TWI844122B - Smooth power supply switching method for electric auxiliary services - Google Patents

Abstract

A smooth power supply switching method for power auxiliary services is disclosed. The smooth power supply switching method for power auxiliary services, comprising the following steps: providing a microgrid connected to an electricity trading platform and obtaining a total output power value required by an electric auxiliary service. The mircrogrid includes a first power generation device, a second power generation device, an energy storage system and a third power generation device equipment. Providing the total output power value by the microgrid, and obtaining a first output power value of the first power generation device and a second output power value of the second power generation device. Calculating a first difference value between the total output power value with the first output power value and the second output power value. Storing or providing a power value corresponding to the first difference value by the energy storage system to perform a first smooth power supply switching procedure. Executing a second smooth power supply switching procedure when the first power generation device or the second power generation device fails.

Description

Smooth power supply switching method for power auxiliary service

The present invention relates to a power supply switching method, and in particular to a smooth power supply switching method for power auxiliary services.

The main task of power auxiliary services is to maintain the reliability of the power system. It is a short-term backup capacity used for real-time power dispatch in the stability of the power system.

In recent years, microgrids have been gradually used to provide power auxiliary services due to the integration of various power generation equipment and loads. The microgrid integrates distributed energy and loads in a region, and achieves balance and stability of the system in the region through key microgrid technologies. When necessary, it can also be disconnected from the external power system and operate independently.

However, when providing power auxiliary services, the distributed energy in the microgrid suddenly fails, or the power generation energy is insufficient (for example, solar power generation is easily affected by weather factors), and the load is unloaded or the predetermined power output is not achieved, causing the energy of the power auxiliary service provided by the microgrid to fluctuate violently, resulting in poor power supply quality.

Currently, the technologies related to power auxiliary services all focus on starting other power sources after receiving a power outage signal, intermittent power supply by absorbing renewable energy from energy storage devices, and optimizing power supply of multiple power systems. There is no relevant technology for improving power supply quality in a short period of time for power auxiliary services.

Therefore, how to provide a "smooth power supply switching method for power auxiliary services" has become a problem to be solved in the industry.

The present invention provides a method for smooth power supply switching of power auxiliary service, which includes the following steps: providing a microgrid connected to a power trading platform, and obtaining a total output power value required for a power auxiliary service, wherein the microgrid includes a first power generation device, a second power generation device, an energy storage system, and a third power generation device; providing a total output power value by the microgrid, and obtaining a first output power value of the first power generation device and a second output power value of the second power generation device; calculating a first difference between the total output power value and the first output power value and the second output power value; storing or providing a power value corresponding to the first difference by the energy storage system to execute a first smooth power supply switching procedure; and executing a second smooth power supply switching procedure when a fault occurs in the first power generation device or the second power generation device.

In some embodiments, the first power generation device is a diesel power generation device, the second power generation device is a solar power generation device, and the third power generation device is a micro-turbine power generation device.

In some embodiments, the first difference is obtained by subtracting the first output power value and the second output power value from the total output power value.

In some embodiments, when the first difference is a positive value, the energy storage system provides a power value corresponding to the first difference.

In some embodiments, when the first difference is a negative value, the energy storage system stores the power value corresponding to the first difference.

In some embodiments, the second smooth power supply switching procedure includes the following steps: obtaining a set output power value and an actual output power value of the third power generation equipment; calculating a second difference between the set output power value and the actual output power value; confirming that the second difference is positive, negative or zero; when the second difference is positive, the energy storage system provides a power value corresponding to the second difference; when the second difference is negative, the energy storage system stores the power value corresponding to the second difference; and when the second difference is zero, stopping the energy storage system from providing or storing the power value corresponding to the second difference.

In some embodiments, the second difference is obtained by subtracting the actual output power value from the set output power value.

In some embodiments, the set output power value is determined by subtracting the first output power value or the second output power value from the total output power value.

