Electric power control system configured with fused salt for heat storage and operation control method

Abstract

The invention discloses an electric power control system with fused salt heat storage and an operation control method. The system comprises a steam turbine, a clutch, a phase modulation unit, a heater, a fused salt heat storage unit, a control unit and a steam generation unit. A rotating shaft of the steam turbine is connected with a rotor of the phase modulation unit through a clutch; the heater is connected with the new energy power generation system to obtain power supply electric energy and heat fused salt in the fused salt heat storage unit; the steam generating unit generates steam through heat energy of fused salt and outputs the steam to the steam turbine to drive the rotating shaft to rotate. The control unit monitors the voltage, frequency and new energy abandoned power of a power grid, and switches the system to a power generation mode or a phase modulation mode according to the monitoring result: in the power generation mode, the heater is controlled to heat fused salt, the clutch is engaged, and the steam generation unit supplies steam to drive the rotating shaft so as to drive the phase modulation unit to generate power and transmit the power to the power grid; in the phase modulation mode, the clutch is disengaged, and the phase modulation unit is controlled to output reactive power to the power grid. The scheme can improve the operation stability of the power grid.

Description

Technical Field

[0001] This invention relates to the field of power grid technology, and in particular to a power control system and operation control method configured with molten salt thermal storage. Background Technology

[0002] In the process of large-scale construction of wind and solar power bases and high-proportion grid connection of new energy sources, the power grid faces serious challenges. Due to the randomness and volatility of new energy output, the grid voltage fluctuates frequently and the voltage frequency stability is insufficient, which seriously threatens the safe operation of the grid.

[0003] To address the aforementioned issues, existing technologies generally equip large-scale energy bases with grid-based energy storage systems. However, while grid-based energy storage systems have potential in terms of voltage support and short-circuit ratio improvement, they still cannot effectively solve the problem of grid voltage fluctuations caused by the randomness of new energy output, which leads to low operational stability of the power grid. Summary of the Invention

[0004] In view of this, this application provides a power control system and operation control method for configuring molten salt thermal storage, the main purpose of which is to solve the technical problem of low operation stability of power grid.

[0005] According to a first aspect of the present invention, a power control system for configuring molten salt thermal storage is provided, the system comprising a heater, a steam turbine, a clutch, a phase-shifting unit, a molten salt thermal storage unit, a steam generating unit, and a control unit, wherein the phase-shifting unit is connected to a power grid for electrical energy interaction with the power grid; The shaft of the steam turbine is connected to the rotor of the phase-adjusting unit via the clutch. When the clutch is engaged, the shaft can drive the rotor to rotate. The heater is connected to an external new energy power generation system to obtain power from the new energy power generation system in order to heat the molten salt stored in the molten salt thermal storage unit based on the power supplied. The steam generating unit is used to generate steam using the thermal energy of the molten salt and output steam to the steam turbine to drive the shaft to rotate; The control unit is configured to perform the following processes: The control unit monitors the grid voltage and voltage frequency of the power grid, as well as the power curtailment of the new energy power generation system; Based on the grid voltage, the voltage frequency, and the abandoned power, the power control system equipped with molten salt thermal storage is controlled to be in power generation mode or phase regulation mode. When the power control system configured with molten salt thermal storage is in power generation mode, the heater is controlled to heat the molten salt, and the clutch is controlled to engage, so that the steam generating unit outputs steam to the steam turbine, so that the rotating shaft drives the rotor of the phase-adjusting unit to rotate, so that the phase-adjusting unit generates electrical energy and transmits electrical energy to the power grid. When the power control system configured with molten salt thermal storage is in phase adjustment mode, the clutch is disengaged and the phase adjustment unit is controlled to output reactive power to the power grid.

[0006] In an optional embodiment, the control unit controls the power control system configured with molten salt thermal storage to be in power generation mode or phase adjustment mode based on the grid voltage, the voltage frequency, and the curtailed power, including: the control unit determines whether the curtailed power exceeds a preset curtailment threshold, and when the curtailed power exceeds the curtailment threshold, determines whether the voltage frequency is within a preset frequency range; when the voltage frequency is within the frequency range, controls the power control system configured with molten salt thermal storage to be in power generation mode.

[0007] In an optional embodiment, during the process of the power control system configured with molten salt thermal storage switching from phase-shifting mode to power generation mode, the control unit controls the heater to heat the molten salt and controls the clutch to engage, including: the control unit controls the amount of steam delivered by the steam generating unit to the cylinder of the steam turbine to control the rotational speed of the shaft to be synchronized with the rotational speed of the rotor of the phase-shifting unit; when the rotational speed of the shaft is synchronized with the rotational speed of the rotor, the clutch is controlled to engage.

