Frequency modulation control and on-line monitoring system

Abstract

The invention relates to the technical field of new energy power generation control, and discloses a frequency modulation control and online monitoring system, which comprises an AGC (Automatic Gain Control) system for realizing automatic gain control to stabilize the signal transmission quality of the system, and an FPGA (Field Programmable Gate Array) functional module for high-speed data acquisition and logical operation processing, and the CPU processing module is used for overall planning of data analysis, instruction generation and system cooperative control. According to the invention, the FPGA + CPU hardware architecture is adopted, so that the precision requirement of power grid frequency sampling can be ensured, and the precision of the calculated grid-connected point power information can be ensured, thereby obtaining the high-precision power adjusting quantity, adjusting the new energy station according to the power adjusting quantity, and carrying out real-time adjustment control on the new energy station. The requirement for primary frequency modulation of the new energy station is met, and the operation stability of the new energy station is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new energy power generation control technology, in particular to a frequency modulation control and online monitoring system. BACKGROUND

[0002] With the transformation of global energy structure to clean and low-carbon, new energy power generation technologies such as photovoltaic and wind power have been widely applied, and the proportion of new energy station grid-connected capacity in the power system continues to increase. However, new energy power generation has inherent characteristics of strong intermittency and volatility (such as photovoltaic output affected by light intensity, wind power output affected by wind speed change), and after a large number of new energy is connected to the grid, the proportion of traditional thermal power and other adjustable power sources decreases relatively, resulting in reduced inertia and weakened frequency modulation capacity of the power system, and the frequency stability of the power grid faces severe challenges - when the power load and power generation capacity are out of balance, frequency drop, frequency rise or continuous oscillation may occur, and if the frequency stability cannot be restored in time through frequency modulation control, serious accidents such as damage to power grid equipment and large-scale power outages may occur, threatening the safe and reliable operation of the power system.

[0003] Currently, the technical scheme of new energy station participating in power grid frequency modulation has become a research hotspot in the industry, but the existing technology still has many deficiencies in practical application, and it is difficult to meet the requirements of the power grid for frequency modulation response speed, control accuracy and operation reliability. The specific problems are as follows:

[0004] 1. Insufficient real-time and accuracy of data acquisition:

[0005] In the existing new energy station frequency modulation system, the acquisition of key data such as grid-connected point voltage and current, and active power of power generation unit mainly depends on traditional single-chip microcomputers or low-speed data acquisition modules, which have problems such as low sampling frequency, poor sampling accuracy, and weak signal processing capability. On the one hand, low sampling frequency cannot completely capture the instantaneous fluctuation of grid frequency, and may miss the best frequency modulation opportunity; on the other hand, insufficient sampling accuracy and lack of effective noise filtering processing result in large errors in the collected frequency data and power data, which further causes deviation of subsequent frequency modulation control instruction calculation, leading to "over-regulation" or "under-regulation", which not only cannot effectively stabilize the grid frequency, but also may exacerbate the power fluctuation of the grid. At the same time, the data transmission of some systems relies on low-speed communication bus, and the data transmission delay exceeds 100 μs, further causing frequency modulation response lag, which is difficult to meet the requirement of "millisecond-level response" of the power grid for frequency modulation;

[0006] 2. Poor coordination between primary frequency modulation and AGC control:

[0007] In existing systems, primary frequency modulation and AGC are mostly independent control logics, lacking effective coordination mechanisms. When there are both frequency deviation and load regulation requirements in the power grid, control command conflicts may easily occur, for example, the primary frequency modulation requires increasing the power generation to increase the grid frequency, while the AGC requires reducing the power to match the scheduled load, and the opposite adjustment leads to a sharp fluctuation of the power output of the new energy station, which cannot stabilize the grid frequency and may exceed the power regulation capacity of the generating unit, causing equipment overload and damage. In addition, some systems do not have a reasonable primary frequency modulation dead zone and difference coefficient configuration function, either because the dead zone is too large to trigger frequency modulation for small frequency deviation, or because the dead zone is too small to cause frequent frequency modulation, increasing equipment wear and power grid disturbance; the fixed difference coefficient cannot dynamically adjust the power regulation increment according to the grid frequency fluctuation amplitude, resulting in insufficient frequency modulation accuracy (such as insufficient regulation for large frequency deviation, and excessive regulation for small frequency deviation). SUMMARY

[0008] The present application aims to provide a frequency modulation control and online monitoring system to solve the problems raised in the background art.

