WO2024260474A1 - 电网系统的安全惯量确定方法、装置和计算机设备 - Google Patents

电网系统的安全惯量确定方法、装置和计算机设备 Download PDF

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Publication number
WO2024260474A1
WO2024260474A1 PCT/CN2024/110141 CN2024110141W WO2024260474A1 WO 2024260474 A1 WO2024260474 A1 WO 2024260474A1 CN 2024110141 W CN2024110141 W CN 2024110141W WO 2024260474 A1 WO2024260474 A1 WO 2024260474A1
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WIPO (PCT)
Prior art keywords
power grid
inertia
grid system
frequency
power
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Ceased
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PCT/CN2024/110141
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English (en)
French (fr)
Inventor
王海云
于希娟
张再驰
陈茜
杨莉萍
张雨璇
汪伟
姚艺迪
徐鹏
王方雨
郑凯元
王程
毕天姝
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North China Electric Power University
State Grid Beijing Electric Power Co Ltd
State Grid Corp of China SGCC
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North China Electric Power University
State Grid Beijing Electric Power Co Ltd
State Grid Corp of China SGCC
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Publication of WO2024260474A1 publication Critical patent/WO2024260474A1/zh
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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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
    • H02J3/001—Arrangements for handling faults or abnormalities, e.g. emergencies or contingencies
    • H02J3/0014—Arrangements for handling faults or abnormalities, e.g. emergencies or contingencies for preventing or reducing power oscillations in networks
    • H02J3/00142—Oscillations concerning frequency
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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
    • H02J3/38—Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel
    • H02J3/46—Controlling the sharing of generated power between the generators, sources or networks
    • H02J3/48—Controlling the sharing of active power

Definitions

  • the present application relates to the field of power system control, for example, to a method, device and computer equipment for determining the safety inertia of a power grid system.
  • a large number of new energy generating units are connected to the power grid by using power electronic devices, so that the transmission power of the new energy units is decoupled from the grid frequency.
  • active disturbance occurs in the conventional control mode, it cannot provide inertia support for the grid. This causes the inertia level of the system to decrease when the growth rate of the new energy units is higher than that of the conventional synchronous units or when the new energy units replace the synchronous units.
  • the inertia can not only delay the rapid change of the system frequency, win action time for the system's primary frequency regulation, but also optimize the system frequency response so that the lowest point of the system frequency after the disturbance does not exceed the limit.
  • the embodiments of the present application provide a method, an apparatus and a computer device for determining the safe inertia of a power grid system, so as to at least solve the technical problem of low accuracy of the method for determining the minimum safe inertia of a power grid system in the related art.
  • a method for determining a safe inertia of a power grid system including: determining a first safety inertia for ensuring safe operation of the power grid system when a frequency change rate exceeds a first threshold after a disturbance occurs in the power grid system; determining a second safety inertia for ensuring safe operation of the power grid system when a frequency is lower than a second threshold after a disturbance occurs in the power grid system; and determining a target safety inertia based on the first safety inertia and the second safety inertia, wherein the target safety inertia is a lower limit value of the safety inertia for ensuring safe operation of the power grid system.
  • determining a first safety inertia for ensuring safe operation of a power grid system when a frequency change rate exceeds a first threshold after a disturbance occurs in the power grid system includes: obtaining a rated frequency of the power grid system; determining a frequency change rate near a disturbance point of the power grid system; determining an amount of change in load power caused by the frequency change; and determining the first safety inertia based on the rated frequency, the frequency change rate near the disturbance point, and the amount of change in load power caused by the frequency change.
  • determining the frequency change rate of a near disturbance point of a power grid system includes: obtaining the frequency change rate of an inertia center of the power grid system; determining a proportional relationship between the frequency change rate of a near disturbance point and the frequency change rate of the inertia center; and determining the frequency change rate of a near disturbance point based on the proportional relationship and the frequency change rate of the inertia center.
  • determining the change in load power due to frequency change includes: obtaining the active power of the load in the power grid system and the voltage of the load node before the disturbance occurs; determining a first power change based on the active power of the load and the voltage of the load node, wherein the first power change is the change in load power due to voltage change; determining the power change exceeding a third threshold generated by the power grid system under the influence of the disturbance as a second power change; and determining the change in load power due to frequency change as the difference between the first power change and the second power change.
  • determining a second safety inertia that ensures safe operation of the power grid system when the frequency is lower than a second threshold after a disturbance occurs in the power grid system includes: obtaining a rated lower limit frequency of the power grid system; in response to the frequency being the rated lower limit frequency after a disturbance occurs in the power grid system, determining that the inertia that ensures safe operation of the power grid system is the second safety inertia.
  • determining the inertia for ensuring safe operation of the power grid system to be the second safety inertia includes: acquiring the rated frequency of the power grid system, the damping coefficient of the power grid system, the primary frequency modulation rate of the power grid system under the disturbance, and the primary frequency modulation action time; in response to the frequency of the power grid system being the rated lower limit frequency after a disturbance occurs, determining the inertia for ensuring safe operation of the power grid system to be the second safety inertia according to the rated frequency of the power grid system, the damping coefficient of the power grid system, the primary frequency modulation rate of the power grid system under the disturbance, and the primary frequency modulation action time.
  • determining the target safety inertia according to the first safety inertia and the second safety inertia includes: determining the maximum value of the first safety inertia and the second safety inertia as the target safety inertia.
  • a safety inertia determination device for a power grid system, including: a first determination module, configured to determine a first safety inertia for ensuring safe operation of the power grid system when the frequency change rate exceeds a first threshold after a disturbance occurs in the power grid system; a second determination module, configured to determine a second safety inertia for ensuring safe operation of the power grid system when the frequency is lower than a second threshold after a disturbance occurs in the power grid system; and a third determination module, configured to determine a target safety inertia based on the first safety inertia and the second safety inertia, wherein the target safety inertia is a lower limit value of the safety inertia for ensuring safe operation of the power grid system.
  • a non-volatile storage medium including a stored program, wherein when the program is running, the device where the non-volatile storage medium is located is controlled to execute any one of the above-mentioned methods for determining the safety inertia of the power grid system.
  • a computer device includes a processor, and the processor is used to run a program.
  • the program is run, any one of the above-mentioned methods for determining the safe inertia of the power grid system is executed.
  • FIG1 shows a hardware structure block diagram of a computer terminal for implementing a method for determining a safe inertia of a power grid system
  • FIG2 shows a schematic diagram of a frequency domain response process of a power grid system
  • FIG. 3 is a schematic diagram of a flow chart of a method for determining a safe inertia of a power grid system according to an embodiment of the present application
  • FIG4 is a schematic diagram of a load voltage characteristic power response according to an embodiment of the present application.
  • FIG5 is a schematic diagram of a frequency response curve after linearization processing provided in an embodiment of the present application.
  • FIG6 is a structural block diagram of a device for determining safety inertia of a power grid system provided according to an embodiment of the present application.
  • an embodiment of a method for determining a safe inertia of a power grid system is provided.
  • the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.
  • the computer terminal 10 may include one or more (102a, 102b, ..., 102n are used to illustrate) processors (the processor may include a processing device such as a microprocessor MCU or a programmable logic device FPGA), and a memory 104 for storing data.
  • the computer terminal 10 may also include: a display, an input/output interface (I/O interface), a universal serial bus (USB) port (which may be included as one of the ports of the BUS bus), a network interface, a power supply and/or a camera.
  • I/O interface input/output interface
  • USB universal serial bus
  • FIG1 is for illustration.
  • the computer terminal 10 may also include more or fewer components than those shown in FIG1 , or have a configuration different from that shown in FIG1 .
  • the one or more processors and/or other data processing circuits described above may generally be referred to herein as "data processing circuits".
  • the data processing circuits may be embodied in whole or in part as software, hardware, firmware, or any other combination thereof.
  • the data processing circuit may be a single independent processing module, or may be incorporated in whole or in part into any of the other components in the computer terminal 10.
  • the data processing circuit acts as a processor control (e.g., selection of a variable resistor terminal path connected to an interface).
  • the memory 104 can be used to store software programs and modules of application software, such as the program instructions/data storage device corresponding to the method for determining the safety inertia of the power grid system in the embodiment of the present application.
  • the processor executes various functional applications and data processing by running the software programs and modules stored in the memory 104, that is, the method for determining the safety inertia of the power grid system of the above-mentioned application program is realized.
  • the memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory.
  • the memory 104 may include a memory remotely arranged relative to the processor, and these remote memories may be connected to the computer terminal 10 via a network.
  • Examples of the above-mentioned network include the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof.
  • the display may be, for example, a touch screen liquid crystal display (LCD), which enables a user to interact with a user interface of the computer terminal 10.
  • LCD liquid crystal display
  • FIG. 2 shows a schematic diagram of the frequency domain response process of a power grid system. As shown in Figure 2, the frequency response process of the system can be divided into the following stages.
  • Phase 1 At the moment t1 when the disturbance occurs, there are two processes. One is the redistribution of the disturbance power. This process is actually that each generator group distributes the disturbance power according to the synchronous power coefficient, as shown in formula (1). The meaning is that when the active disturbance ⁇ P occurs at the load k in the system, that is, when the power imbalance generated by the system after the disturbance is ⁇ P, the output electromagnetic power Pei of the i-th generator becomes the superposition value of the original power and the disturbance power. The second process is that the load voltage characteristics affect the operation of the power grid system. It plays a role similar to inertia in the system frequency response by changing the unbalanced power of the system after the disturbance.
  • E i and E j represent the transient potential of the i-th and j-th generators respectively
  • U k is the voltage value across load k
  • G ii is the diagonal element in the system node admittance matrix Y, that is, the self-admittance at node i
  • B ij is the mutual admittance between node i and node j
  • B ik is the mutual admittance between node i and node k
  • G ij is the mutual conductance between node i and node j
  • G ik is the mutual conductance between node i and node k.
