Electrical network system and method for operating electrical network system

Abstract

The invention provides a power grid system and a method for controlling the power grid system. According to the invention, an electrical network system is provided. The power grid system is suitable for providing power to at least one load unit and comprises a bus, a switch module and an energy storage system coupled to the bus. The at least one load unit is coupled to the bus. The switch module comprises a switch device which is connected between the bus and the main power grid. The energy storage system is configured to operate in a current source mode and a voltage source mode, and is configured to receive a trip signal from the switch module. The energy storage system is configured to switch to a voltage source mode when the energy storage system receives a trip signal.

Description

Technical Field

[0001] The technical field of the present invention relates to a power grid system and a method for controlling the power grid system; more specifically, to a power grid system that achieves a grid-connected mode and a standalone mode and a method for controlling the power grid system. Background Art

[0002] A grid system that includes a group of loads and distributed energy sources located in a specific area and can operate as a single controllable entity can be considered a microgrid. The loads can be utility "customers", a grouping of several sites, or distributed sites operating in a coordinated manner. Distributed energy sources can include reciprocating engine generators, microturbines, fuel cells, photovoltaic / solar and other small-scale renewable power generation devices.

[0003] The microgrid can operate in either a grid-connected mode or an off-grid mode. Under normal circumstances, the microgrid operates in a grid-connected mode. In the grid-connected mode, the microgrid is connected to the main grid, which serves as the voltage source for the microgrid. When an accident occurs in the main grid, the microgrid can be disconnected from the main grid and can be switched to an off-grid mode. In this case, a backup voltage supply device must replace the main grid and serve as a voltage supply source to stabilize the voltage of the microgrid.

[0004] In some cases, when switching to off-grid mode, the generator can be used as a backup voltage supply device. However, the startup of the generator may cause a delay in the voltage source switching. The time delay may cause the terminal load to trip or fail due to the sudden voltage drop. Therefore, an improved power grid system with shorter time delay and a method for controlling the power grid system are desirable. Summary of the invention

[0005] The present invention provides a power grid system suitable for providing power to at least one load unit. The power grid system includes a bus, a switch module and an energy storage system coupled to the bus. At least one load unit is coupled to the bus. The switch module includes a switch device, which is connected between the bus and the main power grid. The energy storage system is configured to operate in a current source mode and a voltage source mode, and is configured to receive a trip signal from the switch module. The energy storage system is configured to switch to a voltage source mode when the energy storage system receives the trip signal.

[0006] In one embodiment, the trip signal is a feedback signal from the switching device.

[0007] In one embodiment, the energy storage system and the switch module are coupled by one or more cables, and the trip signal is transmitted to the energy storage system via the one or more cables.

[0008] In one embodiment, the energy storage system is configured to receive a closing signal from the switch module and is configured to switch from the voltage source mode to the current source mode when the energy storage system receives the closing signal.

[0009] In one embodiment, the closing signal is a feedback signal from the switching device.

[0010] In one embodiment, the energy storage system and the switch module are coupled by one or more cables, and the closing signal is transmitted to the energy storage system via the one or more cables.

[0011] In one embodiment, the energy storage system is configured to receive a multiplexing instruction signal from the control system and is configured to synchronize the power grid system with the main power grid when the energy storage system receives the multiplexing instruction signal.

[0012] In one embodiment, the grid system further includes a voltage sensing unit configured to measure the voltage of the main grid and provide a voltage signal to the energy storage system.

[0013] In one embodiment, the energy storage system is configured to determine whether the power grid system is synchronized with the main power grid according to the voltage signal.

[0014] In one embodiment, the energy storage system is configured to send a startup instruction signal when the energy storage system determines that the power grid system is synchronized with the main power grid.

[0015] In one embodiment, the energy storage system is configured to send a switching instruction signal to the switch module.

[0016] In one embodiment, the switch module further includes an intelligent electronic device (IED), which is coupled to the switch device and configured to initiate a startup operation of the switch device, and the energy storage system is configured to send a startup instruction signal to the intelligent electronic device.

[0017] In an embodiment, the intelligent electronic device is configured to trip the switching device.

[0018] In an embodiment, the switch device comprises a contact switch.

[0019] In one embodiment, the power grid system further includes at least one distributed power generation device coupled to the busbar.

[0020] In one embodiment, the power grid system further includes a transformer, wherein the transformer includes a first coil coupled to the switch device and a second coil coupled to the busbar.

