User side light storage integrated energy grid-connected system

Abstract

The utility model relates to the technical field of power distribution and power utilization, and provides a user side light storage comprehensive energy grid-connected system, an electric connection system comprises a power grid, a power grid side transformation device, a power distribution switch group, a plurality of load transformers, a load bus group, an energy storage device, a metering device and an anti-reflux device, the power distribution switch group is electrically connected with the electrical connection power grid side transformation device, the plurality of load transformers are electrically connected with the electrical connection power distribution switch group, the load bus group is electrically connected with low-voltage sides of the plurality of load transformers, the metering device is electrically connected with a bus of the load bus group, and the energy storage device is electrically connected with the metering device. And the anti-reflux device is electrically connected with the metering device and the power distribution switch group. According to the utility model, the energy storage device is ensured not to flow back to the power grid in the discharging process, the anti-backflow control at the high voltage part of the power grid side is realized, and the safety and reliability of the system are improved.

Description

Technical Field

[0001] This utility model relates to the field of power distribution and consumption technology, and in particular to a user-side integrated photovoltaic and energy storage grid-connected system. Background Technology

[0002] In the field of integrated photovoltaic and energy storage grid-connected systems for industrial and commercial users, with the vigorous promotion of renewable energy and the deepening of energy structure adjustment, the coordinated operation of photovoltaic power generation and energy storage systems has become an important way for industrial and commercial users to reduce electricity costs and optimize their electricity consumption structure. However, existing integrated photovoltaic and energy storage grid-connected systems for users still have a series of problems in practical applications, affecting the system's safety, stability, and economic benefits.

[0003] Chinese patent CN212231107U discloses an energy storage grid-connected structure and grid-connected distribution cabinet. It employs a technique where the grid connection point of the energy storage system is located between the load side of the low-voltage main circuit breaker and the reactive power compensation sampling transformer. Multiple sets of current transformers and multi-function meters are used for backflow prevention control, but this design is only for single-transformer scenarios. However, when the transformer requires maintenance, the low-voltage side bus tie switch closes while the original high- and low-voltage side switches of the transformer open, causing the original low-voltage side backflow prevention device to fail. This prevents the detection of the overall power flow direction, leading to energy flowing back into the grid during the energy storage power station's discharge process. Utility Model Content

[0004] In view of this, this utility model proposes a user-side photovoltaic-storage integrated energy grid-connected system to solve the problem in the prior art where, when the transformer needs maintenance, the low-voltage side bus tie switch is closed while the original high- and low-voltage side switches of the transformer are open, causing the original low-voltage side anti-reverse flow device to fail and unable to detect the overall power flow direction, which leads to the problem of electrical energy flowing back to the grid during the discharge process of the energy storage power station.

[0005] The technical solution of this utility model is implemented as follows: a user-side integrated photovoltaic and energy storage grid-connected system, the system including a power grid, a grid-side transformer, a distribution switch group, multiple load transformers, a load bus group, an energy storage device, a metering device, and an anti-reverse current device, wherein:

[0006] The grid-side transformer is electrically connected to the grid and is used to convert the grid voltage; the distribution switch group is electrically connected to the grid-side transformer; the multiple load transformers are electrically connected to the distribution switch group and are used to reduce the voltage; the load busbar group is electrically connected to the low-voltage side of the multiple load transformers; the metering device is electrically connected to the busbar of the load busbar group and collects current data; the energy storage device is electrically connected to the metering device and is used to store and release energy; the anti-reverse current device is electrically connected to the metering device and the distribution switch group and is used to output current output signals to the energy storage device.

[0007] Based on the above technical solutions, preferably, the anti-backflow device includes a 10KV incoming line switch metering CT, ammeters A1, A2, A3 and high voltage meter U1;

[0008] The A411 terminal of the 10kV incoming line switch metering CT is electrically connected to one end of ammeter A1, and the other end of ammeter A1 is electrically connected to pin 11- of high voltage meter U1. The B411 terminal of the 10kV incoming line switch metering CT is electrically connected to one end of ammeter A2, and the other end of ammeter A2 is electrically connected to pin 12- of high voltage meter U1. The C411 terminal of the 10kV incoming line switch metering CT is electrically connected to one end of ammeter A3, and the other end of ammeter A3 is electrically connected to pin 13- of high voltage meter U1. Pins 11+, 12+, and 13+ of high voltage meter U1 are all grounded.

