A reactive power compensation control method for new energy power plants based on distributed control

Abstract

This invention discloses a reactive power compensation control method for new energy power plants based on distributed control, belonging to the field of automatic voltage control technology. The method configures an independent communication node on each generating unit within the power plant and sets up a contact node connected to a distributed network. The method includes: distributed data acquisition and interaction, distributed system impedance calculation, distributed reactive power demand determination, selection of compensation equipment and transmission of regulation information, allocation of regulation, and execution of hierarchical reactive power regulation. The contact node calculates the system impedance and total reactive power regulation based on the collected grid connection point data. Each communication node relays the statistics of the overall regulation capacity of the power plant and allocates reactive power according to the principle of proportionality or full capacity, prioritizing regulation by the generating units, and supplementing with static reactive power compensation equipment when insufficient. This invention first utilizes the reactive power regulation capacity of the generating units, only activating SVG equipment when the overall regulation capacity is insufficient, significantly reducing the SVG commissioning time and operating costs, resulting in superior economic efficiency.

Description

Technical Field

[0001] This invention relates to the field of voltage automatic control technology, specifically to a reactive power compensation control method for new energy power plants based on distributed control. Background Technology

[0002] Traditional renewable energy power plants typically employ centralized automatic voltage control (AVC) systems for reactive power and voltage control. A central substation collects operational data from the entire plant, calculates reactive power demand, and issues adjustment commands one by one. This architecture is highly dependent on the central node and centralized communication links. If the central node fails or communication is interrupted, reactive power control across the entire plant will fail, resulting in low system reliability. Furthermore, traditional solutions rely excessively on static var compensators (SVG) for reactive power regulation, leading to high investment and operating costs. While wind turbines and photovoltaic inverters possess some reactive power regulation capabilities, centralized control suffers from data transmission delays and inaccurate regulation capacity statistics, resulting in underutilization of the reactive power potential of power generation units and an excessively high unnecessary SVG equipment utilization rate. Summary of the Invention

[0003] The technical problem this invention aims to solve is to provide a reactive power compensation control method for new energy power plants based on distributed control. This method enables autonomous coordination of power generation units, distributed computing, and hierarchical regulation, significantly improving system reliability, control accuracy, and economy.

[0004] The technical solution adopted by this invention to solve its technical problem is a reactive power compensation control method for new energy power plants based on distributed control. Each power generation unit in the power plant is equipped with an independent communication node, and these communication nodes form a distributed network without a central node through point-to-point relay communication. A communication node is set up in the power plant to communicate with the distributed network. This communication node is used to receive the real-time voltage value of the grid connection point, the reactive power injected into the grid, and the target voltage value of the grid connection point bus issued by the automatic voltage control master station, and is also connected to the static reactive power compensation equipment. The method includes the following steps:

[0005] S1: Distributed data acquisition and interaction, each power generation unit collects its own operating data in real time, and realizes distributed data sharing across the entire site through relay communication;

[0006] S2: Distributed system impedance calculation, based on the real-time voltage values ​​U0 and U1 of the grid connection point at two consecutive times t0 and t1 collected by the interconnecting node, and the reactive power Q0 and Q1 injected into the grid, the system impedance X is calculated using the following formula: ;

[0007] S3: Distributed reactive power demand determination, with interconnection nodes based on system impedance X and target voltage. and real-time voltage value at the grid connection point and reactive power Calculate the target reactive power and total reactive power regulation :

[0008] ,

[0009] ;

[0010] S4: Distributed compensation equipment screening and regulation information transmission. Starting from the contact node, the total reactive power regulation amount is sent to the adjacent communication nodes in sequence. Each power generation unit calculates its own reactive power regulation capacity component and transmits it to the communication node. The components are then summarized into the total upward and downward regulation space of the entire field through relay communication, forming a statistical table of the total regulation capacity of the entire field.

