Method and device for absorbing photovoltaic abandoned electricity through heat storage of deaerator

Abstract

The invention provides a method and a device for absorbing photovoltaic abandoned electricity by utilizing heat storage of a deaerator. According to the method, the photovoltaic power abandoning rate can be effectively reduced, local consumption of the photovoltaic super-generating capacity in the low-load period of the power plant is achieved, waste of clean energy is avoided, meanwhile, heat storage adjustment is achieved through transformation of an existing deaerator, the consumption cost is remarkably reduced, and the operation stability of the system is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic curtailment and power plant thermal system collaborative control, and particularly relates to a method and device for utilizing deaerator heat storage to consume photovoltaic curtailment. BACKGROUND

[0002] Under the background of green and low-carbon continuous promotion, photovoltaic power generation as an important clean energy form, its installed capacity is rising year by year, and is widely used in power systems. In the related art, through the collaborative work of grid dispatching, energy storage system and load regulation, a basic system for photovoltaic power consumption is constructed. Specifically, the system covers the whole process from power generation prediction, power regulation to power transmission, including key links such as inverter control, energy storage charging and discharging management, grid reactive power compensation and the like. With the increasing penetration of renewable energy, how to achieve efficient local consumption of photovoltaic power during periods of limited grid compatibility or insufficient load has become a core issue in the optimization of current power system operation.

[0003] However, in the existing photovoltaic curtailment method, the direct use of lithium battery energy storage or adjustment of unit load does not fully consider the collaborative potential of existing equipment in the power plant, which may result in problems such as high initial investment, system response lag, and decreased grid stability. For example, the cost of lithium battery energy storage system per degree of electricity is as high as 1500-2000 yuan, and the service life is short, the maintenance cost is high, and it is difficult to meet the demand of large-scale application; the traditional load regulation method is limited by the stability of the boiler combustion, and the load variation rate is usually not more than 5% / min, which cannot match the rapid fluctuation of photovoltaic output. In addition, the calling capacity of the standby load in the plant is limited, and only small-scale curtailment can be handled, making it difficult to achieve effective consumption during the noon peak period. The above problems not only affect the utilization rate of photovoltaic power, but also pose a potential risk to the stable operation of the power plant thermal system. SUMMARY

[0004] The present application aims to solve one of the technical problems in the related art to some extent.

[0005] To this end, a first object of the present application is to provide a method for utilizing deaerator heat storage to consume photovoltaic curtailment.

[0006] A second object of the present application is to provide a device for utilizing deaerator heat storage to consume photovoltaic curtailment.

[0007] To achieve the above object, a first aspect of the present application provides a method for utilizing deaerator heat storage to consume photovoltaic curtailment, comprising: S1, real-time monitoring of photovoltaic power generation and plant power consumption, and calculating the difference between the two; S2, when the plant power consumption is less than 105% of the photovoltaic power generation and lasts more than 10 minutes, triggering the deaerator heat storage instruction, adjusting the boiler load to make the plant power consumption equal to 105% of the photovoltaic power generation, and introducing the excess steam turbine exhaust into the deaerator for heat storage; S3, calculating the heat storage volume according to the real-time deaerator liquid level, when the heat storage volume reaches the preset upper limit, triggering the deaerator heat storage suspension instruction, and when the photovoltaic power decreases, triggering the heat storage suspension instruction, restoring the boiler load to the required evaporation amount, and switching the control mode of the deaerator steam inlet damper and the water inlet damper to maintain system stability; S4, when the photovoltaic power generation continuously decreases to be lower than the required plant power consumption, triggering the deaerator heat release instruction, and when the actual plant power consumption is greater than 110% of the photovoltaic power generation, reducing the plant power consumption to be equal to 105% of the photovoltaic power generation by reducing the boiler load, to balance the system energy demand by releasing the heat storage of the deaerator.

[0008] In an embodiment of the present application, the S1 comprises: S11, collecting real-time power data by an intelligent power meter arranged at the photovoltaic grid connection point and the plant power bus, and the sampling frequency is 1 minute; S12, filtering the collected power data by using a sliding average algorithm to eliminate the influence of instantaneous fluctuations on the judgment threshold.

[0009] In an embodiment of the present application, the S2 comprises: S21, judging whether the photovoltaic power generation still shows an upward trend in the next 10 minutes according to a photovoltaic output prediction model, and if so, entering the heat storage preparation state in advance; S22, the boiler load adjustment adopts a PID control algorithm, and the set adjustment rate is not more than 5% of the rated load per minute, to ensure the stability of the boiler combustion.

[0010] In an embodiment of the present application, the S3 comprises: S31, the preset upper limit comprises two levels, triggering the heat storage suspension instruction when the heat storage volume reaches 90%, and triggering the heat storage forced suspension instruction when the heat storage volume reaches 98%; S32, the control mode switching of the deaerator steam inlet damper and the water inlet damper adopts an interlocking mechanism, to ensure that the damper mode switching is not only performed after the completion of the boiler load adjustment.

[0011] In an embodiment of the present application, the S4 comprises: S41, when the deaerator heat storage volume is greater than 10%, gradually reducing the boiler load, and the adjustment rate is not more than 3% of the rated load per minute; S42, if the boiler load target value is reduced to be below 80% of the required evaporation amount, maintaining the boiler load at 80% of the required evaporation amount without further reduction.

[0012] In one embodiment of the present application, further comprising: S5, when the deaerator heat storage volume is less than 2%, a deaerator heat storage start preparation instruction is triggered, the boiler master sets a boiler load increase strategy according to the difference between the current auxiliary power and the photovoltaic power generation, and prepares for the heat storage operation in the next round of photovoltaic over-generation; S6, the preset boiler load increase strategy includes predicting future auxiliary power demand changes according to historical photovoltaic output curves, and after predicting that the photovoltaic will overgenerate, increasing the boiler load in advance so that the load exceeds the demand evaporation, and increasing the unit auxiliary power to 105% of the photovoltaic power generation.

[0013] To achieve the above purpose, the second embodiment of the present application proposes a device for utilizing deaerator heat storage to accommodate photovoltaic abandoned electricity, comprising: A photovoltaic power generation and auxiliary power monitoring module is used to monitor the photovoltaic power generation and auxiliary power in real time, and calculate the difference between them; A deaerator heat storage triggering and load adjustment module is used to trigger a deaerator heat storage instruction when the auxiliary power is less than 105% of the photovoltaic power generation and lasts for more than 10 minutes, trigger a heat storage stop instruction when the photovoltaic power decreases, adjust the boiler load to make the auxiliary power equal to 105% of the photovoltaic power generation, and introduce the excess steam turbine exhaust into the deaerator for heat storage; A heat storage volume calculation and stop control module is used to calculate the heat storage volume in real time according to the deaerator liquid level, trigger a deaerator heat storage stop instruction when the heat storage volume reaches a preset upper limit, restore the boiler load to the demand evaporation, and switch the control mode of the deaerator steam inlet damper and water inlet damper to maintain system stability; A deaerator heat release triggering and load reduction module is used to trigger a deaerator heat release instruction when the photovoltaic power generation continuously decreases to be less than the demand auxiliary power, and when the actual auxiliary power is greater than 110% of the photovoltaic power generation, reduce the boiler load to make the auxiliary power equal to 105% of the photovoltaic power generation, so as to utilize the deaerator to release heat storage to balance the system energy demand.

[0014] The method and device of the embodiment of the present application realize the in-situ accommodation of photovoltaic over-generation, significantly reduce the abandoned electricity rate during the medium and low load period, utilize the existing deaerator equipment for heat storage adjustment, avoid additional energy storage investment, and ensure the stable operation of the power plant thermal system.

[0015] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter in the description. BRIEF DESCRIPTION OF DRAWINGS

[0016] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings of exemplary embodiments of the present application, wherein: Figure 1 A flowchart of a method for utilizing deaerator heat storage to accommodate photovoltaic curtailed power provided by an embodiment of the present application is shown in FIG. 1. Figure 2 A boiler load-plant auxiliary power fitting curve provided by an embodiment of the present application is shown in FIG. 2. Figure 3 A deaerator heat storage-photovoltaic accommodation logic diagram provided by an embodiment of the present application is shown in FIG. 3. Figure 4 A deaerator heat storage suspension process diagram triggered by reaching an upper limit of heat storage provided by an embodiment of the present application is shown in FIG. 4. Figure 5 A deaerator heat storage suspension process diagram triggered by a decrease in photovoltaic power provided by an embodiment of the present application is shown in FIG. 5. Figure 6 A deaerator heat release process diagram provided by an embodiment of the present application is shown in FIG. 6. Figure 7 A deaerator heat release suspension process diagram provided by an embodiment of the present application is shown in FIG. 7. Figure 8 A device structure diagram for utilizing deaerator heat storage to accommodate photovoltaic curtailed power provided by an embodiment of the present application is shown in FIG. 8. DETAILED DESCRIPTION

[0017] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The technical solutions in the embodiments of the present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0018] In order to enable persons skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by persons skilled in the art without creative work should fall within the protection scope of the present application.

