Direct-current micro-grid fault rapid positioning and isolating system and direct-current micro-grid fault rapid positioning and isolating method

Abstract

The invention relates to the technical field of power systems and automatic control, in particular to a direct-current micro-grid fault quick positioning and isolating system and method, which can quickly and accurately position a fault point in a direct-current micro-grid and immediately trigger a circuit breaker for isolation by monitoring voltage drop and current direction. And the influence of faults on the system is effectively reduced. According to the invention, the power supply reliability and stability of the DC micro-grid are improved in a mode of rapidly positioning and isolating faults, and reliable operation and safety guarantee are provided for the application of the DC micro-grid in small DC micro-grids such as families and commercial buildings and in larger-range scenes such as industrial parks and communities.

Description

Technical Field

[0001] The present invention relates to the field of power system and automation control technology, and in particular to a system and method for quickly locating and isolating a fault in a direct current microgrid. Background Art

[0002] A DC microgrid is a small intelligent power distribution network composed of direct current. With the transformation of the energy structure and the development of distributed energy, DC microgrid systems are increasingly used in power systems due to their high efficiency, flexibility and strong scalability.

[0003] A DC microgrid system usually includes a variety of distributed power sources, such as wind power generation, photovoltaic power generation, etc., as well as energy storage devices and DC loads. These system components are connected to the DC bus through power electronic converters to form a complex power network.

[0004] However, during the operation of the DC microgrid system, system components may fail due to equipment aging, environmental factors or improper operation, which will not only affect the normal operation of the system, but may also cause equipment damage and even lead to safety accidents.

[0005] Based on the above reasons, the present invention designs a DC microgrid fault rapid location and isolation system and method, which quickly and accurately locates the fault point of the DC microgrid by monitoring the voltage drop and current direction, and then isolates it immediately to reduce the impact on system components. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a system and method for rapid fault location and isolation of a DC microgrid, which can quickly and accurately locate the fault point of the DC microgrid by monitoring the voltage drop and current direction, and then immediately isolate it to reduce the impact on system components.

[0007] In order to achieve the above-mentioned object, the present invention provides a DC microgrid fault rapid location and isolation system, including a host computer, an AC power grid, a wind power generation module, a photovoltaic power generation module, a DC / DC module, an AC / DC module, a DC bus, an intelligent monitoring and protection module, an energy storage battery and a DC load; The upper computer is connected to each intelligent monitoring and protection module by communication. The DC bus is connected to the intelligent monitoring and protection module and then to the DC / DC module and the AC / DC module; the AC power grid is first connected to the intelligent monitoring and protection module and then to the AC / DC module; the wind power generation module is first connected to the intelligent monitoring and protection module and then to the AC / DC module; the photovoltaic power generation module is first connected to the intelligent monitoring and protection module and then to the DC / DC module; the energy storage battery is first connected to the intelligent monitoring and protection module and then to the DC / DC module; the DC load is first connected to the intelligent monitoring and protection module and then to the DC / DC module.

[0008] The communication methods between the host computer and each intelligent monitoring and protection module include RS232, RS-485 and TCP / IP protocols.

[0009] The main body of the host computer consists of indicator lights and a control panel.

[0010] The indicator light is green when it is normally on, and turns red when a fault occurs in the branch it represents.

[0011] There is a system circuit diagram in the control panel. When the circuit is normal, the system circuit diagram is green. When a fault occurs, the faulty branch in the system circuit diagram turns red, which is used to accurately find the branch where the fault occurs.

[0012] The intelligent monitoring and protection module includes a voltage and current acquisition module, a relay module and a communication module.

