Topology, control method, device and terminal of hybrid power flow controller

Abstract

The present invention provides a topology, control method, device, and terminal for a hybrid power flow controller. The topology includes a PST and an UPFC; the excitation transformer in the PST and the excitation transformer in the UPFC are configured as the same excitation transformer; the secondary winding of each phase of the excitation transformer includes a first winding and a second winding, the active end of the first winding of phase A is connected to the input end of the secondary winding of phase B of the series transformer in the PST; the active end of the first winding of phase B is connected to the input end of the secondary winding of phase C of the series transformer in the PST; the active end of the first winding of phase C is connected to the input end of the secondary winding of phase A of the series transformer in the PST; the fixed ends of the first winding of phase A, the winding of phase B, and the first winding of phase C are all grounded; and the two ends of the second winding of phase A, phase B, and phase C are respectively connected to the parallel side of the UPFC of the corresponding phase. The present invention can improve the accuracy of line power flow regulation while further reducing construction costs.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a topological structure, a control method, a device and a terminal for hybrid power flow control. Background Art

[0002] As power grids expand, their safety, stability, and economical operation are gaining increasing attention. In particular, the safety, reliability, and economical operation of transmission networks are receiving increasing attention. To ensure the safe operation of transmission networks, existing technologies typically employ unified power flow controllers (UPFCs) or phase-shifting transformers (PSTs) to regulate power flow on power lines.

[0003] UPFCs control power flow by injecting a continuously controllable voltage into transmission lines, both in phase and amplitude. This significantly increases the system's transmission capacity without changing the network structure, but their high cost makes them difficult to install on a large scale in the grid.

[0004] A PST is a new type of transformer used to regulate power flow in high-voltage transmission systems. By adjusting the phase angle difference before and after the phase shift, the phase-shifting transformer alters the current in the parallel branches, thereby controlling line power flow and improving power system stability. However, due to the limited number of tap positions available, line power flow regulation can only be performed based on the tap position, resulting in regulation accuracy often failing to meet expectations.

[0005] It can be seen that the existing technology cannot take into account both economic cost and regulation accuracy when regulating line current. Summary of the Invention

[0006] The embodiments of the present invention provide a topological structure, a control method, an apparatus and a terminal for hybrid power flow control to solve the problem in the prior art that it is impossible to take both economic cost and regulation accuracy into account when regulating line power flow.

[0007] In a first aspect, an embodiment of the present invention provides a topology structure of a hybrid power flow controller, including:

[0008] PST and UPFC;

[0009] The excitation transformer in the PST and the excitation transformer in the UPFC are configured as the same excitation transformer;

[0010] The secondary winding of each phase of the excitation transformer includes a first winding and a second winding, and the active end of the first winding of phase A is connected to the input end of the secondary winding of phase B of the series transformer in the PST;

[0011] The active end of the first winding of phase B is connected to the input end of the secondary winding of phase C of the series transformer in the PST;

[0012] The active end of the first winding of phase C is connected to the input end of the secondary winding of phase A of the series transformer in the PST;

[0013] The fixed ends of the first winding of phase A, the first winding of phase B, and the first winding of phase C are all grounded;

[0014] Both ends of the second winding of phase A, the second winding of phase B, and the second winding of phase C are respectively connected to the parallel side of the UPFC of the corresponding phase.

[0015] In a second aspect, an embodiment of the present invention provides a control method for a hybrid power flow controller, including:

[0016] Collect the line power flow under the current state of the busbar, and calculate the power deviation based on the collected results and the preset expected power;

[0017] respectively determining a magnitude relationship between the power deviation and a first preset value and a second preset value, and performing no compensation when the power deviation is less than or equal to the first preset value;

[0018] When the power deviation is greater than the first preset value and less than or equal to the second preset value, switching on the UPFC for compensation;

[0019] When the power deviation is greater than the second preset value, the PST is switched on for primary compensation, and after the primary compensation is completed, the UPFC is switched on for secondary compensation;

[0020] After the compensation is completed, jump to the step of "collecting the line flow of the bus in the current state, and calculating the power deviation based on the collection results and the preset expected power", re-collect the bus line flow in the current state, and execute subsequent steps until the power deviation is less than or equal to the first preset value.

[0021] In a possible implementation, when the power deviation is greater than the second preset value, switching the PST for primary compensation, and after the primary compensation is completed, switching the UPFC for secondary compensation, including:

[0022] Determining the tap position of the PST and the polarity of the transformer according to the power deviation;

[0023] According to the tap position and transformer polarity, switching the PST for primary compensation;

[0024] After the primary compensation is completed, determining the primary compensation voltage output by the PST, and calculating the secondary compensation voltage required to be provided by the UPFC based on the primary compensation voltage of the PST;

[0025] The UPFC is controlled to perform secondary compensation according to the secondary compensation voltage.

