A battery string energy storage system

Abstract

The utility model provides a kind of string type energy storage system, including high pressure chamber, transformer room, PCS rack room and low pressure chamber, the high voltage cabinet in the high pressure chamber is connected with the high voltage winding of transformer room's transformer, the first low voltage winding of transformer in transformer room is connected with the low voltage cabinet in low pressure chamber by cable, it is also connected with the right frame circuit breaker in PCS rack room by copper bar, the second low voltage winding of transformer is connected with the left frame circuit breaker in PCS rack room by copper bar.The utility model is through string type architecture, eliminates inter-cluster circulation, can independently charge-discharge optimization to each cluster battery;Support "building block type" expansion, newly added battery pack is plug and play, without modifying existing system, significantly improve the efficiency, flexibility and safety of energy storage system.

Description

Technical Field

[0001] This utility model belongs to the field of energy storage system technology, specifically, it relates to a string energy storage system. Background Technology

[0002] Energy storage systems store electrical energy in battery clusters during periods of low electricity load and release it during periods of high load. The electricity is then transmitted to the grid via a step-up transformer or directly to users. This approach effectively reduces the power supply pressure on the grid during peak hours, balances power supply and demand, and plays a role in peak shaving and valley filling, thereby significantly optimizing the operating efficiency and stability of the power system. Currently, traditional energy storage systems mostly adopt a centralized architecture, with all battery packs controlled by a single power storage converter (PCS). This centralized design has significant drawbacks: First, due to the "weakest link" effect, the overall system performance is determined by the weakest battery unit, making it impossible to achieve refined management of individual battery clusters, resulting in low system efficiency and insufficient capacity utilization. Second, when multiple battery clusters are connected in parallel, inconsistent battery states (such as SOC and internal resistance) can easily lead to inter-cluster circulating currents, exacerbating battery losses and potentially causing thermal runaway risks. Third, the centralized architecture has poor scalability; adding new battery packs requires modifications to the existing system's main circuitry, failing to meet the flexible expansion requirements of distributed energy storage scenarios. Utility Model Content

[0003] To address the shortcomings of existing technologies, this utility model provides a string energy storage system to solve the problem of the "barrel effect" in traditional centralized energy storage systems, where system performance is limited by the weakest battery cell, making it impossible to achieve refined management of individual batteries, resulting in low efficiency, insufficient capacity utilization, and the risk of thermal runaway due to imbalance between battery clusters.

[0004] The present invention adopts the following technical solution.

[0005] A string energy storage system includes a high-voltage compartment, a transformer compartment, a PCS rack compartment, and a low-voltage compartment. The high-voltage switchgear in the high-voltage compartment is connected to the high-voltage winding of the transformer in the transformer compartment. The first low-voltage winding of the transformer in the transformer compartment is connected to the low-voltage switchgear in the low-voltage compartment via a cable and is also connected to the right frame circuit breaker in the PCS rack compartment via a copper busbar. The second low-voltage winding of the transformer is connected to the left frame circuit breaker in the PCS rack compartment via a copper busbar.

[0006] Furthermore, the high-pressure chamber includes two C-type gas-filled cabinets and one V-type gas-filled cabinet. Each C-type gas-filled cabinet includes a first three-position switch and a first live indicator, and the V-type gas-filled cabinet includes a second three-position switch and a second live indicator.

[0007] One end of each of the two C-type gas-filled switchgear is connected to two incoming cables. Each incoming cable is connected to one end of the first three-position switch in the C-type gas-filled switchgear. The other end of the first three-position switch is connected to one end of the second three-position switch. The other end of the second three-position switch is connected to the high-voltage winding of the transformer in the transformer room.

[0008] One end of the first live indicator is connected to the first three-position switch, and the other end is grounded; one end of the second live indicator is connected to the second three-position switch, and the other end is grounded.

[0009] Furthermore, the V-shaped gas-filled switchgear also includes a first current transformer and a second current transformer. The first current transformer and the second current transformer are fixed in a through-core manner on the cable between the second and third position switches and the high-voltage winding of the transformer. The second current transformer serves as the power supply for the microcomputer protection device on the instrument door of the high-voltage switchgear, with one end connected to the microcomputer protection device and the other end grounded.

