CN113541174A

CN113541174A - Energy storage AGC PCS active power distribution method and system considering SOC sequencing

Info

Publication number: CN113541174A
Application number: CN202110774758.0A
Authority: CN
Inventors: 李理; 贺晨; 洪权; 刘伟良; 熊尚峰; 蔡昱华; 吴晋波; 刘志豪; 龚禹生; 肖俊先; 李林山; 陈胜春; 曾林俊; 牟秀君; 吴雪琴; 张伦; 肖纳敏
Original assignee: State Grid Corp of China SGCC; Electric Power Research Institute of State Grid Hunan Electric Power Co Ltd; State Grid Hunan Electric Power Co Ltd; Training Center of State Grid Hunan Electric Power Co Ltd
Current assignee: State Grid Corp of China SGCC; Electric Power Research Institute of State Grid Hunan Electric Power Co Ltd; State Grid Hunan Electric Power Co Ltd; Training Center of State Grid Hunan Electric Power Co Ltd
Priority date: 2021-07-08
Filing date: 2021-07-08
Publication date: 2021-10-22
Anticipated expiration: 2041-07-08
Also published as: CN113541174B

Abstract

The invention discloses a method and a system for distributing PCS active power by energy storage AGC (automatic gain control) considering SOC (state of charge) sequencing, wherein the method comprises the steps of obtaining the SOC value of a battery corresponding to each PCS; sorting the SOC values of the batteries, and setting the priority of each PCS according to the sorting of the SOC values; and sequentially transmitting AGC transmitted power to each PCS in combination with the maximum chargeable/dischargeable maximum power value of each PCS according to the priority of each PCS until all AGC transmitted power is distributed. The invention can give consideration to the requirements of power charge and discharge, battery consistency and SOC balance, and give consideration to the battery consistency and SOC balance in the charge and discharge process under the condition of meeting power scheduling, thereby reducing the inconsistency of the battery and providing the most accurate control information for a power scheduling department.

Description

Energy storage AGC PCS active power distribution method and system considering SOC sequencing

Technical Field

The invention belongs to the technical field of power systems, and particularly relates to a method and a system for distributing active power of a PCS (power storage converter) by energy storage AGC (automatic gain control) in consideration of SOC (system on chip) sequencing.

Background

The large-scale development of electrochemical energy storage puts higher and higher requirements on control equipment, and AGC (automatic gain control) is used as an important module for EMS (energy management system) to carry out system control on an energy storage station, plays a key role in the reasonable distribution of active power and the stable operation of the whole station, so that the control algorithm of the energy storage station is increasingly emphasized. At present, the requirements of energy storage AGC on PCS active power distribution are not determined in national standards and industry standards, and equipment manufacturers respectively provide power distribution algorithms suitable for the characteristics of products of the equipment manufacturers. From the existing literature, the commonly used power allocation algorithm is relatively simple, and usually focuses on meeting the requirement of a certain characteristic. For example, the algorithm for satisfying the power output of each PCS achieves the proportional allocation of the power output based on the capacity of the PCS, and generally does not consider or considers less battery aspects such as battery uniformity and battery cell SOC (state of charge). Under normal conditions, the control algorithm can meet the requirements of each power output, but because the characteristics of the battery are not considered, the consistency of the energy storage system/the battery after long-term operation is greatly different, so that the calculation of the SOC and the charging and discharging control interval are influenced, and finally, the battery unit cannot be controlled normally. Therefore, a power distribution algorithm is needed to meet the requirements of the power charging and discharging capacity of the energy storage power station and the consistency of the battery, so that the output capacity of the energy storage station is ensured, and the energy storage station can operate safely and stably for a long time.

