CN110492512B - Control method for frequency modulation or peak regulation mode in optical storage combined system - Google Patents

Control method for frequency modulation or peak regulation mode in optical storage combined system Download PDF

Info

Publication number
CN110492512B
CN110492512B CN201910865608.3A CN201910865608A CN110492512B CN 110492512 B CN110492512 B CN 110492512B CN 201910865608 A CN201910865608 A CN 201910865608A CN 110492512 B CN110492512 B CN 110492512B
Authority
CN
China
Prior art keywords
energy storage
storage battery
soc
peak
frequency modulation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201910865608.3A
Other languages
Chinese (zh)
Other versions
CN110492512A (en
Inventor
丁明
施建雄
潘薇
韩平平
孙浩然
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hefei University of Technology
Original Assignee
Hefei University of Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hefei University of Technology filed Critical Hefei University of Technology
Priority to CN201910865608.3A priority Critical patent/CN110492512B/en
Publication of CN110492512A publication Critical patent/CN110492512A/en
Application granted granted Critical
Publication of CN110492512B publication Critical patent/CN110492512B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/28—Arrangements for balancing of the load in a network by storage of energy
    • H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E70/00—Other energy conversion or management systems reducing GHG emissions
    • Y02E70/30—Systems combining energy storage with energy generation of non-fossil origin

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

The invention discloses a frequency modulation or peak shaving in a light storage combined systemThe mode control method comprises the following steps: 1. setting a peak-shaving charging and discharging time period according to the peak-valley time period of the local load and by combining the photovoltaic output condition; 2. setting an energy storage battery SOC partition; 3. the light-storage combined system detects the power grid frequency f and judges an energy storage operation mode; 4. considering inverter idle capacity constraints; 5. setting the maximum output constraint coefficient lambda of the energy storage batterySOC(ii) a 6. The maximum constraint factor constraint is considered. The invention can make full use of the free capacity of the photovoltaic inverter, so that the photovoltaic power station has the capacity of frequency modulation/peak regulation, and the pressure of a power grid frequency modulation unit and a peak regulation unit is reduced.

