A plant interconnection system and a method for operating the same

Abstract

The embodiment of the present disclosure provides a kind of plant electricity interconnection system and its operating method, comprising: generator set, energy storage device and plant electricity circuit;The generator set, the energy storage device, the plant electricity circuit and power grid are connected respectively;The generator set is used to provide electrical energy for energy storage device, plant electricity circuit and power grid;The energy storage device is used to convert the electrical energy provided by generator set into heat energy storage, and convert heat energy into electrical energy according to the need of power grid and output to power grid;The plant electricity circuit is used to receive the electrical energy delivered by the generator set to maintain the operation of equipment in power plant, and according to the power supply condition of the generator set, switch to power supply by the power grid or the energy storage device.Plant electricity interconnection system can ensure that in the case of generator set shutdown, plant equipment can still maintain operation;And the energy storage device can not occupy the original high-voltage plant transformer capacity, to facilitate flexible modification to existing power plant.

Description

Technical Field

[0001] This disclosure relates to the field of power system energy storage, and in particular to a plant power interconnection system and its operation method. Background Technology

[0002] The increasing number of new energy-based power equipment in current power systems places higher demands on the deep peak-shaving capabilities of traditional coal-fired power units. Molten salt energy storage technology, with its advantages of large storage capacity, long storage duration, good economics, and long service life, can effectively improve the thermoelectric decoupling capability of coal-fired power units, becoming an important technical route for the transformation of traditional coal-fired power units. However, to meet greater peak-shaving demands, the scale of supporting molten salt energy storage systems is expanding, and the power load of their core electric heating systems is also increasing. Existing traditional plant auxiliary power wiring methods in coal-fired power plants have significant limitations when connecting large-capacity molten salt energy storage systems. On the one hand, existing molten salt energy storage equipment is usually powered by high-voltage plant auxiliary transformers, but the capacity of these transformers is usually only sufficient for conventional auxiliary equipment, with limited margin. Directly connecting large-capacity molten salt energy storage loads is easily limited by the capacity bottleneck of the high-voltage plant transformers, leading to transformer overload. Furthermore, replacing the transformers with large-capacity ones requires a redesign of the power plant's spatial layout and wiring, which may affect the normal operation of the power plant, making implementation difficult. On the other hand, if a high-power load is connected using the conventional plant voltage level, it will result in an excessively large operating current in the power plant's power distribution system, placing higher demands on the current-carrying capacity of existing switchgear and cables, and significantly increasing the system's cost.

[0003] Therefore, there is an urgent need for a plant power connection scheme and operation mode that can overcome capacity limitations, reduce distribution current and cost. Summary of the Invention

[0004] This disclosure provides a power plant interconnection system and its operation method to solve the problem that existing power plants have difficulty connecting to large-capacity energy storage systems.

[0005] In view of the above problems, in the first aspect, the present disclosure provides a plant power interconnection system, including: a generator set, an energy storage device and a plant power circuit; The generator set, the energy storage device, the plant power circuit, and the power grid are respectively connected; the generator set is used to provide power to the energy storage device, the plant power circuit, and the power grid. The energy storage device is used to convert the electrical energy provided by the generator set into thermal energy for storage, and to convert the thermal energy into electrical energy for output to the grid as needed. The plant power circuit is used to receive the electrical energy transmitted by the generator set to maintain the operation of the equipment in the power plant, and to switch to power supply from the power grid or the energy storage device according to the power supply status of the generator set.

[0006] In conjunction with the first aspect, in one possible implementation, the generator set includes at least one generator; The generator is connected to the energy storage device via a closed busbar, and a machine-end load switch is installed between the closed busbar and the energy storage device; the machine-end load switch is used to switch the on / off state of the closed busbar between the generator and the energy storage device. A main transformer is installed between the generator and the power grid; the main transformer is used to step up the electrical energy output by the generator set and transmit it to the power grid.

[0007] In conjunction with the first aspect, in one possible implementation, the energy storage device includes a plurality of energy storage units and an energy storage bus; the plurality of energy storage units are connected to the energy storage bus in parallel. The energy storage unit is used to convert the received electrical energy into heat energy for storage, or to output the heat energy to the generator set; The energy storage bus is connected to the generator via an energy storage transformer; the low-voltage side of the energy storage transformer is connected to the generator, and the high-voltage side of the energy storage transformer is connected to the energy storage bus. An incoming circuit breaker is installed between the high-voltage side of the energy storage transformer and the energy storage busbar; the incoming circuit breaker is used to switch the circuit between the energy storage transformer and the energy storage busbar.

[0008] The energy storage bus is connected to the plant power circuit via an interconnecting transformer; the high-voltage side of the interconnecting transformer is connected to the energy storage bus, and the low-voltage side of the interconnecting transformer is connected to the plant power circuit; the interconnecting transformer is used to step down the voltage of the electrical energy transmitted on the energy storage bus before transmitting it to the plant power circuit.