In order to solve the above problems, and finally, bin, monqing, zhouyawa, and so on, a research on operation control strategies of a large battery energy storage power station system (J, power supply, 2021, 38 (3): 78-83) (referred to as document 1) analyzes a battery energy storage power station system control strategy, and proposes an AGC operation mode which can adopt a proportional allocation mode and a battery state of charge (SOC) optimization control mode. In the proportional allocation mode, proportional allocation is performed according to the maximum available power of each PCS that normally operates currently, and the algorithm is shown in formula (1):

in the above formula, P_iThe power value of the ith energy storage converter is obtained; p_i,maxThe maximum chargeable (dischargeable) power value of the energy storage converter i. The method has the advantages of simple algorithm and the defects of large difference of battery units and inaccurate SOC calculation after long-term charge and discharge because the consistency of the battery and the balance of SOC are not considered, and frequent SOC calibration and correction may be needed. Because the scheduling department door carries out positive correlation's correspondence with SOC and capacity, the output ability of energy storage station will all be influenced because SOC is inaccurate or because of the energy storage system is unusable during the demarcation.

And (3) an SOC optimization control mode, namely, the maximum chargeable and dischargeable power value and the SOC of the battery stack are comprehensively considered to distribute the power target value of each PCS, wherein the algorithm is shown as a formula (2).

In the above formula, f_piThe ratio of the maximum chargeable and dischargeable power value of the ith group to the maximum chargeable and dischargeable power value in all the groups is obtained; when calculating the charging power target value, f_siIs the difference between 100% and the percentage value of stack SOC of the ith group. The method has the advantages that the charging and discharging power and SOC balance are comprehensively considered in a weighting mode, so that the power is restricted by an SOC value in the charging and discharging process, and finally the consistency of the battery is better; the disadvantage is that the weight values used are not relevant, the meaning of the different weight values is not clear, and runaway may occur when the weight values are subjected to extreme values. However, the above two common algorithms cannot satisfy the requirements of power charging and discharging, battery consistency and SOC balance well.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: the invention can give consideration to the requirements of power charging and discharging, battery consistency and SOC balance, and can give consideration to the battery consistency and the balance of SOC in the charging and discharging process under the condition of meeting power scheduling, reduce the inconsistency of the battery and provide the most accurate control information for a power scheduling department.

In order to solve the technical problems, the invention adopts the technical scheme that:

a method for distributing PCS active power by energy storage AGC considering SOC sequencing comprises the following steps:

1) acquiring the SOC value of each battery corresponding to the PCS;

2) sorting the SOC values of the batteries, and setting the priority of each PCS according to the sorting of the SOC values;

3) and sequentially transmitting AGC transmitted power to each PCS in combination with the maximum chargeable/dischargeable maximum power value of each PCS according to the priority of each PCS until all AGC transmitted power is distributed.

Optionally, the steps 1) to 3) are based on a preset period t_tickAnd executing in a timed mode.

Optionally, the preset period t_tickGreater than 0.1 second.

Optionally, sorting the SOC values of the batteries in step 2) refers to sorting in order from large to small.

Optionally, step 3) comprises:

3.1) initializing the power to be distributed as AGC total issued power;

3.2) traversing and taking out one PCS with the highest priority from all PCS as the current PCS, if the maximum chargeable/dischargeable maximum power value of the current PCS is smaller than the power to be distributed, taking the maximum chargeable/dischargeable maximum power value of the current PCS as the AGC issued power of the current PCS, otherwise, taking the power to be distributed as the AGC issued power of the current PCS; subtracting the AGC issued power of the current PCS from the power to be distributed to obtain new power to be distributed;

3.3) judging whether the new power to be distributed is greater than 0, and if so, skipping to execute the step 3.2); otherwise, the AGC issued power of each PCS is issued to each PCS.

Optionally, before the step 3.2) of performing the skip in step 3.3), a step of determining whether each PCS has been traversed is further included, and the step 3.2) is performed only if the PCS has not been traversed, otherwise, it is determined that the AGC total transmission power is not matched, and the process is ended and exits.

Optionally, the step 3.3) of sending the AGC down-power of each PCS to each PCS further includes sending the specified active power conversion rate to each PCS, so that each PCS switches from the original AGC down-power to a new AGC down-power according to the specified active power conversion rate.

