Zero-power protection method and device for thermal power generating unit and computer readable storage medium

Abstract

The invention relates to a zero-power protection method and device for a thermal power generating unit and a computer readable storage medium, and the method comprises the steps: obtaining an electromechanical imbalance coefficient and an electrical parameter of the thermal power generating unit and the rotating speed of a steam turbine in response to a starting request of a zero-power protection system; if the electromechanical unbalance coefficient is within a preset threshold range and the rotating speed of the steam turbine is greater than or equal to a preset rotating speed threshold, the power requirement for protecting the thermal power generating unit is met; if the electrical parameters meet the electrical conditions, the electrical requirements for protecting the thermal power generating unit are met; and when the power requirement and the electrical requirement are met at the same time, a zero-power protection measure is executed. According to the invention, the accuracy of the zero-power protection device of the thermal power generating unit is improved.

Description

Technical Field

[0001] The present application relates to the field of power system protection, and in particular to a method, device and computer-readable storage medium for zero-power protection of thermal power units. Background Art

[0002] Zero-power protection devices are used to prevent overspeed and other potential hazards in steam turbine generator sets when they lose load or experience abnormal operating conditions, thereby ensuring the safe operation of power plant equipment. These devices primarily detect the operating and shutdown status of the main transformer and disconnect the generator and turbine in the event of a zero-power fault, thereby reducing the risk of equipment damage.

[0003] Existing zero-power protection devices typically rely on changes in electrical quantities as a basis for judgment. In complex power grids, these devices often ignore turbine operating conditions, making them prone to false tripping. Therefore, improving the accuracy of zero-power protection devices for thermal power plants has become an urgent issue. Summary of the Invention

[0004] The embodiments of the present application provide a method, device and computer-readable storage medium for zero-power protection of a thermal power plant to at least solve the problem of low reliability and accuracy of zero-power protection devices for thermal power plants in related technologies.

[0005] In a first aspect, an embodiment of the present application provides a zero-power protection method for a thermal power unit, the method being applied to a zero-power protection system, the method comprising:

[0006] In response to a start-up request of the zero power protection system, obtaining an electromechanical unbalance coefficient, electrical parameters, and a rotational speed of a steam turbine of the thermal power unit;

[0007] If the electromechanical unbalance coefficient is within a preset threshold range and the turbine speed is greater than or equal to the preset speed threshold, the power requirement for protecting the thermal power unit is met; if the electrical parameters meet the electrical conditions, the electrical requirements for protecting the thermal power unit are met;

[0008] When the power requirement and the electrical requirement are simultaneously met, a zero-power protection measure is performed.

[0009] In one embodiment, the electrical parameters include the power of the thermal power unit, the current of any two phases of the thermal power unit, the effective value of the current, and the delay time of the thermal power unit fault judgment. The electrical parameters satisfying the electrical conditions include:

[0010] During a first preset time period, the power of the thermal power generation unit is greater than or equal to a first preset power threshold;

[0011] The current of any two phases of the thermal power generation unit is less than a preset first current threshold;

[0012] Within a second preset time period, the change in the effective value of the current is greater than or equal to a preset second current threshold;

[0013] The thermal power unit fault judgment delay time is greater than or equal to a preset time threshold;

[0014] When the thermal power generation unit fails, the power of the thermal power generation unit is less than a second preset power threshold.

[0015] In one embodiment, executing the zero power protection measure includes:

[0016] Stop the steam turbine operation;

[0017] Turn off the generator output switch and demagnetization switch;

[0018] Start the steam turbine emergency trip system and boiler interlock system.

[0019] In one embodiment, the thermal power unit includes a steam turbine and has a rapid load reduction function, and the zero power protection measure further includes:

[0020] Close the high-pressure regulating valve and the medium-pressure regulating valve of the steam turbine.

[0021] In one embodiment, before responding to the startup request of the zero power protection system, the method further includes:

[0022] Obtain the active power and operating current of the thermal power unit;

[0023] If the active power is greater than a preset state power threshold, determining that the operating state of the thermal power unit is an operation state;

[0024] If the active power is less than the preset state power threshold and the operating current is less than the preset state current threshold, determining that the operating state of the thermal power unit is a shutdown state;

[0025] If the active power is less than the preset state power threshold, and the operating current is greater than the preset state current threshold, it is determined that the operating state of the thermal power unit is abnormal, and an abnormality alarm is sent.

[0026] In one embodiment, the thermal power generation unit includes a transformer, and the method further includes:

[0027] Receive the voltage and current on the high-voltage side of the transformer;

[0028] If only the current is received, the abnormal current loop is blocked and a current disconnection alarm is sent;

[0029] When only the voltage is received, the abnormal voltage circuit is blocked and a voltage disconnection alarm is sent.