[0009] In conjunction with the first aspect, in one possible implementation, the plant power circuit includes a plant power interconnection bus and a plurality of high-voltage plant power buses; each high-voltage plant power bus corresponds to one of the generators in the generator set; The high-voltage plant service busbar is connected to the power grid, the plant service interconnection busbar, and the corresponding generator respectively; the high-voltage plant service busbar is used to transmit the electrical energy transmitted from the power grid, the generator, or the plant service interconnection busbar to the various electrical equipment of the generator. The plant power interconnection busbar is connected to the energy storage equipment and each high-voltage plant power busbar respectively; the plant power interconnection busbar is used to transmit electrical energy between different high-voltage plant power busbars and energy storage equipment.

[0010] In conjunction with the first aspect, in one possible implementation, the high-voltage plant busbar is connected to the generator via a high-voltage plant transformer; the high-voltage side of the high-voltage plant transformer is connected to the generator, and the low-voltage side of the high-voltage plant transformer is connected to the high-voltage plant busbar. The high-voltage plant service transformer is used to step down the voltage of the electrical energy output by the generator and transmit it to the high-voltage plant service bus. A working circuit breaker is installed between the low-voltage side of the high-voltage plant service transformer and the high-voltage plant service busbar; the working circuit breaker is used to switch the circuit between the high-voltage plant service transformer and the high-voltage plant service busbar.

[0011] In conjunction with the first aspect, in one possible implementation, the high-voltage plant busbar is connected to the power grid via a standby transformer; the high-voltage side of the standby transformer is connected to the power grid, and the low-voltage side of the standby transformer is connected to the high-voltage plant busbar. The backup transformer is used to step down the voltage of the power grid and transmit it to the high-voltage plant busbar. A backup circuit breaker is installed between the high-voltage plant busbar and the backup transformer; the backup circuit breaker is used to switch the circuit between the high-voltage plant busbar and the backup transformer. In conjunction with the first aspect, in one possible implementation, an interconnection circuit breaker is provided between the plant power interconnection bus and any high-voltage plant power bus; the interconnection circuit breaker is used to switch the on / off state of the circuit between the plant power interconnection bus and the high-voltage plant power bus.

[0012] In conjunction with the first aspect, in one possible implementation, the energy storage bus is divided into multiple energy storage bus segments according to the number of generators in the generator set; each energy storage bus segment is connected to the corresponding generator and connected to a preset number of energy storage units; Each energy storage bus section is equipped with a bus tie circuit breaker; the bus tie circuit breaker is used to switch the on and off of the circuit between the energy storage bus sections.

[0013] A second aspect of this disclosure provides a method for operating a plant power interconnection system, including: Energy storage devices are put into peak-shaving operations according to the peak-shaving needs of the power grid. Based on the power supply status of the generator set, the state of the circuit breaker in the plant power interconnection system is switched, so that the energy storage device changes its peak-shaving operation strategy and changes the circuit drawer of the plant power circuit; wherein, the plant power interconnection system is the plant power interconnection system described in any one of the first aspects.

[0014] In conjunction with the second aspect, in one possible implementation, the step of deploying energy storage devices for peak shaving operations according to the grid's peak shaving needs includes: When the power grid has peak-shaving demand, the load switch and incoming circuit breaker at the generator end are closed, the bus tie circuit breaker is opened, the high-voltage side of the interconnecting transformer is adjusted to the open state, the interconnecting circuit breaker is opened, the working circuit breaker is closed, and the standby circuit breaker is opened, so that the energy storage unit connected to each energy storage bus section only interacts with the corresponding generator and the power grid, and cooperates with the corresponding generator to carry out peak-shaving operations.

[0015] In conjunction with the second aspect, in one possible implementation, the step of switching the state of the circuit breaker in the plant power interconnection system according to the power supply status of the generator set, so as to change the peak-shaving operation strategy of the energy storage device, includes: In the event that any generator in the generator set is shut down, disconnect the incoming circuit breaker and the load switch between the generator and the corresponding energy storage bus section, close the bus tie circuit breaker, turn on the interconnecting transformer, close the interconnecting circuit breaker corresponding to the generator, disconnect the working circuit breaker corresponding to the generator, disconnect the standby circuit breaker, and put the energy storage unit corresponding to the shut-down generator set into the peak shaving operation of other generator sets. When all generators in the generator set are shut down, disconnect the load switch and incoming circuit breaker at the generator end, close the bus tie circuit breaker, turn on the interconnecting transformer, disconnect the interconnecting circuit breaker and the working circuit breaker, close the standby circuit breaker, and input the power supplied by the grid into the energy storage device. The beneficial effects of the embodiments disclosed herein include: This disclosure provides a plant power interconnection system and its operation method, comprising: a generator set, an energy storage device, and a plant power circuit; the generator set, the energy storage device, the plant power circuit, and the power grid are respectively connected; the generator set is used to provide electrical energy to the energy storage device, the plant power circuit, and the power grid; the energy storage device is used to convert the electrical energy provided by the generator set into thermal energy for storage, and to convert the thermal energy into electrical energy for output to the power grid according to the needs of the power grid; the plant power circuit is used to receive the electrical energy transmitted by the generator set to maintain the operation of the equipment in the power plant, and to switch to power supply from the power grid or the energy storage device according to the power supply status of the generator set. The plant power interconnection system disclosed herein can switch power supply between generator sets, the power grid, and energy storage devices, ensuring that plant equipment can maintain continuous and stable operation in the event of generator set shutdown or failure. Furthermore, it can physically parallel and separate energy storage loads from plant power loads, so that energy storage devices do not occupy the capacity of the original high-voltage plant transformers and there is no need to upgrade the original transformers. As a result, energy storage devices can be connected without affecting the normal operation of existing units, which facilitates flexible transformation of existing power plants. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a plant power interconnection system provided in an embodiment of the present disclosure; Figure 2 This is a flowchart illustrating an operation method for a plant power interconnection system provided in an embodiment of this disclosure. Detailed Implementation

