Electric energy-inertia collaborative optimization scheduling method, system and device considering frequency security constraint, and storage medium

Abstract

The invention discloses an electric energy-inertia collaborative optimization scheduling method, system and device considering frequency security constraints, and a storage medium. The method comprises the following steps: determining a system inertia demand index according to a system test result or a power grid requirement; establishing a system frequency safety constraint based on the system inertia demand index and the inertia supply characteristic of each generator set; with power grid economy optimization as a target, system frequency security constraints are introduced into the basic unit scheduling model, and an electric energy-inertia collaborative optimization scheduling model is constructed; according to the electric energy-inertia collaborative optimization scheduling model, the output and inertia supply quantity of each generator set is configured, and collaborative optimization scheduling of the output and inertia of the generator set is realized; according to the method, the limitation that only electric energy dispatching is concerned traditionally is broken through, inertia supply is brought into an optimization system, and the power grid economy is considered while the frequency safety is guaranteed by establishing a collaborative optimization model.

Description

Technical Field

[0001] This invention relates to the field of power system operation technology, specifically to an electric energy-inertia collaborative optimization scheduling method, system equipment, and storage medium that takes into account frequency security constraints. Background Technology

[0002] During the construction of the new power system, the gradual phasing out of coal-fired power units and the low inertia issues brought about by the integration of power electronic equipment such as high-proportion renewable energy and large-capacity DC transmission pose significant challenges to frequency security and stability. At the end of 2021, the National Energy Administration issued a revised version of the "Administrative Measures for Power Ancillary Services," proposing a new type of ancillary service based on inertia to address the impact of weak-inertia systems such as wind and solar power on grid operation under the background of new power system construction. Therefore, building an inertia market that conforms to my country's energy structure and resource characteristics is of great practical significance.

[0003] However, my country is still in the early stages of spot market development. The market mechanisms of the spot market and ancillary service market are still imperfect. The existing electricity spot market clearing and pricing algorithms are limited by the types of trading products in the domestic electricity spot market. The clearing and pricing algorithms only support the clearing and pricing of the power energy, peak shaving, frequency regulation and reserve markets, which is difficult to meet the inertia requirements of the new power system. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide an electric energy-inertia cooperative optimization scheduling method, system equipment, and storage medium that takes into account frequency security constraints, so as to solve the problems existing in the background art.

[0005] Technical Solution: The present invention provides a power-inertia coordinated optimization scheduling method considering frequency security constraints, comprising the following steps: determining the system inertia demand index based on system test results or grid requirements; establishing system frequency security constraints based on the system inertia demand index and the inertia supply characteristics of each generator unit; constructing a power-inertia coordinated optimization scheduling model by introducing system frequency security constraints into the basic generator unit scheduling model with the goal of grid economic optimization; and configuring the output and inertia supply of each generator unit according to the power-inertia coordinated optimization scheduling model to achieve coordinated optimization scheduling of unit output and inertia.

[0006] Furthermore, the determination of the system inertia requirement index is based on the minimum system inertia constant requirements specified in the national standard.

[0007] Furthermore, the system frequency safety constraints include: calculating the system's equivalent inertial time constant and equivalent kinetic energy, and simultaneously correlating the inertial time constant of each generator unit with its rated capacity to ensure that the system inertia level meets the requirements for safe operation.

[0008] Furthermore, the objective function of the power-inertia collaborative optimization scheduling model includes: the coal consumption cost of thermal power units, the start-up and shutdown cost, and the opportunity cost of new energy units reducing their output due to providing virtual inertia.

[0009] Furthermore, the power-inertia collaborative optimization scheduling model also includes: node power balance constraints, branch power flow safety constraints, unit output upper and lower limit constraints, unit start-up and shutdown time constraints, unit ramp rate constraints, and unit start-up and shutdown cost constraints.

