A light storage system for governing three-phase imbalance

Abstract

This utility model discloses a photovoltaic-storage system for addressing three-phase imbalance, comprising a photovoltaic-storage unit assembly, circuit breakers QF8 and QF5, an electricity meter, circuit breaker QF1, a three-phase imbalance transformer, circuit breakers QF7 and QF6. The positive terminal of the photovoltaic-storage unit assembly is connected to the three-phase imbalance transformer via circuit breakers QF8, QF5, the electricity meter, and QF1. The negative terminal of the photovoltaic-storage unit assembly is connected to the three-phase imbalance transformer via circuit breakers QF8, QF5, the electricity meter, and QF1, forming a circuit for grid-connected charging and discharging. This invention, through the combination of the photovoltaic-storage system and a specific control algorithm, can detect the power of each phase in real time and dynamically adjust the charging and discharging state of the integrated photovoltaic-storage unit, accurately balancing the three-phase power, significantly improving power quality, and effectively solving the voltage quality reduction problem caused by three-phase imbalance in rural transformer areas.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic energy storage, and in particular to a photovoltaic energy storage system for addressing three-phase imbalance. Background Technology

[0002] In rural power distribution systems, most use a three-phase four-wire power supply. However, due to insufficient awareness of standardized procedures among staff, two phases (e.g., A and B) are randomly selected for connection to the user end for convenience. If phases A and B in this distribution area have high-power loads and many loads, the current in phases A and B will be greater than that in phase C, and the voltage in phase C will be higher than that in phases A and B. As the load in the distribution area continues to expand and become more disordered, it may generate even larger three-phase unbalanced currents, leading to a decrease in voltage quality at the user end. To address the problems of "heavy overload, low voltage, and three-phase imbalance" in rural power supply systems...

[0003] Therefore, in order to solve the above problems, how to design a photovoltaic energy storage system for addressing three-phase imbalance is a technical problem that the industry urgently needs to solve. Utility Model Content

[0004] The purpose of this invention is to provide a photovoltaic energy storage system for addressing three-phase imbalance, thereby solving the problems of heavy overload, low voltage, and three-phase imbalance mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A photovoltaic-storage system for mitigating three-phase imbalance includes photovoltaic-storage unit components, circuit breakers QF8 and QF5, an electricity meter, circuit breaker QF1, a three-phase imbalance transformer, circuit breaker QF7, and circuit breaker QF6.

[0007] The positive terminal of the photovoltaic energy storage unit is connected to the three-phase unbalanced transformer via circuit breaker QF8, circuit breaker QF5, electricity meter, circuit breaker QF1, and the negative terminal of the photovoltaic energy storage unit is connected to the three-phase unbalanced transformer via circuit breaker QF8, circuit breaker QF5, electricity meter, circuit breaker QF1, forming a circuit for grid-connected charging and discharging.

[0008] The positive terminal of the photovoltaic energy storage unit is connected to the three-phase unbalanced transformer via circuit breaker QF7, circuit breaker QF6, electricity meter, circuit breaker QF1, and the negative terminal of the photovoltaic energy storage unit is connected to the three-phase unbalanced transformer via circuit breaker QF6, electricity meter, circuit breaker QF1, forming a circuit for the off-grid discharge port.

[0009] Preferably, the photovoltaic-storage unit assembly includes photovoltaic-storage unit one, photovoltaic-storage unit two, and photovoltaic-storage unit three, and they have the same layout and composition. Photovoltaic-storage unit one includes port a and port b, and the three-phase unbalanced transformer includes terminal A, terminal B, terminal C, and neutral terminal N.

[0010] The positive terminal of port a of the photovoltaic energy storage unit is connected to terminal A of the three-phase unbalanced transformer in sequence through circuit breaker QF8, circuit breaker QF5, meter, and circuit breaker QF1. The negative terminal of port a of the photovoltaic energy storage unit is connected to terminal N of the neutral line of the three-phase unbalanced transformer in sequence through circuit breaker QF8, circuit breaker QF5, meter, and circuit breaker QF1, thus forming the first phase control circuit.

[0011] The positive terminal of port a of the second photovoltaic energy storage unit is connected to terminal B of the three-phase unbalanced transformer in sequence through circuit breaker QF8, circuit breaker QF5, meter, and circuit breaker QF1. The negative terminal of port a of the second photovoltaic energy storage unit is connected to terminal N of the neutral line of the three-phase unbalanced transformer in sequence through circuit breaker QF8, circuit breaker QF5, meter, and circuit breaker QF1, thus forming the second phase control circuit.

