Regulation and control method of transformer area heavy load and fusion Internet of Things terminal

Abstract

The invention relates to a zone area heavy load regulation and control method and a fusion Internet of Things terminal, and belongs to the field of new energy. The regulation and control method comprises the following steps: judging whether a current transformer area is heavy-loaded or not, when the current transformer area is forward heavy-loaded, enabling energy storage equipment in a charging state in the current transformer area to stop charging, then calculating first apparent power of the adjusted current transformer area, and judging whether the load rate of the current transformer area reaches a regulation and control target or not according to the first apparent power; if the regulation and control target is reached, the regulation and control are ended; and if the regulation and control target is not reached, enabling the energy storage equipment in the transformer area to discharge according to a value less than or equal to the rated discharge power. According to the invention, the occurrence of over-regulation caused by excessive discharge under the condition of forward heavy load can be reduced, and meanwhile, the service life of energy storage equipment can be prolonged.

Description

Technical Field

[0001] The invention relates to a method for regulating overload in a substation and a fusion Internet of Things terminal, and belongs to the field of new energy. Background Art

[0002] Against the backdrop of the goals of “carbon peak and carbon neutrality” and the wave of new power system construction, non-traditional loads such as photovoltaics and charging piles have poured in in large numbers, and power quality and power balance issues have become increasingly prominent. Transformer overloads still occur from time to time in some local areas. When the amount of electricity transmitted by the power grid to the substation is greater than the preset capacity of the transformer, it is called forward overload. When the photovoltaic output capacity in the substation is relatively high, electricity will be transmitted to the power grid. When the amount of electricity transmitted by photovoltaics to the power grid is greater than the preset capacity of the transformer, it is called reverse overload. If the overload phenomenon occurs and is not handled, the transformer will begin to heat up over time, affecting the service life of the transformer, and at the same time affecting the stability and reliability of the power system operation. Therefore, when overload occurs in the substation, regulation is required to eliminate the overload phenomenon.

[0003] The Chinese invention patent application with application publication number CN117691754A discloses an intelligent automatic control method, system and electronic device for the edge of the substation layer photovoltaic storage and charging resources. This method considers starting from the end side, selecting the load rate of the substation transformer as the key decision indicator for the output of the control command, and judging the current operating status of the substation by real-time monitoring the apparent power, reactive power and active power of the substation transformer, and calculating the load rate of the substation according to the current operating status of the substation using the corresponding formula, and then accurately judging whether there is a control demand for the substation according to the load rate, and when an overload event occurs, generating the optimal control command according to the type of overload event, so as to realize the precise control of distributed photovoltaics. Among them, in the case of a forward heavy overload, the energy storage device in the charging state will be forced to change to the discharge state, and discharge at the rated discharge power. This control strategy is prone to excessive discharge and there is a risk of over-control. Summary of the invention

[0004] The purpose of the present invention is to provide a method for regulating overload in a substation and a fusion Internet of Things terminal, so as to solve the problem in the prior art that excessive discharge is prone to occur under forward overload conditions, resulting in the risk of over-regulation.

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

[0006] A method for regulating overload in a substation of the present invention comprises the following steps: determining whether the current substation is overloaded, and when the current substation is positively overloaded, stopping charging of energy storage devices in the current substation that are in a charging state, and then calculating the adjusted first apparent power of the current substation, and determining whether the load rate of the current substation reaches a regulation target based on the first apparent power; if the regulation target is reached, terminating the regulation; if the regulation target is not reached, allowing the energy storage devices in the substation to discharge at a value less than or equal to the rated discharge power.

[0007] Furthermore, when the forward load rate of the substation is greater than the preset heavy load rate of the substation transformer, it is determined that the current substation is forward overloaded; the heavy load rate is greater than the control target.

[0008] Furthermore, the first apparent power is the value obtained by subtracting the power output of the photovoltaic power supply in the area at the corresponding time from the load of the pure power load in the area at the corresponding time and then subtracting the discharge power of the energy storage device in the discharge state in the area at the corresponding time.

