A bidirectional regulation method for voltage compensation of distribution lines

Abstract

The present invention belongs to the technical field of voltage compensation control, and specifically discloses a bidirectional adjustment method for distribution line voltage compensation. The method collects voltage data of each set node in the distribution line in real time and analyzes voltage change characteristics, effectively solving the current problem of insufficient consideration of the specific transmission line status, fully considering indicators such as voltage fluctuation laws, ensuring the adaptability of subsequent voltage compensation mechanism settings, and calculating the voltage exceeding the allowable degree according to the voltage change characteristics, and designing an excess redundant compensation factor. At the same time, it is judged whether the voltage of the distribution line exceeds the allowable range in combination with the excess redundant compensation factor. The risk points of voltage fluctuation can be identified in advance, which is convenient for taking measures to prevent voltage fluctuations in time. In addition, by determining the compensation setting nodes and compensation methods, the deficiency of the current compensation mechanism setting being relatively single is solved, and the flexibility of the voltage compensation setting is guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of voltage compensation control, and in particular, relates to a bidirectional regulation method for voltage compensation of a distribution line. Background Art

[0002] With the rapid development of modern industry and society, the electrical equipment at the user end is becoming more and more sophisticated and complex. Even a short-term voltage fluctuation may lead to serious consequences such as production equipment failure and data loss. Therefore, in order to meet the strict requirements of these high-end users for power quality, it is necessary to accurately adjust the distribution line voltage in both directions.

[0003] Prior art, such as a three-phase electromagnetic series transmission line bidirectional voltage adaptive regulation device disclosed in the Chinese invention patent application with application number 202110051727.2, includes an electromagnetic bidirectional transmission line voltage regulation circuit and a transmission line voltage compensation control part. The closed iron core magnetic circuit realizes the power conversion between the series voltage regulating winding and the parallel energy extraction winding, establishes the voltage and polarity between the taps of the secondary regulating winding, and then increases, decreases and adjusts the polarity of the series voltage regulating winding voltage through the selection of the on-load tap changer. The primary winding is connected in parallel to the power supply and distribution line, and the secondary regulating winding is connected in series between the power supply and distribution line and the regulated object. It is suitable for occasions with distribution stations with a large power supply radius and any capacity ratio combination of distributed power sources, and solves the problem of voltage exceeding the limit at the end of long distribution lines caused by the high penetration rate of distributed power sources.

[0004] Another example of the prior art is a low-voltage distribution network power quality comprehensive management device disclosed in the Chinese invention patent application with application number 201510262363.7, which includes a control module, a voltage regulation module and a reactive compensation module. The control module controls the voltage regulation module and the reactive compensation module respectively, and the input line of the low-voltage distribution network is connected to the output line of the low-voltage distribution network through the voltage regulation module and the reactive compensation module. The voltage regulation module is a voltage bidirectional regulation module. It effectively avoids voltage instability caused by voltage fluctuations by utilizing voltage compensation hierarchical bidirectional regulation and the intelligent delay function of the composite switch. The composite switch in the reactive compensation module is used to reduce the current impact of the traditional contactor switching, reduce the loss of the system, and ensure the safety of the device. At the same time, the human-machine interface is used to make it easy to operate and maintain, and the remote transmission method is used to further improve the monitoring capability of the power grid.

[0005] With regard to the above two technical solutions, it is obvious that the bidirectional regulation of distribution line voltage compensation still has the following problems: 1. Insufficient consideration of the specific state of the transmission line, such as the voltage fluctuation law, etc., which makes the adaptability and accuracy of the compensation mechanism still have certain deviations, and thus cannot guarantee the effectiveness and efficiency of compensation.

[0006] 2. The compensation mechanism is relatively simple and not very flexible. There is no detailed analysis of specific compensation needs and no diversified selection of compensation methods. As a result, voltage compensation cannot be performed quickly and reliably, and the impact of voltage fluctuations and deviations cannot be reduced. Summary of the invention

[0007] In view of this, in order to solve the problems raised in the above background technology, a bidirectional regulation method for distribution line voltage compensation is proposed.

[0008] The purpose of the present invention can be achieved through the following technical solutions: The present invention provides a bidirectional adjustment method for distribution line voltage compensation, including: installing high-precision voltage sensors, temperature sensors and bidirectional voltage compensation devices at each set node of the distribution line.

[0009] A real-time communication network is established to connect the sensor, the compensation device and the central controller for communication.

[0010] The voltage data and temperature data of each node in the distribution line are collected in real time, and the real-time collected voltage data and temperature are transmitted to the central controller through the communication network.

[0011] Import the past operation monitoring data of the distribution line and analyze the voltage change characteristics based on the real-time collected voltage.

[0012] According to the voltage change characteristics, determine whether the voltage of the distribution line exceeds the allowable range. If the voltage exceeds the allowable range, proceed to the next step.

[0013] Determine the compensation setting node and compensation method.

[0014] The central controller sends a control instruction to the bidirectional voltage compensation device and performs adaptive voltage compensation according to the determined compensation setting node and compensation mode and the voltage data of the compensation setting node collected in real time.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention effectively solves the current problem of insufficient consideration of the specific state of the transmission line by collecting the voltage data of each node set in the distribution line in real time and analyzing the voltage change characteristics. It fully considers indicators such as the voltage fluctuation law, ensures the adaptability and accuracy of the subsequent voltage compensation mechanism setting, and at the same time ensures the effectiveness and efficiency of voltage compensation.

