Power supply method and system for low-carbon factory

Abstract

The invention provides a power supply method and system for a low-carbon factory, and relates to the technical field of energy storage planning. The method is applied to a micro-grid energy management system in a power supply system of a target factory, and the power supply system comprises new energy equipment and energy storage equipment. Wherein the energy storage equipment comprises flywheel energy storage equipment and lithium battery energy storage equipment; when the target factory is in the running state, the new energy equipment preferentially supplies power to the target factory; the method comprises the following steps: collecting frequency fluctuation and voltage fluctuation of a power supply system; when the frequency fluctuation is not within the preset frequency fluctuation range or the voltage fluctuation is not within the preset voltage fluctuation range, flywheel energy storage equipment is adopted for power supply; when the power supply system of the target factory is in a long-time power gap, lithium battery energy storage equipment is used for supplying power; wherein the long-time power gap indicates that the power supply amount of the flywheel energy storage equipment is smaller than the difference between the power supply amount of the power supply system and the load amount of the target factory. The stability of a power grid in a factory can be maintained.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage planning, and particularly to a power supply method and system for a low-carbon factory. Background Art

[0002] With the upgrading of global carbon emission reduction requirements, the low-carbon operation of factories has become an inevitable trend. The existing factory power supply system still mainly relies on the traditional power grid, depending on the power grid for power supply. Moreover, the proportion of clean energy is low and the transmission loss of new energy power is relatively high, resulting in low utilization efficiency of clean energy. In addition, at present, clean energy such as photovoltaic and wind energy has volatility, with poor matching with the factory load demand, and there is a lack of effective coordination of the volatility of the load and the intermittency of new energy.

[0003] At present, after new energy power generation is incorporated into the national power grid, it is supplied to the user side by the national power grid. However, compared with the mode of directly supplying wind and light power generation to the park or factory area, on the one hand, the power loss during transmission is relatively high, and on the other hand, due to additional fees such as grid connection fees, the electricity price enjoyed by the user side is also relatively high. Therefore, in areas where conditions are met, directly investing in the construction of new energy power plants such as wind and light around the user side and directly supplying their power to each user will bring considerable benefits to the user economically.

[0004] Although directly supplying wind and light power generation to users has the above advantages, directly supplying wind and light power generation to users is a power supply mode of an island microgrid or a quasi-island microgrid, which has a certain degree of instability. Moreover, this method cannot effectively coordinate the volatility of the factory load and the intermittency of new energy, resulting in not only a relatively high energy storage configuration cost but also insufficient stability of the internal power grid of the factory. Summary of the Invention

[0005] Embodiments of the present invention provide a power supply method and system for a low-carbon factory to solve the problem that it is difficult to achieve low-carbon and stable operation of the current factory power supply system.

[0006] In a first aspect, embodiments of the present invention provide a power supply method for a low-carbon factory. The method is applied to a microgrid energy management system in the power supply system of a target factory. The power supply system includes new energy equipment and energy storage equipment; among them, the energy storage equipment includes a flywheel energy storage device and a lithium battery energy storage device; when the target factory is in an operating state, the new energy equipment preferentially supplies power to the target factory; the method includes:

[0007] Collect the frequency fluctuation and voltage fluctuation of the power supply system;

[0008] When the frequency fluctuation is not within the preset frequency fluctuation range or the voltage fluctuation is not within the preset voltage fluctuation range, use the flywheel energy storage device to supply power;

[0009] When there is a long-term power gap in the power supply system of the target factory, a lithium battery energy storage device is used for power supply; where the long-term power gap means that the power supply of the flywheel energy storage device is less than the difference between the power supply of the power supply system and the load of the target factory.