[0026] In a possible implementation, after calculating the power deviation according to the acquisition result and the preset expected power, the method further includes:

[0027] Obtaining line parameters in an initial state, and estimating a predicted compensation voltage based on the line parameters;

[0028] The power deviation is input into the PI controller to dynamically calculate the compensation voltage deviation in real time;

[0029] Calculating the secondary compensation voltage required to be provided by the UPFC according to the primary compensation voltage of the PST includes:

[0030] Obtaining a current compensation voltage deviation of the PI controller, and calculating an actually required compensation voltage based on the expected compensation voltage and the compensation voltage deviation;

[0031] The secondary compensation voltage required to be provided by the UPFC is calculated according to the actually required compensation voltage and the primary compensation voltage.

[0032] In one possible implementation, estimating the expected compensation voltage according to the line parameters includes:

[0033] according to estimating the expected compensation voltage;

[0034] Among them, U dse Indicates the expected active compensation voltage, U qse Indicates the expected reactive compensation voltage, P Lref Indicates the preset active expected power, Q Lref Indicates the preset reactive power expectation, X L Represents the line reactance, R L Indicates line resistance, ΔU ds Indicates the transverse voltage difference between the sending and receiving ends of the line, ΔU qs Indicates the longitudinal voltage difference between the sending and receiving ends of the line.

[0035] In a possible implementation, the calculating the actually required compensation voltage according to the estimated compensation voltage and the compensation voltage deviation includes:

[0036] Calculating the sum of the estimated compensation voltage and the compensation voltage deviation to determine the sum as the actually required compensation voltage;

[0037] The calculating the secondary compensation voltage required to be provided by the UPFC according to the actually required compensation voltage and the primary compensation voltage includes:

[0038] The difference between the actually required compensation voltage and the primary compensation voltage is calculated to determine the secondary compensation voltage required to be provided by the UPFC.

[0039] In a possible implementation, after determining the tap position of the PST and the polarity of the transformer according to the power deviation, the method further includes:

[0040] After the delay processing of the preset time, the PST is switched on and off according to the tap position and transformer polarity for compensation.

[0041] In a third aspect, an embodiment of the present invention provides a control device for a hybrid power flow controller, comprising:

[0042] The calculation module is used to collect the line power flow under the current state of the bus, and calculate the power deviation based on the collected results and the preset expected power;

[0043] a judgment execution module, configured to respectively judge the magnitude relationship between the power deviation and a first preset value and a second preset value, and not perform compensation when the power deviation is less than or equal to the first preset value;

[0044] The judgment execution module is further configured to switch on the UPFC for compensation when the power deviation is greater than the first preset value and less than or equal to the second preset value;

[0045] The judgment execution module is further configured to, when the power deviation is greater than the second preset value, switch on the PST for primary compensation, and after the primary compensation is completed, switch on the UPFC for secondary compensation;

[0046] The jump module is used to jump to the calculation module for execution after the compensation is completed.

[0047] In a fourth aspect, an embodiment of the present invention provides a terminal comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the method described in the first aspect or any possible implementation of the first aspect are implemented.

[0048] In a fifth aspect, an embodiment of the present invention provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the steps of the method described in the first aspect or any possible implementation of the first aspect.

[0049] Embodiments of the present invention provide a topology, control method, device, and terminal for a hybrid power flow controller. The topology of the hybrid power flow controller includes a power transformer (PST) and a power supply transformer (UPFC). The secondary winding of each phase of the excitation transformer includes a first winding and a second winding. The active end of the first winding of phase A is connected to the input end of the secondary winding of phase B of the series transformer in the PST; the active end of the first winding of phase B is connected to the input end of the secondary winding of phase C of the series transformer in the PST; and the active end of the first winding of phase C is connected to the input end of the secondary winding of phase A of the series transformer in the PST. The fixed ends of the first winding of phase A, the first winding of phase B, and the first winding of phase C are all grounded. The second windings of phase A, phase B, and phase C are each connected to the parallel side of the UPFC of the corresponding phase. In the hybrid power flow controller topology, the PST and UPFC share the primary winding of the same excitation transformer, ensuring not only an electrical connection but also an electromagnetic connection between the PST and UPFC, resulting in a more compact structure. At the same time, the use of small-capacity UPFC combined with large-capacity PST can improve the regulation accuracy on the basis of regulating line currents over a large range and further reduce construction costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, 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 only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0051] Figure 1 1 is a schematic diagram of the topological structure of a hybrid power flow controller provided by an embodiment of the present invention;

[0052] Figure 2 This is a flow chart of an implementation method of a hybrid power flow controller provided by one embodiment of the present invention;

[0053] Figure 3 is a flow chart of an implementation method of a hybrid power flow controller provided by another embodiment of the present invention;

[0054] Figure 4 This is a control block diagram of a control method for a hybrid power flow controller provided by one embodiment of the present invention;

[0055] Figure 5 This is a schematic diagram of a two-terminal network system of a simulation example provided by an embodiment of the present invention.

