Regulation and control method of energy storage equipment on transformer area side in balance state and fusion Internet of Things terminal

Abstract

The invention relates to a regulation and control method of energy storage equipment on a transformer area side in a balance state and a fusion Internet of Things terminal, and belongs to the field of new energy. The regulation and control method comprises the following steps: according to a local peak-valley electricity price policy, at least dividing regulation and control states of energy storage equipment at a transformer area side into a first valley standby power state, a flat peak holding state, a peak value discharge state and a tail section discharge state; in the first valley standby power state and the flat peak retention state, the charging power of the energy storage equipment is planned according to the electric quantity needing to be reserved by the energy storage equipment at the end of the corresponding time period and the duration of the corresponding time period; in the peak value discharge state, the discharge power of the energy storage equipment is planned according to the electric quantity needing to be reserved by the energy storage equipment when the corresponding time period ends and the duration of the corresponding time period; and in the tail-section discharge state, the discharge power of the energy storage equipment is planned according to the electric quantity in the energy storage equipment when the energy storage equipment enters the tail-section discharge state and the duration of the corresponding time period, so that the electric quantity of the energy storage equipment reaches a first discharge lower limit when the tail-section discharge state is finished. The regulation and control strategy is simple, and cost control is facilitated.

Description

Technical Field

[0001] The present invention relates to a control method for energy storage equipment on a substation side in a balanced state and a fusion Internet of Things terminal, belonging to the field of new energy. Background Art

[0002] Against the backdrop of the "carbon peak and carbon neutrality" goals and the wave of new power system construction, non-traditional loads such as photovoltaics and charging piles have poured in, making the power quality and power balance issues of the substation load rate increasingly prominent. Transformers are still overloaded from time to time in some local areas. In order to increase the service life of the transformer, when the substation load rate is greater than or equal to the alarm threshold of the transformer, some control strategies are usually used to make the substation load rate less than or equal to the safe load rate of the transformer, so that the substation and the power grid are in a balanced state. Among them, the safe load rate of the transformer is less than the heavy overload rate of the transformer.

[0003] After the substation and the power grid are in a balanced state, it is necessary to make full use of the characteristics of the energy storage equipment itself to maximize economic benefits. The Chinese patent invention document with publication number CN118378867A discloses a multi-community energy storage double-layer regulation method, device, equipment and medium. The method obtains the energy storage power usage, energy storage power, energy demand and characteristic parameters of various equipment of users in the community, and the daily fluctuation curve of the power grid electricity price; establishes a community operation model and constraints; the community operation model includes a user energy cost sub-model, a user-configured distributed energy storage sub-model, a multi-community expenditure sub-model, and a photovoltaic power generation output sub-model; the alternating multiplier algorithm and the generalized Nash bargaining theory are used to solve the community operation model to obtain the optimal operation strategy and the optimal transaction electricity price. However, the regulation strategy is complex, has high requirements on hardware equipment, and is not conducive to cost control. Summary of the invention

[0004] The purpose of the present invention is to provide a control method for energy storage equipment on the substation side in a balanced state and a fusion Internet of Things terminal to solve the problems of complex control strategies, high requirements for hardware equipment and high control costs in the prior art.

[0005] To achieve the above object, the solution of the present invention includes:

[0006] The present invention provides a control method for an energy storage device on the side of a substation in a balanced state, comprising: dividing the control state of the energy storage device on the side of the substation into at least a first valley standby state, a flat peak holding state, a peak discharge state and a final discharge state according to the local peak-valley electricity price policy;

[0007] The first valley reserve state is the first valley electricity price period in a day when the photovoltaic power plant is not in use, the flat peak holding state is the flat peak electricity price period in a day, the peak discharge state is the peak electricity price period in a day, and the last discharge state is the non-valley electricity price period in a day when the photovoltaic power plant in the substation is not in use;

[0008] In the first valley backup state and the flat peak maintenance state, the charging power of the energy storage equipment is planned according to the amount of electricity that needs to be reserved by the energy storage equipment at the end of the corresponding period and the duration of the corresponding period;

[0009] In the peak discharge state, the discharge power of the energy storage device is planned according to the amount of electricity that needs to be reserved by the energy storage device at the end of the corresponding period and the duration of the corresponding period;

[0010] In the final discharge state, the discharge power of the energy storage device is planned according to the amount of electricity in the energy storage device when entering the final discharge state and the duration of the corresponding time period, so that the amount of electricity in the energy storage device reaches the first discharge lower limit when the final discharge state ends.

[0011] Furthermore, the peak leveling state further includes: when the first peak load regulation is required, allowing the energy storage device to discharge according to the first peak load regulation discharge power;

[0012] Among them, the first peak-shaving discharge power is the value obtained by deducting the power output of the photovoltaic power in the substation under the flat peak maintenance state from the load of the pure power load in the substation under the flat peak maintenance state and then deducting the safe load rate of the transformer.

[0013] Furthermore, it also includes: a peak discharge state and a valley standby state;

[0014] The peak discharge state is the peak electricity price period of the day, and the valley power reserve state is the other valley electricity price periods of the day;

[0015] In the peak discharge state, the discharge power of the energy storage device is planned according to the amount of electricity that needs to be reserved by the energy storage device at the end of the corresponding period and the duration of the corresponding period;

[0016] In the off-peak backup state, the charging power of the energy storage device is planned according to the amount of power that needs to be reserved by the energy storage device at the end of the corresponding period and the duration of the corresponding period;

[0017] The valley power reserve state further includes: when the energy storage device is charged according to the fifth charging power in the valley power reserve state, it is also determined whether the second peak regulation is required, and when the second peak regulation is required, the energy storage device is discharged according to the second peak regulation discharge power;

[0018] Among them, the second peak-shaving discharge power is the value obtained by deducting the power output of the photovoltaic power in the substation under the valley standby power state from the load of the pure power load in the substation under the valley standby power state and then deducting the safe load rate of the transformer.

[0019] Furthermore, in the first valley backup state, if there is a first overload phenomenon, the energy storage device is charged according to the overload rate of the transformer minus the load of the pure power load of the substation in the first valley backup state and then minus the value of the photovoltaic output power in the substation in the first valley backup state;

[0020] In the flat peak holding state, if there is a second overload phenomenon, the energy storage device is charged according to the value of the photovoltaic output power in the substation under the flat peak holding state plus the overload load rate of the transformer minus the load value of the pure power load in the substation under the flat peak holding state; the safe load rate is less than the overload load rate.

[0021] Furthermore, in the peak discharge state, if it is in the first control state and the photovoltaic power in the current area is not fed back, the energy storage device is discharged according to the difference between the load of the pure power load in the area under the peak discharge state and the power output of the photovoltaic power in the area under the peak discharge state; when the photovoltaic power in the current area is fed back, the energy storage device is charged according to the photovoltaic fed back power;

[0022] The photovoltaic return power is the difference between the photovoltaic output power in the area under the peak discharge state and the load of the pure power load in the area under the peak discharge state;

[0023] If it is not in the first control state and there is a third overload phenomenon, the energy storage device is discharged according to the load of the pure power load in the substation under the peak discharge state minus the photovoltaic output power in the substation under the peak discharge state minus the overload rate of the transformer.

[0024] Furthermore, in the terminal discharge state, if there is a fourth overload phenomenon, the energy storage device is discharged according to the load of the pure power load in the substation in the terminal discharge state minus the overload rate of the transformer and then minus the value of the photovoltaic output power in the substation in the final discharge state;

[0025] If the fourth level of overload does not exist and the overload condition is met, the energy storage device is discharged according to the difference between the load of the pure power load in the area under the terminal discharge state and the photovoltaic output power in the area under the final discharge state.

[0026] Furthermore, in the peak discharge state, if it is in the second control state and the photovoltaic power in the current area is not fed back, the energy storage device is discharged according to the difference between the load of the pure power load in the area under the peak discharge state and the power output of the photovoltaic power in the area under the peak discharge state;

[0027] If the photovoltaic power in the current area is fed back and the conditions for absorbing the photovoltaic fed back discharge are met, the energy storage device is charged according to the preset first rated charging power;

[0028] When not in the second control state, if there is a fifth overload phenomenon, the energy storage device is discharged according to the load of the pure power load in the substation under the peak discharge state minus the photovoltaic output power in the substation under the peak discharge state minus the overload rate of the transformer;

[0029] In the off-peak state, when the second peak regulation is not required and the third generation control state is in place, the energy storage device is charged according to the difference between the photovoltaic output power in the substation under the off-peak state and the pure power load in the substation under the off-peak state;

[0030] When the second peak regulation is not required and the sixth level of overload exists, the energy storage device is charged according to the value of the photovoltaic output power in the substation under the off-peak power state plus the overload load rate of the transformer minus the load value of the pure power load in the substation under the off-peak power state; the safe load rate is less than the overload load rate.