[0019] A method and device for utilizing deaerator heat storage to accommodate photovoltaic curtailed power according to an embodiment of the present application will be described below with reference to the accompanying drawings.

[0020] Embodiment 1 Figure 1 A flowchart of a method for utilizing deaerator heat storage to accommodate photovoltaic curtailed power according to an embodiment of the present application is shown in FIG. 1, which includes: Figure 1 S1, real-time monitoring of photovoltaic power generation and plant auxiliary power, and calculation of the difference between the two.

[0021] ​Specifically, in the present application, "monitoring photovoltaic power generation and plant power consumption in real time and calculating the difference between the two" is a key pre-step to realize the control logic of local consumption of photovoltaic curtailed power. This step uses a high-precision electric energy metering device (such as an intelligent electric meter compatible with IEC 61850 standard) deployed at the outlet of the photovoltaic inverter and the plant power bus to synchronously sample and collect photovoltaic power generation (P_pv) and plant power consumption (P_load). The sampling frequency is usually set to 1 second / time to meet the response requirement for fast fluctuation of photovoltaic output. The collected data is transmitted to the central control unit (such as DCS or PLC system) through industrial Ethernet or DCS system interface for real-time processing and analysis.

[0022] This step adopts a closed-loop control strategy. First, a dynamic threshold is set, i.e. when the plant power consumption is less than 105% of the photovoltaic power generation, it is determined that the photovoltaic power is overgenerated, and the pre-warning stage is entered. The setting of this threshold is based on the stability requirement of the power system to ensure that the system will not be unstable due to sudden load changes during the adjustment process. Further, the system introduces a "10-minute delay" mechanism to filter transient fluctuations and improve the robustness of the control logic. If the plant power consumption continues to be lower than the threshold and the photovoltaic power generation shows an upward trend during the delay period, the deaerator heat storage instruction is triggered, and the next stage of load adjustment and heat storage control is entered.

[0023] The system needs to collect and process the following key parameters in real time: photovoltaic power generation (unit: kW), plant power consumption (unit: kW), boiler demand evaporation (unit: t / h), deaerator liquid level (unit: m), deaerator pressure (unit: MPa), etc. Among them, the difference between the plant power consumption and the photovoltaic power generation (ΔP = P_pv - P_load) is the core input variable of the control logic, and its accuracy requirement is ±1%, and the response delay needs to be controlled within 500ms to ensure the system's fast response to photovoltaic fluctuations. Among them, the boiler demand evaporation is defined as the boiler evaporation corresponding to the low-pressure heating load of the user demand. Specifically, under the condition of 1.6MPa steam source heating user steam consumption (i.e. unit low-pressure heating capacity), the real-time calculated boiler evaporation under the boiler demand evaporation, corresponding to the plant power consumption, is the demand plant power consumption.

[0024] This step is mainly deployed in the DCS system of a combined heat and power plant, especially suitable for plants with large photovoltaic installed capacity and obvious plant power load fluctuations. For example, in the actual operation of Huaneng Nanjing Thermal Power Plant, this step realizes a significant reduction in curtailed power rate during the noon photovoltaic peak period (11:00-14:00) through linkage control with deaerator inlet steam and water control valves, effectively improving the utilization rate of clean energy.

[0025] The technical effect of this step is to provide accurate decision basis for subsequent boiler load adjustment and deaerator heat storage / heat release control, thereby realizing the dynamic response mechanism of "excess storage and insufficient release". Through real-time difference calculation, the system can realize efficient consumption of photovoltaic curtailment without relying on external energy storage devices, significantly reduce the waste of clean energy, and improve the economy and environmental protection of the overall operation of the power plant.

[0026] Further, S1 comprises: S11, collecting real-time power data through intelligent electric meters arranged at the photovoltaic grid-connected point and the plant power bus, with a sampling frequency of 1 minute.

[0027] Specifically, the step of "collecting real-time power data through intelligent electric meters arranged at the photovoltaic grid-connected point and the plant power bus, with a sampling frequency of 1 minute" is a key data input link for implementing the photovoltaic curtailment dynamic consumption control logic. In some implementations, this step uses intelligent electric meters with Modbus TCP / IP or DL / T 645-2007 communication protocols, which are respectively deployed at the photovoltaic grid-connected point (i.e., the connection point between the photovoltaic inverter and the plant power system) and the plant power bus (i.e., the main power load access point in the plant), for real-time collection of photovoltaic power (P_pv) and plant power load power (P_load).

[0028] The intelligent electric meter collects three-phase alternating current parameters through high-precision current transformers (CT) and voltage transformers (VT), and outputs active power, reactive power, voltage, current, etc. after internal A / D conversion and digital signal processing. The sampling frequency is set to 1 minute, which meets the recommended standard for photovoltaic system operation monitoring in IEC 61724-1, ensuring the timeliness and accuracy of the data, while taking into account the system communication bandwidth and data processing efficiency. The collected data is processed centrally through the SCADA system or DCS system, serving as input variables for the subsequent control logic.

[0029] The sampling accuracy of the intelligent electric meter should not be less than 0.5S level, meeting the accuracy requirements of GB / T 17215.321-2021 "Alternating Current Energy Meter" for industrial-grade electric meters. The sampling frequency is 1 minute, which means that the system updates the power data every 60 seconds, providing sufficient response time for the control logic, while avoiding data redundancy and system burden caused by high-frequency sampling. In addition, the system also needs to set a power comparison threshold, such as when P_load < 105% P_pv, triggering an overproduction warning. This threshold can be fine-tuned according to the actual plant power fluctuation characteristics.

[0030] At the application scenario level, this step is widely applicable to scenarios where distributed photovoltaic systems are deployed in coal-fired, gas-fired, or combined cycle power plants. Through real-time power data acquisition, the system can determine whether the photovoltaic output is excessive and accordingly initiate the heat storage or heat release process of the deaerator, achieving on-site consumption of photovoltaic curtailment without relying on external grid regulation or additional energy storage devices.

[0031] The technical effect of this step is to provide reliable and real-time power input signals for subsequent closed-loop control logic, which is the basis for implementing the dynamic response mechanism of "excess heat storage and insufficient heat release". Through accurate data acquisition and transmission, the system can quickly identify the imbalance between photovoltaic output and plant power, thereby adjusting the boiler load and deaerator operation mode in a timely manner, significantly improving photovoltaic consumption efficiency and ensuring the stability of the thermal system.

[0032] S12, using a moving average algorithm to filter the collected power data, eliminating the influence of instantaneous fluctuations on the judgment threshold.

[0033] In terms of technical implementation, the moving average algorithm sets a fixed-length window (e.g., 10 minutes) and performs point-by-point weighted average or equal-weighted average processing on photovoltaic output data and plant power data within the window. Specifically, the system collects power data at fixed time intervals (e.g., 1 minute) to form a time series data set. The moving average algorithm calculates the average value of the current time point and the previous 9 time points at each time point as the filtered power value at the current time. This algorithm can effectively smooth out short-term fluctuations caused by weather changes, device instantaneous failures, or measurement noise, improving the stability of power difference judgment.

[0034] The sliding window length is 10 minutes, the sampling frequency is 1 minute / second, and the average calculation method can be equal-weighted moving average or exponential weighted moving average (EWMA), where the exponential weighting method can give higher weight to recent data to enhance the response capability to photovoltaic output trend changes. The filtered power data must meet the error range of ±2% of the original power value to ensure the reliability of the control logic. In addition, the system sets the comparison threshold of plant power and photovoltaic power to 105% and 103% to determine whether to enter the heat storage or termination phase.

[0035] At the application scenario level, this filtering step is deployed in the DCS (Distributed Control System) of the power plant or an independent photovoltaic consumption control module, working in coordination with the deaerator steam and water inlet control valves and the boiler main control system. During the noon period when photovoltaic output changes rapidly, the moving average algorithm can effectively suppress false triggers caused by instantaneous power fluctuations, preventing the deaerator from frequently switching between operation states, thereby prolonging the service life of the equipment and improving the stability of the system.

[0036] In terms of technical effectiveness, this step significantly improves the robustness of power difference judgment, avoids control malfunctions caused by instantaneous disturbances, and ensures that the deaerator performs heat storage or heat release operations at the appropriate time, thereby achieving efficient and stable absorption of photovoltaic curtailment.

[0037] S2, when the plant's power consumption is less than 105% of the photovoltaic power generation and lasts for more than 10 minutes, the deaerator heat storage command is triggered. The boiler load is adjusted so that the plant's power consumption is equal to 105% of the photovoltaic power generation, and the excess turbine exhaust steam is introduced into the deaerator for heat storage.

