Electric power system and black start method for electric power system
By classifying electrical equipment in the power system into two categories and setting up automatic backup power supply devices, the safety hazards and cost issues of black start in large-capacity power systems have been resolved, and the stable restoration of power supply to the power system has been achieved.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- CONTEMPORARY AMPEREX FUTURE ENERGY RES INST (SHANGHAI) LTD
- Filing Date
- 2025-12-04
- Publication Date
- 2026-06-25
AI Technical Summary
Existing black-start methods for power systems pose safety risks in large-capacity power systems and cannot meet the power demand of stations, leading to increased operating costs.
The electrical equipment in the power system is divided into two categories and connected by two power supply lines. A main power supply and a backup power supply are set up. When the main power supply fails, the backup power supply is switched to ensure that the first category of electrical equipment is continuously powered during black start.
It improves the safety and stability of the black start process, reduces operating costs, and ensures continuous power supply to critical electrical equipment during power system restoration.
Smart Images
Figure CN2025139887_25062026_PF_FP_ABST
Abstract
Description
Power systems and black start methods for power systems
[0001] This application claims priority to Chinese Patent Application No. 202411906400.9, filed on December 20, 2024, entitled "Power System and Black Start Method for Power System", the contents of which are incorporated herein by reference in their entirety. Technical Field
[0002] This application relates to the field of power system technology, and more specifically, to a power system and a black start method for a power system. Background Technology
[0003] Black start refers to the process by which a power system, after being shut down due to a fault, is restored without the assistance of an external network. This is achieved by starting generators with self-starting capabilities within the power system, thereby driving generators without self-starting capabilities, gradually expanding the scope of power system restoration, and ultimately restoring the entire power system.
[0004] As the capacity of power supply equipment in the power system increases, the power demand of the power system during black start also increases. The current black start logic cannot meet the requirements of black start, which may lead to some safety hazards during black start. Summary of the Invention
[0005] The purpose of this application is to provide a power system and a black start method for the power system, which can improve the safety and stability of the black start process.
[0006] In a first aspect, the present invention provides a power system, comprising: a main power supply connected to a first busbar and a second busbar; the first busbar being used to connect a first type of electrical equipment, the main power supply and the first type of electrical equipment being connected via a first set of switches; the second busbar being used to connect a second type of electrical equipment, the main power supply and the second type of electrical equipment being connected via a second set of switches; and a first backup power supply connected to a third busbar; the third busbar being used to connect the first type of electrical equipment, the first backup power supply and the first type of electrical equipment being connected via a third set of switches; wherein the main power supply is used to supply power to the first type of electrical equipment and the second type of electrical equipment; in the event of a power failure of the main power supply, the first backup power supply is used to supply power to the first type of electrical equipment during a black start of the power system.
[0007] In the above implementation, electrical equipment within the power system is divided into two categories and connected via two power supply lines. When needed, such as in cases of insufficient power supply, the first category of equipment can be supplied independently. Furthermore, a first backup power source is provided, which can supply power to the first category of equipment during black start-up. This allows the first category of equipment to provide corresponding services to the power system during black start-up, thereby better protecting the stability of the power system during black start-up and improving black start safety.
[0008] In an optional implementation, it further includes: a first backup power automatic switching device connected to the first busbar and the third busbar, used to switch the first type of electrical equipment to the first busbar or the third busbar based on the obtained voltage of the first busbar and the third busbar, so as to switch the main power supply or the first backup power supply to supply power to the first type of electrical equipment.
[0009] In the above implementation method, by setting the first backup power automatic switching device, the power source can be switched more automatically. Based on the function of the first backup power automatic switching device, the timing of switching can be identified more promptly, thus better keeping the first type of electrical equipment in a powered state. This also ensures the stability and safety of the first type of electrical equipment during the black start of the power system.
[0010] In an optional implementation, the system further includes: the first busbar connects to multiple branches, each branch being used to connect one or more Class I electrical devices; the third busbar connects to multiple branches, each branch being used to connect one or more Class I electrical devices, wherein the number of branches of the first busbar is the same as the number of branches of the third busbar; each branch of the first busbar and its corresponding branch of the third busbar are provided with a first automatic backup power supply device for switching the connection of the Class I electrical device connected to the branch to the first busbar or the third busbar.
[0011] In the above implementation, multiple branches can be designed on the first busbar and the third busbar. This allows for power supply based on multiple branches of the third busbar even when more Class I electrical devices need to operate during black start. Furthermore, the stability of black start is better protected by allowing multiple Class I electrical devices to operate during black start.
[0012] In an optional implementation, the first switch group includes a switch connected between the first busbar and the main power supply, and a switch connected between the first busbar and the first type of electrical equipment.
[0013] In an optional embodiment, the third set of switches includes a switch connected between the third busbar and the first backup power supply, and a switch connected between the third busbar and the first type of electrical equipment.
[0014] In the above implementation, in addition to disconnecting the main power supply from the first type of electrical equipment by disconnecting the connection between the first busbar and the main power supply, the connection between the main power supply and the first type of electrical equipment can also be achieved by disconnecting the connection between the first busbar and the first type of electrical equipment. Thus, through the control of multiple switches, the safety of the first type of electrical equipment can be better protected when the main power supply fails, and the connection between the main power supply and the first type of electrical equipment can be disconnected in a timely manner.
[0015] In an optional embodiment, the first switch group includes a switch connected between the first busbar and the main power supply, and a switch connected between the first busbar and the first type of electrical equipment; the third switch group includes a switch connected between the third busbar and the first backup power supply, a switch for connecting the first busbar and the third busbar, and a switch shared with the first switch group that is connected between the first busbar and the first type of electrical equipment.
