Energy management system for sewage treatment plant

Abstract

The invention discloses an energy management system for a sewage treatment plant. The energy management system comprises an energy storage subsystem, an electricity utilization subsystem, a data acquisition layer and an energy management system, the energy storage subsystem is used for storing and releasing electric energy; the electronic system comprises an aeration machine, a water pump and auxiliary equipment, and the aeration machine is provided with a frequency converter; the data acquisition layer comprises a programmable logic controller, an intelligent electric meter and a dissolved oxygen sensor, and the programmable logic controller acquires data of the intelligent electric meter and the frequency converter through a communication interface and endows the acquired data with the system clock time of the programmable logic controller as a unified timestamp; and the energy management system is used for receiving data with a unified timestamp transmitted by the programmable logic controller through an OPC protocol, predicting the power demand of the aerator based on the dissolved oxygen deviation, and executing a cooperative control strategy of aerator priority peak clipping and energy storage subsystem compensation.

Description

Technical Field

[0001] This invention relates to the field of power supply and distribution and energy storage system integration, specifically to an energy management system for wastewater treatment plants. Background Technology

[0002] With the increasing demand for intelligent power control and the growing application of renewable energy, energy storage systems are gradually permeating various industries. Wastewater treatment plants, as high-energy-consuming units, occupy large areas, operate for long hours, and have high equipment power consumption, especially aerators and water pumps. When these devices are running simultaneously, they create peak loads, putting significant pressure on the power grid. Furthermore, the electricity costs of wastewater treatment plants are affected by peak-valley price differences; without proper control, not only are electricity costs high, but they also face the risk of being forced to respond to power grid curtailments.

[0003] Existing technologies suffer from the following pain points: First, the problem of control silos. Current power management systems and process control data acquisition and monitoring systems are often disconnected. The power management system focuses only on power output, while the data acquisition and monitoring system focuses only on effluent quality such as dissolved oxygen. This lack of deep coupling between process and energy prevents the utilization of the regulatory potential of process equipment to participate in grid response. Second, the problem of data temporal and spatial asynchrony. In scenarios with multiple connected devices, the internal clocks of devices such as smart meters and frequency converters are inconsistent, causing time deviations in the instantaneous power collected by the power management system. This fails to accurately reflect the load superposition at the same moment, resulting in distorted load statistics and misleading control decisions. Third, the limited control methods. Existing solutions largely rely on energy storage systems for peak shaving and valley filling, neglecting the flexible load characteristics of high-power equipment such as aerators. This leads to excessively large energy storage capacity and high investment costs. Summary of the Invention

[0004] This invention provides an energy management system for wastewater treatment plants, which solves the technical problems of existing energy management systems being disconnected from process control systems, load statistics distortion caused by asynchronous data acquisition clocks of multiple devices, and over-reliance on energy storage systems for peak shaving and valley filling while neglecting the flexible adjustment capabilities of process equipment.

[0005] To solve the above-mentioned technical problems, the present invention provides an energy management system for wastewater treatment plants, characterized in that it includes: an energy storage subsystem, an electronic system, a data acquisition layer, and an energy management system; The energy storage subsystem is used to store and release electrical energy; The electronic system includes an aerator, a water pump, and auxiliary equipment, wherein the aerator is equipped with a frequency converter; The data acquisition layer includes a programmable logic controller (PLC), a smart meter, and a dissolved oxygen sensor. The PLC acquires data from the smart meter and the frequency converter through a communication interface and assigns the acquired data a unified timestamp using the PLC's system clock time. The energy management system receives data with a unified timestamp transmitted by the programmable logic controller via the OPC protocol, predicts the power demand of the aerator based on dissolved oxygen deviation, and executes a coordinated control strategy of prioritizing peak shaving by the aerator and compensation by the energy storage subsystem.

[0006] Preferably, the programmable logic controller (PLC) adopts a sampling period of 1 to 5 seconds, acquires the current system clock time at the end of each acquisition, and assigns the system clock time as a unique timestamp to the smart meter data and the inverter energy consumption register data. The energy management system uses the timestamp marked by the PLC for data alignment and calculation.

