Circuit breaker phase selection closing real-time control method and related device

Abstract

The invention belongs to the technical field of circuit breakers, and relates to a circuit breaker phase selection closing real-time control method and a related device. The control method comprises the following steps: calculating the actual insulation strength drop rate of on-load phase-selection closing of the circuit breaker according to basic parameters; judging whether the actual insulation strength reduction rate of the on-load phase-selection closing of the circuit breaker meets the operation requirement of phase-selection closing or not, and if not, giving an alarm; if yes, judging whether the mechanical dispersibility of the circuit breaker meets the distribution range of the standard deviation of the closing time or not; if the distribution range of the standard deviation is met, an electrical closing target point of the phase selection device is adjusted; if the distribution range of the standard deviation is not met, judging whether the mechanical dispersibility of the circuit breaker meets a phase selection closing limit requirement range or not; if the phase selection switch-on limit requirement range is not met, an alarm is given; and if the phase selection switch-on limit requirement range is met, adjusting the electrical switch-on target point of the phase selection device. The problems that parameter setting of the phase selection closing device is solidified, and parameter self-adaptive adjustment cannot be achieved are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of circuit breakers, and particularly relates to a real-time control method for phase-selective closing of a circuit breaker and related devices. Background Art

[0002] An AC filter circuit breaker is one of the key devices in the AC filter yard of a converter station in a UHV DC transmission system. Its uses are as follows: by opening and closing the AC filter circuit breaker, the AC filter bank (or capacitor) is put into and taken out of operation, so as to realize reactive power compensation on the AC side of the system, filter out harmonics, and can adjust the AC bus voltage to ensure power quality.

[0003] Under normal circumstances, the capacity of a single-phase AC filter in a DC system converter station is relatively large. If the switching moment of the filter is not selected properly, large inrush current shocks and overvoltages will be generated. To reduce the impact of the inrush current generated when the AC filter circuit breaker is put into the AC filter (during closing) on the AC system, generally, a phase-selective closing device is configured for the AC filter circuit breaker to realize the control of the closing phase of the circuit breaker, ensure that the circuit breaker is put into operation near the voltage zero crossing point, and effectively reduce the impact of the closing inrush current.

[0004] Commutation failure is one of the faults with a relatively high occurrence probability in a DC transmission system. The main reason is that the AC system fault causes the AC bus voltage on the inverter side to drop. And the phase-selective closing deviation of the AC filter circuit breaker is too large, which makes the closing inrush current increase, causes the distortion of the AC bus voltage waveform, advances the natural commutation point, results in a smaller extinction angle γ, and causes commutation failure. Commutation failure will lead to adverse consequences such as a reduction in DC transmission power, a decrease in voltage, an increase in current, and a shortening of the service life of the converter valve, and even cause the DC outage.

[0005] In a DC system, generally, a commutation failure prediction control method is adopted to prevent commutation failure caused by AC faults. Its action mechanism is as follows: the DC control system detects the distortion of the AC bus voltage, triggers the action of the commutation failure prediction control function, and makes the inverter trigger in advance, that is, increases the extinction angle γ, to prevent the commutation failure caused by the drop of the extinction angle γ due to AC disturbances.

[0006] However, due to different phase-selective closing deviations of the AC filter circuit breaker, the closing inrush currents are also different, and the distortion degrees of the AC bus voltage waveforms caused are different. Even if the commutation failure prediction control function is triggered to act, the greater the increment of the extinction angle γ, the greater the DC voltage drop value, and the greater the AC bus voltage drop will be. When it exceeds a certain threshold, commutation failure still cannot be avoided. Therefore, reasonably adjusting the parameters of the phase-selective closing device to make its phase-selective closing deviation as small as possible can effectively avoid commutation failure.

[0007] The main factors affecting the accuracy of phase selection control are: the mechanical dispersion of the circuit breaker; the rate of decrease of dielectric strength (RDDS). Due to the mechanical characteristics of the AC filter circuit breaker in the converter station itself, the rate of decrease of the dielectric strength of the insulating medium will gradually change over time. The parameters of the existing phase selection closing device are not adjusted after being set and accepted. After the equipment has been in operation for a period of time, the parameters of the phase selection closing device are generally manually adjusted only based on the mechanical characteristics during the maintenance period. There are lags and insufficient accuracy control in the parameter setting of the phase selection closing device, resulting in phase selection closing deviation and even commutation failure of the DC transmission system. Summary of the Invention

[0008] The purpose of the present invention is to provide a real-time control method and related device for phase selection closing of a circuit breaker, which solves the problem that the parameter setting of the phase selection closing device is fixed and the parameter adaptive adjustment cannot be realized.

