CN-122026447-A - Hybrid energy storage system power grid power cooperative control method based on emergency working condition

CN122026447ACN 122026447 ACN122026447 ACN 122026447ACN-122026447-A

Abstract

The invention belongs to the technical field of hybrid energy storage cooperative control, and particularly discloses a hybrid energy storage system grid power cooperative control method based on emergency working conditions, which is beneficial to improving regulation and control efficiency by dividing a response process into a first frequency modulation stage, a second frequency modulation stage and a third frequency modulation stage under the condition that grid power enters the emergency working conditions, setting dominant energy storage types according to stage characteristics in each stage, realizing self-adaptive coupling of energy storage type advantages and response stages, meanwhile, the state of charge, the geographic position and the available power of all the energy storage units of different energy storage types are obtained, and the feature set of the energy storage units is constructed, so that the leading unit and the following unit are selected from the feature set of the energy storage units according to the leading energy storage type of the stage in each stage, a self-adaptive coordination mechanism inside the energy storage clusters of the same type can be built in the stage, the optimal distribution of power instructions in the clusters is realized, and the overall cycle life of the energy storage system is effectively prolonged.

Inventors

DU CHENGGANG
WU LAN
HAO FEI
ZHANG YIN
XIE KAI
GU QUAN
GUO LEI
ZHU BIAO
WANG YUJUN
CHEN JIAN

Assignees

南京南瑞继保电气有限公司
内蒙古能源集团有限公司

Dates

Publication Date: 20260512
Application Date: 20260414

Claims (10)

