Method and system for realizing rotational inertia unified control of wide-area distributed new energy station

Abstract

The invention discloses a method and system for realizing rotational inertia unified control of wide-area distributed new energy stations, and the method comprises the steps: employing an inertia cooperative control main station to calculate the minimum value of rotational inertia required by a regional power grid according to global measurement information, the rotational inertia of a conventional unit, and the virtual rotational inertia of the new energy stations which do not participate in cooperative control; determining a virtual rotational inertia adjusting quantity required by the regional power grid in real time; based on the real-time frequency of the highest-voltage-grade bus, determining the active power regulation quantity required by the regional power grid in real time by using the virtual rotational inertia regulation quantity, and distributing the active power regulation quantity to each new energy station participating in cooperative control; an instruction formed by the active power adjusting quantity distributed to each new energy station and the time mark corresponding to the real-time frequency of the bus with the highest voltage grade is sent to each inertia cooperative control substation; and the substation determines the corrected active power regulation quantity by using the instructions received this time and last time and the time mark of the instruction received this time so as to control the output power of the converter and cooperatively control the rotational inertia of the regional power grid.

Description

Technical Field

[0001] This invention belongs to the field of power grid stability control technology, specifically, it relates to a method and system for unified control of rotational inertia of widely distributed new energy power stations. Background Technology

[0002] New power systems characterized by a high proportion of renewable energy and power electronic equipment suffer from insufficient rotational inertia, resulting in large frequency fluctuations and a susceptibility to frequency instability due to the lack of rotating equipment. Therefore, enabling renewable energy generation such as wind and solar power to achieve virtual rotational inertia through power electronic control is a crucial means to address the frequency stability issues caused by insufficient rotational inertia in these new power systems.

[0003] In existing technologies, wind farms and photovoltaic stations provide rotational inertia by adding a power component to their power output that is related to the rate of frequency change and hinders frequency variation. The rotational inertia of this power component adaptively changes with the rate of change of angular frequency. Although each new energy device or station can provide virtual rotational inertia, because these devices or stations can only provide rotational inertia based on locally monitored frequencies and do not know how much rotational inertia the overall power grid needs, new safety and stability problems such as over-adjustment, reverse adjustment, and oscillations arise. Moreover, although the grid frequency is consistent in the quasi-steady state, it is actually inconsistent in transient and dynamic processes. For example, during low-frequency power oscillations, the frequencies on both sides of the oscillation center are above and below 50Hz, and the directions of frequency acceleration are also inconsistent. This causes different trends in rotational inertia, resulting in local rotational inertia adjustments potentially being inversely proportional to the overall grid-wide required rotational inertia adjustment. Although adaptive control of rotational inertia can improve the problems caused by over-adjustment and reverse adjustment to some extent, due to the incompleteness of local information, the above problems cannot be overcome by decentralized local rotational inertia control. In addition, frequency propagation actually takes time. Frequency anomalies at the fault source usually take hundreds of milliseconds to several seconds to propagate to other parts of the provincial and higher-level power grids. Therefore, the virtual rotational inertia achieved independently by each station based on local measurements cannot solve the problem of simultaneity or synchronization.

[0004] Furthermore, current technologies lack methods for controlling rotational inertia based on the real-time needs of the large power grid, and also lack methods for synchronizing the rotational inertia provided by various power stations. Existing virtual synchronous machine rotational inertia adaptive optimization control methods all rely on new energy equipment or energy storage within the power station to realize the virtual rotational inertia of a particular new energy power station relative to the power grid. Although these methods provide changing rotational inertia based on local information, their contribution to the overall rotational inertia of the power grid is uncertain, potentially causing negative impacts such as over-adjustment, reverse adjustment, and oscillation. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and system for unified control of the rotational inertia of widely distributed renewable energy power plants. This system enables synchronous and coordinated control of these power plants to meet the real-time rotational inertia requirements of the regional power grid. Based on global information such as the frequency of the regional AC power grid hub bus and the current distribution of generator inertia, the system provides a real-time assessment of the current rotational inertia requirements of the regional power grid. The system treats the converter resources of the regional power grid, which can be rapidly adjusted at the millisecond level, as a virtual synchronous generator unit. Using synchronous acquisition and control technology, it achieves coordinated control of converter regulation resources such as wind power, photovoltaic power, and energy storage across the entire network. This avoids the problems of over-adjustment, under-adjustment, reverse adjustment, and oscillation of the overall rotational inertia of the regional power grid caused by the dispersed rotational inertia provided by each renewable energy power plant based on local information, without considering the rotational inertia contributions of other power plants, and lacking coordination. It also avoids the difficulty in achieving synchronization of dispersed inertia control.

