Control method and device based on network following proportion and network construction proportion, equipment and medium

Abstract

The invention provides a control method and device based on a network following proportion and a network construction proportion, equipment and a medium, and relates to the technical field of power systems, and the method comprises the steps: obtaining the system capacity and the device capacity of a power system; wherein the system capacity refers to the sum of rated capacities of various hub substations in the power system, and the device capacity refers to the installation capacity of equipment integrating a network following function and a network construction function in a preset range of the power system; determining a short-circuit ratio according to the system capacity and the device capacity; determining a network following proportion and a network construction proportion according to the short-circuit ratio; acquiring three-phase voltage, three-phase current, direct-current side voltage and direct-current side reference voltage of the power system; and performing pulse width control according to the three-phase voltage, the three-phase current, the direct current side voltage, the direct current side reference voltage, the network following proportion and the network construction proportion. According to the technical scheme, the pulse width of the power system is comprehensively controlled and adjusted based on the network following proportion and the network construction proportion by determining the network following proportion and the network construction proportion.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a control method, device, equipment and medium based on a grid-following ratio and a grid-building ratio. Background Art

[0002] In recent years, the access of a high proportion of power electronic inverters and a high proportion of new energy sources in new power systems has caused the inertia and damping characteristics of the power grid to show a downward trend, affecting the transient synchronization stability of the power system.

[0003] In the prior art, the current static var generator (SVG) is often used for renewable energy grid connection to improve the voltage stability of the power system. The current SVG mostly adopts a grid-following control strategy, which can provide stable voltage support for the power system under a strong grid with a large short-circuit ratio. For a weak grid with a small short-circuit ratio, the advantages of a grid-building SVG are more obvious. The grid-building control adopts a power synchronization method to avoid the interference of voltage and current harmonics under a weak grid. However, there is power fluctuation when multiple machines are connected in parallel, and there is a risk of low-frequency oscillation when operating under a strong grid. In summary, the grid-following inverter has better stability under a strong grid with a large short-circuit ratio, and the grid-building inverter has better stability under a weak grid with a small short-circuit ratio. However, the use of a grid-following or grid-building control power system alone requires preconditions, resulting in poor grid stability of the power system.

[0004] Therefore, there is an urgent need for a control method based on the grid-following ratio and the grid-building ratio to adaptively control the power system and improve the grid stability of the power system. Summary of the invention

[0005] The present invention provides a control method, device, equipment and medium based on the grid-following ratio and the grid-forming ratio, so as to solve the defect in the prior art that the use of grid-following or grid-forming to control the power system alone requires prerequisites, resulting in poor grid stability of the power system. The present invention realizes improving the grid stability of the power system by determining the grid-following ratio and the grid-forming ratio and comprehensively adjusting the pulse width of the power system based on the grid-following ratio and the grid-forming ratio.

[0006] The present invention provides a control method based on a network following ratio and a network building ratio, comprising the following steps.

[0007] Obtain the system capacity and device capacity of the power system; among which, the system capacity refers to the sum of the rated capacities of various hub substations in the power system, and the device capacity refers to the installed capacity of the integrated grid-following function and grid-building function equipment of the power system within a preset range.

[0008] The short-circuit ratio is determined based on the system capacity and device capacity.

[0009] The following network ratio and network construction ratio are determined based on the short-circuit ratio.

[0010] Obtain the three-phase voltage, three-phase current, DC side voltage and DC side reference voltage of the power system.

[0011] The pulse width is controlled according to the three-phase voltage, three-phase current, DC side voltage, DC side reference voltage, grid-following ratio and grid-forming ratio.

[0012] According to a control method based on the network following ratio and the network building ratio provided by the present invention, the short circuit ratio is determined according to the system capacity and the device capacity, including: determining the short circuit ratio according to the ratio of the system capacity to the device capacity.

[0013] According to a control method based on the grid-following ratio and the grid-forming ratio provided by the present invention, the grid-following ratio and the grid-forming ratio are determined according to the short-circuit ratio, including: determining the correspondence between the short-circuit ratio of the power grid and the target grid-forming ratio and the target grid-following ratio; based on the correspondence, obtaining the grid-following ratio and the grid-forming ratio corresponding to the short-circuit ratio.

[0014] According to a control method based on a grid-following ratio and a grid-forming ratio provided by the present invention, the corresponding relationship between a grid short-circuit ratio and a target grid-forming ratio and a target grid-following ratio is determined, including: under a specific grid short-circuit ratio, simulating an initial grid-following ratio and an initial grid-forming ratio of the grid short-circuit ratio to obtain the initial grid-following ratio, the initial grid-forming ratio, and the limit cut-off angle and power amplitude value corresponding to the substation in the power system; wherein the initial grid-following ratio and the initial grid-forming ratio are both at least one; fitting the initial grid-following ratio and the initial grid-forming ratio, the limit cut-off angle and the power amplitude value to obtain a target relationship; determining a cost function according to the target relationship; solving the cost function to obtain a target grid-following ratio and a target grid-forming ratio corresponding to the grid short-circuit ratio, and determining the corresponding relationship based on the grid short-circuit ratio, the target grid-following ratio and the target grid-forming ratio.