[0031] Furthermore, in the final discharge state, if the value obtained by subtracting the sixth discharge power in the final discharge state from the load of the pure power load in the station area and then subtracting the photovoltaic output power in the station area in the final discharge state is greater than 0, it is considered that the overload condition is met.

[0032] Furthermore, in the peak discharge state, if the value of the photovoltaic output power in the station area under the peak discharge state minus the load of the pure power load in the station area under the peak discharge state is greater than the preset first rated charging power and the charge state of the energy storage device is less than or equal to the preset charge state, it is considered that the conditions for allowing the absorption of photovoltaic return discharge are met;

[0033] Among them, the preset first rated charging power is less than the rated charging power; and the preset state of charge is less than the charging upper limit.

[0034] A fusion IoT terminal of the present invention includes a centralized controller, and the centralized controller is used to execute the control method of the energy storage device on the station side in the equilibrium state as described above.

[0035] The beneficial effects of the present invention are as follows: the present invention is a pioneering invention, which first divides the regulation state of the energy storage device on the substation side into at least the first valley standby state, the flat peak holding state, the peak discharge state and the final discharge state according to the local peak-valley electricity price policy; the first valley standby state is the first valley electricity price period in a day when photovoltaic power is not in use, the flat peak holding state is the flat peak electricity price period in a day, the peak discharge state is the peak electricity price period in a day, and the final discharge state is the non-valley electricity price period in a day when photovoltaic power is not in use in the substation; then, in the first valley standby state and the flat peak holding state, the charging power of the energy storage device is planned according to the amount of electricity that the energy storage device needs to reserve at the end of the corresponding period and the duration of the corresponding period; in the peak discharge state, the discharge power of the energy storage device is planned according to the amount of electricity that the energy storage device needs to reserve at the end of the corresponding period and the duration of the corresponding period; in the final discharge state, the discharge power of the energy storage device is planned according to the amount of electricity in the energy storage device when entering the final discharge state and the duration of the corresponding period, so that the amount of electricity of the energy storage device reaches the first discharge lower limit at the end of the final discharge state. Since the charging and discharging power of the energy storage device can be planned based on the amount of electricity that the energy storage device needs to reserve at the end of the corresponding time period and the length of the corresponding time period, the control strategy is simpler and the cost can be reduced compared to the existing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a flow chart of a method for controlling an energy storage device on a substation side in a balanced state provided by an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of a peak-valley electricity price policy in Henan Province from January to May provided by an embodiment of the present invention;

[0038] Figure 3 It is a flow chart of a control strategy when the regulation state of the energy storage device on the substation side in a balanced state is a first valley backup state provided by an embodiment of the present invention;

[0039] Figure 4 It is a flow chart of a control strategy when the regulation state of the energy storage device on the substation side in a balanced state is a flat peak holding state provided by an embodiment of the present invention;

[0040] Figure 5 It is a flow chart of a control strategy when the regulation state of the energy storage device on the side of the station area in a balanced state is a peak discharge state provided by an embodiment of the present invention;

[0041] Figure 6 It is a flow chart of a control strategy when the regulation state of the energy storage device on the side of the station in a balanced state is a valley charging state provided by an embodiment of the present invention;

[0042] Figure 7It is a flow chart of a control strategy when the regulation state of the energy storage device on the side of the station area in a balanced state is a peak discharge state provided by an embodiment of the present invention;

[0043] Figure 8 It is a flow chart of a control strategy when the regulation state of the energy storage device on the station side in a balanced state is a terminal discharge state provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0045] The idea of ​​the present invention is that when the load rate of the current substation is less than or equal to the safe load rate, it is considered that the current substation and the power grid are in a balanced state. In the balanced state, the photovoltaic in the current substation outputs electric energy according to the optimal output power, and the load of the controllable load equipment in the current substation is not restricted. The energy storage equipment in the current substation discharges or charges according to the output capacity of the photovoltaic to keep the load rate of the substation less than or equal to the safe load rate of the transformer.

[0046] Specifically, according to the local peak-valley electricity price policy, the regulation state of the energy storage equipment on the substation side is divided into at least the first valley backup state, the flat peak holding state, the peak discharge state and the final discharge state, and each regulation state corresponds to a regulation strategy. Among them, the first valley backup state is the first valley electricity price period in a day when photovoltaic power is not working, the flat peak holding state is the flat peak electricity price period in a day, the peak discharge state is the peak electricity price period in a day, and the final discharge state is the non-valley electricity price period in a day when photovoltaic power is not working in the substation. Plan the reserved power required by the energy storage device at the end of each regulation state, and then plan the charging power or discharge power of the state according to the power required to be reserved by the energy storage device and the duration of each regulation state.

[0047] According to the corresponding control strategy, the energy storage equipment is fully utilized to charge as much as possible when the electricity price is low and discharge as much as possible when the price is high, so as to maximize the benefits. In each control strategy, it is also considered whether the load rate of the current substation exceeds the heavy overload rate of the transformer, that is, it is considered whether there is a heavy overload phenomenon in the current substation. If there is a heavy overload phenomenon, adjustments will be made to dynamically maintain the balance between the substation and the power grid.

[0048] An embodiment of a method for regulating an energy storage device on a station side in a balanced state:

[0049] The method of the present invention is implemented on a fusion IoT terminal.

[0050] The fusion IoT terminal has 4G communication functions and various communication interfaces, which are used to collect information such as power and operating status of external devices, and has two-way communication capabilities to send control instructions. The fusion IoT terminal can perform basic logical operations and has the computing functions of a small computer. The computing performance of the fusion IoT terminal is much worse than that of the workstation in terms of computing and storage energy, and is only equivalent to the local control device in edge control technology. The benefit brought by such a hardware carrier is that while meeting the control requirements, the hardware price is only equivalent to one-tenth to one-twentieth of the server price, which is low in cost. At the same time, the hardware volume is greatly reduced, which is convenient for installation in the control box, greatly improving the feasibility of engineering implementation. The energy regulation of the method of the present invention is minute-level control, and the general instruction cycle is more than 5 minutes, so there is no need for excessive hardware computing power.

[0051] The fusion IoT terminal includes a centralized controller, which is responsible for executing a control method of an energy storage device on the side of a station in a balanced state of the present invention. Specifically, reference can be made to Figure 1 .

[0052] When the load rate of the current substation is less than or equal to the safe load rate of the transformer, it is considered that the current substation and the power grid are in a balanced state. The setting of the safe load rate can be set according to actual conditions, and the present invention does not make any special restrictions on this. In order to illustrate the control principle of the control method, the following example is taken as an example that the safe load rate is 75% of the total capacity of the transformer.

[0053] When the load rate of the current substation is greater than or equal to the heavy overload rate of the transformer, it is considered that the current substation has a heavy overload phenomenon. Heavy overload phenomena include reverse heavy overload phenomena and forward heavy overload phenomena. When a heavy overload phenomenon occurs, the charging and discharging power of the energy storage device will be adjusted to eliminate the heavy overload phenomenon. Among them, the setting of the heavy overload rate can be set according to actual conditions. The present invention does not make any special limitations on this. In order to illustrate the control principle of the control method, the heavy overload rate is 80% of the total capacity of the transformer. For example, an exemplary explanation is given below.

[0054] Figure 1 is a flow chart of a method for regulating an energy storage device on a station side in a balanced state provided by an embodiment of the present invention, such as Figure 1 As shown, first, the regulation status of the energy storage equipment on the substation side is divided according to the local peak-valley electricity price policy; secondly, different regulation strategies are called according to different regulation status.

[0055] Specifically, peak and valley electricity prices are charging policies formulated by local relevant departments based on the different electricity demand of users in each time period. Generally speaking, electricity is the cheapest during the period of low electricity demand and the most expensive during the period of peak electricity demand.

[0056] Taking Henan Province as an example, you can refer to Figure 2 , Figure 2 is a schematic diagram of a peak-valley electricity price policy in Henan Province from January to May provided by an embodiment of the present invention, such as Figure 2 As shown, taking January to May, 24 hours a day as an example, the peak and valley electricity price policy is subdivided into each hour, which is called time-of-use electricity price.

[0057] From 0:00 to 7:00 in the morning of January, electricity demand is the lowest, which belongs to the first valley electricity price stage; from 7:00 to 16:00, electricity demand begins to increase, which belongs to the flat peak electricity price stage; from 16:00 to 17:00, electricity demand continues to increase, which belongs to the peak electricity price stage; from 17:00 to 19:00, electricity demand reaches its peak, which belongs to the peak electricity price stage; from 19:00 to 24:00, electricity demand decreases slightly, which belongs to the peak electricity price stage.