[0006] The present invention adopts the following technical solution.

[0007] This invention also proposes a method for unified control of rotational inertia in widely distributed renewable energy power plants, comprising:

[0008] An inertial collaborative control master station is set up in the regional power grid, which acquires global measurement information of the regional power grid.

[0009] The inertia collaborative control master station calculates the minimum required rotational inertia of the regional power grid based on global measurement information; using the minimum required rotational inertia of the regional power grid, the rotational inertia of conventional units in the regional power grid, and the virtual rotational inertia of renewable energy power plants not participating in collaborative control, it determines the virtual rotational inertia adjustment amount required by the regional power grid in real time; based on the real-time frequency of the highest voltage level bus in the regional power grid, it uses the virtual rotational inertia adjustment amount required by the regional power grid in real time to determine the active power adjustment amount required by the regional power grid in real time, and allocates the active power adjustment amount to each renewable energy power plant participating in collaborative control; the instruction composed of the active power adjustment amount allocated to each renewable energy power plant participating in collaborative control and the time stamp corresponding to the real-time frequency of the highest voltage level bus is sent to each inertia collaborative control substation;

[0010] Each inertial coordination control substation that receives the instruction uses the instruction received this time, the instruction received last time, and the time stamp of the instruction received this time to determine the corrected active power adjustment amount using a linear extrapolation method; based on the corrected active power adjustment amount, it controls the output power of each converter in the new energy power station.

[0011] Global measurement information for the regional power grid includes: the maximum active power disturbance predicted based on the current state of the regional power grid, the duration during which primary frequency regulation has not yet taken effect after the disturbance, the real-time frequency of the highest voltage level bus, and the corresponding time scale.

[0012] The minimum rotational inertia required for a regional power grid satisfies the following relationship:

[0013]

[0014] In the formula, J sys-min ΔP is the minimum rotational inertia required for the regional power grid. max ΔT is the maximum active power disturbance predicted based on the current state of the power grid. r The duration during which the frequency modulation has not yet taken effect after the disturbance is denoted as Δf, which is taken as 0.5s in the example. v f is the allowable value for the frequency variation. e This is the rated frequency of the power grid.

[0015] The virtual moment of inertia adjustment required by the regional power grid in real time satisfies the following relationship:

[0016] J sys-v =k×J sys-min -J r -J na

[0017] In the formula, J sys-v J represents the virtual moment of inertia adjustment required by the power grid in real time, where k is the margin coefficient. r J represents the rotational inertia of conventional generating units in a regional power grid. na The virtual rotational inertia of new energy power stations that do not participate in coordinated control.

[0018] The active power regulation required by the regional power grid in real time satisfies the following relationship:

[0019]

[0020] In the formula, P sys-v ω = 2πf, where f is the real-time active power regulation required by the regional power grid.

[0021] The inertia-coordinated control master station calculates the active power regulation amount allocated to the i-th renewable energy power station participating in the coordinated control based on the proportion of the adjustable power of the i-th renewable energy power station participating in the coordinated control to the total adjustable power of all renewable energy power stations participating in the coordinated control, and based on the active power regulation amount required by the regional power grid in real time.

[0022] Corrected active power regulation P sys-v-i-r It satisfies the following relationship:

[0023]

[0024] In the formula, P sys-v-i T tabP represents the active power adjustment and time scale in the command received by the i-th inertia cooperative control substation this time. sys-v-i-0 T tab-0 T represents the active power adjustment and time stamp in the command previously received by the i-th inertia cooperative control substation. tab-s-i Let P be the time stamp of the instruction received by the i-th inertial cooperative control substation this time. sys-v-i-r This represents the active power adjustment amount corrected for the i-th inertia-coordinated control substation.

[0025] The inertia-coordinated control substation calculates the active power adjustment amount that each converter needs to add when outputting active power, based on the proportion of the adjustable margin of each converter in the total adjustable margin of all converters in the new energy power station and the corrected active power adjustment amount.

[0026] The active power regulation allocated to each participating renewable energy power station and the command, composed of the time stamp corresponding to the real-time frequency of the highest voltage level bus, are simultaneously sent to each inertial coordinated control substation via multicast, including:

[0027] Based on the instruction length determined according to the message length allowed by the communication protocol, the new energy power stations participating in the coordinated control are divided into multiple groups, and instructions are sent sequentially to the new energy power stations in each group during each control cycle.