[0008] In an optional embodiment, the control unit controls the power control system configured with molten salt thermal storage to be in power generation mode or phase adjustment mode based on the grid voltage, the voltage frequency, and the power curtailment, including: the control unit determines the deviation value between the grid voltage and a preset voltage standard value, and determines whether the deviation value exceeds a preset deviation threshold; when the deviation value exceeds the deviation threshold, the control unit controls the power control system configured with molten salt thermal storage to be in phase adjustment mode.

[0009] In an optional embodiment, during the process of the power control system configured with molten salt thermal storage switching from power generation mode to phase adjustment mode, the control unit controls the clutch to disengage, including: the control unit reduces the amount of steam delivered by the steam generating unit to the cylinder of the steam turbine, so as to reduce the active power output by the phase adjustment unit to the power grid; when the active power drops to zero, the control unit controls the clutch to disengage.

[0010] In an optional embodiment, the phase-shifting unit includes a synchronous condenser, an excitation unit, and a variable frequency start-up unit; the variable frequency start-up unit is used to output adjustable frequency electrical energy to the synchronous condenser to drive the rotor of the synchronous condenser to reach its rated speed; the excitation unit is used to adjust the excitation current flowing into the rotor of the synchronous condenser to control the synchronous condenser to provide reactive power to the power grid by changing the magnetic field strength generated by the rotor; the control unit controls the phase-shifting unit to output reactive power to the power grid, including: the control unit controls the excitation unit to increase the excitation current supplied to the rotor of the synchronous condenser, so that the synchronous condenser increases the reactive power supplied to the power grid.

[0011] In an optional embodiment, when the power control system configured with molten salt thermal storage is in phase-shifting mode, the control unit is further configured to determine whether a transient disturbance occurs in the power grid, and when a transient disturbance occurs in the power grid, control the excitation unit to increase the excitation current supplied to the rotor of the synchronous condenser, so that the synchronous condenser outputs an instantaneous short-circuit current to the power grid to provide transient support to the power grid.

[0012] In an optional embodiment, after the control unit controls the power control system configured with molten salt thermal storage to switch from the power generation mode to the phase adjustment mode, the control unit controls the steam generating unit to deliver a preset flow rate of steam to the cylinder of the steam turbine, so that the shaft of the steam turbine is in an idling state.

[0013] In an optional embodiment, the molten salt thermal storage unit includes a high-temperature molten salt pump, a low-temperature molten salt pump, a high-temperature molten salt storage tank, and a low-temperature molten salt storage tank. The low-temperature molten salt pump is used to pump molten salt from the low-temperature molten salt storage tank to the high-temperature molten salt storage tank via the heater, so that the heater heats the flowing molten salt and increases the temperature of the molten salt flowing into the high-temperature molten salt storage tank. The high-temperature molten salt pump is used to pump molten salt from the high-temperature molten salt storage tank to the low-temperature molten salt storage tank via the steam generating unit, so that the steam generating unit uses the thermal energy of the flowing molten salt to generate steam and outputs steam to the steam turbine to drive the shaft to rotate.

[0014] According to a second aspect of the present invention, an operation control method is provided, which is applied to a control unit in a power control system configured with molten salt thermal storage as described above, the method comprising: The control unit monitors the grid voltage and voltage frequency of the power grid, as well as the power curtailment of the new energy power generation system; Based on the grid voltage, the voltage frequency, and the abandoned power, the power control system equipped with molten salt thermal storage is controlled to be in power generation mode or phase regulation mode. When the power control system configured with molten salt thermal storage is in power generation mode, the heater is controlled to heat the molten salt, and the clutch is controlled to engage, so that the steam generating unit outputs steam to the steam turbine, so that the rotating shaft drives the rotor of the phase-adjusting unit to rotate, so that the phase-adjusting unit generates electrical energy and transmits electrical energy to the power grid. When the power control system configured with molten salt thermal storage is in phase adjustment mode, the clutch is disengaged and the phase adjustment unit is controlled to output reactive power to the power grid.

[0015] This invention provides a power control system and operation control method configured with molten salt thermal energy storage. Through the synergy of molten salt thermal energy storage and phase-shifting unit and intelligent switching between dual modes, the stability of power grid operation is significantly improved. First, by utilizing the reactive power output of the phase-shifting unit in phase-shifting mode, the voltage fluctuations caused by the randomness of new energy output are precisely smoothed, strengthening the stable support for grid voltage and frequency. Second, in power generation mode, the system heats the molten salt by absorbing abandoned new energy power through a heater, and then generates electricity for grid connection through a steam generation unit and a steam turbine. This not only improves the utilization rate of new energy, but also avoids the safety and maintenance problems of separately configuring electrochemical energy storage units, effectively improving the operational stability of the power grid.

[0016] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This figure shows one of the structural schematic diagrams of a power control system configured with molten salt thermal storage provided by an embodiment of the present invention; Figure 2 This is a second schematic diagram of a power control system configured with molten salt thermal storage provided by an embodiment of the present invention; Figure 3 This is shown as a third schematic diagram of a power control system configured with molten salt thermal storage according to an embodiment of the present invention; Figure 4 A flowchart illustrating an operation control method provided by an embodiment of the present invention is shown. Detailed Implementation

[0018] The present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the present application can be combined with each other.