[0015] According to a control method based on the network following ratio and the network building ratio provided by the present invention, a cost function is determined according to a target relationship, including: determining a first weight corresponding to a limit resection angle and a second weight determined by a power amplitude value according to the target relationship; and determining a cost function according to the first weight and the second weight.

[0016] According to a control method based on the grid-following ratio and the grid-forming ratio provided by the present invention, pulse width control is performed according to the three-phase voltage, the three-phase current, the DC side voltage, the DC side reference voltage, the grid-following ratio and the grid-forming ratio, including: determining the internal potential phase angle and the internal potential amplitude according to the three-phase voltage, the three-phase current, the DC side voltage, the DC side reference voltage, the grid-following ratio and the grid-forming ratio; determining the three-phase modulation voltage according to the internal potential phase angle and the internal potential amplitude; and performing pulse width control according to the three-phase modulation voltage.

[0017] According to a control method based on the grid-following ratio and the grid-forming ratio provided by the present invention, the internal potential phase angle and the internal potential amplitude are determined according to the three-phase voltage, the three-phase current, the DC side voltage, the DC side reference voltage, the grid-following ratio and the grid-forming ratio, including: determining the two-phase voltage and the two-phase current according to the three-phase voltage and the three-phase current; wherein the two-phase voltage includes a first voltage and a second voltage; determining the grid-following angular frequency according to the first voltage and the grid-following ratio; determining the actual value of reactive power and the actual value of active power according to the first voltage, the second voltage and the two-phase current; determining the internal potential amplitude according to the actual value of reactive power; determining the grid-forming angular frequency according to the DC side voltage, the DC side reference voltage, the actual value of active power and the grid-forming ratio; determining the internal potential phase angle according to the grid-following angular frequency, the grid-forming angular frequency and the angular frequency reference value.

[0018] The present invention also provides a control device based on the network following ratio and the network building ratio, including the following modules.

[0019] The first acquisition module is used to obtain the system capacity and device capacity of the power system; wherein, the system capacity refers to the sum of the rated capacities of various hub substations in the power system, and the device capacity refers to the installed capacity of the integrated network-following function and network-building function equipment of the power system within a preset range.

[0020] The first determination module is used to determine the short-circuit ratio according to the system capacity and the device capacity.

[0021] The second determination module is used to determine the network following ratio and the network building ratio according to the short circuit ratio.

[0022] The second acquisition module is used to acquire the three-phase voltage, three-phase current, DC side voltage and DC side reference voltage of the power system.

[0023] The width control module is used to control the pulse width according to the three-phase voltage, three-phase current, DC side voltage, DC side reference voltage, grid-following ratio and grid-forming ratio.

[0024] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, any of the control methods based on the network following ratio and the network building ratio as described above is implemented.

[0025] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the control method based on the network following ratio and the network building ratio as described above is implemented.

[0026] The present invention also provides a computer program product, including a computer program, which implements any of the above-mentioned control methods based on the network following ratio and the network building ratio when executed by a processor.

[0027] The present invention provides a control method, device, equipment and medium based on the grid-following ratio and the grid-building ratio, by obtaining the system capacity and device capacity of the power system; wherein the system capacity refers to the sum of the rated capacities of various hub substations in the power system, and the device capacity refers to the installed capacity of the integrated grid-following function and the grid-building function equipment of the power system within a preset range; determining the short-circuit ratio according to the system capacity and the device capacity; determining the grid-following ratio and the grid-building ratio according to the short-circuit ratio; obtaining the three-phase voltage, three-phase current, DC side voltage and DC side reference voltage of the power system; and controlling the pulse width according to the three-phase voltage, three-phase current, DC side voltage, DC side reference voltage, the grid-following ratio and the grid-building ratio. The technical solution of the present invention improves the grid stability of the power system of the power grid by determining the grid-following ratio and the grid-building ratio, and adjusting the pulse width of the power system based on the grid-following ratio and the grid-building ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a flow chart of a control method based on a network following ratio and a network building ratio provided by the present invention.

[0030] Figure 2 It is one of the schematic diagrams for simulating setting of the short-circuit ratio of a power grid provided by the present invention.

[0031] Figure 3 This is the second schematic diagram of the simulation setting of the short-circuit ratio of the power grid provided by the present invention.

[0032] Figure 4 It is a schematic diagram for selecting the network following ratio and the network building ratio provided by the present invention.

[0033] Figure 5a It is a schematic diagram of the structure of the power system provided by the present invention.

[0034] Figure 5b It is a schematic diagram of pulse width modulation provided by the present invention.

[0035] Figure 6 It is a structural schematic diagram of a control device based on a network following ratio and a network building ratio provided by the present invention.

[0036] Figure 7 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Combine the following Figure 1-Figure 6 The control method based on the grid-following ratio and the grid-building ratio provided by the present invention is described. The control method based on the grid-following ratio and the grid-building ratio provided by the present invention can be applicable to regulating the stability of the power grid system. The executor of the method can be an electronic device, or a control device based on the grid-following ratio and the grid-building ratio arranged in the electronic device. The control device based on the grid-following ratio and the grid-building ratio can be implemented by software, hardware or a combination of both. Figure 1 : is a flow chart of a control method based on a network following ratio and a network building ratio provided by the present invention, such as Figure 1 As shown, the method includes the following steps 101, 102, 103, 104 and 105.