[0012] The positive terminal of the photovoltaic energy storage unit's third a port is connected to the C terminal of the three-phase unbalanced transformer via circuit breaker QF8, circuit breaker QF5, electricity meter, and circuit breaker QF1 in sequence. The negative terminal of the photovoltaic energy storage unit's third a port is connected to the neutral N terminal of the three-phase unbalanced transformer via circuit breaker QF8, circuit breaker QF5, electricity meter, and circuit breaker QF1 in sequence, forming the third phase control circuit.

[0013] The positive terminal of port b of the photovoltaic energy storage unit is connected to terminal A of the three-phase unbalanced transformer in sequence through circuit breaker QF7, circuit breaker QF6, meter, and circuit breaker QF1. The negative terminal of port b of the photovoltaic energy storage unit is connected to terminal N of the neutral line of the three-phase unbalanced transformer in sequence through circuit breaker QF7, circuit breaker QF6, meter, and circuit breaker QF1, thus forming a fourth-phase control circuit.

[0014] The positive terminal of port 2b of the photovoltaic energy storage unit is connected to terminal B of the three-phase unbalanced transformer in sequence through circuit breaker QF7, circuit breaker QF6, meter, and circuit breaker QF1. The negative terminal of port 2b of the photovoltaic energy storage unit is connected to terminal N of the neutral line of the three-phase unbalanced transformer in sequence through circuit breaker QF7, circuit breaker QF6, meter, and circuit breaker QF1, thus forming the fifth phase control circuit.

[0015] The positive terminal of the three b-port of the photovoltaic energy storage unit is connected to the C-terminal of the three-phase unbalanced transformer in sequence through circuit breakers QF7, QF6, the meter, and QF1. The negative terminal of the three b-port of the photovoltaic energy storage unit is connected to the neutral N-terminal of the three-phase unbalanced transformer in sequence through circuit breakers QF7, QF6, the meter, and QF1, thus forming the sixth phase control circuit.

[0016] Preferably, the photovoltaic-storage unit includes several sets of photovoltaic modules PV, circuit breakers QF9, several sets of batteries BAT, a high-voltage box, circuit breakers QF10, and a unidirectional photovoltaic-storage integrated unit. The photovoltaic modules PV are connected to the unidirectional photovoltaic-storage integrated unit #1 through circuit breakers QF9, the batteries BAT are connected to the unidirectional photovoltaic-storage integrated unit #1 through circuit breakers QF10, and the unidirectional photovoltaic-storage integrated unit #1 is connected to circuit breakers QF7 and QF8 respectively.

[0017] Preferably, in the third-phase management circuit and the sixth-phase management circuit, the input terminal of the circuit breaker QF4 is connected in parallel to the positive circuit node between the circuit breaker QF5 and the meter, the output terminal of the circuit breaker QF4 is connected to the power supply of the equipment in the cabinet, and the output terminal of the power supply of the equipment in the cabinet is connected to the negative circuit node between the circuit breaker QF5 and the meter in the first-phase management circuit and the fourth-phase management circuit.

[0018] Preferably, in the second phase control circuit and the fifth phase control circuit, the input terminal of the circuit breaker QF3 is connected in parallel to the positive circuit node between the circuit breaker QF5 and the meter, the output terminal of the circuit breaker QF3 is connected to the power supply of the equipment in the cabinet, and the output terminal of the power supply of the equipment in the cabinet is connected to the negative circuit node between the circuit breaker QF5 and the meter in the second phase control circuit and the fifth phase control circuit.

[0019] Preferably, in the first phase control circuit and the third phase control circuit, the input terminal of circuit breaker QF2 is connected in parallel to the positive circuit node between circuit breaker QF5 and the meter. The output terminal of circuit breaker QF2 is connected to an uninterruptible power supply (UPS). The output terminal of the UPS is connected to an energy management system (EMS). The output terminal of the EMS is connected to the UPS. The UPS is connected to the negative circuit node between circuit breaker QF5 and the meter in the first phase control circuit and the third phase control circuit through circuit breaker QF2.

[0020] Preferably, the fire-fighting equipment is connected in parallel to the positive circuit node of the energy management system (EMS) and the uninterruptible power supply (UPS). The output terminal of the fire-fighting equipment is connected to the uninterruptible power supply (UPS). The uninterruptible power supply (UPS) is connected to the negative circuit node between the circuit breaker QF5 and the electricity meter in the first phase management circuit and the third phase management circuit through the circuit breaker QF2.

