Energy control planning method for photovoltaic energy storage connected to rail transit main substation

Abstract

The invention provides an energy control planning method for photovoltaic energy storage accessed to a rail transit main substation, which is used for reducing basic electric charge and demand electric charge of the main substation and realizing peak-valley electricity price arbitrage. A main substation is arranged on a rail transit line, a main transformer and a medium-voltage bus are arranged in the main substation, the medium-voltage bus is connected into a three-phase power system through the main transformer, two feedback lines are output from the medium-voltage bus to supply power to other substations along the line, and a photovoltaic power generation system and an energy storage device are connected into the medium-voltage bus through a DC / AC converter device and a step-down transformer respectively. The maximum economic benefit in the whole life cycle of the equipment is taken as a target; the optimal configuration scheme of the energy storage capacity of the energy storage device, the converter capacity of the energy storage device, the charging threshold value of the energy storage device, the discharging threshold value of the energy storage device, the discharging threshold value of the energy storage device in the peak electricity price period, the charging threshold value of the energy storage device in the valley electricity price period and the installation capacity of the photovoltaic power generation device is obtained through an intelligent optimization algorithm.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of rail transit power supply system, and particularly relates to a photovoltaic energy storage energy control planning method for accessing a rail transit main substation. BACKGROUND

[0002] The domestic rail transit electricity charges mostly adopt a two-part electricity pricing charging method, and the electricity charges are generally composed of basic electricity charges, electricity quantity charges, power factor adjustment electricity charges, and various additional charges. The basic electricity charges are mostly measured based on the maximum demand. The rail transit operating line load has obvious peak-valley characteristics. During the morning and evening peak hours, the train dispatching density is high, and the load is at the peak value. During other flat peak hours, the train dispatching density is small, and the load is at the valley value. The basic electricity charges of the main substation are determined by the maximum demand load, and the maximum demand load is determined by the load peak value. The total electricity quantity is the cumulative value of the real-time electricity load within the electricity use time. The electricity quantity charges are collected according to the time period of the day, and are divided into peak electricity prices and valley electricity prices, and the peak electricity price is much higher than the valley electricity price.

[0003] The application of new energy power generation to the rail transit power supply system is one of the current hot research directions of new energy, and the connection of new energy power generation to the rail transit traction power supply system is beneficial to the nearby consumption of clean electricity and the energy saving and emission reduction of the rail transit power supply system. At the same time, it can reduce the electricity absorbed by the main substation from the power grid and reduce the electricity quantity charges.

[0004] In recent years, the energy storage device is a kind of rail transit regenerative power utilization device, which is widely used in the direct current traction system. Its working principle is to monitor the bus voltage of the direct current traction substation, control the energy storage device to release energy to the direct current traction network or absorb energy from the direct current traction network. At present, the energy storage device is only applied to the direct current traction power supply system side, and has no application in the medium voltage side of the rail transit.

[0005] In addition, the domestic train mostly adopts regenerative braking, and the train generates regenerative braking energy when decelerating. According to the monitoring, the train regenerative braking energy cannot be completely consumed and utilized in the power supply system, and the phenomenon of sending energy back to the power grid occurs. The power department adopts the "return not calculated" method for the energy returned by the rail transit, and cannot generate economic benefits.

[0006] In order to reduce the operating cost of the rail transit main substation, the present application proposes a photovoltaic energy storage access scheme and energy control strategy for the rail transit main substation, uses the energy storage device and photovoltaic power generation to jointly reduce the load peak, reduce the maximum demand, thereby reducing the basic electricity charges, and the energy storage device can be used to store the regenerative braking energy, improve the internal consumption rate of the regenerative energy, and the access of the photovoltaic power generation can also reduce the electricity quantity charges. In addition, the energy storage device stores the electric energy in the low electricity price period and releases the electric energy in the high electricity price period, so as to realize the peak-valley electricity price arbitrage and further reduce the electricity quantity charges. SUMMARY

[0007] The purpose of the present application is to provide a photovoltaic energy storage energy control planning method for accessing the main substation of rail transit, which can reduce the basic electricity charge and demand electricity charge of the main substation. The access scheme proposed in the present application has the advantages of easy-to-implement control strategy, simple system structure and high reliability.

