A high-reliability emergency power supply system for coal-fired power plants based on all-vanadium redox flow batteries

Abstract

The utility model relates to the technical field of coal-fired power plant power system emergency power supply, and particularly relates to a coal-fired power plant high reliability emergency power supply system based on all-vanadium liquid flow battery, which comprises an all-vanadium liquid flow battery system, a bidirectional converter, a grid-connected circuit breaker, an intelligent microgrid controller and a safety protection device. The all-vanadium liquid flow battery system comprises an electric pile, positive and negative electrolyte storage tanks, a circulating pump and a battery management system. The direct current output end of the all-vanadium liquid flow battery system is connected to the direct current side of the bidirectional converter, and the alternating current side of the bidirectional converter is connected to the 380V power distribution section of the power plant through the grid-connected circuit breaker. The system cooperates with the auxiliary power to operate normally and assists in peak regulation. When a fault occurs, the intelligent microgrid controller triggers seamless switching to an off-grid mode within 50 milliseconds, and independently carries the key load. The utility model solves the problems of slow switching and low reliability of traditional emergency power supply, is environmentally friendly and safe, and is modular in design, which facilitates expansion and maintenance and is suitable for emergency power supply of key equipment in coal-fired power plants.

Description

TECHNICAL FIELD

[0001] The utility model coal -fired power plant emergency power supply of electric power system belongs to technical field, specifically related to a kind of coal -fired power plant high reliability emergency power supply system based on all-vanadium redox battery. BACKGROUND

[0002] In the operation of coal-fired power plant, DCS control system, circulating water pump, lubricating oil station and other key equipment have very high requirement on power supply continuity, once plant power system is interrupted, emergency power supply needs to respond quickly and stably supply power, otherwise it may cause equipment damage and even cause safety accident.

[0003] At present, coal-fired power plant generally uses diesel engine as emergency power supply, but this kind of power supply has significant limitations: first, response speed is slow, diesel engine usually needs 10~20 seconds from receiving start signal to realizing full load power supply, and it needs to be preheated in low temperature environment, which further prolongs response time, and it is difficult to meet the demand of millisecond level power supply switching of key equipment;Second, reliability is not high, diesel engine is in cold standby state for a long time, and abnormality may occur in wearing parts such as oil, filter, spark plug and piston, crankshaft, which may cause start failure and cannot guarantee emergency power supply;Third, environmental protection is poor, diesel combustion will produce pollutants such as nitrogen oxides (NOx) and particulate matter (PM), which does not meet environmental protection requirements;Fourth, there is risk of fuel storage, long-term storage of diesel oil is easy to leak, volatilize and even cause fire;Fifth, energy efficiency is low, power generation efficiency is usually only 30%~40%, and economy is poor.

[0004] In view of the above-mentioned deficiencies of traditional diesel engine emergency power supply in response speed, reliability, environmental protection, safety and economy, a high-reliability, fast-response emergency power supply system is needed to meet the emergency power supply demand of key equipment of coal-fired power plant and improve the safety and stability of power plant power system. CONTENT OF UTILITY MODEL

[0005] In view of the above-mentioned technical problems of traditional diesel engine emergency power supply, the utility model provides a kind of coal -fired power plant high reliability emergency power supply system based on all-vanadium liquid flow battery.

[0006] In order to solve the above technical problems, the technical scheme adopted by the utility model is:

[0007] A kind of coal -fired power plant high reliability emergency power supply system based on all-vanadium liquid flow battery, comprising:

[0008] Vanadium redox flow battery system, the vanadium redox flow battery system includes multiple vanadium redox flow battery stacks, positive and negative electrolyte storage tanks, electrolyte circulation pumps, and a battery management system; the positive and negative electrolyte storage tanks are connected to the vanadium redox flow battery stacks through the electrolyte circulation pumps for delivering electrolyte to the stacks; the power output terminals of the vanadium redox flow battery stacks form a DC output;

[0009] Bidirectional converter, the bidirectional converter includes a DC side interface and an AC side interface, and its DC side interface is electrically connected to the DC output terminal of the vanadium redox flow battery system for converting the DC power output by the vanadium redox flow battery into AC power;

[0010] Grid connection circuit breaker, one end of which is electrically connected to the AC side interface of the bidirectional converter, and the other end is used to be electrically connected to the 380V power distribution section of the coal-fired power plant;

[0011] Intelligent microgrid controller, which is respectively electrically connected to the battery management system, bidirectional converter and grid connection circuit breaker of the vanadium redox flow battery system for monitoring the system status and controlling power supply switching;

[0012] Safety protection device, including a leakage monitoring component connected to the electrolyte storage tank, a fire protection component supporting the vanadium redox flow battery system and the bidirectional converter, and a protective cabinet wrapping each device.

