A park power quality collaborative management system and method

Abstract

Multiple embodiments of this specification relate to the field of energy technologies, and more particularly to a system and method for collaborative power quality governance in a park. The system includes monitoring devices, several energy storage converters, active power filters, and control devices. The energy storage converter includes a cabinet for accommodating devices therein, and a cabinet controller, an inverter, an energy storage battery, an energy storage element, a voltage stabilizing module, and a voltage transformation module provided in the cabinet. An input junction box, a DC output junction box, an AC output junction box, and a communication device are installed on the cabinet. The energy storage battery and the energy storage element are connected through a bidirectional charging circuit. The energy storage element is connected to the input connection box by an adaptive charging circuit provided in the cabinet. The AC output junction box is connected to the energy storage element by an inverter provided in the cabinet. The DC output junction box is connected to the energy storage battery through the voltage stabilizing module and the voltage transformation module provided in the cabinet. The input end of the active power filter is powered by the inverter of one energy storage converter.

Description

Technical Field

[0001] Multiple embodiments of this specification relate to the field of energy technology, and more particularly to a system and method for collaborative power quality governance in an industrial park. Background Art

[0002] With the acceleration of the industrialization process, in order to solve many problems in industrial development, such as low land use efficiency, environmental pollution, low resource utilization efficiency, etc. Industrial parks concentrate a large number of industrial enterprises in one area, so that infrastructure construction can be centralized and these problems can be solved or reduced through intensive management. It is of great significance for promoting economic development, optimizing resource allocation, and enhancing industrial competitiveness. Through planning and management, industrial parks can achieve efficient utilization of resources such as land, electricity, and manpower. And it can carry out specialized planning and construction in combination with the characteristics of industrial parks to provide higher-quality services. For power supply, the loads in industrial parks are usually relatively complex, including a large number of LED lighting, variable frequency drive equipment, and other non-linear loads, which will all generate harmonic pollution. The instability of the loads in the park will cause problems such as voltage fluctuations and frequency changes. Therefore, it is necessary to study the power governance technology for industrial parks. Summary of the Invention

[0003] Multiple embodiments of this specification describe a system and method for collaborative power quality governance in an industrial park.

[0004] In a first aspect, embodiments of this specification provide a system for collaborative power quality governance in an industrial park, including monitoring equipment, several energy storage converters, active power filters, and control equipment.

[0005] The monitoring equipment monitors the voltage, frequency, and harmonics of the power supply loop network in the industrial park.

[0006] Several of the energy storage converters are respectively connected to several power supply branches. The energy storage converter includes a cabinet for accommodating devices therein, and a cabinet controller, an inverter, an energy storage battery, an energy storage element, a voltage stabilizing module, and a voltage transformation module provided in the cabinet. An input wiring box, a DC output wiring box, an AC output wiring box, and a communication device are installed on the cabinet.

[0007] The energy storage battery is connected to the energy storage element through a bidirectional charging circuit. The energy storage element is connected to the input connection box by an adaptive charging circuit provided in the cabinet. The input wiring box is connected to the external power supply. The AC output wiring box is connected to the load. The AC output wiring box is connected to the energy storage element by an inverter provided in the cabinet. The DC output wiring box is connected to the energy storage battery through a voltage stabilizing module and a voltage transformation module provided in the cabinet. A cabinet monitoring device is provided in the cabinet, and the cabinet monitoring device monitors the temperature and humidity inside the cabinet, and the working states of the energy storage battery and the energy storage element.

[0008] The input end of the active power filter is powered by the inverter of an energy storage converter cabinet. When the voltage and frequency of the power supply ring network exceed the preset threshold fluctuations, the controller in the cabinet controls the energy storage converter cabinet to suppress the voltage and frequency fluctuations of the power supply ring network.

[0009] In a second aspect, an embodiment of the present specification provides a method for collaborative management of power quality in a park, including the steps of:

[0010] It includes setting up monitoring devices, several energy storage converter cabinets, active power filters and control devices. The monitoring devices monitor the voltage, frequency and harmonics of the power supply ring network in the park;

[0011] Configure several of the energy storage converter cabinets to be respectively connected to several power supply branches. The energy storage converter cabinet includes a cabinet body for accommodating devices inside it, and a controller in the cabinet, an inverter, an energy storage battery, an energy storage element, a voltage stabilizing module and a voltage transformation module are arranged inside the cabinet. An input junction box, a DC output junction box, an AC output junction box and a communication device are installed on the cabinet body;

[0012] Connect the energy storage battery and the energy storage element through a bidirectional charging circuit. The energy storage element is connected to the input connection box by an adaptive charging circuit arranged inside the cabinet. The input junction box is connected to the external power supply. The AC output junction box is connected to the load. The AC output junction box is connected to the energy storage element by an inverter arranged inside the cabinet. The DC output junction box is connected to the energy storage battery through a voltage stabilizing module and a voltage transformation module arranged inside the cabinet. An in-cabinet monitoring device is arranged inside the cabinet, and the in-cabinet monitoring device monitors the temperature and humidity inside the cabinet, and the working states of the energy storage battery and the energy storage element;

[0013] Configure the input end of the active power filter to be powered by the inverter of an energy storage converter cabinet;

[0014] When the voltage and frequency of the power supply ring network exceed the preset threshold fluctuations, the controller in the cabinet controls the energy storage converter cabinet to suppress the voltage and frequency fluctuations of the power supply ring network.