[0039] Step 101: Obtain system capacity and device capacity of the power system.

[0040] In this step, the system capacity refers to the sum of the rated capacities of various hub substations in the power system, and the device capacity refers to the installed capacity of the integrated network-following function and network-building function equipment in the power system within a preset range.

[0041] Specifically, the power system includes a regional strength identification system, which includes three layers of equipment such as a master station, a substation and an execution station. The regional strength identification system is configured at thermal / hydro / synchronous phase shifters, new energy stations, switch stations and other stations of the power system. The master station is generally set up in the hub substation of the regional power grid of the power system. The substation obtains the rated capacity of various hub substations in the power system. The substation also obtains the installed capacity of the integrated network function and network construction function equipment of the power system within a preset range. The master station receives the installed capacity obtained by the substation and the rated capacity of various hub substations in the power system. The master station summarizes the sum of the rated capacity of various hub substations in the power system obtained by the substation to obtain the system capacity.

[0042] Step 102: Determine the short circuit ratio according to the system capacity and the device capacity.

[0043] In a specific embodiment, determining the short circuit ratio according to the system capacity and the device capacity includes: determining the short circuit ratio according to the ratio of the system capacity to the device capacity; wherein the short circuit ratio , Indicates the system capacity, Indicates the capacity of the device.

[0044] Specifically, after the master station obtains the system capacity and the installation capacity, the short circuit ratio is determined according to the ratio of the system capacity to the device capacity. , Indicates the system capacity, Indicates the capacity of the device.

[0045] Step 103: Determine the network following ratio and network building ratio according to the short circuit ratio.

[0046] Specifically, after the master station obtains the short-circuit ratio, it sends the short-circuit ratio to the execution station, and then the execution station sends the short-circuit ratio to the grid construction and following-grid coordination control system of the power system. Further, the grid construction and following-grid coordination control system calculates the following-grid ratio and the grid construction ratio of the following-grid type and the grid construction type based on the short-circuit ratio and the transient synchronization stability optimization target through the optimization method.

[0047] In this step, the evaluation of transient synchronization stability mainly includes two indicators: the limit cut-off angle after a large disturbance and the power oscillation amplitude after a small disturbance. The first is the limit cut-off angle. For synchronous generators, the larger the damping coefficient, the larger the damping torque, the larger the power angle deceleration area, the smaller the acceleration area, the larger the limit cut-off angle, and the better the transient stability. Similarly, for SVGs with phase angle fusion of the follow-grid and the structure network, the improvement of transient stability can also be achieved by increasing the proportion of the structure network Kp (assuming that the sum of the proportions of the follow-grid and the structure network is 1, then the proportion of the follow-grid is 1-Kp) and increasing the damping coefficient. The second is the power oscillation amplitude after a small disturbance. In a strong network with a short circuit greater than the SCR, the device that applies the structure network strategy will become unstable after a small disturbance. Figure 2 is one of the schematic diagrams of simulating the short-circuit ratio of the power grid provided by the present invention, such as Figure 2 As shown in the figure, the simulation sets the grid short-circuit ratio SCR to 30, and a small disturbance occurs at 0.2s. Figure 2 The ordinate of (a) represents the output voltage (KV), and the abscissa represents time (S). When a small disturbance occurs at 0.2s, the output voltage of the device using the networking strategy remains unchanged. Figure 2 The ordinate of (b) represents the output current (A), and the abscissa represents the time (S). When a small disturbance occurs at 0.2s, the output current of the device using the networking strategy oscillates. Figure 2 The ordinate of (c) represents the output active power (pu), and the abscissa represents the time (S). When a small disturbance occurs at 0.2s, the power of the device using the grid-building strategy oscillates. Therefore, it is determined that in a weak grid with a small short-circuit ratio, the device using the grid-following strategy will become unstable after a small disturbance. Figure 3 FIG. 2 is a second schematic diagram of simulating setting of the short-circuit ratio of a power grid provided by the present invention. Figure 3As shown in the figure, the simulation sets the grid short-circuit ratio SCR to 1, and a small disturbance occurs at 1.2s. Figure 3 The ordinate of (a) represents the output voltage (KV), and the abscissa represents time (S). When a small disturbance occurs at 0.2s, the output voltage of the device using the networking strategy oscillates. Figure 3 The ordinate of (b) represents the output current (A), and the abscissa represents the time (S). When a small disturbance occurs at 0.2s, the output current of the device using the networking strategy oscillates. Figure 3 The ordinate of (c) represents the output active power (pu), and the abscissa represents time (s). When a small disturbance occurs at 0.2s, the power of the device using the network building strategy oscillates. Therefore, the ratio of network building and network following needs to be adjusted according to the short-circuit ratio.