In order to make the present invention more clear and easy to understand, the following is a specific example and a detailed description with the attached drawings.

10: Taipower Trading Platform

20: Feedback

30: Microgrid

32: Diesel power generation equipment

34: Solar power generation equipment

36: Energy storage system

38: Microturbine power generation equipment

40: Load

100: Smooth power supply switching system for power auxiliary services

420,440,460,480: curve

S200~S350: Steps

T1~T3: Time point

Figure 1 is a system block diagram of an embodiment of the present invention.

Figure 2 is a flow chart of the steps of the smooth power supply switching method of the power auxiliary service of the embodiment of the present invention.

Figure 3 is a flow chart of the second smooth power supply switching procedure steps of the embodiment of the present invention.

Figure 4 is a graph showing the smooth power supply switching curve of the power auxiliary service of the embodiment of the present invention.

The specific implementation of the present invention is further described below in conjunction with the attached drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the scope of protection of the present invention.

For the sake of clarity and convenience of illustration, the components in the drawings may be enlarged or reduced in size and proportion. In the following description and/or patent application, when an element is mentioned to be "connected" or "coupled" to another element, it may be directly connected or coupled to the other element or there may be an intervening element; and when an element is mentioned to be "directly connected" or "directly coupled" to another element, there is no intervening element. Other words used to describe the relationship between elements or layers should be interpreted in the same way; ordinal numbers such as "first", "second", and "third" do not have a sequential relationship with each other, and are only used to mark and distinguish two different elements with the same name. For ease of understanding, the same elements in the following embodiments are illustrated with the same symbols.

Please refer to Figure 1, which is a system block diagram of an embodiment of the present invention. As shown in Figure 1, the smooth power supply switching system 100 of the power auxiliary service includes: Taipower trading platform 10, feeder 20, microgrid 30 and load 40.

Taipower trading platform 10 is electrically connected to the feeder 20. Microgrid 30 is electrically connected to the feeder 20. Load 40 is electrically connected to the microgrid 30.

The microgrid 30 includes: diesel power generation equipment 32, solar power generation equipment 34, energy storage system 36, micro turbine power generation equipment 38. In some embodiments, the solar power generation equipment 34 may also be other renewable energy power generation equipment such as wind power generation equipment and/or hydropower generation equipment...

It is worth noting that in this embodiment, when participating in the power auxiliary service, only the diesel generator 32, the solar generator 34 and the energy storage system 36 are used first. The reason is that when the diesel generator 32 or the solar generator 34 fails, the micro-turbine generator 38 can be used as an emergency backup energy output to maintain the power supply quality.

Please refer to Figure 2, which is a flow chart of the steps of the smooth power supply switching method of the power auxiliary service of the embodiment of the present invention. The smooth power supply switching method of the power auxiliary service of the embodiment of the present invention can be performed by a central operation platform with a computer system, or an information processing device with computer functions to perform the following steps.

Step S200, provide the microgrid 30 with a connection to the Taipower trading platform 10, and obtain the total output power value P1 required for the power auxiliary service issued by the Taipower trading platform 10. When the microgrid 30 receives the power command, it can choose to turn off unnecessary loads 40, or turn on other power generation equipment in the field to provide self-sufficient energy.

In step S210, the total output power value P1 is provided by the microgrid 30, and the first output power value P2 of the first power generation equipment (i.e., the diesel power generation equipment 32) and the second output power value P3 of the second power generation equipment (i.e., the solar power generation equipment 34) are obtained. Generally speaking, if the sunshine time is long, the power generation of the solar power generation equipment 34 will increase. On the contrary, if the sunshine time is short, the power generation of the solar power generation equipment 34 will decrease. Therefore, the solar power generation equipment 34 is an unstable power source.

Step S220, calculate the first difference between the total output power value P1 and the first output power value P2 and the second output power value P3. The first difference is obtained by subtracting the first output power value P2 and the second output power value P3 from the total output power value P1. Because, when there is sufficient sunshine, the first output power value P2+the second output power value P3>the total output power value P1, and when there is insufficient sunshine, the first output power value P2+the second output power value P3<the total output power value P1. Therefore, the first difference may be positive, negative or zero.

