CN114513018B - Output power flexibility regulating system of renewable energy power plant - Google Patents

Output power flexibility regulating system of renewable energy power plant Download PDF

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CN114513018B
CN114513018B CN202210410694.0A CN202210410694A CN114513018B CN 114513018 B CN114513018 B CN 114513018B CN 202210410694 A CN202210410694 A CN 202210410694A CN 114513018 B CN114513018 B CN 114513018B
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power
control
control module
grid
heating
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CN114513018A (en
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肖立业
聂子攀
邱清泉
张京业
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Institute of Electrical Engineering of CAS
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Institute of Electrical Engineering of CAS
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    • 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
    • H02J3/466—Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
    • 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
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H02J3/16—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by adjustment of reactive power
    • 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
    • H02J3/241—The oscillation concerning frequency
    • 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
    • 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
    • H02J3/381—Dispersed generators
    • 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
    • H02J3/48—Controlling the sharing of the in-phase component
    • 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
    • H02J3/50—Controlling the sharing of the out-of-phase component
    • 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
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • 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
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • 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

Abstract

The invention belongs to the technical field of new energy power generation, aims to solve the problems of poor flexibility and low utilization rate of the existing renewable energy power generation system, and particularly relates to an output power flexibility adjusting system of a renewable energy power plant, which comprises a master control center, a coordination control module, a heating control module, a grid-connected current changing control module and a synchronous generator control module: the coordination control module acquires a first instruction based on a control instruction of the master control center and the output power of the power plant; the heating control module controls the heating power through a first control loop and controls the voltage of the direct current bus through a second control loop so as to adjust the transient heating power; the grid-connected current conversion control module adopts droop control based on a preset virtual synchronous machine control algorithm to provide equivalent inertia; the invention solves the defects that the active power regulation of the renewable energy power plant is difficult, the frequency modulation and peak shaving of the power grid can not be carried out and the inertia can not be provided for the power grid, and can realize the flexible output of the renewable energy power plant.

Description

Output power flexibility regulating system of renewable energy power plant
Technical Field
The invention belongs to the technical field of new energy power generation, and particularly relates to an output power flexibility adjusting system of a renewable energy power plant.
Background
In order to achieve the aims of carbon peak reaching in 2030 and carbon neutralization in 2060 years in China, a novel power system needs to be constructed, and renewable energy power generation is used as a main component of a power source in the novel power system. Renewable energy power generation is connected to the power grid through a power electronic device, photovoltaic power generation generally adopts maximum power tracking control in control, the output of a wind power plant is greatly influenced by factors such as wind power, wind speed and wind direction, and the output of the wind power plant has large fluctuation in short time scale and long time scale, so that the active power regulation of the renewable energy power plant responding to the power grid requirement is difficult, primary and secondary frequency modulation cannot be performed, and inertia support is difficult to provide for the power grid through the power electronic device.
In the existing invention and published documents, a part of researches on heat storage are carried out by utilizing abandoned wind and abandoned photoelectric energy, and the stored heat energy is used for industrial steam supply or civil heating, or an additional heat source or steam source is provided for a traditional thermal power plant and is provided for an auxiliary power generation system to work for frequency modulation and peak regulation. The invention and research focus on how to store and utilize the electric energy of abandoned wind and abandoned light, and flexible modification is carried out on a thermal power plant.
Along with the approaching of carbon peak reaching and carbon neutralization time nodes, the traditional thermal power can be replaced by large-scale renewable energy power generation, so that the problem is solved by thermal power flexible transformation completely, the cost is high, and the carbon emission is increased. For this reason, it is necessary to study methods for the direct flexible adaptation of renewable energy power generation, for which the present invention was developed.
Disclosure of Invention
In order to solve the above problems in the prior art, that is, to solve the problems of poor flexibility and low utilization rate of the existing renewable energy power generation system, the invention provides an output power flexibility adjusting system of a renewable energy power plant, which comprises a master control center, a coordination control module, a heating control module, a grid-connected current switching control module and a synchronous generator control module, wherein the coordination control module, the heating control module, the grid-connected current switching control module and the synchronous generator control module are all in signal connection with the master control center.