[0019] Currently, the power grid faces serious challenges in the process of large-scale construction of wind and solar power bases and the integration of a high proportion of new energy sources into the grid. The randomness and volatility of new energy output lead to frequent voltage fluctuations and insufficient voltage frequency stability, seriously threatening the safe operation of the power grid. To address these issues, existing technologies commonly deploy grid-based energy storage systems in large energy bases. However, while these systems have potential in terms of voltage support and short-circuit ratio improvement, they still cannot effectively solve the voltage fluctuations caused by the randomness of new energy output, resulting in low operational stability of the power grid.

[0020] To address the aforementioned problems, in one embodiment, such as Figure 1 As shown, a power control system configured with molten salt thermal energy storage is provided. Taking the system connected between a new energy power generation system G and a power grid W as an example, the power control system includes a heater 100, a steam turbine 200, a clutch 300, a phase-shifting unit 400, a molten salt thermal energy storage unit 500, a steam generation unit 600, and a control unit 700. The phase-shifting unit 400 may include a synchronous condenser, which is connected to the power grid W for electrical energy exchange. Here, the control unit 700 can be a computer device, and the new energy power generation system G can be a new energy collection station to enable the system to absorb curtailed wind and solar power. Furthermore, the clutch 300 can be a 3S clutch.

[0021] Specifically, the shaft of the steam turbine 200 is connected to the rotor of the phase-adjusting unit 400 via the clutch 300. When the clutch 300 is engaged, the shaft can drive the rotor to rotate. When the clutch 300 is disengaged, the rotor of the phase-adjusting unit 400 is disengaged from the shaft of the steam turbine 200.

[0022] Furthermore, the heater 100 is connected to an external new energy power generation system G to obtain power from the new energy power generation system G, and to heat the molten salt in the molten salt thermal storage unit 500 based on the power supplied; here, the molten salt thermal storage unit 500 has a molten salt storage tank, and when the new energy power generation system G experiences power curtailment, the heater 100 is used to heat the molten salt in the molten salt thermal storage unit 500 to achieve electro-thermal conversion and storage.

[0023] Furthermore, the steam generating unit 600 is used to generate steam by utilizing the thermal energy of the molten salt in the molten salt thermal storage unit 500, and outputs steam to the cylinder of the steam turbine 200 to drive the shaft of the steam turbine 200 to rotate.

[0024] Furthermore, the control unit 700 is configured to perform the following processes: First, the control unit monitors the grid voltage and voltage frequency of the power grid, as well as the power curtailment of the new energy power generation system; Then, based on the grid voltage, the voltage frequency, and the abandoned power, the power control system configured with molten salt thermal storage is controlled to be in power generation mode or phase regulation mode.

[0025] When the power control system configured with molten salt thermal storage is in power generation mode, the control unit 700 controls the heater 100 to heat the molten salt and controls the clutch 300 to engage, so that the steam generating unit 600 outputs steam to the steam turbine 200, thereby causing the rotating shaft to drive the rotor of the phase-shifting unit 400 to rotate, generating electrical energy and transmitting it to the power grid W. Furthermore, when the power control system configured with molten salt thermal storage is in phase-shifting mode, the control unit 700 controls the clutch 300 to disengage and controls the phase-shifting unit 400 to output reactive power to the power grid.

[0026] Here, a voltage transformer (not shown in the figure) and a frequency sensor (not shown in the figure) can be connected to the W side of the power grid to collect the amplitude and frequency signals of the grid voltage in real time and transmit them to the control unit 700. Simultaneously, communication can be established with the monitoring platform or metering device of the new energy power generation system G to obtain its total power generation and grid-accepted power, and the difference between the two can be calculated to obtain its curtailed power. Specifically, the control unit 700 controls the power control system equipped with molten salt thermal storage to be in either power generation mode or phase-shifting mode based on the grid voltage, the voltage frequency, and the curtailed power, including: First, the control unit 700 determines whether the curtailed power exceeds a preset curtailment threshold, and if the curtailed power exceeds the preset curtailment threshold, determines whether the voltage frequency is within a preset frequency range. Here, the control unit 700 uses the preset curtailment threshold and frequency range. The curtailment threshold can be set based on the demand for renewable energy consumption, the capacity of the molten salt thermal storage unit, and the rated power of the heater to determine whether the scale of curtailment meets the economic and technical conditions for starting the power generation mode. The preset frequency range is determined based on the power grid safety operation standards (such as my country's power frequency of 50Hz ± 0.2Hz) to ensure that mode switching does not affect the stability of the power grid frequency. Specifically, when the curtailed power is detected to exceed this threshold, the control unit first checks whether the power grid voltage frequency is within the preset range.

