CN-122000992-A - Island micro-grid optimal scheduling method and system considering whole frequency response process

CN122000992ACN 122000992 ACN122000992 ACN 122000992ACN-122000992-A

Abstract

The invention discloses an island micro-grid optimal scheduling method and system considering the whole frequency response process, belonging to the field of island micro-grid optimal scheduling, wherein K-means clustering is adopted to generate a photovoltaic output typical day scene, and an island micro-grid basic random optimal scheduling model is constructed; the method comprises the steps of dividing frequency response after island micro-grid disturbance into three parts, constructing an expression of island micro-grid disturbance power and mechanical inertia based on frequency response characteristics of a generator N-1 off-grid disturbance, respectively constructing linearization frequency stability constraint aiming at the three parts of the frequency response through cooperation of multiple frequency modulation resources, and integrating the linearization frequency stability constraint into an island micro-grid basic random optimization scheduling model to form an island micro-grid optimization scheduling method considering the whole frequency response process. The invention ensures stable frequency under the N-1 event, digs the response potential of source-load-storage, reduces the running cost and the dependence of a generator, and supports the safe and efficient running of the island micro-grid.

Inventors

YAO LIANGZHONG
CHAI YUKUN
LIU YUNXIN
LIAO SIYANG
SHENG WANXING
LIU KEYAN

Assignees

武汉大学
中国电力科学研究院有限公司

Dates

Publication Date: 20260508
Application Date: 20251231

Claims (10)