The coordination control module is configured to obtain a first instruction based on a control instruction of the master control center and the output power of the power plant; the first instruction comprises heating power information of the heating control module, active power information and reactive power information of the grid-connected commutation control module, and active power information and reactive power information of the synchronous generator control module; the system is also configured to monitor active output information and reactive output information of the heating control module, the grid-connected converter control module and the synchronous generator control module in real time.
The heating control module is configured to control the heating power through a first control loop and control the direct current bus voltage through a second control loop to regulate the transient heating power.
The grid-connected commutation control module is configured to provide equivalent inertia based on a preset virtual synchronous machine control algorithm; in addition, droop control is employed for grid frequency and voltage.
The synchronous generator control module is configured to control active output, reactive output, grid frequency and grid voltage, and is in a rotating standby state in real time.
In some preferred embodiments, the first control loop is active control and the heating power is
Figure 59755DEST_PATH_IMAGE001
，
Figure 652411DEST_PATH_IMAGE002
；
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Is the active output of the grid-connected converter device,
Figure 755813DEST_PATH_IMAGE003
in order to equivalently simulate the frequency modulation capacity of the synchronous motor,
Figure 314970DEST_PATH_IMAGE004
the rated capacity of the synchronous motor is equivalently simulated;
the second control loop is voltage control and controls the single frequency modulation power range of the grid-connected commutation control module to be
Figure 420854DEST_PATH_IMAGE005
。
In some preferred embodiments, the power plant has an output of
Figure 141685DEST_PATH_IMAGE006
(ii) a The active control instruction of the coordination control module is
Figure 775929DEST_PATH_IMAGE007
The reactive power control command is
Figure 748564DEST_PATH_IMAGE008
(ii) a Under the working state, the master control center controls the instruction by controlling the heating power
Figure 846970DEST_PATH_IMAGE009
The active power of the grid-connected converter control module, the reactive power of the grid-connected converter control module and the active control instruction of the synchronous generator control module
Figure 863337DEST_PATH_IMAGE010
The reactive power control instruction of the synchronous generator control module
Figure 984876DEST_PATH_IMAGE011
In response to active control commands from the grid
Figure 885836DEST_PATH_IMAGE012
And reactive control instruction
Figure 182957DEST_PATH_IMAGE013
。
In some preferred embodiments, in the active control state of the system,
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(ii) a If it is
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And is
Figure 949290DEST_PATH_IMAGE016
: then
Figure 756709DEST_PATH_IMAGE017
；
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。
In some preferred embodiments, if
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And is
Figure 125877DEST_PATH_IMAGE020
：
Then
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；
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。
In some preferred embodiments, if
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And is
Figure 431907DEST_PATH_IMAGE024
：
Then
Figure 75903DEST_PATH_IMAGE025
；
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。
In some preferred embodiments, if
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And is
Figure 447475DEST_PATH_IMAGE028
：
Then
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；
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。
In some preferred embodiments, in the reactive control state of the system,
Figure 247307DEST_PATH_IMAGE031
；
if it is
Figure 635563DEST_PATH_IMAGE032
：
Then
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。
In some preferred embodiments, if
Figure 122356DEST_PATH_IMAGE034
：
Then
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；
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。
In some preferred embodiments, the system includes a first control mode and a second control mode; the heating control module comprises an electric heating device.
In the first control mode, part of the electric energy of the renewable energy power plant is directly merged into the power grid, and the heating power and the grid-connected power of the power plant are flexibly controlled through the electric heating device.
The system also comprises a heat storage subsystem and a converter transformer device, wherein the heat storage subsystem and the converter transformer device are in signal connection with the master control center.
In a second control mode, the electric energy generated by the renewable energy power plant is directly supplied to the electric heating device or is supplied to the electric heating device through the converter transformer device; in the heat storage subsystem, heat generated by the electric heating device is stored in the heat storage subsystem through a heat exchange system so as to flexibly adjust the power generation output power.
The invention has the beneficial effects that: 1) the invention solves the defects that the active power regulation of the renewable energy power plant is difficult, the frequency modulation and peak regulation of the power grid can not be carried out and the inertia can not be provided for the power grid, and the output characteristic of the renewable energy power plant after the flexibility modification is basically the same as that of thermal power generation.