Optionally, the step 3.3) of sending the AGC power down of each PCS to each PCS further includes sending a specified power adjustment dead zone to each PCS, so that each PCS maintains the current power in the specified power adjustment dead zone, and controls the amount of power deviation exceeding the dead zone after exceeding the specified power adjustment dead zone.

In addition, the invention also provides a system for distributing PCS active power by the energy storage AGC considering the SOC sequencing, which comprises a microprocessor and a memory which are connected with each other, wherein the microprocessor is programmed or configured to execute the steps of the method for distributing PCS active power by the energy storage AGC considering the SOC sequencing.

Furthermore, the present invention also provides a computer readable storage medium having stored therein a computer program programmed or configured to perform the method of distributing PCS active power in consideration of the SOC-sorted energy storage AGC.

Compared with the prior art, the invention has the following advantages:

the invention can give consideration to the requirements of power charge and discharge, battery consistency and SOC balance, and give consideration to the battery consistency and SOC balance in the charge and discharge process under the condition of meeting power scheduling, thereby reducing the inconsistency of the battery and providing the most accurate control information for a power scheduling department.

In order to solve the technical problems, the invention adopts the technical scheme that: the method comprises the steps of obtaining the SOC value of each PCS corresponding to the battery, sequencing the SOC values of the battery, setting the priority of each PCS according to the sequencing of the SOC values, and sequentially sending AGC issued power to each PCS according to the priority of each PCS and combining the maximum chargeable/dischargeable power value of each PCS until the AGC issued power is completely distributed.

Drawings

FIG. 1 is a core flow diagram of a method according to an embodiment of the present invention.

FIG. 2 is a schematic view of a complete flow of the method according to the embodiment of the present invention.

Detailed Description

As shown in fig. 1, the method for distributing PCS active power by the energy storage AGC in the embodiment considering SOC sorting includes:

1) acquiring the SOC value of each battery corresponding to the PCS;

In this embodiment, the steps 1) to 3) are based on a preset period t_tickAnd executing in a timed mode. In this embodiment, a timer is specifically used to control the timing execution of steps 1) to 3), the time of the timer is recorded as t, referring to fig. 2, after each round of executing step 3), if the timer has a time t>A predetermined period t_tickThen execution continues back to step 1).

In general, the predetermined period t_tickAnd the time is more than 0.1 second, and the time can be specifically set according to the requirement.

In this embodiment, sorting the SOC values of the batteries in step 2) means sorting the SOC values in descending order.

In this embodiment, step 3) includes:

3.1) initializing the power to be distributed as AGC total issued power;

In general, the AGC total down-power should be such that less than the maximum chargeable/dischargeable maximum power value sum of the PCS is satisfied. However, in order to prevent the situation that the total AGC delivered power is abnormal, in this embodiment, a step of determining whether each PCS has been traversed is further included before the step 3.2) is executed by skipping in the step 3.3), and the step 3.2 is executed by skipping only when the PCS has not been traversed yet), otherwise, it is determined that the total AGC delivered power is not matched, and the process is ended and exited.

In this embodiment, the step 3.3) of sending the AGC power down of each PCS to each PCS further includes sending the specified active power conversion rate to each PCS, so that each PCS switches from the original AGC power down to a new AGC power down according to the specified active power conversion rate. In the embodiment, the active power conversion rate in the active power distribution algorithm is set manually, so that the adjusting rate is prevented from being too fast or too slow. The designated active power conversion rate is used to convert from the existing operating power to the new set active power at a certain speed after the PCS receives the new set active power. If the active power conversion rate is too small, the conversion process is slow, and quick response is not facilitated; if the active power conversion rate is too high, the conversion process is fast, overshoot mutation is easily caused, and stable control is not facilitated.

In this embodiment, the step 3.3) of sending the AGC power down of each PCS to each PCS further includes sending a specified power adjustment dead zone to each PCS, so that each PCS maintains the current power in the specified power adjustment dead zone, and controls the amount of power deviation exceeding the dead zone after exceeding the specified power adjustment dead zone. The present embodiment can prevent the power from being repeatedly adjusted by artificially setting the power adjustment dead zone. After the power regulation frequency dead zone is set, the existing power can be kept unchanged in the frequency regulation dead zone, and after the power regulation frequency dead zone is exceeded, the control is carried out according to the power deviation amount exceeding the dead zone, so that the PCS is ensured not to frequently act and regulate, and the equipment burden is increased.