Description

Control method for frequency modulation or peak regulation mode in optical storage combined system
Technical Field
The invention relates to the field of control strategies of an optical storage combined system, in particular to a control strategy of the optical storage combined system capable of operating in a frequency modulation mode or a peak modulation mode.
Background
The frequency modulation task of the traditional power grid is mainly undertaken by a thermal power generating unit, the thermal power generating unit gradually quits along with the rapid increase of the proportion of new energy in the power grid, the frequency modulation capacity in the system is rapidly reduced, and the frequency modulation capability of the power grid is reduced. Therefore, renewable energy in the power grid is required to have frequency modulation capability to make up for the capacity of the frequency modulation unit reduced along with the exit of the thermal power unit.
In the aspect of participation of photovoltaic power in power grid frequency modulation, the current research mainly comprises two modes of participation of a photovoltaic power station in power grid frequency modulation alone and participation of a new energy and energy storage combined system in power grid frequency modulation.
In the aspect of a control strategy that the photovoltaic power station solely participates in power grid frequency modulation, the grid-connected photovoltaic power station adopts a power difference value control mode, and the load shedding rate of the photovoltaic power station is changed according to different illumination parameters or power grid frequencies, so that the photovoltaic power station operates at a floating load shedding level and has the capability of adjusting the power grid frequency upwards/downwards. However, the effect of the mode of photovoltaic independent participation in frequency modulation is closely related to the photovoltaic output situation, the frequency modulation mode of reserving photovoltaic output causes light abandonment and poor system economy, and the mode is not suitable to be used as the main frequency modulation mode of the power system in consideration of the fluctuation and randomness of the photovoltaic output. Therefore, the photovoltaic frequency modulation has not been practically popularized and applied.
At present, large-scale energy storage technology has the capacity of power grid frequency modulation, and the application is the typical application of energy storage in the field of electric power, which is closest to commercial operation. Therefore, in the aspect that the new energy and energy storage combined system participates in power grid frequency modulation, the output of the energy storage battery regulation combined system is mainly used for participating in power grid frequency modulation, the new energy system adopts maximum power tracking control, and the energy storage battery reduces the influence of the new energy on the power grid frequency by stabilizing the output power fluctuation of the new energy. The energy storage battery is added in the photovoltaic power station, so that the energy storage battery and the photovoltaic are coordinated and matched to participate in the frequency modulation of the power grid, the problem that the photovoltaic output is uneconomical when the photovoltaic independently participates in the frequency modulation of the power grid, and the reliability of the light storage system participating in the frequency modulation of the power grid is higher compared with the reliability of the light storage system participating in the frequency modulation of the power grid when the photovoltaic independently participates in the frequency modulation of the power grid due to the controllability and.
However, in the existing light storage system, the grid-connected inverter is configured according to the sum of new energy and the maximum output of the energy storage battery, the photovoltaic can be fully generated only when the illumination intensity is strongest at noon, and in addition, the inverter capacity is idle, so that waste is caused. In addition, according to the measured data, in more than 99% of 24 hours, the system frequency is in the frequency modulation dead zone of the optical storage system, and the energy storage battery bearing the frequency modulation function does not act and is in an idle state.
Disclosure of Invention
The invention provides a control method of a frequency modulation or peak regulation mode in a light storage combined system for overcoming the defects in the prior art, so that the idle capacity of an inverter and the idle capacity of an energy storage battery in a frequency modulation dead zone can be fully utilized, a photovoltaic power station has the frequency modulation/peak regulation capacity, and the pressure of a power grid frequency modulation unit and a peak regulation unit is reduced.
The technical scheme adopted by the invention for solving the technical problems is as follows:
the invention relates to a control method of a frequency modulation or peak shaving mode in a light storage combined system, wherein the light storage combined system is characterized in that a photovoltaic battery and an energy storage converter are connected in parallel at the direct current side of a photovoltaic grid-connected inverter through a direct current bus, and the energy storage converter is connected with the energy storage battery; the alternating current side of the photovoltaic grid-connected inverter is boosted through a transformer and then connected to a power grid; the control method is characterized by comprising the following steps:
step 1, setting a peak-shaving charging and discharging time period according to a local load peak-valley period and in combination with a photovoltaic output condition;
step 2, setting a state of charge (SOC) partition of the energy storage battery, so that the energy storage battery still leaves a capacity margin for a frequency modulation mode when the energy storage battery operates in the peak modulation mode;
step 2.1, setting the upper limit of the SOC in the frequency modulation mode as the SOCmaxThe lower limit is SOCmin；
Step 2.2, setting the charging upper limit of the SOC in the peak shaving mode as the SOChighThe lower limit of discharge is SOClowAnd SOCmax>SOChigh>SOClow>SOCmin；
Step 3, the light storage combined system detects the power grid frequency f, enables the frequency deviation delta f to be f-50, and judges whether the frequency deviation delta f exceeds a frequency modulation dead zone [ delta f [ ]min,Δfmax](ii) a If the voltage exceeds the preset value, the energy storage battery is enabled to operate in a frequency modulation mode; otherwise, the energy storage battery is enabled to operate in a peak shaving mode; wherein, Δ fminRepresenting the maximum allowable downward deviation of the grid frequency f, Δ fmaxThe maximum value of the grid frequency f allowed to shift upwards;