[0007] Preferably, the energy management system calculates the instantaneous power of a single aerator based on the collected three-phase line voltage, line current, and power factor, using the following formula: ; in, This indicates that the i-th aerator is in Instantaneous power at a given moment This indicates that the i-th aerator is in Real-time three-phase line voltage at any given moment. This indicates that the i-th aerator is in Real-time three-phase line current at any given moment. This indicates that the i-th aerator is in Real-time power factor at any given time.

[0008] Preferably, the energy management system sets the minimum operating power of a single aerator according to process requirements. And calculate the adjustable power range of a single aerator: ; in, This indicates that the i-th aerator is in Adjustable power range at any time This indicates that the i-th aerator is in Instantaneous power at a given moment This represents the minimum operating power of the i-th aerator; The energy management system calculates the maximum peak-shaving capacity of all aerators as the sum of the adjustable power space of each individual aerator.

[0009] Preferably, the energy management system predicts the aerator power demand based on dissolved oxygen deviation by: obtaining the current dissolved oxygen content in the wastewater treatment tank based on a dissolved oxygen sensor. According to the dissolved oxygen standard value Calculate the dissolved oxygen difference: ; in, This represents the difference in dissolved oxygen at time t. This represents the standard setpoint for dissolved oxygen at time t. This represents the measured dissolved oxygen value at time t; when A value greater than zero indicates oxygen deficiency and requires increased aeration. A value less than zero indicates sufficient dissolved oxygen, which can reduce aeration.

[0010] Preferably, the energy management system predicts the aeration power for future control cycles based on the relationship between aeration power and dissolved oxygen difference, using the following prediction formula: ; in, Indicates the future regulatory cycle Predicted total power of aerator at any given time. This is the reference power for aeration. This is the ratio of dissolved oxygen difference to aeration power. Indicating future regulatory cycles Dissolved oxygen deviation at any given time For the regulation cycle.

[0011] Preferably, the energy management system combines the predicted power of the aerator with the real-time power of other electrical equipment to obtain the predicted power load of the entire plant within the control period. And calculate the load over-limit gap based on the load limit instructions issued by the power grid: ; in, This represents the load over-limit gap calculated at time t. This indicates the plant's predicted electricity load during the control period. The maximum allowable power load limit issued by the power grid or set by the system.

[0012] Preferably, when the load exceeds the limit... When the power is greater than zero, the energy management system performs peak shaving decisions, including: if the total power that can be reduced by all aerators is greater than or equal to the load overload gap, then an instruction is issued to reduce the frequency of the aerators to reduce the total power, and the energy storage subsystem is put on standby; if the total power that can be reduced by all aerators is less than the load overload gap, then an instruction is issued to reduce the aerators to the minimum safe power, and the remaining gap is covered by the discharge of the energy storage subsystem.

[0013] Preferably, when the energy management system determines that the power grid is in a low-load period or a low-electricity-price period, and the aerator is not operating at maximum power and the dissolved oxygen has not reached the upper limit threshold, the energy management system controls the aerator to increase its operating power, thereby completing part of the aeration task ahead of schedule while meeting the constraints of the wastewater treatment process, and transferring the aeration electricity originally in the high-load period to the low-load period to achieve load filling.

[0014] Preferably, the data acquisition layer further includes a sub-circuit meter, which is installed on the aerator and water pump for real-time monitoring of the energy consumption of high-energy-consuming equipment; the smart meter reads the data from the inverter's energy consumption register through an RS485 interface and connects to the programmable logic controller (PLC); the PLC performs normalization processing on the acquired data to ensure that the power data of different devices are on the same scale.

[0015] The beneficial effects of the present invention include at least the following: This invention establishes a mechanism based on a unified time base of a programmable logic controller (PLC), which eliminates the original time of various terminal devices such as electricity meters and frequency converters. Instead, the PLC uniformly assigns a timestamp during sampling, solving the problem of distortion of instantaneous load values ​​caused by asynchronous sampling of multiple devices and ensuring the accuracy of load calculation in the energy management system.

[0016] This invention utilizes dissolved oxygen deviation to predict aeration power demand in future cycles, and establishes a cross-domain coupling model of process control variables, energy management variables, and power grid regulation variables, realizing a shift from passive power consumption to active process response.