[0016] In the above implementation, the first busbar and the third busbar can be connected and disconnected by a single switch. This single switch can connect the first backup power supply to the first type of electrical equipment, reducing the need for a large number of switches, making the circuit structure simpler and easier to implement.
[0017] In an optional embodiment, the first switch group includes a switch connected between the first busbar and the main power supply, and a switch connected between the first busbar and the first type of electrical equipment; the second switch group includes a switch shared with the first switch group connected between the first busbar and the main power supply, a switch for connecting the first busbar and the second busbar, and a switch connected between the second busbar and the second type of electrical equipment.
[0018] In the above implementation, the first busbar and the second busbar can be connected and disconnected by a single switch. This single switch can connect the main power supply to the second type of electrical equipment, reducing the need for a large number of switches, making the circuit structure simpler and easier to implement.
[0019] In an optional implementation, it further includes: a second backup power supply connected to a branch of the first busbar, and a switch connected to the branch where the second backup power supply is located; wherein, when the switch on the branch where the second backup power supply is located is closed, the second backup power supply supplies power to the first type of electrical equipment.
[0020] In the above implementation, a second backup power supply can also be provided. This second backup power supply can be connected to the first type of electrical equipment. In the event that both the first backup power supply and the main power supply fail, the second backup power supply can be activated to supply power to the first type of electrical equipment, thereby better ensuring that the first type of electrical equipment is in a powered state during black start.
[0021] In an optional embodiment, it further includes: an automatic switching device for the second backup power supply located at a switch on the branch where the second backup power supply is located, used to control the closing and opening of the switch on the branch where the second backup power supply is located based on the power failure status of the main power supply and the first backup power supply.
[0022] In the above implementation method, a second backup power supply automatic switching device can also be set up, which can more flexibly realize the second backup power supply to supply power to the first type of electrical equipment and disconnect the second backup power supply to supply power to the first type of electrical equipment.
[0023] In an optional implementation, an energy storage system connected to the first busbar is also included, and a switch is connected between the energy storage system and the first busbar.
[0024] In an optional implementation, the electrical equipment in the first type of electrical equipment is a safety device in the power system.
[0025] In the above implementation method, the first type of electrical equipment is a safety device. By operating the safety device during black start, the safety of the power system during black start can be better protected.
[0026] Secondly, the present invention provides a black start method for a power system, applied to the power system described in any of the foregoing embodiments. The black start method includes: disconnecting the main power supply from a first type of electrical device and disconnecting the main power supply from a second type of electrical device when a power failure is detected; controlling the connection between the first type of electrical device and a first backup power supply, and using the first backup power supply to supply power to the first type of electrical device during the black start of the power system; and reconnecting the main power supply from the first type of electrical device and the second type of electrical device when the voltage of the bus where the main power supply is located is detected to return to normal.
[0027] In the above implementation method, the power supply head of the first type of electrical equipment can be controlled in a timely manner by monitoring the power failure of the main power supply, so as to better ensure that the first type of electrical equipment is in a powered state during black start, thereby enabling the first type of electrical equipment to maintain a better service state during black start.
[0028] In an optional implementation, the method further includes: disconnecting the main power supply from the first type of electrical equipment and disconnecting the main power supply from the second type of electrical equipment when both the main power supply and the first backup power supply are detected to be out of power; controlling the connection between the first type of electrical equipment and the second backup power supply, and using the second backup power supply to supply power to the first type of electrical equipment during the black start of the power system; and connecting the main power supply to the first type of electrical equipment and connecting the main power supply to the second type of electrical equipment when the voltage of the bus where the main power supply is located is detected to return to normal.
[0029] In an optional implementation, when both the main power supply and the first backup power supply are detected to be out of power, disconnecting the main power supply from the first type of electrical equipment and disconnecting the main power supply from the second type of electrical equipment includes: monitoring the first voltage of the first busbar connected to the main power supply and the second voltage of the third busbar connected to the first backup power supply through the first backup power supply automatic switching device; when it is determined based on the first voltage of the first busbar and the third voltage of the third busbar that both the main power supply and the first backup power supply are out of power, controlling the disconnection of the main power supply from the first type of electrical equipment and disconnection of the main power supply from the second type of electrical equipment through the first backup power supply automatic switching device; controlling the connection between the first type of electrical equipment and the second backup power supply includes: controlling the connection between the first type of electrical equipment and the second backup power supply through the second backup power supply automatic switching device.
[0030] In an optional implementation, disconnecting the main power supply from the first type of electrical equipment and disconnecting the main power supply from the second type of electrical equipment when a main power supply failure is detected includes: monitoring the voltage of the first busbar connected to the main power supply via a first automatic backup power supply switching device; and, if a main power supply failure is determined based on the voltage of the first busbar, controlling the disconnection of the main power supply from the first type of electrical equipment and disconnecting the main power supply from the second type of electrical equipment via the first automatic backup power supply switching device; controlling the connection between the first type of electrical equipment and the first backup power supply includes: controlling the connection between the first type of electrical equipment and the first backup power supply via the first automatic backup power supply switching device. Attached Figure Description
[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0032] Figure 1 is a circuit diagram of a power system provided in an embodiment of this application;
[0033] Figure 2 is another circuit diagram of the power system provided in an embodiment of this application;
[0034] Figure 3 is a schematic diagram of the control flow based on the power system shown in Figure 2 provided in an embodiment of this application;
[0035] Figure 4 is another circuit diagram of the power system provided in the embodiment of this application;
[0036] Figure 5 is a schematic diagram of the control flow based on the power system shown in Figure 4 provided in an embodiment of this application;
[0037] Figure 6 is a flowchart of the black start method provided in an embodiment of this application;
[0038] Figure 7 is another flowchart of the black start method provided in the embodiments of this application.