1. The power grid power cooperative control method of the hybrid energy storage system based on the emergency working condition is characterized by comprising the following steps of: When the detected power grid frequency is lower than the lower limit of the normal range, determining to enter an emergency working condition; acquiring the charge states, the geographic positions and the available power of all flywheel, battery and molten salt energy storage units, and constructing an energy storage unit feature set; Dividing the response process of the emergency working condition into a first frequency modulation stage, a second frequency modulation stage and a third frequency modulation stage, wherein each stage takes flywheel energy storage, battery energy storage and fused salt heat storage as dominant energy storage types; Selecting a leading unit and a following unit from the characteristic set of the energy storage unit according to the leading energy storage type of the stage in each stage, and preselecting a preparation unit for the subsequent stage; Controlling the coordinated output power of the leading unit and the following unit in the current stage, judging whether other types of energy storage intervention are needed according to the real-time state, and selecting the intervention power output of the adaptive unit when the intervention is needed; when the state of charge of the leading unit is monitored to be reduced in the current stage and leading right replacement is required to be triggered, selecting a new leading unit from the energy storage units of the same type; And executing each stage in sequence until the power grid frequency is recovered to the normal range, and relieving the emergency working condition.
2. The method for collaborative control of power of a hybrid energy storage system based on emergency conditions of claim 1, wherein the constructing the feature set of the energy storage unit comprises the following steps: Reading state of charge data corresponding to the current rotating speed from a flywheel control system of each flywheel energy storage unit; reading state of charge data corresponding to the current residual capacity from a battery management system of each battery energy storage unit; reading state of charge data corresponding to the current heat reserves from a heat energy storage management system of each molten salt heat storage unit; Reading the maximum power upper limit which is currently allowed to be output from the power conversion system of each energy storage unit in real time to be used as available power data; locating the geographical location of each energy storage unit at its installation location by means of a locating device; and carrying out associated storage on the collected state of charge, available power and geographic position according to the energy storage type of each energy storage unit to generate an energy storage unit characteristic set.
3. The method for collaborative control of grid power of a hybrid energy storage system based on emergency conditions as set forth in claim 1, wherein the first, second and third phases are defined by the following division: Calculating the change rate of the power grid frequency in real time, recording the moment as the starting point of the first frequency modulation stage when the change rate of the power grid frequency exceeds a preset impact threshold value for the first time, and recording the moment as the ending point of the first frequency modulation stage when the change rate of the power grid frequency falls back below the impact threshold value from a peak value; taking the end point time of the first frequency modulation stage as the start point of the second frequency modulation stage, monitoring the return process of the power grid frequency in real time, and taking the time when the frequency reaches the frequency recovery boundary point for the first time as the end point of the second frequency modulation stage; And taking the end point moment of the second frequency modulation stage as the starting point of the third frequency modulation stage, monitoring the relative position of the power grid frequency and the lower limit of the normal range in real time, and recording the moment as the end point of the third frequency modulation stage when the power grid frequency reaches the lower limit of the normal range for the first time.
4. The method for collaborative control of power grid power of a hybrid energy storage system based on emergency conditions as set forth in claim 1, wherein the selecting the master unit comprises the following steps: screening all energy storage units of the same type from the characteristic set of the energy storage units according to the dominant energy storage type of the stage in each stage, and further eliminating the units with charge states lower than a preset participation threshold; The rest energy storage units of the same type are respectively arranged from the high to the low of the state of charge and from the near to the far of the geographical position to the power grid frequency disturbance point, so as to obtain the optimal sequencing result of the state of charge and the electric distance; Respectively extracting the ranking number of each energy storage unit from the charge state and electric distance optimal ranking results, and adding to obtain a comprehensive optimal ranking value; and selecting the energy storage unit with the minimum comprehensive preferred sorting value as a leading unit of the current stage.
5. The method for collaborative control of grid power of a hybrid energy storage system based on emergency conditions of claim 4 wherein the following unit is configured to: after the selected leading units are removed, the remaining energy storage units of the same type are ranked from high to low according to the charge states, and a plurality of units ranked at the front are selected as following units of the current stage.
6. The hybrid power grid power coordinated control method based on emergency conditions of claim 1, wherein pre-selecting the preliminary unit process for the subsequent stage comprises: In the execution of the current stage, according to the dominant energy storage type of the next stage, screening all energy storage units conforming to the energy storage type from the characteristic set of the energy storage units, and eliminating the units which are put into operation in the current stage and have charge states lower than the participation threshold; And sorting the rest units according to the charge states from high to low, and selecting at least two units with the front sorting as preparation units of the next stage respectively.
7. The method for collaborative control of grid power of a hybrid energy storage system based on emergency conditions as set forth in claim 1, wherein the controlling of the dominant unit and follower unit collaborative output power in the current stage is performed by the following steps: the control leading unit operates in a voltage source mode, and the output power value of the leading unit is adjusted in real time according to the deviation degree of the power grid frequency and the normal range; Acquiring the current total power shortage of the power grid in real time, subtracting the current actual output power of the master unit from the total power shortage, and calculating the residual power requirement to be jointly born by the following units; distributing the residual power demand of all the following units according to the proportion of the current available power of the following units to the total available power of all the following units, and synchronously issuing a power instruction; Monitoring the charge states of all the following units in real time, temporarily removing any unit from the allocation list when the charge state of the unit is reduced to a participation threshold, and reallocating the original power share of the unit according to the available power proportion of the remaining following units; when the subsequent state of charge of the removed unit is restored to be above the participation threshold, the removed unit is re-included in the allocation list, and the allocation proportion of each unit is recalculated.
8. The method for collaborative control of grid power of a hybrid energy storage system based on emergency conditions of claim 7, wherein the determining whether other types of energy storage intervention are needed, and selecting an adaptive unit to intervene in power output when intervention is needed comprises: In the first frequency modulation stage, when the charge states of all flywheel following units are lower than the participation threshold and the power grid frequency change rate continuously exceeds the impact threshold, judging to trigger battery intervention; in the second frequency modulation stage, when the rate of decrease of the charge state of the leading battery unit exceeds a rate limit value and the duration exceeds a preset duration, determining to trigger molten salt intervention; In the second frequency modulation stage, when the power grid frequency change rate instantaneously exceeds the impact threshold, judging to trigger flywheel intervention, selecting a flywheel unit with the highest response speed and the charge state higher than the participation threshold to instantaneously output power in a voltage source mode, and exiting after the power grid frequency change rate is restored below the impact threshold; In the third frequency modulation stage, when continuous super-amplitude fluctuation occurs in the output power of the leading molten salt unit and the frequency of the power grid synchronously, the type of the intervention unit is judged according to the fluctuation period characteristics of the frequency of the power grid, if the fluctuation period is smaller than a preset period threshold value, the flywheel unit with the highest response speed is selected for intervention, and if the fluctuation period is larger than or equal to the preset period threshold value, the battery unit with the highest charge state is selected for intervention.
9. The method for collaborative control of grid power of a hybrid energy storage system based on emergency conditions of claim 1, wherein selecting a new master unit from the same type of energy storage units comprises the following steps: When the leading unit is replaced in the same stage, the current leading unit, all the following units currently running and the units with charge states lower than the participation threshold are removed from all the energy storage units with the same type as the leading energy storage in the stage; and sequencing the rest standby units according to the charge states from high to low, and selecting the unit with the first sequencing as a new leading unit.
10. The method for collaborative control of grid power of a hybrid energy storage system based on emergency conditions of claim 9, wherein selecting a new master unit from the same type of energy storage units further comprises: And sending a leading mode activation instruction to the new leading unit, controlling the new leading unit to gradually take over the power output share of the original leading unit, and simultaneously switching the original leading unit into a standby or charging mode, wherein the original following unit continuously keeps the current power output state unchanged.

