Electric energy quality treatment device and system

Abstract

The invention discloses an electric energy quality treatment device and system, and relates to the photovoltaic field, a detection module is used for obtaining the voltage of the low-voltage side of a transformer in real time, and a network-forming converter is used for dynamically determining active and reactive power reference values for cooperative control according to the direction and degree of the voltage deviating from the normal range. Millisecond-level, stepless and smooth power regulation is realized through the power electronic converter, slow mechanical action is replaced, the battery module is controlled to absorb or release active power, the voltage of the transformer area is intelligently regulated and controlled, line loss is not additionally increased, the problems of slow response, limited regulation capability and incapability of effectively inhibiting voltage out-of-limit in the related technology are solved, and the system is suitable for large-scale popularization and application. The beneficial effects of rapidly stabilizing the voltage, reducing the system loss and improving the power supply reliability are achieved.

Description

Technical Field

[0001] This application relates to the photovoltaic field, and in particular to a power quality management device and system. Background Technology

[0002] The rapid growth of photovoltaic (PV) installed capacity has led to voltage fluctuations in distribution substations, such as sudden increases and decreases, placing higher demands on power quality management. Currently, voltage regulation in distribution substations mainly relies on two methods: one is adjusting transformer taps, but most transformers in distribution substations are not equipped with on-load tap changers, requiring manual operation with limited adjustment range, affecting power supply reliability; the other is using distributed generation inverters to absorb reactive power, but inverters have limited reactive power absorption capacity and increase line losses, failing to effectively solve the voltage exceeding limit problem.

[0003] Therefore, how to provide a solution to the above-mentioned technical problems is a problem that needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this application is to provide a power quality management device and system to at least solve the problems of slow response, limited regulation capability and inability to effectively suppress voltage over-limit in related technologies.

[0005] This application provides a power quality management device, including a battery module and a transformer, comprising:

[0006] The detection module is used to obtain the voltage detection value on the low-voltage side of the transformer;

[0007] A grid-type converter is installed between the battery module and the low-voltage side of the transformer. It is used to determine the corresponding active power reference value and / or reactive power reference value based on the direction and degree of deviation of the voltage detection value from the normal operating range. Using the active power reference value and / or reactive power reference value, it controls the battery module to absorb or release power so as to regulate the voltage on the low-voltage side of the transformer to the normal operating range.

[0008] Optionally, the grid-type converter includes:

[0009] The control module is used to determine the corresponding active power reference value and / or reactive power reference value based on the direction and degree of deviation of the voltage detection value from the normal operating range, and to generate and output a modulation signal using the active power reference value and / or reactive power reference value;

[0010] The power conversion module includes multiple switches, the control terminals of which are connected to the control module and are used to switch the operating state in response to the modulation signal so that the battery module absorbs or releases power; the operating state includes an on state or an off state.

[0011] Optionally, the control module is specifically used to determine an increased active power reference value and / or a decreased reactive power reference value when the voltage detection value is higher than the upper limit of the normal operating range, and to generate and output a modulation signal using the increased active power reference value and / or the decreased reactive power reference value.

[0012] Optionally, the control module is specifically used to determine a reduced active power reference value and / or an increased reactive power reference value when the voltage detection value is lower than the lower limit of the normal operating range, and to generate and output a modulation signal using the reduced active power reference value and / or the increased reactive power reference value.

[0013] Optionally, the control module is specifically used for:

[0014] Determine the corresponding active power reference value and / or reactive power reference value;

[0015] Using the aforementioned active power reference value and actual active power value, the voltage phase is obtained through a virtual synchronous generator algorithm;

[0016] Using the aforementioned reactive power reference value and actual reactive power value, the voltage amplitude is obtained through a virtual synchronous generator algorithm;

[0017] The reference voltage is obtained based on the voltage phase and the voltage amplitude;

[0018] The reference voltage and the sampled actual voltage value are input into the voltage loop to obtain the current reference value;

[0019] The current reference value and the sampled actual current value are input into the current loop to generate and output the modulation signal.

