Pumped storage unit splitting failure protection method and related device

Abstract

The invention discloses a pump storage group splitting failure protection method and a related device. The method comprises the following steps: acquiring the three-phase total active power P of a generator, the real-time rotating speed n of a generator set and HWJ and TWJ auxiliary contact signals of a GCB; according to the three-phase total active power P of the generator, the real-time rotating speed n of the generator set and HWJ and TWJ auxiliary contact signals of the GCB, judging whether the GCB is in a pseudo splitting state or not; when the GCB is in the pseudo splitting state, the generator reverse power protection criterion and the generator GCB failure protection criterion are optimized, splitting failure protection of the pumped storage unit is completed, the method and the related device can achieve the pseudo splitting backup protection function of the GCB, the operation safety of the unit is improved, and equipment damage is prevented.

Description

Technical Field

[0001] This invention belongs to the field of power system relay protection and relates to a method and related device for protecting pumped storage units from disconnection failure. Background Technology

[0002] Pumped storage units play multiple critical roles in modern power systems, including peak shaving, valley filling, frequency regulation, phase regulation, and emergency backup. Their operational reliability is crucial for the safety and stability of the power grid. Full-power variable-speed pumped storage units are increasingly widely used due to their superior regulation performance. These units typically require frequent start-ups, shutdowns, and operating condition transitions based on grid dispatch instructions. During this process, the generator output circuit breaker (GCB), as the core switching equipment for electrical connection or isolation between the unit and the grid, directly affects the safe completion of the unit's state transitions.

[0003] Currently, monitoring and protection during the grid connection and disconnection processes of generating units generally rely on auxiliary contact (position switch) signals provided by the GCB (Generator Block) mechanism. Control systems and protection devices determine the grid connection status of the generating unit by receiving these "open" or "close" position signals, and accordingly control the start and stop of equipment such as the excitation system. This design is effective when the GCB's mechanical transmission mechanism is functioning normally. However, as a complex mechanical and electrical device, the GCB's mechanical components, such as transmission links, may break or jam due to material fatigue, assembly defects, or long-term frequent operation. This could lead to a discrepancy between the actual position of its main contacts (primary circuit) and the feedback signal from the auxiliary contacts (secondary circuit).

[0004] When the generator unit performs a disconnection operation, if a GCB mechanical linkage fault occurs, an abnormal situation may arise where the auxiliary contacts have switched to the "open" position while the main contacts remain closed. Upon receiving the open signal, the control system will de-excite the generator unit according to the normal procedure. At this time, since the generator main circuit is still actually connected to the energized grid, the de-excited unit will enter a de-excited asynchronous operation state, absorbing a large amount of reactive power from the grid. This is commonly referred to as "abnormal motor mode." This operating condition may cause overcurrent in the generator stator windings and overheating of the rotor surface. If it is not detected and cleared in time, there is a potential risk of serious electrical damage or secondary accidents to the unit.

[0005] Existing generator protection systems, such as loss-of-excitation protection, reverse power protection, and low-impedance protection, typically base their operation criteria on the amplitude, phase, or rate of change of electrical quantities. In the initial stages of the aforementioned special fault, the changes in electrical quantities may not have reached the setting threshold of traditional protection systems, or their change characteristics may not perfectly match the fault modes preset by traditional protection systems. This could lead to a delay in protection operation, or even failure to operate. Therefore, relying solely on traditional backup protection may not be sufficient to effectively identify this specific "pseudo-tripping" state caused by a mechanical fault in primary equipment in the first instance.

[0006] Therefore, in the context of frequent start-ups and shutdowns of pumped storage, especially full-power variable speed units, a unique, fast, and reliable special discrimination method is designed to address the special hidden danger of "inconsistency between position signal and actual state of primary circuit" caused by GCB mechanical failure. This method constitutes a beneficial supplement to the existing protection system and has important engineering practical value for improving unit operation safety and preventing major equipment damage. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and related device for protecting pumped storage units from disconnection failure. This method and related device can realize the backup protection function of GCB pseudo disconnection, improve the safety of unit operation, and prevent equipment damage.