[0009] The present invention is realized through the following technical solutions: The present invention discloses a real-time control method for phase selection closing of a circuit breaker, including the following steps: S1. Obtain basic parameters, where the basic parameters include the actual electrical closing phase of the circuit breaker for phase selection closing, the closing time of the auxiliary contact when carrying load, the closing time of the main contact, and the closing time of the auxiliary contact; S2. Calculate the actual rate of decrease of dielectric strength of the circuit breaker for phase selection closing when carrying load according to the basic parameters; S3. Judge whether the actual rate of decrease of dielectric strength of the circuit breaker for phase selection closing when carrying load meets the operation requirements of phase selection closing. If it does not meet the operation requirements of phase selection closing, give an alarm and end the process; If it meets the operation requirements of phase selection closing, start S4; S4. Judge whether the mechanical dispersion of the circuit breaker meets the distribution range of the standard deviation of the closing time; if it meets the distribution range of the standard deviation, adjust the electrical closing target point of the phase selection device; If it does not meet the distribution range of the standard deviation, start S5; S5. Judge whether the mechanical dispersion of the circuit breaker meets the limit requirement range of phase selection closing; If it does not meet the limit requirement range of phase selection closing, give an alarm and end the process; If it meets the limit requirement range of phase selection closing, then adjust the electrical closing target point of the phase selection device.

[0010] Further, in S1, the actual electrical closing phase α of the circuit breaker for phase selection closing is determined from the oscillogram of the circuit breaker for phase selection closing operation when carrying load; From the time when the phase selection device issues a phase selection closing command to the time when the auxiliary contact feedbacks a closing signal, the closing time T of the auxiliary contact when carrying load is obtainedECaux ; The main contact closing time and the auxiliary contact closing time are obtained through multiple closing characteristic tests of the circuit breaker under no-load conditions.

[0011] Furthermore, calculate the actual insulation strength degradation rate of the circuit breaker with load and phase-selection closing, specifically: First, calculate the closing time difference between the main contact and the auxiliary contact. The calculation formula is: △ Caux =T Caux -T Cmain ; Wherein, T Cmain is the main contact closing time, T Caux is the auxiliary contact closing time, and △ Caux is the closing time difference between the main contact and the auxiliary contact; Based on the closing time T ECaux of the auxiliary contact with load, and the closing time difference △ Caux between the main contact and the auxiliary contact, calculate the closing time T ECmain of the main contact of the circuit breaker with load. The formula is: T ECmain =T ECaux -△ Caux ; According to the actual electrical closing phase of the circuit breaker with phase-selection closing and the closing time T ECmain of the main contact of the circuit breaker with load, calculate the actual insulation strength degradation rate of the circuit breaker with phase-selection closing and load. The formula is: ; ; Wherein, U P is the peak value of the voltage to ground; T pre is the pre-breakdown time; is the angular frequency corresponding to the power frequency; T is the power frequency period; N represents the largest integer multiple of 1 / 2 power frequency period.

[0012] Furthermore, determine whether the actual insulation strength degradation rate of the circuit breaker with phase-selection closing and load meets the operation requirements of phase-selection closing, specifically: Take the average value RDDS ave of the actual insulation strength degradation rates of multiple circuit breakers with phase-selection closing and load; Judge whether the average value RDDS ave of the insulation degradation rate is less than the critical value RDDS CD of the insulation degradation rate. If RDDS ave <RDDS CD, it is determined that the insulation strength degradation rate does not meet the requirements for synchro-switching operation; if RDDS ave ≥RDDS CD , it is determined that the insulation strength degradation rate meets the requirements for synchro-switching operation.

[0013] Furthermore, S4 is specifically as follows: Obtain the sample standard deviation of mechanical dispersion based on the main contact closing time ; Judge whether the sample standard deviation of mechanical dispersion is within the distribution range of the standard deviation of the closing time. If it is within the distribution range of the standard deviation of the closing time, the mechanical dispersion of the circuit breaker meets the engineering requirements, and the electrical closing target point of the phase selection device is adjusted; if it is not within the distribution range of the standard deviation of the closing time, the mechanical dispersion of the circuit breaker does not meet the engineering requirements; The distribution range of the standard deviation of the closing time is -1 1.

[0014] Furthermore, S5 is specifically as follows: Judge whether the sample standard deviation of mechanical dispersion meets the synchro-switching limit requirement range; The synchro-switching limit requirement range is ; wherein, is the angle at which the synchro-switching of the circuit breaker deviates from the zero crossing of the voltage when triggering the commutation failure prediction alarm of the DC system; is the angular frequency corresponding to the power frequency; When or , it is determined that the mechanical dispersion of the circuit breaker does not meet the synchro-switching limit requirement range, and the commutation failure prediction alarm requirement is triggered; The sample standard deviation of mechanical dispersion meets the synchro-switching limit requirement range, then the mechanical dispersion of the circuit breaker meets the requirement of not triggering the commutation failure prediction alarm, and the electrical closing target point of the phase selection device is adjusted.