[0039] Icons: 110 - Main power supply; 120 - First backup power supply; 130 - Class I electrical equipment; 140 - Class II electrical equipment; 150 - Second backup power supply; K1 - First switch; K2 - Second switch; K3 - Third switch; K4 - Fourth switch; K5 - Fifth switch; K6 - Sixth switch; K7 - Seventh switch; K9 - Ninth switch; K10 - Tenth switch; K11 - Eleventh switch; K12 - Twelfth switch; K13 - Thirteenth switch; K14 - Fourteenth switch; K15 - Fifteenth switch; B1 - First busbar; B2 - Second busbar; B3 - Third busbar; ESS - Energy storage system; InP - AC power grid; OutP - External power supply; QF1 - First busbar switch; QF2 - Second busbar switch. Embodiments of the present invention
[0040] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.
[0041] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0042] Currently, the gradual expansion of the power grid and the continuous increase in voltage levels have led to a corresponding increase in the complexity of the power system, posing numerous challenges to its safe operation. In some sudden situations, such as extreme weather, localized faults in the power system may occur, leading to large-scale power outages. The first step in power system restoration is black start, making the black start process crucial for power system recovery.
[0043] As new power grids develop towards higher voltage and larger capacity, the capacity of power systems is increasing, and the power demand at power stations during black starts is also increasing. Currently, diesel generators or energy storage vehicles are mostly used as power supply equipment during black starts. However, the capacity of diesel generators or energy storage vehicles increases with power demand, greatly increasing operating costs.
[0044] Based on the above research, the embodiments of this application can provide a power system and a black start method for the power system, which can supply power to only some electrical equipment during the black start period, and then gradually restore power to other electrical equipment after the power system is restored.
[0045] To facilitate understanding of this embodiment, we will first introduce a power system that enables more stable black start according to the embodiments of this application.
[0046] Figure 1 shows a circuit diagram of a power system provided in an embodiment of this application. The power system may include a main power supply 110 and a first backup power supply 120.
[0047] The main power supply 110 is connected to the first busbar B1 and the second busbar B2; the first busbar B1 is used to connect the first type of electrical equipment 130, and the main power supply 110 and the first type of electrical equipment 130 are connected through the first switch group.
[0048] Among them, the electrical equipment in the first category 130 is safety equipment in the power system. For example, the first category of electrical equipment 130 can be the minimum required electrical load during the black start period of the power system. For example, the minimum required electrical load can include, but is not limited to, electrical equipment such as HVAC, fire protection, and valve cooling.
[0049] The aforementioned first switch group can disconnect the main power supply 110 from the first type of electrical equipment 130. For example, the first switch group may include a switch disposed between the main power supply 110 and the first busbar B1, and may also include a switch on the branch line connecting the first busbar B1 to the first type of electrical equipment. Disconnecting any switch on the main power supply 110 connecting the first type of electrical equipment 130 to the first type of electrical equipment can cut off the main power supply 110's power supply to the first type of equipment.
[0050] In the example shown in Figure 1, the first switch group includes a first switch K1, a third switch K3, a fifth switch K5, a sixth switch K6, and a seventh switch K7.
[0051] The second busbar B2 is used to connect the second type of electrical equipment 140. The main power supply 110 is connected to the second type of electrical equipment 140 through a second set of switches. In the example shown in Figure 1, the second set of switches may include the first busbar switch QF1 and the ninth switch K9.
[0052] The aforementioned second set of switches can disconnect the main power supply 110 from the second type of electrical equipment 140. For example, this second set of switches may include a switch disposed between the main power supply 110 and the second busbar B2, and may also include a switch on the branch line of the second busbar B2 connecting to the second type of electrical equipment. Disconnecting any switch on the main power supply 110 connecting the second type of electrical equipment 140 to the second type of electrical equipment can cut off the main power supply 110's power supply to the second type of equipment.
[0053] The first backup power supply 120 is connected to the third busbar B3; the third busbar B3 is used to connect the first type of electrical equipment 130, and the main power supply 110 is connected to the first type of electrical equipment 130 through a third set of switches. In the example shown in Figure 1, the third set of switches may include the eleventh switch K11, the twelfth switch K12, the second busbar switch QF2, and the fifth switch K5, the sixth switch K6, and the seventh switch K7 shared with the first set of switches.
[0054] The aforementioned third set of switches can disconnect the first backup power supply 120 from the first type of electrical equipment 130. For example, the third set of switches may include a switch located between the first backup power supply 120 and the third busbar B3, and may also include a switch on the branch line of the third busbar B3 connecting to the first type of electrical equipment. Disconnecting any switch on the first backup power supply 120 from the first type of electrical equipment 130 can cut off the power supply from the first backup power supply 120 to the first type of equipment.
[0055] When the main power supply 110 of the power system is in normal condition, the first and second switch groups are closed, and any switch in the third switch group is open, the main power supply 110 supplies power to the first type of electrical equipment 130 and the second type of electrical equipment 140.
[0056] When the main power supply 110 loses power and the first backup power supply 120 is normal, the connection between the main power supply 110 and the first type of electrical equipment 130, and the connection between the main power supply 110 and the second type of electrical equipment 140 are disconnected by adjusting the switch states of the first and second switch groups. The third switch group is closed, and the power system is in a black start. During the black start, the first backup power supply 120 supplies power to the first type of electrical equipment 130.
[0057] Alternatively, the power system can be any type of power system, such as a new type of power system, a smart power system, or an energy storage power station.