2) The scheme disclosed by the invention provides a solution combining a renewable energy power plant and heat storage, realizes flexible modification of the renewable energy power plant, has the functions of frequency modulation, peak regulation and power grid inertia increase, and has the advantages of flexible site selection, no influence on ecological environment, low construction and operation cost, short construction period and the like.
Drawings
Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings.
Fig. 1 is a schematic diagram of a first embodiment of the present invention.
Fig. 2 is a schematic diagram of a second embodiment of the present invention.
FIG. 3 is a schematic diagram of the turnkey system of FIG. 2.
Fig. 4 is a schematic diagram of photovoltaic power plant flexibility modification in the present invention.
Description of reference numerals: 101. a photovoltaic power station; 102. a current converting and voltage transforming device; 103. a heating control device; 104. an electric heating device and a heat exchanger; 105. a cold molten salt storage tank; 106. a molten salt pump; 107. a hot-melt salt storage tank; 108. a molten salt pump; 109. a molten salt heat exchanger; 110. a steam turbine; 111. a generator; 112. a transformer; 113. a power grid interface; 114. a condenser; 115. a cooling tower; 116. a condensate pump; 117. a deaerator.
Detailed Description
Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention.
The invention provides an output power flexibility adjusting system of a renewable energy power plant, which comprises a master control center, a coordination control module, a heating control module, a grid-connected current conversion control module and a synchronous generator control module, wherein the coordination control module, the heating control module, the grid-connected current conversion control module and the synchronous generator control module are in signal connection with the master control center.
The coordination control module is configured to obtain a first instruction based on a control instruction of the master control center and the output power of the power plant; the first instruction comprises heating power information of a heating control module, active power information and reactive power information of a grid-connected commutation control module, and active power information and reactive power information of a synchronous generator control module; the system is also configured to monitor the active output information and the reactive output information of the grid-connected converter control module and the synchronous generator control module in real time.
A heating control module configured to control heating power through a first control loop and control the dc bus voltage through a second control loop to regulate transient heating power; wherein the first control loop is active control, and the heating power is
Figure 95363DEST_PATH_IMAGE037
，
Figure 917826DEST_PATH_IMAGE038
；
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For the active output of the grid-connected converter device,
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in order to equivalently simulate the frequency modulation capacity of the synchronous motor,
Figure 646113DEST_PATH_IMAGE040
the rated capacity of the synchronous motor is equivalently simulated; the second control loop is voltage control and controls the single frequency modulation power range of the grid-connected current conversion control module to be
Figure 436215DEST_PATH_IMAGE041
。
The grid-connected current conversion control module is configured to provide equivalent inertia based on a preset virtual synchronous machine control algorithm, and in addition, droop control is adopted for the frequency and the voltage of the power grid; and the synchronous generator control module is configured to control active output, reactive output, grid frequency and grid voltage, and is in a rotating standby state in real time.
The invention is further illustrated by the following examples with reference to the accompanying drawings.
The invention provides an output power flexibility adjusting system of a renewable energy power plant, which comprises a master control center, a coordination control module, a heating control module, a grid-connected current conversion control module and a synchronous generator control module, wherein the coordination control module, the heating control module, the grid-connected current conversion control module and the synchronous generator control module are in signal connection with the master control center.
The coordination control module is configured to obtain a first instruction based on a control instruction of the master control center and the output power of the power plant; the first instruction comprises heating power information of a heating control module, active power information and reactive power information of a grid-connected commutation control module, and active power information and reactive power information of a synchronous generator control module; the system is also configured to monitor the active output information and the reactive output information of the grid-connected converter control module and the synchronous generator control module in real time.
And the heating control module consists of two control loops and is configured to control the heating power through a first control loop and control the direct current bus voltage through a second control loop so as to regulate the transient heating power.
Specifically, the first control loop is active control, and the heating power is
Figure 924965DEST_PATH_IMAGE037
，
Figure 68501DEST_PATH_IMAGE038
Therefore, the flexible adjustment of the power of the direct grid connection of the renewable energy power plant is realized, and the power control requirements of the peak regulation and the secondary frequency regulation on a longer time scale are met; in particular, the amount of the solvent to be used,
Figure 388624DEST_PATH_IMAGE037
for the active output of the grid-connected converter device,
Figure 465472DEST_PATH_IMAGE039
in order to equivalently simulate the frequency modulation capacity of the synchronous motor,
Figure 175939DEST_PATH_IMAGE040
the rated capacity of the synchronous motor is simulated equivalently.