[0015] The beneficial effects brought by the technical solutions provided in some embodiments of the present specification at least include:

[0016] In multiple embodiments of the present specification, the collaborative power quality management system provided in the park can manage the harmonics in the power supply ring network through an active power filter, which helps the normal operation of electronic devices in the park. By suppressing the peak-valley difference of the distribution network through the energy storage converter cabinet, it helps to improve the stability of the distribution network and ensure the power supply safety of the park. By matching the energy storage converter cabinet with photovoltaic panels, it can suppress the fluctuations of photovoltaic power generation output, reduce light curtailment and improve the power quality of the power supply ring network.

[0017] Other features and advantages of multiple embodiments of this specification will be further revealed in the following detailed implementation manners and drawings. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the embodiments of this specification, the drawings required for the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of this specification. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 Schematic diagram of the park power supply structure provided for the embodiments of this specification.

[0020] Figure 2 Schematic diagram of the structure of the energy storage converter cabinet provided for the embodiments of this specification.

[0021] Figure 3 Schematic diagram of the electrical connection of the energy storage converter cabinet provided for the embodiments of this specification.

[0022] Figure 4 Schematic diagram of the circuit connection principle of the energy storage converter cabinet provided for the embodiments of this specification.

[0023] Figure 5 Schematic diagram of the method for generating an on-line regulation command provided for the embodiments of this specification.

[0024] Figure 6 Schematic diagram of the method for suppressing voltage and frequency fluctuations provided for the embodiments of this specification. Detailed Implementation Manner

[0025] The technical solutions in the embodiments of this specification will be explained and illustrated below with reference to the drawings of the embodiments of this specification. However, the following embodiments are only the preferred embodiments of this specification, not all of them. Based on the embodiments in the implementation manner, other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of this specification.

[0026] The terms "first", "second", "third", etc. in the specification, claims and the above drawings of this specification are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally further include steps or units not listed, or may optionally further include other steps or units inherent to these processes, methods, products or devices.

[0027] In the following description, terms such as "inside", "outside", "up", "down", "left", "right", etc. that indicate directions or positional relationships are only used to facilitate the description of the embodiments and simplify the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation of this specification.

[0028] The data involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection of relevant data complies with the relevant laws, regulations and standards of relevant countries and regions.

[0029] Before describing the technical solution in this specification, an introduction is given to the application scenarios and related technologies of the technical solution.

[0030] The accelerated industrialization process has led to a series of problems, including inefficient land use, serious environmental pollution, and waste of resources. Industrial parks can achieve intensive production and environmental protection through unified planning and management. Centralized treatment of industrial waste can reduce environmental pollution. Through centralized management, resource allocation can be optimized and production efficiency can be improved. Infrastructure such as roads, water and power supply, and communication networks within the park can be shared, reducing the cost of individual construction for each enterprise. By installing advanced waste gas treatment equipment and technology, the emission of harmful gases can be reduced.

[0031] The industrial park will also use clean energy, such as solar energy and wind energy, to reduce the use of fossil fuels. Figure 1 , install solar photovoltaic panels 102 on the roof of the park or other open areas to generate electricity using solar energy. This method can not only meet part of the park's own electricity needs, but also sell excess electricity to power grid companies. Install wind turbines in areas with abundant wind resources to convert wind energy into electrical energy. It is suitable for open areas or areas with strong winds such as the seaside. Due to the unstable supply of natural energy such as solar energy and wind energy, this poses a challenge to the stable operation of the power grid. At present, the park uses a ring network cabinet 101 with higher power supply stability as the main power supply method. The ring network cabinet 101 forms a power supply ring network, and the outgoing line of each ring network cabinet 101 is connected to a power supply branch 104, and the load 105 of the park is connected to the power supply branch 104.

[0032] There are also a large number of nonlinear loads105 (such as inverters, switching power supplies, etc.) in the industrial park. These devices generate harmonic currents, causing distortion of the grid voltage waveform. When high-power equipment starts or stops, it causes voltage fluctuations, affecting the normal operation of sensitive equipment, especially for precision instruments and automated production lines. Fluctuations in grid frequency can affect the stability of motor speed and have an adverse effect on the production process. Due to external grid failures or other factors, the park may experience a brief voltage drop or complete interruption, which is particularly detrimental to the process of continuous production.

