Reactive coordination control method and system

Abstract

The invention discloses a reactive power coordination control method and system. The method comprises the following steps: acquiring a related voltage value of a new energy station; calculating a voltage effective value according to the related voltage value of the new energy station, judging whether the voltage effective value meets a threshold condition and integral counting delay or not, and outputting a corresponding adjustment instruction according to a judgment result; and transmitting the adjustment instruction to the SVG, setting the reactive power reference value to be the maximum value after the SVG receives the adjustment instruction, and sending out the maximum reactive power. According to the invention, the reactive power regulation capability of the SVG is fully utilized, so that the voltage in the station can reach a reasonable degree, repeated ride-through and power oscillation of a new energy unit caused by great voltage drop are avoided, and stable operation of a power system is facilitated. The control method is simple and reliable to implement, can be integrated into a background monitoring system of a new energy station as a functional module, can be flexibly put into and withdrawn as required, and is low in control cost and cost and good in control effect.

Description

Technical Field

[0001] The present invention relates to the technical field of height measurement, and in particular to a reactive power coordinated control method and system. Background Art

[0002] With the construction of new power systems, the proportion of wind and solar power in the system continues to increase, and some regions are gradually dominated by wind and solar power. Compared with the transmission of traditional power, the regional stability characteristics have undergone profound changes. During the transient process of faults, there is interaction between new energy units and the AC system, which affects the stability of the transient power angle transmitted by traditional units; after the integration of new energy, it will affect the machine-grid interaction characteristics of neighboring conventional power sources and DC devices, causing the regional system to have a broadband oscillation risk; the weak dynamic reactive power support capacity of new energy also reduces the strength of the system, and voltage stability and transient overvoltage problems will be more prominent. At the same time, the operation scenarios of new energy are random and changeable, which poses great challenges to the safe and stable operation and risk prevention and control of regional new energy transmission.

[0003] The distance of the new energy collection and transmission line is long, the grid structure is relatively weak and lacks voltage support, showing significant weak grid characteristics, which easily leads to voltage and oscillation stability problems in the new energy collection area. Among them, photovoltaic stations in the southern region occasionally have a new stability problem of repeated fluctuations in active power, causing regional photovoltaic grid disconnection and short-term low-frequency oscillation information alarms for large units in the vicinity, affecting the normal and stable operation of the region. The dynamic reactive power compensation SVG of the new energy station is generally installed on the grid-connected bus of the transmission line. The grid-connected bus voltage level is high (220kV / 110kV, etc.) and is directly connected to the system. The measured voltage is generally relatively stable, and the SVG action times are relatively small; it cannot directly reflect the voltage fluctuations of the low-voltage side 35kV and below voltage levels. Often, when the collector voltage is already lower than the voltage crossing set value of the new energy and repeatedly crosses the low voltage, the SVG installed on the high-voltage side does not act and cannot effectively support the voltage recovery on the low-voltage side. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above existing problems, the present invention is proposed. Therefore, the present invention provides a reactive coordination control method to solve the problem of power oscillation caused by insufficient dynamic reactive support capacity of new energy stations.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a reactive power coordinated control method, comprising:

[0008] Obtain relevant voltage values ​​of new energy stations;

[0009] Calculate the voltage effective value according to the voltage value related to the new energy station, determine whether the voltage effective value meets the threshold condition and the integral counting delay, and output the corresponding adjustment instruction according to the determination result;

[0010] The adjustment instruction is transmitted to the SVG, and the SVG executes a first action after receiving the adjustment instruction.

[0011] As a preferred solution of the reactive power coordinated control method of the present invention, the threshold condition includes:

[0012] If at least three of the effective voltage values ​​of the first device voltage are less than the first voltage threshold and greater than the second voltage threshold, and after T1 delay confirmation, condition 1 is met;

[0013] If the effective value of the second device voltage is less than the third voltage threshold and greater than the fourth voltage threshold, after confirmation by T2 delay, condition 2 is met.

[0014] As a preferred solution of the reactive power coordinated control method of the present invention, the corresponding adjustment instructions are output according to the judgment result, including:

[0015] When both condition 1 and condition 2 are met, the judgment unit outputs adjustment instruction 1;

[0016] When conditions 1 and 2 are still met after delay T3 confirmation, the judgment unit outputs adjustment instruction 2;

[0017] When conditions 1 and 2 are still satisfied after confirmation by delay T4, the judgment unit outputs adjustment instruction 3.