[0028] This invention also proposes a system for unified control of rotational inertia in widely distributed renewable energy power plants, comprising:

[0029] The inertial collaborative control master station is set up in the regional power grid and the inertial collaborative control substation is set up in each new energy power station;

[0030] The inertia-coordinated control master station is used to acquire global measurement information of the regional power grid; calculate the minimum required rotational inertia of the regional power grid based on the global measurement information; determine the virtual rotational inertia adjustment amount required by the regional power grid in real time using the minimum required rotational inertia of the regional power grid, the rotational inertia of conventional units in the regional power grid, and the virtual rotational inertia of renewable energy power plants that do not participate in the coordinated control; determine the active power adjustment amount required by the regional power grid in real time based on the real-time frequency of the highest voltage level bus in the regional power grid, and allocate the active power adjustment amount to each renewable energy power plant participating in the coordinated control; the instruction composed of the active power adjustment amount allocated to each renewable energy power plant participating in the coordinated control and the time stamp corresponding to the real-time frequency of the highest voltage level bus is sent to each inertia-coordinated control substation.

[0031] The inertia-coordinated control substation is used to determine the corrected active power regulation amount by using the currently received command, the previously received command, and the timestamp of the currently received command, and by employing a linear extrapolation method; based on the corrected active power regulation amount, it controls the output power of each converter in the new energy power station.

[0032] The present invention is also a terminal, including a processor and a storage medium; the storage medium is used to store instructions; the processor is used to perform operations according to the instructions to execute the steps of the method.

[0033] The present invention is also a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method.

[0034] The beneficial effects of this invention are that, compared with the prior art, it at least includes the following: by setting up an inertia collaborative control master station in the regional power grid, global collaborative control is performed based on the global measurement information of the regional power grid, so that the rotational inertia provided by the virtual generators of the whole network is exactly equal to the actual demand for the current rotational inertia, avoiding over-adjustment, under-adjustment, reverse adjustment and oscillation caused by each new energy or energy storage station providing rotational inertia based on local information.

[0035] Each inertia-coordinated control substation that receives the command uses the command received this time, the command received last time, and the time stamp of the command received this time to determine the corrected active power adjustment using a linear extrapolation method. Based on the high-precision time stamp, synchronous measurement and synchronous control are achieved, and the delay is compensated for. This allows the commands of the centralized coordinated control master station to be executed synchronously at the substations, solving the problem that it is difficult to achieve synchronous control at current new energy power plants based on the decentralized and independent provision of virtual rotational inertia by local measurement. Attached Figure Description

[0036] Figure 1 This is a flowchart of the method for unified control of rotational inertia of widely distributed new energy power stations proposed in this invention;

[0037] Figure 2 This is a working architecture diagram of the unified control system for rotational inertia of widely distributed new energy power stations proposed in this invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0039] This invention proposes a method for unified control of the rotational inertia of widely distributed renewable energy power plants. It enables synchronous and coordinated control of these power plants to meet the rotational inertia requirements of the power grid, achieving real-time unified control of the rotational inertia of the regional power grid. Figure 1 As shown, the method includes:

[0040] Step 1: Set up an inertia collaborative control master station in the regional power grid; the inertia collaborative control master station acquires global measurement information of the regional power grid and calculates the minimum rotational inertia required by the regional power grid based on the global measurement information.

[0041] In this embodiment, the regional power grid can be the entire AC power grid or a part of the AC power grid; all new energy power stations within the regional power grid share a common inertial collaborative control master station; the global measurement information of the regional power grid includes, but is not limited to: the real-time frequency and corresponding time scale of the highest voltage level bus;

[0042] Because the regional power grid master station calculates the minimum rotational inertia requirement of the current regional power grid based on unified measurements, it avoids the overestimation, underestimation, or reversal of the total rotational inertia requirement caused by each new energy or energy storage power station's virtual rotational inertia control master station independently calculating its own station's rotational inertia requirement based on local measurement information, as well as the oscillations caused by subsequent adjustments. The inertia collaborative control master station obtains global measurement information, overcoming the limitations of local measurement information. Based on the shared inertia of the regional power grid, the collaborative control master station can accurately calculate the regional power grid's rotational inertia requirement, thus avoiding over-adjustment, under-adjustment, reverse adjustment, and oscillations caused by the lack of rapid and coordinated independent corrections.