[0020] Optionally, the virtual inertia in the virtual synchronous generator algorithm satisfies a first relation, which is: ;

[0021] in, This represents the maximum sudden change in active power in the transformer substation area. The system's rated frequency, J represents the maximum frequency change value, and J is the virtual inertia.

[0022] Optionally, the power quality management device further includes a high-voltage control box, which comprises:

[0023] The battery management module is used to monitor the operating status of the battery module and output a protection signal when the battery module is in a protected state.

[0024] A protection module is used to perform protection actions in response to the protection signal.

[0025] Optionally, the power quality management device further includes a fire-fighting module for responding to a fire trigger signal and performing at least one level of fire extinguishing operation. The fire-fighting module includes at least one of a PACK-level fire extinguishing unit, a cluster-level fire extinguishing unit, and a cabinet-level water fire extinguishing unit.

[0026] Optionally, the power quality management device further includes a liquid cooling module, which uses an aqueous ethylene glycol solution as a refrigerant. The liquid cooling module includes a compressor refrigeration system, a heat exchanger, a control unit, a water system, and a circulating water pump. The compressor refrigeration system exchanges heat with the refrigerant through the heat exchanger.

[0027] The control unit is used to control the output temperature of the compressor refrigeration system and the speed of the circulating water pump based on the water temperature feedback signal and the pressure feedback signal.

[0028] This application also provides a power quality management system for a distribution substation, including a photovoltaic inverter and a power quality management device as described in any of the above.

[0029] This application acquires the low-voltage side voltage of the transformer in real time through a detection module, and the grid-type converter dynamically determines the reference values ​​of active and reactive power based on the direction and degree of voltage deviation from the normal range for coordinated control. The power electronic converter achieves millisecond-level, stepless, and smooth power regulation, replacing slow mechanical actions. By controlling the battery module to absorb or release active power, it intelligently regulates the voltage of the distribution area without adding extra line losses. This solves the problems of slow response, limited regulation capability, and inability to effectively suppress voltage over-limit in traditional methods, achieving the beneficial effects of rapid voltage stabilization, reduced system losses, and improved power supply reliability. Attached Figure Description

[0030] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A schematic diagram of the structure of the first power quality management device provided in this application;

[0032] Figure 2 A schematic diagram of the structure of the second type of power quality management device provided in this application;

[0033] Figure 3 A schematic diagram of the third type of power quality management device provided in this application;

[0034] Figure 4This is a schematic diagram of a power quality management system for a distribution substation provided in this application. Detailed Implementation

[0035] The core of this application is to provide a power quality management device and system to at least solve the problems of slow response, limited regulation capability and inability to effectively suppress voltage exceedance in related technologies.

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] Please refer to Figure 1 The present invention provides a power quality management device, comprising:

[0038] Detection module 1 is used to obtain the voltage detection value on the low-voltage side of the transformer;

[0039] The grid-type converter 2 is located between the battery module and the low-voltage side of the transformer. It is used to determine the corresponding active power reference value and / or reactive power reference value based on the direction and degree of deviation of the voltage detection value from the normal operating range. Using the active power reference value and / or reactive power reference value, it controls the battery module to absorb or release power so as to regulate the voltage on the low-voltage side of the transformer to the normal operating range.

[0040] In this embodiment, the battery module is an energy storage unit composed of multiple cells (such as 3.2V / 280Ah high-rate lithium iron phosphate cells) connected in series and parallel, used to provide a controllable, bidirectional power carrier; the transformer refers to the power transformer in the distribution substation that converts high voltage to low voltage on the user side, which is also the access point and the object of management of this device.

[0041] The detection module 1 includes at least a voltage sensor and signal conditioning circuitry, used to acquire the voltage detection value of the low-voltage side of the transformer in real time with high accuracy. The voltage detection value can include the detected three-phase voltage values ​​of the low-voltage side of the transformer. This voltage sensor can be installed on the busbar at the low-voltage side outgoing line of the transformer, i.e., the common connection point for power collection and distribution in the distribution substation. The voltage at this point can most directly reflect the voltage quality of the power supply from the transformer to the entire substation, avoiding the problem that the monitoring point located on a specific branch line cannot represent the overall voltage level of the substation. The detection module 1 acquires voltage signals through this voltage sensor, providing accurate feedback information for subsequent control decisions.