[0009] To achieve the above-mentioned purpose, the present application provides the following technical solution: a frequency modulation control and online monitoring system, comprising an AGC system for realizing automatic gain control to stabilize the signal transmission quality of the system, an FPGA functional module for high-speed data acquisition and logical operation processing, and a CPU processing module for overall data analysis, instruction generation and system collaborative control;

[0010] The AGC system, FPGA functional module and CPU processing module are electrically connected through a high-speed data bus;

[0011] The FPGA functional module is electrically connected with the voltage and current sensors of the grid connection point of the new energy station and the power detection units of each generating unit of the new energy station, and the CPU processing module is electrically connected with the control system of the new energy station through an external communication interface module.

[0012] Preferably, the sampling frequency of the FPGA functional module for the voltage and current of the grid connection point is not less than 5 kHz, and the sampling accuracy reaches 0.1 level, and the sampling interval of the active power of the generating unit is not more than 10 ms; the frequency data is calculated by performing Fourier transform on the collected voltage and current signals, the power data is obtained by filtering and quantizing the signals output by the power detection unit, and the processed frequency data and power data are packaged according to a preset communication protocol and sent to the CPU processing module.

[0013] Preferably, the CPU processing module is internally provided with a data buffer unit and a data analysis unit, the frequency data and the power data are temporarily stored in the data buffer unit, and the effective data is extracted by the data analysis unit; based on a preset frequency modulation control algorithm, in combination with parameters such as the installed capacity of the new energy station, the grid-connected power limit, and the grid frequency deviation threshold, power adjustment data including a target power value, a power adjustment rate, and an adjustment duration are calculated and sent to the control system of the new energy station through an external communication interface module.

[0014] Preferably, the system further comprises a primary frequency modulation active increment calculation module for calculating the active power adjustment increment corresponding to the grid frequency deviation, the primary frequency modulation active increment calculation module is electrically connected to the CPU processing module through an internal data bus, and is internally provided with a frequency deviation detection unit and an increment calculation model.

[0015] Preferably, the primary frequency modulation active increment calculation module compares the grid frequency data with the rated grid frequency through the frequency deviation detection unit to calculate the frequency deviation value; based on a preset primary frequency modulation dead zone and a deviation coefficient, the active power adjustment increment is obtained through the increment calculation model and sent to the CPU processing module.

[0016] Preferably, the system further comprises an AGC coordination control module for coordinating the primary frequency modulation and the AGC control logic, the AGC coordination control module is electrically connected to the CPU processing module through an internal data bus, and is internally provided with a control priority judgment unit and a control instruction correction unit.

[0017] Preferably, the system further comprises a recording module and a human-computer interface module; the recording module is electrically connected to the CPU processing module through a high-speed data interface and is used for recording system operation data and control process data; the human-computer interface module is electrically connected to the CPU processing module through a data interaction line and is used for realizing user interaction, parameter configuration, and state monitoring.

[0018] Preferably, the recording module is internally provided with a data storage unit, a trigger condition setting unit, and a data export unit.

[0019] Preferably, the human-computer interface module comprises a display unit, an input unit, and an alarm unit; the display unit adopts an industrial-grade touch screen, the input unit supports touch and physical key operation, and the alarm unit comprises an audible and visual alarm device.

[0020] Compared with the prior art, the present application provides a frequency modulation control and online monitoring system, which has the following beneficial effects:

[0021] The application cooperates the AGC system, the FPGA function module and the CPU processing module through a collaborative architecture, and designs a high-speed and low-delay connection, so that the system can capture the operation state of the power grid and the new energy station in real time, provide accurate and timely data support for subsequent frequency modulation control, avoid the frequency modulation lag problem caused by independent work of the modules or data transmission delay, and improve the response sensitivity of the system to the frequency change of the power grid. DETAILED DESCRIPTION

[0022] In order to better understand the purpose, structure and function of the application, the frequency modulation control and online monitoring system will be further described in detail below in combination with the drawings.

[0023] The application provides a technical solution: a frequency modulation control and online monitoring system, which comprises an AGC system for realizing automatic gain control to stabilize the signal transmission quality of the system, an FPGA function module for high-speed data acquisition and logical operation processing, and a CPU processing module for overall data analysis, instruction generation and system collaborative control.

[0024] The AGC system, the FPGA function module and the CPU processing module are electrically connected through a high-speed data bus.