Referring to fig. 2, the complete steps of the method of the present embodiment include: 1. inputting control information including the number of available PCS, the maximum active power which can be charged/discharged by each PCS, the SOC value of a battery corresponding to each PCS and AGC (automatic gain control) adjusting power; 2. setting algorithm control parameters including active power conversion rate and power regulation dead zone; 3. sorting, namely sorting the SOCs from large to small at regular time, and setting PCS calling priority according to the sorting result of the SOCs; 4. and issuing control quantity, namely calling priority according to the PCS, and sequentially issuing each PCS output value by the AGC according to the maximum chargeable/dischargeable power value of each PCS.

Referring to fig. 2, step 3) of this embodiment further includes setting the output power of each PCS to zero if a shutdown command is received.

Referring to fig. 2, as a functional package of the energy storage AGC active power distribution method for SOC sorting in this embodiment, a calculation model is established in this embodiment, and input control information is set to be the number of available PCS (PCS _ available _ num), maximum active power that each PCS can charge/discharge (PCS _ power _ max, PCS _ power _ min), Battery SOC value (Battery _ SOC) corresponding to each PCS, and AGC regulated power (AGC _ setvalue). And setting algorithm control parameters including an active Power conversion rate (Power _ conversion _ rate) and a Power regulation dead zone (Power _ dead _ band). As shown in table 1, there are 3 PCS and corresponding battery energy storage units, each PCS has maximum chargeable/dischargeable power, and the SOC of each battery energy storage unit is different. And the power under AGC is output 100kW, and the power distribution to PCS under different algorithms is calculated.

Table 1: and energy storage control parameters.

And step 2) sequencing the SOC values of the batteries to obtain results shown in Table 2.

Table 2: SOC value sorting table.

The PCS control priority is set as shown in table 3.

Table 3: PCS priority ranking table.

And 3) sequentially transmitting AGC transmitted power to each PCS according to the priority of each PCS and combining the maximum chargeable/dischargeable power value of each PCS, wherein the AGC transmitted power required is 100 kW. Calling priority according to the PCS, calling PCS3 firstly, and ensuring that the residual required output power is 70kW after the power of PCS3 is met; next, calling the PCS2, after the control power of the PCS2 is satisfied, the remaining required output power is 30kW, and the 30kW can be borne by the PCS 1. After calculation, the PCS output power is shown in table 4, and the control algorithm can ensure that the SOC of each battery unit can be maximally equalized.

Table 4: the PCS outputs a power meter.

The PCS output powers are calculated according to document 1 and equation (1) of the prior art mentioned in the background of the invention as follows:

PCS1：

PCS2：

PCS3：

after calculation, the PCS output power is shown in table 5, the control algorithm calculates power that the PCS1 can release active power larger, and therefore the actual power allocated to the PCS is larger, but at this time, the SOC of the PCS1 is lower, battery energy will be exhausted faster under high power, and since the SOC balance correction is not considered, the SOC balance of each battery unit will continue to be increased after a period of time, which is not favorable for ensuring the SOC balance of each battery unit, and affects the energy output capability of the whole station.

Table 5: the PCS outputs a power meter.

For example, when power is distributed according to the method of document 1 in the background art, the PCS1 will reach the discharge inhibiting threshold first, and the remaining two units PCS2 and PCS3 will not be able to meet the 100kW power output requirement of AGC demand, and can only discharge according to the sum of the maximum dischargeable power of PCS2 and PCS3 and 70kW, thereby affecting the output capability of the whole station. If power is distributed according to the method for distributing PCS active power by the energy storage AGC with SOC sequencing in the embodiment, the output power of the PCS1 is reduced, the output power of the PCS3 is increased, the PCS1 can run for a long time, and the output capacity of the whole station is ensured.