[0010] In a possible implementation, the power supply system further includes a waste heat and pressure power generation device; when the target factory is in an operating state, the waste heat and pressure power generation device supplies power to the target factory based on the waste heat and pressure generated by the target factory;

[0011] When there is a long-term power gap in the power supply system of the target factory, using a lithium battery energy storage device for power supply includes:

[0012] When the power generation of the waste heat and pressure power generation device is less than a preset first power generation amount, the power supply system of the target factory is in a long-term power gap;

[0013] Start the lithium battery energy storage device for power supply, and after a first preset time, control the flywheel energy storage device to withdraw from power supply.

[0014] In a possible implementation, or when there is a long-term power gap in the power supply system of the target factory, using a lithium battery energy storage device for power supply further includes:

[0015] When the power generation of the new energy device is less than a preset second power generation amount, the power supply system of the target factory is in a long-term power gap;

[0016] Start the lithium battery energy storage device for power supply, and after a first preset time, control the flywheel energy storage device to withdraw from power supply.

[0017] In a possible implementation, the method further includes:

[0018] When there is a long-term power gap in the power supply system of the target factory, start the lithium battery energy storage device for power supply, and after a second preset time, control the flywheel energy storage device to withdraw from power supply; where the second preset time is determined based on the remaining power of the flywheel energy storage device.

[0019] In a possible implementation, the method further includes:

[0020] When the power change caused by the load change in the power supply system, the power supply system of the target factory is in a short-term power gap, and the flywheel energy storage device in the energy storage device is used for power supply.

[0021] In a possible implementation, the method further includes:

[0022] When the energy storage device is supplying power, if the remaining power of the energy storage device is less than the preset power, switch the power grid to supply power to the target factory;

[0023] Alternatively, the method may further include:

[0024] When the energy storage device supplies power, if the remaining power of the energy storage device is less than the preset power, switch the diesel generator set to supply power to the target factory.

[0025] In a possible implementation manner, the method may further include:

[0026] Charge the lithium battery energy storage device within a preset time period;

[0027] The daily charge-discharge cycle times of the lithium battery energy storage device are less than the first preset charge-discharge times;

[0028] The daily charge-discharge cycle times of the flywheel energy storage device are less than the second preset charge-discharge times.

[0029] In a possible implementation manner, the method may further include:

[0030] Monitor the bus voltage of the power grid;

[0031] When the bus voltage is less than or equal to the first preset voltage threshold, the flywheel energy storage device supplies power to provide power support;

[0032] When the bus voltage is greater than or equal to the second preset voltage threshold, start the lithium battery energy storage device to raise the bus voltage to the rated voltage.

[0033] In a second aspect, an embodiment of the present invention provides a power supply system for a low-carbon factory. The power supply system includes a new energy device, a waste heat and pressure power generation device, an energy storage device, and a microgrid energy management system; wherein, the energy storage device includes a flywheel energy storage device and a lithium battery energy storage device; when the target factory is in an operating state, the new energy device preferentially supplies power to the target factory. At the same time, the waste heat and pressure power generation device supplies power to the target factory based on the waste heat and pressure generated by the target factory;

[0034] The microgrid energy management system includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the method in the first aspect or any possible implementation manner of the first aspect as above.

[0035] In a possible implementation manner, the power supply system further includes a transformer, an LCL inverter, a bidirectional inverter, and a static synchronous compensator.

[0036] An embodiment of the present invention provides a power supply method for a low-carbon factory. In this method, new energy power supply is introduced. Under normal operation, new energy power supply is used in advance to make the factory achieve low-carbonization during operation. In this embodiment, since the introduction of new energy power supply will cause instability of the power supply system, therefore, a flywheel energy storage device is introduced in this embodiment, which has characteristics such as fast response speed, large instantaneous discharge electric power, and can adapt to high-frequency charge and discharge. When the voltage fluctuation or frequency fluctuation is not within the preset fluctuation range, the flywheel energy storage device is adopted. Through its characteristics of fast response speed and large instantaneous discharge electric power, it suppresses the voltage fluctuation and the frequency fluctuation of the power supply system, while maintaining the stable operation of the target factory, protecting the safety of each device in the power supply system. Furthermore, when the power supplied by the power supply system is less than the load of the target factory for a long time, the lithium battery energy storage device is switched to supply power, ensuring that the target factory can carry out normal production activities while reducing the power supply cost. Through the coordinated operation of new energy devices, lithium battery energy storage devices, and flywheel energy storage devices in this embodiment, it can effectively cope with the fluctuating load of the factory and the intermittency of new energy, and maintain the stability of the internal power grid of the factory. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is the architecture diagram of the power supply system of a low-carbon factory supported by the power grid provided by the embodiment of the present invention;