[0033] Therefore, the power management of industrial parks is a key task for the parks. Good power quality can ensure the normal operation of production equipment, extend the service life of the equipment, and reduce maintenance and replacement costs. Power quality problems may lead to production interruptions, product quality degradation, etc., thereby causing economic losses. These losses can be avoided by improving power quality.

[0034] The energy storage converter system can store excess power and release the stored power during peak power demand periods or when renewable energy generation is insufficient, so as to balance power supply and demand and enhance the overall stability of the power grid. In addition, the energy storage converter system helps improve power quality, reduce power losses, and in some cases, can also serve as the core component of a microgrid to achieve power autonomy within a local area. Please refer to the appendix Figure 2 , which is a relatively common application type of the current energy storage converter system. That is, it is installed in a cabinet 10 similar to a container, and the battery and related equipment are all installed in the cabinet 10. It has the characteristics of convenient transportation. And it can be directly placed in an outdoor open space without the need to build a dedicated building or divide space indoors for it. Deployment and commissioning can be completed by wiring through the cable interface outside the cabinet 10.

[0035] A park is an area with a certain scale, clear functional positioning, and intensive management, usually including various types such as industrial parks, science and technology parks, and logistics parks. There are a large number of enterprises in the park, often involving enterprises with large energy demands. At the same time, the park itself also has relatively high energy management requirements. With the popularization of the concept of sustainable development and the progress of technology, many parks have begun to deploy containerized energy storage converter systems in the park, which can play a role in energy conservation, emission reduction, improving energy utilization efficiency, and exploring new energy. Specifically, the electricity demand in the park changes over time and seasons. The energy storage system can store excess power during low-demand periods and release it during peak-demand periods, thus balancing the power supply and demand in the park and reducing the pressure on the power grid. The energy storage system can also serve as a backup emergency power source to provide emergency power support in case of emergencies, ensuring continuous operation in the park, which is crucial especially for key equipment and services. Combined with an intelligent management system, the energy storage system can monitor and adjust energy distribution in real time to maximize the utilization of renewable energy in the park, such as the power generated by solar photovoltaic panels 102. By cutting peaks and filling valleys, the park can also store power when the electricity price is low and use the stored power when the electricity price is high, thereby saving electricity costs. In addition, some parks may also enjoy subsidy or reward policies for energy storage projects from relevant competent departments.

[0036] Energy storage systems are one of the important tools for achieving energy structure adjustment, contributing to the low-carbon and environmentally friendly development of industrial parks and aligning with the country's sustainable development strategy. Deploying containerized energy storage converter systems within industrial parks can not only address the energy management issues faced by the parks themselves but also drive the optimization and upgrading of the energy structure in the entire region and even a wider area. It is an important part of realizing the construction of green and intelligent industrial parks. However, energy storage systems also have some drawbacks, such as high initial investment, high maintenance costs and technical requirements, and efficiency losses during the energy conversion process. Secondly, the battery life of energy storage devices is limited and needs to be replaced regularly. Moreover, if not handled properly, when the control of the energy storage converter system in the industrial park is improper, it will cause the battery to frequently switch between the charging and discharging states, further reducing the life and stability of the energy storage converter system. Therefore, this specification discusses the improved technologies for energy storage converter systems used in industrial parks.

[0037] In view of the fact that this application will involve some professional terms, therefore, the following will first introduce these professional terms.

[0038] Energy storage battery

[0039] Energy storage batteries are devices used to store electrical energy and release it when needed. They are widely used in multiple fields such as households, industries, and power grids to achieve functions such as stable power supply, peak shaving and valley filling, and backup power supply. Energy storage batteries 31 can be classified into various types according to their chemical composition, usage purpose, and scale. Lithium-ion batteries, lead-acid batteries, sodium-sulfur batteries, flow batteries, nickel-cadmium batteries, and nickel-metal hydride batteries. As an important energy management tool, energy storage batteries 31 play an indispensable role in industrial parks and other application scenarios. With the progress of technology and the decline in costs, the application scope of energy storage batteries 31 will continue to expand and become one of the key factors in realizing smart grids and promoting energy transformation.

[0040] Energy storage element

[0041] Energy storage elements refer to devices or components that can store energy within a certain period of time and release this energy when needed. Energy storage elements 32 are widely used in multiple fields such as power systems, electronic devices, and transportation. Common energy storage elements 32 mainly include capacitors (including supercapacitors), flywheel energy storage devices, etc. In the industrial park environment, energy storage elements 32 can be flexibly configured according to specific needs. For example, supercapacitors can be used to provide instant large current demands and are suitable for equipment with frequent starts and stops. Flywheel energy storage devices can serve as a fast-response backup power supply to ensure that key facilities in the industrial park can still operate when the power grid is interrupted. Relatively speaking, using supercapacitors as energy storage elements 32 can achieve better results.

[0042] This specification first provides a collaborative power quality governance system for a park. The park includes a power supply ring network and several power supply branches 104, and includes monitoring equipment, several energy storage converters, active power filters, and control equipment.