[0011] S5: Distributed compensation equipment regulation allocation. The last communication node determines whether the overall regulation space meets the total reactive power regulation requirement. Based on the determination result, the reactive power allocation of each power generation unit is calculated according to the principle of proportional allocation or full allocation, forming a regulation allocation table for each power generation unit in the whole field, and is transmitted back to the contact node through relay communication. If the regulation space is insufficient, the contact node calculates the compensation difference of the static reactive power compensation equipment.

[0012] S6: Hierarchical reactive power regulation is implemented, with each power generation unit prioritizing reactive power regulation according to its allocated amount. If the regulation capacity is insufficient, the liaison node will then notify the static reactive power compensation equipment to supplement the regulation according to the compensation difference.

[0013] Furthermore, in S4, each power generation unit calculates its own reactive power regulation capacity component in the following way:

[0014] Reactive power increase spatial component: ;

[0015] Reactive power reduction spatial component: ;

[0016] in, Let be the upper limit of reactive power compensation for the i-th power generation unit. Let be the real-time reactive power compensation amount of the i-th power generation unit. This is the lower limit of reactive power compensation for the i-th power generation unit.

[0017] Furthermore, in S4, the information is transmitted in tabular form. The total field regulation capacity statistics table includes the following fields: node name, node number, total reactive power regulation, reactive power upward adjustment space component, reactive power downward adjustment space component, total field upward adjustment space, total field downward adjustment space, and whether all nodes are included. The contact node fills in the first row of the table, and subsequent communication nodes fill in their own information and the accumulated total field upward adjustment space and total field downward adjustment space in the next row.

[0018] Furthermore, in S5, the method for determining whether the overall field adjustment space meets the total reactive power adjustment requirement is as follows:

[0019] like ,and If yes, then the requirement is met; otherwise, the requirement is not met.

[0020] like ,and If it meets the requirement, then the requirement is met; otherwise, the requirement is not met.

[0021] Furthermore, in step S5, when the demand is met, the reactive power regulation allocation for each power generation unit is calculated according to the principle of proportional allocation:

[0022] like ,but ;

[0023] like ,but ;

[0024] in, The sum of the reactive power upward adjustment space components of each power generation unit. This is the sum of the reactive power reduction spatial components of each power generation unit. Let i be the reactive power regulation allocation for the i-th generating unit. hour, To increase the quantity, hour, To reduce the amount, the adjustment amount allocation table of each power generation unit in the whole field is transmitted in reverse from the last communication node, and the reactive power allocation of the previous communication node is calculated in turn until the connection node.

[0025] Furthermore, in step S5, when the demand is not met, the reactive power allocation for each communication node is calculated according to the full allocation principle:

[0026] like ,but ;

[0027] like ,but ;

[0028] in, Let i be the reactive power regulation allocation for the i-th generating unit. hour, To increase the quantity, hour, To reduce the amount of reactive power, the reactive power allocation table for all power generation units in the entire field is transmitted in reverse from the last communication node, calculating the reactive power allocation of the previous communication node sequentially until the tie node; the tie node calculates the compensation difference of the static reactive power compensation equipment. :

[0029] like ,but ;

[0030] like ,but ;

[0031] hour, To increase the quantity, hour The adjustment is downward.

[0032] Furthermore, in S5, the regulation allocation table for all power generation units in the field includes the following fields: node name, node number, total reactive power regulation, reactive power allocation for this node, and whether all nodes have been included.

[0033] Furthermore, the entire control process is executed every 15 minutes.

[0034] Furthermore, the power generation unit includes a wind turbine generator and a photovoltaic inverter.