[0010] Furthermore, the PCS rack room includes a left rack and a right rack, each rack including an upper compartment and a lower compartment. The upper compartment includes 8 PCS modules, and the lower compartment includes an AC side and a DC side. The AC side includes 16 AC fuses and connecting cables, and the DC side includes 8 DC molded case circuit breakers and connecting cables.

[0011] The lower compartment of the right rack also includes a right frame circuit breaker, and the lower compartment of the left rack also includes a left frame circuit breaker.

[0012] Furthermore, one end of the AC fuse is connected to the busbar via a copper busbar, and the other end is connected to one end of the PCS module via a connecting cable. The other end of the PCS module is connected to the DC molded case circuit breaker via a connecting cable, and the other end of the DC molded case circuit breaker is connected to the battery pack. The left and right racks form 16 string PCS branches.

[0013] Furthermore, the string energy storage system also includes an environmental control section, which includes eight fans. Three of these fans are installed on the door panels of the enclosure to cool the high-pressure and low-pressure chambers; the other five fans are installed in the PCS rack room to cool the PCS rack room.

[0014] Furthermore, the low-voltage cabinet includes a first compartment, a second compartment, a third compartment, and a fourth compartment. The first compartment includes a UPS uninterruptible power supply. The instrument door of the second compartment is equipped with a measurement and control protection device. The power supply terminals of the measurement and control protection device are connected to the measurement and control micro-disconnector of the UPS uninterruptible power supply.

[0015] The fourth compartment includes a control transformer, and the third compartment includes a fifth current transformer, a first fuse, a first surge protector, a second fuse, a second surge protector, a third fuse, a third surge protector, a control transformer upper housing, and a control transformer lower housing.

[0016] One end of the first surge protector is connected to the right rack PCS busbar via the first fuse, and the other end is grounded. One end of the second surge protector is connected to the left rack PCS busbar via the second fuse, and the other end is grounded. One end of the third surge protector is connected to the low-voltage switchgear busbar via the third fuse, and the other end is grounded. One end of the control transformer is connected to the upper housing of the control transformer and connected to the 690V upper power supply. The control transformer converts the 690V voltage to 400V and supplies power to the low-voltage components through the lower housing of the control transformer.

[0017] The beneficial effects of this utility model are as follows, compared with the prior art:

[0018] 1. This application adopts a string design of "one cluster, one converter". Each battery pack is connected to its corresponding PCS module. The electrical connection between clusters is isolated by an independent DC / AC converter module, realizing single-cell charge and discharge control, avoiding inter-cluster circulating current, and improving system efficiency.

[0019] 2. This application includes an environmental control system with 8 fans and an integrated smoke / temperature sensor to monitor the temperature in real time and trigger cooling measures. Fire alarm signals are directly uploaded to the monitoring and protection device to further reduce the risk of thermal runaway.

[0020] 3. This application adopts a modular architecture: the PCS outdoor rack room consists of two standardized racks on the left and right (each rack contains 8 PCS modules and supporting AC / DC components). When adding a battery pack, only the corresponding rack and PCS module need to be added. The battery pack is directly connected through a DC molded case circuit breaker. The AC side cable can be connected to the existing busbar for operation without modifying the existing system. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the primary system of a string energy storage system provided by this utility model;

[0022] Figure 2 This is a schematic diagram of the primary system connection between the high-voltage chamber and the transformer chamber in this utility model;

[0023] Figure 3 This is a schematic diagram of the primary system of the PCS rack room in this utility model;

[0024] Figure 4 This is a schematic diagram of the primary system of the low-pressure chamber in this utility model.