[0009] Based on the above technical solutions, preferably, the power distribution switch group includes a 10KV incoming switch Q1, a 10KV outgoing switch Q2, and a 10KV outgoing switch Q3;

[0010] The 10kV incoming line switch Q1 is electrically connected to the transformer on the power grid side, and the 10kV incoming line switch Q1 is electrically connected to the 10kV outgoing line switch Q2 and the 10kV outgoing line switch Q3 respectively.

[0011] Based on the above technical solutions, preferably, the plurality of load transformers includes a first transformer and a second transformer;

[0012] The high-voltage side of the first transformer is electrically connected to the 10KV outgoing switch Q3, and the low-voltage side of the first transformer is electrically connected to the metering device and the load busbar group. The high-voltage side of the second transformer is electrically connected to the 10KV outgoing switch Q2, and the low-voltage side of the second transformer is electrically connected to the load busbar group.

[0013] Based on the above technical solutions, preferably, the load busbar group includes a load busbar section I, a load busbar section II, and several low-voltage bus tie switches;

[0014] Section I load busbar and Section II load busbar are electrically connected through several low-voltage bus tie switches. Section I load busbar is electrically connected to the low-voltage side of the first transformer, and Section II load busbar is electrically connected to the low-voltage side of the second transformer.

[0015] Based on the above technical solutions, the preferred option also includes a first industrial and commercial load and a second industrial and commercial load;

[0016] Both the first industrial and commercial load and the second industrial and commercial load are electrically connected to the load busbar group.

[0017] Based on the above technical solutions, preferably, the system also includes an inverter, which is electrically connected to the load transformer.

[0018] Based on the above technical solutions, preferably, the system also includes a photovoltaic module, which is electrically connected to the inverter.

[0019] Based on the above technical solutions, preferably, the metering device adopts a SENTRONPAC4200 meter.

[0020] Based on the above technical solutions, preferably, the energy storage device adopts an energy storage cabinet of model PowerTitan.

[0021] The user-side photovoltaic-storage integrated energy grid-connected system provided by this utility model has the following advantages compared with the prior art:

[0022] (1) By connecting the anti-reverse current device to the metering device and the distribution switch group, the overall power flow direction of multiple load transformers can be effectively monitored at the same time, ensuring that the energy storage device will not flow back to the grid during the discharge process, realizing anti-reverse current control at the high voltage of the grid side, and improving the safety and reliability of the system.

[0023] (2) By using the anti-reverse current device, the 10KV incoming line switch metering CT is directly connected in series with the ammeter and high voltage meter. The segmented busbar design and the configuration of photovoltaic inverters connected to different load transformers have achieved high stability of signal acquisition and optimized configuration of diversified energy sources. This avoids the signal instability problem caused by the secondary CT in the traditional system. At the same time, it solves the technical defect of mutual inhibition when photovoltaic and energy storage systems are connected to the same busbar, so that the two energy systems can operate independently and without interference, maximizing their respective power generation and discharge efficiency. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the system structure of a user-side photovoltaic-storage integrated energy grid-connected system according to the present invention;

[0026] Figure 2 This is a wiring diagram of an anti-backflow device for a user-side photovoltaic-storage integrated energy grid-connected system according to this utility model;

[0027] Figure 3 This is a schematic diagram of an embodiment of a user-side photovoltaic-storage integrated energy grid-connected system according to the present invention. Detailed Implementation

[0028] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0029] Please refer to Figure 1 This utility model provides a user-side integrated photovoltaic and energy storage grid-connected system. The system includes a power grid, a grid-side transformer, a distribution switch group, multiple load transformers, a load bus group, an energy storage device, a metering device, and an anti-reverse current device, wherein:

[0030] The grid-side transformer is electrically connected to the grid and is used to convert the grid voltage; the distribution switch group is electrically connected to the grid-side transformer; the multiple load transformers are electrically connected to the distribution switch group and are used to reduce the voltage; the load busbar group is electrically connected to the low-voltage side of the multiple load transformers; the metering device is electrically connected to the busbar of the load busbar group and collects current data; the energy storage device is electrically connected to the metering device and is used to store and release energy; the anti-reverse current device is electrically connected to the metering device and the distribution switch group and is used to output current output signals to the energy storage device.

[0031] Specifically, this embodiment connects the anti-backflow device to the metering device and the distribution switch group, which can effectively monitor the overall power flow direction of multiple load transformers at the same time, ensuring that the energy storage device does not flow back to the grid during the discharge process. This achieves anti-backflow control at the high voltage of the grid side, improving the safety and reliability of the system.

