Secondary frequency modulation control method considering distributed resource intermittency based on dynamic joint simulation framework of main and distribution networks

Abstract

The invention discloses a secondary frequency modulation control method considering distributed resource intermittency based on a main and distribution network dynamic joint simulation framework. The method comprises the following steps: establishing the main and distribution network dynamic joint simulation framework; monitoring the frequency of the main network in real time, and detecting whether the frequency deviates; if the frequency deviates, the system carries out primary frequency modulation spontaneously; after primary frequency modulation is finished, calculating the total secondary frequency modulation amount of the system; the control center controls the distribution proportion of the secondary frequency modulation in the main network traditional generator set and the distribution network distributed resources in real time according to the current available capacity of the distributed resources; and regulating and controlling the secondary frequency modulation of the distributed resources of different distribution networks and different distributed resource nodes of a single distribution network in real time according to the allowance of the distributed resources which can be used for the secondary frequency modulation. According to the method, on the basis of the dynamic joint simulation framework of the main and distribution networks, the intermittency of the distributed resources is fully considered, the utilization rate of the distributed resources is improved, the flexibility and effectiveness of the secondary frequency modulation process are improved, and the stability of a power distribution system is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of secondary frequency regulation control involving distributed resources, and specifically is a secondary frequency regulation control method considering the intermittency of distributed resources based on a dynamic joint simulation framework of a main and distribution network. Background Art

[0002] In traditional power systems, frequency stability mainly relies on large-scale thermal power generating units through primary, secondary and tertiary frequency regulation technologies. Among them, secondary frequency regulation (AGC, Automatic Generation Control) adjusts the output of the generator to restore the frequency deviation caused by load fluctuations or changes in power generation. However, in modern power grids, with the access of distributed resources, the frequency regulation of the power grid has become more complicated. This is because the intermittent output of distributed resources leads to an increase in the dynamics of the system's active power supply, and traditional generators cannot undertake the task of frequency regulation alone. The system urgently needs a secondary frequency regulation method that can coordinate the main distribution network and distributed resources.

[0003] At the same time, the complexity of power system operation has further increased. The dynamic characteristics of the main grid and distribution grid are no longer isolated, and the coupling relationship between them has become closer. In actual operation, the coordinated dispatch and control between the main and distribution grids have become the key to ensuring system stability. Existing secondary frequency regulation technologies often only consider the frequency control of the main grid, while ignoring the dynamic characteristics of the distribution grid and the potential of distributed resources, resulting in slow response speed and low efficiency of secondary frequency regulation, and may even cause system stability problems.

[0004] Based on the above problems, we designed a secondary frequency regulation control method based on the dynamic joint simulation framework of the main and distribution networks and considering the intermittent nature of distributed resources to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the intermittent output of distributed resources in the prior art leads to an increase in the dynamics of the system's active power supply, and traditional generator sets cannot undertake the frequency regulation task alone; the existing secondary frequency regulation technology often only considers the frequency control of the main network, but ignores the dynamic characteristics of the distribution network and the potential of distributed resources, resulting in a slow response speed and low efficiency of the secondary frequency regulation. For this reason, the present invention proposes a secondary frequency regulation control method based on the dynamic joint simulation framework of the main and distribution networks that considers the intermittent nature of distributed resources, giving full play to the flexibility and controllability of distributed resources and reducing dependence on traditional thermal power units. This control method will provide more efficient and stable secondary frequency regulation services for modern power grids containing a large number of distributed resources, ensuring the frequency stability and safe operation of the power grid.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A secondary frequency regulation control method considering the intermittency of distributed resources based on a dynamic joint simulation framework of a main distribution network comprises the following steps:

[0008] Step 1: Establish a dynamic joint simulation framework for the main and distribution networks;

[0009] Step 2: Monitor the main network frequency in real time to detect whether the frequency is deviated;

[0010] Step 3: If the frequency deviates, the system will automatically adjust the frequency;

[0011] Step 4: After the primary frequency modulation is completed, calculate the total amount of secondary frequency modulation of the system;

[0012] Step 5: The control center controls the allocation ratio of secondary frequency regulation between traditional generators in the main grid and distributed resources in the distribution network in real time according to the currently available capacity of distributed resources;

[0013] Step 6: According to the margin of distributed resources available for secondary frequency modulation, the secondary frequency modulation of different distribution network distributed resources and different distributed resource nodes of a single distribution network is regulated in real time.