[0025] In the diagram: 1-High voltage compartment; 11-First three-position switch; 12-First live indicator; 13-Second three-position switch; 14-Second live indicator; 15-Incoming cable; 16-First current transformer; 17-Second current transformer; 2-Transformer compartment; 21-High voltage winding; 22-First low voltage winding; 23-Second low voltage winding; 24-Third current transformer; 25-Fourth current transformer; 3-PCS rack compartment; 31-PCS module; 32-AC 33-DC molded case circuit breaker; 34-Right frame circuit breaker; 35-Left frame circuit breaker; 36-Battery pack; 4-Low voltage compartment; 41-UPS uninterruptible power supply; 42-Control transformer; 43-Fifth current transformer; 44-First fuse; 45-First surge protector; 46-Second fuse; 47-Second surge protector; 48-Third fuse; 49-Third surge protector; 410-Upper molded case circuit breaker of control transformer; 411-Lower molded case circuit breaker of control transformer. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. The embodiments described in this application are merely some embodiments of this utility model, and not all embodiments. Based on the spirit of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0027] like Figures 1-4 As shown, a PLC-controlled string energy storage system consists of a PCS rack compartment 3, a low-voltage compartment 4, a transformer compartment 2, a high-voltage compartment 1, and an environmental control system. The high-voltage compartment 1 and the low-voltage compartment 4 are connected to one side of the transformer compartment 2, and the other side of the transformer compartment 2 is connected to the PCS rack compartment 3.

[0028] High-voltage compartment 1 includes two C-type gas-insulated switchgear and one V-type gas-insulated switchgear. Each C-type gas-insulated switchgear includes a first three-position switch 11 and a first live indicator 12. The V-type gas-insulated switchgear includes a second three-position switch 13 and a second live indicator 14. The two C-type gas-insulated switchgears are connected to two incoming cables 15. Each incoming cable 15 is connected to one end of the first three-position switch 11 in the C-type gas-insulated switchgear. The other end of the first three-position switch 11 is connected to one end of the second three-position switch 13. The other end of the second three-position switch 13 is connected to the high-voltage side of the transformer. One end of the first live indicator 12 is connected to the first three-position switch 11, and the other end is grounded. One end of the second live indicator 14 is connected to the second three-position switch 13, and the other end is grounded. Further, the first three-position switch includes a first disconnecting switch QS1 and a first grounding switch DES1. The second three-position switch 13 includes a circuit breaker CB, a second disconnecting switch QS2, and a second grounding switch DES2.

[0029] The V-type gas-insulated switchgear also includes a first current transformer 16 and a second current transformer 17. The first current transformer 16 and the second current transformer 17 are fixed in a through-core manner on the cable between the second three-position switch 13 and the high-voltage winding 21 of the transformer. The second current transformer 17 serves as the power supply for the microcomputer protection device on the instrument door of the high-voltage switchgear, with one end connected to the microcomputer protection device and the other end grounded.

[0030] Transformer compartment 2 includes a double-split transformer, copper busbars, and cables. There is one double-split transformer, which includes one high-voltage winding 21 and two low-voltage windings. The high-voltage winding 21 is connected to the V-type gas-insulated switchgear in high-voltage compartment 1 via a cable. The first low-voltage winding 22 is connected to the low-voltage switchgear in low-voltage compartment 4 via a cable and is also connected to the right frame circuit breaker 34 in PCS rack compartment 3 via a copper busbar. The second low-voltage winding 23 is connected to the left frame circuit breaker 35 in PCS rack compartment 3 via a copper busbar.

[0031] PCS rack compartment 3 includes a left rack and a right rack. Each rack is divided into upper and lower compartments. The upper compartment contains 8 PCS modules 31, and the lower compartment is further divided into an AC side and a DC side. The AC side includes one frame circuit breaker, 16 AC fuses 32, and connecting cables. The DC side includes 8 DC molded case circuit breakers 33 and connecting cables. One end of the AC fuse 32 is connected to the busbar via a copper busbar, and the other end is connected to the PCS module 31 via a 750V 120mm² cable. The other end of the PCS module 31 is connected to the DC molded case circuit breaker 33 via a 3000V 120mm² cable. The other end of the DC molded case circuit breaker 33 is connected to the battery pack 36. The left and right racks form 16 string PCS branches.