[0035] The beneficial effects of this invention are as follows: It adopts a distributed network architecture without a central node, ensuring that the failure of any one or several communication nodes will not lead to a complete control paralysis, thus completely avoiding the risk of single-point failure and significantly improving system reliability; it uses point-to-point relay communication, forwarding table information containing only core data one by one, resulting in low communication load and strong anti-interference capability, making it suitable for new energy power plants in complex terrains such as mountainous areas and Gobi deserts; it prioritizes the reactive power regulation capability of the power generation units, only activating SVG equipment when the overall regulation capability is insufficient, significantly reducing SVG commissioning time and operating costs, resulting in superior economic efficiency; it has automatic fault relay compensation capability, allowing other nodes to complete data aggregation and distribution even when some nodes exit, ensuring uninterrupted reactive power regulation and stronger system dynamic stability. Attached Figure Description

[0036] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0037] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0038] Example 1

[0039] The power station configuration includes 40 2MW wind turbine generators (each with a reactive power regulation upper limit of 80kvar, lower limit of -40kvar, and real-time reactive power of 50kvar), 80 1MW photovoltaic inverters (each with a reactive power regulation upper limit of 40kvar, lower limit of -15kvar, and real-time reactive power of 25kvar), and one ±15Mvar static var compensator (SVG). The power station has one communication node, and each generator unit is equipped with an independent communication node, forming a distributed network without a central node through point-to-point relay communication. The communication node is connected to the distributed network and also to the SVG. The entire control process is executed every 15 minutes. See [link / reference]. Figure 1 Includes the following steps:

[0040] S1: Distributed Data Acquisition and Interaction

[0041] Each wind turbine generator and photovoltaic inverter's communication node collects real-time operational data such as unit terminal voltage, real-time reactive power, and reactive power regulation upper and lower limits. After collection, each node distributes and shares the core data across the entire site via hop-by-hop relay communication, and verifies the data's validity to reduce communication load. The communication node also receives the target bus voltage value at the grid connection point from the dispatch AVC master station. Real-time voltage at the grid connection point and reactive power injected into the grid.

[0042] S2: Distributed System Impedance Calculation

[0043] The interconnection node serves as the starting calculation node, collecting the real-time voltage values ​​U0 and U1 at two consecutive times t0 and t1 at the grid connection point, as well as the reactive power Q0 and Q1 injected into the grid from the power station. In this example:

[0044] At time t0: U0 = 34.4 kV, Q0 = 6.5 Mvar;

[0045] At time t1: U1 = 34.6 kV, Q1 = 7.2 Mvar.

[0046] Calculate the system impedance X using the formula:

[0047]

[0048] S3: Distributed Reactive Power Demand Determination

[0049] The connection node uses the calculated X and target voltage In this example Given a voltage of 35.0 kV and real-time voltage U1 and reactive power Q1 at time t1, calculate the target reactive power using the following formula. and total reactive power regulation :

[0050]

[0051]

[0052] Take 0.64Mvar, because If the value is >0, it is determined that the reactive power needs to be increased by 0.64 Mvar across the entire field.

[0053] S4: Distributed compensation equipment screening and adjustment quantity information transmission

[0054] The contact node sends to the adjacent communication node =0.64Mvar, and is transmitted sequentially via relay communication. Each communication node receiving the information calculates the reactive power regulation capacity component of its respective power generation unit:

[0055] Single wind turbine generator set: =80-50=30kvar; =50-(-40)=90kvar.

[0056] Single photovoltaic inverter: =40-25=15kvar; =25-(-15)=40kvar.

[0057] Each node fills its own component into the overall adjustment capacity statistics table (the table includes: node name, number, Q_total shortage, upward adjustment space component, downward adjustment space component, cumulative total upward adjustment space, cumulative total downward adjustment space, and whether all nodes are included). The contact node fills in the first row, and subsequent communication nodes add a row in turn, and the total upward adjustment space and total downward adjustment space of the entire field are accumulated.

[0058] In this example, the total upregulation space for 40 wind turbine generators is 40 × 30 kvar = 1.2 Mvar; the total upregulation space for 80 photovoltaic inverters is 80 × 15 kvar = 1.2 Mvar; and the total upregulation space for the entire site is 2.4 Mvar. After the last communication node completes the accumulation, the "Have all nodes been included?" option is marked as "Yes".

[0059] S5: Distribution of Adjustment Quantity for Distributed Compensation Equipment

[0060] The last communication node determines whether the overall adjustment space meets the requirements:

[0061] because ,and =2.4-0.64=1.76Mvar≥0, which meets the requirements.