[0008] To achieve the above objectives, this invention discloses a method for protecting pumped storage units from disconnection failure, comprising: Acquire the three-phase total active power P of the generator, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB; The three-phase total active power P of the generator, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB are used to determine whether the GCB is in a pseudo-disconnection state. When the GCB is in a pseudo-disconnection state, the generator reverse power protection criterion and the generator GCB failure protection criterion are optimized to complete the disconnection failure protection of the pumped storage unit.

[0009] Furthermore, the process of obtaining the total three-phase active power P of the generator is as follows: The instantaneous values ​​of the three-phase voltage and current at the generator terminals are collected. The fundamental effective values ​​and phases of each phase voltage and current are calculated using a real-time digital signal processing algorithm. The total three-phase active power P of the generator is calculated based on the fundamental effective values ​​and phases of each phase voltage and current.

[0010] Furthermore, the process of determining whether the GCB is in a pseudo-disconnection state based on the three-phase total active power P of the generator, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB is as follows: The start-up time T0 is determined based on the HWJ and TWJ auxiliary contact signals of GCB, and a discrimination time window [T0, T0+Δt] is constructed. Within the discrimination time window [T0, T0+Δt], it is determined whether the GCB is in a pseudo-disconnection state based on the total three-phase active power P of the generator and the real-time speed n of the generator set.

[0011] Furthermore, the process of determining whether GCB is in a pseudo-disconnection state based on the total three-phase active power P of the generator and the real-time speed n of the generator set within the discrimination time window [T0, T0+Δt] is as follows: Within the discrimination time window [T0, T0+Δt], if |P| is greater than P_min for more than a short delay t1, then criterion 1 is established, where P_min is the minimum threshold for stable operation of the generator in grid-connected state; Within the discrimination time window [T0, T0+Δt], if the real-time speed n of the generator set is always greater than or equal to 95% ns and the rate of change dn / dt of the real-time speed n of the generator set is always greater than the negative threshold, then the judgment criterion 2 is established, where ns is the grid synchronous speed. When both criteria 1 and criterion 2 are true, GCB is considered to be in a pseudo-unblocking state.

[0012] Furthermore, the process of optimizing the generator reverse power protection criterion is as follows: Cancel the GCB location node latch; The reverse power protection is triggered and an alarm signal is issued. A trip command is sent to the GCB, and a start signal is sent to the GCB failure protection.

[0013] Furthermore, the process of optimizing the generator GCB failure protection criterion is as follows: Set the sensitive segment current setting value I_set.sen; After the GCB failure protection is activated, after a short delay t2, it checks whether the generator terminal current is greater than the sensitive section current setting value I_set.sen. When the generator terminal current is greater than the sensitive section current setting value I_set.sen, the GCB is determined to be malfunctioning, and a command to trip the high-voltage side circuit breaker of the main transformer is issued to achieve the final isolation of the fault.

[0014] This invention discloses a pumped storage unit tripping failure protection system, comprising: The acquisition module is used to acquire the three-phase total active power P of the generator, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB. The judgment module is used to determine whether the GCB is in a pseudo-disconnection state based on the three-phase total active power P of the generator, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB. The optimization module is used to optimize the generator reverse power protection criteria and generator GCB failure protection criteria when the GCB is in a pseudo-disconnection state, so as to complete the disconnection failure protection of the pumped storage unit.

[0015] Furthermore, the determination module includes: The construction unit is used to determine the start time T0 based on the HWJ and TWJ auxiliary contact signals of GCB and construct the discrimination time window [T0, T0+Δt]. The judgment unit is used to determine whether the GCB is in a pseudo-disconnection state based on the total three-phase active power P of the generator and the real-time speed n of the generator set within the judgment time window [T0, T0+Δt].

[0016] The present invention discloses a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the pumped storage unit disconnection failure protection method.