[0056] Figure 6 is a schematic diagram of simulation results of a simulation example provided by one embodiment of the present invention;

[0057] Figure 7 1 is a schematic structural diagram of a control device of a hybrid power flow controller provided by one embodiment of the present invention;

[0058] Figure 8 is a schematic diagram of a terminal provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0059] In the following description, specific details such as particular system structures and techniques are provided for purposes of illustration, not limitation, to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0060] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific embodiments will be described below with reference to the accompanying drawings.

[0061] Figure 1 A schematic diagram of the topology of a hybrid power flow controller (HPFC) provided in an embodiment of the present invention is described in detail as follows:

[0062] The topology of the hybrid power flow controller includes: PST1 and UPFC2.

[0063] The excitation transformer in PST1 and the excitation transformer in UPFC2 are set to be the same excitation transformer 11;

[0064] The secondary winding 111 of each phase of the excitation transformer 11 includes a first winding 1111 and a second winding 1112 , and the active end of the first winding 1111 of phase A is connected to the input end of the secondary winding 121 of phase B of the series transformer 12 in the PST;

[0065] The active end of the first winding 1111 of phase B is connected to the input end of the secondary winding 121 of phase C of the series transformer 12 in the PST;

[0066] The active end of the first winding 1111 of phase C is connected to the input end of the secondary winding 121 of phase A of the series transformer 12 in the PST;

[0067] The fixed ends of the first winding 1111 of phase A, the first winding 1111 of phase B, and the first winding 1111 of phase C are all grounded;

[0068] Two ends of the second winding 1112 of phase A, the second winding 1112 of phase B, and the second winding 1112 of phase C are respectively connected to the UPFC parallel side 221 of the corresponding phase.

[0069] The input end of the primary winding 112 of each phase of the excitation transformer 11 is connected to the center tap of the primary winding 122 of the corresponding phase of the series transformer 12 in the PST, and the output end of the primary winding 112 of each phase of the excitation transformer 11 is grounded.

[0070] The primary winding 122 of each phase of the series transformer 12 in the PST includes a third winding 1221 and a fourth winding 1222 connected in series. The connection point between the third winding 1221 and the fourth winding 1222 is the center tap. The input of the third winding 1221 is connected to the output of the corresponding phase of the power grid bus, and the output of the fourth winding 1222 is connected to the input of the primary winding 2221 of the series-side transformer 222 of the corresponding phase of the UPFC2.

[0071] The input end of the secondary winding 121 of phase A of the series transformer 12 in the PST is also connected to the output end of the secondary winding 121 of phase C of the series transformer 12 in the PST, and the output end of the secondary winding 121 of phase A of the series transformer 12 in the PST is connected to the input end of the secondary winding 121 of phase B of the series transformer 12 in the PST.

[0072] The output end of the secondary winding 121 of the B-phase of the series transformer 12 in the PST is connected to the input end of the secondary winding 121 of the C-phase of the series transformer 12 in the PST.

[0073] The output end of the primary side winding 2221 of the series side transformer 222 of the corresponding phase of UPFC2 is connected to the input end of the corresponding phase of the user-side bus.

[0074] An embodiment of the present invention provides a hybrid power flow controller topology. By placing the PST's tap (i.e., the aforementioned first winding) and the UPFC's parallel winding (i.e., the aforementioned second winding) on ​​the secondary side of the excitation transformer, the PST and UPFC share the same primary winding of the excitation transformer. This topology establishes not only an electrical connection between the PST and UPFC, but also an electromagnetic connection, resulting in a more compact structure. Furthermore, combining a small-capacity UPFC with a large-capacity PST improves regulation accuracy while reducing construction costs while regulating line power flow over a wide range.

[0075] On the other hand, by adopting the above-mentioned topological structure of hybrid power flow control, an embodiment of the present invention further provides a control method of a hybrid power flow controller.

[0076] Figure 2 The following is a flowchart of a control method for a hybrid power flow controller according to an embodiment of the present invention.

[0077] Step 201: collecting the line power flow in the current state of the bus, and calculating the power deviation based on the collected results and the preset expected power;

[0078] By collecting the instantaneous voltage and instantaneous current of the bus in the current state, the instantaneous power in the current state can be calculated.

[0079] To facilitate analysis, the collected instantaneous voltage and instantaneous current of each phase in the bus can be converted into the dq coordinate system for calculation and analysis.

[0080] It is important to note that to ensure the accuracy of subsequent calculations and analysis, the collected instantaneous voltage and current must be low-pass filtered. Low-pass filtering can extract the DC component in the instantaneous voltage and current, effectively reducing errors caused by other harmonics.

[0081] Specifically, according to Calculate active voltage and reactive voltage;

[0082] Among them, U ds Indicates active voltage, U qs Represents reactive voltage, C 32 represents the conversion factor, and U sa Indicates the instantaneous voltage of phase A in the busbar, U sb Indicates the instantaneous voltage of phase B in the busbar, U sc Indicates the instantaneous voltage of phase C in the bus.