In addition, the present embodiment also provides a system for distributing PCS active power by the energy storage AGC considering SOC sorting, which includes a microprocessor and a memory connected to each other, wherein the microprocessor is programmed or configured to execute the steps of the aforementioned method for distributing PCS active power by the energy storage AGC considering SOC sorting.

Furthermore, the present embodiment also provides a computer readable storage medium, in which a computer program is stored, which is programmed or configured to execute the method for allocating PCS active power by the energy storage AGC considering the SOC sorting.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-readable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein. The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks. These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.

Claims

1. a method for distributing PCS active power by an energy storage AGC taking into account SOC sorting, is characterized in that, comprising:

1) Obtain the SOC value of the battery corresponding to each PCS;

2) Sort the SOC values of the batteries, and set the priority of each PCS according to the sorting of the SOC values;

3) The power delivered by the AGC is sequentially delivered to each PCS according to the priority of each PCS and combined with the maximum chargeable/dischargeable maximum power value of each PCS until all the power delivered by the AGC is allocated.

2 . The method for allocating PCS active power by an energy storage AGC considering SOC sorting according to claim 1 , wherein steps 1 ) to 3 ) are performed periodically based on a preset period t _tick . 3 .

3 . The method for distributing PCS active power by an energy storage AGC considering SOC sorting according to claim 2 , wherein the preset period t _tick is greater than 0.1 seconds. 4 .

4 . The method for allocating PCS active power by an energy storage AGC considering SOC sorting according to claim 1 , wherein sorting the SOC values of the batteries in step 2) refers to sorting in descending order. 5 .

5. The method for allocating PCS active power by an energy storage AGC considering SOC sorting according to claim 1, wherein step 3) comprises:

3.1) Initialize the to-be-allocated power to be the total AGC sending power;

3.2) Traverse the PCS with the highest priority from each PCS as the current PCS. If the maximum chargeable/dischargeable maximum power value of the current PCS is less than the power to be allocated, the current PCS maximum chargeable/dischargeable maximum power value is used as the current PCS. The AGC sending power of the PCS, otherwise the power to be allocated is used as the AGC sending power of the current PCS; the new power to be allocated is obtained by subtracting the AGC sending power of the current PCS from the power to be allocated;

3.3) Judging whether the new power to be allocated is greater than 0 is established, and if so, skip to step 3.2); otherwise, the AGC issued power of each PCS is issued to each PCS.

6. the method that the energy storage AGC that considers SOC sorting according to claim 5 distributes PCS active power, it is characterized in that, before jumping to execute step 3.2) in step 3.3), also comprise the step of judging whether each PCS traversal is completed, And only jump to step 3.2) if the traversal is not completed, otherwise it is determined that the total AGC issued power does not match, and the process ends and exits.

7. The method for allocating PCS active power by an energy storage AGC taking into account SOC sorting according to claim 5, wherein in step 3.3), when the AGC of each PCS is issued power to each PCS, it also includes issuing a designated The active power conversion rate is given to each PCS, so that each PCS switches from the original AGC delivery power to the delivered new AGC delivery power according to the specified active power conversion rate.

8. the method for allocating PCS active power by the energy storage AGC taking into account SOC sorting according to claim 5, it is characterized in that, in step 3.3), when the AGC power of each PCS is issued to each PCS, it also includes issuing The specified power regulation dead zone is given to each PCS, so that each PCS keeps the existing power unchanged in the specified power regulation dead zone, and is controlled by the power deviation exceeding the dead zone after the specified power regulation dead zone is exceeded.

9. A system for distributing PCS active power by an energy storage AGC taking into account SOC sequencing, comprising an interconnected microprocessor and a memory, characterized in that the microprocessor is programmed or configured to perform any one of claims 1 to 8 A step of a method of distributing PCS active power by an energy storage AGC taking into account SOC sequencing.

10 . A computer-readable storage medium, characterized in that the computer-readable storage medium stores therein an energy storage AGC distribution PCS that is programmed or configured to execute the energy storage AGC ordering according to any one of claims 1 to 8 A computer program for a method of active power.