The second control loop is voltage control and controls the single frequency modulation power range of the grid-connected current conversion control module to be
Figure 247800DEST_PATH_IMAGE041
The method is used for controlling the voltage of the direct current bus, the control method can be droop control, and the control of the voltage of the direct current bus indirectly realizes the control of transient heating power, so that the power generation output fluctuation of the renewable energy sources is stabilized, and meanwhile, power support is provided for primary frequency modulation of the grid-connected converter.
The grid-connected current conversion control module is configured to provide equivalent inertia by adopting droop control based on a preset virtual synchronous machine control algorithm; further, the grid-connected current conversion control module adopts constant active power and constant reactive power control, and the instruction and feedback of active power are respectively
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And
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the reactive command and feedback are respectively
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And
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(ii) a Meanwhile, the power grid frequency and the power grid voltage control are added to an active control loop and a reactive control loop, and the command and the feedback of the power grid frequency are respectively
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And
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the command and feedback of the grid voltage are respectively
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And
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similarly, the control method may adopt droop control. Meanwhile, the control module of the grid-connected converter device adopts a virtual synchronous machine control algorithm.
And the synchronous generator control module is configured to control active output, reactive output, grid frequency and grid voltage, and is in a rotating standby state in real time.
Further, the output power of the power plant is
Figure 4272DEST_PATH_IMAGE050
(ii) a The active control instruction of the coordination control module is
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The reactive power control command is
Figure 56859DEST_PATH_IMAGE052
(ii) a Under the working state, the master control center controls the instruction by controlling the heating power
Figure 133268DEST_PATH_IMAGE053
Active power of grid-connected converter control module and grid-connected converter controlReactive power of system module, active control instruction of synchronous generator control module
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Reactive control instruction of synchronous generator control module
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In response to active control commands of the grid
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And reactive control instruction
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(ii) a Coordination control module monitors electric heating power in real time
Figure 323466DEST_PATH_IMAGE058
Synchronous generator reactive power
Figure 342237DEST_PATH_IMAGE059
Active power of synchronous generator
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Reactive power of grid-connected current converter
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Active power of grid-connected converter
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Determining renewable energy power plant pair commands
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And
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to ensure that the instructions can still be tracked for active and reactive in the event of a fault.
In the case where the system is in an active control state,
Figure 178475DEST_PATH_IMAGE014
(ii) a If it is
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And is
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: then the
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；
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。
If it is
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And is
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：
Then
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；
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。
If it is
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And is provided with
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：
Then
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；
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At this time, the frequency modulation capability of the grid-connected inverter device will be affected.
If it is
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And is provided with
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：
Then
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；
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。
When the system is in the reactive power control state,
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；
if it is
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：
Then
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。
If it is
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：
Then
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；
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。
The system comprises a first control mode and a second control mode; the heating control module comprises an electric heating device; in a first control mode, the electric energy generated by the renewable energy power plant is directly supplied to the electric heating device or is supplied to the electric heating device through the converter transformer device; in the heat storage subsystem, heat generated by the electric heating device is stored in the heat storage subsystem through the heat exchange system so as to flexibly adjust the power generation output power.
In a second control mode, part of electric energy of the renewable energy power plant is directly merged into a power grid, and the heating power and the grid-connected power of the power plant are flexibly controlled through the electric heating device; the system also comprises a heat storage subsystem and a converter transformer device, wherein the heat storage subsystem and the converter transformer device are in signal connection with the master control center.
Specifically, the coordination control module is a module for active and reactive coordination control; the heating control module comprises an electric heating device and a control subsystem thereof; the grid-connected current conversion control module comprises a grid-connected current conversion device; the synchronous generator control module includes a synchronous generator.