[0042] The grid-connected converter 2 is positioned between the battery module and the low-voltage side of the transformer to enable bidirectional energy flow between them. Based on the voltage detection value transmitted by the detection module 1, the grid-connected converter 2 determines whether the voltage deviates from the normal operating range. If it does, it determines the direction and extent of the deviation (e.g., whether it exceeds the upper limit or falls below the lower limit, and by how many volts). Then, through a built-in control algorithm, it determines the corresponding active power reference value and / or reactive power reference value.

[0043] The principle of controlling the power absorption or release of the battery module by modifying the active power reference value and reactive power reference value is understandable, based on the coupling relationship between active and reactive power in the AC grid and voltage amplitude and phase angle. The control algorithm of the grid-type converter 2, through decoupling control, can independently adjust the active and reactive power exchanged between it and the grid. Specifically: when the control algorithm increases the active power reference value, its purpose is to increase the active power absorbed from the grid; to achieve this, the algorithm adjusts the phase of the internally generated reference voltage signal, making it lead the phase of the grid voltage. Subsequently, this reference voltage signal is compared with the actual output voltage sample value of the converter, processed by a voltage and current dual closed-loop controller, and finally generates a corresponding pulse width modulation signal. This modulation signal drives the power semiconductor switching devices (such as SiC MOSFET modules) inside the converter to operate in the corresponding state, thereby controlling the flow of electrical energy from the AC side (grid) to the DC side (battery module), i.e., the battery module absorbs active power (charging). Conversely, when the active power reference value is reduced (or set to a negative value to indicate output), the control process is reversed, ultimately causing the battery module to release active power (discharge).

[0044] Correspondingly, when the control algorithm increases the reactive power reference value, its purpose is to supply inductive reactive power to the grid to support the voltage. The algorithm adjusts the amplitude of the reference voltage signal generated internally to make it higher than the amplitude of the grid voltage. Similarly, a modulation signal is generated through closed-loop control and drives the switching devices to supply inductive reactive power to the grid, thereby raising the voltage at the grid connection point. Conversely, when the reactive power reference value is decreased, the process is reversed, absorbing inductive reactive power from the grid, thereby lowering the voltage at the grid connection point.

[0045] In this embodiment, by detecting the real-time voltage monitoring at the point of common coupling by module 1, combined with the rapid calculation and response of the grid-type converter 2 based on the direction and degree of voltage deviation, millisecond-level precise control can be performed to address voltage over-limit issues, overcoming the shortcomings of slow and inflexible adjustment of traditional transformer taps. By simultaneously controlling the active power reference value and the reactive power reference value, this device can not only utilize the regulation effect of reactive power, but also absorb or release active power through the battery module, directly addressing the voltage over-limit problem caused by active power fluctuations of distributed power sources (such as photovoltaics) at its root. This solves the technical limitations of traditional methods that rely solely on the limited reactive power regulation capability of inverters and may increase line losses.

[0046] This device effectively suppresses voltage spikes and drops caused by fluctuations in photovoltaic output and load changes, stabilizing the voltage within the normal operating range and ensuring high-quality power supply for users. It also enhances the adaptability of the distribution area to high-proportion renewable energy integration. Furthermore, this device integrates energy storage and grid control, realizing a shift from traditional passive compensation to active support. It not only improves power quality but also provides the grid with a certain potential for inertia support.

[0047] Please refer to Figure 2 The power quality management device is based on the above embodiments:

[0048] In one exemplary embodiment, the grid-type converter 2 includes:

[0049] The control module is used to determine the corresponding active power reference value and / or reactive power reference value based on the direction and degree of deviation of the voltage detection value from the normal operating range, and to generate and output a modulation signal using the active power reference value and / or reactive power reference value;

[0050] The power conversion module includes multiple switches. The control terminals of the switches are connected to the control module and are used to switch the operating state in response to the modulation signal so that the battery module can absorb or release power. The operating state includes an on state or an off state.