[0030] In one embodiment, responding to the startup request of the zero power protection system includes:

[0031] In response to a power mutation amount of the thermal power unit being greater than or equal to a preset power threshold, triggering the start request; and / or

[0032] In response to the current mutation being greater than or equal to a preset current threshold, the start request is triggered.

[0033] In a second aspect, an embodiment of the present application provides a zero-power protection device for a thermal power unit, characterized in that the device is applied to a zero-power protection system, and the device includes:

[0034] an obtaining module, configured to obtain, in response to a start-up request of the zero power protection system, an electromechanical unbalance coefficient, electrical parameters, and a rotational speed of the steam turbine of the thermal power unit;

[0035] a protection requirement satisfaction module, configured to satisfy the power requirement for protecting the thermal power unit if the electromechanical unbalance coefficient is within a preset threshold range and the turbine speed is greater than or equal to a preset speed threshold; and satisfy the electrical requirement for protecting the thermal power unit if the electrical parameters satisfy the electrical conditions;

[0036] An execution module executes a zero-power protection measure when the power requirement and the electrical requirement are met simultaneously.

[0037] In a third aspect, an embodiment of the present application provides a computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the zero-power protection method for a thermal power unit as described in the first aspect above is implemented.

[0038] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the zero-power protection method for a thermal power unit as described in the first aspect above.

[0039] The zero-power protection method, device, and computer-readable storage medium for thermal power units provided in the embodiments of the present application have at least the following technical effects.

[0040] The zero power protection system is started by determining the mutation amount of the thermal power unit, and the zero power protection measures are executed when the judgment conditions on the power side and the judgment conditions on the electrical side are met at the same time. When the thermal power unit is protected from zero power, the power and speed of the turbine are fully considered, and the judgment conditions on the electrical side are combined, thereby improving the accuracy of the zero power protection of the thermal power unit.

[0041] The details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0043] Figure 1 is a flow chart showing a zero-power protection method for a thermal power unit according to an exemplary embodiment;

[0044] Figure 2 is a schematic diagram showing that electrical parameters meet protection conditions according to an exemplary embodiment;

[0045] Figure 3 is a schematic diagram illustrating an exemplary operation principle of a slightly unbalanced power load;

[0046] Figure 4 is a schematic diagram showing a start request and automatic locking according to an exemplary embodiment;

[0047] Figure 5 is a block diagram of a zero-power protection device for a thermal power plant according to an exemplary embodiment;

[0048] Figure 6 is a block diagram of an electronic device according to an exemplary embodiment. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is described and illustrated below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely used to explain this application and are not intended to limit this application. Based on the embodiments provided in this application, all other embodiments obtained by those of ordinary skill in the art without making any creative efforts are within the scope of protection of this application.

[0050] Obviously, the drawings described below are merely examples or embodiments of the present application. Those skilled in the art can, without inventive effort, apply the present application to other similar scenarios based on these drawings. Furthermore, it is also understood that, although the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, changes in design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as an insufficiency of the content disclosed in this application.

[0051] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments unless there is a conflict.

[0052] Unless otherwise defined, the technical or scientific terms used in this application should have the ordinary meaning understood by a person of ordinary skill in the technical field to which this application belongs. The words "one", "a", "the" and the like used in this application do not indicate a limit on quantity and may indicate the singular or plural. The terms "include", "comprise", "have" and any variations thereof used in this application are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units that are inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The word "multiple" used in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific order for the objects.

[0053] In a first aspect, the present invention provides a method for zero power protection of a thermal power plant. Figure 1 The flowchart of a zero-power protection method for a thermal power unit according to an exemplary embodiment includes:

[0054] Step S101: In response to a start-up request of a zero power protection system, an electromechanical unbalance coefficient, electrical parameters and a rotation speed of a steam turbine of a thermal power unit are obtained.

[0055] Get the parameters of the thermal power unit zero power protection system startup request: the power mutation amount and current mutation amount of the thermal power unit. When the power mutation amount and current mutation amount meet any of the following startup requests, the zero power protection system startup is triggered:

[0056] In response to a sudden power change of the thermal power unit being greater than or equal to a preset power threshold, a startup request is triggered. In response to a sudden current change of the thermal power unit being greater than or equal to a preset current threshold, a startup request is triggered.

[0057] In other words, when any one of the power mutation and current mutation of the thermal power unit meets the above conditions, the zero power protection system is triggered and started.

[0058] Optionally, the preset power threshold is 30% of the rated power of the thermal power unit, and the preset current threshold is 30% of the rated current of the thermal power unit. Specific values of the preset power threshold and the preset current threshold are not specifically limited and are determined based on the thermal power unit in the actual application scenario.

[0059] In one embodiment, in a 500KV booster station with a 600MW thermal power unit, a sudden current change of 250A or greater triggers the activation of the zero-power protection system. In a 600MW thermal power unit, a sudden power change of 200MW or greater triggers the activation of the zero-power protection system.

