Power distribution network distributed new energy bearing capacity calculation system based on power grid graph model

Abstract

The invention discloses a power distribution network distributed new energy bearing capacity calculation system based on a power grid graph model, which is characterized in that the power distribution network distributed new energy bearing capacity calculation system is deployed in an intelligent fusion terminal, and the outlet voltage of a console area is comprehensively regulated and controlled through a photovoltaic inverter and a reactive power compensation device of the console area; reactive compensation is optimized to improve the power supply quality of a terminal user; the system specifically comprises the following two control modes: the system is composed of an intelligent fusion terminal, a reactive compensation controller, a capacitor bank, an intelligent circuit breaker, a photovoltaic controller, a photovoltaic inverter, an intelligent electric meter and a power distribution main station. According to the system, the distributed photovoltaic can be accessed to the maximum capacity of the power grid at each node, observable and measurable bearing capacity of the distributed photovoltaic is realized, and coordinated development of the distributed photovoltaic, the load and the power grid is further guaranteed.

Description

Technical Field

[0001] The invention relates to the field of distributed renewable energy technology, and in particular to a distributed renewable energy carrying capacity calculation system for a distribution network based on a power grid model. Background Art

[0002] Among the existing technologies, new energy sources represented by photovoltaics and wind power have developed rapidly, especially distributed photovoltaics, which have experienced explosive growth. The regional power supply structure, load characteristics, and control methods are constantly changing. The development of sources and loads is not matched, and the urban-rural distribution is unbalanced. Some areas have problems such as insufficient regulation capacity, limited reverse power, and excessive voltage deviation. In some areas, 110 kV substations and lines have overloaded, which has not been realized in the vicinity and has also brought about grid safety risks. In order to accurately understand the carrying capacity of the current power grid, avoid blind investment and construction and waste of resources, and promote the spatial matching of sources and loads, governments at all levels and power supply companies have successively carried out carrying capacity assessment and analysis.

[0003] However, currently, offline calculation data is generally collected offline by county companies and summarized by municipal companies. There are many human factors, and the accuracy of the data is difficult to verify. The calculation scenario used is single and cannot adapt to personalized needs. At the same time, the current online calculation of carrying capacity is mainly aimed at the current state, and there is currently no system for planning or simulation state carrying capacity calculation. This paper proposes a method for calculating the distributed new energy carrying capacity of a selected distribution network range by using existing models, graphics, data and other resources of the power grid and a visual interface interaction method, which reduces the difficulty of operation, improves user satisfaction, and provides support for the rapid development of distributed new energy.

[0004] In the current existing technology, after obtaining the data of the on-load voltage-changing transformer in the substation area, the voltage data of the terminal user is obtained through the concentrator, and then the voltage is adjusted by controlling the gear of the on-load voltage-changing transformer in the substation area. However, the defects of this method are: the traditional voltage and reactive power integrated control is mainly implemented in substations at all levels, and there are the following shortcomings: the substation control area is large, and the needs of users in each substation area cannot be taken into account at the same time; the single capacitor group capacity is too large, and the operation adjustment is difficult. The level of voltage stability maintained by the on-load voltage-changing switch of the transformer is poor. Summary of the invention

[0005] The purpose of the present invention is to solve the deficiencies of the prior art and propose a distributed new energy carrying capacity calculation system for distribution network based on power grid model, which is composed of intelligent fusion terminal, reactive power compensation controller, capacitor bank, intelligent circuit breaker, photovoltaic controller, photovoltaic inverter, intelligent meter and distribution master station. The system enables distributed photovoltaic to access the maximum capacity of the power grid at each node, realizes the observable and measurable carrying capacity of distributed photovoltaic, and thus ensures the coordinated development of distributed photovoltaic, load and power grid.

[0006] A distributed new energy carrying capacity calculation system for a distribution network based on a power grid model of the present invention comprises:

[0007] The distributed new energy carrying capacity calculation system of the distribution network is deployed in the intelligent fusion terminal. It controls the photovoltaic inverter and reactive power compensation device in the control area to comprehensively adjust the output voltage of the distribution area, optimize reactive power compensation to improve the power supply quality of end users. It specifically includes the following two control modes:

[0008] Remote mode: In this mode, the distribution master station sends data instructions such as the output voltage of the substation to the intelligent fusion terminal based on the collected user data of the substation, and the intelligent fusion terminal performs corresponding actions according to the received instructions;

[0009] On-site mode: In this mode, the voltage over-limit management method of the substation microgrid automatically generates a voltage control strategy based on the collected substation user data, and controls the photovoltaic inverter and reactive power compensation device in the substation to adjust the substation outlet voltage value and the upper and lower limits of reactive power compensation.