  • ⁇ ij ⁇ i - ⁇ j
  • ⁇ i the phase angle difference between the excitation potential and the terminal voltage of the i-th generator in the system, that is, the power angle.
  • ⁇ j the phase angle difference between the excitation potential and the terminal voltage of the j-th generator in the system
  • ⁇ ij the power angle difference between the i-th generator and the j-th generator in the system.
  • ⁇ ik ⁇ i - ⁇ k
  • ⁇ k represents the phase angle difference of load k in the system
  • ⁇ ik represents the power angle difference between the i-th generator and load k in the system.
  • Phase 2 Inertia response phase, from t1 to t2 , after the disturbance occurs, the electromagnetic power of the synchronous generator increases suddenly, while the mechanical power remains unchanged, and the frequency is still in the dead zone of the speed regulator and has not yet taken action. At this time, since the rotor of the synchronous unit stores kinetic energy during the rotation process, it has a certain rotational inertia. After the power imbalance occurs, the rotor of the synchronous generator converts the kinetic energy stored in it into electromagnetic power through the power angle characteristics by accelerating or decelerating, and continues to maintain the active power supply and demand balance of the system.
  • fn is the rated frequency of the power grid
  • Hi is the inertia time constant of the i-th synchronous unit
  • Si is the rated capacity of the i-th synchronous machine
  • f(t) is the function of the frequency change in the power grid with respect to time
  • ⁇ Pi is the deviation between the mechanical power and the electromagnetic power of the synchronous generator, and is the disturbance power borne by the generator at the moment of disturbance.
  • Phase 3 At this time, the inertia response and the primary frequency modulation response in the system work together.
  • the frequency deviation of the system exceeds the frequency modulation dead zone of the speed regulator.
  • the valve opening of the prime mover increases, increasing the mechanical power output to the system, reducing the unbalanced power, and the system inertia support power gradually decreases.
  • the unbalanced power of the system drops to zero, the system frequency reaches the lowest point.
  • Phase 4 After the frequency reaches the lowest point, the unit continues to increase power, making the system's mechanical power greater than the electromagnetic power.
  • the synchronous generator rotor begins to absorb energy and recover part of the speed. At this time, the system's inertia response changes from positive to negative.
  • the system frequency reaches a new balance at t3 and remains at a low level. The system's mechanical power no longer increases.
  • Phase 5 After t 3 , it is the secondary frequency modulation response phase. Since the primary frequency modulation is differential frequency modulation, when the steady-state frequency deviation is large, the secondary frequency modulation needs to be started to increase the active output in the frequency modulation plant and adjust the frequency to the rated value of the system frequency.
  • the speed regulator Since the speed regulator has a frequency insensitive zone and response delay, when an active disturbance occurs, the synchronous machine cannot immediately inject power into the system to eliminate the unbalanced power. Therefore, before the speed regulator is activated, the supply and demand balance can only be maintained by inertia. Inertia can be regarded as energy storage in the generator rotor. In the absence of additional power injection into the system, after an active disturbance occurs, the system frequency will continue to drop to zero at a constant rate by adjusting the inertia alone.
  • inertia plays an important role in maintaining the balance of active power supply and demand, providing an energy source for electromagnetic power, thereby maintaining the balance of active power supply and demand, and slowing down the rate of change of system frequency, buying time for the effect of primary frequency modulation, and is an indispensable part of maintaining system frequency stability. Therefore, this application will solve the minimum safe inertia that meets the requirements of stable operation of the system.
  • FIG3 is a flow chart of a method for determining a safe inertia of a power grid system according to an embodiment of the present application. As shown in FIG3 , the method includes the following steps:
  • Step S302 determining a first safety inertia for ensuring safe operation of the power grid system when a frequency change rate exceeds a first threshold after a disturbance occurs in the power grid system.
  • the frequency change rate can be selected as a characteristic index for constraint, and the first safety inertia that can ensure the safe operation of the power grid system when the frequency change rate of the power grid system exceeds the first threshold under the influence of the disturbance is calculated.
  • the frequency change rate is the largest at the initial moment of the disturbance, and the safety inertia required when the frequency change rate of the power grid system is the largest can be calculated as the first safety inertia.
  • Step S304 determining a second safety inertia for ensuring safe operation of the power grid system when the frequency is lower than a second threshold after a disturbance occurs in the power grid system.
  • the frequency can be selected as a characteristic index for constraint, and the second safety inertia that can ensure the safe operation of the power grid system when the frequency of the power grid system is lower than the second threshold value under the influence of the disturbance is calculated.
  • the frequency corresponding to the first time the frequency change rate drops to 0 is the extreme value of the frequency.
  • the system frequency reaches the lowest value, and the safety inertia required when the power grid system frequency is the lowest can be calculated as the second safety inertia.
  • Step S306 determining a target safety inertia according to the first safety inertia and the second safety inertia, wherein the target safety inertia is a lower limit value of the safety inertia to ensure safe operation of the power grid system.
  • the safety inertia required by the power grid system under the conditions of maximum frequency change rate and minimum frequency can be comprehensively considered, and the minimum safety inertia for safe operation of the power grid system, that is, the lower limit of the safety inertia, can be finally determined.
  • the minimum safety inertia for ensuring the safe operation of the power grid system in the process after the power grid is disturbed is determined, and the minimum safety inertia required by the power grid in various situations is considered, and the minimum safety inertia for ensuring the safe operation of the power grid system in the process after the power grid is disturbed is comprehensively determined, thereby achieving the technical effect of improving the accuracy of determining the minimum safety inertia of the power grid system, and further solving the technical problem of low accuracy of the method for determining the minimum safety inertia of the power grid system in the related technology.
  • determining a first safety inertia for ensuring safe operation of a power grid system when a frequency change rate exceeds a first threshold after a disturbance occurs in the power grid system includes: obtaining a rated frequency of the power grid system; determining a frequency change rate near a disturbance point of the power grid system; determining an amount of change in load power caused by the frequency change; and determining the first safety inertia based on the rated frequency, the frequency change rate near the disturbance point, and the amount of change in load power caused by the frequency change.
  • determining the frequency change rate of a near disturbance point of a power grid system includes: obtaining the frequency change rate of an inertia center of the power grid system; determining a proportional relationship between the frequency change rate of a near disturbance point and the frequency change rate of the inertia center; and determining the frequency change rate of a near disturbance point based on the proportional relationship and the frequency change rate of the inertia center.
  • the frequency change rate of the system is the largest at the moment when the disturbance occurs. If the frequency change rate after the disturbance is constrained not to exceed a threshold value, the frequency change rate at the moment of the disturbance should be used as a reference. At this time, there is no frequency deviation, that is, there is no generator speed regulator and load frequency regulation effect. From formula (3), the minimum safe inertia H min of the system based on the frequency change rate constraint is:
  • ⁇ P max is the maximum disturbance power that may occur in the system, which is generally the disturbance power that occurs when the AC tie line is disconnected, the DC is locked, or the largest generator set in the system stops running.
  • RoCoF max represents the limit value of the frequency change rate of the center of inertia allowed by the system.
  • RoCoF max represents the frequency change rate of the system inertia center, while the frequency constraint is usually based on the system maximum bus frequency or specific bus frequency, which is generally located near the disturbance point.
  • the frequency time-space distribution characteristics are not obvious, and the frequency change rate near the disturbance point is approximately equal to the frequency change rate of the inertia center; but for large systems, due to the influence of the frequency time-space distribution characteristics, there is a large difference between the frequency change rate near the disturbance point and the frequency change rate of the inertia center.
  • the frequency change rate of the system is constant and the frequency shows a linear downward trend. Therefore, it can be considered that the system frequency deviation and the frequency change rate have an approximately equivalent relationship.
  • the disturbance point and the area where the system inertia center is located are respectively equivalent to two units, and i is used as the power disturbance point, and Gi is the equivalent unit in the area near the disturbance point. It can be obtained:
  • ⁇ represents the proportional coefficient of the frequency change rate of the equivalent unit in the area where the disturbance point is located and the system inertia center is located;
  • RoCoFi represents the frequency change rate of the equivalent unit in the area where the disturbance point is located;
  • RoCoF coi represents the frequency change rate of the equivalent unit in the area where the system inertia center is located;
  • ⁇ fi i represents the frequency change rate of the equivalent unit in the area where the disturbance point is located.
  • the frequency change of the regional equivalent unit; ⁇ f coi represents the frequency change of the equivalent unit in the area where the system inertia center is located.
  • the frequency change rate constraint of the inertia center measured in the system can be transformed into the frequency change rate constraint of the near disturbance point in the system, and the minimum safe inertia required for the system considering the frequency space distribution characteristics is obtained as:
  • determining the change in load power due to frequency change includes: obtaining the active power of the load in the power grid system and the voltage of the load node before the disturbance occurs; determining a first power change based on the active power of the load and the voltage of the load node, wherein the first power change is the change in load power due to voltage change; determining the power change exceeding a third threshold generated by the power grid system under the influence of the disturbance as a second power change; and determining the change in load power due to frequency change as the difference between the first power change and the second power change.
  • ⁇ P is the power imbalance generated after the system is disturbed
  • ⁇ PL is the power imbalance reduced due to the load voltage characteristics after the voltage changes, that is, the change in load power ⁇ PL is:
  • PL is the active power of the load before the disturbance
  • U L0 is the voltage of the load node before the disturbance
  • U L is the voltage of the load node after the disturbance
  • l z , l i , l p respectively represent the proportion of constant impedance load, constant current load and constant power load in the system to the total load.