[0016] (2) The present invention calculates the voltage exceeding the permissible degree according to the voltage variation characteristics, designs the excess redundant compensation factor, and judges whether the voltage of the distribution line exceeds the permissible range in combination with the excess redundant compensation factor. The risk points of voltage fluctuation can be identified in advance, which facilitates timely measures to prevent voltage fluctuations. At the same time, it makes up for the lack of current environmental adaptability, breaks the deficiency that the current compensation mechanism is greatly constrained by the environment, and ensures the stability of subsequent voltage compensation.

[0017] (3) The present invention effectively solves the problem of the current single compensation mechanism setting by determining the compensation setting nodes and compensation methods, ensures the flexibility of voltage compensation setting, realizes detailed analysis of specific compensation requirements and diversified selection of compensation methods, facilitates fast and reliable voltage compensation, and can effectively reduce the impact of voltage fluctuations and deviations, thereby ensuring the safety and reliability of distribution line operation and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing 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.

[0019] Figure 1 The present invention is a schematic flow chart of the steps for implementing the method.

[0020] Figure 2 It is a schematic diagram of communication network transmission of the present invention.

[0021] Figure 3 The figure is a schematic diagram of the structure of the bidirectional voltage compensation device of the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] See also Figure 1 As shown, the present invention provides a bidirectional regulation method for distribution line voltage compensation, the method comprising: S1, installing a high-precision voltage sensor, a temperature sensor and a bidirectional voltage compensation device at each set node of the distribution line.

[0024] See also Figure 2As shown, S2, building a real-time communication network to connect the sensor, the compensation device and the central controller for communication.

[0025] S3. Collect voltage data and temperature data of each node in the distribution line in real time, and transmit the real-time collected voltage data and temperature to the central controller through the communication network.

[0026] S4. Import the past operation monitoring data of the distribution line and analyze the voltage change characteristics based on the real-time collected voltage.

[0027] S5. According to the voltage variation characteristics, determine whether the voltage of the distribution line exceeds the allowable range. If the voltage exceeds the allowable range, proceed to the next step.

[0028] S6. Determine the compensation setting node and compensation method.

[0029] S7. The central controller sends a control instruction to the bidirectional voltage compensation device according to the determined compensation setting node and compensation mode and the voltage data of the compensation setting node collected in real time, and performs adaptive voltage compensation.

[0030] Specifically, it should be added in step S1 that the setting nodes of the distribution line include substations, important load points, distributed power source access points, etc. in a specific embodiment.

[0031] It is also necessary to refer to Figure 3 As shown, the bidirectional voltage compensation device is integrated with components such as multiple capacitor groups, multiple reactor groups, on-load tap-changing transformers, dynamic voltage restorers, and static VAR generators.

[0032] Specifically, it should be added about step S2 that, in a specific embodiment, when building a real-time communication network, wired communication such as Ethernet, RS-485, or wireless communication such as 4G / 5G and LoRa can be selected.

[0033] Specifically, in step S3, the voltage data is the monitored voltage value at each monitoring time point, and the temperature data is the monitored temperature value at each monitoring time point.

[0034] Specifically, regarding the analysis of voltage change characteristics in step S4, it includes: S41, extracting the monitoring voltage value at each monitoring time point from the voltage data, grouping the monitoring time points into monitoring time windows according to the set monitoring time interval, and calculating the voltage amplitude and frequency of each set node in each monitoring time window.

[0035] S42, constructing a voltage amplitude change curve of each setting node with the monitoring time window as the horizontal coordinate and the voltage amplitude as the vertical coordinate, and calculating the slope of the voltage amplitude change curve as the voltage amplitude change rate.

[0036] S43. Construct the frequency change curve of each setting node in the same way as the voltage amplitude change curve, calculate the slope of the frequency change curve as the frequency change rate, and extract the number of fluctuation points of the frequency change curve, and divide it by the number of monitoring time windows, and use the ratio as the frequency fluctuation degree.

[0037] S44. Extract the voltage amplitude and frequency of each setting node in each monitoring time window on each monitoring day from the past operation monitoring data, and define the voltage change acceptance factor of each setting node.

[0038] S45. The voltage amplitude change rate, frequency change rate, frequency fluctuation and voltage change acceptance factor of each set node are taken as voltage change characteristics.

[0039] Understandably, it should be added to step S41 that the monitoring time interval can be specifically set to 3 seconds.

[0040] It can be understood that the specific calculation process of the voltage amplitude in step S41 is: the monitored voltage values ​​of each set node at each monitoring time point in each monitoring time window are composed into instantaneous value sample data, and the root mean square value of these instantaneous value sample data is calculated. For a sine wave, the relationship between the root mean square value and the amplitude is: , is the voltage amplitude, is the calculated RMS value. For example, the RMS value of the AC voltage of a certain node in a monitoring time window is 220, and its amplitude is .

[0041] It can be understood that the frequency calculation process in step S41 is as follows: the monitored voltage value at each monitoring time point is imported into the oscilloscope, and the ratio of the number of waveforms to the duration is used as the frequency.

