Three-phase imbalance adjustment and reactive compensation method and system
By using three-phase unbalanced adjustment and reactive power compensation controller and particle swarm optimization algorithm in the capacity regulating transformer table area, the low-voltage side voltage unevenness and reactive power compensation problems caused by three-phase load imbalance are solved, and an efficient solution for voltage equalization and reactive power compensation is achieved.
Patent Information
- Application Number
- CN202411605839.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-12
- Publication Date
- 2025-03-25
AI Technical Summary
When the three-phase load in the capacity regulating transformer table is unbalanced, the voltage on the low-voltage side is uneven, and it is difficult for the prior art to achieve three-phase unbalance adjustment and reactive power compensation at the same time, especially when the load changes in real time.
The operation data of the capacity-regulating transformer is obtained through the three-phase imbalance adjustment and reactive power compensation controller, and the power equation of the power network node is established, and the real-time active and reactive power of the three-phase imbalance and reactive power of the reactive power of the reactive power of the reactive power of the three-phase imbalance and reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the reactive power of the re Using particle swarm optimization algorithm and phase encoding technology, the optimal control strategy is obtained to adjust the three-phase imbalance and compensate for reactive power.
When the three-phase load is unbalanced in the capacity-regulating transformer table area, the voltage on the low-voltage side is balanced, and the load reactive power and the transformer's own reactive power are compensated at the same time, improving the stability and power quality of the power system.
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Figure CN119695949A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of low-voltage power distribution, and in particular to a three-phase unbalanced regulation and reactive power compensation method and system. Background Art
[0002] The capacity-adjusting transformer can automatically adjust its capacity according to the load size, so that it can adjust its capacity to a small capacity when the load is small. When the capacity is small, the no-load loss of the transformer is reduced by about 2 / 3, so it can save energy to a large extent. However, the current capacity-adjusting transformer mainly adopts the winding transformation method to achieve capacity adjustment, that is, the winding connection group is Dyn11 when the capacity is large, and Yyn0 when the capacity is small. When the capacity is large, the zero-sequence impedance is small because the high-voltage winding D connection is short-circuited to the zero-sequence current, but it does have a large zero-sequence impedance when the capacity is small. When the transformer is running at a small capacity and there is an unbalanced three-phase load on the low-voltage side, the zero-sequence impedance will generate a zero-sequence voltage, causing the transformer low-voltage side to have different three-phase voltages, such as a phase voltage of more than 250V, while the other phase is only about 190V, which will seriously affect the voltage quality of the capacity-adjusting transformer area.
[0003] The low-voltage side of the transformer area where capacitors and reactors are installed in different parallel ways will cause different changes in the three-phase active current and reactive current of the area, without causing an increase in the overall active loss of the area. For example, installing capacitors between phases will transfer the active current of the leading phase to the lagging phase, and can simultaneously compensate for the reactive current of the two phases of the capacitors installed between phases. However, the load changes in real time, and different combinations of capacitors and reactors are required in real time to maintain the balance of the three-phase current and perform reactive compensation, which makes it difficult to achieve real-time balance. Usually, the three-phase unbalanced regulation and reactive compensation device will install a fixed number of capacitors or reactors and their switching switches between the three phases or between phase zero, and change the three-phase active and reactive current changes by controlling their switching switches. If an exhaustive algorithm is used, a lot of complex programming and huge calculations are required, and it is difficult to take into account the effects of three-phase unbalance and reactive compensation. If metering is performed on the high-voltage side of the transformer, the reactive power of the transformer itself cannot be compensated. Summary of the invention
[0004] In view of the above existing problems, the present invention is proposed.
[0005] Therefore, the present invention provides a three-phase unbalanced regulation and reactive power compensation method and system to solve the problem of uneven voltage on the low-voltage side when the three-phase load in the capacity-regulating transformer area is unbalanced, and at the same time compensate for the load reactive power and the reactive power of the transformer itself.
[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:
[0007] In the first aspect, the present invention provides a three-phase unbalanced regulation and reactive power compensation method, including: a three-phase unbalanced regulation and reactive power compensation controller obtains first operating data of a capacity-adjusting transformer; according to the first operating data, a power network node power equation is established to calculate the three-phase real-time active power and reactive power of the three-phase unbalanced and reactive power compensation equipment; a first group coding rule is set based on different connection methods of components of the three-phase unbalanced and reactive power compensation equipment; the maximum values of different group codes are converted into base 1 and used as the upper limits of addresses of different dimensions of a first optimization algorithm, and the first optimization algorithm is used to obtain the optimal control strategy for three-phase unbalanced regulation and reactive power compensation in the capacity-adjusting transformer area.
[0008] As a preferred solution of the three-phase unbalanced regulation and reactive power compensation method of the present invention, the three-phase unbalanced regulation and reactive power compensation controller obtains the first operating data of the capacity-adjusting transformer, including:
[0009] Configuring a collection task of the three-phase unbalanced regulation and reactive power compensation controller, wherein the collection task includes a collection cycle, a capacity mode during collection, and specific indicators to be collected;
[0010] Based on the configured acquisition task, first operation data of the capacity-adjusting transformer is acquired through the communication mode of the capacity-adjusting transformer controller, and the first operation data is preset;
[0011] The real-time three-phase load apparent power of the transformer and the real-time reactive power of the transformer are calculated according to the first operating data preset on the low-voltage side of the transformer.