[0038] Specifically, when the plant's power consumption is less than 105% of the photovoltaic power generation for more than 10 minutes, the system will trigger a deaerator heat storage command. This is one of the key control steps in this invention to achieve on-site consumption of photovoltaic power curtailment. This step is based on the coordinated control of the power plant's thermal and electrical systems. By dynamically adjusting the boiler load and deaerator operating mode, it effectively consumes excess photovoltaic power generation, thereby reducing the curtailment rate and improving the system's operational economy.

[0039] At the technical implementation level, the system first collects real-time data on the power consumption and photovoltaic power generation of the busbar through SCADA or DCS systems and calculates the difference. When the power consumption is lower than 105% of the photovoltaic output for 10 consecutive minutes, the system determines that the photovoltaic power generation is over-generated, triggering a deaerator heat storage command. After receiving this command, the boiler main control system calculates the boiler evaporation required to meet the power consumption of 105% of the photovoltaic output based on a preset load-power consumption mapping model, and uses this value as the boiler target load. The boiler gradually increases the load by adjusting parameters such as fuel quantity, air volume, and feedwater flow rate, so that the power consumption rises to the set threshold, thereby realizing the local consumption of photovoltaic power.

[0040] In one embodiment of the present invention, data on 57 sets of boiler loads (x, t / h) and corresponding hourly average plant power consumption (y, kWh) during the operation of Boiler 1 to Unit 2 in 2024 were selected and plotted as follows: Figure 1 The scatter plot shown is used to obtain a polynomial function through software fitting (goodness of fit R² = 0.9816): y=10 -6 x 4 -0.0018x 3 +0.7746x 2 -134.6x+12813(1) Equation (1) corresponds to Figure 1 The fitting relationship between "boiler load - plant power consumption" provides a basis for subsequent load matching calculations. Figure 1It is evident that when the boiler evaporation rate is above 465 t / h, the rate of increase in plant power consumption accelerates, indicating a slight increase in the deaerator's capacity to absorb excess photovoltaic power. Using the same method, the following fitting curve for equation (2) "boiler load (x, t / h) - heating flow rate (z, t / h)" was obtained, with a goodness of fit R... 2 =0.9892, providing a basis for subsequent load matching calculations. z=0.6884x+13.658.

[0041] Simultaneously, to achieve the heat storage function of the deaerator, the system introduces excess turbine exhaust steam into the deaerator. At this time, the deaerator inlet steam regulating valve switches from "automatically tracking deaerator pressure" to "automatically tracking turbine exhaust steam pressure," ensuring that excess exhaust steam can stably enter the deaerator and mix with makeup water for heating and deaeration. The inlet water regulating valve also switches to "automatically tracking deaerator pressure" mode to maintain the dynamic balance of deaerator liquid level and pressure. During this process, the deaerator liquid level typically rises by 0.2~0.8m, the heat storage temperature is maintained at around 151℃, and the heat storage time is generally 1~3 hours.

[0042] This step is applicable in practical scenarios where peak photovoltaic output (such as midday) overlaps with low-load power plant operation. Especially when there is sufficient sunlight but insufficient power demand from the plant, it can effectively avoid the waste of clean energy caused by inverter shutdown. Through closed-loop control logic, the system can achieve rapid response to photovoltaic fluctuations without adding new energy storage devices. Its adjustment response time can be controlled within 5-10 minutes, which is superior to traditional energy storage systems and grid regulation methods.

[0043] From a technical perspective, this step not only significantly improves photovoltaic (PV) grid integration efficiency—reducing PV curtailment by 54% according to 2024 measured data from Huaneng Nanjing Thermal Power Plant—but also effectively lowers power plant operating costs. Since no additional investment in energy storage systems is required, the total cost of the retrofit is only 1 / 10 of that of chemical battery energy storage. Furthermore, it avoids voltage fluctuations and power quality degradation caused by bidirectional power flow across the grid, enhancing the safety and stability of the system operation.

[0044] Furthermore, S2 includes: S21, based on the photovoltaic output prediction model, determine whether the photovoltaic power generation will continue to rise in the next 10 minutes. If it does, enter the heat storage preparation state in advance.

[0045] This step first relies on the construction and operation of a photovoltaic (PV) output prediction model. This model can employ a time-series-based ARIMA algorithm, LSTM neural network, or a physical-data hybrid model. Input parameters include current PV output, solar irradiance, ambient temperature, cloud cover rate of change, etc., and the output is a predicted PV output value for the next 10 minutes. The prediction model needs to have high time resolution (e.g., within 1 minute) and prediction accuracy (error rate ≤ 5%) to ensure the timeliness and accuracy of control commands. In some implementations, the prediction model can be deployed in the power plant's DCS system or a standalone edge computing unit, interacting with the plant's power consumption monitoring system.

[0046] The system sets a threshold of 105% for comparing plant power consumption with photovoltaic power generation. This means that when the plant power consumption is less than 105% of the photovoltaic output, the system enters an over-generation warning state. Simultaneously, a 10-minute delay mechanism is implemented to filter out instantaneous fluctuations and ensure the stability of the judgment. If the prediction model shows that the photovoltaic output continues to rise within the next 10 minutes (i.e., predicted increase ≥ 0.5%), the system triggers a "thermal storage preparation" command, adjusting the control modes of the deaerator inlet steam and water valves in advance to prepare for subsequent thermal storage operations.

[0047] At the application level, this step is suitable for power plants during periods of low to medium load and when photovoltaic output rises rapidly, such as when a sudden increase in solar irradiance around noon leads to excessive photovoltaic power generation. By entering the heat storage preparation state in advance, the system can effectively shorten the response time, improve the start-up efficiency of the deaerator heat storage process, and avoid the risk of power curtailment due to control delays.

[0048] In terms of technical effectiveness, this step, by introducing a prediction mechanism, achieves a shift from "passive response" to "active prediction," significantly improving the foresight and system stability of photovoltaic power consumption. Its innovation lies in the deep integration of the deaerator's thermal storage function with the photovoltaic prediction model, enabling efficient and low-cost power curtailment consumption without the need for additional energy storage equipment, thus possessing significant engineering practical value.

[0049] S22, the boiler load regulation adopts a PID control algorithm, and the regulation rate is set to not exceed 5% of the rated load / minute to ensure the boiler combustion stability.

[0050] Specifically, in this invention, the boiler load regulation adopts a PID (proportional-integral-derivative) control algorithm. Its core objective is to dynamically adjust the boiler evaporation rate to increase the plant's power load when over-generation of photovoltaic power results in insufficient plant power consumption, thereby achieving local absorption of the abandoned photovoltaic power. This control strategy, through a closed-loop feedback mechanism, responds in real-time to the deviation between photovoltaic output and plant power demand, ensuring the stability and economy of the system operation.

[0051] In some implementations, the input signal to the PID controller is the power difference between the photovoltaic output and the plant's power demand, while the output signal is the boiler load adjustment command. The controller limits the output of the boiler's main control system according to a set adjustment rate (not exceeding 5% of rated load / minute) to prevent problems such as combustion instability, water circulation imbalance, or fluctuations in steam and water parameters caused by excessively rapid load changes. This rate limit complies with the safety requirements for boiler load variation in the "Operating Regulations for Boilers in Thermal Power Plants" (DL / T 1055-2007), ensuring that key parameters such as main steam pressure, temperature, and water level are maintained within allowable ranges during adjustment.

[0052] Furthermore, the PID control parameters (such as proportional gain Kp, integral time Ti, and derivative time Td) need to be tuned according to the actual operating characteristics of the power plant. For example, in the embodiment of Huaneng Nanjing Thermal Power Plant, Kp is set to 0.8-1.2, Ti to 120-180 seconds, and Td to 20-40 seconds to achieve a balance between fast response and system stability. The control cycle is usually set to 10 seconds to ensure timely capture and adjustment of photovoltaic fluctuations.

[0053] This step plays a crucial role in the entire technical solution. By precisely controlling the rate of increase and decrease of boiler load, the deaerator effectively stores heat when photovoltaic power generation is excessive and releases heat when photovoltaic power generation is insufficient, thus achieving a dynamic balance of "storing heat when there is excess and releasing heat when there is insufficient power." Its technical value lies in significantly improving the photovoltaic absorption capacity while avoiding the cost and safety risks caused by frequent equipment start-ups and shutdowns or the addition of new energy storage systems. It has good engineering practicality and prospects for promotion.

[0054] S3 calculates the heat storage volume in real time based on the deaerator liquid level. When the heat storage volume reaches the preset upper limit, it triggers the deaerator heat storage stop command. When the photovoltaic power decreases, it triggers the heat storage stop command, restores the boiler load to the required evaporation rate, and switches the control modes of the deaerator steam inlet regulating valve and water inlet regulating valve to maintain system stability.