[0021] The present invention provides a method for controlling a power grid system, the power grid system comprising a switch module and an energy storage system and being suitable for supplying power to at least one load unit via a bus. The switch module comprises a switch device connected between the bus and an external main power grid. The energy storage system is coupled to the bus. The method comprises tripping the switch device, receiving a trip signal from the switch module by the energy storage system; and switching the operation mode of the energy storage system from a current source mode to a voltage source mode when the energy storage system receives the trip signal.

[0022] In one embodiment, the trip signal is a feedback signal from the switching device.

[0023] In one embodiment, the energy storage system and the switch module are coupled by one or more cables, and the method includes transmitting a trip signal to the energy storage system via the one or more cables.

[0024] In one embodiment, the method further includes turning on the switch device, receiving a closing signal from the switch module by the energy storage system, and switching the operation mode of the energy storage system from the voltage source mode to the current source mode when the energy storage system receives the closing signal.

[0025] In one embodiment, the closing signal is a feedback signal from the switching device.

[0026] In one embodiment, the energy storage system and the switch module are coupled by one or more cables, and the method includes transmitting a closing signal to the energy storage system via the one or more cables.

[0027] In one embodiment, the method further includes synchronizing the power grid system with the main power grid when the energy storage system receives a reconnection instruction signal from the control system.

[0028] In one embodiment, the method further includes measuring the voltage of the main grid using a voltage sensing unit and providing a voltage signal to the energy storage system.

[0029] In one embodiment, the method further comprises using the energy storage system to determine whether the main power grid has been repaired based on the voltage signal.

[0030] In one embodiment, the method further comprises using the energy storage system to determine whether the power grid system is synchronized with the main power grid according to the voltage signal.

[0031] In one embodiment, switching on the switch device includes sending a switching instruction signal from the energy storage system to the switch module.

[0032] In one embodiment, the method includes sending a startup instruction signal when the energy storage system determines that the power grid system is synchronized with the main power grid.

[0033] In one embodiment, the switch module includes an intelligent electronic device (IED) coupled to the switch device, and switching on the switch device includes sending a switching command signal from the energy storage system to the IED and using the IED to initiate a switching operation of the switch device.

[0034] In one embodiment, tripping the switching device includes opening contacts of the switching device. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a block diagram of a power grid system according to an embodiment of the present disclosure;

[0036] Figure 2 is a block diagram of a power grid system switched to an off-grid mode according to an embodiment of the present disclosure;

[0037] Figure 3 is a flow chart of a method for controlling a power grid system according to an embodiment of the present disclosure;

[0038] Figure 4 is a block diagram of a power grid system switched to a grid-connected mode according to an embodiment of the present disclosure;

[0039] Figure 5 is a flow chart of a method for controlling a power grid system according to an embodiment of the present disclosure.

[0040] Description of Reference Numerals

[0041] 100: Power grid system

[0042] 102: Busbar

[0043] 104: Switch module

[0044] 1042: Switching device

[0045] 1044: Intelligent Electronic Device (IED)

[0046] 1044I: Digital input port

[0047] 1044O: Digital output port

[0048] 1046: voltage sensing unit

[0049] 105: High voltage feeder

[0050] 106: Energy Storage System

[0051] 107A,107B: Cable

[0052] 108A: Photovoltaic / solar power generation devices

[0053] 108B: Diesel generator

[0054] 109: Transformer

[0055] 1092: First coil

[0056] 1094: Second coil

[0057] 300,500:Method

[0058] 310,320,330,340,350,510,520,530,540,550,560:Step 50:Main Power Grid

[0059] 60: Control System

[0060] DS1: trip signal

[0061] DS2: Multiplexing command signal

[0062] DS3: Input command signal

[0063] DS4: Closed signal

[0064] L1, L2, L3, L4: load cells

[0065] VS: voltage signal DETAILED DESCRIPTION

[0066] The following is a detailed description of the embodiments with accompanying drawings, but the embodiments provided are not intended to limit the scope of the present invention, and the description of the operation is not intended to limit the order of its execution. Any structure generated by the re-combination of elements with equal functions is within the scope of the present disclosure. In addition, the drawings are for illustrative purposes only and are not drawn in their original size. For ease of understanding, the same or similar elements in the following description will be indicated by the same symbols.

[0067] The terms used throughout the specification and claims, unless otherwise noted, generally have their ordinary meaning in the art, in the context of the present disclosure, and in the specific context in which the term is used. Certain terms used to describe the present disclosure will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the present disclosure.