[0060] When the zero-power protection system activates, the unit's electromechanical imbalance coefficient, electrical parameters, and turbine speed are obtained. The unit's electromechanical imbalance coefficient is indirectly derived from the power of the turbine and generator. Turbine power is represented by the steam pressure at the first stage inlet of the intermediate pressure cylinder (IPC), also known as the intermediate pressure cylinder inlet steam pressure.

[0061] In an optional manner, obtaining the steam turbine power and the generator power comprises the following steps:

[0062] To obtain the power of the steam turbine, the protection card on the steam turbine receives an input signal (for example, the input signal is a current of 4 to 20 mA), samples the measuring point of the intermediate pressure cylinder steam inlet pressure, and obtains the intermediate pressure cylinder steam inlet pressure based on the sampling result, that is, the power of the steam turbine is obtained.

[0063] To obtain the power of the generator, current transformers and voltage transformers are used to obtain the voltage and three-phase current of the generator, and the power of the generator is obtained after calculation by three power transmitters.

[0064] Based on the obtained turbine and generator power, the operating power of the turbine and generator is converted to relative values relative to a baseline value, also known as the per-unit value. The difference between the per-unit value of the turbine power and the per-unit value of the generator power is used as the electromechanical imbalance coefficient, also known as the power-load imbalance coefficient. In other words, the ratio of the intermediate pressure cylinder inlet steam pressure to the rated pressure is used as the first per-unit value, and the ratio of the actual generator load to the rated load is used as the second per-unit value. The electromechanical imbalance coefficient is the difference between the first and second per-unit values.

[0065] The speed of the thermal power unit is obtained through the speed measurement card of the thermal power unit. The electrical parameters of the thermal power unit include the power of the thermal power unit, the current of any two phases of the thermal power unit, the effective value of the current, and the delay time of the thermal power unit fault judgment.

[0066] The electromechanical unbalance coefficient, electrical parameters and turbine speed of the thermal power unit provide execution protection content for the zero power protection system so that the zero power protection system can protect the thermal power unit.

[0067] Step S102: If the electromechanical unbalance coefficient is within the preset threshold range and the turbine speed is greater than or equal to the preset speed threshold, the power requirement for protecting the thermal power unit is met; if the electrical parameters meet the electrical conditions, the electrical requirements for protecting the thermal power unit are met.

[0068] When the electromechanical imbalance coefficient of a thermal power unit is within a preset threshold range, it indicates a slight power load imbalance. This threshold range is determined based on the type and performance of the thermal power unit in use and is not specifically limited. Optionally, because protection based on electrical parameters operates more quickly than the electromechanical imbalance coefficient, its preset threshold range is lower than that of traditional power load imbalance, and can be between 0.15 and 0.3.

[0069] The preset speed threshold is 101% of the rated speed of the steam turbine, and the specific value is determined according to the rated speed of the steam turbine. Optionally, the speed threshold can be selected in the range of 3020r / min to 3040r / min, and preferably, the speed threshold is 3030r / min.

[0070] When the electromechanical unbalance coefficient of the thermal power unit is within the preset threshold range and the turbine speed is greater than the preset speed threshold, it means that the thermal power unit is in a state of slight power load imbalance and the turbine is in the initial stage of overspeed, which meets the power requirements for protecting the thermal power unit.

[0071] Figure 2 is a schematic diagram showing that electrical parameters meet protection conditions according to an exemplary embodiment, such as Figure 2 As shown, according to the electrical parameters of the thermal power unit obtained, when the electrical parameters simultaneously meet the following electrical conditions (i.e., simultaneously meet Figure 2 When conditions b to f) are met, the electrical requirements for protecting thermal power units are met:

[0072] (1) Within a first preset time period, the power of the thermal power unit is greater than or equal to a first preset power threshold.

[0073] The first preset power threshold is 40% of the rated power of the thermal power unit, wherein the specific value of the first preset power threshold is specifically set according to the rated power of the thermal power unit.

[0074] The first preset duration is the duration of time the thermal power unit was operating before a fault occurred. If the power of the thermal power unit during the first preset duration is greater than or equal to the first preset power threshold, and the power of the thermal power unit shows a decreasing trend during the first preset duration, then the current first electrical condition is met. For example, if the first preset duration is 200ms and the first preset power threshold is 240MW, and the power of the thermal power unit is greater than 240MW and shows a decreasing trend 200ms before a fault occurred, then the current first electrical condition is met.

[0075] (2) The current of any two phases of the thermal power unit is less than the preset first current threshold.

[0076] The preset first current threshold is determined by the rated current of the thermal power unit (for example, the preset first current threshold is 37.5% of the rated current). If the current in the thermal power unit is three-phase current, then if the currents of any two phases are less than the preset first current threshold, then the current second electrical condition is satisfied. For example, if 37.5% of the rated current of the thermal power unit is 300A, then when the currents of any two phases of the thermal power unit are less than 300A, then the current second electrical condition is satisfied.