[0009] Furthermore, after the energy storage device in the substation is discharged at a value less than or equal to the rated discharge power, the adjusted second apparent power of the current substation is calculated, and it is determined whether the load rate of the current substation reaches the control target according to the second apparent power; if the control target is reached, the control is terminated;

[0010] If the control target is not reached, the load of the adjustable equipment in the current area is adjusted, and the adjusted third apparent power of the current area is calculated until the load rate of the current area reaches the control target and the control is terminated.

[0011] Furthermore, when the current substation is reversely overloaded, the energy storage device in the discharging state in the current substation stops discharging, and then the adjusted fourth apparent power of the current substation is calculated, and it is judged whether the load rate of the current substation reaches the regulation target according to the fourth apparent power; if the regulation target is reached, the regulation is terminated; if the regulation target is not reached, the energy storage device in the substation is charged at a value less than or equal to the rated charging power.

[0012] Furthermore, when the reverse load rate of the substation is greater than the preset heavy load rate of the substation transformer, it is determined that the current substation is reversely overloaded; the heavy load rate is greater than the control target.

[0013] Furthermore, the fourth apparent power is the value obtained by subtracting the load of the pure power load of the area at the corresponding time from the photovoltaic output power of the area at the corresponding time, and then subtracting the charging power of the energy storage device in the charging state in the area at the corresponding time.

[0014] Furthermore, after charging the energy storage device in the substation at a value less than or equal to the rated charging power, the adjusted fifth apparent power of the current substation is calculated, and it is determined whether the load rate of the current substation reaches the control target according to the fifth apparent power; if the control target is reached, the control is terminated;

[0015] If the control target is not reached, the photovoltaic output power of the current area is limited, and the adjusted sixth apparent power of the current area is calculated until the load rate of the current area reaches the control target and the control is terminated.

[0016] A fusion IoT terminal of the present invention includes a centralized controller, and the centralized controller is used to execute the aforementioned control method for overloading of a substation.

[0017] The beneficial effects of the present invention are as follows: as an improved invention, the present invention first pauses the energy storage device in the charging state when a positive overload phenomenon occurs, and then calculates the apparent power of the current area to determine whether the apparent power of the current area is less than or equal to the safe load rate. If it is less than or equal to, the regulation is terminated, which can reduce the occurrence of over-regulation caused by excessive discharge; if it is greater than, then the energy storage device in the area starts to discharge at a value less than or equal to the rated discharge power, which can reduce damage to the energy storage device and thus increase the service life of the energy storage device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a flow chart of a method for regulating overload of a substation provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] 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.

[0020] In a photovoltaic power station, when the load demand of the station is too high, the amount of electricity output by photovoltaic power is not enough to meet the load demand of the current station, and the power grid needs to deliver electricity to the station. When the amount of electricity delivered by the power grid to the station is greater than the preset capacity of the transformer, the station will experience positive overload. Positive overload often occurs in the station. In order to solve the problem of over-regulation when adjusting the charging and discharging of the energy storage equipment in the station when positive overload occurs, the present invention is conceived to determine whether the positive overload exists in the current station by judging whether the positive load rate of the current station is greater than the preset overload rate of the station transformer. When it is greater than the preset overload rate, it means that there is a positive overload in the current station. In order to prevent excessive discharge and cause over-regulation, the energy storage equipment in the current station that is in a charging state can be stopped from charging first, and then the adjustment can be calculated. The first apparent power of the current substation is then determined, and then whether the load rate of the current substation reaches the control target is determined based on the first apparent power. If the control target is reached, it means that the forward overload phenomenon can be eliminated by simply stopping the charging of the energy storage device in the charging state, and the control can be ended; if the control target is not reached, it means that the forward overload phenomenon cannot be eliminated by simply stopping the charging of the energy storage device in the charging state. In order to eliminate the forward overload phenomenon, the energy storage device in the substation can be started to discharge, and the energy storage device can be discharged at a value less than or equal to the rated discharge power to eliminate the forward overload phenomenon.