[0027] Then, when the voltage frequency is within a preset frequency range, the power control system configured with molten salt thermal storage is put into power generation mode. Here, if the voltage frequency is stable, it indicates that the power grid has the capacity to accept new active power. At this time, the control unit 700 starts the power generation mode, using the heater 100 to absorb the waste electricity and heat the molten salt. The molten salt is then generated and fed into the grid via the steam generation unit 600 and the steam turbine 200, which drive the phase adjustment unit 400. This not only utilizes the waste electricity resources but also avoids the power generation output from impacting the grid frequency, ensuring the stable coordinated operation of the system and the grid.

[0028] Furthermore, when the system switches from phase modulation mode to power generation mode, the control unit 700 controls the heater 100 to heat the molten salt and controls the engagement mode of the clutch 300, including: First, the control unit 700 controls the amount of steam supplied by the steam generating unit 600 to the cylinder of the steam turbine 200, thereby synchronizing the rotational speed of the turbine shaft with the rotational speed of the rotor of the phasing unit 400. Specifically, when the control unit 700 starts the power generation mode, it first adjusts the amount of steam supplied by the steam generating unit 600 to the cylinder of the steam turbine 200 to precisely control the rotational speed of the turbine shaft. This speed adjustment is based on the current synchronous speed of the rotor of the phasing unit 400, ensuring that the two speeds are matched in real time.

[0029] Then, when the rotational speed of the shaft is synchronized with the rotational speed of the rotor, the clutch 300 is controlled to engage. Specifically, when it is detected that the rotational speed of the shaft and the rotor are completely synchronized, the control unit 700 drives the clutch 300 to engage, avoiding engagement shock caused by speed difference, ensuring smooth and reliable transmission connection, and ensuring the power generation stability of the subsequent phase adjustment unit 400.

[0030] Furthermore, the method by which the control unit 700 controls the power control system configured with molten salt thermal storage to be in power generation mode or phase regulation mode based on the grid voltage, the voltage frequency, and the abandoned power also includes: First, the control unit 700 determines the deviation between the grid voltage and a preset voltage standard value, and determines whether the deviation exceeds a preset deviation threshold. Here, the voltage standard value can be set based on the rated operating voltage of the power grid. The deviation threshold can be determined by combining the allowable fluctuation range of the grid voltage and the reactive power compensation capability of the phase adjustment unit 400, and is used to determine whether the voltage deviation needs to be corrected by activating the phase adjustment mode.

[0031] Then, when the deviation value exceeds a preset deviation threshold, the power control system configured with molten salt thermal storage is put into phase adjustment mode. Specifically, when the control unit 700 detects that the deviation value between the grid voltage and the standard value exceeds the deviation threshold, the control unit 700 switches the system to phase adjustment mode: by disengaging the clutch 300, the phase adjustment unit 400 is made to operate independently, and then its output or absorption of reactive power is controlled to quickly compensate for voltage deviation, suppress voltage fluctuations caused by fluctuations in new energy output, ensure that the grid voltage is stable within the safe operating range, and avoid voltage anomalies affecting the operational safety of power equipment and systems.

[0032] Furthermore, when the system switches from the power generation model to the phase adjustment mode, the control unit 700 controls the disengagement of the clutch in the following ways: First, the control unit 700 reduces the amount of steam supplied by the steam generating unit to the cylinder of the steam turbine 200, thereby reducing the active power output of the phasing unit 400 to the power grid G. Specifically, when switching to phasing mode, the control unit 700 can first reduce the amount of steam supplied by the steam generating unit 600 to the cylinder of the steam turbine 200, thus reducing the rotational speed of the shaft and gradually reducing the active power output of the phasing unit 400 to the power grid. This ensures a smooth and controllable adjustment process, preventing sudden changes in active power from impacting the power grid.

[0033] Then, when the active power drops to zero, the clutch 300 is disengaged. Specifically, when the active power output by the phase-shifting unit 400 to the power grid W is detected to drop to zero, the control unit 700 drives the clutch 300 to disengage, ensuring that the disengagement action is performed in a state of no power transmission, protecting the clutch 300 and transmission components, and preparing for the phase-shifting unit 400 to independently output reactive power and stabilize the grid voltage.

[0034] The power control system with molten salt thermal energy storage provided in this embodiment significantly improves the stability of the power grid operation through the synergy of molten salt thermal energy storage and phase-shifting unit and intelligent dual-mode switching: First, by utilizing the reactive power output of the phase-shifting unit in phase-shifting mode, the voltage fluctuations caused by the randomness of new energy output are precisely smoothed, strengthening the stable support for grid voltage and frequency; Second, in power generation mode, the system heats the molten salt by absorbing the abandoned new energy power through a heater, and then generates electricity for grid connection through a steam generation unit and a steam turbine driving the phase-shifting unit. This not only improves the utilization rate of new energy, but also avoids the safety and maintenance problems of separately configuring electrochemical energy storage units, effectively improving the operational stability of the power grid.