Referring specifically to fig. 1, the working principle and flow of the output power flexibility modification method of the renewable energy power plant are as follows: the electric energy generated by the photovoltaic power station 101 is subjected to current conversion and voltage transformation through a current conversion and voltage transformation device 102, and is transmitted to the electric heating device and the control subsystem thereof through an alternating current or direct current connecting line; the heating control device 103 controls the electric heating device and the resistance heating power of the heat exchanger 104. The low-temperature molten salt enters the electric heating device and the heat exchanger 104 from the cold molten salt storage tank 105 through the molten salt pump 106 for heating, and enters the hot molten salt storage tank 107 for storage after being changed into high-temperature molten salt. The high-temperature molten salt enters the molten salt heat exchanger 109 from the hot molten salt storage tank 107 through the molten salt pump 108 to heat the condensed water, high-temperature and high-pressure steam is formed to drive the steam turbine power generation system, and the high-temperature molten salt is changed into low-temperature molten salt and then enters the cold molten salt storage tank 105.
The molten salt heat exchanger 109 heats the condensed water into high-temperature and high-pressure steam to drive the turbine 110, the turbine drives the synchronous generator 111 to generate electricity, and the electricity is boosted through the transformer 112 and then is connected to the grid 113. The steam passes through a condenser 114 and a cooling tower 115 after coming out of the steam turbine 110, the steam is changed into water in the cooling tower 115, the water is circulated through a pump 116, and after passing through a deaerator 117, the condensed water enters the next working cycle.
The steam drives the steam turbine to generate power, the steam valve can be adjusted quickly, and the power output of the steam turbine can be adjusted flexibly and used for responding to the quick power output requirement of the primary frequency modulation of the power grid; due to the existence of the heat storage medium, the synchronous generator can also be used for secondary frequency modulation or participate in power grid peak regulation, and meanwhile, the synchronous generator provides inertia support for the power grid.
In the present embodiment, assuming that the average annual utilization hours of photovoltaic power generation is 1500 hours, and the average annual utilization hours of thermal power generation is 4500 hours, the efficiency of heat storage power generation is about 40%.
A600-kilo-watt photovoltaic power station has annual power generation amount of 90 hundred million degrees and average daily power generation amount of 2466 thousand degrees, assuming that one cycle of charging and discharging is carried out every day, heat is stored while heat is released in a daytime heat storage subsystem for power generation, energy corresponding to net stored heat needs to meet the power generation requirement at night, and assuming that the power consumption at night is 1/2 of the power consumption at all days, the net stored energy is about 1300 thousand degrees. The conversion efficiency of heat to electricity is considered to be 40%, the actual daily power generation is 987 kilo-watt, the annual power generation is 36 hundred million degrees, and the energy consumption is equivalent to a thermal power plant with 100 kilo-watt.
The embodiment of the output power flexibility modification scheme of the renewable energy power plant is as follows: the photovoltaic power plant has 600 ten thousand kilowatts, the heating device has a rated power of 600 ten thousand kilowatts, the heat storage subsystem stores energy at 1300 ten thousand degrees (equivalent heat storage amount), and the steam turbine power generation system has a capacity of 100 ten thousand kilowatts. The frequency modulation capacity is calculated according to 10 percent of the capacity of the synchronous generator and is-10 ten thousand kilowatts to 10 ten thousand kilowatts. After the retrofit, the system equates to a 100 kilo kilowatt thermal power plant.
Referring to fig. 2 and fig. 3, since part of the electric energy of the power plant can also be directly incorporated into the power grid, the heating power and the grid-connected power of the power plant can be flexibly controlled by the control subsystem of the electric heating device, the purpose that the power plant participates in primary frequency modulation and peak shaving can be achieved, and the purpose that part of the electric energy is stored in the heat storage medium is achieved. The master control system is responsible for coordinating and controlling the operation of each subsystem, so that the master control system responds to the active and reactive requirements of the power grid. On the basis of the first embodiment, if 1/2 of the power generation capacity of a 600-kilowatt photovoltaic power station is directly connected to the grid, and the efficiency is 90%, the annual power generation capacity of a renewable energy power plant is 58.5 hundred million degrees, which is equivalent to the annual power generation capacity of a 130-kilowatt thermal power plant.