1. An island micro-grid optimal scheduling method considering the whole frequency response process is characterized by comprising the following steps of: generating a photovoltaic output typical day scene by adopting K-means clustering; Based on an island micro-grid comprising a generator, a photovoltaic power generation system, an energy storage system and a load, constructing an island micro-grid basic random optimization scheduling model comprising a two-stage cost objective function and multi-dimensional constraint; Dividing the frequency response of the island micro-grid after power disturbance into three parts, wherein the three parts are respectively inertia response at the initial moment of disturbance, primary frequency response after disturbance occurrence and secondary frequency response after the frequency reaches a quasi-steady state; Obtaining disturbance power and mechanical inertia of the island micro-grid based on frequency response characteristics of the generator N-1 under off-grid disturbance; Based on the three parts after frequency response division, the disturbance power and the mechanical inertia of the island micro-grid are combined to respectively construct linearization frequency stability constraint, and the linearization frequency stability constraint is integrated into a basic random optimization scheduling model of the island micro-grid to finish island micro-grid optimization scheduling considering the whole frequency response process.
2. The island micro-grid optimizing and scheduling method considering the whole frequency response process according to claim 1, wherein the constructing of the island micro-grid substantially random optimizing and scheduling model containing the two-stage cost objective function and the multi-dimensional constraint comprises the following steps: Constructing a two-stage cost objective function, wherein the two-stage cost objective function comprises a first-stage cost objective function and a second-stage cost objective function, the first-stage cost objective function comprises the start-stop cost of the generator, the power generation cost and the frequency modulation standby cost of the energy storage system, and the second-stage cost objective function comprises the primary standby cost and the secondary standby cost of the generator, the primary standby cost of the photovoltaic system and the unnecessary load removal cost; Constructing multi-dimensional constraint, including power balance constraint, generator output limit constraint, generator primary and secondary frequency modulation standby constraint, energy storage system operation constraint, energy storage system frequency modulation standby constraint, photovoltaic frequency modulation standby constraint and unnecessary load removal power constraint in an island micro-grid; And constructing a basic random optimization scheduling model of the island micro-grid according to the stage cost objective function and the multidimensional constraint.
3. The optimization scheduling method for the island micro-grid taking the whole frequency response process into consideration as claimed in claim 1, wherein the frequency response after the island micro-grid perturbs the power is divided into three parts, and the method comprises the following steps: Assuming that the disturbance occurs at time t 0 , in the frequency response, the frequency of the island micro-grid reaches a quasi-steady state at time t 1 and returns to a nominal value at time t 2 ; The inertia response of the divided disturbance initial moment corresponds to the moment t 0 , the primary frequency modulation response corresponds to the period (t 0 ,t 1 ) after the disturbance occurs, and the frequency reaches the secondary frequency response corresponds to the period (t 1 ,t 2 ) after the quasi-steady state.
4. The optimization scheduling method of the island micro-grid taking the whole frequency response process into consideration as claimed in claim 1, wherein obtaining the disturbance power and the mechanical inertia of the island micro-grid based on the frequency response characteristic of the generator N-1 under off-grid disturbance comprises the following steps: the disturbance power of the island micro-grid is an instantaneous mutation value of the active power of the shutdown generator, and the expression is as follows: , Wherein, the Delay for unnecessary load shedding; a time step discretized for a frequency rate response process; The disturbance power occurring in the N-1 event; For the machine set The amount of unnecessary load shedding under off-grid events; First indicating photovoltaic output A typical scenario; Represent the first A scheduling period; representing the first after disturbance power A plurality of discrete points; the mechanical inertia of the island micro-grid is expressed as the sum of the mechanical inertias of the remaining on-line units except for the shutdown generator.
5. The optimization scheduling method of the island micro-grid considering the whole frequency response process according to claim 1, wherein the method is characterized in that based on three parts after frequency response division, combined with disturbance power and mechanical inertia of the island micro-grid, linearization frequency stability constraint is respectively constructed, and comprises the following steps: the method comprises the steps of carrying out constraint on the response power of an energy storage system and the frequency change rate of an island micro-grid based on inertia response at the initial disturbance moment, carrying out power limiting on the inertia response power of the energy storage system, and obtaining corresponding equality constraint; based on primary frequency response after disturbance occurs, restraining frequency deviation after disturbance, steady-state frequency deviation and response power of each frequency modulation resource; And based on the secondary frequency response after the frequency reaches a quasi-steady state, restraining the secondary frequency modulation reserve of the island micro-grid, and assuming that the generators in the grid can participate in secondary frequency modulation and simultaneously, not considering the recovery of unnecessary load removal.
6. The optimization scheduling method of the island micro-grid considering the whole frequency response process according to claim 5, wherein the obtaining of the frequency change rate constraint of the island micro-grid based on the inertia response at the initial moment of disturbance comprises the following steps: , Wherein, the In order to allow for a maximum rate of frequency change, To limit the inertia response power at the initial moment of disturbance of the energy storage system, For the disturbance power occurring in the N-1 event, Representing an electric generator Mechanical inertia of the island micro-grid at shutdown N-1 event, Time is indicated.
7. The optimization scheduling method for the island micro-grid taking the whole frequency response process into consideration as claimed in claim 5, wherein the constraint on the frequency deviation after disturbance, the steady-state frequency deviation and the response power of each frequency modulation resource comprises the following steps: Constructing an island micro-grid system frequency response model considering power limiting; Based on the island micro-grid system frequency response model, the coupling relation between each resource response power and frequency deviation is processed through a discretization method, wherein the power limiting is performed by applying a penalty variable, and a linearization frequency stability constraint is constructed.
8. The island micro-grid optimization scheduling method considering the whole process of the frequency response according to claim 5, further comprising, after the secondary frequency response: different N-1 events are distinguished by adopting secondary frequency modulation reserve, and the expression is as follows: , Wherein, the Is the sum of the steady-state frequency response powers at which all the frequency modulation resources are limited at steady-state frequency, For running generator g in period t for off-grid generator The secondary frequency modulation reserve released in time, For the disturbance power occurring in the N-1 event, Cutting off the unnecessary load of the unit under the off-grid event; is the reference power.
9. An island micro-grid optimal scheduling system considering the whole frequency response process, which is characterized by comprising: The data processing module is used for classifying and aggregating the acquired historical photovoltaic output time sequence data by adopting K-means clustering to generate a photovoltaic output typical day scene; The island micro-grid basic random optimization scheduling model building module is used for building an island micro-grid basic random optimization scheduling model containing a two-stage cost objective function and multi-dimensional constraint based on the island micro-grid containing a generator, a photovoltaic energy storage system and a load; The response dividing module is used for dividing the frequency response of the island micro-grid after the disturbance power into three parts, namely inertia response at the initial moment of disturbance, primary frequency response after the disturbance occurs and secondary frequency response after the frequency reaches a quasi-steady state; the frequency response characteristic module is used for obtaining disturbance power and mechanical inertia of the island micro-grid based on frequency response characteristics of the generator N-1 under off-grid disturbance; And the island micro-grid optimization scheduling module is used for respectively constructing linearization frequency stability constraint based on three parts of frequency response divided and combining disturbance power and mechanical inertia of the island micro-grid, integrating the linearization frequency stability constraint into a basic random optimization scheduling model of the island micro-grid, and completing island micro-grid optimization scheduling considering the whole frequency response process.
10. An electronic device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor, when executing the computer program, implements the steps of the island micro-grid optimized scheduling method taking into account the overall frequency response process as defined in any one of claims 1-8.