[0043] In addition, due to communication delays between the collaborative control master station and the widely distributed field stations, different algorithms exist for calculating electrical measurements at the same time segment at each field station, and the response performance of each execution substation varies. Therefore, the control of the widely distributed field stations by the moment of inertia control master station cannot ignore the delays in measurement, acquisition, and control as it does with the acquisition and control of different equipment within the same field station by the station-area moment of inertia control master station. Measures need to be taken to conduct actual delay measurements and delay compensation to ensure synchronous control of the widely distributed field stations and achieve the expected results.

[0044] In this embodiment, the current frequency f and the corresponding time scale T of the highest voltage level hub bus of the regional power grid are periodically collected. tab The inertia collaborative control master station evaluates the minimum rotational inertia required by the regional power grid in real time based on the collected information from the hub bus, satisfying the following relationship:

[0045]

[0046] In the formula, J sys-min ΔP is the minimum rotational inertia required for the regional power grid.max ΔT is the maximum active power disturbance predicted based on the current state of the regional power grid. r The duration during which the frequency modulation has not yet taken effect after the disturbance is denoted as Δf, which is taken as 0.5s in the example. v The allowable value for frequency variation is 0.1Hz in this example. e The rated frequency of the power grid is 50Hz, which is used in this example.

[0047] Step 2: The inertia collaborative control master station uses the minimum required rotational inertia of the regional power grid, the rotational inertia of conventional units in the regional power grid, and the virtual rotational inertia of new energy power plants that do not participate in collaborative control to determine the virtual rotational inertia adjustment amount required by the regional power grid in real time, satisfying the following relationship:

[0048] J sys-v =k×J sys-min -J r -J na

[0049] In the formula, J sys-v J represents the virtual moment of inertia adjustment required by the power grid in real time, k is the margin coefficient, and in this example, it is taken as 1.1. r J represents the rotational inertia of conventional generating units in a regional power grid. na The virtual rotational inertia of new energy power stations that do not participate in coordinated control;

[0050] In this context, the rotational inertia of conventional generating units in the regional power grid and the virtual rotational inertia of new energy power plants that do not participate in coordinated control are fixed values. However, the minimum rotational inertia required by the regional power grid is a variable value that changes over time. Therefore, the virtual rotational inertia adjustment required by the regional power grid in real time is also a variable value that changes over time.

[0051] Step 3: The inertia collaborative control master station determines the active power regulation required by the regional power grid in real time based on the real-time frequency of the highest voltage level bus in the regional power grid and the virtual rotational inertia regulation required by the regional power grid in real time, and distributes the active power regulation to each new energy power station participating in the collaborative control.

[0052] The real-time active power regulation required by the determined regional power grid satisfies the following relationship:

[0053]

[0054] In the formula, P sys-v The active power regulation required by the regional power grid in real time is ω=2πf, where f is the real-time frequency of the highest voltage level bus in the regional power grid;

[0055] Based on the proportion of the adjustable power of the i-th renewable energy power station participating in the coordinated control to the total adjustable power of all renewable energy power stations participating in the coordinated control, calculate the active power regulation amount P allocated to the i-th renewable energy power station participating in the coordinated control. sys-v-i It satisfies the following relationship:

[0056]

[0057] In the formula, P sys-v-i P represents the active power regulation allocated to the i-th renewable energy power station participating in the coordinated control. a-i Let N be the adjustable power of the i-th renewable energy power station participating in the coordinated control, and N be the total number of renewable energy power stations participating in the coordinated control.

[0058] In this invention, the regional power grid rotational inertia collaborative control master station determines the corresponding real-time active power adjustment amount based on the virtual rotational inertia required by the regional power grid in real time, and uniformly allocates and determines the active power adjustment amount and virtual rotational inertia adjustment amount required by each new energy power station. This avoids the problems of over-adjustment, under-adjustment, reverse adjustment, or even oscillation of the overall virtual rotational inertia adjustment amount of the regional power grid, which are caused by each new energy power station calculating the rotational inertia adjustment amount required by the station based only on the local frequency and other electrical information measured by the station, as in other methods where each new energy power station independently provides virtual rotational inertia.

[0059] Furthermore, the active power regulation of each new energy power station, determined based on the virtual rotational inertia regulation required by the regional power grid in real time, is the basis for achieving the unification of rotational inertia of widely distributed new energy power stations.

[0060] Step 4: The inertial collaborative control master station will construct an instruction by combining the active power regulation amount allocated to each new energy power station participating in the collaborative control with the time stamp corresponding to the real-time frequency of the highest voltage level bus; the instruction will be sent simultaneously to the inertial collaborative control substations in each new energy power station via multicast.