[0051] This embodiment describes the internal structure of the grid-type converter 2, which includes a control module and a power conversion module. The control module typically consists of a digital signal processor and peripheral circuitry. Its function is to execute a voltage closed-loop control algorithm. First, it receives voltage detection values, determines active power reference values ​​and / or reactive power reference values, and generates and outputs modulation signals based on these reference values. These modulation signals can be pulse waveforms in formats such as SPWM or SVPWM. The power conversion module consists of multiple fully controlled power switching devices (such as SiC MOSFET modules) connected in a three-phase full-bridge topology. The control terminals (i.e., gate drive ports) of these switches are connected to the control module via a drive circuit to switch operating states in response to the modulation signals, i.e., high-speed switching between on and off states.

[0052] The control module and the power conversion module establish a control association through modulation signals. The modulation signals output by the control module determine the conduction timing and duty cycle of each switching device in the power conversion module, thereby controlling the direction of power conversion and transmission, and ultimately realizing the control of power absorption or release of the battery module.

[0053] The power conversion module can be implemented using various circuit topologies, such as two-level, three-level, or modular multi-level structures. This embodiment separates control from power execution; the digital control module ensures the accuracy and flexibility of control, while the standardized power module ensures high efficiency and reliability in power processing.

[0054] In an exemplary embodiment, the control module is specifically configured to determine an increased active power reference value and / or a decreased reactive power reference value when the voltage detection value is higher than the upper limit of the normal operating range, and generate and output a modulation signal using the increased active power reference value and / or the decreased reactive power reference value.

[0055] Specifically, when the voltage detection value is higher than the upper limit of the normal operating range, the control module is configured to perform a specific power reference value calculation, that is, to determine the increased active power reference value and / or the decreased reactive power reference value, that is, to increase the active power reference value by a certain value on the existing basis, or to decrease the reactive power reference value by a certain value on the existing basis.

[0056] It is understandable that the purpose of increasing the active power reference value is to reduce the net active power flowing from the grid side to the transformer by increasing the charging power of the battery module, thereby suppressing the voltage rise caused by excess active power (such as photovoltaic backfeeding). The purpose of decreasing the reactive power reference value is to control the converter to absorb inductive reactive power and use the voltage drop generated by the reactive current on the grid impedance to help reduce the voltage.

[0057] The control module generates and outputs a modulation signal using the increased active power reference value and / or decreased reactive power reference value, driving the power conversion module to perform the corresponding power conversion.

[0058] This embodiment provides two collaborative governance paths for addressing the problem of excessive voltage. In particular, by directly adjusting the active power, it can address the voltage over-limit challenge brought about by the increased penetration of distributed power sources at its root, resulting in a more fundamental and significant governance effect.

[0059] In an exemplary embodiment, the control module is specifically configured to determine a reduced active power reference value and / or an increased reactive power reference value when the voltage detection value is lower than the lower limit of the normal operating range, and generate and output a modulation signal using the reduced active power reference value and / or the increased reactive power reference value.

[0060] When the detected voltage value falls below the lower limit of the normal operating range, the control module is configured to perform operations corresponding to overvoltage conditions, namely, determining a reduced active power reference value and / or an increased reactive power reference value. The reduced active power reference value is typically represented by setting a negative value in the control logic. Its purpose is to instruct the battery module to release active power (discharge) to the grid, directly supporting the local grid voltage level by injecting active power. The purpose of increasing the reactive power reference value is to instruct the converter to send inductive reactive power to the grid, thereby increasing the voltage by compensating for line reactive power losses. The control module uses the reduced active power reference value and / or the increased reactive power reference value to generate and output a modulation signal, controlling the power conversion module to achieve the aforementioned power exchange.

[0061] This embodiment provides active active power injection and reactive power compensation as dual support for low voltage problems, and is especially suitable for peak load or insufficient photovoltaic output. It effectively solves the problem that traditional reactive power compensation devices are not effective in heavy active load scenarios.

[0062] In an exemplary embodiment, the control module is specifically used for:

[0063] Determine the corresponding active power reference value and / or reactive power reference value;

[0064] The voltage phase is obtained using the active power reference value and the actual active power value through a virtual synchronous generator algorithm;

[0065] The voltage amplitude is obtained using a virtual synchronous generator algorithm based on the reactive power reference value and the actual reactive power value.