[0025] The FPGA function module is electrically connected with the voltage and current sensors of the grid-connected point of the new energy station and the power detection units of each power generation unit of the new energy station, and the CPU processing module is electrically connected with the control system of the new energy station through an external communication interface module.

[0026] The application cooperates the AGC system, the FPGA function module and the CPU processing module through a collaborative architecture, and designs a high-speed and low-delay connection, so that the system can capture the operation state of the power grid and the new energy station in real time, provide accurate and timely data support for subsequent frequency modulation control, avoid the frequency modulation lag problem caused by independent work of the modules or data transmission delay, and improve the response sensitivity of the system to the frequency change of the power grid.

[0027] In this embodiment, the sampling frequency of the grid-connected point voltage and current by the FPGA functional module is not less than 5 kHz, and the sampling accuracy reaches 0.1 level (i.e. measurement error ≤ 0.1%), the sampling frequency can completely capture the instantaneous fluctuation of the grid frequency (such as frequency drop / rapid rise caused by grid failure), and the sampling accuracy of 0.1 level can ensure the accuracy of the voltage and current data, and avoid the deviation of frequency calculation caused by data error; the sampling interval of the active power of the power generation unit is not more than 10 ms, which can track the power output change of the power generation unit in real time, and prevent missing abnormal power fluctuation due to too long sampling interval; the FPGA functional module has a built-in Fourier transform operation unit (using 16-point fast Fourier transform algorithm), which can extract the fundamental frequency component from the complex alternating current signal by performing Fourier transform on the collected voltage and current signal, and accurately calculate the grid frequency data; at the same time, the built-in 8-order low-pass filter and 12-bit ADC quantization unit filter the analog signal output by the power detection unit first, filter out the noise caused by grid harmonics and electromagnetic interference, then convert the analog signal to digital power data through quantization processing, and send the processed frequency data and power data to the CPU processing module after encapsulation according to the preset communication protocol (such as Modbus-RTU, data frame format is 1 start bit + 8 data bits + 1 check bit + 1 stop bit), and add data check code (such as CRC16 check) in the encapsulation process to ensure that there is no packet loss and no error code in data transmission.

[0028] The application adopts high-frequency and high-precision sampling design and signal processing flow, so that the frequency data and power data output by the FPGA functional module have real-time and accuracy, which can provide reliable analysis basis for the CPU processing module, and can also avoid the misissuance of frequency modulation instructions caused by data noise or error, and ensure the accuracy of subsequent power regulation; the communication protocol encapsulation and verification mechanism further ensures the reliability of data transmission, and reduces the risk of system out of control caused by data transmission failure.

[0029] In this embodiment, the CPU processing module is built-in data cache unit and data analysis unit, through the data cache unit temporary storage frequency data and power data, can avoid because data instant influx leads to CPU processing overload, at the same time for subsequent data backtracking analysis provides temporary storage space;Data analysis unit through the preset data format rule (such as analysis frequency data field, power data field, timestamp field), from encapsulation data extraction effective data, eliminate invalid frame (such as check failed data frame);CPU processing module built-in preset frequency modulation control algorithm (such as PID control algorithm), combined with new energy station installed capacity, current grid connected power limit, power grid frequency deviation threshold and other parameters, through algorithm calculation obtained contains target power value, power regulation rate, adjustment duration power regulation data;CPU processing module through external communication interface module sends power regulation data to the control system of new energy station, at the same time receives the instruction execution state feedback by control system, if more than 500 ms no feedback, automatically resend instruction, form closed loop control.

[0030] The design of the data cache and analysis unit adopted in the present application improves the data processing efficiency and anti-interference ability of the CPU processing module, avoiding invalid data occupying computing resources;The professional frequency modulation control algorithm combined with multiple parameters makes the power regulation data meet the power grid frequency modulation demand and adapt to the operation limit of new energy station, avoiding equipment damage caused by power regulation exceeding the station capacity;The closed loop control mechanism ensures that the adjustment instruction can be effectively executed, timely corrects the instruction execution abnormal problem, and improves the reliability and stability of system frequency modulation.

[0031] In this embodiment, it also includes a primary frequency regulation active increment calculation module for calculating the active power regulation increment corresponding to the power grid frequency deviation, which is electrically connected with the CPU processing module through an internal data bus;The module is built-in frequency deviation detection unit and increment calculation model, the frequency deviation detection unit receives the power grid frequency data forwarded by the CPU processing module in real time, compares with the rated power grid frequency, and accurately calculates the frequency deviation value;The increment calculation model automatically calculates the active power regulation increment according to the preset parameters, providing core data support for primary frequency regulation.