[0032] The low-voltage compartment includes one low-voltage cabinet, which comprises four compartments: a first compartment, a second compartment, a third compartment, and a fourth compartment. The first compartment contains a UPS uninterruptible power supply and six batteries. The second compartment contains three multi-function meters, a 100W heating plate, low-voltage terminal blocks, a PLC input / output module, an ESGU (Energy Management Unit), a temperature controller, a DC module, a temperature and humidity controller, several relays, several molded case circuit breakers, and secondary wiring. The transformer compartment 2 also includes a third current transformer 24 and a fourth current transformer 25. The third current transformer 24 is located in the busbar bridge connecting the right frame to the transformer compartment 2, and the fourth current transformer 25 is located in the busbar bridge connecting the left frame to the transformer compartment 2. The instrument door of the second compartment of the low-voltage cabinet includes a measurement and control protection device, a touch screen, PLC operation / fault / alarm indicator lights, and a low-voltage emergency stop button. The top of the low-voltage cabinet also includes a cooling fan for cooling the entire cabinet.

[0033] The first multifunction meter is connected to the measurement and control protection device, and then to the control transformer 42 via a fuse. One end of the first multifunction meter is connected to the third current transformer 24, and the other end is grounded. The second multifunction meter is connected to the measurement and control protection device, and then to the control transformer 42 via a fuse. One end of the second multifunction meter is connected to the fourth current transformer 25, and the other end is grounded. The third multifunction meter is connected to the fifth current transformer 43, and the other end is grounded. The temperature and humidity controller is connected to the cooling fan and heating plate via a relay extension. The cooling fan provides heat dissipation to the low-voltage cabinet, and the heating plate provides heat to the instrument compartment of the low-voltage cabinet. The internal dehumidification function is achieved by connecting the temperature controller to the cooling fan via a relay and starting / stopping the fan by detecting the temperature through a temperature probe. The PLC input / output module power supply is connected to the miniature circuit breaker via a DC module. The PLC input module inputs oil temperature, winding alarm signals, control and protection trip signals, low-voltage cabinet emergency stop signals, and battery compartment emergency stop signals via secondary wires. The PLC output module extends the closing and undervoltage trip signals of the left and right frame circuit breakers via relays, connecting them to the left frame circuit breaker 35 and the right frame circuit breaker 34, and transmitting the signals to the ESGU via a network cable to realize remote control of the two frame circuit breaker closing / opening functions. The power supply terminals of the monitoring and protection device are connected to the monitoring and control micro-circuit of the UPS uninterruptible power supply 41; the power supply terminals of the touch screen are connected to the micro-circuit of the UPS uninterruptible power supply 41 via a DC module to convert the power to 24V; the PLC operation / fault / alarm indicator lights are connected to the PLC output module via secondary wires; the power supply terminals of the low-voltage cabinet emergency stop button are connected to the micro-circuit of the UPS uninterruptible power supply 41 via an extension relay, so that the PCS left and right frame circuit breakers can simultaneously trip undervoltage after the low-voltage cabinet emergency stop button is pressed.

[0034] The fourth compartment of the low-voltage switchgear contains a control transformer 42, and the third compartment contains a fifth current transformer 43, a first fuse 44, a first surge protector 45, a second fuse 46, a second surge protector 47, a third fuse 48, a third surge protector 49, a control transformer upper housing 410, and a control transformer lower housing 411. One end of the first surge protector 45 is connected to the right rack PCS busbar via the first fuse 44, and the other end is grounded. One end of the second surge protector 47 is connected to the left rack PCS busbar via the second fuse 46, and the other end is grounded. One end of the third surge protector 49 is connected to the low-voltage switchgear busbar via the third fuse 48, and the other end is grounded. One end of the control transformer 42 is connected to the control transformer upper housing 410 and connected to a 690V upstream power supply. The control transformer converts the 690V voltage to 400V and supplies power to the low-voltage components via the control transformer lower housing 411.

[0035] The environmental control system includes eight fans: three installed on the enclosure doors to cool the high and low pressure chambers; and five installed at the PCS rack to cool the PCS rack chamber. An integrated smoke / temperature sensor is installed in both the high and low pressure chambers for fire alarm purposes and to transmit smoke signals to the monitoring and protection device on the low-pressure instrument door. Each enclosure door is equipped with a light that illuminates when the enclosure door is opened.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of this utility model. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this utility model should be covered within the protection scope of the claims of this utility model.