[0010] Furthermore, configuring the output and inertia supply of generator sets includes: adjusting the start-stop status and output level of thermal power units, and controlling whether new energy units provide virtual inertia and the magnitude of their output; wherein, when new energy units provide virtual inertia, their maximum output is reduced accordingly, and the opportunity cost is related to the amount of virtual inertia provided.

[0011] The present invention discloses an electric energy-inertia cooperative optimization scheduling system that takes into account frequency security constraints, comprising:

[0012] Indicator module: Used to determine system inertia requirement indicators based on system test results or power grid requirements;

[0013] Frequency security constraint module: used to establish system frequency security constraints based on system inertia demand indicators and the inertia supply characteristics of each generator set;

[0014] Electric energy-inertia collaborative optimization scheduling module: This module is used to construct an electric energy-inertia collaborative optimization scheduling model with the goal of optimizing the economic efficiency of the power grid by introducing system frequency security constraints into the basic unit scheduling model.

[0015] Collaborative optimization scheduling module: It is used to configure the output and inertia supply of each generator unit according to the power-inertia collaborative optimization scheduling model, so as to realize the collaborative optimization scheduling of unit output and inertia.

[0016] Furthermore, in the indicator module, the determination of the system inertia requirement indicator is based on the minimum system inertia constant requirements specified in the national standard.

[0017] Furthermore, in the frequency safety constraint module, the system frequency safety constraint includes: calculating the system's equivalent inertial time constant and equivalent kinetic energy, and simultaneously associating the inertial time constant of each generator set with its rated capacity to ensure that the system inertia level meets the requirements for safe operation.

[0018] Furthermore, in the power-inertia collaborative optimization scheduling module, the objective function of the power-inertia collaborative optimization scheduling model includes: the coal consumption cost of thermal power units, the start-up and shutdown cost, and the opportunity cost of new energy units reducing output due to providing virtual inertia.

[0019] Furthermore, in the power-inertia collaborative optimization scheduling module, the power-inertia collaborative optimization scheduling model also includes: node power balance constraints, branch power flow safety constraints, unit output upper and lower limit constraints, unit start-up and shutdown time constraints, unit ramp rate constraints, and unit start-up and shutdown cost constraints.

[0020] Furthermore, configuring the output and inertia supply of generator sets includes: adjusting the start-stop status and output level of thermal power units, and controlling whether new energy units provide virtual inertia and the magnitude of their output; wherein, when new energy units provide virtual inertia, their maximum output is reduced accordingly, and the opportunity cost is related to the amount of virtual inertia provided.

[0021] An electronic device according to the present invention includes a memory and a processor. The memory stores a computer program, and the processor executes the program to implement the steps of the method.

[0022] The present invention discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method.

[0023] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: First, it clearly quantifies inertia demand: based on my country's "Technical Requirements for Inertia Support and Primary Frequency Regulation Capability of Power Systems," it clarifies the quantitative standards for inertia demand. Second, it employs scientific frequency constraint modeling: combining the system's equivalent inertia time constant, equivalent kinetic energy, and the calculation formula for the generator unit's inertia time constant, it deeply correlates inertia demand with the unit's inertia supply characteristics. Third, it breaks through the limitations of traditional approaches that only focus on power energy dispatch, incorporating inertia supply into the optimization system. By establishing a collaborative optimization model, it ensures frequency security while also considering grid economics. Fourth, the objective function covers the coal consumption cost of thermal power units, unit start-up and shutdown costs, and innovatively incorporates the opportunity cost of virtual inertia from new energy sources, ensuring the authenticity and comprehensiveness of economic optimization. Attached Figure Description

[0024] Figure 1 This is a flowchart of the present invention;

[0025] Figure 2 This is the modified IEEE 30-node system of this invention;

[0026] Figure 3 This invention relates to the total load, wind power, and photovoltaic output;

[0027] Figure 4 This refers to the unit output and system inertial constant at each moment when the present invention does not have frequency safety constraints;

