WO2024067120A1 - 抑制低频振荡的方法和系统 - Google Patents

抑制低频振荡的方法和系统 Download PDF

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Publication number
WO2024067120A1
WO2024067120A1 PCT/CN2023/118761 CN2023118761W WO2024067120A1 WO 2024067120 A1 WO2024067120 A1 WO 2024067120A1 CN 2023118761 W CN2023118761 W CN 2023118761W WO 2024067120 A1 WO2024067120 A1 WO 2024067120A1
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Prior art keywords
frequency
oscillation
low
function
unit
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PCT/CN2023/118761
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English (en)
French (fr)
Inventor
刘磊
杨振勇
康静秋
高明帅
邢智炜
尤默
陈振山
马宁
李展
赖联坤
尚勇
高爱国
史春红
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华北电力科学研究院有限责任公司
国家电网有限公司
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Publication of WO2024067120A1 publication Critical patent/WO2024067120A1/zh

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks

Definitions

  • the present application relates to the technical field of frequency control of generator sets, for example, to a method and system for suppressing low-frequency oscillations.
  • a large number of new energy generation units are connected. Due to its random, intermittent and volatile characteristics, and the insufficient peak-shaving capacity of the power system, the network frequency fluctuates frequently. Taking a regional power grid as an example, the number of frequency regulation actions (i.e., the network frequency exceeds the dead zone ⁇ 2rpm) in August, September and October 20xx was 65, 319 and 164 times respectively, which increased by 5-8 times compared with other months and 8-10 times compared with the same months in previous years. On the other hand, a large number of thermal power units have completed flexibility transformation and are operating in the deep peak-shaving range.
  • the unit's rotational inertia continues to decrease, and the anti-disturbance ability continues to decrease.
  • the simultaneous action of external or internal disturbances makes it easy for the unit to trigger unit-level forced oscillation, especially the frequent low-frequency oscillation accidents of the generator unit.
  • the supporting and regulating role of the thermal power unit is not only not reflected, but also brings huge hidden dangers to the stability of the system, endangering the safe operation of the unit and the power grid.
  • Low-frequency oscillation of power system refers to the phenomenon that when the power system is disturbed, the relative swing between the rotors of the synchronous generators running in parallel causes the power, voltage, power angle and other electrical quantities in the system to oscillate to varying degrees.
  • the frequency of this continuous oscillation is often between 0.2 and 2.5 Hz, so it is called low-frequency oscillation.
  • the oscillation frequency is between 0.2 and 0.7 Hz, it is called the interval oscillation mode. This mode is the oscillation of the machine group between two regions. The oscillation power is transmitted to the entire system through the interconnection line. The harm of the interval oscillation mode is generally relatively large.
  • the problem of low-frequency oscillation on the source side is mainly caused by the following two factors: on the one hand, external objective factors, due to the access of a large number of new energy units to the power grid, their inherent fluctuation characteristics lead to frequent fluctuations in the network frequency; on the other hand, due to problems such as the operating conditions of the unit system and the parameters of the frequency modulation control loop, the frequency modulation loop fluctuates sharply, resulting in a significant decrease in the stability of the unit side, which is very prone to low-frequency oscillation problems.
  • FIG1 The typical control logic used in the unit frequency control in the related art is shown in FIG1 .
  • the load command of the automatic generation control (AGC) and the frequency of the unit side are superimposed as the set point (SP) of the proportional-integral-differential (PID) after the frequency difference function F1 (x).
  • SP set point
  • PID proportional-integral-differential
  • the actual power of the unit is used as the PID controlled variable.
  • the control output of the PID is superimposed with the action command of the frequency difference function F2 (x) as the comprehensive flow command, which acts on the valve control of the steam turbine.
  • the frequency difference function F1 (x) and the frequency difference function F2 (x) both act on the load set point and the comprehensive flow command of the PID at the same time, so that the valve opening is increased, the steam intake of the steam turbine is increased, and the output of the steam turbine is increased, and the active power generated by the generator is increased; on the contrary, when the grid frequency is higher than 50.033Hz, the valve opening is reduced, the steam intake of the steam turbine is reduced, and the active power generated by the generator is reduced.
  • the unit actively changes its output according to the frequency changes on the source side, actively supporting the stability of the grid frequency.
  • the frequency control strategy of thermal power units in the above-mentioned related technologies does not have an active defense control strategy for low-frequency oscillation of the unit caused by reciprocating frequency fluctuations.
  • the stability of the control system of the thermal power unit is reduced due to large and repeated fluctuations in the external network frequency and its own system reasons, and low-frequency oscillation occurs, it is impossible to actively intervene at the source side drive end to take necessary defenses, and it is impossible to prevent the oscillation from being further amplified, which leads to a significant decrease in the stability of the system.
  • the present application provides a method and system for suppressing low-frequency oscillations, which solves the problem that low-frequency oscillations on the source side cannot be autonomously monitored and actively defended on the source side, thereby largely avoiding the occurrence of low-frequency oscillations.
  • an embodiment of the present application provides a system for suppressing low-frequency oscillations, the system comprising: a frequency modulation control loop and an oscillation suppression loop, the frequency modulation control loop and the oscillation suppression loop being connected, the oscillation suppression loop comprising an oscillation determination unit, a function switching switch and a function unit, the oscillation determination unit being configured to perform low-frequency oscillation determination based on the actual power of the unit output by the frequency modulation control loop and the unit-side frequency signal; the oscillation determination unit being configured to: in response to the low-frequency oscillation not occurring, control the function switching switch to connect the frequency difference functions F1 (x) and F2 (x) with the frequency modulation control loop, so that the unit-side frequency signal is input into the frequency modulation control loop after passing through the frequency difference functions F1 (x) and F2 (x); in response to the occurrence of the low-frequency oscillation, control the function switching switch to select a function in the function unit according to the intensity level of the low-frequency oscillation
  • the oscillation determination unit is further configured to: in response to the occurrence of the low-frequency oscillation, determine the low-frequency oscillation intensity level according to low-frequency oscillation characteristic quantities, wherein the characteristic quantities include oscillation amplitude, oscillation period and oscillation duration.
  • the low-frequency oscillation intensity level is determined to be a low-intensity level
  • the oscillation amplitude of the load is greater than 8 MW
  • the oscillation period is less than 5 s and greater than 0.2 s
  • the duration is greater than 15 s
  • the low-frequency oscillation intensity level is determined to be a high-intensity level.
  • the oscillation determination unit is configured to control the function switching switch to select a function in the function unit according to the low-frequency oscillation intensity level in the following manner: determining that the low-frequency oscillation intensity level is a low intensity level, and controlling the function switching switch to select a suppression function unit in the function unit; the suppression function unit is configured to suppress the unit side frequency signal passing through the frequency difference functions F1 (x) and F2 (x) and then input it into the frequency modulation control loop, so that the starting section of the frequency modulation action is performed according to the action values of the frequency difference functions F1 (x) and F2 (x).