[0062] Calculate the reactive power allocation for each power generation unit according to the principle of proportional allocation:

[0063] The allocation factor for a single wind turbine generator is 30 kvar / 2400 kvar = 0.0125, and the allocation amount per unit is 0.64 Mvar × 0.0125 = 8 kvar.

[0064] The allocation factor for a single photovoltaic inverter is 15kvar / 2400kvar = 0.00625, and the allocation amount per unit is 0.64Mvar × 0.00625 = 4kvar.

[0065] After the last communication node calculates its own allocation, it generates a table of regulation allocation for all power generation units in the field (including: node name, number, Q_total deficit, reactive power allocation for this node, and whether the node has been fully included), and then relays the table in reverse (from the last node to the connecting node). Upon receiving the table, the previous node calculates its own allocation and supplements the table information until the connecting node completes the process.

[0066] The connection node calculates the SVG compensation difference: because =2.4Mvar≥ =0.64Mvar, =-1.76Mvar (negative value indicates no SVG compensation is needed), the actual SVG difference is 0Mvar, and no SVG needs to be put into operation for this control.

[0067] S6: Graded reactive power regulation execution

[0068] Each wind turbine generator and photovoltaic inverter autonomously adjusts its reactive power according to the reactive power allocation of its node in the overall power generation unit adjustment allocation table:

[0069] The reactive power of a single wind turbine has been increased from 50 kvar to 58 kvar.

[0070] The reactive power of a single photovoltaic unit has been increased from 25 kvar to 29 kvar.

[0071] After adjustment, the interconnection node monitored the grid connection point voltage in real time: the voltage steadily increased from 34.6kV before adjustment to approximately 35.02kV, reaching the target voltage requirement of 35.0kV issued by the dispatch center. Due to the sufficient adjustment capacity of the generating unit, the SVG was not put into operation.

[0072] Example 2

[0073] If the dispatch sends the target voltage =35.6kV, other conditions remain unchanged, calculated using S2 and S3. =2.6Mvar > Total upward adjustment space of 2.4Mvar. Therefore, in S5, it is determined that the demand is not met, and the full allocation principle is executed:

[0074] Distribution capacity of each fan = its own =30kvar, total compensation of 1.2Mvar for 40 wind turbines;

[0075] Each photovoltaic allocation = its own =15kvar, total compensation of 1.2Mvar for 80 photovoltaic units;

[0076] The contact node calculates the SVG compensation difference as 2.6 - 2.4 = 0.2 Mvar and notifies the SVG to increase by 0.2 Mvar.

[0077] In S6, the generator unit first adjusts to full capacity, the SVG supplements the remaining deficit, and the grid connection point voltage eventually stabilizes at 35.6kV.

[0078] The above process fully verifies the feasibility of the method of the present invention under normal and extreme operating conditions, and realizes distributed collaboration, on-demand hierarchical adjustment and SVG minimization of deployment.

