A unit quick load reduction isolated network operation triggering system and method

Abstract

The application discloses a kind of unit quick load reduction isolated network operation triggering system and method, comprising the following steps: when the positive sequence voltage of main transformer side increases suddenly ΔU H Greater than preset value ΔU Hset While the frequency f of main transformer side is greater than 50.2Hz;The frequency f of main transformer side is greater than over frequency setting value fset or the frequency increment Δf of main transformer side is greater than frequency increment preset value Δf set When any one of the above conditions is met, the active power P G Greater than power setting value setting value P set Then trigger unit quick load reduction isolated network operation protection action, the system and method can enhance the flexibility and safety of generator set operation, improve the risk resistance of local power grid.

Description

Technical Field

[0001] This invention belongs to the field of electrical and thermal control of thermal power units, and relates to a triggering system and method for rapid load reduction and isolated grid operation of a unit. Background Technology

[0002] With the deepening of my country's ultra-high voltage and large power grid planning, transmission lines are widely adopting new technologies such as compact lines and long-distance transmission, effectively reducing the number of lines laid, saving corridor resources, and providing a solid guarantee for the stable transmission of power from the power grid. However, coastal cities and island areas in my country are frequently hit by extreme natural disasters such as typhoons, which can easily trigger power grid failures, causing generator units to be unable to deliver power normally and forcing them to shut down. This not only damages the thermal equipment of the units and affects their service life, but also presents the problem of difficulty in quickly restarting the units after the power grid is restored, which greatly restricts the construction progress of my country's local strong power grid. Against this background, in order to improve the rapid recovery capability of generator units under power grid failure scenarios, a rapid load reduction islanding operation triggering system for generator units is being developed. This system aims to enhance the flexibility and safety of generator unit operation, and at the same time, it has important practical significance for improving the risk resistance capability of local power grids and strengthening the power grid security defense line. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a system and method for triggering rapid load reduction and isolated grid operation of generator units. This system and method can enhance the flexibility and safety of generator unit operation and improve the risk resistance of the local power grid.

[0004] To achieve the above objectives, this invention discloses a method for triggering rapid load reduction and isolated grid operation of a generating unit, comprising the following steps: When the positive sequence voltage on the main transformer side suddenly increases by ΔU H Greater than the preset value △U Hset Meanwhile, the main transformer side frequency f is greater than 50.2Hz; the main transformer side frequency f is greater than the over-frequency setting fset or the main transformer side frequency increment Δf is greater than the preset frequency increment Δf. set When any of the above conditions are met, the active power P on the main transformer side will also be... G Greater than the power setpoint P set This will trigger the unit's rapid load reduction and isolated grid operation protection action.

[0005] This invention discloses a unit rapid load reduction islanding operation triggering system, including a first ratio-large module, a second ratio-large module, a third ratio-large module, a fourth ratio-large module, a fifth ratio-large module, a first OR module, a second OR module, a first AND module, a second AND module, a first TON module, a second TON module, and a start protection output terminal; The positive sequence voltage surge ΔU on the main transformer side H and preset value △UHset The main transformer side frequency f and 50.2Hz are connected to the input terminal of the first ratio-enhancing module. The main transformer side frequency f and over-frequency setting fset are connected to the input terminal of the third ratio-enhancing module. The main transformer side frequency increment Δf and frequency increment preset value Δf are also connected. set Connected to the input terminal of the fourth large module, the active power P on the main transformer side G及 Power setpoint P set The output terminals of the first and second proportional modules are connected to the input terminal of the first AND module. The output terminals of the third and fourth proportional modules are connected to the input terminal of the first OR module. The output terminals of the first AND module and the first OR module are connected to the input terminal of the second OR module. The output terminal of the fifth proportional module is connected to the input terminal of the first TON module. The output terminals of the first TON module and the second OR module are connected to the input terminal of the second AND module. The output terminal of the second AND module is connected to the start protection output terminal via the second TON module.

[0006] Furthermore, the power setpoint P set Set to 20% of the unit's rated power.

[0007] Furthermore, the setpoint ΔU for the positive sequence voltage surge on the main transformer side... Hset It is 1.2 V.