[0043] The monitoring equipment monitors the voltage, frequency, and harmonics of the power supply ring network of the park.

[0044] Several of the energy storage converters are respectively connected to several power supply branches 104. Please refer to the appendix Figure 3 , The energy storage converter includes a cabinet for accommodating devices inside it, and a cabinet controller, an inverter, an energy storage battery, an energy storage element, a voltage stabilizing module, and a voltage transformation module arranged inside the cabinet. An input wiring box, a DC output wiring box, an AC output wiring box, and a communication device are installed on the cabinet.

[0045] The energy storage battery is connected to the energy storage element through a bidirectional charging circuit. The energy storage element is connected to the input connection box by an adaptive charging circuit arranged inside the cabinet. The input wiring box is connected to an external power supply. The AC output wiring box is connected to a load 105. The AC output wiring box is connected to the energy storage element by an inverter arranged inside the cabinet. The DC output wiring box is connected to the energy storage battery through a voltage stabilizing module and a voltage transformation module arranged inside the cabinet. The input wiring box 11, the DC output wiring box 121, and the AC output wiring box 122 can be realized by using the technologies disclosed in the art, and can be implemented as long as they have the function of establishing an electrical connection.

[0046] A cabinet monitoring device is arranged inside the cabinet. The cabinet monitoring device monitors the temperature and humidity inside the cabinet, and the working states of the energy storage battery and the energy storage element. The input end of the active power filter is powered by the inverter of an energy storage converter. When the voltage and frequency of the power supply ring network fluctuate beyond a preset threshold, the cabinet controller controls the energy storage converter to suppress the voltage and frequency fluctuations of the power supply ring network.

[0047] A cabinet monitoring device 41 is arranged inside the cabinet 10. The cabinet monitoring device 41 monitors the temperature and humidity inside the cabinet 10, the power of the energy storage battery 31, the power of the energy storage element 32, the voltage of the energy storage battery 31, the voltage of the energy storage element 32, the current of the energy storage battery 31, the current of the energy storage element 32, and the voltage of the external power supply inside the cabinet. The bidirectional charging circuit 22, the adaptive charging circuit 21, the inverter 42, the cabinet monitoring device 41, and the communication device are all connected to the controller.

[0048] The voltage, frequency and harmonics of the power supply ring network can be monitored and obtained by monitoring equipment. When there are many harmonics in the power supply ring network, the active power filter can generate opposite harmonics and inject them into the power supply ring network, thereby suppressing the harmonics and improving the power quality of the power supply ring network. The active power filter can be implemented using the technology disclosed in the art. The active power filter can be powered by the power supply ring network, by the inverter of the energy storage converter cabinet, or by the energy storage battery of the energy storage converter.

[0049] The energy storage battery 31 establishes a distributed energy storage system to help the park to achieve peak shaving and valley filling and smooth the load curve. The energy storage element 32 can meet the power demand of special equipment in the park. For equipment with frequent power fluctuations, the energy storage element 32 can smooth its fluctuations, which is beneficial to improving the power supply quality of the park. The bidirectional charging circuit 22 can exchange energy between the energy storage battery 31 and the energy storage element 32. When there is photovoltaic power generation equipment in the park, when the photovoltaic power generation equipment charges the energy storage battery 31, if constant current charging is used, it is easy to cause fluctuations in the park's distribution network or cause obvious problems of abandoned light. The use of energy storage elements 32 can achieve constant current charging, protect the energy storage battery 31, and at the same time can smooth the output fluctuations of photovoltaic power generation equipment, reduce the fluctuation pressure of the park's distribution network, and improve the power supply quality of the park.

[0050] For details, please refer to the attached Figure 4 , the adaptive charging circuit 21 includes a DC charging circuit, an AC charging circuit and a detection module, the detection module detects the voltage and type of the external power supply, when the external power supply is a DC power supply, the DC charging circuit charges the energy storage element 32, when the external power supply is an AC power supply, the AC charging circuit charges the energy storage element 32, the input junction box 11 also includes a photovoltaic input module, a mains input module and a switching device, the photovoltaic input module is connected to the external photovoltaic panel 102, the mains input module is connected to the power supply ring network, and the adaptive charging circuit 21 is connected to the photovoltaic input module and the mains input module through the switching device. When the park is equipped with photovoltaic power generation equipment and the output of the photovoltaic power generation equipment is greater than the preset threshold value, the photovoltaic power generation equipment supplies power to the park's load 105 through the energy storage converter box provided in this embodiment, rather than directly supplying power to the park's load 105. When the output of the photovoltaic power generation equipment is not greater than the power of the park's load 105, the photovoltaic power generation equipment charges the energy storage element 32 through the connected DC charging circuit, and transfers the electric energy generated by the photovoltaic power generation equipment to the energy storage element 32.