[0068] In addition, the words "include", "comprising", "having", "containing", etc. used in this article are all open terms, that is, they mean "including but not limited to". In addition, "and / or" used in this article includes any one or more items in the relevant enumerated items and all combinations thereof.

[0069] In this document, when an element is referred to as "coupled", it may refer to "electrically coupled", and when referred to as "connected", it may refer to "electrically connected". "Connected" and "coupled" may also be used to indicate that two or more elements operate or interact with each other. In addition, although the terms "first", "second", etc. are used in this document to describe multiple elements, the terms are only used to distinguish one element from another, and are not used to limit the present invention. For example, a first element may be referred to as a second element, and, similarly, a second element may be referred to as a first element without departing from the scope of the embodiment.

[0070] Figure 1 is a block diagram of a power grid system according to an embodiment of the present disclosure. Figure 1 , providing a power grid system 100. The power grid system 100 may be a microgrid system, which is a regionalized grouping of power generation, energy storage, and loads. The power grid system 100 may include a bus 102 (e.g., an AC bus), a switch module 104, and an energy storage system 106. The bus 102 may be coupled to a main grid 50, such as a traditional centralized grid, a "macrogrid," or a distribution grid, so that the power grid system 100 may be connected to the main grid 50 and powered by the main grid 50. The power grid system 100 is adapted to supply power to at least one load unit, such as a load unit L1, a load unit L2, a load unit L3, and a load unit L4. Each of the load units L1, L2, L3, and L4 may be directly or indirectly coupled to the bus 102. The load units L1, L2, L3, and L4 may be general loads or critical loads. The number of load cells is merely an example and is not limiting.

[0071] The power grid system 100 may further include at least one distributed power generation device. The distributed power generation device may be a photovoltaic / solar power generation device 108A or a diesel power generation device 108B. The distributed power generation device may also be a reciprocating engine power generation device, a micro-turbine power generation device, a fuel cell, a wind turbine power generation device, a hydroelectric power generation device, other small-scale renewable energy power generation devices, and the like. Figure 1 As shown, distributed power generation devices 108A and 108B are coupled to bus 102 and can provide power to load units L1, L2, L3, and L4 via bus 102. The number of distributed power generation devices is only an example and is not limiting.

[0072] The energy storage system 106 may include a direct current to alternating current (DC / AC) converter and a plurality of storage cells, for example, lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, sodium-sulfur cells, lithium batteries or fuel cells. The types of batteries are not limited to those listed in this embodiment. The energy storage system 106 may also include a supercapacitor or a flywheel. In some embodiments, at least one of the DC / AC converters may be a three-phase converter. The energy storage system 106 may be coupled to the bus 102. The energy storage system 106 may be used to provide stable power to the load units L1, L2, L3 and L4. For example, during periods of excess power generation, the energy storage system 106 can be charged by the distributed power generation device 108A, and when the power generation from the distributed power generation device 108A (and the distributed power generation device 108B) is low, such as at night or on cloudy days (in the case of solar energy), or when the power demand from the load units L1, L2, L3 and L4 is high, the energy storage system 106 can provide additional power.

[0073] The energy storage system 106 may further include processing circuits (which may include digital and / or analog circuits, such as one or more controllers, processors, application-specific integrated circuits (ASICs), etc.) to execute program code that implements one or more procedures described herein. The energy storage system 106 may also include one or more storage media, such as random access memory (RAM), read-only memory (ROM), hard drive storage, temporary storage, volatile memory, flash memory, optical storage, or any other suitable memory for storing program code and related data processed and accessed by the processing circuits during execution of the program code. The storage medium may also store results generated by the energy storage system 106.

[0074] The switch module 104 may include a switch device 1042. In some embodiments, the switch device 1042 may include a contact switch, such as a circuit breaker, such as an oil circuit breaker, a gas blow circuit breaker, a sulfur hexafluoride (SF 6 ) circuit breaker, vacuum circuit breaker, miniature circuit breaker (MCB), molded case circuit breaker (MCCB), and the like. The switch device 1042 may further include an operating mechanism for a closing operation and a tripping operation of the switch device 1042. However, the present disclosure is not limited thereto. Figure 1 As shown, the switch device 1042 is connected between the bus 102 and the main power grid 50. Figure 1As shown, the switch device 1042 can be connected to the high voltage feeder 105 of the main grid 50. The switch device 1042 can be configured to selectively allow current to flow between the bus 102 and the main grid 50, so that the grid system 100 can be separated from the main grid 50 by opening at least the switch device 1042.