  • the oscillation determination unit is configured to control the function switching switch to select a function in the function unit according to the low-frequency oscillation intensity level in the following manner: determine that the low-frequency oscillation intensity level is a medium intensity level, and control the function switching switch to select an emergency landing function unit in the function unit; the emergency landing function unit is configured to perform emergency landing processing on the unit side frequency signal passing through the frequency difference functions F1 (x) and F2 (x) and then input it into the frequency modulation control loop, so as to realize the function of significantly attenuating the frequency modulation action amplitude according to the frequency modulation load.
  • the oscillation determination unit is configured to control the function switching switch to select a function in the function unit according to the low-frequency oscillation intensity level in the following manner: determining that the low-frequency oscillation intensity level is a high intensity level, controlling the function switching switch to select a blocking function unit in the function unit; the blocking function unit is configured to block the unit side frequency signal from passing through the frequency difference functions F1 (x) and F2 (x) and then input into the frequency modulation control loop, thereby realizing a temporary cutting off function of the frequency modulation function of the frequency modulation control loop.
  • An embodiment of the present application provides a method for suppressing low-frequency oscillations, the method comprising: determining low-frequency oscillations based on the actual power of the unit output by the frequency modulation control loop and the unit-side frequency signal; in response to the low-frequency oscillation not occurring, controlling a function switching switch to connect the frequency difference functions F1 (x) and F2 (x) with the frequency modulation control loop, so that the unit-side frequency signal passes through the frequency difference functions F1 (x) and F2 (x) and is input into the frequency modulation control loop; in response to the occurrence of the low-frequency oscillation, controlling the function switching switch to select a function in a function unit according to the intensity level of the low-frequency oscillation; based on the selected function, processing the unit-side frequency signal after passing through the frequency difference functions F1 (x) and F2 (x), and inputting the processed unit-side frequency signal into the frequency modulation control loop to achieve low-frequency oscillation suppression.
  • the method further includes: in response to the occurrence of the low-frequency oscillation, determining the intensity level of the low-frequency oscillation according to low-frequency oscillation characteristic quantities, wherein the characteristic quantities include oscillation amplitude, oscillation period and oscillation duration.
  • the low-frequency oscillation intensity level is determined to be a low-intensity level
  • the oscillation amplitude of the load is greater than 5MW and less than 8MW
  • the oscillation period is less than 5s and greater than 0.2s
  • the duration is greater than 10s
  • the low-frequency oscillation intensity level is determined to be a medium-intensity level
  • the oscillation amplitude of the load is greater than 8MW
  • the oscillation period is less than 5s and greater than 0.2s
  • the duration is greater than 15s
  • the low-frequency oscillation intensity level is determined to be a high-intensity level.
  • the function of the function switching switch selection function unit is controlled according to the low-frequency oscillation intensity level, including: determining that the low-frequency oscillation intensity level is a low intensity level, controlling the function switching switch to select the suppression function unit in the function unit, the suppression function unit suppresses the unit side frequency signal passing through the frequency difference functions F1 (x) and F2 (x) and then inputs it into the frequency modulation control loop, so that the starting section of the frequency modulation action is performed according to the action values of the frequency difference functions F1 (x) and F2 (x).
  • the function of controlling the function switching switch to select the function in the function unit according to the low-frequency oscillation intensity level includes: determining that the low-frequency oscillation intensity level is a medium intensity level, controlling the function switching switch to select the forced landing function unit in the function unit, the forced landing function unit performs forced landing processing on the unit side frequency signal passing through the frequency difference functions F1 (x) and F2 (x) and then inputs it into the frequency modulation control loop, thereby realizing the function of significantly attenuating the frequency modulation action amplitude according to the frequency modulation load.
  • controlling the function of the function switching switch to select the function in the function unit according to the low-frequency oscillation intensity level includes: determining that the low-frequency oscillation intensity level is a high-intensity level, controlling the function switching switch to select a blocking function unit in the function unit, the blocking function unit blocking the unit side frequency signal from passing through the frequency difference functions F1 (x) and F2 (x) and then inputting into the frequency modulation control loop, thereby realizing a temporary cutting off function of the frequency modulation function of the frequency modulation control loop.
  • An embodiment of the present application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method of the above embodiment when executing the computer program.
  • An embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method of the above embodiment is implemented.
  • the embodiment of the present application also provides a computer program product, including a computer program/instruction, which implements the method of the above embodiment when the computer program/instruction is executed by a processor.
  • FIG1 is a typical control logic diagram of existing unit frequency control
  • FIG2 is a schematic diagram of a system structure for suppressing low-frequency oscillations provided in an embodiment of the present application
  • Figure 3 is a comparison curve of the low-frequency oscillation of the unit and after the suppression function is triggered
  • FIG4 is a comparison curve diagram of the low-frequency oscillation of the unit and after the forced landing function is triggered;
  • FIG5 is a comparison curve diagram of the low-frequency oscillation of the unit and after the blocking function is triggered
  • FIG6 is a schematic flow chart of a method for suppressing low-frequency oscillation provided in an embodiment of the present application.
  • FIG7 is a schematic flow chart of a method for suppressing low-frequency oscillation provided by another embodiment of the present application.
  • FIG8 is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application.
  • FIG. 2 it is a schematic diagram of the system structure for suppressing low-frequency oscillations provided in an embodiment of the present application.
  • the system includes: a frequency modulation control loop 100 and an oscillation suppression loop 400.
  • the frequency modulation control loop 100 and the oscillation suppression loop 400 are connected.
  • the oscillation suppression loop 400 of the present application includes an oscillation determination unit 200, function switching switches S1 and S2, and a function unit 300.
  • the frequency modulation control loop 100 is the same as the frequency modulation control loop in FIG. 1 , except that the grid frequency inputs of the two summing units in the frequency modulation control loop 100 are controlled by the oscillation suppression loop 400 .
  • the oscillation determination unit 200 is configured to perform low frequency oscillation determination based on the actual unit power output by the frequency modulation control loop 100 and the unit side frequency signal (ie, the grid frequency in FIG. 2 ), that is, to determine whether low frequency oscillation occurs.
  • the oscillation determination unit 200 determines that low-frequency oscillation does not occur, the oscillation determination unit 200 controls the function switching switches S1 and S2 so that the frequency signal on the unit side acts on the frequency modulation control loop 100 after passing through the frequency difference functions F1 (x) and F2 (x). As shown in FIG. 2, the function switching switches S1 and S2 can be switched to side 1, that is, the frequency modulation control loop 100 can operate in the original working mode.
  • the oscillation determination unit 200 When the oscillation determination unit 200 determines that low-frequency oscillation occurs, the oscillation determination unit 200 will switch the function switches S1 and S2 according to the low-frequency oscillation intensity level control function to select the corresponding function in the function unit 300, and perform corresponding processing on the unit side frequency signal after passing through the frequency difference functions F1 (x) and F2 (x) and then act on the frequency modulation control loop 100 to achieve low-frequency oscillation suppression.
  • the oscillation determination unit 200 may continue to determine the intensity level of the low-frequency oscillation based on a low-frequency oscillation characteristic quantity, where the characteristic quantity may include an oscillation amplitude, an oscillation period, and an oscillation duration.
  • the above-mentioned low-frequency oscillation intensity level may include three levels: low, medium and high.