[0055] Specifically, in some implementations, when the deaerator liquid level reaches a preset upper limit, the system will trigger a deaerator heat storage stop command to prevent the deaerator from overloading and ensure the safety and stability of the thermal system. The technical principle behind this step is based on real-time calculation of the deaerator's heat storage volume and the switching of dynamic control strategies. Specifically, the deaerator's heat storage volume can be estimated through the correspondence between its liquid level and geometric volume. Typically, a liquid level sensor collects real-time liquid level data, which is then converted using the deaerator's volume-liquid level calibration curve (such as the pressure vessel volume calculation method in the ASME standard). In this invention, when the heat storage volume reaches 90%, the system determines that the deaerator is close to full load. At this time, a heat storage stop command is triggered, restoring the boiler load to the required evaporation rate, i.e., the baseline load value calculated based on the fitting formula between the low-pressure heat user's steam consumption (1.6MPa steam source) and the main steam flow rate. A heat storage stop command is triggered when photovoltaic power decreases.

[0056] Furthermore, to maintain the dynamic balance between system pressure and liquid level, the control modes of the deaerator inlet steam control valve and inlet water control valve need to be switched synchronously. During the heat storage phase, the steam control valve tracks the turbine exhaust pressure, while the inlet water control valve tracks the deaerator liquid level. During the shutdown phase, the steam control valve switches to tracking the deaerator pressure, and the inlet water control valve switches to tracking the deaerator liquid level. This switching process is not only executed after the boiler load drops to the required evaporation rate, ensuring a smooth transition of system parameters and avoiding steam pressure fluctuations or liquid level loss due to sudden changes in control mode. It is understandable that the automatic control mode switching of the control valves is not only executed after the load adjustment is completed. It is also triggered when "heat storage volume ≥ 98%" or "photovoltaic power generation ≤ equal to the required plant power consumption" occurs during the deaerator heat storage process. It is also triggered when "heat storage volume ≤ 2%" occurs during the deaerator heat release process.

[0057] In practical applications, this step is suitable for peak photovoltaic power output periods (such as 12:00-14:00). When photovoltaic over-generation leads to a surplus of plant power, the system utilizes the heat stored in the deaerator for on-site absorption. By setting a 90% heat storage limit, safety hazards caused by excessively high deaerator water levels can be effectively prevented, while ensuring sufficient heat storage space for subsequent heat release processes. The technical advantage of this step is that it enables efficient and low-cost absorption of surplus photovoltaic power without adding new energy storage equipment. Simultaneously, closed-loop control maintains the thermal balance between the boiler and turbine, improving the stability and economy of system operation.

[0058] Furthermore, S3 includes: S31 has two preset upper limits: a heat storage stop command is triggered when the heat storage volume reaches 90%, and a heat storage forced stop command is triggered when it reaches 98%.

[0059] Specifically, in this invention, the "preset upper limit includes two levels: triggering a heat storage stop command when the heat storage volume reaches 90%, and triggering a forced heat storage stop command when it reaches 98%" is one of the key steps in realizing the control logic for on-site consumption of photovoltaic curtailment. Its technical implementation principle is based on a real-time monitoring and graded response mechanism for the heat storage status of the deaerator. In some implementations, this step achieves refined control of the heat storage process by setting two different liquid level thresholds, corresponding to 90% and 98% of the deaerator's heat storage space, respectively, thereby maximizing photovoltaic consumption efficiency while ensuring system safety.

[0060] From a technical perspective, the heat storage volume of the deaerator is calculated by real-time acquisition of its liquid level signal and combined with the deaerator's geometric volume parameters. When the calculated heat storage volume reaches 90%, the control system determines that the deaerator is close to full load and triggers a "heat storage stop command." This involves gradually reducing the boiler load to the "boiler's required evaporation rate" through the boiler main control system to reduce the amount of steam entering the deaerator and prevent the liquid level from rising further. Simultaneously, the control modes of the deaerator's steam inlet valve and water inlet valve also switch accordingly. The steam inlet valve switches from "automatically tracking turbine exhaust pressure" to "automatically tracking deaerator pressure," while the water inlet valve switches from "automatically tracking deaerator pressure" to "automatically tracking deaerator liquid level" to maintain the deaerator's operational stability.

[0061] Furthermore, when the heat storage volume reaches 98%, the system enters a "forced heat storage shutdown" state. At this point, the deaerator is approaching its safe operating limit and the heat storage operation must be stopped immediately. Previously, when the heat storage volume reached 90%, the boiler load target value was already set to the required evaporation rate, and the control modes of the steam inlet regulating valve and the water inlet regulating valve were switched simultaneously. The heat storage volume was close to the upper limit. If a forced shutdown command is triggered, it can ensure that the deaerator heat storage volume does not rise further in time, and ensure that the deaerator does not overflow, pipe vibration, or deterioration of deaeration effect during operation. However, since the boiler load has not yet been reduced to the target load, the excess steam from the turbine is transferred to the heating network, which will cause the turbine back pressure to rise. However, due to the large capacity of the heating network, it has been found in actual operation that the rise in heating network pressure is not enough to cause safety problems. If the turbine back pressure rises to a certain threshold, it can be relieved by opening the turbine exhaust valve or by using the safety valves of the heating network and connected pipelines. This forced shutdown mechanism meets the safety requirements for deaerator level control in ASME standards, while also satisfying the stability requirements of the power plant's thermal system operation.

[0062] In application scenarios, this step is suitable for peak photovoltaic output periods, such as midday. When photovoltaic over-generation leads to insufficient plant power consumption, the excess electricity can be converted and stored on-site through the staged heat storage control of the deaerator. In terms of technical effectiveness, this step effectively prevents deaerator overload operation, ensuring the safety and stability of the thermal system. It also improves the response accuracy of photovoltaic power consumption and the economic efficiency of system operation, making it a crucial element in realizing the "excess power is stored" control strategy.

[0063] S32, the control mode switching of the deaerator steam inlet regulating valve and water inlet regulating valve adopts an interlocking mechanism to ensure that the regulating valve mode switching is not only performed after the boiler load adjustment is completed.

[0064] Specifically, in some implementations, the control mode switching of the deaerator steam inlet control valve and the deaerator water inlet control valve in this invention adopts an interlock mechanism. The technical principle behind this interlock mechanism is based on the coordinated operation of the dynamic response of the thermal system and the control logic. The core of this interlock mechanism is to ensure that the switching of the deaerator control valve's control mode is allowed not only after the boiler load adjustment is completed and the system is operating stably, thereby avoiding system pressure and liquid level fluctuations caused by premature valve switching or unstable load, which could affect the deaerator's operational safety and the stability of the thermal system.

[0065] The specific operation is as follows: When the system enters the deaerator heat storage or release stage, the control logic first sends a load adjustment command to the boiler main control system, requiring the boiler to increase or decrease the load according to the preset target evaporation rate. After receiving the command, the boiler main control system adjusts parameters such as fuel quantity, air volume, and feedwater flow rate. During this process, the system continuously monitors the boiler load change rate to ensure that it does not exceed the maximum allowable load change rate for boiler operation (generally ≤5% of rated load / minute) to maintain combustion stability and steam-water system balance.

[0066] After the boiler load adjustment is completed, the system confirms that the boiler operating status is stable through interlock signals. Only then is the switch between the control modes of the deaerator inlet steam valve and the inlet water valve permitted. For example, during the thermal storage phase, the inlet steam valve switches from "automatically tracking deaerator pressure" to "automatically tracking turbine exhaust pressure," while the inlet water valve switches from "automatically tracking deaerator liquid level" to "automatically tracking deaerator pressure," to achieve a coordinated heating and deaeration process for exhaust steam and makeup water. During the switching process, it is ensured that the boiler load adjustment process is completely finished to avoid valve malfunctions due to unstable load.

[0067] This step plays a crucial role in system coordination and safety assurance within the entire technical solution. Through an interlocking mechanism, it effectively prevents abnormal liquid levels or pressures caused by valve switching in the deaerator before the boiler load has stabilized, thus ensuring the continuity and safety of the thermal system operation. Furthermore, this mechanism enhances the controllability and response accuracy of the photovoltaic curtailment process, ensuring that the deaerator operates under optimal conditions for heat storage or release, thereby improving the overall system's regulation efficiency and energy utilization rate.

[0068] S4. When the photovoltaic power generation continues to drop below the required plant power consumption, the deaerator heat release command is triggered. When the actual plant power consumption is greater than 110% of the photovoltaic power generation, the boiler load is reduced to reduce the plant power consumption to 105% of the photovoltaic power generation, so as to use the deaerator to release stored heat to balance the system energy demand.

