Equipment for testing grid-connected and off-grid and grid-connected characteristics of energy storage system under power grids with different capacities

Abstract

The utility model discloses equipment for testing grid-connected and off-grid and grid-connected characteristics of an energy storage system under power grids with different capacities. The equipment comprises an input switch, an input filter, a rectifier, an inverter, an output transformer, a bypass switch, a current-limiting inductor input switch, an adjustable inductor and an output filter, the input switch is connected with a power grid, the input switch is connected with the input end of the input filter, the output end of the input filter is connected with the alternating current side of the rectifier, the inverter is connected with the rectifier through a direct current bus, and the alternating current side of the inverter is connected with the input end of the output transformer. The output end of the output transformer is connected with the input ends of the bypass switch and the current-limiting inductance input switch; the test equipment can simulate different short-circuit ratios in a grid-connected test mode and detect the grid-connected characteristics of the tested energy storage equipment connected to power grids with different capacities, and meanwhile, one piece of equipment can have all functions of grid-connected test and off-grid test at the same time.

Description

Technical Field

[0001] The utility model relates to the technical field of power grid detection, in particular to a test device for the grid-connection and off-grid characteristics of an energy storage system and grid-connection characteristics under grids of different capacities. Background Art

[0002] There are some problems with the existing on-grid and off-grid performance testing equipment for electrochemical energy storage systems, two of which are more critical: First, as a grid-connected testing device for electrochemical energy storage devices, the existing testing equipment can only simulate a grid with a single short-circuit ratio, that is, it can only test the grid-connected characteristics of the electrochemical energy storage device under a fixed short-circuit ratio. The test results are not comprehensive enough and cannot well reflect the grid-connected effect of the electrochemical energy storage device under different grid short-circuit ratios, which brings limitations to the test; second, there is a lack of on-grid and off-grid integrated testing equipment for electrochemical energy storage systems, that is, a single testing device can perform both on-grid and off-grid testing, especially the online switching function of on-grid and off-grid testing. Due to the phase jump during the online switching process, the test equipment will trigger the overcurrent protection, causing the test to be interrupted. In summary, in order to speed up the improvement of the detection process of electrochemical energy storage equipment, shorten the detection time, and increase the scope of application of the test results, there is an urgent need for a new type of electrochemical energy storage system testing equipment that is rich in functions, supports on-grid and off-grid integrated testing, and supports online switching testing functions. Utility Model Content

[0003] The technical problem to be solved by the utility model is to propose a test device for the grid-connected and off-grid and grid-connected characteristics of an energy storage system under different capacity grids. The test device for the grid-connected and off-grid and grid-connected characteristics of an energy storage system under different capacity grids can simulate different short-circuit ratios in the grid-connected test mode, detect the grid-connected characteristics of the energy storage device under test connected to grids of different capacities, and at the same time, realize that one device has all the functions of grid-connected test and off-grid test.

[0004] In order to solve the above technical problems, the utility model provides a test device for the grid-connected and off-grid and grid-connected characteristics of an energy storage system under different capacity grids, including an input switch, an input filter, a rectifier, an inverter, an output transformer, a bypass switch, a current-limiting inductor input switch, an adjustable inductor, and an output filter; the input switch is connected to the grid, the input switch is connected to the input end of the input filter, the output end of the input filter is connected to the AC side of the rectifier, the inverter is connected to the rectifier through a DC bus, the AC side of the inverter is connected to the input end of the output transformer, the output end of the output transformer is connected to the input end of the bypass switch and the current-limiting inductor input switch, the output end of the current-limiting inductor input switch is connected to the input end of the adjustable inductor, the output end of the adjustable inductor and the bypass switch is connected to the input end of the output filter, the current-limiting inductor input switch and the adjustable inductor are connected in parallel with the bypass switch, and the output end of the output filter is connected to the energy storage device under test.

[0005] Preferably, when the test device operates in the off-grid test mode, the input switch S1 is closed, the bypass switch S2 is closed, the current-limiting inductor input switch S3 is disconnected, the inverter and the rectifier are operated, and the electric energy flowing into the energy storage device under test is fed back to the power grid, thereby realizing the off-grid characteristic test of the energy storage device under test.

[0006] Preferably, when the test device operates in the grid-connected test mode, the input switch S1 is closed, the bypass switch S2 is opened, and the current-limiting inductor input switch S3 is closed. By adjusting the inductance of the inductor, different short-circuit ratios are simulated in the grid-connected test mode to detect the grid-connected characteristics of the energy storage device under test connected to different weak power grids.

[0007] Preferably, the energy storage device to be tested is an electrochemical energy storage device.

[0008] Preferably, the rectifier and the inverter both use the same two-level converter or multi-level converter.