[0017] This disclosure provides a plant power interconnection system and its operation method. Preferred embodiments of this disclosure are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit this disclosure. Furthermore, the embodiments and features described in this application can be combined with each other unless otherwise specified.

[0018] This disclosure provides a plant power interconnection system, such as... Figure 1 As shown, it includes: generator set 1, energy storage device 2, and plant power circuit 3; The generator set 1, the energy storage device 2, the plant power circuit 3, and the power grid are respectively connected; the generator set 1 is used to provide power to the energy storage device 2, the plant power circuit 3, and the power grid. The energy storage device 2 is used to convert the electrical energy provided by the generator set 1 into thermal energy for storage, and to convert the thermal energy into electrical energy and output it to the grid according to the grid's needs; The plant power circuit 3 is used to receive the electrical energy transmitted by the generator set 1 to maintain the operation of the equipment in the power plant, and to switch to power supply from the power grid or the energy storage device 2 according to the power supply status of the generator set 1.

[0019] In this embodiment, generator set 1 is mainly the main generator system of a thermal power plant, which outputs electrical energy through the isolated phase closed busbar led out from the generator terminal. As the core power source of the system, the electrical energy generated by generator set 1 is divided into three paths: one path is stepped up by the main transformer and sent to the power grid; another path is stepped down by the high-voltage plant service transformer and sent to the plant service circuit 3; and the third path is sent to the energy storage device 2 for peak shaving and energy storage.

[0020] The following is combined Figure 1 This disclosure provides an explanation of the plant power interconnection system, such as... Figure 1 The example shown uses generator set 1, which includes two generators. Depending on actual needs, the plant power interconnection system provided in this disclosure can be applied to power plants with varying numbers of generators.

[0021] The energy storage device 2 here can be a molten salt thermal energy storage system. This device can be connected to the isolated phase busbar at the generator terminal of generator set 1 via a dedicated molten salt energy storage transformer. The molten salt energy storage transformer is configured as a step-up transformer, responsible for increasing the generator's output voltage, thereby driving the molten salt electric heating system with a smaller operating current. During the energy storage phase, the device uses the electrical energy of generator set 1 to heat the low-temperature molten salt into high-temperature molten salt for storage. During the energy release phase, the thermal energy of the stored high-temperature molten salt is used to generate steam, which then drives turbine generator set 1 to generate electricity and output it to the grid. It should be noted that, depending on the actual conditions of the power plant, the energy storage device here can also be replaced with chemical energy storage devices such as supercapacitors or lithium battery packs, and the circuit configuration can be adjusted accordingly.

[0022] The plant auxiliary power circuit 3 is the power supply and distribution network that ensures the normal operation of various equipment within the power plant (e.g., auxiliary machines and accessories). Its power source can be the high-voltage plant auxiliary transformer at the generator terminal. Under normal operating conditions of generator set 1, the plant auxiliary power circuit 3 directly receives the electrical energy transmitted by generator set 1 to maintain its own use. When generator set 1 is in a state of shutdown, maintenance, or failure and unable to supply power, the plant auxiliary power circuit 3 will switch to power supply from the grid or from the energy storage device 2 through a switching operation, thereby ensuring continuous operation.

[0023] The architecture provided in this disclosure enables large-capacity energy storage loads and conventional plant power loads to be physically paralleled and split, without occupying transformer capacity; and existing power plants can be retrofitted based on this architecture to connect energy storage devices without affecting the operation of existing units.

[0024] In yet another embodiment provided in this disclosure, such as Figure 1 As shown, the generator set 1 includes at least one generator; The generator is connected to the energy storage device 2 via a closed busbar, and a machine-end load switch 11 is installed between the closed busbar and the energy storage device 2; the machine-end load switch 11 is used to switch the on / off state of the closed busbar between the generator and the energy storage device 2. A main transformer 12 is installed between the generator and the power grid; the main transformer 12 is used to step up the electrical energy output by the generator set 1 and transmit it to the power grid.

[0025] In this embodiment of the disclosure, the generator set 1 may include one or more generators operating in parallel. Each generator is equipped with a corresponding main transformer 12, which can step up the lower voltage (e.g., 10kV to 20kV range) output from the generator set 1 to a voltage level suitable for long-distance transmission (e.g., 200kV and 500kV).