[0008] The purpose is achieved by the following technical solutions: A photovoltaic energy storage energy control planning method for accessing the main substation of rail transit, wherein a main substation is arranged on a rail transit line, a main transformer and a medium-voltage bus are arranged in the main substation, the medium-voltage bus is connected to a three-phase power system through the main transformer, two feedback lines are connected to the medium-voltage bus from the main transformer to supply power to other substations along the line, a photovoltaic power generation system and an energy storage device are connected to the medium-voltage bus through DC / AC converters and step-down transformers, respectively. A monitoring device is arranged to detect the traction load power P L , the photovoltaic power generation power P G , the remaining capacity percentage SOC of the energy storage device, and the charge and discharge power P C of the energy storage device in real time, wherein a positive value is recorded when the energy storage device is charged, and a negative value is recorded when the energy storage device is discharged. A controller is arranged to execute a control strategy, receive relevant data detected by the monitoring device, and send control instructions to the energy storage device to control the energy storage device to discharge or charge. An energy control strategy is set as follows: (1) the photovoltaic power generation system preferentially supplies power to the traction load of the medium-voltage bus, and the photovoltaic power generation system charges the energy storage device with the power generation capacity exceeding the demand of the traction load; (2) the train regenerative braking energy that cannot be utilized by the traction load of the medium-voltage bus is used to charge the energy storage device; (3) a discharge capacity threshold SOC 放电 of the energy storage device is set during the peak electricity price period, and a charge capacity threshold SOC 充电 of the energy storage device is set during the Pinggu electricity price period, so that SOC min < SOC 放电 < SOC 充电 < SOC max , wherein SOC min and SOC max represent the minimum and maximum values of the storage capacity of the energy storage device, respectively; (4) the 15min demand power P 15min of the main substation is calculated and recorded by the controller, and two values are set between the maximum and minimum values in the recorded 15min demand power P 15min history data as the action thresholds P 放电 and P 充电 of the energy storage device, and the controller controls the energy storage device according to P 15min , P 放电 , P 充电 and SOC放电 and SOC 充电 performing charge-discharge actions of the energy storage device With the goal of maximizing the economic benefits of the rail transit traction power supply system equipment throughout its life cycle, based on energy control strategies and historical load data of the system, the total energy storage capacity of the energy storage device, the capacity of the energy storage device converter, the energy storage device charging threshold P 充电 , the energy storage device discharge threshold P 放电 , the energy storage device discharge threshold SOC 放电 during the peak electricity price period, the energy storage device charging threshold SOC 充电 during the flat valley electricity price period, and the installed capacity of the photovoltaic power generation system are optimized to obtain the best configuration scheme.

[0009] Further, the calculation formula of the near 15min demand power P 15min of the main substation at the current time t is: When P L ≥ P G > 0, P A = P L - P G When P L < P G , P A = 0, where n 15min represents the number of data points monitored within 15min.

[0010] Further, the energy storage device charge-discharge action strategy is as follows: when P 15min > P 放电 and the current energy of the energy storage device is greater than SOC min , the energy storage device discharges; when P 15min ≤ P 充电 and the current energy of the energy storage device is less than SOC max , the energy storage device charges; when P 充电 < P 15min ≤ P 放电 , if the current time is a flat valley electricity price period, charging the energy storage device by the three-phase power system will not cause the real-time P 15min to be greater than P 放电 , and the energy of the energy storage device after charging at the maximum charging power within the controller reaction step time will not be greater than SOC 充电 , then the energy storage device charges; if the current time is a peak electricity price period, P G > P L ≥ 0, the energy storage device charges, P L ≥ P G > 0 and the energy of the energy storage device is greater than SOC 放电 , the energy storage device discharges.

[0011] Further, when the controller controls the energy storage device to discharge, if P L ≥ P G > 0, the energy storage device discharges to the medium-voltage bus at the maximum discharge power, and the medium-voltage bus load is supplied by the energy storage device, the photovoltaic power generation system and the power system at the same time.

[0012] Further, when the controller controls the energy storage device to charge, the energy storage device charges at the maximum charging power, if P L ≥ P G > 0, the energy storage device is charged by the power system; if 0 ≤ P L < P G , the photovoltaic power generation system preferentially supplies the medium-voltage bus load demand, the remaining power generation of the photovoltaic power generation system is used to charge the energy storage device, and when the actual charging power does not meet the maximum charging power of the energy storage device, the power difference is supplied by the three-phase power system; if P L < 0, the regenerative braking energy generated by the train braking and the photovoltaic power generation system preferentially charge the energy storage device, and when the actual charging power does not meet the maximum charging power of the energy storage device, the power difference is supplied by the three-phase power system.

[0013] Further, the reaction step time of the controller is set to 0.5-2s.