[0048] In order to obtain the optimal target grid-following ratio and target grid-forming ratio under a specific grid short-circuit ratio, three steps need to be completed: First, under a specific grid short-circuit ratio, the target relationship between the limit resection angle, the power oscillation amplitude after a small disturbance, and the grid-following ratio and grid-forming ratio is established. Second, the first weight and the second weight of the two indicators of the limit resection angle and the power oscillation amplitude after a small disturbance are weighed to establish a cost function. Third, the cost function is optimized to obtain the target grid-following ratio and the target grid-forming ratio.

[0049] In a specific implementation, determining the grid-following ratio and the grid-forming ratio according to the short-circuit ratio includes: determining the correspondence between the short-circuit ratio of the power grid and the target grid-forming ratio and the target grid-following ratio; and obtaining the grid-following ratio and the grid-forming ratio corresponding to the short-circuit ratio based on the correspondence.

[0050] In a specific implementation, the correspondence between the short-circuit ratio of a power grid and a target grid-forming ratio and a target grid-following ratio is determined, including: under a specific short-circuit ratio of the power grid, an initial grid-following ratio and an initial grid-forming ratio of the power grid short-circuit ratio are simulated to obtain the initial grid-following ratio and the initial grid-forming ratio, and the limit cut-off angle and power amplitude value corresponding to the substation in the power system; wherein the initial grid-following ratio and the initial grid-forming ratio are both at least one; the initial grid-following ratio and the initial grid-forming ratio, the limit cut-off angle and the power amplitude value are fitted to obtain a target relationship; a cost function is determined according to the target relationship; the cost function is solved to obtain the target grid-following ratio and the target grid-following ratio corresponding to the short-circuit ratio of the power grid, and the corresponding relationship is determined based on the short-circuit ratio of the power grid, the target grid-following ratio and the target grid-following ratio.

[0051] In a specific implementation, determining the cost function according to the target relationship includes: determining a first weight corresponding to the limit resection angle and a second weight determined by the power amplitude value according to the target relationship; and determining the cost function according to the first weight and the second weight.

[0052] Specifically, under a specific grid short-circuit ratio, at least one initial grid-following ratio and initial grid-forming ratio is simulated to obtain the initial grid-following ratio and the initial grid-forming ratio, and the limit resection angle and power amplitude value corresponding to the substation in the power system. The initial grid-following ratio and the initial grid-forming ratio, the limit resection angle and the power amplitude value are fitted by the least squares method to establish a target relationship between the initial grid-following ratio and the initial grid-forming ratio, the limit resection angle and the power amplitude value after a small disturbance. Then, the entropy weight method is used to obtain a first weight corresponding to the limit resection angle and a second weight determined by the power amplitude value, and the first weight and the second weight are linearly weighted to establish a cost function, thereby solving the cost function to obtain the optimal target grid-following ratio and target grid-forming ratio under a specific short-circuit ratio, and determine the corresponding relationship based on the grid short-circuit ratio, the target grid-following ratio and the target grid-forming ratio.

[0053] For example, let the network ratio be kp, and its n values ​​are kp1, ..., kpn. Let the limit resection angles under n network ratios be δ1, ..., δn; and the power amplitude values ​​be A1, ..., An. The data sample X is constructed by the limit resection angles and the power amplitude values, and the data sample X is shown in formula (1).

[0054] (1) First, the least squares method is used to obtain the target relationship between the network ratio and the limit resection angle and oscillation amplitude. The target relationship is shown in formula (2).

[0055] (2) Second, the entropy weight method is used to obtain the first weight corresponding to the limit resection angle and the second weight determined by the power amplitude value. Specifically, first, data standardization is performed to standardize the data of each indicator to eliminate the influence of different dimensions and magnitudes on the evaluation results. Determine the limit resection angle of the positive indicator , for the positive index limit resection angle , the original data can be standardized by the following formula (3).

[0056] (3) Determine the power oscillation amplitude after a small disturbance of the negative indicator , for the negative indicator, the power oscillation amplitude after a small disturbance , the original data can be standardized by the following formula (4).

[0057] (4) Finally, we get the standardized data sample , data sample As shown in formula (5).

[0058] (5) Third, further calculate the first numerical value proportion corresponding to the limit resection angle The second numerical value ratio determined by the power amplitude value , the first numerical weight The calculation of is shown in formula (6), the second value is The calculation of is shown in formula (7).

[0059] (6) (7) Further, the information of the first numerical proportion and the second numerical proportion is calculated, and according to the definition of information entropy in information theory, the first numerical proportion is obtained respectively. The corresponding first information entropy and the second numerical weight The corresponding second information entropy , the first information entropy The calculation of the second information entropy is as shown in formula (8). The calculation of is as shown in formula (9).

[0060] (8) (9) Here, n represents the number of data.

[0061] Fourth, according to the first numerical weight The corresponding first information entropy and the second numerical weight The corresponding second information entropy Calculate the first weight and the second weight . First weight The calculation of the second weight is as shown in formula (10). The calculation of is as shown in formula (11).

[0062] (10) (11) Finally, according to the first weight and the second weight Perform fitting and establish the cost function L. The calculation formula of the cost function L is shown in formula (12).