[0017] This invention establishes a collaborative control logic that prioritizes aerator load adjustment and uses energy storage system as a fallback. Without sacrificing the wastewater treatment process, it maximizes the utilization of the equipment's own adjustment capabilities, significantly reduces the number of charge-discharge cycles and the configuration capacity of the energy storage system, and ensures the safety of effluent water quality through minimum power constraints. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the method flow according to an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0020] like Figure 1As shown in the figure, this embodiment of the invention provides an energy management system for wastewater treatment plants, comprising four core components: an energy storage subsystem, an electronic system, a data acquisition layer, and an energy management system.

[0021] The energy storage subsystem, as a key component of the energy side, undertakes the functions of storing and releasing electrical energy, and plays a supplementary role in peak shaving and valley filling during load regulation. Electronic systems constitute the main electrical load of the wastewater treatment plant, encompassing aerators, pumps, and various auxiliary equipment. Aerators, as high-energy-consuming equipment, are equipped with frequency converters, enabling continuous power regulation. The data acquisition layer, composed of programmable logic controllers, smart meters, and dissolved oxygen sensors, is responsible for collecting operational data from all equipment in the plant and uniformly timestamping it. The energy management system, as the control core of the entire system, receives and processes the data transmitted from the acquisition layer, and executes load forecasting and coordinated control strategies.

[0022] Wastewater treatment plants can be divided into pretreatment stations, biological treatment stations, sedimentation tanks and sludge treatment units, and conveying and auxiliary units according to the process sequence. The pretreatment station is equipped with bar screens, lift pumps, sand separators, and auxiliary devices such as air intake and exhaust equipment, refrigeration equipment, and water supply equipment. The biological treatment station is the most energy-intensive area, with main equipment including aerators, chemical feed pumps, water pumps, mixers, propellers, and various metering sensors. The sedimentation tanks and sludge treatment unit are equipped with scrapers, thickeners, centrifugal dewatering machines, belt filter presses, and conveyors. The conveying and auxiliary units include lift pumps, water valves, electrical control cabinets, and air compressors. These devices together constitute the complex electrical load system of a wastewater treatment plant, with the operating status of high-energy-consuming equipment such as aerators and water pumps having a decisive impact on the overall energy consumption level of the plant.

[0023] The data acquisition layer employs a layered architecture to achieve accurate monitoring of equipment energy consumption. For high-energy-consuming equipment such as aerators and water pumps, the system uses dedicated circuit meters for specific metering to monitor their operational energy consumption in real time. Other equipment uses smart meters for centralized metering, with auxiliary verification via the inverter's energy consumption register. The smart meters read data from the inverter's energy consumption register via an RS485 communication interface and transmit the results to the programmable logic controller (PLC). The PLC collects real-time voltage and current signals from each device and transmits the data to the energy management system via the OPC protocol. The energy management system then calculates instantaneous power and statistically analyzes equipment energy consumption based on the collected voltage and current data.

[0024] To address the data timing discrepancy issue caused by asynchronous sampling from multiple devices, this invention innovatively proposes a unified timestamp mechanism based on a programmable logic controller (PLC). The PLC samples at 1-5 second intervals, reading electricity consumption data from smart meters and energy consumption registers from frequency converters via communication interfaces. Upon completion of each sampling, the PLC acquires the current system clock time and assigns it as a unique timestamp to both the smart meter data and the frequency converter energy consumption register data. This mechanism discards the original time information from each terminal device; even if there are differences in the internal update times of the meters, the system does not retain their original timestamps. Simultaneously, the PLC normalizes the collected data, ensuring that power data from different devices are compared and calculated on the same scale. The energy management system uses only the timestamp tagged by the PLC for data alignment and calculation, fundamentally eliminating errors caused by clock asynchrony at the device ends, thus preventing timing misalignment issues when calculating the total plant load.

[0025] In this embodiment of the invention, the aerator is defined as a continuously operating load that contributes the most to load regulation and can participate in load regulation within the allowable range of the process. The energy management system calculates the instantaneous power of a single aerator based on real-time data transmitted by the programmable logic controller via the OPC interface, including three-phase line voltage, line current, and power factor. For the i-th aerator, its instantaneous power calculation formula is: ; In the formula, This indicates that the i-th aerator is in Instantaneous power at a given moment This indicates that the i-th aerator is in Real-time three-phase line voltage at any given moment. This indicates that the i-th aerator is in Real-time three-phase line current at any given moment. This indicates that the i-th aerator is in Real-time power factor at time 10:00 This represents the sampling timestamp uniformly assigned by the PLC system.

