.

[0094] Then the reactive power at the generator terminal is: .

[0095] Step 4: Connect the generator terminal voltage and the secondary current of a set of current transformers used for loss of excitation and loss of synchronism protection to the waveform recorder. After meeting the conditions for short-circuit testing on the low-voltage side of the high-voltage transformer, gradually increase the current to make the generator short-circuit current... Ascend to formula The waveform recorder records the terminal voltage, current, and reactive power at this time. The voltage sampled by the waveform recorder should be 3V, and the current should be as shown in the formula. The current in the waveform recorder is consistent with the formula, and the reactive power calculated in the waveform recorder is consistent with the formula. If the current is consistent with the value of the current transformer, it indicates that the secondary current circuit of the current transformer is correct and that the power direction and impedance components of the secondary voltage at the generator terminal meet the requirements. Then, using the current transformer as a reference, the amplitude and angle of the other secondary windings of the generator current transformer are tested.

[0096] In summary, the embodiments of this application utilize the principle of short-circuiting and increasing current on one side of the transformer while generating a certain voltage on the other side due to the short-circuit impedance. During short-circuit tests on the high-voltage side of the main transformer or the low-voltage side of the high-voltage plant transformer, the generator terminal current and the generator terminal voltage generated by the transformer short-circuit impedance are connected to a waveform recorder. The reactive power is measured using the waveform recorder. If the reactive power measured by the waveform recorder is consistent with the theoretically calculated reactive power, it indicates that the secondary current power direction of the generator terminal current transformer is correct. Then, using this current as a reference, other secondary currents are tested. This solves the problem that the power direction and impedance components of the generator current transformer secondary current and generator terminal secondary voltage can only be tested and verified after grid connection. It avoids the problem of having to immediately shut down for rectification if the power direction and impedance components of the current transformer secondary current and generator terminal secondary voltage do not meet the requirements. At the same time, it can also put impedance-type protections such as power protection, loss of excitation, and loss of synchronism into operation before the unit is connected to the grid, ensuring that the generator unit can operate more safely and reliably.

[0097] According to the generator current transformer current power direction determination method proposed in this application embodiment, since the transformer short-circuit impedance is relatively large when a short-circuit test is performed on one side of the transformer connected to the generator, a certain voltage will be generated at the generator terminals. When the voltage is greater than a certain amplitude, the waveform recorder can correctly sample it. Since the transformer is an inductive load, the sampled voltage and the short-circuit current angle differ by 90°. Therefore, the waveform recorder can calculate and display the reactive power of the generator at this time. Therefore, this application can short-circuit the target side of the transformer and inject short-circuit current, while simultaneously using the secondary side of the generator current transformer used for loss of excitation and loss of synchronism... The circuit and the secondary voltage at the generator terminals are connected to a waveform recorder, which calculates the actual reactive power at the generator terminals based on the secondary voltage and secondary current. Then, based on the reference reactive power and the actual reactive power, it determines the power direction of the secondary current of the generator's current transformer and the secondary voltage at the generator terminals. This eliminates the need for testing after the generator is connected to the grid, avoiding the problem of immediate shutdown and rectification due to unmet requirements for power direction and impedance components, thus preventing damage to the generator. At the same time, impedance-type protections such as power protection, loss of excitation, and loss of synchronism can be put into operation before the generator set is connected to the grid, ensuring safer and more reliable operation of the generator set.

[0098] Next, referring to the accompanying drawings, a current transformer current power direction determination device for a generator according to an embodiment of this application is described.

[0099] Figure 2 This is a block diagram of the current transformer current power direction determination device for a generator according to an embodiment of this application.

[0100] The generator in this application is connected to a transformer.

[0101] like Figure 2As shown, the current transformer current power direction determination device 10 of the generator includes: a construction module 100, an injection module 200, a calculation module 300, and a judgment module 400.

[0102] The system comprises the following modules: Construction module 100 short-circuits the target side of the transformer to construct a short-circuit closed loop, which includes a generator, a current transformer, and a transformer, and is connected to a waveform recorder; Injection module 200 injects current into the short-circuit closed loop through the generator's zero-start current until the generator terminal current rises to the first target current; Calculation module 300 uses the waveform recorder to obtain the secondary voltage at the generator terminal and the secondary current of the current transformer, and calculates the actual reactive power at the generator terminal based on the secondary voltage and secondary current; Judgment module 400 calculates the reference reactive power at the generator terminal based on the equipment parameters in the short-circuit closed loop, and determines the power direction of the secondary current of the generator's current transformer and the secondary voltage at the generator terminal based on the actual reactive power and the reference reactive power.

[0103] In one embodiment of this application, the generator current transformer current power direction determination device 10 of this application embodiment further includes: an identification module.

[0104] The identification module is used to identify the type of transformer before short-circuiting the target side of the transformer; and to determine the target side of the transformer based on the type of transformer.