[0083] according to Calculate active current and reactive current;

[0084] Among them, I ds Indicates active current, I qs Represents reactive current, I sa Indicates the instantaneous current of phase A in the bus, I sb Indicates the instantaneous current of phase B in the bus, I sc Indicates the instantaneous current of phase C in the bus.

[0085] according to Calculate active power and reactive power;

[0086] Among them, P r Indicates active power, Q r Represents reactive power, C pq Indicates the power factor.

[0087] The active power and reactive power of the bus in the current state can be obtained according to the above formula. The difference between the preset expected power and the active power and reactive power in the current state is further calculated to obtain the power deviation.

[0088] Specifically, according to Calculate the power deviation.

[0089] Among them, ΔP represents the active power deviation, P Lref Indicates the preset active power expectation, ΔQ indicates the reactive power deviation, Q Lref Indicates the preset reactive expected power.

[0090] Optional, see Figure 3 and Figure 4 , after step 201, further comprising:

[0091] Step 204: obtaining line parameters in an initial state and estimating an expected compensation voltage based on the line parameters;

[0092] Further optional, according to Estimate the expected compensation voltage;

[0093] Among them, U dse Indicates the expected active compensation voltage, U qse Indicates the expected reactive compensation voltage, P Lref Indicates the preset active expected power, Q Lref Indicates the preset reactive power expectation, X L Represents the line reactance, R L Indicates line resistance, ΔU ds Indicates the transverse voltage difference between the sending and receiving ends of the line, ΔU qs Indicates the longitudinal voltage difference between the sending and receiving ends of the line.

[0094] By estimating the expected compensation voltage in advance, the burden of the PI controller can be reduced, so that the hybrid power flow controller can produce a smaller overshoot during the control and regulation process, which is beneficial to the operation of the PST.

[0095] Step 205: Input the power deviation into the PI controller to dynamically calculate the compensation voltage deviation in real time.

[0096] It should be noted that the power deviation (including active power deviation and reactive power deviation) also needs to be low-pass filtered before being input into the PI controller in order to extract the DC component in the power deviation and effectively reduce the error caused by other harmonics.

[0097] Since the expected compensation voltage is obtained through estimation and has a certain deviation, a PI controller is introduced. The PI controller can dynamically calculate the compensation voltage deviation in real time based on the current power deviation to ensure the accuracy of subsequent power flow regulation.

[0098] Step 202, determining the magnitude relationship between the power deviation and the first preset value and the second preset value, and when the power deviation is less than or equal to the first preset value, no compensation is performed;

[0099] The first preset value is set by the user according to an acceptable error range. When the active power deviation is less than or equal to the first preset value, it is determined that the current active power deviation is within the allowable error range and no compensation operation is performed.

[0100] It should be noted that when the hybrid power flow controller compensates for the line power flow of the bus, active compensation is mainly used as the main compensation method. Therefore, when determining whether to perform the compensation operation, it is determined based on the size relationship between the active power deviation and the first preset value and the second preset value.

[0101] When the power deviation is greater than a first preset value and less than or equal to a second preset value, switching on the UPFC for compensation;

[0102] The second preset value here needs to be determined according to the average adjustment power of the PST tap. For example, the second preset value can be set to the average adjustment power P of the PST tap. PST When the active power deviation is less than half of the average power regulation of the PST tap (ie, ), switching on PST will undoubtedly increase the active power deviation. Therefore, PST is kept inactive and UPFC is used for compensation.

[0103] When the power deviation is greater than the second preset value, the PST is switched on for primary compensation. After the primary compensation is completed, the UPFC is switched on for secondary compensation.

[0104] Optionally, when the power deviation is greater than a second preset value, the PST is switched on for primary compensation. After the primary compensation is completed, the UPFC is switched on for secondary compensation, including:

[0105] Step 221, determining the tap position of the PST and the polarity of the transformer according to the power deviation;

[0106] Specifically, the tap position of the PST is determined according to the active power deviation and the average power adjusted by the tap positions of the PST, including: calculating a multiple value between the active power deviation and the average power adjusted by the tap positions of the PST, and selecting the tap position of the PST according to the multiple value. If the active power deviation and the average power of the PST tap are not an integer multiple, rounding is performed. For example: when , the third gear of the PST tap is selected.

[0107] Determine the transformer polarity based on the positive or negative active power deviation, including:

[0108] When ΔP<0, that is, when the active power needs to be reduced, the PST is determined to be negative polarity; when ΔP>0, that is, when the active power needs to be increased, the PST is determined to be positive polarity.

[0109] Step 222: Switching the PST to perform primary compensation according to the tap position and transformer polarity.

[0110] After determining the tap position and transformer polarity, the tap action of the PST is controlled according to the tap position and transformer polarity to perform a compensation.

[0111] Optionally, after step 221, the following steps may be further included:

[0112] Step 225: After the delay processing of the preset time, compensation is performed again according to the tap position and the transformer polarity switching PST.

[0113] To avoid excessive overshoot or a situation where the voltage deviation before and after adjustment is almost the same, the PST tap is controlled after a preset delay. Delayed switching effectively prevents erroneous PST tap operation caused by power flow fluctuations.