[0063] (12) The maximum value of the cost function L is further solved to obtain the optimal target grid-following ratio and target grid-forming ratio under the corresponding grid short-circuit ratio. The target grid-following ratio and target grid-forming ratio include the grid-forming ratio Kp and the grid-following ratio of 1-Kp. Figure 4 Schematic diagram of selecting the network following ratio and network building ratio provided by the present invention, such as Figure 4 As shown, the horizontal axis represents the short circuit ratio SCR, and the vertical axis represents the network following ratio and network forming ratio. When the short circuit ratio is large, the network following ratio is increased and the network forming ratio is reduced. When the short circuit ratio is small, the network forming ratio is increased and the network following ratio is reduced.

[0064] In a specific implementation, the grid-building and grid-following coordinated control system of the power system includes a host and a slave, and a real-time control local area network (LAN) for networking; the host is responsible for communicating with the regional strength identification system and configuring an algorithm to decide the ratio of grid-building and grid-following operation of the station; in order to improve the reliability of the power system, the host and the slave can be configured with a master-slave redundancy mode; the real-time control LAN network can be configured with a dual-network redundancy mode to improve the reliability of the networking communication link; the slave communicates with the networking device controller through a Generic Object Oriented Substation Event (GOOSE) network, executes the grid-building and grid-following operation strategy, and adjusts the control simulation parameters in real time.

[0065] Step 104: Acquire the three-phase voltage, three-phase current, DC side voltage and DC side reference voltage of the power system.

[0066] In this step, the three-phase voltage includes a three-phase first voltage U a , three-phase second voltage U b And the three-phase third voltage U c The three-phase current includes the three-phase first current I a , three-phase second current I b and the three-phase third current I c The DC side voltage refers to the voltage value of the DC side in the power system. The DC side reference voltage is a preset voltage value, which is not limited in this embodiment.

[0067] Specifically, after determining the grid-following ratio and the grid-building ratio, the three-phase voltage, three-phase current, DC side voltage and DC side reference voltage of the power system are further obtained.

[0068] Step 105: perform pulse width control according to the three-phase voltage, the three-phase current, the DC side voltage, the DC side reference voltage, the grid-following ratio and the grid-forming ratio.

[0069] In a specific implementation, the grid-following ratio and the grid-forming ratio include the grid-following ratio and the grid-forming ratio; pulse width control is performed according to the three-phase voltage, the three-phase current, the DC side voltage, the DC side reference voltage, the grid-following ratio and the grid-forming ratio, including: determining the internal potential phase angle and the internal potential amplitude according to the three-phase voltage, the three-phase current, the DC side voltage, the DC side reference voltage, the grid-following ratio and the grid-forming ratio; determining the three-phase modulation voltage according to the internal potential phase angle and the internal potential amplitude; and performing pulse width control according to the three-phase modulation voltage.

[0070] In a specific embodiment, the internal potential phase angle and the internal potential amplitude are determined according to the three-phase voltage, the three-phase current, the DC side voltage, the DC side reference voltage, the grid-following ratio and the grid-forming ratio, including: determining the two-phase voltage and the two-phase current according to the three-phase voltage and the three-phase current; wherein the two-phase voltage includes a first voltage and a second voltage; determining the grid-following angular frequency according to the first voltage and the grid-following ratio; determining the actual value of reactive power and the actual value of active power according to the first voltage, the second voltage and the two-phase current; determining the internal potential amplitude according to the actual value of reactive power; determining the grid-forming angular frequency according to the DC side voltage, the DC side reference voltage, the actual value of active power and the grid-forming ratio; determining the internal potential phase angle according to the grid-following angular frequency, the grid-forming angular frequency and the angular frequency reference value.