[0012] As a preferred solution of the three-phase unbalanced regulation and reactive power compensation method described in the present invention, the optimal control strategy for obtaining the three-phase unbalanced regulation and reactive power compensation in the capacity-adjusting transformer area includes:
[0013] According to different connection modes of components in the three-phase unbalanced and reactive power compensation device, a first group coding rule is set, and the maximum values of different group codes are converted into base 1 and used as the upper limits of different dimension addresses of the first optimization algorithm;
[0014] In each iterative calculation process, the first optimization algorithm converts the address after the base conversion into a group code value in the three-phase unbalanced and reactive power compensation device again, and then calculates the three-phase apparent power of the three-phase unbalanced and reactive power compensation device in this iteration;
[0015] The three-phase apparent power on the low-voltage side of the substation is calculated using the current signal collected by the current transformer and the voltage signal collected from the bus. The load apparent power is obtained by subtracting the three-phase apparent power on the low-voltage side of the substation from the actual apparent power of the three-phase unbalanced and reactive compensation equipment.
[0016] As a preferred solution of the three-phase unbalanced regulation and reactive power compensation method described in the present invention, the optimal control strategy for obtaining the three-phase unbalanced regulation and reactive power compensation in the capacity-adjusting transformer area further includes:
[0017] The load apparent power plus the three-phase apparent power obtained in the iterative process can obtain the total three-phase apparent power of the low-voltage side in the iterative calculation process, and the corresponding three-phase current, positive sequence current, negative sequence current and zero sequence current are calculated based on the total three-phase apparent power of the low-voltage side, and the unbalance ε2 caused by the negative sequence current and the unbalance ε0 caused by the zero sequence current are calculated;
[0018] The total reactive power Q of the iteration process including the capacity adjustment transformer is calculated by calculating the total three-phase apparent power on the low-voltage side. za , Q zb , Q zc .
[0019] As a preferred solution of the three-phase unbalanced regulation and reactive power compensation method described in the present invention, the optimal control strategy for obtaining the three-phase unbalanced regulation and reactive power compensation in the capacity-adjusting transformer area further includes:
[0020] When the total reactive power Q za , Q zb , Q zc All are greater than or equal to 0, indicating that the system is not over-compensated. The fitness F is calculated by the following formula:
[0021] F=1-k1*ε2-k2*ε0-k3*(Q za +Q zb +Q zc ) / (Q La +Q Lb +Q Lc +Q tad +Q tbd +Q tcd )
[0022] Among them, k1 represents the weight coefficient of unbalance caused by negative sequence current, k2 represents the weight coefficient of unbalance caused by zero sequence current, k3 represents the weight coefficient of reactive power compensation, Q La , Q Lb , Q Lc Indicates the actual reactive power of three-phase unbalanced and reactive power compensation equipment, Q tad , Q tbd , Q tcd Indicates the real-time three-phase reactive power of the transformer;
[0023] When the total reactive power Q za , Q zb , Qzc When F is less than 0, it means that reactive power is over-compensated, so let F = 0;
[0024] During the iteration process of the first optimization algorithm, the best fitness with the largest fitness F value in all iterative cycles and its corresponding particle address are recorded. After the iteration, the corresponding binary address is converted into a group coding value within the three-phase unbalanced and reactive power compensation equipment, that is, a capacitor or reactor switching control instruction with a clear meaning is obtained.
[0025] As a preferred solution of the three-phase unbalanced regulation and reactive power compensation method of the present invention, the three-phase unbalanced and reactive power compensation equipment includes a three-phase unbalanced regulation and reactive power compensation controller, busbars a, b, c, n, capacitors connected in parallel between the three phases and between the three phases and the ground, reactors and switching switches, three-phase current transformers, and wiring of the above equipment;
[0026] When the three-phase unbalanced and reactive power compensation equipment is working, the a, b, c, and n main busbars are connected to the low-voltage outgoing line of the substation area. The three-phase current transformer is installed at the front end of the connection point between the substation area load and the equipment and the low-voltage outgoing line of the substation area. The voltage signal required by the equipment is directly collected by the controller from the a, b, c, and n busbars.
[0027] As a preferred solution of the three-phase unbalanced regulation and reactive power compensation method of the present invention, the establishment of the power network node power equation to calculate the three-phase real-time active power and reactive power of the three-phase unbalanced and reactive power compensation equipment includes:
[0028] The three-phase busbars of the three-phase unbalanced and reactive power compensation device are regarded as three points in the power network, and the n line is regarded as the grounding point in the power network;
[0029] According to the capacitors and reactors in the three-phase unbalanced and reactive power compensation equipment, the capacity of the capacitors and reactors, the number of reactors and the connection with the a, b, c and n buses, a three-node power network admittance matrix Y is constructed;
[0030] Acquire a voltage matrix according to the three-phase voltage signals collected by the three-phase unbalanced and reactive power compensation equipment;
[0031] Based on the three-node power network admittance matrix Y and the voltage matrix, the apparent power matrix composed of the input active and reactive power of the three nodes is calculated, and then the three-phase real-time active power and reactive power of the three-phase unbalanced and reactive compensation equipment are obtained.