  • the oscillation determination unit 200 determines that the low-frequency oscillation intensity level is a low intensity level; when the oscillation amplitude of the load is greater than 5MW and less than 8MW, the oscillation period is less than 5s and greater than 0.2s, and the duration is greater than 10s, the oscillation determination unit 200 determines that the low-frequency oscillation intensity level is a medium intensity level (dangerous level); when the oscillation amplitude of the load is greater than 8MW, the oscillation period is less than 5s and greater than 0.2s, and the duration is greater than 15s, the oscillation determination unit 200 determines that the low-frequency oscillation intensity level is a high intensity level (extremely dangerous level).
  • the oscillation determination unit 200 determines that the low-frequency oscillation that occurs is of a low-intensity level
  • the oscillation determination unit 200 will control the function switching switches S1 and S2 to switch both to side 2, even if they are both switched to the suppression function unit in the function unit 300.
  • the suppression function unit will process the unit-side frequency signal passing through the frequency difference functions F1 (x) and F2 (x) and then act on the frequency modulation control loop 100, thereby realizing that the starting section of the frequency modulation action of the frequency modulation control loop 100 is performed according to the action values of the frequency difference functions F1 (x) and F2 (x).
  • the oscillation determination unit 200 when the oscillation determination unit 200 determines that the low-frequency oscillation is of a medium intensity level, the oscillation determination unit 200 will control the function switching switches S1 and S2 to switch both to side 3, even if they are both switched to the forced landing function unit in the function unit 300.
  • the forced landing function unit will process the unit side frequency signal passing through the frequency difference functions F1 (x) and F2 (x) and act on the frequency modulation control loop 100, thereby realizing the function of significantly attenuating the frequency modulation action amplitude according to the frequency modulation load.
  • the oscillation determination unit 200 determines that the low-frequency oscillation that occurs is of a high intensity level
  • the oscillation The determination unit 200 controls the function switching switches S1 and S2 to switch to side 4. Even if they are both switched to the blocking function unit in the function unit 300, the blocking function unit will block the frequency signal on the unit side from being input into the frequency modulation control loop 100 after passing through the frequency difference functions F1 (x) and F2 (x), and the frequency modulation function of the frequency modulation control loop 100 will be temporarily blocked.
  • Figure 3 is a comparison curve diagram of the low-frequency oscillation of the unit and after the suppression function is triggered
  • Figure 4 is a comparison curve diagram of the low-frequency oscillation of the unit and after the forced landing function is triggered
  • Figure 5 is a comparison curve diagram of the low-frequency oscillation of the unit and after the blocking function is triggered.
  • the oscillation amplitude reaches 212.2MW-208.8MW, and the difference between the maximum and minimum oscillation values is 3.4MW.
  • the oscillation load drops rapidly to between 210MW and 211MW, and the difference between the maximum and minimum oscillation values is less than 1MW, and there is no periodic fluctuation phenomenon.
  • the oscillation amplitude reaches 214.6MW-207.9MW, and the oscillation maximum and minimum values are 6.7MW apart.
  • the oscillation load drops rapidly to between 209.5MW-210.5MW, and the oscillation maximum and minimum values are less than 1MW apart, and there is no periodic fluctuation phenomenon.
  • the oscillation amplitude reaches 213.8MW-203.9MW, and the maximum and minimum oscillation values are 9.9MW apart.
  • the oscillation load drops rapidly to between 209MW-211MW, and the maximum and minimum oscillation values are only less than 2MW apart, and there is no periodic fluctuation phenomenon.
  • the system for suppressing low-frequency oscillations solves the problem that the low-frequency oscillation problem on the source side cannot be autonomously monitored and actively defended, and greatly avoids the occurrence of low-frequency oscillation accidents.
  • the three-level suppression method of the present application can effectively avoid the problem of reduced frequency modulation performance caused by misjudgment of low-frequency oscillations, and the situation where the frequency modulation control loop must be cut off as long as a low-level oscillation is determined will not occur. That is, the three-level suppression method of the present application is of great significance to the safety and performance improvement of the unit frequency modulation.
  • FIG6 is a flow chart of a method for suppressing low-frequency oscillation provided by an embodiment of the present application. The method comprises the following steps:
  • Step S601 low-frequency oscillation is determined based on the actual power of the unit output by the frequency modulation control loop and the frequency signal on the unit side. If no low-frequency oscillation occurs, the process proceeds to step S602; otherwise, the process proceeds to step S603.
  • Step S602 Control the function switching switch to connect the frequency difference functions F 1 (x) and F 2 (x) with the frequency modulation control loop, so that the unit side frequency signal passes through the frequency difference functions F 1 (x) and F 2 (x) and is then input into the frequency modulation control loop.
  • Step S603 Control the function switch to select the function unit according to the low frequency oscillation intensity level. function.
  • Step S604 Based on the selected function, the unit-side frequency signal after passing through the frequency difference functions F 1 (x) and F 2 (x) is processed, and the processed unit-side frequency signal is input into the frequency modulation control loop to achieve low-frequency oscillation suppression.
  • the method for suppressing low-frequency oscillation provided by the embodiment of the present application solves the problem that the low-frequency oscillation problem on the source side cannot be autonomously monitored and actively defended, and greatly avoids the occurrence of low-frequency oscillation accidents. At the same time, it can effectively avoid the problem of frequency regulation performance degradation caused by misjudgment of low-frequency oscillation, which is of great significance to the safety and performance improvement of unit frequency regulation.
  • FIG. 7 is a flow chart of a method for suppressing low-frequency oscillation provided in another embodiment of the present application. The method includes the following steps.
  • Step S701 low-frequency oscillation is determined based on the actual power of the unit output by the frequency modulation control loop and the frequency signal on the unit side. If no low-frequency oscillation occurs, the process proceeds to step S702; otherwise, the process proceeds to step S703.
  • Step S702 Control the function switching switch to connect the frequency difference functions F 1 (x) and F 2 (x) with the frequency modulation control loop, so that the unit side frequency signal passes through the frequency difference functions F 1 (x) and F 2 (x) and is then input into the frequency modulation control loop.
  • Step S703 In response to the occurrence of low-frequency oscillation, the severity level of the low-frequency oscillation is determined according to the low-frequency oscillation characteristic quantity, wherein the characteristic quantity includes the oscillation amplitude, the oscillation period and the oscillation duration. If the low-frequency oscillation is of low severity level, the process proceeds to step S704; if the low-frequency oscillation is of medium severity level, the process proceeds to step S705; if the low-frequency oscillation is of high severity level, the process proceeds to step S706.
  • the low-frequency oscillation intensity level is judged to be a low-intensity level
  • the load oscillation amplitude is greater than 5MW and less than 8MW
  • the oscillation period is less than 5s and greater than 0.2s
  • the duration is greater than 10s
  • the low-frequency oscillation intensity level is judged to be a medium-intensity level
  • the load oscillation amplitude is greater than 8MW
  • the oscillation period is less than 5s and greater than 0.2s
  • the duration is greater than 15s
  • the low-frequency oscillation intensity level is judged to be a high-intensity level.