The second embodiment of the output power flexibility modification scheme of the renewable energy power plant is as follows: the capacity of the converter transformer device is 600 ten thousand kilowatts, the rated power of the heating device is 600 ten thousand kilowatts, the grid-connected converter is 150 ten thousand kilowatts, the energy storage subsystem stores 1300 ten thousand kilowatts, and the capacity of the steam turbine power generation system is 100 ten thousand kilowatts. The frequency modulation capacity of the grid-connected converter is-13-ten-thousand kilowatts, the frequency modulation capacity of the synchronous generator is-13-thousand kilowatts, and the maximum range of the total frequency modulation capacity is-23-thousand kilowatts to 23-thousand kilowatts. After modification, the system is equivalent to a thermal power plant with 130 ten thousand kilowatts, the frequency modulation capacity is higher than that of the first embodiment, and the equivalent inertia is also higher than that of the first embodiment.
A grid-connected converter device 201 and a direct current bus capacitor bank 202 are added, the three-terminal flexible direct current network is formed by the converter transformer device 102 and the heating control device 103, and the grid-connected converter device 201 and the synchronous generator 111 are connected to the grid together through a transformer 112. Simulating the power output characteristic of the synchronous generator at the grid-connected side of the grid-connected converter device 201 by flexibly adjusting the absorption power of the heating control device 103; meanwhile, the grid-connected inverter 201 simulates the inertia of the synchronous machine by adopting a control method of a virtual synchronous machine and combining the direct-current bus capacitor bank 202. In addition, a certain proportion of photovoltaic power generation is enabled to be directly connected to the Internet, and the overall efficiency of the system can be improved.
More specifically, the output fluctuation of the photovoltaic power station 101 is stabilized by using the instantaneous power response characteristic of the heating control device 103, so that the grid-connected power of the grid-connected converter device 201 is stable and adjustable; by utilizing the characteristics of the instantaneous power response of the heating control device 103 and the supporting characteristics of the direct-current bus capacitor bank 202, the grid-connected converter device 201 can realize the rapid adjustment of power, thereby completing the requirement of primary frequency modulation of the power grid, and the power adjustment on a longer time scale can respond to the requirements of secondary frequency modulation and peak modulation of the power grid. The grid-connected converter device 201 adopts a virtual synchronous machine control method, and in addition, the direct current bus capacitor bank 202 can provide zero delay power response, so that a grid-side port of the grid-connected converter device 201 has a synchronous machine characteristic, and the equivalent inertia of a renewable energy power plant is continuously increased on the basis of the existing synchronous generator 111.
Referring to fig. 4, a schematic diagram of a third embodiment of the output power flexibility modification method of the renewable energy power plant according to the present invention is shown, the third embodiment comprising: renewable energy power plants 401, 402 and 403 composed of a plurality of photovoltaic power plants and wind power plants, the grid-connected converter device 201 and the heating control device 103 are networked through a direct current or alternating current power grid, and output power flexibility transformation can be performed on the renewable energy power plants.
The invention discloses a method for flexibly transforming the output power of a renewable energy power plant (comprising one or two of a photovoltaic power station and a wind power plant), and belongs to the technical field of new energy power generation. The renewable energy power plant of the system consists of one or two of a photovoltaic power station or a wind power station, and comprises a converter transformer device, an electric heating device and a control subsystem thereof, a heat storage subsystem, a steam turbine power generation and control subsystem thereof and the like. The electric energy generated by the power plant is directly supplied to the electric heating device or supplied to the electric heating device through the converter transformer device; in the heat storage subsystem, heat generated by the electric heating device is stored in a heat storage medium through a heat exchange system; the heat stored in the heat storage subsystem is used for heating water to form steam, the steam drives a steam turbine to generate electricity, and the power generation output power of the steam turbine can be flexibly adjusted by adjusting a steam valve and is used for responding to the rapid power output requirement of primary frequency modulation of a power grid; due to the existence of the heat storage medium, the method can also be used for secondary frequency modulation or participate in power grid peak regulation. Meanwhile, the synchronous generator provides inertia support for the power grid. Because part of the electric energy of the power plant can also be directly merged into the power grid, the heating power and the grid-connected power of the power plant can be flexibly controlled through the control subsystem of the electric heating device, the aims of participating frequency modulation and peak shaving of the power plant can be achieved, and the aim of storing part of the electric energy in the heat storage medium is also achieved. The invention solves the defects that the active power adjustment of the renewable energy power plant is difficult, the frequency modulation and peak regulation of the power grid can not be carried out and the inertia can not be provided for the power grid, and the output characteristic of the renewable energy power plant after the flexibility modification is basically the same as that of thermal power generation.