[0042] It can be understood that the calculation of the slope in step S41 is the slope of the regression line corresponding to the curve, which can be directly calculated by an image processing tool.

[0043] Understandably, the voltage change acceptance factor of each setting node defined in step S44 includes: A1, extracting the rated voltage range and the maximum allowable voltage fluctuation range at each setting node from past operation monitoring data, and integrating them to obtain the reference acceptance voltage range of each setting node.

[0044] A2. Based on the voltage amplitude in each monitoring time window on each monitoring day, calculate the actual voltage fluctuation range of each set node on each monitoring day.

[0045] A3. Extract the maximum frequency fluctuation range allowed at each setting node from the past operation monitoring data.

[0046] A4. Calculate the actual frequency fluctuation range of each monitoring day in the same way as the actual voltage fluctuation range, and confirm the deviation monitoring day of each setting node and the deviation factor of each deviation monitoring day accordingly.

[0047] A5. Extract the abnormal event set of the voltage fluctuation equipment corresponding to each setting node, and extract the occurrence date and abnormal level of each abnormal event from the abnormal event set.

[0048] A6. If a deviation monitoring day corresponding to a setting node coincides with the sending date of an abnormal event, the fluctuation deviation day is recorded as the target day, and the number of target days is counted.

[0049] A7. Set the abnormal matching factor of each setting node, denoted as , Indicates setting the node number. .

[0050] A8. Compare the target number of each setting node with its monitoring number of days to obtain the abnormal occurrence ratio of each setting node, which is recorded as .

[0051] A9. Define the voltage change acceptance factor for each setting node , .

[0052] It should be added about step A1 that the source of the rated voltage range at the node set in the above can come from the nameplate parameter record of the equipment, the equipment ledger information, and the equipment-related data continuously collected by the monitoring system during the operation of the equipment. For example, for the transformer in the substation, the value of the rated voltage will be clearly marked on its nameplate, and the monitoring system will also record these basic parameter information during the initial connection of the equipment and subsequent operation.

[0053] It should be added about step A1 that the source of the maximum voltage fluctuation range allowed at the setting node mentioned above comes from the technical specification provided by the equipment manufacturer, which will clearly indicate the upper and lower limits of the voltage fluctuation allowed under normal operation of the equipment. On the other hand, the voltage fluctuation range that the equipment can actually adapt to can be summarized through long-term monitoring of the equipment's operating status and fault record analysis. For example, a precision electronic equipment manufacturer stipulates that the allowable voltage fluctuation range of its equipment is ±5% based on the rated voltage, and through actual monitoring, it is found that at the setting node where the equipment is located, even if the voltage fluctuation reaches ±6%, the equipment can still operate normally for a period of time, but some performance degradation may occur. In a specific embodiment, these factors can be comprehensively considered to determine the actual maximum allowable voltage fluctuation range.

[0054] In a specific embodiment, when extracting the rated voltage range and the maximum allowable voltage fluctuation range at each setting node, it should be noted that for each setting node, the past operation monitoring data is carefully screened to find the rated voltage related records of the corresponding electrical equipment. For some more complex electrical systems, there may be many different types of electrical equipment such as motors, capacitors, switch cabinets, etc., working together at the node. At this time, the rated voltage range of each device needs to be extracted separately.

[0055] The basic principle of integration in step A1 is to consider that the equipment must work normally within the rated voltage range and be able to withstand a certain degree of voltage fluctuation. Therefore, based on the rated voltage range and combined with the maximum allowable voltage fluctuation range, the final reference acceptance voltage range is determined through mathematical calculations.

[0056] For example, the specific integration example of integrating the reference acceptance voltage range of each setting node is as follows: 1) For a device with a rated voltage given as a single value, such as a rated voltage of 380V, if the maximum allowable voltage fluctuation range is ±5%, the upper and lower limits of the voltage fluctuation are first calculated. The lower limit is: 380V×(1-5%)=361V.

[0057] The upper limit is: 380V×(1+5%)=399V. Therefore, the reference acceptable voltage range of the device's installation node is 361V-399V.

[0058] 2) For equipment with rated voltage given in voltage range, such as the rated voltage range is 220V-240V, the upper and lower limits of fluctuation for each endpoint are calculated separately using the same calculation method for the rated voltage given as a single value.

[0059] For the lower limit of 220V, the lower limit of fluctuation is: 220V×(1-5%)=209V, and the upper limit of fluctuation is: 220V×(1+5%)=231V.

[0060] For the upper limit of 240V, the lower limit of fluctuation is: 240V×(1-5%)=228V. The upper limit of fluctuation is: 240V×(1+5%)=252V. In summary, the reference acceptance voltage range of the node where the device is located is 209V-252V.

[0061] 3) When there are multiple electrical devices at a setting node, for example, at a certain node, the reference accepted voltage range of device A is 361V-399V, and the reference accepted voltage range of device B is 370V-400V, then the reference accepted voltage range of the node is 370V-399V.

[0062] It should be explained that when there are multiple electrical devices at a setting node, the intersection of the reference acceptance voltage ranges of each electrical device needs to be taken as the final reference acceptance voltage range of the setting node. This is because only when the voltage is within the range acceptable to all electrical devices can the electrical devices of the entire node operate normally.

