A method and system for active voltage regulation of induction motor groups in a distribution station area

Abstract

This invention discloses a method and system for active voltage regulation of induction motor groups in a distribution substation. The method categorizes the induction motors within the substation according to their load characteristics and aggregates each type of motor. Based on the reactive power output of the infinite power supply in the substation, a voltage regulation objective function is determined. Using multiple preset constraints, the voltage regulation objective function is optimized and solved to obtain an optimized transformer tap. These preset constraints include voltage-power characteristic constraints for each type of motor group. Based on the optimized transformer tap, the tap position of the on-load tap-changing transformer is modulated. This invention optimizes the adjustment of the on-load tap-changing transformer tap according to the load conditions of the motor group, meeting the active and reactive power regulation needs of substations containing induction motor groups, achieving economical operation of substations containing induction motor groups, and providing important reference value for the formulation of voltage regulation strategies for distribution substations.

Description

Technical Field

[0001] This invention relates to the field of power distribution network control technology, specifically to a method and system for active voltage regulation of induction motor groups in a power distribution substation. Background Technology

[0002] The large-scale integration of new energy sources into new power systems leads to intermittent and fluctuating characteristics of the power grid, resulting in very limited regulation resources on the power source side. Therefore, to maintain stable grid operation, it is necessary to strengthen source-load interaction and enhance dynamic response on the load side. On-load tap changers (OLTCs) are crucial voltage regulation devices in distribution substations, automatically adjusting their turns ratio to maintain the voltage level on the load side while regulating load power, effectively reducing the regulation burden on the grid side. Three-phase induction motors are the main dynamic loads in power systems, and the rational regulation of load voltage in distribution networks containing induction motor groups is a key aspect of system power control. The load characteristics of distribution substations are an important factor affecting voltage-power regulation effects; however, previous studies on active voltage regulation using OLTCs in distribution substations often failed to consider the load characteristics of induction motor groups, thus having certain limitations. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the limitations of existing research on active voltage regulation of OLTC in distribution substations, which often does not take into account the load characteristics of induction motor groups. Thus, the present invention provides an active voltage regulation method and system for induction motor groups in distribution substations.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] In a first aspect, embodiments of the present invention provide an active voltage regulation method for a distribution substation induction motor group. The main circuit of the distribution substation includes: an infinite power supply, an on-load tap-changing transformer, and multiple induction motors. The infinite power supply simultaneously supplies power to multiple induction motors through the on-load tap-changing transformer. The method includes: classifying the induction motors in the substation according to their load characteristics and aggregating each type of motor; determining the voltage regulation objective function based on the reactive power that the infinite power supply in the substation can generate; optimizing the voltage regulation objective function using multiple preset constraints to obtain the optimal transformer tap, the preset constraints including the voltage-power characteristic constraints of each type of motor group; and modulating the tap position of the on-load tap-changing transformer based on the optimal transformer tap.

[0006] In one embodiment, the process of classifying induction motors within a distribution area according to load characteristics includes: calculating the input active power and reactive power of each motor within a preset voltage per-unit value range, or a preset load rate range, or a preset secondary torque coefficient range at different voltages, and obtaining voltage-voltage per-unit value curves, voltage-load rate curves, and voltage-secondary torque coefficient curves; determining the active critical load rate, reactive critical load rate, and critical torque coefficient based on the voltage-voltage per-unit value curves, voltage-load rate curves, and voltage-secondary torque coefficient curves; and classifying the induction motors within the distribution area according to the active critical load rate, reactive critical load rate, and critical torque coefficient.

[0007] In one embodiment, the process of determining the voltage regulation objective function based on the reactive power that the infinite power supply in the distribution area can generate includes: when the reactive power that the infinite power supply in the distribution area can generate is less than the reactive power margin, the minimum reactive power of the load is taken as the voltage regulation objective function; when the reactive power that the infinite power supply in the distribution area can generate is greater than or equal to the reactive power margin, the minimum active power of the load is taken as the voltage regulation objective function.