[0021] Preferably, the positive circuit between the circuit breaker QF1 and the three-phase unbalanced transformer is connected in parallel to the input terminal of the load electrical equipment, and the output terminal of the load electrical equipment is connected to the negative circuit between the circuit breaker QF1 and the three-phase unbalanced transformer.

[0022] Preferably, the energy management system (EMS) detects the circuitry of the load-consuming electrical equipment by connecting to a load power detection system.

[0023] The beneficial effects of this utility model are:

[0024] 1. In existing technologies, equipment such as line voltage regulation, phase switching, and reactive power compensation devices cannot fundamentally solve the three-phase imbalance problem. However, this invention, through the combination of a photovoltaic energy storage system and a specific control algorithm, can detect the power of each phase in real time and dynamically adjust the charging and discharging state of the photovoltaic energy storage integrated machine, accurately balance the three-phase power, significantly improve power quality, and effectively solve the problem of voltage quality reduction caused by "three-phase imbalance" in rural transformer areas.

[0025] 2. Existing solutions often require upgrading and modifying power supply lines, which is costly and complex to construct. This invention mainly constructs the system by adding photovoltaic modules, energy storage batteries, and integrated photovoltaic-energy storage units, without requiring large-scale modifications to the original lines, thus reducing implementation difficulty and cost.

[0026] 3. Existing equipment has limited functionality, only addressing single issues such as three-phase imbalance or voltage regulation. The photovoltaic-storage system of this invention integrates three major functions: peak shaving and valley filling, backup power supply, and three-phase imbalance mitigation in power distribution areas. It flexibly switches modes in different scenarios, significantly improving the overall utilization rate of the equipment.

[0027] 4. On the one hand, the elimination of the need for line modifications reduces initial investment; on the other hand, photovoltaic modules can convert solar energy into electrical energy, reducing dependence on grid power. Energy storage batteries can store electricity during off-peak hours and discharge during peak hours (peak shaving and valley filling), reducing electricity costs and demonstrating significant economic benefits in the long run.

[0028] 5. The system is equipped with an EMS (Energy Management System), which can monitor equipment operating status and energy flow in real time. Combined with protection devices such as circuit breakers and UPS, it ensures that core equipment can still be powered in case of emergencies (such as power outages), improving the system's stability and reliability. At the same time, the configuration of fire-fighting equipment also reduces safety risks and ensures the safe operation of the system. Attached Figure Description

[0029] Figure 1 This is a system diagram of an embodiment of the present utility model;

[0030] Figure 2 This utility model Figure 1 Enlarged structural diagram at point A in the diagram;

[0031] Figure 3 This utility model Figure 1 A magnified structural diagram at point B in the diagram. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0033] See Figures 1-3 This utility model provides a photovoltaic-storage system for addressing three-phase imbalance, comprising a photovoltaic-storage unit assembly, circuit breakers QF8 and QF5, an electricity meter, circuit breaker QF1, a three-phase imbalance transformer, circuit breaker QF7, and circuit breaker QF6.

[0034] The positive terminal of the photovoltaic energy storage unit is connected to the three-phase unbalanced transformer via circuit breaker QF8, circuit breaker QF5, electricity meter, circuit breaker QF1, and the negative terminal of the photovoltaic energy storage unit is connected to the three-phase unbalanced transformer via circuit breaker QF8, circuit breaker QF5, electricity meter, circuit breaker QF1, forming a circuit for grid-connected charging and discharging.

[0035] The positive terminal of the photovoltaic energy storage unit is connected to the three-phase unbalanced transformer via circuit breaker QF7, circuit breaker QF6, electricity meter, circuit breaker QF1, and the negative terminal of the photovoltaic energy storage unit is connected to the three-phase unbalanced transformer via circuit breaker QF6, electricity meter, circuit breaker QF1, forming a circuit for the off-grid discharge port.

[0036] Circuit breakers QF8, QF5, QF1, QF7, and QF6 control the connection and disconnection of the circuits, while also protecting them. The photovoltaic energy storage unit generates electricity, the electricity meter measures the energy, and the three-phase unbalanced transformer primarily balances the three-phase load, reduces losses, and protects equipment in the power system.

[0037] The specific functions of a three-phase unbalanced transformer are as follows:

[0038] Three-phase load balancing automatically adjusts load distribution by monitoring the three-phase imbalance in the power grid in real time, ensuring balanced current in each phase and preventing overheating and equipment damage caused by uneven load distribution.