[0010] Preferably, the system has the functions of electrical quantity monitoring and early warning, and the intelligent fusion terminal is connected to the photovoltaic controller, reactive power compensation device, and intelligent circuit breaker respectively through HPLC.

[0011] Preferably, the intelligent fusion terminal in the system sends messages to the opposite device according to the agreed modbus and mqtt protocols, reads the electrical quantity information of the photovoltaic inverter and reactive compensation device in real time and sends it to the data center. The data includes three-phase voltage and current, active and reactive power, power factor, three-phase total harmonic distortion rate, reactive compensation capacitor switching status, and equipment fault alarm.

[0012] Preferably, the data center carried by the system uploads the above-mentioned electrical quantities to the distribution master station in a timed or variable manner, thereby realizing the collection of node electrical quantity data of the intelligent distribution station area, power supply quality alarm of the station area, and operating status monitoring of the terminal equipment; and the distribution master station extracts the uploaded data for visual display.

[0013] Preferably, the voltage over-limit management method of the substation microgrid in the intelligent fusion terminal obtains the data instruction issued by the distribution master station from the data center; the data instruction issued by the distribution master station includes the upper and lower limits of voltage, the target voltage value, the upper and lower limits of reactive compensation and the parameters of the reactive compensation device; wherein the upper and lower limits of voltage and the upper and lower limits of reactive compensation have time marks,

[0014] It includes: dividing a day into several time periods. When the system runs to the mark time point, the microgrid voltage over-limit management method begins to implement the voltage upper and lower limit settings of the corresponding time period, the upper and lower limit settings of reactive power compensation, etc.; the user voltage fluctuations are different in different time periods. The distribution master station refers to the collected user voltage data and issues time-based voltage regulation instructions.

[0015] The advantages and technical effects of the present invention are:

[0016] The present invention provides a distributed new energy carrying capacity calculation system for distribution network based on power grid model, which utilizes functions such as intelligent fusion terminal information collection, IoT agent, edge computing, etc., supplemented by intelligent reactive power compensation device, photovoltaic controller, photovoltaic inverter, smart meter and distribution master station, and proposes a voltage over-limit management method for distribution network substation microgrid with low-voltage grid-connected distributed photovoltaic participation. The method innovatively connects to the distributed photovoltaic resources connected to the low-voltage grid in the substation, and manages the voltage over-limit problem of the substation caused by the large-scale development of distributed photovoltaic by adjusting the grid-connected voltage and reactive power of distributed photovoltaic, thus broadening the application scenarios of distributed photovoltaic power generation and better improving the application potential of distributed photovoltaic power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a flow chart of the method. DETAILED DESCRIPTION

[0018] The embodiments of the invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the invention, and cannot be understood as limiting the invention.

[0019] A distributed new energy carrying capacity calculation system for a distribution network based on a power grid model of the present invention comprises:

[0020] The distributed new energy carrying capacity calculation system of the distribution network is deployed in the intelligent fusion terminal. It controls the photovoltaic inverter and reactive power compensation device in the control area to comprehensively adjust the output voltage of the distribution area, optimize reactive power compensation to improve the power supply quality of end users. It specifically includes the following two control modes:

[0021] Remote mode: In this mode, the distribution master station sends data instructions such as the output voltage of the substation to the intelligent fusion terminal based on the collected user data of the substation, and the intelligent fusion terminal performs corresponding actions according to the received instructions;

[0022] On-site mode: In this mode, the voltage over-limit management method of the substation microgrid automatically generates a voltage control strategy based on the collected substation user data, and controls the photovoltaic inverter and reactive power compensation device in the substation to adjust the substation outlet voltage value and the upper and lower limits of reactive power compensation.

[0023] Preferably, the system has the functions of electrical quantity monitoring and early warning, and the intelligent fusion terminal is connected to the photovoltaic controller, reactive power compensation device, and intelligent circuit breaker respectively through HPLC.

[0024] Preferably, the intelligent fusion terminal in the system sends messages to the opposite device according to the agreed modbus and mqtt protocols, reads the electrical quantity information of the photovoltaic inverter and reactive compensation device in real time and sends it to the data center. The data includes three-phase voltage and current, active and reactive power, power factor, three-phase total harmonic distortion rate, reactive compensation capacitor switching status, and equipment fault alarm.