[0018] As a preferred solution of the reactive power coordinated control method of the present invention, the integral counting delay includes:

[0019] The calculation of delays T1, T2, T3, and T4 adopts the integral counting method, and each delay corresponds to a counter;

[0020] When the calculation conditions of delays T1, T2, T3, and T4 are not met continuously for more than 0.2s, the counter is cleared.

[0021] As a preferred solution of the reactive power coordinated control method of the present invention, it also includes:

[0022] When condition 1 is met, the delay counter corresponding to delay T1 is increased by 1, otherwise, the delay counter is decreased by 1;

[0023] When condition 2 is met, the delay counter corresponding to delay T2 is increased by 1, otherwise, the delay counter is decreased by 1;

[0024] When conditions 1 and 2 are met and after delay T3, the delay counter corresponding to delay T3 is +1, otherwise, the delay counter is -1;

[0025] When conditions 1 and 2 are met and delay T4 has passed, the delay counter corresponding to delay T4 is increased by 1, otherwise, the delay counter is decreased by 1.

[0026] As a preferred solution of the reactive power coordinated control method of the present invention, wherein: transmitting the adjustment instruction to the SVG includes:

[0027] The adjustment instruction is transmitted to the SVG by using an interface unit, wherein the interface unit adopts a dual position information transmission method;

[0028] For each adjustment instruction, the interface unit sends two nodes to the SVG controller at the same time. When the values ​​of the two nodes are both 1, the SVG performs the corresponding adjustment operation according to the conditional instruction.

[0029] As a preferred solution of the reactive power coordinated control method of the present invention, the first, second, third and fourth voltage threshold settings include:

[0030] The first voltage threshold is set to the low voltage crossing threshold value of the new energy station;

[0031] The second voltage threshold is set to 0.2 times the rated voltage;

[0032] The third voltage threshold is set to the upper limit of the action voltage threshold of SVG;

[0033] The fourth voltage threshold is set to be the lower limit value of the action voltage threshold of SVG.

[0034] In a second aspect, the present invention provides a system for coordinated reactive power control, comprising:

[0035] A data acquisition module, used to obtain the voltage value of the device;

[0036] A judgment module, used to calculate the voltage effective value according to the device voltage value, judge whether the voltage effective value meets the threshold condition and the integral counting delay, and output a corresponding adjustment instruction according to the judgment result;

[0037] A transmission interface module, used for transmitting the adjustment instruction to the SVG;

[0038] The execution module is used for the SVG to execute a first action after receiving the adjustment instruction.

[0039] In a third aspect, the present invention provides a computing device, comprising:

[0040] Memory and processor;

[0041] 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 reactive power coordinated control method are implemented.

[0042] 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 reactive power coordinated control method.

[0043] Compared with the prior art, the invention has the following beneficial effects: the invention can fully utilize the reactive power regulation capability of SVG by monitoring the bus voltage drop degree of the high-voltage side and the collector of the new energy station, so that the voltage in the station can reach a reasonable level, avoiding the repeated crossing and power oscillation of the new energy units caused by the large voltage drop, which is conducive to the stable operation of the power system. The control method is simple and reliable to implement, and can be integrated into the background monitoring system of the new energy station as a functional module, and can be flexibly put into and withdrawn according to needs, with low control cost, low cost and good control effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0045] Figure 1 It is a schematic diagram of the overall process of the reactive power coordinated control method according to an embodiment of the present invention;

[0046] Figure 2 It is a schematic diagram of the action logic of the reactive power coordinated control method according to an embodiment of the present invention;

[0047] Figure 3 A schematic diagram of the control system structure of a reactive power coordinated control method according to an embodiment of the present invention;

[0048] Figure 4 A typical application diagram of the reactive power coordinated control method according to an embodiment of the present invention;

[0049] Figure 5 It is a schematic diagram of the effect of reactive power coordinated control suppression measures of the reactive power coordinated control 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] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0052] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0053] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0054] At the same time, in the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the system or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0055] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] Example 1

[0057] Reference Figure 1-3, is an embodiment of the present invention, and provides a reactive power coordinated control method, comprising:

[0058] S100: Obtain device voltage value;

[0059] S102: Calculate the voltage effective value according to the device voltage value, determine whether the voltage effective value meets the threshold condition and the integral counting delay, and output the corresponding adjustment instruction according to the determination result;