[0013] In the vanadium redox flow battery system, multiple vanadium redox flow battery stacks are connected in parallel or series. Each stack is internally provided with an ion exchange membrane and electrodes, and the electrolyte is sealed through a seal; the electrolyte circulation pump is electrically connected to the battery management system, and its flow rate is controlled by the battery management system.

[0014] The bidirectional converter further includes a control module, and the control module is electrically connected to the intelligent microgrid controller, receives the switching instruction of the intelligent microgrid controller, and controls the bidirectional converter to switch between grid-connected / off-grid modes.

[0015] The intelligent microgrid controller is electrically connected to the 380V power distribution section of the coal-fired power plant to monitor the voltage status of the power distribution section in real time; when it detects a power failure in the power distribution section, the intelligent microgrid controller sends a disconnection instruction to the grid connection circuit breaker and sends an off-grid power supply instruction to the bidirectional converter to achieve a switch to the vanadium redox flow battery power supply mode within ≤50ms.

[0016] Each vanadium redox flow battery stack, positive and negative electrolyte storage tank, and electrolyte circulation pump of the vanadium redox flow battery system adopt a modular design and are integrated in a container; the bidirectional converter also adopts a modular design and is connected to the container of the vanadium redox flow battery system through a fast cable to achieve flexible combination and expansion.

[0017] The leakage monitoring component of the safety protection device includes a sensor installed at the connection between the electrolyte storage tank and the pipeline. The sensor is electrically connected to the intelligent microgrid controller and triggers an alarm signal when a leakage is detected.

[0018] A DC circuit breaker is provided between the DC output terminal of the vanadium redox flow battery system and the DC side interface of the bidirectional converter. The DC circuit breaker is electrically connected to the intelligent microgrid controller and is controlled by the intelligent microgrid controller to switch on and off.

[0019] The AC side interface of the bidirectional converter is connected to the grid-connected circuit breaker through a filter device, which is used to suppress AC side harmonics.

[0020] Compared with the prior art, the advantages of this utility model are:

[0021] Compared to traditional diesel emergency power supplies, this invention achieves seamless switching at the millisecond level (≤50ms) through a multi-modal collaborative control strategy, solving the problem of long switching delays in traditional emergency power supplies and ensuring stable power supply to critical equipment during plant power outages. Its vanadium redox flow battery boasts high intrinsic safety, with no risk of thermal runaway and no pollutant emissions. The electrolyte is recyclable, mitigating the safety and environmental hazards associated with diesel storage. Furthermore, the system can operate collaboratively with the low-voltage plant power system, assisting in peak shaving and optimizing energy storage scheduling to improve economic efficiency during normal operation, and independently handling loads during faults. Combined with the modular design's ease of maintenance, scalability, and convenient transportation and installation, it significantly improves the reliability, response speed, environmental friendliness, and system flexibility of emergency power supply, effectively ensuring the safe and stable operation of critical equipment in coal-fired power plants. Attached Figure Description

[0022] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0023] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0024] Figure 1 This is a diagram of the overall system architecture of this utility model.

[0025] Among them: 1 is a full vanadium redox flow battery system, 2 is a bidirectional converter, and 3 is a grid-connected circuit breaker. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. These descriptions are only for further illustrating the features and advantages of this utility model, and not for limiting the claims of this utility model. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0028] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0029] This embodiment provides a high-reliability emergency power supply system for coal-fired power plants based on vanadium redox flow batteries. When the 380V low-voltage plant power system of the coal-fired power plant is operating normally, the intelligent microgrid controller monitors the voltage and load status of the distribution section in real time. The system is connected to the plant power system through the grid-connected circuit breaker 3, and the vanadium redox flow battery system 1 is connected to the grid via a bidirectional converter 2. At this time, the intelligent microgrid controller, in combination with the grid-connected electricity price period and load forecast, controls the bidirectional converter 2 to convert the plant power system's electrical energy into DC power during low electricity price periods to charge the vanadium redox flow battery system 1. The electrolyte in the positive and negative electrode electrolyte storage tanks is transported to the stack through a circulation pump, where it stores electrical energy through vanadium ion oxidation-reduction reaction. During high electricity price periods, the vanadium redox flow battery system 1 is controlled to discharge, and the electrolyte is converted into AC power by the bidirectional converter 2 and injected into the grid to assist in peak shaving and reduce operating costs, while reserving emergency power supply capacity. During operation, the leakage monitoring component of the safety protection device monitors the electrolyte storage tank and pipeline in real time, and the battery management system monitors the stack status and electrolyte parameters to ensure system safety. When a power outage occurs in the plant's auxiliary power system, the intelligent microgrid controller detects an abnormal bus voltage within ≤50ms and immediately sends a disconnect command to the grid-connected circuit breaker 3. At the same time, it sends an off-grid mode switching command to the bidirectional converter 2. The bidirectional converter 2 quickly switches to off-grid power supply mode, and the vanadium redox flow battery system 1 supplies DC power to the bidirectional converter 2 through its DC output terminal. After conversion, the DC power independently supplies power to key loads such as the power plant's DCS control system, circulating water pumps, and lubrication oil station. During this period, the intelligent microgrid controller continuously monitors the main power supply status and the emergency power supply system's operating status, and the safety protection devices simultaneously ensure that the system is leak-free and free of safety hazards until the plant's auxiliary power system returns to normal.