[0009] Preferably, the rectifier is a three-phase rectifier, and its input is three-phase alternating current.

[0010] Preferably, the inverters are three single-phase inverters, and their outputs are sinusoidal alternating currents with each phase being 120 degrees apart.

[0011] Preferably, the output transformers are three single-phase transformers, each of which is connected to a single-phase inverter on its input side, one of the two ports on the output side of each single-phase inverter is connected together as the midpoint output end of the output transformer, and the other of the two ports on the output side of each single-phase inverter serves as the three-phase AC output end of the output transformer.

[0012] Preferably, the output filter comprises a three-phase filter capacitor.

[0013] After adopting the above equipment, the test equipment for the grid-connected and off-grid and grid-connected characteristics of the energy storage system under different capacity grids includes an input switch, an input filter, a rectifier, an inverter, an output transformer, a bypass switch, a current-limiting inductor input switch, an adjustable inductor, and an output filter; the input switch is connected to the grid, the input switch is connected to the input end of the input filter, the output end of the input filter is connected to the AC side of the rectifier, the inverter is connected to the rectifier through a DC bus, the AC side of the inverter is connected to the input end of the output transformer, and the output end of the output transformer is connected to the bypass switch and the current-limiting inductor. The input end of the input switch, the output end of the current-limiting inductor input switch is connected to the input end of the adjustable inductor, the output ends of the adjustable inductor and the bypass switch are connected to the input end of the output filter, the current-limiting inductor input switch and the adjustable inductor are connected in parallel with the bypass switch, and the output end of the output filter is connected to the energy storage device under test; the test equipment for grid-connected and off-grid and grid-connected characteristics of the energy storage system under different capacity grids can simulate different short-circuit ratios in the grid-connected test mode, detect the grid-connected characteristics of the energy storage device under test connected to grids of different capacities, and at the same time, one device can have all the functions of grid-connected test and off-grid test. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The utility model is a test device for the grid-connected and off-grid energy storage system and the grid-connected characteristics under different capacity grids. Figure 1 ;

[0015] Figure 2 The utility model is a test device for the grid-connected and off-grid energy storage system and the grid-connected characteristics under different capacity grids. Figure 2 .

[0016] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0017] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer and more understandable, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0018] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "front", "back", "left", "right", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0019] Embodiment 1

[0020] See also Figure 1 and Figure 2 , Figure 1 The utility model is a test device for the grid-connected and off-grid energy storage system and the grid-connected characteristics under different capacity grids. Figure 1 ; Figure 2 The utility model is a test device for the grid-connected and off-grid energy storage system and the grid-connected characteristics under different capacity grids. Figure 2 .

[0021] The present embodiment discloses a test device for the grid-connected and off-grid and grid-connected characteristics of an energy storage system under different capacity grids, including an input switch, an input filter 11, a rectifier 12, an inverter 13, an output transformer, a bypass switch, a current-limiting inductor input switch, an adjustable inductor, and an output filter 14; the input switch is connected to the grid, the input switch is connected to the input end of the input filter 11, the output end of the input filter 11 is connected to the AC side of the rectifier 12, the inverter 13 is connected to the rectifier 12 through a DC bus, the AC side of the inverter 13 is connected to the input end of the output transformer, the output end of the output transformer is connected to the input end of the bypass switch and the current-limiting inductor input switch, the output end of the current-limiting inductor input switch is connected to the input end of the adjustable inductor, the output end of the adjustable inductor and the bypass switch is connected to the input end of the output filter 14, the current-limiting inductor input switch and the adjustable inductor are connected in parallel with the bypass switch, and the output end of the output filter 14 is connected to the energy storage device 15 under test.

[0022] Embodiment 2

[0023] This embodiment is based on the first embodiment. In this embodiment, when the test device operates in the off-grid test mode, the input switch S1 is closed, the bypass switch S2 is closed, the current-limiting inductor input switch S3 is disconnected, the inverter 13 and the rectifier 12 are running, and the electric energy flowing into the energy storage device 15 under test is fed back to the power grid, so as to realize the off-grid characteristic test of the energy storage device under test.

[0024] When the test equipment operates in the grid-connected test mode, the input switch S1 is closed, the bypass switch S2 is opened, and the current-limiting inductor input switch S3 is closed. By adjusting the inductance of the inductor, different short-circuit ratios are simulated in the grid-connected test mode to detect the grid-connected characteristics of the energy storage device 15 under different weak power grids.

[0025] Embodiment 3

[0026] This embodiment is based on the first embodiment. In this embodiment, the energy storage device 15 to be tested is an electrochemical energy storage device.

[0027] Embodiment 4

[0028] This embodiment is based on the first embodiment. In this embodiment, the rectifier 12 and the inverter 13 both use the same two-level converter or multi-level converter.