[0021] An embodiment of a method for regulating overload of a station area:

[0022] The method of the present invention is implemented on a fusion IoT terminal.

[0023] 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.

[0024] The fusion IoT terminal includes a centralized controller, which is responsible for executing a method for controlling overload of a station area according to the present invention. Specifically, reference can be made to Figure 1 .

[0025] Figure 1FIG. 1 is a flow chart of a method for controlling overload of a station area provided by an embodiment of the present invention. Figure 1 As shown, first, it is necessary to identify whether the current station area is forward loaded or reverse loaded.

[0026] Specifically, first determine whether the current substation is overloaded. The current substation overload is divided into forward overload and reverse overload. The forward load rate of the current substation can be calculated. When the forward load rate is greater than or equal to the overload load rate of the transformer, the current substation is considered to be forward overloaded; calculate the reverse load rate of the current substation. When the reverse load rate is greater than or equal to the overload load rate of the transformer, the current substation is considered to be reverse overloaded.

[0027] Among them, positive overload can be represented by "1", also known as the super-use state, and reverse overload can be represented by "2", also known as the super-issue state.

[0028] One side of the transformer is the grid, and the other side of the transformer is the substation. When the amount of electricity transmitted from the grid to the substation is greater than or equal to the preset alarm capacity of the substation transformer, it is called overuse (also known as forward overload). When the photovoltaic output capacity in the substation is relatively high, electricity will be transmitted to the grid. When the amount of electricity transmitted from photovoltaic to the grid is greater than or equal to the preset alarm capacity of the substation transformer, it is called overgeneration (also known as reverse overload).

[0029] The acquisition of the heavy load rate of the transformer can be set based on statistics of historical data, or it can be stored in the fusion IoT terminal in advance for subsequent call, etc. The present invention does not make any special limitation on this. The present invention does not make any special limitation on the setting of the heavy load rate of the transformer, and the heavy load rate of 85% is taken as an example for exemplary description.

[0030] In order to reduce the number of adjustments, a margin will be set. At the end of each adjustment, the load rate of the current substation will be less than or equal to the difference between the heavy load rate and the margin. The setting of the margin can be set according to the actual situation. The present invention does not make any special restrictions on this. The following takes the margin of 10% as an example for exemplary explanation. That is, after the regulation is completed, the load rate of the current substation will be less than or equal to 75%. When the load rate of the current substation is less than or equal to 75%, it is considered that the substation and the power grid are in a balanced state and the regulation target is achieved. That is, when the forward overload is in progress, through regulation, when the forward load rate of the current substation is ≤75%, it is considered that the regulation target is achieved. When the reverse overload is in progress, through regulation, when the reverse load rate of the current substation is ≤75%, it is considered that the regulation target is achieved.

[0031] If it is positive overload, it means that there are too many electrical equipment in the substation, the power grid needs to transmit a large amount of electric energy to the substation, and the current forward load rate of the substation is greater than or equal to 85%, the transformer will heat up, and there will be danger. Therefore, it is necessary to use the positive overload control method to make the current forward load rate of the substation ≤75%. Among them, electrical equipment includes pure electrical loads and energy storage equipment in a charging state.

[0032] When a forward overload occurs, the control method is to force the energy storage equipment in the charging state in the substation to stop, and then calculate the first apparent power of the adjusted substation.

[0033] The energy storage devices in the photovoltaic storage area include those that are being charged, those that are being discharged, and those that are neither charged nor discharged. By forcibly stopping the energy storage devices that are in the charging state, the electrical equipment in the area can be initially reduced, thereby reducing the load demand in the area.

[0034] After the energy storage device in the charging state is forced to stop, it is necessary to calculate the first apparent power of the adjusted substation, and judge whether the current substation load rate reaches the control target based on the first apparent power; if the control target is reached, the control is ended; if the control target is not reached, the energy storage device in the substation is allowed to discharge at a value less than or equal to the rated discharge power.