  • the power imbalance amount affected by the load voltage characteristics of the system i.e., ⁇ PL
  • the maximum power imbalance amount generated after the system disturbance i.e., ⁇ Pmax
  • the part of the maximum power imbalance amount generated after the system disturbance that needs to be supported by the system's safety inertia i.e., ⁇ Pmax - ⁇ PL
  • the minimum safety inertia required for the system considering the frequency-space distribution characteristics is obtained as follows:
  • determining a second safety inertia to ensure safe operation of the power grid system when the frequency is lower than a second threshold after a disturbance occurs in the power grid system includes: obtaining the rated lower limit frequency of the power grid system; and when the frequency is the rated lower limit frequency after a disturbance occurs in the power grid system, determining that the inertia to ensure safe operation of the power grid system is the second safety inertia.
  • determining the inertia for ensuring the safe operation of the power grid system to be the second safety inertia includes: obtaining the rated frequency of the power grid system, the damping coefficient of the power grid system, the primary frequency modulation rate of the power grid system under the disturbance, and the primary frequency modulation action time; when the frequency of the power grid system is at the rated lower limit frequency after a disturbance occurs in the power grid system, determining the inertia for ensuring the safe operation of the power grid system to be the second safety inertia based on the rated frequency of the power grid system, the damping coefficient of the power grid system, the primary frequency modulation rate of the power grid system under the disturbance, and the primary frequency modulation action time.
  • the frequency variation exceeds 0.033 Hz, it crosses the dead zone of the speed regulator. At this time, the speed regulator will increase the mechanical power input to reduce the system power deviation, thereby suppressing the frequency drop. Generally, it is approximately considered that when the mechanical power input and the electromagnetic power output are equal, the system frequency reaches the minimum value f nadir .
  • the lowest frequency point is also a key indicator for measuring the stability of the system frequency. It is necessary to meet the requirement that the lowest system frequency value f nadir is greater than or equal to the rated minimum frequency value f min of the system:
  • the system can be regarded as a synchronous machine, and the frequency response process of the system can be described by the rotor motion equation as follows:
  • Hsys is the overall inertia of the system
  • f(t) is the system frequency at time t
  • Pm (t) and Pe (t) represent the total mechanical power and total electromagnetic power of the system respectively
  • D represents the damping effect in the frequency response process of the system
  • ⁇ f(t) represents the deviation between the frequency of the system at time t and the rated frequency, where the rated frequency is generally 50 Hz.
  • FIG. 5 is a schematic diagram of the frequency response curve after linearization processing provided in accordance with an embodiment of the present application.
  • the present application linearizes the primary frequency modulation effect of the generator set as shown in Figure 5, and solves the minimum safe inertia of the system by applying constraints to the lowest frequency point.
  • the system frequency After the system is disturbed, the system frequency begins to deviate from the normal level and soon crosses the primary frequency regulation dead zone of the generator set. Then the primary frequency regulation starts to act to fill the unbalanced power of the system. When the active power at the frequency output end is equal to the initial unbalanced power, the system frequency reaches the extreme value.
  • the linearization technology is used to simulate the frequency dynamic response process of the system after the disturbance ⁇ P occurs in the power system, as shown in Figures 2 and 5. Under this disturbance, the primary frequency modulation rate of the system is:
  • Tsys is the primary frequency modulation rate of the system under disturbance
  • tdb is the primary frequency modulation action time
  • f db is the frequency of the system at time t db .
  • determining the target safety inertia according to the first safety inertia and the second safety inertia includes: determining the maximum value of the first safety inertia and the second safety inertia as the target safety inertia.
  • simulation verification will be carried out from two perspectives: the IEEE 10-machine 39-node system and the actual power grid system.
  • the 10-machine 39-bus system includes 10 generators, 39 busbars, 19 loads and 34 transmission lines; the rated frequency is 50Hz, of which machine No. 1 is the external grid equivalent machine and machine No. 2 is the balancing machine.
  • Scenario 1 All generators in the system are synchronous units.
  • Scenario 2 The two synchronous units No. 5 and No. 6 in the system are replaced with wind turbines. At this time, the proportion of new energy in the system is 18.8%.
  • Scenario 3 The three synchronous units No. 5, No. 6 and No. 9 in the system are replaced with wind turbines. At this time, the proportion of new energy in the system is 32.2%.
  • the frequency change rate of the system at the initial moment of the disturbance and the lowest frequency point are sampled to calculate the minimum safe inertia of the system. Since this system is a large system, the frequency change rate of the system near the disturbance point at the initial moment of the disturbance is more accurate than the frequency change rate of the inertia center. Therefore, when calculating the minimum safe inertia of the system using the frequency change rate constraint, the frequency change rate of the near disturbance point is required.
  • the minimum safe inertia of the system that meets different frequency constraints can be calculated by equations (7) and (15), and the calculation results of the minimum safe inertia of the system under three scenarios are shown in Table 1.
  • a national power grid J in my country was selected to calculate the minimum safe inertia that meets the conditions for stable operation of the system.
  • the total installed capacity of the provincial power grid is 134.4091 million kilowatts, and the installed capacity of new energy accounts for about 14% of the total capacity of the province, of which the installed capacity of wind power accounts for about 8.26% of the total installed capacity of the whole network, and the installed capacity of photovoltaic power accounts for about 5.74% of the total installed capacity of the whole network.
  • the provincial power grid currently has 4 ultra-high voltage direct current transmission lines, and the direct current feed-in power accounts for about 20.98% of the total installed capacity.
  • the proportion of new energy installed capacity in the province will reach 30%.
  • This application takes the province's power grid's summer operation mode in 2019 as an example, and performs simulation calculations in the software.
  • the system's frequency change rate and the time of the lowest frequency point at the initial moment of the disturbance are sampled to calculate the system's minimum safe inertia.
  • the safety inertia determination method of the power grid system in the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course it can also be implemented by hardware, but in many cases the former is a better implementation method.
  • the technical solution of the present application can be embodied in the form of a software product, which is stored in a storage medium (such as a read-only memory ROM/random access memory RAM, a disk, or an optical disk), and includes at least one instruction for enabling a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the method described in each embodiment of the present application.
  • a storage medium such as a read-only memory ROM/random access memory RAM, a disk, or an optical disk
  • a terminal device which can be a mobile phone, a computer, a server, or a network device, etc.
  • FIG6 is a structural block diagram of the safe inertia determination device for a power grid system provided according to an embodiment of the present application. As shown in FIG6, the safe inertia determination device for the power grid system The device includes: a first determination module 72, a second determination module 74 and a third determination module 76. The safety inertia determination device of the power grid system is described below.
  • the first determination module 72 is configured to determine a first safety inertia for ensuring safe operation of the power grid system when a frequency change rate exceeds a first threshold after a disturbance occurs in the power grid system.
  • the second determination module 74 is connected to the first determination module 72 and is configured to determine a second safety inertia for ensuring safe operation of the power grid system when the frequency is lower than a second threshold after a disturbance occurs in the power grid system.
  • the third determination module 76 is connected to the second determination module 74 and is configured to determine a target safety inertia according to the first safety inertia and the second safety inertia, wherein the target safety inertia is a lower limit value of the safety inertia for ensuring safe operation of the power grid system.
  • the first determination module 72, the second determination module 74 and the third determination module 76 correspond to steps S302 to S306 in the embodiment, and the examples and application scenarios implemented by the multiple modules and the corresponding steps are the same. It should be noted that the above modules can be run in the computer terminal 10 provided in the embodiment as part of the device.
  • the embodiment of the present application further provides a computer device, which may be located in at least one network device among a plurality of network devices of a computer network.
  • the computer device includes a memory and a processor.
  • the memory can be used to store software programs and modules, such as the program instructions/modules corresponding to the method and device for determining the safety inertia of the power grid system in the embodiment of the present application.
  • the processor executes various functional applications and data processing by running the software programs and modules stored in the memory, that is, the above-mentioned method for determining the safety inertia of the power grid system is realized.
  • the memory may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory.
  • the memory may include a memory remotely arranged relative to the processor, and these remote memories may be connected to the computer terminal via a network. Examples of the above-mentioned network include the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.
  • the processor can call the information and application stored in the memory through the transmission device to perform the following steps: determine a first safety inertia that ensures the safe operation of the power grid system when the frequency change rate exceeds a first threshold after a disturbance occurs in the power grid system; determine a second safety inertia that ensures the safe operation of the power grid system when the frequency is lower than a second threshold after a disturbance occurs in the power grid system; determine a target safety inertia based on the first safety inertia and the second safety inertia, wherein the target safety inertia is the lower limit value of the safety inertia that ensures the safe operation of the power grid system.
  • the processor may also execute program code for the following steps: determining a first safety inertia for ensuring safe operation of the power grid system when the frequency change rate exceeds a first threshold after a disturbance occurs in the power grid system, including: obtaining the rated frequency of the power grid system; determining the frequency change rate of the power grid system near the disturbance point; determining the change in load power caused by the frequency change; determining the first safety inertia based on the rated frequency, the frequency change rate of the near disturbance point, and the change in load power caused by the frequency change.
  • the processor may further execute the following steps:
  • the frequency change rate of the near disturbance point of the system includes: obtaining the frequency change rate of the inertia center of the power grid system; determining the proportional relationship between the frequency change rate of the near disturbance point and the frequency change rate of the inertia center; and determining the frequency change rate of the near disturbance point according to the proportional relationship and the frequency change rate of the inertia center.
  • the processor may also execute program code for the following steps: determining the amount of change in load power caused by frequency change, including: obtaining the active power of the load in the power grid system and the voltage of the load node before the disturbance occurs; determining a first power change based on the active power of the load and the voltage of the load node, wherein the first power change is the amount of change in load power caused by voltage change; determining the amount of power change exceeding a third threshold generated by the power grid system under the influence of the disturbance as a second power change; determining the amount of change in load power caused by frequency change as the difference between the first power change and the second power change.