[0013] A method for quickly locating and isolating a DC microgrid fault comprises the following steps: S1, when the DC microgrid system is started, the intelligent monitoring and protection module collects data on circuit voltage and current for real-time fault detection; S2, when abnormal parameters are detected in step S1, the intelligent monitoring and protection module automatically starts the fault detection program; S3, the intelligent monitoring and protection module compares the current and voltage parameters of each branch in the system circuit through the branch comparison method, quickly locates the fault point, and automatically cuts off the power supply at the fault point to prevent the fault from spreading to the entire system; S4, when the system resumes operation after confirming fault isolation, and logs are recorded and reports are generated, the fault information is reported to the host computer for further analysis and processing by the operation and maintenance personnel.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses a branch comparison method to collect and detect data on the voltage and current of each branch in the DC microgrid system through an intelligent monitoring protection module. When an abnormal situation is found, the power supply of the fault point is cut off in time to prevent the fault from spreading, thereby protecting the entire microgrid system. Relevant fault logs are collected and fed back in a timely and comprehensive manner, thereby significantly improving the power supply reliability and stability of the DC microgrid. The present invention is suitable for DC microgrid systems of different sizes and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the method flow of the present invention.

[0016] Figure 2 This is a schematic diagram of the structure of the DC microgrid system of the present invention. DETAILED DESCRIPTION

[0017] The present invention will now be further described with reference to the accompanying drawings.

[0018] See also Figure 2 , this embodiment provides a DC microgrid fault rapid location and isolation system, the system includes a host computer, an AC power grid, a wind power generation module, a photovoltaic power generation module, a DC / DC module, an AC / DC module, a DC bus, an intelligent monitoring and protection module, an energy storage battery and a DC load.

[0019] Among them, the host computer is connected to each intelligent monitoring and protection module through a communication module to receive fault information, display system status and perform remote control. The host computer can communicate with the intelligent monitoring and protection module using RS232, RS-485 or TCP / IP protocol to ensure the accuracy and reliability of data transmission. The indicator light and control panel of the host computer are designed with an intuitive display interface. The indicator light is green when it is normally lit and turns red when the branch it represents fails. The control panel displays a system circuit diagram. The circuit diagram is green when the circuit is normal. When a fault occurs, the faulty branch will turn red. The operation and maintenance personnel can accurately find the branch where the fault occurs, which is convenient for timely processing.

[0020] As one of the external power sources of the system, the AC grid is connected to the DC bus through the intelligent monitoring and protection module and the AC / DC module to provide a stable AC power supply for the system. The AC grid generally uses 380V AC. As distributed power sources, the wind power generation module and the photovoltaic power generation module are connected to the DC bus through the intelligent monitoring and protection module and the AC / DC module (wind power generation) or DC / DC module (photovoltaic power generation) to provide renewable energy for the system. The DC / DC module and the AC / DC module are used to convert DC or AC of different voltage levels into the DC required by the system to ensure voltage matching and stable operation between the components. The above-mentioned DC / DC module and AC / DC module generally use a rated power of 100KW. The voltage of the DC bus is generally 750V. As the core part of the system, it connects the distributed power sources, energy storage devices and DC loads to realize the transmission and distribution of electric energy.

[0021] As the main fault location and isolation intelligent monitoring and protection modules are distributed in each key node of the system, responsible for voltage and current data collection, fault detection and isolation. Each intelligent monitoring and protection module set in the system includes a voltage and current acquisition module, a relay module and a communication module to achieve comprehensive monitoring and protection functions.

[0022] The energy storage battery is used to store excess electrical energy and release it when needed to maintain the stable operation of the system. It is connected to the DC bus through the intelligent monitoring protection module and the DC / DC module to ensure efficient utilization and management of the energy storage battery. The energy storage battery specification is 50kW / 100kWh.

[0023] As the electrical equipment of the system, the DC load is connected to the DC bus through the intelligent monitoring and protection module and the DC / DC module to obtain the required power supply. The load is powered by 48 / 375 / 750V, and the voltage level is converted by the load DC / DC module before use.

[0024] See also Figure 1 Based on the above-mentioned DC microgrid fault rapid location and isolation system, this embodiment provides a DC microgrid fault rapid location and isolation method, which specifically includes the following steps: When the DC microgrid system is started, the intelligent monitoring and protection module starts immediately, and uses its built-in voltage and current acquisition module to collect voltage and current data of each branch in real time, providing basic data for subsequent fault detection. The intelligent monitoring and protection module continuously monitors the collected data and judges abnormal parameters through preset algorithms and thresholds. Once an abnormality is found, the fault detection program is immediately triggered and the fault handling process is entered. After the fault detection program is started, the intelligent monitoring and protection module uses the branch comparison method to compare and analyze the current and voltage parameters of each branch, and quickly locates the branch where the fault is by comparing the data differences between different branches.

