CN-122026403-A - Coordinated frequency adjusting system and method for multi-district interconnected power system

CN122026403ACN 122026403 ACN122026403 ACN 122026403ACN-122026403-A

Abstract

The invention belongs to the field of load frequency control of power systems, and relates to a collaborative frequency adjustment system and method for a multi-district interconnected power system. The method comprises the steps of obtaining regional control errors of each area according to inter-area tie line power deviation and system frequency deviation, constructing a memory output signal based on historical data of the state of the area, obtaining an equivalent control signal by utilizing a preset sliding mode surface function and solving according to a sliding mode control theory based on the memory output signal and the state of the system, and generating and transmitting control instructions aiming at a traditional generator set, an electric automobile cluster and a battery energy storage system according to the equivalent control signal and preset participation weight so as to cooperatively adjust the system frequency. The system provided by the invention realizes the cooperative regulation of various heterogeneous resources in the multi-zone interconnection system, improves the frequency regulation effect, improves the regulation potential evaluation precision, can ensure the accuracy and stability of frequency regulation, and effectively improves the capacity of the power grid for absorbing new energy and the operation elasticity.

Inventors

Dang Chaoliang
ZHAI JIAHAO
SONG WEIZHANG

Assignees

西安理工大学
西安拓疆电力科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260414

Claims (10)