[0029] In this embodiment, the rectifier 12 is a three-phase rectifier 12 whose input is three-phase alternating current.

[0030] The inverters 13 are three single-phase inverters 13 , and their outputs are sinusoidal alternating currents with each phase being 120 degrees apart.

[0031] The output transformers are three single-phase transformers, each of which is connected to a single-phase inverter 13 on its input side. One of the two ports on the output side of each single-phase inverter 13 is connected together as the midpoint output end of the output transformer, and the other of the two ports on the output side of each single-phase inverter 13 serves as the three-phase AC output end of the output transformer.

[0032] The output filter 14 includes three-phase filter capacitors.

[0033] The test equipment for the grid-connected and off-grid and grid-connected characteristics of the energy storage system under different capacity grids can simulate different short-circuit ratios in the grid-connected test mode, detect the grid-connected characteristics of the energy storage device 15 under different capacity grids, and at the same time, realize that one device has all the functions of grid-connected test and off-grid test.

[0034] The preferred embodiments of the present application are described above with reference to the accompanying drawings, but the scope of the present application is not limited thereby. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present application shall be within the scope of the present application.

Claims

1. A test device for the grid-connected and off-grid and grid-connected characteristics of energy storage systems under different capacity grids, characterized in that: The invention comprises an input switch S1, an input filter, a rectifier, an inverter, an output transformer, a bypass switch S2, a current-limiting inductor input switch S3, an adjustable inductor, and an output filter; the input switch S1 is connected to a power grid, the input switch S1 is connected to an input end of an input filter, the output end of the input filter is connected to an AC side of a rectifier, the inverter is connected to the rectifier through a DC bus, the AC side of the inverter is connected to an input end of the output transformer, the output end of the output transformer is connected to an input end of a bypass switch S2 and a current-limiting inductor input switch S3, the output end of the current-limiting inductor input switch S3 is connected to an input end of an adjustable inductor, the output ends of the adjustable inductor and the bypass switch S2 are connected to an input end of an output filter, the current-limiting inductor input switch S3 and the adjustable inductor are connected in parallel with the bypass switch S2, and the output end of the output filter is connected to a measured energy storage device.

2. The test equipment for the on-grid and off-grid characteristics of the energy storage system and the grid-connected characteristics of grids with different capacities according to claim 1 is characterized in that: When the test equipment operates in the off-grid test mode, the input switch S1 is closed, the bypass switch S2 is closed, the current-limiting inductor input switch S3 is disconnected, the inverter and rectifier are running, and the electric energy flowing from the energy storage device under test is fed back to the power grid, thereby realizing the off-grid characteristic test of the energy storage device under test.

3. The test equipment for the on-grid and off-grid characteristics of the energy storage system and the grid-connected characteristics of grids with different capacities according to claim 1 is characterized in that: When the test equipment operates in the grid-connected test mode, the input switch S1 is closed, the bypass switch S2 is opened, and the current-limiting inductor input switch S3 is closed. By adjusting the inductance of the inductor, different short-circuit ratios are simulated in the grid-connected test mode to detect the grid-connected characteristics of the energy storage device under test connected to different weak power grids.

4. The test equipment for the on-grid and off-grid characteristics of the energy storage system and the grid-connected characteristics of grids with different capacities according to claim 1, characterized in that: The energy storage device under test is an electrochemical energy storage device.

5. The test equipment for the on-grid and off-grid characteristics of the energy storage system and the grid-connected characteristics of grids with different capacities according to claim 1, characterized in that: The rectifier and the inverter both use the same two-level converter or multi-level converter.

6. The test equipment for the on-grid and off-grid characteristics of the energy storage system and the grid-connected characteristics of grids with different capacities according to claim 5, characterized in that: The rectifier is a three-phase rectifier, and its input is three-phase alternating current.

7. The test equipment for the on-grid and off-grid characteristics of the energy storage system and the grid-connected characteristics of grids with different capacities according to claim 6, characterized in that: The inverters are three single-phase inverters, and their outputs are sinusoidal alternating currents with each phase being 120 degrees apart.

8. The test equipment for the on-grid and off-grid characteristics of the energy storage system and the grid-connected characteristics of grids with different capacities according to claim 7, characterized in that: The output transformers are three single-phase transformers, each of which is connected to a single-phase inverter on its input side. One of the two ports on the output side of each single-phase inverter is connected together as the midpoint output end of the output transformer, and the other of the two ports on the output side of each single-phase inverter serves as the three-phase AC output end of the output transformer.

9. The test equipment for the grid-connected and off-grid and grid-connected characteristics of the energy storage system according to claim 8, characterized in that: The output filter includes three-phase filter capacitors.

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