  • Step S704 Determine that the low-frequency oscillation intensity level is a low-intensity level, control the function switching switch to select the suppression function unit in the function unit, the suppression function unit suppresses the unit side frequency signal passing through the frequency difference functions F1 (x) and F2 (x) and inputs it into the frequency modulation control loop, and implements the starting section of the frequency modulation action according to the action values of the frequency difference functions F1 (x) and F2 (x).
  • Step S705 Determine that the low-frequency oscillation intensity level is a medium intensity level, control the function switching switch to select the forced landing function unit in the function unit, the forced landing function unit performs forced landing processing on the unit side frequency signal passing through the frequency difference functions F1 (x) and F2 (x) and inputs it into the frequency modulation control loop, so as to realize the function of greatly attenuating the frequency modulation action amplitude according to the frequency modulation load.
  • Step S706 Determine that the low-frequency oscillation severity level is a high severity level, and control the function switching switch to select a blocking function unit in the function unit, wherein the blocking function unit blocks the frequency signal on the unit side from passing through the blocking function unit.
  • the frequency difference functions F 1 (x) and F 2 (x) are then input into the frequency modulation control loop, and the frequency modulation function of the frequency modulation control loop will be temporarily blocked.
  • the method for suppressing low-frequency oscillation provided by the embodiment of the present application solves the problem that the low-frequency oscillation problem on the source side cannot be autonomously monitored and actively defended, and greatly avoids the occurrence of low-frequency oscillation accidents. At the same time, it can effectively avoid the problem of frequency regulation performance degradation caused by misjudgment of low-frequency oscillation, which is of great significance to the safety and performance improvement of unit frequency regulation.
  • FIG8 is a schematic diagram of an electronic device provided in an embodiment of the present application.
  • the electronic device shown in FIG8 is a general data processing device, which includes a general computer hardware structure, which at least includes a processor 801 and a memory 802.
  • the processor 801 and the memory 802 are connected via a bus 803.
  • the memory 802 is suitable for storing one or more instructions or programs executable by the processor 801.
  • the one or more instructions or programs are executed by the processor 801 to implement the steps in the above-mentioned method of suppressing low-frequency oscillation.
  • the processor 801 may be an independent microprocessor or a collection of one or more microprocessors. Thus, the processor 801 executes the commands stored in the memory 802 to execute the method flow of the embodiment of the present application as described above to realize the processing of data and the control of other devices.
  • the bus 803 connects the above-mentioned multiple components together, and at the same time connects the above-mentioned components to the display controller 804 and the display device and the input/output (I/O) device 805.
  • the I/O device 805 may be a mouse, a keyboard, a modem, a network interface, a touch input device, a somatosensory input device, a printer, and other devices known in the art. Typically, the I/O device 805 is connected to the system via an I/O controller 806.