[0077] (3) Within a second preset time period, the change in the effective value of the current is greater than or equal to a preset second current threshold.

[0078] The preset second current threshold is determined by the rated current of the thermal power unit (for example, the preset second current threshold is 30% of the rated current). Within the second preset time length, the change in the effective value of the current is obtained. If the change in the effective value of the current is greater than or equal to the preset second current threshold, the current third electrical condition is met. For example, if the second preset time length is 20ms and the preset second current threshold is 250A, then if the change in the effective value of the current of the thermal power unit within 20ms is greater than 250A, the current third electrical condition is met.

[0079] (4) The thermal power unit fault judgment delay time is greater than or equal to the preset time threshold.

[0080] There is a delay when determining a thermal power unit fault. This delay is to further confirm that a fault has occurred and prevent misjudgments caused by other factors. The fourth electrical condition is met when the thermal power unit fault determination delay is greater than or equal to a preset time threshold. For example, if the preset time threshold is 20ms, then the fourth electrical condition is met when the thermal power unit fault determination delay is greater than or equal to the preset 20ms.

[0081] (5) When the thermal power unit fails, the power of the thermal power unit is less than the second preset power threshold.

[0082] The second preset power threshold is determined by the rated power of the thermal power unit (for example, the second preset power threshold is 1.67% of the rated power of the thermal power unit). When a thermal power unit fails, the power of the thermal power unit in the failed state is less than or equal to the second preset power threshold, and the fifth electrical condition is satisfied. For example, if the second preset power threshold is 10MW, then the power of the thermal power unit in the failed state is less than or equal to 10MW, and the fifth electrical condition is satisfied.

[0083] When the electrical parameters of the thermal power generation unit simultaneously meet the first to fifth electrical conditions, it indicates that the thermal power generation unit is in a load-lost operation state, which may easily cause damage to the generator.

[0084] In one embodiment, Figure 3 is a schematic diagram of an exemplary operation principle of a slightly unbalanced power load, such as Figure 3 As shown, each unit is equipped with three protection cards, each receiving a steam pressure signal from the first stage inlet of the intermediate pressure cylinder, a generator power signal, and a speed signal. The zero-power protection system acquires three data streams, each of which includes the electromechanical imbalance coefficient and the turbine speed. If any two of the three data streams satisfy the electromechanical imbalance coefficient within a preset threshold range and the turbine speed exceeds the preset speed threshold, the power requirement for protecting the thermal power unit is met. In other words, if any card or signal fails, the zero-power protection system's actions to protect the thermal power unit will not be erroneously triggered in the absence of an actual fault or anomaly. PLU Actions 1 through 3 represent the electromechanical imbalance coefficients of the thermal power unit, but they represent the electromechanical imbalance coefficients of different signal sources on the same unit.

[0085] Figure 4 is a schematic diagram showing a start request and automatic locking according to an exemplary embodiment, as shown in FIG. Figure 4 As shown, when the automatic locking signal (i.e. Figure 4When the "zero power protection blocking element (state monitoring module)" in the thermal power unit is not issued, at this time, in response to the power mutation amount of the thermal power unit being greater than or equal to the preset power threshold value 250A, or in response to the current mutation amount being greater than or equal to the preset current threshold value 200MW, the start request (i.e. Figure 4 "Zero power start criterion module conditions are met" in the

[0086] Figure 4 and Figure 2 The HSDELAY module in is a functional module with a first-order lag at the control end. Its function is to perform a first-order lag operation on the input. The calculation procedure is as follows:

[0087]

[0088] In the above calculation program, TC is the first-order inertia time constant. The value set for TC is greater than or equal to 0. When the first-order inertia time constant is set to 0, a pure hysteresis function is implemented.

[0089] Tao is the hysteresis time constant. Its value is an integer multiple of the task period, and the range of integer multiples is 0 to 300. Setting the system (DCS) page sampling period to 20ms and Tao to 1 achieves a 20ms hysteresis. After one cycle (20ms), parameter OUT begins to change.

[0090] Through the above power requirements and electrical requirements for protecting thermal power units, it can be known that there are problems on the power side and electrical side of the thermal power unit, so that the satisfaction of the requirements on the power side and electrical side is used as the prerequisite for whether to implement zero power protection measures.

[0091] Step S103: When the power requirement and the electrical requirement are simultaneously met, a zero-power protection measure is executed.

[0092] When the thermal power unit meets both power and electrical requirements, the zero power protection system fully considers the working status of the steam turbine, avoiding the problem of protection misoperation, thereby enabling the zero power protection system to execute zero power protection measures. Among them, the zero power protection measures specifically include:

[0093] Stop the steam turbine operation;

[0094] Turn off the generator output switch and demagnetization switch;

[0095] Start the steam turbine emergency trip system and boiler interlock system.

