A module screening method for power system energy storage

Abstract

The present invention provides a module screening method for power system energy storage, the method comprising the following steps: step S1, program startup, matching calculation of the voltage of the power system, and definition of a first input package; step S2, installation matching calculation of the energy storage cabinet of the power system, and definition of a second input package; step S3, power system design matching calculation, and definition of a third input package; step S4, when the output result of the third input package is unique, the process is terminated to achieve optimal module screening for power system energy storage; the present invention can calculate energy storage modules suitable for multiple voltage levels by setting input parameters.

Description

Technical Field

[0001] The present invention relates to the technical field of power system module screening, and in particular to a module screening method applied to power system energy storage. Background Art

[0002] The construction of a new power system with new energy as the main body will lead to major changes in the power supply characteristics and safe operation characteristics of the new power system, and energy storage will play a vital role. At present, electrochemical energy storage represented by LFP has been commercially applied, and energy storage power stations are gradually developing towards the GW level or even the TW level. However, the definition of energy storage modules used in power system energy storage production and integration manufacturers is diverse, forming a variety of systems such as 1000V and 1500V, using thermal management solutions such as air cooling and liquid cooling, and installation methods such as indoor single cabinet, outdoor single cabinet, outdoor container / prefabricated cabin, etc. When integrating the overall solution, the topological solutions used include low-voltage parallel collection, medium- and high-voltage cascade, etc. From the current point of view, there is no unified standard, and the existing module design is also prone to ignore the requirements of cabinet installation and system design matching, resulting in poor modularization of the product.

[0003] The increase in system voltage from 1000V to 1500V has increased system integration and reduced overall costs. The subsequent increase in system voltage to 2000V, 3000V or even higher has caused existing energy storage modules to have relatively poor adaptability to system voltages. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a method for screening energy storage modules that are suitable for multiple voltage levels by setting input parameters.

[0005] The present invention is implemented by the following method: a module screening method applied to power system energy storage, the method comprising the following steps:

[0006] Step S1, the program starts, performs matching calculation on the voltage of the power system, and defines the first input package, and determines whether the output result of the first input package meets the difference ratio between the set system voltage optimal module quantity. If yes, proceed to the next step, otherwise, verify and reset the parameters of the first input package;

[0007] Step S2, performing installation matching calculation on the energy storage cabinet of the power system, defining a second input package, and judging whether the output result of the second input package meets the energy storage cabinet size set by the power system, if yes, proceeding to the next step, if no, rechecking and setting the parameters of the second input package;

[0008] Step S3: power system design matching calculation, define the third input package, determine whether the output result of the third input package meets the design requirements of power system modularization, and whether the output result is unique. If yes, output the result; if not, verify and reset the first input package, and repeat step S1;

[0009] Step S4: When the output result of the third input package is unique, the process ends to achieve the optimal module screening for power system energy storage.

[0010] Furthermore, the first input package in step S1 includes several parameters of power system voltage, battery type, single cell voltage value, number of series or parallel cells in a single module, and allowable value ratio of actual and theoretical calculated difference between series cells.

[0011] Furthermore, the second input package in step S2 includes the size of the energy storage cabinet cells, the selected energy storage cabinet size, the layout design, and the remaining installation parameters of the energy storage cabinet.

[0012] Furthermore, the third input packet in step S3 includes topological requirements of the power system, power of the connected PCS, capacity of the connected boost transformer, and allowable value parameters of the ratio of actual and theoretical differences between the PCS and the boost transformer.

[0013] The beneficial effects of the present invention are as follows: the present invention will meet the optimal LFP module design for power system energy storage of several voltage levels, match and verify it with cabinet installation and system design, and form a product with modularization capability; by screening the optimal LFP module for energy storage, system mismatch is avoided, and at the same time, margins such as PCS and boost transformer are reserved to form active overmatching, which brings favorable conditions for systematically solving problems such as reactive power and station power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the method flow of the present invention.

[0015] Figure 2 This is a calculation example table for the first input package.

[0016] Figure 3 This is a calculation example table for the second input package.

[0017] Figure 4 This is a calculation example table for the third input package. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings.