[0069] Specifically, when photovoltaic power generation continuously declines below the required plant power consumption, a deaerator heat release command is triggered. This reduces the boiler load so that the plant power consumption equals 105% of the photovoltaic power generation, utilizing the deaerator to release stored heat to balance the system's energy demand. This is contingent on the actual plant power consumption being greater than 110% of the photovoltaic power generation, ensuring there is room for downward adjustment. This step is a key control element in the invention "Method for Utilizing Deaerator Heat Storage to Absorb Wasted Photovoltaic Power," aiming to achieve dynamic energy balance in the system and improve the local absorption efficiency of photovoltaic power.

[0070] This step, based on real-time monitoring system data on photovoltaic power generation and plant power consumption, determines whether to enter the heat release phase by setting a threshold. When photovoltaic power generation is continuously lower than the required plant power consumption and the difference exceeds 10%, the system activates a 10-minute delay mechanism to confirm the persistence of the declining photovoltaic output trend. If this trend is confirmed, the control logic triggers a deaerator heat release command and simultaneously sends a load adjustment signal to the boiler main control system, gradually reducing the boiler load to the evaporation target value corresponding to 105% of the photovoltaic power generation. This target value is calculated using a fitting formula between the main steam flow rate and the low-pressure heating supply, ensuring dynamic matching between plant power consumption and photovoltaic output.

[0071] Boiler load adjustments must meet the requirements for stable operation of the thermal system, with load variation controlled within ≤5% of rated load / minute to avoid system oscillations caused by unstable combustion or sudden changes in turbine steam inlet. Simultaneously, the deaerator must maintain its pressure at approximately 0.4 MPa during heat release, and the deaerator liquid level must be controlled to not fall below 0 mm (the deaerator range is -1300 mm to +1300 mm) to ensure deaeration efficiency and system safety. When the boiler load drops to 80% of the required evaporation capacity, the system will automatically lock this lower load limit to prevent the boiler from operating into an unsafe zone.

[0072] At the application level, this step is suitable for coal-fired or gas-fired power plants operating at low to medium loads, especially after the midday peak of photovoltaic output, when the demand for plant electricity decreases, leading to a surplus of photovoltaic power. By releasing the heat stored in the deaerator, the frequency of photovoltaic inverter shutdowns can be effectively reduced, improving the utilization rate of clean energy while avoiding impacts on the power grid.

[0073] The technical advantage of this step lies in achieving a dynamic balance between photovoltaic power and plant power consumption through closed-loop control. This allows the system to effectively cope with photovoltaic fluctuations without the need for additional energy storage equipment, thereby improving the economic efficiency and environmental friendliness of power plant operation. Furthermore, this method offers fast response and high control precision, providing reliable technical support for achieving the goal of minimizing photovoltaic curtailment.

[0074] The method of utilizing deaerator heat storage to absorb curtailed photovoltaic power in this embodiment of the invention can effectively reduce the curtailment rate of photovoltaic power, improve the local absorption capacity of clean energy, and at the same time achieve low-cost heat storage regulation by utilizing existing deaerators to ensure the stable operation of the power plant's thermal system.

[0075] Furthermore, S4 includes: S41, when the deaerator heat storage volume is greater than 10%, gradually reduce the boiler load, with an adjustment rate not exceeding 3% of the rated load per minute.

[0076] Specifically, when the deaerator's heat storage volume is greater than 10%, the boiler load is gradually reduced, with an adjustment rate not exceeding 3% of the rated load per minute. This is one of the key steps in realizing the "minimal photovoltaic curtailment rate" control logic in this invention. It is mainly used to restore the boiler to normal operating load after the deaerator completes its heat release operation, while avoiding instability in the thermal system or equipment over-limit operation caused by sudden load changes.

[0077] This step involves the boiler main control system receiving a deaerator heat release stop command and initiating a closed-loop regulation mechanism to gradually adjust the boiler load from the current operating point towards the "boiler demand for evaporation." Boiler load adjustment primarily relies on the coordinated control of parameters such as combustion rate, feedwater flow rate, and main steam pressure. The adjustment rate is limited to 3% of rated load per minute, complying with the safety recommendations for load change rates in ASME PTC 4.1-2013 "Boiler Performance Testing Procedures," while also preventing a rapid decrease in turbine steam intake due to excessively rapid load reduction, which could affect the stability of the deaerator heat release process.

[0078] Boiler rated load is typically expressed as steam output per unit time (e.g., t / h) or power generation (e.g., MW). The regulation rate setting needs to consider the boiler combustion system response characteristics and the deaerator's heat storage and release capacity. For example, in a boiler system with a rated load of 400 t / h, a 3% regulation rate corresponds to a load change of 12 t / h per minute. The deaerator's heat storage volume is calculated based on the difference between its current liquid level and the rated liquid level. Combined with the deaerator's geometric volume and the specific heat capacity of water (approximately 4.186 kJ / kg·K), the current heat storage capacity can be estimated, thus determining whether the heat release termination condition has been met.

[0079] This step is applicable during periods when photovoltaic output decreases and plant power demand is reduced, such as after the midday solar peak when photovoltaic output gradually declines. At this time, the deaerator has stored enough heat, which can be gradually released to maintain heating demand. By slowly reducing the boiler load, the system can smoothly transition to normal heating mode, avoiding deaerator pressure fluctuations or liquid level runaway caused by sudden load changes, thereby ensuring the safe operation of the thermal system.

[0080] This step effectively achieves coordinated control of deaerator heat storage and boiler load regulation, ensuring that the system can quickly and smoothly recover to normal operation after a decrease in photovoltaic power. Simultaneously, by limiting the load regulation rate, it avoids thermal stress and efficiency reduction issues caused by frequent adjustments in the boiler combustion system, improving the system's operational economy and stability. As the "heat release termination" link in the entire control logic, this step is a crucial guarantee for realizing the dynamic response mechanism of "excess heat storage, deficiency heat release," demonstrating significant engineering practical value and innovation.

[0081] S42, if the target boiler load drops below 80% of the required evaporation capacity, the boiler load will be maintained at 80% of the required evaporation capacity and will not be reduced further.

[0082] Specifically, in some implementations, when the photovoltaic output continues to decline, causing the boiler load target value to drop below 80% of the required evaporation capacity, the system will automatically maintain the boiler load at 80% of the required evaporation capacity and prevent it from decreasing further. This step is a key control strategy in the "deaerator heat release process" of this invention, aiming to prevent safety hazards such as unstable combustion and decreased steam-water circulation efficiency caused by excessively low boiler load, while ensuring the controllability of the deaerator heat storage and release process and the overall stability of the system.

[0083] This step relies on the coordinated response of closed-loop control logic and the boiler main control system. When the system detects that the photovoltaic power generation is consistently lower than the required plant power consumption and triggers the deaerator heat release command, the boiler main control module dynamically adjusts the boiler evaporation rate based on the real-time calculated plant power consumption demand. During the gradual decrease in load, if the target evaporation rate is lower than 80% of the required evaporation rate (i.e., the minimum stable load of the boiler under normal heating conditions), the system will automatically lock the target load at 80% of the required evaporation rate to prevent further reduction. At this time, the boiler maintains operation at this load level, and the steam turbine intake is reduced accordingly, thereby reducing power generation output to match the decreasing trend of photovoltaic output and achieve a dynamic balance between plant power consumption and power generation.

[0084] The 80% evaporation capacity requirement is a safety threshold set based on the boiler's minimum stable combustion load. Typically, Huaneng Nanjing Thermal Power Plant's minimum stable combustion load without oil injection is 35% BMCR, which is 0.35 * 495 = 173.25 t / h. This threshold setting needs to consider comprehensive factors such as boiler combustion stability, steam-water circulation efficiency, and deaerator heat release rate.

[0085] This step is primarily applicable during periods of rapid decline in photovoltaic output, such as afternoon when sunlight weakens or during sudden weather changes. In these scenarios, without control, boiler load may drop to an unsafe range, affecting unit operating efficiency and even posing a risk of shutdown. By maintaining boiler load at 80% of required evaporation capacity, the system can maximize the utilization of the deaerator's heat storage capacity while ensuring safety, thus achieving on-site absorption of surplus photovoltaic power.

[0086] S5, when the deaerator heat storage volume is less than 2%, triggers the deaerator heat storage start-up preparation command. The boiler main controller presets the boiler load increase strategy based on the difference between the current plant power consumption and photovoltaic power generation, in order to prepare for the heat storage operation during the next round of photovoltaic over-generation.

[0087] In some implementations, the deaerator's thermal storage volume is calculated based on the ratio of its liquid level to its design volume. This is typically achieved by real-time data acquisition from a level transmitter in the DCS system, combined with the deaerator's geometric parameters (such as diameter, height, and effective thermal storage area) for volume conversion. When the thermal storage volume falls below 2%, it indicates that the deaerator has released most of its stored thermal energy and is ready for re-storage. At this point, the system sends a thermal storage start-up preparation command to the boiler main control system via a logic judgment module. The boiler main control system calculates the target boiler load based on the difference between the current plant power consumption and photovoltaic power generation, combined with a preset load boosting strategy. This strategy is typically based on the unit's thermoelectric coupling characteristics and employs PID control algorithms or fuzzy control logic to ensure the smoothness and responsiveness of the load adjustment process.