step 3.1, if delta f is more than delta fmaxAnd the state of charge SOC belongs to [ SOC ∈ >min,SOCmax]Then the energy storage battery is at rated power PeCharging to participate in frequency modulation, and making primary reference power of the energy storage battery be P'ess＝-Pe；
Step 3.2, if delta f is less than delta fminAnd is loaded withElectric state SOC ∈ [ SOC ]min,SOCmax]Then the energy storage battery is at rated power PeDischarging to participate in frequency modulation, and enabling primary reference power of the energy storage battery to be P'ess＝Pe；
Step 3.3, if delta f is epsilon to [ delta fmin,Δfmax]And the energy storage battery acts according to the peak-shaving charging and discharging time period:
if the current is in the peak-shaving discharging time period, and the state of charge SOC belongs to the SOClow,SOCmax]Then the energy storage battery is in the range of alpha multiplied by PeDischarging to participate in peak regulation, and making primary reference power of the energy storage battery be P'ess＝αPe；
If the charging time is in the peak shaving charging time period, and the state of charge SOC belongs to the SOCmin,SOChigh]Then the energy storage battery is in the range of alpha multiplied by PeCharging to participate in peak regulation, and making the primary reference power of the energy storage battery be P'ess＝-αPe(ii) a Wherein alpha represents the charge-discharge power coefficient of the energy storage battery in the peak regulation mode;
step 4, ensuring the photovoltaic output PpvUnder the condition of all grid connection, the spare capacity P 'of the photovoltaic grid-connected inverter'vscFor use in an energy storage battery, wherein P'vsc＝Pvsc-Ppv，PvscIs inverter maximum capacity, P'vsc≥0；
Step 4.1, when the energy storage battery is charged, the primary reference power P'essIf the charging energy of the energy storage battery is less than 0, the photovoltaic grid-connected inverter has no capacity limit on the charging energy of the energy storage battery;
step 4.2, when the energy storage battery discharges, the primary reference power P'essIf the charging energy of the energy storage battery is more than 0, the charging energy of the energy storage battery is transmitted to a power grid through the photovoltaic grid-connected inverter, and the secondary reference power of the energy storage battery is P ″ess＝min{P′ess,P′vsc}；
Step 5, obtaining the maximum output constraint coefficient lambda of the energy storage battery by using the formula (1)SOC：
Figure GDA0002633959430000031
In the formula (1), SOCβIndicating the set state of charge value;
step 6, the energy storage battery is used for generating the final reference power Pess＝P″ess×λSOCAnd charging and discharging are carried out so as to participate in frequency modulation or peak shaving of the power grid.
Compared with the prior art, the invention has the beneficial effects that:
1. in the control method, the optical storage combination system detects the frequency of the power grid, and the energy storage battery operates in a frequency modulation mode or a peak regulation mode, so that the problem that the conventional photovoltaic power station does not have the frequency modulation or peak regulation capability is solved, the photovoltaic power station can participate in the frequency modulation or peak regulation of the power grid, the installed capacities of the conventional frequency modulation unit and the conventional peak regulation unit in the power grid are reduced, and the stability of the power grid is improved.
2. In the control method, the energy released by the energy storage battery is transmitted to the power grid through the existing photovoltaic grid-connected inverter, and a separate energy storage grid-connected inverter is not required to be additionally arranged, so that the reconstruction steps of the actual photovoltaic power station are simplified, the reconstruction cost is saved, meanwhile, the energy storage battery utilizes the idle capacity of the photovoltaic grid-connected inverter in the photovoltaic power station, and the capacity utilization rate of the existing photovoltaic grid-connected inverter is improved.
The control method of the invention is provided with four types of charge state subareas, namely an energy storage battery forbidden area, a frequency modulation area, a peak-shaving charging area and a peak-shaving discharging area, so that the problems of overcharge and overdischarge of the energy storage battery are avoided, and meanwhile, the energy storage battery always leaves a capacity margin for the frequency modulation mode when operating in the peak-shaving mode, thereby realizing the coordinated operation of the two modes of frequency modulation and peak shaving of the energy storage battery.
The control method of the invention considers the charging and discharging characteristics of the energy storage battery, constructs the energy storage battery maximum output coefficient based on the charge state constraint to constrain the output, so that the energy storage battery can be discharged with small current in a low charge state and charged with small current in a high charge state, thereby solving the problem of insufficient utilization of the capacity of the energy storage battery and prolonging the service life of the energy storage battery.
Drawings
FIG. 1 is a flow chart of a comprehensive control method of the light-storage combined system according to the present invention;
FIG. 2 is a topology structure diagram of an optical storage integrated system according to an embodiment of the present invention;
FIG. 3 is a plot of energy storage state of charge zones in accordance with the present invention;
FIG. 4 is a maximum output constraint coefficient curve of the energy storage battery according to the present invention;
FIG. 5 is a graph of solar radiation intensity in an embodiment of the present invention;
FIG. 6 is a graph of grid frequency fluctuation in an embodiment of the present invention;
FIG. 7a is a graph comparing the combined system output and photovoltaic output in an embodiment of the present invention;
fig. 7b is a state of charge curve of the energy storage battery according to the embodiment of the invention.
Detailed Description
In this embodiment, a topology diagram of the optical storage combined system is shown in fig. 2. The direct current side of the photovoltaic grid-connected inverter is connected with a photovoltaic battery and an energy storage converter in parallel through a direct current bus, and the energy storage converter is connected with the energy storage battery; the alternating current side of the photovoltaic grid-connected inverter is boosted through a transformer and then connected to a power grid; the photovoltaic grid-connected inverter adopts an integrated design, a front-stage DC/DC Boost circuit realizes maximum power tracking control, and a rear-stage DC/AC converter adopts a three-phase full-bridge type DC/AC converter to realize power grid connection; the energy storage converter adopts a DC/DC Boost circuit. A control method of frequency modulation or peak regulation mode in an optical storage combined system is carried out by the following steps:
