A method, system, medium, device and product for judging the rotating direction of a pumped storage unit

Abstract

This invention discloses a method, system, medium, equipment, and product for determining the rotation direction of a pumped-storage unit in the field of integrated plant automation technology. The method includes: if the rotation direction determination is being performed for the first time, the pumped-storage unit's grid-connected switch is not closed, and either the first or second condition is not met; determining the rotation direction of the pumped-storage unit based on the state of the pumped-storage unit's commutator switch at the moment the rotation direction determination command is received; if the rotation direction determination is being performed for the first time, the pumped-storage unit's grid-connected switch is not closed, and both the first and second conditions are met, or if the rotation direction determination is not being performed for the first time, and neither the first nor the second criterion is met; determining the rotation direction of the pumped-storage unit based on the current state of the pumped-storage unit's commutator switch; if the rotation direction determination is not being performed for the first time, and either the first or second criterion is met, maintaining the most recent pumped-storage unit rotation direction determination result unchanged.

Description

Technical Field

[0001] This invention relates to the field of integrated automation technology for power plants, and in particular to a method, system, medium, equipment and product for determining the rotation direction of pumped storage units. Background Technology

[0002] Pumped storage units are used in pumped storage power stations. Unlike ordinary generator sets, which can only accept power input from other forms of energy and then convert it into electrical energy, pumped storage units can accept the potential energy difference of water as power input to generate electricity; they can also input electrical energy to pump water. The rotation direction of the pumped storage unit is different in the two operating conditions of power generation and water pumping.

[0003] In relay protection devices, it is necessary to determine the rotation direction of the pumped-storage unit and adjust the phase sequence of the terminal voltage, terminal current, and neutral point current based on the determination result. The correctness of the rotation direction determination is related to the accuracy of the analog signal acquisition by the relay protection device, and also affects the judgment of the operating conditions of the pumped-storage unit, which may cause the protection logic to be erroneously opened or blocked.

[0004] In the existing technology, the relay protection device mainly determines the rotation direction of the pumped storage unit based on the position of the phase switch motor. If the phase switch motor is not in the set position, the rotation direction is determined to be the power generation direction. If the phase switch motor is in the set position, the rotation direction is determined to be the pumping direction. The phase sequence of analog quantities such as terminal voltage, terminal current, and neutral point current is adjusted accordingly.

[0005] When the position contact of the motor in the phase commutation switch malfunctions, the position collected by the relay protection device may not match the actual position, leading to an error in the determination of the rotation direction, which in turn leads to an error in the determination of the analog phase sequence, resulting in the protection logic being falsely locked or opened. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method, system, medium, equipment and product for determining the rotation direction of a pumped storage unit. This invention can avoid errors in the determination of the rotation direction caused by the unreliability of a single contact of the phase switch motor position or by abnormalities in the position of the phase switch motor. For incorrect rotation directions, the invention corrects errors by using the characteristics of voltage and current sequence components and issues alarm information, thereby further improving the reliability of the rotation direction determination.

[0007] To solve the above-mentioned technical problems, the present invention is implemented using the following technical solution:

[0008] In a first aspect, the present invention provides a method for determining the rotation direction of a pumped-storage unit, comprising:

[0009] If the first rotation direction determination is performed, the pumped-storage unit grid-connected switch is not closed, and either the first or second condition is not met, the rotation direction determination of the pumped-storage unit is performed based on the state of the pumped-storage unit's phase-changing switch at the moment the rotation direction determination command is received. The first condition is that the instantaneous value of any phase voltage at the pumped-storage unit's terminals is greater than a first preset voltage; the second condition is that the voltage is less than the second preset voltage for a continuous time T, where is the sum of the maximum values, is the difference between phase A voltage and phase B voltage before the specified time, is the difference between phase A voltage and phase C voltage before the specified time, and T is the average of all time differences. The time difference is the time difference between the most recent zero-crossing points of adjacent three-phase voltages in the same direction before the first condition is met. The moment of the first rotation direction determination is within the time interval between two adjacent shutdowns of the pumped-storage unit.