  • the processor may also execute program code for the following steps: determining a second safety inertia that ensures safe operation of the power grid system when the frequency is lower than a second threshold after a disturbance occurs in the power grid system, including: obtaining the rated lower limit frequency of the power grid system; when the frequency is the rated lower limit frequency after a disturbance occurs in the power grid system, determining that the inertia that ensures safe operation of the power grid system is the second safety inertia.
  • the processor may also execute program code for the following steps: when the frequency of the power grid system is at the rated lower limit frequency after a disturbance occurs in the power grid system, determining that the inertia for ensuring the safe operation of the power grid system is the second safety inertia, including: obtaining the rated frequency of the power grid system, the damping coefficient of the power grid system, the primary frequency modulation rate of the power grid system under the disturbance, and the primary frequency modulation action time; when the frequency of the power grid system is at the rated lower limit frequency after a disturbance occurs in the power grid system, determining that the inertia for ensuring the safe operation of the power grid system is the second safety inertia based on the rated frequency of the power grid system, the damping coefficient of the power grid system, the primary frequency modulation rate of the power grid system under the disturbance, and the primary frequency modulation action time.
  • the processor may further execute program code of the following steps: determining a target safety inertia according to the first safety inertia and the second safety inertia, including: determining the maximum value of the first safety inertia and the second safety inertia as the target safety inertia.
  • a scheme for determining the safe inertia of a power grid system is provided.
  • the minimum safe inertia for ensuring the safe operation of the power grid system in the process after the power grid is disturbed is determined, and the minimum safe inertia required by the power grid in various situations is considered, and the minimum safe inertia for ensuring the safe operation of the power grid system in the process after the power grid is disturbed is comprehensively determined, thereby achieving the technical effect of improving the accuracy of determining the minimum safe inertia of the power grid system, and further solving the technical problem of low accuracy
  • a person of ordinary skill in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing the hardware related to the terminal device through a program, and the program can be stored in a non-volatile storage medium, and the storage medium may include: a flash drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.
  • An embodiment of the present application further provides a non-volatile storage medium, which can be used to store program codes executed by the method for determining the safety inertia of a power grid system provided by the above embodiment.
  • the non-volatile storage medium may be located in any computer terminal in a computer terminal group in a computer network, or in any mobile terminal in a mobile terminal group.
  • the non-volatile storage medium is configured to store program codes for performing the following steps: determining a first safety inertia for ensuring safe operation of the power grid system when the frequency change rate exceeds a first threshold after a disturbance occurs in the power grid system; determining a second safety inertia for ensuring safe operation of the power grid system when the frequency is lower than a second threshold after a disturbance occurs in the power grid system; and determining a target safety inertia based on the first safety inertia and the second safety inertia, wherein the target safety inertia is a lower limit value of the safety inertia for ensuring safe operation of the power grid system.
  • the non-volatile storage medium is configured to store program code for executing the following steps: determining a first safety inertia to ensure safe operation of the power grid system when the frequency change rate exceeds a first threshold after a disturbance occurs in the power grid system, including: obtaining the rated frequency of the power grid system; determining the frequency change rate of the power grid system near the disturbance point; determining the change in load power caused by the frequency change; determining the first safety inertia based on the rated frequency, the frequency change rate of the near disturbance point and the change in load power caused by the frequency change.
  • the non-volatile storage medium is configured to store program code for executing the following steps: determining the frequency change rate of a near disturbance point of a power grid system, including: obtaining the frequency change rate of an inertia center of the power grid system; determining a proportional relationship between the frequency change rate of a near disturbance point and the frequency change rate of the inertia center; and determining the frequency change rate of a near disturbance point based on the proportional relationship and the frequency change rate of the inertia center.