[0058] From 0:00 to 7:00 in the morning of February, electricity demand is the lowest, which belongs to the first valley electricity price stage; from 7:00 to 16:00, electricity demand begins to increase, which belongs to the off-peak electricity price stage; from 16:00 to 24:00, electricity demand continues to increase, which belongs to the peak electricity price stage.

[0059] From 0:00 to 6:00 in the morning of March, the electricity demand is the lowest, which belongs to the first valley electricity price stage; from 6:00 to 11:00, the electricity demand begins to increase, which belongs to the peak electricity price stage; from 11:00 to 14:00, the electricity demand decreases, which belongs to the second valley electricity price; from 14:00 to 16:00, the electricity demand begins to increase, which belongs to the peak electricity price stage; from 16:00 to 12:00, the electricity demand continues to increase, which belongs to the peak electricity price stage.

[0060] From 0:00 to 6:00 in the morning of April, the electricity demand is the lowest, which belongs to the first valley electricity price stage; from 6:00 to 11:00, the electricity demand begins to increase, which belongs to the peak electricity price stage; from 11:00 to 14:00, the electricity demand decreases, which belongs to the second valley electricity price; from 14:00 to 16:00, the electricity demand begins to increase, which belongs to the peak electricity price stage; from 16:00 to 12:00, the electricity demand continues to increase, which belongs to the peak electricity price stage.

[0061] From 0:00 to 6:00 in the morning of May, the electricity demand is the lowest, which belongs to the first valley electricity price stage; from 6:00 to 11:00, the electricity demand begins to increase, which belongs to the peak electricity price stage; from 11:00 to 14:00, the electricity demand decreases, which belongs to the second valley electricity price; from 14:00 to 16:00, the electricity demand begins to increase, which belongs to the peak electricity price stage; from 16:00 to 12:00, the electricity demand continues to increase, which belongs to the peak electricity price stage.

[0062] According to the peak-valley electricity prices, the energy storage equipment is divided into six control states, namely the first valley backup state, the flat peak holding state, the peak discharge state, the peak discharge state, the valley backup state and the final discharge state. Each control state corresponds to a control strategy. Among them, the first valley reserve power state is the starting period of the regulation day, which is also the first valley electricity price starting period when photovoltaic power is not in use throughout the day; the flat peak holding state corresponds to the flat peak electricity price period; the peak discharge state corresponds to the peak electricity price period; the peak discharge state corresponds to the peak electricity price period; the valley reserve power state corresponds to the second valley electricity price period in a day; the last discharge state is the ending time period of the regulation day, which is the non-valley electricity price period when photovoltaic power is not in use in the transformer area in a day. The ending time period of the regulation day may be the flat peak electricity price stage, the peak electricity price stage, or the peak electricity price stage. According to historical statistical results, the ending time period of the regulation day will appear more often in the flat peak electricity price stage. Regardless of whether the ending time period of the regulation day is in the flat peak electricity price stage, the peak electricity price stage, or the peak electricity price stage, the energy storage equipment will be regulated to be in a discharge state and be emptied for charging in the next regulation cycle.

[0063] At the beginning of the first valley electricity price of each day, the energy storage device is regulated according to the first valley backup power regulation strategy. After that, the peak-valley electricity price policy is detected at regular intervals, and the corresponding regulation state of the energy storage device is determined according to the detected peak-valley electricity price policy, and then the corresponding regulation strategy is called. In order to make the regulation more accurate, the embodiment of the present invention is exemplified by taking detection every hour as an example.

[0064] After being divided into the regulation state of the energy storage equipment, the energy percentage Qi that needs to be reserved for the energy storage equipment in each regulation state will be determined based on the photovoltaic installed capacity, lighting conditions, installed capacity of the energy storage equipment, typical load curve and peak-valley electricity price policy, so as to facilitate later calls. The determination of Qi is directly related to the degree of realization of the optimal benefit. After planning the energy percentage Qi that needs to be reserved, multiply it by the total power of the energy storage equipment to obtain the power that needs to be reserved for the energy storage equipment.

[0065] As an optional implementation, the binary method can be used to try to figure out the percentage of energy that needs to be reserved under each control state. For example, for a project in Henan Province, the revenue under the typical load curve was calculated using data such as 0%, 50%, and 100% of the reserved energy percentage for the first valley backup state, and then the binary method was used to approximate the optimal solution. It was finally found that the revenue was the largest when the reserved energy percentage was around 40%, so the reserved energy percentage for the first valley backup state was set at 40%.

[0066] As another optional implementation, a particle swarm optimization method may be used to establish a benefit objective function and constraint conditions, find the optimal solution for the benefit, and ultimately obtain the optimal value of the reserved energy percentage under each control state.

[0067] As another optional implementation, an improved flock-of-birds foraging method may be used to seek the optimal value of the reserved energy percentage under each control state.

[0068] Among them, i is 1, 2, 3, 4, 5, 6. Q1 represents the energy percentage reserved in the peak-valley standby state, Q2 represents the energy percentage reserved in the flat-peak holding state, Q3 represents the energy percentage reserved in the peak discharge state, Q4 represents the energy percentage reserved in the peak discharge state, Q5 represents the energy percentage reserved in the valley standby state, and Q6 represents the energy percentage reserved in the final discharge state.

[0069] Combine the following Figure 3 to Figure 8 Describe the control strategies under each control state.

[0070] Control strategy in the first valley backup state:

[0071] For the control strategy when the control state is the first valley backup state, you can refer to Figure 3 , the first valley standby power state is generally at night, when the photovoltaic output capacity is almost 0, that is, the amount of electricity that photovoltaics can output is generally around 0, and the amount of electricity at the beginning of the energy storage device is generally the preset first lower limit value. The present invention does not specifically limit the setting of the preset first lower limit value, and the following illustrative explanation is given by taking the preset first lower limit value of 5% as an example. That is to say, when the state of charge (SOC) of the energy storage device is 5%, it is considered to have reached the first lower limit value. It is understandable that due to the existence of errors, the SOC of the energy storage device at the beginning may not be accurate to 5%. Therefore, within the allowable error range, it is considered that the SOC of the energy storage device at the beginning is 5%.

[0072] Specifically, Figure 3 1 is a flow chart of a control strategy when the regulation state of the energy storage device on the substation side in a balanced state is the first valley backup state provided by an embodiment of the present invention, such as Figure 3 As shown, the first charging power Pj1 of the energy storage device is planned, and the first charging power Pj1 = (Prat*Q1-DCQ1) / T1.

[0073] Among them, Prat is the total power of the energy storage device, DCQ1 represents the power of the energy storage device in the first valley backup state, and T1 represents the total duration of the first valley backup state.

[0074] After planning the first charging power Pj1 of the energy storage device, it is necessary to determine whether the first charging power Pj1 is equal to the rated charging power PCSrat of the energy storage device. 充 In order to protect the energy storage device and reduce the damage rate of the energy storage device, the maximum charging power of the energy storage device cannot exceed the rated charging power PCSrat when charging. 充 .

[0075] If Pj1 is greater than or equal to PCSrat 充 , then the energy storage device is based on PCSrat 充 Charging, if Pj1 is less than PCSrat 充 , the energy storage device is charged according to Pj1.

[0076] Whether the energy storage device is charged according to Pj1 or PCSrat 充 When charging, it is necessary to determine whether the energy storage device has reached the upper limit of charging. If the upper limit of charging is reached, the energy storage device stops charging and maintains the current state, that is, the energy storage device maintains the current SOC. If the upper limit of charging of the energy storage device is not reached, it is necessary to determine whether charging according to the first charging power Pj1 will cause the first overload phenomenon in the substation. If the first overload phenomenon is caused, it is necessary to re-plan the charging power of the energy storage device so that the energy storage device is charged according to the value of BYQ*0.8-T1(K)-GFP1. If the first overload phenomenon is not caused, continue to charge according to the first charging power Pj1.

[0077] Among them, T1(K) represents the load of pure power load in the substation under the first valley backup power state, GFP1 represents the photovoltaic output power in the substation under the first valley backup power state, BYQ represents the total capacity of the transformer, BYQ*0.8 represents 80% of the total capacity of the transformer, which is the alarm threshold.

[0078] The setting of the charging upper limit of the energy storage device is performed according to actual needs, and the present invention does not specifically limit this. The following explanation is given by taking the charging upper limit of the energy storage device being that the SOC of the energy storage device is greater than or equal to 95% as an example.