[0008] In one embodiment, when minimizing reactive power is used as the objective function for voltage regulation, the voltage-power characteristic constraints of the motor group for each type of motor are as follows:

[0009]

[0010] When the minimum active power of the load is taken as the objective function for voltage regulation, the voltage-power characteristic constraints of the motor group for each type of motor are as follows:

[0011]

[0012] Among them, P i|0.8<U<1.2 Q i|0.8<U<1.2 This represents the active and reactive power input to the i-th polymer motor when the voltage is between 0.8 and 1.2.

[0013] In one embodiment, the preset constraint conditions further include: load-side voltage constraint conditions;

[0014] The load-side voltage constraint is as follows:

[0015] U min <U<U max

[0016] Among them, U max U min These are the upper and lower limits of the load-side voltage, respectively, and U is the motor terminal voltage.

[0017] In one embodiment, the preset constraint conditions further include: load-side current constraint conditions;

[0018] The load-side current constraint condition is:

[0019] I min IM max

[0020] Among them, I IM I represents the total current in the transformer area. min The set minimum current value; I max This is the set maximum current value.

[0021] In one embodiment, the preset constraint conditions further include: transformer tap constraint conditions;

[0022] The transformer tap constraint conditions are:

[0023]

[0024] Where S represents the transformer tap, with a value ranging from -8 to +8; n step U represents the voltage adjustment amount per step of the transformer. N U is the rated voltage on the load side, and U is the motor terminal voltage.

[0025] Secondly, embodiments of the present invention provide an active voltage regulation system for a distribution substation induction motor group. The main circuit of the distribution substation includes: an infinite power supply, an on-load tap-changing transformer, and multiple induction motors. The infinite power supply simultaneously supplies power to multiple induction motors through the on-load tap-changing transformer. The system includes: a classification and aggregation module for classifying the induction motors in the substation according to their load characteristics and aggregating each type of motor; an objective function module for determining the voltage regulation objective function based on the reactive power that the infinite power supply in the substation can generate; an optimization solution module for optimizing the voltage regulation objective function using multiple preset constraints to obtain the optimal transformer tap, the preset constraints including the voltage-power characteristic constraints of the motor group for each type of motor; and an adjustment module for adjusting the tap position of the on-load tap-changing transformer based on the optimal transformer tap.

[0026] Thirdly, embodiments of the present invention provide a computer device, including: at least one processor, and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to cause the at least one processor to perform the active voltage regulation method for distribution substation induction motor groups according to the first aspect of the present invention.

[0027] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing computer instructions for causing a computer to execute the active voltage regulation method for a distribution substation induction motor group according to the first aspect of the present invention.

[0028] ​​The technical solution of this invention has the following advantages:

[0029] The present invention provides a method and system for active voltage regulation of induction motor groups in distribution substations. The method classifies the induction motors within the substation according to their load characteristics and aggregates each type of motor. Based on the reactive power output of the infinite power supply in the substation, a voltage regulation objective function is determined. Using multiple preset constraints, the voltage regulation objective function is optimized and solved to obtain an optimized transformer tap. These preset constraints include voltage-power characteristic constraints for each type of motor group. Based on the optimized transformer tap, the tap position of the on-load tap-changing transformer is modulated. This invention optimizes the adjustment of the on-load tap-changing transformer tap according to the load conditions of the motor group, meeting the active and reactive power regulation needs of substations containing motor groups, achieving economical operation of substations containing induction motor groups, and providing important reference value for the formulation of voltage regulation strategies for distribution substations. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the active voltage regulator for the induction motor group in the distribution substation and the main circuit of the distribution substation provided in an embodiment of the present invention;

[0032] Figure 2 A flowchart illustrating a specific example of the voltage regulation method provided in an embodiment of the present invention;

[0033] Figure 3 A schematic diagram illustrating the classification of transformer substation motor groups based on load type, load rate, and load torque coefficient, provided in an embodiment of the present invention.