[0061] Specifically, in existing wide-area control systems of power systems, such as AGC automatic generation control and AVC automatic voltage control, since these are second- or minute-level controls, point-to-point command issuance is used. Furthermore, other literature on rotational inertia control implements command issuance within the power station, controlling at most a few dozen converters; even with point-to-point command issuance, the time it takes for each controlled object to receive the command is not significantly different, thus point-to-point command issuance is also used. However, this invention proposes that inertia collaborative control uses a multicast method when issuing commands from the master station, broadcasting P... sys-v-i and T tabThe instructions are sent to each new energy power station simultaneously via multicast, rather than in a point-to-point, round-robin manner. This is to ensure that each new energy power station receives the instructions from the inertia collaborative control master station as simultaneously as possible. This avoids the situation where there are many controlled objects and the point-to-point, round-robin method results in significant differences in the time it takes for the controlled objects to receive the instructions, leading to large differences in the instruction execution time and failing to achieve the effect of collaborative control in generating the target virtual rotational inertia.

[0062] Because multicast commands are used, a single command must contain instructions from all controlled power stations. This results in different controlled power stations being able to see instructions from other controlled power stations, leading to a lack of confidentiality. To address this issue, the command information from each power station is encrypted and encoded into the overall command according to agreed-upon rules. When the number of controlled power stations is large and the total command length exceeds the message length allowed by the communication protocol, the commands for the controlled entities are grouped and sent point-to-point. In this example, there are 2000 new energy power stations under control, which can be grouped into sets of 200, with multicast commands sent 10 times per control cycle.

[0063] The method proposed in this invention continuously and periodically calculates the required rotational inertia adjustment amount and its corresponding active power adjustment amount of the regional power grid based on real-time information such as the hub bus frequency, the number of grid-connected generating units, and the existing rotational inertia. This amount is then uniformly allocated in real time to each widely distributed renewable energy power station. This ensures that the total rotational inertia provided by the virtual generators of the renewable energy power stations in the regional power grid is exactly equal to the actual rotational inertia demand of the regional power grid. This avoids the situation where each renewable energy or energy storage power station independently provides rotational inertia based on local frequency measurement information without considering the contribution of other generating units, which can easily lead to over-adjustment, under-adjustment, reverse adjustment, and oscillation of the overall rotational inertia of the regional power grid.

[0064] Step 5: Each inertial coordinated control substation that receives the instruction uses the instruction received this time, the instruction received last time, and the time stamp of the instruction received this time to determine the corrected active power adjustment amount by using the linear extrapolation method.

[0065] Based on the trend of active power values ​​changing with time in recently received adjacent historical commands, the correction that the current command from the co-control substation should make to the power command due to the delay is estimated. This is typically done using linear extrapolation to calculate the power change with delay. This method only has directional deviations at non-smooth extreme points. However, for millisecond-level continuous control of a dynamic process lasting several seconds, a large command error at one point (one time step) has almost no impact on the overall control effect of the dynamic process over those few seconds. The specific correction method is as follows:

[0066] In this embodiment, the time stamp T of the instruction received by the i-th inertial cooperative control substation from the inertial cooperative control master station is recorded. tab-s-i According to the P instruction sys-v-i and Ttab And the active power adjustment P recorded in the last received inertial cooperative control master station command. sys-v-i-0 and time scale T tab-0 Calculate the active power adjustment P that should be made in the command due to the delay in receiving the command from the master station at the substation. sys-v-i The correction is performed to obtain the corrected active power regulation P. sys-v-i-r It satisfies the following relationship:

[0067]

[0068] In the formula, P sys-v-i T tab P represents the active power adjustment and time scale in the command received by the i-th inertia cooperative control substation this time. sys-v-i-0 T tab-0 T represents the active power adjustment and time stamp in the command previously received by the i-th inertia cooperative control substation. tab-s-i Let P be the time stamp of the instruction received by the i-th inertial cooperative control substation this time. sys-v-i-r This represents the active power adjustment amount corrected for the i-th inertia-coordinated control substation.

[0069] In order to realize the synchronous acquisition and synchronous control of widely distributed collaborative control substations by a centralized collaborative control master station, this invention proposes a method to measure the command delay at the substation and compensate for the delay based on the power change trend in the master station command at the most recent time step. This method can solve the problem of sacrificing the speed of control caused by the conventional fixed delay compensation at the master station.