While the invention has been described with reference to a preferred embodiment, various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention, and particularly, features shown in the various embodiments may be combined in any suitable manner without departing from the scope of the invention. It is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
In the description of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like, which indicate directions or positional relationships, are based on the directions or positional relationships shown in the drawings, which are for convenience of description only, and do not indicate or imply that the devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
The terms "comprises," "comprising," or any other similar term are intended to cover a non-exclusive inclusion, such that a process, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, article, or apparatus.
So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can be within the protection scope of the invention.

Claims (10)

1. The utility model provides a renewable energy power plant's output flexibility governing system, its characterized in that, includes total control center, coordinated control module, heating control module, the control module of change of current of being incorporated into the power networks and synchronous generator control module, coordinated control module, heating control module, the control module of change of current of being incorporated into the power networks, synchronous generator control module all with total control center signal connection:
the coordination control module is configured to obtain a first instruction based on a control instruction of the master control center and the output power of the power plant; the first instruction comprises heating power information of the heating control module, active power information and reactive power information of the grid-connected commutation control module, and active power information and reactive power information of the synchronous generator control module; the system is also configured to monitor active output information and reactive output information of the grid-connected converter control module and the synchronous generator control module in real time;
the heating control module is configured to control heating power through a first control loop and control direct-current bus voltage through a second control loop so as to adjust transient heating power; the first control loop is active control, power regulation of direct grid connection of a power plant is carried out on the basis of heating power, and secondary frequency modulation and peak shaving of a power grid are responded on a long-time scale; the second control loop is voltage control, output fluctuation of a power plant is stabilized through the instantaneous power response characteristic of the heating control device, stable adjustment of the grid-connected converter device on-line power is achieved, quick adjustment of the grid-connected converter device power is achieved through the instantaneous power response characteristic of the heating control device and the support characteristic of the direct-current bus capacitor bank, and primary frequency modulation of a power grid is completed;
the grid-connected commutation control module is configured to provide equivalent inertia based on a preset virtual synchronous machine control algorithm by adopting droop control; the network side port of the grid-connected converter device has the characteristics of a synchronous machine through zero delay power response of a direct-current bus capacitor;
the synchronous generator control module is configured to control active output, reactive output, grid frequency and grid voltage, and is in a rotating standby state in real time.
2. The renewable energy power plant output power flexibility regulation system of claim 1, wherein the active control, heating power is
Figure 21773DEST_PATH_IMAGE001
，
Figure 854600DEST_PATH_IMAGE002
；
Figure 222696DEST_PATH_IMAGE001
For the active output of the grid-connected converter device,
Figure 140974DEST_PATH_IMAGE003
in order to equivalently simulate the frequency modulation capacity of the synchronous motor,
Figure 41934DEST_PATH_IMAGE004
the rated capacity of the synchronous motor is equivalently simulated;
the voltage control controls the single frequency modulation power range of the grid-connected current conversion control module to be
Figure 729267DEST_PATH_IMAGE005
。
3. The renewable energy power plant output power flexibility adjustment system of claim 2, wherein the power plant output power is
Figure 808213DEST_PATH_IMAGE006
；
The active control instruction of the coordination control module is
Figure 948207DEST_PATH_IMAGE007
The reactive power control command is
Figure 856120DEST_PATH_IMAGE008
；
Under the working state, the master control center controls the instruction by controlling the heating power
