CN116131278A - Power grid frequency safety online analysis method and device - Google Patents
Power grid frequency safety online analysis method and device Download PDFInfo
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- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
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Abstract
The application relates to the field of power systems, in particular to a method and a device for safely analyzing power grid frequency on line. The power grid frequency safety online analysis method comprises the steps of obtaining a system inertia adequacy; acquiring a calculation mode of the frequency change rate according to the inertia adequacy of the system; acquiring frequency safety influence factors according to a calculation mode of the frequency change speed; evaluating the inertia adequacy of the system, and acquiring an inertia adequacy evaluation result; judging whether a safe operation domain of the power grid frequency exists or not according to the frequency change rate and the frequency safety influence factors; and analyzing the frequency safety of the power grid in the current operation mode according to the inertia abundance evaluation result and the existence condition of the safety operation domain. The analysis method can effectively establish the online evaluation index of the frequency safety level of the power grid, provides the online evaluation method of the frequency safety level applicable to the high-duty ratio interconnected power grid of the new energy, simplifies the safety evaluation work and provides decision basis for the safe operation of the power grid.
Description
Technical Field
The application relates to the field of power systems, in particular to a method and a device for safely analyzing power grid frequency on line.
Background
Along with the continuous increase of the installation proportion of new energy, the inertia level of the system is rapidly reduced, and the method is an important technical means for solving the problem of power supply protection caused by the intermittence and randomness of new energy power generation and enhancing the interconnection and mutual supply of power grids. However, the power grid in China has the characteristic of 'strong and weak intersection', the large power grid is separated by direct current transmission, the rotational inertia is difficult to share, and the running mode of the new energy power system is complex and changeable, so that the inertia level of the power grid is difficult to evaluate and manage on line.
At present, the online evaluation of the inertia of the system is mainly obtained according to operation experience and system simulation, and theoretical support is lacked. The indexes such as frequency modulation standby, unsynchronized power generation permeability and the like can only be used for on-line frequency safety of a side surface representation system, and the on-line frequency safety quantitative evaluation of the system cannot be directly performed, so that the method is only suitable for being used as a reference and used for guiding the on-line frequency safety evaluation to be insufficient.
Disclosure of Invention
In view of the above, the application provides a method and a device for online analysis of power grid frequency safety, which solve or improve the technical problems that in the prior art, the online analysis and evaluation accuracy of the power grid system frequency is insufficient, and the power grid frequency safety is difficult to guarantee.
According to one aspect of the present application, there is provided a grid frequency security online analysis method, including: acquiring the inertia adequacy of a system, and acquiring a calculation mode of a frequency change rate according to the inertia adequacy of the system; acquiring frequency safety influence factors according to the calculation mode of the frequency change speed; evaluating the inertia adequacy of the system, and obtaining an inertia adequacy evaluation result; judging whether a safe operation domain of the power grid frequency exists or not according to the frequency change rate and the frequency safety influence factor; and analyzing the frequency safety of the power grid in the current operation mode according to the inertia adequacy assessment result and the existence condition of the safety operation domain.
In one possible implementation manner, the obtaining the equivalent inertia adequacy of the system includes: acquiring an equivalent inertia coefficient of the system and an inertia abundance reference; and carrying out per unit processing on the equivalent inertia coefficient of the system according to the inertia adequacy standard, and taking the processed equivalent inertia coefficient of the system as the inertia adequacy of the system.
In one possible implementation manner, the obtaining the equivalent inertia coefficient of the system includes: acquiring the rotation kinetic energy and the start-stop state of a generator set, the rotation kinetic energy and the start-stop state of a motor, and the equivalent rotation kinetic energy and the start-stop state of an electronic power supply; substituting the start-stop state of the rotational kinetic energy of the generator set, the rotational kinetic energy and the start-stop state of the motor, the equivalent rotational kinetic energy and the start-stop state of the power electronic power supply and the load of the system into a formula (I), and calculating the equivalent inertia coefficient of the system;
wherein ρ represents the system equivalent inertia coefficient,
representing the rotational kinetic energy of the generator set i +.>
Representing the rotational kinetic energy of motor j +.>
Representing the equivalent rotational kinetic energy, s, of an electric power type power supply k i 、s j 、s k Respectively representing the start-stop state of the generator, the motor and the power electronic power supply, wherein the value is shown as a calculation formula (II), L sys Representing the load size of the system +.>
In one possible implementation, the acquiring the load of the system includes: acquiring synchronous power output, power electronic power output and external power receiving power; and calculating the load of the system according to the synchronous power supply output, the power electronic power supply output and the external power receiving power.
In one possible implementation manner, the calculating manner of the frequency change rate according to the inertia adequacy of the system includes obtaining power impact, start-stop state of a power supply, load of the system and load of a motor; the rate of frequency change is calculated based on the power surge, the on-off state of the power supply, the load of the system, and the load of the motor.
In one possible implementation manner, the step of evaluating the inertia adequacy of the system to obtain an inertia adequacy evaluation result includes: acquiring the minimum inertia adequacy of the current regional power grid in a typical operation mode; comparing the system inertia adequacy with the minimum inertia adequacy, and when the system inertia adequacy is greater than or equal to the minimum inertia adequacy, the inertia adequacy assessment result is that the frequency safety margin is sufficient; and when the inertia adequacy of the system is smaller than the minimum inertia adequacy, the inertia adequacy assessment result is that the frequency safety margin is insufficient, and the current running mode of the power grid is adjusted.
In one possible implementation manner, the determining whether the safe operation domain of the grid frequency exists according to the frequency change rate and the frequency safety influence factor includes: obtaining the maximum power impact of the power grid in the current operation mode; acquiring the load inertia characteristic of the power grid in the current operation mode; acquiring the equivalent rotational kinetic energy requirement of a power supply according to the maximum power impact and the load inertia characteristic; acquiring a start-stop combination of a unit; judging whether a safe operation domain of the power grid frequency exists or not according to the start-stop combination of the unit and the equivalent rotational kinetic energy requirement of the power supply; when the start-stop combination of the unit meets the power supply equivalent rotation kinetic energy requirement, a safe operation domain of the power grid frequency exists, and when the start-stop combination of the unit does not meet the power supply equivalent rotation kinetic energy requirement, the safe operation domain of the power grid frequency does not exist.
In one possible implementation manner, the obtaining the maximum power impact in the current operation mode of the power grid includes: acquiring voltage impact and power impact of a power grid in a current operation mode; and obtaining the maximum impact power of the power grid in the current operation mode according to the voltage impact and the power impact of the power grid in the current operation mode.