[0017] The present invention discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the pumped storage unit disconnection failure protection method.

[0018] The present invention has the following beneficial effects: In specific operation, the pumped storage unit disconnection failure protection method and related device described in this invention integrates multi-dimensional criteria such as power and speed to construct an independent and effective "pseudo-disconnection" status identification method. This method can identify special risks caused by GCB mechanical failures earlier and more accurately, improve the overall safety protection level of pumped storage units under frequent start-stop conditions, and provide a valuable supplement to the existing protection system. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram illustrating an exemplary embodiment of the present invention; Figure 2This is a schematic diagram showing the installation position of the generator terminal circuit breaker GCB in this invention; Figure 3 This is a schematic diagram of the method flow in this invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0023] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0024] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0025] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0026] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0028] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0029] Example 1 The pumped storage unit disconnection failure protection method described in this invention aims to solve the unit safety risks that may be caused by the primary circuit not actually disconnecting (i.e., "pseudo-disconnection") due to a mechanical linkage fault in the generator outlet circuit breaker (GCB). The following is in conjunction with the appendix... Figure 1 , Figure 2 , Figure 3 The present invention will be described in detail below with reference to specific embodiments.

[0030] Specifically, the following steps are included: 1) Data collection and triggering; The data acquisition and triggering system synchronously acquires the instantaneous values ​​of the three-phase voltage and current at the generator terminals at a sampling rate of no less than 1200 times per second. Then, through a real-time digital signal processing algorithm (using a half-wave algorithm), it calculates the fundamental effective value and phase of each phase voltage and current, and subsequently calculates the total three-phase active power P of the generator online. P = U a I a cosθ a + U b I b cosθ b + U c I c cosθ c Where, θ a θ b and θ c These represent the phase difference between the voltage and current of each phase.

[0031] Meanwhile, the system acquires the real-time speed n of the generator set at a rate of no less than 100 times per second, and performs continuous scanning and anti-jitter processing on the HWJ and TWJ auxiliary contact signals of the GCB (using a 15ms acknowledgment delay) to obtain a stable and reliable circuit breaker position status logic quantity.

[0032] 2) The state change detection and judgment time window is activated; The core processing unit continuously monitors the logic states of HWJ and TWJ. When it detects that HWJ changes from logic "1" (representing closing) to "0" and TWJ changes from logic "0" to "1" (representing opening), it determines that a GCB opening operation has been executed, and records the moment when both position signals are confirmed to be stable as the start time T0.

[0033] At time T0, a preset time window for discrimination [T0, T0+Δt] is immediately initiated. The preset time window Δt is a key parameter, and its setting needs to take into account the following factors: The inherent full opening time (t_GCB) of the GCB body from receiving the opening command to the main contacts completely separating and extinguishing the arc is usually 60ms ~ 120ms. After opening, the time required for the transient process of electrical quantities (voltage, current) at the machine terminal to decay provides sufficient observation time for speed criterion.

[0034] In summary, Δt can be tuned within the range of 0.0 seconds to 3.0 seconds. This time window is used to accommodate the parallel computation and comprehensive judgment of subsequent criteria.

[0035] 3) Multi-criteria fusion identification of "pseudo-solution" states. Within the discrimination time window [T0, T0+Δt], the system performs parallel calculations and judgments of the following two core criteria, and finally makes a fusion decision: Criterion 1 (Minimum Generator Power Criterion): The system continuously calculates and monitors the absolute value of the generator's active power P, |P|. A "minimum threshold for stable operation of the generator in grid-connected state" P_min is set. The setting principle for P_min is: higher than the maximum residual power that the unit may have after a successful GCB trip. This residual power mainly originates from the small amount of active power corresponding to the unit's rotating mechanical losses, and is based on the minimum stable control power value provided by the generator manufacturer. Typically, P_min can be taken as 0.5% to 2% of the unit's rated active power.