[0079] Among them, the judgment condition for determining whether the substation will cause the first level of overload phenomenon is: determine whether T1(K)+Pj1-GFP1 is greater than or equal to BYQ*0.8. If T1(K)+Pj1-GFP1≥BYQ*0.8, it is considered that the substation has the first level of overload phenomenon; if T1(K)+Pj1-GFP1<BYQ*0.8, it is considered that the substation does not have the first level of overload phenomenon.

[0080] Among them, T1(K)+Pj1-GFP1 represents the total load in the current substation, that is, the apparent power of the current substation.

[0081] Control strategy during peak-maintaining state:

[0082] For the control strategy when the control state is the flat peak holding state, please refer to Figure 4In this state, the energy storage device is basically kept near the planned reserved energy Q2 without charging or discharging, but it is necessary to always prevent the possible heavy overload in the station area. In this state, photovoltaics will generally generate electricity. When photovoltaics generate feedback, in order to ensure the profit, the energy storage device will be selectively charged.

[0083] Specifically, Figure 4 : is a flow chart of a control strategy when the regulation state of the energy storage device on the substation side in a balanced state is a flat peak holding state provided by an embodiment of the present invention, such as Figure 4 As shown, the second charging power Pj2 of the energy storage device is planned, and the second charging power Pj2 = (DCQ2-Prat*Q2) / T2.

[0084] Among them, DCQ2 represents the power of the energy storage device in the flat peak holding state, and T2 represents the total duration of the flat peak holding state.

[0085] After planning the second charging power Pj2 of the energy storage device, it is necessary to determine whether the second charging power Pj2 is equal to the rated charging power PCSrat of the energy storage device. 充 In order to protect the energy storage device and reduce the damage rate of the energy storage device, the maximum charging power of the energy storage device cannot exceed the rated charging power PCSrat when charging. 充 .

[0086] If Pj2 is greater than or equal to PCSrat 充 , then the energy storage device is based on PCSrat 充 Charging, if Pj2 is less than PCSrat 充 , the energy storage device is charged according to Pj2.

[0087] Whether the energy storage device is charged according to Pj2 or PCSrat 充 When charging, it is necessary to determine whether the first peak regulation is needed. If the first peak regulation is needed, it is necessary to first determine whether the charge state of the energy storage device reaches the first lower limit. If the first peak regulation is not needed, it is necessary to determine whether the charge state of the energy storage device is greater than the second reserved energy percentage. The second reserved energy percentage is Q2, that is, the energy percentage reserved in the flat peak maintenance state.

[0088] Among them, the condition for judging whether the first peak adjustment is needed is: judging whether T2(K)-GFP2 is greater than or equal to BYQ*0.75. If T2(K)-GFP2≥BYQ*0.75, it is considered that the first peak adjustment is needed; if T2(K)-GFP2<BYQ*0.75, it is considered that the first peak adjustment is not needed.

[0089] Among them, T2(K)-GFP2 represents the total load in the current area, that is, the apparent power of the current area. The total load in the current area was originally supposed to include energy storage equipment, but because the planned energy storage equipment is neither charged nor discharged under this control state, the energy storage equipment is 0 in mathematical expression, so the total load in the current area only includes pure electricity load and photovoltaic.

[0090] Among them, T2(K) represents the load of pure electricity load in the substation under the flat peak maintenance state, GFP2 represents the photovoltaic output power in the substation under the flat peak maintenance state, and BYQ*0.75 represents 75% of the total capacity of the transformer, which is the safe load rate.

[0091] It is determined whether the state of charge of the energy storage device reaches a first lower limit. If so, it means that the energy storage device currently has no electricity to discharge and cannot perform peak load regulation. The energy storage device maintains the current SOC and is neither charged nor discharged. If the first lower limit is not reached, it means that the energy storage device currently has electricity to discharge, and the energy storage device discharges according to the first peak load regulation discharge power.

[0092] When the energy storage device discharges according to the first peak-shaving discharge power, it is necessary to determine whether the first peak-shaving discharge power is less than the rated discharge power PCSrat of the energy storage device. 充 If it is less than, the energy storage device discharges according to the first peak-shaving discharge power to achieve peak-shaving. If it is greater than or equal to, the energy storage device discharges according to the rated discharge power PCSrat 充 Discharge to achieve peak load regulation.

[0093] The first peak-shaving discharge power is a value of T2(K)-GFP2-BYQ*0.75.

[0094] The purpose of determining whether the state of charge of the energy storage device has reached the first lower limit is to prevent the energy storage device from being discharged when it has no electricity, thereby reducing damage to the energy storage device and increasing the service life of the energy storage device.

[0095] Among them, the condition for judging whether the state of charge of the energy storage device reaches the first lower limit is: whether the SOC of the energy storage device is less than or equal to 5%. If the SOC value is ≤5%, it is considered that the state of charge of the energy storage device has reached the lower limit; if the SOC value is greater than 5%, it is considered that the state of charge of the energy storage device has not reached the lower limit.

[0096] When the first peak regulation is not needed, continue to judge whether the state of charge of the energy storage device is greater than Q2. If the SOC of the energy storage device is greater than Q2, it means that the current amount of electricity stored in the energy storage device is sufficient for later use, and the state of the energy storage device is maintained, so that the energy storage device is neither charged nor discharged; if the SOC of the energy storage device is less than or equal to Q2, it means that the current amount of electricity stored in the energy storage device is small and insufficient for later use, and further charging is required.

[0097] When the energy storage device needs to continue charging, it is necessary to determine whether charging the energy storage device according to Pj2 will cause a second overload phenomenon in the substation. If a second overload phenomenon exists, it is necessary to re-plan the charging power of the energy storage device so that the energy storage device is charged according to the value of GFP2+BYQ*0.8-T2(k); if there is no second overload phenomenon, continue to charge according to Pj2.

[0098] Among them, the condition for judging whether there is a second overload phenomenon is: judging whether T2(k)+Pj2-GFP2 is greater than or equal to BYQ*0.75. If T2(k)+Pj2-GFP2≥BYQ*0.75, it is considered that there is a second overload phenomenon in the current substation, and it can be adjusted in advance to eliminate the second overload phenomenon; if T2(k)+Pj2-GFP2<BYQ*0.75, it is considered that there is no second overload phenomenon in the current substation, and no adjustment is required.

[0099] Among them, T2(k)+Pj2-GFP2 represents the total load in the current substation, that is, the apparent power of the current substation.

[0100] Regulation strategy at peak discharge state:

[0101] For the control strategy when the control state is the peak discharge state, please refer to Figure 5 In this state, the energy storage device mainly discharges, but it is necessary to always prevent the possible overload in the substation. At this time, photovoltaic power generation will generally occur. When photovoltaic power generation is returned, the energy storage device will selectively charge to ensure the income.

[0102] Specifically, Figure 5 is a flow chart of a control strategy when the regulation state of the energy storage device on the station side in a balanced state is a peak discharge state provided by an embodiment of the present invention, such as Figure 5 As shown, the third discharge power Pj3 of the energy storage device is planned, and the third discharge power Pj3 = (DCQ3-Prat*Q3) / T3.

[0103] Among them, DCQ3 represents the power of the energy storage device in the peak discharge state, and T3 represents the total duration of the peak discharge state.

[0104] After planning the third discharge power Pj3 of the energy storage device, it is necessary to determine whether the third discharge power Pj3 is equal to the rated discharge power PCSrat of the energy storage device. 放 In order to protect the energy storage device and reduce the damage rate of the energy storage device, the maximum discharge power of the energy storage device cannot exceed the rated discharge power PCSrat when discharging. 放 .

[0105] If Pj3 is greater than or equal to PCSrat 放 , then the energy storage device is based on PCSrat 放 Discharge, if Pj3 is less than PCSrat 放 , the energy storage device discharges according to Pj3.

[0106] Whether the energy storage device is discharged according to Pj3 or according to PCSrat 放 When discharging, it is necessary to determine whether the state of charge of the energy storage device has reached the first lower limit, that is, whether the SOC is less than or equal to 5%. If SOC≤5%, it means that the energy storage device has no electricity to discharge, and the energy storage device stops discharging and maintains the current state of charge. If SOC>5%, it means that the energy storage device has electricity to discharge. At this time, it is necessary to determine whether the current substation is in the first control state. If it is in the first control state, it means that the photovoltaic output is large, and it is necessary to continue to determine whether the photovoltaic output is returned. If it is not in the first control state, it means that the current apparent power of the substation is relatively high, and it is necessary to continue to determine whether the discharge of the energy storage device according to Pj3 will cause the third overload phenomenon in the substation.

[0107] Among them, the power control state is used to indicate that the energy flow of photovoltaic output is greater than or equal to the sum of the energy flow of the energy storage device and the energy flow of the current load in the area, indicating that photovoltaic power generation is relatively large. When the sum of the energy flow of the energy storage device and the energy flow of the current load in the area is greater than the energy flow of photovoltaic output, it is in the empty state, indicating that photovoltaic power generation is relatively small.