  • the non-volatile storage medium is configured to store program code for performing the following steps: determining the change in load power caused by frequency change, including: obtaining the active power of the load in the power grid system and the voltage of the load node before the disturbance occurs; determining a first power change based on the active power of the load and the voltage of the load node, wherein the first power change is the change in load power caused by voltage change; determining a power change exceeding a third threshold generated by the power grid system under the influence of the disturbance as a second power change; determining the change in load power caused by the frequency change as the difference between the first power change and the second power change.
  • the non-volatile storage medium is configured to store program code for executing the following steps: determining a second safety inertia that ensures safe operation of the power grid system when the frequency is lower than a second threshold after a disturbance occurs in the power grid system, including: obtaining the rated lower limit frequency of the power grid system; when the frequency is the rated lower limit frequency after a disturbance occurs in the power grid system, determining that the inertia that ensures safe operation of the power grid system is the second safety inertia.
  • the non-volatile storage medium is configured to store program codes for executing the following steps: when the frequency of the power grid system is at the rated lower limit frequency after a disturbance occurs in the power grid system, determining that the inertia for ensuring the safe operation of the power grid system is the second safety inertia, including: obtaining the rated frequency of the power grid system, the power grid the damping coefficient of the system, the primary frequency modulation rate and the primary frequency modulation action time of the power grid system under disturbance; when the frequency of the power grid system is the rated lower limit frequency after the disturbance occurs in the power grid system, the inertia for ensuring the safe operation of the power grid system is determined as the second safety inertia according to the rated frequency of the power grid system, the damping coefficient of the power grid system, the primary frequency modulation rate and the primary frequency modulation action time of the power grid system under disturbance.
  • the non-volatile storage medium is configured to store program code for executing the following steps: determining a target safety inertia based on the first safety inertia and the second safety inertia, including: determining the maximum value of the first safety inertia and the second safety inertia as the target safety inertia.
  • the disclosed technical content can be implemented in other ways.
  • the device embodiments described above are schematic.
  • the division of the units can be a logical function division. There may be other division methods in actual implementation.
  • multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.
  • Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.
  • the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed over multiple units. Some or all of the units may be selected to implement this embodiment according to actual needs.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.
  • the above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.
  • the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile storage medium.
  • the computer software product is stored in a storage medium and includes at least one instruction to enable a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application.
  • the aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, read-only memories, random access memories, mobile hard disks, magnetic disks or optical disks.

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Abstract

一种电网系统的安全惯量确定方法、装置和计算机设备，其中，该方法包括：确定在电网系统出现扰动后频率变化率超过第一阈值的情况下保证电网系统安全运行的第一安全惯量(S302)；确定在电网系统出现扰动后频率低于第二阈值的情况下保证电网系统安全运行的第二安全惯量(S304)；根据第一安全惯量和第二安全惯量，确定目标安全惯量，其中，目标安全惯量为保证电网系统安全运行的安全惯量下限值(S306)。

Description

电网系统的安全惯量确定方法、装置和计算机设备
本申请要求在2023年06月20日提交中国专利局、申请号为202310739180.4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
本申请涉及电力系统控制领域，例如涉及一种电网系统的安全惯量确定方法、装置和计算机设备。
背景技术
大量新能源发电机组通过使用电力电子器件的方式接入电网，使得新能源机组的传输功率与电网频率解耦，在常规控制模式下发生有功扰动时无法为电网提供惯量支撑，这使得在新能源机组增速高于常规同步机组或者新能源机组取代同步机组时将引起系统的惯量水平下降。而电网系统在发生扰动后，惯量不仅可以延缓系统频率的快速变化，为系统一次调频赢得动作时间，同时也可优化系统频率响应，使扰动后系统频率最低点不越限。因此，当系统在发生极端扰动时，惯量的减小会导致系统频率出现迅速飙升或跌落的现象，恶化系统频率响应，使得系统频率最低点越过电网第三道防线动作值，使系统面临大范围切机、切负荷的风险。因此，为避免系统陷入惯量短缺的运行困境，需要计算保障系统能够安全稳定运行的最小惯量，为运行人员调整惯量水平提供参考。
相关技术关于系统最小安全惯量的研究大多通过频率初始变化率约束与频率最低点约束单一约束获取，且考虑因素不全面；同时缺乏对频率时空分布特性考虑。
发明内容
本申请实施例提供了一种电网系统的安全惯量确定方法、装置和计算机设备，以至少解决相关技术中确定电网系统的最小安全惯量的方法准确率低的技术问题。
根据本申请实施例的一个方面，提供了一种电网系统的安全惯量确定方法，包括：确定在电网系统出现扰动后频率变化率超过第一阈值的情况下保证电网系统安全运行的第一安全惯量；确定在电网系统出现扰动后频率低于第二阈值的情况下保证电网系统安全运行的第二安全惯量；根据第一安全惯量和第二安全惯量，确定目标安全惯量，其中，目标安全惯量为保证电网系统安全运行的安全惯量下限值。
在一些实施例中，确定在电网系统出现扰动后频率变化率超过第一阈值的情况下保证电网系统安全运行的第一安全惯量，包括：获取电网系统的额定频率；确定电网系统的近扰动点的频率变化率；确定由于频率变化引起的负荷功率的变化量；根据额定频率、近扰动点的频率变化率和由于频率变化引起的负荷功率的变化量，确定第一安全惯量。
在一些实施例中，确定电网系统的近扰动点的频率变化率，包括：获取电网系统的惯量中心的频率变化率；确定近扰动点的频率变化率与惯量中心的频率变化率的比例关系；根据比例关系和惯量中心的频率变化率，确定近扰动点的频率变化率。