Description

Hybrid energy storage system power grid power cooperative control method based on emergency working condition Technical Field The invention belongs to the technical field of hybrid energy storage cooperative control, and particularly discloses a hybrid energy storage system power grid power cooperative control method based on emergency working conditions. Background When the generator set is tripped by a fault or the output of new energy is suddenly reduced in the operation of the power grid, the instantaneous shortage of power on the power generation side can be caused, and the frequency of the power grid is further caused to drop suddenly. In the prior art, various hybrid energy storage cooperative control schemes have been proposed, for example, a primary frequency modulation and secondary frequency modulation cooperative control system of a hybrid energy storage coupling wind generating set is disclosed in Chinese patent publication No. CN121216513A, a state sensing module is used for acquiring power grid frequency deviation and frequency change rate, total power demands including inertia response, primary frequency modulation and secondary frequency modulation are synthesized, a dynamic weight distribution strategy based on an S-shaped nonlinear function is adopted for generating dynamic adjustment weights, and the total power needs to be solved and coupled into reference power instructions of power type energy storage and energy type energy storage. Although the scheme realizes smooth transition and energy relay among different types of energy storage to a certain extent, the defects still exist that the first scheme enables the power type energy storage and the energy type energy storage to be in a full-period parallel participation state all the time, and the output proportion is regulated only through dynamic weights, however, the power grid frequency falling process caused by actual power grid faults has obvious stepwise characteristics, the requirements of different stages on the energy storage response speed and the continuous capability are different, and a unified parallel weighting control strategy cannot be used as a leading agent aiming at the energy storage medium which is matched with the most suitable energy storage medium accurately in a specific stage, so that the regulation and control efficiency is reduced. The second and existing schemes mainly focus on macroscopic power distribution of energy storage types, and neglect the fact that the same type of energy storage in engineering practice often consists of a plurality of independent units with dispersed geographic distribution and different charge states in parallel. Because the unit coordination mechanism inside the type is not established, when the power instruction is executed in the prior art, partial units in the cluster are overloaded, and the other partial units are idle, so that the overall output capacity of the cluster is limited. Disclosure of Invention In order to solve the technical problems or at least partially solve the technical problems, the invention provides a hybrid energy storage system grid power cooperative control method based on emergency working conditions. The aim of the invention can be achieved by the technical scheme that the hybrid energy storage system power cooperative control method based on the emergency working condition comprises the step of judging that the hybrid energy storage system power cooperative control method enters the emergency working condition when the detected power grid frequency is lower than the lower limit of the normal range. And acquiring the charge states, the geographic positions and the available power of all the flywheel, the battery and the molten salt energy storage unit, and constructing an energy storage unit characteristic set. The response process of the emergency working condition is divided into a first frequency modulation stage, a second frequency modulation stage and a third frequency modulation stage, and flywheel energy storage, battery energy storage and fused salt heat storage are used as dominant energy storage types in each stage. And selecting a leading unit and a following unit from the characteristic set of the energy storage unit according to the leading energy storage type of the stage in each stage, and preselecting a preparation unit for the subsequent stage. And controlling the coordinated output power of the leading unit and the following unit in the current stage, judging whether other types of energy storage intervention are needed according to the real-time state, and selecting the adaptive unit to intervene in power output when intervention is needed. And when the state of charge of the leading unit is monitored to be reduced in the current stage and the leading right replacement is required to be triggered, selecting a new leading unit from the energy storage units of the same type. And executing each stage in sequence until the power grid