[0075] In detail, the power grid system 100 is configured to be connected to the main power grid 50 in the grid-connected mode and to be separated from the main power grid 50 (in some cases, the main power grid 50 and other power grids) in the off-grid mode. By connecting / disconnecting the switch device 1042, the power grid system 100 can realize the grid-connected mode and the off-grid mode.

[0076] like Figure 1 As shown, when the power grid system 100 operates in the grid-connected mode, the switch device 1042 is in the turned-on state. In this case, the energy storage system 106 can be charged by at least one of the distributed power generation devices (e.g., the distributed power generation device 108A) and / or the main grid 50; or, in some cases, the energy storage system 106 can operate in a current source mode, in which the operation of the energy storage system 106 is similar to a current source. The energy storage system 106 can refer to the voltage and frequency of the power grid system 100 (e.g., the voltage and frequency of the bus 102) or the voltage and frequency of the main grid 50, and the power generated by the energy storage system 106 is supplied to the power grid system 100 to supply power to the load units L1, L2, L3 and L4.

[0077] In the grid-connected mode, when an accident occurs in the main grid 50 or other regional grids connected to the main grid 50, the switch device 1042 may trip. The switch device 1042 is therefore in a turned-off state and the grid system 100 may operate in an off-grid mode. In this case, the energy storage system 106 may operate in a voltage source mode, in which the energy storage system 106 serves as a voltage source for supplying the grid system 100. The energy storage system 106 may supply power to the load units L1, L2, L3, and L4 and may establish a bus voltage on the bus 102 for the distributed power generation devices 108A and 108B.

[0078] The switch module 104 may further include an intelligent electronic device (IED) 1044 coupled to the switch device 1042. The intelligent electronic device 1044 may be configured to measure electrical characteristics of the power flowing through the switch device 1042 and use the measured results to determine the occurrence of an accident. In some embodiments, the intelligent electronic device 1044 is configured to trip the switch device 1042.

[0079] like Figure 1 As shown, the power grid system 100 may further include a voltage sensing unit 1046. The voltage sensing unit 1046 is configured to measure the voltage of the main grid 50 and provide a voltage signal VS to the energy storage system 106. In one embodiment, the voltage sensing unit 1046 may be a voltmeter or a potential transformer (PT), the high voltage side of the potential transformer is connected to the main grid 50 (e.g., the high voltage feeder 105 of the main grid 50) and the voltmeter is connected to the low voltage side of the potential transformer to measure the proportional voltage of the main grid 50.

[0080] like Figure 1 As shown, the power grid system 100 may also include a transformer 109. For example, the switch module 104 may be located in a substation, and the substation may include a transformer 109 that reduces the voltage to a distribution voltage, and one or more distribution buses (such as bus 102) may spread this reduced distribution voltage in multiple directions. The switch device 1042 may be configured to disconnect the substation (or part thereof) and the rest of the power grid system 100 from the main power grid 50 or to disconnect one or more distribution lines from the substation. The transformer 109 may include a first coil 1092 and a second coil 1094. As shown in FIG. Figure 1 As shown, first coil 1092 is coupled to switch device 1042, and second coil 1094 is coupled to bus 102. Switch device 1042 may be configured to isolate the remainder of grid system 100 from main grid 50 to initiate an off-grid mode of grid system 100. However, the present disclosure is not limited thereto.

[0081] although Figure 1 The power grid system 100 is shown in a single line diagram, and the power grid system 100 can be configured to transmit single-phase or multi-phase power. Although the power grid system 100 is an AC power system, other embodiments may include a DC power system, such as a DC (DC) distribution system. In addition, it should be understood that the layout of the power grid system 100 is shown for explanation purposes and is not intended to be a limitation of the present disclosure.

[0082] Figure 2is a block diagram of a power grid system switched to an off-grid mode according to an embodiment of the present disclosure. Figure 2 As shown, the switch device 1042 is tripped. As mentioned above, the switch device 1042 may be driven to trip by the intelligent electronic device 1044. In some embodiments, the switch device 1042 may be remotely controlled by a control system (e.g., a Supervisory Control and Data Acquisition (SCADA) system). In some embodiments, the switch device 1042 may be tripped due to an accident in the main power grid 50 or other power grids connected to the main power grid 50.