[0015] Furthermore, the calculation expression for adjusting the electrical closing target point of the phase selection device is: ; wherein, is the closing phase correction coefficient, ; sin() represents the sine function; The value of is adjusted in real time according to statistical data, and the confidence interval of the value of is within the range of

[0016] The present invention also discloses a real-time control system for phase-selective closing of a circuit breaker, including: A data acquisition module, configured to acquire basic parameters, where the basic parameters include the actual electrical closing phase of the circuit breaker for phase-selective closing, the closing time of the auxiliary contact when under load, the closing time of the main contact, and the closing time of the auxiliary contact; An insulation strength degradation rate calculation module, configured to calculate the actual insulation strength degradation rate of the circuit breaker for phase-selective closing under load according to the basic parameters; A first judgment module, configured to judge whether the actual insulation strength degradation rate of the circuit breaker for phase-selective closing under load meets the requirements for phase-selective closing operation. If it does not meet the requirements for phase-selective closing operation, an alarm is given and the process ends; If it meets the requirements for phase-selective closing operation, a second judgment module is started; A second judgment module, configured to judge whether the mechanical dispersion of the circuit breaker meets the distribution range of the standard deviation of the closing time; if it meets the distribution range of the standard deviation, an adjustment module is started; If it does not meet the distribution range of the standard deviation, a third judgment module is started; A third judgment module, configured to judge whether the mechanical dispersion of the circuit breaker meets the range of the limit requirements for phase-selective closing; If it does not meet the range of the limit requirements for phase-selective closing, an alarm is given and the process ends; If it meets the range of the limit requirements for phase-selective closing, the adjustment module is started; An adjustment module, configured to adjust the electrical closing target point of the phase-selection device.

[0017] The present invention also discloses a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the real-time control method for phase-selective closing of the circuit breaker is implemented.

[0018] The present invention also discloses a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the real-time control method for phase-selective closing of the circuit breaker is implemented.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention discloses a real-time control method for phase-selective closing of a circuit breaker. First, accurately calculate the actual insulation strength degradation rate of the circuit breaker with load during phase-selective closing based on basic parameters. When the requirements for phase-selective closing operation are met, statistically analyze the range of mechanical dispersion changes of the circuit breaker, and determine whether the mechanical dispersion changes of the circuit breaker meet the distribution range of the standard deviation. If it meets the distribution range of the standard deviation, the electrical closing target point of the phase-selection device can be directly adjusted; if it does not meet the distribution range of the standard deviation, further determine whether the mechanical dispersion of the circuit breaker meets the limit requirements for phase-selective closing; if the mechanical dispersion of the circuit breaker does not meet the limit requirements for phase-selective closing, an alarm is issued; if it meets the limit requirements for phase-selective closing, the electrical closing target point of the phase-selection device can be adjusted to ensure that the mechanical dispersion of the circuit breaker deviates from the engineering requirement value without triggering a commutation failure prediction alarm. The electrical closing target point of the phase-selection device is adjusted in real time according to the actual insulation strength degradation rate of phase-selective closing and the mechanical dispersion of the circuit breaker. The method of the present invention is simple, reliable, and highly practical, effectively improving the control accuracy of phase-selective closing, eliminating the limitation of determining the optimal closing phase by human factors, and effectively suppressing the commutation failure fault caused by the distortion of the AC voltage waveform due to the deviation of phase-selective closing.

[0020] Furthermore, during the process of determining whether the actual insulation strength degradation rate of the circuit breaker with load during phase-selective closing meets the requirements for phase-selective closing operation, a critical value of the insulation strength degradation rate is introduced, and the average value of the actual insulation degradation rate of the circuit breaker is compared with the critical value of the insulation strength degradation rate in real time to determine whether the actual insulation degradation rate of the circuit breaker meets the requirements for phase-selective closing, so as to realize the state evaluation of the actual insulation degradation rate of the circuit breaker during operation.

[0021] Furthermore, the present invention determines the limit requirements for phase-selective closing according to the phase-selection closing phase deviation angle when triggering the commutation failure prediction alarm, controls the set value of the closing phase of the phase-selection closing device within the limit value range of mechanical dispersion, and determines whether the sample standard deviation of mechanical dispersion meets the limit requirements for phase-selective closing. If it does, the phase-selection closing deviation can be effectively controlled so as not to trigger the commutation failure prediction alarm. If not, it is determined that the mechanical dispersion of the circuit breaker does not meet the limit requirements for phase-selective closing, and the commutation failure prediction alarm requirement is triggered.

[0022] Furthermore, the present invention obtains the actual insulation strength degradation rate of the circuit breaker with load during phase-selective closing according to the actual closing phase and mechanical closing time of the circuit breaker during phase-selective closing. According to the change of the insulation strength degradation rate and the mechanical closing dispersion, a closing phase correction coefficient is introduced to realize the real-time adjustment of the set value of the closing phase of the phase-selection device, so as to achieve the precise control of phase-selective closing and reduce the phase-selective closing deviation. Description of the Drawings

[0023] Figure 1 is a flowchart of a real-time control method for phase-selective closing of a circuit breaker according to the present invention; Figure 2 This is the schematic diagram of a real-time control system for phase-selective closing of a circuit breaker according to the present invention; Figure 3 To meet the slope requirement of the insulation degradation rate for phase-selective closing conditions; Figure 4 The dispersion of the electrical closing target point caused by the dispersion of the insulation degradation rate; Figure 5 The dispersion of the electrical closing target point caused by mechanical dispersion; Figure 6 To determine the range of phase-selective closing limit requirements according to the phase-selective closing angle for predicting and warning of commutation failure triggering. Specific embodiments

[0024] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further detailed description is provided in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments.