[0105] In one embodiment of this application, the identification module is further configured to: if the transformer is a main transformer, then the target side is the high-voltage side of the main transformer; if the transformer is a high-voltage station service transformer, then the target side is the low-voltage side of the high-voltage station service transformer.

[0106] In one embodiment of this application, the equipment parameters include at least one of the following: the rated capacity of the transformer, the short-circuit impedance of the transformer, the first rated voltage on the high-voltage side of the transformer, the second rated voltage on the low-voltage side of the transformer, and the voltage transformer ratio at the generator terminals.

[0107] In one embodiment of this application, the generator current transformer current power direction determination device 10 of this application embodiment further includes: a first calculation module.

[0108] The first calculation module is used to calculate a first target current and a second target current on the target side of the transformer based on a first rated voltage or a second rated voltage, and at least one of rated capacity and short-circuit impedance, before short-circuiting the target side of the transformer to construct a short-circuit closed loop.

[0109] In one embodiment of this application, the calculation module 300 is further configured to: identify the voltage transformer ratio at the generator terminal; and calculate the reference reactive power at the generator terminal based on the first target current, voltage transformer ratio, rated voltage, rated capacity, and short-circuit impedance.

[0110] In one embodiment of this application, the generator current transformer current power direction determination device 10 of this application embodiment further includes: a control module.

[0111] The control module is used to, before short-circuiting the target side of the transformer to form a short-circuit closed loop, if the transformer is a main transformer, obtain the reference current of the grounding switch of the main transformer. If the reference current is greater than the second target current, short-circuit the high-voltage side of the main transformer; otherwise, short-circuit the low-voltage side of the high-voltage station service transformer. If the transformer is a high-voltage station service transformer, control the current on the high-voltage side of the high-voltage station service transformer to be less than the rated current of the high-voltage station service transformer, and control the short-circuit current of each branch on the low-voltage side of the high-voltage station service transformer to be less than the third target current.

[0112] In one embodiment of this application, the determination module 400 is further configured to: if the actual reactive power is greater than a first preset value and the deviation between the actual reactive power and the reference reactive power is less than a second preset value, then determine that the power direction is correct; otherwise, determine that the power direction is incorrect.

[0113] It should be noted that the explanation of the above-described embodiment of the generator current transformer current power direction determination method also applies to the generator current transformer current power direction determination device of this embodiment, and will not be repeated here.

[0114] According to the generator current transformer current power direction determination device proposed in the embodiments of this application, since the transformer short-circuit impedance is relatively large when a short-circuit test is performed on one side of the transformer connected to the generator, a certain voltage will be generated at the generator terminals. When the voltage is greater than a certain amplitude, the waveform recorder can correctly sample it. Since the transformer is an inductive load, the sampled voltage and the short-circuit current angle differ by 90°. Therefore, the waveform recorder can calculate and display the reactive power of the generator at this time. Therefore, this application can short-circuit the target side of the transformer and inject short-circuit current, while simultaneously using the secondary side of the generator current transformer used for loss of excitation and loss of synchronism. The circuit and the secondary voltage at the generator terminals are connected to a waveform recorder, which calculates the actual reactive power at the generator terminals based on the secondary voltage and secondary current. Then, based on the reference reactive power and the actual reactive power, it determines the power direction of the secondary current of the generator's current transformer and the secondary voltage at the generator terminals. This eliminates the need for testing after the generator is connected to the grid, avoiding the problem of immediate shutdown and rectification due to unmet requirements for power direction and impedance components, thus preventing damage to the generator. At the same time, impedance-type protections such as power protection, loss of excitation, and loss of synchronism can be put into operation before the generator set is connected to the grid, ensuring safer and more reliable operation of the generator set.

[0115] Figure 3 This application provides a schematic diagram of the structure of an electronic device. The electronic device may include: The memory 301, the processor 302, and the computer program stored on the memory 301 and capable of running on the processor 302.

[0116] When the processor 302 executes the program, it implements the generator current transformer current power direction determination method provided in the above embodiments.

[0117] Furthermore, electronic devices also include: Communication interface 303 is used for communication between memory 301 and processor 302.

[0118] The memory 301 is used to store computer programs that can run on the processor 302.

[0119] The memory 301 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0120] If the memory 301, processor 302, and communication interface 303 are implemented independently, then the communication interface 303, memory 301, and processor 302 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, Figure 3 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0121] Optionally, in a specific implementation, if the memory 301, processor 302, and communication interface 303 are integrated on a single chip, then the memory 301, processor 302, and communication interface 303 can communicate with each other through an internal interface.

[0122] Processor 302 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0123] This application also provides a computer-readable storage medium storing a computer program or instructions thereon, which, when executed by a processor, implements the above-described method for determining the current power direction of a generator's current transformer.

[0124] This application also provides a computer program product, including a computer program or instructions, which, when executed, implement the above-mentioned method for determining the current power direction of a generator's current transformer.