[0114] As a better implementation method, delay processing should be performed before and after the tap action of the PST to ensure the stable operation of the hybrid power flow controller.

[0115] Step 223: After the primary compensation is completed, determine the primary compensation voltage output by the PST, and calculate the secondary compensation voltage required by the UPFC based on the primary compensation voltage of the PST;

[0116] Further optionally, step 223 includes:

[0117] Obtain the current compensation voltage deviation of the PI controller, and calculate the actual required compensation voltage based on the expected compensation voltage and the compensation voltage deviation;

[0118] It should be noted that, see Figure 4 Since the power deviation input to the PI controller includes active power deviation and reactive power deviation, the compensation voltage deviation output by the PI controller in real time calculation includes active compensation voltage deviation and reactive voltage compensation deviation.

[0119] Among them, the active compensation voltage deviation is used to calculate the actual required compensation voltage in combination with the active predicted compensation voltage to obtain the secondary compensation voltage, and the reactive compensation voltage deviation is used to be input into the UPFC together with the reactive predicted compensation voltage for reactive compensation.

[0120] Specifically, the sum of the expected compensation voltage and the compensation voltage deviation is calculated and determined as the actually required compensation voltage.

[0121] When calculating the actually required compensation voltage, the expected compensation voltage here specifically refers to the active expected compensation voltage, and the compensation voltage deviation here specifically refers to the active compensation voltage deviation.

[0122] Calculate the secondary compensation voltage that UPFC needs to provide based on the actual required compensation voltage and the primary compensation voltage;

[0123] Specifically, the difference between the actually required compensation voltage and the primary compensation voltage is calculated and determined as the secondary compensation voltage that the UPFC needs to provide.

[0124] Step 224 : Control the UPFC to perform secondary compensation according to the secondary compensation voltage.

[0125] The calculated secondary compensation voltage is input to the UPFC, which then performs secondary compensation based on the secondary compensation voltage. Because the PST tap is delayed, tap operation is delayed. Therefore, the secondary compensation voltage input to the UPFC needs to be limited to prevent excessive values ​​that could affect UPFC operation.

[0126] See also Figure 4 In order to ensure the stable operation of UPFC, when the reactive compensation voltage deviation and the reactive compensation voltage are input into UPFC together, corresponding limiting processing is also required.

[0127] After the PST completes the primary compensation, the UPFC continues to complete the secondary compensation. At the same time, the UPFC also completes the reactive power compensation of the entire system based on the reactive power compensation voltage deviation and the reactive power expected compensation voltage (the PST does not participate in reactive power compensation). At this point, the current compensation operation is completed.

[0128] Step 203: After the compensation is completed, jump to the step of "collecting the line flow of the bus in the current state, and calculating the power deviation based on the collection results and the preset expected power", re-collect the bus line flow in the current state, and execute subsequent steps until the power deviation is less than or equal to the first preset value.

[0129] The feasibility of this control method is illustrated below with a simulation example:

[0130] Build as Figure 5 The two-terminal network system shown in the figure has a voltage of 525∠0° at the sending end, a voltage of 500∠-10° at the receiving end, an internal resistance of the power supply of 0.5+j6.28Ω, and an equivalent line impedance of 2.5+j35.48Ω.

[0131] Therefore, the calculated line power flow is as follows:

[0132] The line current is:

[0133]

[0134] The output power of the sending end power supply is:

[0135]

[0136] It is now planned to install a hybrid power flow controller to increase the active power to 1300MVA. The parameters of the hybrid power flow controller are shown in Table 1.

[0137] parameter PST UPFC Series transformer rated voltage / kV 525 / 220 3.5 / 3.5 Series transformer rated capacity / MVA 4.8 0.3 Rated voltage of parallel transformer / kV 525 / 220 / 5.35 525 / 220 / 5.35 Parallel transformer rated capacity / MVA 4.8 4.8 DC voltage / kV 10.12 DC capacitance / mF 0.8 AC inductance / mH 0.36

[0138] Table 1

[0139] The simulation results are as follows Figure 6 As shown, at 0.25 seconds, the PST takes action, and then at 0.7 seconds, the UPFC compensates for the remaining amount, completing the adjustment of the desired power flow, and reliably completing the adjustment of the initial power flow from 960MVA to the desired 1300MVA.

[0140] The embodiment of the present invention collects the line flow in the current state of the bus, and calculates the power deviation according to the collected result and the preset expected power; the magnitude relationship between the power deviation and the first preset value and the second preset value is respectively determined, and when the power deviation is less than or equal to the first preset value, no compensation is performed; when the power deviation is greater than the first preset value and less than or equal to the second preset value, the UPFC is switched on for compensation; when the power deviation is greater than the second preset value, the PST is switched on for primary compensation, and after the primary compensation is completed, the UPFC is switched on for secondary compensation; after the compensation is completed, the process jumps to the step of "collecting the line flow in the current state of the bus, and calculating the power deviation according to the collected result and the preset expected power", re-collecting the bus line flow in the current state, and executing subsequent steps until the power deviation is less than or equal to the first preset value, thereby achieving the technical effect of accurately controlling the line flow in a wide range while reducing construction costs.