[0088] Key parameters in this step include: plant power consumption (kW), photovoltaic power generation (kW), boiler evaporation demand (t / h), deaerator thermal storage volume (%), and boiler load variability (generally controlled at ≤5% of rated load / min). In addition, the system needs to set a trigger threshold (2%) for thermal storage startup preparation, and a comparison coefficient between plant power consumption and photovoltaic power generation (e.g., 105%) to ensure timely startup of the thermal storage process in the event of photovoltaic over-generation.

[0089] This step is applicable to scenarios where photovoltaic output fluctuates significantly and the power plant is operating at low load, such as during midday on a sunny day when photovoltaic output exceeds the plant's power demand, causing the grid to be unable to absorb the power in time. In this case, the system prepares for boiler load increases in advance, creating conditions for excess steam from the turbine to enter the deaerator for heat storage, thereby avoiding the waste of clean energy caused by inverter shutdown.

[0090] This step, through advance prediction and preparation, effectively shortens the system's response time from photovoltaic over-generation to deaerator heat storage startup, enhancing the dynamic adaptability of the overall control system. Simultaneously, by adjusting the boiler load in a closed-loop manner, it ensures a dynamic balance between plant power consumption and photovoltaic power generation, thereby minimizing the photovoltaic curtailment rate.

[0091] S6, the preset boiler load increase strategy includes predicting future changes in plant power demand based on historical photovoltaic output curves. After predicting that photovoltaic power will be over-generated, the boiler load is increased in advance to make the load exceed the required evaporation, so that the plant power consumption of the unit increases to 105% of the photovoltaic power generation.

[0092] Specifically, in some implementations, the preset boiler load increase strategy predicts future changes in plant power demand based on historical photovoltaic output curves. Based on this prediction, after anticipating potential over-generation of photovoltaic power, the boiler load is increased in advance to exceed the required evaporation capacity, thereby increasing the unit's power consumption to 105% of photovoltaic power generation. This achieves efficient local consumption of curtailed photovoltaic power. The core of this strategy lies in combining a data-driven predictive model with closed-loop control logic to improve the system's foresight and stability.

[0093] This step first collects and analyzes historical photovoltaic (PV) power output data, combining it with parameters such as weather forecasts and solar irradiance trends to construct a PV power output prediction model. This model can use time series analysis (such as ARIMA or LSTM neural networks) or physics-based PV power prediction methods to predict the PV power output curve for the next 1-3 hours. Subsequently, the system compares the prediction results with the current plant power load to calculate the potential future PV over-generation. When the predicted plant power demand is less than 105% of the PV power generation, the system enters the over-generation warning stage and triggers a boiler load increase command.

[0094] The target value for boiler load adjustment is determined by the ratio of plant power consumption to photovoltaic power generation. Specifically, when plant power consumption equals 105% of photovoltaic power generation, the system calculates the corresponding boiler evaporation rate using a fitting formula, which serves as the target boiler load. Based on this target value, the boiler main control system adjusts parameters such as combustion rate, air supply, and water supply to gradually increase the boiler load, ensuring dynamic matching between plant power consumption and photovoltaic output.

[0095] At the application level, this strategy is suitable for back-pressure turbine units that operate on a heat-driven power generation model, where the heating network and deaerator steam inlet are connected. By adjusting the boiler load in advance, inverter shutdowns caused by excessive photovoltaic power generation can be effectively avoided, thus improving the utilization rate of clean energy. Simultaneously, this strategy provides the foundation for coordinated operation of deaerator-heating network steam load transfer and photovoltaic power consumption.

[0096] Furthermore, the technical benefits of this step are reflected in improved system response speed and absorption efficiency. By predicting and adjusting the load 10 minutes in advance, the boiler load variation rate can be controlled within the range of 3-5% of rated load / min, meeting the stability requirements for load regulation in the "Operating Regulations for Boilers in Thermal Power Plants" (DL / T 1055-2007). Meanwhile, referring to the actual application results of Huaneng Nanjing Thermal Power in 2024, this strategy reduced the annual photovoltaic curtailment of Huaneng Nanjing Thermal Power by 54%, significantly improving the power plant's economic and environmental benefits.

[0097] Example 2 This invention utilizes a deaerator for heat storage to absorb curtailed photovoltaic (PV) power. It addresses the problem of power curtailment caused by excessive PV generation during low-load periods in power plants, avoiding the waste of clean energy due to inverter shutdowns; reduces the cost of PV absorption by utilizing existing deaerators for heat storage without requiring additional energy storage equipment; ensures system safety by preventing grid impact from PV power grid connection, while maintaining the stability of the unit's thermal system through closed-loop regulation; and enhances the flexibility of PV absorption by achieving a dynamic response of "storing heat when there is excess and releasing heat when there is insufficient power," matching the periodic fluctuations in PV output. This invention utilizes the heat storage capacity of existing power plant deaerators, combined with dynamic control logic, to achieve on-site absorption of curtailed PV power. The specific steps are as follows: As a feedwater heating and deaeration unit in power plants, the deaerator, due to its certain heat storage capacity, can also be used as an energy storage unit to absorb some of the curtailed photovoltaic power. The specific method is as follows: When photovoltaic power generation cannot be fully absorbed by the plant's power consumption, the boiler load is increased, leading to increased equipment power consumption, increased plant power consumption, increased boiler outlet evaporation, increased steam intake to the turbine, increased power generation from the turbine generator set, and a corresponding increase in turbine exhaust steam. Assuming the heat user's steam consumption remains relatively constant, the excess turbine exhaust steam can enter the deaerator, mixing with the deaerator makeup water to complete the deaerator's water replenishment, deoxygenation, and heating processes. This process typically lasts 1-3 hours. As sunlight weakens, the excess photovoltaic power generation gradually decreases until it disappears, and the boiler load is simultaneously reduced to maintain plant power consumption slightly exceeding photovoltaic power generation until the deaerator's heat storage is complete and the boiler returns to its normal heating load. During the process of releasing stored heat from the deaerator to the heating network, the boiler load needs to be reduced, thus decreasing the steam intake to the turbine and reducing the power generation from the turbine generator set, offsetting the increased power generation during the deaerator heat storage phase.

[0098] Under the goal of "minimizing photovoltaic curtailment rate", the core of the control logic is to dynamically adjust the heat storage / release state of the deaerator by monitoring the difference between photovoltaic output and plant load in real time, so as to ensure that photovoltaic power is consumed locally as much as possible.

[0099] The core logic of this invention is to establish a real-time response mechanism of "excess heat storage and insufficient heat release." It coordinates and dynamically adjusts the boiler load and the steam and water flow rates of the deaerator to ensure that photovoltaic power is consumed locally as much as possible. First, the boiler's required evaporation capacity is defined as the steam consumption of the source heat user at 1.6 MPa (i.e., the unit's low-pressure heat supply). The boiler evaporation capacity, calculated in real-time using a formula fitting the main steam flow rate and the low-pressure heat supply, corresponds to the plant's required power consumption. The following example from the Huaneng Nanjing Thermal Power Plant illustrates the control logic design: In one embodiment of the present invention, the deaerator thermal storage-photovoltaic absorption process, as follows: Figure 3 As shown: S201 monitors photovoltaic power generation and busbar plant power consumption in real time; S202, when the power consumption of the busbar plant is less than 105% of the photovoltaic power generation, the photovoltaic over-generation warning stage is entered; S203 incorporates a "10-minute delay" mechanism: when the busbar plant's power consumption is detected to be less than 105% of the photovoltaic power generation, heat storage is not immediately initiated. Instead, it waits for 10 minutes. If the power consumption is still less than the threshold and the photovoltaic power generation shows an upward trend, the deaerator heat storage command is triggered. S204. Based on the fact that the plant's electricity consumption equals "105% of the photovoltaic power generation", the corresponding boiler evaporation rate is calculated, which is the target load of the boiler. S205, the boiler main controller receives the deaerator heat storage command, automatically increases the boiler load to the target value, and uses the real-time detected plant power consumption to correct the target load, so that the plant power consumption is equal to "105% of photovoltaic power generation"; S206, the deaerator inlet steam regulating valve receives the deaerator heat storage command and switches the automatic control logic of the deaerator inlet steam regulating valve from "automatic tracking of deaerator pressure" to "automatic tracking of turbine exhaust pressure"; S207, the deaerator inlet water regulating valve receives the deaerator heat storage command and switches the automatic control logic of the deaerator inlet water regulating valve and deaerator inlet steam regulating valve from "automatic tracking of deaerator liquid level" to "automatic tracking of deaerator pressure". S208: As the boiler load increases, the deaerator pressure remains stable while the liquid level also rises.