[0108] Among them, the condition for judging whether the current area is in the first control state is: judging whether T3(K)-Pj3-GFP3 is less than or equal to 0. If T3(K)-Pj3-GFP3≤0, it means that the current area is in the first control state. If T3(K)-Pj3-GFP3>0, it means that the current area is not in the first control state.

[0109] Among them, T3(K) represents the load of pure electricity load in the substation under the peak discharge state, GFP3 represents the power output of photovoltaic power in the substation under the peak discharge state. T3(K)-Pj3-GFP3 represents the total load in the current substation, that is, the apparent power of the current substation.

[0110] The condition for judging whether the photovoltaic has feedback is: judging whether T3(K)-GFP3 is greater than or equal to 0. If it is greater than or equal to 0, it means that the photovoltaic has no feedback; if it is less than 0, it means that the photovoltaic has feedback.

[0111] When T3(K)-GFP3=0, it means that the photovoltaic power generation just meets the power demand of the pure power load in the substation. When T3(K)-GFP3>0, it means that the power demand of the pure power load in the substation is not met. When T3(K)-GFP3≥0, the energy storage device needs to re-plan the discharge power, that is, let the energy storage device discharge according to the value of T3(K)-GFP3.

[0112] When T3(K)-GFP3<0, it means that the photovoltaic power generation has surplus power in addition to meeting the power demand of the pure power load in the substation area. The energy storage device can store the surplus power for discharge in the discharge stage.

[0113] When T3(K)-GFP3<0, before charging the energy storage device, it is necessary to first determine whether the current state of charge of the energy storage device has reached the upper limit of charging, that is, to determine whether the SOC of the energy storage device is greater than or equal to 95%. If SOC≥95%, it means that the upper limit has been reached, which means that the current energy storage device can no longer be charged. If the energy storage device is forced to continue charging, it will cause damage to the energy storage device and affect the service life of the energy storage device. Therefore, when the upper limit of charging is reached, the energy storage device stops charging and maintains the current state of charge. If SOC<95%, it means that the upper limit of charging has not been reached, and charging is performed according to the photovoltaic return power. Among them, the photovoltaic return power is the value of GFP3-T3(K).

[0114] When charging according to the photovoltaic return power, it is necessary to determine whether the photovoltaic return power exceeds the rated charging power PCSrat of the energy storage device. 充 In order to protect the energy storage device, the charging power of the energy storage device cannot exceed the rated charging power PCSrat 充 .

[0115] In GFP3-T3(K)≥PCSrat 充 When the photovoltaic return power exceeds the rated charging power of the energy storage device, the energy storage device will be charged according to PCSrat 充 Charging; in GFP3-T3(K)<PCSrat 充 When , it indicates that the photovoltaic return power does not exceed the rated charging power of the energy storage device, and the energy storage device is charged according to GFP3-T3(K).

[0116] When not in the first control state, the condition for judging whether the discharge of the energy storage device according to Pj3 will cause the third overload phenomenon in the substation is: judging whether T3(K)-GFP3-Pj3 is greater than or equal to BYQ*0.8. If T3(K)-GFP3-Pj3≥BYQ*0.8, it is considered that the photovoltaic power supply and the energy storage device jointly supply power according to the power of Pj3 under the peak discharge state cannot meet the load demand of the pure power load in the current substation, and the load demand exceeds the alarm threshold, causing the third overload phenomenon in the substation. Therefore, it is necessary to increase the discharge power of the energy storage device, that is, to re-plan the discharge power of the energy storage device to eliminate the third overload phenomenon.

[0117] If T3(K)-GFP3-Pj3<BYQ*0.8, it is considered that the photovoltaic power supply and energy storage equipment jointly supply power according to the power of Pj3 under the peak discharge state, which can meet the load demand of the pure power load in the current substation. Therefore, there is no need to readjust the discharge power of the energy storage equipment at this time, and the energy storage equipment continues to discharge according to Pj3.

[0118] When T3(K)-GFP3-Pj3≥BYQ*0.8, the discharge power of the energy storage device is replanned to allow the energy storage device to discharge according to the value of T3(K)-GFP3-BYQ*0.8.

[0119] When the energy storage device is discharged according to the value of T3(K)-GFP3-BYQ*0.8, it is necessary to determine whether this value is greater than or equal to the rated discharge power PCSrat of the energy storage device. 放 If T3(K)-GFP3-BYQ*0.8≥PCSrat 放 , it means that the rated discharge power of the energy storage device is exceeded. In order to protect the energy storage device and increase its service life, the energy storage device should be discharged at the rated power PCSrat 放 Discharge, if T3(K)-GFP3-BYQ*0.8<PCSrat 放 , it means that the rated discharge power PCSrat of the energy storage device has not been exceeded 放 , allowing the energy storage device to continue discharging according to the re-planned value of T3(K)-GFP3-BYQ*0.8.

[0120] Control strategy in peak discharge state:

[0121] For the control strategy when the control state is the peak discharge state, please refer to Figure 6 In this state, the energy storage device is mainly discharged, but it is necessary to always prevent the possible heavy overload phenomenon in the station area. The difference between this and the peak discharge state is that the charging conditions are more stringent. The discharge reserve is generally very small and basically less than the first lower limit. The energy storage device is discharged to the limit, that is, no reserve is made.

[0122] Specifically, Figure 6 is a flow chart of a control strategy when the regulation state of the energy storage device on the side of the station in a balanced state is a valley charging state provided by an embodiment of the present invention, such as Figure 6 As shown, the fourth discharge power Pj4 of the energy storage device is planned, and the fourth discharge power Pj4=(DCQ4-Prat*Q4) / T4.

[0123] Among them, DCQ4 represents the power of the energy storage device in the peak discharge state, and T4 represents the total duration of the peak discharge state.

[0124] After planning the fourth discharge power Pj4 of the energy storage device, it is necessary to determine whether the fourth discharge power Pj4 is equal to the rated discharge power PCSrat of the energy storage device. 放 In order to protect the energy storage device and reduce the damage rate of the energy storage device, the maximum discharge power of the energy storage device cannot exceed the rated discharge power PCSrat when discharging. 放 .

[0125] If Pj4 is greater than or equal to PCSrat 放 , then the energy storage device is based on PCSrat 放 Discharge, if Pj4 is less than PCSrat 放 , the energy storage device discharges according to Pj4.

[0126] Whether it is discharged according to Pj4 or according to PCSrat 放 , it is necessary to continue to determine whether the state of charge of the energy storage device has reached the first lower limit, that is, to determine whether the SOC is less than or equal to 5%. If SOC≤5%, it means that the energy storage device has no electricity to discharge, and the energy storage device stops discharging and maintains the current state of charge. If SOC>5%, it means that the energy storage device has electricity to discharge. At this time, it is necessary to determine whether the current area is in the second control state. If it is in the second control state, it means that the photovoltaic output is large, and it is necessary to continue to determine whether the photovoltaic output is returned. If it is not in the second control state, it means that the current apparent power of the area is relatively high, and it is necessary to continue to determine whether the discharge of the energy storage device according to Pj4 will cause the fifth overload phenomenon in the area.

[0127] Among them, the condition for judging whether the current area is in the second control state is: judging whether T4(K)-Pj4-GFP4 is less than or equal to 0. If T4(K)-Pj4-GFP4≤0, it means that the current area is in the control state. If T4(K)-Pj4-GFP4>0, it means that the current area is not in the control state.

[0128] Among them, T4(K) represents the load of pure electricity load in the substation under the peak discharge state, GFP4 represents the amount of photovoltaic output in the substation under the peak discharge state. T4(K)-Pj4-GFP4 represents the total load in the current substation, that is, the apparent power of the current substation.

[0129] The condition for judging whether the photovoltaic has a foldback is: judging whether T4(K)-GFP4 is greater than or equal to 0. If it is greater than or equal to 0, it means that the photovoltaic has no foldback; if it is less than 0, it means that the photovoltaic has a foldback.

[0130] When T4(K)-GFP4=0, it means that the photovoltaic power generation just meets the power demand of the pure power load in the substation. When T4(K)-GFP4>0, it means that the power demand of the pure power load in the substation is not met. When T4(K)-GFP4≥0, the energy storage device needs to re-plan the discharge power, that is, let the energy storage device discharge according to the value of T4(K)-GFP4.

[0131] When T4(K)-GFP4<0, it means that the photovoltaic power generation has surplus power in addition to meeting the power demand of the pure power load in the substation area. The energy storage device can store the surplus power for discharge in the discharge stage.