[0028] Figure 5 This invention relates to the power output of generating units, the virtual inertia provided by new energy generating units, and the system inertia constant at each moment when there are no frequency safety constraints. Detailed Implementation

[0029] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0030] like Figure 1 As shown, this embodiment of the invention provides an electric energy-inertia cooperative optimization scheduling method that takes into account frequency security constraints, including the following steps:

[0031] Step 1: Determine the system inertia requirement based on system test results or power grid requirements;

[0032] Step 2: Establish system frequency security constraints based on system inertia requirements and unit inertia supply characteristics;

[0033] Step 3: Based on the basic unit scheduling model, with the goal of optimizing the power grid economy, and according to the system frequency security constraints, establish an energy-inertia collaborative optimization scheduling model that takes into account the frequency security constraints;

[0034] Step 4: Configure the generator output according to the electric energy-inertia collaborative optimization scheduling model that takes into account frequency safety constraints.

[0035] In step 1, the system inertia requirement index is determined based on system test results or grid requirements. my country's "Technical Requirements for Power System Inertia Support and Primary Frequency Regulation Capability" specifies that when the synchronous grid loses 10% of its load capacity, the system inertia constant... It should be no less than 1.5s.

[0036] In step 2, based on the system inertia requirements and the unit's inertia supply characteristics, system frequency security constraints are established:

[0037] The formulas for calculating the system's equivalent inertial time constant and equivalent kinetic energy are as follows:

[0038]

[0039]

[0040] In the formula, The system's equivalent inertial time constant. For the system's equivalent kinetic energy, The total rated capacity of the system connected to the grid. The total kinetic energy of the synchronizing machine. The equivalent total kinetic energy of the virtual inertia of new energy sources. This is the total kinetic energy in other forms.

[0041] The inertia of a generator set should be characterized by the generator set's inertial time constant, and the calculation formula is as follows: where, The generator set's inertial time constant. For the kinetic energy of the generator set, Rated capacity of generator set

[0042]

[0043] Inertial time constant With inertial constant The relationship is:

[0044]

[0045] Thus, the system's inertial constant is obtained. The calculation formula is as follows, where For the first The inertial constant of the Taiwanese generator set, For the first Rated capacity of the unit.

[0046]

[0047] To ensure the safe and stable operation of the system, the system frequency safety constraint is as follows: (The system inertia constant is required to be no less than 1.5s.)

[0048]

[0049] In step 3, based on the basic unit scheduling model and with the goal of optimizing the power grid economy, an energy-inertia collaborative optimization scheduling model that takes into account the frequency security constraints is established.

[0050] (31) Objective function

[0051]

[0052] In the objective function Represents the total cost within the scheduling period. Used to characterize the total number of units in the system Number of time periods Representing the The coal consumption function of a Taiwanese thermal power unit It is the coal consumption rate coefficient of the unit. Representing the Taiwanese unit in The magnitude of the actual output power within the time period, Representing the Taiwanese unit in Startup costs over a period of time Representing the Taiwanese unit in Downtime costs during the period In the first The opportunity cost incurred by the new energy unit due to the reduction in maximum output when providing virtual inertia within a time period is expressed as the product of the virtual inertia constant of the new energy unit and the unit opportunity cost.

[0053] (32) Node power constraints:

[0054]

[0055] Represents the susceptance matrix of network nodes. The bus voltage angle, This represents the total number of nodes in the system. In this model, reactive power is not considered; only active power flow constraints are taken into account. This constraint ensures that, in each time period, the load demand of each node in the system remains balanced with the total power generation of the connected units, thereby guaranteeing the power system's supply and demand balance.

[0056] (33) Branch power flow safety constraints:

[0057]

[0058] During power system operation, to ensure the safe and stable operation of the system, it is necessary to constrain the power flow of each transmission line. In the formula... Indicates transmission line During the period Active power transmitted internally. This represents the maximum power allowed to flow through the transmission line, where L is the total number of transmission lines. This constraint ensures that the active power transmitted by each transmission line at any given time does not exceed its safe current-carrying limit, thereby effectively preventing system failures caused by line overload and promoting the safe and reliable operation of the power system.