在一些实施例中，确定由于频率变化引起的负荷功率的变化量，包括：获取在扰动发生前电网系统中负荷的有功功率，以及负荷节点的电压；根据负荷的有功功率和负荷节点的电压，确定第一功率变化量，其中，第一功率变化量为由于电压变化引起的负荷功率的变化量；确定在扰动的影响下电网系统产生的超过第三阈值的功率变化量为第二功率变化量；确定由于频率变化引起的负荷功率的变化量为第一功率变化量与第二功率变化量的差。
在一些实施例中，确定在电网系统出现扰动后频率低于第二阈值的情况下保证电网系统安全运行的第二安全惯量，包括：获取电网系统的额定下限频率；响应于电网系统出现扰动后频率为额定下限频率，确定保证电网系统安全运行的惯量为第二安全惯量。
在一些实施例中，响应于电网系统出现扰动后频率为额定下限频率，确定保证电网系统安全运行的惯量为第二安全惯量，包括：获取电网系统的额定频率、电网系统的阻尼系数、在扰动下电网系统的一次调频速率和一次调频动作时间；响应于电网系统出现扰动后频率为额定下限频率，根据电网系统的额定频率、电网系统的阻尼系数、在扰动下电网系统的一次调频速率和一次调频动作时间，确定保证电网系统安全运行的惯量为第二安全惯量。
在一些实施例中，根据第一安全惯量和第二安全惯量，确定目标安全惯量，包括：确定第一安全惯量和第二安全惯量中的最大值为目标安全惯量。
根据本申请实施例的另一方面，还提供了一种电网系统的安全惯量确定装置，包括：第一确定模块，设置为确定在电网系统出现扰动后频率变化率超过第一阈值的情况下保证电网系统安全运行的第一安全惯量；第二确定模块，设置为确定在电网系统出现扰动后频率低于第二阈值的情况下保证电网系统安全运行的第二安全惯量；第三确定模块，设置为根据第一安全惯量和第二安全惯量，确定目标安全惯量，其中，目标安全惯量为保证电网系统安全运行的安全惯量下限值。
根据本申请实施例的又一方面，还提供了一种非易失性存储介质，非易失性存储介质包括存储的程序，其中，在程序运行时控制非易失性存储介质所在设备执行上述中任意一项电网系统的安全惯量确定方法。
根据本申请实施例的再一方面，还提供了一种计算机设备，计算机设备包括处理器，处理器用于运行程序，其中，程序运行时执行上述中任意一项电网系统的安全惯量确定方法。
附图说明
此处所说明的附图用来提供对本申请的理解，构成本申请的一部分，本申请的示意性实施例及其说明用于解释本申请。在附图中：
图1示出了一种用于实现电网系统的安全惯量确定方法的计算机终端的硬件结构框图；
图2示出了一种电网系统频域响应过程的示意图；
图3是根据本申请实施例提供的电网系统的安全惯量确定方法的流程示意图；
图4是根据本申请实施例提供的负荷电压特性功率响应的示意图；
图5是根据本申请实施例提供的线性化处理后的频率响应曲线的示意图；
图6是根据本申请实施例提供的电网系统的安全惯量确定装置的结构框图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例进行描述，所描述的实施例是本申请相关的一些实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都应当属于本申请保护的范围。
本申请的说明书和权利要求书及上述附图中的术语“第一”、“第二”等是用于区别类似的对象，而不必用于描述特定的顺序或先后次序。应该理解这样使用的数据在适当情况下可以互换，以便这里描述的本申请的实施例能够以除了在这里图示或描述的那些以外的顺序实施。此外，术语“包括”和“具有”以及他们的任何变形，意图在于覆盖不排他的包含，例如，包含了一系列步骤或单元的过程、方法、系统、产品或设备不必限于列出的那些步骤或单元，而是可包括没有列出的或对于这些过程、方法、产品或设备固有的其它步骤或单元。
根据本申请实施例，提供了一种电网系统的安全惯量确定方法的实施例，在附图的流程图示出的步骤可以在诸如一组计算机可执行指令的计算机系统中执行，并且，虽然在流程图中示出了逻辑顺序，但是在一些情况下，可以以不同于此处的顺序执行所示出或描述的步骤。
本申请实施例一所提供的方法实施例可以在移动终端、计算机终端或者类似的运算装置中执行。图1示出了一种用于实现电网系统的安全惯量确定方法 的计算机终端的硬件结构框图。如图1所示，计算机终端10可以包括一个或多个(图中采用102a、102b，……，102n来示出)处理器(处理器可以包括微处理器MCU或可编程逻辑器件FPGA等的处理装置)、用于存储数据的存储器104。除此以外，计算机终端10还可以包括：显示器、输入/输出接口(I/O接口)、通用串行总线(USB)端口(可以作为BUS总线的端口中的一个端口被包括)、网络接口、电源和/或相机。本领域普通技术人员可以理解，图1所示的结构为示意。例如，计算机终端10还可包括比图1中所示更多或者更少的组件，或者具有与图1所示不同的配置。
上述一个或多个处理器和/或其他数据处理电路在本文中通常可以被称为“数据处理电路”。该数据处理电路可以全部或部分的体现为软件、硬件、固件或其他任意组合。此外，数据处理电路可为单个独立的处理模块，或全部或部分的结合到计算机终端10中的其他元件中的任意一个内。如本申请实施例中所涉及到的，该数据处理电路作为一种处理器控制(例如与接口连接的可变电阻终端路径的选择)。
存储器104可用于存储应用软件的软件程序以及模块，如本申请实施例中的电网系统的安全惯量确定方法对应的程序指令/数据存储装置，处理器通过运行存储在存储器104内的软件程序以及模块，从而执行各种功能应用以及数据处理，即实现上述的应用程序的电网系统的安全惯量确定方法。存储器104可包括高速随机存储器，还可包括非易失性存储器，如一个或者多个磁性存储装置、闪存、或者其他非易失性固态存储器。在一些实例中，存储器104可包括相对于处理器远程设置的存储器，这些远程存储器可以通过网络连接至计算机终端10。上述网络的实例包括互联网、企业内部网、局域网、移动通信网及其组合。
显示器可以为例如触摸屏式的液晶显示器(Liquid Crystal Display，LCD)，该液晶显示器可使得用户能够与计算机终端10的用户界面进行交互。
当电力系统发生扰动时，按照时间顺序可将发电机组参与调频的过程分为惯量响应阶段，一次调频阶段以及二次调频阶段，在不同的响应阶段有不同的调频方法对电网产生的不平衡功率进行调整。图2示出了一种电网系统频域响应过程的示意图，如图2所示，可将系统的频率响应过程分为如下几个阶段。
阶段1：在扰动产生的瞬间t1，存在着两个进程，一个是扰动功率的重新分配，此进程实际是每个发电机组按照同步功率系数分配扰动功率，如式(1)所示，表示的含义为当系统中负荷k处发生有功扰动ΔP时，也即系统发生扰动后产生的功率不平衡量为ΔP时，第i台发电机的输出电磁功率Pei变为原始功率与扰动功率的叠加值。第二个进程是负荷电压特性影响电网系统运行，它通过改变系统在扰动后的不平衡功率，在系统频率响应时起着类似惯量的作用。
式中，Ei和Ej分别表示第i台和第j台发电机的暂态电势，Uk为负荷k两端的电压值，Gii为系统节点导纳矩阵Y中对角元素，即在节点i的自导纳，Bij是节点i和节点j之间的互电纳；Bik是节点i和节点k之间的互电纳；Gij是节点i和节点j之间的互电导；Gik是节点i和节点k之间的互电导。δij＝δi-δj，δi代表系统中第i台发电机的励磁电势和端电压之间相角差，即功角。δj代表系统中第j台发电机的励磁电势和端电压之间相角差，δij代表系统中第i台发电机和第j台发电机之间的功角差。δik＝δi-δk，δk代表系统中负荷k的相角差，δik代表系统中第i台发电机和负荷k之间的功角差。
阶段2：惯量响应阶段，从t1到t2期间，发生扰动后，同步发电机的电磁功率突增，而机械功率缺保持不变，频率尚处于调速器调频死区而尚未动作。此时由于同步机组的转子在旋转过程中储存了动能，具有一定的转动惯量。在出现功率不平衡后，同步发电机的转子通过加速或减速将其中储存的动能通过功角特性转换为电磁功率，继续维持着系统的有功供需平衡。由于此时系统中仅有惯量作用，系统的频率变化率在此时为最大值，因此一般对此时的频率变化率设定约束，进而求解系统最小安全惯量。对于单台同步发电机，根据转子运动方程可得：
式中：fn为电网额定频率；Hi为第i台同步机组的惯性时间常数；Si为第i台同步机的额定容量；f(t)为电网中频率关于时间变化的函数；ΔPi为同步发电机机械功率与电磁功率间的偏差，在扰动瞬间为发电机承担的扰动功率。
阶段3：此时系统中惯量响应与一次调频响应共同作用。在t2时刻，系统的频率偏差超过了调速器调频死区，调速器发出调节信号后，原动机阀门开度增大，增加向系统的机械功率输出，使得不平衡功率减小，系统惯量支撑功率也逐渐减小，当系统的不平衡功率降为零时，系统频率到达最低点。
阶段4：频率到达最低点后，机组继续增发功率，使得系统的机械功率大于电磁功率，同步发电机转子开始吸收能量恢复部分转速，此时系统的惯量响应由正变负，系统频率在t3时刻达到新的平衡，维持在较低水平，系统机械功率不再增加。
阶段5：t3时刻后为二次调频响应阶段。由于一次调频为有差调频，在稳态频率偏差较大时，需启动二次调频，增加调频厂内有功出力，将频率调节至系统频率额定值。
由于调速器存在着频率不灵敏区和响应延时，在出现有功扰动时，同步机无法立即向系统中注入功率以消除不平衡功率。因此，在调速器动作前，仅可以靠惯性的支撑维持着供需平衡。而惯量可视为发电机转子中的储能，在无额外功率注入系统的情况下，在出现有功扰动后仅靠惯量的调节，系统频率会以恒定速率持续下降至零。
综上所述，当系统出现不平衡功率时，由于无法瞬时平衡，因而惯量在维持有功供需平衡方法发挥着重要的作用，为电磁功率提供能量来源，从而维持着有功的供需平衡，并减缓系统频率变化的速率，为一次调频的作用赢得时间，是维持系统频率稳定不可或缺的一部分。因此本申请将求解满足系统稳定运行需求的最小安全惯量。
由于扰动后频率的动态过程与系统运行状态、有功扰动类型、大小及位置等因素有关，因此，在选取频率指标，应当选取典型特征指标进行约束后再进行惯量的计算。
图3是根据本申请实施例提供的电网系统的安全惯量确定方法的流程示意图，如图3所示，该方法包括如下步骤：
步骤S302，确定在电网系统出现扰动后频率变化率超过第一阈值的情况下保证电网系统安全运行的第一安全惯量。
本步骤中，可以选择频率变化率作为特征指标进行约束，计算当电网系统在扰动的影响下频率变化率超过第一阈值时，能够保证电网系统安全运行的第一安全惯量。示例性地，在电力系统发生扰动时，在扰动初始时刻频率变化率最大，可以计算电网系统频率变化率最大时需要的安全惯量为第一安全惯量。
步骤S304，确定在电网系统出现扰动后频率低于第二阈值的情况下保证电网系统安全运行的第二安全惯量。
本步骤中，可以选择频率作为特征指标进行约束，计算当电网系统在扰动的影响下频率低于第二阈值时，能够保证电网系统安全运行的第二安全惯量。示例性地，当电网系统发生有功扰动后，频率变化率第一次降为0时所对应的频率大小，也就是频率的极值，一般地，近似认为当机械功率输入和电磁功率输出相等时，系统频率到达最低值，可以计算电网系统频率最低时需要的安全惯量为第二安全惯量。
步骤S306，根据第一安全惯量和第二安全惯量，确定目标安全惯量，其中，目标安全惯量为保证电网系统安全运行的安全惯量下限值。
本步骤中，可以综合考虑频率变化率最大和频率最低的情况下，电网系统分别需要的安全惯量，最终确定电网系统安全运行的最小安全惯量，也即安全惯量下限值。
通过分别计算电网系统出现扰动后频率变化率最大的情况下保证电网系统安全运行的第一安全惯量，以及电网系统出现扰动后频率最低的情况下保证电网系统安全运行的第二安全惯量，并且综合考虑第一安全惯量和第二安全惯量，确定电网受到扰动后的过程中保证电网系统安全运行的最小安全惯量，达到了考虑多种情况下电网需要的最小安全惯量，综合确定电网受到扰动后的过程中保证电网系统安全运行的最小安全惯量的效果，从而达到了提高确定电网系统的最小安全惯量的准确率的技术效果，进而解决了相关技术中确定电网系统的最小安全惯量的方法准确率低的技术问题。
在一些实施例中，确定在电网系统出现扰动后频率变化率超过第一阈值的情况下保证电网系统安全运行的第一安全惯量，包括：获取电网系统的额定频率；确定电网系统的近扰动点的频率变化率；确定由于频率变化引起的负荷功率的变化量；根据额定频率、近扰动点的频率变化率和由于频率变化引起的负荷功率的变化量，确定第一安全惯量。
在一些实施例中，确定电网系统的近扰动点的频率变化率，包括：获取电网系统的惯量中心的频率变化率；确定近扰动点的频率变化率与惯量中心的频率变化率的比例关系；根据比例关系和惯量中心的频率变化率，确定近扰动点的频率变化率。