In one possible implementation manner, the obtaining the load inertia characteristic of the current operation mode of the power grid includes: acquiring motor inertia and load of a power grid in a current operation mode; and acquiring the load inertia characteristic of the power grid in the current operation mode according to the motor inertia and the load size of the power grid in the current operation mode.
According to another aspect of the present application, there is also provided an on-line analysis device for grid frequency security, the on-line analysis device for grid frequency security including: the system inertia adequacy acquisition module is used for acquiring the system inertia adequacy; the frequency change rate calculation module is used for obtaining a calculation mode of the frequency change rate according to the inertia adequacy of the system; the frequency safety influence factor acquisition module is used for acquiring frequency safety influence factors according to the calculation mode of the frequency change speed; the inertia adequacy assessment result acquisition module is used for assessing the inertia adequacy of the system and acquiring an inertia adequacy assessment result; the safe operation domain judging module is used for judging whether a safe operation domain of the power grid frequency exists or not according to the frequency change rate and the frequency safety influence factors; and the power grid frequency safety analysis module is used for analyzing the power grid frequency safety in the current operation mode according to the inertia adequacy assessment result and the existence condition of the safety operation domain.
The application provides a method and a device for safely analyzing power grid frequency on line. The power grid frequency safety online analysis method specifically comprises the following steps: acquiring a system inertia adequacy; acquiring a calculation mode of the frequency change rate according to the inertia adequacy of the system; acquiring frequency safety influence factors according to a calculation mode of the frequency change speed; evaluating the inertia adequacy of the system, and acquiring an inertia adequacy evaluation result; judging whether a safe operation domain of the power grid frequency exists or not according to the frequency change rate and the frequency safety influence factor; and analyzing the frequency safety of the power grid in the current operation mode according to the inertia abundance evaluation result and the existence condition of the safety operation domain. The online analysis method for the frequency safety of the power grid can effectively establish online assessment indexes of the frequency safety level of the power grid, provides the online assessment method for the frequency safety level of the novel energy high-duty ratio interconnected power grid, simplifies the safety assessment work, reduces the required simulation calculation workload, provides the online assessment flow of the inertia adequacy of the power grid and the online analysis method for the safety operation domain, and provides decision basis for the safety operation of the power grid.
Drawings
Fig. 1 is a schematic flow chart of a method for online analysis of power grid frequency security according to an embodiment of the present application.
Fig. 2 is a schematic flow chart of a method for online analysis of power grid frequency security according to another embodiment of the present application.
Fig. 3 is a flow chart of a system inertia adequacy online evaluation method in a power grid frequency safety online analysis method according to another embodiment of the present application.
Fig. 4 is a flow chart of a method for determining a safe operation domain of a power grid frequency in a method for online analysis of power grid frequency safety according to another embodiment of the present application.
Fig. 5 is a schematic diagram showing a relationship between a power impact ratio, an inertia adequacy and rocofs in a power grid frequency safety online analysis method according to another embodiment of the present application.
Fig. 6 is a flow chart of an online evaluation method of a power grid safety operation domain in a power grid frequency safety online analysis method according to another embodiment of the present application.
Fig. 7 is a schematic diagram of a grid frequency security operation domain in a grid frequency security online analysis method according to another embodiment of the present application.
Fig. 8 is a schematic structural diagram of an improved WSCC9 node system in a simulation verification process according to another embodiment of the present application.
Fig. 9 is a graph showing RoCoF variation of a modified WSCC9 node system after power surge during simulated verification provided by another embodiment of the present application.
Fig. 10 is a graph showing RoCoF a system after a link failure in a simulation verification process according to another embodiment of the present application.
Fig. 11 is a graph showing the effect of motor load inertia on rocofs during a simulation verification process provided in another embodiment of the present application.
Fig. 12 is a graph showing frequency variation characteristics of different operation modes in a simulation verification process according to another embodiment of the present application.
Fig. 13 is a block diagram of an electronic device according to an embodiment of the present application.
Detailed Description
In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise. All directional indications (such as up, down, left, right, front, back, top, bottom … …) in the embodiments of the present application are merely used to explain the relative positional relationship, movement, etc. between the components in a particular gesture (as shown in the drawings), and if the particular gesture changes, the directional indication changes accordingly. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may include other steps or elements not listed or inherent to such process, method, article, or apparatus.
Furthermore, references herein to "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.
The applicant further analyzes the reasons that the safety of the power grid is difficult to ensure, and knows that the frequency online analysis and evaluation accuracy of the power grid system in the prior art is not enough:
along with the continuous increase of the installation proportion of new energy, the inertia level of the system is rapidly reduced, and the method is an important technical means for solving the problem of power supply protection caused by the intermittence and randomness of new energy power generation and enhancing the interconnection and mutual supply of power grids. However, the power grid in China has the characteristic of 'strong and weak intersection', the large power grid is separated by direct current transmission, the rotational inertia is difficult to share, and the running mode of the new energy power system is complex and changeable, so that the inertia level of the power grid is difficult to evaluate and manage on line.
The frequency safety problem research of the new energy high-duty ratio power grid mainly expands around aspects of system response characteristics, system inertia evaluation, stability analysis, control and the like. The system inertia is an important index for representing the capability of the power grid for resisting frequency change, and is also a basis for researching the response characteristic of the system and formulating a stable control strategy, and three frequency safety indexes of the frequency change rate (rate of change of frequency, roCoF), the transient frequency deviation and the steady-state frequency deviation of the power grid are all related to the system inertia level. The prior art defines the generalized inertia of the power system from the angles of synchronous and asynchronous rotary inertia, electromagnetic coupling equivalent inertia and virtual inertia, analyzes the supporting effect of a demand side on the system inertia, provides an online quick estimation method for the rotary inertia characteristics of the source load two sides based on a disturbance method, provides decision basis for the generation strategy formulation and the delivery quota approval of the system, and also provides a foundation for the evaluation of the frequency safety level of the system.
At present, the online evaluation of the inertia of the system is mainly obtained according to operation experience and system simulation, and theoretical support is lacked. The indexes such as frequency modulation standby, unsynchronized power generation permeability and the like can only be used for on-line frequency safety of a side surface representation system, and the on-line frequency safety quantitative evaluation of the system cannot be directly performed, so that the method is only suitable for being used as a reference and used for guiding the on-line frequency safety evaluation to be insufficient.