[0014] Furthermore, step 1, establishing a dynamic joint simulation framework of the main and distribution networks includes:

[0015] The main network simulation tool andes and the distribution network simulation tool OpenDSS are integrated together through the HELICS simulation platform. The main network and the distribution network are dynamically interconnected using the time synchronization mechanism. The publish-subscribe mechanism is used to exchange information between the main network and the distribution network, reflecting the power flow distribution between the main and distribution networks, and realizing the construction of a dynamic joint simulation framework for the main and distribution networks.

[0016] Furthermore, in step 4, the method for calculating the total amount of secondary frequency modulation of the system in real time according to the PI control principle is:

[0017]

[0018] AGC total =-K P ACE-K I ∫ACE (2)

[0019] Among them, ACE is the area control error, B is the natural frequency response coefficient, Δf is the difference between the actual frequency value f and the frequency reference value f0; AGC total It is the total amount of secondary frequency modulation of the system calculated according to the PI control principle, K P is the proportional coefficient in the PI controller, K I is the integral term coefficient in the PI controller.

[0020] Furthermore, in step 5, the control center controls the allocation ratio of the secondary frequency regulation between the traditional generators in the main grid and the distributed resources in the distribution network in real time according to the currently available capacity of the distributed resources, as follows:

[0021] AGC total =AGC trans +AGC der (3)

[0022]

[0023] Where, AGC trans AGC is a secondary frequency modulation issued by the control center to the traditional units of the main grid. der is the total amount of secondary frequency modulation issued by the control center to the distributed resources of the distribution network; α is the proportion of the secondary frequency modulation of distributed resources in the total secondary frequency modulation, which is adjusted according to the available capacity of the current distributed resources; P der is the total power of distributed resources, is the upper limit of the total power of distributed resources;

[0024] When the available capacity of distributed resources is sufficient, the distributed resources are used as the main object of secondary frequency regulation, and the traditional generators in the main grid are used as auxiliary and backup frequency regulation resources;

[0025] When the available capacity of distributed resources is insufficient, the traditional generators in the main grid are used as the main objects of secondary frequency regulation, and the distributed resources are used as auxiliary and backup frequency regulation resources;

[0026] In extreme cases, there is no available capacity in distributed resources, and only secondary frequency regulation is performed on traditional generators in the main grid.

[0027] Furthermore, in step 6, according to the capacity of the distributed resources available for secondary frequency modulation, the control center adjusts the secondary frequency modulation of the distributed resources of different distribution networks in real time, using the following formula and restriction conditions:

[0028]

[0029] AGC der，i =ω i AGC der (7)

[0030]

[0031] Where, AGC der，i is the secondary frequency modulation issued by the control center to the i-th distribution network, N der is the number of distribution networks containing distributed resources; P der，i represents the total power of distributed resources in the ith distribution network, represents the upper limit of the total power of distributed resources in the i-th distribution network;

[0032] ω i is the proportion of the secondary frequency regulation of the ith distribution network to the total secondary frequency regulation of the distribution network, which is adjusted according to the available capacity of the distributed resources of the ith distribution network at the moment;

[0033] The larger the available capacity of the distributed resources of the i-th distribution network, the greater the proportion of its secondary frequency regulation in the total secondary frequency regulation of the distribution network. i The larger the value, the greater the available capacity of the distributed resources in the ith distribution network. i Set it to zero and distribute its secondary frequency modulation evenly to the rest of the distribution network.

[0034] Furthermore, in step 6, according to the capacity of the distributed resources available for secondary frequency modulation, the control center regulates the secondary frequency modulation of different distributed resource nodes in a single distribution network in real time, as shown below:

[0035] For the distributed resource nodes that can be used for secondary frequency modulation in this distribution network, adjust them in sequence according to their current available capacity:

[0036]

[0037] Where, AGC der，i The secondary frequency modulation issued by the control center to the i-th distribution network, AGC der，i，j represents the secondary frequency modulation of the jth distributed resource node in the ith distribution network, N i is the total number of distributed resource nodes in the ith distribution network; V j is the voltage of each node in the distribution network, V min is the lower limit of the node voltage, V max is the upper limit of the node voltage;

[0038] For different distributed resource nodes of a single distribution network, nodes with high available capacity are adjusted first until the secondary frequency regulation requirements of this distribution network are met.