[0026] Meanwhile, each generator is connected to the energy storage device 2 via a generator-end load switch 11 corresponding to that generator set 1. This switch is connected in series in the connection line between the generator and the energy storage device 2, and its core function is to achieve electrical isolation and on / off control. In actual operation scenarios, when energy storage is required (for example, when the power grid is in a low-voltage period), the generator-end load switch 11 is closed, and the electrical energy generated by the generator is diverted into the energy storage device 2; when the energy storage device 2 reaches its maximum storage capacity, malfunctions, is under maintenance, or the generator needs to supply full power to the grid, the switch can perform an open operation, completely disconnecting the branch of the energy storage device 2 corresponding to that generator.

[0027] In yet another embodiment provided in this disclosure, such as Figure 1 As shown, the energy storage device 2 includes multiple energy storage units 21 and an energy storage bus 22; the multiple energy storage units 21 are connected to the energy storage bus 22 in parallel. The energy storage unit 21 is used to convert the received electrical energy into heat energy for storage, or to output the heat energy to the generator set 1; The energy storage bus 22 is connected to the generator through the energy storage transformer 23; the low-voltage side of the energy storage transformer 23 is connected to the generator, and the high-voltage side of the energy storage transformer 23 is connected to the energy storage bus 22. An incoming circuit breaker 24 is provided between the high-voltage side of the energy storage transformer 23 and the energy storage bus 22; the incoming circuit breaker 24 is used to switch the circuit between the energy storage transformer 23 and the energy storage bus 22. The energy storage bus 22 is connected to the plant power circuit 3 via the interconnecting transformer 25; the high-voltage side of the interconnecting transformer 25 is connected to the energy storage bus 22, and the low-voltage side of the interconnecting transformer 25 is connected to the plant power circuit 3; the interconnecting transformer 25 is used to step down the voltage of the electrical energy transmitted on the energy storage bus 22 and then transmit it to the plant power circuit 3.

[0028] In this embodiment, the energy storage device 2 can be constructed as a cluster system comprising multiple energy storage units 21. These energy storage units 21 are connected in parallel to a unified energy storage bus 22. Energy storage units 21 that need to be put into peak-shaving operation can be selected according to actual peak-shaving requirements. Even if one unit fails, it will not affect the normal operation of other units on the energy storage bus 22. Specifically, the energy storage device 2 of this disclosure can be a molten salt energy storage device 2, where each energy storage unit 21 can be a molten salt load, and each molten salt load can include a molten salt heater, insulation equipment, and heat exchange equipment. The molten salt heater can use the electrical energy transmitted on the molten salt bus to heat the low-temperature molten salt stored in the molten salt load to a high-temperature storage temperature; the insulation equipment can maintain the heat energy of the high-temperature molten salt from being lost; and the heat exchange equipment can be a device that outputs the heat energy stored in the molten salt load to the generator for auxiliary power generation.

[0029] To match the voltage level difference between the generator output voltage and the energy storage system, an energy storage transformer 23 is installed between the generator and the energy storage system. The number of energy storage transformers 23 is determined according to the number of generators in generator set 1, and each generator is connected to a corresponding energy storage transformer 23. This energy storage transformer 23 can adopt a step-up structure, with its low-voltage side connected to the generator output terminal (e.g., 20kV level) and its high-voltage side connected to the energy storage bus 22 (e.g., 35kV level). An incoming circuit breaker 24 can be installed between the high-voltage side of the energy storage transformer 23 and the energy storage bus 22 to switch the circuit between the energy storage transformer 23 and the energy storage bus 22.

[0030] Furthermore, in this embodiment, an energy exchange channel between the energy storage system and the plant power circuit 3 is established through the interconnection transformer 25. When a generator in generator set 1 stops, the auxiliary equipment of that generator can draw power from other generators in generator set 1 through the interconnection transformer 25 and the energy storage bus 22 to maintain the operation of the auxiliary equipment of that generator and ensure the safe operation of generator set 1.

[0031] In yet another embodiment provided in this disclosure, such as Figure 1 As shown, the plant power circuit 3 includes a plant power interconnection bus 31 and multiple high-voltage plant power buses 32; each high-voltage plant power bus 32 corresponds to one of the generators in the generator set 1. The high-voltage plant busbar 32 is connected to the power grid, the plant power interconnection busbar 31, and the corresponding generator respectively; the high-voltage plant busbar 32 is used to transmit the electrical energy transmitted from the power grid, the generator, or the plant power interconnection busbar 31 to the various electrical equipment of the generator. The plant power interconnection bus 31 is connected to the energy storage device 2 and each high-voltage plant power bus 32 respectively; the plant power interconnection bus 31 is used to transmit electrical energy between different high-voltage plant power buses 32 and energy storage devices 2.

[0032] In this embodiment of the disclosure, multiple power supply sources are provided for the plant power system by setting up the plant power interconnection bus 31.