[0051] The energy storage element 32 powers the inverter 42. When the inverter 42 completes voltage boosting and is phase-locked with the power grid, it generates alternating current to power the campus load 105. The energy storage element 32 features fast charging and discharging, capable of suppressing the fluctuations in the output of the photovoltaic power generation device and ensuring stable power supply to the inverter 42. For example, when the energy storage element 32 uses a supercapacitor, the power generated by the photovoltaic power generation device charges the supercapacitor, and the voltage of the supercapacitor slightly increases. At this time, according to the existing technology, a voltage stabilizing circuit 43 is equipped to stabilize the voltage and then supply it to the inverter 42 to work, which can ensure the stable input voltage of the inverter 42. When the power generated by the photovoltaic power generation device is low or the campus load 105 suddenly increases, the voltage of the supercapacitor will slightly decrease, but through the voltage stabilizing effect of the voltage stabilizing circuit 43, the stable input voltage of the inverter 42 can still be ensured.

[0052] When the output of the photovoltaic power generation device is greater than the campus load 105, the photovoltaic power generation device charges the energy storage element 32 through the DC charging circuit. After the energy storage element 32 powers the inverter 42 and generates power for the campus load 105, there is still remaining power. At this time, the energy storage element 32 will supply its power to the energy storage battery 31 through the bidirectional charging circuit 22. The bidirectional charging circuit 22 charges in a constant current mode or a constant voltage mode. When the output of the photovoltaic power generation device slightly increases, the energy storage element 32 will store more power, but the voltage increase of the energy storage element 32 is not significant. When the output of the photovoltaic power generation device slightly decreases, the energy storage element 32 will store less power, but the voltage drop of the energy storage element 32 is also not significant. This ensures that the bidirectional charging circuit 22 can work stably and at the same time realizes constant current charging or constant voltage charging of the energy storage battery 31, which helps to protect the energy storage battery 31 and extend its lifespan.

[0053] When the photovoltaic power generation device has no output or the output is lower than the threshold power, the power grid is used to power the campus load 105. However, if the energy storage battery 31 stores a large amount of power at this time, or it is currently during the peak power consumption period of the power grid, the energy storage battery 31 is used to charge the energy storage element 32, and then the energy storage element 32 powers the inverter 42 to generate alternating current that can share the campus load 105, alleviating the peak power consumption pressure on the power grid.

[0054] Specifically, the bidirectional charging circuit 22 includes a forward charging circuit 221 and a reverse charging circuit 222. The forward charging circuit 221 uses the power of the energy storage battery 31 to charge the energy storage element 32, and the reverse charging circuit 222 uses the power of the energy storage element 32 to charge the energy storage battery 31. The controller reads the power of the energy storage element 32. When the power of the energy storage element 32 is higher than a preset first threshold, it controls the reverse charging circuit 222 to work until the power of the energy storage element 32 is lower than a preset second threshold. When the power of the energy storage element 32 is lower than a preset fourth threshold, the controller controls the forward charging circuit 221 to work until the power of the energy storage element 32 is higher than a preset third threshold.

[0055] As the power stored in the energy storage element 32 is gradually delivered to the energy storage battery 31 by the reverse charging circuit 222, when the power of the energy storage element 32 gradually drops below the second threshold, the reverse charging circuit 222 is controlled to stop working. If at this time, the output power of the photovoltaic power generation device is still relatively high, in addition to supplying the load 105, it will also charge the energy storage element 32 until it returns to a state where the power exceeds the first threshold. At this time, the charging of the energy storage battery 31 can be restarted, that is, the reverse charging circuit 222 is restarted. In this way, when the output power of the photovoltaic power generation device is relatively large, in addition to supplying the user load 105, it charges the energy storage battery 31.

[0056] When the output power of the photovoltaic power generation device is small, such as on cloudy days or at night, the power of the energy storage element 32 will decrease due to being used by the load 105 of the user. When the power of the energy storage element 32 drops below the fourth threshold, it indicates that the power of the energy storage element 32 is relatively low. At this time, the forward charging circuit 221 is made to work, and the power of the energy storage battery 31 will charge the energy storage element 32 through the forward charging circuit 221, causing the power of the energy storage element 32 to gradually rise and reach the third threshold. At this time, the forward charging circuit 221 is controlled to stop working. Then, if the output power of the photovoltaic power generation device is still low, or the power of the user's load 105 is large, the power of the energy storage element 32 will be gradually consumed until it is lower than the fourth threshold again.

[0057] Among them, the controller periodically calculates the charge and discharge power of the energy storage element 32 until the power of the energy storage element 32 is lower than the preset fourth threshold, calculates the equivalent discharge power of the energy storage element 32 during the period when the power drops from the third threshold to the fourth threshold, and the controller calculates the ratio of the equivalent discharge power to the preset reference discharge power. When the ratio is greater than 1, the square of the ratio is calculated as the adjustment coefficient, and the third threshold is adjusted to the product of the preset initial threshold and the adjustment coefficient. When the ratio is not greater than 1, the third threshold is adjusted to the preset initial threshold. The controller controls the forward charging circuit 221 to work until the power of the energy storage element 32 reaches the preset third threshold. According to the park load 105, the third threshold is dynamically adjusted to reduce the number of switching times of the forward charging circuit 221 in the working or stopping state, ensuring a more stable power supply and helping to ensure the life of the energy storage battery 31.