[0066] The reference voltage is obtained based on the voltage phase and voltage amplitude;

[0067] The reference voltage and the sampled actual voltage value are input into the voltage loop to obtain the current reference value;

[0068] The current reference value and the sampled actual current value are input into the current loop to generate and output a modulated signal.

[0069] In this embodiment, the control module specifically executes the following process: First, it determines the corresponding active power reference value and / or reactive power reference value based on voltage management requirements. Then, it enters the core calculation of the virtual synchronous generator algorithm, which uses the active power reference value and the actual active power value to obtain the voltage phase. This process simulates the rotor motion equation of a synchronous generator, introducing virtual inertia and damping coefficients to give the system frequency inertia and damping characteristics. Simultaneously, using the reactive power reference value and the actual reactive power value, the voltage amplitude is obtained through the virtual synchronous generator algorithm, simulating the automatic excitation regulation function of a synchronous generator.

[0070] The control module obtains a reference voltage based on the voltage phase and amplitude; this reference voltage is an ideal sinusoidal signal. Then, it enters the inner loop control: it compares the reference voltage with the sampled actual voltage value, inputting the voltage loop to obtain the current reference value. This voltage loop ensures the output voltage quickly tracks the reference voltage. Finally, it compares the current reference value with the sampled actual current value, inputting the current loop to generate and output a modulation signal. This current loop, as the innermost loop, provides fast overcurrent protection and precise current control. The outer loop's VSG algorithm, along with the inner loop's voltage and current loops, are interconnected through the reference voltage and current reference values, forming a hierarchical control architecture. This embodiment, by simulating the operation mechanism of a synchronous generator, enables the power electronic converter to support grid frequency and voltage stability, significantly enhancing the stability and robustness of the distribution system under high-proportion renewable energy integration.

[0071] As an optional embodiment, the detection module 1 further includes a current sensor for acquiring the actual current value flowing through the filter inductor. and the actual current value on the low-voltage side of the transformer ,in, Used for current loop control to maintain rapid stabilization of the filter inductor current; and and Combined, it is used for power feedback calculations to ensure the system's adaptability to load changes.

[0072] The following is combined with Figure 2 The power loop, voltage loop, and current loop are explained.

[0073] The power loop is the outer loop of the entire control architecture, responsible for setting the active power based on the voltage management requirements of the power grid. ) and reactive power ( The reference value is used to compare the reference value with the actual value. , The VSG algorithm is used to simulate the motion equation of the synchronous generator rotor, introducing virtual inertia (J) and damping coefficient (D) to dynamically calculate the voltage phase. ) and amplitude ( This process endows the system with frequency inertia and damping characteristics, enabling it to respond to grid frequency fluctuations like a traditional synchronous generator. It also simulates automatic excitation regulation, providing a crucial reference voltage for subsequent control stages. , This control loop significantly enhances the system's frequency stability and dynamic response capability under high-proportion renewable energy access, providing strong inertia support for the power grid.

[0074] The voltage loop acts as an intermediate control layer, receiving the reference voltage generated by the power loop and the actual voltage value sampled after abc / dq transformation. , A proportional-integral (PI) controller can be used to calculate the voltage deviation and adjust the output to generate a current reference value. , This ensures that the output voltage can quickly and accurately track the reference voltage. This control loop guarantees the stability and rapid dynamic response of the output voltage, while also providing the current loop with a precise current control target, thus improving overall control accuracy.

[0075] The current loop is the innermost control loop and directly relates to the converter's current output control. It receives the current reference value generated by the voltage loop and the actual current value sampled after ABC / DQ transformation. , Similarly, using a PI controller, the current loop monitors current deviation in real time, quickly adjusts and outputs a modulation signal (such as an SVPWM signal) to achieve precise control of the inverter's switching action. The current loop also provides a fast overcurrent protection mechanism to prevent the inverter from being damaged by current surges, and ensures the accuracy of the current output, thereby guaranteeing the power quality of the grid, especially maintaining stable system operation during load changes or grid disturbances.