[0034] Figure 4 A detailed flowchart of the voltage regulation method provided in this embodiment of the invention;

[0035] Figure 5 The voltage-active power regulation curve of the motor under constant power load provided in the embodiments of the present invention;

[0036] Figure 6 The voltage-reactive power regulation curve of the motor under constant power load provided in the embodiments of the present invention;

[0037] Figure 7 The voltage-reactive power regulation curve provided in this embodiment of the invention when the motor is driven by a fan or water pump load;

[0038] Figure 8 A composition diagram of a specific example of a voltage regulating system provided in an embodiment of the present invention;

[0039] Figure 9 This is a composition diagram of a specific example of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0040] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0044] Example 1

[0045] This invention provides an active voltage regulation method for a distribution substation induction motor group, such as... Figure 1 As shown, the main circuit of the distribution area includes: an infinite power supply, an on-load tap-changing transformer, and multiple induction motors. The infinite power supply simultaneously powers multiple induction motors through the on-load tap-changing transformer, as shown below. Figure 2 As shown, the method includes:

[0046] Step S11: Classify the induction motors in the transformer area according to their load characteristics and aggregate each type of motor.

[0047] Specifically, in this embodiment of the invention, an active voltage regulation strategy is specifically formulated based on the different load types of motors in the distribution substation. The motor groups in the substation are classified according to different load types and load rates, and each type of motor has the same voltage-power regulation characteristics. Secondly, each type of motor is aggregated into one motor to reduce model complexity.

[0048] Specifically, the process of classifying induction motors within the transformer substation according to load characteristics includes:

[0049] (1) Calculate the input active power and reactive power of each motor within the preset voltage per unit value range, or the preset load rate range, or the preset secondary torque coefficient range at different voltages, and obtain the voltage-voltage per unit value curve, voltage-load rate curve, and voltage-secondary torque coefficient curve.

[0050] Specifically, in this embodiment of the invention, the voltage-power regulation characteristics of the induction motor with constant power and the fan and water pump load in the distribution area are considered. The input active power and reactive power of each motor in the preset voltage per unit value range, or the preset load rate range, or the preset secondary torque coefficient range at different voltages are calculated using equations (1) to (5).

[0051]

[0052]

[0053]

[0054]

[0055] Z Σ,i =R Σ,i +jX Σ,i =R s,i +jX sl,i +(jX m,i ) / / (R r,i / s i +jX rl,i (5)

[0056] Where the subscript i represents the parameter of the i-th induction motor in the distribution area; T L,i Z represents the motor load torque; U represents the motor terminal voltage; Z represents the... Σ,i R Σ,i X Σ,i These are the total impedance, total resistance, and total reactance of the induction motor, respectively; X m,i X sl,i Xrl,i For motor excitation reactance, stator leakage reactance, and rotor leakage reactance; s i R is the motor slip rate. s,i R r,i For stator and rotor resistance; k i Motor load rate; A i P is the secondary load torque coefficient; i Q i Input active and reactive power to the motor.

[0057] Specifically, the per-unit voltage U of each motor in the distribution area is calculated using equations (1) to (5) within the range of (0.8, 1.2), and the load rate k is calculated accordingly. i Within the interval (0, 1) (constant power load condition) or the secondary torque coefficient A i Input active and reactive power within the (0,1) interval (for fan and pump loads).

[0058] (2) Based on the voltage-voltage per unit curve, voltage-load rate curve, and voltage-secondary torque coefficient curve, determine the active critical load rate, reactive critical load rate, and critical torque coefficient.

[0059] Specifically, based on the voltage-per-unit voltage curve and the voltage-load rate curve, the load rate k of each motor is determined. i The trend of input active power with voltage increase and decrease when (0, 1) is varied, and the critical active power load factor K is determined. P,i Make the load factor less than K P,i and greater than K P,i At that time, the active power exhibits different trends of increase and decrease as the voltage increases.

[0060] Specifically, based on the voltage-per-unit voltage curve and the voltage-load rate curve, the load rate k of each motor is determined. i The trend of input reactive power with voltage increase and decrease when (0, 1) is observed, and the critical reactive load factor K is determined. Q,i Make the load factor less than K Q,i and greater than K Q,i At that time, reactive power exhibits different trends of increase and decrease as voltage increases.