[0058] In the power system provided in the above embodiments, under normal circumstances, the main power supply 110 can supply power to various electrical devices. However, in the event of a power failure of the main power supply 110, during black start, the connection between the main power supply 110 and various electrical devices can be disconnected, and the connection between the first backup power supply 120 and the first type of electrical device 130 can be established. The first backup power supply 120 then supplies power only to the first type of electrical device 130, thereby reducing power demand and better ensuring the safety of the black start operating environment and improving the stability of black start.
[0059] To enable more flexible switching of power sources, the power system may also include an automatic transfer switch (ATS). The ATS is used to switch power sources.
[0060] Optionally, the power system is equipped with an automatic switching device for a first backup power supply 120 connected to the first busbar B1 and the third busbar B3, which is used to switch the connection of the first type of electrical equipment 130 to the first busbar B1 or the third busbar B3 based on the obtained voltage of the first busbar B1 and the third busbar B3, so as to switch the main power supply 110 or the first backup power supply 120 to supply power to the first type of electrical equipment 130.
[0061] To connect a larger number of Class I electrical devices 130, the first busbar B1 is provided with multiple branches, each branch being used to connect one Class I electrical device 130. The third busbar B3 can also be provided with multiple branches, each branch being used to connect one Class I electrical device 130.
[0062] The number of branches of the first busbar B1 is the same as the number of branches of the third busbar B3.
[0063] For example, the branches on the first busbar B1 can correspond one-to-one with the branches on the third busbar B3. Each branch of the first busbar B1 and its corresponding branch of the third busbar B3 are equipped with a first backup power supply 120 automatic switching device, which is used to switch the connection of the first type of electrical equipment 130 connected to the branch to the first busbar B1 or the third busbar B3.
[0064] The automatic switching device for the first backup power supply 120, which connects the branches of the first busbar B1 and the branches of the third busbar B3, can connect the branches of the first busbar B1 to the first type of electrical equipment 130, or connect the branches of the third busbar B3 to the first type of electrical equipment 130, based on the voltage of the first busbar B1 and the voltage of the third busbar B3.
[0065] For example, when the automatic switching device for the first backup power supply 120 detects that the voltage status of the first bus B1 indicates a power failure of the main power supply 110, it can disconnect the branch of the first bus B1 from the first type of electrical equipment 130 and connect the branch of the third bus B3 to the first type of electrical equipment 130, so that the first backup power supply 120 supplies power to the first type of electrical equipment 130. When the automatic switching device for the first backup power supply 120 detects that the voltage of the first bus B1 has returned to normal, it can connect the branch of the first bus B1 to the first type of electrical equipment 130, so that the main power supply 110 supplies power to the first type of electrical equipment 130. Optionally, when the branch of the first bus B1 is connected to the first type of electrical equipment 130, the connection between the branch of the third bus B3 and the first type of electrical equipment 130 can be disconnected. Optionally, the connection between the branch of the third bus B3 and the first type of electrical equipment 130 can also be disconnected after a specified delay.
[0066] Taking the example shown in Figure 2, three Class I electrical devices 130 are illustrated: a valve cooling device, a fire-fighting device, and a heating, ventilation, and air conditioning (HVAC) device. The first busbar B1 has three branches, each capable of connecting one Class I electrical device 130. The third busbar B3 also has three branches, each capable of connecting one Class I electrical device 130. The three branches of the first busbar B1 and the three branches of the third busbar B3 correspond one-to-one, and each pair of branches of the first busbar B1 and the third busbar B3 is equipped with an automatic switching device for a first backup power supply 120.
[0067] Of course, depending on the actual usage scenario, it may include more or fewer Class I electrical equipment 130.
[0068] The power system provided in this embodiment may also include some second type of electrical equipment 140. The second type of electrical equipment 140 may be electrical equipment that is not necessary for the black start process in the power system. When the main power supply 110 is in normal state, the second type of electrical equipment 140 may be powered by the main power supply 110.
[0069] In this embodiment, in order to adapt to the power supply requirements under various scenarios and to make the switching between power supplies and electrical equipment more flexible, the switch arrangement between power supplies and electrical equipment can be reasonably designed.
[0070] Optionally, the first switch group includes a switch connected between the first busbar B1 and the main power supply 110, and a switch connected between the first busbar B1 and the first type of electrical equipment 130. In the example shown in FIG1, the first switch group includes a first switch K1, a third switch K3, a fifth switch K5, a sixth switch K6, and a seventh switch K7.
[0071] Optionally, the second set of switches includes a switch connected between the second busbar B2 and the main power supply 110, and a switch connected between the second busbar B2 and the second type of electrical equipment 140. Optionally, the second set of switches may include a switch shared with the first switch group, connecting the first busbar B1 and the main power supply; a switch for connecting the first busbar B1 and the second busbar B2; and a switch connected between the second busbar B2 and the second type of electrical equipment 140. In the example shown in FIG1, the second set of switches includes a first switch K1 and a third switch K3 shared with the first switch group, and also includes a first busbar switch QF1 and a ninth switch.
[0072] In the example shown in Figure 1, the switch connecting the first busbar and the second busbar can be the first busbar switch QF1.
[0073] When the first busbar switch QF1 is closed, the main power supply 110 is connected to the second type of electrical equipment 140.
[0074] Optionally, the first busbar switch QF1 can also be configured with an automatic backup power supply device. This device can automatically disconnect the first busbar switch QF1 based on the voltage status of the first busbar B1 to disconnect the second type of electrical equipment 140 from the main power supply 110, or close the first busbar switch QF1 to connect the second type of electrical equipment 140 to the main power supply 110. For example, when the automatic backup power supply device configured on the first busbar switch QF1 detects that the voltage status of the first busbar B1 indicates that the main power supply 110 has lost power, it can automatically disconnect the first busbar switch QF1 to disconnect the second type of electrical equipment 140 from the main power supply 110; when the automatic backup power supply device configured on the first busbar switch QF1 detects that the voltage of the first busbar B1 has returned to normal, it can automatically close the first busbar switch QF1 to connect the second type of electrical equipment 140 to the main power supply 110.