step 1, setting peak-load charging and discharging time periods of an energy storage battery as shown in table 3 by combining the peak-valley time period of local load with the photovoltaic output condition as shown in table 2;
step 2, setting the SOC partition of the energy storage battery as shown in FIG. 3, so that the energy storage battery still has a capacity margin for the frequency modulation mode when operating in the peak modulation mode;
step 2.1, the battery is damaged by over-charging/over-discharging of the energy storage battery, and in order to avoid the situation, the upper limit of the state of charge SOC in the frequency modulation mode is set to beSOCmaxThe lower limit is SOCminCharging up to the upper limit SOCmaxNo longer charging, discharging to lower limit SOCminNo discharge is generated;
step 2.2, the frequency modulation task of the power grid is prior to the peak regulation task, so that the energy storage battery still has a margin for the frequency modulation mode in the peak regulation mode, and the charging upper limit of the SOC in the peak regulation mode is set to be the SOChighThe lower limit of discharge is SOClowAnd SOCmax>SOChigh>SOClow>SOCmin；
Step 3, the light storage combined system detects the power grid frequency f, enables the frequency deviation delta f to be f-50, and judges whether the frequency deviation delta f exceeds a frequency modulation dead zone [ delta f [ ]min,Δfmax](ii) a If the voltage exceeds the preset value, the energy storage battery is enabled to operate in a frequency modulation mode; otherwise, the energy storage battery is operated in a peak shaving mode; wherein, Δ fminRepresenting the maximum allowable downward deviation of the grid frequency f, Δ fmaxRepresents the maximum value of the grid frequency f allowed to shift upwards;
and 3.1, if the delta f exceeds the frequency modulation dead zone, the energy storage battery acts according to the frequency deviation direction, and in the frequency modulation mode, the energy storage battery absorbs or emits power as much as possible in a short time to support the frequency of the power grid, so that the energy storage battery is set to be charged and discharged at a rated power. On the premise of ensuring no overcharge/overdischarge, the primary reference power and the state of charge of the energy storage battery in the frequency modulation mode are constrained as follows:
if Δ f > Δ fmaxAnd the state of charge SOC belongs to [ SOC ∈ >min,SOCmax]The energy storage battery is rated at the power PeCharging to participate in frequency modulation, and making primary reference power of the energy storage battery be P'ess＝-Pe；
If Δ f < Δ fminAnd the state of charge SOC belongs to [ SOC ∈ >min,SOCmax]The energy storage battery is rated at the power PeDischarging to participate in frequency modulation, and making primary reference power of the energy storage battery be P'ess＝Pe；
Step 3.2, if delta f belongs to [ delta f ∈ ]min,Δfmax]Then energy storage battery rootThe energy storage battery performs actions according to the peak-shaving charging and discharging time period, and the charging and discharging duration of the energy storage battery is in the small level in the peak-shaving mode, so that the energy storage battery can be charged and discharged with small power according to the capacity of the energy storage battery, and the service life of the energy storage battery is prolonged. In actual engineering, when the state of charge constraint is not considered, the alpha times of the rated power of the energy storage battery is usually set as the primary reference power for charging and discharging in the peak regulation mode, wherein alpha represents the charging and discharging power coefficient of the energy storage battery in the peak regulation mode. According to the local load peak-valley time period, a certain capacity margin is reserved for the frequency modulation mode of the energy storage battery on the premise of ensuring that the energy storage battery is not overcharged/overdischarged. Therefore, the primary reference power and the state of charge constraint of the energy storage battery in the peak regulation mode are set as follows:
if the current is in the peak-shaving discharging time period, and the state of charge SOC belongs to the SOClow,SOCmax]Then the energy storage battery is in alpha multiplied by PeParticipating in peak regulation for discharging of primary reference power, and enabling the primary reference power of the energy storage battery to be P'ess＝αPe；
If the charging time is in the peak shaving charging time period, and the state of charge SOC belongs to the SOCmin,SOChigh]Then the energy storage battery is in alpha multiplied by PeCharging the primary reference power to participate in peak shaving, and enabling the primary reference power of the energy storage battery to be P'ess＝-αPe；
Step 4, ensuring the photovoltaic output PpvUnder the condition of all grid connection, the spare capacity P 'of the photovoltaic grid-connected inverter'vscFor use in an energy storage battery, wherein P'vsc＝Pvsc-Ppv，PvscIs the maximum capacity in the event of inverter overload, P'vsc≥0；
Step 4.1, when the energy storage battery is charged, obtaining primary reference power P'essIf the charging energy of the energy storage battery is less than 0, the photovoltaic grid-connected inverter has no capacity limit on the charging energy of the energy storage battery;
step 4.2, when the energy storage battery discharges, obtaining primary reference power P'essIf the charging energy of the energy storage battery is more than 0, the charging energy of the energy storage battery is transmitted to a power grid through the photovoltaic grid-connected inverter, and the secondary reference power of the energy storage battery is P ″ess＝min{P′ess,P′vsc}；
And 5, when the energy storage battery responds to the frequency modulation/peak regulation requirement of the power grid, if the energy storage battery is charged and discharged at constant power, the energy storage battery cannot be fully charged or completely release electric energy, so that the capacity of the energy storage battery is wasted, and economic loss is caused. Therefore, the maximum output constraint coefficient lambda of the energy storage battery should be designed reasonablySOCAnd the energy storage battery participates in frequency modulation/peak shaving of the power grid by using the variable charging and discharging power. Setting the maximum output constraint coefficient lambda of the energy storage batterySOCAs shown in fig. 4;