[0070] Since the inertial collaborative control master station needs to command and control the inertial collaborative control substations in a wide-area distribution of new energy power stations, the latency of the communication system composed of transmission distance, relay devices, routers, encryption devices, etc. is unavoidable. The latency of the acquisition devices in different new energy power stations also varies, and latency of 70ms to hundreds of milliseconds or even longer is unavoidable. Therefore, synchronization mechanisms such as wide-area synchronous acquisition, wide-area synchronous control, and latency compensation are involved. However, these synchronization mechanisms do not need to be considered when providing rotational inertia in the existing new energy power station with PCS. The method proposed in this invention adds high-precision time stamps during data acquisition and when the collaborative control substation receives the command. Based on the real-time measurement of the latency when the collaborative control substation receives the command, the above-mentioned real-time latency compensation method based entirely on the measured latency of the substation is proposed. The latency of each substation is different and the latency of each substation is dynamically changing. Existing delay compensation methods based on actual measurements typically perform fixed delay compensation at the master station. When the slave station receives a command, it checks whether the fixed delay has been reached. If it has not been reached, it waits for the fixed delay to be reached. Although this can convert the variable delay into a fixed delay, it sacrifices the speed of control.

[0071] Step 6: Based on the corrected active power regulation, control the output power of each converter in the new energy power station.

[0072] The inertia-coordinated control substation allocates the corrected active power regulation amount assigned to one of the participating renewable energy power plants to each converter based on the proportion of each converter's adjustable margin to the total adjustable margin of all converters within the renewable energy power plant. This results in the active power adjustment amount P that each converter needs to add when outputting active power. sys-v-i-r-j It satisfies the following relationship:

[0073]

[0074] In the formula, P sys-v-i-r-j P represents the active power adjustment allocated to the j-th converter within the i-th renewable energy power station participating in the coordinated control. pcs-j Let M be the active power adjustable margin of the j-th converter, and M be the total number of converters in the i-th renewable energy power station.

[0075] The control substation uses the Goose or UDP Modbus communication protocol to transmit the active power adjustment P that needs to be added to the output active power of each converter. sys-v-i-r-j Send to each converter power supply and return to step 1.

[0076] This invention also proposes a system for unified control of rotational inertia in widely distributed renewable energy power plants, comprising:

[0077] The inertial collaborative control master station is set up in the regional power grid and the inertial collaborative control substation is set up in each new energy power station;

[0078] The inertia-coordinated control master station is used to acquire global measurement information of the regional power grid; calculate the minimum required rotational inertia of the regional power grid based on the global measurement information; determine the virtual rotational inertia adjustment amount required by the regional power grid in real time using the minimum required rotational inertia of the regional power grid, the rotational inertia of conventional units in the regional power grid, and the virtual rotational inertia of renewable energy power plants that do not participate in the coordinated control; determine the active power adjustment amount required by the regional power grid in real time based on the real-time frequency of the highest voltage level bus in the regional power grid, and allocate the active power adjustment amount to each renewable energy power plant participating in the coordinated control; the instruction composed of the active power adjustment amount allocated to each renewable energy power plant participating in the coordinated control and the time stamp corresponding to the real-time frequency of the highest voltage level bus is sent to each inertia-coordinated control substation.

[0079] The inertia-coordinated control substation is used to determine the corrected active power regulation amount by using the currently received command, the previously received command, and the timestamp of the currently received command, and by employing a linear extrapolation method; based on the corrected active power regulation amount, it controls the output power of each converter in the new energy power station.

[0080] Based on the above method for obtaining the real-time required rotational inertia of the power grid through millisecond-level collaborative control of all renewable energy power stations, a millisecond-level collaborative control system for the rotational inertia of all renewable energy power stations is proposed. The system workflow architecture is as follows: Figure 2 . Figure 2 The system includes a phasor data millisecond-level synchronous acquisition device, a regional power grid new energy power station millisecond-level collaborative control master station for rotational inertia, and inertia collaborative control substations deployed in wind farms, photovoltaic stations, and electrochemical energy storage stations, respectively. The functions of each main device are as follows:

[0081] 1) The phasor data millisecond-level synchronous acquisition device enables rapid synchronous acquisition of quantities directly related to millisecond-level control decisions, such as hub bus voltage, active power of grid-connected lines of new energy power plants, and real-time maximum available capacity of new energy power plants. The acquisition cycle is no more than 10ms, the acquisition device delay does not exceed the set value, preferably 40ms, and the time scale accuracy is less than 1μs. In the embodiment, the synchronous acquisition information uploading cycle is 10ms, and the phasor data millisecond-level synchronous acquisition device is hard-wired with the hub bus and the convergence lines of each new energy power plant.