1. The system comprises a plurality of interconnected power systems, a plurality of frequency adjusting system, a plurality of power system control system and a power system control system, wherein the interconnected power systems comprise at least two areas connected through a connecting wire; wherein the cooperative frequency adjustment system comprises a controller configured to: acquiring the regional control error of each station area according to the inter-station interconnection line power deviation and the frequency deviation of each station area; acquiring the state of each area, and constructing a memory output signal based on the historical data of the state of each area; Based on the regional control error, the memory output signal and the platform area state, utilizing a preset sliding mode surface function, and solving according to a sliding mode control theory to obtain an equivalent control signal; And generating and issuing control instructions for the traditional generator set, the electric automobile cluster and the battery energy storage system according to the equivalent control signals and preset participation weights so as to cooperatively adjust the frequency of the multi-district interconnected power system.
2. The coordinated frequency adjustment system of a multi-zone interconnected power system of claim 1, wherein the regional control error is obtained as follows: Wherein, the For the region index of the table, For the current time period of time, Is the first The area control error of the individual zones, Is the first Inter-zone link power deviations for individual zones, As a coefficient of frequency deviation (f-co) of the frequency deviation, Is the first Frequency deviation of the individual zones; The acquisition formula of the memory output signal is as follows: Wherein, the Is the first The memory output signals of the respective areas, For the size of the number of history data, , Is the first The zones of the individual zones output a parameter matrix, Is the first The zone status of the individual zones.
3. The multi-bay interconnected power system of claim 2, wherein the bay status includes at least a mechanical output power offset of the legacy genset, a governor position offset of the legacy genset, a power offset of the tie line, a frequency offset of each bay, an aggregate output power of the electric vehicle cluster, and an output power of the battery energy storage system.
4. The coordinated frequency adjustment system of a multi-zone interconnected power system of claim 1, wherein the sliding mode surface function is specifically as follows: Wherein, the Is the first The sliding mode surface function of each station area, Is the first Slip plane parameter vectors for each zone and selected to ensure Is not a singular item and is, Is the first The zone status of the individual zones, Is the first A zone state parameter matrix for each zone, As integral variable Corresponding first The zone status of the individual zones, For the current time period of time, For the size of the number of history data, Is the first A control signal parameter matrix for each zone, Is the first The controller gain of the individual zones, Is the first Integral value of area control error of each station area; the expression of the equivalent control signal is as follows: Wherein, the For an equivalent sliding mode control signal, Is the first The interference outside the area of the individual stations, Is the first The zones of the individual zones output a parameter matrix, Is the first Historical averages or estimates of individual zone states.
5. The coordinated frequency adjustment system of a multi-zone interconnected power system of claim 4, wherein the dynamic relationship of the zone state, the zone state parameter matrix, the zone output parameter matrix, and the integral value of the zone control error is defined by the following system state space equation and the dynamic equation of the system state: The system state space equation is: Wherein, the Is the first The derivative of the zone states of the individual zones, Is the first A matrix of state parameters for the individual zones, Is the first The zone status of the individual zones, Is the first A control signal parameter matrix for each zone, Is the first The interference coefficient matrix of the individual zones, For the output of the system, Is the first The zones of the individual zones output a parameter matrix, Is the first The external interference of the individual zones is such that, Is the first The controller gain of the individual zones, Is the first Historical averages or estimates of individual zone states, Is the first The equivalent perturbation matrix of the individual zones, Is the first The zone status of the individual zones, Is the first Slip plane parameter vectors for each zone and selected to ensure Is non-singular; the dynamic equation of the system state is as follows: Wherein, the Is the first The mechanical output power deviations of the individual zones are differentiated, Is the first The inter-zone link power bias differential for each zone, Is the first The cell frequency deviation of the individual cells is differentiated, Is the first The speed regulator position deviation differential of each bay, Is the first The output power of the electric automobile in each station area is differentiated, The power output by the battery energy storage system is differentiated, Is the first The mechanical output power deviation of the individual zones, Is the first The position deviation of the speed regulator of each station area, Is the first Turbine/turbine time constants for each land, Is the first Inter-zone link power deviations for individual zones, Is the first With the first station area Inter-region synchronization coefficients for the individual zones, Is the first The cell frequency deviation of the individual cells, Is adjacent to the first The cell frequency deviation of the individual cells, Is the first The generator inertia constant of the individual bay, Is the first The generator damping coefficient of each station area, Is the first The load deviation of the individual zones is determined, Is the first Renewable energy output power of individual bays, Is the first The sag factor of the individual zones, Is the first The time constant of the governor of the individual zones, Is the first Integration of ACE for individual zones, The proportion coefficient is participated in for the traditional generator set, Is the first The control signals of the individual zones are transmitted, Is the first The electric vehicles in each station area output power, The method is used for the participation proportion coefficient of the electric automobile, Is the first The control coefficients of the electric vehicles in each platform area, Is the first The time constant of the electric automobile in each station area, The power is output for the battery energy storage system, The participation ratio of the battery energy storage system is, The control coefficient of the battery energy storage system is calculated, Time constant for the battery energy storage system.
6. The coordinated frequency adjustment system of a multi-zone interconnected power system of claim 5, wherein the external disturbance or load deviation in the system state space equation comprises a power output of a photovoltaic power generation unit, and the power output of the photovoltaic power generation unit is obtained according to the following formula: Wherein, the Is the first The power output of the photovoltaic power generation units of the individual bays, For the gain of the photovoltaic power generation unit, As a function of the time constant, In order for the laplace operator to be useful, Is the first Solar irradiance intensity of individual zones.
7. The collaborative frequency adjustment system of a multi-zone interconnected power system according to claim 1, wherein the controller is further configured to adaptively select a controller gain of a battery energy storage system according to a zone frequency deviation after the battery energy storage system receives the control command of the battery energy storage system, according to the equivalent control signal and a preset participation weight, wherein the control command is generated and issued for the conventional generator set, the electric vehicle cluster and the battery energy storage system, and the control gain is specifically as follows: When the frequency deviation of the platform area is larger than the forward threshold value of the dead zone of response frequency change, the gain of the controller of the battery energy storage system is larger than zero, and the battery energy storage system is in a discharging state; When the frequency deviation of the platform area is larger than or equal to the negative threshold value of the dead zone of the response frequency change and smaller than or equal to the positive threshold value of the dead zone of the response frequency change, the gain of a controller of the battery energy storage system is equal to zero, and the battery energy storage system stops charging and discharging; when the frequency deviation of the station area is smaller than the negative threshold of the dead zone of response frequency change, the gain of a controller of the battery energy storage system is smaller than zero, and the battery energy storage system is in a charging state; The acquisition formula of the controller gain of the battery energy storage system is specifically as follows: Wherein, the For the controller gain of the battery energy storage system, In order to control the gain for the discharge, In order to control the gain of the charge, For a desired charging power ratio, In order to achieve a desired discharge power ratio, In response to the forward threshold of the frequency change, In response to a negative-going threshold of frequency change, In response to the forward threshold of the frequency change dead band, A negative threshold for a dead zone in response to frequency change.
8. The multi-zone interconnected power system of claim 7, wherein the controller is further configured to monitor and manage a state of charge of the battery energy storage system when generating the control command for the battery energy storage system, the state of charge of the battery energy storage system having an acquisition formula as follows: Wherein, the For the operational performance of the battery energy storage system, An initial value representing the state of charge, Representing the storage capacity of the stored energy, For the output power of the battery energy storage system, For the output voltage of the battery energy storage system, Is the output current of the battery energy storage system.
9. The multi-zone interconnected power system collaborative frequency adjustment system of claim 1, wherein the engagement weights include a traditional genset engagement weight, an electric vehicle engagement weight, and a battery energy storage system engagement weight, the traditional genset engagement weight, the electric vehicle engagement weight, and the battery energy storage system engagement weight satisfying the following relationship: Wherein, the For the participation weight of the traditional generator set, The electric automobile is used for participating in the weight, The weight is participated in for the battery energy storage system.
10. A method for adjusting cooperative frequencies of a multi-district interconnection power system, which is applied to the multi-district interconnection power system cooperative frequencies adjustment system according to any one of claims 1 to 9, the method comprising: s1, acquiring inter-station interconnecting line power deviation and frequency deviation of each station; s2, acquiring the area control error of each station area according to the inter-station interconnection line power deviation and the frequency deviation of each station area; s3, obtaining the state of each area, and constructing a memory output signal based on the historical data of the state of each area; s4, based on the regional control error, the memory output signal and the platform area state, utilizing a preset sliding mode surface function, and solving according to a sliding mode control theory to obtain an equivalent control signal; and S5, generating and issuing control instructions for the traditional generator set, the electric automobile cluster and the battery energy storage system according to the equivalent control signals and preset participation weights so as to cooperatively adjust the frequency of the multi-zone interconnected power system.