[0033] The high-voltage station service bus 32 serves as the power supply line for each generator's auxiliary equipment, providing multiple power input paths. Generator auxiliary equipment refers to a series of supporting devices and systems that must be configured to ensure the safe, stable, and continuous operation of the generator itself. These auxiliary equipment must be kept operational during generator operation, and must be started first before the generator starts. Specifically, the high-voltage station service bus 32 can receive electrical energy output from its own generator, as well as reverse-feeding energy from the external power grid, and can also receive electrical energy from other power sources via the station service interconnection bus 31.

[0034] The connection via the plant auxiliary power interconnection bus 31 establishes an electrical link between the energy storage device 2 and the plant auxiliary power systems of all generators in the plant, forming a power transmission channel between different high-voltage plant auxiliary buses 32. Under specific operating conditions, such as when a generator is out of service, the high-voltage plant auxiliary bus 32 of that generator can obtain power from the high-voltage plant auxiliary buses 32 of other normally operating generators through the plant auxiliary power interconnection bus 31. This structure provides power redundancy for the plant auxiliary power system, ensuring the continuity of power supply to the auxiliary equipment of generator set 1.

[0035] In yet another embodiment provided in this disclosure, such as Figure 1 As shown, the high-voltage plant busbar 32 is connected to the generator via a high-voltage plant transformer 13; the high-voltage side of the high-voltage plant transformer 13 is connected to the generator, and the low-voltage side of the high-voltage plant transformer 13 is connected to the high-voltage plant busbar 32. The high-voltage plant transformer 13 is used to step down the voltage of the electrical energy output by the generator and transmit it to the high-voltage plant bus 32. A working circuit breaker 14 is provided between the low-voltage side of the high-voltage plant transformer 13 and the high-voltage plant bus 32; the working circuit breaker 14 is used to switch the circuit between the high-voltage plant transformer 13 and the high-voltage plant bus 32.

[0036] In this embodiment, the generator is supplied with power to its own high-voltage station service bus via a high-voltage station service transformer 13. The high-voltage station service transformer 13 is used to perform voltage conversion between the generator output voltage level and the station service voltage level. The electrical energy generated by the generator is input via the high-voltage side of the high-voltage station service transformer 13, stepped down on the low-voltage side to a voltage level suitable for the operation of auxiliary generators in the plant, and then transmitted to the high-voltage station service bus 32.

[0037] The working circuit breaker 14 on the low-voltage side of the high-voltage station service transformer 13 is the control switch for the branch of the high-voltage station service bus 32. During normal operation of the generator, the working circuit breaker 14 is in the closed state, maintaining the self-supply of station service power. When the generator fails and shuts down, the working circuit breaker 14 opens, thereby electrically isolating the high-voltage station service transformer 13 from the high-voltage station service bus 32 and preventing backfeeding to the transformer.

[0038] In yet another embodiment provided in this disclosure, such as Figure 1 As shown, the high-voltage plant busbar 32 is connected to the power grid via a standby transformer 15; the high-voltage side of the standby transformer 15 is connected to the power grid, and the low-voltage side of the standby transformer 15 is connected to the high-voltage plant busbar 32. The backup transformer 15 is used to step down the voltage of the power grid and transmit it to the high-voltage plant busbar 32. A backup circuit breaker 16 is provided between the high-voltage plant busbar 32 and the backup transformer 15; the backup circuit breaker 16 is used to switch the circuit between the high-voltage plant busbar 32 and the backup transformer 15.

[0039] In this embodiment, the backup transformer 15 is located between the external power grid and the high-voltage plant busbar 32 within the plant, primarily performing voltage transformation and power transmission functions. Power supplied by the external power grid is transmitted to the high-voltage side of the backup transformer 15, where it is stepped down and converted to a voltage level suitable for the operation of auxiliary equipment within the plant, and then output from the low-voltage side.

[0040] The standby circuit breaker 16, serving as the on / off control device for this branch, is located at the connection point between the low-voltage side of the standby transformer 15 and the high-voltage plant service bus 32. The opening state of this circuit breaker determines whether the power grid supplies power to the high-voltage plant service bus 32. In the event of a fault in generator set 1, the standby circuit breaker 16 is in the closed state, introducing grid power as a substitute to ensure that critical auxiliary equipment within the plant does not lose power.

[0041] In yet another embodiment provided in this disclosure, such as Figure 1 As shown, an interconnection circuit breaker 33 is provided between the plant power interconnection bus 31 and any high-voltage plant power bus 32; the interconnection circuit breaker 33 is used to switch the on / off state of the circuit between the plant power interconnection bus 31 and the high-voltage plant power bus 32.

[0042] In this embodiment, the interconnecting circuit breaker 33 can serve as an actuator for switching the circuit on and off. By controlling the electrical connection state between the high-voltage station service bus 32 on the generator side and the station service interconnecting bus 31, the high-voltage station service bus 32 is connected to the station service interconnecting bus 31, establishing a power transmission channel. When the generator is off, by closing the interconnecting circuit breaker 33, power can be obtained through the station service interconnecting bus 31, and the power supply of the auxiliary equipment of the generator on this side can be maintained using the power of other generators.