[0035] In an optional embodiment, such as Figure 2As shown, the molten salt thermal storage unit includes a high-temperature molten salt pump 510, a low-temperature molten salt pump 520, a high-temperature molten salt storage tank 530, and a low-temperature molten salt storage tank 540; further, the phase adjustment unit includes a synchronous condenser 410, an excitation unit 420, and a frequency converter start-up unit 430; further, the steam turbine 200 includes a high-pressure cylinder 210 and a medium- and low-pressure cylinder 220, with the shafts of the high-pressure cylinder 210 and the medium- and low-pressure cylinder 220 being coaxial; further, the steam generation unit 600 includes a superheater 610, a steam generator 620, a preheater 630, and a reheater 640. Further, the power control system configured with molten salt thermal storage also includes a water circulation unit, which includes a high-pressure heater 810, a low-pressure heater 820, a deaerator 830, a condenser 840, a first feedwater pump 850, and a second feedwater pump 860.

[0036] Specifically, the cryogenic molten salt storage tank 540, cryogenic molten salt pump 520, heater 100, high-temperature molten salt storage tank 530, high-temperature molten salt pump 510, superheater 610, steam generator 620, and preheater 630 are sequentially connected via molten salt pipelines. The preheater 630 is connected to the cryogenic molten salt storage tank 540 via a molten salt pipeline, allowing hot salt to circulate among these components. Furthermore, the high-temperature molten salt storage tank 530 is connected to the reheater 640 via a molten salt pipeline, and the reheater 640 is connected to the molten salt pipeline between the superheater 610 and the steam generator 620 via a molten salt pipeline. Here, the molten salt pipeline can be a high-temperature resistant pipe.

[0037] Furthermore, the steam generator 620 is connected to the superheater 610 via a steam pipeline, the superheater 610 is connected to the high-pressure cylinder 210 via a steam pipeline, the high-pressure cylinder 210 is connected to the reheater 640 and the high-pressure heater 810 via a steam pipeline, so that the steam in the high-pressure cylinder 210 can be delivered to the reheater 640 and the high-pressure heater 810; the reheater 640 is connected to the intermediate-low-pressure cylinder 220 via a steam pipeline, so that the steam output from the reheater 640 can be delivered to the intermediate-low-pressure cylinder 220; the intermediate-low-pressure cylinder 220 is connected to the low-pressure heater 820, the deaerator 830 and the condenser 840 via a steam pipeline, so that the steam output from the intermediate-low-pressure cylinder 220 can be delivered to the low-pressure heater 820, the deaerator 830 and the condenser 840.

[0038] Furthermore, the condenser 840, the first feedwater pump 850, the low-pressure heater 820, and the deaerator 830 are sequentially connected through liquid pipelines, so that the first feedwater pump 850 can pump the condensate from the condenser 840 to the low-pressure heater 820 and the deaerator 830; furthermore, the deaerator 830, the second feedwater pump 860, the high-pressure heater 810, the preheater 630, and the steam generator 620 are sequentially connected through liquid pipelines, so that the second feedwater pump 860 can pump the deaerated condensate output from the deaerator 830 to the high-pressure heater 810, the preheater 630, and the steam generator 620, ultimately enabling the steam generator 620 to evaporate the condensate into steam based on the thermal energy of molten salt, and then deliver the steam to the superheater 610.

[0039] Here, the cryogenic molten salt pump 520 is used to pump the molten salt in the cryogenic molten salt storage tank 540 to the high-temperature molten salt storage tank 530 via the heater 100, so that the heater 100 heats the flowing molten salt and increases the temperature of the molten salt flowing into the high-temperature molten salt storage tank 530; furthermore, the high-temperature molten salt pump 510 is used to pump the molten salt in the high-temperature molten salt storage tank 530 back to the cryogenic molten salt storage tank 540 via the steam generating unit, so that the steam generating unit uses the heat energy of the flowing molten salt to generate steam and outputs steam to the steam turbine to drive the shaft to rotate.

[0040] Furthermore, the variable frequency start-up unit 430 is used to output adjustable frequency electrical energy to the synchronous condenser 410 to drive the rotor of the synchronous condenser 410 to reach the rated speed, so that the synchronous condenser 410 can complete the start-up; furthermore, the excitation unit 420 is used to adjust the excitation current flowing into the rotor of the synchronous condenser 410, so as to control the synchronous condenser 410 to provide reactive power, supply voltage or instantaneous short-circuit current to the power grid by changing the magnetic field strength generated by the rotor.