[0014] Compared with the prior art, the present application has the beneficial effects that: 1. The present application uses the energy storage device and the photovoltaic power generation system to reduce the maximum demand electricity fee and the electricity metering fee, the energy control strategy is consistent with the actual electricity metering mode, and the stored electric energy is released at the peak period of electricity price, so that the peak-valley electricity price arbitrage is realized, and the power consumption cost of rail transit can be effectively reduced.

[0015] 2. The system operation mode of the present application is simple and reliable. When the energy storage device or the photovoltaic power generation system fails, it does not affect the normal operation of the power supply system.

[0016] 3. The present application is conducive to local consumption of new energy power generation and reduction of train regenerative electric energy return to the power grid, so that the train regenerative braking energy is consumed in the power supply system.

[0017] 4. In terms of energy control, the mutual cooperation between the energy storage device and the photovoltaic power generation system is realized. When the system load is small and cannot completely consume the photovoltaic power generation power, the energy storage device can absorb the remaining photovoltaic power generation power to improve the energy saving effect. When the system load is large, the photovoltaic power generation system and the energy storage device jointly supply the system load, and the system demand electricity fee is fully reduced.

[0018] 5. The scheme of the present application is applicable to new line construction and existing line reconstruction. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the photovoltaic energy storage access scheme for the traction power supply system in this invention; Figure 2 This is a flowchart of the energy control strategy in this invention; Figure 3 This is the real-time power and demand power curve of the main substation in the case of this invention when energy storage and photovoltaic power generation are not connected; Figure 4 This is the real-time power and demand power curve of the main substation after energy storage and photovoltaic power generation are connected in the case of this invention. Detailed Implementation

[0020] Exemplary embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the invention to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] like Figure 1 As shown, the traction power supply system of the rail transit line is equipped with a main substation, which contains a main transformer and a medium-voltage busbar. The medium-voltage busbar is connected to the three-phase power system through the main transformer, and two feedback lines are output from the medium-voltage busbar to supply power to other substations along the line.

[0022] The photovoltaic power generation system is connected to the medium-voltage bus via DC / AC converter 1 and step-down transformer 1. The energy storage device is connected to the medium-voltage bus via DC / AC converter 2 and step-down transformer 2.

[0023] Monitoring device 1 is installed to detect the traction load power of the medium-voltage busbar in real time, denoted as P. L ; A monitoring device 2 is installed to monitor the remaining power percentage (SOC) and charging / discharging power (P) of the energy storage device in real time. C Charging the energy storage device is recorded as a positive value, and discharging from the energy storage device is recorded as a negative value; monitoring device 3 is set up to detect the photovoltaic power generation in real time and record it as P. G The controller is configured to execute control strategies, receive relevant data from monitoring devices, and send control commands to the energy storage device to control its discharge or charge. The response step time for the controller to execute commands is set to 0.5~2s depending on the specific operating conditions. The controller calculates and records the current status of the main substation. t Power demand P in the last 15 minutes at time15min : Define power P A To calculate the traction load power after deducting the photovoltaic power generation, when P L ≥P G When P > 0, A =P L -P G When P L <P G At that time, P A =0, where n 15min This indicates the number of data points monitored within 15 minutes.

[0024] The energy control strategy proposed in this invention is as follows: (1) The photovoltaic power generation system prioritizes supplying power to the traction load of the medium-voltage bus, and the photovoltaic power generation system uses the power generated beyond the traction load requirement to charge the energy storage equipment.

[0025] (2) Charge the energy storage device with the train regenerative braking energy that cannot be used by the traction load of the medium-voltage bus.

[0026] (3) Set the discharge capacity threshold (SOC) of energy storage devices during peak electricity price periods. 放电 Peace Valley Electricity Price Period Energy Storage Device Charging Capacity Threshold SOC 充电 SOC min <SOC 放电 <SOC 充电 <SOC max SOC min and SOC max These represent the minimum and maximum amounts of electricity that the energy storage device can store, respectively.

[0027] (4) The power demand P recorded for the entire day over 15 minutes 15min Two values, P, are set between the maximum and minimum values ​​in the historical data as the operating threshold for the energy storage device. 放电 and P 充电 When P 15min >P 放电 And the current power of the energy storage device is greater than the state of charge (SOC). min The energy storage device discharges at that time.

[0028] When P 15min ≤P 充电 And the current energy storage device's charge is less than the state of charge (SOC). max The energy storage device is charged during the process.