[0061] Specifically, based on the voltage-per-unit voltage curve and the voltage-secondary torque coefficient curve, the secondary torque coefficient A of each motor is determined. i The trend of input reactive power with voltage increase and decrease when (0, 1) is observed, and the critical torque coefficient A is determined. Q,i This makes the secondary torque coefficient less than K. Q,i and greater than K Q,i At that time, reactive power exhibits different trends of increase and decrease as voltage increases.

[0062] Specifically, the active power critical load factor K, which reflects the overall voltage-power regulation characteristics of the transformer area, is calculated. P Reactive power critical load factor K Q With critical torque coefficient A Q As shown in equations (6) to (8).

[0063]

[0064]

[0065]

[0066] In the formula, K P,i K Q,i A Q,i These represent the active critical load rate, reactive critical load rate, and critical torque coefficient of the i-th motor, respectively; M is the total number of motors in the distribution area.

[0067] (3) Classify the induction motors in the transformer area according to the active critical load rate, reactive critical load rate and critical torque coefficient.

[0068] Specifically, such as Figure 3 As shown, based on the actual load conditions of the generator group in the distribution area, the generators are divided into the following five categories:

[0069] 1) With a constant power load, and the load factor is within (0, K) P )Inside;

[0070] 2) With a constant power load, and the load factor is within (K) P K Q )Inside;

[0071] 3) With a constant power load, and the load factor is within (K) Q ,1) inside;

[0072] 4) Loads with fans or pumps, and where the secondary torque coefficient is within (0, A) Q )Inside;

[0073] 5) Loads with fans or pumps, and whose secondary torque coefficient is within (A) Q ,1) inside.

[0074] Specifically, based on the above scheme, each type of motor is aggregated into one motor, the equivalent circuit of the aggregated motor is a T-type circuit, and the impedance parameters of the aggregated motor are obtained by capacity weighting, as shown in equations (9) and (10).

[0075]

[0076]

[0077] In the formula, the subscript "eq" represents the parameters of the polymer motor; z eq For the impedance of the polymer motor; z i Let R be the impedance of the i-th motor, which can be expressed as the stator resistance R. s Stator leakage impedance X sl Rotor resistance R r Rotor leakage reactance X rl and excitation reactance X m P represents the number of motors to be aggregated; P Ni P is the rated power of the i-th motor; Neq This refers to the rated power of the polymer motor.

[0078] Polymer motor slip s eq From the load torque T Leq The decision is as shown in equations (11) and (12).

[0079]

[0080]

[0081] In the formula, Z Σeq Z meq Z req These are the total impedance, excitation impedance, and rotor-side impedance of the polymer motor, respectively; R req For the rotor resistance of the polymer motor; k eq For the load rate of the polymer motor; A eq This represents the load torque coefficient of the polymer motor.

[0082] The load rate and load torque coefficient of the polymer motor are obtained by weighting the capacity of each motor, as shown in equations (13) and (14).

[0083]

[0084]

[0085] Step S12: Determine the voltage regulation objective function based on the reactive power that the infinite power supply in the transformer area can generate.

[0086] Specifically, the process of determining the voltage regulation target function in this embodiment of the invention includes:

[0087] (1) When the reactive power that the infinite power source in the distribution area can generate is less than the reactive power margin, the minimum reactive power of the load is taken as the target function for voltage regulation. (2) When the reactive power that the infinite power source in the distribution area can generate is greater than or equal to the reactive power margin, the minimum active power of the load is taken as the target function for voltage regulation.

[0088] Specifically, when the reactive power supply in the distribution area is insufficient, the objective function f is to minimize the reactive power of the load; when the reactive power supply in the distribution area is sufficient, the objective function f is to minimize the active power of the load, as shown in equation (15).

[0089]

[0090] In the formula: n is the transformer tap adjustment amount; R IM X IM The total resistance and reactance of the five polymer motors connected in parallel; Q s Q represents the reactive power that can be generated by the reactive power source within the transformer area. set This is the reactive power margin, used to determine whether the reactive power supply in the transformer area is sufficient.

[0091] Step S13: Optimize the voltage regulation objective function using multiple preset constraints to obtain the optimized transformer tap. The preset constraints include the voltage-power characteristic constraints of each type of motor group.