[0010] If the rotation direction determination is performed for the first time, the pumped-storage unit grid-connected switch is not closed, and both the first and second conditions are met; or if the rotation direction determination is not performed for the first time, and both the first and second criteria are not met, the rotation direction determination of the pumped-storage unit is performed based on the current state of the pumped-storage unit's phase-changing switch. The first criterion is that the third, fourth, and fifth conditions are all met; the second criterion is that the pumped-storage unit grid-connected switch is closed and the relay protection is activated; the third condition is that both the negative-sequence current and zero-sequence current at the pumped-storage unit's terminals are less than the first preset current; the fourth condition is that both the negative-sequence voltage and zero-sequence voltage at the pumped-storage unit's terminals are less than the fourth preset voltage; and the fifth condition is that the duration of the current being greater than the second preset current is greater than the first preset time, which is the maximum single-phase current in the previous cycle at the current moment.

[0011] If the rotation direction determination is not performed for the first time and the first criterion or the second criterion is satisfied, the result of the most recent pumped-storage unit rotation direction determination remains unchanged.

[0012] Optionally, when the pumped-storage unit's phase switch is in motor mode, the rotation direction is the pumping direction; when the pumped-storage unit's phase switch is not in motor mode, the rotation direction is the power generation direction.

[0013] Optionally, the average value T of all time differences is obtained by the following formula:

[0014] ,

[0015] in, This represents the time difference between the nearest zero-crossing points of adjacent phase A voltages in the same direction before the moment when the first condition is met. This represents the time difference between the nearest zero-crossing points of adjacent phase B voltages in the same direction before the moment when the first condition is met. This represents the time difference between the nearest zero-crossing points of adjacent C-phase voltages in the same direction before the moment when the first condition is met.

[0016] Optionally, if the state of the pumped storage unit's commutator switch at the moment the rotation direction determination command is received is not equal to the current state of the pumped storage unit's commutator switch, an abnormal rotation direction alarm will be issued.

[0017] Optional, when If the time interval T is consistently less than the third preset voltage, an abnormal rotation direction alarm will be issued; among which... for and Maximum value For phase A voltage and The voltage difference of phase B before time, For phase A voltage and The difference in phase C voltage before the time.

[0018] Optionally, when the first current criterion, the second current criterion, and the first current criterion are all satisfied, and the first voltage criterion, the second voltage criterion, and the first voltage criterion are all satisfied, the rotation direction of the pumped-storage unit is corrected: if the current rotation direction is the pumping direction, it is changed to the power generation direction; if the current rotation direction is the power generation direction, it is changed to the pumping direction. Specifically, the first current criterion is that the positive-sequence component and the zero-sequence component of the pumped-storage unit's terminal current are both less than the third preset current; the second current criterion is that the negative-sequence component of the pumped-storage unit's terminal current is greater than the fourth preset current; the third current criterion is that the difference between the maximum and minimum values ​​of the three-phase currents at the pumped-storage unit's terminals is less than the fifth preset current; the first voltage criterion is that the positive-sequence component and the zero-sequence component of the pumped-storage unit's terminal voltage are both less than the fifth preset voltage; the second voltage criterion is that the negative-sequence component of the pumped-storage unit's terminal voltage is greater than the sixth preset voltage; and the third voltage criterion is that the difference between the maximum and minimum values ​​of the three-phase voltages at the pumped-storage unit's terminals is less than the seventh preset voltage.

[0019] In a second aspect, the present invention provides a rotation direction determination system for pumped-storage units, including a rotation direction determination module, used for:

[0020] If, during the initial rotation direction determination, the pumped-storage unit's grid-connected switch is not closed and either the first or second condition is not met, the pumped-storage unit's rotation direction is determined based on the pumped-storage unit's phase-changing switch status at the moment the rotation direction determination command is received. The first condition is that the instantaneous voltage value of any phase at the pumped-storage unit's terminals is greater than a first preset voltage; the second condition is... The voltage is less than the second preset voltage for a continuous time T. for and Maximum value For phase A voltage and The voltage difference of phase B before time, For phase A voltage and The difference in C-phase voltage before the time, T is the average of all time differences, and the time difference is the time difference between the nearest three-phase voltage zero crossings in the same direction before the first condition is met; the moment of the first determination of the rotation direction is located within the time period between two adjacent shutdowns of the pumped-storage unit.