[0083] The energy storage system 106 described herein may be configured to receive a trip signal DS1 from the switch module 104. In some embodiments, the trip signal DS1 is a feedback signal from the switch device 1042. In detail, the switch device 1042 may be configured to output a status signal. The status signal may be a feedback signal, such as a trip feedback signal (TRIPPED), an on / off feedback signal (On / Off), a closed feedback signal (CLOSED), etc., or a combination thereof, which indicates the operating state of the switch device (e.g., a circuit breaker). In some embodiments, the switch device 1042 may include a control finite state machine (control FSM) configured to output the feedback signal. The feedback signal may be a digital signal. However, the present disclosure is not limited thereto. In some embodiments, the trip signal may be a signal from an intelligent electronic device 1044. The energy storage system 106 may be configured to receive a signal from the switch module 104. The energy storage system 106 may include a receiving card so that the energy storage system 106 can receive a signal from the switch module 104 and operate accordingly. For example, the energy storage system 106 may be configured to receive a trip feedback signal (TRIPPED) and / or an on / off feedback signal (On / Off). However, the present disclosure is not limited thereto.

[0084] The energy storage system 106 described herein may be further configured to switch to a voltage source mode when the energy storage system 106 receives the trip signal DS1. As described above, the energy storage system 106 is configured to operate in a current source mode and a voltage source mode. For example, when the power grid system 100 operates in a grid-connected mode, the energy storage system 106 may operate in a current source mode. The energy storage system 106 described herein may be configured to switch from a current source mode to a voltage source mode when the energy storage system 106 receives the trip signal DS1, for example, through a processing circuit and / or a switch module in the energy storage system 106.

[0085] By means of the configuration described herein, the energy storage system 106 can complete the switching to the voltage source mode and provide the bus voltage to the load units L1, L2, L3 and L4 and the distributed power generation devices 108A and 108B in a relatively short time. In this way, the load units L1, L2, L3 and L4 can be continuously powered by the power grid system 100. Furthermore, since the distributed power generation devices 108A and 108B can also be continuously powered by the power grid system 100, the distributed power generation devices 108A and 108B can continuously generate electrical energy to the power grid system 100. Therefore, even during the period when the power grid system 100 is switched from the grid-connected mode to the off-grid mode, the power grid system 100 can continuously supply power without interruption. In addition, the energy storage system 106 described herein can be configured to operate according to the feedback signal from the switch device 1042, so no additional calculation or signal processing is required, and the conversion of the energy storage system 106 can be performed without further delay. It should be noted that during the conversion of the energy storage system 106 , the residual voltage on the bus 102 can continue to supply power to the load units L1 , L2 , L3 and L4 and the distributed power generation devices 108A and 108B for a certain period of time.

[0086] like Figure 2 As shown, in some embodiments, the energy storage system 106 and the switch module 104 are coupled by one or more cables. The cable may include an electrical cable, an optical fiber cable, a power line, etc., or a combination thereof. In some embodiments, the trip signal DS1 may be transmitted to the energy storage system 106 via the one or more cables (e.g., cable 107A). Through the configuration described herein, the energy storage system 106 can directly receive the trip signal DS1 from the switch device 1042 without transmitting the signal to a third device (e.g., a control system, such as a SCADA system) and / or having the third device process the signal, so that the reception of the trip signal DS1 and the switching of the operating mode can be performed without further delay.

[0087] Figure 3 According to an embodiment of the present disclosure, a method for controlling a power grid system (eg Figure 1 and Figure 2 100) is a flowchart of a method of the power grid system 100 shown in FIG. Figure 2 and Figure 3 , the power grid system 100 may include a switch module 104 and an energy storage system 106. The power grid system 100 may be adapted to supply power to at least one load unit (e.g., load units L1, L2, L3, and L4) through a bus 102. The switch module 104 may include a switch device 1042. The switch device 1042 may be connected between the bus 102 and the main power grid 50. The energy storage system 106 is coupled to the bus 102.

[0088] The method 300 includes tripping the switch device 1042 (step 310). In some embodiments, the switch device 1042 may be a contact switch and tripping the switch device 1042 may include opening a contact of the switch device 1042. The method 300 includes receiving a trip signal (e.g., a trip signal DS1) from the switch module 104 by the energy storage system 106 if the switch device 1042 is tripped (e.g., due to an accident in the main power grid 50) (step 320). The method 300 includes switching the operation mode of the energy storage system 106 from the current source mode (or in some cases, from other operation modes) to the voltage source mode when the energy storage system 106 receives the trip signal DS1 (step 330). The method 300 may also include supplying power to at least one load unit (e.g., load units L1, L2, L3, and L4) in an off-grid mode of the power grid system 100 (step 340). In the method 300 , if the switch device 1042 is not tripped, the energy storage system 106 may not receive the trip signal DS1 , and the energy storage system 106 maintains its current operation mode (step 350 ).