[0025] The detailed description of the embodiments of the present invention provided in the following drawings is not intended to limit the scope of the present invention to be protected, but only represents a selected embodiment of the present invention. Based on the drawings and embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present invention.

[0026] Explanation of related technical terms: AC filter circuit breaker: In a high-voltage DC transmission system, under specified operating conditions, a circuit breaker that can carry and frequently close and open the rated current of the AC filter circuit and the reactive power compensation capacitor circuit, close the inrush current of the back-to-back capacitor bank, and has the ability to close and break the rated short-circuit current.

[0027] Phase-selective closing: During the closing process of a circuit breaker, there are certain specific phases such that if the circuit breaker exactly completes the electrical closing at this moment, the closing transient process can achieve a relatively smooth transition, reducing the transient inrush current or overvoltage impact to improve system stability.

[0028] Commutation failure: In a converter, if the valve that exits conduction fails to recover its blocking ability within a certain period under the action of the reverse voltage, or the commutation process is not completed during the reverse voltage period, then when the valve voltage becomes positive, the valves to be commutated will all reverse commutate to the valve that was originally scheduled to exit conduction. This situation is called commutation failure.

[0029] Closing inrush current: In a power system, when a capacitor is put into operation, a closing inrush current is generated instantaneously at the moment of closing and putting into operation.

[0030] The features and performance of the present invention will be further described in detail below in conjunction with embodiments.

[0031] Embodiment 1 As Figure 1 shown, the present invention discloses a real-time control method for selected-phase closing, including the following steps: S1. Obtain basic parameters, where the basic parameters include the actual electrical closing phase of the circuit breaker for selected-phase closing, the closing time of the auxiliary contact when under load, the closing time of the main contact, and the closing time of the auxiliary contact; S2. Calculate the actual insulation strength degradation rate of the circuit breaker for selected-phase closing under load according to the basic parameters; S3. Determine whether the actual insulation strength degradation rate of the circuit breaker for selected-phase closing under load meets the requirements for selected-phase closing operation. If it does not meet the requirements for selected-phase closing operation, give an alarm and end the process; If it meets the requirements for selected-phase closing operation, start S4; S4. Determine whether the mechanical dispersion of the circuit breaker meets the distribution range of the standard deviation of the closing time; if it meets the distribution range of the standard deviation, adjust the electrical closing target point of the phase selection device; If it does not meet the distribution range of the standard deviation, start S5; S5. Determine whether the mechanical dispersion of the circuit breaker meets the range of requirements for the limit of selected-phase closing; If it does not meet the range of requirements for the limit of selected-phase closing, give an alarm and end the process; If it meets the range of requirements for the limit of selected-phase closing, it means that the mechanical dispersion of the circuit breaker meets the requirement of not triggering the commutation failure prediction alarm, and adjust the electrical closing target point of the phase selection device.

[0032] Based on the measured data of selected-phase closing, the present invention accurately calculates the actual insulation strength degradation rate of the circuit breaker for selected-phase closing under load, and statistically analyzes the change range of the mechanical dispersion of the circuit breaker in real time. Then, logical judgments are made based on the changes of the two, and finally, it is successively determined whether the actual insulation strength degradation rate of the circuit breaker for selected-phase closing under load meets the requirements for selected-phase closing operation, whether the mechanical dispersion of the circuit breaker meets the distribution range of the standard deviation of the closing time, and whether the mechanical dispersion of the circuit breaker meets the deviation requirement of the commutation failure prediction alarm.

[0033] Relationship between the phase selection device and the circuit breaker: The selected-phase closing and opening technology is also called phase control technology. The phase selection device controls the closing and opening of the circuit breaker, enabling the circuit breaker to close or open at a predetermined voltage or current phase, realizing a smooth transition of the transient process of closing and opening, thereby reducing the impact of transient inrush current or overvoltage on equipment and systems and improving system stability.

[0034] Embodiment 2 On the basis of Embodiment 1, in S1, the circuit breaker conducts multiple closing characteristic tests under no-load conditions to obtain the main contact closing time T Cmain and the auxiliary contact closing time T Caux .

[0035] In the multiple closing characteristic tests, select the starting position, ending position, and intermediate position of the auxiliary switch to test their respective closing times, and select the auxiliary contact with a relatively stable closing time difference between the main contact and the auxiliary contact as the closing-assist auxiliary contact for phase selection closing.

[0036] The auxiliary switch is usually linked with the main contact of the circuit breaker and is used to reflect the opening and closing states of the circuit breaker. The starting position generally refers to the initial state of the auxiliary switch before the closing operation of the circuit breaker; the ending position is the final state of the auxiliary switch after the closing operation is completed; the intermediate position is a certain intermediate transition state passed by the auxiliary switch during the closing process. Measuring the closing times at these three positions can more carefully understand the operation of the auxiliary switch during the entire closing process, and then analyze whether the closing characteristics of the circuit breaker meet the requirements.

[0037] Determine the actual electrical closing phase of the circuit breaker for phase selection closing from the oscillogram of the circuit breaker's load-bearing phase selection closing operation .