[0060] S104: transmitting the adjustment instruction to the SVG, and the SVG executes the first action after receiving the adjustment instruction;

[0061] It should be noted that the voltage values ​​of relevant equipment are obtained through step S100, which is the basis for realizing coordinated reactive power control; in step S102, the system will calculate the effective value of the voltage based on these voltage values, and compare it with the preset threshold conditions and integral counting delay, monitor the voltage status in real time, and promptly identify whether the voltage fluctuation has reached the critical condition that may cause power oscillation. Once the effective value of the voltage does not meet the threshold condition or the integral counting delay reaches the preset value, the system will immediately output the corresponding adjustment instruction; in step S104, this adjustment instruction will be quickly transmitted to SVG. As a key dynamic reactive power compensation device, SVG will immediately set the reactive reference value to the maximum value and emit the maximum reactive power after receiving the adjustment instruction. This rapid response mechanism effectively supports the voltage stability on the low-voltage side and prevents system power oscillation caused by new energy units frequently entering and exiting the low-voltage ride-through state.

[0062] In the embodiment of the present application, the device in the above step S100 includes a first device and a second device;

[0063] In an optional embodiment, the first device and the second device may be a collector, a high-voltage side device, a transformer, a reactive power supplement device, etc.;

[0064] In the embodiment of the present application, the collector is selected as the first device, and the high-voltage side device is selected as the second device for subsequent description.

[0065] In the embodiment of the present application, the above step S102 includes sub-steps A1-A4;

[0066] In A1: Calculate the voltage effective value according to the voltage value of the equipment. The voltage effective value calculation method may include full-wave Fourier algorithm, sliding average method and discrete sampling integration method, etc.;

[0067] In a possible embodiment, if the full-wave Fourier algorithm is selected, the process of obtaining the effective value of the voltage is: sampling the AC voltage, uniformly sampling 24 points within each power frequency cycle, such as 50 Hz corresponding to 0.02 seconds, and the sampling frequency must be high enough to capture the changes in the voltage signal; digital filtering is performed on the sampled voltage data to remove high-frequency noise and interference, and improve the accuracy and reliability of the data; Fourier transform is performed on the filtered voltage data to obtain the frequency spectrum information of the voltage signal, and the amplitude and phase information of the fundamental component are extracted; according to the amplitude of the fundamental component, the effective value of the voltage is calculated using the definition of the effective value of the voltage, that is, the voltage value of the alternating current that produces the same thermal effect as the direct current.

[0068] In a possible embodiment, if the sliding average method is selected, the process of obtaining the effective value of the voltage is: continuously sampling the AC voltage to obtain a voltage data sequence containing multiple sampling points; setting a sliding window of a fixed length, which contains a certain number of sampling points; continuously moving the sliding window, and calculating the average value of the voltage values ​​of all sampling points in the window at each window position. This average value can be regarded as an approximation of the effective value of the voltage at the current moment.

[0069] In A2: determine whether the voltage effective value meets the threshold condition, the threshold condition includes:

[0070] If at least three of the effective voltage values ​​of the first device voltage are less than the first voltage threshold and greater than the second voltage threshold, and after T1 delay confirmation, condition 1 is met;

[0071] It should be noted that the number of collector lines is N. When N≤3, the actual number of connected lines is N; when N>3, 3 lines are taken;

[0072] If the effective value of the voltage of the second device is less than the third voltage threshold and greater than the fourth voltage threshold, after confirmation by T2 delay, condition 2 is met;

[0073] In the embodiment of the present application, the first voltage threshold is set to the low voltage crossing threshold value of the new energy station; the second voltage threshold is set to 0.2 times the rated voltage; the third voltage threshold is set to the upper limit of the action voltage threshold of SVG; the fourth voltage threshold is set to the lower limit of the action voltage threshold of SVG;

[0074] In the embodiment of the present application, condition 1 is expressed by the formula:

[0075] U1<K11,U1>K12,t1≥T1

[0076] Among them, U1 is the effective value of voltage, K11 is the first voltage threshold, K12 is the second voltage threshold, t1 is the actual time, and T1 is the set delay time;

[0077] In the embodiment of the present application, condition 2 is expressed by the formula:

[0078] U2<K21,U2>K22,t2≥T2

[0079] Among them, U1 is the effective value of voltage, K21 is the third voltage threshold, K22 is the fourth voltage threshold, t2 is the actual time, and T2 is the set delay time.