[0021] If the rotation direction determination is performed for the first time, the pumped-storage unit grid connection switch is not closed, and both the first and second conditions are met; or if the rotation direction determination is not performed for the first time, the first criterion is not met, and the second criterion is not met, based on the current time... The pumped-storage unit's rotation direction is determined by monitoring the commutation switch status. The first criterion is that conditions three, four, and five are all met. The second criterion is that the pumped-storage unit's grid-connected switch is closed and the relay protection is activated. The third condition is that both the negative-sequence current and zero-sequence current at the pumped-storage unit's terminals are less than a first preset current. The fourth condition is that both the negative-sequence voltage and zero-sequence voltage at the pumped-storage unit's terminals are less than a fourth preset voltage. The fifth condition is... The duration of the current exceeding the second preset current is greater than the first preset time. This represents the maximum single-phase current within the previous cycle at the current moment;

[0022] If the rotation direction determination is not performed for the first time and the first criterion or the second criterion is satisfied, the result of the most recent pumped-storage unit rotation direction determination remains unchanged.

[0023] Thirdly, the present invention provides a computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, implement the steps of the pumped-storage unit rotation direction determination method described in any of the first aspects.

[0024] Fourthly, the present invention provides a computer device, comprising:

[0025] Memory, used to store computer instructions;

[0026] A processor is configured to execute the computer instructions to implement the steps of the method for determining the rotation direction of a pumped storage unit as described in any of the first aspects.

[0027] Fifthly, the present invention provides a computer program product, including computer instructions, characterized in that, when the computer instructions are executed by a processor, they implement the steps of the pumped-storage unit rotation direction determination method described in any of the first aspects.

[0028] Compared with existing technologies, the beneficial effects achieved by this invention are as follows: Firstly, the rotation direction is determined by utilizing the difference in the phase relationship of the three-phase voltage under different rotation directions, avoiding errors in rotation direction determination caused by the unreliability of a single contact point of the commutation switch motor. Secondly, after the initial rotation direction determination, a second determination is made based on the current condition as the primary criterion and the voltage and current sequence components as auxiliary criterion, thus preventing errors in rotation direction determination caused by abnormal commutation switch motor positions throughout the entire operation of the pumped-storage unit. Thirdly, for incorrect rotation directions, error correction is performed using the characteristics of the voltage and current sequence components, and an alarm message is issued, further improving the reliability of rotation direction determination. Attached Figure Description

[0029] Figure 1 This is a schematic flowchart of the pumped storage unit rotation direction determination method provided in an embodiment of the present invention. Detailed Implementation

[0030] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments and specific features in the embodiments are detailed descriptions of the technical solution of the present application, rather than limitations thereof. In the absence of conflict, the embodiments and technical features in the embodiments can be combined with each other.

[0031] It should be noted that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0032] Example 1

[0033] This invention discloses a method for determining the rotation direction of a pumped-storage unit, with reference to... Figure 1 As shown, the specific steps include the following:

[0034] S1, if the rotation direction determination is performed for the first time, the pumped-storage unit grid-connected switch is not closed, and either the first or second condition is not met, the pumped-storage unit rotation direction is determined based on the pumped-storage unit's phase-changing switch status at the moment the rotation direction determination command is received; wherein, the first condition is that the instantaneous value of any phase voltage at the pumped-storage unit's generator terminal is greater than a first preset voltage; the second condition is... The voltage is less than the second preset voltage for a continuous time T. for and Maximum value For phase A voltage and The voltage difference of phase B before time, For phase A voltage and The difference in C-phase voltage before the time, T is the average of all time differences, and the time difference is the time difference between the nearest three-phase voltage zero crossings in the same direction before the first condition is met; the moment of the first determination of the rotation direction is located within the time period between two adjacent shutdowns of the pumped-storage unit.

[0035] S2, if the rotation direction determination is performed for the first time, the pumped-storage unit grid connection switch is not closed, and both the first and second conditions are met; or if the rotation direction determination is not performed for the first time, the first criterion is not met, and the second criterion is not met, based on the current time... The pumped-storage unit's rotation direction is determined by monitoring the commutation switch status. The first criterion is that conditions three, four, and five are all met. The second criterion is that the pumped-storage unit's grid-connected switch is closed and the relay protection is activated. The third condition is that both the negative-sequence current and zero-sequence current at the pumped-storage unit's terminals are less than a first preset current. The fourth condition is that both the negative-sequence voltage and zero-sequence voltage at the pumped-storage unit's terminals are less than a fourth preset voltage. The fifth condition is... The duration of the current exceeding the second preset current is greater than the first preset time. This represents the maximum single-phase current within the previous cycle at the current moment;

[0036] S3. If the rotation direction judgment is not performed for the first time and the first criterion or the second criterion is satisfied, the most recent rotation direction judgment result of the pumped storage unit remains unchanged.