[0100] In one embodiment of the present invention, the deaerator heat storage termination process triggered by reaching the upper limit of heat storage is as follows: Figure 4 As shown: S301, calculates the deaerator heat storage volume in real time based on the deaerator liquid level; S302, when the heat storage volume reaches 90%, the deaerator heat storage stop command is triggered; S303: When the boiler main controller receives the deaerator heat storage stop command, it automatically reduces the boiler load to the boiler's required evaporation capacity. S304, the deaerator inlet steam regulating valve receives the deaerator heat storage stop command. After the boiler load drops to the required evaporation rate, the automatic control logic of the deaerator inlet steam regulating valve is switched from "automatically tracking the turbine exhaust pressure" to "automatically tracking the deaerator pressure". S305, the deaerator inlet water regulating valve receives the deaerator heat storage stop command. After the boiler load drops to the required evaporation rate, the automatic control logic of the deaerator inlet water regulating valve is switched from "automatic tracking of deaerator pressure" to "automatic tracking of deaerator liquid level". S306, if the heat storage volume reaches 98%, the deaerator heat storage forced stop command is triggered; S307: When the heat storage volume rises to 90%, the boiler main control automatically reduces the boiler load target value to the boiler's required evaporation capacity. S308, the deaerator inlet steam regulating valve receives a forced stop command for deaerator heat storage and switches the automatic control logic of the deaerator inlet steam regulating valve from "automatic tracking of turbine exhaust pressure" to "automatic tracking of deaerator pressure"; S309, the deaerator inlet water regulating valve receives a forced stop command for deaerator heat storage and switches the automatic control logic of the deaerator inlet water regulating valve from "automatic tracking of deaerator pressure" to "automatic tracking of deaerator liquid level".

[0101] In one embodiment of the present invention, the deaerator heat storage shutdown process triggered by a decrease in photovoltaic power is as follows:Figure 5 As shown: S401, as sunlight weakens and photovoltaic power decreases, it monitors and compares photovoltaic power generation with the demand for plant power consumption in real time. S402: When the photovoltaic power generation is detected to be lower than 103% of the required plant power consumption, wait for 10 minutes. If it is still detected to be lower than the threshold and the photovoltaic power generation is showing a downward trend, trigger the deaerator heat storage stop command. S403, the boiler main control receives the deaerator heat storage stop command and sets the boiler target load to the boiler's required evaporation rate; S404, the deaerator inlet steam regulating valve receives the deaerator heat storage stop command. After the boiler load drops to the required evaporation rate, the automatic control logic of the deaerator inlet steam regulating valve is switched from "automatic tracking of turbine exhaust pressure" to "automatic tracking of deaerator pressure". S405, the deaerator inlet water regulating valve receives the deaerator heat storage stop command. After the boiler load drops to the required evaporation rate, the automatic control logic of the deaerator inlet water regulating valve is switched from "automatic tracking of deaerator pressure" to "automatic tracking of deaerator liquid level". S406, when the photovoltaic power generation is detected to be less than or equal to the required plant power consumption, a forced shutdown command for the deaerator heat storage is triggered. S407, the boiler main control receives a forced shutdown command for deaerator heat storage and automatically reduces the boiler load to the boiler's required evaporation capacity. S408, the deaerator inlet steam regulating valve receives a forced stop command for deaerator heat storage and switches the automatic control logic of the deaerator inlet steam regulating valve from "automatic tracking of turbine exhaust pressure" to "automatic tracking of deaerator pressure"; S409, the deaerator inlet water regulating valve receives a forced stop command for deaerator heat storage and switches the automatic control logic of the deaerator inlet water regulating valve from "automatic tracking of deaerator pressure" to "automatic tracking of deaerator liquid level".

[0102] In one embodiment of the present invention, the deaerator heat release process, such as... Figure 6 As shown: S501 After the deaerator heat storage stops and the photovoltaic power generation continues to decrease to below the required plant power consumption, when the current plant power consumption is detected to be greater than 110% of the photovoltaic power generation and the difference is still greater than the threshold after a 10-minute delay, the deaerator heat release command is triggered. S502, the boiler main controller receives the deaerator heat release command and reduces the boiler load to the boiler evaporation rate corresponding to "105% of photovoltaic power generation" in plant power consumption, which is the boiler target load; S503 As photovoltaic power generation continues to decline, the target value of boiler load also decreases. In order to avoid a significant reduction in boiler load, when the target value drops to 80% of the required evaporation, the main control target load of the boiler will be adjusted to 80% of the required evaporation. S504, the deaerator inlet steam regulating valve receives a deaerator heat release command and switches the automatic control logic of the deaerator inlet steam regulating valve from "automatic tracking of deaerator pressure" to "automatic tracking of turbine exhaust pressure". S505, the deaerator inlet water regulating valve receives the deaerator heat release command and switches the automatic control logic of the deaerator inlet water regulating valve from "automatic tracking of deaerator liquid level" to "automatic tracking of deaerator pressure". S506, as the boiler load decreases, the deaerator pressure remains stable while the liquid level also decreases.

[0103] In one embodiment of the present invention, the deaerator heat release termination process, such as... Figure 7 As shown: S601 calculates the current heat storage volume of the deaerator in real time based on the deaerator liquid level. S602, after the deaerator reaches 10% of its heat storage capacity, a deaerator heat release stop command is triggered. S603, the boiler main control receives the deaerator heat release stop command and gradually increases the boiler load to the target value, which is the boiler's required evaporation rate; S604, when the deaerator inlet steam regulating valve receives the deaerator heat release stop command, after the boiler load rises to the required evaporation rate, the automatic control logic of the deaerator inlet steam regulating valve is switched from "automatic tracking of turbine exhaust pressure" to "automatic tracking of deaerator pressure". S605, the deaerator inlet water regulating valve receives a deaerator heat release stop command. After the boiler load rises to the required evaporation rate, the automatic control logic of the deaerator inlet water regulating valve is switched from "automatic tracking of deaerator pressure" to "automatic tracking of deaerator liquid level". S606, after the deaerator reaches 2% of its heat storage volume, a forced stop command for deaerator heat release is triggered. S607, the deaerator inlet steam regulating valve receives a forced stop command for deaerator heat release and switches the automatic control logic of the deaerator inlet steam regulating valve from "automatic tracking of turbine exhaust pressure" to "automatic tracking of deaerator pressure"; S608, the deaerator inlet water regulating valve receives a forced stop command for deaerator heat release and switches the automatic control logic of the deaerator inlet water regulating valve from "automatic tracking of deaerator pressure" to "automatic tracking of deaerator liquid level".

[0104] In summary, the beneficial effects of the present invention are as follows: Extremely low cost: By retrofitting existing deaerators, the total retrofit cost is only 1 / 10 of that of chemical battery energy storage, and the total life cycle cost is 1 / 17 of that of chemical battery solutions. High compatibility: Seamlessly connects with power plant thermal systems, avoiding the impact of photovoltaic grid connection on the power grid and ensuring stable operation of the unit; High efficiency in grid integration: Based on the actual application effect of Huaneng Nanjing Thermal Power in 2024, this strategy reduced the annual photovoltaic curtailment of Huaneng Nanjing Thermal Power by 54%; High flexibility: Through a 10-minute delay mechanism and dynamic adjustment, it adapts to the intermittent fluctuations of photovoltaic power, balancing absorption efficiency and system safety.

[0105] Example 3 To achieve the above embodiments, such as Figure 8 As shown, this embodiment also provides a device 10 for utilizing deaerator heat storage to absorb abandoned photovoltaic power, including: The photovoltaic power generation and plant power consumption monitoring module 100 is used to monitor the photovoltaic power generation and plant power consumption in real time and calculate the difference between the two. The deaerator heat storage triggering and load regulation module 200 is used to trigger the deaerator heat storage command when the plant power consumption is less than 105% of the photovoltaic power generation for more than 10 minutes. The module adjusts the boiler load to make the plant power consumption equal to 105% of the photovoltaic power generation, and at the same time introduces the excess turbine exhaust steam into the deaerator for heat storage. The thermal storage volume calculation and shutdown control module 300 is used to calculate the thermal storage volume in real time based on the deaerator liquid level. When the thermal storage volume reaches the preset upper limit, it triggers the deaerator thermal storage shutdown command. When the photovoltaic power decreases, it triggers the thermal storage shutdown command, restores the boiler load to the required evaporation rate, and switches the control mode of the deaerator steam inlet regulating valve and water inlet regulating valve to maintain system stability. The deaerator heat release trigger and load reduction module 400 is used to trigger the deaerator heat release command when the photovoltaic power generation continuously decreases to below the required plant power consumption. When the actual plant power consumption is greater than 110% of the photovoltaic power generation, the boiler load is reduced to reduce the plant power consumption to 105% of the photovoltaic power generation, so as to utilize the deaerator to release stored heat to balance the system energy demand.