[0019] See also Figure 1 As shown, a module screening method for power system energy storage of the present invention comprises the following steps:

[0020] Step S1, the program starts, performs matching calculation on the voltage of the power system, and defines the first input package, and determines whether the output result of the first input package meets the difference ratio between the set system voltage optimal module quantity. If yes, proceed to the next step, otherwise, verify and reset the parameters of the first input package;

[0021] Step S2, performing installation matching calculation on the energy storage cabinet of the power system, defining a second input package, and judging whether the output result of the second input package meets the energy storage cabinet size set by the power system, if yes, proceeding to the next step, if no, rechecking and setting the parameters of the second input package;

[0022] Step S3: power system design matching calculation, define the third input package, determine whether the output result of the third input package meets the design requirements of power system modularization, and whether the output result is unique. If yes, output the result; if not, verify and reset the first input package, and repeat step S1;

[0023] Step S4: When the output result of the third input package is unique, the process ends to achieve the optimal module screening for power system energy storage.

[0024] The present invention will be further described below by a specific embodiment:

[0025] Step S1: System voltage matching calculation, define the first input package, the elements include several system voltages that need to be met, battery types, single cell voltage values, the number of series / parallel cells in a single module, the allowable value of the difference ratio between the actual and theoretical calculation of the series cells, etc., judge whether the output result satisfies the difference between the set system voltage optimal module number and is within the allowable range, if so, turn to installation matching calculation, if not, check and reset the parameters of the first input package, and repeat the above operation;

[0026] See also Figure 2 As shown, step S1 is illustrated as follows: according to the current energy storage system voltage Uxt of 1000V and 1500V, and considering the future increase to 2000V and 3000V, a total of 4 system voltages are considered for calculation. Select a mainstream manufacturer's LFP280Ah battery cell, xPyS module (x parallel, y series), and the single cell voltage rating U e / Maximum value U max / Minimum value U min They are 3.2 / 3.6 / 2.8V respectively. The allowable value of the difference ratio between the actual and theoretical calculation of the series-connected cells is Δ A* % is set to 0.65%.

[0027] Use A max =Rounddown(U xt / Umax , 0), calculate the theoretical maximum number of series-connected cells in a single cluster under system voltage A max (pcs). Adopt B max =Rounddown(A max / (x*y), 0), calculate the number of modules B that need to be connected in series in a single cluster max After A act =(x*y)*B max Calculate the maximum number of series cells that can be connected to a single cluster A act (pcs). Using Δ A % = (A max -A act ) / A max *100%, calculate the actual and theoretical difference ratio (%), when Δ A % calculated value is less than Δ A* %, the voltage matching calculation result is matched, otherwise it is mismatched. Through step S1, it can be screened out that the modules that meet the four system voltages of 1000V, 1500V, 2000V, and 3000V are 1P23S, 1P46S, and 1P69S, the modules that meet the three system voltages of 1000V, 2000V, and 3000V are 1P92S, and the modules that meet the two system voltages of 1500V and 3000V are 1P16S, 1P18S, 1P26S, 1P32S, 1P52S, 1P83S, and 1P104S. If the optimal module that only needs to meet two system voltages of 1500V and 3000V is selected, only seven modules, namely 1P16S, 1P18S, 1P26S, 1P32S, 1P52S, 1P83S, and 1P104S, need to be screened in steps S2 and S3.

[0028] Installation matching calculation, define the second input package, the elements include the size of the battery cell, the selected cabinet size, layout design, installation remaining parameters, etc., judge whether the output result meets the set cabinet size. If it meets, transfer to system design matching calculation. If not, check and reset the parameters of the second input package, and repeat the above operation;

[0029] See also Figure 3 As shown, step S2 is illustrated as follows: the size of the indoor cabinet, outdoor cabinet, outdoor prefabricated cabin (container) to be selected is M max According to the LFP 280Ah battery cell size of a mainstream manufacturer, which is 173.9 in width, 71.7 in thickness, and 207.2 in height, the xPyS module is selected, and the internal arrangement order of the module is defined. The number of ax, ay, and az arranged in the three directions of the xyz axis is obtained, and the module size M is obtained. 1; Define the arrangement order in indoor cabinets, outdoor cabinets, and outdoor prefabricated cabins (containers), and the number of b arranged in the three directions of the xyz axis x 、b y 、b z ; Define the main frame structure size M of indoor cabinets, outdoor cabinets, and outdoor prefabricated cabins (containers) 2 , vertical and horizontal dimensions of the wiring trough M 3 , Liquid cooling host and control cabinet size M 4 , calculate the theoretical minimum size M of indoor cabinet, outdoor cabinet and outdoor prefabricated cabin (container) respectively min =b*M 1 +M 2 +M 3 +M 4 , and M max For comparison, if in the three directions of xyz axis, M min All less than M max The voltage matching calculation result is a match, otherwise it is a mismatch. Through step S2, the modules matching the set 25ft container cabinet size can be screened out, including 1P52S and 1P104S, a total of 2 modules, for step S3 screening.