[0025] Preferably, the data center carried by the system uploads the above-mentioned electrical quantities to the distribution master station in a timed or variable manner, thereby realizing the collection of node electrical quantity data of the intelligent distribution station area, power supply quality alarm of the station area, and operating status monitoring of the terminal equipment; and the distribution master station extracts the uploaded data for visual display.

[0026] Preferably, the voltage over-limit management method of the substation microgrid in the intelligent fusion terminal obtains the data instruction issued by the distribution master station from the data center; the data instruction issued by the distribution master station includes the upper and lower limits of voltage, the target voltage value, the upper and lower limits of reactive compensation and the parameters of the reactive compensation device; wherein the upper and lower limits of voltage and the upper and lower limits of reactive compensation have time marks,

[0027] It includes: dividing a day into several time periods. When the system runs to the mark time point, the microgrid voltage over-limit management method begins to implement the voltage upper and lower limit settings of the corresponding time period, the upper and lower limit settings of reactive power compensation, etc.; the user voltage fluctuations are different in different time periods. The distribution master station refers to the collected user voltage data and issues time-based voltage regulation instructions.

[0028] In order to more clearly illustrate the specific implementation mode of the present invention, an embodiment is provided below:

[0029] like Figure 1 As shown in the figure, the voltage over-limit control method of the substation microgrid is composed of an intelligent fusion terminal, a reactive power compensation controller, a capacitor bank, an intelligent circuit breaker, a photovoltaic controller, a photovoltaic inverter, a smart meter and a distribution master station.

[0030] The voltage over-limit management method of the substation microgrid is deployed in the intelligent fusion terminal. The photovoltaic inverter and reactive compensation device in the control area are used to comprehensively adjust the substation outlet voltage, optimize reactive compensation, and improve the power supply quality of the end users. This method has two operating modes. One is the remote mode. In this mode, the distribution master station sends data instructions such as the substation outlet voltage to the intelligent fusion terminal based on the collected substation user data, and the intelligent fusion terminal performs corresponding actions according to the received instructions. The other is the local mode. In this mode, the voltage over-limit management method of the substation microgrid automatically generates a voltage control strategy based on the collected substation user data, and controls the photovoltaic inverter and reactive compensation device in the control area to adjust the substation outlet voltage value and the upper and lower limits of reactive compensation.

[0031] The voltage over-limit management method of the microgrid in the substation area has the functions of electrical quantity monitoring and early warning. The intelligent fusion terminal is connected to the photovoltaic controller, reactive compensation device, and intelligent circuit breaker through HPLC. The intelligent fusion terminal sends messages to the end device according to the agreed modbus and mqtt protocols, reads the electrical quantity information of the photovoltaic inverter and reactive compensation device in real time and sends it to the data center. The data includes three-phase voltage and current, active and reactive power, power factor, three-phase harmonic total distortion rate, reactive compensation capacitor switching status, equipment fault alarm, etc. The data center adopts a timed upload or variable upload method to upload the above electrical quantities to the distribution master station, thereby realizing the node electrical quantity data collection of the intelligent distribution substation area, the power supply quality alarm of the substation area, and the operation status monitoring of the terminal equipment. At the same time, the distribution master station can extract the uploaded data for visual display.

[0032] The voltage over-limit management method of the microgrid in the substation in the substation intelligent fusion terminal obtains the data instructions issued by the distribution master station from the data center. The data instructions issued by the distribution master station include the upper and lower limits of voltage, the target voltage value, the upper and lower limits of reactive compensation, and the parameters of the reactive compensation device. Among them, the upper and lower limits of voltage and the upper and lower limits of reactive compensation have time marks, which can divide a day into several time periods. When the system runs to the marked time point, the microgrid voltage over-limit management method begins to execute the upper and lower limits of voltage and reactive compensation in the corresponding time period. The fluctuation of user voltage is different in different time periods. The distribution master station refers to the collected user voltage data and issues instructions for time-divided voltage regulation.