  • the memory 802 can store software components, such as an operating system, a communication module, an interaction module, and an application program. Each of the modules and applications described above corresponds to a set of executable program instructions that implement one or more functions and methods described in the application embodiments.
  • the embodiment of the present application also provides a computer-readable storage medium on which a computer program is stored.
  • a computer program is stored on which a computer program is stored.
  • the steps of the above-mentioned method for suppressing low-frequency oscillation are implemented.
  • An embodiment of the present application further provides a computer program product, including a computer program/instruction, which implements the steps of the above-mentioned method for suppressing low-frequency oscillation when executed by a processor.
  • the method and device for suppressing low-frequency oscillation proposed in this application solves the problem that the low-frequency oscillation problem on the source side cannot be autonomously monitored and actively defended, and greatly avoids the occurrence of low-frequency oscillation accidents. At the same time, it can effectively avoid the problem of frequency regulation performance degradation caused by misjudgment of low-frequency oscillation, which is of great significance to the safety and performance improvement of unit frequency regulation.
  • the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of one or more embodiments including The form of a computer program product implemented on a computer-usable storage medium (including but not limited to disk storage, portable compact disc read-only memory (CD-ROM), optical storage, etc.) containing computer-usable program code.
  • a computer-usable storage medium including but not limited to disk storage, portable compact disc read-only memory (CD-ROM), optical storage, etc.
  • These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device that implements the functions specified in one or more processes in the flowchart and/or one or more boxes in the block diagram.
  • These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and/or one or more boxes in the block diagram.

Abstract

一种抑制低频振荡的方法和系统，系统包括：调频控制回路和振荡抑制回路，振荡抑制回路包括振荡判定单元、功能切换开关及功能单元，振荡判定单元设置为根据调频控制回路输出的机组实际功率以及机组侧频率信号来进行低频振荡判定；振荡判定单元设置为：响应于低频振荡未发生，控制功能切换开关连通频差函数F1(x)和F2(x)与调频控制回路，使机组侧频率信号通过频差函数F1(x)和F2(x)后输入至调频控制回路；振荡判定单元设置为：响应于低频振荡发生，根据低频振荡烈度级别控制功能切换开关选择功能单元中的功能；功能单元设置为对通过频差函数F1(x)和F2(x)后的机组侧频率信号进行处理，并将处理后的机组侧频率信号输入至调频控制回路来实现低频振荡抑制。

Description

抑制低频振荡的方法和系统
本申请要求在2022年09月30日提交中国专利局、申请号为202211231928.1的中国专利申请的优先权，该申请的全部内容通过引用结合在本申请中。
技术领域
本申请涉及发电机组频率控制技术领域，例如涉及一种抑制低频振荡的方法和系统。
背景技术
新能源发电大量接入，由于其具有随机性、间歇性和波动性的特点，同时电力系统调峰能力不足，导致网频波动较为频繁。以某一区域电网为例，20xx年8、9、10月份一次调频动作次数(即网频超出死区±2rpm的情况)分别为65次、319次、164次，同比其他月份动作次数增加5-8倍，环比往年相同月份动作次数增加8-10倍。另一方面大量火电机组完成了灵活性改造并运行在深度调峰区间，由于该工况下机组主、辅设备工作区发生改变，机组转动惯量不断减低，抗扰动能力不断减低。外扰或内扰的同时作用造成机组容易触发机组级强迫振荡，特别是电机组低频振荡事故频发，火电机组的支撑性、调节性作用不但没有体现，反而给系统稳定带来了巨大隐患，危及机组及电网运行安全。
电力系统低频振荡(也称为机电振荡、功率振荡)是指：电力系统受到扰动时，并列运行的同步发电机的转子间的相对摇摆，导致系统中出现功率、电压、功角等电气量不同程度振荡的现象。这种持续振荡的频率经常在0.2～2.5Hz之间，因此称为低频振荡。若振荡频率在0.2～0.7Hz之间，称为区间振荡模式。该模式是两个区域间机群的振荡，振荡功率通过联络线向整个系统传播，区间振荡模式危害一般比较大。低频振荡的研究大多集中在励磁系统和电力系统稳定器(Power System Stabilizer，PSS)系统，主要对系统建模、阻尼特性等方面进行分析研究，但是对于火电机组(原动机)侧引发的低频振荡问题，尚无完整的基于分散控制系统(Distributed Control System，DCS)的针对低频振荡问题的在线主动解决方案。
源侧(即原动机侧)低频振荡的问题的产生主要源于如下两个因素：一方面是外部客观因素，由于大量新能源机组的接入电网，其固有的波动特性，导致网频波动频繁；另一方面由于机组系统的工况和调频控制回路参数等问题，调频回路大幅波动导致机组侧稳定性大幅下降，极易发生低频振荡的问题。
相关技术中的机组频率控制采用的典型控制逻辑如图1所示。
图1中，自动发电量控制(Automatic Generation Control，AGC)负荷指令和机组侧频率(即图中所示网频)通过频差函数F1(x)后叠加作为比例-积分-微分(Proportion-Integral-Differential，PID)的设定值(Setpoit，SP)，机组实际功率作为PID的被调量，其PID的控制输出叠加频差函数F2(x)的动作指令作为综合流量指令，作用到汽轮机的阀门控制上。当网频低于49.9667Hz后，频差函数F1(x)和频差函数F2(x)都同时作用到PID的负荷设定值和综合流量指令，使其增大调阀开度，增加了汽轮机进汽量，进而增大汽轮机出力，发电机发出的有功功率增加；反之网频高于50.033Hz后，则减小阀门开度，减少汽轮机进汽量，发电机发出的有功功率减小。机组主动根据源侧的频率变化，改变自身出力大小，主动支撑电网频率的稳定性。