[0032] In a second aspect, the present invention provides a three-phase unbalanced regulation and reactive power compensation system, comprising:
[0033] A data acquisition module, used for the three-phase unbalanced regulation and reactive power compensation controller to acquire first operating data of the capacity regulating transformer;
[0034] A power calculation module, used to establish a power network node power equation according to the first operation data to calculate the three-phase real-time active power and reactive power of the three-phase unbalanced and reactive compensation equipment;
[0035] A group coding rule setting module, used for setting a first group coding rule based on different connection modes of components of three-phase unbalanced and reactive compensation equipment;
[0036] The optimal strategy acquisition module is used to convert the maximum values of different group codes into binary system as the upper limits of different dimensional addresses of the first optimization algorithm, and use the first optimization algorithm to obtain the optimal control strategy for three-phase unbalanced regulation and reactive power compensation in the capacity-adjusting transformer area.
[0037] In a third aspect, the present invention provides a computing device, comprising:
[0038] Memory and processor;
[0039] The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the three-phase unbalanced regulation and reactive power compensation method are implemented.
[0040] In a fourth aspect, the present invention provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the three-phase unbalanced regulation and reactive power compensation method.
[0041] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention provides a three-phase unbalanced regulation and reactive power compensation method and system, which calculates the capacity of the capacity-adjusting transformer itself to determine its real-time reactive power as part of the reactive power compensation target, thereby solving the problem of low power factor during high-voltage side metering; at the same time, the algorithm for establishing the power equation of the power network node is used to simplify the power calculation process of the three-phase unbalanced and reactive power compensation equipment, thereby improving the efficiency of program writing; in addition, the present invention introduces an arbitrary base encoding technology based on the connection mode of the internal components of the three-phase unbalanced and reactive power compensation equipment, and realizes the function of directly converting the encoding into the switching command. Finally, the particle swarm optimization algorithm is used to shorten the calculation time, and the consideration of the imbalance and reactive power compensation effect of the three-phase zero-sequence current and negative-sequence current is added to the fitness function, effectively balancing the needs of three-phase unbalanced regulation and reactive power compensation. BRIEF DESCRIPTION OF THE DRAWINGS
[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.
[0043] Figure 1 A schematic diagram of the overall process logic of a three-phase unbalanced regulation and reactive power compensation method according to an embodiment of the present invention;
[0044] Figure 2 A schematic diagram of an equivalent circuit for calculating reactive power of a transformer in a three-phase unbalanced regulation and reactive power compensation method according to an embodiment of the present invention;
[0045] Figure 3 A schematic diagram of the wiring principle of a three-phase unbalanced and reactive power compensation device of a three-phase unbalanced regulation and reactive power compensation method according to an embodiment of the present invention;
[0046] Figure 4 A schematic diagram of a three-node power network of a three-phase unbalanced regulation and reactive power compensation method according to an embodiment of the present invention;
[0047] Figure 5 A schematic diagram of device group coding of a three-phase unbalanced regulation and reactive power compensation method according to an embodiment of the present invention;
[0048] Figure 6 A particle swarm algorithm flow chart of a three-phase unbalanced regulation and reactive power compensation method according to an embodiment of the present invention;
[0049] Figure 7 The present invention is a flowchart of a fitness calculation subroutine of a three-phase unbalanced regulation and reactive power compensation method according to an embodiment of the present invention. DETAILED DESCRIPTION
[0050] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.
[0051] Example 1
[0052] Reference Figure 1-Figure 7 As an embodiment of the present invention, a three-phase unbalanced regulation and reactive power compensation method is provided, such as Figure 1 The specific steps shown include:
[0053] S100: The three-phase unbalanced regulation and reactive power compensation controller obtains first operating data of the capacity regulating transformer;
[0054] S200: Establishing a power network node power equation according to the first operation data to calculate the three-phase real-time active power and reactive power of the three-phase unbalanced and reactive compensation device;
[0055] S300: Setting a first grouping coding rule based on different connection modes of components of three-phase unbalanced and reactive power compensation equipment;
[0056] S400: converting the maximum values of different group codes into binary system and using them as upper limits of different dimension addresses of the first optimization algorithm, and using the first optimization algorithm to obtain the optimal control strategy of three-phase unbalanced regulation and reactive power compensation in the capacity-adjusting transformer area;
[0057] It should be noted that the present invention provides a three-phase unbalanced regulation and reactive power compensation method and system, which calculates the capacity of the capacity-adjusting transformer itself to determine its real-time reactive power as part of the reactive power compensation target, thereby solving the problem of low power factor during high-voltage side metering; at the same time, the algorithm for establishing the power equation of the power network node is used to simplify the power calculation process of the three-phase unbalanced and reactive power compensation equipment, thereby improving the efficiency of program writing; in addition, the present invention introduces an arbitrary base encoding technology based on the connection mode of the internal components of the three-phase unbalanced and reactive power compensation equipment, and realizes the function of directly converting the encoding into the switching command. Finally, the particle swarm optimization algorithm is used to shorten the calculation time, and the consideration of the unbalanced and reactive power compensation effects of the three-phase zero-sequence current and negative-sequence current is added to the fitness function, effectively balancing the needs of three-phase unbalanced regulation and reactive power compensation.