[0080] In A3: determine whether the voltage effective value meets the integral counting delay, the integral counting delay includes delays T1, T2, T3, and T4; the calculation of delays T1, T2, T3, and T4 adopts the integral counting method, and each delay corresponds to a counter; when the calculation conditions of delays T1, T2, T3, and T4 are not met for more than 0.2s continuously, the counter is cleared;

[0081] In the embodiment of the present application, the integral counting is specifically as follows: when condition 1 is met, the delay counter corresponding to delay T1 is +1, otherwise, the delay counter is -1; when condition 2 is met, the delay counter corresponding to delay T2 is +1, otherwise, the delay counter is -1; when conditions 1 and 2 are met, and after delay T3, the delay counter corresponding to delay T3 is +1, otherwise, the delay counter is -1; when conditions 1 and 2 are met, and after delay T4, the delay counter corresponding to delay T4 is +1, otherwise, the delay counter is -1.

[0082] In A4: outputting corresponding adjustment instructions according to the judgment result;

[0083] In the embodiment of the present application, the adjustment instruction includes:

[0084] ① When both condition 1 and condition 2 are met, the judgment unit outputs adjustment instruction 1;

[0085] ② When conditions 1 and 2 are still met after delay T3 confirmation, the judgment unit outputs adjustment instruction 2;

[0086] ③ When conditions 1 and 2 are still met after delay T4 confirmation, the judgment unit outputs adjustment instruction 3;

[0087] In the embodiment of the present application, the first action corresponding to the adjustment instruction 1 is the reactive coordination action 1; the first action corresponding to the adjustment instruction 2 is the reactive coordination action 2; the first action corresponding to the adjustment instruction 3 is the reactive coordination action 3; specifically expressed as follows Figure 2 Action logic diagram;

[0088] In another embodiment, the adjustment instruction 1 may be: when the voltage fluctuation of the new energy station exceeds the normal range, immediately start the reactive power compensation device to adjust the reactive power output to stabilize the voltage;

[0089] In another embodiment, the adjustment instruction 2 may be: if the output power of the new energy station is continuously higher than the grid demand by 10% of the rated power, the output power of the generator in the station is reduced to match the grid demand; if the output power of the new energy station is continuously lower than the grid demand by 90% of the rated power, the output power of the generator in the station is increased or the standby generator set is started to meet the grid demand.

[0090] In another embodiment, the adjustment instruction 3 may be: when the new energy station detects that the grid frequency is abnormal and deviates from the range of 50Hz±0.2Hz, the generator operating parameters in the station are immediately adjusted to assist the grid in maintaining frequency stability.

[0091] The adjustment command is transmitted to the SVG. After receiving the adjustment command, the SVG sets the reactive power reference value to the maximum value and generates the maximum reactive power.

[0092] In the embodiment of the present application, the above step S104 further includes:

[0093] In the embodiment of the present application, the adjustment instruction is transmitted to the SVG by using the interface unit, and the interface unit adopts a dual position information transmission method;

[0094] In an optional embodiment, the interface unit may be an optical fiber interface or a network interface, etc.; the transmission mode may be serial communication of dual-position information and network communication of dual-position information, etc.;

[0095] In a possible embodiment, when the interface unit selects the optical fiber interface as the transmission medium and the transmission mode is serial communication of dual-position information, the specific process of using the interface unit to transmit the adjustment instruction to the SVG is: encoding the adjustment instruction into a serial data stream, and embedding the dual-position information in the data stream, including a start bit, a stop bit, a check bit, and additional position or status information bits, etc.; sending the encoded data stream to the SVG through the optical fiber interface, the SVG controller receives and parses the data stream, and performs corresponding adjustment operations according to the parsing results and the dual-position information.

[0096] In a possible embodiment, when the interface unit selects a network interface as a transmission medium and the transmission method is also network communication of dual-position information, the process of using the interface unit to transmit the adjustment instruction to the SVG is: encapsulating the adjustment instruction into a network data packet, and embedding the dual-position information in the data packet, including a flag bit in the data packet header, priority information, etc.; sending the encapsulated data packet to the network where the SVG is located through the network interface, the SVG controller receives and parses the data packet, and performs corresponding adjustment operations according to the parsing results and the dual-position information.