[0039] Beneficial effects of the present invention:

[0040] The present invention proposes a secondary frequency regulation control method, which is based on the dynamic joint simulation framework of the main and distribution networks established in Python, studies the secondary frequency regulation involving distributed resources, fully considers the intermittent nature of distributed resources, overcomes the dependence of traditional control methods on traditional thermal power units, and gives full play to the flexibility and controllability of distributed resources. In order to consider the intermittent nature of distributed resources, the total amount of secondary frequency regulation of the system is calculated in real time according to the PI control principle, and the secondary frequency regulation of the traditional generator sets of the main network and the distributed resources of the distribution network is adjusted in real time according to the margin of distributed resources that can be used for secondary frequency regulation, thereby improving the flexibility of the secondary frequency regulation process and the utilization rate of distributed resources, as well as the effectiveness of the secondary frequency regulation of distributed resources, and ensuring the stability of the distribution system. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 It is a flow chart of a secondary frequency modulation control method considering the intermittency of distributed resources based on a dynamic joint simulation framework of a main and distribution network according to an embodiment of the present invention;

[0043] Figure 2 It is a secondary frequency modulation time diagram of the main network traditional generator set and the distribution network distributed resources in an embodiment of the present invention;

[0044] Figure 3 is a time diagram of distributed resource power in a distribution network with insufficient available capacity according to an embodiment of the present invention;

[0045] Figure 4 This is a time diagram of the power of distributed resources in a distribution network with sufficient available capacity according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] As the proportion of renewable energy in the global power system continues to increase, distributed energy resources (DERs) are increasingly being used in power networks. Renewable energy sources such as wind and solar energy have gradually become an important part of the main distribution network due to their environmentally friendly characteristics and wide resource distribution advantages. However, the intermittent and volatile characteristics of distributed resources have brought new challenges to the stable operation of the power system.

[0048] In view of the intermittent characteristics of distributed energy and combined with the dynamic characteristics of the main distribution network, a secondary frequency regulation control method based on the dynamic joint simulation framework of the main distribution network considering the intermittent nature of distributed resources is proposed in this embodiment, giving full play to the flexibility and controllability of distributed resources and reducing dependence on traditional thermal power units. This control method will provide more efficient and stable secondary frequency regulation services for modern power grids with a large number of distributed resources, ensuring the frequency stability and safe operation of the power grid.

[0049] Specifically, the secondary frequency control method is based on the main distribution network dynamic joint simulation framework established in Python, fully considering the intermittent nature of distributed resources. The implementation block diagram is as follows Figure 1 As shown, the following steps are included:

[0050] Step 1: Establish a dynamic joint simulation framework for the main and distribution networks.

[0051] Firstly, the main network simulation tool andes and the distribution network simulation tool OpenDSS are integrated using the python HELICS simulation platform. The time synchronization mechanism can be used to realize the dynamic interconnection between the main network and the distribution network. The publish-subscribe mechanism can be used to realize the information interaction between the main network and the distribution network, reflecting the power flow distribution between the main and distribution networks, thereby realizing the construction of a dynamic joint simulation framework for the main and distribution networks.

[0052] Step 2: Monitor the main network frequency in real time at the control center to detect whether there is any frequency deviation.

[0053] Step 3, if the frequency deviates, the system will spontaneously perform a frequency modulation. The frequency modulation in this step refers to the automatic control process in which the control system of the unit in the power grid automatically controls the increase or decrease of the unit's active power, limits the frequency change of the power grid, and maintains a stable power grid frequency. Since this part of the content is not the focus of this embodiment, and the prior art has disclosed a large amount of content for this part of the technical means, the content of the system performing a frequency modulation in this step will not be described in detail in this embodiment.

[0054] Step 4: After the primary frequency modulation is completed, the total amount of the secondary frequency modulation (AGC) of the system is calculated in real time according to the PI control principle.

[0055] The method for calculating the total amount of secondary frequency modulation of the system in real time according to the PI control principle is:

[0056]

[0057] AGC total =-K P ACE-K I ∫ACE (2)

[0058] Among them, ACE in formula (1) is the regional control error, B is the natural frequency response coefficient, Δf is the difference between the actual frequency value f and the frequency reference value f0; AGC in formula (2) total It is the total amount of secondary frequency modulation of the system calculated according to the PI control principle, K P is the proportional coefficient in the PI controller, K I is the integral term coefficient in the PI controller.