[0058] In the embodiment of the present application, the above step S100 includes the following sub-steps A1-A2;
[0059] In A1: the three-phase unbalanced regulation and reactive power compensation controller obtains first operating data of the capacity regulating transformer;
[0060] In A2: calculating the real-time load power of the transformer and the real-time reactive power of the transformer itself according to the acquired first operation data;
[0061] In an optional embodiment, the first operating data may be the effective value or instantaneous value of each phase voltage and the effective value or instantaneous value of each phase current of the capacity regulating transformer; may be the active power, reactive power, and overall power factor of each phase; may also be harmonic content and temperature data;
[0062] Specifically, in the present application, the first operating data is the large capacity value, small capacity value, large capacity state and corresponding no-load current, small capacity state and corresponding no-load current, and short-circuit impedance of the capacity-regulating transformer;
[0063] In an optional embodiment, the calculation of the real-time reactive power of the transformer itself includes:
[0064] The capacity-adjusting transformer can be equivalent to any phase in either large or small capacity state. Figure 2 The circuit shown, Figure 2 Where L0 and R0 represent the excitation inductance and resistance of the transformer core during excitation. Only the excitation current, i.e., the no-load current I0, can generate reactive power on L0 and active power on R0. Since the no-load loss of the transformer is generally small, almost all of the no-load current is used to generate no-load reactive power. Assuming the rated phase voltage of the transformer is Un, the single-phase no-load reactive power generated by the transformer is:
[0065] Q0=Un*I0
[0066] The rated single-phase apparent power of the transformer is:
[0067] S=Un*In
[0068] According to the above formula and transformer parameters, the no-load current I0% is the actual no-load current I0 and the rated current I n Percentage is I0 / I n *100 gets:
[0069] Q0=S*I0 / I n =S*I0% / 100
[0070] Figure 2 Medium k1 , R k1 , L k2 , R k2 Respectively represent the transformer high-voltage side and low-voltage side winding inductance and resistance, because I0 is relatively small relative to the load current I L Can be ignored, I L In L k1 and L k2 Reactive power is generated on R k1 , R k2 Active power is generated on the k1 , R k1 , L k2 , R k2 The short-circuit impedance of the transformer is mainly composed of the inductive component, so L is often used. k1 , L k2 The resulting inductive reactance represents the actual value of the transformer short-circuit impedance X k . And when I L is the transformer rated current I L The power generated by the single-phase short-circuit impedance is:
[0071] Q k=In 2 *X k
[0072] Assume the rated impedance of the transformer is Z n , the transformer single-phase rated apparent power can also be written as:
[0073] S=In 2 *Z N
[0074] The power generated by the single-phase short-circuit impedance, the transformer single-phase rated apparent power and the transformer parameter short-circuit impedance U k % is the actual value of short-circuit impedance X k Same as Z n Percentage is X K / Z n *100 gets:
[0075] Q K =S*X K / Z n =S*U k % / 100
[0076] When the load is any single-phase apparent power S L When the load current I L for:
[0077] I L =S L / Un
[0078] At this time, the reactive power generated by the single-phase short-circuit impedance is:
[0079] Q KL =I L 2 *X k
[0080] Then we get:
[0081] Q KL =S L 2 / S*U k / 100
[0082] Because the no-load reactive power Q KL It is generated by the transformer to maintain the terminal voltage. Therefore, even with load, no-load reactive power still exists. Therefore, the transformer's own single-phase reactive power Q at any time t =Q0+Q KL ;
[0083] From the above analysis, the unbalanced regulation and reactive power compensation controller and the capacity-adjusting transformer controller obtain the real-time large and small capacity status of the transformer through communication, and set the large and small rated capacity values of the transformer capacity-adjusting transformer in advance, that is, the rated apparent power is: S d and S x , single-phase value is Sd / 3 and S x / 3, corresponding to no-load current I 0d % and I 0X %, short circuit impedance U kd % and U kx %, the real-time three-phase load apparent power of the transformer is S a , S b , S c It can be calculated by the controller itself based on the three-phase voltage and current sampling. Taking the transformer large capacity state a phase as an example, the transformer real-time reactive power Q can be calculated according to the following formula tad :
[0084] Q tad =S d *I 0d % / 3 / 100+3*S a 2 / S d *U kd % / 100
[0085] The a-phase parameter S in the above formula a Replace with b phase parameter S b or S c , the reactive power Q of phase b or c of the transformer under large capacity condition can be calculated tbd or Q tcd , the parameter S in the above formula d ,I 0d , U kd Replace with small capacity parameter S x ,I 0x , U kx , the reactive power Q of phase a of the transformer under the condition of small capacity can be calculated tax Similarly, the reactive power Q of phase b or c under small capacity can be calculated. tbx or Q tcx .
[0086] It should be noted that the above step S100 can timely and accurately grasp the current state of the power system through real-time monitoring and precise calculation, thereby effectively identifying and quantifying the problems of three-phase imbalance and insufficient reactive power. This not only helps to quickly respond to system changes and ensure the stable operation of the power system, but also provides reliable input for subsequent optimization algorithms, so that the entire control system can maintain efficient and accurate regulation capabilities in a dynamically changing environment, and ultimately achieve optimal configuration and utilization of power resources.