[0059] (34) Upper and lower limits of unit output constraints:

[0060]

[0061] Let be a binary state variable, representing the first... The generator set was at the Start / stop status for a time period (1 indicates running, 0 indicates stopping). and They represent the first The upper and lower limits of the unit's output are specified. Exceeding the limits may cause equipment damage.

[0062] (35) Unit start-up and shutdown time constraints:

[0063]

[0064] Before a generating unit can be shut down, it must meet the minimum startup time requirement; similarly, before being connected to the grid, it must meet the minimum shutdown time requirement. and Representing the Minimum start-up and shutdown time for the unit.

[0065] (36) Unit ramp rate constraint:

[0066]

[0067] and Representing the first The maximum ramp rate and maximum descent rate of the generator set are the upper limits of the increase or decrease in the unit's output power per unit time. and Representing the Minimum output power limits for each generating unit during startup and shutdown. Due to the physical characteristics and operating patterns of power generation equipment, units cannot achieve instantaneous power surges. To reflect this actual operating characteristic, constraints must be imposed on the power change rate of each unit to ensure that it varies within a safe and controllable range. Furthermore, there are also power output limits during start-up and shutdown: the maximum initial output power when the unit transitions from a shutdown state to startup. Conversely, when a unit is preparing to shut down, its power reduction must also follow the guidelines. These and other relevant constraints ensure the stability and safety of the unit's operation.

[0068] (37) Unit start-up and shutdown cost constraints:

[0069]

[0070] In the formula, and Corresponding to the first The startup and shutdown costs of the generating unit. The unit's power generation cost includes not only regular operating costs, but also additional costs for each startup and shutdown operation. Specifically, when the binary variable representing the unit's operating status changes from 0 to 1, it means the unit has completed the grid-connected startup process; when the binary variable representing the unit's operating status decreases from 1 to 0, it indicates that the unit has entered a grid-off shutdown state.

[0071] In step 4, based on the power-inertia collaborative optimization scheduling model that takes into account frequency safety constraints, the generator output and inertia supply are configured to achieve optimal configuration of the units.

[0072] This example uses a modified IEEE 30-node system as a computational example for verification. The modified IEEE 30-node system is as follows: Figure 2As shown, the system includes six traditional thermal power generating units, one wind turbine generating unit and one photovoltaic generating unit capable of providing virtual inertia, and one wind turbine generating unit and one photovoltaic generating unit unable to provide virtual inertia. Table 1 shows the operating parameters of different generating units. Units 1-6 are thermal power generating units, and units 7-8 are photovoltaic and wind turbine generating units capable of providing virtual inertia. When providing virtual inertia, their maximum output is reduced to 90% of the original. The rated capacities of the photovoltaic and wind turbine generating units unable to provide virtual inertia are 200MW and 300MW, respectively. Total load, wind power, and photovoltaic output are as follows: Figure 3 As shown.

[0073] Table 1 Unit Parameters

[0074] Unit 1 Unit 2 Unit 3 Unit 4 Unit 5 Unit 6 Unit 7 Unit 8 Node 1 2 5 8 11 13 15 18 Minimum output (MW) 30 15 10 10 5 5 0 0 Maximum output (MW) 150 140 100 100 100 100 100 100 Coal consumption coefficient a 0.038 0.25 0.01 0.01 0.01 0.01 0 0 Coal consumption coefficient b 20 20 40 40 40 40 0 0 Coal consumption coefficient c 0 0 0 0 0 0 0 0 Minimum start-stop time (h) 20 20 20 20 20 20 0 0 Climbing rate (MW / h) 50 50 50 50 50 50 / / Minimum output power (MW) 30 15 10 10 5 5 / / Start-stop fee (RMB) 60000 50000 40000 30000 10000 20000 0 0 Inertia constant (s) 6 5 4 4 3 3 3 3 Opportunity cost (RMB) / / / / / / 50 60

[0075] contrast Figure 4 , Figure 5 It can be seen that after adding frequency safety constraints, the unit start-up and shutdown combination changes, and the start-up unit 6 is replaced by unit 4 with a larger start-up inertia constant. In addition, the new energy unit provides virtual inertia to supplement the physical inertia at some times, thereby improving the system inertia level. The system inertia constant at each time meets the minimum inertia constant requirement.