示例性地，在扰动出现的瞬间系统的频率变化率最大，若以扰动后频率变化率不超过一门槛值为约束，则应以扰动瞬间频率变化率为基准。此时无频率偏差，即无发电机调速器和负荷频率调节效应。由公式(3)得，基于频率变化率约束的系统最小安全惯量Hmin为：
式中，ΔPmax为系统可能发生的最大扰动功率，一般为系统发生交流联络线断线、直流闭锁或者系统中最大的发电机组退出运行时系统发生的扰动功率。RoCoFmax表示系统允许的惯量中心的频率变化率的极限值。
但是，上式中RoCoFmax表示的是系统惯量中心的频率变化率，而频率约束通常是以系统最大母线频率或特定母线频率为依据，一般位于近扰动点。对于小系统而言，频率时空分布特性并不明显，近扰动点的频率变化率与惯量中心的频率变化率近似相等；但对于大系统而言，由于频率时空分布特性的影响，近扰动点的频率变化率与惯量中心的频率变化率存在着较大的差异，因此对于大系统需要量化近扰动点与惯量中心的频率变化率的关系，以近扰动点的频率变化率表示惯量中心的频率变化率，并采用近扰动点的频率变化率计算第一安全惯量。
在惯量响应阶段，由于此时调速器尚未动作，因而可认为此时系统的频率变化率恒定，频率呈线性下降的趋势，因而可认为系统频率偏差与频率变化率有着近似等价的关系。分别将扰动点与系统惯量中心所在区域等效成两台机组，并将i作为功率扰动点，Gi为近扰动点所在区域等值机组。可得：
式中，α表示的是扰动点与系统惯量中心所在区域等效机组的频率变化率的比例系数；RoCoFi表示的是扰动点所在区域等效机组的频率变化率；RoCoFcoi表示的是系统惯量中心所在区域等效机组的频率变化率；Δfii表示的是扰动点所在 区域等效机组的频率变化量；Δfcoi表示的是系统惯量中心所在区域等效机组的频率变化量。
将(4)代入(3)中，可将系统中量测的惯量中心的频率变化率约束转化为系统中近扰动点的频率变化率约束，得到考虑频率空间分布特征的系统所需最小安全惯量为：
在一些实施例中，确定由于频率变化引起的负荷功率的变化量，包括：获取在扰动发生前电网系统中负荷的有功功率，以及负荷节点的电压；根据负荷的有功功率和负荷节点的电压，确定第一功率变化量，其中，第一功率变化量为由于电压变化引起的负荷功率的变化量；确定在扰动的影响下电网系统产生的超过第三阈值的功率变化量为第二功率变化量；确定由于频率变化引起的负荷功率的变化量为第一功率变化量与第二功率变化量的差。
在一些实施例中，扰动的出现不仅会影响系统频率，同时也会影响系统电压。电压的变化将会使系统中恒阻抗、恒电流负荷功率都发生相应的变化，减小了系统的不平衡功率，进而减小了扰动后频率变化率，图4是根据本申请实施例提供的负荷电压特性功率响应的示意图，如图4所示，其本质是改变了系统的不平衡功率。随着新能源在电网中的比例不断增大，负荷电压特性在减缓系统频率变化率方面所起的作用越来越明显。
图4中ΔP为系统发生扰动后产生的功率不平衡量，ΔPL为电压变化后由于负荷电压特性而减小的功率不平衡量，即负荷功率的改变量ΔPL为：
式中：PL为扰动前负荷的有功功率；UL0为扰动前负荷节点的电压；UL为扰动后负荷节点的电压；lz、li、lp分别表示系统中恒阻抗负荷、恒电流负荷、恒功率负荷占总负荷的比例。
将(6)代入(5)中，可以在系统扰动后所产生的最大的功率不平衡量(即ΔPmax)中去除被系统的负荷电压特性影响的功率不平衡量(即ΔPL)，得到系统扰动后所产生的最大的功率不平衡量中需要系统的安全惯量来支撑的部分(即ΔPmax-ΔPL)，最终得到考虑频率空间分布特征的系统所需最小安全惯量为：
在一些实施例中，确定在电网系统出现扰动后频率低于第二阈值的情况下保证电网系统安全运行的第二安全惯量，包括：获取电网系统的额定下限频率；在电网系统出现扰动后频率为额定下限频率的情况下，确定保证电网系统安全运行的惯量为第二安全惯量。
在一些实施例中，在电网系统出现扰动后频率为额定下限频率的情况下，确定保证电网系统安全运行的惯量为第二安全惯量，包括：获取电网系统的额定频率、电网系统的阻尼系数、在扰动下电网系统的一次调频速率和一次调频动作时间；在电网系统出现扰动后频率为额定下限频率的情况下，根据电网系统的额定频率、电网系统的阻尼系数、在扰动下电网系统的一次调频速率和一次调频动作时间，确定保证电网系统安全运行的惯量为第二安全惯量。
在一些实施例中，当频率变化超过0.033赫兹(Hz)后，越过调速器调频死区，此时调速器将增加机械功率输入以减少系统功率偏差，从而抑制频率的跌落。一般地，近似认为当机械功率输入和电磁功率输出相等时，系统频率到达最低值fnadir。为避免触发低频减载安稳装置动作，频率最低点也是衡量系统频率稳定的关键指标，需要满足系统频率最低值fnadir大于或等于系统的额定最小频率值fmin：
fmin≤fnadir  (8)
由于同一区域电网的频率曲线在到达频率最低点时趋于一致，因此可将系统等值为一台同步机，利用转子运动方程来描述系统的频率响应过程为：
式中：Hsys为系统整体惯量；f(t)为t时刻的系统频率；Pm(t)、Pe(t)分别表示系统的总机械功率和总电磁功率；D表示系统频率响应过程中的阻尼效应；Δf(t)表示t时刻的系统的频率与额定频率之间的偏差，其中，额定频率一般为50赫兹。
由于在频率下降到最低点的过程中，惯量响应与一次调频响应共同作用，导致频率响应呈现出非线性的的特征，为求解带来难度。图5是根据本申请实施例提供的线性化处理后的频率响应曲线的示意图，为提升求解效率，本申请将发电机组的一次调频作用进行线性化处理后如图5所示，通过对频率最低点施加约束求解系统最小安全惯量。
假定系统频率于tnadir时到达最低点，对式(9)从0至tnadir进行积分，得：
在系统发生扰动后，系统频率开始偏离正常水平，并且很快会越过发电机组一次调频死区，进而一次调频开始动作以填补系统的不平衡功率，当一次调 频输出端有功功率等于初始不平衡功率时，系统频率到达极值。采用线性化技术模拟电力系统发生扰动ΔP后系统的频率动态响应过程如图2、5所示。在此扰动下，系统的一次调频速率为：
式中，Tsys为扰动下系统一次调频速率；tdb为一次调频动作时间。
在0～tdb阶段，此时一次调频尚未启动，系统的功率不平衡量保持ΔP不变，对公式(9)在此阶段积分，可得：
式中，fdb为tdb时刻的系统的频率。
一次调频开始动作后，频率到达最低点的时间为：
对式(9)两边从0至tnadir进行积分可得：
将式(14)代入频率约束式(8)后，得到满足频率最低点的系统安全惯量Hsys为：
公式(15)取左右两边相等时，得到满足频率最低点约束的电力系统所需的最小安全惯量Hsys,min。
在一些实施例中，根据第一安全惯量和第二安全惯量，确定目标安全惯量，包括：确定第一安全惯量和第二安全惯量中的最大值为目标安全惯量。
在一些实施例中，当分别求解得到满足频率变化率约束和频率最低点约束的电力系统最小安全惯量后，需综合考虑求解得到电力系统所需最小安全惯量H：
H＝max{Hmin，Hsys，min}    (16)
作为一实施例，将分别从IEEE 10机39节点系统和实际电网系统两个角度进行仿真验证。
1、IEEE 10机39节点
10机39节点系统中包含10台发电机、39条母线、19处负荷和34条传输线；额定频率为50Hz，其中1号机为外部电网等值机，2号机为平衡机。
在上述10机39节点系统中设置3种场景，在各场景下分别计算两种频率约束下的系统最小安全惯量需求，仿真如下：
场景1：系统中发电机均为同步机组。
场景2：将系统中5号与6号两台同步机组等值更换为风力发电机，此时系统中新能源比例为18.8％。
场景3：将系统中5号、6号与9号三台同步机组等值更换为风力发电机，此时系统中新能源比例为32.2％。
以发生负荷突增事件为例，在扰动发生后，采样扰动初始时刻系统的频率变化率及频率最低点进行系统最小安全惯量计算。由于此系统为大系统，在扰动初始时刻系统近扰动点频率变化率较惯量中心频率变化率更精确，因此在利用频率变化率约束计算系统最小安全惯量时，需用近扰动点频率变化率。由式(7)和式(15)可分别计算得到满足不同频率约束的系统最小安全惯量，在3种场景下的系统最小安全惯量计算结果如表1所示。
表1 10机39节点系统最小安全惯性常数计算结果
由表1可知，在场景1系统中无新能源时，利用本申请所提最小安全惯量计算方法所得结果与理论值相近。同时，新能源占比增大后最小安全惯量计算值与理论值相近可以说明本方法既适用于常规电网，又适用于新能源高占比电网。且通过对比可知，大系统中利用近扰动点频率初始变化率计算最小安全惯量要较惯量中心处更为准确。
2、实际新能源高占比系统
为了分析上述系统最小安全惯量计算方法在实际电网中的适用性，选取我国一省级电网J，计算满足系统稳定运行条件的最小安全惯量。该省级电网现有总装机容量为13440.91万千瓦，新能源装机约占全省总容量的14％，其中风电装机容量约占全网总装机容量的8.26％，光伏装机容量约占全网总装机容量的5.74％。同时该省级电网现有特高压直流输电线路4条，直流馈入功率约占总装机容量的20.98％。此外，依据该省在“十四五”的规划可知，至2025年时，该省的新能源装机占比将达到30％。
本申请以该省电网2019年夏大运行方式为算例，在软件中进行仿真计算，分别在新能源占比14％以及30％的系统中，以发生负荷突增事件为例，在扰动发生后，采样扰动初始时刻系统的频率变化率及频率最低点时刻等数据进行系统最小安全惯量计算。
表2实际电力系统最小安全惯性常数计算结果
由表2可知，在扰动后，利用文中方法在实际电力系统中计算系统最小安全惯量同样具有较高的精度，证明本申请计算电力系统最小安全惯量的方法在实际电力系统中同样适用。
对于前述的各方法实施例，为了简单描述，故将其都表述为一系列的动作组合，但是本领域技术人员应该知悉，本申请并不受所描述的动作顺序的限制，因为依据本申请，一些步骤可以采用其他顺序或者同时进行。其次，本领域技术人员也应该知悉，说明书中所描述的实施例均属于示例性实施例，所涉及的动作和模块并不一定是本申请所必须的。
通过以上的实施方式的描述，本领域的技术人员可以了解到，上述实施例的电网系统的安全惯量确定方法可借助软件加必需的通用硬件平台的方式来实现，当然也可以通过硬件，但很多情况下前者是更佳的实施方式。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质(如只读存储器ROM/随机存储器RAM、磁碟、光盘)中，包括至少一个指令用以使得一台终端设备(可以是手机，计算机，服务器，或者网络设备等)执行本申请各个实施例所述的方法。
根据本申请实施例，还提供了一种用于实施上述电网系统的安全惯量确定方法的电网系统的安全惯量确定装置，图6是根据本申请实施例提供的电网系统的安全惯量确定装置的结构框图，如图6所示，该电网系统的安全惯量确定 装置包括：第一确定模块72、第二确定模块74和第三确定模块76，下面对该电网系统的安全惯量确定装置进行说明。
第一确定模块72，设置为确定在电网系统出现扰动后频率变化率超过第一阈值的情况下保证电网系统安全运行的第一安全惯量。
第二确定模块74，与第一确定模块72连接，设置为确定在电网系统出现扰动后频率低于第二阈值的情况下保证电网系统安全运行的第二安全惯量。
第三确定模块76，与第二确定模块74连接，设置为根据第一安全惯量和第二安全惯量，确定目标安全惯量，其中，目标安全惯量为保证电网系统安全运行的安全惯量下限值。
上述第一确定模块72、第二确定模块74和第三确定模块76对应于实施例中的步骤S302至步骤S306，多个模块与对应的步骤所实现的实例和应用场景相同。需要说明的是，上述模块作为装置的一部分可以运行在实施例提供的计算机终端10中。
本申请的实施例还提供了一种计算机设备，上述计算机设备可以位于计算机网络的多个网络设备中的至少一个网络设备。该计算机设备包括存储器和处理器。
存储器可用于存储软件程序以及模块，如本申请实施例中的电网系统的安全惯量确定方法和装置对应的程序指令/模块，处理器通过运行存储在存储器内的软件程序以及模块，从而执行各种功能应用以及数据处理，即实现上述的电网系统的安全惯量确定方法。存储器可包括高速随机存储器，还可以包括非易失性存储器，如一个或者多个磁性存储装置、闪存、或者其他非易失性固态存储器。在一些实例中，存储器可包括相对于处理器远程设置的存储器，这些远程存储器可以通过网络连接至计算机终端。上述网络的实例包括互联网、企业内部网、局域网、移动通信网及其组合。