[0082] 2) The master station device for millisecond-level collaborative control of the rotational inertia of all renewable energy power plants is responsible for collecting data on the hub bus voltage, the active power of the grid-connected lines of renewable energy power plants, and the real-time maximum available capacity of renewable energy power plants, and completing time synchronization to obtain a synchronized power system status profile. Based on this synchronized profile information, control decisions on the rotational inertia power of each renewable energy power plant are made according to steps 1-4, and power commands are sent to the collaborative control substations of each renewable energy power plant using multicast synchronization (or on-demand delivery when there are few controlled objects). The multicast delivery cycle of the master station communication commands can be set in the range of 20-50ms, preferably 30ms, and the delay of the master station device is less than the set value, preferably 40ms.

[0083] 3) The inertial control substations located in wind farms, photovoltaic stations, and electrochemical energy storage stations receive commands from the master control station. After delay compensation, they distribute the rotational inertial power to the wind power, photovoltaic, or energy storage control units or PCS within each new energy station. The distribution is based on the real-time power and available capacity of the generating units transmitted by each control unit. The substation command response delay should be less than a set value, preferably 5ms, and the completion time for step commands should be less than 60ms. The substation communication command issuance cycle is 20ms, or completely corresponds to the master station command cycle; among them, the wind farm control unit or inverter PCS, the photovoltaic station control unit or inverter PCS, and the electrochemical energy storage station control unit or converter PCS transmit real-time power and available capacity to the inertial control substations in millisecond cycles.

[0084] The whole-network inertia collaborative control system comprises three levels: master station, substations, and execution devices. It sets requirements for the time response performance of the master station, substations, and execution devices, as well as the synchronization of measurement and execution. Other rotational inertia collaborative control schemes are implemented in the station domain, typically consisting of only two levels: collaborative control devices and execution devices. Consequently, there are no requirements for the grid-level master station, nor for the time performance between the grid-level master station and the collaborative control substations within the station, and no need for synchronization of measurement and execution.

[0085] This invention continuously and periodically calculates the required rotational inertia adjustment and its corresponding active power adjustment for the regional power grid based on real-time information such as the hub bus frequency, the number of generating units on the grid, and existing rotational inertia. This information is then uniformly allocated in real-time to the widely distributed renewable energy power stations. This ensures that the total rotational inertia provided by the virtual generators of the renewable energy power stations in the regional power grid is exactly equal to the actual rotational inertia demand of the regional power grid. This avoids the situation where each renewable energy or energy storage power station independently provides rotational inertia based on local frequency measurements without considering the contribution of other generating units, which can easily lead to over-adjustment, under-adjustment, reverse adjustment, and oscillation of the overall rotational inertia of the regional power grid. To achieve synchronous control of the widely distributed collaborative control substations by the centralized collaborative control master station, a method is proposed that measures the command delay at the substation and compensates for the delay based on the power change trend in the master station command at the most recent time step. This solves the problem of sacrificing control speed caused by conventional fixed delay compensation at the master station.

[0086] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0087] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0088] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0089] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for unified control of rotational inertia of widely distributed new energy power stations, characterized in that, include: An inertial collaborative control master station is set up in the regional power grid, which acquires global measurement information of the regional power grid. The inertia collaborative control master station calculates the minimum required rotational inertia of the regional power grid based on global measurement information; using the minimum required rotational inertia of the regional power grid, the rotational inertia of conventional units in the regional power grid, and the virtual rotational inertia of renewable energy power plants not participating in collaborative control, it determines the virtual rotational inertia adjustment amount required by the regional power grid in real time; based on the real-time frequency of the highest voltage level bus in the regional power grid, it uses the virtual rotational inertia adjustment amount required by the regional power grid in real time to determine the active power adjustment amount required by the regional power grid in real time, and allocates the active power adjustment amount to each renewable energy power plant participating in collaborative control; the instruction composed of the active power adjustment amount allocated to each renewable energy power plant participating in collaborative control and the time stamp corresponding to the real-time frequency of the highest voltage level bus is sent to each inertia collaborative control substation; Each inertial coordinated control substation that receives the instruction uses the instruction received this time, the instruction received last time, and the time stamp of the instruction received this time to determine the corrected active power adjustment amount by using the linear extrapolation method. Based on the corrected active power regulation, the output power of each converter in the new energy power station is controlled.

2. The method for unified control of rotational inertia of widely distributed new energy power stations according to claim 1, characterized in that, Global measurement information for the regional power grid includes: the maximum active power disturbance predicted based on the current state of the regional power grid, the duration during which primary frequency regulation has not yet taken effect after the disturbance, the real-time frequency of the highest voltage level bus, and the corresponding time scale.