[0043] By disconnecting the interconnecting circuit breaker 33, the high-voltage plant service bus 32 is physically isolated from the plant service interconnecting bus 31. When the generator needs to operate independently, disconnecting the interconnecting circuit breaker 33 can disconnect the high-voltage plant service system of the unit from the interconnection system, ensuring the electrical safety and independent operation of the generator and its auxiliary equipment.

[0044] In yet another embodiment provided in this disclosure, such as Figure 1 As shown, the energy storage bus 22 is divided into multiple energy storage bus segments according to the number of generators in the generator set 1; each energy storage bus segment is connected to the corresponding generator and connected to a preset number of energy storage units 21; Each energy storage bus section is equipped with a bus tie circuit breaker 26; the bus tie circuit breaker 26 is used to switch the on and off of the circuit between the energy storage bus sections.

[0045] In this embodiment of the disclosure, depending on the number and configuration of the generators in the generator set 1, the energy storage bus 22 of the entire plant is not a single continuous conductor, but is electrically segmented to form multiple energy storage bus segments that correspond one-to-one with the generators.

[0046] Each energy storage bus segment constitutes an independent combiner node, which gathers several energy storage units 21 and can supply power to these energy storage units 21. This correspondence enables each energy storage bus segment to perform peak shaving for the generators connected to it, facilitating adjustments for power fluctuations of individual generators.

[0047] Electrical connections between the various energy storage bus sections can be achieved through bus tie circuit breakers 26. When the bus tie circuit breaker 26 is open, the various energy storage bus sections are isolated from each other, and the energy storage units 21 connected to each other only perform peak-shaving operations on their corresponding generators, without interfering with each other, and their operating range is limited to a single bus section.

[0048] When the bus tie circuit breaker 26 is closed, adjacent energy storage bus sections are electrically connected. At this time, the energy storage resources of the power plant can be shared. For example, when the energy storage resources corresponding to a certain generator are insufficient to respond to peak shaving commands in a timely manner, idle energy storage resources on adjacent bus sections can be called for peak shaving by closing the bus tie circuit breaker 26.

[0049] This disclosure also provides a method for operating a plant power interconnection system, such as... Figure 2 As shown, it can be implemented as follows: S101. Based on the peak-shaving demand of the power grid, put the energy storage device 2 into peak-shaving operation; S102. Based on the power supply status of generator set 1, switch the state of the circuit breaker of the plant power interconnection system, so that the energy storage device 2 changes the peak shaving operation strategy and changes the circuit draw of the plant power circuit 3; wherein, the plant power interconnection system is the plant power interconnection system described in any of the above embodiments.

[0050] In this embodiment of the disclosure, when the grid load is at a low point or when deep peak shaving by generating units is required, the energy storage units 21 connected to the energy storage bus 22 are activated. By controlling these energy storage units 21 to absorb excess electrical energy or output stored energy, they participate in the grid's peak shaving operation.

[0051] While energy storage device 2 participates in peak shaving, the operating conditions of the generator in generator set 1 (such as normal power generation, shutdown, or fault) are determined by monitoring the power supply status of generator set 1. Based on these operating conditions, the on / off status of the circuit breaker in the plant power interconnection system is adjusted, thereby changing the operating strategy of energy storage device 2 and the power supply path of plant power.

[0052] In another embodiment provided in this disclosure, step S101 above, "putting the energy storage device 2 into peak-shaving operation according to the peak-shaving demand of the power grid," can be implemented as follows: When the power grid has peak shaving demand, the load switch 11 at the generator end and the incoming circuit breaker 24 are closed, the bus tie circuit breaker 26 is disconnected, the high-voltage side of the interconnecting transformer 25 is adjusted to the disconnected state, the interconnecting circuit breaker 33 is disconnected, the working circuit breaker 14 is closed, and the standby circuit breaker 16 is disconnected, so that the energy storage unit 21 connected to each energy storage bus section only interacts with the corresponding generator and the power grid, and cooperates with the corresponding generator to carry out peak shaving operations.

[0053] In this embodiment of the disclosure, when there is a demand for peak shaving, by disconnecting the bus tie circuit breaker 26 and the interconnection circuit breaker 33, the plant power interconnection network is electrically decoupled into several relatively independent power generation and energy storage subsystems, thus avoiding power circulation or mutual interference between different generators.

[0054] Specifically, if the power grid requires the generator to increase its load, the thermal power generator is limited by the slow ramp-up rate of the boiler thermal inertia. The energy storage device 2 paired with it releases energy (taking the molten salt energy storage device as an example, the high temperature molten salt generates steam through the heat exchanger and outputs it to the generator to assist the generator in operation) to compensate for the power gap and enable the generator's grid-connected power to meet the dispatch requirements. Conversely, if the power grid requires the generator to reduce its load, the energy storage device 2 paired with the generator absorbs energy (taking a molten salt energy storage device as an example, the energy storage device 2 absorbs electrical energy and heats and stores the low-temperature molten salt through a heater), thereby improving the regulation rate of the generator set 1.