[0038] Figure 2 is the architecture diagram of the power supply system of a low-carbon factory without power grid support provided by the embodiment of the present invention;

[0039] Figure 3 is the implementation flowchart of the power supply method of the low-carbon factory provided by the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The following will describe the embodiments of the present invention in detail with reference to the accompanying drawings.

[0041] Figure 1 is the architecture diagram of the power supply system of a low-carbon factory supported by the power grid provided by the embodiment of the present invention, as Figure 1 shown, the power supply system is scheduled and controlled by the microgrid energy management system (EMS) therein. In addition to the microgrid energy management system, the power supply system may also include new energy devices, waste heat and pressure power generation devices, energy storage devices, transformers, LCL inverters, bidirectional inverters, static synchronous compensators, distributed photovoltaic generators in the factory, integrated energy storage and photovoltaic units, etc. Among them, the new energy devices may include wind power generation devices and photovoltaic power generation devices. Among them, the wind power generation device is connected to the 10KV bus of the power grid through an intelligent transformer, and the photovoltaic power generation device is connected to the 10KV bus of the power grid through an LCL inverter and an intelligent transformer.

[0042] In this power supply system, the energy storage device includes a flywheel energy storage device and a lithium battery energy storage device. The flywheel energy storage device and the lithium battery energy storage device are interconnected and are respectively connected to the 10 kV bus of the power grid through a power conversion system (PCS) and a transformer.

[0043] The remaining devices or factory loads are connected to the 10 kV bus of the power grid through a transformer.

[0044] In this embodiment, the flywheel energy storage compensates in real time for voltage sags / swells caused by sudden load changes, and STATCOM (Static Synchronous Compensator) can be configured as needed to provide dynamic reactive power support.

[0045] In this embodiment, due to the harmonic oscillation in the power grid, an LCL filter can also be installed at the new energy grid connection point to suppress the 3rd / 5th / 7th harmonics; at the same time, an active power filter (APF) can also be configured for non-linear loads such as frequency converters.

[0046] In this embodiment, when the target factory is in operation, the new energy device gives priority to supplying power to the target factory. At the same time, the waste heat and pressure power generation device supplies power to the target factory based on the waste heat and pressure generated by the target factory.

[0047] Since the waste heat and pressure power generation device is introduced into this power supply system and this device is a stable power supply unit, which uses the low-quality waste heat in the factory area or park for power generation, as long as the production runs normally, it can output stable electric power to supply power accordingly based on this device. However, the introduction of this device brings new problems, that is, when this device fails, how to maintain the voltage stability in the target factory.

[0048] To solve this problem, this application provides solutions in two scenarios. One is the scenario with the support of the State Grid, that is Figure 1 the scenario in, and the other is the scenario without the support of the State Grid. First, the Figure 1 scenario in will be explained below.

[0049] In the scenario with the support of the State Grid, when the waste heat and pressure power generation device fails, power can be directly supplied by the power grid to ensure normal production operation. After the waste heat and pressure power generation device is put back into use, the direct power supply from the power grid is then withdrawn.

[0050] Figure 2 is the architecture diagram of the power supply system of the low-carbon factory without power grid support provided by the embodiment of the present invention, that is, it is the scenario without the support of the State Grid and how to respond when the waste heat and pressure power generation device fails.