Description

Island micro-grid optimal scheduling method and system considering whole frequency response process Technical Field The invention belongs to the field of island micro-grid optimal scheduling, and particularly relates to an island micro-grid optimal scheduling method and system considering the whole frequency response process. Background Under the guidance of global energy clean transformation and sustainable development targets, island micro-grids become a core solution for reliably supplying power to island, ship and other isolated areas by virtue of flexible integration capability of distributed energy, and the island micro-grids have increasingly prominent effects in the aspects of improving energy supply cleanliness, guaranteeing energy safety and the like. Along with the rapid development of resources based on inverters such as photovoltaic, energy storage and the like, the permeability of the photovoltaic energy storage system in an island micro-grid is continuously improved, the energy structure is pushed to be transformed to low carbonization, and new technical challenges are brought. The resource does not have inertia and frequency modulation capability of the traditional generator, so that the island micro-grid generally faces the problems of insufficient inertia and deficient primary frequency modulation capacity, the island operation characteristics enable the island micro-grid to be incapable of obtaining frequency support of an external grid, the frequency is easy to be greatly fluctuated when the island micro-grid encounters disturbance power, and the safe and stable operation of the system is seriously threatened. Currently, island micro-grid dispatching needs to balance core contradiction of stable frequency guarantee and operation economy. Meanwhile, the frequency modulation supporting effects of different control modes are different, the whole process of frequency response is difficult to be covered by the traditional scheduling model, and the cooperative frequency modulation potential of various resources is difficult to be fully excavated. On the premise of guaranteeing stable frequency, optimizing a scheduling strategy to reduce operation cost becomes a key problem to be solved in the island micro-grid development process. Therefore, the island micro-grid optimization scheduling technology considering the whole frequency response process is developed, the frequency modulation effect of multiple resources such as a generator, energy storage, photovoltaics and the like is fully exerted, the unification of safety stability and operation economy is realized, and the island micro-grid optimization scheduling technology becomes a core requirement for supporting the high-quality development of the island micro-grid. Disclosure of Invention Aiming at the technical problems that the existing island micro-grid is insufficient in inertia and deficient in primary frequency modulation capacity due to improvement of the permeability of inverter type resources such as photovoltaic, frequency is easy to fluctuate greatly when disturbance power is encountered, and the existing island micro-grid is difficult to balance frequency stability guarantee and operation economy, reserved frequency modulation reserves can weaken the system operation economy, the invention provides an optimized dispatching method for dividing frequency response into three stages and constructing linearization frequency stability constraint in a targeted manner, and fully excavates the cooperative frequency modulation potential of a generator, a photovoltaic, an energy storage system and a load through a basic random optimized dispatching model containing a two-stage cost objective function, reduces the dependence of operation cost and a traditional generator, and can ensure the frequency stability under an N-1 event and support the safe and stable operation of the island micro-grid. According to an aspect of the present disclosure, there is provided an island micro-grid optimization scheduling method considering a frequency response overall process, including: generating a photovoltaic output typical day scene by adopting K-means clustering; Based on an island micro-grid comprising a generator, a photovoltaic power generation system, an energy storage system and a load, constructing an island micro-grid basic random optimization scheduling model comprising a two-stage cost objective function and multi-dimensional constraint; Dividing the frequency response of the island micro-grid after power disturbance into three parts, wherein the three parts are respectively inertia response at the initial moment of disturbance, primary frequency response after disturbance occurrence and secondary frequency response after the frequency reaches a quasi-steady state; Obtaining disturbance power and mechanical inertia of the island micro-grid based on frequency response characteristics of the generator N-1 under off-grid disturbance; Based on th