[0026] The energy management system sets the lower limit of the adjustable power for a single aerator to participate in regulation, i.e., the minimum operable power, based on process requirements. .

[0027] ; In the formula, This represents the minimum operable power of the i-th aerator that meets the process requirements. This represents the rated line voltage of the i-th aerator. This represents the minimum operating current of the i-th aerator at the minimum operating frequency. This represents the rated power factor of the i-th aerator.

[0028] The setting of this minimum power value needs to comprehensively consider the basic requirements of the wastewater treatment process for dissolved oxygen concentration, ensuring that the effluent quality is not affected by excessively low aeration during the adjustment process. Based on the difference between the current operating power and the minimum operable power, the adjustable power range of a single aerator can be defined: ; In the formula, This indicates that the i-th aerator is in Maximum adjustable power range at any given time This indicates that the i-th aerator is in Instantaneous power at a given moment This represents the minimum operating power of the i-th aerator that meets the process requirements.

[0029] By summing the adjustable power ranges of all operating aerators in the plant, the maximum peak-shaving capacity of the aerator system under current operating conditions can be obtained. This indicator is a key input for the energy management system to determine whether the energy storage system needs to be activated for compensation, and directly determines the execution path of the coordinated control strategy. The current total load of all aerators can be expressed as the sum of the instantaneous power of each individual aerator, while the maximum peak-shaving capacity of all aerators is the sum of the adjustable power ranges of each individual aerator. ; In the formula, This indicates the operating status of all aerators in the entire plant. Total maximum peak shaving capacity at any given time This indicates the total number of aerators participating in the regulation. This indicates that the i-th aerator is in Instantaneous power at a given moment This represents the minimum operating power of the i-th aerator that meets the process requirements.

[0030] The energy management system uses dissolved oxygen sensors to obtain real-time dissolved oxygen levels in the wastewater treatment tank. And according to the dissolved oxygen standard value set in the process. Calculate the dissolved oxygen difference: In the formula, This represents the dissolved oxygen value at time t. This represents the dissolved oxygen calibration value at time t. The measured dissolved oxygen at time t represents the actual dissolved oxygen.

[0031] The sign of the dissolved oxygen difference directly reflects the direction of the current aeration demand. When A value greater than zero indicates that the current wastewater treatment tank is in an anoxic state, requiring increased aeration to raise the dissolved oxygen concentration; at this time, the power of the aerator will increase. When the dissolved oxygen level is less than zero, it indicates that the dissolved oxygen is sufficient or even excessive. The aeration rate can be appropriately reduced to save energy. At this time, the power of the aerator can be adjusted down.

[0032] Based on the linear relationship between aeration power and dissolved oxygen difference, the energy management system establishes a predictive model to predict the aeration power demand for a future control cycle: ; In the formula, Indicating future regulatory cycles Predicted total power of aerator at any given time. This is the reference power for aeration under current operating conditions. The response coefficient between dissolved oxygen deviation and aeration power. Indicating future regulatory cycles Dissolved oxygen deviation at any given time For the regulation cycle.

[0033] This predictive model organically links process control variables with energy management variables, realizing a shift from passive response to proactive prediction.

[0034] After obtaining the predicted power of the aerators, the energy management system combines it with the real-time power of other electrical equipment to obtain the predicted power load for the entire plant during the control period. Based on this, the energy management system works in conjunction with the power grid to calculate the load over-limit gap according to the load limitation instructions issued by the power grid: ; In the formula, This represents the load over-limit gap calculated at time t. This indicates the plant's predicted electricity load during the control period. The maximum allowable electricity load limit issued by the power grid or set by the system. Load over-limit deficit. The sign of the value determines the direction of system regulation: when the value is greater than zero, it indicates that the predicted load will exceed the grid limit and peak shaving decisions need to be implemented; when the value is less than or equal to zero, it indicates that the load is within the allowable range and the valley filling strategy can be implemented according to the electricity price period.

[0035] The energy management system integrates information from all equipment in the plant, especially the operating status of aerators and energy storage systems, and implements a hierarchical and coordinated control strategy. The core concept of this strategy is to fully explore the adjustment potential of flexible loads such as aerators, and use energy storage systems as a backup measure, thereby reducing the frequency of use and the required capacity of energy storage systems.