[0058] On the other hand, when the controller calculates the equivalent discharge power during the period when the electric quantity of the energy storage element 32 decreases from the third threshold value to the fourth threshold value, the controller performs the following steps:

[0059] The read charge and discharge power of the energy storage element 32 is compared with the preset reference power, and after deleting the charge and discharge power that is less than the preset reference power, the average value of the remaining charge and discharge power is calculated as the equivalent discharge power.

[0060] On the other hand, in another embodiment, the system further includes a server, the communication device is communicatively connected to the server, the controller reports the data monitored by the cabinet monitoring device 41 to the server through the communication device, and the server runs a remote control interface and a report interface, the report interface displays the data monitored by the cabinet monitoring device 41, and the remote control interface is used to receive user control instructions for the controller. The server in this specification can be an independent physical server, or a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, content distribution networks, and big data and artificial intelligence platforms.

[0061] Among them, the server runs an online control module, and the online control module generates online control instructions based on the data reported by the controllers of multiple energy storage inverter cabinets 103. The online control instructions are executed by the controllers of multiple energy storage inverter cabinets 103, and multiple energy storage inverter cabinets 103 are connected to the same load 105 and the same external power supply.

[0062] Specifically, when the online control module generates an online control instruction according to the data reported by the controllers of the multiple energy storage converter cabinets 103, please refer to the attached Figure 5 , perform the following steps:

[0063] Step S101) obtaining the power of the energy storage battery 31 of each energy storage converter cabinet 103;

[0064] Step S102) When the load 105 exceeds a preset high threshold, the inverter 42 of the energy storage converter cabinet 103 whose power level of the energy storage battery 31 is higher than a first reference power level is controlled to operate to supply power to the load 105;

[0065] Step S103 ) When the load 105 is lower than a preset low threshold, the adaptive charging circuit 21 of the energy storage converter cabinet 103 controls the power level of the energy storage battery 31 to be lower than a second reference power level to operate and charge the energy storage battery 31 .

[0066] By controlling the online energy storage converter cabinet 103, when the park load 105 is high, the energy storage converter cabinet 103 with more stored electricity is used to preferentially supply power to the park load 105. When the park load 105 is low, such as when the power grid is in a low period, the energy storage converter cabinet 103 with less stored electricity is preferentially charged to achieve online control.

[0067] On the other hand, please see the attached Figure 6 When the in-cabinet controller controls the energy storage converter cabinet to smooth the voltage and frequency fluctuations of the power supply ring network, the following steps are performed:

[0068] Step S201) calculating the voltage deviation value and the frequency deviation value of the power supply ring network, and generating the adjustment power according to the voltage deviation value and the frequency deviation value;

[0069] Step S202) When the voltage or frequency of the power supply ring network is low, the in-cabinet controller controls the inverter to supply power to the power supply ring network with the adjusted power;

[0070] Step S203) When the voltage or frequency of the power supply ring network is high, the in-cabinet controller controls the adaptive charging circuit to charge the energy storage element with the adjusted power.

[0071] The technology for generating adjustment power according to the voltage deviation value and the frequency deviation value has been disclosed in the art. For example, it can be referred to the adjustment scheme of the power plant for the output of the generator set.

[0072] On the other hand, this specification provides a method for collaboratively managing power quality in a park, including the steps of:

[0073] It includes a monitoring device, several energy storage converters, an active power filter and a control device. The monitoring device monitors the voltage, frequency and harmonics of the power supply ring network in the park.

[0074] Configure several of the energy storage converters to be respectively connected to several power supply branches 104. The energy storage converter includes a cabinet for accommodating devices therein, and a cabinet controller, an inverter, an energy storage battery, an energy storage element, a voltage stabilizing module and a voltage transformation module arranged in the cabinet. An input wiring box, a DC output wiring box, an AC output wiring box and a communication device are installed on the cabinet.

[0075] Connect the energy storage battery and the energy storage element through a bidirectional charging circuit. The energy storage element is connected to the input connection box by an adaptive charging circuit arranged in the cabinet. The input wiring box is connected to an external power supply. The AC output wiring box is connected to a load. The AC output wiring box is connected to the energy storage element by an inverter arranged in the cabinet. The DC output wiring box is connected to the energy storage battery through a voltage stabilizing module and a voltage transformation module arranged in the cabinet. A cabinet monitoring device is arranged in the cabinet, and the cabinet monitoring device monitors the temperature and humidity in the cabinet, and the working states of the energy storage battery and the energy storage element.

[0076] Configure the input end of the active power filter to be powered by the inverter of an energy storage converter.