[0035] When the energy storage equipment in the substation is charged at a value less than or equal to the rated discharge power, the energy storage equipment is no longer an electrical device, but is transformed into a discharge device, which can reduce the load demand of the substation.

[0036] The first apparent power is the load T1 of the pure power load in the corresponding area at the time minus the photovoltaic output power GFP1 of the corresponding area at the time minus the discharge power Pj of the energy storage device in the discharge state in the corresponding area at the time. 放 The value of the first apparent power = T1-GFP1-Pj 放 When a positive overload occurs, the corresponding time refers to the time after the energy storage device in the charging state is suspended when the positive overload occurs.

[0037] Among them, the discharge power Pj 放 It is the sum of the discharge powers of all energy storage devices in the discharge state.

[0038] If the control target is reached, the control is terminated, which means that the control target can be achieved by simply stopping the energy storage device in the charging state and allowing the energy storage device in the discharging state to continue discharging at the original discharge power. There is no need to increase the discharge power additionally, so the occurrence of over-control can be reduced.

[0039] If the control target is not reached, it is necessary to increase the power supply capacity of the power supply equipment. Because the current photovoltaic power has reached the output limit, it is necessary to rely on energy storage equipment to make the load rate of the current area reach the control target. Therefore, the state of charge (SOC) of each energy storage device in the current area can be detected first, and the discharge power of the energy storage device in the current area can be slowly increased, in the hope of using the least amount of electricity to eliminate the forward overload phenomenon, that is, to maximize the goal of supporting the power demand of the area with energy storage equipment. Specifically, the energy storage device with a relatively low SOC can be discharged according to the first power, and the energy storage device with a relatively high SOC can be discharged first according to a value greater than the first power but smaller than the rated discharge power, and then slowly increased until it is discharged according to the rated discharge power. Among them, the first power is less than the rated discharge power.

[0040] By allowing the energy storage devices in the substation to discharge at a power less than or equal to the rated discharge power, the load demand of the substation can be further reduced. At the same time, because the SOC of the energy storage device is taken into consideration, allowing each energy storage device to discharge at a power suitable for itself can reduce damage to the energy storage device and increase its service life.

[0041] In order to further improve the service life of the transformer, after the energy storage device in the substation is discharged at a power less than or equal to the rated discharge power, it is necessary to continue to calculate the adjusted second apparent power of the current substation, and judge whether the load rate of the current substation reaches the control target based on the second apparent power; if the control target is reached, the control is terminated; if the control target is not reached, the load of the adjustable equipment in the current substation is adjusted, and the adjusted third apparent power of the current substation is calculated, until the load rate of the current substation reaches the control target and the control is terminated.

[0042] The present invention does not specifically limit the type of adjustable load device, and the following takes the adjustable device as a charging pile as an example for exemplary description. Adjusting the load of the charging pile means adjusting the load demand of the charging pile, that is, adjusting the charging power of the charging pile, so that the charging pile is charged at a smaller charging power until the control target is reached.

[0043] Each time the load of the adjustable equipment in the substation is adjusted, the apparent power of the substation is calculated and then compared with the control target, ensuring that the control target can be achieved with as little discharge as possible, thereby reducing the occurrence of over-control.

[0044] If it is reverse overload, it means that the photovoltaic output in the substation is strong, photovoltaics generate feedback, and transmit electricity to the grid, and the reverse load rate of the current substation is greater than or equal to 85%. The transformer will heat up and there will be danger. Therefore, it is necessary to use the reverse overload control method to make the reverse load rate of the current substation ≤75%.

[0045] When reverse overload occurs, the control method is: force the energy storage equipment in the discharge state to stop, and then calculate the fourth apparent power of the adjusted substation.