[0092] Specifically, the embodiments of the present invention formulate different voltage regulation target functions according to the actual power conditions of the distribution area, and take into account four types of constraints: load-side voltage constraints, load-side current constraints, transformer tap constraints, and motor group voltage-power characteristic constraints, so as to achieve optimized regulation of the power of the distribution area and achieve the goal of economical operation of the distribution area.

[0093] Specifically, active voltage regulation should consider the actual load conditions and voltage-power regulation characteristics of the motor group within the distribution area. To simplify the calculation process and improve control efficiency, a multi-motor aggregation model is used to approximate the voltage-power regulation characteristics of all motors in the distribution area. When the voltage regulation objective function is to minimize reactive power, the constraint is shown in equation (16); when the voltage regulation objective function is to minimize active power, the constraint is shown in equation (17). The voltage-power characteristic constraints of the motor group for each type of motor are as follows:

[0094]

[0095]

[0096] Among them, P i|0.8<U<1.2 Q i|0.8<U<1.2 This represents the active and reactive power input to the i-th polymer motor when the voltage is between 0.8 and 1.2.

[0097] Specifically, to ensure the normal operation of the motor and improve the service life of the equipment, the load-side voltage is specified to be adjustable within a certain range. The load-side voltage constraint conditions are as follows:

[0098] U min <U<U max (18)

[0099] Among them, Umax U min These are the upper and lower limits of the load-side voltage, respectively, and U is the motor terminal voltage.

[0100] Specifically, to ensure that the motor windings do not overheat, the load-side current should not be too large. The load-side current constraint is as follows:

[0101] I min IM max (19)

[0102] Among them, I IM I represents the total current in the transformer area. min The set minimum current value; I max This is the set maximum current value.

[0103] Specifically, the high-voltage side turns ratio of an on-load tap-changing transformer is adjustable, but it has fixed tap positions. This constraint must be met during tap adjustment. The transformer tap constraint conditions are as follows:

[0104]

[0105] Where S represents the transformer tap, with a value ranging from -8 to +8; n step U represents the voltage adjustment amount per step of the transformer. N U is the rated voltage on the load side, and U is the motor terminal voltage.

[0106] Step S14: Based on transformer tap optimization, adjust the tap position of the on-load tap-changing transformer.

[0107] By way of example, embodiments of the present invention are illustrated with examples. Figure 4 The voltage regulation method shown is explained below, with specific steps as follows:

[0108] Step 1: Obtain the parameters of the induction motors in the distribution area and the load conditions of each motor. The motor parameters are shown in Table 1. There are a total of 9 motors in the distribution area, and some motors have the same parameters. The motor load conditions are shown in Table 2. Table 2 provides the load factor k when the motor is carrying a constant power load; and the load torque factor A and M when the motor is carrying a fan-type load. T1 To M T9 This refers to the first to ninth motors within the transformer area.

[0109] Table 1 Motor Parameter Table

[0110]

[0111]

[0112] Table 2 Load Status of Motors in Transformer Areas

[0113] ​​

[0114] Step 2: Calculate the voltage regulation characteristic curves of the three motors in Table 1 using equations (1) to (5). Taking motor M2 as an example, when the stator voltage per unit value increases from 0.8 to 1.2, the active power change curve of the motor under constant power load is as follows: Figure 5 As shown; the reactive power change curve of the motor under constant power load is as follows. Figure 6 As shown; the reactive power variation curve of the motor when driving a fan-type load is as follows. Figure 7 As shown.

[0115] Step 3: Combining the voltage-power regulation characteristics of each motor in Step 2, analyze the changing trends of active and reactive power with increasing voltage under different load conditions, and obtain the critical load rate K of each motor. P,i K Q,i With critical torque coefficient A Q,i The critical load factor K of the transformer area is calculated using equations (6) to (8). P =0.23, K Q =0.72 and the critical torque coefficient A of the transformer area Q =0.77.

[0116] Table 3 Critical load rate and critical torque coefficient of each motor

[0117]

[0118] Step 4: Combining the critical load rate and critical torque coefficient of the transformer area in Step 3 with the load conditions of the 9 motors in the transformer area in Table 2, classify the motors according to Table 4. Then, calculate the aggregated motor parameters based on equations (9)-(10) and the motor parameters in Table 1, as shown in Table 5, M eq1 To M eq5 This indicates five polymer motors in the distribution area.