[0041] Here, when the control unit 700 controls the phase-shifting unit to output reactive power to the power grid G, the control unit 700 can control the excitation unit 420 to increase the excitation current supplied to the rotor of the synchronous condenser 410, so that the synchronous condenser 410 increases the reactive power supplied to the power grid W. Specifically, when the system is in phase-shifting mode, and the grid voltage is lower than a preset standard value, the control unit 700 can send a control command to the excitation unit 420 to drive it to increase the excitation current supplied to the rotor of the synchronous condenser 410, so that the synchronous condenser 410 enters phase-shifting mode. Here, based on the principle of electromagnetic induction and magnetomotive force balance, the increase in excitation current can enhance the rotor magnetic field strength, thereby increasing the inductive reactive power output of the synchronous condenser 410 to the grid, quickly supplementing the magnetic energy gap of the power grid W, offsetting the grid voltage drop, and pushing the grid voltage back to a stable range, ensuring grid voltage stability.

[0042] Furthermore, when the power control system configured with molten salt thermal storage is in phase-shifting mode, the control unit 700 is also used to determine whether a transient disturbance occurs in the power grid W. When a transient disturbance occurs in the power grid W, the control unit 420 increases the excitation current supplied to the rotor of the synchronous condenser, causing the synchronous condenser 410 to output an instantaneous short-circuit current to the power grid W to provide transient support. Specifically, in phase-shifting mode, the control unit 700 can monitor the state of the power grid W in real time to determine whether transient disturbances such as short circuits or voltage drops have occurred. When the control unit 700 detects such disturbances, it can immediately send a control command to the excitation unit 420 to rapidly increase the excitation current supplied to the rotor of the synchronous condenser 410, causing an instantaneous increase in the rotor magnetic field strength. Here, based on the principle of electromagnetic induction, a strong magnetic field will induce a large instantaneous current in the stator winding. This current is injected into the power grid W in the form of an instantaneous short-circuit current, providing transient support for the power grid W, effectively suppressing large voltage drops, and ensuring the transient operational stability of the power grid W.

[0043] The embodiments provided in this application achieve efficient coordination of molten salt thermal storage, steam circulation, and electrical energy interaction by refining the configuration of each system and the connection design of pipelines. Among them, the molten salt circulation system stably completes thermal storage and release. At the same time, the phase adjustment unit is equipped with excitation and frequency conversion start-up modules, which can accurately control reactive power output and grid transient support, significantly improving the power utilization rate and grid operation stability.

[0044] Furthermore, in combination Figure 3 The working process of the power control system configured with molten salt thermal storage is explained as follows: First, when the power control system configured with molten salt thermal energy storage is in the process of curtailed power storage, the curtailed wind and solar power from the new energy power generation system G is first delivered to the heater 100. At the same time, the low-temperature molten salt in the low-temperature molten salt storage tank 540 is pumped into the heater 100 by the low-temperature molten salt pump 520. Further, the heater 100 converts electrical energy into heat energy through electric heating and transfers it to the low-temperature molten salt, raising its temperature to a high temperature. The heated high-temperature molten salt is then transported to the high-temperature molten salt storage tank 530 for sealed storage, completing the conversion and storage of "curtailed power to thermal energy".

[0045] Then, when there is a load gap in the power grid W and power generation is permitted, the power control system equipped with molten salt thermal storage is in the process of thermal energy-mechanical energy conversion. At this time, the high-temperature molten salt in the high-temperature molten salt storage tank 530 is pressurized by the high-temperature molten salt pump 510 and then sequentially sent to the superheater 610, steam generator 620 and reheater 640 to transfer the heat energy of the high-temperature molten salt to the working fluid water through heat exchange. In the steam generator 620, the water absorbs heat and vaporizes to produce saturated steam. The saturated steam enters the superheater 610 and becomes high-temperature and high-pressure superheated steam, which is fed into the high-pressure cylinder 210 to drive its shaft to rotate and do work. Further, the low-pressure steam discharged from the high-pressure cylinder 210 is reheated by the reheater 640 and enters the medium and low-pressure cylinder 220 to continue to expand and do work, further converting thermal energy into mechanical energy. After releasing heat, the molten salt cools down and flows back to the low-temperature molten salt storage tank 540, completing the molten salt cycle.

[0046] Meanwhile, the control unit 700 controls the clutch 300 to engage based on the grid status and speed data of the power grid W, so that the mechanical energy of the medium and low pressure cylinder 220 is transferred to the synchronous condenser 410; under the regulation of the excitation unit 420, the synchronous condenser 410 converts the mechanical energy into electrical energy and transmits it to the grid, completing the power generation closed loop of "mechanical energy-electrical energy" conversion.