[0076] This invention also provides an electric energy-inertia cooperative optimization scheduling system that takes into account frequency security constraints, comprising:

[0077] Indicator module: Used to determine system inertia requirement indicators based on system test results or power grid requirements;

[0078] Frequency security constraint module: used to establish system frequency security constraints based on system inertia demand indicators and the inertia supply characteristics of each generator set;

[0079] Electric energy-inertia collaborative optimization scheduling module: This module is used to construct an electric energy-inertia collaborative optimization scheduling model with the goal of optimizing the economic efficiency of the power grid by introducing system frequency security constraints into the basic unit scheduling model.

[0080] Collaborative optimization scheduling module: It is used to configure the output and inertia supply of each generator unit according to the power-inertia collaborative optimization scheduling model, so as to realize the collaborative optimization scheduling of unit output and inertia.

[0081] Among them, the determination of the system inertia requirement index in the indicator module is based on the minimum system inertia constant requirements specified in the national standard.

[0082] In the frequency safety constraint module, the system frequency safety constraint includes: calculating the system's equivalent inertial time constant and equivalent kinetic energy, and at the same time as relating the inertial time constant and rated capacity of each generator set to ensure that the system inertia level meets the requirements for safe operation.

[0083] In the power-inertia collaborative optimization scheduling module, the objective function of the power-inertia collaborative optimization scheduling model includes: the coal consumption cost of thermal power units, the start-up and shutdown cost, and the opportunity cost of new energy units reducing output due to providing virtual inertia.

[0084] In the power-inertia collaborative optimization scheduling module, the power-inertia collaborative optimization scheduling model also includes: node power balance constraints, branch power flow safety constraints, unit output upper and lower limit constraints, unit start-up and shutdown time constraints, unit ramp rate constraints, and unit start-up and shutdown cost constraints.

[0085] Configuring the output and inertia supply of generator sets includes: adjusting the start-stop status and output level of thermal power units, and controlling whether new energy units provide virtual inertia and the magnitude of their output; among which, the maximum output of new energy units is reduced accordingly when providing virtual inertia, and the opportunity cost is related to the amount of virtual inertia provided.

[0086] This invention also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the program to implement the steps of the method.

[0087] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method.

Claims

1. A method for coordinated optimization scheduling of electrical energy and inertia considering frequency security constraints, characterized in that, Includes the following steps: The system inertia demand index is determined based on system test results or grid requirements; system frequency security constraints are established based on the system inertia demand index and the inertia supply characteristics of each generator unit; with the goal of grid economic optimization, system frequency security constraints are introduced into the basic unit scheduling model to construct an energy-inertia collaborative optimization scheduling model; based on the energy-inertia collaborative optimization scheduling model, the output and inertia supply of each generator unit are configured to achieve collaborative optimization scheduling of unit output and inertia.

2. The power-inertia collaborative optimization scheduling method considering frequency security constraints according to claim 1, characterized in that, The system inertia requirement index is determined based on the minimum system inertia constant requirements specified in the national standard.

3. The power-inertia collaborative optimization scheduling method considering frequency security constraints according to claim 1, characterized in that, System frequency safety constraints include: calculating the system's equivalent inertial time constant and equivalent kinetic energy, and correlating the inertial time constant and rated capacity of each generator set to ensure that the system inertia level meets the requirements for safe operation.