[0008] Furthermore, the preset value Δf of the frequency increment on the main transformer side set It is 0.1 Hz.

[0009] Furthermore, the overfrequency setpoint f set It is 50.4 Hz.

[0010] Furthermore, the start-up protection output terminal is connected to the electrical side, boiler side, turbine side, and DEH side of the unit.

[0011] Furthermore, the electrical side includes an electrical side circuit breaker, a diesel generator system, and a DC power supply system.

[0012] Furthermore, the boiler side includes a pulverizing system, a flue gas system, and a steam-water system.

[0013] Furthermore, the turbine side includes a bypass system, a condensate system, a circulating water system, a vacuum system, a feedwater system, and an auxiliary steam system; The DEH side includes a coordinated control method and a control loop.

[0014] The present invention has the following beneficial effects: The unit's rapid load reduction and isolated grid operation triggering system and method described in this invention, through real-time judgment of the grid-side operating status, enables the unit to actively disconnect from the grid and quickly switch operating modes when a grid fault occurs, reducing unit output and operating in isolated grid mode with its own auxiliary power. Simultaneously, combined with the key auxiliary machine control strategies of the unit's auxiliary system, it achieves a safe and stable transition of unit operating parameters, ensuring safe unit operation. Compared to the operational hazards such as overspeed and speed oscillation caused by grid faults directly leading to unit tripping, this invention effectively avoids such problems and can promptly restore power to the grid after grid functionality is restored, helping the large grid to deliver power to users in a timely manner. Attached Figure Description

[0015] 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.

[0016] Figure 1 This is a system diagram of the present invention; Figure 2 This is a structural diagram of the generator set. Detailed Implementation

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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)."

[0023] 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.

[0024] 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.

[0025] Example 1 refer to Figure 1 and Figure 2 The unit rapid load reduction islanding operation triggering system of the present invention includes a first ratio module, a second ratio module, a third ratio module, a fourth ratio module, a fifth ratio module, a first OR module, a second OR module, a first AND module, a second AND module, a first TON module, a second TON module, and a start protection output terminal; The positive sequence voltage surge ΔU on the main transformer side H and preset value △U Hset The main transformer side frequency f and 50.2Hz are connected to the input terminal of the first ratio-enhancing module. The main transformer side frequency f and over-frequency setting fset are connected to the input terminal of the third ratio-enhancing module. The main transformer side frequency increment Δf and frequency increment preset value Δf are also connected. set Connected to the input terminal of the fourth large module, the active power P on the main transformer side G及 Power setpoint P set The output terminals of the first and second largest modules are connected to the input terminal of the first AND module. The output terminals of the third and fourth largest modules are connected to the input terminal of the first OR module. The output terminals of the first AND module and the first OR module are connected to the input terminal of the second OR module. The output terminal of the fifth largest module is connected to the input terminal of the first TON module. The output terminals of the first TON module and the second OR module are connected to the input terminal of the second AND module. The output terminal of the second AND module is connected to the start-up protection output terminal via the second TON module. The start-up protection output terminal is connected to the electrical side, boiler side, turbine side, and DEH side of the unit. The electrical side includes an electrical circuit breaker, a diesel generator system, and a DC power supply system. The boiler side includes a pulverizing system, a flue gas system, and a steam-water system. The turbine side includes a bypass system, a condensate system, a circulating water system, a vacuum system, a feedwater system, and an auxiliary steam system. The DEH side includes a coordinated control method and a control loop.

[0026] Example 2 The method for triggering rapid load reduction and isolated grid operation of generating units according to the present invention includes the following steps: When the positive sequence voltage on the main transformer side suddenly increases by ΔU H Greater than the preset value △U Hset Meanwhile, the main transformer side frequency f is greater than 50.2Hz; the main transformer side frequency f is greater than the over-frequency setting fset or the main transformer side frequency increment Δf is greater than the preset frequency increment Δf. set When any of the above conditions are met, the active power P on the main transformer side will also be... G Greater than the power setpoint P set This will trigger the unit's rapid load reduction and isolated grid operation protection action.