[0079] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A reactive power compensation control method for new energy power plants based on distributed control, characterized in that, Each power generation unit in the power station is equipped with an independent communication node. The communication nodes form a distributed network without a central node through point-to-point relay communication. A contact node is set up in the power station to communicate with the distributed network. The contact node is used to receive the real-time voltage value of the grid connection point, the reactive power injected into the grid, and the target voltage value of the grid connection point bus issued by the automatic voltage control station. It is also connected to the static reactive power compensation equipment. Includes the following steps: S1: Distributed data acquisition and interaction, each power generation unit collects its own operating data in real time, and realizes distributed data sharing across the entire site through relay communication; S2: Distributed system impedance calculation, based on the real-time voltage values ​​U0 and U1 of the grid connection point at two consecutive times t0 and t1 collected by the interconnecting node, and the reactive power Q0 and Q1 injected into the grid, the system impedance X is calculated using the following formula: ; S3: Distributed reactive power demand determination, with interconnection nodes based on system impedance X and target voltage. and real-time voltage value at the grid connection point and reactive power Calculate the target reactive power and total reactive power regulation : ， ； S4: Distributed compensation equipment screening and regulation information transmission. Starting from the contact node, the total reactive power regulation amount is sent to the adjacent communication nodes in sequence. Each power generation unit calculates its own reactive power regulation capacity component and transmits it to the communication node. The components are then summarized into the total upward and downward regulation space of the entire field through relay communication, forming a statistical table of the total regulation capacity of the entire field. S5: Distributed compensation equipment regulation allocation. The last communication node determines whether the overall regulation space meets the total reactive power regulation requirement. Based on the determination result, it calculates the reactive power allocation for each power generation unit according to the principle of proportional allocation or full allocation, forming a regulation allocation table for all power generation units in the entire field. This table is then transmitted back to the contact node via relay communication. If the regulation space is insufficient, the contact node calculates the compensation difference for the static reactive power compensation equipment. When the requirement is met, the reactive power regulation allocation for each power generation unit is calculated according to the principle of proportional allocation. like ,but ; like ,but ; in, The sum of the reactive power upward adjustment space components of each power generation unit. This is the sum of the reactive power reduction spatial components of each power generation unit. The reactive power regulation allocation is set for the i-th power generation unit, and the regulation allocation table of all power generation units in the field is transmitted in reverse from the last communication node. The reactive power allocation of the previous communication node is calculated in turn until the contact node. When the demand is not met, the reactive power allocation for each communication node is calculated according to the principle of full allocation: like ,but ; like ,but ; Starting from the last communication node, the regulation allocation table for all power generation units in the entire field is transmitted in reverse order, calculating the reactive power allocation of the previous communication node sequentially until the tie node; the tie node calculates the compensation difference of the static reactive power compensation equipment. : like ,but ; like ,but ; S6: Hierarchical reactive power regulation is implemented, with each power generation unit prioritizing reactive power regulation according to its allocated amount. If the regulation capacity is insufficient, the liaison node will then notify the static reactive power compensation equipment to supplement the regulation according to the compensation difference.

2. The reactive power compensation control method for new energy power plants based on distributed control according to claim 1, characterized in that, In S4, each power generation unit calculates its own reactive power regulation capacity component in the following way: Reactive power adjustment spatial component: ; Reactive power reduction spatial component: ; in, Let be the upper limit of reactive power compensation for the i-th power generation unit. Let be the real-time reactive power compensation amount of the i-th power generation unit. This is the lower limit of reactive power compensation for the i-th power generation unit.

3. The reactive power compensation control method for new energy power plants based on distributed control according to claim 1, characterized in that, In step S4, information is transmitted in tabular form. The total field regulation capacity statistics table includes the following fields: node name, node number, total reactive power regulation, reactive power upward adjustment space component, reactive power downward adjustment space component, total field upward adjustment space, total field downward adjustment space, and whether all nodes are included. The contact node fills in the first row of the table, and subsequent communication nodes fill in their own information and the accumulated total field upward adjustment space and total field downward adjustment space in the next row.

4. The reactive power compensation control method for new energy power plants based on distributed control according to claim 2, characterized in that, In S5, the method for determining whether the overall field adjustment space meets the total reactive power adjustment requirement is as follows: like ,and If yes, then the requirement is met; otherwise, the requirement is not met. like ,and If it meets the requirement, then the requirement is met; otherwise, the requirement is not met.

5. The reactive power compensation control method for new energy power plants based on distributed control according to claim 1, characterized in that, In S5, the regulation allocation table for all power generation units in the field includes the following fields: node name, node number, total reactive power regulation, reactive power allocation for this node, and whether all nodes are included.

6. The reactive power compensation control method for new energy power plants based on distributed control according to claim 1, characterized in that, The entire control process is executed every 15 minutes.

7. The reactive power compensation control method for new energy power plants based on distributed control according to claim 1, characterized in that, The power generation unit includes a wind turbine generator and a photovoltaic inverter.

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