[0051] In Figure 2 In the provided scenario, the power supply system is in an island operation state. In this state, there is no power grid as a backup energy source to support the operation of the target factory. Therefore, a diesel generator set is introduced as a backup energy source. In this scenario, when the waste heat and pressure power generation equipment fails, the diesel generator set can supply power to fill the power gap and ensure normal production operation.

[0052] Of course, in actual operation, to ensure the safety of the power supply system, a diesel generator set can also be added as a backup energy source even when there is support from the national power grid.

[0053] Figure 3 It is the implementation flowchart of the power supply method for the low-carbon factory provided by the embodiments of the present invention. The control logic of the microgrid energy management system will be described below through Figure 3 and its related embodiments.

[0054] As Figure 3 shown, the method may include:

[0055] Step 110: Collect the frequency fluctuation and voltage fluctuation of the power supply system.

[0056] In this embodiment, the microgrid energy management system can collect the frequency and voltage in the power supply system in real time; and determine the frequency fluctuation and voltage fluctuation based on the collected frequency and voltage.

[0057] Step 120: When the frequency fluctuation is not within the preset frequency fluctuation range or the voltage fluctuation is not within the preset voltage fluctuation range, use a flywheel energy storage device for power supply.

[0058] In this embodiment, in the power supply system, due to the existence of impact loads, such as motors, when they start, it may cause frequency fluctuations. Frequency fluctuations within the normal range do not affect the normal operation of the power supply system, but when the frequency fluctuation is not within the preset frequency fluctuation range, it will affect the normal operation of the power supply system; among them, the preset frequency fluctuation range can be obtained by fitting historical data. Exemplarily, the preset frequency fluctuation range can be set to 50Hz ± 0.2Hz.

[0059] In this embodiment, similarly, due to the instability of new energy output, it may cause voltage fluctuations in the power supply system. Voltage fluctuations within the normal range do not affect the normal operation of the power supply system, but when the voltage fluctuation is not within the preset voltage fluctuation range, it will affect the normal operation of the power supply system; among them, the preset voltage fluctuation range can be obtained by fitting historical data. Exemplarily, the preset voltage fluctuation range can be set within ±5% of the rated voltage.

[0060] In this embodiment, when it is detected that the frequency fluctuation is not within the preset frequency fluctuation range or the voltage fluctuation is not within the preset voltage fluctuation range, the flywheel energy storage device has the characteristics of short-time and high-frequency regulation. Therefore, the flywheel energy storage device can be started to supply power to suppress voltage fluctuation and frequency fluctuation.

[0061] In this embodiment, when the frequency fluctuation is within the preset frequency fluctuation range and the voltage fluctuation is within the preset voltage fluctuation range, there is no need to start the energy storage device to supply power, and only the new energy device and the waste heat and pressure power generation device are used to supply power.

[0062] Step 130: When the power supply system of the target factory is in a long-term power gap, a lithium battery energy storage device is used to supply power; where the long-term power gap means that the power supply of the flywheel energy storage device is less than the difference between the power supply of the power supply system and the load of the target factory.

[0063] In this embodiment, the power supply system preferentially uses the new energy device to supply power. While operating, it will also use the waste heat and pressure power generation device to supply power to the target factory based on the waste heat and pressure generated by the target factory when the target factory is in an operating state, so as to make full use of the waste heat and pressure generated by the target factory and reduce the power supply cost.

[0064] That is, in this embodiment, when there is a difference between the power supply corresponding to the new energy device and the waste heat and pressure power generation device and the load of the target factory, and the power supply provided by the flywheel energy storage device is not sufficient to make up for this difference, it is necessary to start the lithium battery energy storage device to supply power to maintain the normal production of the target factory.