[0030] The above description only describes the preferred embodiments of the present utility model. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model, and all such changes should be included within the protection scope of the present utility model.

Claims

1. A high-reliability emergency power supply system for coal-fired power plants based on vanadium redox flow batteries, characterized in that: include: The vanadium redox flow battery system (1) includes multiple vanadium redox flow battery stacks, positive and negative electrolyte storage tanks, electrolyte circulation pumps, and a battery management system. The positive and negative electrode electrolyte storage tanks are connected to the vanadium redox flow battery stack via an electrolyte circulation pump for supplying electrolyte to the stack; the power output terminal of the vanadium redox flow battery stack generates DC output. The bidirectional converter (2) includes a DC side interface and an AC side interface. Its DC side interface is electrically connected to the DC output terminal of the vanadium redox flow battery system (1) and is used to convert the DC power output by the vanadium redox flow battery into AC power. The grid-connected circuit breaker (3) has one end electrically connected to the AC side interface of the bidirectional converter (2), and the other end is used to electrically connect to the 380V power distribution section of the coal-fired power plant. The intelligent microgrid controller is electrically connected to the battery management system, bidirectional converter (2) and grid-connected circuit breaker (3) of the vanadium redox flow battery system (1) respectively, and is used to monitor the system status and control power switching; Safety protection devices include a leak monitoring component connected to the electrolyte storage tank, a fire-fighting component that is compatible with the vanadium redox flow battery system (1) and the bidirectional converter (2), and a protective cabinet that encloses each device.

2. The high-reliability emergency power supply system for coal-fired power plants based on vanadium redox flow batteries according to claim 1, characterized in that: In the vanadium redox flow battery system (1), multiple vanadium redox flow battery stacks are connected in parallel or in series. Each stack has a built-in ion exchange membrane and electrodes, and the electrolyte is sealed by a sealing component. The electrolyte circulation pump is electrically connected to the battery management system, and its flow rate is controlled by the battery management system.

3. The high-reliability emergency power supply system for coal-fired power plants based on vanadium redox flow batteries according to claim 1, characterized in that: The bidirectional converter (2) also includes a control module, which is electrically connected to the smart microgrid controller, receives the switching command from the smart microgrid controller, and controls the bidirectional converter to switch between grid-connected and off-grid modes.

4. A high-reliability emergency power supply system for coal-fired power plants based on vanadium redox flow batteries according to claim 1, characterized in that: The intelligent microgrid controller is electrically connected to the 380V distribution section of the coal-fired power plant and monitors the voltage status of the distribution section in real time. When the power loss of the distribution section is detected, the intelligent microgrid controller sends a disconnection command to the grid-connected circuit breaker (3) and sends an off-grid power supply command to the bidirectional converter (2) to achieve switching to the full vanadium redox flow battery power supply mode within ≤50ms.

5. A high-reliability emergency power supply system for coal-fired power plants based on vanadium redox flow batteries according to claim 1, characterized in that: The vanadium redox flow battery system (1) is modularly designed and integrated into a container for each vanadium redox flow battery stack, positive and negative electrode electrolyte storage tank, and electrolyte circulation pump. The bidirectional converter (2) is also modularly designed and is connected to the container of the vanadium redox flow battery system (1) via a fast cable to achieve flexible combination and expansion.

6. A high-reliability emergency power supply system for coal-fired power plants based on vanadium redox flow batteries according to claim 1, characterized in that: The leakage monitoring component of the safety protection device includes a sensor installed at the connection between the electrolyte storage tank and the pipeline. The sensor is electrically connected to the intelligent microgrid controller and triggers an alarm signal when a leakage is detected.

7. A high-reliability emergency power supply system for coal-fired power plants based on vanadium redox flow batteries according to claim 1, characterized in that: A DC circuit breaker is provided between the DC output terminal of the all-vanadium redox flow battery system (1) and the DC side interface of the bidirectional converter (2). The DC circuit breaker is electrically connected to the intelligent microgrid controller and is controlled by the intelligent microgrid controller to switch on and off.

8. A high-reliability emergency power supply system for coal-fired power plants based on vanadium redox flow batteries according to claim 1, characterized in that: The AC side interface of the bidirectional converter (2) is connected to the grid-connected circuit breaker (3) through a filter device, which is used to suppress AC side harmonics.

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