step 5.1, when the charge state of the energy storage battery is higher (SOC is the same as the SOC (SOC)β,SOCmax]) The energy storage battery is represented by P ″)essDischarging; when the state of charge of the energy storage battery is low after discharging (SOC is equal to the state of charge of the energy storage batterymin,SOCβ]) In order to fully utilize the capacity of the energy storage battery and avoid overdischarge, the energy storage battery is provided with a P ″)essMultiplied by a lambda smaller than 1SOCDischarge is performed, and λSOCThe smaller the state of charge decreases. Obtaining the maximum output constraint coefficient lambda of the energy storage battery in the discharging stage by using the formula (1)SOC：
Figure GDA0002633959430000051
In the formula (1), SOCβIndicating the set state of charge value;
step 5.2, when the state of charge of the energy storage battery is lower (SOC belongs to the SOC [ SOC ∈ ]min,SOCβ]) The energy storage battery is according to P ″)essCharging is carried out when the charging is carried out until the state of charge of the energy storage battery is higher (SOC epsilon (SOC)β,SOCmax]) In order to fully utilize the capacity of the energy storage battery and avoid overcharging, the energy storage battery is provided with a P ″)essMultiplied by a lambda smaller than 1SOCIs charged, and λSOCDecreases as the state of charge increases. Obtaining the maximum output constraint coefficient lambda of the energy storage battery in the charging stage by using the formula (2)SOC：
Figure GDA0002633959430000061
Step 6, the energy storage battery is used for generating the final reference power Pess＝P″ess×λSOCAnd charging and discharging are carried out so as to participate in frequency modulation or peak shaving of the power grid. When the output of the energy storage battery is optimized by the maximum output constraint coefficient, the energy storage battery can be ensured to have the capability of quick response, the capacity of the energy storage battery can be fully utilized, the over-charge/over-discharge of the energy storage battery is avoided, and the service life of the energy storage battery is prolonged.
Example (b):
1. and according to the topological structure and the model parameters of the photovoltaic power station, building a detailed photovoltaic power station model in MATLAB/Simulink software. The topological structure of the photovoltaic power station is shown in figure 2, and the model parameters are shown in table 1.
TABLE 1 model parameters
Installed photovoltaic capacity/kW 30 Rated capacity/Ah of energy storage battery 300
SOC max 95％ SOC min 5％
SOChigh 85％ SOC low 15％
SOC
β 50％ α 0.3
Rated power/kW of energy storage battery 10 Inverter capacity/kVA 30
Overload capability of inverter 10％ Transformer capacity/kVA 50
Low voltage side voltage/V of transformer 220 High-voltage side voltage/V of transformer 380
Ambient temperature/. degree.C 25 Curve of solar illumination FIG. 5
Power grid frequency fluctuation curve FIG. 6 Δfmax/Hz 0.06
Δfmin/Hz -0.06 Network voltage/V 380
2. According to the step 1, when the energy storage battery operates in the peak shaving mode, the charging and discharging time periods of the energy storage battery need to be set according to the local load peak-valley time period, and the load peak-valley time period of a certain province is shown in table 2:
TABLE 2 Peak-valley load periods of a province
Figure GDA0002633959430000071
Because the photovoltaic grid-connected inverter in the photovoltaic power station only supports energy to be transmitted from the photovoltaic side to the power grid side and is a unidirectional inverter, the energy absorbed by the energy storage battery comes from the photovoltaic, the charging and discharging time period of the energy storage battery is set, and the change rule of the illumination intensity is also considered besides the change rule of the load.
Firstly, the charging time period of the energy storage battery is set before the time period from the start of photovoltaic power generation in the morning to the first load peak. In the embodiment, the illumination intensity starts at 6:00, so that the illumination intensity is set to 6:00-9:00 as the charging time period of the energy storage battery.
Secondly, the illumination intensity is 12:00-17:00, the period is a period with more photovoltaic output in one day, and the energy storage battery is set to be charged in the period, which is also a main period for charging the energy storage battery in one day.
And thirdly, setting the energy storage battery to discharge in the load peak period.
Based on this, the energy storage battery is set to operate in the peak shaving mode, and the charging and discharging periods are shown in table 3.
TABLE 3 Charge and discharge periods under peak shaving mode of energy storage battery
Figure GDA0002633959430000072
3. And (5) setting the state of charge subareas of the energy storage battery according to the step 2.
In the control strategy proposed herein, the frequency modulation mode has a higher priority than the peak shaving mode. In order to ensure that the energy storage battery has a capacity margin for the frequency modulation mode in the peak shaving process, the following two conditions are considered when the state of charge of the energy storage battery is partitioned:
(1) in order to avoid the situation that the battery is damaged due to over-charge/over-discharge of the energy storage battery, the charging and discharging state interval of the energy storage battery in the frequency modulation mode is [ 5% and 95% ], the energy storage battery is not charged when the charging reaches the upper limit of 95%, and is not discharged when the discharging reaches the lower limit of 5%.
(2) In order to ensure that the energy storage battery has a capacity margin for the frequency modulation mode in the peak shaving mode, the upper charging limit of the energy storage battery is set to be 85% and the lower discharging limit of the energy storage battery is set to be 15% in the peak shaving mode.
4. According to the step 3, the light storage coordination control system detects the power grid frequency f, enables the delta f to be f-50, and judges whether the delta f is in a frequency modulation dead zone. If the delta f exceeds the frequency modulation dead zone, the energy storage battery operates in a frequency modulation mode at the moment; and if the delta f does not exceed the frequency modulation dead zone, the energy storage battery operates in a peak regulation mode at the moment. When Δ f > 0.06 and at this time SOC ∈ [ 5%, 95%]Charging the energy storage battery with rated power of 10kW to participate in frequency modulation, wherein the primary reference power of the energy storage battery is P'ess-10. If Δ f is less than-0.06, and when SOC is equal to [ 5%, 95%]And the energy storage battery discharges at the rated power of 10kW to participate in frequency modulation, and the primary reference power of the energy storage battery is P'ess10. If Δ f ∈ [ -0.06,0.06]And the energy storage battery acts according to the peak regulation time interval. If the discharge time is in the peak-shaving discharge period, and the SOC belongs to [ 15%, 95%]The energy storage battery is discharged at 3kW to participate in peak regulation, and the primary reference power P 'of the energy storage battery is obtained at the moment'ess3; if the time is in the peak-shaving charging period, and the SOC belongs to [ 5%, 85%]The energy storage battery is charged at 3kW to participate in peak shaving, and the primary reference power P 'of the energy storage battery is obtained at the moment'ess＝-3。