Figure 397960DEST_PATH_IMAGE009
The active power of the grid-connected converter control module, the reactive power of the grid-connected converter control module and the active control instruction of the synchronous generator control module
Figure 162654DEST_PATH_IMAGE010
Reactive power control instruction of the synchronous generator control module
Figure 540676DEST_PATH_IMAGE011
In response to active control commands from the grid
Figure 986701DEST_PATH_IMAGE012
And reactive control instruction
Figure 383048DEST_PATH_IMAGE013
。
4. The renewable energy power plant output power flexibility regulation system of claim 3, wherein, while the system is in active control,
Figure 318642DEST_PATH_IMAGE014
；
if it is
Figure 433229DEST_PATH_IMAGE015
And is provided with
Figure 417366DEST_PATH_IMAGE016
：
Then
Figure 684530DEST_PATH_IMAGE017
；
Figure 791026DEST_PATH_IMAGE018
。
5. The system of claim 4, wherein the system is configured to flexibly adjust the output power of the renewable energy power plant
Figure 392909DEST_PATH_IMAGE019
And is
Figure 180736DEST_PATH_IMAGE020
：
Then
Figure 551675DEST_PATH_IMAGE021
；
Figure 576875DEST_PATH_IMAGE022
。
6. The system of claim 5, wherein the system is configured to adjust the output power flexibility of the renewable energy power plant if the system is used in a wind farm
Figure 400475DEST_PATH_IMAGE023
And is
Figure 788731DEST_PATH_IMAGE024
：
Then
Figure 14176DEST_PATH_IMAGE025
；
Figure 400158DEST_PATH_IMAGE026
。
7. The system of claim 6, wherein the system is configured to adjust the output power flexibility of the renewable energy power plant if the system is used in a wind farm
Figure 524103DEST_PATH_IMAGE027
And is
Figure 450470DEST_PATH_IMAGE028
：
Then
Figure 530422DEST_PATH_IMAGE029
；
Figure 352884DEST_PATH_IMAGE030
。
8. The output power flexibility adjustment system of a renewable energy power plant of claim 7, wherein, when the system is in a reactive control state,
Figure 901808DEST_PATH_IMAGE031
；
if it is
Figure 631867DEST_PATH_IMAGE032
：
Then
Figure 831904DEST_PATH_IMAGE033
。
9. The system of claim 8, wherein the system is configured to adjust the output power flexibility of the renewable energy power plant if the system is used in a wind farm
Figure 622006DEST_PATH_IMAGE034
：
Then
Figure 110756DEST_PATH_IMAGE035
；
Figure 129658DEST_PATH_IMAGE036
。
10. The renewable energy power plant output power flexibility adjustment system of claim 9, wherein the system comprises a first control mode and a second control mode;
the heating control module comprises an electric heating device;
in a first control mode, part of electric energy of a renewable energy power plant is directly merged into a power grid, and the heating power and the grid-connected power of the power plant are flexibly controlled through the electric heating device;
the system also comprises a heat storage subsystem and a converter transformer device, wherein the heat storage subsystem and the converter transformer device are in signal connection with the master control center;
in a second control mode, the electric energy generated by the renewable energy power plant is directly supplied to the electric heating device or is supplied to the electric heating device through the converter transformer device; in the heat storage subsystem, heat generated by the electric heating device is stored in the heat storage subsystem through a heat exchange system so as to flexibly adjust the power generation output power.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108063459A (en) * 2017-12-01 2018-05-22 国网辽宁省电力有限公司 A kind of control method for improving power plant's depth peak modulation capacity
WO2020153896A1 (en) * 2019-01-23 2020-07-30 Climeon Ab Method and system for storing electrical energy in the form of heat and producing a power output using said heat
CN112564130A (en) * 2020-11-30 2021-03-26 东北电力大学 Method for improving stability performance of receiving end system of wind power through flexible direct current grid connection
CN113315151A (en) * 2021-05-28 2021-08-27 北京能高自动化技术股份有限公司 Comprehensive energy peak regulation station and peak regulation method constructed based on phase change energy storage

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108063459A (en) * 2017-12-01 2018-05-22 国网辽宁省电力有限公司 A kind of control method for improving power plant's depth peak modulation capacity
WO2020153896A1 (en) * 2019-01-23 2020-07-30 Climeon Ab Method and system for storing electrical energy in the form of heat and producing a power output using said heat
CN112564130A (en) * 2020-11-30 2021-03-26 东北电力大学 Method for improving stability performance of receiving end system of wind power through flexible direct current grid connection
CN113315151A (en) * 2021-05-28 2021-08-27 北京能高自动化技术股份有限公司 Comprehensive energy peak regulation station and peak regulation method constructed based on phase change energy storage

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