[0132] When T4(K)-GFP4<0, before charging the energy storage device, it is necessary to first determine whether the current state of charge of the energy storage device has reached the upper limit of charging, that is, to determine whether the SOC of the energy storage device is greater than or equal to 95%. If SOC≥95%, it means that the upper limit has been reached, which means that the current energy storage device can no longer be charged. If the energy storage device is forced to continue charging, it will cause damage to the energy storage device and affect the service life of the energy storage device. Therefore, when the upper limit of charging is reached, the energy storage device stops charging and maintains the current state of charge. If SOC<95%, it means that the upper limit of charging has not been reached, but whether the energy storage device can store the power output by photovoltaics needs to be further determined, that is, whether the conditions for absorbing the power returned by photovoltaics are met.

[0133] The condition for judging whether the amount of electricity returned by photovoltaic power is allowed to be absorbed is as follows: judging whether the value of GFP4-T4(K) is greater than the preset first rated charging power PCSrat1 充 And whether the SOC of the energy storage device is less than or equal to the preset state of charge, only when both conditions are met at the same time will the energy storage device be allowed to absorb the power returned by the photovoltaic power plant and charge according to the preset first rated charging power. If not met, the energy storage device stops charging and discharging and maintains the current state of charge.

[0134] Among them, the preset first rated charging power PCSrat1 充The value is less than the rated charging power PCSrat of the energy storage device 充 The value of the first rated charging power PCSrat1 充 The present invention does not specifically limit the setting of the value of PCSrat1. 充 The value is the rated charging power PCSrat of the energy storage device 充 For example, PCSrat1 充 =PCSrat1 充 *0.5.

[0135] The setting of the preset state of charge value is selected according to the actual situation, and the present invention does not make any special limitation on this. The following is an example of an exemplary description using the preset state of charge of 60%, that is, GFP4-T4(K)>PCSrat1 充 At the same time, the SOC must be ≤ 60% to allow the energy storage device to absorb the power returned by photovoltaic power.

[0136] When not in the generation control state, the condition for judging whether the discharge of the energy storage device according to Pj4 will cause the fifth level of overload in the substation is: judging whether T4(K)-GFP4-Pj4 is greater than or equal to BYQ*0.8. If T4(K)-GFP3-Pj4≥BYQ*0.8, it is considered that the photovoltaic power supply and the energy storage device jointly supply power according to the power of Pj4 in the peak discharge state cannot meet the load demand of the pure power load in the current substation, and the load demand exceeds the alarm threshold, causing the fifth level of overload in the substation. Therefore, it is necessary to increase the discharge power of the energy storage device, that is, to re-plan the discharge power of the energy storage device to eliminate the fifth level of overload.

[0137] If T4(K)-GFP4-Pj4<BYQ*0.8, it is considered that the photovoltaic power supply and energy storage equipment jointly supply power according to the power of Pj4 under the peak discharge state, which can meet the load demand of the pure power load in the current substation. Therefore, there is no need to readjust the discharge power of the energy storage equipment at this time, and the energy storage equipment continues to discharge according to Pj4.

[0138] When T4(K)-GFP4-Pj4≥BYQ*0.8, the discharge power of the energy storage device is replanned to allow the energy storage device to discharge according to the value of T4(K)-GFP4-BYQ*0.8.

[0139] When the energy storage device is discharged according to the value of T4(K)-GFP4-BYQ*0.8, it is necessary to determine whether the value is greater than or equal to the rated discharge power PCSrat of the energy storage device. 放 If T4(K)-GFP4-BYQ*0.8≥PCSrat 放, it means that the rated discharge power of the energy storage device is exceeded. In order to protect the energy storage device and increase its service life, the energy storage device should be discharged at the rated power PCSrat 放 Discharge, if T4(K)-GFP4-BYQ*0.8<PCSrat 放 , it means that the rated discharge power PCSrat of the energy storage device has not been exceeded 放 , allowing the energy storage device to continue discharging according to the re-planned value of T4(K)-GFP4-BYQ*0.8.

[0140] Regulation strategy for off-peak power state:

[0141] For the control strategy when the control state is the valley power backup state, you can refer to Figure 7 This state usually occurs in the middle of the day, and the energy storage device is charged. In this state, the energy storage device should be charged as much as possible, but it is necessary to always prevent the station from being overloaded due to charging.

[0142] It is understandable that both the low-valley reserve state and the first-valley reserve state are valley electricity price stages, and both require energy storage charging and reserve power. The low-valley reserve state generally occurs near the peak photovoltaic power generation at noon, and the load situation is more complicated than the first-valley reserve state that occurs late at night. Photovoltaic power may generate backflow, resulting in heavy overload in the substation, so it is necessary to prevent photovoltaic power from generating backflow and causing heavy overload in the substation.

[0143] Specifically, Figure 7 : is a flow chart of a control strategy when the regulation state of the energy storage device on the substation side in a balanced state is a valley power reserve state provided by an embodiment of the present invention, such as Figure 7 As shown, the fifth charging power Pj5 of the energy storage device is planned, and the fifth charging power Pj5 = (DCQ5-Prat*Q5) / T5.

[0144] Among them, DCQ5 represents the power of the energy storage device in the valley power backup state, and T5 represents the total duration of the valley power backup state.

[0145] After planning the fifth charging power Pj5 of the energy storage device, it is necessary to determine whether the fifth charging power Pj5 is equal to the rated charging power PCSrat of the energy storage device. 充 In order to protect the energy storage device and reduce the damage rate of the energy storage device, the maximum charging power of the energy storage device cannot exceed the rated charging power PCSrat when charging. 充 .

[0146] If Pj5 is greater than or equal to PCSrat 充 , then the energy storage device is based on PCSrat 充 Charging, if Pj5 is less than PCSrat 充, the energy storage device is charged according to Pj5.

[0147] Whether the energy storage device is charged according to Pj5 or PCSrat 充 When charging, it is necessary to determine whether the second peak regulation is needed. If the second peak regulation is needed, it is necessary to first determine whether the charge state of the energy storage device has reached the lower limit. If the second peak regulation is not needed, it is necessary to determine whether the charge state of the energy storage device is greater than the fifth reserved energy percentage. The fifth reserved energy percentage is Q5, which is the energy percentage reserved in the valley backup state.

[0148] Among them, the condition for judging whether the second peak adjustment is needed is: judging whether T5(K)-GFP5 is greater than or equal to BYQ*0.75. If T5(K)-GFP5 is greater than or equal to BYQ*0.75, it is considered that the second peak adjustment is needed; if T5(K)-GFP5 is less than BYQ*0.75, it is considered that the second peak adjustment is not needed.

[0149] Among them, T5(K) represents the pure power load in the substation under the peak maintenance state, GFP5 represents the photovoltaic output power in the substation under the valley backup state, and BYQ*0.75 represents 75% of the total capacity of the transformer, which is the safe load rate.

[0150] Determine whether the state of charge of the energy storage device has reached the preset second lower limit. If it has reached the preset second lower limit, it means that the energy storage device currently has no power to discharge and cannot be used for peak load regulation. The energy storage device maintains the current SOC and does not charge or discharge. If it has not reached the preset second lower limit, it means that the energy storage device currently has power to discharge and the discharge power of the energy storage device is re-planned. When the energy storage device discharges according to the re-planned discharge power, it is necessary to determine whether it is less than the rated discharge power PCSrat of the energy storage device. 放 If it is less than, the energy storage device discharges according to the re-planned discharge power of the energy storage device to achieve peak load regulation. If it is greater than or equal to, the energy storage device discharges according to the rated discharge power PCSrat 充 Discharge to achieve peak load regulation.

[0151] The preset second lower limit value is larger than the preset first lower limit value and can be set according to actual conditions. The present invention does not specifically limit this. The following explanation will be given by taking the preset second lower limit value of 20% as an example.

[0152] The condition for judging whether the state of charge of the energy storage device has reached the preset second lower limit is: whether the SOC of the energy storage device is less than or equal to 20%. If the SOC value is ≤20%, it is considered that the state of charge of the energy storage device has reached the lower limit. If the SOC value is greater than 20%, it is considered that the state of charge of the energy storage device has not reached the lower limit. When the SOC value is greater than 20%, the discharge power of the energy storage device is replanned to allow the energy storage device to discharge according to the value of T5(K)-GFP5-BYQ*0.75.

[0153] When peak load regulation is not possible, it is necessary to determine whether the state of charge of the energy storage device is greater than Q5. If the SOC of the energy storage device is greater than Q5, it means that the energy storage device currently has more energy. At this time, it is necessary to determine whether charging the energy storage device according to Pj5 will cause the current substation to be in the third control state; if the SOC of the energy storage device is less than Q5, it means that the energy storage device currently has less power. At this time, it is necessary to determine whether charging the energy storage device according to Pj5 will cause the substation to be in the sixth level of overload.