[0141] Furthermore, the UPFC is controlled to perform secondary compensation by combining the power outer loop control PST tap action with the PI controller, which improves the stability and response speed of the hybrid power flow controller. At the same time, the estimated compensation voltage is combined with the highly stable PI controller to achieve the purpose of flexible and stable control of the line power flow.

[0142] Furthermore, estimating the predicted compensation voltage can reduce the burden on the PI controller, resulting in a smaller overshoot during the hybrid power flow controller's regulation process, facilitating PST operation and maintenance. Furthermore, delayed switching effectively prevents malfunctions of the hybrid power flow controller during transient conditions and improves its power flow regulation accuracy.

[0143] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0144] The following are device embodiments of the present invention. For details not fully described therein, reference may be made to the corresponding method embodiments described above.

[0145] Figure 7 A schematic diagram of the structure of a control device of a hybrid power flow controller provided by an embodiment of the present invention is shown. For ease of explanation, only the parts related to the embodiment of the present invention are shown, which are described in detail as follows:

[0146] like Figure 7 As shown, the control device 7 of the hybrid power flow controller includes: a calculation module 71 , a judgment and execution module 72 and a jump module 73 .

[0147] The calculation module 71 is used to collect the line power flow under the current state of the bus, and calculate the power deviation based on the collected results and the preset expected power;

[0148] Specifically, the calculation module 71 is used to calculate the Calculate active voltage and reactive voltage;

[0149] according to Calculate active current and reactive current;

[0150] according to Calculate active power and reactive power;

[0151] According to the above formula, the active power and reactive power of the bus in the current state can be obtained.

[0152] Furthermore, the calculation module 71 is further configured to calculate the difference between the preset expected power and the active power and reactive power in the current state to obtain a power deviation.

[0153] Specifically, the calculation module 71 is used to calculate the Calculate the power deviation.

[0154] After obtaining the power deviation, the calculation module 71 is further configured to obtain line parameters in an initial state and estimate the expected compensation voltage based on the line parameters.

[0155] In a possible implementation, the calculation module 71 is configured to: Estimate the expected compensation voltage;

[0156] By estimating the expected compensation voltage in advance, the burden of the PI controller can be reduced, so that the hybrid power flow controller can produce a smaller overshoot during the control and regulation process, which is beneficial to the operation of the PST.

[0157] The calculation module 71 is further used to input the power deviation into the PI controller and dynamically calculate the compensation voltage deviation in real time.

[0158] Since the expected compensation voltage is obtained through estimation and has a certain deviation, a PI controller is introduced. The PI controller can dynamically calculate the compensation voltage deviation in real time based on the current power deviation to ensure the accuracy of subsequent power flow regulation.

[0159] a judgment execution module 72 for respectively judging the magnitude relationship between the power deviation and the first preset value and the second preset value, and performing no compensation when the power deviation is less than or equal to the first preset value;

[0160] It should be noted that when the hybrid power flow controller compensates for the line power flow of the bus, it mainly uses active power compensation. Therefore, when determining whether to perform the compensation operation, it is determined based on the size relationship between the active power deviation and the first preset value and the second preset value.

[0161] The judgment execution module 72 is further configured to switch on the UPFC for compensation when the power deviation is greater than a first preset value and less than or equal to a second preset value;

[0162] The judgment execution module 72 is further configured to, when the power deviation is greater than a second preset value, switch the PST for primary compensation, and after the primary compensation is completed, switch the UPFC for secondary compensation;

[0163] In one possible implementation, the judgment execution module 72 is configured to determine the tap position of the PST and the transformer polarity according to the power deviation;

[0164] Specifically, the judgment execution module 72 is used to determine the tap position of the PST based on the active power deviation and the average tap adjustment power of the PST, including: calculating a multiple value between the active power deviation and the average tap adjustment power of the PST, and selecting the tap position of the PST based on the multiple value.

[0165] The judgment execution module 72 is used to determine the transformer polarity according to the positive or negative active power deviation, including: when ΔP<0, that is, when the active power needs to be reduced, the PST is determined to be negative polarity; when ΔP>0, that is, when the active power needs to be increased, the PST is determined to be positive polarity.

[0166] The judgment execution module 72 is also used to perform a delay process of a preset time;

[0167] The judgment execution module 72 is further configured to switch the PST on and off for compensation according to the tap position and transformer polarity after a preset time delay.

[0168] The judgment execution module 72 is used to determine the primary compensation voltage output by the PST after the primary compensation is completed, and calculate the secondary compensation voltage required to be provided by the UPFC based on the primary compensation voltage of the PST;

[0169] In a possible implementation, the judgment execution module 72 is configured to obtain a current compensation voltage deviation of the PI controller and calculate an actual required compensation voltage based on the expected compensation voltage and the compensation voltage deviation;

[0170] Specifically, the judgment execution module 72 is used to calculate the sum of the expected compensation voltage and the active compensation voltage deviation, and determine it as the actually required compensation voltage.