[0029] When P 充电 <P 15min ≤P 放电When the current time is a flat valley electricity price period, charging the energy storage device by the three-phase power system will not cause real-time P 15min > P 放电 , and the energy storage device is charged at the maximum charging power for a controller reaction step time, and the energy of the energy storage device after charging is not greater than SOC 充电 , the energy storage device charges; when the current time is a peak electricity price period, P G > P L ≥ 0, the energy storage device charges, P L ≥ P G > 0 and the energy of the energy storage device is greater than SOC 放电 , the energy storage device discharges.

[0030] The detailed control process of the energy storage device in the technical scheme is shown in Figure 2 , and is as follows: In the recorded all-day 15min required power P 15min data, two values are selected as the action threshold P 放电 and P 充电 of the energy storage device, P 放电 is recorded as the discharge threshold of the energy storage device, P 充电 is recorded as the charging threshold of the energy storage device, SOC 放电 is recorded as the discharge energy threshold of the energy storage device in the peak electricity price period, and SOC 充电 is recorded as the charging energy threshold of the energy storage device in the flat valley electricity price period.

[0031] S1: The controller receives the real-time load power P L uploaded by the monitoring device 1 and the real-time photovoltaic power P G uploaded by the monitoring device 3, if P L ≥ P G > 0, at this time, the load power is not less than the photovoltaic power, and the load can be completely consumed by the photovoltaic power, so the load is preferentially powered by the photovoltaic power, the electricity charge is reduced, and the remaining load power is supplemented by the power system.

[0032] S1.1: If P 15min > P 放电 , the real-time 15min required power is greater than the discharge threshold of the energy storage device, according to the current SOC of the energy storage device, the energy storage device is controlled to discharge to the medium-voltage bus, and the maximum discharge power is P C , at this time, the energy storage device and the photovoltaic power together discharge to the load, the peak shaving effect is good, the 15min required power is reduced, and the basic electricity charge can be reduced.

[0033] S1.2: If P 充电 < P 15min ≤ P 放电, the real-time 15min demand power is between the discharging threshold and the charging threshold of the energy storage device, and the current load power is greater than 0, according to whether the current time is a peak electricity price period, the working state of the energy storage device is determined.

[0034] S1.2.1: if the current period is in the peak electricity price period and the SOC of the energy storage device is greater than SOC 放电 , the energy storage device is controlled to discharge to the medium-voltage bus, and the maximum discharging power is P C , the electricity cost of the peak period is reduced, peak-valley arbitrage is realized, otherwise the energy storage device is standby.

[0035] S1.2.2: if the current period is in the flat valley electricity price period and charging the energy storage device by the three-phase power system will cause the real-time P 15min to be greater than P 放电 , the energy storage device is standby; otherwise, further judging whether the SOC will be greater than SOC 充电 after the controller is charged by the three-phase power system with the maximum charging power for the step time, if yes, the energy storage device is standby; if no, the energy storage device is charged by the three-phase power system, and the maximum charging power is P C .

[0036] S2: if P L is less than P G , and P L is greater than or equal to 0, the real-time power generation of the photovoltaic power generation system is greater than the traction load of the medium-voltage bus, and the traction load power is not less than 0, the photovoltaic power generation system is preferentially used to supply power to the traction load of the medium-voltage bus, the photovoltaic discharging power is P L , the photovoltaic power generation is consumed, the traction load does not need to take power from the power system, and the electricity cost can be reduced.

[0037] S2.1: if P 15min is greater than P 充电 , the real-time 15min demand power is greater than the charging threshold of the energy storage device, according to the current SOC of the energy storage device, the energy storage device is charged by the photovoltaic power generation system, and the maximum charging power is P C .

[0038] S2.2: if P 15min is less than or equal to P 充电 , the real-time 15min demand power is not greater than the charging threshold of the energy storage device, according to the current SOC of the energy storage device, the energy storage device is preferentially charged by the photovoltaic power generation system, the photovoltaic power generation energy is consumed, and the difference part when the maximum charging power cannot be met is supplemented by the three-phase power system to charge the energy storage device.

[0039] S2.3: if P 充电 is less than P 15min , and P 放电, the real-time 15min demand power is between the discharging threshold and the charging threshold of the energy storage device, and the current load power is greater than 0, according to whether the current time is a peak electricity price period, the working state of the energy storage device is determined.

[0040] S2.3.1: If the current period is in the peak electricity price period, the energy storage device is charged by the photovoltaic power generation system, so as to avoid the increase of electricity cost caused by charging the energy storage device by the power system during the peak electricity price period.