[0075] Optionally, the third set of switches includes a switch connected between the third busbar B3 and the first backup power supply 120, and a switch connected between the third busbar B3 and the first type of electrical equipment 130. In the example shown in Figure 2, the third set of switches may include an eleventh switch K11, a twelfth switch K12, a second busbar switch QF2, a thirteenth switch K13, a fourteenth switch K14, and a fifteenth switch K15.
[0076] To more quickly connect the first backup power supply 120 to the first type of electrical equipment 130, the third set of switches may include a switch connected between the third busbar and the first backup power supply, a switch for connecting the first busbar B1 and the third busbar B3, and a switch shared with the first switch group that connects the first busbar B1 and the first type of electrical equipment 130. In the example shown in Figure 1, the third set of switches may include an eleventh switch K11, a twelfth switch K12, a second busbar switch QF2, and a fifth switch K5, a sixth switch K6, and a seventh switch K7 shared with the first switch group.
[0077] The switch between the first busbar B1 and the third busbar B3 can be the second busbar switch QF2.
[0078] When the second busbar switch QF2 is closed, the first backup power supply 120 is connected to the first type of electrical equipment 130.
[0079] Optionally, the second bus switch QF2 can also be configured with an automatic backup power supply device. This device can automatically disconnect the second bus switch QF2 based on the voltage conditions of the first bus B1 and the third bus B3, thereby disconnecting the first type of electrical equipment 130 from the first backup power supply 120. Alternatively, it can close the second bus switch QF2 to connect the first type of electrical equipment 130 to the first backup power supply 120. For example, if the automatic backup power supply device configured on the second bus switch QF2 detects that the voltage state of the first bus B1 indicates that the first backup power supply 120 is de-energized, and the voltage state of the third bus B3 indicates that the first backup power supply 120 is normal, it can automatically close the second bus switch QF2 to connect the first type of electrical equipment 130 to the first backup power supply 120. If the automatic backup power supply device configured on the second bus switch QF2 detects that the voltage of the first bus B1 has returned to normal, it can disconnect the second bus switch QF2 to connect the first type of electrical equipment 130 to the main power supply 110.
[0080] In this embodiment, as shown in FIG4, a switch may also be provided between the first busbar B1 and the main power supply 110. When the main power supply 110 loses power, the switch may also be opened to disconnect the main power supply 110 from the first type of power supply. The switch between the first busbar B1 and the main power supply 110 may also be equipped with an automatic backup power supply device. The automatic backup power supply device can detect the voltage on its line and determine whether the main power supply 110 has lost power based on the voltage. If it is determined that the main power supply 110 has lost power, the switch between the first busbar B1 and the main power supply 110 may be opened to disconnect the first type of electrical equipment 130 connected to the first busbar B1 from the main power supply 110.
[0081] In one scenario, both the main power supply 110 and the first backup power supply 120 may lose power. Therefore, in order to enable the power system to achieve black start more stably and safely, as shown in Figure 2 or Figure 4, the power system of this application embodiment may further include a second backup power supply 150 connected to a branch of the first busbar B1, and a switch connected to the branch where the second backup power supply 150 is located.
[0082] When the switch on the branch where the second backup power supply 150 is located is closed, the second backup power supply 150 supplies power to the first type of electrical equipment 130.
[0083] The switch on the branch where the second backup power supply 150 is located can be equipped with an automatic switching device for the second backup power supply 150. This automatic switching device can also determine whether the second backup power supply 150 needs to be activated based on the voltage on the first bus B1 and the voltage on the third bus B3. For example, if the voltage status of the first bus B1 indicates that the main power supply 110 is out of power, and the voltage on the third bus B3 indicates that the first backup power supply 120 is also out of power, the automatic switching device for the second backup power supply 150 can close the switch on the branch where the second backup power supply 150 is located, so that the second backup power supply 150 can be connected to the first type of electrical equipment 130 to supply power to the first type of electrical equipment 130. If the voltage status of the first bus B1 indicates that the main power supply 110 is restored, the connection between the main power supply 110 and the first type of electrical equipment 130 can be restored. Furthermore, the automatic switching device for the second backup power supply 150 configured on the switch of the branch where the second backup power supply 150 is located can control the switch on the branch where the second backup power supply 150 is located to disconnect after a specified delay, thereby cutting off the connection between the second backup power supply 150 and the first type of electrical equipment 130. This specified delay can be a pre-set duration, for example, a value between 100ms and 1s, such as 100ms, 200ms, 500ms, or 1s. By delaying the disconnection of the second backup power supply 150 from the first type of electrical equipment 130, the first type of electrical equipment 130 can be better ensured to remain energized, thus improving the safety of black starts.
[0084] The power system provided in this application embodiment can be an energy storage power station, as shown in Figures 2 and 4. The energy storage power station can include an energy storage system ESS connected to the first bus B1, and a switch is connected between the energy storage system ESS and the first bus B1.
[0085] Optionally, the energy storage system ESS may include one or more energy storage units, which may be energy storage submodules or a single PCS (Power Conversion System). Each energy storage unit may consist of a power module connected in parallel with a battery module. The battery module may be a single-branch series battery module or a multi-branch series-parallel battery module.
[0086] The following description, in conjunction with Figures 2 and 4, details the specific implementation methods of black start for the power system under different conditions and the corresponding control flow.