[0097] In the embodiment of the present application, for each adjustment instruction, the interface unit simultaneously sends two nodes to the SVG controller, and when the values ​​of the two nodes are both 1, the SVG performs the corresponding adjustment operation according to the conditional instruction;

[0098] It should be noted that the operation process of the present invention is as follows Figure 3 As shown, the single-phase voltage of the collector and the three-phase voltage on the high-voltage side are collected by the collection unit, and the collected voltage is judged by the judgment unit to obtain a control command, that is, the above-mentioned adjustment instruction, and then the message or node is transmitted to the execution unit through the interface unit. The execution unit includes execution unit 1, execution unit 2 and execution unit 3. The execution unit adjusts and executes corresponding actions according to the control command;

[0099] It should also be noted that by real-time monitoring of the voltage values ​​of the high-voltage side and the collector of the new energy station, the effective value of the voltage is calculated, and the corresponding adjustment instructions are output according to the judgment results; the interface unit is then used to quickly and accurately transmit the precise adjustment instructions to the SVG; after receiving the instructions, the SVG can respond immediately and set the reactive reference value to the maximum value, and emit the maximum reactive power, thereby achieving rapid response and precise adjustment of the reactive power demand of the power grid; the present invention not only enhances the voltage stability of the new energy station, avoids the repeated crossing and power oscillation problems of the new energy units caused by the sharp drop in voltage, but also improves the operation efficiency and power generation efficiency of the new energy station; at the same time, the control method is simple and reliable to implement, easy to integrate into the background monitoring system of the new energy station, and has low control cost and low cost, and has high economic and social benefits.

[0100] The above is a schematic scheme of a reactive coordination control method of this embodiment. It should be noted that the technical scheme of the reactive coordination control system and the technical scheme of the reactive coordination control method described above belong to the same concept, and the details of the technical scheme of the reactive coordination control system in this embodiment that are not described in detail can all be referred to the description of the technical scheme of the reactive coordination control method described above.

[0101] The reactive power coordinated control system in this embodiment includes:

[0102] A data acquisition module, used to obtain the voltage value of the device;

[0103] A judgment module is used to calculate the voltage effective value according to the voltage value of the device, judge whether the voltage effective value meets the threshold condition and the integral counting delay, and output the corresponding adjustment instruction according to the judgment result;

[0104] A transmission interface module, used for transmitting the adjustment instruction to the SVG;

[0105] The execution module is used for the SVG to execute the first action after receiving the adjustment instruction.

[0106] This embodiment further provides a computing device, which is applicable to reactive power coordinated control, and includes:

[0107] Memory and processor; the memory is used to store computer executable instructions, and the processor is used to execute computer executable instructions to implement the reactive power coordinated control method proposed in the above embodiment.

[0108] This embodiment further provides a storage medium on which a computer program is stored. When the program is executed by a processor, the method for realizing reactive power coordinated control as proposed in the above embodiment is implemented.

[0109] The storage medium proposed in this embodiment and the method for realizing reactive coordinated control 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.

[0110] 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.

[0111] Example 2

[0112] Reference Figure 4-5 , which is an embodiment of the present invention, provides a reactive power coordinated control method. In order to verify its beneficial effects, comparison results of two schemes are provided.

[0113] Take a photovoltaic substation as an example. Figure 4 As shown in the figure, the installed capacity of the photovoltaic power station is 240MW, with a total of 12 35kV collectors, and the rated capacity of the photovoltaic power generation unit under each collector is 20MW; two 50MVar SVGs are configured on the 220kV bus side of the station, and the upper and lower limits of the transient control of SVG are UsvgH=1.05pu, UsvgL=0.98pu;

[0114] Under the condition of high-power generation of the photovoltaic power station, after a fault disturbance occurs in the adjacent area, the voltage of the collector line of the photovoltaic power station can drop to around 0.9pu. Due to the low voltage ride-through threshold constant U1set=0.9Un., the photovoltaic unit repeatedly enters low voltage ride-through, and the active power fluctuates repeatedly; but at this time, the voltage on the photovoltaic 220kV side fluctuates slightly within 1.0pu, and the SVG transient control is not triggered. It has been in the pre-fault control mode. The SVG cannot respond to the grid-connected voltage at the end of the collector line.

[0115] The coordinated control method proposed in the present invention is applied, the reactive coordinated control method is integrated into the monitoring system at the station end, and the signal is remotely transmitted to the control devices of the two SVGs through the universal device of the network transfer node.