[0047] Finally, regarding the steam-water circulation, the exhaust steam discharged from the low-pressure cylinder 220 enters the condenser 840, where it releases residual heat through cooling media such as circulating water, condensing the exhaust steam into low-temperature condensate. The condensate is pressurized by the first feedwater pump 850 and then sent to the low-pressure heater 820 to absorb some of the residual heat discharged from the low-pressure cylinder 220 for preheating. Further, the preheated water enters the deaerator 830 to remove dissolved oxygen and prevent equipment corrosion. Further, the deaerated water is further pressurized by the second feedwater pump 860 and sent to the high-pressure heater 810. At the same time, the high-pressure heater 810 can absorb the residual heat discharged from the high-pressure cylinder 210 to continue heating. Finally, the feedwater that reaches the preset temperature is sent back to the steam generator 620 through the preheater 630 to absorb the heat energy of the high-temperature molten salt again to generate steam, forming a closed-loop steam-water circulation of "steam-condensate-feedwater-steam", enabling the system to achieve cascade recovery of residual heat and recycling of the working fluid.

[0048] In an optional embodiment, after the control unit controls the power control system configured with molten salt thermal storage to switch from the power generation mode to the phasing mode, the control unit controls the steam generating unit to deliver a preset flow rate of steam to the cylinder of the steam turbine, so that the steam turbine shaft is in an idling state. The preset flow rate is based on maintaining the steam turbine shaft running unloaded and not driving the phasing unit to generate electricity; its value can be determined according to actual conditions and is also applicable to this embodiment.

[0049] Specifically, such as Figure 3 As shown, after the system switches from power generation mode to phase adjustment mode, the control unit 700 can control the reheater 640 to supply a preset flow rate of steam to the low- and intermediate-pressure cylinder 220 of the steam turbine 200, keeping the shaft in an idling state. The embodiment provided in this application supplies a small amount of steam to the low- and intermediate-pressure cylinder of the steam turbine, keeping the system in a standby state. This avoids equipment damage caused by frequent turbine start-ups and shutdowns, and also allows for rapid response to subsequent mode switching requirements, improving the system's responsiveness.

[0050] Furthermore, embodiments of this application also provide an operation control method, which is applied to a control unit in a power control system configured with molten salt thermal storage as described above. Figure 4 As shown, the method includes: 401. Monitor the grid voltage and voltage frequency of the power grid, as well as the power curtailment of the new energy power generation system.

[0051] 402. Based on the grid voltage, the voltage frequency, and the abandoned power, control the power control system configured with molten salt thermal storage to be in power generation mode or phase regulation mode.

[0052] Specifically, when the power control system configured with molten salt thermal storage is in power generation mode, the heater is controlled to heat the molten salt, and the clutch is controlled to engage, so that the steam generating unit outputs steam to the steam turbine, thereby causing the rotating shaft to drive the rotor of the phase-shifting unit to rotate, so that the phase-shifting unit generates electrical energy and transmits electrical energy to the power grid; when the power control system configured with molten salt thermal storage is in phase-shifting mode, the clutch is controlled to disengage, and the phase-shifting unit is controlled to output reactive power to the power grid.

[0053] The serial numbers in this application are for descriptive purposes only and do not represent the superiority or inferiority of any particular implementation scenario. The above disclosures are merely a few specific implementation scenarios of this application; however, this application is not limited thereto, and any variations conceived by those skilled in the art should fall within the protection scope of this application.

Claims

1. A power control system configured with molten salt thermal storage, characterized in that, The system includes a heater, a steam turbine, a clutch, a phase adjustment unit, a molten salt thermal storage unit, a steam generation unit, and a control unit. The phase adjustment unit is connected to the power grid to exchange electrical energy with the power grid. The shaft of the steam turbine is connected to the rotor of the phase-adjusting unit via the clutch. When the clutch is engaged, the shaft can drive the rotor to rotate. The heater is connected to an external new energy power generation system to obtain power from the new energy power generation system in order to heat the molten salt stored in the molten salt thermal storage unit based on the power supplied. The steam generating unit is used to generate steam using the thermal energy of the molten salt and output steam to the steam turbine to drive the shaft to rotate; The control unit is configured to perform the following processes: The control unit monitors the grid voltage and voltage frequency of the power grid, as well as the power curtailment of the new energy power generation system; Based on the grid voltage, the voltage frequency, and the abandoned power, the power control system equipped with molten salt thermal storage is controlled to be in power generation mode or phase regulation mode. When the power control system configured with molten salt thermal storage is in power generation mode, the heater is controlled to heat the molten salt, and the clutch is controlled to engage, so that the steam generating unit outputs steam to the steam turbine, so that the rotating shaft drives the rotor of the phase-adjusting unit to rotate, so that the phase-adjusting unit generates electrical energy and transmits electrical energy to the power grid. When the power control system configured with molten salt thermal storage is in phase adjustment mode, the clutch is disengaged and the phase adjustment unit is controlled to output reactive power to the power grid.

2. The power control system with molten salt thermal storage according to claim 1, characterized in that, The control unit controls the power control system equipped with molten salt thermal storage to be in generation mode or phase regulation mode based on the grid voltage, the voltage frequency, and the abandoned power, including: The control unit determines whether the power curtailment exceeds a preset power curtailment threshold, and when the power curtailment exceeds the power curtailment threshold, determines whether the voltage frequency is within a preset frequency range; When the voltage frequency is within the frequency range, the power control system that controls the molten salt thermal storage is in power generation mode.