[0039] Reduce losses, decrease transformer iron and copper losses, optimize power transmission efficiency, and reduce line losses and additional heat generation caused by neutral current.

[0040] Protect equipment safety, prevent damage to electrical equipment due to voltage fluctuations (such as overvoltage or undervoltage), and prevent excessive neutral current from causing safety hazards in the power distribution system.

[0041] To improve system stability, dynamic load distribution can be adjusted to enhance the power grid's immunity and reduce the impact of voltage fluctuations caused by imbalances on sensitive equipment.

[0042] Specifically, the photovoltaic-storage unit assembly includes photovoltaic-storage unit one, photovoltaic-storage unit two, and photovoltaic-storage unit three, with identical layout and composition. Photovoltaic-storage unit one includes port a and port b. The three-phase unbalanced transformer includes connection terminal A, connection terminal B, connection terminal C, and neutral terminal N.

[0043] The positive terminal of port a of the photovoltaic energy storage unit is connected to terminal A of the three-phase unbalanced transformer in sequence through circuit breaker QF8, circuit breaker QF5, meter, and circuit breaker QF1. The negative terminal of port a of the photovoltaic energy storage unit is connected to terminal N of the neutral line of the three-phase unbalanced transformer in sequence through circuit breaker QF8, circuit breaker QF5, meter, and circuit breaker QF1, thus forming the first phase control circuit.

[0044] The positive terminal of port a of the second photovoltaic energy storage unit is connected to terminal B of the three-phase unbalanced transformer in sequence through circuit breaker QF8, circuit breaker QF5, meter, and circuit breaker QF1. The negative terminal of port a of the second photovoltaic energy storage unit is connected to terminal N of the neutral line of the three-phase unbalanced transformer in sequence through circuit breaker QF8, circuit breaker QF5, meter, and circuit breaker QF1, thus forming the second phase control circuit.

[0045] The positive terminal of the photovoltaic energy storage unit's third a port is connected to the C terminal of the three-phase unbalanced transformer via circuit breaker QF8, circuit breaker QF5, electricity meter, and circuit breaker QF1 in sequence. The negative terminal of the photovoltaic energy storage unit's third a port is connected to the neutral N terminal of the three-phase unbalanced transformer via circuit breaker QF8, circuit breaker QF5, electricity meter, and circuit breaker QF1 in sequence, forming the third phase control circuit.

[0046] The positive terminal of port b of the photovoltaic energy storage unit is connected to terminal A of the three-phase unbalanced transformer in sequence through circuit breaker QF7, circuit breaker QF6, meter, and circuit breaker QF1. The negative terminal of port b of the photovoltaic energy storage unit is connected to terminal N of the neutral line of the three-phase unbalanced transformer in sequence through circuit breaker QF7, circuit breaker QF6, meter, and circuit breaker QF1, thus forming a fourth-phase control circuit.

[0047] The positive terminal of port 2b of the photovoltaic energy storage unit is connected to terminal B of the three-phase unbalanced transformer in sequence through circuit breaker QF7, circuit breaker QF6, meter, and circuit breaker QF1. The negative terminal of port 2b of the photovoltaic energy storage unit is connected to terminal N of the neutral line of the three-phase unbalanced transformer in sequence through circuit breaker QF7, circuit breaker QF6, meter, and circuit breaker QF1, thus forming the fifth phase control circuit.

[0048] The positive terminal of the three b-port of the photovoltaic energy storage unit is connected to the C-terminal of the three-phase unbalanced transformer in sequence through circuit breakers QF7, QF6, the meter, and QF1. The negative terminal of the three b-port of the photovoltaic energy storage unit is connected to the neutral N-terminal of the three-phase unbalanced transformer in sequence through circuit breakers QF7, QF6, the meter, and QF1, thus forming the sixth phase control circuit.

[0049] Specifically, the photovoltaic-storage unit includes several sets of photovoltaic modules (PV), circuit breakers (QF9), several sets of batteries (BAT), a high-voltage box, circuit breakers (QF10), and a unidirectional photovoltaic-storage integrated unit. The photovoltaic modules (PV) are connected to the unidirectional photovoltaic-storage integrated unit #1 through circuit breakers (QF9), and the batteries (BAT) are connected to the unidirectional photovoltaic-storage integrated unit #1 through circuit breakers (QF10). The unidirectional photovoltaic-storage integrated unit #1 is connected to circuit breakers (QF7 and QF8) respectively.

[0050] Among them, circuit breakers QF9 and QF10 serve to protect the circuit.