[0032] The anti-backflow device includes a 10KV incoming line switch metering CT, ammeters A1, A2, A3 and high voltage meter U1;

[0033] The A411 terminal of the 10kV incoming line switch metering CT is electrically connected to one end of ammeter A1, and the other end of ammeter A1 is electrically connected to pin 11- of high voltage meter U1. The B411 terminal of the 10kV incoming line switch metering CT is electrically connected to one end of ammeter A2, and the other end of ammeter A2 is electrically connected to pin 12- of high voltage meter U1. The C411 terminal of the 10kV incoming line switch metering CT is electrically connected to one end of ammeter A3, and the other end of ammeter A3 is electrically connected to pin 13- of high voltage meter U1. Pins 11+, 12+, and 13+ of high voltage meter U1 are all grounded.

[0034] The power distribution switch group includes a 10KV incoming switch Q1, a 10KV outgoing switch Q2, and a 10KV outgoing switch Q3;

[0035] The 10kV incoming line switch Q1 is electrically connected to the transformer on the power grid side, and the 10kV incoming line switch Q1 is electrically connected to the 10kV outgoing line switch Q2 and the 10kV outgoing line switch Q3 respectively.

[0036] The plurality of load transformers includes a first transformer and a second transformer;

[0037] The high-voltage side of the first transformer is electrically connected to the 10KV outgoing switch Q3, and the low-voltage side of the first transformer is electrically connected to the metering device and the load busbar group. The high-voltage side of the second transformer is electrically connected to the 10KV outgoing switch Q2, and the low-voltage side of the second transformer is electrically connected to the load busbar group.

[0038] The load busbar group includes a load busbar section I, a load busbar section II, and several low-voltage bus tie switches;

[0039] Section I load busbar and Section II load busbar are electrically connected through several low-voltage bus tie switches. Section I load busbar is electrically connected to the low-voltage side of the first transformer, and Section II load busbar is electrically connected to the low-voltage side of the second transformer.

[0040] The system also includes a first industrial and commercial load and a second industrial and commercial load;

[0041] Both the first industrial and commercial load and the second industrial and commercial load are electrically connected to the load busbar group.

[0042] The system also includes an inverter that is electrically connected to the load transformer.

[0043] The system also includes photovoltaic modules, which are electrically connected to the inverter.

[0044] This embodiment achieves high stability in signal acquisition and optimized configuration of diversified energy sources by using a specific connection method where the 10KV incoming line switch metering CT is directly connected in series with the ammeter and high-voltage meter through the anti-reverse current device, and the segmented busbar design and the configuration of photovoltaic inverters connected to different load transformers respectively. This avoids the signal instability problem caused by the secondary CT in the traditional system, and solves the technical defect of mutual inhibition when photovoltaic and energy storage systems are connected to the same busbar. This allows the two energy systems to operate independently without interfering with each other, maximizing their respective power generation and discharge efficiency.

[0045] In actual engineering projects, please refer to Figure 3 This is a system schematic diagram of this embodiment, wherein,

[0046] During the installation of the anti-backflow meter, the device can be installed in the high-voltage incoming line cabinet at the top of the transformer. For example... Figure 3 As shown, the grid connection points of the distributed photovoltaic power station and the distributed energy storage power station are located at the low-voltage side of the two transformer loads, respectively. Typically, the anti-reverse current device for the energy storage power station is installed in the low-voltage incoming line cabinet at the grid connection point. The anti-reverse current device is installed after the 10kV incoming line switch Q1. When transformer #1 or #2 is undergoing maintenance, the low-voltage bus tie switch is closed, and the high and low voltage test switches of transformer #1 or #2 are open. If the anti-reverse current meter is installed in the low-voltage side incoming line cabinet, during the peak daytime period, when the discharge power of the photovoltaic power station and the energy storage power station exceeds the sum of the power of the I-section load busbar and the II-section load busbar, an electrical discharge fault will occur during the discharge process of the energy storage power station. In the event of a backflow phenomenon, the anti-backflow meter cannot measure data, and the anti-backflow function fails. In this embodiment, the anti-backflow meter is installed after the 10KV incoming switch Q1. If the above-mentioned operating conditions occur, the anti-backflow meter can measure the current direction and transmit the relevant data to the energy storage system EMS. The EMS system uses logic judgment to control the PCS to reduce power or stop operation. This can prevent backflow during maintenance and repair of the energy storage power station. Under normal operating conditions, it can also play a related role by detecting the load power demand and adjusting the PCS charging and discharging power. Under the premise of ensuring equipment safety, the operating benefits of the energy storage power station can be maximized.