Aiming at the problems, the power grid inertia composition is comprehensively considered, a power grid inertia level reference standard is established, inertia adequacy index and RoCoF index of the power grid are proposed according to the power source inertia, load inertia and exchange power of the power grid, influence factors influencing the frequency safety of a system are analyzed, a frequency safety level online evaluation method and a frequency safety operation domain analysis method considering RoCoF constraint are proposed, decision basis is provided for frequency safety online evaluation and safety management and control of the power grid, and the method has important significance for the safe operation of the power grid.
Therefore, the application provides a method and a device for safely analyzing the frequency of a power grid on line. The power grid frequency safety online analysis method specifically comprises the following steps: acquiring a system inertia adequacy; acquiring a calculation mode of the frequency change rate according to the inertia adequacy of the system; acquiring frequency safety influence factors according to a calculation mode of the frequency change speed; evaluating the inertia adequacy of the system, and acquiring an inertia adequacy evaluation result; judging whether a safe operation domain of the power grid frequency exists or not according to the frequency change rate and the frequency safety influence factor; and analyzing the frequency safety of the power grid in the current operation mode according to the inertia abundance evaluation result and the existence condition of the safety operation domain. The online analysis method for the frequency safety of the power grid can effectively establish online assessment indexes of the frequency safety level of the power grid, provides the online assessment method for the frequency safety level of the novel energy high-duty ratio interconnected power grid, simplifies the safety assessment work, reduces the required simulation calculation workload, provides the online assessment flow of the inertia adequacy of the power grid and the online analysis method for the safety operation domain, and provides decision basis for the safety operation of the power grid.
The following description of the technical solutions in the embodiments of the present application will be made clearly and completely with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.
Fig. 1 is a schematic flow chart of a method for online analysis of power grid frequency security according to an embodiment of the present application. As shown in fig. 1, the method for online analysis of the frequency safety of the power grid specifically includes the following steps:
step 100: and obtaining the inertia adequacy of the system.
The system inertia represents the degree of resistance to the change of the system state (frequency), and covers all factors for inhibiting the change of the frequency before the speed regulation system acts; the adequacy is used to represent steady state performance of the power system; the system inertia adequacy is a concept defined in the application. Since the frequency safety level of the power system is closely related to the abundance level of the (equivalent) rotational inertia of the system, which can be expressed as the sum of the total kinetic energy of all the rotating elements in the network and the equivalent kinetic energy of the power electronic type power supply.
Step 200: and acquiring a calculation mode of the frequency change rate according to the inertia adequacy of the system.
The rate of change of the frequency of the system (RoCoF rate of change of frequency) is a technical indicator directly related to the level of inertia of the system. By the conversion of the system inertia adequacy and the combination of the system power impact, the initial running frequency and the like, the calculation mode of the evaluation rate change rate can be obtained, so that the determination of the system inertia level can be more effectively carried out.
Step 300: and acquiring frequency safety influence factors according to the calculation mode of the frequency change speed.
The frequency safety influencing factors include, but are not limited to, fault impact, motor inertia influence, external exchange power influence and the like, which are factors influencing the frequency change of the system, and the safety of the power grid frequency can be more effectively evaluated and analyzed according to the factors, so that the reliability of the power grid operation process is ensured.
Step 400: and (5) evaluating the inertia adequacy of the system, and obtaining an inertia adequacy evaluation result.
The inertia adequacy assessment result is a frequency safety analysis result obtained after online assessment of the inertia adequacy of the system, such as sufficiency or insufficiency of the frequency safety margin under the current operation mode. The evaluation mode is suitable for a new energy power system with load characteristics, a power generation mode and frequent external exchange power changes, and can obviously reduce the on-line evaluation workload.
Step 500: and judging whether a safe operation domain of the power grid frequency exists or not according to the frequency change rate and the frequency safety influence factors.
The safe operation domain of the power grid frequency is an area in which the whole power grid system can safely and stably operate, and the relative relation between the system operation point and the boundary can provide safety margin and optimal control information, so that the online real-time safety monitoring, defense and control of the power system are more scientific and effective.
Step 600: and analyzing the frequency safety of the power grid in the current operation mode according to the inertia abundance evaluation result and the existence condition of the safety operation domain.
The method is simple, clear and accurate in calculation, can provide quantitative indexes for power grid frequency safety analysis, and remarkably improves power grid frequency safety analysis efficiency.
In one possible implementation, as shown in fig. 2, the step 100 (to obtain the inertia adequacy of the system) may further include the steps of:
Step 110: and acquiring an equivalent inertia coefficient of the system and an inertia abundance reference.
The system equivalent inertia coefficient is a coefficient set by combining various factors such as the inertia supporting capacity of a synchronous power supply, a motor load and an electric power electronic power supply, and the inertia adequacy reference is reference data for carrying out per unit processing on the system equivalent inertia coefficient.
Step 120: and carrying out per unit processing on the equivalent inertia coefficient of the system according to the inertia adequacy standard, and taking the processed equivalent inertia coefficient of the system as the inertia adequacy of the system.
The system inertia adequacy is obtained by utilizing the system equivalent inertia coefficient integrating multiple factors, and is used as an index for online evaluation of the frequency safety level of the power grid, so that the evaluation flow is simplified, the workload of simulation calculation is reduced, and a decision basis is provided for the safe operation of the power grid.
Specifically, in an embodiment of the present application, step 110 (to obtain the equivalent inertia coefficient of the system and the inertia adequacy reference) may include the following steps:
step 111: the method comprises the steps of obtaining the rotation kinetic energy and the start-stop state of a generator set, the rotation kinetic energy and the start-stop state of a motor, the equivalent rotation kinetic energy and the start-stop state of an electronic power supply and the load of a system.
Step 112: substituting the starting and stopping state of the rotational kinetic energy of the generator set, the rotational kinetic energy and starting and stopping state of the motor, the equivalent rotational kinetic energy and starting and stopping state of the power electronic power supply and the load of the system into a formula (I), and calculating the equivalent inertia coefficient of the system.
Wherein ρ represents the system equivalent inertia coefficient,
representing the rotational kinetic energy of the generator set i +.>
Representing the rotational kinetic energy of motor j +.>
Representing the equivalent rotational kinetic energy, s, of an electric power type power supply k i 、s j 、s k Respectively represents the start-stop state of the generator, the motor and the power electronic type power supplyThe value of the product is shown as a calculation formula (II), L sys Indicating the magnitude of the load on the system,
further, the step 111 (obtaining the rotational kinetic energy and the start-stop state of the generator set, the rotational kinetic energy and the start-stop state of the motor, the equivalent rotational kinetic energy and the start-stop state of the power electronic power supply, and the load of the system) of "obtaining the load of the system" may specifically include the following steps:
step 1110: and acquiring the output of the synchronous power supply, the output of the power electronic power supply and the external power.