[0036] Within the time window, if |P| is greater than P_min for a period of time exceeding a short delay t1 (50ms, used to avoid transient fluctuations), then criterion 1 is satisfied, indicating that the generator still has significant power exchange and has not entered the expected no-load or shutdown state.

[0037] Criterion 2 (Generator Speed ​​Criterion under Shutdown and De-connection Status): The system analyzes the change behavior of speed n within a time window. For pumped storage units, if de-connection is successful, its speed will begin to decrease under the control of the turbine speed regulation system. This criterion is set as follows: Speed ​​maintenance check: Within the time window [T0, T0+Δt], calculate the relative percentage of speed n to the grid synchronous speed ns_. If, throughout the entire time window, condition 1: if speed n is consistently not lower than 95% ns, then the speed is considered not to have exhibited the expected downward trend after decoupling; condition 2: check whether the speed change rate dn / dt is consistently greater than a negative threshold (-0.1% ns) to confirm that the speed has not begun to decrease effectively.

[0038] If conditions 1 and 2 are met, then criterion 2 is satisfied, indicating that the generator rotor is still strongly coupled with the power grid and has not broken free from the synchronization constraint.

[0039] Comprehensive judgment: Within the judgment time window [T0, T0+Δt], if criterion 1 and criterion 2 are satisfied simultaneously in time (i.e., the time periods of satisfying the conditions overlap, or both are satisfied until the end of the window), then the comprehensive judgment is "inconsistent state", that is, GCB is in "pseudo-de-segmentation" state, and outputs a high-level "pseudo-de-segmentation" action flag.

[0040] 4) Optimize protection logic linkage and backup trip execution This invention achieves ultimate security protection by optimizing the logic configuration of existing protection devices, specifically as follows: The optimized generator reverse power protection criterion is as follows: Key optimization point: Remove GCB location node locking.

[0041] In traditional generator reverse power protection logic, the "open position" signal (TWJ) of the GCB is typically used as the blocking condition. That is, when TWJ=1, the unit is considered to have been disconnected, and reverse power protection is automatically blocked to prevent false tripping. This invention eliminates this blocking logic. After optimization, reverse power protection remains open for monitoring regardless of the TWJ signal status.

[0042] Action logic: When the reverse power protection detects that the active power absorbed by the generator exceeds its set value (-Pset), it will take action immediately after the original delay.

[0043] In the "pseudo-disconnection" scenario, since the GCB is not actually disconnected and the excitation has been stopped, the unit will operate asynchronously to absorb active power, thereby reliably triggering the reverse power protection. After the reverse power protection is activated, in addition to issuing the original alarm signal, it will send a trip command to the GCB again, and at the same time send a start signal to the GCB failure protection.

[0044] The optimized generator GCB failure protection criterion is as follows: Optimized start-up conditions: Based on the traditional GCB failure protection (started after other protection trips the GCB, and failure occurs if the current persists after a delay), an independent start-up channel is added. The start-up conditions for this channel are: "GCB's TWJ trip signal is valid" (indicating a trip command) and "F_weijieli output by the core processing unit = 1" (indicating that the system has been determined to be in a "pseudo-disconnection" state) must be met simultaneously.

[0045] Add a sensitive overcurrent criterion: To ensure reliable operation even when the current is small due to low power absorption in a "pseudo-disconnection" state, a sensitive segment is added to the current criterion of the failure protection. This sensitive segment has a low current setting value I_set.sen, which can reliably respond to the current generated by the minimum power corresponding to P_min in "Criterion 1". For example, I_set.sen can be calculated as P_min / (rated voltage) with a certain reliability factor considered.

[0046] Action Logic: After the GCB failure protection is activated (whether through the traditional channel or the "pseudo-tripping" channel added in this invention), after a short delay t2 (usually 150ms ~ 250ms, used to avoid the possible operation time of the GCB itself and its re-tripping), it checks whether the generator terminal current is still greater than the aforementioned sensitive section current setting I_set.sen. If the current persists, it is determined that the GCB has failed, and an instruction to trip the high-voltage side circuit breaker of the main transformer (or all adjacent circuit breakers) is immediately issued to achieve final isolation of the fault.