[0119] Table 4 Motor Classification Results

[0120]

[0121] Table 5. Parameter Table of Polymer Motor

[0122]

[0123] Step 5: Determine if the reactive power supply in the transformer area is sufficient. This embodiment discusses two cases: 1) If the reactive power supply in the transformer area is insufficient, the objective function is... 2) If the reactive power supply in the transformer area is sufficient, then the objective function is: Determine the parameters of the active voltage regulation settings in equations (16) to (20): U min =0.8pu, U max =1.2pu, Imin =1.1pu、I max =1.2pu, n step =0.0125, U N =1.0pu, The rated capacity of the transformer area is 1.2 MVA.

[0124] Step 6: Solve the planning problem shown in equations (15)-(20) to obtain the optimal tap position. When the reactive power supply of the transformer area is insufficient, S = +5, and the node voltage U = 0.9412 pu; when the reactive power supply of the transformer area is sufficient, S = -6, and the node voltage U = 1.0811 pu.

[0125] Step 7: Transmit the optimized tap position signal to the transformer in the distribution area and adjust the transformer tap position.

[0126] Table 6 compares the total current and total power of the distribution transformer area when the active voltage regulation control strategy is adopted. It can be seen that when the reactive power supply of the distribution transformer area is insufficient, the total reactive power of the distribution transformer area decreases by 0.0475 pu (7.49%) compared to not adopting the active voltage regulation strategy; when the reactive power supply of the distribution transformer area is sufficient, the total active power of the distribution transformer area decreases by 0.0008 pu (0.08%) compared to not adopting the active voltage regulation strategy. This indicates that the active voltage regulation control strategy proposed in this invention can effectively reduce the total reactive power of the distribution transformer area and has important reference value for the active voltage regulation method of distribution transformer areas containing motor groups and for the economical operation of distribution transformer areas.

[0127] Table 6 Comparison of Optimization Results

[0128]

[0129] Example 2

[0130] This invention provides an active voltage regulation system for a distribution transformer substation's induction motor group. The main circuit of the distribution transformer substation includes: an infinite power supply, an on-load tap-changing transformer, and multiple induction motors. The infinite power supply simultaneously powers multiple induction motors through the on-load tap-changing transformer. Figure 8 As shown, the system includes:

[0131] The classification and aggregation module 1 is used to classify the induction motors in the transformer area according to their load characteristics and aggregate each type of motor; this module executes the method described in step S11 of embodiment 1, which will not be repeated here.

[0132] Objective function module 2 is used to determine the voltage regulation objective function based on the reactive power that the infinite power supply in the transformer area can generate; this module executes the method described in step S12 of embodiment 1, which will not be repeated here.

[0133] The optimization solution module 3 is used to optimize the voltage regulation objective function using multiple preset constraints to obtain the optimal transformer tap. The preset constraints include the voltage-power characteristic constraints of the motor group for each type of motor. This module executes the method described in step S13 of embodiment 1, which will not be repeated here.

[0134] Adjustment module 4 is used to adjust the tap position of the on-load tap-changing transformer based on transformer optimization tap position; this module performs the method described in step S14 of embodiment 1, which will not be repeated here.

[0135] Specifically, such as Figure 1 As shown, the active voltage regulation system for induction motor groups in the distribution substation of this invention includes: the main circuit of the distribution substation, a data acquisition and transmission module, an optimized tap calculation module, and a motor group classification and aggregation module.