[0096] It's important to note that in a thermal power plant, the steam turbine is a key device that converts steam's thermal energy into mechanical energy. If the steam turbine continues to operate without load, it can cause overspeed and other mechanical damage, necessitating immediate shutdown.

[0097] The generator output switch connects the generator to the grid. If the thermal power unit experiences zero power, the generator output switch is quickly closed to cut off the electrical connection between the generator and the grid. This prevents the generator from absorbing power from the grid, thus preventing damage to the generator and the grid.

[0098] The demagnetization switch is used to cut off the generator's excitation current. Since the excitation current is used to maintain the generator's magnetic field, closing the demagnetization switch can quickly reduce the generator's magnetic field strength, thereby reducing stored energy, achieving a rapid shutdown, and protecting the generator.

[0099] The turbine emergency trip system is used to immediately shut down the steam turbine in a thermal power unit under critical operating conditions. When the zero-power protection system is triggered, it controls the turbine shutdown. The turbine emergency trip system also provides additional safety measures to ensure a safe turbine shutdown.

[0100] The boiler-turbine interlock system provides coordinated protection between the boiler and turbine. When the turbine is shut down in an emergency, the boiler's fuel supply continues, and the boiler continues to produce a large amount of steam. However, this steam cannot be utilized by the turbine, leading to boiler overheating and other dangerous situations. To address this situation, the boiler-turbine interlock system simultaneously initiates boiler protection measures (such as reducing fuel supply and stopping combustion) during the turbine emergency shutdown, thereby ensuring the safety of the entire thermal power unit.

[0101] Through the zero-power protection measure in step S103, the harm caused by zero-power operation is reduced, the safety of the thermal power unit is guaranteed, and the stability of the thermal power unit is improved.

[0102] Through steps S101 to S103, when a thermal power unit meets both its power and electrical requirements, zero-power protection measures are implemented to ensure the unit's safety. The power requirements of the thermal power unit fully account for situations where the turbine's power load is slightly unbalanced and the speed exceeds a threshold, and are combined with the electrical requirements of the electrical side. This improves the accuracy of the zero-power protection system in zero-power situations and avoids the risk of false tripping caused by prior art techniques that rely solely on electrical-side signals.

[0103] Before responding to the startup request of the zero power protection system in step S101, the zero power protection system also monitors the generator and main transformer in the thermal power unit to ensure the safe operation of the thermal power unit, specifically including:

[0104] Obtain the active power and operating current of the thermal power unit;

[0105] If the active power is greater than the preset state power threshold, the operating state of the thermal power unit is determined to be the operation state.

[0106] If the active power is less than the preset state power threshold and the operating current is less than the preset state current threshold, it is determined that the operating state of the thermal power unit is the shutdown state.

[0107] If the active power is less than the preset state power threshold and the operating current is greater than the preset state current threshold, the operating state of the thermal power unit is determined to be abnormal and an abnormal alarm is sent.

[0108] In one embodiment, the preset state power threshold is 240MW, and the preset state current threshold is 300A. If the active power of the thermal power unit is greater than 240MW, the operating state of the thermal power unit is the commissioning state, that is, the thermal power unit is in a normal startup state and there are no abnormal conditions. If the active power of the thermal power unit is less than 240MW and the operating current is less than 300A, the thermal power unit is in a shutdown state, that is, the thermal power unit is in a shutdown state. If the active power of the thermal power unit is less than 240MW and the operating current is greater than 300A, the thermal power unit is in an abnormal state, and an abnormal alarm is sent to remind staff to perform maintenance.

[0109] For the zero power protection system, the input quantity that responds to the startup request of the zero power protection system is the voltage and current on the high voltage side of the transformer. By receiving the voltage and current, it is determined whether the thermal power unit has zero power. The monitoring content specifically includes:

[0110] Receive the voltage and current on the high voltage side of the transformer.

[0111] If only the current is received, the abnormal current loop is blocked and a current disconnection alarm is sent.

[0112] When only the voltage is received, the abnormal voltage circuit is blocked and a voltage disconnection alarm is sent.

[0113] If the zero-power protection system receives only one of the current and voltage on the high-voltage side of the transformer, it automatically blocks the abnormal circuit. If the zero-power protection system does not receive current, it determines within a preset delay that the zero-power protection system has indeed not received current. It then blocks the abnormal current circuit and issues a current disconnection alarm. When the zero-power protection system receives current again, it reopens the current circuit after the preset delay.

[0114] If the zero-power protection system fails to receive voltage, it will determine within a preset delay that the system has indeed failed to receive voltage. It will then close the abnormal voltage circuit and issue a voltage disconnection alarm. When the zero-power protection system receives voltage again, meaning the voltage anomaly disappears, it will reopen the voltage circuit according to the preset delay.