5. According to step 4, the inverter capacity is 30kW and the overload capacity is 10%, i.e. the maximum capacity P under overload condition of the invertervscIn order to ensure that the photovoltaic output can be completely grid-connected, the energy storage battery should utilize the idle capacity P 'of the inverter when participating in frequency modulation/peak shaving'vsc，P′vsc＝33-PpvP 'since the inverter maximum capacity is greater than the photovoltaic full power'vscIs greater than 0. P 'when the energy storage battery is charged'essLess than 0, power no longer throughAnd 4, passing the inverter without considering the capacity limit of the inverter. P 'when the energy storage battery is discharged'essAnd > 0, power is transmitted to the power grid through the inverter, and the maximum capacity limit of the inverter needs to be considered. The secondary reference power P ″' of the energy storage cell is thereforeessIs P ″)ess＝min{P′ess,P′vsc}。
6. According to the step 5, in order to avoid the overcharge/overdischarge of the energy storage battery and fully utilize the capacity of the energy storage battery, the maximum output constraint coefficient lambda of the energy storage battery is setSOC. When the SOC belongs to (50%, 95%)]According to P ″)essDischarging; when the discharge reaches SOC ∈ [ 5%, 50%]In order to fully utilize the capacity of the energy storage battery and avoid overdischarge, the energy storage battery is provided with a P ″)ess×λSOCDischarge is performed, and λSOCThe smaller the SOC decreases. Namely, it is
Figure GDA0002633959430000081
When SOC is within the range of 5 percent and 50 percent]According to P ″)essCharging is carried out until SOC is within the range of 50 percent and 95 percent]In order to fully utilize the capacity of the energy storage battery and avoid overcharging, the energy storage battery is provided with a P ″)ess×λSOCIs charged, and λSOCDecreasing as the SOC rises. Namely, it is
Figure GDA0002633959430000082
Namely, the maximum output constraint coefficient curve of the energy storage battery is shown in fig. 4.
7. According to step 6, the final reference power of the energy storage battery is Pess＝P″ess×λSOC。
And (3) building a model in MATLAB/Simulink, and carrying out simulation operation to obtain a comparison graph of the output of the light storage combined system and the photovoltaic output and an SOC curve of the energy storage battery, as shown in fig. 7a and 7 b.
According to the charging and discharging strategy of the energy storage battery, the energy storage battery does not need to be discharged when the load is in a flat time period between 0:00 and 6:00, and the energy storage battery is not charged because the photovoltaic does not exert force. However, at 0:31:12 and 0:38:24, the grid disturbance causes the frequency to drop to 49.91Hz and rise to 50.09Hz, respectively (FIG. 6). As can be seen from fig. 7a and 7b, when the frequency is 49.91Hz, the energy storage state of charge is 50%, and the energy storage battery discharges with the power of 10kW to participate in frequency modulation; however, when the frequency is higher than 50.06Hz, the energy storage battery cannot be charged to participate in frequency modulation because the photovoltaic has no output.
And 6:00-9:00 is a charging time period, and the energy storage battery is charged. As can be seen from fig. 7a and 7b, the photovoltaic output of 6:00-7:00 is 0.72kW, which is less than the reference power of the energy storage cell of 3kW, so that the energy storage cell is charged with 0.72kW, and the state of charge rises slowly; the photovoltaic output is 4kW, the state of charge of the energy storage battery is 51.5% at 7:00, and the energy storage battery is charged with the power of 2.91kW, so that the state of charge rises rapidly. And under the constraint of the charge state, the charge power is gradually reduced to 2.56kW from 7:00 to 9:00, and the output of the light storage system is gradually increased.
9:00-12:00 is the discharge time period, and it can be seen from fig. 7a and 7b that the state of charge of the energy storage battery is above 50% during the discharge time period, and the energy storage battery is discharged at constant power of 3kW to participate in peak regulation.
As can be seen from FIGS. 7a and 7b, the frequency of 9:31:30 falls to 49.92Hz and exceeds the frequency modulation dead zone, the state of charge of the energy storage battery is 61.5%, and the energy storage battery discharges with the power of 10kW to participate in frequency modulation; the frequency of 9:42:00 is increased to 50.1Hz, the state of charge of the energy storage battery is 59.3 percent, and therefore, the frequency modulation is participated by charging with the power of 8.14 kW; the frequency of 11:12:00 is increased to 50.11Hz, and the state of charge of the energy storage battery is 55 percent at the moment, so that the frequency modulation is participated by charging with the power of 9 kW; the frequency of 11:43:11 falls to 49.89Hz, but the total output of the optical storage system reaches the maximum power of 33kW of the inverter at the moment, and the energy storage battery cannot discharge to participate in frequency modulation.
12:00-17:00 in the charging period, as can be seen from fig. 7a and 7b, the state of charge of the energy storage battery is increased from 52.3% to 73.5% during this period, and is constrained by the charging state, and the charging power of the energy storage battery is decreased from 2.86kW to 1.59 kW.
17:00-22:00 is in the peak-shaving discharging period, and the state of charge of the energy storage battery is more than 50% in the period as can be seen from fig. 7a and 7b, and the energy storage battery is discharged at constant power of 3kW to participate in peak shaving. The frequency of 18:46:48 falls to 49.89Hz and exceeds the frequency modulation dead zone, at the moment, the charge state of the energy storage battery is 65 percent, and therefore, the energy storage battery is discharged with the power of 10kW to participate in frequency modulation; the frequency of 19:48:00 rises to 50.1Hz, and the energy storage battery cannot be charged due to no photovoltaic output at the moment, so the energy storage battery stops discharging at the moment and participates in frequency modulation.