但是上述相关技术中的火电机组的调频控制策略中没有针对频率往复波动导致机组低频振荡的主动防御控制策略。当火电机组由于外部网频大幅反复波动和自身系统原因等导致控制系统稳定性降低，而诱发低频振荡发生时，无法通过源侧驱动端主动干预进行必要的防御，无法防止振荡的进一步放大，从而导致系统的稳定性大幅下降。
发明内容
本申请提供一种抑制低频振荡的方法和系统，解决了源侧低频振荡问题在源侧无法实现自主监控和主动防御的问题，大幅避免了低频振荡的发生。
根据本申请的第一方面，本申请实施例提供了一种抑制低频振荡的系统，该系统包括：调频控制回路和振荡抑制回路，所述调频控制回路和所述振荡抑制回路相连接，所述振荡抑制回路包括振荡判定单元、功能切换开关和功能单元，所述振荡判定单元，设置为根据所述调频控制回路输出的机组实际功率以及机组侧频率信号来进行低频振荡判定；所述振荡判定单元，设置为：响应于所述低频振荡未发生，控制所述功能切换开关连通频差函数F1(x)和F2(x)与所述调频控制回路，使所述机组侧频率信号通过频差函数F1(x)和F2(x)后输入至所述调频控制回路；响应于所述低频振荡发生，根据低频振荡烈度级别控制所述功能切换开关选择所述功能单元中的功能；所述功能单元，设置为对通过所述频差函数F1(x)和F2(x)后的机组侧频率信号进行处理，并将处理后的机组侧频率信号输入至所述调频控制回路来实现低频振荡抑制。
可选的，本实施例上述系统中，所述振荡判定单元还设置为：响应于所述低频振荡发生，根据低频振荡特征量确定所述低频振荡烈度级别，所述特征量包括振荡幅值、振荡周期和振荡持续时间。
可选的，本实施例上述系统中，在负荷的振荡幅值小于5MW，振荡周期大 于1s，持续时间大于10s的情况下，判定所述低频振荡烈度级别为低烈度级别；在负荷的振荡幅值大于5MW且小于8MW，振荡周期小于5s且大于0.2s，持续时间大于10s，判定所述低频振荡烈度级别为中烈度级别；在负荷的振荡幅值大于8MW，振荡周期小于5s且大于0.2s，持续时间大于15s的情况下，判定所述低频振荡烈度级别为高烈度级别。
可选的，本实施例上述系统中，所述振荡判定单元设置为通过如下方式根据所述低频振荡烈度级别控制所述功能切换开关选择所述功能单元中的功能：确定所述低频振荡烈度级别为低烈度级别，控制所述功能切换开关选择所述功能单元中的抑制功能单元；所述抑制功能单元设置为对通过所述频差函数F1(x)和F2(x)的所述机组侧频率信号进行抑制处理后输入至所述调频控制回路，实现调频动作的起始段根据所述频差函数F1(x)和F2(x)的动作值进行动作。
可选的，本实施例上述系统中，所述振荡判定单元设置为通过如下方式根据所述低频振荡烈度级别控制所述功能切换开关选择所述功能单元中的功能：确定所述低频振荡烈度级别为中烈度级别，控制所述功能切换开关选择所述功能单元中的迫降功能单元；所述迫降功能单元设置为对通过所述频差函数F1(x)和F2(x)的所述机组侧频率信号进行迫降处理后输入至所述调频控制回路，实现调频动作幅值根据调频负荷大幅衰减的功能。
可选的，本实施例上述系统中，所述振荡判定单元设置为通过如下方式根据所述低频振荡烈度级别控制所述功能切换开关选择所述功能单元中的功能：确定所述低频振荡烈度级别为高烈度级别，控制所述功能切换开关选择所述功能单元中的阻断功能单元；所述阻断功能单元设置为阻断机组侧频率信号通过所述频差函数F1(x)和F2(x)后输入至所述调频控制回路，实现所述调频控制回路的调频功能的暂时切除功能。
本申请实施例提供了一种抑制低频振荡的方法，该方法包括：根据调频控制回路输出的机组实际功率以及机组侧频率信号来进行低频振荡判定；响应于所述低频振荡未发生，控制功能切换开关连通频差函数F1(x)和F2(x)与所述调频控制回路，使所述机组侧频率信号通过所述频差函数F1(x)和F2(x)后输入至所述调频控制回路；响应于所述低频振荡发生，根据低频振荡烈度级别控制所述功能切换开关选择功能单元中的功能；基于所选功能，对通过所述频差函数F1(x)和F2(x)后的机组侧频率信号进行处理，并将处理后的机组侧频率信号输入至所述调频控制回路来实现低频振荡抑制。
可选的，本实施例中，所述方法还包括：响应于所述低频振荡发生，根据低频振荡特征量确定所述低频振荡烈度级别，所述特征量包括振荡幅值、振荡周期和振荡持续时间。
可选的，本实施例中，在负荷的振荡幅值小于5MW，振荡周期大于1s，持续时间大于10s的情况下，判定所述低频振荡烈度级别为低烈度级别；在负荷的振荡幅值大于5MW且小于8MW，振荡周期小于5s且大于0.2s，持续时间大于10s情况下，判定所述低频振荡烈度级别为中烈度级别；在负荷的振荡幅值大于8MW，振荡周期小于5s且大于0.2s，持续时间大于15s的情况下，判定所述低频振荡烈度级别为高烈度级别。
可选的，本实施例中，所述根据所述低频振荡烈度级别控制所述功能切换开关选择功能单元中的功能包括：确定所述低频振荡烈度级别为低烈度级别，控制所述功能切换开关选择所述功能单元中的抑制功能单元，所述抑制功能单元对通过所述频差函数F1(x)和F2(x)的所述机组侧频率信号进行抑制处理后输入至所述调频控制回路，实现调频动作的起始段根据所述频差函数F1(x)和F2(x)的动作值进行动作。
可选的，本实施例中，所述根据所述低频振荡烈度级别控制所述功能切换开关选择功能单元中的功能包括：确定所述低频振荡烈度级别为中烈度级别，控制所述功能切换开关选择所述功能单元中的迫降功能单元，所述迫降功能单元对通过所述频差函数F1(x)和F2(x)的所述机组侧频率信号进行迫降处理后输入至所述调频控制回路，实现调频动作幅值根据调频负荷大幅衰减的功能。
可选的，本实施例中，所述根据所述低频振荡烈度级别控制所述功能切换开关选择功能单元中的功能包括：确定所述低频振荡烈度级别为高烈度级别，控制所述功能切换开关选择所述功能单元中的阻断功能单元，所述阻断功能单元阻断所述机组侧频率信号通过所述频差函数F1(x)和F2(x)后输入至所述调频控制回路，实现所述调频控制回路的调频功能的暂时切除功能。
本申请实施例还提供了一种电子设备，包括存储器、处理器以及存储在所述存储器上并可在所述处理器上运行的计算机程序，所述处理器执行所述计算机程序时实现上述实施例的方法。
本申请实施例还提供一种计算机可读存储介质，其上存储有计算机程序，所述计算机程序被处理器执行时实现上述实施例的方法。
本申请实施例还提供一种计算机程序产品，包括计算机程序/指令，所述计算机程序/指令被处理器执行时实现上述实施例的方法。
附图说明
下面将对实施例或相关技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术 人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。在附图中：
图1是现有的机组频率控制的典型控制逻辑图；
图2是本申请实施例提供的一种抑制低频振荡的系统结构示意图；
图3是机组低频振荡与触发抑制功能后的对比曲线图；
图4是机组低频振荡与触发迫降功能后的对比曲线图；
图5是机组低频振荡与触发阻断功能后的对比曲线图；
图6是本申请实施例提供的一种抑制低频振荡的方法的流程示意图；
图7是本申请另一实施例提供的一种抑制低频振荡的方法的流程示意图；
图8是本申请实施例提供的一种电子设备的结构示意图。
具体实施方式
下面结合附图对本申请实施例进行说明。在此，本申请的示意性实施例及其说明用于解释本申请，但并不作为对本申请的限定。
如图2所示为本申请实施例提供的一种抑制低频振荡的系统结构示意图，该系统包括：调频控制回路100和振荡抑制回路400，调频控制回路100和振荡抑制回路400相连接，由图2可见，本申请的振荡抑制回路400包括振荡判定单元200、功能切换开关S1和S2以及功能单元300。
调频控制回路100和图1中的调频控制回路相同，所不同的是调控控制回路100中两求和单元的网频输入经过了振荡抑制回路400的控制。
振荡判定单元200设置为根据所述调频控制回路100输出的机组实际功率以及机组侧频率信号(即图2中的网频)来进行低频振荡判定，即判定是否发生低频振荡。
当振荡判定单元200判定未发生低频振荡的时候，该振荡判定单元200会控制功能切换开关S1和S2，使机组侧频率信号通过频差函数F1(x)和F2(x)后作用于调频控制回路100，表示在图2中，功能切换开关S1和S2可以切换至1侧，即可以使调频控制回路100以原有工作方式运作。