[0115] It should be noted that the purpose of the preset delay time is to further confirm whether the current or voltage is not received, so as to avoid the influence of accidental factors or short-term fluctuations of current and voltage.

[0116] In one embodiment, a preset delay of 5 seconds is used. When the zero-power protection device does not receive current, the current anomaly circuit is automatically closed and a current disconnection alarm is issued after a delay of 5 seconds. When the current anomaly disappears, the current circuit is reopened after a delay of 5 seconds, allowing the zero-power protection system to receive current again.

[0117] In another embodiment, a preset delay of 5 seconds is used. When the zero-power protection device does not receive voltage, the voltage anomaly circuit is automatically closed and a voltage disconnection alarm is issued after a delay of 5 seconds. When the voltage anomaly disappears, the voltage circuit is reopened after a delay of 5 seconds, allowing the zero-power protection system to receive voltage again.

[0118] In another embodiment, after the generator and transformer have performed protection actions, the zero power protection system is automatically locked so that the zero power protection system no longer repeatedly performs zero power protection measures.

[0119] The zero-power protection system in this application also has an adaptive function. When current and voltage reception anomalies occur, it automatically blocks the abnormal circuit and delays the circuit restoration after the fault disappears. Furthermore, after the generator and transformer protection function is activated, the zero-power protection system automatically blocks, avoiding redundant protection and unnecessary consumption.

[0120] The above method is for thermal power plants without FCB (Fast Cutback) functionality. For thermal power plants with FCB functionality, the corresponding power and electrical requirements are different, and the zero-power protection measures are also different. Specifically:

[0121] A thermal power unit equipped with FCB functionality can rapidly reduce the generator's output power upon detecting a fault or anomaly to maintain system stability and safety. Therefore, the electrical parameters of a thermal power unit equipped with FCB functionality can be considered without regard to the electrical parameters on the electrical side. In other words, the electrical parameters of a thermal power unit equipped with FCB functionality are assumed to meet the electrical conditions, i.e., the electrical requirements for protecting the thermal power unit. This allows the zero-power protection system to only consider the power requirements of the thermal power unit. According to step S102, the power requirements of the thermal power unit meet:

[0122] If the electromechanical unbalance coefficient is within the preset threshold range and the turbine speed is greater than or equal to the preset speed threshold, the power requirement for protecting the thermal power unit is met.

[0123] It should be noted that FCB is an automatic control system that rapidly reduces the generator set's output power when a fault or anomaly is detected to maintain system stability and safety. Therefore, the electromechanical imbalance coefficient does not need to capture even the slightest imbalance in power load. The preset threshold range is wider than that for thermal power plants without FCB functionality. Preferably, the preset threshold range for thermal power plants with FCB functionality is 0.3 to 0.4.

[0124] The preset speed threshold for thermal power units with FCB function is the same as that for thermal power units without FCB function, which is 101% of the rated speed of the steam turbine. However, the specific preset speed threshold is set by the rated speed of the steam turbine.

[0125] When the power of a thermal power unit is within a preset threshold and the turbine speed is greater than or equal to the preset speed threshold, the unit with FCB functionality implements zero-power protection. This protection involves closing the turbine's high-pressure and medium-pressure regulating valves. Closing these valves prevents turbine overspeed.

[0126] In one embodiment, if the power of a thermal power unit falls outside a preset power threshold, the zero-power protection system performs a protection reset after a preset duration. This is the process by which the zero-power protection system restores the thermal power unit to normal operation after performing the protection. The zero-power protection system reopens the high-pressure and medium-pressure regulating valves to enable normal operation of the steam turbine. For example, if the preset duration is 1 second and the power of the thermal power unit falls below 0.35, the zero-power protection system performs a protection reset after 1 second, reopening the high-pressure and medium-pressure regulating valves to enable normal operation of the steam turbine.

[0127] In another embodiment, the present application also provides a convenient maintenance function, namely, supporting a maintenance mode for thermal power units. When the thermal power unit is under maintenance, the maintenance panel is deployed to disconnect all communication channels of the thermal power unit for maintenance and inspection. When the maintenance is completed, the maintenance panel is withdrawn, and normal operation of the equipment is restored, thus ensuring the safety and operability of the zero-power protection system.

[0128] To sum up, the zero-power protection method for a thermal power unit provided in the embodiment of the present application meets the power requirements for protecting the thermal power unit through the electromechanical unbalance coefficient and speed of the thermal power unit, thereby fully taking into account the operating status of the steam turbine, and when the electrical parameters of the thermal power unit meet the electrical requirements for protecting the thermal power unit, taking into account the influence of the electrical side of the thermal power unit, and meeting the power requirements and electrical requirements at the same time, the steam turbine and the electrical side are included in the consideration conditions for executing the protection of the thermal power unit, so that it can more comprehensively judge whether it is necessary to execute zero-power protection measures, avoiding the existing technology of relying only on a single electrical side signal for judgment, thereby improving the accuracy of zero-power protection.