[0154] When SOC>Q5, the condition for judging whether the current area is in the third control state is: judging whether T5(K)+Pj5-GFP5 is less than or equal to 0. If T5(K)+Pj5-GFP5>0, it means that the energy storage device is charged according to Pj5 and does not put the current area in the third control state. In this case, the energy storage device does not charge or discharge and maintains the current state of charge.

[0155] If T5(K)+Pj5-GFP5≤0, it means that the energy storage device is charged according to Pj5, which will cause the substation to be in the third generation control state. It is necessary to increase the charging power of the energy storage device to eliminate the generation control state.

[0156] However, before increasing the charging power of the energy storage device, it is necessary to determine whether the energy storage device has reached the charging upper limit, that is, to determine whether the SOC of the energy storage device is greater than or equal to 95%. If SOC ≥ 95%, it is considered that the energy storage device has reached the charging upper limit, and the energy storage device can no longer absorb more photovoltaic power return. Therefore, in this case, the energy storage device maintains the current charge state and does not charge or discharge; if SOC < 95%, it is considered that the energy storage device has not reached the charging upper limit, and the energy storage device can continue to absorb photovoltaic power return.

[0157] When the energy storage device can continue to absorb the power returned by the photovoltaic power plant, it is necessary to re-plan the charging power of the energy storage device, that is, let the energy storage device charge according to the value of GFP5-T5(K). When the energy storage device is charged according to the value of GFP5-T5(K), it is necessary to first determine whether the value of GFP5-T5(K) is greater than or equal to the rated charging power PCSrat of the energy storage device. 充 If GFP5-T5(K)≥PCSrat 充, it means that the energy storage device exceeds the rated charging power PCSrat when charging according to the value of GFP5-T5(K) 充 In order to protect the energy storage device and increase its service life, the energy storage device is charged at rated power PCSrat 充 If GFP5-T5(K)<PCSrat 充 , it means that the energy storage device does not exceed the rated charging power PCSrat when charging according to the value of GFP5-T5(K) 充 , then in this case, the energy storage device continues to charge according to the value of GFP5-T5(K).

[0158] When SOC≤Q5, the condition for judging whether charging the energy storage device according to Pj5 will cause the sixth level of overload in the substation is: judging whether T5(K)+Pj5-GFP5 is greater than or equal to BYQ*0.8. When T5(K)+Pj5-GFP5≥BYQ*0.8, it indicates that charging the energy storage device according to Pj5 will cause the sixth level of overload in the substation. At this time, it is necessary to reduce the charging power of the energy storage device, that is, re-plan the charging power of the energy storage device so that the energy storage device can be charged according to the value of GFP5+BYQ*0.8-T5(K).

[0159] Among them, T5(K)+Pj5-GFP5 indicates the total load of the current substation, that is, the apparent power.

[0160] When T5(K)+Pj5-GFP5<BYQ*0.8, it indicates that charging the energy storage device according to Pj5 will not cause the sixth level of overload in the substation. At this time, the energy storage device can continue to charge according to the value of GFP5+BYQ*0.8-T5(K).

[0161] Control strategy of terminal discharge state:

[0162] For the control strategy when the control state is the terminal discharge state, please refer to Figure 8 In this state, the photovoltaic power generation basically does not work, and the power output of the photovoltaic power generation is basically 0. The function of the terminal discharge state is to clear the power stored in the energy storage device, lay the foundation for the next regulation cycle, and enable the energy storage device to be charged at the beginning of the next regulation cycle. In this process, it is necessary to prevent the possible heavy overload phenomenon in the substation at any time.

[0163] Specifically, Figure 8 is a flow chart of a control strategy when the regulation state of the energy storage device on the station side in a balanced state is a terminal discharge state provided by an embodiment of the present invention, such as Figure 8As shown, the sixth discharge power Pj6 of the energy storage device is planned, and the sixth discharge power Pj6 = (DCQ6-Prat*Q6) / T6.

[0164] Among them, DCQ6 represents the power of the energy storage device in the terminal discharge state, and T6 represents the total duration of the terminal discharge state.

[0165] After planning the sixth discharge power Pj6 of the energy storage device, it is necessary to determine whether the sixth discharge power Pj6 is equal to the rated discharge power PCSrat of the energy storage device. 放 In order to protect the energy storage device and reduce the damage rate of the energy storage device, the maximum discharge power of the energy storage device cannot exceed the rated discharge power PCSrat when discharging. 放 .

[0166] If Pj6 is greater than or equal to PCSrat 放 , then the energy storage device is based on PCSrat 放 Discharge, if Pj6 is less than PCSrat 放 , the energy storage device discharges according to Pj6.

[0167] Whether the energy storage device is discharged according to Pj6 or PCSrat 放 When discharging, it is necessary to determine whether the state of charge of the energy storage device has reached the lower limit, that is, to determine whether the SOC is less than or equal to 5%. When SOC≤5%, it means that the energy storage device has no electricity to discharge, so the energy storage device stops discharging and maintains the current state of charge. When SOC>5%, it means that the energy storage device has electricity to discharge, so the energy storage device is discharged according to Pj6.

[0168] When SOC>5%, when the energy storage device discharges according to Pj6, it is necessary to determine whether the control method will cause the fourth overload phenomenon in the substation. If the fourth overload phenomenon occurs, it is necessary to re-plan the discharge power of the energy storage device. If the fourth overload phenomenon does not occur, it is necessary to determine whether the current substation is overloaded.

[0169] Among them, the condition for judging whether the fourth overload phenomenon will occur in the substation is: judging whether T6(K)-Pj6-GFP6 is greater than or equal to BYQ*0.8. When T6(K)-Pj6-GFP6≥BYQ*0.8, it is considered that when the energy storage device discharges according to Pj6, it will cause the fourth overload phenomenon in the substation. At this time, it is necessary to increase the discharge power of the energy storage device, that is, re-plan the discharge power of the energy storage device to eliminate the fourth overload phenomenon. At this time, the energy storage device is discharged according to the value of T6(K)-BYQ*0.8-GFP6.

[0170] Among them, T6(K) represents the load of the pure power load in the substation under the terminal discharge state, GFP6 represents the power output of the photovoltaic power in the substation under the terminal discharge state. T6(K)-Pj6-GFP6 represents the total load in the current substation, that is, the apparent power of the current substation.

[0171] When T6(K)-Pj6-GFP6≥BYQ*0.8, when the energy storage device discharges according to the value of T6(K)-BYQ*0.8-GFP6, it is necessary to determine whether this value exceeds the rated discharge power PCSrat of the energy storage device. 放 .

[0172] In T6(K)-BYQ*0.8-GFP6≥PCSrat 放 When the rated discharge power PCSrat of the energy storage device is exceeded 放 In order to protect the energy storage device, the energy storage device discharges at rated power PCSrat 放 Discharge.

[0173] In T6(K)-BYQ*0.8-GFP6<PCSrat 放 When the rated discharge power PCSrat of the energy storage device is not exceeded 放 At this time, the energy storage device can be discharged according to T6(K)-BYQ*0.8-GFP6.

[0174] When T6(K)-Pj6-GFP6<BYQ*0.8, it is considered that when the energy storage device discharges according to Pj6, it will not cause the fourth level of overload in the substation. At this time, it is necessary to determine whether the current substation meets the overload condition, that is, whether T6(K)-Pj6-GFP6 is greater than or equal to 0. If T6(K)-Pj6-GFP6≥0, it is considered that when the energy storage device discharges according to Pj6, it will cause the current substation to be overloaded. At this time, it is necessary to reduce the discharge power of the energy storage device, that is, re-plan the discharge power of the energy storage device to eliminate the overload phenomenon and allow the energy storage device to discharge according to the value of T6(K)-GFP6. If T6(K)-Pj6-GFP6<0, it is considered that when the energy storage device discharges according to Pj6, it will not cause the current substation to be overloaded. At this time, the energy storage device continues to discharge according to Pj6.