[0089] Figure 4 FIG. 1 is a block diagram of a power grid system switched to a grid-connected mode according to an embodiment of the present disclosure. Figure 4 As shown, the power grid system 100 is still operating in the off-grid mode, and the switch device 1042 is in the off state. The switch device 1042 may be in a ready to close state. In some embodiments, the energy storage system 106 may receive a ready to close feedback signal (RTC) from the switch device 1042. However, the present disclosure is not limited thereto.

[0090] The energy storage system 106 may be configured to receive a reconnection command signal DS2 from the control system 60. Specifically, in some embodiments, the control system 60 may perform a restoration switching analysis (RSA) to determine a service restoration switching plan. The control system 60 may send one or more command signals (e.g., the reconnection command signal DS2) to activate the switch device 1042 to reconnect the power grid system 100 to the main power grid 50.

[0091] In some embodiments, the energy storage system 106 is configured to synchronize the power grid system 100 (or the energy storage system 106) with the main power grid 50. In detail, in the off-grid mode, the power grid system 100 may operate at a frequency and voltage different from that of the main power grid. The energy storage system 106 may be configured to control and adjust the frequency, voltage magnitude and phase angle of the power grid system 100 to match the frequency, voltage magnitude and phase angle of the main power grid 50. The energy storage system 106 may be configured to synchronize the power grid system 100 with the main power grid 50 when the energy storage system 106 receives the multiplexing instruction signal DS2.

[0092] In some embodiments, the energy storage system 106 is configured to determine whether the power grid system 100 is synchronized with the main power grid 50. Figure 1 The power grid system 100 may further include a voltage sensing unit 1046, which measures the voltage of the main grid 50 and provides a voltage signal VS to the energy storage system 106. The energy storage system 106 may be configured to receive the voltage signal VS and determine whether the power grid system 100 is synchronized with the main grid 50 according to the voltage signal VS. When the power grid system 100 is synchronized with the main grid 50, the energy storage system 106 may perform phase locking.

[0093] like Figure 4 As shown, the energy storage system 106 may be further configured to send a closing command signal DS3 when the energy storage system 106 determines that the power grid system 100 is synchronized with the main power grid 50. The energy storage system 106 may be configured to send the closing command signal DS3 to the switch module 104. In an embodiment where the switch module 104 further includes an intelligent electronic device 1044, the intelligent electronic device 1044 may be configured to start the closing operation of the switch device 1042, and the energy storage system 106 is configured to send the closing command signal DS3 to the intelligent electronic device 1044 (for example, via the cable 107B). In detail, in some embodiments, when the intelligent electronic device 1044 is configured to output a start-up signal from the digital output port 1044O of the intelligent electronic device 1044 to start the start-up operation of the switch device 1042, the energy storage system 106 is configured to send the start-up instruction signal DS3 to the digital input port 1044I of the intelligent electronic device 1044, instead of sending the start-up instruction signal DS3 directly to the switch device 1042. In the case where the switch device 1042 is a high-voltage circuit breaker, the configuration described herein enables the energy storage system 106 to control the start-up operation of the switch device 1042. However, the present disclosure is not limited thereto. In some other embodiments, the start-up instruction signal DS3 can be sent to the switch device 1042 to start the start-up operation of the switch device 1042.

[0094] Regarding the above Figure 2 Similarly, the energy storage system 106 may be configured to receive a closed signal DS4 from the switch module 104. In detail, the switch device 1042 may be configured to output a closed signal DS4, such as a closed feedback signal (CLOSED) and / or an on / off feedback signal (On / Off). The closed signal DS4 may be a feedback signal from the switch device 1042. The energy storage system 106 may include a receiving card to receive the closed signal DS4. The closed signal DS4 may be a digital signal. However, the present disclosure is not limited to this. The energy storage system 106 may be further configured to switch from a voltage source mode to a current source mode when the energy storage system 106 receives the closed signal DS4.