[0063] It is also necessary to explain that by comprehensively and accurately extracting and integrating the reference acceptance voltage range of each setting node from past operation monitoring data, this will provide an important reference basis for subsequent voltage monitoring, regulation and stable operation of the power system.

[0064] It should be added about step A2 that the voltage fluctuation range is the difference between the maximum voltage amplitude and the minimum voltage amplitude.

[0065] Regarding the confirmation of each deviation monitoring day for each setting node as described in step A4, it includes: for each setting node, on each monitoring day, the actual voltage fluctuation range of the setting node on that day is overlapped and compared with the reference acceptance voltage range of the node, and the ratio of the length of the overlap range to the length of the actual voltage fluctuation range is calculated as the voltage amplitude change consistency.

[0066] For each setting node and each monitoring day, the actual frequency fluctuation range of the setting node on each monitoring day is overlapped and compared with the maximum frequency fluctuation range allowed by the electrical equipment at the setting node, and the frequency change consistency is calculated in the same way as the voltage amplitude change consistency.

[0067] The existence of a voltage amplitude change consistency or a frequency change consistency that is less than a set reference change consistency is used as a fluctuation deviation certification condition.

[0068] If a setting node meets the fluctuation deviation authentication condition on a certain monitoring day, the monitoring day is recorded as the deviation monitoring day, so as to obtain the deviation monitoring days of each setting node.

[0069] It should be added that the specific value of the reference change fit can be 0.5.

[0070] The specific confirmation process of the deviation factor of each deviation monitoring day described in step A4 includes: if on a certain deviation monitoring day, only the voltage amplitude change consistency is less than the set reference change consistency, Serves as the deviation factor for this deviation monitoring day.

[0071] If the frequency change consistency is less than the set reference change consistency on a certain deviation monitoring day, Serves as the deviation factor for this deviation monitoring day.

[0072] If the voltage amplitude change consistency and frequency change consistency of a certain deviation monitoring day are both less than the set reference change consistency, The deviation factor of the deviation monitoring day is used as the deviation factor of the deviation monitoring day, thereby obtaining the deviation factor of each deviation monitoring day.

[0073] It should be added that the deviation factor for each deviation monitoring day is or or ,in, , in a specific embodiment, The value can be 0.8. The value can be 0.4. The value can be 0.2.

[0074] The abnormal matching factor of each setting node set in step A7 includes: matching and obtaining the reference abnormal level of each setting node corresponding to each target day based on the reference abnormal level of each deviation factor set in advance.

[0075] If the reference abnormality level of a certain setting node on a certain target day is the same as the abnormality level of the corresponding abnormal event of the setting node on the target day, the target day is recorded as an abnormal match day, otherwise it is recorded as an abnormal deviation day.

[0076] If the matching anomaly level of a setting node on the abnormal deviation day is higher than the abnormal level of the abnormal event, 0 is used as the abnormal interference factor.

[0077] If the matching anomaly level of a certain setting node on the abnormal deviation day is lower than the abnormal level of the abnormal event, the number of interval abnormal levels between the matching anomaly level and the abnormal level of the abnormal event is counted and recorded as ,Will as abnormal interference factors.

[0078] The average abnormal interference factor of each setting node on each abnormal deviation day is calculated to obtain the average abnormal interference factor of each setting node, which is recorded as .

[0079] The number of abnormal matching days of each setting node is counted and compared with the number of target days to obtain the abnormal matching ratio of each setting node, which is recorded as , set the abnormal fit factor of each setting node , , is a natural constant.

[0080] Exemplarily, when setting the abnormal matching factor of each setting node, the specific example setting process taking a setting node as an example includes the following steps: W1. Define the abnormal level of the abnormal event: abnormal level 1 corresponds to a minor abnormality, abnormal level 2 corresponds to a moderate abnormality, and abnormal level 3 corresponds to a severe abnormality.

[0081] W2. Set the mapping relationship between the deviation factor and the reference anomaly level: deviation factor ≤ 0.2 corresponds to a reference anomaly level of 3, 0.2 < deviation factor < 0.5 corresponds to a reference anomaly level of 2, and 0.5 ≤ deviation factor ≤ 1.0 corresponds to a reference anomaly level of 1.

[0082] Assume that the following data is available, as shown in Table 1.

[0083] Table 1 Schematic diagram of some data on the target day

[0084]

[0085] W3. According to the deviation factor, the reference abnormality level is matched, as shown in Table 2.

[0086] Table 2 Schematic diagram of matching data with reference to abnormal level

[0087]

[0088] W4. Compare and match the reference event abnormality level with the actual abnormality level, and set it step by step according to the setting process of the abnormal matching factor described in the present invention.

[0089] The embodiment of the present invention effectively solves the current problem of insufficient consideration of the specific state of transmission lines by collecting voltage data of each node set in the distribution line in real time and analyzing the voltage change characteristics. It fully considers indicators such as the voltage fluctuation law, ensures the adaptability and accuracy of the subsequent voltage compensation mechanism setting, and at the same time ensures the effectiveness and efficiency of voltage compensation.