[0051] Specifically, in the third-phase management circuit and the sixth-phase management circuit, the input terminal of the circuit breaker QF4 is connected in parallel to the positive circuit node between the circuit breaker QF5 and the meter, the output terminal of the circuit breaker QF4 is connected to the power supply of the equipment in the cabinet, and the output terminal of the power supply of the equipment in the cabinet is connected to the negative circuit node between the circuit breaker QF5 and the meter in the first-phase management circuit and the fourth-phase management circuit.

[0052] Among them, circuit breaker QF4 plays the role of protecting the circuit.

[0053] Specifically, in the second phase control circuit and the fifth phase control circuit, the positive circuit node between the circuit breaker QF5 and the meter is connected in parallel to the input terminal of the circuit breaker QF3, the output terminal of the circuit breaker QF3 is connected to the power supply of the equipment in the cabinet, and the output terminal of the power supply of the equipment in the cabinet is connected to the negative circuit node between the circuit breaker QF5 and the meter in the second phase control circuit and the fifth phase control circuit.

[0054] Among them, circuit breaker QF3 plays a role in protecting the circuit.

[0055] Specifically, in the first phase management circuit and the third phase management circuit, the input terminal of circuit breaker QF2 is connected in parallel to the positive circuit node between circuit breaker QF5 and the meter. The output terminal of circuit breaker QF2 is connected to an uninterruptible power supply (UPS). The output terminal of the UPS is connected to an energy management system (EMS). The output terminal of the EMS is connected to the UPS. The UPS is connected to the negative circuit node between circuit breaker QF5 and the meter in the first phase management circuit and the third phase management circuit through circuit breaker QF2.

[0056] Circuit breaker QF2 serves to protect the circuit. The uninterruptible power supply (UPS) provides power to critical equipment such as the BMS, EMS, fire protection systems, and other essential equipment when the main equipment is without power. The energy management system (EMS) is an intelligent system integrating hardware and software, used to monitor, control, and optimize energy flow and consumption within the energy system. Based on data acquisition, analysis, and decision support technologies, it can monitor the operating status of energy equipment, energy consumption, and environmental conditions in real time, thereby achieving efficient energy management and optimization.

[0057] Specifically, the fire-fighting equipment is connected in parallel to the positive circuit node of the energy management system (EMS) and the uninterruptible power supply (UPS). The output terminal of the fire-fighting equipment is connected to the uninterruptible power supply (UPS). The uninterruptible power supply (UPS) is connected to the negative circuit node between the circuit breaker (QF5) and the electricity meter in the first phase management circuit and the third phase management circuit through the circuit breaker (QF2).

[0058] Specifically, the positive circuit between the circuit breaker QF1 and the three-phase unbalanced transformer is connected in parallel to the input terminal of the load electrical equipment, and the output terminal of the load electrical equipment is connected to the negative circuit between the circuit breaker QF1 and the three-phase unbalanced transformer.

[0059] Specifically, the Energy Management System (EMS) detects the circuitry of the load-consuming electrical equipment by connecting to a load power detection system.

[0060] The following explanation is provided regarding the high-voltage box, photovoltaic panel (PV), and battery (BAT) involved in this application:

[0061] High-voltage box: In energy storage systems, the high-voltage box is a crucial centralized electrical and mechanical integrated component. It is the core physical carrier and execution unit for the energy management system (EMS) to realize its high-voltage safety management function. The core function of the high-voltage box is to safely and reliably centrally manage the high-voltage main circuit of the battery cluster and provide a key execution interface for the energy management system (EMS).

[0062] Photovoltaic (PV) modules convert solar energy into electrical energy to charge energy storage batteries.

[0063] The battery (BAT) stores electrical energy.

[0064] Working principle of this utility model:

[0065] When in use, it includes the following three modes: peak shaving and valley filling, backup power supply and three-phase imbalance management in the transformer area.

[0066] I. Peak Shaving and Valley Filling Mode Usage Process

[0067] 1. Confirm the start-up conditions and circuit breaker status: Disconnect circuit breaker QF6 as required (cut off the fourth to sixth phase management circuit formed by the photovoltaic energy storage unit through circuit breaker QF6), and close all other circuit breakers (including circuit breakers QF1, QF5, QF8, QF10, and QF9) to ensure that photovoltaic energy storage unit 1, photovoltaic energy storage unit 2, and photovoltaic energy storage unit 3 are connected to the first to third phase management circuits through circuit breakers QF8, QF5, and QF1 respectively, forming a path with the A, B, and C terminals and the neutral N terminal of the three-phase unbalanced transformer.