[0087] As shown in Figure 2, the main power supply 110 can be an AC grid InP, with a first switch K1 connected to it. An energy storage system ESS can be connected in parallel to the AC grid InP, with a tenth switch K10 connected to the ESS. A first transformer can be installed between the AC grid InP and the first busbar B1, with switches on both sides of the first transformer, namely a second switch K2 and a third switch K3. The first backup power supply 120 can be an off-site power supply OutP, with a second transformer installed between the off-site power supply OutP and the third busbar B3. Switches can also be installed on both sides of this second transformer, namely an eleventh switch K11 and a twelfth switch K12.
[0088] The AC power grid InP can be used to supply power to various electrical devices. The first busbar B1 can be used to connect to the first type of electrical equipment 130. In the example shown in Figure 2, the first type of electrical equipment 130 includes valve cooling, fire protection, and HVAC systems. The first busbar B1 can also connect to three branches, which are used to connect to the valve cooling, fire protection, and HVAC systems respectively. Each of the three branches is equipped with a switch: the fifth switch K5, the sixth switch K6, and the seventh switch K7. The third busbar B3 can also connect to three branches, which are used to connect to the valve cooling, fire protection, and HVAC systems respectively. Each of the three branches is equipped with a switch: the thirteenth switch K13, the fourteenth switch K14, and the fifteenth switch K15.
[0089] The AC power grid InP can also be connected to a second busbar B2, which is connected to the first busbar B1 via a first busbar switch QF1. The second busbar B2 is used to connect a second type of electrical equipment 140, and the line containing the second type of electrical equipment 140 can be connected to a ninth switch K9. When the first busbar switch QF1 is closed, the first busbar B1 and the second busbar B2 can be connected, and the AC power grid InP can supply power to the electrical equipment connected to the first busbar B1 and the electrical equipment connected to the second busbar B2.
[0090] In the example shown in Figure 2, the second backup power supply 150 can be an external power supply, which can be connected to a branch of the first busbar B1, on which a fourth switch K4 can be installed.
[0091] In this example, automatic transfer switches for backup power are installed on branches of the first busbar B1 and the third busbar B3. The AC grid InP and the energy storage system ESS connected to the first busbar B1 are the main power sources, while the external power source OutP connected to the third busbar B3 is the backup power source. When the main power source connected to the first busbar B1 fails, the automatic transfer switch 120 for the first backup power source can quickly disconnect the fifth switch K5 and close the thirteenth switch K13; the sixth switch K6 and disconnect the fourteenth switch K14; and the seventh switch K7 and close the fifteenth switch K15.
[0092] As shown in Figure 3, based on the implementation of the power system shown in Figure 2, its specific control logic can be expressed as follows: Before black start, all switches except the fourth switch K4, the thirteenth switch K13, the fourteenth switch K14, and the fifteenth switch K15 are closed; when the AC grid InP in the station loses power, the first bus B1 can be detected to be de-energized, and the first switch K1 and the tenth switch K10 are disconnected by the station's islanding protection; the automatic transfer switch can control the first type of electrical equipment 130 to switch to the external power supply OutP, that is, the fifth switch K5, the sixth switch K6, and the seventh switch K7 are disconnected, and the thirteenth switch K13, the fourteenth switch K14, and the fifteenth switch K15 are closed; when both the main power supply and the external power supply OutP lose power, the first bus B1 and the third bus B3 can be detected to be de-energized, and the first switch K1 and the tenth switch K10 are disconnected by the station's islanding protection. This automatic transfer switch can be based on the voltage transformers on the bus (Potential If the voltage data detected by the Transformer (PT) determines that both the first busbar B1 and the third busbar B3 are undervoltage, it can automatically disconnect the third switch K3 and the first busbar switch QF1, and close the fourth switch K4 on the line where the external power supply is located. This allows the first type of electrical equipment 130 to operate during a black start of the power system. The power system can then black start the first type of electrical equipment 130 and re-establish the AC side voltage. After determining that the AC side voltage of the power system is normal based on the voltage data obtained from the busbar PT, the automatic standby power supply device closes the tenth switch K10, and after a delay, disconnects the fourth switch K4 on the line where the external power supply is located, or after a delay, disconnects the thirteenth switch K13, the fourteenth switch K14, and the fifteenth switch K15, and then sequentially closes the third switch K3 and the first busbar switch QF1, restoring normal power supply to all stations.
[0093] As shown in Figure 4, the main power supply 110 can be an AC grid InP, with a first switch K1 connected to it. An energy storage system ESS can be connected in parallel to the AC grid InP, with a tenth switch K10 connected to the ESS. A first transformer can be installed between the AC grid InP and the first bus B1, with switches on both sides of the first transformer, namely a second switch K2 and a third switch K3. The first backup power supply 120 can be an off-site power supply OutP, with a second transformer installed between the off-site power supply OutP and the third bus B3. Switches can also be installed on both sides of this second transformer, namely an eleventh switch K11 and a twelfth switch K12.
[0094] The AC power grid InP can be used to supply power to various electrical devices. The first busbar B1 can be used to connect to the first type of electrical equipment 130. In the example shown in Figure 4, the first type of electrical equipment 130 includes valve cooling, fire protection, and HVAC systems. The first busbar B1 can connect to three branches, which are used to connect to the valve cooling, fire protection, and HVAC systems respectively. Each of the three branches is equipped with a switch: the fifth switch K5, the sixth switch K6, and the seventh switch K7. The third busbar B3 can be connected to the first busbar B1 via the second busbar switch QF2.