[0038] From the time when the phase selection device issues the phase selection closing command to the time when the closing-assist auxiliary contact of the auxiliary contact feedbacks the closing signal, obtain the closing time T ECaux of the auxiliary contact of the auxiliary contact under load.

[0039] Embodiment 3 On the basis of Embodiment 2, S2 is specifically as follows: First, calculate the closing time difference △ Caux between the main contact and the auxiliary contact, and the expression is: △ Caux =T Caux -T Cmain ; Based on the closing time T ECaux of the auxiliary contact of the auxiliary contact under load and the closing time difference △ Caux between the main contact and the auxiliary contact obtained in step 1, calculate the closing time T ECmain of the main contact of the circuit breaker under load, and the expression is: T ECmain =T ECaux -△ Caux .

[0040] According to the actual electrical closing phase of the circuit breaker for phase selection closing and the closing time T ECmain of the main contact of the circuit breaker under load, calculate the actual insulation strength degradation rate of the circuit breaker for phase selection closing under load, and the expression is: ; ; wherein, U P is the peak value of the relative ground voltage, with the unit of kV; T pre is the pre-breakdown time, with the unit of ms; is the angular frequency corresponding to the power frequency, with the unit of rad / ms; is the largest integer multiple of 1 / 2 power frequency period, T is the power frequency period; the actual electrical closing phase α of the breaker's phase-selection closing is adjusted in real time according to the measured value; is the pre-breakdown time.

[0041] Record the actual insulation strength degradation rate RDDS of each breaker's on-load phase-selection closing real , compare the current insulation strength degradation rate RDDS real this time with the previous insulation strength degradation rate RDDS real last time , and select the insulation strength degradation rate with a smaller value (smaller slope) as the reference parameter for setting the electrical closing target phase of the phase-selection device.

[0042] Specifically, S3 is as follows: Take the actual insulation strength degradation rate RDDS of the breaker's on-load phase-selection closing in the recent 5 times real , and calculate its average value RDDS ave . If RDDS ave < RDDS CD , it is determined that the insulation strength degradation rate of the breaker does not meet the operation requirements of the breaker's phase-selection closing, and the control system sends an alarm signal or message to the control and protection.

[0043] wherein, RDDS CD is the critical value of the insulation degradation rate, RDDS CD .

[0044] If RDDS ave ≥ RDDS CD , it is determined that the insulation strength degradation rate meets the operation requirements of the phase-selection closing.

[0045] The method of the present invention introduces the critical value RDDS of the insulation strength degradation rate CD , and evaluates the actual insulation strength degradation rate of the breaker. By selecting the actual insulation strength degradation rate RDDS of the breaker's on-load phase-selection closing in 5 times real to calculate its average value, and comparing the average value RDDS of the insulation strength degradation rate ave with the critical value RDDS of the insulation strength degradation rate CD , a judgment is given. When RDDS ave < RDDS CDWhen the circuit breaker RDDS does not meet the operating requirements, the system alarms and exits operation; when RDDS ave ≥RDDS CD When, according to the change of the circuit breaker RDDS, check and adjust the closing phase setting value of the phase selection device. The specific reasoning is as follows: The slope of the circuit breaker RDDS must be greater than the critical point slope (the derivative at the voltage zero crossing with a peak value of U P , and the actual optimal closing moment will lag behind the theoretical reference voltage zero crossing. As Figure 1 shown in RDDS1, it intersects with the reference voltage at point B, and the arc starts to be generated. TD2 is the time interval from the voltage zero crossing to the arc starting, and TD3 is the pre-arcing time, that is, the time interval from the arc starting at the contact gap to the final contact of the switch contacts. The actual closing moment is Tc. In this case, the voltage at which the switch starts to arc is not high, and the inrush current is small. And because the values of TD2 and TD3 are very small, even if there is a certain deviation in RDDS1, the change in the closing moment is not large, ensuring good stability.

[0046] If the slope of the circuit breaker RDDS is less than the critical point slope, affected by mechanical dispersion, as Figure 3 shown in RDDS2 in, the RDDS curve may intersect with the reference voltage at point A before the voltage zero crossing and the arc starts to be generated. Since the voltage at this point is close to the peak value, the inrush current is large, and it is extremely easy to cause the distortion of the AC voltage waveform and lead to the commutation failure of the DC system. Therefore, the slope of the circuit breaker RDDS must be greater than the critical slope.

[0047] Embodiment 4 On the basis of Embodiment 3, S4 is specifically: Record and statistically calculate the closing time T Cmain of the main contact, and use the conventional calculation method of mathematical statistics to obtain the average value of the mechanical closing time and the sample standard deviation of the mechanical dispersion , and adjust the closing voltage phase of the phase selection device according to the distribution range of the standard deviation of the closing time.

[0048] The distribution range of the standard deviation of the closing time is -1 1. If within this distribution range, the mechanical dispersion of the circuit breaker meets the engineering requirements, directly adjust the electrical closing target point of the phase selection device; if >1 or <-1, the mechanical dispersion of the circuit breaker does not meet the engineering requirements.