[0047] In this embodiment, the threshold values ​​for P_min and 95% of the rotational speed can be fine-tuned based on experimental data of the actual characteristics of the unit. The length of the discrimination time window Δt can be optimized based on the unit's inertial time constant and the response characteristics of the control system.

[0048] In this embodiment, the "sensitive segment overcurrent criterion" can also use negative sequence current, zero sequence current or other characteristic quantities as auxiliary or alternative criteria to enhance reliability.

[0049] This invention can also be applied to the verification of the grid connection process of generating units. The principle is similar, but the criteria are reversed to prevent "pseudo-grid connection".

[0050] Through the above specific implementation methods, the present invention can effectively address the special and dangerous hidden fault of "pseudo-disconnection" caused by GCB mechanical failure, and provides a new and effective means to ensure the safe and stable operation of pumped storage units.

[0051] Example 2 The pumped storage unit disconnection failure protection system of the present invention includes: The acquisition module is used to acquire the three-phase total active power P of the generator, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB. The judgment module is used to determine whether the GCB is in a pseudo-disconnection state based on the three-phase total active power P of the generator, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB. The optimization module is used to optimize the generator reverse power protection criteria and generator GCB failure protection criteria when the GCB is in a pseudo-disconnection state, so as to complete the disconnection failure protection of the pumped storage unit.

[0052] Furthermore, the determination module includes: The construction unit is used to determine the start time T0 based on the HWJ and TWJ auxiliary contact signals of GCB and construct the discrimination time window [T0, T0+Δt]. The judgment unit is used to determine whether the GCB is in a pseudo-disconnection state based on the total three-phase active power P of the generator and the real-time speed n of the generator set within the judgment time window [T0, T0+Δt].

[0053] The module division in this embodiment is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in each embodiment of this application can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0054] Example 3 A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of a pumped-storage unit disconnection failure protection method. For example, the method includes: acquiring the three-phase total active power P of the generator, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB; determining whether the GCB is in a pseudo-disconnection state based on the three-phase total active power P of the generator, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB; and optimizing the generator reverse power protection criterion and the generator GCB failure protection criterion when the GCB is in a pseudo-disconnection state to complete the disconnection failure protection of the pumped-storage unit. The memory may include main memory, such as high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device. The processor, network interface, and memory are interconnected via an internal bus, which can be an industry standard architecture bus, a peripheral component interconnection standard bus, an extended industry standard architecture bus, etc. The bus can be divided into address bus, data bus, control bus, etc. The memory is used to store programs; specifically, the program may include program code, which includes computer operation instructions. The memory may include main memory and non-volatile memory, and provides instructions and data to the processor.

[0055] Example 4 A computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of a pumped-storage unit disconnection failure protection method. For example, the method includes: acquiring the three-phase total active power P of the generator, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB; determining whether the GCB is in a pseudo-disconnection state based on the three-phase total active power P, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB; and optimizing the generator reverse power protection criterion and the generator GCB failure protection criterion when the GCB is in a pseudo-disconnection state to complete the disconnection failure protection of the pumped-storage unit. Specifically, the computer-readable storage medium includes, but is not limited to, volatile memory and / or non-volatile memory. The volatile memory may include random access memory (RAM) and / or cache memory, etc. The non-volatile memory may include read-only memory (ROM), hard disk, flash memory, optical disk, magnetic disk, etc.

[0056] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application 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.

[0057] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. 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... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0058] 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.

[0059] 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.

[0060] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0061] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0062] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for protecting pumped storage units from disconnection failure, characterized in that, include: Acquire the three-phase total active power P of the generator, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB; The three-phase total active power P of the generator, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB are used to determine whether the GCB is in a pseudo-disconnection state. When the GCB is in a pseudo-disconnection state, the generator reverse power protection criterion and the generator GCB failure protection criterion are optimized to complete the disconnection failure protection of the pumped storage unit.