[0077] When the voltage and frequency of the power supply ring network fluctuate beyond a preset threshold, the cabinet controller controls the energy storage converter to suppress the voltage and frequency fluctuations of the power supply ring network.

[0078] On the other hand, in another embodiment, the bidirectional charging circuit is set to include a forward charging circuit and a reverse charging circuit. The forward charging circuit uses the power of the energy storage battery to charge the energy storage element, and the reverse charging circuit uses the power of the energy storage element to charge the energy storage battery.

[0079] Read the power of the energy storage element. When the power of the energy storage element is higher than a preset first threshold, control the reverse charging circuit to work until the power of the energy storage element is lower than a preset second threshold.

[0080] When the power of the energy storage element is lower than a preset fourth threshold, the controller controls the forward charging circuit to work until the power of the energy storage element is higher than a preset third threshold.

[0081] On the other hand, in another embodiment, the method for collaborative governance of power quality in the park further includes the following steps:

[0082] Periodically calculate the charge and discharge power of the energy storage element until the power of the energy storage element is lower than a preset fourth threshold.

[0083] Calculate the equivalent discharge power during the period when the power of the energy storage element drops from the third threshold to the fourth threshold;

[0084] Calculate the ratio of the equivalent discharge power to a preset reference discharge power;

[0085] When the ratio is greater than 1, calculate the square of the ratio as an adjustment coefficient, and adjust the third threshold to the product of a preset initial threshold and the adjustment coefficient;

[0086] When the ratio is not greater than 1, adjust the third threshold to the preset initial threshold, and the controller controls the forward charging circuit to work until the power of the energy storage element reaches the preset third threshold.

[0087] On the other hand, in another embodiment, the method for calculating the equivalent discharge power during the period when the power of the energy storage element drops from the third threshold to the fourth threshold includes the steps of:

[0088] Compare the charging and discharging power of the energy storage element read with a preset reference power, delete the charging and discharging power less than the preset reference power, and then calculate the average value of the remaining charging and discharging power as the equivalent discharge power.

[0089] The above-described embodiments are merely described in terms of the preferred embodiment modes of this specification, and do not limit the scope of this specification. Without departing from the design spirit of this specification, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of this specification shall fall within the protection scope determined by the claims of this specification.

Claims

1. A collaborative power quality governance system for a park, the park including a power supply ring network and a number of power supply branches, characterized in that, It includes a monitoring device, several energy storage converters, an active power filter, and a control device. The monitoring device monitors the voltage, frequency, and harmonics of the power supply ring network in the park. Several of the energy storage converters are respectively connected to several power supply branches. The energy storage converter includes a cabinet for accommodating devices therein, and a cabinet controller, an inverter, an energy storage battery, an energy storage element, a voltage stabilizing module, and a voltage transformation module provided in the cabinet. An input wiring box, a DC output wiring box, an AC output wiring box, and a communication device are installed on the cabinet. The energy storage battery and the energy storage element are connected through a bidirectional charging circuit. The energy storage element is connected to the input connection box by an adaptive charging circuit provided in the cabinet. The input wiring box is connected to an external power supply. The AC output wiring box is connected to a load. The AC output wiring box is connected to the energy storage element by an inverter provided in the cabinet. The DC output wiring box is connected to the energy storage battery through a voltage stabilizing module and a voltage transformation module provided in the cabinet. A cabinet monitoring device is provided in the cabinet, and the cabinet monitoring device monitors the temperature and humidity in the cabinet, and the working states of the energy storage battery and the energy storage element. The input end of the active power filter is powered by the inverter of an energy storage converter. When the voltage and frequency of the power supply ring network fluctuate beyond a preset threshold, the cabinet controller controls the energy storage converter to suppress the voltage and frequency fluctuations of the power supply ring network. The bidirectional charging circuit includes a forward charging circuit and a reverse charging circuit. The forward charging circuit uses the power of the energy storage battery to charge the energy storage element, and the reverse charging circuit uses the power of the energy storage element to charge the energy storage battery. The cabinet controller reads the power of the energy storage element. When the power of the energy storage element is higher than a preset first threshold, it controls the reverse charging circuit to work until the power of the energy storage element is lower than a preset second threshold. When the power of the energy storage element is lower than a preset fourth threshold, the cabinet controller controls the forward charging circuit to work until the power of the energy storage element is higher than a preset third threshold. The cabinet controller periodically calculates the charge and discharge power of the energy storage element until the power of the energy storage element is lower than a preset fourth threshold. It calculates the equivalent discharge power during the period when the power of the energy storage element drops from the third threshold to the fourth threshold. The cabinet controller calculates the ratio of the equivalent discharge power to a preset reference discharge power. When the ratio is greater than 1, it calculates the square of the ratio as an adjustment coefficient, and adjusts the third threshold to the product of a preset initial threshold and the adjustment coefficient. When the ratio is not greater than 1, it adjusts the third threshold to the preset initial threshold. The cabinet controller controls the forward charging circuit to work until the power of the energy storage element reaches the preset third threshold.