[0059] Step 5: The control center controls the allocation ratio of the secondary frequency regulation (AGC) between the traditional generators in the main grid and the distributed resources in the distribution network in real time according to the current available capacity of the distributed resources.

[0060] According to the surplus of distributed resources available for secondary frequency regulation, the secondary frequency regulation of traditional power generation units in the main grid and distributed resources in the distribution network are regulated in real time to improve the utilization rate of distributed resources in the secondary frequency regulation process.

[0061] Considering the intermittent nature of distributed resources, the fluctuation of their available capacity is random and rapid, which makes it difficult to guarantee the available capacity at the time of frequency regulation. Therefore, in this step, the available capacity of distributed resources in each distribution network is monitored in real time, and the total capacity of distributed resources available for secondary frequency regulation is calculated in the control center. The control center will control the allocation ratio of secondary frequency regulation in the main network traditional generators and distribution network distributed resources in real time based on the current available capacity of distributed resources. The specific strategies are as follows:

[0062] AGC total =AGC trans +AGC der (3)

[0063]

[0064] In formula (3), AGC trans AGC is a secondary frequency modulation issued by the control center to the traditional units of the main grid. der The total amount of secondary frequency modulation released by the control center to the distributed resources of the distribution network;

[0065] In formula (4), α is the proportion of the secondary frequency modulation of distributed resources to the total secondary frequency modulation, which is adjusted according to the available capacity of the current distributed resources;

[0066] In formula (5), P der is the total power of distributed resources, This is the upper limit of the total power of distributed resources. This constraint clarifies the upper and lower limits of the power of distributed resources when participating in frequency modulation to ensure the safety and stability of the system.

[0067] When the available capacity of distributed resources is sufficient, the distributed resources are used as the main objects of secondary frequency regulation, and the traditional generators in the main grid are used as auxiliary and backup frequency regulation resources.

[0068] When the available capacity of distributed resources is insufficient, the traditional generator sets in the main grid are used as the main objects of secondary frequency regulation, and the distributed resources are used as auxiliary and backup frequency regulation resources.

[0069] In extreme cases, distributed resources have no available capacity, and only secondary frequency regulation is performed on traditional generators in the main grid to ensure the reliability of the secondary frequency regulation strategy.

[0070] Step 6: According to the margin of the distributed resources available for secondary frequency modulation (AGC), the secondary frequency modulation of different distribution network distributed resources and different distributed resource nodes of a single distribution network is regulated in real time.

[0071] For the real-time control of the secondary frequency modulation of distributed resources in different distribution networks, the intermittent nature of distributed resources is taken into account. According to the margin of distributed resources available for secondary frequency modulation, the secondary frequency modulation of distributed resources in different distribution networks is controlled in real time to improve the effectiveness and stability of the secondary frequency modulation of distributed resources. The specific methods are as follows:

[0072] According to the total available capacity of distributed resources in each distribution network, the secondary frequency regulation is allocated to each distribution network according to different proportions, using the following formula and restrictions:

[0073]

[0074] AGC der，i =ω i AGC der (7)

[0075]

[0076] In formula (6), AGC der，i is the secondary frequency modulation issued by the control center to the i-th distribution network, N der is the number of distribution networks containing distributed resources;

[0077] In formula (7), ω i is the proportion of the secondary frequency regulation of the ith distribution network to the total secondary frequency regulation of the distribution network, which is adjusted according to the available capacity of the distributed resources of the ith distribution network at the moment;

[0078] In formula (8), P der，i represents the total power of distributed resources in the ith distribution network, It represents the upper limit of the total power of distributed resources in the ith distribution network, ensuring the stability of the system.

[0079] The larger the available capacity of the distributed resources of the i-th distribution network, the greater the proportion of its secondary frequency regulation in the total secondary frequency regulation of the distribution network. i When the available capacity of the distributed resources of the i-th distribution network is seriously insufficient, ω i The frequency is set to zero and its secondary frequency modulation is evenly distributed to the rest of the distribution network, ensuring the stability of the distribution network.