[0041] S2.32: If the current period is in the flat valley electricity price period and charging the energy storage device by the three-phase power system will cause the real-time P 15min > P 放电 , the energy storage device is on standby; otherwise, it is further judged whether the SOC of the energy storage device will be greater than SOC 充电 after charging the energy storage device by the three-phase power system at the maximum charging power for the step time of the controller; if yes, the energy storage device is on standby; if no, the energy storage device is preferentially charged by the photovoltaic power generation system, and the three-phase power system is used to supplement the charging of the energy storage device, and the maximum charging power is P C .

[0042] S3: If P L < 0, according to the current SOC of the energy storage device, the energy storage device is preferentially charged by the train regenerative braking energy and the photovoltaic power generation device, so as to absorb the train regenerative braking energy and consume the photovoltaic power generation, and reduce the electricity cost.

[0043] S3.1: If the current period is in the peak electricity price period, the energy storage device is charged by the train regenerative braking energy and the photovoltaic power generation system, so as to avoid the increase of electricity cost caused by charging the energy storage device by the power system during the peak electricity price period.

[0044] S3.2: If the current period is in the flat valley electricity price period and supplementing the power supply of the energy storage device by the three-phase power system will cause the real-time P 15min > P 放电 , the energy storage device is on standby; otherwise, it is further judged whether the SOC of the energy storage device will be greater than SOC 充电 after charging the energy storage device by the three-phase power system at the maximum charging power for the step time of the controller; if yes, the energy storage device is on standby; if no, the energy storage device is preferentially charged by the train regenerative braking energy and the photovoltaic power generation system, and the three-phase power system is used to supplement the charging of the energy storage device, and the maximum charging power is P C .

[0045] With the maximum economic benefit of the rail transit traction power supply system equipment in the whole life cycle as the target, based on the energy control strategy and the historical load data of the system, the total energy storage capacity of the energy storage device, the converter capacity of the energy storage device and the charging threshold P 充电, the energy storage device discharge threshold P 放电 , the energy storage device discharge power threshold SOC during the peak electricity price period 放电 , the energy storage device charge power threshold SOC during the valley electricity price period 充电 , and the installation capacity of the photovoltaic power generation system is optimized to obtain the optimal configuration scheme.

[0046] Wherein the charge and discharge power P C of the energy storage device is less than or equal to the converter capacity of the energy storage device, the power P G of the photovoltaic power generation system is equal in size to the installation capacity of the photovoltaic power generation system.

[0047] Taking the main substation of a certain engineering line as an example, Figure 3 the real-time power and demand power curve when the energy storage and photovoltaic power generation are not connected is shown in FIG. 1, the maximum demand power is 2.83 MW, and the monthly power consumption is 1.27 million degrees. The optimal configuration is obtained by using the intelligent optimization algorithm, the energy storage capacity of the energy storage device is 1.44 MWh, the capacity of the energy storage device is 0.72 MW, the charge threshold of the energy storage device is 0.57 MW, the discharge threshold of the energy storage device is 2.33 MW, the discharge threshold of the energy storage device during the peak electricity price period is 0.41, the charge threshold of the energy storage device during the valley electricity price period is 0.67, and the installation capacity of the photovoltaic power generation device is 8.60 MW. The real-time power and demand power curve after being regulated by using the energy control strategy proposed is shown in FIG. 2, the maximum demand power is 2.51 MW, and the monthly power consumption is 590,000 degrees. The maximum demand power and the degree of power consumption are effectively reduced. According to the accounting, the demand electricity fee is considered as 35.55 yuan / kVA / month, the degree electricity fee is considered as 0.673 yuan / degree, and the net income of the rail transit traction power supply system equipment within the full life cycle of 25 years is 10119000 yuan, and the total investment cost can be recovered in 7 years. Figure 4

[0048] The above describes the present application in detail through the embodiments, but the content described is only exemplary embodiments of the present application and cannot be considered as limiting the implementation range of the present application. The protection scope of the present application is defined by the claims. Any similar technical solution that utilizes the technical solutions described in the present application or is inspired by the technical solutions of the present application within the essence and protection scope of the present application, achieves the above technical effects, or makes equivalent changes and improvements to the application scope, should still belong to the patent protection scope of the present application. It should be noted that, for the purpose of clear expression, the description of the present application omits the description of some components and processes that are not directly and obviously related to the protection scope of the present application but are known to those skilled in the art.​