[0095] exist Figure 4 In the embodiment of the invention, the power grid system 100 operates in an off-grid mode, and the energy storage system 106 can operate in a voltage source mode. The energy storage system 106 described herein can be configured to switch from the voltage source mode to the current source mode through, for example, a processing circuit and / or a switch module in the energy storage system 106 when the energy storage system 106 receives the closing signal DS4.

[0096] Regarding the above Figure 2 Similarly, in some embodiments, the energy storage system 106 and the switch module 104 are coupled by one or more cables. In some embodiments, the closing signal DS4 can be transmitted to the energy storage system 106 via the one or more cables, such as cable 107A. In some embodiments, the closing signal DS4 can be transmitted via the same cable as the trip signal DS1. However, the closing signal DS4 can be transmitted via a different cable from the trip signal DS1. With the configuration described herein, the reception of the closing signal DS4 and the switching of the operating mode can be performed without further delay.

[0097] Figure 5 According to an embodiment of the present disclosure, a method for controlling a power grid system (eg Figure 1 , Figure 2 and Figure 4 100) is a flowchart of a method of the power grid system 100 shown in FIG. Figure 4 and Figure 5 In method 500, the main grid 50 may be in a repaired state (step 510). The energy storage system 106 receives the multiplexing instruction signal DS2 from the control system 60 (step 520). The method 500 further includes synchronizing the power grid system 100 with the main grid 50 when the energy storage system 106 receives the multiplexing instruction signal DS2 from the control system 60 (step 530).

[0098] The method 500 may further include determining whether the power grid system 100 is synchronized with the main power grid 50 (step 540). In some embodiments, the method 500 further includes using the voltage sensing unit 1046 to measure the voltage of the main power grid 50 and provide a voltage signal VS to the energy storage system 106, and it can be determined whether the power grid system 100 is synchronized with the main power grid 50 based on the voltage signal VS.

[0099] The method 500 further includes switching on the switch device 1042. Switching on the switch device 1042 may include sending a switching command signal DS3 from the energy storage system 106 to the switch module 104. When the energy storage system 106 determines that the power grid system 100 is synchronized with the main power grid 50, the energy storage system 106 may send the switching command signal DS3. In an embodiment where the switch module 104 further includes an intelligent electronic device (IED) 1044 coupled to the switch device 1042, switching on the switch device 1042 may include sending a switching command signal from the energy storage system 106 to the intelligent electronic device 1044 and using the intelligent electronic device 1044 to start the switching operation of the switch device 1042.

[0100] In some embodiments, the method 500 further includes receiving a closing signal DS4 from the switch module 104 by the energy storage system 106, wherein the closing signal is a feedback signal from the switch device 1042. The method 500 may also include switching the operation mode of the energy storage system 106 from the voltage source mode to the current source mode when the energy storage system 106 receives the closing signal DS4 (step 550).

[0101] In method 500, if the main grid 50 is not repaired, the energy storage system 106 maintains its current operating mode (step 560). In some embodiments, method 500 may further include using the energy storage system 106 to determine whether the main grid 50 is repaired based on the voltage signal VS. In method 500, if the energy storage system 106 does not receive the reconnection instruction signal DS2 from the control system 60, the energy storage system 106 maintains its current operating mode (step 560). In method 500, if the energy storage system 106 determines that the power grid system 100 is not synchronized with the main grid 50, the method 500 continues to synchronize the power grid system 100 with the main grid 50 (step 530).

[0102] The description of the above embodiments can be used by those skilled in the art to implement the inventive subject matter. Various modifications to the embodiments will be apparent to those skilled in the art, and the novel principles and inventive subject matter identified herein can be applied to other embodiments without creative effort. Therefore, the subject matter described in the claims is not limited to the embodiments shown herein, but is consistent with the widest range consistent with the principles and novel features disclosed herein. Other embodiments are conceivable that are also within the spirit and scope of the disclosed subject matter. Therefore, the present disclosure is intended to cover modifications and variations within the scope of the appended claims and their equivalents.

Claims

1. A power grid system, adapted to provide power to at least one load unit, the power grid system comprising: a bus bar, the at least one load unit being coupled to the bus bar; A switch module, comprising a switch device, wherein the switch device is connected between the busbar and the main power grid; and An energy storage system coupled to the bus, the energy storage system being configured to operate in a current source mode and a voltage source mode, and being configured to receive a trip signal from the switch module; The energy storage system is configured to switch to the voltage source mode when the energy storage system receives the trip signal. 2 . The power grid system according to claim 1 , wherein the tripping signal is a feedback signal from the switching device. 3 . The power grid system according to claim 1 , wherein the energy storage system and the switch module are coupled by one or more cables, and the trip signal is transmitted to the energy storage system via the one or more cables. 4 . The power grid system according to claim 1 , wherein the energy storage system is configured to receive a closing signal from the switch module and is configured to switch from the voltage source mode to the current source mode when the energy storage system receives the closing signal.