[0032] The present application adopts the independent design of the primary frequency regulation active increment calculation module, which separates the increment calculation task of primary frequency regulation from the CPU processing module, reduces the CPU load, and at the same time, the rapid operation ability of the module ensures that the regulation increment can be calculated within 2 ms after the frequency deviation occurs, meeting the millisecond level response requirement of power grid for primary frequency regulation, avoiding missing the best frequency modulation opportunity due to calculation delay, and improving the timeliness of power grid frequency stability.

[0033] In the embodiment, the primary frequency regulation active increment calculation module compares the power grid frequency data with the rated power grid frequency through the frequency deviation detection unit to calculate the frequency deviation value; based on the preset primary frequency regulation dead zone and the regulation difference coefficient, the active power regulation increment is obtained through the increment calculation model; after the calculation is completed, the module sends the active power regulation increment to the CPU processing module through the internal data bus, while the data validity identifier is attached, and after the CPU processing module receives it, the primary frequency regulation instruction is generated based on the increment data.

[0034] The application can avoid frequent system action when the power grid frequency fluctuates slightly, reduce equipment loss and power grid disturbance through the setting of the primary frequency regulation dead zone; the accurate configuration of the regulation difference coefficient ensures that the power regulation increment matches the frequency deviation, which neither leads to poor frequency regulation effect due to insufficient regulation amount nor causes power grid frequency overshoot due to excessive regulation amount; the data validity identifier helps the CPU processing module quickly filter reliable data, avoids generating incorrect instructions based on invalid increments, and further ensures the accuracy of the primary frequency regulation.

[0035] In the embodiment, the AGC coordination control module for coordinating the primary frequency regulation and the AGC control logic is also included, which is electrically connected with the CPU processing module through the internal data bus (such as the SPI bus, transmission rate 10 Mbps) and can receive the AGC control instruction sent by the CPU processing module and the primary frequency regulation active increment calculation module in real time; the built-in control priority judgment unit and the control instruction correction unit in the module can quickly determine the execution priority and correct the instruction when the two control requirements conflict.

[0036] The AGC coordination control module solves the instruction conflict problem caused by the independent work of the primary frequency regulation and the AGC in the traditional system, ensures that the system can execute the optimal control strategy under different working conditions through priority judgment and instruction correction, that is, the frequency stability is prioritized when the power grid frequency deviates urgently, and the load regulation demand of the power grid dispatching is prioritized when the frequency is stable, which improves the adaptation ability of the system to complex power grid working conditions and avoids affecting the safe operation of the power grid due to control conflict.

[0037] In the embodiment, the wave recording module and the human-computer interface module are also included; the wave recording module is electrically connected with the CPU processing module through the high-speed data interface and can receive the system running data and control process data forwarded by the CPU processing module in real time, the data sampling interval can be set, and the default is recorded at 1 ms interval to ensure complete recovery of the system running process; the human-computer interface module is electrically connected with the CPU processing module through the data interaction line, supports the user to configure parameters, monitor the running state and troubleshoot through the module, and can also receive the abnormal information sent by the CPU processing module to remind the user to handle in time.

[0038] The large-capacity and long-life storage design of the recording module can record long-term operation data of the system, which is convenient for tracing analysis after power grid failure (such as restoring the system response process during frequency drop to check the delay reason of regulation), and can also provide historical data support for system control algorithm optimization; the industrial-grade design and convenient operation function of the human-computer interface module reduce the operation and maintenance threshold of the system, and the staff can complete parameter configuration and state monitoring without professional programming knowledge, and the adaptability to harsh environment ensures that the module works stably in new energy stations (such as outdoor photovoltaic power stations and high-altitude wind power stations) for a long time.

[0039] In the embodiment, the recording module is internally provided with a data storage unit, a trigger condition setting unit and a data export unit; when the preset trigger condition is met, the recording module automatically starts recording, records data from 30s before triggering to 60s after triggering, and avoids missing key data due to untimely manual start; when data is exported, time interval filtering and exporting are supported, and the exported file can be directly used for simulation verification by power system analysis software.