[0090] Specifically, regarding the determination of whether the voltage of the distribution line exceeds the allowable range in step S5, it includes: S51, based on the voltage change characteristics, calculating the voltage excess redundancy compensation factor of each setting node, and accordingly correcting the maximum frequency fluctuation range and maximum voltage fluctuation range allowed by the electrical equipment at each setting node to obtain the corrected maximum frequency fluctuation range and maximum voltage fluctuation range.

[0091] S52: For each setting node, in each monitoring time window, check whether its voltage amplitude and frequency are both within the corrected maximum voltage fluctuation range and maximum frequency fluctuation range.

[0092] S53. If the voltage amplitude and frequency of each setting node in each monitoring time window are within the corrected maximum voltage fluctuation range and maximum frequency fluctuation range, it is judged that the voltage of the distribution line does not exceed the allowable range; otherwise, it is judged that the voltage of the distribution line exceeds the allowable range.

[0093] Furthermore, the calculation of the voltage excess redundancy compensation factor of each setting node in step S51 includes: recording the voltage amplitude change rate, frequency change rate, and frequency fluctuation of each setting node as , and .

[0094] Calculate the voltage excess redundancy compensation factor for each setting node , , and They are the reference change rate, frequency fluctuation and voltage change acceptance factor.

[0095] In a specific embodiment, the reference change rate can be set to a value of 0.1, the reference frequency fluctuation can be set to a value of 0.2, and the reference voltage change acceptance factor can be set to a value of 0.3.

[0096] The embodiment of the present invention calculates the voltage excess allowable degree according to the voltage variation characteristics, designs the excess redundant compensation factor, and judges whether the voltage of the distribution line exceeds the allowable range in combination with the excess redundant compensation factor. It can identify the risk points of voltage fluctuation in advance, facilitate timely measures to prevent voltage fluctuations, and make up for the lack of current environmental adaptability, break the deficiency that the current compensation mechanism is greatly constrained by the environment, and ensure the stability of subsequent voltage compensation.

[0097] Specifically, determining the compensation setting node and the compensation method in step S6 includes: S61, taking a setting node whose voltage amplitude is not within the corrected maximum voltage fluctuation range or whose frequency is not within the corrected maximum frequency fluctuation range as a compensation setting node.

[0098] S62: If the voltage amplitude of the compensation setting node is not within the corrected maximum voltage fluctuation range, perform a Class I compensation mark on the compensation setting node.

[0099] S63. If the frequency of the compensation setting node is not within the corrected maximum frequency fluctuation range, perform a Class II compensation mark on the compensation setting node.

[0100] S64. When there is electrical equipment at the compensation setting node, a compensation method is obtained by setting a load compensation setting rule.

[0101] S65. If there is no electrical equipment at the compensation setting node, extract the monitoring temperature value at each monitoring time point from the temperature data, construct a monitoring temperature change curve for each setting node, and use the slope of the monitoring temperature change curve as the temperature change rate.

[0102] S66. If the signs of the temperature change rate and the voltage amplitude change rate are consistent and both are greater than or equal to 0, the reactor group compensation is used as the compensation method. If both are less than 0, the static VAR generator forward compensation is used as the compensation method.

[0103] S67. If the signs of the temperature change rate and the voltage amplitude change rate are inconsistent, when the temperature change rate is greater than or equal to 0 and the voltage amplitude change rate is less than 0, capacitor bank compensation is used as the compensation method; when the temperature change rate is less than 0 and the voltage amplitude change rate is greater than or equal to 0, static VAR generator reverse compensation is used as the compensation method.

[0104] Understandably, the simultaneous increase in temperature and voltage amplitude is most likely due to excess capacitive reactive power in the line. Excess capacitive reactive power will cause the voltage to rise, because the effect of capacitive reactive power in the circuit changes the voltage characteristics of the line. Specifically, capacitive reactive power will increase the electric field energy of the line, thereby driving the voltage up, and the reactor can absorb reactive power. After the reactor group is put into use, it can absorb the capacitive reactive power in the line and reduce the reactive current. As the capacitive reactive power is absorbed, the reactive current in the line decreases, and the voltage will decrease accordingly, thereby alleviating the increase in voltage amplitude. At the same time, due to the reduction in reactive current, according to Joule's law, the line loss will also decrease, which can alleviate the increase in line temperature caused by excessive current.

[0105] Furthermore, the temperature and voltage amplitude drop at the same time, most likely due to excessive inductive reactive power consumption in the line. Inductive reactive power is an important factor in maintaining magnetic field energy in the circuit. When the inductive reactive power consumption is too much, it will lead to insufficient magnetic field energy of the line, which will affect the maintenance of voltage and cause the voltage amplitude to drop. At the same time, the voltage drop will reduce the current in the line. The static VAR generator can output reactive power quickly and continuously, and can accurately adjust the output according to the real-time needs of the system. In this situation where both the temperature and voltage amplitude drop, the reactive power required by the system is supplemented by outputting capacitive reactive power to increase the voltage amplitude.