[0136] Specifically, the main circuit of the distribution substation includes: an on-load tap-changing transformer and a group of induction motors; the data acquisition and transmission module includes: a voltage sensor and a transformer tap changer signal transmission unit; the optimized tap changer calculation module includes: a data receiving unit and a planning problem solving unit; the motor group classification and aggregation module includes: a motor load rate classification unit; a motor torque coefficient classification unit; and a motor group aggregation unit. In the main circuit of the distribution substation, the step-down on-load tap-changing transformer is connected to multiple parallel induction motors and transmits power to the distribution substation. In the data acquisition and transmission module, the voltage sensor is connected to the motor terminals and measures the motor terminal voltage in real time. The optimized tap changer calculation module is connected to the voltage sensor and the motor group classification and aggregation module, and calculates the optimized transformer tap based on the distribution substation's voltage regulation target through the planning problem solving unit. The transformer tap changer signal transmission unit is connected to the transformer and transmits the optimized tap changer signal to the on-load tap-changing transformer for tap adjustment.

[0137] Specifically, the main circuit of the distribution transformer area is used to actively regulate the taps of the distribution transformer area and change the load-side voltage in order to regulate the active and reactive power of the load.

[0138] Specifically, the data acquisition and transmission module is used to: 1) measure the terminal voltage of the motor in the distribution substation and transmit the voltage signal to the transformer tap optimization calculation module; 2) transmit the tap optimization signal to the transformer in the distribution substation and perform optimized control of the transformer tap.

[0139] Specifically, the motor group classification and aggregation module is used to: 1) classify motor groups according to load characteristics such as load type and load rate to ensure that the voltage-power regulation characteristics of various types of motors are consistent; 2) aggregate each type of motor group into one motor, and obtain the transformer optimized tap by combining the voltage-power regulation characteristics of each aggregated motor.

[0140] Example 3

[0141] This invention provides a computer device, such as... Figure 9 As shown, the system includes: at least one processor 401, such as a CPU (Central Processing Unit), at least one communication interface 403, a memory 404, and at least one communication bus 402. The communication bus 402 is used to enable communication between these components. The communication interface 403 may include a display screen or a keyboard; optionally, the communication interface 403 may also include a standard wired interface or a wireless interface. The memory 404 may be high-speed RAM (Random Access Memory) or non-volatile memory, such as at least one disk storage device. Optionally, the memory 404 may also be at least one storage device located remotely from the processor 401. The processor 401 can execute the active voltage regulation method for the distribution substation induction motor group of Embodiment 1. The memory 404 stores a set of program code, and the processor 401 calls the program code stored in the memory 404 to execute the active voltage regulation method for the distribution substation induction motor group of Embodiment 1.

[0142] The communication bus 402 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The communication bus 402 can be divided into an address bus, a data bus, and a control bus, etc. For ease of representation, Figure 9 The symbol is represented by only one line, but this does not mean that there is only one bus or one type of bus.

[0143] The memory 404 may include volatile memory, such as random-access memory (RAM); the memory may also include non-volatile memory, such as flash memory, hard disk drive (HDD) or solid-state drive (SSD); the memory 404 may also include a combination of the above types of memory.

[0144] The processor 401 can be a central processing unit (CPU), a network processor (NP), or a combination of CPU and NP.

[0145] The processor 401 may further include a hardware chip. This hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0146] Optionally, the memory 404 is also used to store program instructions. The processor 401 can call the program instructions to implement the active voltage regulation method for the distribution substation induction motor group as described in Embodiment 1 of this application.

[0147] This invention also provides a computer-readable storage medium storing computer-executable instructions that can execute the active voltage regulation method for the induction motor group in the distribution substation of Embodiment 1. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium may also include combinations of the above types of memory.

[0148] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A power distribution zone induction motor fleet active voltage regulation method, characterized by, The main circuit of the distribution substation includes: an infinite power supply, an on-load tap-changing transformer, and multiple induction motors. The infinite power supply simultaneously powers the multiple induction motors through the on-load tap-changing transformer. The method includes: The induction motors in the transformer area are classified according to their load characteristics, and each type of motor is then grouped together. Based on the reactive power that the infinite power source in the transformer area can generate, determine the voltage regulation objective function; By using multiple preset constraints, the voltage regulation objective function is optimized and solved to obtain the optimal transformer tap. The preset constraints include the voltage-power characteristic constraints of each type of motor group. Based on the optimized tap position of the transformer, the tap position of the on-load tap-changing transformer is modulated; The process of classifying induction motors within a distribution area according to load characteristics includes: calculating the input active power and reactive power of each motor within a preset voltage per-unit value range, or a preset load rate range, or a preset secondary torque coefficient range at different voltages, and obtaining voltage-voltage per-unit value curves, voltage-load rate curves, and voltage-secondary torque coefficient curves; determining the active critical load rate, reactive critical load rate, and critical torque coefficient based on the voltage-voltage per-unit value curves, voltage-load rate curves, and voltage-secondary torque coefficient curves; and classifying the induction motors within the distribution area according to the active critical load rate, reactive critical load rate, and critical torque coefficient.