[0129] In a second aspect, an embodiment of the present application provides a zero-power protection device for a thermal power unit. Figure 5 FIG. 1 is a block diagram of a zero power protection device for a thermal power plant according to an exemplary embodiment. Figure 5 As shown, the zero power protection device of the thermal power unit includes:

[0130] an obtaining module, configured to obtain, in response to a start-up request of the zero power protection system, an electromechanical unbalance coefficient, electrical parameters, and a rotational speed of the steam turbine of the thermal power unit;

[0131] a protection requirement satisfaction module, configured to satisfy the power requirement for protecting the thermal power unit if the electromechanical unbalance coefficient is within a preset threshold range and the turbine speed is greater than or equal to a preset speed threshold; and satisfy the electrical requirement for protecting the thermal power unit if the electrical parameters satisfy the electrical conditions;

[0132] An execution module executes a zero-power protection measure when the power requirement and the electrical requirement are met simultaneously.

[0133] To summarize, the zero-power protection device for a thermal power unit provided in the present application determines the activation of the zero-power protection system through the mutation amount of the thermal power unit, and executes zero-power protection measures while simultaneously satisfying the judgment conditions on the power side and the judgment conditions on the electrical side. This allows the power and speed of the steam turbine to be fully considered when performing zero-power protection on the thermal power unit, and combines the judgment conditions on the electrical side, thereby improving the accuracy of zero-power protection of the thermal power unit.

[0134] It should be noted that the zero-power protection device for a thermal power unit provided in this embodiment is used to implement the aforementioned embodiments, and details already described will not be repeated. As used above, the terms "module," "unit," "subunit," etc. may refer to a combination of software and / or hardware that implements a predetermined function. Although the devices described in the above embodiments are preferably implemented in software, implementation using hardware, or a combination of software and hardware, is also possible and contemplated.

[0135] In a third aspect, an embodiment of the present application provides an electronic device, Figure 6 FIG is a block diagram of an electronic device according to an exemplary embodiment. Figure 6 As shown, the electronic device may include a processor 81 and a memory 82 storing computer program instructions.

[0136] Specifically, the processor 81 may include a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0137] Among them, the memory 82 may include a large-capacity memory for data or instructions. By way of example and not limitation, the memory 82 may include a hard disk drive (HDD), a floppy disk drive, a solid-state drive (SSD), a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory 82 may include a removable or non-removable (or fixed) medium. Where appropriate, the memory 82 may be inside or outside the data processing device. In a specific embodiment, the memory 82 is a non-volatile memory. In a specific embodiment, the memory 82 includes a read-only memory (ROM) and a random access memory (RAM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable ROM (Programmable Read-Only Memory, PROM for short), an erasable PROM (Erasable Programmable Read-Only Memory, EPROM for short), an electrically erasable PROM (Electrically Erasable Programmable Read-Only Memory, EEPROM for short), an electrically alterable ROM (Electrically Alterable Read-Only Memory, EAROM for short) or a flash memory (FLASH) or a combination of two or more of these. Under appropriate circumstances, the RAM can be a static random access memory (SRAM) or a dynamic random access memory (DRAM), where the DRAM can be a fast page mode dynamic random access memory (FPMDRAM), an extended data output dynamic random access memory (EDODRAM), a synchronous dynamic random access memory (SDRAM), etc.

[0138] The memory 82 may be used to store or cache various data files required for processing and / or communication, as well as possible computer program instructions executed by the processor 81 .

[0139] The processor 81 reads and executes computer program instructions stored in the memory 82 to implement any one of the zero-power protection methods for thermal power generation units in the above embodiments.

[0140] In one embodiment, the zero power protection device of the thermal power unit may further include a communication interface 83 and a bus 80. Figure 6 As shown, the processor 81, the memory 82, and the communication interface 83 are connected via a bus 80 and communicate with each other.

[0141] The communication interface 83 is used to enable communication between the various modules, devices, units, and / or devices in the embodiments of the present application. The communication port 83 can also enable data communication with other components such as external devices, image / data acquisition devices, databases, external storage, and image / data processing workstations.

[0142] Bus 80 includes hardware, software, or both, and couples the components of the thermal power unit zero-power protection device to each other. Bus 80 includes, but is not limited to, at least one of the following: a data bus, an address bus, a control bus, an expansion bus, and a local bus. By way of example and not limitation, bus 80 may include an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low Pin Count (LPC) bus, a memory bus, a MicroChannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local Bus (VLB) bus, or other suitable buses, or a combination of two or more of the above. Bus 80 may include one or more buses, where appropriate. Although embodiments herein describe and illustrate a particular bus, this application contemplates any suitable bus or interconnect.