Step 1111: and calculating the load of the system according to the synchronous power output, the power electronic power output and the external power.
When the network loss is not counted, the load of the system can be expressed as the sum of the output of the synchronous power supply, the output of the power electronic power supply and the external power supply in the system, and the sum is specifically expressed as a formula (III),
Wherein L is sys Indicating the magnitude of the load on the system,
representing the rated capacity of the synchronous power supply i +.>
Represents the rated capacity of the power electronic power supply k, beta represents the output coefficient of the synchronous power supply, and P in Representing the external power received by the system.
In addition, the sum of rotational kinetic energy of the motor in the formula (one) can be obtained by the following formula (four),
wherein eta is the motor load proportion, H m Is a uniform inertia time constant of the motor.
Substituting the formula (III) and the formula (IV) into the formula (I) can calculate and obtain a calculation formula (V) of the equivalent inertia coefficient of the system with the load inertia and the external influence.
According to the calculation formula (five) and the inertia adequacy standard, carrying out per unit processing on the equivalent inertia coefficient of the system to obtain a calculation formula (six) of the equivalent inertia adequacy of the system, wherein the calculation formula (six) is as follows:
wherein ρ is B As an inertia abundance reference ρ * And is sufficient for the inertia of the system.
Inertia adequacy reference ρ B The calculation mode of (c) is shown as a formula (seventh),
it will be appreciated that when ρ * When=1, the inertia adequacy of the system is equivalent to ρ B At this time, the inertia adequacy of the system is equivalent to the running state B, namely, the external exchange power of the system is zero, all synchronous power supplies operate at rated power, all electric power type power supplies are stopped, and the load does not contain the running state of the rotating element. When ρ is * <1, the inertia adequacy of the system is smaller than the running state B, when ρ * >1, the inertia adequacy of the system is greater than the operating state B.
The following is an example of inertia adequacy criteria for a typical provincial grid, and a specific inertia adequacy criteria is shown in table 1.
TABLE 1 inertia adequacy reference for a typical provincial grid
In table 1, a power grid a is a typical ac power grid, a power grid b is a typical ac power grid, and a power grid c is a power grid with abundant water and electricity.
When the inertia influence of the power electronic type power supply and the motor load is not considered, the hydropower phase in the power grid shown in the table 1 is operated, the thermal power is operated in the minimum technical output state (30% rated power), and the inertia adequacy of a typical provincial power grid (maximum) system is obtained as shown in the table 2.
Table 2 inertia adequacy of a typical provincial grid
In another possible implementation, as shown in fig. 2, step 200 (a calculation method for obtaining a frequency change rate according to a system inertia adequacy) may further include the following steps:
step 210: the power surge, the start-stop state of the power supply, the load of the system, and the load of the motor are obtained.
Step 220: the rate of change of frequency is calculated based on the power surge, the on-off state of the power supply, the load of the system, and the load of the motor.
The rate of change of the frequency of the system is a technical indicator directly related to the level of inertia of the system. Let the power impact of the system be delta P fault The rocofafter the system is disturbed is shown in formula (eight),
wherein f 0 Representing the initial operating frequency of the system, bringing the formula (III) and the calculation formula (five) into the formula (eight), obtaining the RocOF of the system as shown in the formula (nine),
further deriving the available formula (ten) is shown below,
as can be seen from the formula (nine), the frequency change rate of the system is commonly affected by the power surge, the power on-off state, the system load level, the motor load, and the like. The rocofs after system disturbance can be reduced by reducing the power impact of faults, turning on a power supply with (equivalent) rotational inertia, and raising the inertia level of the load.
It should be noted that, for the above factors that can reduce the frequency change rate after the system is disturbed, the present application may provide the following analysis:
first, for a failed power surge, it can be seen from equation (nine) that in order to make the system disturbed rocif below the maximum safe rate of frequency change τ 0 The maximum power impact that the system can withstand should meet the following limitations:
as can be seen from the formula (eleven), the maximum power impact that the system can bear is related to the start-stop state of the unit in the network, the motor load characteristic and the maximum allowable RoCoF of the system.
Ignoring the influence of the initial frequency change of disturbance on the frequency sensitive load, the power impact of the system can be decomposed into direct power impact delta P P And voltage change power surge Δp U The method comprises the following steps:
ΔP fault ＝ΔP P +ΔP U (formula twelve)
Direct power surge Δp P The power shortage is caused by the direct fault, such as the power shortage of the receiving end caused by line disconnection, machine failure, direct current locking and the like. When the voltage changes, the voltage sensitive load can be expressed as:
in the formula (thirteen), P 0 A load value representing normal operation at rated voltage; k (k) 1 、k 2 、k 3 The ratio of the constant impedance load, the constant current load and the constant power load is represented as 1; u (U) 0 Representing the normal operating voltage without disturbance; Δu represents the amount of voltage disturbance.
As can be seen from the formula (thirteen), the power surge caused by the instantaneous voltage change is:
therefore, when considering the fault impact bearing capacity of the system, the direct power deficiency caused by the fault and the power disturbance caused by the voltage change should be considered at the same time.
Second, the impact of external switching power on the system can be analyzed as follows:
the above expression (five) is decomposed as follows, and:
wherein ρ is s 、ρ l The power source side inertia and the load side inertia, respectively. When the system exchanges power P in In the absence of correlation with the maximum power surge that the system may be subjected to, as shown in the calculation formula (fifteen), the load inertia ρ is calculated for the operation mode in which the load size and the load characteristics are determined l For a given value, the power supply rotational inertia ρ is set so that the total inertia ρ of the system (where ρ is different from ρ in equation one) meets the frequency safety requirement s Is the main controllable factor. Therefore, under the limit of meeting the minimum adequacy index, when the in-area unit which does not provide rotational inertia is stopped and the synchronous unit in the starting state is in the state of minimum technical output, the external power receiving can be maximized, if the external exchange power exceeds the value, the frequency safety of the system is at risk.