[0071] Specifically, Figure 5a is a schematic diagram of the structure of the power system provided by the present invention, Figure 5b Schematic diagram of pulse width modulation provided by the present invention, such as Figure 5a As shown in the figure, the device capacity is obtained by integrating the network construction function and the network following function equipment, the short circuit ratio is determined by the power system's differentiated strength identification system, and then the network following ratio and network construction ratio are determined according to the network construction and network following coordination control system. Figure 5b The following network strategy and the network building strategy shown in the figure are used to control the pulse width. In the specific modulation process, the three-phase voltage and the three-phase current are first obtained, and based on the following network strategy, the three-phase voltage and the three-phase current are converted into two-phase voltage and two-phase current. The converted two-phase current includes the two-phase first current I d and the two-phase second current I q The converted two-phase voltage includes the two-phase first voltage U d and the second two-phase voltage U q Then, according to the two-phase first current I d , two-phase second current I q , two-phase first voltage U d and the second two-phase voltage U q Perform power calculation to obtain the actual value of reactive power Q and the actual value of active power P. The actual value of reactive power Q=U d I d +U q I q , the actual value of active power P=Ud I d -U q I q Then, the second voltage U q Input the P (proportional) I (integral) control algorithm, calculate the initial angular frequency, and multiply the initial angular frequency voltage by the grid-following ratio to obtain the grid-following angular frequency. At the same time, obtain the DC side voltage V dc , DC side reference voltage V dcref ,pass , the DC side voltage V dc , DC side reference voltage V dcref Substitute Get V dc The square value and V dcref The square value of V dcref The square value of V dc The square value difference of the DC side voltage is obtained, and the DC voltage difference is input into the PI algorithm to obtain the actual reference value of active power P ref , calculate the actual reference value of active power P ref The difference between the actual value of active power P and 1 / J S (J represents the inertia time constant, S is the integral) and K DW (K DW After multiplying the product of (representing the damping coefficient of the network), the angular frequency adjustment amount is obtained by accumulating the product results. Finally, the angular frequency is adjusted by The product of the meshing ratio Kp is the meshing angular frequency. , get the angular frequency reference value , through the angular frequency reference value , follow the grid angle frequency and the grid angular frequency The sum of the angular frequency is obtained, and the angular frequency sum is calculated by 1 / S integration to finally obtain the internal potential phase angle θ. At the same time, the actual reference value of reactive power Q is obtained. ref , through the reactive power actual reference value Q ref The difference between the reactive power actual value Q and the reactive power difference is obtained, and the reactive power difference and The product of The reactive power integral coefficient is expressed, and the actual amplitude of the internal potential is obtained. The internal potential amplitude E is obtained by summing the actual amplitude of the internal potential with the internal potential reference value E0, and the internal potential amplitude E and the internal potential phase angle θ are converted from two phases to three phases, thereby obtaining the converted three-phase modulation voltage, which includes the three-phase first modulation voltage , three-phase second modulation voltage and the three-phase third modulation voltage Finally, pulse width control (PWM) modulation is performed according to the three-phase modulation voltage, and specifically, the filter inductance, filter capacitor grid voltage effective value, grid side equivalent inductance, etc. can be adjusted, which is not limited in this embodiment.

[0072] The advantage of this setting is that by integrating the grid-following ratio and the grid-forming ratio, the parallel connection of grid-following control and grid-forming control is realized, and pulse width control modulation is finally performed through the parallel first weight and second weight to improve the grid stability of the power system of the power grid.

[0073] The present invention provides a control method, device, equipment and medium based on the grid-following ratio and the grid-building ratio, by obtaining the system capacity and device capacity of the power system; wherein the system capacity refers to the sum of the rated capacities of various hub substations in the power system, and the device capacity refers to the installed capacity of the integrated grid-following function and the grid-building function equipment of the power system within a preset range; determining the short-circuit ratio according to the system capacity and the device capacity; determining the grid-following ratio and the grid-building ratio according to the short-circuit ratio; obtaining the three-phase voltage, three-phase current, DC side voltage and DC side reference voltage of the power system; and controlling the pulse width according to the three-phase voltage, three-phase current, DC side voltage, DC side reference voltage, the grid-following ratio and the grid-building ratio. Based on the above embodiments, the technical scheme of the present invention improves the grid stability of the power system of the power grid by determining the grid-following ratio and the grid-building ratio, and adjusting the pulse width of the power system based on the grid-following ratio and the grid-building ratio.

[0074] The control device based on the network following ratio and the network building ratio provided by the present invention is described below. The control device based on the network following ratio and the network building ratio described below and the control method based on the network following ratio and the network building ratio described above can be referenced to each other.

[0075] Figure 6 is a schematic diagram of the structure of the control device based on the network following ratio and the network building ratio provided by the present invention, referring to Figure 6 As shown, the control device 600 based on the network following ratio and the network building ratio includes: a first acquisition module 601, a first determination module 602, a second determination module 603, a second acquisition module 604 and a width control module 605.

[0076] The first acquisition module 601 is used to obtain the system capacity and device capacity of the power system; wherein the system capacity refers to the sum of the rated capacities of various hub substations in the power system, and the device capacity refers to the installed capacity of the integrated network-following function and network-building function equipment of the power system within a preset range.

[0077] The first determination module 602 is used to determine the short circuit ratio according to the system capacity and the device capacity.

[0078] The second determination module 603 is used to determine the network following ratio and the network building ratio according to the short circuit ratio.

[0079] The second acquisition module 604 is used to acquire the three-phase voltage, three-phase current, DC side voltage and DC side reference voltage of the power system.

[0080] The width control module 605 is used to control the pulse width according to the three-phase voltage, the three-phase current, the DC side voltage, the DC side reference voltage, the grid-following ratio and the grid-forming ratio.

[0081] In an exemplary embodiment, the first determination module 602 is specifically configured to determine the short circuit ratio according to a ratio of the system capacity to the device capacity.

[0082] In an exemplary embodiment, the second determination module 603 is specifically used to: determine the correspondence between the short-circuit ratio of the power grid and the target grid-forming ratio and the target grid-following ratio; and obtain the grid-following ratio and grid-forming ratio corresponding to the short-circuit ratio based on the correspondence.