[0046] By forcibly stopping the energy storage equipment in the discharge state in the substation, the load demand of the substation can be initially increased. After the energy storage equipment in the discharge state is forcibly stopped, it is necessary to calculate the fourth apparent power of the adjusted substation, and judge whether the current substation load rate reaches the control target according to the fourth apparent power; if the control target is reached, the control is terminated; if the control target is not reached, the energy storage equipment in the substation is charged at a value less than or equal to the rated charging power.

[0047] When the energy storage equipment in the substation is charged at a value less than or equal to the rated charging power, the energy storage equipment is no longer a discharging device, but is transformed into an electricity-consuming device that can absorb the return of photovoltaics to reduce the output of photovoltaic electricity to the grid.

[0048] The fourth apparent power is the photovoltaic output power GFP2 of the corresponding time zone minus the load T2 of the pure power load of the corresponding time zone minus the charging power Pj of the energy storage device in the charging state in the corresponding time zone. 充 That is, the fourth apparent power = GFP2-T2-Pj 充 When a reverse heavy load occurs, the corresponding time refers to the time after the energy storage device in the discharge state is suspended when the reverse heavy load occurs.

[0049] Among them, the charging power Pj 充 It is the sum of the discharge powers of all energy storage devices in a charging state.

[0050] If the control target is reached, the control is terminated, which means that the control target can be achieved by simply stopping the energy storage device in the discharge state and allowing the energy storage device in the charging state to continue discharging at the original discharge power. There is no need to increase the charging power additionally, so the occurrence of over-control can be reduced.

[0051] If the control target is not achieved, it is necessary to increase the charging power of the energy storage device to further absorb the photovoltaic return and reduce the photovoltaic power output to the grid. Therefore, the SOC of each energy storage device in the current area can be detected first, and the charging power of the energy storage device in the current area can be slowly increased in the hope that the energy storage device can maximize the power output of photovoltaics. Specifically, the energy storage device with a relatively high SOC can be charged at the second power, and the energy storage device with a relatively low SOC can be charged at a value greater than the second power but less than the rated charging power, and then slowly increased until it is charged at the rated charging power. Among them, the second power is less than the rated charging power.

[0052] By charging the energy storage devices in the substation at a power less than or equal to the rated charging power, the amount of electricity absorbed by photovoltaic output can be further increased and the amount of electricity output from photovoltaic to the grid can be reduced. At the same time, because the SOC of the energy storage device is taken into consideration, each energy storage device can be charged at a power suitable for itself, which can reduce damage to the energy storage device and increase its service life.

[0053] In order to further improve the service life of the transformer, after the energy storage equipment in the substation is charged at a power less than or equal to the rated charging power, it is necessary to continue to calculate the adjusted fifth apparent power of the current substation, and judge whether the load rate of the current substation reaches the control target based on the fifth apparent power; if the control target is reached, the control is terminated; if the control target is not reached, the photovoltaic output power of the current substation is limited, and the adjusted sixth apparent power of the current substation is calculated, until the load rate of the current substation reaches the control target and the control is terminated.

[0054] Each time the photovoltaic output of the current substation is adjusted, the apparent power of the substation is calculated and then compared with the control target, ensuring that the control target can be achieved with as little charging as possible, thereby reducing the occurrence of over-control.

[0055] An embodiment of the present invention provides a method for regulating overload in a substation. When a forward overload phenomenon occurs, the energy storage device in the charging state is first paused, and then the apparent power of the current substation is calculated to determine whether the apparent power of the current substation is less than or equal to the safe load rate. If it is less than or equal to, the regulation is terminated, which can reduce the occurrence of over-regulation caused by excessive discharge; if it is greater, the energy storage device in the substation is then allowed to start discharging at a value less than or equal to the rated discharge power, which can reduce the damage to the energy storage device, thereby increasing the service life of the energy storage device. Similarly, when a reverse overload phenomenon occurs, the energy storage device in the discharging state is first paused, and then the apparent power of the current substation is calculated to determine whether the apparent power of the current substation is less than or equal to the safe load rate. If it is less than or equal to, the regulation is terminated, which can reduce the occurrence of over-regulation caused by excessive charging; if it is greater, the energy storage device in the substation is then allowed to start charging at a value less than or equal to the rated charging power, which can reduce the damage to the energy storage device, thereby increasing the service life of the energy storage device.