[0175] A method for regulating an energy storage device on the side of a substation in a balanced state is provided in an embodiment of the present invention. First, the regulation state of the energy storage device on the side of the substation is divided into at least a first valley standby state, a flat peak holding state, a peak discharge state and a final discharge state according to the local peak-valley electricity price policy; the first valley standby state is the first valley electricity price period in a day when photovoltaic power is not in use, the flat peak holding state is the flat peak electricity price period in a day, the peak discharge state is the peak electricity price period in a day, and the final discharge state is the non-valley electricity price period in a day when photovoltaic power is not in use in the substation; then, in the first valley standby state and the flat peak holding state, the charging power of the energy storage device is planned according to the amount of electricity that the energy storage device needs to reserve at the end of the corresponding period and the duration of the corresponding period; in the peak discharge state, the discharge power of the energy storage device is planned according to the amount of electricity that the energy storage device needs to reserve at the end of the corresponding period and the duration of the corresponding period; in the final discharge state, the discharge power of the energy storage device is planned according to the amount of electricity in the energy storage device when entering the final discharge state and the duration of the corresponding period, so that the amount of electricity of the energy storage device reaches the first discharge lower limit at the end of the final discharge state. Since the charging and discharging power of the energy storage device can be planned based on the amount of electricity that needs to be reserved by the energy storage device at the end of the corresponding time period and the length of the corresponding time period, the control strategy is simple and can reduce costs compared to the existing technology. In addition, because the inherent characteristics of the energy storage device can be fully utilized, the energy storage device can be charged as much as possible when the electricity price is low, and discharged as much as possible when the price is high, so as to maximize the benefits. In each control strategy, it will also be considered whether the load rate of the current substation exceeds the heavy overload load rate of the transformer, that is, it will be considered whether there is a heavy overload phenomenon in the current substation. When there is a heavy overload phenomenon, adjustments will be made to dynamically maintain the balance between the substation and the power grid, thereby increasing the service life of the transformer and the stability of the power grid system operation.

[0176] An embodiment of a fusion IoT terminal:

[0177] Regarding an embodiment of a fusion IoT terminal provided in an embodiment of the present invention, reference may be made to the relevant description of the fusion IoT terminal in the embodiment of the control method of the energy storage device on the substation side in a balanced state, which will not be repeated here.

[0178] The fusion IoT terminal provided in the embodiment of the present invention can achieve the same beneficial effects as the control method of the energy storage device on the substation side in the aforementioned equilibrium state, which will not be repeated here.

Claims

1. A method for regulating an energy storage device at a station side in a balanced state, characterized in that: include: According to the local peak-valley electricity price policy, the regulation state of the energy storage equipment on the substation side is divided into at least the first valley backup state, the flat peak holding state, the peak discharge state and the final discharge state; The first valley reserve state is the first valley electricity price period in a day when photovoltaic power is not in use, the flat peak holding state is the flat peak electricity price period in a day, the peak discharge state is the peak electricity price period in a day, and the final discharge state is the non-valley electricity price period in a day when photovoltaic power is not in use; In the first valley power reserve state and the flat peak holding state, the charging power of the energy storage device is planned according to the amount of power that the energy storage device needs to reserve at the end of the corresponding time period and the duration of the corresponding time period; In the peak discharge state, the discharge power of the energy storage device is planned according to the amount of electricity that the energy storage device needs to reserve at the end of the corresponding time period and the duration of the corresponding time period; In the final discharge state, the discharge power of the energy storage device is planned according to the amount of electricity in the energy storage device when entering the final discharge state and the duration of the corresponding time period, so that the amount of electricity in the energy storage device reaches the first discharge lower limit when the final discharge state ends.

2. The control method of the energy storage device at the station side in the equilibrium state according to claim 1 is characterized in that: The peak leveling holding state further includes: when the first peak regulation is required, allowing the energy storage device to discharge according to the first peak regulation discharge power; Among them, the first peak-shaving discharge power is the value obtained by deducting the load of the pure power load in the substation under the flat peak maintenance state from the photovoltaic output power in the substation under the flat peak maintenance state and then deducting the safe load rate of the transformer.

3. The control method of the energy storage device at the station side in a balanced state according to claim 1, characterized in that: Also includes: Peak discharge state and valley standby state; The peak discharge state is the peak electricity price period in a day, and the valley power reserve state is the other valley electricity price period in a day; In the peak discharge state, the discharge power of the energy storage device is planned according to the amount of electricity that the energy storage device needs to reserve at the end of the corresponding time period and the duration of the corresponding time period; In the valley power backup state, the charging power of the energy storage device is planned according to the amount of electricity that needs to be reserved by the energy storage device at the end of the corresponding time period and the duration of the corresponding time period; The valley power reserve state further includes: when the energy storage device is charged according to the fifth charging power in the valley power reserve state, it is also determined whether a second peak load regulation is required, and when the second peak load regulation is required, the energy storage device is discharged according to the second peak load regulation discharge power; Among them, the second peak-shaving discharge power is the value obtained by deducting the load of the pure power load in the substation under the valley backup power state from the photovoltaic output power in the substation under the valley backup power state and then deducting the safety load rate of the transformer.

4. The control method of the energy storage device at the station side in the equilibrium state according to claim 2 is characterized in that: In the first valley backup state, if there is a first overload phenomenon, the energy storage device is charged according to the overload rate of the transformer minus the load of the pure power load of the substation in the first valley backup state and then minus the value of the photovoltaic output power in the substation in the first valley backup state; In the flat peak holding state, if there is a second overload phenomenon, the energy storage device is charged according to the value of the photovoltaic output power in the area under the flat peak holding state plus the overload rate of the transformer minus the load value of the pure power load in the area under the flat peak holding state; The safety load rate is smaller than the overload load rate.

5. The control method of the energy storage device at the station side in a balanced state according to claim 1, characterized in that: In the peak discharge state, if it is in the first control state and the photovoltaic power in the current area is not fed back, the energy storage device is discharged according to the difference between the load of the pure power load in the area under the peak discharge state and the power output of the photovoltaic power in the area under the peak discharge state; when the photovoltaic power in the current area is fed back, the energy storage device is charged according to the photovoltaic fed back power; The photovoltaic return power is the difference between the photovoltaic output power in the area under the peak discharge state and the load of the pure power load in the area under the peak discharge state; If it is not in the first control state and there is a third overload phenomenon, the energy storage device is discharged according to the load of the pure power load in the area under the peak discharge state minus the photovoltaic output power in the area under the peak discharge state minus the overload rate of the transformer.

6. The control method of the energy storage device at the station side in a balanced state according to claim 1, characterized in that: In the terminal discharge state, if there is a fourth overload phenomenon, the energy storage device is discharged according to the load of the pure power load in the station area in the terminal discharge state minus the overload rate of the transformer and then minus the value of the photovoltaic output power in the station area in the final discharge state; If the fourth overload phenomenon does not exist and the overload condition is met, the energy storage device is discharged according to the difference between the load of the pure power load in the station area under the terminal discharge state and the photovoltaic output power in the station area under the final discharge state.

7. The control method of the energy storage device at the station side in a balanced state according to claim 3, characterized in that: In the peak discharge state, if it is in the second control state and the photovoltaic power in the current area is not fed back, the energy storage device is allowed to discharge according to the difference between the load of the pure power load in the area under the peak discharge state and the power output of the photovoltaic power in the area under the peak discharge state; If the photovoltaic power in the current area is fed back and the conditions for absorbing the photovoltaic fed back discharge amount are met, the energy storage device is charged according to the preset first rated charging power; When not in the second control state, if there is a fifth overload phenomenon, the energy storage device is discharged according to the load of the pure power load in the area under the peak discharge state minus the photovoltaic output power in the area under the peak discharge state minus the overload rate of the transformer; In the valley power reserve state, when the second peak regulation is not required and the energy storage device is in the third generation control state, the energy storage device is charged according to the difference between the photovoltaic output power in the station area under the valley power reserve state and the load of the pure power load in the station area under the valley power reserve state; If the second peak regulation is not required and the sixth overload phenomenon exists, the energy storage device is charged according to the value of the photovoltaic output power in the substation under the valley backup state plus the overload rate of the transformer minus the load value of the pure power load in the substation under the valley backup state; The safety load rate is smaller than the overload load rate.

8. The method for controlling the energy storage device at the station side in a balanced state according to claim 6, characterized in that: In the final discharge state, if the value of the load of the pure power load in the station area under the final discharge state minus the sixth discharge power under the final discharge state minus the photovoltaic output power in the station area under the final discharge state is greater than 0, it is considered that the overload condition is met.

9. The method for controlling the energy storage device at the station side in a balanced state according to claim 7, characterized in that: In the peak discharge state, if the value of the photovoltaic output power in the station area under the peak discharge state minus the load of the pure power load in the station area under the peak discharge state is greater than the preset first rated charging power and the charge state of the energy storage device is less than or equal to the preset charge state, it is considered that the conditions for allowing the absorption of photovoltaic return discharge are met; Among them, the preset first rated charging power is less than the rated charging power; and the preset state of charge is less than the charging upper limit.

10. A converged IoT terminal, comprising a centralized controller, characterized in that: The centralized controller is used to execute the control method of the energy storage equipment on the substation side in the equilibrium state as described in any one of 1-9 above.

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