Description

Coordinated frequency adjusting system and method for multi-district interconnected power system Technical Field The invention belongs to the field of load frequency control of power systems, and relates to a collaborative frequency adjustment system and method for a multi-district interconnected power system. Background Under the global energy transformation and the strategic driving of 'two carbons', a novel electric power system taking new energy as a main body is being constructed in an accelerating way. In the process, the distributed power source represented by the photovoltaic is connected into the large-scale electric automobile in a high proportion and is widely popularized, so that remarkable cleaning benefit is brought, and meanwhile, a serious challenge is brought to the safe and stable operation of a power system, particularly a power distribution network layer. On one hand, the charging load of the electric automobile has strong randomness and space-time aggregation characteristics, is easy to be overlapped with the traditional load peak of a power grid to cause local overload and voltage out-of-limit, and on the other hand, the photovoltaic power generation output is obviously intermittent and wavy under the influence of weather, and forms sharp supply and demand matching contradiction with the same uncertain charging load in time-space, thereby severely restricting the capacity of the power grid for absorbing new energy and the operation elasticity. In order to cope with the challenges, the better resource utilization of adjustable loads such as electric automobiles has become a key research direction. The prior art focuses mainly on improving the matching of distributed energy sources and loads inside a single area through an optimization algorithm or frequency adjustment under a simplified model. However, when the complex scene of high-proportion new energy permeation, multi-type heterogeneous resource (such as a traditional unit, energy storage and electric vehicle cluster) aggregation and multi-area interconnection is faced, the existing scheme still has obvious limitations that firstly, the dynamic characterization and online evaluation capability of multiple uncertainties such as output and charging behaviors of photovoltaic and electric vehicles is insufficient, so that the evaluation precision of adjustment potential is limited, secondly, the robustness of a cooperative control strategy is to be enhanced, the accuracy and stability of frequency adjustment are difficult to ensure under the complex disturbance and communication constraint, thirdly, the research on a comprehensive control system aiming at the mutual power and frequency cooperative support among a plurality of interconnected stations is insufficient, and a global optimization scheme capable of comprehensively planning the mutual power and the mutual power among the stations is lacking. Disclosure of Invention The invention aims to provide a collaborative frequency adjustment system and a collaborative frequency adjustment method for a multi-district interconnection power system, which are used for solving the technical problems that multiple uncertainty disturbance in the multi-district interconnection system is difficult to evaluate accurately, the robustness of a collaborative control strategy is insufficient and the frequency adjustment precision and stability are reduced under the access of high-proportion new energy. In order to achieve the above purpose, the invention is realized by adopting the following technical scheme: the invention provides a collaborative frequency adjustment system of a multi-district interconnection power system, which comprises at least two districts connected by a connecting wire, wherein each district comprises a traditional generator set, a battery energy storage system and an electric automobile cluster connected by an aggregator; the cooperative frequency adjustment system includes a controller configured to: acquiring the regional control error of each station area according to the inter-station interconnection line power deviation and the frequency deviation of each station area; acquiring the state of each area, and constructing a memory output signal based on the historical data of the state of each area; Based on the regional control error, the memory output signal and the platform area state, utilizing a preset sliding mode surface function, and solving according to a sliding mode control theory to obtain an equivalent control signal; And generating and issuing control instructions for the traditional generator set, the electric automobile cluster and the battery energy storage system according to the equivalent control signals and preset participation weights so as to cooperatively adjust the frequency of the multi-district interconnected power system. In a second aspect, the present invention provides a method for adjusting cooperative frequencies of a multi-district interconn