2. The pumped storage unit disconnection failure protection method according to claim 1, characterized in that, The process of obtaining the total three-phase active power P of the generator is as follows: The instantaneous values ​​of the three-phase voltage and current at the generator terminals are collected. The fundamental effective values ​​and phases of each phase voltage and current are calculated using a real-time digital signal processing algorithm. The total three-phase active power P of the generator is calculated based on the fundamental effective values ​​and phases of each phase voltage and current.

3. The pumped storage unit disconnection failure protection method according to claim 1, characterized in that, The process of determining whether the GCB is in a pseudo-disconnection state based on the three-phase total active power P of the generator, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB is as follows: The start-up time T0 is determined based on the HWJ and TWJ auxiliary contact signals of GCB, and a discrimination time window [T0, T0+Δt] is constructed. Within the discrimination time window [T0, T0+Δt], it is determined whether the GCB is in a pseudo-disconnection state based on the total three-phase active power P of the generator and the real-time speed n of the generator set.

4. The pumped storage unit disconnection failure protection method according to claim 3, characterized in that, The process of determining whether GCB is in a pseudo-disconnection state based on the total three-phase active power P of the generator and the real-time speed n of the generator set within the discrimination time window [T0, T0+Δt] is as follows: Within the discrimination time window [T0, T0+Δt], if |P| is greater than P_min for more than a short delay t1, then criterion 1 is established, where P_min is the minimum threshold for stable operation of the generator in grid-connected state; Within the discrimination time window [T0, T0+Δt], if the real-time speed n of the generator set is always greater than or equal to 95% ns and the rate of change dn / dt of the real-time speed n of the generator set is always greater than the negative threshold, then the judgment criterion 2 is established, where ns is the grid synchronous speed. When both criteria 1 and criterion 2 are true, GCB is considered to be in a pseudo-unblocking state.

5. The pumped storage unit disconnection failure protection method according to claim 1, characterized in that, The process of optimizing the generator reverse power protection criterion is as follows: Cancel the GCB location node latch; The reverse power protection is triggered and an alarm signal is issued. A trip command is sent to the GCB, and a start signal is sent to the GCB failure protection.

6. The pumped storage unit disconnection failure protection method according to claim 3, characterized in that, The process of optimizing the generator GCB failure protection criterion is as follows: Set the sensitive segment current setting value I_set.sen; After the GCB failure protection is activated, after a short delay t2, it checks whether the generator terminal current is greater than the sensitive section current setting value I_set.sen. When the generator terminal current is greater than the sensitive section current setting value I_set.sen, the GCB is determined to be malfunctioning, and a command to trip the high-voltage side circuit breaker of the main transformer is issued to achieve the final isolation of the fault.

7. A pumped storage unit disconnection failure protection system, characterized in that, include: The acquisition module is used to acquire the three-phase total active power P of the generator, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB. The judgment module is used to determine whether the GCB is in a pseudo-disconnection state based on the three-phase total active power P of the generator, the real-time speed n of the generator set, and the HWJ and TWJ auxiliary contact signals of the GCB. The optimization module is used to optimize the generator reverse power protection criteria and generator GCB failure protection criteria when the GCB is in a pseudo-disconnection state, so as to complete the disconnection failure protection of the pumped storage unit.

8. The pumped storage unit disconnection failure protection system according to claim 7, characterized in that, The judgment module includes: The construction unit is used to determine the start time T0 based on the HWJ and TWJ auxiliary contact signals of GCB and construct the discrimination time window [T0, T0+Δt]. The judgment unit is used to determine whether the GCB is in a pseudo-disconnection state based on the total three-phase active power P of the generator and the real-time speed n of the generator set within the judgment time window [T0, T0+Δt].

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the pumped storage unit disconnection failure protection method as described in any one of claims 1-6.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the pumped storage unit disconnection failure protection method as described in any one of claims 1-6.

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