[0095] The AC power grid InP can also be connected to a second busbar B2, which is connected to the first busbar B1 via a first busbar switch QF1. The second busbar B2 is used to connect a second type of electrical equipment 140, and the line containing the second type of electrical equipment 140 can be connected to a ninth switch K9. When the first busbar switch QF1 is closed, the first busbar B1 and the second busbar B2 can be connected, and the AC power grid InP can supply power to the electrical equipment connected to the first busbar B1 and the electrical equipment connected to the second busbar B2.
[0096] In the example shown in Figure 4, the second backup power supply 150 can be an external power supply, which can be connected to a branch of the first busbar B1, on which a fourth switch K4 can be installed.
[0097] As shown in Figure 5, based on the implementation of the power system shown in Figure 4, its specific control logic can be expressed as follows: Before the black start of the power system, except for the fourth switch K4 and the second bus switch QF2 which are open, all other switches are in the closed state; when the AC power grid InP in the station loses power, the first bus B1 can be detected to be undervoltage, and the first switch K1 and the tenth switch K10 are disconnected by the islanding protection in the station. Based on the voltage data obtained by the standby power supply automatic transfer device from the bus PT, it is determined that the first bus B1 is undervoltage and the third bus B3 is normal. In this case, the third switch K3 and the first bus switch QF1 are automatically disconnected, and the second bus switch QF2 is closed, so that the external power supply OutP can be used to supply power to the first type of electrical equipment 130 during the black start. When both the AC power grid InP within the station and the external power supply OutP lose power simultaneously, the first switch K1 and the tenth switch K10 are disconnected by the station's islanding protection. Based on the voltage data obtained from the bus PT, the automatic transfer switch determines that the first bus B1 and the third bus B3 are both undervoltage. It then automatically disconnects the third switch K3 and the first bus switch QF1, and closes the fourth switch K4 on the line where the external power supply is located, allowing the external power supply OutP to supply power to the first-class electrical equipment 130 during black start. The power system can then black start the first-class electrical equipment 130, re-establishing the AC side voltage. After determining that the AC side voltage of the power system is normal based on the voltage data obtained from the bus PT, the automatic transfer switch closes the tenth switch K10, delays before disconnecting the fourth switch K4 or the second bus switch QF2 on the line where the external power supply is located, and then sequentially closes the third switch K3 and the first bus switch QF1, restoring normal power supply to all station components.
[0098] Through the above implementation method, the busbars provided by the station's AC power grid InP and the energy storage system ESS are designed in segments. The first busbar B1 is used to connect the first type of electrical equipment 130, and the second busbar B2 is used to connect the second type of electrical equipment 140. During black start, some backup power sources can supply power to the necessary first type of electrical equipment 130, which can improve the safety of the power system during black start. Furthermore, by temporarily not supplying power to the second type of electrical equipment during black start, black start can be better realized, the success rate of black start can be improved, and the burden during black start can be reduced.
[0099] Please refer to Figure 6, which is a flowchart of the black-start method provided in this embodiment. The black-start method provided in this embodiment can be applied to the aforementioned power system, through which the steps of the black-start method are executed. The specific process shown in Figure 6 will be described in detail below.
[0100] Step 210: If the main power supply fails, disconnect the main power supply from the first type of electrical equipment and disconnect the main power supply from the second type of electrical equipment.
[0101] For example, the voltage of the first bus connected to the main power supply is monitored by a first backup power automatic switching device.
[0102] If the main power supply is found to be out of power based on the voltage of the first bus, the connection between the main power supply and the first type of electrical equipment is disconnected, and the connection between the main power supply and the second type of electrical equipment is disconnected, through the automatic switching device of the first backup power supply.
[0103] Step 220: Control the connection between the first type of electrical equipment and the first backup power supply, and use the first backup power supply to supply power to the first type of electrical equipment during the black start of the power system.
[0104] The first type of electrical equipment is connected to the first backup power supply through the automatic switching device of the first backup power supply.
[0105] Step 230: After monitoring that the voltage of the bus where the main power supply is located has returned to normal, connect the main power supply to the first type of electrical equipment and connect the main power supply to the second type of electrical equipment.
[0106] In another scenario, both the main power supply and the first backup power supply may fail. Based on this, as shown in Figure 7, the black-start method may further include steps 240 to 260.
[0107] Step 240: If both the main power supply and the first backup power supply are found to be out of power, disconnect the main power supply from the first type of electrical equipment and disconnect the main power supply from the second type of electrical equipment.
[0108] For example, the first voltage of the first bus connected to the main power supply and the second voltage of the third bus connected to the first backup power supply are monitored by the first backup power supply automatic switching device.
[0109] When it is determined, based on the first voltage of the first bus and the third voltage of the third bus, that both the main power supply and the first backup power supply are de-energized, the connection between the main power supply and the first type of electrical equipment is disconnected, and the connection between the main power supply and the second type of electrical equipment is disconnected, through the automatic switching device of the first backup power supply.
[0110] Step 250: Control the connection between the first type of electrical equipment and the second backup power supply, and use the second backup power supply to supply power to the first type of electrical equipment during the black start of the power system.
[0111] For example, the connection between the first type of electrical equipment and the second backup power supply is controlled by a second backup power automatic switching device.
[0112] Step 260: After monitoring that the voltage of the bus where the main power supply is located has returned to normal, connect the main power supply to the first type of electrical equipment and connect the main power supply to the second type of electrical equipment.
[0113] The method provided in this application is applied to the power system provided in the foregoing embodiments. Further steps that this method can perform can be found in the functional steps that the power system in the foregoing embodiments can achieve, and will not be repeated here.