When the system exchanges power P in With the maximum power surge Δp that the system may withstand fault When equal (e.g., dc blocking), the maximum external capacitance of the system is obtained by equation (ten):
again, as for the motor inertia, from the calculation formula (fifteen), it is known that the load inertia ρ in the same system l And power supply inertia ρ s The ratio of (2) is:
in the power grid simulation of China, a typical load model of 'constant impedance+motor' is mostly adopted, the motor load proportion of each provincial power grid is about 30% -70%, and the uniform inertia coefficient of the load model is 2s. When the equivalent inertia of the power electronic power source is not considered in a typical manner according to the formula (seventeen), the ratio of the load inertia to the power source inertia of the typical provincial power grid is shown in table 3.
TABLE 3 ratio of source to inertia for a typical provincial grid
As shown in Table 3, the motor load provides a rotational inertia of about 15% -40% of the power inertia. In the frequency safety analysis of the power grid, it is necessary to consider the influence of the rotational inertia of the load of the power grid, for example, the load inertia is ignored, which causes a larger deviation. In practice, the load inertia of the power grid can be estimated through a statistical method and a disturbance method.
At the most time, for the displacement relation between inertia and output in the system, the equivalent inertia coefficient of the regional power grid is shown as a calculation formula (fifteen), and the equivalent inertia of the system comprises a power supply part rho s And a load portion ρ l In both aspects ρ s And ρ l The equivalent replacement is not changedThe magnitude of the total inertia ρ of the system.
Similarly, as shown in the formula (III), when the start-stop state of the power supply in the regional power grid is determined and the (equivalent) rotational inertia of the power supply does not change along with the output level, the total power generation output of the power supply and the external power receiving level are replaced by equal amounts, so that the inertia level of the system is not changed. The equivalent displacement relation of the output power is also existed between the power supplies in the regional power grid, and only the power generation plan is changed without changing the inertia of the system.
Specifically, in another embodiment of the present application, as shown in fig. 2, step 400 (to evaluate the inertia adequacy of the system and obtain the evaluation result of the inertia adequacy) may specifically include the following steps:
Step 410: and obtaining the minimum inertia adequacy of the current regional power grid in a typical operation mode.
The energy power system has the advantages of multiple operation modes, rapid change, large workload, poor timeliness and great difficulty in real-time evaluation of the inertia abundance level of the system in an online simulation mode.
From the analysis, the rotational inertia and the generated power have replaceable characteristics, and the inertia adequacy ρ is * The same different modes of operation have the same level of inertia abundance. When the power grid structure is not changed significantly, checking the typical operation mode of a power grid in a certain area to obtain the minimum safety inertia adequacy level
Has universal applicability to other operation modes.
Step 420: comparing the inertia adequacy of the system with the minimum inertia adequacy, and when the inertia adequacy of the system is larger than or equal to the minimum inertia adequacy, the inertia adequacy assessment result is that the frequency safety margin is sufficient.
Step 430: when the inertia adequacy of the system is smaller than the minimum inertia adequacy, the inertia adequacy assessment result is that the frequency safety margin is insufficient, and the current running mode of the power grid is adjusted.
Fig. 3 is a schematic diagram of a system inertia adequacy online evaluation flow in a method for online analysis of power grid frequency safety according to another embodiment of the present application. As shown in FIG. 3, the system inertia adequacy assessment may be performed in an "off-line test+on-line comparison" manner as shown. The evaluation mode is suitable for a new energy power system with load characteristics, a power generation mode and frequent external exchange power changes, and can obviously reduce the on-line evaluation workload. Meanwhile, when the evaluation result is that the frequency safety margin of the system is insufficient, the running mode at the current moment can be timely adjusted, so that the normal running of the power system is ensured, and the probability of safety accidents is reduced.
In a possible implementation manner, fig. 4 is a flow chart of a method for determining a safe operation domain of a power grid frequency in a method for online analysis of power grid frequency safety according to another embodiment of the present application. As shown in fig. 4, step 500 (determining whether a safe operating domain of the grid frequency exists according to the rate of change of the frequency and the frequency safety influencing factor) may include the steps of:
step 510: and obtaining the maximum power impact of the power grid in the current operation mode.
Step 520: and acquiring the load inertia characteristic of the power grid in the current operation mode.
Step 530: and obtaining the equivalent rotational kinetic energy requirement of the power supply according to the maximum power impact and the load inertia characteristics.
Step 540: and obtaining a start-stop combination of the unit.
Step 550: and judging whether a safe operation domain of the power grid frequency exists or not according to the start-stop combination of the unit and the power supply equivalent rotation kinetic energy requirement.
When the start-stop combination of the unit meets the power supply equivalent rotation kinetic energy requirement, a safe operation domain of the power grid frequency exists, and when the start-stop combination of the unit does not meet the power supply equivalent rotation kinetic energy requirement, the safe operation domain of the power grid frequency does not exist.
In order to analyze the safe operation domain of the power grid system, the proportion of the power impact received by the regional power grid to the total load of the regional power grid is as follows:
Substituting equation (eighteen) into equation (eight) to obtain:
it follows that for a regional power grid, the power surge ratio Δp' fault Inertia adequacy ρ * The correlation between the power impact ratio and the inertia adequacy and the rocofs in the power grid frequency safety online analysis method according to another embodiment of the present application is shown in the formula (nineteenth) and fig. 5, wherein fig. 5 is a schematic diagram of the correlation between the power impact ratio and the inertia adequacy and the rocofs.
For an actual grid, the maximum rocofallowed by the system is typically set to some fixed value. The operation mode of the regional power grid is changed at the moment, and the load size, the motor inertia size and the possible maximum power impact are changed along with the change moment of the operation mode. The power supply start-stop state, the power generation plan and the external power receiving size become controllable factors for guaranteeing the security of the system RoCoF.
In order to maintain a certain frequency safety margin for the operation mode of the system, the safe operation feasible region of the power grid can be evaluated on line in combination with the analysis flow shown in step 500.
Specifically, in an embodiment of the present application, step 510 (to obtain the maximum power impact in the current operation mode of the power grid) may include the following steps:
step 511: and acquiring voltage impact and power impact of the power grid in the current operation mode.
Step 512: and obtaining the maximum impact power of the power grid in the current operation mode according to the voltage impact and the power impact of the power grid in the current operation mode.
Meanwhile, step 520 (to obtain the load inertia characteristics of the current operation mode of the power grid) may include the following steps:
step 521: and acquiring the motor inertia and the load of the power grid in the current operation mode.
Step 522: and acquiring the load inertia characteristic of the power grid in the current operation mode according to the motor inertia and the load size of the power grid in the current operation mode.