[0106] Furthermore, the photovoltaic power generation and plant power monitoring module is also used for: Real-time power data is collected by smart meters installed at the photovoltaic grid connection point and the plant power bus, with a sampling frequency of 1 minute; The collected power data is filtered using a moving average algorithm to eliminate the influence of instantaneous fluctuations on the judgment threshold.

[0107] Furthermore, the deaerator heat storage triggering and load regulation module is also used for: Based on the photovoltaic power output prediction model, it is determined whether the photovoltaic power generation will continue to rise in the next 10 minutes. If it does, the system will enter the heat storage preparation state in advance. The boiler load regulation adopts a PID control algorithm, and the regulation rate is set to not exceed 5% of the rated load / minute to ensure the boiler combustion stability.

[0108] Furthermore, the heat storage volume calculation and shutdown control module is also used for: The preset upper limit includes two levels: triggering a heat storage stop command when the heat storage volume reaches 90%, and triggering a forced heat storage stop command when it reaches 98%. The control mode switching between the deaerator steam inlet regulating valve and the deaerator water inlet regulating valve adopts an interlocking mechanism to ensure that the regulating valve mode switching is not only performed after the boiler load adjustment is completed.

[0109] Furthermore, the deaerator heat release triggering and load reduction module is also used for: When the deaerator's heat storage capacity is greater than 10%, gradually reduce the boiler load, with an adjustment rate not exceeding 3% of the rated load per minute; If the boiler load target value drops below 80% of the required evaporation capacity, the boiler load will be maintained at 80% of the required evaporation capacity and will not be reduced further.

[0110] Furthermore, it also includes: The thermal storage start-up preparation module is used to trigger the deaerator thermal storage start-up preparation command when the deaerator thermal storage volume is less than 2%. The boiler main controller presets the boiler load increase strategy based on the difference between the current plant power consumption and photovoltaic power generation, in order to prepare for the thermal storage operation during the next round of photovoltaic over-generation. The load strategy prediction module is used for the preset boiler load increase strategy, which includes predicting future changes in plant power demand based on historical photovoltaic output curves. After predicting that photovoltaic power will be over-generated, the boiler load is increased in advance to make the load exceed the required evaporation, thereby increasing the plant power consumption of the unit to 105% of the photovoltaic power generation.

[0111] The device for utilizing deaerator heat storage to absorb curtailed photovoltaic power in this invention can effectively reduce the curtailment rate of photovoltaic power, improve the local absorption capacity of clean energy, and at the same time achieve low-cost heat storage regulation by utilizing existing deaerators to ensure the stable operation of the power plant's thermal system.

[0112] In the description of this specification, the references to "one embodiment," "some embodiments," "example," "specific example," or "some examples" refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0113] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two or three, unless otherwise explicitly specified.

Claims

1. A method for utilizing deaerator heat storage to absorb and utilize waste photovoltaic power, characterized in that, include: S1 monitors photovoltaic power generation and plant power consumption in real time and calculates the difference between the two; S2, when the plant power consumption is less than 105% of the photovoltaic power generation and lasts for more than 10 minutes, the deaerator heat storage command is triggered. The boiler load is adjusted to make the plant power consumption equal to 105% of the photovoltaic power generation, and the excess steam from the turbine is introduced into the deaerator for heat storage. S3 calculates the heat storage volume in real time based on the deaerator liquid level. When the heat storage volume reaches the preset upper limit, a deaerator heat storage stop command is triggered. When the photovoltaic power decreases, a heat storage stop command is triggered to restore the boiler load to the required evaporation rate and switch the control modes of the deaerator steam inlet regulating valve and water inlet regulating valve to maintain system stability. S4. When the photovoltaic power generation continues to drop below the required plant power consumption, the deaerator heat release command is triggered. When the actual plant power consumption is greater than 110% of the photovoltaic power generation, the boiler load is reduced to reduce the plant power consumption to 105% of the photovoltaic power generation, so as to use the deaerator to release stored heat to balance the system energy demand.

2. The method as described in claim 1, characterized in that, S1 includes: S11 collects real-time power data through smart meters installed at the photovoltaic grid connection point and the plant power bus, with a sampling frequency of 1 minute; S12 uses a moving average algorithm to filter the collected power data, eliminating the influence of instantaneous fluctuations on the judgment threshold.

3. The method as described in claim 1, characterized in that, S2 includes: S21. Based on the photovoltaic output prediction model, determine whether the photovoltaic power generation will continue to rise in the next 10 minutes. If it does, enter the heat storage preparation state in advance. S22, the boiler load regulation adopts a PID control algorithm, and the regulation rate is set to not exceed 5% of the rated load / minute to ensure the boiler combustion stability.

4. The method as described in claim 1, characterized in that, S3 includes: S31, the preset upper limit includes two levels: triggering a heat storage stop command when the heat storage volume reaches 90%, and triggering a heat storage forced stop command when it reaches 98%. S32, the control mode switching of the deaerator steam inlet regulating valve and water inlet regulating valve adopts an interlocking mechanism to ensure that the regulating valve mode switching is not only performed after the boiler load adjustment is completed.

5. The method as described in claim 1, characterized in that, S4 includes: S41, when the deaerator heat storage volume is greater than 10%, gradually reduce the boiler load, and the adjustment rate shall not exceed 3% of the rated load / minute; S42, if the target boiler load drops below 80% of the required evaporation capacity, the boiler load will be maintained at 80% of the required evaporation capacity and will not be reduced further.

6. The method as described in claim 1, characterized in that, Also includes: S5, when the deaerator heat storage volume is less than 2%, trigger the deaerator heat storage start-up preparation command. The boiler main controller presets the boiler load increase strategy based on the difference between the current plant power consumption and photovoltaic power generation, in order to prepare for the heat storage operation during the next round of photovoltaic over-generation. S6, the preset boiler load increase strategy includes predicting future changes in plant power demand based on historical photovoltaic output curves. After predicting that photovoltaic power will be over-generated, the boiler load is increased in advance to make the load exceed the required evaporation, thereby increasing the plant power consumption of the unit to 105% of the photovoltaic power generation.

7. A device for utilizing deaerator heat storage to absorb waste photovoltaic power, characterized in that, include: The photovoltaic power generation and plant power consumption monitoring module is used to monitor the photovoltaic power generation and plant power consumption in real time and calculate the difference between the two. The deaerator heat storage triggering and load regulation module is used to trigger the deaerator heat storage command when the plant power consumption is less than 105% of the photovoltaic power generation for more than 10 minutes. The module adjusts the boiler load to make the plant power consumption equal to 105% of the photovoltaic power generation, and at the same time introduces the excess turbine exhaust steam into the deaerator for heat storage. The heat storage volume calculation and shutdown control module is used to calculate the heat storage volume in real time based on the deaerator liquid level. When the heat storage volume reaches the preset upper limit, it triggers the deaerator heat storage shutdown command, restores the boiler load to the required evaporation rate, and switches the control mode of the deaerator steam inlet valve and water inlet valve to maintain system stability. The deaerator heat release trigger and load reduction module is used to trigger a deaerator heat release command when the photovoltaic power generation continuously decreases to below the required plant power consumption, and to trigger a heat storage stop command when the photovoltaic power generation decreases. When the actual plant power consumption is greater than 110% of the photovoltaic power generation, the boiler load is reduced to reduce the plant power consumption to 105% of the photovoltaic power generation, so as to utilize the deaerator to release stored heat to balance the system energy demand.

8. The apparatus as claimed in claim 7, characterized in that, The photovoltaic power generation and plant power monitoring module is also used for: Real-time power data is collected by smart meters installed at the photovoltaic grid connection point and the plant power bus, with a sampling frequency of 1 minute; The collected power data is filtered using a moving average algorithm to eliminate the influence of instantaneous fluctuations on the judgment threshold.

9. The apparatus as claimed in claim 7, characterized in that, The deaerator heat storage triggering and load regulation module is also used for: Based on the photovoltaic power output prediction model, it is determined whether the photovoltaic power generation will continue to rise in the next 10 minutes. If it does, the system will enter the heat storage preparation state in advance. The boiler load regulation adopts a PID control algorithm, and the regulation rate is set to not exceed 5% of the rated load / minute to ensure the boiler combustion stability.

10. The apparatus as claimed in claim 7, characterized in that, The thermal storage volume calculation and termination control module is also used for: The preset upper limit includes two levels: triggering a heat storage stop command when the heat storage volume reaches 90%, and triggering a forced heat storage stop command when it reaches 98%. The control mode switching between the deaerator steam inlet regulating valve and the deaerator water inlet regulating valve adopts an interlocking mechanism to ensure that the regulating valve mode switching is not only performed after the boiler load adjustment is completed.

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