[0037] Specifically, after the pumped-storage unit starts up, the rotation direction remains unchanged. In order to reduce the amount of calculation, in this implementation, the rotation direction is only determined once during the time period between two adjacent shutdowns of the pumped-storage unit and when the grid connection switch of the pumped-storage unit is not closed. At other times, it is only necessary to perform a second confirmation and maintain the previous determination.

[0038] This embodiment also includes a user confirmation mechanism. When a user initiates a rotation direction determination command at any time k, the state of the pumped-storage unit's commutator switch at time k is obtained for subsequent rotation direction determination. In other embodiments, the position of the commutator switch motor can also be recorded after the nth shutdown of the pumped-storage unit to facilitate subsequent rotation direction determination and verification.

[0039] In step S1, when the pumped-storage unit's phase switch is in motor mode, the rotation direction is the pumping direction; when the pumped-storage unit's phase switch is not in motor mode, the rotation direction is the power generation direction.

[0040] In this embodiment, the first preset voltage is preferably set to 10% of the rated voltage, and the second preset voltage is preferably set to 5% of the rated voltage; the average value T of all time differences is obtained by the following formula:

[0041] ,

[0042] in, This represents the time difference between the nearest zero-crossing points of adjacent phase A voltages in the same direction before the moment when the first condition is met. This represents the time difference between the nearest zero-crossing points of adjacent phase B voltages in the same direction before the moment when the first condition is met. This represents the time difference between the nearest zero-crossing points of adjacent C-phase voltages in the same direction before the moment when the first condition is met.

[0043] This embodiment also includes an anomaly detection mechanism. Normally, the state of the pumped-storage unit's commutator switch at the moment the instruction to determine the rotation direction is received should be the same as the current state. The states of the pumped-storage unit's commutator switches are consistent; therefore, the state of the pumped-storage unit's commutator switches at the moment the command to determine the rotation direction is received is not equal to the state at the current moment. The pumped storage unit's phase changer status is detected, triggering an abnormal rotation direction alarm to alert operators to handle the abnormality.

[0044] When the rotation direction is abnormal, the three-phase voltage at the generator terminals is a negative sequence quantity. Approaching 0, this characteristic is the main feature of abnormal rotation direction; therefore, this embodiment sets it to be close to 0. If the duration of the current voltage (T) is less than the third preset voltage, an alarm for abnormal rotation direction will be issued; among which... for and Maximum value For phase A voltage and The voltage difference of phase B before time, For phase A voltage and The difference in phase C voltage before the time, the preferred setting of the third preset voltage is 5% of the rated voltage.

[0045] In step S2, the maximum single-phase current in the previous cycle at the current time is obtained through the following steps:

[0046] Let Ias be any sampled value of the A-phase current at the current time within the previous cycle of the pumped storage unit, Ibs be any sampled value of the B-phase current at the current time within the previous cycle of the pumped storage unit, and Ics be any sampled value of the C-phase current at the current time within the previous cycle of the pumped storage unit.

[0047] Let Iam be the maximum value of |Ias|, Ibm be the maximum value of |Ibs|, and Icm be the maximum value of |Ics|.

[0048] The maximum single-phase current in the previous cycle at the current moment is the maximum value among Iam, Ibm and Icm, denoted as Im.

[0049] In this embodiment, the first preset current is preferably set to 5% of the rated current, the second preset current is preferably set to 10% of the rated current, the first preset time is preferably set to 20ms, and the fourth preset voltage is preferably set to 5% of the rated voltage.

[0050] When the unit is running normally, there will be current at the pumped-storage unit terminal, and the rotation direction will not change during normal operation. Based on this characteristic, this embodiment uses the duration of Im being greater than the second preset current being greater than the first preset time to maintain the rotation direction, so that the rotation direction will not be misjudged due to abnormality of the motor position contact of the commutation switch during operation. At the same time, in order to improve reliability, the negative sequence component and zero sequence component of the terminal voltage and current are added as auxiliary criteria.