[0106] Understandably, the voltage amplitude drop is likely due to excessive inductive reactive power consumption in the line. The consumption of inductive reactive power will cause the magnetic field energy of the line to be insufficient, affecting the maintenance of voltage and causing the voltage amplitude to drop. Although the voltage amplitude drops, the temperature rises. This may be because during the voltage drop process, although the current in the line will also decrease due to the voltage reduction, due to certain factors, such as the resistance characteristics of the line itself, other local energy conversions, etc., the line loss is not reduced to a level sufficient to allow the temperature to drop. The capacitor bank can provide capacitive reactive power. After the capacitor bank is put into use, the capacitive reactive power it generates can offset the inductive reactive power, reduce the reactive current, and thus increase the voltage amplitude. When the voltage amplitude increases, the current in the line will increase accordingly when the load resistance is relatively fixed, which may change the thermal effect of the line.

[0107] Furthermore, the increase in voltage amplitude is likely due to excess capacitive reactive power in the line. The static VAR generator can not only output capacitive reactive power to compensate for insufficient inductive reactive power, but also output inductive reactive power to absorb excess capacitive reactive power. In this case where the temperature drops and the voltage amplitude rises, the static VAR generator absorbs excess capacitive reactive power by outputting inductive reactive power, thereby reducing the voltage amplitude.

[0108] Furthermore, the specific settings of the load compensation setting rules in step S64 are as follows: if there is a load at the compensation setting node, the load type is an inductive load and there is no compensation mark, capacitor group compensation is used as the compensation method; if there is a Class I compensation mark, capacitor group compensation and on-load tap-changing transformer compensation are used as compensation methods; if only a Class II compensation mark exists, dynamic voltage restorer compensation is used as the compensation method.

[0109] If there is a load at the compensation setting node, the load type is capacitive load and there is no compensation mark, the reactor group compensation is used as the compensation method. If there is a Class I compensation mark, the reactor group compensation and on-load tap-changing transformer compensation are used as the compensation methods. If only the Class II compensation mark exists, the dynamic voltage restorer compensation is used as the compensation method.

[0110] It should be added that the inductive load mainly faces the problem of voltage drop, and the compensation method focuses on providing capacitive reactive power to increase the voltage, and when necessary, using an on-load voltage regulator to increase the voltage, and using a DVR to deal with sudden voltage drops. While the capacitive load mainly faces the problem of voltage increase, the compensation method focuses on absorbing capacitive reactive power to reduce the voltage, and when necessary, using an on-load voltage regulator to reduce the voltage, and using a DVR to deal with sudden voltage increases. Therefore, the present invention makes targeted compensation settings according to the load type.

[0111] Understandably, a capacitor is an electrical component that can store electric charge. In an AC circuit, a capacitor will generate capacitive reactive power. When there are inductive loads such as motors and transformers in the distribution line that consume a large amount of inductive reactive power and cause the voltage to drop, the capacitor bank is put into use, and the capacitive reactive power generated by it can offset the inductive reactive power, thereby reducing the reactive current in the line, reducing line losses, and then increasing the voltage.

[0112] It is also understandable that the reactor is mainly used to absorb reactive power. When there are capacitive loads such as cable capacitance, a large number of capacitor banks, etc. in the distribution line, which generate too much capacitive reactive power and cause the voltage to rise, the reactor is put into use, which can absorb the capacitive reactive power and reduce the reactive current in the line, thereby reducing the voltage and keeping it within a reasonable range.

[0113] It should be added that when it has been determined that the voltage amplitude is not within the corrected maximum voltage fluctuation range, that is, the Class I compensation mark, and there is an inductive load at the node. On the one hand, the capacitor bank compensation is still to offset the influence of inductive reactive power on the voltage amplitude by providing capacitive reactive power, and try to adjust the voltage amplitude to the normal range. On the other hand, since the voltage amplitude deviation may be large, the addition of on-load tap-changing transformer compensation can achieve a larger voltage adjustment, ensuring that the voltage amplitude can be restored to the appropriate range to meet the voltage requirements of inductive loads and other electrical equipment. When only the Class II compensation mark exists, that is, the main problem is that the frequency is not within the corrected maximum frequency fluctuation range, and there is an inductive load at the node, although the inductive load itself may have a certain impact on the voltage amplitude, the focus at this time is to solve the frequency abnormality problem. The dynamic voltage restorer can maintain the voltage amplitude while adjusting the frequency to prevent the voltage fluctuation that may occur during the frequency adjustment process from affecting the inductive load and other electrical equipment. It can maintain the stability of the voltage amplitude by outputting appropriate compensation voltage according to the voltage and frequency conditions monitored in real time, and at the same time correct the frequency deviation to ensure the normal operation of electrical equipment.

[0114] It is also necessary to add that it has been determined that there is a situation where the voltage amplitude is not within the corrected maximum voltage fluctuation range, that is, the Class I compensation mark, and there is a capacitive load at the node. On the one hand, the compensation of the reactor group is to absorb capacitive reactive power to adjust the voltage amplitude so that it is close to the normal range. On the other hand, since the voltage amplitude deviation may be large, the addition of on-load tap-changing transformer compensation can achieve a larger adjustment, ensuring that the voltage amplitude can be restored to the appropriate range to meet the voltage requirements of capacitive loads and other electrical equipment. When only the Class II compensation mark exists, that is, the main problem is that the frequency is not within the corrected maximum frequency fluctuation range, and there is a capacitive load at the node, although the capacitive load itself may have a certain impact on the voltage amplitude, the focus at this time is to solve the frequency abnormality problem. The dynamic voltage restorer can maintain the voltage amplitude to a certain extent while adjusting the frequency, so as to prevent the voltage fluctuation that may occur during the frequency adjustment process from affecting the capacitive load and other electrical equipment. Therefore, the present invention not only targets the load type, but also combines the compensation mark for flexible compensation settings to ensure the rationality of the compensation settings.