[0065] In summary, the embodiments of the present invention introduce new energy power supply. Under normal operation, new energy power supply is used in advance to make the factory achieve low-carbon operation during operation. In addition, waste heat and pressure power generation equipment is introduced in this embodiment. This equipment can make full use of the additional energy generated during the operation of the target factory and improve the energy utilization rate. In this embodiment, since the introduction of new energy power supply will cause instability in the power supply system, a flywheel energy storage device is introduced in this embodiment. It has characteristics such as fast response speed, large instantaneous discharge electric power, and can adapt to high-frequency charge and discharge. When the voltage of the power supply system fluctuates and is not within the preset voltage fluctuation range, or when the frequency of the power supply system fluctuates greatly, the flywheel energy storage device is used. Through its own characteristics of fast response speed and large instantaneous discharge electric power, it suppresses voltage fluctuations and the frequency fluctuations of the power supply system, while maintaining the stable operation of the target factory, protecting the safety of each device in the power supply system. Furthermore, when the power supplied by the power supply system is less than the load of the target factory for a long time, the lithium battery energy storage device is switched to supply power, ensuring that the target factory can carry out normal production activities while reducing the power supply cost. Through the coordinated operation of new energy equipment, lithium battery energy storage equipment, flywheel energy storage equipment, and waste heat and pressure power generation equipment, this embodiment can effectively cope with the fluctuating load of the factory and the intermittency of new energy, and maintain the stability of the internal power grid of the factory.

[0066] In an alternative embodiment, when the power supply system of the target factory is in a long-term power gap in step 130, using the lithium battery energy storage device to supply power may include:

[0067] When the power generation of the waste heat and pressure power generation equipment is less than the preset first power generation amount, the power supply system of the target factory is in a long-term power gap.

[0068] Start the lithium battery energy storage device to supply power, and after the first preset time, control the flywheel energy storage device to withdraw from power supply.

[0069] In this embodiment, after the first preset time, it may be the time when the frequency fluctuation and voltage fluctuation of the power supply system are within the corresponding preset ranges, or it may also be a fixed value set according to experience, which is not limited here.

[0070] In this embodiment, the long-term power gap state of the power supply system of the target factory may be caused by the waste heat and pressure power generation equipment. Theoretically, in order to prevent energy waste, the power supply amount of the new energy equipment, the power generation amount of the waste heat and pressure power generation equipment, and the load of the target factory should be in a balanced state. However, when the power generation amount of the waste heat and pressure power generation equipment is less than the preset first power generation amount, generally, it is due to the failure of the waste heat and pressure power generation equipment, or due to production and other reasons, the power generation amount of the waste heat and pressure power generation equipment is reduced, resulting in the power generation amount of the waste heat and pressure power generation equipment being less than the preset first power generation amount.

[0071] In this case, voltage fluctuations will occur. Therefore, the flywheel energy storage device will be started at this time. However, since the current is in a long-term power gap state, the flywheel energy storage device cannot maintain power supply for a long time. Therefore, it is necessary to start the lithium battery energy storage device for power supply and, after a first preset time, control the flywheel energy storage device to withdraw from power supply, enabling the lithium battery energy storage device to achieve stable power supply before the flywheel energy storage device withdraws, and avoiding large power output instantly generated by the lithium battery energy storage device after the flywheel energy storage device withdraws, which may cause damage to the device itself.

[0072] In addition, in this embodiment, the waste heat and pressure power generation device can perform fault prediction in advance based on the life prediction model to prepare corresponding control strategies in advance.

[0073] In an alternative embodiment, or when the power supply system of the target factory is in a long-term power gap in step 130, using the lithium battery energy storage device for power supply may further include:

[0074] When the power generation of the new energy device is less than the preset second power generation, the power supply system of the target factory is in a long-term power gap.

[0075] Start the lithium battery energy storage device for power supply and, after a first preset time, control the flywheel energy storage device to withdraw from power supply.

[0076] In this embodiment, the long-term power gap state of the power supply system of the target factory may also be caused by the new energy device. Due to weather changes or new energy device failures, the power generation of the new energy device is reduced, and the power provided cannot support the electricity demand of the target factory.