[0027] To better align with actual production needs, the power setpoint P is set to... set Set to 20% of the unit's rated power, the positive sequence voltage surge setpoint ΔU on the main transformer side. Hset The preset value for the frequency increment on the main transformer side is 1.2 V, Δf. set The over-frequency setpoint is 0.1 Hz, f. set It is 50.4 Hz. Combined with... Figure 1 The function triggering logic shown triggers the unit's rapid load reduction and isolated grid operation function when all parameters and judgment logic are satisfied.

[0028] like Figure 2 As shown, when the unit's rapid load reduction and isolated grid operation function is triggered, the unit needs to quickly coordinate the rapid switching of the control electrical system and the rapid load change of key auxiliary equipment in the auxiliary system, including but not limited to the following equipment and systems.

[0029] When the unit experiences rapid load shedding and isolated grid operation on the DEH side, the unit's control loop is quickly switched from power control to speed control to ensure that the self-contained auxiliary power supply can quickly stabilize the turbine speed and guarantee the power quality of the auxiliary power supply. Simultaneously, the unit's coordinated control automatic mode is switched to basic control mode, which improves the controllability and safety of unit operation under grid fault conditions.

[0030] The electrical side includes electrical circuit breakers, diesel generator systems, and DC power supply systems. When the function is triggered, the generator output grid-connected circuit breaker quickly trips without tripping the unit. Simultaneously, the fast-switching of the generator output auxiliary power circuit breaker is locked, maintaining the unit's operation with auxiliary power. Furthermore, to prevent the unit from failing to enter islanded operation, the diesel generator is interlocked to start, and the DC power supply is ensured to be reliable, guaranteeing a smooth and safe shutdown of the unit.

[0031] The boiler side includes a pulverizing system, a flue gas system, and a steam-water system. The pulverizing system quickly shuts down excess pulverizing operations based on the unit load, simultaneously adjusting the unit's primary air pressure and furnace negative pressure via the flue gas system. Additionally, to prevent a rapid drop in steam temperature due to the rapid reduction in fuel quantity, the superheater and reheater desuperheating water regulating valves are interlocked and shut off to prevent accidental desuperheating water spraying that could exacerbate the sudden drop in steam temperature.

[0032] The turbine side includes a bypass system, condensate system, circulating water system, vacuum system, feedwater system, and auxiliary steam system. The bypass system rapidly opens to release pressure upon triggering of operating conditions, then switches to constant pressure regulation mode after pressure stabilizes to ensure stable inlet pressure and thus stable turbine inlet steam parameters. The rapid opening of the bypass system causes a large amount of heat to enter the condenser, resulting in a surge in condenser heat. This rapidly increases the condensate flow rate and activates the standby circulating water pump and vacuum pump to ensure sufficient cooling water for the condenser, while also supplying sufficient desuperheating water to the low-pressure bypass and condenser. Furthermore, due to the rapid reduction in unit load, the auxiliary steam source parameters decrease, prompting a rapid switch from low-pressure to high-pressure steam to meet the normal steam demand of users such as feedwater pumps and turbine shaft seals, ensuring safe unit operation.

[0033] This invention has the following characteristics: This invention achieves rapid fault identification and graded triggering through a triple criterion that integrates multiple parameters such as voltage, frequency, and power angle. At the same time, it adopts a coordinated basic control method to maintain stable main steam pressure on the boiler side and switch to closed-loop speed control on the turbine side. Combined with constant voltage regulation and bypass rapid action of the excitation system, it effectively suppresses drastic fluctuations in parameters under this operating condition.

[0034] This invention enables self-contained plant power operation under grid faults by means of rapid load reduction and rapid output reduction of auxiliary equipment; on the other hand, the unit can quickly restore grid-connected load after the fault, providing stable support power for grid black start, and significantly enhancing the reliability and flexibility of system power supply.

[0035] 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 the unit's rapid load reduction islanding operation triggering method, for example, including: when the positive sequence voltage on the main transformer side suddenly increases by ΔU... H Greater than the preset value △U Hset Meanwhile, the main transformer side frequency f is greater than 50.2Hz; the main transformer side frequency f is greater than the over-frequency setting fset or the main transformer side frequency increment Δf is greater than the preset frequency increment Δf. set When any of the above conditions are met, the active power P on the main transformer side will also be... G Greater than the power setpoint P setThis triggers the unit's rapid load reduction and islanded operation protection action. The memory may include main memory, such as high-speed random access memory, or 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, or an extended industry-standard architecture bus. The bus can be categorized as an address bus, data bus, and control bus. The memory stores 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.