4. The power-inertia collaborative optimization scheduling method considering frequency security constraints according to claim 1, characterized in that, The objective function of the power-inertia collaborative optimization scheduling model includes: the coal consumption cost of thermal power units, the start-up and shutdown cost, and the opportunity cost of new energy units reducing their output due to providing virtual inertia.

5. The power-inertia collaborative optimization scheduling method considering frequency security constraints according to claim 1, characterized in that, The power-inertia collaborative optimization scheduling model also includes: node power balance constraints, branch power flow safety constraints, unit output upper and lower limit constraints, unit start-up and shutdown time constraints, unit ramp rate constraints, and unit start-up and shutdown cost constraints.

6. The power-inertia collaborative optimization scheduling method considering frequency security constraints according to claim 1, characterized in that, Configuring the output and inertia supply of generator sets includes: adjusting the start-stop status and output level of thermal power units, and controlling whether new energy units provide virtual inertia and the magnitude of their output; among which, the maximum output of new energy units is reduced accordingly when providing virtual inertia, and the opportunity cost is related to the amount of virtual inertia provided.

7. An electric energy-inertia cooperative optimization scheduling system considering frequency security constraints, characterized in that, include: Indicator module: Used to determine system inertia requirement indicators based on system test results or power grid requirements; Frequency security constraint module: used to establish system frequency security constraints based on system inertia demand indicators and the inertia supply characteristics of each generator set; Electric energy-inertia collaborative optimization scheduling module: This module is used to construct an electric energy-inertia collaborative optimization scheduling model with the goal of optimizing the economic efficiency of the power grid by introducing system frequency security constraints into the basic unit scheduling model. Collaborative optimization scheduling module: It is used to configure the output and inertia supply of each generator unit according to the power-inertia collaborative optimization scheduling model, so as to realize the collaborative optimization scheduling of unit output and inertia.

8. The electric energy-inertia cooperative optimization scheduling system considering frequency security constraints according to claim 7, characterized in that, In the indicator module, the system inertia requirement indicator is determined based on the minimum system inertia constant requirements specified in the national standard.

9. The electric energy-inertia cooperative optimization scheduling system considering frequency security constraints according to claim 7, characterized in that, In the frequency safety constraint module, the system frequency safety constraint includes: calculating the system's equivalent inertial time constant and equivalent kinetic energy, and at the same time as relating the inertial time constant and rated capacity of each generator set to ensure that the system inertia level meets the requirements for safe operation.

10. The electric energy-inertia cooperative optimization scheduling system considering frequency security constraints according to claim 7, characterized in that, In the power-inertia collaborative optimization scheduling module, the objective function of the power-inertia collaborative optimization scheduling model includes: the coal consumption cost of thermal power units, the start-up and shutdown cost, and the opportunity cost of new energy units reducing output due to providing virtual inertia.

11. The electric energy-inertia cooperative optimization scheduling system considering frequency security constraints according to claim 7, characterized in that, In the power-inertia collaborative optimization scheduling module, the power-inertia collaborative optimization scheduling model also includes: node power balance constraints, branch power flow safety constraints, unit output upper and lower limit constraints, unit start-up and shutdown time constraints, unit ramp rate constraints, and unit start-up and shutdown cost constraints.

12. The electric energy-inertia cooperative optimization scheduling system considering frequency security constraints according to claim 7, characterized in that, Configuring the output and inertia supply of generator sets includes: adjusting the start-stop status and output level of thermal power units, and controlling whether new energy units provide virtual inertia and the magnitude of their output; among which, the maximum output of new energy units is reduced accordingly when providing virtual inertia, and the opportunity cost is related to the amount of virtual inertia provided.

13. An electronic device, characterized in that, It includes a memory and a processor, the memory storing a computer program, and the processor executing the program to implement the steps of the method according to claims 1-7.

14. A computer-readable storage medium, characterized in that, The device contains a computer program that, when executed by a processor, implements the steps of the method described in claims 1-7.

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