[0087] In the embodiment of the present application, the above step S200 establishes the power network node power equation according to the first operation data to calculate the three-phase real-time active power and reactive power of the three-phase unbalanced and reactive compensation device, specifically including:
[0088] In an optional embodiment, if Figure 3 The following is a wiring schematic diagram of a three-phase unbalanced and reactive power compensation device. The dashed line includes the device in the example. The power components in this example are all capacitors. The device includes a controller that implements the calculation and control method of this patent, busbars a, b, c, n, capacitors connected in parallel between three phases and between three phases and ground n, reactors and switching switches KAB1~KC4, three-phase current transformers CTA, CTB, CTC, and the wiring of the above devices; in this example, 8 capacitors are connected in parallel between ab, ac, and bc phases, respectively. Figure 3 In CAB1~CBC8, capacitors an, bn, cn relative to ground n are connected in parallel with 4 capacitors, respectively Figure 3 When the equipment is working, the a, b, c, n busbars are as follows Figure 3 The low voltage outgoing line of the same substation is connected, and the current transformers of phases a, b, and c are CTA, CTB, and CTC. Figure 3 Installed before the load in the substation and the point where the equipment is connected to the low-voltage outlet line in the substation. The voltage signal required by the equipment is directly collected from the a, b, c, n busbars, and the current signal collected by the current transformer is supplied to the controller, and the controller controls KAB1~KC4 at the same time. To simplify the wiring, the above secondary connection is not marked.
[0089] Specifically, in order to calculate the three-phase imbalance and reactive power compensation effect of the substation, the active power and reactive power of the three-phase imbalance regulation and reactive power compensation equipment must be quickly calculated. The general method requires writing different forms of calculation programs for different connection methods and different capacitance values, and the calculation program is complicated. The calculation method adopted by this patent is a method for establishing a power network node power equation to achieve the purpose of unifying the calculation program form, specifically:
[0090] The a, b, and c three-phase busbars of the three-phase unbalanced and reactive power compensation equipment are regarded as three points 1, 2, and 3 in the power network, and the n line is regarded as the grounding point in the power network. Figure 4 Assuming that the number of capacitors between ab is kab, between ac is kac, between bc is kbc, between an is ka, between bn is kb, between cn is kc, and assuming that the admittance of each capacitor between phases is Yxx, and the admittance of each capacitor between phase zero is Yxn, then the admittance between each node is as follows: Figure 4 As shown;
[0091] according to Figure 4And the knowledge related to the power system, construct the above 3-node power network admittance matrix Y:
[0092]
[0093] Among them, Y 11 , Y 22 , Y 33 is the self-admittance of points 1, 2, and 3, and the others are the mutual admittances between the above points;
[0094] According to the above example assumptions:
[0095]
[0096] The voltage matrix is obtained according to the three-phase voltage signal collected by the three-phase unbalanced and reactive power compensation equipment; the apparent power matrix composed of the input active and reactive power of the three nodes is calculated based on the three-node power network admittance matrix Y and the voltage matrix, and then the three-phase real-time active power and reactive power of the three-phase unbalanced and reactive power compensation equipment are obtained, wherein the calculation of the apparent power matrix composed of the input active and reactive power is:
[0097] S=U·(Y×U T ) *
[0098] Among them, · represents the dot product of the matrix, × represents the cross product of the matrix, and * represents taking the conjugate.
[0099] It should be noted that the above step S200 can accurately reflect the current operating status of the power system and provide a scientific basis for the subsequent control strategy. Through real-time calculation and analysis, the problems of three-phase imbalance and insufficient reactive power can be discovered and quantified in time, thereby providing accurate data support for the formulation of optimized control strategies, ensuring the stability and efficient operation of the power system, and ultimately improving the power quality and system performance.
[0100] In an optional embodiment, the first group coding rule in the above step S300 is set based on different connection methods of three-phase unbalanced and reactive power compensation equipment components, and is mainly used to simplify complex equipment connection relationships into a set of ordered codes; the first group coding rule can be equipment type coding, that is, coding according to the type of equipment, and each type of equipment is assigned a unique identifier; the first group coding rule can be component data and connection method coding, that is, coding according to the number of components and connection methods of the equipment in the power network, ensuring that each position has a clear identification; the first group coding rule can also be capacity level and working status coding, that is, coding according to the capacity level and working status of the equipment, reflecting the real-time operation of the equipment, so as to facilitate consideration of the impact of different capacities in the optimization process;
[0101] In the embodiment of the present application, the first grouping encoding rule uses component data and connection mode encoding;
[0102] For example, continuing the example assumptions detailed in the above equipment composition part and power calculation part, it is assumed that the capacitors connected in parallel between the ab, ac, and bc phases are all capacitors with the same capacity, and the total number is the same, that is, 8. The capacitors connected in parallel between the an, bn, and cn phases are all capacitors with the same capacity, and the total number is the same, that is, 4. In this way, the following can be performed: Figure 5 2 groups of 3-bit codes are shown.
[0103] The first digit of the first group of codes is the number of parallel capacitors between phases ab, the second digit is the number of parallel capacitors between phases ac, and the third digit is the number of parallel capacitors between phases bc. The first digit of the second group of codes is the number of parallel capacitors between phases an and ground, the second digit is the number of parallel capacitors between phases bn and ground, and the third digit is the number of parallel capacitors between phases cn and ground.
[0104] The first group of codes has a value range of 0 to 8 for each bit, and the second group has a value range of 0 to 4 for each bit. Therefore, the 3-bit 9-bit code and the 3-bit 5-bit code can be used to encode the number of capacitors in parallel. For example, the first group of codes 456 means 4 capacitors are connected between ab, 5 between ac, and 6 between bc; the second group of codes 123 means 1 capacitor is connected between an, 2 between bn, and 3 between cn.