[0036] Example 4 A computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the unit's rapid load reduction islanding operation triggering method, for example including: when the positive sequence voltage on the main transformer side suddenly increases by ΔU... H Greater than the preset value △U Hset Meanwhile, the main transformer side frequency f is greater than 50.2Hz; the main transformer side frequency f is greater than the over-frequency setting fset or the main transformer side frequency increment Δf is greater than the preset frequency increment Δf. set When any of the above conditions are met, the active power P on the main transformer side will also be... G Greater than the power setpoint P set This triggers the unit's rapid load reduction and islanded operation protection action. 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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 triggering rapid load reduction and isolated grid operation of a generating unit, characterized in that, Includes the following steps: When the positive sequence voltage on the main transformer side suddenly increases by ΔU H Greater than the preset value △U Hset Meanwhile, the main transformer side frequency f is greater than 50.2Hz; the main transformer side frequency f is greater than the over-frequency setting fset or the main transformer side frequency increment Δf is greater than the preset frequency increment Δf. set When any of the above conditions are met, the active power P on the main transformer side will also be... G Greater than the power setpoint P set This will trigger the unit's rapid load reduction and isolated grid operation protection action.

2. A unit rapid load reduction islanding operation triggering system, characterized in that, It includes a first larger module, a second larger module, a third larger module, a fourth larger module, a fifth larger module, a first OR module, a second OR module, a first AND module, a second AND module, a first TON module, a second TON module, and a start protection output terminal; The positive sequence voltage surge ΔU on the main transformer side H and preset value △U Hset The main transformer side frequency f and 50.2Hz are connected to the input terminal of the first ratio-enhancing module. The main transformer side frequency f and over-frequency setting fset are connected to the input terminal of the third ratio-enhancing module. The main transformer side frequency increment Δf and frequency increment preset value Δf are also connected. set Connected to the input terminal of the fourth large module, the active power P on the main transformer side G及 Power setpoint P set The output terminals of the first and second proportional modules are connected to the input terminal of the first AND module. The output terminals of the third and fourth proportional modules are connected to the input terminal of the first OR module. The output terminals of the first AND module and the first OR module are connected to the input terminal of the second OR module. The output terminal of the fifth proportional module is connected to the input terminal of the first TON module. The output terminals of the first TON module and the second OR module are connected to the input terminal of the second AND module. The output terminal of the second AND module is connected to the start protection output terminal via the second TON module.

3. The unit rapid load reduction islanding operation triggering system according to claim 2, characterized in that, The power setpoint P set Set to 20% of the unit's rated power.

4. The unit rapid load reduction islanding operation triggering system according to claim 2, characterized in that, The positive sequence voltage surge setpoint ΔU on the main transformer side Hset It is 1.2 V.

5. The unit rapid load reduction islanding operation triggering system according to claim 2, characterized in that, The preset value of frequency increment on the main transformer side Δf set It is 0.1 Hz.

6. The unit rapid load reduction islanding operation triggering system according to claim 2, characterized in that, The overfrequency setpoint f set It is 50.4 Hz.

7. The unit rapid load reduction islanding operation triggering system according to claim 2, characterized in that, The start-up protection output terminal is connected to the electrical side, boiler side, turbine side and DEH side of the unit.

8. The unit rapid load reduction islanding operation triggering system according to claim 7, characterized in that, The electrical side includes electrical side circuit breakers, diesel generator systems, and DC power supply systems.

9. The unit rapid load reduction islanding operation triggering system according to claim 7, characterized in that, The boiler side includes a pulverizing system, a flue gas system, and a steam-water system.

10. The unit rapid load reduction islanding operation triggering system according to claim 7, characterized in that, The turbine side includes a bypass system, a condensate system, a circulating water system, a vacuum system, a feedwater system, and an auxiliary steam system; The DEH side includes a coordinated control method and a control loop.

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