[0083] In an example embodiment, the second determination module 603 determines the correspondence between the grid short-circuit ratio and the target grid-forming ratio and the target grid-following ratio, and is specifically used to: simulate the initial grid-following ratio and the initial grid-forming ratio under a specific grid short-circuit ratio, and obtain the initial grid-following ratio and the initial grid-forming ratio, and the limit resection angle and power amplitude value corresponding to the substation in the power system; wherein the initial grid-following ratio and the initial grid-forming ratio are both at least one; fit the initial grid-following ratio and the initial grid-forming ratio, the limit resection angle and the power amplitude value to obtain the target relationship; determine the cost function according to the target relationship; solve the cost function to obtain the target grid-following ratio and the target grid-forming ratio corresponding to the grid short-circuit ratio, and determine the correspondence based on the grid short-circuit ratio, the target grid-following ratio and the target grid-forming ratio.

[0084] In an exemplary embodiment, the second determination module 603 determines the cost function according to the target relationship, and is specifically used to: determine the first weight corresponding to the limit resection angle and the second weight determined by the power amplitude value according to the target relationship; determine the cost function according to the first weight and the second weight.

[0085] In an exemplary embodiment, the width control module 605 is specifically used to: determine the internal potential phase angle and the internal potential amplitude according to the three-phase voltage, the three-phase current, the DC side voltage, the DC side reference voltage, the grid-following ratio and the grid-forming ratio; determine the three-phase modulation voltage according to the internal potential phase angle and the internal potential amplitude; and perform pulse width control according to the three-phase modulation voltage.

[0086] In an exemplary embodiment, the width control module 605 determines the internal potential phase angle and the internal potential amplitude according to the three-phase voltage, the three-phase current, the DC side voltage, the DC side reference voltage, the grid-following ratio and the grid-forming ratio, and is specifically used to: determine the two-phase voltage and the two-phase current according to the three-phase voltage and the three-phase current; wherein the two-phase voltage includes a first voltage and a second voltage; determine the grid-following angular frequency according to the first voltage and the grid-following ratio; determine the actual value of reactive power and the actual value of active power according to the first voltage, the second voltage and the two-phase current; determine the internal potential amplitude according to the actual value of reactive power; determine the grid-forming angular frequency according to the DC side voltage, the DC side reference voltage, the actual value of active power and the grid-forming ratio; determine the internal potential phase angle according to the grid-following angular frequency, the grid-forming angular frequency and the angular frequency reference value.

[0087] The device of this embodiment can be used to execute the method of any of the embodiments in the control method side embodiments based on the network following ratio and the network building ratio. Its specific implementation process and technical effects are similar to those in the control method side embodiments based on the network following ratio and the network building ratio. For details, please refer to the detailed introduction in the control method side embodiments based on the network following ratio and the network building ratio, which will not be repeated here.

[0088] Figure 7 is a schematic diagram of the structure of the electronic device provided by the present invention, such as Figure 7 As shown, the electronic device may include: a processor 710, a communication interface 720, a memory 730 and a communication bus 740, wherein the processor 710, the communication interface 720 and the memory 730 communicate with each other through the communication bus 740. The processor 710 may call the logic instructions in the memory 730 to execute a control method based on the grid-following ratio and the grid-building ratio, the method comprising: obtaining the system capacity and device capacity of the power system; wherein the system capacity refers to the sum of the rated capacities of various hub substations in the power system, and the device capacity refers to the installed capacity of the integrated grid-following function and the grid-building function equipment in the power system within a preset range; determining the short-circuit ratio according to the system capacity and the device capacity; determining the grid-following ratio and the grid-building ratio according to the short-circuit ratio; obtaining the three-phase voltage, three-phase current, DC side voltage and DC side reference voltage of the power system; and performing pulse width control according to the three-phase voltage, three-phase current, DC side voltage, DC side reference voltage, the grid-following ratio and the grid-building ratio.

[0089] In addition, the logic instructions in the above-mentioned memory 730 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0090] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the control method based on the grid-following ratio and the grid-building ratio provided by the above methods, and the method includes: obtaining the system capacity and device capacity of the power system; wherein the system capacity refers to the sum of the rated capacities of various hub substations in the power system, and the device capacity refers to the installed capacity of the power system's integrated grid-following function and grid-building function equipment within a preset range; determining the short-circuit ratio according to the system capacity and the device capacity; determining the grid-following ratio and the grid-building ratio according to the short-circuit ratio; obtaining the three-phase voltage, three-phase current, DC side voltage and DC side reference voltage of the power system; and performing pulse width control according to the three-phase voltage, three-phase current, DC side voltage, DC side reference voltage, grid-following ratio and grid-building ratio.

[0091] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the control method based on the grid-following ratio and the grid-forming ratio provided by the above-mentioned methods, the method comprising: obtaining the system capacity and device capacity of the power system; wherein the system capacity refers to the sum of the rated capacities of various hub substations in the power system, and the device capacity refers to the installed capacity of the power system's integrated grid-following function and grid-forming function equipment within a preset range; determining the short-circuit ratio according to the system capacity and the device capacity; determining the grid-following ratio and the grid-forming ratio according to the short-circuit ratio; obtaining the three-phase voltage, three-phase current, DC side voltage and DC side reference voltage of the power system; and performing pulse width control according to the three-phase voltage, three-phase current, DC side voltage, DC side reference voltage, grid-following ratio and grid-forming ratio.