Claims (1)

1. A control method of a frequency modulation or peak shaving mode in a light storage combined system is characterized in that a photovoltaic battery and an energy storage converter are connected in parallel on the direct current side of a photovoltaic grid-connected inverter through a direct current bus, and the energy storage converter is connected with the energy storage battery; the alternating current side of the photovoltaic grid-connected inverter is boosted through a transformer and then connected to a power grid; the control method is characterized by comprising the following steps of:
step 1, setting a peak-shaving charging and discharging time period according to a local load peak-valley period and in combination with a photovoltaic output condition;
step 2, setting a state of charge (SOC) partition of the energy storage battery, so that the energy storage battery still leaves a capacity margin for a frequency modulation mode when the energy storage battery operates in the peak modulation mode;
step 2.1, setting the upper limit of the SOC in the frequency modulation mode as the SOCmaxThe lower limit is SOCmin；
Step 2.2, setting the charging upper limit of the SOC in the peak shaving mode as the SOChighThe lower limit of discharge is SOClowAnd SOCmax>SOChigh>SOClow>SOCmin；
Step 3, the light storage combined system detects the power grid frequency f, enables the frequency deviation delta f to be f-50, and judges whether the frequency deviation delta f exceeds a frequency modulation dead zone [ delta f [ ]min,Δfmax](ii) a If the voltage exceeds the preset value, the energy storage battery is enabled to operate in a frequency modulation mode; otherwise, the energy storage battery is enabled to operate in a peak shaving mode; wherein, Δ fminRepresenting the maximum allowable downward deviation of the grid frequency f, Δ fmaxThe maximum value of the grid frequency f allowed to shift upwards;
step 3.1, if delta f is more than delta fmaxAnd the state of charge SOC belongs to [ SOC ∈ >min,SOCmax]Then the energy storage battery is at rated power PeCharging to participate in frequency modulation, so that the energy storage battery is startedStage reference power of P'ess＝-Pe；
Step 3.2, if delta f is less than delta fminAnd the state of charge SOC belongs to [ SOC ∈ >min,SOCmax]Then the energy storage battery is at rated power PeDischarging to participate in frequency modulation, and enabling primary reference power of the energy storage battery to be P'ess＝Pe；
Step 3.3, if delta f is epsilon to [ delta fmin,Δfmax]And the energy storage battery acts according to the peak-shaving charging and discharging time period:
if the current is in the peak-shaving discharging time period, and the state of charge SOC belongs to the SOClow,SOCmax]Then the energy storage battery is in the range of alpha multiplied by PeDischarging to participate in peak regulation, and making primary reference power of the energy storage battery be P'ess＝αPe；
If the charging time is in the peak shaving charging time period, and the state of charge SOC belongs to the SOCmin,SOChigh]Then the energy storage battery is in the range of alpha multiplied by PeCharging to participate in peak regulation, and making the primary reference power of the energy storage battery be P'ess＝-αPe(ii) a Wherein alpha represents the charge-discharge power coefficient of the energy storage battery in the peak regulation mode;
step 4, ensuring the photovoltaic output PpvUnder the condition of all grid connection, the spare capacity P 'of the photovoltaic grid-connected inverter'vscFor use in an energy storage battery, wherein P'vsc＝Pvsc-Ppv，PvscIs inverter maximum capacity, P'vsc≥0；
Step 4.1, when the energy storage battery is charged, the primary reference power P'essIf the charging energy of the energy storage battery is less than 0, the photovoltaic grid-connected inverter has no capacity limit on the charging energy of the energy storage battery;
step 4.2, when the energy storage battery discharges, the primary reference power P'essIf the charging energy of the energy storage battery is more than 0, the charging energy of the energy storage battery is transmitted to a power grid through the photovoltaic grid-connected inverter, and the secondary reference power of the energy storage battery is P ″ess＝min{P′ess,P′vsc}；
Step 5, obtaining by using the formula (1)Maximum output constraint coefficient lambda of the energy storage batterySOC：
Figure FDA0002633959420000021
In the formula (1), SOCβRepresenting the set state of charge intermediate value;
step 6, the energy storage battery is used for generating the final reference power Pess＝P″ess×λSOCAnd charging and discharging are carried out so as to participate in frequency modulation or peak shaving of the power grid.
CN201910865608.3A 2019-09-12 2019-09-12 Control method for frequency modulation or peak regulation mode in optical storage combined system Active CN110492512B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910865608.3A CN110492512B (en) 2019-09-12 2019-09-12 Control method for frequency modulation or peak regulation mode in optical storage combined system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910865608.3A CN110492512B (en) 2019-09-12 2019-09-12 Control method for frequency modulation or peak regulation mode in optical storage combined system