3. The power control system with molten salt thermal storage according to claim 2, characterized in that, During the process of switching from phase-shifting mode to power generation mode in the power control system configured with molten salt thermal storage, the control unit controls the heater to heat the molten salt and controls the clutch engagement, including: The control unit controls the amount of steam delivered by the steam generating unit to the cylinder of the steam turbine, so as to control the rotational speed of the shaft to be synchronized with the rotational speed of the rotor of the phasing unit; When the rotational speed of the shaft is synchronized with the rotational speed of the rotor, the clutch is controlled to engage.

4. The power control system with molten salt thermal storage according to claim 1, characterized in that, The control unit controls the power control system equipped with molten salt thermal storage to be in generation mode or phase regulation mode based on the grid voltage, the voltage frequency, and the abandoned power, including: The control unit determines the deviation between the grid voltage and a preset voltage standard value, and determines whether the deviation exceeds a preset deviation threshold. When the deviation value exceeds the deviation threshold, the power control system configured with molten salt thermal storage is put into phase adjustment mode.

5. The power control system with molten salt thermal storage according to claim 4, characterized in that, During the process of switching from generation mode to phase regulation mode in the power control system configured with molten salt thermal storage, the control unit controls the clutch to disengage, including: The control unit reduces the amount of steam delivered by the steam generating unit to the cylinder of the steam turbine, thereby reducing the active power output by the phasing unit to the power grid. When the active power drops to zero, the clutch is controlled to disengage.

6. The power control system with molten salt thermal storage according to claim 4, characterized in that, The phase modulation unit includes a synchronous condenser, an excitation unit, and a frequency converter start-up unit; The variable frequency start unit is used to output adjustable frequency electrical energy to the synchronous condenser to drive the rotor of the synchronous condenser to reach the rated speed. The excitation unit is used to adjust the excitation current flowing into the rotor of the synchronous condenser, so as to control the synchronous condenser to provide reactive power to the power grid by changing the magnetic field strength generated by the rotor. The control unit controls the phase-shifting unit to output reactive power to the power grid, including: The control unit controls the excitation unit to increase the excitation current supplied to the rotor of the synchronous condenser, so that the synchronous condenser increases the reactive power supplied to the power grid.

7. The power control system with molten salt thermal storage according to claim 6, characterized in that, When the power control system configured with molten salt thermal storage is in phase adjustment mode, the control unit is also used to determine whether the power grid experiences transient disturbances, and when the power grid experiences transient disturbances, control the excitation unit to increase the excitation current supplied to the rotor of the synchronous condenser, so that the synchronous condenser outputs an instantaneous short-circuit current to the power grid to provide transient support to the power grid.

8. The power control system with molten salt thermal storage according to claim 1, characterized in that, After the control unit controls the power control system configured with molten salt thermal storage to switch from the power generation mode to the phase adjustment mode, the control unit controls the steam generating unit to deliver a preset flow rate of steam to the cylinder of the steam turbine so that the shaft of the steam turbine is in an idling state.

9. The power control system with molten salt thermal storage according to claim 1, characterized in that, The molten salt thermal storage unit includes a high-temperature molten salt pump, a low-temperature molten salt pump, a high-temperature molten salt storage tank, and a low-temperature molten salt storage tank; The cryogenic molten salt pump is used to pump the molten salt in the cryogenic molten salt storage tank to the high-temperature molten salt storage tank via the heater, so that the heater heats the flowing molten salt and increases the temperature of the molten salt flowing into the high-temperature molten salt storage tank; The high-temperature molten salt pump is used to pump the molten salt in the high-temperature molten salt storage tank to the low-temperature molten salt storage tank via the steam generating unit, so that the steam generating unit can use the heat energy of the flowing molten salt to generate steam and output steam to the steam turbine to drive the shaft to rotate.

10. An operation control method, characterized in that, The operation control method is applied to a control unit in a power control system configured with molten salt thermal storage as described in any one of claims 1 to 9, the method comprising: The control unit monitors the grid voltage and voltage frequency of the power grid, as well as the power curtailment of the new energy power generation system; Based on the grid voltage, the voltage frequency, and the abandoned power, the power control system equipped with molten salt thermal storage is controlled to be in power generation mode or phase regulation mode. When the power control system configured with molten salt thermal storage is in power generation mode, the heater is controlled to heat the molten salt, and the clutch is controlled to engage, so that the steam generating unit outputs steam to the steam turbine, so that the rotating shaft drives the rotor of the phase-adjusting unit to rotate, so that the phase-adjusting unit generates electrical energy and transmits electrical energy to the power grid. When the power control system configured with molten salt thermal storage is in phase adjustment mode, the clutch is disengaged and the phase adjustment unit is controlled to output reactive power to the power grid.

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