In step S230, the energy storage system 36 stores or provides a power value corresponding to the first difference to execute a first smooth power supply switching procedure. Since the energy storage system 36 has the characteristic of rapid response to charging and discharging, the problem of power supply quality can be improved in a short time. For example, when the first difference is a positive value, the energy storage system 36 provides a power value corresponding to the first difference. When the first difference is a negative value, the energy storage system 36 stores the power value corresponding to the first difference. In other words, in order to avoid drastic changes in the energy of the power auxiliary service provided by the microgrid 30, the energy storage system 36 is used to compensate for the required power value, or to store the overflow power value, so as to provide a smooth power supply switching effect. When the first difference is zero, the energy storage system 36 stops providing or storing the power value corresponding to the first difference.

Step S240, confirm whether the first power generation equipment or the second power generation equipment is faulty? Since the fault or instability of the power generation equipment will affect the first output power value P2 and the second output power value P3, the power supply quality of the power auxiliary service provided by the microgrid 30 is poor. In some embodiments, it can also be confirmed whether the first power generation equipment and the second power generation equipment are faulty at the same time.

Step S250, when it is confirmed that the first power generation equipment or the second power generation equipment has failed, the microgrid 30 executes the second smooth power supply switching procedure.

Please refer to Figure 3, which is a flow chart of the second smooth power supply switching procedure of the embodiment of the present invention. As shown in Figure 3, step S300 obtains a set output power value P4 and an actual output power value P5 of the third power generation equipment (i.e., the micro-turbine power generation equipment 38).

Step S310, calculate the second difference between the set output power value P4 and the actual output power value P5. In some implementations, the set output power value P4 is determined by subtracting the first output power value P2 or the second output power value P3 from the total output power value P1, that is, P4=P1-P2, or P4=P1-P3. In some implementations, the set output power value P4 is determined by subtracting the first output power value P2 and the second output power value P3 from the total output power value P1, that is, P4=P1-(P2+P3). The second difference is obtained by subtracting the actual output power value P5 from the set output power value P4.

Step S320, confirm whether the second difference is positive, negative or zero? Since it takes time for the output energy of the micro-turbine power generation device 38 to reach stability, the actual output power value P5 may be greater than, less than or equal to the set output power value P4, so the second difference may be positive, negative or zero.

In step S330, when the second difference is a positive value, the energy storage system 36 provides a power value corresponding to the second difference. In step S340, when the second difference is a negative value, the energy storage system 36 stores the power value corresponding to the second difference. In step S350, when the second difference is zero, the energy storage system 36 stops providing or storing the power value corresponding to the second difference. Since the reaction time of the micro-turbine power generation equipment 38 is relatively long, it takes some time for the actual output power value P5 to be equal to the set output power value P4. Therefore, the rapid reaction of the energy storage system 36 is used to make up for the power supply drop during this period of time, thereby providing a smooth power supply switching effect.

It is worth noting that although the micro-turbine power generation equipment 38 has a longer response time, it can provide a relatively high power output energy. Therefore, the output capacity of the energy storage system 36 does not need to be designed to be too large, which can reduce the construction cost of the energy storage system 36.

Next, please refer to Figure 4, which is a smooth power supply switching curve diagram of the power auxiliary service of the embodiment of the present invention. As shown in Figure 4, the horizontal axis is time, the unit is seconds (sec), and the vertical axis is the output power value, the unit is kilowatts (kw).

The first output power value P2 of the diesel generator 32 is shown as curve 420. It can be seen that the output energy of the diesel generator 32 is relatively stable. The second output power value P3 of the solar generator 34 is shown as curve 440. It can be seen that the output energy of the solar generator 34 is relatively unstable. The output power value of the energy storage system 36 is shown as curve 460. The total output power value P1 is shown as curve 480. In addition, for the convenience of explanation, the curve corresponding to the micro-turbine generator 38 is not shown in Figure 4.