[0036] When the load exceeds the limit When the load is greater than zero or there is a risk of predicted overload, the energy management system enters the peak shaving decision-making process. The system first obtains the current state of charge and available discharge power of the energy storage devices. Then, based on the deviation between the dissolved oxygen setpoint and the measured value, it predicts the operating power of the aerator system in the future control cycle and calculates the range of power that can be reduced by the aerators in that control cycle by combining the predicted power with the current operating power. Based on this, the system compares the total power that can be reduced by the aerators with the load overload gap and performs tiered control: if the total power that can be reduced by all aerators is greater than or equal to the load overload gap, the total power is reduced only by decreasing the operating frequency of the aerators, while the energy storage subsystem remains in standby mode, achieving zero-cost peak shaving; if the total power that can be reduced by the aerators is less than the load overload gap, an instruction is issued to reduce the aerators to the minimum safe power, and the remaining gap is covered by the discharge of the energy storage subsystem.

[0037] When the energy management system determines that the power grid is in a low-load or low-electricity-price period, the system enters the valley-filling decision-making process. At this time, if the aerators are not operating at maximum power and dissolved oxygen has not reached the upper limit threshold, the energy management system will control the aerators to increase their operating power, completing part of the aeration task ahead of schedule while meeting the constraints of the wastewater treatment process. This pre-aeration strategy shifts the electricity that would otherwise be consumed during high-price periods to low-price periods, achieving economical valley filling and effectively reducing the electricity costs of wastewater treatment plants.

[0038] The specific implementation process of this invention can be summarized as follows: Step 1: Data cleaning based on a unified time base. The programmable logic controller (PLC) performs periodic sampling, reading data from all smart meters and frequency converters in the plant. After reading the data, the PLC immediately adds a current system timestamp, encapsulates the data packet, and uploads it to the energy management system. All device data received by the energy management system is strictly aligned on the timeline, ensuring no timing misalignment errors when calculating the total plant load.

[0039] Step Two: Plant-wide Load Forecasting and Gap Calculation. The energy management system obtains the current state of charge and available discharge power of the energy storage devices. Based on the deviation between the dissolved oxygen setpoint and the measured value, it predicts the operating power of the aerator system during the future control cycle, obtaining the predicted power of the aerators. Combining the predicted power with the current operating power, it calculates the range of power reduction that the aerators can achieve during the control cycle. The energy management system combines the predicted power of the aerators with the real-time power of other electrical equipment to obtain the plant-wide predicted power load during the control cycle, and calculates the load over-limit gap based on the load limit instructions issued by the power grid.

[0040] Step 3: Obtain the adjustable power of the aerator system. The energy management system obtains the current dissolved oxygen level and the operating status information of the aerator system, including the real-time operating voltage, current, and power factor of each aerator. Combined with the preset minimum safe operating power, it calculates the total maximum adjustable power of all operating aerator systems under the current operating conditions.

[0041] Step four: Implement a tiered coordinated control strategy. When the load over-limit gap is greater than zero or there is a predicted risk of load over-limit, the peak shaving process is initiated. The total power that the aerators can reduce is compared with the load over-limit gap, and corresponding control commands are executed. When the power grid is in a low-load or low-electricity-price period and the process conditions are met, the valley filling process is initiated. The aerators are controlled to increase their operating power to achieve load transfer.

[0042] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; only preferred embodiments of the present invention are illustrated. The descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. As long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0043] It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept, and these all fall within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the appended claims.

Claims

1. An energy management system for wastewater treatment plants, characterized in that, include: Energy storage subsystem, electronic system, data acquisition layer, and energy management system; The energy storage subsystem is used to store and release electrical energy; The electronic system includes an aerator, a water pump, and auxiliary equipment, wherein the aerator is equipped with a frequency converter; The data acquisition layer includes a programmable logic controller (PLC), a smart meter, and a dissolved oxygen sensor. The PLC acquires data from the smart meter and the frequency converter through a communication interface and assigns the acquired data a unified timestamp using the PLC's system clock time. The energy management system receives data with a unified timestamp transmitted by the programmable logic controller via the OPC protocol, predicts the power demand of the aerator based on dissolved oxygen deviation, and executes a coordinated control strategy of prioritizing peak shaving by the aerator and compensation by the energy storage subsystem.