[0051] When the relay protection is activated, the voltage or current at the pumped-storage unit terminals may have negative sequence components or zero sequence components, which may not be able to be determined by the first criterion alone. Therefore, this embodiment adds a second criterion. If neither the first criterion nor the second criterion is satisfied, the corresponding pumped-storage unit is in a shutdown state. After shutdown, the rotation direction of the pumped-storage unit may change, so it is necessary to re-determine the rotation direction.

[0052] This embodiment also includes the following rotation direction correction steps:

[0053] When the first current criterion, the second current criterion, and the first current criterion are all satisfied, and the first voltage criterion, the second voltage criterion, and the first voltage criterion are all satisfied, the rotation direction of the pumped-storage unit is corrected: if the current rotation direction is the pumping direction, it is changed to the power generation direction; if the current rotation direction is the power generation direction, it is changed to the pumping direction. Among them, the first current criterion is that the positive sequence component and the zero sequence component of the pumped-storage unit terminal current are both less than the third preset current; the second current criterion is that the negative sequence component of the pumped-storage unit terminal current is greater than the fourth preset current; the third current criterion is that the difference between the maximum and minimum values ​​of the three-phase current at the pumped-storage unit terminal is less than the fifth preset current; the first voltage criterion is that the positive sequence component and the zero sequence component of the pumped-storage unit terminal voltage are both less than the fifth preset voltage; the second voltage criterion is that the negative sequence component of the pumped-storage unit terminal voltage is greater than the sixth preset voltage; and the third voltage criterion is that the difference between the maximum and minimum values ​​of the three-phase voltage at the pumped-storage unit terminal is less than the seventh preset voltage.

[0054] In this embodiment, the third preset current is preferably set to 5% of the rated current, the fourth preset current is preferably set to 50% of the rated current, and the fifth preset current is preferably set to 5% of the rated current; the fifth preset voltage is preferably set to 5% of the rated voltage, the sixth preset voltage is preferably set to 50% of the rated voltage, and the seventh preset voltage is preferably set to 5% of the rated voltage.

[0055] In step S3.3, when the first current criterion, the second current criterion, and the first current criterion are all satisfied, and the first voltage criterion, the second voltage criterion, and the first voltage criterion are all satisfied, it means that the positive sequence component and the zero sequence component are small, the negative sequence component is large, and the three phases are symmetrical. This is the main characteristic of the rotation direction error, so the rotation direction needs to be modified.

[0056] In summary, the pumped-storage unit rotation direction determination method provided in this embodiment utilizes the differences in the three-phase voltage phase relationships under different rotation directions to confirm whether the rotation direction is correct, avoiding errors in rotation direction determination caused by the unreliability of a single contact of the commutation switch motor position. After confirming the rotation direction, the method uses the current-carrying condition as the primary criterion and the voltage and current sequence components as auxiliary criterions to maintain the rotation direction determination result. This avoids errors in rotation direction determination caused by abnormal commutation switch motor positions throughout the entire operation of the pumped-storage unit. For incorrect rotation directions, error correction is performed using the characteristics of the voltage and current sequence components, and an alarm message is issued, further improving the reliability of rotation direction determination.

[0057] Example 2:

[0058] Based on the same inventive concept as Embodiment 1, this embodiment of the invention discloses a pumped-storage unit rotation direction determination system, including a rotation direction determination module, used for:

[0059] If, during the initial rotation direction determination, the pumped-storage unit's grid-connected switch is not closed and either the first or second condition is not met, the pumped-storage unit's rotation direction is determined based on the pumped-storage unit's phase-changing switch status at the moment the rotation direction determination command is received. The first condition is that the instantaneous voltage value of any phase at the pumped-storage unit's terminals is greater than a first preset voltage; the second condition is... The voltage is less than the second preset voltage for a continuous time T. for and Maximum value For phase A voltage and The voltage difference of phase B before time, For phase A voltage and The difference in C-phase voltage before the time, T is the average of all time differences, and the time difference is the time difference between the nearest three-phase voltage zero crossings in the same direction before the first condition is met; the moment of the first determination of the rotation direction is located within the time period between two adjacent shutdowns of the pumped-storage unit.