By evaluating and monitoring factors such as voltage supply, power impact, motor inertia and load size in the instant operation mode, the maximum power impact and load inertia characteristics in the operation mode can be obtained, and the frequency change constraint tau < tau of the power grid is considered 0 The equivalent rotational kinetic energy requirement of the power supply can be obtained.
In the running mode, if the start-stop combination of the unit cannot meet the minimum safe rotation kinetic energy requirement, a frequency safe running domain does not exist, the running mode is required to be adjusted, and partial load is removed; if the start-stop combination of the unit can obtain rotational kinetic energy larger than the minimum safety requirement, a frequency safety operation domain exists. Fig. 6 is a flow chart of an online evaluation method of a power grid safety operation domain in a power grid frequency safety online analysis method according to another embodiment of the present application. Fig. 7 is a schematic diagram of a grid frequency security operation domain in a grid frequency security online analysis method according to another embodiment of the present application. The safe combination mode of the power supply start-stop state, the unit power generation plan and the external power supply power forms a power grid frequency safe operation domain as shown in figure 7.
The start-stop state of the machine set in the network determines the equivalent rotation kinetic energy of the power supply, the sum of the power generation amount in the network and the power receiving outside is approximately equal to the load of the system, and the power generation amount in the network is limited by the maximum and minimum technical output of the started machine set. The actual start-stop state, the power generation plan and the external power receiving state of the unit can be determined in the frequency safety operation domain by considering other constraints such as economy and the like.
In addition, the applicant carries out simulation verification on the accuracy of the related indexes on the online analysis method for the frequency safety of the power grid, which is sufficient for explaining the accuracy of the online analysis method.
Fig. 8 is a schematic structural diagram of an improved WSCC9 node system in a simulation verification process according to another embodiment of the present application. The improved WSCC9 node example is built based on PSD-BPA software to carry out simulation verification, the source charge condition of the example is shown in table 4, and the operation state is shown in fig. 8 as a basis. The system S1 and the 9 node computer communicate through the power electronic type equipment, the rotational inertia support is not provided, the photovoltaic power supply does not provide equivalent rotational inertia, and the frequency modulation system of the unit is not considered. The load model of the mode a is a constant impedance+motor model, and the motor ratio is 60%.
Table 4 improved WSCC9 node system configuration
Theoretical calculation: the equivalent inertia coefficient ρ of the example in the mode a is 6.813s calculated by the equation (5). The inertia adequacy criterion of the example calculated by the formula (7) is 4.865s, and the inertia adequacy index calculated by the formula (6) is 1.4. When the system is impacted by 10MW power according to the calculation of the formula (9), the frequency dropping speed is 0.04696Hz/s.
Fig. 9 is a graph showing RoCoF variation of a modified WSCC9 node system after power surge during simulated verification provided by another embodiment of the present application. To test the evaluation effect of the frequency safety index, the simulation shows the mode a, and the frequency change curve of the system after the system is impacted by 10MW power at the moment of 1s is shown in fig. 9.
As can be seen from the simulation curves of FIG. 9, the system drops in frequency by 0.04653Hz at 1s after the fault, and the maximum frequency drop speed of the system is slightly more than 0.04653Hz/s in consideration of the frequency adjustment effect of the load. The system frequency drop theoretical speed is 0.04696Hz/s by the calculation of the formula (nine), the difference value between the theoretical calculation result and the simulation result is smaller than 0.00043Hz/s, and the calculation error of the formula (nine) is smaller than 1.1%. The frequency falling speed can be accurately calculated by the frequency safety evaluation index.
Fig. 10 is a graph showing RoCoF a system after a link failure in a simulation verification process according to another embodiment of the present application. The maximum value of the RoCoF allowed by the system is set to be 0.500Hz/s, and the maximum external power is calculated to be 109.1MW according to a formula (sixteen). And keeping the G1 and G2 started, and carrying out external power supply at 109.1MW, wherein the simulation shows that when the interconnection line fault occurs at the moment of 1s, the frequency change of the system is shown in figure 10.
The frequency drop after the fault is about 0.487Hz in 1s (namely 2 s), the frequency drop speed after the fault is greater than 0.487Hz/s in consideration of the regulation effect of the load, and the simulation result is different from the set value of 0.500Hz by less than 2.6 percent.
Under different rocofs, the calculated value and simulation result pairs of the maximum external power receiving capacity of the system are shown in table 5, and the error under the three rocofs is between 2.2% and 4.0%, which indicates that equation (16) can calculate the external power receiving capacity of the system under the maximum rocofs after being disturbed more accurately.
Comparison of calculated and simulated values for maximum external power to Table 5 System
Calculating to obtain the equivalent inertia coefficient rho of the power supply in the mode a by calculation (fifteen) s 5.556s, load equivalent inertia coefficient ρ l For 1.200s, the load providing inertia accounts for 17.8% of the equivalent inertia of the system.
Fig. 11 is a graph showing the effect of motor load inertia on rocofs during a simulation verification process provided in another embodiment of the present application. In mode a, the RoCoF curve of the system that considers and ignores the effect of motor inertia when the simulation system is subjected to the same power impact is shown in fig. 10. As can be seen from fig. 11, the rocif of the system is significantly higher than considering the motor load inertia, regardless of the influence of the motor inertia. The motor inertia is an important component of the equivalent inertia of the system, and neglecting the influence of the motor inertia can cause inaccurate evaluation of the frequency characteristics of the power grid, so that the evaluation of the operation mode is too conservative.
In order to test the replacement characteristics of the equivalent inertia and the power supply output, the basic mode a is taken as a reference, the equivalent inertia adequacy rho is kept to be 1.4 unchanged, and the rotational kinetic energy and the power generation output are subjected to replacement adjustment, so that b, c, d, e four operation modes are formed. And simulating the 5 operation modes, and analyzing the frequency change characteristics of the system under the same power impact under different operation modes. The configuration of the 5 operation modes is shown in table 6, and fig. 12 is a frequency variation characteristic diagram of the different operation modes in the simulation verification process according to another embodiment of the present application. The frequency variation curve is shown in fig. 12.
TABLE 6 System parameters for different modes of operation
As shown in table 6, compared with the mode a, the mode b increases the load moment of inertia and reduces the inertia of the thermal power generating unit G1; the load rotation inertia is increased in the mode c, and the inertia of all thermal power units is reduced; the power generation amounts of the two thermal power plants are readjusted in the mode d; mode e reduces the generated energy of the thermal power and increases the external power.