[0171] When calculating the actually required compensation voltage, the expected compensation voltage here specifically refers to the active expected compensation voltage, and the compensation voltage deviation here specifically refers to the active compensation voltage deviation.

[0172] The judgment execution module 72 is further used to calculate the secondary compensation voltage that the UPFC needs to provide based on the actual required compensation voltage and the primary compensation voltage;

[0173] Specifically, the difference between the actually required compensation voltage and the primary compensation voltage is calculated and determined as the secondary compensation voltage that the UPFC needs to provide.

[0174] The judgment execution module 72 is further configured to control the UPFC to perform secondary compensation according to the secondary compensation voltage.

[0175] Specifically, the judgment and execution module 72 is configured to input the calculated secondary compensation voltage into the UPFC, which then performs secondary active power compensation based on the secondary compensation voltage. Because the PST tap is delayed, tap operation is delayed. Therefore, the judgment and execution module 72 is also configured to limit the secondary compensation voltage input to the UPFC to prevent excessive values ​​from affecting UPFC operation.

[0176] In order to ensure the stable operation of UPFC, when the reactive compensation voltage deviation and the reactive compensation voltage are input into UPFC together, corresponding limiting processing is also required.

[0177] After the PST completes the primary compensation, the UPFC continues to complete the secondary compensation. At the same time, the UPFC also completes the reactive power compensation of the entire system based on the reactive power compensation voltage deviation and the reactive power expected compensation voltage (the PST does not participate in reactive power compensation). At this point, the current compensation operation is completed.

[0178] The jump module 73 is used to jump to the calculation module for execution after the compensation is completed.

[0179] In the embodiment of the present invention, a calculation module 71 is used to collect the line flow in the current state of the bus and calculate the power deviation based on the collected results and the preset expected power. A judgment and execution module 72 is used to respectively determine the magnitude relationship between the power deviation and a first preset value and a second preset value. When the power deviation is less than or equal to the first preset value, no compensation is performed. When the power deviation is greater than the first preset value and less than or equal to the second preset value, the UPFC is switched on for compensation. When the power deviation is greater than the second preset value, the PST is switched on for primary compensation. After the primary compensation is completed, the UPFC is switched on for secondary compensation. A jump module 73 is used to jump to the calculation module 71 after the compensation is completed. The calculation module 71 re-executes the step of "collecting the line flow in the current state of the bus and calculating the power deviation based on the collected results and the preset expected power". The calculation module 71 re-collects the bus line flow in the current state and executes subsequent steps until the power deviation is less than or equal to the first preset value. This can achieve the technical effect of accurately controlling the line flow over a large range while reducing construction costs.

[0180] Figure 8 Schematic diagram of a terminal provided by an embodiment of the present invention. Figure 8 As shown, the terminal 8 of this embodiment includes: a processor 80, a memory 81, and a computer program 82 stored in the memory 81 and executable on the processor 80. When the processor 80 executes the computer program 82, the steps of the control method embodiments of the hybrid power flow controller described above are implemented, such as Figure 2 Alternatively, when the processor 80 executes the computer program 82, the functions of the modules / units in the above-mentioned device embodiments are realized, for example, Figure 7 Functions of the modules / units 71 to 73 shown.

[0181] Exemplarily, the computer program 82 may be divided into one or more modules / units, which are stored in the memory 81 and executed by the processor 80 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program 82 in the terminal 8. For example, the computer program 82 may be divided into Figure 7 Modules / units 71 to 73 are shown.

[0182] The terminal 8 can be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The terminal 8 can include, but is not limited to, a processor 80 and a memory 81. Those skilled in the art will understand that Figure 8 It is only an example of terminal 8 and does not constitute a limitation on terminal 8. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the terminal may also include input and output devices, network access devices, buses, etc.

[0183] The processor 80 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0184] The memory 81 may be an internal storage unit of the terminal 8, such as a hard disk or memory of the terminal 8. The memory 81 may also be an external storage device of the terminal 8, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash memory card, etc. equipped on the terminal 8. Furthermore, the memory 81 may include both an internal storage unit of the terminal 8 and an external storage device. The memory 81 is used to store the computer program and other programs and data required by the terminal. The memory 81 may also be used to temporarily store data that has been output or is about to be output.

[0185] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0186] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0187] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0188] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For example, the division of the modules or units is merely a logical functional division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interface, indirect coupling or communication connection of devices or units, and can be electrical, mechanical, or other forms.

[0189] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0190] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0191] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, it can implement the steps of the above-mentioned control method embodiments of each hybrid power flow controller. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device that can carry the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practices in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practices, computer-readable media does not include electrical carrier signals and telecommunication signals.