[0115] The embodiment of the present invention effectively solves the problem of the current single compensation mechanism setting by determining the compensation setting nodes and compensation methods, ensures the flexibility of voltage compensation setting, realizes detailed analysis of specific compensation needs and diversified selection of compensation methods, facilitates fast and reliable voltage compensation, and can effectively reduce the impact of voltage fluctuations and deviations, thereby ensuring the safety and reliability of distribution line operation and maintenance.

[0116] The above contents are merely examples and explanations of the concept of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the present invention, they shall all fall within the protection scope of the present invention.

Claims

1. A bidirectional regulation method for distribution line voltage compensation, characterized in that: The method includes: Install high-precision voltage sensors, temperature sensors and bidirectional voltage compensation devices at each node of the distribution line; Building a real-time communication network to connect the sensor, the compensation device and the central controller for communication; Collect voltage data and temperature data of each node in the distribution line in real time, and transmit the collected voltage data and temperature to the central controller through the communication network; Import the past operation monitoring data of the distribution line and analyze the voltage change characteristics based on the real-time collected voltage; According to the voltage change characteristics, determine whether the voltage of the distribution line exceeds the allowable range. If the voltage exceeds the allowable range, proceed to the next step; Determine the compensation setting nodes and compensation methods; The central controller sends a control instruction to the bidirectional voltage compensation device and performs adaptive voltage compensation according to the determined compensation setting node and compensation mode and the voltage data of the compensation setting node collected in real time; The analyzing voltage variation characteristics includes: Extract the monitored voltage value at each monitoring time point from the voltage data, group the monitoring time points into monitoring time windows according to the set monitoring time interval, and calculate the voltage amplitude and frequency of each set node in each monitoring time window; Taking the monitoring time window as the horizontal coordinate and the voltage amplitude as the vertical coordinate, constructing a voltage amplitude change curve of each setting node, and calculating the slope of the voltage amplitude change curve as the voltage amplitude change rate; Construct the frequency change curve of each setting node in the same way as the voltage amplitude change curve, calculate the slope of the frequency change curve as the frequency change rate, and extract the number of fluctuation points of the frequency change curve, and divide it by the number of monitoring time windows, and use the ratio as the frequency fluctuation degree; Extract the voltage amplitude and frequency of each setting node in each monitoring time window on each monitoring day from the past operation monitoring data, and define the voltage change acceptance factor of each setting node; The voltage amplitude change rate, frequency change rate, frequency fluctuation and voltage change acceptance factor of each set node are used as voltage change characteristics; The step of defining the voltage change acceptance factor of each setting node includes: Extract the rated voltage range and the maximum allowable voltage fluctuation range at each setting node from the past operation monitoring data, and integrate them to obtain the reference acceptance voltage range of each setting node; Based on the voltage amplitude in each monitoring time window on each monitoring day, calculating the actual voltage fluctuation range of each set node on each monitoring day; Extract the maximum frequency fluctuation range allowed at each setting node from past operation monitoring data; The actual frequency fluctuation range of each monitoring day is calculated in the same way as the actual voltage fluctuation range, and the deviation monitoring day and the deviation factor of each deviation monitoring day of each set node are determined accordingly; Extracting a set of abnormal events of voltage fluctuation equipment corresponding to each setting node, and extracting the occurrence date and abnormal level of each abnormal event from the abnormal event set; If a deviation monitoring day corresponding to a setting node is consistent with the sending date of a certain abnormal event, the deviation monitoring day is recorded as the target day, and the number of target days is counted; Set the abnormal matching factor of each setting node, denoted as , Indicates setting the node number. ; Compare the target number of each setting node with the number of monitoring days to obtain the abnormal occurrence ratio of each setting node, which is recorded as ; Define the voltage change acceptance factor for each setting node , ; The step of setting the abnormal matching factor of each setting node includes: Based on the reference anomaly level of each pre-set deviation factor, the reference anomaly level of each set node corresponding to each target day is matched; If the reference abnormality level of a set node on a target day is the same as the abnormality level of the corresponding abnormal event of the set node on the target day, the target day is recorded as an abnormal match day, otherwise it is recorded as an abnormal deviation day; If the matching anomaly level of a certain setting node on the abnormal deviation day is higher than the abnormal level of the abnormal event, 0 is used as the abnormal interference factor; If the matching anomaly level of a certain setting node on the abnormal deviation day is lower than the abnormal level of the abnormal event, the number of interval abnormal levels between the matching anomaly level and the abnormal level of the abnormal event is counted and recorded as ,Will As an abnormal interference factor; The average abnormal interference factor of each setting node on each abnormal deviation day is calculated to obtain the average abnormal interference factor of each setting node, which is recorded as ; The number of abnormal matching days of each setting node is counted and compared with the number of target days to obtain the abnormal matching ratio of each setting node, which is recorded as , set the abnormal fit factor of each setting node , , is a natural constant.