Claims

1. A photovoltaic energy storage energy control planning method for accessing a rail transit main substation, characterized in that, The photovoltaic power generation system and the energy storage device are connected to the medium voltage bus through DC / AC conversion devices and voltage reduction transformers respectively; The monitoring device is arranged to detect the traction load power P of the medium-voltage bus in real time L , the photovoltaic power P G , the remaining percentage of the energy storage device SOC, and the charge and discharge power P of the energy storage device C The charging of the energy storage device is positive, and the discharging of the energy storage device is negative. The controller is arranged to execute a control strategy, accept relevant data detected by the monitoring device, and send a control instruction to the energy storage device to control the energy storage device to discharge or charge; Set energy control strategy: (1) photovoltaic power generation system prefer to give traction load power supply, photovoltaic power generation system will exceed the traction load required amount of power generation to charge energy storage device; (2) the traction load cannot be used by the medium voltage bus train regenerative braking energy to charge the energy storage device; (3) set the peak electricity price period energy storage device discharge power threshold SOC 放电 And peaceful valley electricity price period energy storage device charging power threshold SOC 充电 , make SOC min <SOC 放电 <SOC 充电 <SOC max , wherein SOC min And SOC max respectively represent the minimum and maximum value of the energy storage device can store power; (4) by the controller to calculate and record the main substation 15min required power P 15min , in the record of 15min required power P 15min History data between the maximum and minimum value set two values as the action threshold P 放电 And P 充电 , controller according to P 15min , P 放电 , P 充电 And SOC 放电 And SOC 充电 The charge and discharge action of energy storage device is executed; With the maximum economic benefit of rail transit traction power supply system equipment in the whole life cycle as the goal, based on the energy control strategy and the historical load data of the system, the intelligent optimization algorithm including particle swarm optimization algorithm or genetic algorithm is used to optimize the total energy storage capacity of the energy storage device, the converter capacity of the energy storage device, the charging threshold P 充电 of the energy storage device, the discharging threshold P 放电 of the energy storage device, the discharging threshold SOC 放电 of the energy storage device in the peak electricity price period, the charging threshold SOC 充电 of the energy storage device in the valley electricity price period and the installation capacity of the photovoltaic power generation system, so as to obtain the best configuration scheme.

2. The method of claim 1, wherein, The power demand P of the main substation in the last 15 minutes at time t 15min The calculation formula is: When P L ≥P G When P > 0, A =P L -P G When P L <P G At that time, P A =0, where n 15min This indicates the number of data points monitored within 15 minutes.

3. The method of claim 1, wherein, The energy storage device's charging and discharging strategy is as follows: When P 15min >P 放电 And the current power of the energy storage device is greater than the state of charge (SOC). min When the energy storage device discharges, P 15min ≤P 充电 And the current energy storage device's charge is less than the state of charge (SOC). max The energy storage device is charged when P is in use; 充电 <P 15min ≤P 放电 If the current time is during the off-peak electricity price period, charging the energy storage device by the three-phase power system will not cause real-time P. 15min Greater than P 放电 Furthermore, the energy storage device, after being charged at maximum charging power within the controller's response time step, does not exceed the state of charge (SOC). 充电 The energy storage device will then charge; if the current time is during peak electricity price period, P G >P L When P ≥ 0, the energy storage device is charged. L ≥P G >0 and the energy storage device's power is greater than the state of charge (SOC). 放电 At that time, the energy storage device discharges.

4. The method of claim 3, wherein, If P L ≥ P G > 0, the energy storage device discharges to the medium voltage bus at the maximum discharge power, and the medium voltage bus load receives power supply from the energy storage device, the photovoltaic power generation system and the power system simultaneously.

5. The method of claim 3, wherein, The controller controls the energy storage device to charge at the maximum charging power when the energy storage device is charging. If P L ≥ P G > 0, the energy storage device is charged by the power system; if 0 ≤ P L < P G , the photovoltaic power generation system preferentially supplies the medium-voltage bus load demand, the remaining power generation of the photovoltaic power generation system is used for charging the energy storage device, and the power difference part is supplied by the three-phase power system when the actual charging power does not meet the maximum charging power of the energy storage device; if P L < 0, the regenerated braking energy generated by the train braking and the photovoltaic power generation system preferentially charge the energy storage device, and the power difference part is supplied by the three-phase power system when the actual charging power does not meet the maximum charging power of the energy storage device.

6. The method of claim 3, wherein, The reaction step time of the controller is set to 0.5-2s.

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