[0105] The 3-digit 9-digit maximum value 888 and the 5-digit maximum value 444 are calculated to correspond to the decimal values, which are 728 and 124 respectively, as the upper limit of the 2-dimensional address of the particles in the particle swarm optimization algorithm. The conversion between the values of each base into the conventional algorithm will not be repeated.
[0106] It should be noted that the above step S300 can clearly represent the type, location, connection mode and working status of various devices through coding rules, so that the optimization algorithm can efficiently identify and process different device combinations, thereby quickly finding the optimal control strategy in multi-dimensional space. This coding method not only simplifies the complexity of data processing, but also provides structured and standardized input for the optimization algorithm, ensuring the accuracy and effectiveness of three-phase unbalanced regulation and reactive power compensation, and ultimately improving the operating efficiency and stability of the power system.
[0107] In an optional embodiment, the first optimization algorithm may be a genetic algorithm, which gradually optimizes the quality of the solution by simulating the selection, crossover and mutation operations in the biological evolution process; the first optimization algorithm may be a particle swarm optimization algorithm, which simulates the group behavior of a flock of birds or a school of fish so that each particle moves in the search space and updates its speed and position according to the optimal position of the individual and the group; the first optimization algorithm may be a gradient descent method, which gradually approaches the optimal solution by iteratively updating parameters; the first optimization algorithm may also be a differential evolution algorithm, which generates new candidate solutions through differential mutation and crossover operations, and then updates the population through selection operations.
[0108] In the embodiment of the present application, the first optimization algorithm adopts a particle swarm optimization algorithm, which is an existing intelligent algorithm. The following only describes in detail the parts related to the three-phase unbalanced regulation and reactive power compensation method. The brief process is as follows: Figure 6 shown.
[0109] Specifically, the initialization process specifies that the first dimension of the particle position limit is 0-728, the second dimension of the particle position limit is 0-124, generates a random decimal two-dimensional address of the particle, and sets the number of iterations;
[0110] Specifically, according to the particle swarm optimization algorithm, the particle fitness is calculated in each iterative calculation process. The process is as follows: Figure 7 As shown, by converting the particle decimal address to bit 9 and 5-bit, the number of capacitors in different parallel connection modes can be known, so that the apparent power S of the three-phase unbalanced and reactive compensation equipment can be calculated according to the above three-point power network power equation;
[0111] Specifically, through Figure 3 The current signals collected by the current transformers CTA, CTB, and CTC and the voltage signals collected from the busbars a, b, and c are used to calculate the three-phase apparent power S on the low-voltage side of the platform area. Z When the program is running, the device may have been equipped with capacitors of different types. According to the actual capacitors or reactors that have been equipped, the above power network power equation is used to calculate the actual three-phase apparent power S S .according to Figure 3 Wiring shows the load apparent power S L =S Z -S S , assuming that the reactive power is Q La , Q Lb , Q Lc ;
[0112] The apparent power of the load plus the apparent power S of the three-phase unbalanced and reactive compensation equipment calculated corresponding to the particle position in the above particle swarm iterative calculation process can be obtained as the total three-phase apparent power S of the low-voltage side in the iterative calculation process. ZJ =SL +S, given the apparent power and assuming that the voltage remains unchanged, the corresponding three-phase currents can be calculated, and the positive sequence, negative sequence current and zero sequence current I1, I2, I0 can be calculated. The unbalance degree ε2=I2 / I1 caused by the negative sequence current and the unbalance degree ε0=I0 / I1 caused by the zero sequence current can be calculated;
[0113] Specifically, the total three-phase apparent power S on the low-voltage side during the iterative calculation process is ZJ The three-phase transformer reactive power loss formula is used to calculate the reactive power part Q of the total apparent power on the low-voltage side during the iteration process. ta , Q tb , Q tc , plus the total three-phase apparent power S of the low-voltage side in the iterative calculation process ZJ The reactive power part of the iterative process including the capacity adjustment transformer can be calculated. za , Q zb , Q zc ;
[0114] Specifically, when the total reactive power Q za , Q zb , Q zc All are greater than or equal to 0, indicating that the system is not over-compensated. The fitness F is calculated by the following formula:
[0115] F=1-k1*ε2-k2*ε0-k3*(Q za +Q zb +Q zc ) / (Q La +Q Lb +Q Lc +Q tad +Q tbd +Q tcd )
[0116] Among them, k1 represents the weight coefficient of unbalance caused by negative sequence current, k2 represents the weight coefficient of unbalance caused by zero sequence current, k3 represents the weight coefficient of reactive power compensation, Q La , Q Lb , Q Lc Indicates the actual reactive power of three-phase unbalanced and reactive power compensation equipment, Q tad , Q tbd , Q tcd It represents the real-time three-phase reactive power of the transformer. It can be seen that when the three-phase current on the low-voltage side of the transformer is balanced, that is, ε2 and ε0 are 0, and the reactive power of the transformer is fully compensated, F = 1. When measuring on the low-voltage side, the reactive power of the transformer itself is not included. Therefore, Q ta , Q tb , Q tc If it is 0, it will be ignored.