Publications (2)

Publication Number Publication Date
CN110492512A CN110492512A (en) 2019-11-22
CN110492512B true CN110492512B (en) 2020-10-23

Family

ID=68557940

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910865608.3A Active CN110492512B (en) 2019-09-12 2019-09-12 Control method for frequency modulation or peak regulation mode in optical storage combined system

Country Status (1)

Country Link
CN (1) CN110492512B (en)

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110912169A (en) * 2019-12-03 2020-03-24 国网天津市电力公司 Design method and topological structure of alternating current-direct current micro-grid
CN111293725B (en) * 2020-03-24 2023-07-21 安徽海螺新能源有限公司 Control method of photovoltaic energy storage system combining light storage with stable output
CN111697578B (en) * 2020-06-24 2022-05-10 国网福建省电力有限公司 Multi-target energy storage-containing regional power grid operation control method
CN111769560B (en) * 2020-07-17 2022-01-25 国家电网公司西南分部 Emergency drop risk control method for power system with photovoltaic power generation
CN112085336B (en) * 2020-08-12 2022-07-01 国电南瑞南京控制系统有限公司 Comprehensive capability assessment method and system for thermoelectric generator set in full-clean energy transformation process
CN112054544A (en) * 2020-08-20 2020-12-08 国网浙江省电力有限公司嘉兴供电公司 Household peak regulation response and emergency energy storage equipment and peak regulation method thereof
CN112952875B (en) * 2021-01-26 2023-05-05 广东电网有限责任公司 Protection method, device, equipment and storage medium for user side battery energy storage system
CN113131499A (en) * 2021-04-21 2021-07-16 阳光新能源开发有限公司 Peak clipping valley filling and primary frequency modulation cooperative control method and device
CN113708420A (en) * 2021-07-19 2021-11-26 湖南城市学院 Peak-regulating frequency-modulating cooperative control method under different time scales
CN114069662B (en) * 2021-10-28 2023-06-23 国网湖南省电力有限公司 Energy storage power station active scheduling control method and system with peak regulation and frequency modulation functions
CN114336821A (en) * 2021-12-09 2022-04-12 广东友电新能源科技有限公司 Light storage system control method, control circuit, light storage system and electronic equipment
CN114336675B (en) * 2021-12-14 2024-04-02 阳光新能源开发股份有限公司 Frequency modulation control method and device for optical storage station

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101950992B (en) * 2010-08-13 2012-11-14 国网电力科学研究院 System frequency-modulation service implementation method based on electric automobile charging automatic switching control
CN102891495B (en) * 2012-09-18 2016-01-20 中国电力科学研究院 A kind of battery energy storage system participates in primary frequency regulation of power network optimal control method
CN105826934A (en) * 2016-04-27 2016-08-03 中国电力科学研究院 Method for controlling auxiliary frequency modulation of electric vehicle based on feasible region
CN107069789B (en) * 2017-05-13 2019-08-30 东北电力大学 A kind of energy-storage system control strategy towards power grid AGC frequency modulation
US11014466B2 (en) * 2018-01-12 2021-05-25 Johnson Controls Technology Company Building energy optimization system with battery powered vehicle cost optimization

Also Published As

Publication number Publication date
CN110492512A (en) 2019-11-22

Similar Documents

Publication Publication Date Title
CN110492512B (en) Control method for frequency modulation or peak regulation mode in optical storage combined system
KR101174891B1 (en) Energy storage system and controlling method of the same
KR101173856B1 (en) Apparatus and method of tracking maximum power point, and operating method of grid connected power storage system using the same
US8269374B2 (en) Solar panel power management system and method
KR101146670B1 (en) Energy management system and method for controlling thereof
EP3206276B1 (en) Energy storage system and management method thereof
KR101147202B1 (en) Power storage apparatus
KR101181822B1 (en) Battery management system and method thereof, and power storage apparatus using the same
US20050006958A1 (en) Grid-connected power systems having back-up power sources and methods of providing back-up power in grid-connected power systems
CN110797915B (en) Photovoltaic power station active frequency control method based on energy storage
CN102111018A (en) Energy storage system and method of controlling same
JP2013085459A (en) Power storage system and control method therefor
WO2003034523A1 (en) Home-use fuel cell system
Samson et al. Optimal load sharing strategy in a hybrid power system based on pv/fuel cell/battery/supercapacitor
CN114899913A (en) Battery charging and discharging current control method under off-grid mode of hybrid energy storage inverter
WO2019075879A1 (en) Running mode conversion method for alternating-current/direct-current hybrid microgrid
CN114123449A (en) Independent photovoltaic power generation energy storage system and energy management method
CN109936151B (en) Control method for participating in primary frequency modulation of thermal power generating unit through micro-grid system
CN113794218A (en) Electric motor car decommissioning battery reutilization system based on buck-boost circuit
CN115986787B (en) Island distributed energy storage inversion system and energy management method thereof
KR20150111638A (en) High efficiency battery charge/discharge system and method in grid-tied system
JP6677186B2 (en) DC power supply system
JP6795082B2 (en) DC power supply system
Bampoulas et al. A novel dynamic demand control of an electric vehicle integrated in a solar nanogrid with energy storage
CN113364053B (en) Operation decision method for realizing energy hub comprehensive energy

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant