New energy stability coordination controller and control method

Abstract

The invention discloses a new energy stable coordination controller and control method, and the controller comprises a signal collection module which is used for collecting the real-time state data of new energy power generation and the real-time state data of a power distribution network system; and the data processing module is used for receiving, processing and analyzing the data acquired by the signal acquisition module, then sending the processed and analyzed data to a scheduling system, receiving a scheduling instruction matched by the scheduling system according to the processed and analyzed data, and then decomposing the scheduling instruction and issuing the decomposed scheduling instruction to a local controller for execution. According to the scheme, through full-process technical innovation of high-speed acquisition, intelligent verification, safe communication and closed-loop control, defects in new energy access management and control in the prior art are systematically solved, and observability, measurability, controllability and adjustability of a distributed power supply and a power distribution network are realized; and a key technical support is provided for safe, stable and economical operation of the power grid in a high-permeability new energy grid-connected scene.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy, and in particular to a new energy stable coordination controller and a control method. Background Art

[0002] With the advancement of the "dual carbon" goal, new energy power generation systems such as distributed photovoltaics and wind power have been massively connected to the distribution network, changing the traditional one-way power supply mode of the distribution network. The intermittency, volatility, and high-penetration access of new energy power generation have led to complex problems in the distribution network, such as node voltage deviation, harmonic pollution, three-phase imbalance, and failure of relay protection coordination, posing severe challenges to the safe and stable operation and economic dispatching of the power grid.

[0003] In the prior art, the control means for new energy access mainly have the following deficiencies: they cannot accurately capture the transient changes (such as inrush current and voltage flicker) of the new energy power generation system, and lack the ability to synchronously collect multi-dimensional data such as three-phase voltage, current, and harmonics, resulting in a lag in power grid state assessment and difficulty in meeting real-time control requirements; existing systems generally lack a real-time verification mechanism for new energy access constraint conditions, cannot dynamically calculate the regulation margins of active and reactive power, and are difficult to achieve precise control of AVC, AGC, and primary frequency modulation, resulting in a low matching degree between new energy output and grid demand and poor system operation economy. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the control means when new energy is connected to the distribution network in the prior art, which lead to poor utilization of new energy and affect the stable operation of the distribution network, and to provide a new energy stable coordination controller and a control method.

[0005] The purpose of the present invention is achieved through the following technical solutions: A new energy stable coordination controller includes: A signal acquisition module for acquiring real-time status data of new energy power generation and real-time status data of the distribution network system; A data processing module for receiving the data acquired by the signal acquisition module, processing and analyzing it, then sending the processed and analyzed data to the dispatching system, receiving the dispatching instructions matched according to the processed and analyzed data by the dispatching system, and then decomposing and issuing the dispatching instructions to the local controller for execution; The signal acquisition module includes an acquisition processor and a plurality of sampling chips. The acquisition processor is connected to the plurality of sampling chips at the same time. The sampling chips are power chips for current and voltage sampling.

[0006] Preferably, the outputs of the sampling chips include three-phase voltage, three-phase current, active power, reactive power, frequency, phase angle, and harmonic data.

[0007] Preferably, the data processing module is connected to the acquisition processor through a USB data cable. The data processing module is at least provided with an Ethernet interface, an optical interface, a serial port, a USB interface, a B-code time synchronization interface, and a wireless interface. The interfaces are used for communicating with the dispatching system and the local controller.

[0008] Preferably, the data processing module is also provided with a longitudinal encryption module. The longitudinal encryption module is used to encrypt the processed and analyzed data. The dispatching system is provided with a decryption module, and the decryption module is used to decrypt the encrypted data.

[0009] A control method for a new energy stable coordination controller includes the following steps: Step 1, the signal acquisition module acquires the real-time status data of new energy power generation and the real-time status data of the distribution network system; Step 2, the data processing module processes and analyzes the real-time status data, generates analysis data adapted to the dispatching system, and sends it to the dispatching system; Step 3, after receiving the analysis data, the dispatching system generates a dispatching instruction according to the analysis data and sends it to the data processing module; Step 4, the data processing module sends the dispatching instruction to the local controller for execution.

[0010] Preferably, in the above Step 2, when the data processing module processes and analyzes the real-time status data, specifically: it performs compliance verification on the real-time status data of new energy power generation to determine whether it meets the constraint conditions including the node voltage offset threshold, harmonic content standard, and three-phase unbalance limit; Calculate the active power and reactive power adjustment margins of new energy power generation according to the real-time status data of new energy power generation, and generate local control parameters for AVC, AGC, and primary frequency modulation.

[0011] Preferably, in the above Step 3, when the dispatching system generates a dispatching instruction according to the analysis data, the dispatching system also acquires the grid operation parameters, and generates a dispatching instruction in combination with the analysis data and the operation parameters. The grid operation parameters include: The real-time power flow distribution of the grid, node voltage fluctuation data, and harmonic monitoring results; The reverse peak shaving characteristics of the new energy power generation system and the management index of the line loss in the substation area.

[0012] Preferably, in the above Step 4, a timing logic check is also performed on the dispatching instruction to ensure coordination with the action time limit of the distribution network relay protection device.

[0013] Preferably, after the in-situ controller executes the scheduling instruction, the execution result is also fed back to the data processing module. The data processing module performs closed-loop verification on the feedback result. If abnormal voltage, frequency, or excessive harmonics are detected, the switching threshold of the reactive power compensation device is dynamically adjusted or the fluctuation range of new energy output is restricted.

[0014] The beneficial effects of the present invention are as follows: The present invention accurately captures the transient changes in new energy power generation, solves the problem of lagging state evaluation caused by traditional low-speed sampling, and provides data support with millisecond-level accuracy for real-time regulation.

[0015] The present invention real-time verifies whether new energy power generation meets the grid security constraints, automatically triggers power limitation or reactive power compensation, and avoids equipment failures or grid disconnection risks caused by voltage over-limit and excessive harmonics.

[0016] Through the full-process technological innovation of high-speed acquisition, intelligent verification, secure communication, and closed-loop control, this solution systematically solves the defects of the existing technology in new energy access management and control, realizes the observability, measurability, controllability, and adjustability of distributed power sources and distribution networks, and provides key technical support for the safe, stable, and economic operation of the power grid under the scenario of high-penetration new energy grid connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is the circuit schematic diagram of the new energy stable coordination controller of the present invention connected to the power grid; Figure 2 is the circuit schematic diagram of the signal acquisition module and the data processing module of the present invention; Figure 3 is a flowchart of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be more complete and will fully convey the concept of the example embodiments to those skilled in the art.

[0019] In addition, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the embodiments of this application. However, those skilled in the art will realize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, well-known methods, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of this application.

[0020] The block diagrams shown in the drawings are only functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0021] The flowcharts shown in the drawings are only exemplary illustrations, not necessarily including all contents and operations / steps, nor necessarily executed in the described order. For example, some operations / steps can be decomposed, while some operations / steps can be combined or partially combined, so the actual execution order may change according to the actual situation.

[0022] Embodiment: As Figure 1 、 Figure 2 shown, a new energy stable coordination controller includes: A signal acquisition module for acquiring real-time status data of new energy power generation and real-time status data of the distribution network system; A data processing module for receiving the data acquired by the signal acquisition module, processing and analyzing it, then sending the processed and analyzed data to the dispatching system, receiving the dispatching instructions matched according to the processed and analyzed data by the dispatching system, and then decomposing and issuing the dispatching instructions to the local controller for execution.

[0023] The signal acquisition module includes an acquisition processor and several sampling chips. The acquisition processor is connected to several sampling chips at the same time. The sampling chips are power chips for current and voltage sampling. The outputs of the sampling chips include three-phase voltage, three-phase current, active power, reactive power, frequency, phase angle and harmonic data. The sampling chips achieve 12-channel sampling, and the sampling frequency is above 14.4 kHz.

[0024] The data processing module is connected to the acquisition processor through a USB data cable. The data processing module is provided with 4 Ethernet interfaces, 2 optical interfaces, 2 serial ports, 1 USB interface, a B-code time synchronization interface and a wireless interface. The interfaces are used for communicating with the dispatching system and the local controller.

[0025] The data processing module is also provided with a longitudinal encryption module for encrypting the processed and analyzed data. The dispatching system is provided with a decryption module for decrypting the encrypted data.

[0026] In the software layer architecture of the new energy stable coordination controller, it includes modules such as driver programs, system kernels, communication management, and data processing. The implementation adopts component technology, and business functions such as data acquisition, forwarding, caching, encryption, and processing are completed by a series of reusable independent components working together. These components can be configured and run independently. If there are problems, it will not affect other components and can be reused. Component technology can effectively improve the stability of the business system of the new energy stable coordination controller and enhance the efficiency of engineering deployment of intelligent terminals.

[0027] A control method for a new energy stable coordination controller, as Figure 3 shown, includes the following steps: Step 1, the signal acquisition module acquires the real-time status data of new energy power generation and the real-time status data of the distribution network system; Step 2, the data processing module processes and analyzes the real-time status data, generates analysis data adapted to the dispatching system, and sends it to the dispatching system; Step 3, after receiving the analysis data, the dispatching system generates a dispatching instruction according to the analysis data and sends it to the data processing module; Step 4, the data processing module sends the dispatching instruction to the local controller for execution.

[0028] In the above-mentioned Step 2, when the data processing module processes and analyzes the real-time status data, specifically: Perform compliance verification on the real-time status data of new energy power generation, and judge whether it meets the constraint conditions including the node voltage deviation threshold, harmonic content standard, and three-phase unbalance limit; Calculate the active power and reactive power regulation margins of new energy power generation according to the real-time status data of new energy power generation, and generate local control parameters for AVC, AGC, and primary frequency modulation.

[0029] Specifically, the compliance verification includes: 1. Node voltage deviation threshold verification Data acquisition: The three-phase voltage values at the grid connection point of a distributed photovoltaic power station collected by the signal acquisition module at a certain moment are UA = 235V, UB = 232V, and UC = 233V.

[0030] Set the standard: According to relevant power standards and distribution network operation requirements, set the node voltage deviation threshold to ±7% of the rated voltage UN = 230V, that is, the voltage range is between 213V - 246V.

[0031] Verification process: Compare the collected three-phase voltage values with the set voltage range, and it is found that UA, UB, and UC are all within the range of 213V - 246V. Therefore, the voltage at the grid connection point of the distributed photovoltaic power station at this moment meets the node voltage deviation threshold constraint condition.

[0032] 2. Obtaining harmonic content standard verification data: Collect the harmonic contents of each order of the output current of the distributed photovoltaic power station. For example, the 3rd harmonic current content I3 = 1.2 A, the 5th harmonic current content I5 = 0.8 A, the 7th harmonic current content I7 = 0.6 A, etc.

[0033] Setting standards: According to relevant power quality standards, it is stipulated that the 3rd harmonic current ratio shall not exceed 5%, the 5th harmonic current ratio shall not exceed 4%, and the 7th harmonic current ratio shall not exceed 3%. Assume that the fundamental wave current I1 of this photovoltaic power station is 20 A.

[0034] Verification process: Calculate the harmonic current ratios of each order respectively. The 3rd harmonic current ratio HR3 = 6%, the 5th harmonic current ratio HR5 = 4%, and the 7th harmonic current ratio HR7 = 3%. The 3rd harmonic current ratio exceeds the standard and does not meet the harmonic content standard constraint conditions.

[0035] 3. Obtaining three-phase unbalance degree limit verification data: The three-phase current values output by the wind farm are collected as I A = 100 A, I B = 95 A, I C = 102 A.

[0036] Setting standards: According to the operation requirements of the power system, the three-phase unbalance degree limit is set to 2%.

[0037] Verification process: First, calculate the average value of the three-phase current Iavg = 3IA + IB + IC = 3100 + 95 + 102 ≈ 99 A. Then, calculate the three-phase current unbalance degree ∈I = IavgImax - Imin × 100% = 99102 - 95 × 100% ≈ 7.07%, which exceeds the limit of 2% and does not meet the three-phase unbalance degree limit constraint conditions.

[0038] Calculating active power, reactive power regulation margin and generating control parameters 1. Calculating active power and reactive power regulation margin Data acquisition: It is known that at a certain moment, the actual active power output Pactual of the distributed photovoltaic power station is 500 kW, its maximum active power output capacity Pmax is 600 kW, and its minimum active power output capacity Pmin is 100 kW; the actual reactive power output Qactual is 100 kVar, the maximum reactive power output capacity Qmax is 150 kVar, and the minimum reactive power output capacity Qmin is -50 kVar.

[0039] Calculation process: Active power regulation margin: The upward regulation margin ΔPup = Pmax - Pactual = 600 - 500 = 100 kW, and the downward regulation margin ΔPdown = Pactual - Pmin = 500 - 100 = 400 kW.

[0040] Reactive power regulation margin: The upward regulation margin ΔQup = Qmax - Qactual = 150 - 100 = 50 kVar, and the downward regulation margin ΔQdown = Qactual - Qmin = 100 - (-50) = 150 kVar.

[0041] 2. Generate local control parameters for AVC, AGC, and primary frequency modulation AVC (Automatic Voltage Control) parameter generation: Based on the reactive power regulation margin calculated above and the voltage deviation situation (such as the problems found in the previous voltage offset check), if the grid connection point voltage is low and there is an upward regulation margin for reactive power, then generate control parameters to increase the reactive power output. For example, set to increase the reactive power output by 20 kVar to raise the grid connection point voltage.

[0042] AGC (Automatic Generation Control) parameter generation: Considering the active power regulation margin and the grid load demand, if the grid load increases and there is an upward regulation margin for active power, then generate control parameters to increase the active power output. For example, set to increase the active power output by 30 kW.

[0043] Primary frequency modulation local control parameter generation: When it is detected that the grid frequency changes, generate primary frequency modulation control parameters based on the frequency deviation and the active power regulation margin. Assume that the grid frequency drops by 0.1 Hz, and according to the pre-set frequency modulation coefficient and the active power regulation margin, calculate that the active power output to be increased is 20 kW, which is used as the control parameter for primary frequency modulation.

[0044] In step 3 described above, when the dispatching system generates a dispatching instruction based on the analysis data, the dispatching system also acquires grid operation parameters, and generates a dispatching instruction by combining the analysis data and the operation parameters. The grid operation parameters include: Grid real-time power flow distribution, node voltage fluctuation data, and harmonic monitoring results; The reverse peak shaving characteristics of the new energy power generation system and the distribution network line loss management index of the substation area.

[0045] Specifically, a 1 MW distributed photovoltaic power station is connected to the distribution network of a certain substation area. The reverse peak shaving characteristics are: high output during the day and low load, low output at night and high load. A 500 kWh energy storage system is configured, and the target of the distribution network line loss rate of the substation area is ≤3%. The current real-time operation parameters are: Active power regulation margin of PV power station: 200 kW upward, 500 kW downward; Reactive power regulation margin: 150 kVar upward, 200 kVar downward.

[0046] Compliance check: Node voltage deviation +5% (close to the upper limit of 7%), 3rd harmonic current content rate 5.5% (exceeding the standard), three-phase unbalance degree 3% (exceeding the standard).

[0047] Real-time power flow: Load rate of the 10 kV incoming line in the substation area is 85% (close to the overload threshold of 90%), voltage at node A is 245 V (rated 230 V, deviation +6.5%), total harmonic distortion rate of harmonic voltage at node B THD = 4.2% (standard ≤ 3%).

[0048] Reverse peak shaving characteristics: Currently at 14:00, PV output is 800 kW, load in the substation area is only 300 kW, state of charge (SOC) of energy storage = 60%.

[0049] Line loss in the substation area: Current line loss rate is 4.5% (higher than the target of 3%).

[0050] Process of generating dispatching instructions 1. Instructions based on real-time power flow and voltage fluctuation Problem identification: High load rate of the incoming line (85%) + voltage at node A approaching the limit (+6.5%), it is necessary to prevent overload and voltage exceeding the standard.

[0051] Instruction generation: Active power regulation: Require the PV power station to reduce the active output from 800 kW to 600 kW (downward adjustment of 200 kW, releasing line capacity), and at the same time trigger the energy storage system to charge at a power of 200 kW (consuming excess active power and reducing line power flow).

[0052] Reactive power regulation: For the high voltage at node A, instruct the PV power station to increase the capacitive reactive output by 100 kVar (utilizing the upward regulation margin of 150 kVar), enhancing the reactive power compensation ability of the line and suppressing the further rise of voltage.

[0053] 2. Instructions based on harmonic monitoring results Problem identification: Harmonic THD at node B = 4.2% (exceeding the standard), mainly caused by the 3rd harmonic generated by the PV inverter.

[0054] Instruction generation: Start the harmonic filter built in the PV power station, and require it to control the 3rd harmonic current content rate within 5% (combining the compliance check threshold in claim 6); If the filtering capacity of a single device is insufficient, the dispatching system synchronously sends instructions to adjacent energy storage converters to cooperate in injecting reverse harmonic current to offset harmonic pollution.

[0055] 3. Instructions Based on Reverse Peak-Shaving Characteristics and Substation Area Line Loss Problem Identification: Photovoltaic reverse peak-shaving causes power backfeeding in the substation area during the day (photovoltaic output 800 kW > load 300 kW), resulting in an increase in line loss (4.5% > 3%).

[0056] Instruction Generation: Utilize the capacity of the energy storage with SOC = 60% to continuously charge at a power of 200 kW during the peak photovoltaic period from 14:00 to 17:00 (consuming excess electric energy), and discharge at a power of 150 kW during the peak load period from 19:00 to 22:00 to balance the supply and demand in the substation area and reduce the line loss caused by backfeeding power.

[0057] According to the substation area line loss management index, calculate that the current power factor is 0.85 (lagging), and instruct the photovoltaic power station to increase the power factor to 0.95 (leading) to reduce line loss through reactive power compensation.

[0058] After the photovoltaic output decreases, the incoming line load rate drops to 65%, and the voltage at node A drops back to 238 V (offset +3.5%), eliminating the risks of overload and voltage overlimit; The content of the 3rd harmonic current drops to 4.8%, and the harmonic THD at node B drops to 2.8%, meeting the national standard requirements; The energy storage charge and discharge balance the power in the substation area, the backfeeding power drops from 500 kW to 100 kW, and the substation area line loss rate drops to 2.8%, achieving the management goal.

[0059] In step 4 described above, the timing logic of the dispatching instruction is also verified to ensure coordination with the action time limit of the distribution network relay protection device.

[0060] After the local controller executes the dispatching instruction, the execution result is also fed back to the data processing module. The data processing module performs closed-loop verification on the feedback result. If abnormal voltage, frequency, or harmonic overstandard is detected, the switching threshold of the reactive power compensation device is dynamically adjusted or the fluctuation range of new energy output is limited.

[0061] After considering the specification and the disclosed embodiments herein, those skilled in the art will readily conceive of other embodiments of the present application. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include the common general knowledge or conventional technical means in the technical field not disclosed in the present application.

[0062] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A new energy stable coordination controller, characterized in that, Including: A signal acquisition module, which is used to acquire the real-time status data of new energy power generation and the real-time status data of the distribution network system; A data processing module, which is used to receive the data acquired by the signal acquisition module, process and analyze it, then send the processed and analyzed data to the dispatching system, receive the dispatching instructions matched according to the processed and analyzed data by the dispatching system, and then decompose and issue the dispatching instructions to the local controller for execution; The signal acquisition module includes an acquisition processor and several sampling chips. The acquisition processor is connected to several sampling chips at the same time. The sampling chips are power chips and are used for current and voltage sampling.

2. The new energy stable coordination controller according to claim 1, wherein, The outputs of the sampling chips include three-phase voltage, three-phase current, active power, reactive power, frequency, phase angle and harmonic data.

3. The new energy stable coordination controller according to claim 2, characterized in that, The data processing module is connected to the acquisition processor through a USB data cable. The data processing module is at least provided with an Ethernet interface, an optical interface, a serial port, a USB interface, a B-code time synchronization interface and a wireless interface. The interfaces are used for communicating with the dispatching system and the local controller.

4. A new energy stable coordination controller according to claim 1, characterized in that, The data processing module is also provided with a longitudinal encryption module, which is used to encrypt the processed and analyzed data. The dispatching system is provided with a decryption module, which is used to decrypt the encrypted data.

5. A control method for a new energy stable coordination controller, characterized in that Including the following steps: Step 1, the signal acquisition module acquires the real-time status data of new energy power generation and the real-time status data of the distribution network system; Step 2, the data processing module processes and analyzes the real-time status data, generates analysis data adapted to the dispatching system and sends it to the dispatching system; Step 3, after receiving the analysis data, the dispatching system generates dispatching instructions according to the analysis data and sends them to the data processing module; Step 4, the data processing module sends the dispatching instructions to the local controller for execution.

6. The control method of a new energy stable coordination controller according to claim 5, characterized in that, In the said Step 2, when the data processing module processes and analyzes the real-time status data, specifically: Perform compliance verification on the real-time status data of new energy power generation, and judge whether it meets the constraint conditions including the node voltage deviation threshold, harmonic content standard, and three-phase unbalance limit; Calculate the active power and reactive power adjustment margins of new energy power generation according to the real-time status data of new energy power generation, and generate local control parameters for AVC, AGC and primary frequency modulation.

7. The control method of a new energy stable coordination controller according to claim 5, characterized in that, In the said Step 3, when the dispatching system generates dispatching instructions according to the analysis data, the dispatching system also acquires the grid operation parameters, and generates dispatching instructions by combining the analysis data and the operation parameters. The grid operation parameters include: The real-time power flow distribution of the grid, node voltage fluctuation data and harmonic monitoring results; The reverse peak shaving characteristics of the new energy power generation system and the management index of the line loss of the distribution transformer area.

8. The control method of a new energy stable coordination controller according to claim 5, characterized in that, In the said Step 4, perform timing logic verification on the dispatching instructions to ensure coordination with the action time limit of the distribution network relay protection device.

9. The control method of a new energy stable coordination controller according to claim 5, characterized in that, After the local controller executes the dispatching instructions, the execution result is also fed back to the data processing module. The data processing module performs closed-loop verification on the feedback result. If voltage, frequency anomalies or harmonic over-standard are detected, the switching threshold of the reactive power compensation device is dynamically adjusted or the fluctuation range of new energy output is limited.

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