[0117] Specifically, when the total reactive power Q za , Q zb , Q zc When F is less than 0, it means that reactive power is over-compensated, so let F = 0;
[0118] Specifically, during the first optimization algorithm iteration process, the best fitness with the largest fitness F value in all iterative cycles and its corresponding particle address are recorded. After the iteration is completed, the corresponding binary address is converted into a group coding value within the three-phase unbalanced and reactive compensation equipment. After comparison with the current capacitor parallel form, the number of phase-to-phase or phase-zero capacitors that need to be switched is clearly obtained. After conventional delay judgment, the switching instruction can be issued. The user can determine which capacitor to switch based on the first-in-first-out principle or other principles. This is not the content of this patent.
[0119] It should be noted that the above step S400 not only simplifies the representation of the problem by converting the encoding of the device connection relationship into the input of the optimization algorithm, but also enables the algorithm to efficiently search for the optimal solution in a multi-dimensional space. This method ensures that the optimization process can fully consider all possible device combinations and connection methods, so as to find the most appropriate control strategy, effectively solve the three-phase imbalance and reactive power compensation problems, improve the operating efficiency and stability of the power system, and ultimately achieve a comprehensive improvement in power quality and system performance.
[0120] Example 2
[0121] This embodiment provides a three-phase unbalanced regulation and reactive power compensation system, including a data acquisition module, a power calculation module, a group coding rule setting module and an optimal strategy acquisition module;
[0122] Specifically, the data acquisition module is used for the three-phase unbalanced regulation and reactive power compensation controller to acquire first operating data of the capacity regulating transformer;
[0123] Specifically, the power calculation module is used to establish a power network node power equation according to the first operation data to calculate the three-phase real-time active power and reactive power of the three-phase unbalanced and reactive compensation equipment;
[0124] Specifically, the group coding rule setting module is used to set the first group coding rule based on different connection modes of three-phase unbalanced and reactive power compensation equipment components;
[0125] Specifically, the optimal strategy acquisition module is used to convert the maximum values of different group codes into binary system as the upper limits of addresses of different dimensions of the first optimization algorithm, and use the first optimization algorithm to obtain the optimal control strategy for three-phase unbalanced regulation and reactive power compensation in the capacity-adjusting transformer area.
[0126] It should be noted that the technical solution of the three-phase unbalanced regulation and reactive power compensation system and the technical solution of the above-mentioned three-phase unbalanced regulation and reactive power compensation method belong to the same concept. For the details not described in detail in the technical solution of the three-phase unbalanced regulation and reactive power compensation system in this embodiment, please refer to the description of the technical solution of the above-mentioned three-phase unbalanced regulation and reactive power compensation method.
[0127] The above-mentioned unit modules may be embedded in or independent of a processor in a computer device in the form of hardware, or may be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to the above-mentioned modules.
[0128] This embodiment also provides a computing device, which includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, an operator network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a three-phase unbalanced regulation and reactive power compensation method is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a button, a trackball or a touch pad set on the housing of the computer device, or an external keyboard, touch pad or mouse, etc.
[0129] This embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, the method proposed in the above embodiment is implemented.
[0130] The storage medium proposed in this embodiment and the method proposed in the above embodiment belong to the same inventive concept. The technical details not fully described in this embodiment can be referred to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.
[0131] Through the above description of the implementation methods, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software and necessary general hardware, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ReadOnly, Memory, ROM), random access memory (RandomAccess Memory, RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform the methods of various embodiments of the present invention.
[0132] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.
[0133] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiments of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.
[0134] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.
[0135] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.
[0136] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.
[0137] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.
[0138] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.
Claims
1. A three-phase unbalanced regulation and reactive power compensation method, characterized in that: include: The three-phase unbalanced regulation and reactive power compensation controller obtains first operation data of the capacity regulating transformer; Establishing a power network node power equation according to the first operation data to calculate the three-phase real-time active power and reactive power of the three-phase unbalanced and reactive compensation equipment; Setting a first grouping coding rule based on different connection modes of components of three-phase unbalanced and reactive power compensation equipment; The maximum values of different group codes are converted into base 1 and used as the upper limits of addresses of different dimensions of the first optimization algorithm, and the first optimization algorithm is used to obtain the optimal control strategy for three-phase unbalanced regulation and reactive power compensation in the capacity-adjusting transformer area.
2. The three-phase unbalanced regulation and reactive power compensation method according to claim 1, characterized in that: The three-phase unbalanced regulation and reactive power compensation controller obtains the first operation data of the capacity-adjusting transformer, including: Configuring a collection task of the three-phase unbalanced regulation and reactive power compensation controller, wherein the collection task includes a collection cycle, a capacity mode during collection, and specific indicators to be collected; Based on the configured acquisition task, first operation data of the capacity-adjusting transformer is acquired through the communication mode of the capacity-adjusting transformer controller, and the first operation data is preset; The real-time three-phase load apparent power of the transformer and the real-time reactive power of the transformer are calculated according to the first operating data preset on the low-voltage side of the transformer.
3. The three-phase unbalanced regulation and reactive power compensation method according to claim 1, characterized in that: The optimal control strategy for obtaining three-phase unbalanced regulation and reactive power compensation in the capacity-adjusting transformer area includes: According to different connection modes of components in the three-phase unbalanced and reactive power compensation device, a first group coding rule is set, and the maximum values of different group codes are converted into base 1 and used as the upper limits of different dimension addresses of the first optimization algorithm; In each iterative calculation process, the first optimization algorithm converts the address after the base conversion into a group code value in the three-phase unbalanced and reactive power compensation device again, and then calculates the three-phase apparent power of the three-phase unbalanced and reactive power compensation device in this iteration; The three-phase apparent power on the low-voltage side of the substation is calculated using the current signal collected by the current transformer and the voltage signal collected from the bus. The load apparent power is obtained by subtracting the three-phase apparent power on the low-voltage side of the substation from the actual apparent power of the three-phase unbalanced and reactive compensation equipment.