[0125] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0126] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0127] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0128] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or more of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (FPGAs), field-programmable gate arrays (FPGAs), etc.

[0129] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

Claims

1. A method for determining the direction of current power in a generator's current transformer, characterized in that, The generator is connected to a transformer, and the method includes the following steps: The target side of the transformer is short-circuited to construct a short-circuit closed loop, wherein the short-circuit closed loop includes a generator, a current transformer, and a transformer, and a waveform recorder is connected in the short-circuit closed loop; Current is injected into the short-circuit closed loop through the generator zero-start flow until the generator terminal current rises to the first target current; The secondary voltage at the generator terminal and the secondary current of the current transformer are obtained using the waveform recorder, and the actual reactive power at the generator terminal is calculated based on the secondary voltage and the secondary current. The reference reactive power at the generator terminal is calculated based on the equipment parameters in the short-circuit closed loop, and the power direction of the secondary current of the generator's current transformer and the secondary voltage at the generator terminal is determined based on the actual reactive power and the reference reactive power.

2. The method for determining the current power direction of a generator's current transformer according to claim 1, characterized in that, Before short-circuiting the target side of the transformer, the method further includes: Identify the type of the transformer; The target side of the transformer is determined according to the type of the transformer.

3. The method for determining the current power direction of a generator's current transformer according to claim 2, characterized in that, Determining the target side of the transformer based on its type includes: If the transformer is a main transformer, then the target side is the high-voltage side of the main transformer; If the transformer is a high-voltage plant service transformer, then the target side is the low-voltage side of the high-voltage plant service transformer.

4. The method for determining the current power direction of a generator's current transformer according to claim 3, characterized in that, The equipment parameters include at least one of the following: the rated capacity of the transformer, the short-circuit impedance of the transformer, the first rated voltage on the high-voltage side of the transformer, the second rated voltage on the low-voltage side of the transformer, and the voltage transformer ratio at the generator terminals.

5. The method for determining the current power direction of a generator's current transformer according to claim 4, characterized in that, Before short-circuiting the target side of the transformer to construct a short-circuit closed loop, the following steps are also included: The first target current and the second target current on the target side of the transformer are calculated based on the first rated voltage or the second rated voltage, and at least one of the rated capacity and the short-circuit impedance.

6. The method for determining the current power direction of a generator's current transformer according to claim 4, characterized in that, The calculation of the reference reactive power at the generator terminal based on the equipment parameters in the short-circuit closed loop includes: Identify the voltage transformer ratio at the generator terminals; The reference reactive power at the generator terminal is calculated based on the first target current, the voltage transformer ratio, the rated voltage, the rated capacity, and the short-circuit impedance.

7. The method for determining the current power direction of a generator's current transformer according to claim 5, characterized in that, Before short-circuiting the target side of the transformer to construct a short-circuit closed loop, the following steps are also included: If the transformer is the main transformer, then obtain the reference current of the grounding switch of the main transformer. When the reference current is greater than the second target current, short-circuit the high-voltage side of the main transformer; otherwise, short-circuit the low-voltage side of the high-voltage plant service transformer. If the transformer is the high-voltage plant service transformer, then the current on the high-voltage side of the high-voltage plant service transformer is controlled to be less than the rated current of the high-voltage plant service transformer, and the short-circuit current of each branch on the low-voltage side of the high-voltage plant service transformer is controlled to be less than the third target current.

8. The method for determining the current power direction of a generator's current transformer according to claim 1, characterized in that, The step of determining the power direction of the secondary current of the generator's current transformer and the secondary voltage at the generator terminals based on the actual reactive power and the reference reactive power includes: If the actual reactive power is greater than the first preset value, and the deviation between the actual reactive power and the reference reactive power is less than the second preset value, then the power direction is determined to be correct; otherwise, the power direction is determined to be incorrect.

9. A device for determining the direction of current power in a current transformer of a generator, characterized in that, The generator is connected to a transformer, and the device includes: A construction module is used to short-circuit the target side of the transformer to construct a short-circuit closed loop, wherein the short-circuit closed loop includes a generator, a current transformer, and a transformer, and a waveform recorder is connected in the short-circuit closed loop; An injection module is used to inject current into the short-circuit closed loop through the generator zero-start flow until the generator terminal current rises to the first target current; The calculation module is used to acquire the secondary voltage at the generator terminal and the secondary current of the current transformer using the waveform recorder, and to calculate the actual reactive power at the generator terminal based on the secondary voltage and the secondary current. The judgment module is used to calculate the reference reactive power at the generator terminal based on the equipment parameters in the short-circuit closed loop, and to determine the power direction of the secondary current of the generator's current transformer and the secondary voltage at the generator terminal based on the actual reactive power and the reference reactive power.

10. An electronic device, characterized in that, include: The memory, the processor, and the computer program stored in the memory and executable on the processor, the processor executing the program to implement the generator current transformer current power direction determination method as described in any one of claims 1-8.

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