[0143] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium having a program stored thereon, which, when executed by a processor, implements the zero-power protection method for a thermal power unit provided in the first aspect.

[0144] The readable storage medium may include, but is not limited to, a portable disk, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory, an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0145] In a possible embodiment, the present invention can also be implemented in the form of a program product, which includes program code. When the program product is run on a terminal device, the program code is used to enable the terminal device to execute the steps of the zero-power protection method for thermal power units provided in the first aspect.

[0146] The program code for executing the present invention may be written in any combination of one or more programming languages, and may be executed entirely on the user device, partially on the user device, as an independent software package, partially on the user device and partially on a remote device, or entirely on the remote device.

[0147] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0148] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A zero power protection method for a thermal power unit, characterized in that: The method is applied to a zero power protection system, and the method includes: In response to a start-up request of the zero power protection system, obtaining an electromechanical unbalance coefficient, electrical parameters, and a rotational speed of a steam turbine of the thermal power unit; If the electromechanical unbalance coefficient is within a preset threshold range and the turbine speed is greater than or equal to the preset speed threshold, the power requirement for protecting the thermal power unit is met; if the electrical parameters meet the electrical conditions, the electrical requirements for protecting the thermal power unit are met; When the power requirement and the electrical requirement are simultaneously met, a zero-power protection measure is performed.

2. The zero power protection method for thermal power generation units according to claim 1, characterized in that: The electrical parameters include the power of the thermal power unit, the current of any two phases of the thermal power unit, the effective value of the current, and the delay time of the fault judgment of the thermal power unit. The electrical parameters satisfying the electrical conditions include: During a first preset time period, the power of the thermal power generation unit is greater than or equal to a first preset power threshold; The current of any two phases of the thermal power generation unit is less than a preset first current threshold; Within a second preset time period, the change in the effective value of the current is greater than or equal to a preset second current threshold; The thermal power unit fault judgment delay time is greater than or equal to a preset time threshold; When the thermal power generation unit fails, the power of the thermal power generation unit is less than a second preset power threshold.

3. The zero power protection method for a thermal power plant according to claim 1, characterized in that: The zero power protection measures include: Stop the steam turbine; Turn off the generator outlet switch and demagnetization switch; Start the steam turbine emergency trip system and boiler interlock system.

4. The zero power protection method for a thermal power plant according to claim 3, characterized in that: The thermal power unit includes a steam turbine and has a rapid load reduction function, and the zero power protection measures further include: Close the high-pressure regulating valve and the medium-pressure regulating valve of the steam turbine.

5. The zero power protection method for a thermal power plant according to claim 1, characterized in that: Before responding to the startup request of the zero power protection system, the method further includes: Obtain the active power and operating current of the thermal power unit; If the active power is greater than a preset state power threshold, determining that the operating state of the thermal power unit is an operation state; If the active power is less than the preset state power threshold and the operating current is less than the preset state current threshold, determining that the operating state of the thermal power unit is a shutdown state; If the active power is less than the preset state power threshold, and the operating current is greater than the preset state current threshold, it is determined that the operating state of the thermal power unit is abnormal, and an abnormality alarm is sent.

6. The zero power protection method for a thermal power plant according to claim 5, characterized in that: The thermal power unit includes a transformer, and the method further includes: Receive the voltage and current on the high-voltage side of the transformer; If only the current is received, the abnormal current loop is blocked and a current disconnection alarm is sent; When only the voltage is received, the abnormal voltage circuit is blocked and a voltage disconnection alarm is sent.

7. The zero power protection method for a thermal power plant according to claim 1, characterized in that: The responding to the startup request of the zero power protection system includes: In response to a power mutation amount of the thermal power unit being greater than or equal to a preset power threshold, triggering the start request; and / or In response to the current mutation being greater than or equal to a preset current threshold, the start request is triggered.

8. A zero power protection device for a thermal power unit, characterized in that: The device is applied to a zero power protection system, and comprises: an obtaining module, configured to obtain, in response to a start-up request of the zero power protection system, an electromechanical unbalance coefficient, electrical parameters, and a rotational speed of the steam turbine of the thermal power unit; a protection requirement satisfaction module, configured to satisfy the power requirement for protecting the thermal power unit if the electromechanical unbalance coefficient is within a preset threshold range and the turbine speed is greater than or equal to a preset speed threshold; and satisfy the electrical requirement for protecting the thermal power unit if the electrical parameters satisfy the electrical conditions; An execution module executes a zero-power protection measure when the power requirement and the electrical requirement are met simultaneously.

9. An electronic device, characterized in that: The invention comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the zero-power protection method for a thermal power unit according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the zero-power protection method for a thermal power plant according to any one of claims 1 to 7 is implemented.

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