2. The system for collaborative governance of power quality in a park according to claim 1, wherein When the cabinet controller calculates the equivalent discharge power during the period when the power of the energy storage element drops from the third threshold to the fourth threshold, it performs the following steps: Compare the charge and discharge power of the energy storage element read with a preset reference power. After deleting the charge and discharge power less than the preset reference power, calculate the average value of the remaining charge and discharge power as the equivalent discharge power.

3. The cooperative power quality governance system for a park according to claim 1 or 2, characterized in that The adaptive charging circuit of the energy storage converter cabinet includes a DC charging circuit, an AC charging circuit and a detection module. The detection module detects the voltage and type of the external power supply. When the external power supply is DC power supply, the DC charging circuit charges the energy storage element, and when the external power supply is AC power supply, the AC charging circuit charges the energy storage element. The input junction box further includes a photovoltaic input module, a mains input module and a switching device. The photovoltaic input module is connected to an external photovoltaic panel, the mains input module is connected to a power supply ring network, and the adaptive charging circuit is connected to the photovoltaic input module and the mains input module through the switching device.

4. The cooperative power quality governance system for a park according to claim 1 or 2, characterized in that When the cabinet controller controls the energy storage converter cabinet to suppress the voltage and frequency fluctuations of the power supply ring network, the following steps are executed: Calculate the voltage deviation value and frequency deviation value of the power supply ring network, and generate an adjustment power according to the voltage deviation value and frequency deviation value; When the voltage or frequency of the power supply ring network is low, the cabinet controller controls the inverter to supply power to the power supply ring network with the adjustment power; When the voltage or frequency of the power supply ring network is high, the cabinet controller controls the adaptive charging circuit to charge the energy storage element with the adjustment power.

5. A collaborative power quality governance method for a park, characterized in that, Including steps: Including a monitoring device, a plurality of energy storage converter cabinets, an active power filter and a control device. The monitoring device monitors the voltage, frequency and harmonics of the power supply ring network in the park; Configure a plurality of the energy storage converter cabinets to be respectively connected to a plurality of power supply branches. The energy storage converter cabinet includes a cabinet body for accommodating devices therein, and a cabinet controller, an inverter, an energy storage battery, an energy storage element, a voltage stabilizing module and a voltage transformation module arranged in the cabinet body. An input junction box, a DC output junction box, an AC output junction box and a communication device are installed on the cabinet body; Connect the energy storage battery and the energy storage element through a bidirectional charging circuit. The energy storage element is connected to the input connection box by an adaptive charging circuit arranged in the cabinet body. The input junction box is connected to an external power supply, the AC output junction box is connected to a load, the AC output junction box is connected to the energy storage element by an inverter arranged in the cabinet body, the DC output junction box is connected to the energy storage battery through a voltage stabilizing module and a voltage transformation module arranged in the cabinet body, and a cabinet monitoring device is arranged in the cabinet body. The cabinet monitoring device monitors the temperature and humidity in the cabinet, and the working states of the energy storage battery and the energy storage element; Configure the input end of the active power filter to be powered by the inverter of an energy storage converter cabinet; When the voltage and frequency of the power supply ring network fluctuate beyond a preset threshold, the controller in the cabinet controls the energy storage converter cabinet to suppress the voltage and frequency fluctuations of the power supply ring network; The bidirectional charging circuit is set to include a forward charging circuit and a reverse charging circuit. The forward charging circuit uses the power of the energy storage battery to charge the energy storage element, and the reverse charging circuit uses the power of the energy storage element to charge the energy storage battery. Read the power of the energy storage element. When the power of the energy storage element is higher than a preset first threshold, control the reverse charging circuit to work until the power of the energy storage element is lower than a preset second threshold; When the power of the energy storage element is lower than a preset fourth threshold, the controller controls the forward charging circuit to work until the power of the energy storage element is higher than a preset third threshold; It further includes the following steps: Periodically calculate the charge-discharge power of the energy storage element until the power of the energy storage element is lower than a preset fourth threshold; Calculate the equivalent discharge power during the period when the power of the energy storage element drops from the third threshold to the fourth threshold; Calculate the ratio of the equivalent discharge power to a preset reference discharge power; When the ratio is greater than 1, calculate the square of the ratio as an adjustment coefficient, and adjust the third threshold to the product of a preset initial threshold and the adjustment coefficient; When the ratio is not greater than 1, adjust the third threshold to the preset initial threshold, and the controller controls the forward charging circuit to work until the power of the energy storage element reaches the preset third threshold.

6. A method for collaborative governance of power quality in a park according to claim 5, characterized in that, The method for calculating the equivalent discharge power during the period when the power of the energy storage element drops from the third threshold to the fourth threshold includes the steps of: Compare the charge-discharge power of the energy storage element read with a preset reference power, delete the charge-discharge power less than the preset reference power, and then calculate the average value of the remaining charge-discharge power as the equivalent discharge power.

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