2. The energy management system for wastewater treatment plants according to claim 1, characterized in that, The programmable logic controller (PLC) adopts a sampling period of 1 to 5 seconds. It acquires the current system clock time at the end of each acquisition and assigns the system clock time as a unique timestamp to the smart meter data and the inverter energy consumption register data. The energy management system uses the timestamp marked by the PLC for data alignment and calculation.

3. The energy management system for wastewater treatment plants according to claim 1, characterized in that, The energy management system calculates the instantaneous power of a single aerator based on the collected three-phase line voltage, line current, and power factor. The calculation formula is as follows: ； in, This indicates that the i-th aerator is in Instantaneous power at a given moment This indicates that the i-th aerator is in Real-time three-phase line voltage at any given moment. This indicates that the i-th aerator is in Real-time three-phase line current at any given moment. This indicates that the i-th aerator is in Real-time power factor at any given time.

4. The energy management system for wastewater treatment plants according to claim 3, characterized in that, The energy management system sets the minimum operating power of a single aerator according to process requirements. And calculate the adjustable power range of a single aerator: ； in, This indicates that the i-th aerator is in Adjustable power space at any time This indicates that the i-th aerator is in Instantaneous power at a given moment This represents the minimum operating power of the i-th aerator; The energy management system calculates the maximum peak-shaving capacity of all aerators as the sum of the adjustable power space of each individual aerator.

5. The energy management system for wastewater treatment plants according to claim 1, characterized in that, The energy management system predicts aerator power demand based on dissolved oxygen deviation, including: obtaining the current dissolved oxygen content in the wastewater treatment tank based on dissolved oxygen sensors. According to the dissolved oxygen standard value Calculate the dissolved oxygen difference: ； in, This represents the difference in dissolved oxygen at time t. This represents the standard setpoint for dissolved oxygen at time t. This represents the measured dissolved oxygen value at time t; when A value greater than zero indicates oxygen deficiency and requires increased aeration. A value less than zero indicates sufficient dissolved oxygen, which can reduce aeration.

6. The energy management system for wastewater treatment plants according to claim 5, characterized in that, The energy management system predicts the aeration power for future control cycles based on the relationship between aeration power and dissolved oxygen difference. The prediction formula is as follows: ； in, Indicating future regulatory cycles Predicted total power of aerator at any given time. This is the reference power for aeration. This is the ratio of dissolved oxygen difference to aeration power. Indicating future regulatory cycles Dissolved oxygen deviation at any given time For the regulation cycle.

7. The energy management system for wastewater treatment plants according to claim 6, characterized in that, The energy management system combines the predicted power of the aerators with the real-time power of other electrical equipment to obtain the predicted power load for the entire plant within the control period. And calculate the load over-limit gap based on the load limit instructions issued by the power grid: ； in, This represents the load over-limit gap calculated at time t. This indicates the plant's predicted electricity load during the control period. The maximum allowable power load limit issued by the power grid or set by the system.

8. The energy management system for wastewater treatment plants according to claim 7, characterized in that, When the load exceeds the limit When the power is greater than zero, the energy management system performs peak shaving decisions, including: if the total power that can be reduced by all aerators is greater than or equal to the load overload gap, then an instruction is issued to reduce the frequency of the aerators to reduce the total power, and the energy storage subsystem is put on standby; if the total power that can be reduced by all aerators is less than the load overload gap, then an instruction is issued to reduce the aerators to the minimum safe power, and the remaining gap is covered by the discharge of the energy storage subsystem.

9. The energy management system for wastewater treatment plants according to claim 1, characterized in that, When the energy management system determines that the power grid is in a low-load period or a low-electricity-price period, and the aerator is not operating at maximum power and the dissolved oxygen has not reached the upper limit threshold, the energy management system controls the aerator to increase its operating power. Under the premise of meeting the constraints of the sewage treatment process, it completes part of the aeration task ahead of schedule, and transfers the aeration electricity originally located in the high-load period to the low-load period to achieve load filling.

10. The energy management system for wastewater treatment plants according to claim 1, characterized in that, The data acquisition layer also includes sub-circuit meters, which are installed on aerators and water pumps to monitor the energy consumption of high-energy-consuming equipment in real time. The smart meters read the data from the inverter's energy consumption register via an RS485 interface and connect it to the programmable logic controller. The programmable logic controller normalizes the collected data to ensure that the power data of different devices are on the same scale.

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