[0055] With the working circuit breaker 14 in the closed state, the generator continuously supplies power to the high-voltage plant bus 32 of the machine through the high-voltage plant service transformer 13 while transmitting power to the grid, thus maintaining the normal operation of the auxiliary machines in the plant.

[0056] In another embodiment provided in this disclosure, the above step S102, "switching the state of the circuit breaker in the plant power interconnection system according to the power supply status of generator set 1, so that the energy storage device 2 changes its peak-shaving operation strategy," can be implemented as follows: Step 1: When any generator in generator set 1 is shut down, disconnect the incoming circuit breaker 24 and the load switch 11 between the generator and the corresponding energy storage bus section, close the bus tie circuit breaker 26, turn on the interconnection transformer 25, close the interconnection circuit breaker 33 corresponding to the generator, disconnect the working circuit breaker 14 corresponding to the generator, disconnect the standby circuit breaker 16, so that the energy storage unit 21 corresponding to the shut-down generator set 1 can be put into peak shaving operation of other generator sets 1. Step 2: With all generators in generator set 1 shut down, disconnect the load switch 11 and incoming circuit breaker 24 at the generator end, close the bus tie circuit breaker 26, turn on the interconnecting transformer 25, disconnect the interconnecting circuit breaker 33 and working circuit breaker 14, close the standby circuit breaker 16, and input the power supplied by the grid into the energy storage device 2. In this embodiment, when some generators in a power plant stop operating, an interconnection path is established by operating a circuit breaker. The energy storage unit 21 corresponding to the stopped generator is connected to other energy storage bus sections by closing the bus tie circuit breaker 26. This allows excess electrical energy to be transferred to these energy storage units 21, where it is converted into heat energy for storage. Furthermore, by opening the interconnection circuit breaker 33 corresponding to the stopped generator, the high-voltage station service bus 32 of that generator draws power from the energy storage bus 22 via the station service interconnection bus 31 and the interconnection transformer 25 to maintain the operation of the generator's auxiliary equipment.

[0057] Furthermore, in the event that all generators in the plant are shut down, the system switches to grid power supply mode by closing the standby circuit breaker 16. At this time, electrical energy from the grid can be introduced into the energy storage unit 21 and the high-voltage plant service bus 32 of each generator. The grid power can then be used to insulate the molten salt in the energy storage unit 21, preventing it from solidifying due to temperature drops in the pipelines or storage tanks, ensuring the equipment is in a hot standby state. Simultaneously, grid power is transmitted to each high-voltage plant service bus 32 via the plant service interconnection bus 31 to power the auxiliary equipment of each generator. If the power plant needs to resume operation, the stored thermal energy can be used to generate steam, thereby assisting the generators in achieving rapid startup.

[0058] Through the above description of the embodiments, those skilled in the art can clearly understand that the embodiments of this disclosure can be implemented in hardware or by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solutions of the embodiments of this disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, mobile hard drive, etc.) and includes several instructions to cause a computer device (such as a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments of this disclosure.

[0059] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of a preferred embodiment, and the modules or processes in the drawings are not necessarily essential for implementing this disclosure.

[0060] Those skilled in the art will understand that the modules in the apparatus of the embodiments can be distributed in the apparatus of the embodiments as described in the embodiments, or they can be located in one or more devices different from this embodiment with corresponding changes. The modules of the above embodiments can be combined into one module, or they can be further divided into multiple sub-modules.

[0061] The sequence numbers of the embodiments disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0062] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

1. A plant power interconnection system, characterized in that, include: Generator sets, energy storage devices, and plant power circuits; The generator set, the energy storage device, the plant power circuit, and the power grid are respectively connected; the generator set is used to provide power to the energy storage device, the plant power circuit, and the power grid. The energy storage device is used to convert the electrical energy provided by the generator set into thermal energy for storage, and to convert the thermal energy into electrical energy for output to the grid as needed. The plant power circuit is used to receive the electrical energy transmitted by the generator set to maintain the operation of the equipment in the power plant, and to switch to power supply from the power grid or the energy storage device according to the power supply status of the generator set.

2. The system as described in claim 1, characterized in that, The generator set includes at least one generator; The generator is connected to the energy storage device via a closed busbar, and a machine-end load switch is installed between the closed busbar and the energy storage device; the machine-end load switch is used to switch the on / off state of the closed busbar between the generator and the energy storage device. A main transformer is installed between the generator and the power grid; the main transformer is used to step up the voltage of the electrical energy output by the generator set and transmit it to the power grid.