[0060] If the rotation direction determination is performed for the first time, the pumped-storage unit grid connection switch is not closed, and both the first and second conditions are met; or if the rotation direction determination is not performed for the first time, the first criterion is not met, and the second criterion is not met, based on the current time... The pumped-storage unit's rotation direction is determined by monitoring the commutation switch status. The first criterion is that conditions three, four, and five are all met. The second criterion is that the pumped-storage unit's grid-connected switch is closed and the relay protection is activated. The third condition is that both the negative-sequence current and zero-sequence current at the pumped-storage unit's terminals are less than a first preset current. The fourth condition is that both the negative-sequence voltage and zero-sequence voltage at the pumped-storage unit's terminals are less than a fourth preset voltage. The fifth condition is... The duration of the current exceeding the second preset current is greater than the first preset time. This represents the maximum single-phase current within the previous cycle at the current moment;

[0061] If the rotation direction determination is not performed for the first time and the first criterion or the second criterion is satisfied, the result of the most recent pumped-storage unit rotation direction determination remains unchanged.

[0062] The specific functions of each module described above are explained in the relevant content of the method in Embodiment 1, and will not be repeated here.

[0063] Example 3:

[0064] This embodiment provides a computer-readable storage medium storing computer instructions thereon. When these computer instructions are executed by a processor, they implement the steps of the pumped-storage unit rotation direction determination method as described in any of the embodiments in Embodiment 1.

[0065] Example 4:

[0066] This embodiment provides a computer device, including:

[0067] Memory, used to store computer instructions;

[0068] A processor is configured to execute the computer instructions to implement the steps of the pumped storage unit rotation direction determination method as described in any one of Embodiment 1.

[0069] Example 5:

[0070] This embodiment provides a computer program product, including computer instructions, characterized in that, when the computer instructions are executed by a processor, they implement the steps of the pumped storage unit rotation direction determination method as described in any one of Embodiment 1.

[0071] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0072] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0073] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0074] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0075] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for determining the rotation direction of a pumped-storage unit, characterized in that, include: If, during the initial rotation direction determination, the pumped-storage unit's grid-connected switch is not closed and either the first or second condition is not met, the pumped-storage unit's rotation direction is determined based on the pumped-storage unit's phase-changing switch status at the moment the rotation direction determination command is received. The first condition is that the instantaneous voltage value of any phase at the pumped-storage unit's terminals is greater than a first preset voltage; the second condition is... The voltage is less than the second preset voltage for a continuous time T. for and Maximum value For phase A voltage and The voltage difference of phase B before time, For phase A voltage and The difference in C-phase voltage before the time, T is the average of all time differences, and the time difference is the time difference between the nearest three-phase voltage zero crossings in the same direction before the first condition is met; the moment of the first determination of the rotation direction is located within the time period between two adjacent shutdowns of the pumped-storage unit. If the rotation direction determination is performed for the first time, the pumped-storage unit grid connection switch is not closed, and both the first and second conditions are met; or if the rotation direction determination is not performed for the first time, the first criterion is not met, and the second criterion is not met, based on the current time... The pumped-storage unit's rotation direction is determined by monitoring the commutation switch status. The first criterion is that conditions three, four, and five are all met. The second criterion is that the pumped-storage unit's grid-connected switch is closed and the relay protection is activated. The third condition is that both the negative-sequence current and zero-sequence current at the pumped-storage unit's terminals are less than a first preset current. The fourth condition is that both the negative-sequence voltage and zero-sequence voltage at the pumped-storage unit's terminals are less than a fourth preset voltage. The fifth condition is... The duration of the current exceeding the second preset current is greater than the first preset time. This represents the maximum single-phase current within the previous cycle at the current moment; If the rotation direction determination is not performed for the first time and the first criterion or the second criterion is satisfied, the result of the most recent pumped-storage unit rotation direction determination remains unchanged.

2. The method for determining the rotation direction of a pumped-storage unit according to claim 1, characterized in that, When the pumped-storage unit's phase changer is in motor mode, the rotation direction is the pumping direction; when the pumped-storage unit's phase changer is not in motor mode, the rotation direction is the power generation direction.

3. The method for determining the rotation direction of a pumped-storage unit according to claim 1, characterized in that, The average value T of all time differences is obtained by the following formula: ， in, This represents the time difference between the nearest zero-crossing points of adjacent phase A voltages in the same direction before the moment when the first condition is met. This represents the time difference between the nearest zero-crossing points of adjacent phase B voltages in the same direction before the moment when the first condition is met. This represents the time difference between the nearest zero-crossing points of adjacent C-phase voltages in the same direction before the moment when the first condition is met.