[0068] 2. Mode Operation Process

[0069] Valley filling phase (off-peak hours): The photovoltaic-storage integrated unit controls the charging of the battery BAT. Priority is given to using photovoltaic (PV) modules to generate electricity, which is then supplied to the integrated unit via circuit breaker QF9, and subsequently charged to the battery BAT via circuit breaker QF10. If the PV output is insufficient, supplementary power is supplied from the mains through the first to third phase management circuits (circuit breaker QF1, meter, circuit breaker QF5, circuit breaker QF8, and circuit breaker QF10) to achieve energy storage during off-peak hours.

[0070] Peak shaving phase (peak hours): The photovoltaic-storage integrated unit controls the discharge of the battery (BAT). The battery energy is output to the photovoltaic-storage integrated unit via circuit breaker QF10 and the high-voltage box, and then transmitted to the three-phase unbalanced transformer and load equipment via circuit breakers QF8, QF10, QF12, QF5, the electricity meter, and circuit breaker QF1, thereby reducing the pressure on the mains power supply during peak hours.

[0071] II. Backup Power Mode Usage Procedure

[0072] 1. Confirm the start-up conditions and circuit breaker status: Disconnect circuit breaker QF5 as required, and close all other circuit breakers (including circuit breakers QF1, QF6, QF7, QF9, and QF10) to ensure that photovoltaic energy storage unit 1, photovoltaic energy storage unit 2, and photovoltaic energy storage unit 3 are connected to the fourth to sixth phase treatment circuits through circuit breakers QF7, QF9, QF6, the meter, and circuit breaker QF1, respectively, and form a circuit with the A, B, and C phases of the three-phase unbalanced transformer and the neutral line N terminal.

[0073] 2. When the load power supply starts, the photovoltaic and energy storage system automatically or manually switches to the backup power mode. The photovoltaic and energy storage unit controls the battery BAT to discharge: the battery energy is output to the photovoltaic and energy storage unit through circuit breaker QF10, and then transmitted to the load electrical equipment through circuit breaker QF7, circuit breaker QF6, electricity meter, and circuit breaker QF1 to provide power to the load.

[0074] Power supply for equipment inside the cabinet: If power is required for the equipment inside the cabinet, the backup power supply is introduced into the equipment inside the cabinet through the circuit breaker QF3 connected in parallel with the positive terminal of the meter through the circuit breaker QF5 in the second phase management circuit and the fifth phase management circuit, or the circuit breaker QF4 in the same position in the third phase and the sixth phase management circuit, to ensure its normal operation.

[0075] III. Application Procedure of Three-Phase Imbalance Management Model in Transformer Areas

[0076] 1. Ensure that circuit breaker QF6 is open (disconnecting the fourth to sixth phase control circuits), and that all other circuit breakers (circuit breakers QF1, QF5, QF8, QF9, and QF10) are closed, so that the first to third phase control circuits are unobstructed:

[0077] The first phase treatment circuit: The positive terminal of the photovoltaic-storage unit 1 is connected to the A terminal of the three-phase unbalanced transformer via circuit breaker QF8, circuit breaker QF5, meter, and circuit breaker QF1 in sequence, and the negative terminal is connected to the neutral line N terminal via the same path;

[0078] The second phase treatment circuit: The positive terminal of the second photovoltaic energy storage unit is connected to the B terminal of the three-phase unbalanced transformer via circuit breaker QF8, circuit breaker QF5, meter, and circuit breaker QF1 in sequence, and the negative terminal is connected to the neutral line N terminal via the same path.

[0079] The third phase treatment circuit: The positive terminal of the photovoltaic-storage unit three is connected to the C terminal of the three-phase unbalanced transformer via circuit breaker QF8, circuit breaker QF5, meter, and circuit breaker QF1 in sequence, and the negative terminal is connected to the neutral line N terminal via the same path.

[0080] 2. Energy Management System (EMS) Startup Check

[0081] The Energy Management System (EMS) is started via the Uninterruptible Power Supply (UPS) (connected via circuit breaker QF2). It is confirmed that the EMS communicates normally with the load power detection device and can collect three-phase load power data.

[0082] IV. Judgment Process:

[0083] 1. Three-phase imbalance detection and strategy formulation parameter acquisition: The Energy Management System (EMS) collects the load power of the three-phase unbalanced transformer at the A, B, and C ends in real time through the load power detection device, and records them as PA (phase A), PB (phase B), and PC (phase C).

[0084] 2. Mean Calculation

[0085] Calculate the average three-phase power: P1 = (PA + PB + PC) / 3.