[0076] In an exemplary embodiment, the virtual inertia in the virtual synchronous generator algorithm satisfies a first relation, which is: ;

[0077] in, This represents the maximum sudden change in active power in the transformer substation area. The system's rated frequency, J represents the maximum frequency change value, and J is the virtual inertia.

[0078] In this embodiment, This represents the maximum sudden change in active power in the transformer area, indicating the most severe power disturbance the system may face. The rated frequency of the system is the target frequency for normal system operation.

[0079] This first relation defines the lower bound of the virtual inertia J, with the aim of ensuring that when a preset maximum power disturbance occurs in the distribution area... At that time, the virtual inertia provided by the VSG control is sufficient to limit the frequency variation of the system to an allowable range. Within the specified range. There is a clear correlation between the parameters. The design boundary conditions were defined. and The stability requirements are jointly defined, and J is the system parameter that needs to be configured to meet these stability requirements. The specific value of the virtual inertia can be obtained through system stability analysis and calculated, and then set in the control module program. This embodiment provides clear and quantitative design guidelines for the engineering tuning of the key parameter, virtual inertia, ensuring that the VSG control can still play its expected stable support role under the worst disturbances, and improving the predictability of the device's performance and its applicability in power systems.

[0080] In one exemplary embodiment, reference is made to Figure 3 The power quality management device also includes a high-voltage control box 3, which includes:

[0081] The battery management module is used to monitor the operating status of the battery module and output a protection signal when the battery module is in a protected state.

[0082] The protection module is used to perform protection actions in response to protection signals.

[0083] In this embodiment, the power quality management device also includes a high-voltage control box 3 to construct a safety management system for the battery system. The high-voltage control box 3 is an integrated electrical control and protection unit, primarily comprising a battery management module and a protection module. The battery management module (BMS) typically consists of a main control unit, monitoring chips, and communication circuits. Its purpose is to monitor and manage the operating status of the battery module, including real-time acquisition of parameters such as the voltage and temperature of each individual battery cell, and the total voltage and current of the battery cluster. Its core function is to determine, based on this monitoring data and through an internally set safety algorithm, whether the battery module is in a state requiring protection, such as when any parameter exceeds limits (overvoltage, undervoltage, overtemperature, etc.). Once a state requiring protection is determined, the BMS outputs a protection signal. The protection module typically consists of a main circuit contactor, fuses, and their drive circuits. Its function is to quickly respond to protection signals and execute protection actions, such as cutting off the main circuit to achieve electrical isolation. The battery management module and the protection module form a monitoring-decision-execution relationship, jointly achieving secondary safety protection for the battery system. The specific implementation of the high-voltage control box 3 can be designed with reference to relevant electrical standards. This embodiment, through the professional high-voltage control box 3 design, provides comprehensive battery status monitoring and rapid fault isolation capabilities for energy storage power quality management devices, greatly improving the system's safety level and operational reliability, and is a necessary guarantee for the long-term stable operation of the device.

[0084] In one exemplary embodiment, reference is made to Figure 3 The power quality management device also includes a fire-fighting module 4, which is used to respond to a fire trigger signal and perform at least one level of fire extinguishing operation. The fire-fighting module 4 includes at least one of a PACK-level fire extinguishing unit, a cluster-level fire extinguishing unit, and a cabinet-level water fire extinguishing unit.

[0085] In this embodiment, a fire suppression module 4 is integrated into the power quality management device to address extreme safety risks such as battery thermal runaway. This fire suppression module 4 is a multi-level, multi-method integrated safety protection system. Its function is to respond to fire trigger signals and execute at least one level of fire suppression operation. Specifically, the fire suppression module 4 may include at least one of a PACK-level fire suppression unit, a cluster-level fire suppression unit, and a cabinet-level water fire suppression unit.

[0086] PACK-level fire suppression units deploy perfluorohexanone (PFH) extinguishing agent and its release device (such as a suppression tube) inside or near each individual battery pack (i.e., a battery pack composed of multiple cells). Their goal is to extinguish initial fires within a single pack caused by thermal runaway of individual cells, preventing the fire from spreading to the entire battery cluster. Cluster-level fire suppression units, at the level of battery clusters (composed of multiple battery packs connected in series or parallel), establish an extinguishing agent distribution and spraying system covering the entire cluster area. When a PACK-level fire suppression system fails to control the fire, or when the fire begins to spread within the cluster, the cluster-level system activates, flooding the entire battery cluster area to prevent the fire from spreading to other equipment within the cabinet.