5. The power grid system according to claim 4, wherein the closing signal is a feedback signal from the switching device. 6 . The power grid system according to claim 4 , wherein the energy storage system and the switch module are coupled by one or more cables, and the closing signal is transmitted to the energy storage system via the one or more cables.

7. The power grid system according to claim 1, wherein the energy storage system is configured to receive a multiplexing instruction signal from a control system and is configured to synchronize the power grid system with the main power grid when the energy storage system receives the multiplexing instruction signal. 8 . The power grid system according to claim 1 , further comprising a voltage sensing unit configured to measure a voltage of the main power grid and provide a voltage signal to the energy storage system. 9 . The power grid system according to claim 8 , wherein the energy storage system is configured to determine whether the power grid system is synchronized with the main power grid based on the voltage signal. 10 . The power grid system according to claim 1 , wherein the energy storage system is configured to send a startup instruction signal when the energy storage system determines that the power grid system is synchronized with the main power grid.

11. The power grid system according to claim 1, wherein the energy storage system is configured to send a switching instruction signal to the switch module.

12. The power grid system according to claim 11, wherein the switch module further comprises an intelligent electronic device, the intelligent electronic device is coupled to the switch device and is configured to initiate a start-up operation of the switch device, and the energy storage system is configured to send the start-up instruction signal to the intelligent electronic device.

13. The power grid system according to claim 12, wherein the intelligent electronic device is configured to trip the switch device.

14. The power grid system of claim 1, wherein the switch device comprises a contactor switch.

15. The power grid system according to claim 1, further comprising at least one distributed power generation device, wherein the distributed power generation device is coupled to the bus.

16. The power grid system of claim 1, further comprising a transformer, wherein the transformer comprises a first coil coupled to the switch device and a second coil coupled to the bus.

17. A method for controlling a power grid system, the power grid system comprising a switch module and an energy storage system and being adapted to supply power to at least one load unit via a bus, the switch module comprising a switch device connected between the bus and a main power grid, the energy storage system being coupled to the bus, the method comprising: causing the switch device to trip; The energy storage system receives a trip signal from the switch module; and When the energy storage system receives the trip signal, the operation mode of the energy storage system is switched from the current source mode to the voltage source mode.

18. The method of claim 17, wherein the trip signal is a feedback signal from the switching device.

19. The method of claim 17, wherein the energy storage system and the switch module are coupled by one or more cables, and the method comprises transmitting the trip signal to the energy storage system via the one or more cables.

20. The method according to claim 17, further comprising: Putting the switch device into operation; The energy storage system receives a closing signal from the switch module; and When the energy storage system receives the closing signal, the operation mode of the energy storage system is switched from the voltage source mode to the current source mode.

21. The method of claim 20, wherein the closing signal is a feedback signal from the switching device.

22. The method of claim 20, wherein the energy storage system and the switch module are coupled by one or more cables, and the method includes transmitting the closing signal to the energy storage system via the one or more cables.

23. The method according to claim 17, further comprising synchronizing the power grid system with the main power grid when the energy storage system self-control system receives a reconnection instruction signal. 24 . The method according to claim 17 , further comprising using a voltage sensing unit to measure a voltage of the main grid and provide a voltage signal to the energy storage system.

25. The method according to claim 24, further comprising using the energy storage system to determine whether the main power grid has been repaired based on the voltage signal.

26. The method according to claim 24, further comprising using the energy storage system to determine whether the power grid system is synchronized with the main power grid based on the voltage signal.

27. The method according to claim 20, wherein switching on the switch device comprises sending a switching command signal from the energy storage system to the switch module.

28. The method according to claim 27, comprising sending the input instruction signal when the energy storage system determines that the power grid system is synchronized with the main power grid.

29. The method according to claim 20, wherein the switch module comprises an intelligent electronic device, the intelligent electronic device is coupled to the switch device, and switching on the switch device comprises the energy storage system sending a switching command signal to the intelligent electronic device and using the intelligent electronic device to start the switching device switching operation.

30. The method of claim 17, wherein tripping the switching device comprises opening contacts of the switching device.

Images