[0080] For real-time control of the secondary frequency modulation of different distributed resource nodes in a single distribution network, the intermittent nature of distributed resources is taken into account. According to the margin of distributed resources available for secondary frequency modulation, the secondary frequency modulation of different distributed resource nodes in a single distribution network is controlled in real time to improve the effectiveness and stability of the secondary frequency modulation for distributed resources. The specific method is as follows:

[0081] For the distributed resource nodes that can be used for secondary frequency modulation in this distribution network, adjust them in sequence according to their current available capacity:

[0082]

[0083] In formula (9), AGC der，i，j represents the secondary frequency modulation of the jth distributed resource node in the ith distribution network, N i is the total number of distributed resource nodes in the i-th distribution network;

[0084] In formula (10), V j is the voltage of each node in the distribution network, V min is the lower limit of the node voltage, V max It is the upper limit of the node voltage. Distributed resources are intermittent, and they are prone to cause local voltage fluctuations when participating in secondary frequency regulation. Therefore, local voltage constraints need to be considered during the secondary frequency regulation process to ensure stable operation of the system.

[0085] For different distributed resource nodes of a single distribution network, nodes with high available capacity are adjusted first until the secondary frequency regulation requirements of this distribution network are met.

[0086] As another implementation application scenario of this embodiment, the secondary frequency modulation control method based on the main and distribution network dynamic joint simulation framework proposed in the present invention considering the intermittent distributed resources is adopted, and the results of the secondary frequency modulation process are tested as follows:

[0087] The power grid simulation model selected in this embodiment is a main grid model with two traditional generator sets and a distribution grid model with IEEE8500 nodes. The secondary frequency modulation method proposed in the embodiment is simulated and analyzed using the main and distribution grid joint simulation framework. When the main grid frequency fluctuates, the system spontaneously performs a primary frequency modulation and then starts the secondary frequency modulation. Figure 2 As shown, Figure 2 It is a secondary frequency regulation time diagram of traditional generators in the main grid and distributed resources in the distribution network. In the early stage of secondary frequency regulation, the available capacity of distributed resources is sufficient, and distributed resources are used as the main objects of secondary frequency regulation, and traditional generators in the main grid are used as auxiliary frequency regulation resources. Due to the intermittent nature of distributed resources, the available capacity of some distributed resources in the distribution network is insufficient in the later stage of secondary frequency regulation, and traditional generators in the main grid are used as the main objects of secondary frequency regulation, and distributed resources are used as auxiliary frequency regulation resources. Figure 3 and Figure 4The power-time diagrams of distributed resources in the distribution network with insufficient available capacity and sufficient available capacity, respectively.

[0088] This embodiment fully considers the intermittent nature of distributed resources, and the proposed control method overcomes the dependence of traditional control methods on traditional thermal power units, giving full play to the flexibility and controllability of distributed resources; the total amount of system AGC is calculated in real time according to the PI control principle, the intermittent nature of distributed resources is considered, and according to the margin of distributed resources that can be used for secondary frequency regulation, the AGC of the main network traditional generator sets and the distribution network distributed resources are regulated in real time, thereby improving the flexibility of the secondary frequency regulation process and the utilization rate of distributed resources; according to the capacity of distributed resources that can be used for secondary frequency regulation, the control center controls the method of AGC released to each distribution network in real time, thereby ensuring the stability of the distribution network system; according to the capacity of distributed resources that can be used for secondary frequency regulation, the control strategy for different distributed resource nodes in a single distribution network is implemented, thereby improving the effectiveness and stability of secondary frequency regulation for distributed resources.

Claims

1. A secondary frequency modulation control method considering the intermittency of distributed resources based on a dynamic joint simulation framework of a main distribution network, characterized in that: The following steps are involved: Step 1: Establish a dynamic joint simulation framework for the main and distribution networks; Step 2: Monitor the main network frequency in real time to detect whether the frequency is deviated; Step 3: If the frequency deviates, the system will automatically adjust the frequency; Step 4: After the primary frequency modulation is completed, calculate the total amount of secondary frequency modulation of the system; Step 5: The control center controls the allocation ratio of secondary frequency regulation between traditional generators in the main grid and distributed resources in the distribution network in real time according to the currently available capacity of distributed resources; Step 6: According to the margin of distributed resources available for secondary frequency modulation, the secondary frequency modulation of different distribution network distributed resources and different distributed resource nodes of a single distribution network is regulated in real time.