[0049] Embodiment 5 On the basis of Embodiment 4, S5 is specifically: When the mechanical dispersion of the circuit breaker does not meet the engineering requirements, in order to avoid the prediction alarm of the commutation failure of the DC system triggered by the AC voltage distortion caused by the phase selection closing deviation of the circuit breaker, it is necessary to make , that is, the mechanical dispersion of the circuit breaker under the condition of not triggering the commutation failure prediction alarm of the DC system should meet the limit requirements of the phase selection closing: ; Among them, is the angle at which the phase selection closing of the circuit breaker deviates from the zero crossing of the voltage when triggering the commutation failure prediction alarm of the DC system.

[0050] When the mechanical dispersion of the circuit breaker or , it is determined that the mechanical dispersion does not meet the operation requirements of the circuit breaker phase selection closing. The control system sends an alarm signal or message to the control and protection, and triggers the commutation failure prediction alarm of the DC system.

[0051] According to the closing time T ECmain of the main break contact of the circuit breaker under load, the sample standard deviation σ of the mechanical dispersion, and the phase deviation of the phase selection closing without triggering the commutation failure prediction alarm, it can be obtained that: The time T shift when the mechanical closing target point of the phase selection device deviates from the zero voltage point is: T shift =β ; When the mechanical dispersion of the circuit breaker meets the requirement of not triggering the commutation failure prediction alarm, that is , calculate the electrical closing target point of the phase selection device, and the calculation expression is: ; Among them, is the closing phase correction coefficient, ; sin() represents the sine function; The value of is adjusted in real time according to statistical data, but the confidence interval of the value of cannot exceed the range; The adjustment of the electrical closing target point of the phase selection device is determined by the corresponding to the smaller value of the insulation strength degradation rate slope determined in Embodiment 3, the actual electrical closing phase

[0052] of the circuit breaker phase selection closing, and the sample standard deviation of the mechanical dispersion for multiple consecutive times, and is continuously corrected according to its change. ECmain, obtain the actual insulation strength degradation rate of the circuit breaker; according to the changes in the insulation strength degradation rate and the mechanical closing dispersion, introduce a closing phase correction coefficient to adjust the set value of the closing phase of the phase selection device in real time, achieve precise control of the phase selection closing, and reduce the deviation of the phase selection closing. The specific reasoning is as follows: The statistical characteristics of dielectric breakdown have an important impact on the insulation strength degradation rate. The actual insulation strength degradation rate will show a certain dispersion. As Figure 4 shown, the electrical closing target points of the phase selection device under different insulation strength degradation rates are also different. Adjusting the electrical closing target point of the phase selection device in real time according to the change of the circuit breaker's RDDS helps to achieve precise control of the phase selection closing.

[0053] During the long-term operation of the circuit breaker, the mechanical dispersion is inevitably affected by the control voltage, ambient temperature, mechanism oil pressure, air pressure, and action intermittent time and will change. As Figure 5 shown, the electrical closing target points of the phase selection device with different mechanical dispersions are also different. Adjusting the electrical closing target point of the phase selection device in real time according to the change of the circuit breaker's mechanical dispersion helps to achieve precise control of the phase selection closing.

[0054] The present invention determines the limit requirement range of the phase selection closing according to the phase selection closing phase deviation angle when triggering the commutation failure prediction alarm, controls the set value of the closing phase of the phase selection closing device within the limit requirement range of the phase selection closing, effectively controls the phase selection closing deviation, and prevents it from triggering the commutation failure prediction alarm.

[0055] Statistically analyze the range of the phase selection closing phase deviation angle when triggering the commutation failure prediction alarm. Use the minimum value of the deviation angle as the limit value for controlling the mechanical dispersion range. As Figure 6 shown, when or , the mechanical dispersion of the circuit breaker is extremely likely to trigger the commutation failure prediction alarm, does not meet the operation requirements, the system alarms and exits the operation; when , adjust the closing target point of the phase selection device according to the change of the circuit breaker's mechanical dispersion.

[0056] In summary, the present invention determines the actual closing time of the circuit breaker through the closing time difference △ caux between the main contact and the auxiliary contact of the circuit breaker and the actual electrical closing phase measured by the phase selection device, accurately calculates the actual insulation strength degradation rate of the circuit breaker with load phase selection closing. And according to the change of the mechanical dispersion, introduce a closing phase correction coefficient, and realize the real-time correction of the electrical closing target point of the phase selection device by adjusting the correction coefficient. At the same time, make a logical judgment on the actual insulation strength degradation rate of the circuit breaker with load phase selection closing and the real-time statistical change of the circuit breaker's mechanical dispersion, providing an operation and maintenance basis for the phase selection closing of the AC filter circuit breaker in the converter station.