[0047] In one specific embodiment, the metering device is a SENTRONPAC4200 electricity meter.

[0048] In one specific embodiment, the energy storage device uses a PowerTitan energy storage cabinet.

[0049] 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, improvements, etc., 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 user-side integrated photovoltaic and energy storage grid-connected system, characterized in that, The system includes a power grid, a power grid-side transformer, a distribution switchgear, multiple load transformers, a load busbar group, an energy storage device, a metering device, and a reverse current prevention device, wherein: The grid-side transformer is electrically connected to the grid and is used to convert the grid voltage; the distribution switch group is electrically connected to the grid-side transformer; the multiple load transformers are electrically connected to the distribution switch group and are used to reduce the voltage; the load busbar group is electrically connected to the low-voltage side of the multiple load transformers; the metering device is electrically connected to the busbar of the load busbar group and collects current data; the energy storage device is electrically connected to the metering device and is used to store and release energy; the anti-reverse current device is electrically connected to the metering device and the distribution switch group and is used to output current output signals to the energy storage device.

2. The user-side integrated photovoltaic and energy storage grid-connected system as described in claim 1, characterized in that, The anti-backflow device includes a 10KV incoming line switch metering CT, ammeters A1, A2, A3 and high voltage meter U1; The A411 terminal of the 10kV incoming line switch metering CT is electrically connected to one end of ammeter A1, and the other end of ammeter A1 is electrically connected to pin 11- of high voltage meter U1. The B411 terminal of the 10kV incoming line switch metering CT is electrically connected to one end of ammeter A2, and the other end of ammeter A2 is electrically connected to pin 12- of high voltage meter U1. The C411 terminal of the 10kV incoming line switch metering CT is electrically connected to one end of ammeter A3, and the other end of ammeter A3 is electrically connected to pin 13- of high voltage meter U1. Pins 11+, 12+, and 13+ of high voltage meter U1 are all grounded.

3. The user-side integrated photovoltaic and energy storage grid-connected system as described in claim 1, characterized in that, The power distribution switch group includes a 10KV incoming switch Q1, a 10KV outgoing switch Q2, and a 10KV outgoing switch Q3; The 10kV incoming line switch Q1 is electrically connected to the transformer on the power grid side, and the 10kV incoming line switch Q1 is electrically connected to the 10kV outgoing line switch Q2 and the 10kV outgoing line switch Q3 respectively.

4. The user-side integrated photovoltaic and energy storage grid-connected system as described in claim 3, characterized in that, The plurality of load transformers includes a first transformer and a second transformer; The high-voltage side of the first transformer is electrically connected to the 10KV outgoing switch Q3, and the low-voltage side of the first transformer is electrically connected to the metering device and the load busbar group. The high-voltage side of the second transformer is electrically connected to the 10KV outgoing switch Q2, and the low-voltage side of the second transformer is electrically connected to the load busbar group.

5. A user-side integrated photovoltaic and energy storage grid-connected system as described in claim 4, characterized in that, The load busbar group includes a load busbar section I, a load busbar section II, and several low-voltage bus tie switches; Section I load busbar and Section II load busbar are electrically connected through several low-voltage bus tie switches. Section I load busbar is electrically connected to the low-voltage side of the first transformer, and Section II load busbar is electrically connected to the low-voltage side of the second transformer.

6. The user-side integrated photovoltaic and energy storage grid-connected system as described in claim 1, characterized in that, It also includes the first and second industrial and commercial loads; Both the first industrial and commercial load and the second industrial and commercial load are electrically connected to the load busbar group.

7. The user-side integrated photovoltaic and energy storage grid-connected system as described in claim 1, characterized in that, It also includes an inverter, which is electrically connected to the load transformer.

8. A user-side integrated photovoltaic and energy storage grid-connected system as described in claim 7, characterized in that, It also includes photovoltaic modules, which are electrically connected to the inverter.

9. A user-side integrated photovoltaic and energy storage grid-connected system as described in claim 1, characterized in that, The metering device is a SENTRON PAC4200 meter.

10. A user-side integrated photovoltaic and energy storage grid-connected system as described in claim 1, characterized in that, The energy storage device uses a PowerTitan energy storage cabinet.

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