Claims

1. A string energy storage system, comprising a high-voltage chamber, a transformer chamber, a PCS rack chamber, and a low-voltage chamber, characterized in that: The high-voltage cabinet in the high-voltage chamber is connected to the high-voltage winding of the transformer in the transformer chamber. The first low-voltage winding of the transformer in the transformer chamber is connected to the low-voltage cabinet in the low-voltage chamber via a cable, and is also connected to the right frame circuit breaker in the PCS rack room via a copper busbar. The second low-voltage winding of the transformer is connected to the left frame circuit breaker in the PCS rack room via a copper busbar.

2. The string energy storage system according to claim 1, characterized in that: The high-pressure chamber includes two C-type gas-filled cabinets and one V-type gas-filled cabinet. Each C-type gas-filled cabinet includes a first three-position switch and a first live indicator. The V-type gas-filled cabinet includes a second three-position switch and a second live indicator. One end of each of the two C-type gas-filled switchgear is connected to two incoming cables. Each incoming cable is connected to one end of the first three-position switch in the C-type gas-filled switchgear. The other end of the first three-position switch is connected to one end of the second three-position switch. The other end of the second three-position switch is connected to the high-voltage winding of the transformer in the transformer room. One end of the first live indicator is connected to the first three-position switch, and the other end is grounded; one end of the second live indicator is connected to the second three-position switch, and the other end is grounded.

3. The string energy storage system according to claim 2, characterized in that: The V-shaped gas-filled switchgear also includes a first current transformer and a second current transformer. The first current transformer and the second current transformer are fixed in a through-core manner on the cable between the second and third position switches and the high-voltage winding of the transformer. The second current transformer serves as the power supply for the microcomputer protection device on the instrument door of the high-voltage switchgear, with one end connected to the microcomputer protection device and the other end grounded.

4. The string energy storage system according to claim 1, characterized in that: The PCS rack room includes a left rack and a right rack. Each rack includes an upper compartment and a lower compartment. The upper compartment includes 8 PCS modules. The lower compartment includes an AC side and a DC side. The AC side includes 16 AC fuses and connecting cables. The DC side includes 8 DC molded case circuit breakers and connecting cables. The lower compartment of the right rack also includes a right frame circuit breaker, and the lower compartment of the left rack also includes a left frame circuit breaker.

5. A string energy storage system according to claim 4, characterized in that: One end of the AC fuse is connected to the busbar via a copper busbar, and the other end is connected to one end of the PCS module via a connecting cable. The other end of the PCS module is connected to the DC molded case circuit breaker via a connecting cable, and the other end of the DC molded case circuit breaker is connected to the battery pack. The left and right racks form 16 string PCS branches.

6. A string energy storage system according to claim 5, characterized in that: The string energy storage system also includes an environmental control section, which includes eight fans. Three of the fans are installed on the door panel of the enclosure to cool the high-pressure chamber and the low-pressure chamber; the other five fans are installed in the PCS rack room to cool the PCS rack room.

7. A string energy storage system according to claim 1, characterized in that: The low-voltage cabinet includes a first compartment, a second compartment, a third compartment and a fourth compartment. The first compartment includes a UPS uninterruptible power supply. The instrument door of the second compartment is equipped with a measurement and control protection device. The power supply terminals of the measurement and control protection device are connected to the measurement and control micro-disconnector of the UPS uninterruptible power supply. The fourth compartment includes a control transformer, and the third compartment includes a fifth current transformer, a first fuse, a first surge protector, a second fuse, a second surge protector, a third fuse, a third surge protector, a control transformer upper housing, and a control transformer lower housing. One end of the first surge protector is connected to the right rack PCS busbar via the first fuse, and the other end is grounded. One end of the second surge protector is connected to the left rack PCS busbar via the second fuse, and the other end is grounded. One end of the third surge protector is connected to the low-voltage switchgear busbar via the third fuse, and the other end is grounded. One end of the control transformer is connected to the upper housing of the control transformer and connected to the 690V upper power supply. The control transformer converts the 690V voltage to 400V and supplies power to the low-voltage components through the lower housing of the control transformer.

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