4. The three-phase unbalanced regulation and reactive power compensation method according to claim 3, characterized in that: The optimal control strategy for obtaining three-phase unbalanced regulation and reactive power compensation in the capacity-adjusting transformer area also includes: The load apparent power plus the three-phase apparent power obtained in the iterative process can obtain the total three-phase apparent power of the low-voltage side in the iterative calculation process, and the corresponding three-phase current, positive sequence current, negative sequence current and zero sequence current are calculated based on the total three-phase apparent power of the low-voltage side, and the unbalance ε2 caused by the negative sequence current and the unbalance ε0 caused by the zero sequence current are calculated; The total reactive power Q of the iterative process including the capacity adjustment transformer is calculated by calculating the total three-phase apparent power on the low-voltage side. za , Q zb , Q zc .
5. The three-phase unbalanced regulation and reactive power compensation method according to claim 4, characterized in that: The optimal control strategy for obtaining three-phase unbalanced regulation and reactive power compensation in the capacity-adjusting transformer area also includes: When the total reactive power Q za , Q zb , Q zc All are greater than or equal to 0, indicating that the system is not over-compensated. The fitness F is calculated by the following formula: F=1-k1*ε2-k2*ε0-k3*(Q za +Q zb +Q zc ) / (Q La +Q Lb +Q Lc +Q tad +Q tbd +Q tcd ) Among them, k1 represents the weight coefficient of unbalance caused by negative sequence current, k2 represents the weight coefficient of unbalance caused by zero sequence current, k3 represents the weight coefficient of reactive power compensation, Q La , Q Lb , Q Lc Indicates the actual reactive power of three-phase unbalanced and reactive power compensation equipment, Q tad , Q tbd , Q tcd Indicates the real-time three-phase reactive power of the transformer; When the total reactive power Q za , Q zb , Q zc When F is less than 0, it means that reactive power is over-compensated, so let F = 0; During the iteration process of the first optimization algorithm, the best fitness with the largest fitness F value in all iterative cycles and its corresponding particle address are recorded. After the iteration, the corresponding binary address is converted into a group coding value within the three-phase unbalanced and reactive power compensation equipment, that is, a capacitor or reactor switching control instruction with a clear meaning is obtained.
6. The three-phase unbalanced regulation and reactive power compensation method according to claim 2, characterized in that: The three-phase unbalanced and reactive power compensation equipment includes a three-phase unbalanced regulation and reactive power compensation controller, busbars a, b, c, n, capacitors connected in parallel between the three phases and between the three phases and the ground, reactors and switching switches, a three-phase current transformer, and wiring of the above equipment; When the three-phase unbalanced and reactive power compensation equipment is working, the a, b, c, and n main busbars are connected to the low-voltage outgoing line of the substation area. The three-phase current transformer is installed at the front end of the connection point between the substation area load and the equipment and the low-voltage outgoing line of the substation area. The voltage signal required by the equipment is directly collected by the controller from the a, b, c, and n busbars.
7. The three-phase unbalanced regulation and reactive power compensation method according to claim 6, characterized in that: The method of establishing the power network node power equation to calculate the three-phase real-time active power and reactive power of the three-phase unbalanced and reactive compensation equipment includes: The three-phase busbars of the three-phase unbalanced and reactive power compensation device are regarded as three points in the power network, and the n line is regarded as the grounding point in the power network; According to the capacitors and reactors in the three-phase unbalanced and reactive power compensation equipment, the capacity of the capacitors and reactors, the number of reactors and the connection with the a, b, c and n buses, a three-node power network admittance matrix Y is constructed; Acquire a voltage matrix according to the three-phase voltage signals collected by the three-phase unbalanced and reactive power compensation equipment; Based on the three-node power network admittance matrix Y and the voltage matrix, the apparent power matrix composed of the input active and reactive power of the three nodes is calculated, and then the three-phase real-time active power and reactive power of the three-phase unbalanced and reactive compensation equipment are obtained.
8. A system using the three-phase unbalanced regulation and reactive power compensation method according to any one of claims 1 to 7, characterized in that: include: A data acquisition module, used for the three-phase unbalanced regulation and reactive power compensation controller to acquire first operating data of the capacity regulating transformer; A power calculation module, used to establish a power network node power equation according to the first operation data to calculate the three-phase real-time active power and reactive power of the three-phase unbalanced and reactive compensation equipment; A group coding rule setting module, used for setting a first group coding rule based on different connection modes of components of three-phase unbalanced and reactive compensation equipment; The optimal strategy acquisition module is used to convert the maximum values of different group codes into binary system as the upper limits of different dimensional addresses of the first optimization algorithm, and use the first optimization algorithm to obtain the optimal control strategy for three-phase unbalanced regulation and reactive power compensation in the capacity-adjusting transformer area.
9. An electronic device, comprising: Memory and processor; The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the three-phase unbalanced regulation and reactive power compensation method described in any one of claims 1 to 7 are implemented.
10. A computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the three-phase unbalanced regulation and reactive power compensation method according to any one of claims 1 to 7.