4. The method for determining the rotation direction of a pumped-storage unit according to claim 1, characterized in that, When the command to determine the rotation direction is received, the state of the pumped-storage unit's commutator switch at that moment is not equal to the current state. The pumped storage unit's phase switching status was detected, triggering an alarm for abnormal rotation direction.

5. The method for determining the rotation direction of a pumped-storage unit according to claim 1, characterized in that, when If the time interval T is consistently less than the third preset voltage, an abnormal rotation direction alarm will be issued; among which... for and Maximum value For phase A voltage and The voltage difference of phase B before time, For phase A voltage and The difference in phase C voltage before the time.

6. The method for determining the rotation direction of a pumped-storage unit according to claim 1, characterized in that, When the first current criterion, the second current criterion, and the first current criterion are all satisfied, and the first voltage criterion, the second voltage criterion, and the first voltage criterion are all satisfied, the rotation direction of the pumped-storage unit is corrected: if the current rotation direction is the pumping direction, it is changed to the power generation direction; if the current rotation direction is the power generation direction, it is changed to the pumping direction. Among them, the first current criterion is that the positive sequence component and the zero sequence component of the pumped-storage unit terminal current are both less than the third preset current; the second current criterion is that the negative sequence component of the pumped-storage unit terminal current is greater than the fourth preset current; the third current criterion is that the difference between the maximum and minimum values ​​of the three-phase current at the pumped-storage unit terminal is less than the fifth preset current; the first voltage criterion is that the positive sequence component and the zero sequence component of the pumped-storage unit terminal voltage are both less than the fifth preset voltage; the second voltage criterion is that the negative sequence component of the pumped-storage unit terminal voltage is greater than the sixth preset voltage; and the third voltage criterion is that the difference between the maximum and minimum values ​​of the three-phase voltage at the pumped-storage unit terminal is less than the seventh preset voltage.

7. A system for determining the rotation direction of a pumped-storage unit, characterized in that, Includes a rotation direction determination module, used for: If, during the initial rotation direction determination, the pumped-storage unit's grid-connected switch is not closed and either the first or second condition is not met, the pumped-storage unit's rotation direction is determined based on the pumped-storage unit's phase-changing switch status at the moment the rotation direction determination command is received. The first condition is that the instantaneous voltage value of any phase at the pumped-storage unit's terminals is greater than a first preset voltage; the second condition is... The voltage is less than the second preset voltage for a continuous time T. for and Maximum value For phase A voltage and The voltage difference of phase B before time, For phase A voltage and The difference in C-phase voltage before the time, T is the average of all time differences, and the time difference is the time difference between the nearest three-phase voltage zero crossings in the same direction before the first condition is met; the moment of the first determination of the rotation direction is located within the time period between two adjacent shutdowns of the pumped-storage unit. If the rotation direction determination is performed for the first time, the pumped-storage unit grid connection switch is not closed, and both the first and second conditions are met; or if the rotation direction determination is not performed for the first time, the first criterion is not met, and the second criterion is not met, based on the current time... The pumped-storage unit's rotation direction is determined by monitoring the commutation switch status. The first criterion is that conditions three, four, and five are all met. The second criterion is that the pumped-storage unit's grid-connected switch is closed and the relay protection is activated. The third condition is that both the negative-sequence current and zero-sequence current at the pumped-storage unit's terminals are less than a first preset current. The fourth condition is that both the negative-sequence voltage and zero-sequence voltage at the pumped-storage unit's terminals are less than a fourth preset voltage. The fifth condition is... The duration of the current exceeding the second preset current is greater than the first preset time. This represents the maximum single-phase current within the previous cycle at the current moment; If the rotation direction determination is not performed for the first time and the first criterion or the second criterion is satisfied, the result of the most recent pumped-storage unit rotation direction determination remains unchanged.

8. A computer-readable storage medium storing computer instructions thereon, characterized in that, When the computer instruction is executed by the processor, it implements the steps of the method for determining the rotation direction of the pumped storage unit as described in any one of claims 1-6.

9. A computer device, characterized in that, include: Memory, used to store computer instructions; A processor is configured to execute the computer instructions to implement the steps of the pumped storage unit rotation direction determination method according to any one of claims 1-6.

10. A computer program product comprising computer instructions, characterized in that, When executed by the processor, the computer instructions implement the steps of the method for determining the rotation direction of the pumped storage unit as described in any one of claims 1-6.

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