[0030] The system design matching calculation defines the third input package, the elements of which include the system topology requirements, the connected PCS power, the connected transformer capacity, the allowable value of the ratio of the actual and theoretical difference between the PCS and the transformer, and other parameters. It determines whether the output result meets the system modular design requirements and the output result is unique. If it meets the requirements, the output result is transferred. If it does not meet the requirements, the first input package is verified and reset, and the system voltage matching calculation is repeated; PCS is the configuration capacity of the step-up transformer.

[0031] See also Figure 4 As shown, step S3 is illustrated as an example: the system topology to be selected is low-voltage parallel collection or high-voltage direct connection, and the charge and discharge rate P can be selected as 0.25, 0.5 or 1. When low-voltage parallel collection is selected, the xPyS modules selected in steps 1 and 2 are arranged in indoor cabinets, outdoor cabinets, and outdoor prefabricated cabins (containers) to solve the installation capacity S az =a x *a y *a z *b x *b y *b z *280Ah*U e / 10 6 (MWh), select the appropriate PCS capacity S pcs , boost transformer capacity S tb , the allowable value of the difference ratio between the actual and theoretical PCS capacity Δ pcs*% is set to 10%, the allowable value of the difference ratio between the actual and theoretical boost transformer capacity is Δ tb* % is set to 10%. max =Roundup(S az / S pcs / (1 / P), 0), calculate the corresponding number of PCS, using Δ pcs % = (C max *S pcs -S az *P) / C max *S pcs *100%, calculate the actual and theoretical difference ratio (%); use D max =Roundup(S az / (S tb *(1 / P)), 0), calculate the corresponding number of boost transformers, using Δ tb % = (D max *S tb -S az *(1 / P) / D max *S tb *100%, calculate the actual and theoretical difference ratio (%); when Δ pcs % calculated value is greater than Δ pcs* %, when Δ tb % calculated value is greater than Δ tb* %, the system matching calculation judgment result is a match, otherwise it is a mismatch. When the system topology selects high-voltage direct hanging, there is no step-up transformer part verification. Through step S3, it can be concluded that both modules 1P52S and 1P104S meet the system matching calculation. Therefore, the input packages 1, 2, and 3 are set again. When the M2y value in input package 2 is changed from 100 to 200, the 1P52S module cannot match the set 25ft container cabinet size. Only the 1P104S module can match the set 25ft container cabinet size. At this time, the output result is only unique, and the process ends.

[0032] In summary, the present invention proposes an optimal LFP module screening process for power system energy storage. By setting input parameters, system voltage matching calculation, installation matching calculation and system design matching calculation are performed respectively to obtain the optimal module for energy storage that is suitable for as many voltage levels as possible.

[0033] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A module screening method for power system energy storage, characterized in that: The method comprises the following steps: Step S1, the program starts, performs matching calculation on the voltage of the power system, and defines the first input package, and determines whether the output result of the first input package meets the difference ratio between the set system voltage optimal module quantity. If yes, proceed to the next step, otherwise, verify and reset the parameters of the first input package; Step S2, performing installation matching calculation on the energy storage cabinet of the power system, defining a second input package, and judging whether the output result of the second input package meets the energy storage cabinet size set by the power system, if yes, proceeding to the next step, if no, rechecking and setting the parameters of the second input package; Step S3: power system design matching calculation, define the third input package, determine whether the output result of the third input package meets the design requirements of power system modularization, and whether the output result is unique. If yes, output the result; if not, verify and reset the first input package, and repeat step S1; Step S4: when the output result of the third input package is unique, the process ends, and the optimal module screening for power system energy storage is achieved; The first input package in step S1 includes several parameters of power system voltage, battery type, single cell voltage value, number of cells in series or parallel in a single module, and allowable value ratio of actual and theoretical calculated difference between cells in series; The third input packet in step S3 includes the topology requirements of the power system, the power of the connected PCS, the capacity of the connected boost transformer, and the allowable value parameters of the ratio of the actual and theoretical difference between the PCS and the boost transformer.

2. A module screening method for power system energy storage according to claim 1, characterized in that: The second input package in step S2 includes the size of the energy storage cabinet cells, the selected energy storage cabinet size, the layout design, and the remaining installation parameters of the energy storage cabinet.

Images