[0092] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0093] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method based on network following ratio and network building ratio, characterized in that: include: Obtain the system capacity and device capacity of the power system; wherein the system capacity refers to the sum of the rated capacities of various hub substations in the power system, and the device capacity refers to the installed capacity of the integrated network-following function and network-building function equipment of the power system within a preset range; Determining a short circuit ratio according to the system capacity and the device capacity; Determine the network following ratio and network building ratio according to the short circuit ratio; Obtaining the three-phase voltage, three-phase current, DC side voltage and DC side reference voltage of the power system; Pulse width control is performed according to the three-phase voltage, the three-phase current, the DC side voltage, the DC side reference voltage, the grid-following ratio and the grid-forming ratio.

2. The control method based on the network following ratio and the network building ratio according to claim 1 is characterized in that: Determining the short-circuit ratio according to the system capacity and the device capacity includes: The short circuit ratio is determined according to a ratio of the system capacity to the device capacity.

3. The control method based on the network following ratio and the network building ratio according to claim 1 is characterized in that: The determining of the network following ratio and the network building ratio according to the short circuit ratio includes: Determine the corresponding relationship between the short-circuit ratio of the power grid and the target network construction ratio and the target network connection ratio; Based on the corresponding relationship, the network following ratio and the network building ratio corresponding to the short circuit ratio are obtained.

4. The control method based on the network following ratio and the network building ratio according to claim 3 is characterized in that: The determining of the correspondence between the short-circuit ratio of the power grid and the target network construction ratio and the target network following ratio includes: Under the specific short-circuit ratio of the power grid, the initial grid-following ratio and the initial grid-forming ratio of the power grid short-circuit ratio are simulated to obtain the initial grid-following ratio, the initial grid-forming ratio, the limit cut-off angle and the power amplitude value corresponding to the substation in the power system; wherein the initial grid-following ratio and the initial grid-forming ratio are both at least one; Fitting the initial network following ratio, the initial network building ratio, the limit resection angle and the power amplitude value to obtain a target relationship; Determining a cost function according to the target relationship; The cost function is solved to obtain the target grid-following ratio and the target grid-forming ratio corresponding to the grid short-circuit ratio, and a corresponding relationship is determined based on the grid short-circuit ratio, the target grid-following ratio and the target grid-forming ratio.

5. The control method based on the network following ratio and the network building ratio according to claim 4 is characterized in that: The step of determining a cost function according to the target relational expression comprises: Determine, according to the target relationship, a first weight corresponding to the limit resection angle and a second weight determined by the power amplitude value; A cost function is determined according to the first weight and the second weight.

6. The control method based on the network following ratio and the network building ratio according to any one of claims 1 to 5, characterized in that: The pulse width control is performed according to the three-phase voltage, the three-phase current, the DC side voltage, the DC side reference voltage, the grid-following ratio and the grid-forming ratio, including: Determine the internal potential phase angle and the internal potential amplitude according to the three-phase voltage, the three-phase current, the DC side voltage, the DC side reference voltage, the grid-following ratio and the grid-forming ratio; Determining a three-phase modulation voltage according to the internal potential phase angle and the internal potential amplitude; Pulse width control is performed according to the three-phase modulation voltage.

7. The control method based on the network following ratio and the network building ratio according to claim 6 is characterized in that: The determining of the internal potential phase angle and the internal potential amplitude according to the three-phase voltage, the three-phase current, the DC side voltage, the DC side reference voltage, the grid-following ratio and the grid-forming ratio comprises: Determine a two-phase voltage and a two-phase current according to the three-phase voltage and the three-phase current; wherein the two-phase voltage includes a first voltage and a second voltage; Determining a grid-following angular frequency according to the first voltage and the grid-following ratio; Determine a reactive power actual value and an active power actual value according to the first voltage, the second voltage and the two-phase current; Determining the internal potential amplitude according to the reactive power actual value; Determining a network angular frequency according to the DC side voltage, the DC side reference voltage, the actual value of active power and the network ratio; The internal potential phase angle is determined according to the grid-following angular frequency, the grid-building angular frequency and an angular frequency reference value.

8. A control device based on the network following ratio and network building ratio, characterized in that: include: The first acquisition module is used to acquire the system capacity and device capacity of the power system; wherein the system capacity refers to the sum of the rated capacities of various hub substations in the power system, and the device capacity refers to the installed capacity of the integrated network-following function and network-building function equipment of the power system within a preset range; A first determination module, configured to determine a short circuit ratio according to the system capacity and the device capacity; A second determination module is used to determine a network following ratio and a network building ratio according to the short circuit ratio; A second acquisition module is used to acquire the three-phase voltage, three-phase current, DC side voltage and DC side reference voltage of the power system; A width control module is used to perform pulse width control according to the three-phase voltage, the three-phase current, the DC side voltage, the DC side reference voltage, the grid-following ratio and the grid-forming ratio.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the control method based on the network following ratio and the network building ratio as described in any one of claims 1 to 7 is implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the control method based on the network following ratio and the network building ratio as described in any one of claims 1 to 7 is implemented.

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