When the solar power generation equipment 34 is set to fail or power supply is unstable at time point T1, the second output power value P3 begins to decrease, causing the total output power value P1 to change. Then, the microgrid 30 starts to execute the smooth power supply switching procedure, and the energy storage system 36 starts to provide the corresponding power value at time point T2 to quickly make up for the power supply gap of the power auxiliary service. As shown in Figure 4, the curve 480 starts to change from time point T1 and returns to normal at time point T3. The time from time point T1 to time point T3 is about 6 seconds. It can be seen that the smooth power supply switching method of the embodiment of the present invention can improve the power supply quality of the power auxiliary service in a short time.

In summary, the smooth power supply switching method of the power auxiliary service of the embodiment of the present invention can quickly and smoothly switch and maintain stable power supply if a distributed power source fails or becomes unstable during the process of using each distributed power source to provide power auxiliary service in the microgrid, thereby improving the power supply quality of the power auxiliary service.

The micro-turbine power generation equipment according to the embodiment of the present invention can provide a relatively large output energy, thereby the output power of the energy storage system can be relatively reduced. Therefore, the capacity of the energy storage system does not need to be designed too large, which can reduce the construction cost of the energy storage system.

The energy storage system according to the embodiment of the present invention can provide the power supply gap required in the first smooth power supply switching procedure and the second smooth power supply switching procedure, and can improve the power supply quality of the power auxiliary service in a short time.

Although the present invention has been disclosed as above by the embodiments, it is not intended to limit the present invention. Anyone with common knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined in the attached patent application.

S200~S250: Steps

Claims (8)

A method for smooth power supply switching of power auxiliary service includes the following steps: Providing a microgrid connected to a power trading platform and obtaining a total output power value required for a power auxiliary service, the microgrid including a first power generation device, a second power generation device, an energy storage system and a third power generation device; The microgrid provides the total output power value, and obtains a first output power value of the first power generation device and a second output power value of the second power generation device; Calculating a first difference between the total output power value and the first output power value and the second output power value; The energy storage system stores or provides a power value corresponding to the first difference to execute a first smooth power supply switching procedure; and When a fault occurs in the first power generation device or the second power generation device, a second smooth power supply switching procedure is executed. A smooth power supply switching method for power auxiliary service as described in claim 1, wherein the first power generation equipment is a diesel power generation equipment, the second power generation equipment is a solar power generation equipment, and the third power generation equipment is a micro-turbine power generation equipment. A smooth power supply switching method for power auxiliary service as described in claim 1, wherein the first difference is obtained by subtracting the first output power value and the second output power value from the total output power value. A smooth power supply switching method for power auxiliary service as described in claim 3, wherein when the first difference is a positive value, the energy storage system provides a power value corresponding to the first difference. A smooth power supply switching method for power auxiliary service as described in claim 3, wherein when the first difference is a negative value, the energy storage system stores a power value corresponding to the first difference. The method for smooth power supply switching of power auxiliary service as described in claim 1, wherein the second smooth power supply switching procedure includes the following steps: Obtaining a set output power value and an actual output power value of the third power generation equipment; Calculating a second difference between the set output power value and the actual output power value; Confirming that the second difference is positive, negative or zero; When the second difference is positive, the energy storage system provides a power value corresponding to the second difference; When the second difference is negative, the energy storage system stores the power value corresponding to the second difference; and When the second difference is zero, stop the energy storage system from providing or storing the power value corresponding to the second difference. A smooth power supply switching method for power auxiliary service as described in claim 6, wherein the second difference is obtained by subtracting the actual output power value from the set output power value. A smooth power supply switching method for power auxiliary service as described in claim 6, wherein the set output power value is determined by subtracting the first output power value or the second output power value from the total output power value.

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