当振荡判定单元200判定发生低频振荡的时候，该振荡判定单元200会根据低频振荡烈度级别控制功能切换开关S1和S2选择功能单元300中的对应功能，对通过频差函数F1(x)和F2(x)后的机组侧频率信号进行相应处理后作用于调频控制回路100来实现低频振荡抑制。
可选的，作为本申请的一个实施例，振荡判定单元200在判定发生了低频振荡的时候，还可以继续根据低频振荡特征量来确定低频振荡烈度级别，该特征量可以包括振荡幅值、振荡周期和振荡持续时间。
可选的，上述低频振荡烈度级别可以包括低、中、高三级，当负荷的振荡幅值小于5MW，振荡周期大于1s，持续时间大于10s时，振荡判定单元200判定低频振荡烈度级别为低烈度级别；当负荷的振荡幅值大于5MW且小于8MW，振荡周期小于5s且大于0.2s，持续时间大于10s时，振荡判定单元200判定低频振荡烈度级别为中烈度级别(危险级别)；当负荷的振荡幅值大于8MW，振荡周期小于5s且大于0.2s，持续时间大于15s时，振荡判定单元200判定低频振荡烈度级别为高烈度级别(极度危险级别)。
可选的，当振荡判定单元200判定发生的低频振荡为低烈度级别时，振荡判定单元200会控制功能切换开关S1和S2使其都切换至2侧，即使其都切换至功能单元300中的抑制功能单元上，该抑制功能单元会对通过频差函数F1(x)和F2(x)的机组侧频率信号进行处理后作用于所述调频控制回路100，从而实现调频控制回路100的调频动作的起始段根据所述频差函数F1(x)和F2(x)的动作值进行动作。
例如某厂F1(x)设置如下表1
表1
当判定为安全等级时，假设现在的转差为-4rpm(0.0667Hz)，产生抑制动作过程初期将负荷(动作值)直接设定为-15.7769MW，当后期转差为-2rpm时，负荷设定值变为0。同样对于F2(x)也存在类似动作。
可选的，当振荡判定单元200判定发生的低频振荡为中烈度级别时，振荡判定单元200会控制功能切换开关S1和S2使其都切换至3侧，即使其都切换至功能单元300中的迫降功能单元上，该迫降功能单元会对通过频差函数F1(x)和F2(x)的机组侧频率信号进行处理后作用于所述调频控制回路100，从而实现调频动作幅值根据调频负荷大幅衰减的功能。
当判定为危险级别时，假设现在的转差为-4rpm(0.0667Hz)，产生迫降动作过程的初期将负荷直接设定为-15.7769×系数(系数远远小于1)，动作幅值大幅降低。同样对于F2(x)也存在类似动作。
可选的，当振荡判定单元200判定发生的低频振荡为高烈度级别时，振荡 判定单元200会控制功能切换开关S1和S2使其都切换至4侧，即使其都切换至功能单元300中的阻断功能单元上，该阻断功能单元会阻断机组侧频率信号通过频差函数F1(x)和F2(x)后输入至所述调频控制回路100，调频控制回路100的调频功能会被暂时阻断。
下面通过几个实施例来对本申请技术方案进行说明，以一350MW超临界机组出现低频振荡现象为例，图3是机组低频振荡与触发抑制功能后的对比曲线图，图4是机组低频振荡与触发迫降功能后的对比曲线图，图5是机组低频振荡与触发阻断功能后的对比曲线图。
由图3可见，机组在无低频振荡抑制功能时振荡幅值达到212.2MW-208.8MW，振荡最大值与最小值之间差3.4MW。触发低频振荡抑制功能后，振荡负荷急速下降为210MW-211MW之间，振荡最大值与最小值之间的差值仅有不到1MW，并且没有出现周期性波动现象。
由图4可见，机组在无低频振荡迫降功能时振荡幅值达到214.6MW-207.9MW，振荡最大值与最小值之间6.7MW。触发低频振荡迫降功能后，振荡负荷急速下降为209.5MW-210.5MW之间，振荡最大值与最小值之间仅有不到1MW，并且没有出现周期性波动现象。
由图5可见，机组在无低频振荡阻断功能时振荡幅值达到213.8MW-203.9MW，振荡最大值与最小值之间9.9MW。触发低频振荡阻断功能后，振荡负荷急速下降为209MW-211MW之间，振荡最大值与最小值之间仅有不到2MW，并且没有出现周期性波动现象。
综上所述，本申请实施例提供的抑制低频振荡的系统，解决了源侧低频振荡问题在源侧无法实现自主监控和主动防御的问题，大幅避免了低频振荡的事故的发生。同时，采用本申请的三级抑制方式，能有效地避免低频振荡误判定导致的调频性能下降的问题，不会发生只要判定低级振荡就要切除调频控制回路的情况，即本申请的三级抑制方式对于机组调频安全与性能提升具有重要意义。
如图6所示为本申请实施例提供的一种抑制低频振荡的方法的流程示意图，该方法包括如下步骤，
步骤S601：根据调频控制回路输出的机组实际功率以及机组侧频率信号来进行低频振荡判定，若未发生低频振荡，则进入步骤S602，否则进入步骤S603。
步骤S602：控制功能切换开关连通频差函数F1(x)和F2(x)与调频控制回路，使所述机组侧频率信号通过频差函数F1(x)和F2(x)后输入至所述调频控制回路。
步骤S603：根据低频振荡烈度级别控制所述功能切换开关选择功能单元中 的功能。
步骤S604：基于所选功能，对通过频差函数F1(x)和F2(x)后的机组侧频率信号进行处理，并将处理后的机组侧频率信号输入至所述调频控制回路来实现低频振荡抑制。
由上述可知，本申请实施例提供的抑制低频振荡的方法，解决了源侧低频振荡问题在源侧无法实现自主监控和主动防御的问题，大幅避免了低频振荡的事故的发生。同时又能有效地避免低频振荡误判定导致的调频性能下降的问题，对于机组调频安全与性能提升具有重要意义。
如图7所示为本申请另一实施例提供的一种抑制低频振荡的方法的流程示意图，该方法包括如下步骤。
步骤S701：根据调频控制回路输出的机组实际功率以及机组侧频率信号来进行低频振荡判定，若未发生低频振荡，则进入步骤S702，否则进入步骤S703。
步骤S702：控制功能切换开关连通频差函数F1(x)和F2(x)与调频控制回路，使所述机组侧频率信号通过频差函数F1(x)和F2(x)后输入至所述调频控制回路。
步骤S703：响应于低频振荡发生，根据低频振荡特征量确定低频振荡烈度级别，所述特征量包括振荡幅值、振荡周期和振荡持续时间。若低频振荡为低烈度级别，则进入步骤S704，若低频振荡为中烈度级别，则进入步骤S705，若低频振荡为高烈度级别，则进入步骤S706。
当负荷的振荡幅值小于5MW，振荡周期大于1s，持续时间大于10s时，判定低频振荡烈度级别为低烈度级别；当负荷的振荡幅值大于5MW且小于8MW，振荡周期小于5s且大于0.2s，持续时间大于10s时，判定低频振荡烈度级别为中烈度级别；当负荷的振荡幅值大于8MW，振荡周期小于5s且大于0.2s，持续时间大于15s时，判定低频振荡烈度级别为高烈度级别。
步骤S704：确定低频振荡烈度级别为低烈度级别，控制功能切换开关选择功能单元中的抑制功能单元，所述抑制功能单元对通过频差函数F1(x)和F2(x)的机组侧频率信号进行抑制处理后输入至所述调频控制回路，实现调频动作的起始段根据所述频差函数F1(x)和F2(x)的动作值进行动作。
步骤S705：确定低频振荡烈度级别为中烈度级别，控制功能切换开关选择功能单元中的迫降功能单元，所述迫降功能单元对通过频差函数F1(x)和F2(x)的机组侧频率信号进行迫降处理后输入至所述调频控制回路，实现调频动作幅值根据调频负荷大幅衰减的功能。
步骤S706：确定所述低频振荡烈度级别为高烈度级别，控制功能切换开关选择功能单元中的阻断功能单元，所述阻断功能单元阻断机组侧频率信号通过 频差函数F1(x)和F2(x)后输入至所述调频控制回路，调频控制回路的调频功能会被暂时阻断。
综上所述，本申请实施例提供的抑制低频振荡的方法，解决了源侧低频振荡问题在源侧无法实现自主监控和主动防御的问题，大幅避免了低频振荡的事故的发生。同时又能有效地避免低频振荡误判定导致的调频性能下降的问题，对于机组调频安全与性能提升具有重要意义。
图8是本申请实施例提供的电子设备的示意图。图8所示的电子设备为通用数据处理装置，其包括通用的计算机硬件结构，其至少包括处理器801和存储器802。处理器801和存储器802通过总线803连接。存储器802适于存储处理器801可执行的一条或多条指令或程序。该一条或多条指令或程序被处理器801执行以实现上述抑制低频振荡的方法中的步骤。
上述处理器801可以是独立的微处理器，也可以是一个或者多个微处理器集合。由此，处理器801通过执行存储器802所存储的命令，从而执行如上所述的本申请实施例的方法流程实现对于数据的处理和对于其他装置的控制。总线803将上述多个组件连接在一起，同时将上述组件连接到显示控制器804和显示装置以及输入/输出(Input/Output，I/O)装置805。I/O装置805可以是鼠标、键盘、调制解调器、网络接口、触控输入装置、体感输入装置、打印机以及本领域公知的其他装置。典型地，I/O装置805通过I/O控制器806与系统相连。
存储器802可以存储软件组件，例如操作系统、通信模块、交互模块以及应用程序。以上所述的每个模块和应用程序都对应于完成一个或多个功能和在申请实施例中描述的方法的一组可执行程序指令。