As shown in fig. 12, when the mode a, b, c, d suffers the same power impact fault, the frequency drop curves are basically the same, all are 0.04653Hz/s, the initial drop speed of the mode e is the same, the drop depth is slightly different from the initial drop speed, and the maximum difference is not more than 3.2%.
As can be seen from the comparison of the modes a, b and c, the source-charge inertia of the system has a displacement relationship, and the frequency characteristic of the system is unchanged when the total inertia is kept unchanged. As can be seen from the comparison of the modes a, d and e, when the equivalent rotational inertia is unchanged, the power supply in the network and the power generation in the network and the power receiving from outside have displacement relations. Simulation results show that the equivalent inertia coefficient is the same in the operation mode, the frequency change characteristics after power impact are basically the same, and the accuracy of the calculation formula (five) and the formula (nine) is verified on the side face.
Therefore, the system inertia adequacy index of the interconnected power grid is defined by considering the system starting mode, the output plan, the load inertia and the external power receiving level, the system rocofcalculation method is obtained, the analysis method of the safe operation domain and the external power receiving capacity calculation method are provided, the technical index and the evaluation basis are provided for the frequency safety on-line analysis, and the accuracy of the provided index is checked through mutual verification of theory and simulation. The method is simple and clear, the calculation is accurate, the quantitative index of the power grid frequency safety analysis can be provided, and the power grid frequency safety analysis efficiency is remarkably improved.
According to a second aspect of the present application, the present application further provides a grid frequency security online analysis device, the grid frequency security online analysis device comprising: the system comprises a system inertia adequacy acquisition module, a frequency change rate calculation module, a frequency safety influence factor acquisition module, an inertia adequacy assessment result acquisition module, a safety operation domain judgment module and a power grid frequency safety analysis module. The system inertia adequacy acquisition module is used for acquiring the system inertia adequacy; the frequency change rate calculation module is used for obtaining a calculation mode of the frequency change rate according to the inertia adequacy of the system; the frequency safety influence factor acquisition module is used for acquiring frequency safety influence factors according to the calculation mode of the frequency change speed; the inertia adequacy assessment result acquisition module is used for assessing the inertia adequacy of the system and acquiring an inertia adequacy assessment result; the safe operation domain judging module is used for judging whether a safe operation domain of the power grid frequency exists or not according to the frequency change rate and the frequency safety influence factors; the power grid frequency safety analysis module is used for analyzing the power grid frequency safety in the current operation mode according to the inertia adequacy assessment result and the existence condition of the safety operation domain.
The above-mentioned online analysis device for frequency safety of electric network is used for applying the above-mentioned online analysis method for frequency safety of electric network, its advantage produced is the same as above-mentioned method, will not be repeated here.
Next, an electronic device according to an embodiment of the present application is described with reference to fig. 13.
Fig. 13 illustrates a block diagram of an electronic device according to an embodiment of the present application.
As shown in fig. 13, the electronic device 10 includes one or more processors 11 and a memory 12.
The processor 11 may be a Central Processing Unit (CPU) or other form of processing unit having data processing and/or instruction execution capabilities, and may control other components in the electronic device 10 to perform desired functions.
Memory 12 may include one or more computer program products that may include various forms of computer-readable storage media, such as volatile memory and/or non-volatile memory. The volatile memory may include, for example, random Access Memory (RAM) and/or cache memory (cache), and the like. The non-volatile memory may include, for example, read Only Memory (ROM), hard disk, flash memory, and the like. On which one or more computer program instructions may be stored that may be executed by the processor 11 to implement the grid frequency security online analysis method and/or other desired functions of the various embodiments of the present application described above.
In one example, the electronic device 10 may further include: an input device 13 and an output device 14, which are interconnected by a bus system and/or other forms of connection mechanisms (not shown).
When the electronic device is a stand-alone device, the input means 13 may be a communication network connector for receiving the acquired input signals from the first device and the second device.
In addition, the input device 13 may also include, for example, a keyboard, a mouse, and the like.
The output device 14 may output various information to the outside, including the determined distance information, direction information, and the like. The output device 14 may include, for example, a display, speakers, a printer, and a communication network and remote output devices connected thereto, etc.
Of course, only some of the components of the electronic device 10 that are relevant to the present application are shown in fig. 13 for simplicity, components such as buses, input/output interfaces, and the like being omitted. In addition, the electronic device 10 may include any other suitable components depending on the particular application.
As a third aspect of the present application, there is provided a computer-readable storage medium storing a computer program for executing the steps of:
Acquiring a system inertia adequacy; acquiring a calculation mode of the frequency change rate according to the inertia adequacy of the system; acquiring frequency safety influence factors according to a calculation mode of the frequency change speed; evaluating the inertia adequacy of the system, and acquiring an inertia adequacy evaluation result; judging whether a safe operation domain of the power grid frequency exists or not according to the frequency change rate and the frequency safety influence factor; and analyzing the frequency safety of the power grid in the current operation mode according to the inertia abundance evaluation result and the existence condition of the safety operation domain.
In addition to the methods and apparatus described above, embodiments of the present application may also be a computer program product comprising computer program information which, when executed by a processor, causes the processor to perform the steps in the grid frequency security online analysis method according to various embodiments of the present application described in the present specification.
The computer program product may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computing device, partly on the user's device, as a stand-alone software package, partly on the user's computing device, partly on a remote computing device, or entirely on the remote computing device or server.
Furthermore, embodiments of the present application may also be a computer readable storage medium having stored thereon computer program information, which when executed by a processor, causes the processor to perform the steps in the grid frequency security online analysis method according to various embodiments of the present application.
A computer readable storage medium may employ any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium may include, for example, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or a combination of any of the foregoing. More specific examples (a non-exhaustive list) of the readable storage medium would include the following: an electrical connection having one or more wires, a portable disk, a hard disk, random Access Memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
The basic principles of the present application have been described above in connection with specific embodiments, however, it should be noted that the advantages, benefits, effects, etc. mentioned in the present application are merely examples and not limiting, and these advantages, benefits, effects, etc. are not to be considered as necessarily possessed by the various embodiments of the present application. Furthermore, the specific details disclosed herein are for purposes of illustration and understanding only, and are not intended to be limiting, as the application is not intended to be limited to the details disclosed herein as such.