[0086] Phase Imbalance Judgment

[0087] When PA≥P1 is satisfied, set the 1# unidirectional photovoltaic storage unit to discharge, and set PA = |PA - P1| to perform the discharge operation, and run continuously for 5 minutes. When PA≥P1 is not satisfied, set the 1# unidirectional photovoltaic storage unit to charge, and set Pa = |PA - P1| to perform the charging operation, and run continuously for 5 minutes.

[0088] When PB≥P1 is satisfied, set the #2 unidirectional photovoltaic storage unit to discharge, and set Pb = |PB-P1| to perform the discharge operation, and run continuously for 5 minutes. When PB≥P1 is not satisfied, set the #2 unidirectional photovoltaic storage unit to charge, and set Pb = |PB-P1| to perform the charging operation, and run continuously for 5 minutes.

[0089] When PC≥P1 is satisfied, set the #3 unidirectional photovoltaic storage unit to discharge, and set Pc = |PC-P1| to perform the discharge operation, and run continuously for 5 minutes. When PC≥P1 is not satisfied, set the #3 unidirectional photovoltaic storage unit to charge, and set Pc = |PC-P1| to perform the charging operation, and run continuously for 5 minutes.

[0090] To achieve three-phase power balance adjustment.

[0091] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A photovoltaic-storage system for addressing three-phase imbalance, characterized in that: This includes photovoltaic energy storage unit components, circuit breakers QF8 and QF5, electricity meters, circuit breaker QF1, three-phase unbalanced transformers, circuit breakers QF7 and QF6. The positive terminal of the photovoltaic energy storage unit is connected to the three-phase unbalanced transformer via circuit breaker QF8, circuit breaker QF5, electricity meter, circuit breaker QF1, and the negative terminal of the photovoltaic energy storage unit is connected to the three-phase unbalanced transformer via circuit breaker QF8, circuit breaker QF5, electricity meter, circuit breaker QF1, forming a circuit for grid-connected charging and discharging. The positive terminal of the photovoltaic energy storage unit is connected to the three-phase unbalanced transformer via circuit breaker QF7, circuit breaker QF6, electricity meter, circuit breaker QF1, and the negative terminal of the photovoltaic energy storage unit is connected to the three-phase unbalanced transformer via circuit breaker QF6, electricity meter, circuit breaker QF1, forming a circuit for the off-grid discharge port.

2. A photovoltaic-storage system for addressing three-phase imbalance according to claim 1, characterized in that: The photovoltaic-storage unit assembly includes photovoltaic-storage unit one, photovoltaic-storage unit two, and photovoltaic-storage unit three, with identical layout and composition. Photovoltaic-storage unit one includes port a and port b. The three-phase unbalanced transformer includes terminal A, terminal B, terminal C, and neutral terminal N. The positive terminal of port a of the photovoltaic energy storage unit is connected to terminal A of the three-phase unbalanced transformer in sequence through circuit breaker QF8, circuit breaker QF5, meter, and circuit breaker QF1. The negative terminal of port a of the photovoltaic energy storage unit is connected to terminal N of the neutral line of the three-phase unbalanced transformer in sequence through circuit breaker QF8, circuit breaker QF5, meter, and circuit breaker QF1, thus forming the first phase control circuit. The positive terminal of port a of the second photovoltaic energy storage unit is connected to terminal B of the three-phase unbalanced transformer in sequence through circuit breaker QF8, circuit breaker QF5, meter, and circuit breaker QF1. The negative terminal of port a of the second photovoltaic energy storage unit is connected to terminal N of the neutral line of the three-phase unbalanced transformer in sequence through circuit breaker QF8, circuit breaker QF5, meter, and circuit breaker QF1, thus forming the second phase control circuit. The positive terminal of the photovoltaic energy storage unit's third a port is connected to the C terminal of the three-phase unbalanced transformer via circuit breaker QF8, circuit breaker QF5, electricity meter, and circuit breaker QF1 in sequence. The negative terminal of the photovoltaic energy storage unit's third a port is connected to the neutral N terminal of the three-phase unbalanced transformer via circuit breaker QF8, circuit breaker QF5, electricity meter, and circuit breaker QF1 in sequence, forming the third phase control circuit. The positive terminal of port b of the photovoltaic energy storage unit is connected to terminal A of the three-phase unbalanced transformer in sequence through circuit breaker QF7, circuit breaker QF6, meter, and circuit breaker QF1. The negative terminal of port b of the photovoltaic energy storage unit is connected to terminal N of the neutral line of the three-phase unbalanced transformer in sequence through circuit breaker QF7, circuit breaker QF6, meter, and circuit breaker QF1, thus forming a fourth-phase control circuit. The positive terminal of port 2b of the photovoltaic energy storage unit is connected to terminal B of the three-phase unbalanced transformer in sequence through circuit breaker QF7, circuit breaker QF6, meter, and circuit breaker QF1. The negative terminal of port 2b of the photovoltaic energy storage unit is connected to terminal N of the neutral line of the three-phase unbalanced transformer in sequence through circuit breaker QF7, circuit breaker QF6, meter, and circuit breaker QF1, thus forming the fifth phase control circuit. The positive terminal of the three b-port of the photovoltaic energy storage unit is connected to the C-terminal of the three-phase unbalanced transformer in sequence through circuit breakers QF7, QF6, the meter, and QF1. The negative terminal of the three b-port of the photovoltaic energy storage unit is connected to the neutral N-terminal of the three-phase unbalanced transformer in sequence through circuit breakers QF7, QF6, the meter, and QF1, thus forming the sixth phase control circuit.