[0057] As Figure 2As shown, the present invention also discloses a real-time control system for breaker phase-selective closing, including: A data acquisition module, configured to acquire basic parameters, where the basic parameters include the actual electrical closing phase of the breaker phase-selective closing, the closing time of the auxiliary contact when under load, the closing time of the main contact, and the closing time of the auxiliary contact; An insulation strength degradation rate calculation module, configured to calculate the actual insulation strength degradation rate of the breaker phase-selective closing under load according to the basic parameters; A first judgment module, configured to judge whether the actual insulation strength degradation rate of the breaker phase-selective closing under load meets the requirements for phase-selective closing operation. If it does not meet the requirements for phase-selective closing operation, an alarm is given and the process ends; If it meets the requirements for phase-selective closing operation, a second judgment module is started; A second judgment module, configured to judge whether the mechanical dispersion of the breaker meets the distribution range of the standard deviation of the closing time; if it meets the distribution range of the standard deviation, an adjustment module is started; If it does not meet the distribution range of the standard deviation, a third judgment module is started; A third judgment module, configured to judge whether the mechanical dispersion of the breaker meets the range of requirements for the phase-selective closing limit; If it does not meet the range of requirements for the phase-selective closing limit, an alarm is given and the process ends; If it meets the range of requirements for the phase-selective closing limit, then the mechanical dispersion of the breaker meets the requirement of not triggering the commutation failure prediction alarm, and the adjustment module is started; An adjustment module, configured to adjust the electrical closing target point of the phase selection device.

[0058] The present invention also discloses a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the real-time control method for breaker phase-selective closing is implemented. Among them, the memory may include a memory, such as a high-speed random access memory, and may also include a non-volatile memory, such as at least one magnetic disk memory, etc.; the processor, network interface, and memory are interconnected through an internal bus, and this internal bus can be an Industry Standard Architecture bus, a Peripheral Component Interconnect standard bus, an Extended Industry Standard Architecture bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. The memory is used to store programs. Specifically, the program may include program code, and the program code includes computer operation instructions. The memory may include a memory and a non-volatile memory, and provides instructions and data to the processor.

[0059] The present invention also discloses a computer-readable storage medium storing a computer program, which when executed by a processor implements the real-time control method for breaker phase-selection closing. Specifically, the computer-readable storage medium includes, but is not limited to, volatile memory and / or non-volatile memory. The volatile memory may include random access memory and / or cache memory, etc. The non-volatile memory may include read-only memory, hard disk, flash memory, optical disc, magnetic disk, etc.

[0060] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, optical storage, etc.) containing computer-usable program code.

[0061] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for realizing the functions specified in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0062] These computer program instructions can also be stored in a computer-readable memory capable of guiding a computer or other programmable data processing devices to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means realizes the functions specified in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0063] These computer program instructions can also be loaded onto a computer or other programmable data processing devices, so that a series of operation steps are executed on the computer or other programmable devices to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable devices provide steps for realizing the functions specified in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0064] Finally, 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 it. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: it is still possible to modify the specific implementation manners of the present invention or make equivalent replacements, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the present invention.

Claims

1. A real-time control method for phase-selection closing of a circuit breaker, characterized in that, It includes the following steps: S1. Obtain basic parameters, where the basic parameters include the actual electrical closing phase of the circuit breaker's phase-selection closing, the closing time of the auxiliary contact when under load, the closing time of the main contact, and the closing time of the auxiliary contact; S2. Calculate the actual insulation strength degradation rate of the circuit breaker's phase-selection closing under load according to the basic parameters; S3. Determine whether the actual insulation strength degradation rate of the circuit breaker's phase-selection closing under load meets the requirements of phase-selection closing operation. If it does not meet the requirements of phase-selection closing operation, give an alarm and end the process; if it meets the requirements of phase-selection closing operation, start S4; S4. Determine whether the mechanical dispersion of the circuit breaker meets the distribution range of the standard deviation of the closing time; if it meets the distribution range of the standard deviation, adjust the electrical closing target point of the phase-selection device; if it does not meet the distribution range of the standard deviation, start S5; S5. Determine whether the mechanical dispersion of the circuit breaker meets the range of the phase-selection closing limit requirements; If it does not meet the range of the phase-selection closing limit requirements, give an alarm and end the process; If it meets the range of the phase-selection closing limit requirements, then adjust the electrical closing target point of the phase-selection device.

2. The real-time control method for phase-selection closing of a circuit breaker according to claim 1, characterized in that, In S1, determine the actual electrical closing phase of the circuit breaker's phase-selection closing operation from the oscillogram of the circuit breaker's phase-selection closing with load ; From the time when the phase selection device issues the phase selection closing command to the time when the auxiliary contact feedbacks the closing signal, the closing time T of the auxiliary contact under load is obtained ECaux ; The closing time of the main contact and the closing time of the auxiliary contact are obtained through multiple closing characteristic tests of the circuit breaker under no-load conditions.