[0040] The setting of multiple types of trigger conditions meets the recording needs in different scenarios, ensures that data at key moments such as power grid abnormalities and equipment failures are not lost, the COMTRADE standard data format improves the universality of recording data, is compatible with mainstream power analysis software, and reduces the difficulty of data analysis, and the high-speed data export interface shortens the data extraction time, facilitates the staff to quickly carry out fault troubleshooting and system optimization, and improves the operation and maintenance efficiency.

[0041] In the embodiment, the human-computer interface module includes a display unit, an input unit and an alarm unit; when the system detects an abnormality, the alarm unit is triggered immediately, and the display unit pops up a prompt, and the staff can quickly operate through the input unit.

[0042] It can be understood that the present application is described by some embodiments, and those skilled in the art know that various changes or equivalent replacements can be made to the features and embodiments without departing from the spirit and scope of the present application. In addition, under the guidance of the present application, the features and embodiments can be modified to adapt to specific conditions and materials without departing from the spirit and scope of the present application. Therefore, the present application is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present application are within the scope of the present application.

Claims

1. A frequency modulation control and on-line monitoring system, characterized by: The AGC system is used for realizing automatic gain control to stabilize system signal transmission quality, the FPGA functional module is used for high-speed data acquisition and logical operation processing, and the CPU processing module is used for overall data analysis, instruction generation and system collaborative control. The AGC system, the FPGA functional module and the CPU processing module are electrically connected through a high-speed data bus. The FPGA functional module is electrically connected with a voltage and current sensor of a grid-connected point of a new energy station and a power detection unit of each power generation unit of the new energy station, and the CPU processing module is electrically connected with a control system of the new energy station through an external communication interface module.

2. The frequency modulation control and on-line monitoring system according to claim 1, characterized in that: The sampling frequency of the grid-connected point voltage and current by the FPGA functional module is not less than 5 kHz, and the sampling accuracy reaches 0.1 level, and the sampling interval of the active power of the power generation unit is not more than 10 ms; frequency data are calculated through Fourier transform calculation on the collected voltage and current signals, power data are obtained through filtering and quantization processing on the signals output by the power detection unit, and the processed frequency data and power data are packaged according to a preset communication protocol and sent to the CPU processing module.

3. The frequency modulation control and on-line monitoring system according to claim 1, wherein: The CPU processing module is internally provided with a data buffering unit and a data analysis unit, the frequency data and the power data are temporarily stored through the data buffering unit, and valid data are extracted through the data analysis unit; based on a preset frequency modulation control algorithm, in combination with parameters such as installed capacity of the new energy station, grid-connected power limit, grid frequency deviation threshold and the like, power regulation data containing a target power value, a power regulation rate and a regulation duration are calculated and sent to the control system of the new energy station through the external communication interface module.

4. The frequency modulation control and on-line monitoring system of claim 1, wherein: Further comprising a primary frequency modulation active increment calculation module used for calculating an active power regulation increment corresponding to a grid frequency deviation, the primary frequency modulation active increment calculation module is electrically connected with the CPU processing module through an internal data bus and internally provided with a frequency deviation detection unit and an increment calculation model.

5. The frequency modulation control and on-line monitoring system according to claim 4, characterized in that: The primary frequency modulation active increment calculation module compares the grid frequency data with a rated grid frequency through the frequency deviation detection unit to calculate a frequency deviation value; based on preset primary frequency modulation dead zones and modulation coefficients, an active power regulation increment is obtained through the increment calculation model and sent to the CPU processing module.

6. The frequency modulation control and on-line monitoring system of claim 1, wherein: Further comprising an AGC coordination control module used for coordinating primary frequency modulation and AGC control logic, the AGC coordination control module is electrically connected with the CPU processing module through an internal data bus and internally provided with a control priority judgment unit and a control instruction correction unit.

7. The frequency modulation control and on-line monitoring system of claim 1, wherein: Further comprising a recording module and a human-computer interface module; the recording module is electrically connected with the CPU processing module through a high-speed data interface and used for recording system operation data and control process data; the human-computer interface module is electrically connected with the CPU processing module through a data interaction line and used for realizing user interaction, parameter configuration and state monitoring.

8. The frequency modulation control and on-line monitoring system according to claim 8, characterized in that: The recording module is internally provided with a data storage unit, a trigger condition setting unit and a data export unit.

9. The frequency modulation control and on-line monitoring system of claim 8, wherein: The human-machine interface module comprises a display unit, an input unit and an alarm unit; the display unit adopts an industrial-grade touch screen, the input unit supports touch and physical key operation, and the alarm unit comprises an audible and visual alarm device.