本申请实施例还提供一种计算机可读存储介质，其上存储有计算机程序，该计算机程序被处理器执行时以实现上述抑制低频振荡的方法的步骤。
本申请实施例还提供一种计算机程序产品，包括计算机程序/指令，该计算机程序/指令被处理器执行时实现上述抑制低频振荡的方法的步骤。
综上所述，本申请所提出的抑制低频振荡的方法和装置，解决了源侧低频振荡问题在源侧无法实现自主监控和主动防御的问题，大幅避免了低频振荡的事故的发生。同时又能有效地避免低频振荡误判定导致的调频性能下降的问题，对于机组调频安全与性能提升具有重要意义。
本领域内的技术人员应明白，本申请的实施例可提供为方法、系统、或计算机程序产品。因此，本申请可采用完全硬件实施例、完全软件实施例、或结合软件和硬件方面的实施例的形式。而且，本申请可采用在一个或多个其中包 含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、便携式紧凑盘只读存储器(Compact Disc Read-Only Memory，CD-ROM)、光学存储器等)上实施的计算机程序产品的形式。
本申请是参照根据本申请实施例的方法、设备(系统)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每一流程和/或方框、以及流程图和/或方框图中的流程和/或方框的结合。可提供这些计算机程序指令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器，使得通过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。
这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方式工作的计算机可读存储器中，使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品，该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。
这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上，使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。

Claims (15)

  1. 一种抑制低频振荡的系统，包括：调频控制回路和振荡抑制回路，所述调频控制回路和所述振荡抑制回路相连接，所述振荡抑制回路包括振荡判定单元、功能切换开关和功能单元，
    所述振荡判定单元，设置为根据所述调频控制回路输出的机组实际功率以及机组侧频率信号来进行低频振荡判定；
    所述振荡判定单元，设置为：响应于所述低频振荡未发生，控制所述功能切换开关连通频差函数F1(x)和F2(x)与所述调频控制回路，使所述机组侧频率信号通过所述频差函数F1(x)和F2(x)后输入至所述调频控制回路；响应于所述低频振荡发生，根据低频振荡烈度级别控制所述功能切换开关选择所述功能单元中的功能；
    所述功能单元，设置为基于所选功能，对通过所述频差函数F1(x)和F2(x)后的机组侧频率信号进行处理，并将处理后的机组侧频率信号输入至所述调频控制回路来实现低频振荡抑制。
  2. 如权利要求1所述的系统，其中，所述振荡判定单元还设置为：响应于所述低频振荡发生，根据低频振荡特征量确定所述低频振荡烈度级别，所述低频振荡特征量包括振荡幅值、振荡周期和振荡持续时间。
  3. 如权利要求2所述的系统，其中，在负荷的振荡幅值小于5MW，振荡周期大于1s，持续时间大于10s的情况下，判定所述低频振荡烈度级别为低烈度级别；在负荷的振荡幅值大于5MW且小于8MW，振荡周期小于5s且大于0.2s，持续时间大于10s的情况下，判定所述低频振荡烈度级别为中烈度级别；在负荷的振荡幅值大于8MW，振荡周期小于5s且大于0.2s，持续时间大于15s的情况下，判定所述低频振荡烈度级别为高烈度级别。
  4. 如权利要求3所述的系统，其中，
    所述振荡判定单元设置为通过如下方式根据所述低频振荡烈度级别控制所述功能切换开关选择所述功能单元中的功能：
    确定所述低频振荡烈度级别为低烈度级别，控制所述功能切换开关选择所述功能单元中的抑制功能单元；
    所述抑制功能单元设置为对通过所述频差函数F1(x)和F2(x)的所述机组侧频率信号进行抑制处理后输入至所述调频控制回路，实现调频动作的起始段根据所述频差函数F1(x)和F2(x)的动作值进行动作。
  5. 如权利要求3所述的系统，其中，
    所述振荡判定单元设置为通过如下方式根据所述低频振荡烈度级别控制所 述功能切换开关选择所述功能单元中的功能：
    确定所述低频振荡烈度级别为中烈度级别，控制所述功能切换开关选择所述功能单元中的迫降功能单元；
    所述迫降功能单元设置为对通过所述频差函数F1(x)和F2(x)的所述机组侧频率信号进行迫降处理后输入至所述调频控制回路，实现调频动作幅值根据调频负荷大幅衰减的功能。
  6. 如权利要求3所述的系统，其中，
    所述振荡判定单元设置为通过如下方式根据所述低频振荡烈度级别控制所述功能切换开关选择所述功能单元中的功能：
    确定所述低频振荡烈度级别为高烈度级别，控制所述功能切换开关选择所述功能单元中的阻断功能单元；
    所述阻断功能单元设置为阻断所述机组侧频率信号通过所述频差函数F1(x)和F2(x)后输入至所述调频控制回路，所述调频控制回路的调频功能会被暂时阻断。
  7. 一种抑制低频振荡的方法，包括：
    根据调频控制回路输出的机组实际功率以及机组侧频率信号来进行低频振荡判定；
    响应于所述低频振荡未发生，控制功能切换开关连通频差函数F1(x)和F2(x)与所述调频控制回路，使所述机组侧频率信号通过所述频差函数F1(x)和F2(x)后输入至所述调频控制回路；
    响应于所述低频振荡发生，根据低频振荡烈度级别控制所述功能切换开关选择功能单元中的功能；
    基于所选功能，对通过所述频差函数F1(x)和F2(x)后的机组侧频率信号进行处理，并将处理后的机组侧频率信号输入至所述调频控制回路来实现低频振荡抑制。
  8. 如权利要求7所述的方法，还包括：响应于所述低频振荡发生，根据低频振荡特征量确定所述低频振荡烈度级别，所述低频振荡特征量包括振荡幅值、振荡周期和振荡持续时间。
  9. 如权利要求8所述的方法，其中，在负荷的振荡幅值小于5MW，振荡周期大于1s，持续时间大于10s的情况下，判定所述低频振荡烈度级别为低烈度级别；在负荷的振荡幅值大于5MW且小于8MW，振荡周期小于5s且大于0.2s，持续时间大于10s的情况下，判定所述低频振荡烈度级别为中烈度级别； 在负荷的振荡幅值大于8MW，振荡周期小于5s且大于0.2s，持续时间大于15s的情况下，判定所述低频振荡烈度级别为高烈度级别。
  10. 如权利要求9所述的方法，其中，所述根据所述低频振荡烈度级别控制所述功能切换开关选择功能单元中的功能包括：
    确定所述低频振荡烈度级别为低烈度级别，控制所述功能切换开关选择所述功能单元中的抑制功能单元，所述抑制功能单元对通过所述频差函数F1(x)和F2(x)的所述机组侧频率信号进行抑制处理后输入至所述调频控制回路，实现调频动作的起始段根据所述频差函数F1(x)和F2(x)的动作值进行动作。
  11. 如权利要求9所述的方法，其中，所述根据所述低频振荡烈度级别控制所述功能切换开关选择功能单元中的功能包括：
    确定所述低频振荡烈度级别为中烈度级别，控制所述功能切换开关选择所述功能单元中的迫降功能单元，所述迫降功能单元对通过所述频差函数F1(x)和F2(x)的所述机组侧频率信号进行迫降处理后输入至所述调频控制回路，实现调频动作幅值根据调频负荷大幅衰减的功能。
  12. 如权利要求9所述的方法，其中，所述根据所述低频振荡烈度级别控制所述功能切换开关选择功能单元中的功能包括：
    确定所述低频振荡烈度级别为高烈度级别，控制所述功能切换开关选择所述功能单元中的阻断功能单元，所述阻断功能单元阻断所述机组侧频率信号通过所述频差函数F1(x)和F2(x)后输入至所述调频控制回路，所述调频控制回路的调频功能会被暂时阻断。
  13. 一种电子设备，包括存储器、处理器以及存储在所述存储器上并可在所述处理器上运行的计算机程序，其中，所述处理器执行所述计算机程序时实现权利要求7至12任一项所述方法。
  14. 一种计算机可读存储介质，其上存储有计算机程序，其中，所述计算机程序被处理器执行时实现权利要求7至12任一项所述方法。
  15. 一种计算机程序产品，包括计算机程序/指令，其中，所述计算机程序/指令被处理器执行时实现权利要求7至12任一项所述方法。
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