[0025] Once the fault point is determined, the intelligent monitoring and protection module immediately controls the corresponding circuit breaker action through the relay module, automatically cuts off the power supply of the fault branch, effectively prevents the fault from spreading to the entire system, and ensures the stable operation of the system. After confirming that the fault has been isolated, the system attempts to restore the normal operation of other non-faulty parts. At the same time, the intelligent monitoring and protection module records the fault information, generates a fault report, and uploads the report to the host computer for operation and maintenance personnel to review and analyze. After the host computer receives the fault report, the operation and maintenance personnel can view the fault details through the indicator light and control panel of the host computer, conduct further analysis and processing, so as to take appropriate measures in time.

[0026] The above are only preferred embodiments of the present invention, which are only used to help understand the method and core ideas of the present application. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

[0027] The present invention solves the shortcomings of the prior art DC microgrid system in that the system components fail due to equipment aging, environmental factors or improper operation, which in turn affects the normal operation of the system and even causes equipment damage and safety accidents. By monitoring the voltage drop and current direction, the fault point in the DC microgrid can be quickly and accurately located, and the circuit breaker can be immediately triggered for isolation, effectively reducing the impact of the fault on the system. The method of quickly locating and isolating faults by the present invention improves the power supply reliability and stability of the DC microgrid, and also provides reliable operation and safety guarantees for the application of DC microgrids in small DC microgrids such as homes and commercial buildings, as well as in larger scenarios such as industrial parks and communities.

Claims

1. A DC microgrid fault rapid location and isolation system, characterized in that: Including host computer, AC power grid, wind power generation module, photovoltaic power generation module, DC / DC module, AC / DC module, DC bus, intelligent monitoring and protection module, energy storage battery and DC load; The host computer is connected to each of the intelligent monitoring and protection modules by means of communication; the DC bus is connected to the intelligent monitoring and protection module and then to the DC / DC module and the AC / DC module; the AC power grid is first connected to the intelligent monitoring and protection module and then to the AC / DC module; the wind power generation module is first connected to the intelligent monitoring and protection module and then to the AC / DC module; the photovoltaic power generation module is first connected to the intelligent monitoring and protection module and then to the DC / DC module; the energy storage battery is first connected to the intelligent monitoring and protection module and then to the DC / DC module; the DC load is first connected to the intelligent monitoring and protection module and then to the DC / DC module.

2. The DC microgrid fault rapid location and isolation system according to claim 1 is characterized in that: The communication methods between the host computer and each of the intelligent monitoring and protection modules include RS232, RS-485 and TCP / IP protocols.

3. The DC microgrid fault rapid location and isolation system according to claim 1 is characterized in that: The main body of the host computer is composed of an indicator light and a control panel.

4. The DC microgrid fault rapid location and isolation system according to claim 3 is characterized in that: The indicator light is green when it is normally on, and turns red when a fault occurs in the branch it represents.

5. The DC microgrid fault rapid location and isolation system according to claim 3 is characterized in that: The control panel includes a system circuit diagram. When the circuit is normal, the system circuit diagram is green. When a fault occurs, the fault branch in the system circuit diagram turns red, which is used to accurately find the branch where the fault occurs.

6. The DC microgrid fault rapid location and isolation system according to claim 1, characterized in that: The intelligent monitoring and protection module includes a voltage and current acquisition module, a relay module and a communication module.

7. A method for rapid fault location and isolation of a DC microgrid, characterized in that: The following steps are involved: S1, when the DC microgrid system is started, the intelligent monitoring and protection module collects data of circuit voltage and current for real-time fault detection; S2, when abnormal parameters are detected in step S1, the intelligent monitoring and protection module automatically starts a fault detection program; S3, the intelligent monitoring and protection module compares the current and voltage parameters of each branch in the system circuit through the branch comparison method, quickly locates the fault point, and automatically cuts off the power supply of the fault point to prevent the fault from spreading to the entire system; S4, when the system resumes operation after confirming the fault isolation, and logs are recorded and a report is generated, the fault information is reported to the host computer for further analysis and processing by the operation and maintenance personnel.

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