[0192] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. 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. 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 various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A topology method of a hybrid power flow controller, using a topology structure of a hybrid power flow controller, characterized in that: The topology of the hybrid power flow controller includes: PST and UPFC; The excitation transformer in the PST and the excitation transformer in the UPFC are set to be the same excitation transformer; The secondary winding of each phase of the excitation transformer includes a first winding and a second winding, and the active end of the first winding of phase A is connected to the input end of the secondary winding of phase B of the series transformer in the PST; The active end of the first winding of phase B is connected to the input end of the secondary winding of phase C of the series transformer in the PST; the active end of the first winding of phase C is connected to the input end of the secondary winding of phase A of the series transformer in the PST; The fixed ends of the first winding of phase A, the first winding of phase B, and the first winding of phase C are all grounded; Both ends of the second winding of phase A, the second winding of phase B, and the second winding of phase C are connected to the parallel side of the UPFC of the corresponding phase respectively; The method comprises: Collect the line power flow under the current state of the busbar, and calculate the power deviation based on the collected results and the preset expected power; respectively determining a magnitude relationship between the power deviation and a first preset value and a second preset value, and performing no compensation when the power deviation is less than or equal to the first preset value; When the power deviation is greater than the first preset value and less than or equal to the second preset value, switching on the UPFC for compensation; When the power deviation is greater than the second preset value, the PST is switched on for primary compensation, and after the primary compensation is completed, the UPFC is switched on for secondary compensation; After the compensation is completed, jump to the step of "collecting the line flow of the bus in the current state, and calculating the power deviation based on the collection result and the preset expected power", re-collect the bus line flow in the current state, and execute subsequent steps until the power deviation is less than or equal to the first preset value.

2. The control method of the hybrid power flow controller according to claim 1, wherein: When the power deviation is greater than the second preset value, switching the PST for primary compensation, and after the primary compensation is completed, switching the UPFC for secondary compensation, including: Determining the tap position of the PST and the polarity of the transformer according to the power deviation; According to the tap position and transformer polarity, switching the PST for primary compensation; After the primary compensation is completed, determining the primary compensation voltage output by the PST, and calculating the secondary compensation voltage required to be provided by the UPFC based on the primary compensation voltage of the PST; The UPFC is controlled to perform secondary compensation according to the secondary compensation voltage.

3. The control method of the hybrid power flow controller according to claim 2, characterized in that: After calculating the power deviation according to the acquisition result and the preset expected power, the method further includes: Obtaining line parameters in an initial state, and estimating a predicted compensation voltage based on the line parameters; The power deviation is input into the PI controller to dynamically calculate the compensation voltage deviation in real time; Calculating the secondary compensation voltage required to be provided by the UPFC according to the primary compensation voltage of the PST includes: Obtaining a current compensation voltage deviation of the PI controller, and calculating an actually required compensation voltage based on the expected compensation voltage and the compensation voltage deviation; The secondary compensation voltage required to be provided by the UPFC is calculated according to the actually required compensation voltage and the primary compensation voltage.

4. The control method of the hybrid power flow controller according to claim 3, characterized in that: Estimating a predicted compensation voltage based on the line parameters, including: according to estimating the expected compensation voltage; Among them, U dse Indicates the expected active compensation voltage, U qse Indicates the expected reactive compensation voltage, P Lref Indicates the preset active expected power, Q Lref Indicates the preset reactive power expectation, X L Represents the line reactance, R L Indicates line resistance, ΔU ds Indicates the transverse voltage difference between the sending and receiving ends of the line, ΔU qs Indicates the longitudinal voltage difference between the sending and receiving ends of the line.

5. The control method of the hybrid power flow controller according to claim 3, wherein: The calculating the actual required compensation voltage according to the estimated compensation voltage and the compensation voltage deviation includes: Calculating the sum of the estimated compensation voltage and the compensation voltage deviation to determine the sum as the actually required compensation voltage; The calculating the secondary compensation voltage required to be provided by the UPFC according to the actually required compensation voltage and the primary compensation voltage includes: The difference between the actually required compensation voltage and the primary compensation voltage is calculated to determine the secondary compensation voltage required to be provided by the UPFC.

6. The control method of the hybrid power flow controller according to claim 2, wherein: After determining the tap position of the PST and the polarity of the transformer according to the power deviation, the method further includes: After the delay processing of the preset time, the PST is switched on and off according to the tap position and transformer polarity for compensation.

7. A control device for a hybrid power flow controller, characterized in that: include: The calculation module is used to collect the line power flow under the current state of the bus, and calculate the power deviation based on the collected results and the preset expected power; a judgment execution module, configured to respectively judge the magnitude relationship between the power deviation and a first preset value and a second preset value, and not perform compensation when the power deviation is less than or equal to the first preset value; The judgment execution module is further configured to switch on the UPFC for compensation when the power deviation is greater than the first preset value and less than or equal to the second preset value; The judgment execution module is further configured to, when the power deviation is greater than the second preset value, switch on the PST for primary compensation, and after the primary compensation is completed, switch on the UPFC for secondary compensation; The jump module is used to jump to the calculation module for execution after the compensation is completed.

8. A terminal comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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