[0033] The key point of the present invention is: first, it is necessary to ensure that the intelligent fusion terminal of the substation has been connected to the distributed photovoltaic resources connected to the low-voltage grid, and the strategy of the voltage over-limit management method of the substation microgrid has been deployed in the intelligent fusion terminal. Then, the intelligent fusion terminal can collect the real-time voltage on the low-voltage side of the substation transformer in real time. When the voltage exceeds the limit, the voltage over-limit management can be completed by adjusting the outlet voltage and reactive power compensation device of the distributed photovoltaic. The substation microgrid voltage over-limit management method also has two operating modes: remote mode and local mode, and the appropriate mode can be selected for control according to the actual situation. In the remote mode, the distribution master station can monitor and control the substation voltage, which improves the controllability of the power system; in the local mode, the substation microgrid voltage over-limit management method automatically generates a voltage control strategy based on the collected voltage data, and then controls the distributed photovoltaic outlet voltage, reactive power output and reactive power compensation device for adjustment, which improves the stability of the substation voltage.

[0034] In addition, the present invention is preferred, in the present invention, the intelligent fusion terminal of the substation area performs data aggregation and instruction forwarding of the distributed photovoltaic and reactive power control devices through HPLC communication, alternative scheme:

[0035] Adopt RS485 line communication, directly connect intelligent fusion terminal, photovoltaic inverter and reactive power control device;

[0036] Using network cable communication, directly connecting the intelligent fusion terminal, photovoltaic inverter and reactive power control device;

[0037] Adopt 4G / 5G / micropower and other wireless communication methods to connect intelligent fusion terminals, photovoltaic inverters and reactive power control devices.

[0038] Finally, all the unexplained parts of the invention adopt mature products and mature technical means in the existing technology.

[0039] In the description of this specification, reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in the embodiment or example of the invention.

[0040] Although embodiments of the invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A distributed renewable energy carrying capacity calculation system for a distribution network based on a power grid model, characterized in that: include: The distributed new energy carrying capacity calculation system of the distribution network is deployed in the intelligent fusion terminal. It controls the photovoltaic inverter and reactive power compensation device in the control area to comprehensively adjust the output voltage of the distribution area, optimize reactive power compensation to improve the power supply quality of end users. It specifically includes the following two control modes: Remote mode: In this mode, the distribution master station sends data instructions such as the output voltage of the substation to the intelligent fusion terminal based on the collected user data of the substation, and the intelligent fusion terminal performs corresponding actions according to the received instructions; On-site mode: In this mode, the voltage over-limit management method of the substation microgrid automatically generates a voltage control strategy based on the collected substation user data, and controls the photovoltaic inverter and reactive power compensation device in the substation to adjust the substation outlet voltage value and the upper and lower limits of reactive power compensation.

2. According to claim 1, a distribution network distributed new energy carrying capacity calculation system based on a power grid model is characterized by: The system has the functions of electrical quantity monitoring and early warning, and the intelligent fusion terminal is connected with the photovoltaic controller, the reactive power compensation device and the intelligent circuit breaker respectively through HPLC.

3. A distribution network distributed new energy carrying capacity calculation system based on power grid model according to claim 2, characterized in that: In the system, the intelligent fusion terminal sends messages to the opposite device according to the agreed Modbus and MQTT protocols, reads the electrical quantity information of the photovoltaic inverter and reactive compensation device in real time and sends it to the data center. The data includes three-phase voltage and current, active and reactive power, power factor, three-phase total harmonic distortion rate, reactive compensation capacitor switching status, and equipment fault alarm.

4. A distribution network distributed new energy carrying capacity calculation system based on a power grid model according to claim 3, characterized in that: The data center carried by the system transmits the above-mentioned electrical quantities to the distribution main station in a scheduled or variable manner, thereby realizing the node electrical quantity data collection of the intelligent distribution station area, the power supply quality alarm of the station area, and the operating status monitoring of the terminal equipment; and the distribution main station extracts the transmitted data for visual display.

5. The distributed new energy carrying capacity calculation system of the distribution network based on the power grid model according to claim 1 is characterized in that: The voltage over-limit management method of the substation microgrid in the intelligent fusion terminal obtains the data instruction issued by the distribution master station from the data center; the data instruction issued by the distribution master station includes the upper and lower limits of voltage, the target voltage value, the upper and lower limits of reactive compensation and the parameters of the reactive compensation device; wherein the upper and lower limits of voltage and the upper and lower limits of reactive compensation have time marks, It includes: dividing a day into several time periods. When the system runs to the mark time point, the microgrid voltage over-limit management method begins to implement the voltage upper and lower limit settings of the corresponding time period, the upper and lower limit settings of reactive power compensation, etc.; the user voltage fluctuations are different in different time periods. The distribution master station refers to the collected user voltage data and issues time-based voltage regulation instructions.

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