[0114] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0115] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. An electric power system, comprising: The main power supply is connected to a first busbar and a second busbar; the first busbar is used to connect a first type of electrical equipment, and the main power supply is connected to the first type of electrical equipment through a first switch group; the second busbar is used to connect a second type of electrical equipment, and the main power supply is connected to the second type of electrical equipment through a second set of switches. The first backup power supply is connected to the third busbar; the third busbar is used to connect the first type of electrical equipment, and the first backup power supply and the first type of electrical equipment are connected through a third set of switches. The main power supply is used to supply power to the first type of electrical equipment and the second type of electrical equipment; in the event of a power failure of the main power supply, the first backup power supply is used to supply power to the first type of electrical equipment during the black start of the power system.
2. The power system of claim 1, wherein, Also includes: An automatic backup power supply device connected to the first busbar and the third busbar is used to switch the first type of electrical equipment to the first busbar or the third busbar based on the obtained voltage of the first busbar and the third busbar, so as to switch the main power supply or the first backup power supply to supply power to the first type of electrical equipment.
3. The power system of claim 2, wherein, Also includes: The first busbar connects to multiple branches, and each branch is used to connect one or more Class I electrical devices; The third busbar connects to multiple branches, each branch being used to connect one or more Class I electrical devices, wherein the number of branches of the first busbar is the same as the number of branches of the third busbar; Each branch of the first busbar and its corresponding branch of the third busbar are equipped with a first backup power automatic switching device, which is used to switch the connection of the first type of electrical equipment connected to the branch to the first busbar or the third busbar.
4. The power system of claim 1, wherein, The first switch group includes a switch connected between the first busbar and the main power supply, and a switch connected between the first busbar and the first type of electrical equipment.
5. The power system of claim 1, wherein, The third set of switches includes a switch connected between the third busbar and the first backup power supply, and a switch connected between the third busbar and the first type of electrical equipment.
6. The power system of claim 1, wherein, The first switch group includes a switch connected between the first busbar and the main power supply, and a switch connected between the first busbar and the first type of electrical equipment; The third set of switches includes a switch connected between the third busbar and the first backup power supply, a switch for connecting the first busbar and the third busbar, and a switch shared with the first set of switches for connecting between the first busbar and the first type of electrical equipment.
7. The power system of claim 1, wherein, The first switch group includes a switch connected between the first busbar and the main power supply, and a switch connected between the first busbar and the first type of electrical equipment; The second set of switches includes a switch shared with the first set of switches that connects the first busbar to the main power supply, a switch for connecting the first busbar to the second busbar, and a switch for connecting the second busbar to the second type of electrical equipment.
8. The power system of any of claims 1-7, wherein, Also includes: A second backup power supply connected to a branch of the first busbar, and a switch connected to the branch where the second backup power supply is located; When the switch on the branch where the second backup power source is located is closed, the second backup power source supplies power to the first type of electrical equipment.
9. The power system of claim 8, wherein, Also includes: An automatic switching device for the second backup power supply, installed at the switch on the branch where the second backup power supply is located, is used to control the closing and opening of the switch on the branch where the second backup power supply is located based on the power failure status of the main power supply and the first backup power supply.
10. The power system of any of claims 1-7, wherein, It also includes an energy storage system connected to the first busbar, and a switch is connected between the energy storage system and the first busbar.
11. The power system of any of claims 1-7, wherein, The electrical equipment in the first category is the safety equipment in the power system.
12. A black start method for a power system, applied to the power system according to any one of claims 1-11, the black start method comprising: If a power failure is detected in the main power supply, disconnect the main power supply from the first type of electrical equipment and disconnect the main power supply from the second type of electrical equipment. Control the connection between the first type of electrical equipment and the first backup power supply, and use the first backup power supply to supply power to the first type of electrical equipment during the black start of the power system; When the voltage of the bus where the main power supply is located is detected to return to normal, the connection between the main power supply and the first type of electrical equipment is established, and the connection between the main power supply and the second type of electrical equipment is established.
13. The method of claim 12, wherein, Also includes: If both the main power supply and the first backup power supply are found to be out of power, disconnect the main power supply from the first type of electrical equipment and disconnect the main power supply from the second type of electrical equipment. Control the connection between the first type of electrical equipment and the second backup power supply, and use the second backup power supply to supply power to the first type of electrical equipment during the black start of the power system; When the voltage of the bus where the main power supply is located is detected to return to normal, the connection between the main power supply and the first type of electrical equipment is established, and the connection between the main power supply and the second type of electrical equipment is established.
14. The method of claim 13, wherein, When both the main power supply and the first backup power supply are detected to be out of power, disconnecting the main power supply from the first type of electrical equipment and disconnecting the main power supply from the second type of electrical equipment includes: The first voltage of the first bus connected to the main power supply and the second voltage of the third bus connected to the first backup power supply are monitored by the first backup power supply automatic switching device. If it is determined that both the main power supply and the first backup power supply are out of power based on the first voltage of the first bus and the third voltage of the third bus, the main power supply is disconnected from the first type of electrical equipment and the main power supply is disconnected from the second type of electrical equipment by the automatic switching device of the first backup power supply. The control connection between the first type of electrical equipment and the second backup power supply includes: The first type of electrical equipment is connected to the second backup power supply through the automatic switching device for the second backup power supply.
15. The method of claim 12, wherein, In the event of a detected power failure of the main power supply, disconnecting the main power supply from the first type of electrical equipment and disconnecting the main power supply from the second type of electrical equipment includes: The voltage of the first bus connected to the main power supply is monitored by the first backup power automatic switching device. If the main power supply is found to be out of power based on the voltage of the first bus, the connection between the main power supply and the first type of electrical equipment is disconnected, and the connection between the main power supply and the second type of electrical equipment is disconnected, through the first backup power automatic switching device. The control connection between the first type of electrical equipment and the first backup power supply includes: The first type of electrical equipment is connected to the first backup power supply through the first backup power automatic switching device.