[0116] Set K11=0.92Un, K12=0.2Un, T1=4s; K21=0.98Un, K22=1.05Un, T2=4s, T3=3s, T4=5s.

[0117] First, a real-time simulator is used to simulate the on-site operating conditions. It can be seen that the collector line has power oscillations, such as Figure 5 As shown by the black curve, if the reactive power coordination control method of the present invention is put into use, after about 4 seconds, the reactive power coordination strategy action 1 is executed, and #1SVG is quickly increased from about -5MVar to about 48MVar, and the photovoltaic grid-connected point voltage is increased to about 0.94pu. Figure 5 As shown by the red curve, the photovoltaic industry has left the low voltage ride-through action area, and the phenomenon of repeated low voltage ride-through and large power fluctuations has been effectively suppressed.

[0118] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. 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.

Claims

1. A reactive power coordinated control method, characterized in that: include: Get the device voltage value; Calculate the voltage effective value according to the device voltage value, determine whether the voltage effective value meets the threshold condition and the integral counting delay, and output a corresponding adjustment instruction according to the determination result; The adjustment instruction is transmitted to the SVG, and the SVG executes a first action after receiving the adjustment instruction.

2. The reactive power coordinated control method according to claim 1, characterized in that: Threshold conditions include, If at least three of the effective voltage values ​​of the first device voltage are less than the first voltage threshold and greater than the second voltage threshold, and after T1 delay confirmation, condition 1 is met; If the effective value of the second device voltage is less than the third voltage threshold and greater than the fourth voltage threshold, after confirmation by T2 delay, condition 2 is met.

3. The reactive power coordinated control method according to claim 1 or 2, characterized in that: According to the judgment results, the corresponding adjustment instructions are output, including: When both condition 1 and condition 2 are met, the judgment unit outputs adjustment instruction 1; When conditions 1 and 2 are still met after delay T3 confirmation, the judgment unit outputs adjustment instruction 2; When conditions 1 and 2 are still satisfied after confirmation by delay T4, the judgment unit outputs adjustment instruction 3.

4. The reactive power coordinated control method according to claim 3, characterized in that: The integral counting delay includes: The calculation of delays T1, T2, T3, and T4 adopts the integral counting method, and each delay corresponds to a counter; When the calculation conditions of delays T1, T2, T3, and T4 are not met continuously for more than 0.2s, the counter is cleared.

5. The reactive power coordinated control method according to claim 4, characterized in that: Also includes, When condition 1 is met, the delay counter corresponding to delay T1 is increased by 1, otherwise, the delay counter is decreased by 1; When condition 2 is met, the delay counter corresponding to delay T2 is increased by 1, otherwise, the delay counter is decreased by 1; When conditions 1 and 2 are met and after delay T3, the delay counter corresponding to delay T3 is +1, otherwise, the delay counter is -1; When conditions 1 and 2 are met and delay T4 has passed, the delay counter corresponding to delay T4 is increased by 1, otherwise, the delay counter is decreased by 1.

6. The reactive power coordinated control method according to claim 3, characterized in that: Transmitting the adjustment instruction to the SVG comprises, The adjustment instruction is transmitted to the SVG by using an interface unit, wherein the interface unit adopts a dual position information transmission method; For each adjustment instruction, the interface unit sends two nodes to the SVG controller at the same time. When the values ​​of the two nodes are both 1, the SVG performs the corresponding adjustment operation according to the conditional instruction.

7. The reactive power coordinated control method according to claim 6, characterized in that: The first, second, third and fourth voltage threshold settings include, The first voltage threshold is set to the low voltage crossing threshold value of the new energy station; The second voltage threshold is set to 0.2 times the rated voltage; The third voltage threshold is set to the upper limit of the action voltage threshold of SVG; The fourth voltage threshold is set to be the lower limit value of the action voltage threshold of SVG.

8. A reactive power coordinated control system, characterized in that: include, A data acquisition module, used to obtain the voltage value of the device; A judgment module, used to calculate the voltage effective value according to the device voltage value, judge whether the voltage effective value meets the threshold condition and the integral counting delay, and output a corresponding adjustment instruction according to the judgment result; A transmission interface module, used for transmitting the adjustment instruction to the SVG; The execution module is used for the SVG to execute a first action after receiving the adjustment instruction.

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 reactive power coordinated control 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 reactive power coordinated control method according to any one of claims 1 to 7.

Images