[0077] Similarly, in this case, voltage fluctuations will occur. Therefore, the flywheel energy storage device will be started at this time. However, since the current is in a long-term power gap state, the flywheel energy storage device cannot maintain power supply for a long time. Therefore, it is necessary to start the lithium battery energy storage device for power supply and, after a first preset time, control the flywheel energy storage device to withdraw from power supply, enabling the lithium battery energy storage device to achieve stable power supply before the flywheel energy storage device withdraws, and avoiding large power output instantly generated by the lithium battery energy storage device after the flywheel energy storage device withdraws, which may cause damage to the device itself.

[0078] In this embodiment, the long-term power gap caused by the new energy device can be predicted in advance based on the weather conditions to prepare corresponding control strategies in advance.

[0079] In an alternative embodiment, the method may further include:

[0080] When there is a long-term power gap in the power supply system of the target factory, start the lithium battery energy storage device to supply power, and after a second preset time, control the flywheel energy storage device to withdraw from power supply; wherein, the second preset time is determined based on the remaining power of the flywheel energy storage device.

[0081] In this embodiment, corresponding to the method provided in step 130, the method can also control the flywheel energy storage device to withdraw from power supply after the second preset time.

[0082] In this embodiment, since the flywheel energy storage device belongs to a short-term high-frequency energy storage device, the electricity stored in it is much less than that of the lithium battery energy storage device and cannot support long-term power supply. Therefore, the second preset time can be determined according to the remaining power of the flywheel energy storage device, and before or at the moment when the remaining power of the flywheel energy storage device is exhausted, control the flywheel energy storage device to withdraw from power supply.

[0083] In an optional embodiment, the method may further include:

[0084] When the power change caused by the load change in the power supply system, the power supply system of the target factory is in a short-term power gap, and the flywheel energy storage device in the energy storage device is used for power supply.

[0085] In this embodiment, the long-term power gap is regarded as an abnormal power state on the power supply side, while the power change caused by the load change in the power supply system is identified as a short-term power gap, which can be handled by the flywheel energy storage device. Therefore, it is only necessary for the flywheel energy storage device to respond preferentially for power supply.

[0086] In an optional embodiment, the method may further include:

[0087] When the energy storage device is supplying power, if the remaining power of the energy storage device is less than the preset power, switch the power grid to supply power to the target factory;

[0088] Or, the method may further include:

[0089] When the energy storage device is supplying power, if the remaining power of the energy storage device is less than the preset power, switch the diesel generator set to supply power to the target factory.

[0090] Since this solution can be applied to two scenarios with and without the support of the national power grid, when the remaining power of the energy storage device is insufficient, the power grid or the diesel generator set can be controlled to supply power according to the scenario corresponding to the power supply system.

[0091] In an optional embodiment, the method may further include:

[0092] Charge the lithium battery energy storage device within a preset time period;

[0093] The daily charge-discharge cycle times of the lithium battery energy storage device are less than the first preset charge-discharge times;

[0094] The daily charge-discharge cycle times of the flywheel energy storage device are less than the second preset charge-discharge times.

[0095] In this embodiment, when regulating each device in the power supply system, a reasonable optimal operation strategy needs to be formulated. During operation, in addition to ensuring normal production operation, economic efficiency also needs to be guaranteed and the service life of the device needs to be considered. Therefore, the lithium battery can be charged with low-price electricity during the valley electricity period of the power grid.

[0096] Furthermore, in order to ensure the service life of the device, for the lithium battery energy storage device, a shallow charge and shallow discharge strategy can be adopted to make the daily charge-discharge cycle times of the lithium battery energy storage device less than the first preset charge-discharge times. For example, only one charge-discharge cycle is performed per day; for the flywheel energy storage device, mechanical fatigue protection can be carried out to make its daily charge-discharge cycle times less than the second preset charge-discharge times, such as 200 times, etc.