3. The real-time control method for selected-phase closing of a circuit breaker according to claim 2, characterized in that, In S2, calculating the actual insulation strength degradation rate of the circuit breaker's phase-selection closing under load according to the basic parameters is specifically as follows: First, calculate the closing time difference between the main contact and the auxiliary contact, and the calculation expression is: △ Caux =T Caux -T Cmain ; Among them, T Cmain is the closing time of the main contact, and T Caux is the closing time of the auxiliary contact. Δ Caux is the closing time difference between the main contact and the auxiliary contact; Based on the closing time T of the auxiliary contact when under load ECaux , and the closing time difference △ between the main contact and the auxiliary contact Caux , the closing time T of the main contact of the circuit breaker under load is calculated ECmain , and the expression is: T ECmain = T ECaux - △ Caux ; According to the actual electrical closing phase of the breaker's phase-selection closing and the closing time T of the breaker's main contact under load ECmain , calculate the actual insulation strength degradation rate of the breaker's phase-selection closing under load , and the expression is: ； ； Among them, U P is the peak value of the relative ground voltage; T pre is the pre-breakdown time; is the angular frequency corresponding to the power frequency; T is the power frequency period; N represents the maximum integer multiple of 1 / 2 power frequency period.

4. A real-time control method for circuit breaker phase-selection closing according to claim 1, characterized in that In S3, determining whether the actual insulation strength degradation rate of the circuit breaker's phase-selection closing under load meets the requirements of phase-selection closing operation is specifically as follows: Calculate the average value of insulation degradation rate RDDS by taking the actual insulation strength degradation rate of the circuit breaker during multiple on-load selected-phase closing ave ; Judge the average value of insulation degradation rate RDDS ave Whether it is less than the critical value of insulation degradation rate RDDS CD If RDDS ave <RDDS CD ,it is determined that the insulation strength degradation rate does not meet the requirements of the selected phase closing operation; if RDDS ave ≥RDDS CD ,it is determined that the insulation strength degradation rate meets the requirements of the selected phase closing operation.

5. A real-time control method for selected-phase closing of a circuit breaker according to claim 3, characterized in that S4 is specifically as follows: Obtain the sample standard deviation of mechanical dispersion based on the closing time of the main contact ; Judge the standard deviation of the mechanical dispersion sample Whether it is within the distribution range of the standard deviation of the closing time. If it is within the distribution range of the standard deviation of the closing time, the mechanical dispersion of the circuit breaker meets the engineering requirements, and the electrical closing target point of the phase selection device is adjusted; If it is not within the distribution range of the standard deviation of the closing time, then the mechanical dispersion of the circuit breaker does not meet the engineering requirements; The distribution range of the standard deviation of the closing time is -1 1.

6. The real-time control method for selected-phase switching on of a circuit breaker according to claim 5, characterized in that S5 is specifically as follows: Judge the standard deviation of the mechanical dispersion sample Whether it meets the range requirements of the selected in-phase closing limit; The limit requirement range of the selected-phase closing is ; Among them, is the angle at which the breaker's selected-phase closing deviates from the voltage zero-crossing point when triggering the commutation failure prediction and alarm of the DC system; is the angular frequency corresponding to the power frequency; When or , it is determined that the mechanical dispersion of the circuit breaker does not meet the limit requirements of the phase-selection closing, and the prediction alarm requirement for commutation failure is triggered; Standard deviation of mechanical dispersion of the sample If the mechanical dispersion meets the range requirements of the synchronous closing limit, the mechanical dispersion of the circuit breaker meets the requirements of not triggering the commutation failure prediction alarm, and the electrical closing target point of the phase selection device is adjusted.

7. A real-time control method for selected-phase closing of a circuit breaker according to claim 6, characterized in that, The calculation expression for adjusting the electrical closing target point of the phase-selection device is: ； Among them, is the closing phase correction coefficient, ; represents the actual electrical closing phase of the circuit breaker's phase-selection closing; sin() represents the sine function; The value is adjusted in real time according to statistical data, and the confidence interval of the value is within the range; represents the electrical closing target point of the phase selection device.

8. A real-time control system for phase-selection closing of a circuit breaker, which implements the real-time control method for phase-selection closing of the circuit breaker according to any one of claims 1-7, characterized in that, It includes: A data acquisition module for obtaining basic parameters, where the basic parameters include the actual electrical closing phase of the circuit breaker's phase-selection closing, the closing time of the auxiliary contact when under load, the closing time of the main contact, and the closing time of the auxiliary contact; An insulation strength degradation rate calculation module for calculating the actual insulation strength degradation rate of the circuit breaker's phase-selection closing under load according to the basic parameters; A first judgment module for judging whether the actual insulation strength degradation rate of the circuit breaker's phase-selection closing under load meets the requirements of phase-selection closing operation. If it does not meet the requirements of phase-selection closing operation, give an alarm and end the process; If it meets the requirements of phase-selection closing operation, start the second judgment module; A second judgment module for judging whether the mechanical dispersion of the circuit breaker meets the distribution range of the standard deviation of the closing time; if it meets the distribution range of the standard deviation, start the adjustment module; If it does not meet the distribution range of the standard deviation, start the third judgment module; A third judgment module for judging whether the mechanical dispersion of the circuit breaker meets the range of the phase-selection closing limit requirements; If it does not meet the range of the phase-selection closing limit requirements, give an alarm and end the process; If it meets the range of the phase-selection closing limit requirements, then start the adjustment module; An adjustment module for adjusting the electrical closing target point of the phase-selection device.

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the circuit breaker phase-selection closing real-time control method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the real-time control method for the circuit breaker's selected-phase closing as described in any one of claims 1 to 7.

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