3. The method for unified control of rotational inertia of widely distributed new energy power stations according to claim 2, characterized in that, The minimum rotational inertia required for a regional power grid satisfies the following relationship: In the formula, J sys-min ΔP is the minimum rotational inertia required for the regional power grid. max ΔT is the maximum active power disturbance predicted based on the current state of the power grid. r The duration during which the frequency modulation has not yet taken effect after the disturbance is denoted as Δf, which is taken as 0.5s in the example. v f is the allowable value for the frequency variation. e This is the rated frequency of the power grid.

4. The method for unified control of rotational inertia of widely distributed new energy power stations according to claim 3, characterized in that, The virtual moment of inertia adjustment required by the regional power grid in real time satisfies the following relationship: J sys-v <k×J sys-min -J r -J na In the formula, J sys-v J represents the virtual moment of inertia adjustment required by the power grid in real time, where k is the margin coefficient. r J represents the rotational inertia of conventional generating units in a regional power grid. na The virtual rotational inertia of new energy power stations that do not participate in coordinated control.

5. The method for unified control of rotational inertia of widely distributed new energy power stations according to claim 4, characterized in that, The active power regulation required by the regional power grid in real time satisfies the following relationship: In the formula, P sys-v ω = 2πf, where f is the real-time active power regulation required by the regional power grid.

6. The method for unified control of rotational inertia of widely distributed new energy power stations according to claim 5, characterized in that, The inertia-coordinated control master station calculates the active power regulation amount allocated to the i-th renewable energy power station participating in the coordinated control based on the proportion of the adjustable power of the i-th renewable energy power station participating in the coordinated control to the total adjustable power of all renewable energy power stations participating in the coordinated control, and based on the active power regulation amount required by the regional power grid in real time.

7. The method for unified control of rotational inertia of widely distributed new energy power stations according to claim 6, characterized in that, Corrected active power regulation P sys-v-i-r It satisfies the following relationship: In the formula, P sys-v-i T tab P represents the active power adjustment and time scale in the command received by the i-th inertia cooperative control substation this time. sys-v-i-0 T tab-0 T represents the active power adjustment and time stamp in the command previously received by the i-th inertia cooperative control substation. tab-s-i Let P be the time stamp of the instruction received by the i-th inertial cooperative control substation this time. sys-v-i-r This represents the active power adjustment amount corrected for the i-th inertia-coordinated control substation.

8. The method for unified control of rotational inertia of widely distributed new energy power stations according to claim 7, characterized in that, The inertia-coordinated control substation calculates the active power adjustment amount that each converter needs to add when outputting active power, based on the proportion of the adjustable margin of each converter in the total adjustable margin of all converters in the new energy power station and the corrected active power adjustment amount.

9. The method for unified control of rotational inertia of widely distributed new energy power stations according to claim 1, characterized in that, The active power regulation allocated to each participating renewable energy power station and the command, composed of the time stamp corresponding to the real-time frequency of the highest voltage level bus, are simultaneously sent to each inertial coordinated control substation via multicast, including: Based on the instruction length determined according to the message length allowed by the communication protocol, the new energy power stations participating in the coordinated control are divided into multiple groups, and instructions are sent sequentially to the new energy power stations in each group during each control cycle.

10. A system for unified control of rotational inertia of widely distributed new energy power stations, characterized in that, include: The inertial collaborative control master station is set up in the regional power grid and the inertial collaborative control substation is set up in each new energy power station; The inertia-coordinated control master station is used to acquire global measurement information of the regional power grid; calculate the minimum required rotational inertia of the regional power grid based on the global measurement information; determine the virtual rotational inertia adjustment amount required by the regional power grid in real time using the minimum required rotational inertia of the regional power grid, the rotational inertia of conventional units in the regional power grid, and the virtual rotational inertia of renewable energy power plants that do not participate in the coordinated control; determine the active power adjustment amount required by the regional power grid in real time based on the real-time frequency of the highest voltage level bus in the regional power grid, and allocate the active power adjustment amount to each renewable energy power plant participating in the coordinated control; the instruction composed of the active power adjustment amount allocated to each renewable energy power plant participating in the coordinated control and the time stamp corresponding to the real-time frequency of the highest voltage level bus is sent to each inertia-coordinated control substation. The inertia-coordinated control substation is used to determine the corrected active power adjustment amount by using the command received this time, the command received last time, and the time stamp of the command received this time, and by using the linear extrapolation method. Based on the corrected active power regulation, the output power of each converter in the new energy power station is controlled.

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