[0097] In addition, in this embodiment, the power supply of the energy storage device and the power supply of the new energy device can also be switched according to a pre-determined switching point, where the switching point can be determined in the following manner:

[0098] According to the historical meteorological parameters of the target factory, the whole-year time period is divided into multiple periods, and the time point when the total power generation of wind and solar power generation drops suddenly in the current period is comprehensively predicted. Given that the change of photovoltaic power generation is the most regular compared with wind power generation, the daily change of photovoltaic power generation is used as the reference basis for the switching between the power supply of the wind and solar power plant and the long-term energy storage power supply within the period. For example: at 5 pm, due to the change of light intensity, the photovoltaic power generation drops rapidly, so a time point is selected for the switching between wind and solar power generation and energy storage power supply; at the same time, at 9 am the next day, the light resources have met the full-load power generation state of the photovoltaic power plant, and this time point is selected as the switching point between energy storage power supply and wind and solar power supply.

[0099] In an alternative embodiment, the method may further include:

[0100] Monitoring the bus voltage of the power grid.

[0101] When the bus voltage is less than or equal to the first preset voltage threshold, the flywheel energy storage device supplies power to provide power support.

[0102] When the bus voltage is greater than or equal to the second preset voltage threshold, the lithium battery energy storage device is started to raise the bus voltage to the rated voltage.

[0103] In this embodiment, the power supply system should also be provided with a protection and emergency file. For example, the bus voltage of the power grid can be monitored in real time. When the bus voltage is less than or equal to the first preset voltage threshold, the flywheel energy storage device is preferentially used for power supply to provide 1.1 times the rated power support to maintain the bus voltage. When the bus voltage is greater than or equal to the second preset voltage threshold, the lithium battery energy storage device is started to boost the bus voltage to the rated voltage.

[0104] In this embodiment, the first preset voltage threshold can be 70%, 69%, 68% of the rated voltage; the second preset voltage threshold can be 80%, 81%, 82% of the rated voltage, etc., and no specific limitation is made here.

[0105] In an alternative embodiment, this embodiment can also achieve power reallocation through the three-phase independent control of the power supply system to address the three-phase imbalance phenomenon.

[0106] In summary, the embodiment of the present invention provides a power supply method and system for a low-carbon factory. In this method, new energy power supply is introduced. Under normal operation, new energy power supply is used in advance to make the factory achieve low-carbonization during operation. In this embodiment, since the introduction of new energy power supply will cause instability of the power supply system, a flywheel energy storage device is introduced in this embodiment. It has characteristics such as fast response speed, large instantaneous discharge electric power, and can adapt to high-frequency charge and discharge. When the voltage fluctuation or frequency fluctuation is outside the preset fluctuation range, the flywheel energy storage device is used. Through its own characteristics of fast response speed and large instantaneous discharge electric power, it suppresses the voltage fluctuation of the new energy device and the frequency fluctuation of the power supply system, while maintaining the stable operation of the target factory and protecting the safety of each device in the power supply system. Furthermore, when the power supplied by the power supply system is less than the load of the target factory for a long time, the lithium battery energy storage device is switched to supply power to ensure that the target factory can carry out normal production activities while reducing the power supply cost. Through the coordinated operation of the new energy device, the lithium battery energy storage device, and the flywheel energy storage device in this embodiment, it can effectively cope with the fluctuating load of the factory and the intermittency of new energy, and maintain the stability of the internal power grid of the factory.

[0107] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0108] In the above embodiments, the descriptions of each embodiment have their own emphases. For the parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments. Without special instructions and logical conflicts, the terms and / or descriptions between different embodiments are consistent and can be mutually referred to. The technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships.