[0056] An embodiment of a fusion IoT terminal:

[0057] Regarding an embodiment of a fusion IoT terminal provided in an embodiment of the present invention, reference may be made to the relevant description about the fusion IoT terminal in the embodiment of the aforementioned method for regulating overload in a station area, which will not be repeated here.

[0058] The integrated IoT terminal provided in the embodiment of the present invention can achieve the same beneficial effects as the aforementioned method for regulating overload in a substation, which will not be described in detail here.

Claims

1. A method for regulating overload in a station area, characterized in that: The method comprises the following steps: determining whether the current substation is overloaded, and when the current substation is positively overloaded, stopping charging of energy storage devices in the current substation that are in a charging state, and then calculating the adjusted first apparent power of the current substation, and determining whether the load rate of the current substation reaches a control target according to the first apparent power; if the control target is reached, terminating the control; if the control target is not reached, allowing the energy storage devices in the substation to discharge at a value less than or equal to the rated discharge power.

2. The method for controlling overload in a station area according to claim 1, characterized in that: When the forward load rate of the substation is greater than the preset heavy load rate of the substation transformer, it is determined that the current substation is forward overloaded; the heavy load rate is greater than the control target.

3. The method for controlling overload in a station area according to claim 1, characterized in that: The first apparent power is a value obtained by subtracting the power output of the photovoltaic power plant in the area at the corresponding time from the load of the pure power load in the area at the corresponding time, and then subtracting the discharge power of the energy storage device in the discharge state in the area at the corresponding time.

4. The method for controlling overload in a station area according to any one of claims 1 to 3, characterized in that: After the energy storage device in the substation is discharged at a value less than or equal to the rated discharge power, the adjusted second apparent power of the current substation is calculated, and whether the load rate of the current substation reaches the control target is determined according to the second apparent power; if the control target is reached, the control is terminated; If the control target is not reached, the load of the adjustable equipment in the current area is adjusted, and the adjusted third apparent power of the current area is calculated, and the control is terminated until the load rate of the current area reaches the control target.

5. The method for controlling overload in a station area according to claim 1, characterized in that: When the current substation is reversely overloaded, the energy storage device in the discharging state in the current substation stops discharging, and then the adjusted fourth apparent power of the current substation is calculated, and whether the load rate of the current substation reaches the regulation target is judged according to the fourth apparent power; if the regulation target is reached, the regulation is terminated; if the regulation target is not reached, the energy storage device in the substation is charged at a value less than or equal to the rated charging power.

6. The method for controlling overload in a station area according to claim 5, characterized in that: When the reverse load rate of the substation is greater than the preset heavy load rate of the substation transformer, it is determined that the current substation is reversely overloaded; the heavy load rate is greater than the control target.

7. The method for controlling overload in a station area according to claim 5, characterized in that: The fourth apparent power is the value obtained by subtracting the load of the pure power load of the area at the corresponding time from the photovoltaic output power of the area at the corresponding time, and then subtracting the charging power of the energy storage device in the charging state in the area at the corresponding time.

8. The method for controlling overload in a station area according to any one of claims 5 to 7, characterized in that: After charging the energy storage device in the substation at a value less than or equal to the rated charging power, the fifth apparent power of the current substation after adjustment is calculated, and whether the load rate of the current substation reaches the control target is determined according to the fifth apparent power; if the control target is reached, the control is terminated; If the control target is not reached, the photovoltaic output power of the current area is limited, and the adjusted sixth apparent power of the current area is calculated, and the control is terminated until the load rate of the current area reaches the control target.

9. A converged IoT terminal, comprising a centralized controller, characterized in that: The centralized controller is used to execute the method for controlling overload of the substation as described in any one of items 1-8 above.

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