The block diagrams of the devices, apparatuses, devices, systems referred to in this application are only illustrative examples and are not intended to require or imply that the connections, arrangements, configurations must be made in the manner shown in the block diagrams. As will be appreciated by one of skill in the art, the devices, apparatuses, devices, systems may be connected, arranged, configured in any manner. Words such as "including," "comprising," "having," and the like are words of openness and mean "including but not limited to," and are used interchangeably therewith. The terms "or" and "as used herein refer to and are used interchangeably with the term" and/or "unless the context clearly indicates otherwise. The term "such as" as used herein refers to, and is used interchangeably with, the phrase "such as, but not limited to.
It is also noted that in the apparatus, devices and methods of the present application, the components or steps may be disassembled and/or assembled. Such decomposition and/or recombination should be considered as equivalent to the present application.
Claims (10)
1. The utility model provides a safe online analysis method of power grid frequency, which is characterized by comprising the following steps:
acquiring a system inertia adequacy;
acquiring a calculation mode of a frequency change rate according to the inertia adequacy of the system;
Acquiring frequency safety influence factors according to the calculation mode of the frequency change speed;
evaluating the inertia adequacy of the system, and obtaining an inertia adequacy evaluation result; and
judging whether a safe operation domain of the power grid frequency exists or not according to the frequency change rate and the frequency safety influence factor;
and analyzing the frequency safety of the power grid in the current operation mode according to the inertia adequacy assessment result and the existence condition of the safety operation domain.
2. The method for online analysis of grid frequency security according to claim 1, wherein the obtaining the equivalent inertia adequacy of the system comprises:
acquiring an equivalent inertia coefficient of the system and an inertia abundance reference;
and carrying out per unit processing on the equivalent inertia coefficient of the system according to the inertia adequacy standard, and taking the processed equivalent inertia coefficient of the system as the inertia adequacy of the system.
3. The method for online analysis of power grid frequency security according to claim 2, wherein the obtaining the equivalent inertia coefficient of the system comprises:
acquiring the rotation kinetic energy and the start-stop state of a generator set, the rotation kinetic energy and the start-stop state of a motor, and the equivalent rotation kinetic energy and the start-stop state of an electronic power supply;
Substituting the start-stop state of the rotational kinetic energy of the generator set, the rotational kinetic energy and the start-stop state of the motor, the equivalent rotational kinetic energy and the start-stop state of the power electronic power supply and the load of the system into a formula (I), and calculating the equivalent inertia coefficient of the system;
wherein ρ represents the system equivalent inertia coefficient,
representing the rotational kinetic energy of the generator set i +.>
Representing the rotational kinetic energy of motor j +.>
Representing the equivalent rotational kinetic energy, s, of an electric power type power supply k i 、s j 、s k Respectively representing the start-stop state of the generator, the motor and the power electronic power supply, wherein the value is shown as a calculation formula (II), L sys Indicating the magnitude of the load on the system,
4. a grid frequency security online analysis method according to claim 3, wherein the acquiring the load of the system comprises:
acquiring synchronous power output, power electronic power output and external power receiving power;
and calculating the load of the system according to the synchronous power supply output, the power electronic power supply output and the external power receiving power.
5. The method for online analysis of power grid frequency safety according to claim 1, wherein the calculating method for obtaining the frequency change rate according to the system inertia adequacy comprises the following steps:
Acquiring power impact, start-stop state of a power supply, load of a system and load of a motor;
the rate of frequency change is calculated based on the power surge, the on-off state of the power supply, the load of the system, and the load of the motor.
6. The method for online analysis of grid frequency security according to claim 1, wherein the step of evaluating the system inertia adequacy to obtain an inertia adequacy evaluation result comprises:
acquiring the minimum inertia adequacy of the current regional power grid in a typical operation mode;
comparing the system inertia adequacy with the minimum inertia adequacy, and when the system inertia adequacy is greater than or equal to the minimum inertia adequacy, the inertia adequacy assessment result is that the frequency safety margin is sufficient;
and when the inertia adequacy of the system is smaller than the minimum inertia adequacy, the inertia adequacy assessment result is that the frequency safety margin is insufficient, and the current running mode of the power grid is adjusted.
7. The method for online analysis of power grid frequency safety according to claim 1, wherein the determining whether a safe operation domain of the power grid frequency exists according to the frequency change rate and the frequency safety influence factor comprises:
Obtaining the maximum power impact of the power grid in the current operation mode;
acquiring the load inertia characteristic of the power grid in the current operation mode;
acquiring the equivalent rotational kinetic energy requirement of a power supply according to the maximum power impact and the load inertia characteristic;
acquiring a start-stop combination of a unit; and
judging whether a safe operation domain of the power grid frequency exists or not according to the start-stop combination of the unit and the equivalent rotational kinetic energy requirement of the power supply;
when the start-stop combination of the unit meets the power supply equivalent rotation kinetic energy requirement, a safe operation domain of the power grid frequency exists, and when the start-stop combination of the unit does not meet the power supply equivalent rotation kinetic energy requirement, the safe operation domain of the power grid frequency does not exist.
8. The method for online analysis of power grid frequency security according to claim 7, wherein the obtaining the maximum power impact of the current operation mode of the power grid comprises:
acquiring voltage impact and power impact of a power grid in a current operation mode;
and obtaining the maximum impact power of the power grid in the current operation mode according to the voltage impact and the power impact of the power grid in the current operation mode.
9. The method for online analysis of power grid frequency security according to claim 7, wherein the obtaining the load inertia characteristic of the power grid in the current operation mode comprises:
Acquiring motor inertia and load of a power grid in a current operation mode;
and acquiring the load inertia characteristic of the power grid in the current operation mode according to the motor inertia and the load size of the power grid in the current operation mode.
10. A grid frequency security online analysis device, comprising:
the system inertia adequacy acquisition module is used for acquiring the system inertia adequacy; the frequency change rate calculation module is used for obtaining a calculation mode of the frequency change rate according to the inertia adequacy of the system; the frequency safety influence factor acquisition module is used for acquiring frequency safety influence factors according to the calculation mode of the frequency change speed; the inertia adequacy assessment result acquisition module is used for assessing the inertia adequacy of the system and acquiring an inertia adequacy assessment result; the safe operation domain judging module is used for judging whether a safe operation domain of the power grid frequency exists or not according to the frequency change rate and the frequency safety influence factors; and the power grid frequency safety analysis module is used for analyzing the power grid frequency safety in the current operation mode according to the inertia adequacy assessment result and the existence condition of the safety operation domain.
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| CN116706944B (en) * | 2023-08-07 | 2023-10-27 | 昆明理工大学 | Method for determining new energy permeability under frequency safety constraint |
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