[0087] The cabinet-level water fire suppression unit is equipped with a traditional water fire suppression system throughout the entire energy storage cabinet level. When both primary and secondary chemical fire suppression systems fail and the fire develops into a large-scale open flame, the cabinet-level water fire suppression system is activated.

[0088] Through PACK-level and cluster-level perfluorohexanone systems, a response time within seconds is achieved in the early stages of a fire. The extinguishing agent acts directly on the fire source, enabling precise fire suppression and minimizing losses. The three-tiered fire protection system forms a defense-in-depth system, with each level acting as a fire barrier to ensure the fire is contained within the smallest possible area (PACK → Cluster → Cabinet). It incorporates both chemical (perfluorohexanone) and physical (water) extinguishing methods, along with triple protection from the PACK level down to the cabinet level. Even if one level of the system fails, the next higher level can still provide protection, significantly improving the reliability of the entire fire protection system.

[0089] In one exemplary embodiment, please refer to Figure 3 The power quality management device also includes a liquid cooling module 5, which uses ethylene glycol aqueous solution as a refrigerant. The liquid cooling module 5 includes a compressor refrigeration system, a heat exchanger, a control unit, a water system and a circulating water pump. The compressor refrigeration system exchanges heat with the refrigerant through the heat exchanger.

[0090] The control unit is used to control the output temperature of the compressor refrigeration system and the speed of the circulating water pump based on water temperature feedback signals and pressure feedback signals.

[0091] In this embodiment, a liquid cooling module 5 is further integrated to solve the heat dissipation problem during high-power charging and discharging of the battery, ensuring that the battery operates within its optimal temperature range. The liquid cooling module 5 uses an aqueous ethylene glycol solution as the refrigerant. This module mainly includes a compressor refrigeration system, a heat exchanger, a control unit, a water system, and a circulating water pump. The compressor refrigeration system acts as the cold source, exchanging heat with the refrigerant through the heat exchanger, thereby cooling the refrigerant. Driven by the circulating water pump, the cooled refrigerant flows through the cooling channels inside the battery module via the water system, absorbing the heat generated by the battery. The control unit, as the system's regulating center, controls the output temperature of the compressor refrigeration system and the rotational speed of the circulating water pump based on water temperature and pressure feedback signals, thereby achieving precise control of the battery temperature. All components, through the flow of the refrigerant, form a complete closed-loop thermal management system. The specific implementation of the liquid cooling system can be achieved by selecting compressors and pumps of different power ratings according to heat dissipation requirements. Compared to air-cooled systems, liquid cooling offers higher heat dissipation efficiency, more uniform temperature distribution, and lower operating noise. It ensures that the battery operates within its optimal temperature range, thereby protecting its performance, extending its cycle life, and supporting the device's continuous participation in high-power power quality management.

[0092] Please refer to Figure 4 This application also provides a power quality management system for a distribution substation, including a photovoltaic inverter and a power quality management device as described in any of the embodiments above.

[0093] In this embodiment, the power quality management device is connected to the low-voltage side of the transformer via a JP cabinet. This connection method allows for an integrated design of the system. For existing distribution areas, no large-scale modifications to the existing power grid structure are required; the power quality management device can be directly installed below the transformer in the distribution area and connected directly to the system via the JP cabinet, demonstrating good compatibility. When the photovoltaic power generation in the distribution area exceeds the local load consumption, causing active power to be reversed to the transformer and resulting in a voltage rise exceeding the limit, the system activates the power quality management device, controlling its battery module energy storage to absorb the excess photovoltaic power generation locally, thereby suppressing the voltage rise. When the photovoltaic power generation decreases while the electrical load increases, causing a voltage drop, the management device controls the battery module to discharge, providing active power support to the grid to meet load demand and raise the voltage to the normal range.