处理器可以通过传输装置调用存储器存储的信息及应用程序，以执行下述步骤：确定在电网系统出现扰动后频率变化率超过第一阈值的情况下保证电网系统安全运行的第一安全惯量；确定在电网系统出现扰动后频率低于第二阈值的情况下保证电网系统安全运行的第二安全惯量；根据第一安全惯量和第二安全惯量，确定目标安全惯量，其中，目标安全惯量为保证电网系统安全运行的安全惯量下限值。
在一些实施例中，上述处理器还可以执行如下步骤的程序代码：确定在电网系统出现扰动后频率变化率超过第一阈值的情况下保证电网系统安全运行的第一安全惯量，包括：获取电网系统的额定频率；确定电网系统的近扰动点的频率变化率；确定由于频率变化引起的负荷功率的变化量；根据额定频率、近扰动点的频率变化率和由于频率变化引起的负荷功率的变化量，确定第一安全惯量。
在一些实施例中，上述处理器还可以执行如下步骤的程序代码：确定电网 系统的近扰动点的频率变化率，包括：获取电网系统的惯量中心的频率变化率；确定近扰动点的频率变化率与惯量中心的频率变化率的比例关系；根据比例关系和惯量中心的频率变化率，确定近扰动点的频率变化率。
在一些实施例中，上述处理器还可以执行如下步骤的程序代码：确定由于频率变化引起的负荷功率的变化量，包括：获取在扰动发生前电网系统中负荷的有功功率，以及负荷节点的电压；根据负荷的有功功率和负荷节点的电压，确定第一功率变化量，其中，第一功率变化量为由于电压变化引起的负荷功率的变化量；确定在扰动的影响下电网系统产生的超过第三阈值的功率变化量为第二功率变化量；确定由于频率变化引起的负荷功率的变化量为第一功率变化量与第二功率变化量的差。
在一些实施例中，上述处理器还可以执行如下步骤的程序代码：确定在电网系统出现扰动后频率低于第二阈值的情况下保证电网系统安全运行的第二安全惯量，包括：获取电网系统的额定下限频率；在电网系统出现扰动后频率为额定下限频率的情况下，确定保证电网系统安全运行的惯量为第二安全惯量。
在一些实施例中，上述处理器还可以执行如下步骤的程序代码：在电网系统出现扰动后频率为额定下限频率的情况下，确定保证电网系统安全运行的惯量为第二安全惯量，包括：获取电网系统的额定频率、电网系统的阻尼系数、在扰动下电网系统的一次调频速率和一次调频动作时间；在电网系统出现扰动后频率为额定下限频率的情况下，根据电网系统的额定频率、电网系统的阻尼系数、在扰动下电网系统的一次调频速率和一次调频动作时间，确定保证电网系统安全运行的惯量为第二安全惯量。
在一些实施例中，上述处理器还可以执行如下步骤的程序代码：根据第一安全惯量和第二安全惯量，确定目标安全惯量，包括：确定第一安全惯量和第二安全惯量中的最大值为目标安全惯量。
采用本申请实施例，提供了一种电网系统的安全惯量确定的方案。通过分别计算电网系统出现扰动后频率变化率最大的情况下保证电网系统安全运行的第一安全惯量，以及电网系统出现扰动后频率最低的情况下保证电网系统安全运行的第二安全惯量，并且综合考虑第一安全惯量和第二安全惯量，确定电网受到扰动后的过程中保证电网系统安全运行的最小安全惯量，达到了考虑多种情况下电网需要的最小安全惯量，综合确定电网受到扰动后的过程中保证电网系统安全运行的最小安全惯量的效果，从而达到了提高确定电网系统的最小安全惯量的准确率的技术效果，进而解决了相关技术中确定电网系统的最小安全惯量的方法准确率低的技术问题。
本领域普通技术人员可以理解上述实施例的各种方法中的全部或部分步骤是可以通过程序来指令终端设备相关的硬件来完成，该程序可以存储于一非易失性存储介质中，存储介质可以包括：闪存盘、只读存储器(Read-Only Memory，ROM)、随机存储器(Random Access Memory，RAM)、磁盘或光盘等。
本申请的实施例还提供了一种非易失性存储介质，上述非易失性存储介质可以用于保存上述实施例所提供的电网系统的安全惯量确定方法所执行的程序代码。
在一些实施例中，上述非易失性存储介质可以位于计算机网络中计算机终端群中的任意一个计算机终端中，或者位于移动终端群中的任意一个移动终端中。
在一些实施例中，非易失性存储介质被设置为存储用于执行以下步骤的程序代码：确定在电网系统出现扰动后频率变化率超过第一阈值的情况下保证电网系统安全运行的第一安全惯量；确定在电网系统出现扰动后频率低于第二阈值的情况下保证电网系统安全运行的第二安全惯量；根据第一安全惯量和第二安全惯量，确定目标安全惯量，其中，目标安全惯量为保证电网系统安全运行的安全惯量下限值。
在一些实施例中，非易失性存储介质被设置为存储用于执行以下步骤的程序代码：确定在电网系统出现扰动后频率变化率超过第一阈值的情况下保证电网系统安全运行的第一安全惯量，包括：获取电网系统的额定频率；确定电网系统的近扰动点的频率变化率；确定由于频率变化引起的负荷功率的变化量；根据额定频率、近扰动点的频率变化率和由于频率变化引起的负荷功率的变化量，确定第一安全惯量。
在一些实施例中，非易失性存储介质被设置为存储用于执行以下步骤的程序代码：确定电网系统的近扰动点的频率变化率，包括：获取电网系统的惯量中心的频率变化率；确定近扰动点的频率变化率与惯量中心的频率变化率的比例关系；根据比例关系和惯量中心的频率变化率，确定近扰动点的频率变化率。
在一些实施例中，非易失性存储介质被设置为存储用于执行以下步骤的程序代码：确定由于频率变化引起的负荷功率的变化量，包括：获取在扰动发生前电网系统中负荷的有功功率，以及负荷节点的电压；根据负荷的有功功率和负荷节点的电压，确定第一功率变化量，其中，第一功率变化量为由于电压变化引起的负荷功率的变化量；确定在扰动的影响下电网系统产生的超过第三阈值的功率变化量为第二功率变化量；确定由于频率变化引起的负荷功率的变化量为第一功率变化量与第二功率变化量的差。
在一些实施例中，非易失性存储介质被设置为存储用于执行以下步骤的程序代码：确定在电网系统出现扰动后频率低于第二阈值的情况下保证电网系统安全运行的第二安全惯量，包括：获取电网系统的额定下限频率；在电网系统出现扰动后频率为额定下限频率的情况下，确定保证电网系统安全运行的惯量为第二安全惯量。
在一些实施例中，非易失性存储介质被设置为存储用于执行以下步骤的程序代码：在电网系统出现扰动后频率为额定下限频率的情况下，确定保证电网系统安全运行的惯量为第二安全惯量，包括：获取电网系统的额定频率、电网 系统的阻尼系数、在扰动下电网系统的一次调频速率和一次调频动作时间；在电网系统出现扰动后频率为额定下限频率的情况下，根据电网系统的额定频率、电网系统的阻尼系数、在扰动下电网系统的一次调频速率和一次调频动作时间，确定保证电网系统安全运行的惯量为第二安全惯量。
在一些实施例中，非易失性存储介质被设置为存储用于执行以下步骤的程序代码：根据第一安全惯量和第二安全惯量，确定目标安全惯量，包括：确定第一安全惯量和第二安全惯量中的最大值为目标安全惯量。
上述本申请实施例序号是为了描述，不代表实施例的优劣。
在本申请的上述实施例中，对各个实施例的描述都各有侧重，一个实施例中没有详述的部分，可以参见其他实施例的相关描述。
在本申请所提供的几个实施例中，所揭露的技术内容，可通过其它的方式实现。其中，以上所描述的装置实施例是示意性的，例如所述单元的划分，可以为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，单元或模块的间接耦合或通信连接，可以是电性或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。
所述集成的单元如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个非易失性取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的全部或部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括至少一个指令用以使得一台计算机设备(可为个人计算机、服务器或者网络设备等)执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、只读存储器、随机存取存储器、移动硬盘、磁碟或者光盘等各种可以存储程序代码的介质。

Claims (10)

  1. 一种电网系统的安全惯量确定方法，包括：
    确定在电网系统出现扰动后频率变化率超过第一阈值的情况下保证所述电网系统安全运行的第一安全惯量；
    确定在所述电网系统出现所述扰动后频率低于第二阈值的情况下保证所述电网系统安全运行的第二安全惯量；
    根据所述第一安全惯量和所述第二安全惯量，确定目标安全惯量，其中，所述目标安全惯量为保证所述电网系统安全运行的安全惯量下限值。
  2. 根据权利要求1所述的方法，其中，所述确定在电网系统出现扰动后频率变化率超过第一阈值的情况下保证所述电网系统安全运行的第一安全惯量，包括：
    获取所述电网系统的额定频率；
    确定所述电网系统的近扰动点的频率变化率；
    确定由于频率变化引起的负荷功率的变化量；
    根据所述额定频率、所述近扰动点的频率变化率和所述由于频率变化引起的负荷功率的变化量，确定所述第一安全惯量。
  3. 根据权利要求2所述的方法，其中，所述确定所述电网系统的近扰动点的频率变化率，包括：
    获取所述电网系统的惯量中心的频率变化率；
    确定所述近扰动点的频率变化率与所述惯量中心的频率变化率的比例关系；
    根据所述比例关系和所述惯量中心的频率变化率，确定所述近扰动点的频率变化率。
  4. 根据权利要求2所述的方法，其中，所述确定由于频率变化引起的负荷功率的变化量，包括：
    获取在所述扰动发生前所述电网系统中负荷的有功功率，以及负荷节点的电压；
    根据所述负荷的有功功率和所述负荷节点的电压，确定第一功率变化量，其中，所述第一功率变化量为由于电压变化引起的负荷功率的变化量；
    确定在所述扰动的影响下所述电网系统产生的超过第三阈值的功率变化量为第二功率变化量；
    确定所述由于频率变化引起的负荷功率的变化量为所述第一功率变化量与所述第二功率变化量的差。
  5. 根据权利要求1所述的方法，其中，所述确定在所述电网系统出现所述扰动后频率低于第二阈值的情况下保证所述电网系统安全运行的第二安全惯 量，包括：
    获取所述电网系统的额定下限频率；
    响应于所述电网系统出现所述扰动后频率为所述额定下限频率，确定保证所述电网系统安全运行的惯量为所述第二安全惯量。
  6. 根据权利要求5所述的方法，其中，所述响应于所述电网系统出现所述扰动后频率为所述额定下限频率，确定保证所述电网系统安全运行的惯量为所述第二安全惯量，包括：
    获取所述电网系统的额定频率、所述电网系统的阻尼系数、在所述扰动下所述电网系统的一次调频速率和一次调频动作时间；
    响应于所述电网系统出现所述扰动后频率为所述额定下限频率，根据所述电网系统的额定频率、所述电网系统的阻尼系数、在所述扰动下所述电网系统的一次调频速率和一次调频动作时间，确定保证所述电网系统安全运行的惯量为所述第二安全惯量。
  7. 根据权利要求1至6中任意一项所述的方法，其中，所述根据所述第一安全惯量和所述第二安全惯量，确定目标安全惯量，包括：
    确定所述第一安全惯量和所述第二安全惯量中的最大值为所述目标安全惯量。
  8. 一种电网系统的安全惯量确定装置，包括：
    第一确定模块，设置为确定在电网系统出现扰动后频率变化率超过第一阈值的情况下保证所述电网系统安全运行的第一安全惯量；
    第二确定模块，设置为确定在所述电网系统出现所述扰动后频率低于第二阈值的情况下保证所述电网系统安全运行的第二安全惯量；
    第三确定模块，设置为根据所述第一安全惯量和所述第二安全惯量，确定目标安全惯量，其中，所述目标安全惯量为保证所述电网系统安全运行的安全惯量下限值。
  9. 一种非易失性存储介质，所述非易失性存储介质包括存储的程序，其中，在所述程序运行时控制所述非易失性存储介质所在设备执行权利要求1至7中任意一项所述的电网系统的安全惯量确定方法。
  10. 一种计算机设备，包括：存储器和处理器，
    所述存储器存储有计算机程序；
    所述处理器，用于执行所述存储器中存储的计算机程序，所述计算机程序运行时使得所述处理器执行权利要求1至7中任意一项所述的电网系统的安全惯量确定方法。
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CN119834282A (zh) * 2025-01-07 2025-04-15 上海交通大学 船舶混合电站储能系统直流链路电容配置方法
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