2. According to claim 1, a secondary frequency modulation control method considering the intermittency of distributed resources based on the dynamic joint simulation framework of the main and distribution networks is characterized in that: Step 1: Establishing a dynamic joint simulation framework for the main and distribution networks includes: The main network simulation tool andes and the distribution network simulation tool OpenDSS are integrated together through the HELICS simulation platform. The main network and the distribution network are dynamically interconnected using the time synchronization mechanism. The publish-subscribe mechanism is used to exchange information between the main network and the distribution network, reflecting the power flow distribution between the main and distribution networks, and realizing the construction of a dynamic joint simulation framework for the main and distribution networks.

3. According to claim 1, a secondary frequency modulation control method considering the intermittency of distributed resources based on the dynamic joint simulation framework of the main and distribution networks is characterized in that: In step 4, the method for calculating the total amount of secondary frequency modulation of the system in real time according to the PI control principle is: AGC total =-K P ACE-K I ∫ACE (2) Among them, ACE is the area control error, B is the natural frequency response coefficient, Δf is the difference between the actual frequency value f and the frequency reference value f0; AGC total It is the total amount of secondary frequency modulation of the system calculated according to the PI control principle, K P is the proportional coefficient in the PI controller, K I is the integral term coefficient in the PI controller.

4. According to claim 1, a secondary frequency modulation control method considering the intermittency of distributed resources based on the dynamic joint simulation framework of the main and distribution networks is characterized in that: In step 5, the control center controls the allocation ratio of secondary frequency regulation between traditional generators in the main grid and distributed resources in the distribution network in real time according to the current available capacity of distributed resources, as follows: AGC total =AGC trans +AGC der (3) Where, AGC trans AGC is a secondary frequency modulation issued by the control center to the traditional units of the main grid. der is the total amount of secondary frequency modulation issued by the control center to the distributed resources of the distribution network; α is the proportion of the secondary frequency modulation of distributed resources in the total secondary frequency modulation, which is adjusted according to the available capacity of the current distributed resources; P der is the total power of distributed resources, is the upper limit of the total power of distributed resources; When the available capacity of distributed resources is sufficient, the distributed resources are used as the main object of secondary frequency regulation, and the traditional generators in the main grid are used as auxiliary and backup frequency regulation resources; When the available capacity of distributed resources is insufficient, the traditional generators in the main grid are used as the main objects of secondary frequency regulation, and the distributed resources are used as auxiliary and backup frequency regulation resources; In extreme cases, distributed resources have no available capacity and only secondary frequency regulation is performed on traditional generators in the main grid.

5. According to claim 1, a secondary frequency modulation control method considering the intermittency of distributed resources based on the dynamic joint simulation framework of the main and distribution networks is characterized in that: In step 6, according to the capacity of the distributed resources available for secondary frequency regulation, the control center regulates the secondary frequency regulation of the distributed resources of different distribution networks in real time, using the following formula and constraints: AGC der，i =ω i AGC der (7) Where, AGC der，i is the secondary frequency modulation issued by the control center to the i-th distribution network, N der is the number of distribution networks containing distributed resources; P der，i represents the total power of distributed resources in the ith distribution network, represents the upper limit of the total power of distributed resources in the i-th distribution network; ω i is the proportion of the secondary frequency regulation of the ith distribution network to the total secondary frequency regulation of the distribution network, which is adjusted according to the available capacity of the distributed resources of the ith distribution network at the moment; The larger the available capacity of the distributed resources of the i-th distribution network, the greater the proportion of its secondary frequency regulation in the total secondary frequency regulation of the distribution network. i The larger the value, the greater the available capacity of the distributed resources in the ith distribution network. i Set it to zero and distribute its secondary frequency modulation evenly to the rest of the distribution network.

6. According to claim 1, a secondary frequency modulation control method considering the intermittency of distributed resources based on the dynamic joint simulation framework of the main and distribution networks is characterized in that: In step 6, according to the capacity of the distributed resources available for secondary frequency modulation, the control center regulates the secondary frequency modulation of different distributed resource nodes in a single distribution network in real time, as shown below: For the distributed resource nodes that can be used for secondary frequency modulation in this distribution network, adjust them in sequence according to their current available capacity: Where, AGC der，i The secondary frequency modulation issued by the control center to the i-th distribution network, AGC der，i，j represents the secondary frequency modulation of the jth distributed resource node in the ith distribution network, N i is the total number of distributed resource nodes in the ith distribution network; V j is the voltage of each node in the distribution network, V min is the lower limit of the node voltage, V max is the upper limit of the node voltage.

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