[0094] This embodiment provides a complete, efficient, and easy-to-deploy comprehensive power quality management solution for distribution transformer areas. Through the synergy of photovoltaic inverters and grid-based management devices, not only is the full utilization of clean energy achieved, but the power quality problems it brings are also proactively resolved. In particular, the integrated design of JP cabinet access greatly facilitates the transformation and upgrading of existing transformer areas, and has the advantages of quick deployment and strong compatibility, realizing dynamic management of transformer area voltage and high-quality power supply.

[0095] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0096] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power quality management device, comprising a battery module and a transformer, characterized in that, include: The detection module is used to obtain the voltage detection value on the low-voltage side of the transformer; A grid-type converter is installed between the battery module and the low-voltage side of the transformer. It is used to determine the corresponding active power reference value and / or reactive power reference value based on the direction and degree of deviation of the voltage detection value from the normal operating range. Using the active power reference value and / or reactive power reference value, it controls the battery module to absorb or release power so as to regulate the voltage on the low-voltage side of the transformer to the normal operating range.

2. The power quality management device according to claim 1, characterized in that, The grid-type converter includes: The control module is used to determine the corresponding active power reference value and / or reactive power reference value based on the direction and degree of deviation of the voltage detection value from the normal operating range, and to generate and output a modulation signal using the active power reference value and / or reactive power reference value; The power conversion module includes multiple switches, the control terminals of which are connected to the control module and are used to switch the operating state in response to the modulation signal so that the battery module absorbs or releases power; the operating state includes an on state or an off state.

3. The power quality management device according to claim 2, characterized in that, The control module is specifically used to determine an increased active power reference value and / or a decreased reactive power reference value when the voltage detection value is higher than the upper limit of the normal operating range, and to generate and output a modulation signal using the increased active power reference value and / or the decreased reactive power reference value.

4. The power quality management device according to claim 3, characterized in that, The control module is specifically used to determine a reduced active power reference value and / or an increased reactive power reference value when the voltage detection value is lower than the lower limit of the normal operating range, and to generate and output a modulation signal using the reduced active power reference value and / or the increased reactive power reference value.

5. The power quality management device according to claim 2, characterized in that, The control module is specifically used for: Determine the corresponding active power reference value and / or reactive power reference value; Using the aforementioned active power reference value and actual active power value, the voltage phase is obtained through a virtual synchronous generator algorithm; Using the aforementioned reactive power reference value and actual reactive power value, the voltage amplitude is obtained through a virtual synchronous generator algorithm; The reference voltage is obtained based on the voltage phase and the voltage amplitude; The reference voltage and the sampled actual voltage value are input into the voltage loop to obtain the current reference value; The current reference value and the sampled actual current value are input into the current loop to generate and output the modulation signal.

6. The power quality management device according to claim 5, characterized in that, The virtual inertia in the virtual synchronous generator algorithm satisfies a first relation, which is: ; in, This represents the maximum sudden change in active power in the transformer substation area. The system's rated frequency, J represents the maximum frequency change value, and J is the virtual inertia.

7. The power quality management device according to claim 1, characterized in that, The power quality management device further includes a high-voltage control box, which comprises: The battery management module is used to monitor the operating status of the battery module and output a protection signal when the battery module is in a protected state. A protection module is used to perform protection actions in response to the protection signal.

8. The power quality management device according to any one of claims 1-7, characterized in that, The power quality management device also includes a fire-fighting module for responding to a fire trigger signal and performing at least one level of fire extinguishing operation. The fire-fighting module includes at least one of a PACK-level fire extinguishing unit, a cluster-level fire extinguishing unit, and a cabinet-level water fire extinguishing unit.

9. The power quality management device according to claim 8, characterized in that, The power quality management device also includes a liquid cooling module, which uses an aqueous ethylene glycol solution as a refrigerant. The liquid cooling module includes a compressor refrigeration system, a heat exchanger, a control unit, a water system, and a circulating water pump. The compressor refrigeration system exchanges heat with the refrigerant through the heat exchanger. The control unit is used to control the output temperature of the compressor refrigeration system and the speed of the circulating water pump based on the water temperature feedback signal and the pressure feedback signal.

10. A power quality management system for a distribution substation, characterized in that, It includes photovoltaic inverters and power quality management devices as described in any one of claims 1-9.

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