3. A photovoltaic-storage system for addressing three-phase imbalance according to claim 2, characterized in that: The photovoltaic-storage unit includes several sets of photovoltaic modules (PV), circuit breakers (QF9), several sets of battery packs (BAT), a high-voltage box, circuit breaker (QF10), and a unidirectional photovoltaic-storage integrated unit. The photovoltaic modules (PV) are connected to the unidirectional photovoltaic-storage integrated unit #1 through circuit breaker (QF9), and the battery packs (BAT) are connected to the unidirectional photovoltaic-storage integrated unit #1 through circuit breaker (QF10). The unidirectional photovoltaic-storage integrated unit #1 is connected to circuit breakers (QF7 and QF8) respectively.

4. A photovoltaic-storage system for addressing three-phase imbalance according to claim 2, characterized in that: In the third-phase management circuit and the sixth-phase management circuit, the positive circuit node between the circuit breaker QF5 and the meter is connected in parallel to the input terminal of the circuit breaker QF4. The output terminal of the circuit breaker QF4 is connected to the power supply of the equipment inside the cabinet. The output terminal of the power supply of the equipment inside the cabinet is connected to the negative circuit node between the circuit breaker QF5 and the meter in the first-phase management circuit and the fourth-phase management circuit.

5. A photovoltaic-storage system for addressing three-phase imbalance according to claim 2, characterized in that: In the second-phase control circuit and the fifth-phase control circuit, the positive circuit node between the circuit breaker QF5 and the meter is connected in parallel to the input terminal of the circuit breaker QF3. The output terminal of the circuit breaker QF3 is connected to the power supply of the equipment inside the cabinet. The output terminal of the power supply of the equipment inside the cabinet is connected to the negative circuit node between the circuit breaker QF5 and the meter in the second-phase control circuit and the fifth-phase control circuit.

6. A photovoltaic-storage system for addressing three-phase imbalance according to claim 2, characterized in that: In the first phase management circuit and the third phase management circuit, the input terminal of circuit breaker QF2 is connected in parallel to the positive circuit node between circuit breaker QF5 and the meter. The output terminal of circuit breaker QF2 is connected to an uninterruptible power supply (UPS). The output terminal of the UPS is connected to an energy management system (EMS). The output terminal of the EMS is connected to the UPS. The UPS is connected to the negative circuit node between circuit breaker QF5 and the meter in the first phase management circuit and the third phase management circuit through circuit breaker QF2.

7. A photovoltaic-storage system for addressing three-phase imbalance according to claim 6, characterized in that: The energy management system (EMS) and the uninterruptible power supply (UPS) are connected in parallel to the fire protection equipment. The output of the fire protection equipment is connected to the UPS. The UPS is connected to the negative circuit node between the circuit breaker QF5 and the meter in the first and third phase treatment circuits through the circuit breaker QF2.

8. A photovoltaic-storage system for addressing three-phase imbalance according to claim 1, characterized in that: The positive circuit between the circuit breaker QF1 and the three-phase unbalanced transformer is connected in parallel to the input terminal of the load electrical equipment, and the output terminal of the load electrical equipment is connected to the negative circuit between the circuit breaker QF1 and the three-phase unbalanced transformer.

9. A photovoltaic-storage system for addressing three-phase imbalance according to claim 7, characterized in that: The Energy Management System (EMS) detects the circuitry of electrical equipment by connecting to a load power detection system.

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