[0109] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A power supply method for a low-carbon factory, characterized in that, A microgrid energy management system applied to the power supply system of a target factory, the power supply system including new energy equipment and energy storage equipment; wherein, the energy storage equipment includes a flywheel energy storage device and a lithium battery energy storage device; when the target factory is in an operating state, the new energy equipment preferentially supplies power to the target factory; the method includes: Collect the frequency fluctuation and voltage fluctuation of the power supply system; When the frequency fluctuation is not within the preset frequency fluctuation range, or the voltage fluctuation is not within the preset voltage fluctuation range, use the flywheel energy storage device to supply power; When the power supply system of the target factory is in a long-term power gap, use the lithium battery energy storage device to supply power; wherein, the long-term power gap means that the power supply amount of the flywheel energy storage device is less than the difference between the power supply amount of the power supply system and the load amount of the target factory.

2. The power supply method of the low-carbon factory according to claim 1, characterized in that, The power supply system further includes waste heat and pressure recovery power generation equipment; the waste heat and pressure recovery power generation equipment supplies power to the target factory based on the waste heat and pressure generated by the target factory when the target factory is in an operating state; The step of using the lithium battery energy storage device to supply power when the power supply system of the target factory is in a long-term power gap includes: When the power generation amount of the waste heat and pressure recovery power generation equipment is less than the preset first power generation amount, the power supply system of the target factory is in a long-term power gap; Start the lithium battery energy storage device to supply power, and after a first preset time, control the flywheel energy storage device to stop supplying power.

3. The power supply method of the low-carbon factory according to claim 1, characterized in that, Or, the step of using the lithium battery energy storage device to supply power when the power supply system of the target factory is in a long-term power gap further includes: When the power generation amount of the new energy equipment is less than the preset second power generation amount, the power supply system of the target factory is in a long-term power gap; Start the lithium battery energy storage device to supply power, and after a first preset time, control the flywheel energy storage device to stop supplying power.

4. The power supply method of the low-carbon factory according to claim 2 or 3, characterized in that, The method further includes: When the power supply system of the target factory is in a long-term power gap, start the lithium battery energy storage device to supply power, and after a second preset time, control the flywheel energy storage device to stop supplying power; wherein, the second preset time is determined based on the remaining power of the flywheel energy storage device.

5. The power supply method of the low-carbon factory according to claim 1, characterized in that, The method further includes: When the power change caused by the load change in the power supply system, the power supply system of the target factory is in a short-term power gap, and use the flywheel energy storage device in the energy storage equipment to supply power.

6. The power supply method of the low-carbon factory according to claim 1, characterized in that, The method further includes: When the energy storage device supplies power, if the remaining power of the energy storage device is less than the preset power, switch the power grid to supply power to the target factory; Or, the method further includes: When the energy storage device supplies power, if the remaining power of the energy storage device is less than the preset power, switch the diesel generator set to supply power to the target factory.

7. The power supply method of the low-carbon factory according to claim 1, characterized in that The method further includes: Charge the lithium battery energy storage device within a preset time period; The daily charge and discharge cycle times of the lithium battery energy storage device are less than the first preset charge and discharge times; The daily charge and discharge cycle times of the flywheel energy storage device are less than the second preset charge and discharge times.

8. The power supply method of the low-carbon factory according to claim 1, wherein The method further includes: Monitor the bus voltage of the power grid; When the bus voltage is less than or equal to the first preset voltage threshold, the flywheel energy storage device supplies power to provide power support; When the bus voltage is greater than or equal to the second preset voltage threshold, the lithium battery energy storage device is started to boost the bus voltage to the rated voltage.

9. A power supply system for a low-carbon factory, characterized in that, The power supply system includes a new energy device, a waste heat and pressure power generation device, an energy storage device, and a microgrid energy management system; wherein, the energy storage device includes a flywheel energy storage device and a lithium battery energy storage device; when the target factory is in an operating state, the new energy device preferentially supplies power to the target factory, and at the same time, the waste heat and pressure power generation device supplies power to the target factory based on the waste heat and pressure generated by the target factory; The microgrid energy management system includes a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, the method described in any one of claims 1 to 8 is implemented.

10. The power supply system of the low-carbon factory according to claim 9, characterized in that, The power supply system further includes a transformer, an LCL inverter, a bidirectional inverter, and a static synchronous compensator.

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