2. A bidirectional regulation method for distribution line voltage compensation according to claim 1, characterized in that: The confirmation of each deviation monitoring day of each setting node includes: For each set node, on each monitoring day, the actual voltage fluctuation range of the set node on that day is overlapped and compared with the reference acceptance voltage range of the node, and the ratio of the overlap range length to the actual voltage fluctuation range length is calculated as the voltage amplitude change consistency; For each setting node and each monitoring day, the actual frequency fluctuation range of the setting node on each monitoring day is overlapped and compared with the maximum frequency fluctuation range allowed by the electrical equipment at the setting node, and the frequency change consistency is calculated in the same way as the voltage amplitude change consistency; The existence of voltage amplitude change consistency or frequency change consistency less than the set reference change consistency is used as a fluctuation deviation certification condition; If a setting node meets the fluctuation deviation authentication condition on a certain monitoring day, the monitoring day is recorded as the deviation monitoring day, so as to obtain the deviation monitoring days of each setting node.

3. A bidirectional regulation method for distribution line voltage compensation as claimed in claim 2, characterized in that: The specific confirmation process of the deviation factor of each deviation monitoring day includes: If the voltage amplitude change consistency is less than the set reference change consistency on a certain deviation monitoring day, As the deviation factor for the deviation monitoring day; If the frequency change consistency is less than the set reference change consistency on a certain deviation monitoring day, As the deviation factor for the deviation monitoring day; If the voltage amplitude change consistency and frequency change consistency of a certain deviation monitoring day are both less than the set reference change consistency, The deviation factor of the deviation monitoring day is used as the deviation factor of the deviation monitoring day, thereby obtaining the deviation factor of each deviation monitoring day.

4. A bidirectional regulation method for distribution line voltage compensation according to claim 1, characterized in that: The determining whether the voltage of the power distribution line exceeds the allowable range includes: Based on the voltage variation characteristics, the voltage excess redundancy compensation factor of each setting node is calculated, and the maximum frequency fluctuation range and the maximum voltage fluctuation range allowed by the electrical equipment at each setting node are corrected accordingly to obtain the corrected maximum frequency fluctuation range and the maximum voltage fluctuation range; For each setting node, in each monitoring time window, check whether its voltage amplitude and frequency are both within the corrected maximum voltage fluctuation range and maximum frequency fluctuation range; If the voltage amplitude and frequency of each setting node in each monitoring time window are within the corrected maximum voltage fluctuation range and maximum frequency fluctuation range, it is judged that the voltage of the distribution line does not exceed the allowable range; otherwise, it is judged that the voltage of the distribution line exceeds the allowable range.

5. A bidirectional regulation method for distribution line voltage compensation as claimed in claim 4, characterized in that: The calculating of the voltage exceeding redundancy compensation factor of each setting node includes: The voltage amplitude change rate, frequency change rate and frequency fluctuation of each setting node are recorded as , and ; Calculate the voltage excess redundancy compensation factor for each setting node , , and They are the reference change rate, frequency fluctuation and voltage change acceptance factor.

6. A bidirectional regulation method for distribution line voltage compensation according to claim 4, characterized in that: The determining of the compensation setting node and the compensation method includes: The setting node whose voltage amplitude is not within the corrected maximum voltage fluctuation range or whose frequency is not within the corrected maximum frequency fluctuation range is used as a compensation setting node; If the voltage amplitude of the compensation setting node is not within the corrected maximum voltage fluctuation range, the compensation setting node is marked as Class I compensation; If the frequency of the compensation setting node is not within the corrected maximum frequency fluctuation range, the compensation setting node is marked as type II compensation; When there is electrical equipment at the compensation setting node, the compensation method is obtained by setting the load compensation setting rule; If there is no electrical equipment at the compensation setting node, extract the monitoring temperature value at each monitoring time point from the temperature data, construct a monitoring temperature change curve for each setting node, and use the slope of the monitoring temperature change curve as the temperature change rate; If the signs of the temperature change rate and the voltage amplitude change rate are consistent and both are greater than or equal to 0, the reactor group compensation is used as the compensation method. If both are less than 0, the static VAR generator forward compensation is used as the compensation method. If the signs of the temperature change rate and the voltage amplitude change rate are inconsistent, when the temperature change rate is greater than or equal to 0 and the voltage amplitude change rate is less than 0, capacitor bank compensation is used as the compensation method; when the temperature change rate is less than 0 and the voltage amplitude change rate is greater than or equal to 0, static VAR generator reverse compensation is used as the compensation method.

7. A bidirectional regulation method for distribution line voltage compensation according to claim 6, characterized in that: The specific settings of the load compensation setting rules are as follows: If there is a load at the compensation setting node, the load type is an inductive load and there is no compensation mark, capacitor bank compensation is used as the compensation method. If there is a Class I compensation mark, capacitor bank compensation and on-load tap-changing transformer compensation are used as the compensation methods. If there is only a Class II compensation mark, dynamic voltage restorer compensation is used as the compensation method. If there is a load at the compensation setting node, the load type is capacitive load and there is no compensation mark, the reactor group compensation is used as the compensation method. If there is a Class I compensation mark, the reactor group compensation and on-load tap-changing transformer compensation are used as the compensation methods. If only the Class II compensation mark exists, the dynamic voltage restorer compensation is used as the compensation method.

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