2. The power distribution zone induction motor fleet active voltage regulation method of claim 1, wherein, The process of determining the voltage regulation objective function based on the reactive power output of the infinite power source in the transformer area includes: When the reactive power that the infinite power supply in the transformer area can generate is less than the reactive power margin, the minimum reactive power of the load is taken as the target function for voltage regulation. When the reactive power that the infinite power source in the distribution area can generate is greater than or equal to the reactive power margin, the minimum active power of the load is taken as the target function for voltage regulation.

3. The active voltage regulation method for a distribution substation induction motor group according to claim 1, characterized in that, When the minimum reactive power of the load is taken as the objective function for voltage regulation, the voltage-power characteristic constraints of the motor group for each type of motor are as follows: When the minimum active power of the load is taken as the objective function for voltage regulation, the voltage-power characteristic constraints of the motor group for each type of motor are as follows: wherein P i|0.8<U<1.2 , Q i|0.8<U<1.2 indicates the i The polyphase machine voltage inputs active power and reactive power in the interval 0.8 to 1.

2.

4. The active voltage regulation method for a distribution substation induction motor group according to claim 1, characterized in that, The preset constraints also include: load-side voltage constraints; The load-side voltage constraint condition is as follows: wherein, U max , U min are respectively a set upper and lower load-side voltage limit, U is a machine terminal voltage.

5. The active voltage regulation method for a distribution substation induction motor group according to claim 1, characterized in that, The preset constraints also include: load-side current constraints; The load-side current constraint condition is as follows: wherein, I IM is the total current of the transformer; I min is the set minimum current; I max is the set maximum current.

6. The active voltage regulation method for a distribution substation induction motor group according to claim 1, characterized in that, The preset constraints also include: transformer tap constraints; The transformer tap constraint conditions are: wherein, S is the transformer gear, taking values in the range -8 to +8; n step is the transformer voltage adjustment per gear; U N is the load side rated voltage, U is the motor terminal voltage.

7. A power distribution district induction motor fleet active voltage regulation system, characterized by, The main circuit of the power distribution area includes: an infinite power supply, an on-load tap-changing transformer, and multiple induction motors. The infinite power supply simultaneously powers multiple induction motors through the on-load tap-changing transformer. The system includes: The classification and aggregation module is used to classify induction motors in the transformer area according to their load characteristics and aggregate each type of motor. The objective function module is used to determine the voltage regulation objective function based on the reactive power that the infinite power supply in the transformer area can generate; The optimization solution module is used to optimize the voltage regulation objective function using multiple preset constraints to obtain the optimal transformer tap. The preset constraints include the voltage-power characteristic constraints of each type of motor group. The adjustment module is used to adjust the tap position of the on-load tap-changing transformer based on the optimized tap position of the transformer. The process of classifying induction motors within a distribution area according to load characteristics includes: calculating the input active power and reactive power of each motor within a preset voltage per-unit value range, or a preset load rate range, or a preset secondary torque coefficient range at different voltages, and obtaining voltage-voltage per-unit value curves, voltage-load rate curves, and voltage-secondary torque coefficient curves; determining the active critical load rate, reactive critical load rate, and critical torque coefficient based on the voltage-voltage per-unit value curves, voltage-load rate curves, and voltage-secondary torque coefficient curves; and classifying the induction motors within the distribution area according to the active critical load rate, reactive critical load rate, and critical torque coefficient.

8. A computer device, comprising: include: At least one processor, and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to cause the at least one processor to perform the active voltage regulation method for a distribution substation induction motor group as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to execute the active voltage regulation method for a distribution substation induction motor group as described in any one of claims 1-6.

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