3. The system as described in claim 1, characterized in that, The energy storage device includes multiple energy storage units and an energy storage bus; the multiple energy storage units are connected to the energy storage bus in parallel. The energy storage unit is used to convert the received electrical energy into heat energy for storage, or to output the heat energy to the generator set; The energy storage bus is connected to the generator via an energy storage transformer; the low-voltage side of the energy storage transformer is connected to the generator, and the high-voltage side of the energy storage transformer is connected to the energy storage bus. An incoming circuit breaker is installed between the high-voltage side of the energy storage transformer and the energy storage busbar; the incoming circuit breaker is used to switch the circuit between the energy storage transformer and the energy storage busbar. The energy storage bus is connected to the plant power circuit via an interconnecting transformer; the high-voltage side of the interconnecting transformer is connected to the energy storage bus, and the low-voltage side of the interconnecting transformer is connected to the plant power circuit; the interconnecting transformer is used to step down the voltage of the electrical energy transmitted on the energy storage bus before transmitting it to the plant power circuit.

4. The system as described in claim 1, characterized in that, The plant power circuit includes a plant power interconnection busbar and multiple high-voltage plant power busbars; each high-voltage plant power busbar corresponds to one generator in the generator set. The high-voltage plant service busbar is connected to the power grid, the plant service interconnection busbar, and the corresponding generator respectively; the high-voltage plant service busbar is used to transmit the electrical energy transmitted from the power grid, the generator, or the plant service interconnection busbar to the various electrical equipment of the generator. The plant power interconnection busbar is connected to the energy storage equipment and each high-voltage plant power busbar respectively; the plant power interconnection busbar is used to transmit electrical energy between different high-voltage plant power busbars and energy storage equipment.

5. The system as described in claim 4, characterized in that, The high-voltage plant busbar is connected to the generator via a high-voltage plant transformer; the high-voltage side of the high-voltage plant transformer is connected to the generator, and the low-voltage side of the high-voltage plant transformer is connected to the high-voltage plant busbar. The high-voltage plant service transformer is used to step down the voltage of the electrical energy output by the generator and transmit it to the high-voltage plant service bus. A working circuit breaker is installed between the low-voltage side of the high-voltage plant service transformer and the high-voltage plant service busbar; the working circuit breaker is used to switch the circuit between the high-voltage plant service transformer and the high-voltage plant service busbar.

6. The system as described in claim 4, characterized in that, The high-voltage plant busbar is connected to the power grid via a standby transformer; the high-voltage side of the standby transformer is connected to the power grid, and the low-voltage side of the standby transformer is connected to the high-voltage plant busbar. The backup transformer is used to step down the voltage of the power grid and transmit it to the high-voltage plant busbar. A backup circuit breaker is installed between the high-voltage plant busbar and the backup transformer; the backup circuit breaker is used to switch the circuit between the high-voltage plant busbar and the backup transformer.

7. The system as described in claim 4, characterized in that, An interconnection circuit breaker is installed between the plant power interconnection busbar and any high-voltage plant power busbar; the interconnection circuit breaker is used to switch the circuit between the plant power interconnection busbar and the high-voltage plant power busbar.

8. The system as described in claim 3, characterized in that, The energy storage bus is divided into multiple energy storage bus segments according to the number of generators in the generator set; each energy storage bus segment is connected to the corresponding generator and connected to a preset number of energy storage units; Each energy storage bus section is equipped with a bus tie circuit breaker; the bus tie circuit breaker is used to switch the on and off of the circuit between the energy storage bus sections.

9. A method for operating a plant power interconnection system, characterized in that, include: Based on the peak-shaving needs of the power grid, energy storage devices are put into peak-shaving operations; Based on the power supply status of the generator set, the state of the circuit breaker in the plant power interconnection system is switched to change the peak-shaving operation strategy of the energy storage device and change the circuit drawer of the plant power circuit; wherein, the plant power interconnection system is the plant power interconnection system as described in any one of claims 1-8.

10. The method as described in claim 9, characterized in that, The process of deploying energy storage devices for peak shaving operations based on the grid's peak shaving needs includes: When the power grid has peak-shaving demand, the load switch and incoming circuit breaker at the generator end are closed, the bus tie circuit breaker is opened, the high-voltage side of the interconnecting transformer is adjusted to the open state, the interconnecting circuit breaker is opened, the working circuit breaker is closed, and the standby circuit breaker is opened, so that the energy storage unit connected to each energy storage bus section only interacts with the corresponding generator and the power grid, and cooperates with the corresponding generator to carry out peak-shaving operations.

11. The method as described in claim 9, characterized in that, The method of switching the state of the circuit breaker in the plant power interconnection system according to the power supply status of the generator set, so as to change the peak-shaving operation strategy of the energy storage equipment, includes: In the event that any generator in the generator set is shut down, disconnect the incoming circuit breaker and the load switch between the generator and the corresponding energy storage bus section, close the bus tie circuit breaker, turn on the interconnecting transformer, close the interconnecting circuit breaker corresponding to the generator, disconnect the working circuit breaker corresponding to the generator, disconnect the standby circuit breaker, and put the energy storage unit corresponding to the shut-down generator set into the peak shaving operation of other generator sets. When all generators in the generator set are shut down, disconnect the load switch and incoming circuit breaker at the generator end, close the bus tie circuit breaker, turn on the interconnecting transformer, disconnect the interconnecting circuit breaker and the working circuit breaker, close the standby circuit breaker, and input the power supplied by the grid into the energy storage device.

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