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

Abstract

The present invention belongs to the technical field of circuit breakers, and relates to a real-time control method for phase selection and closing of circuit breakers and related devices. The control method is as follows: calculating the actual insulation strength drop rate of the circuit breaker's on-load phase selection closing according to basic parameters; judging whether the actual insulation strength drop rate of the circuit breaker's on-load phase selection closing meets the phase selection closing operation requirements, and if not, alarming; if the phase selection closing operation requirements are met, judging whether the mechanical dispersion of the circuit breaker meets the distribution range of the standard deviation of the closing time; if the distribution range of the standard deviation is met, adjusting the electrical closing target point of the phase selection device; if the distribution range of the standard deviation is not met, judging whether the mechanical dispersion of the circuit breaker meets the phase selection closing limit requirement range; if the phase selection closing limit requirement range is not met, alarming; if the phase selection closing limit requirement range is met, adjusting the electrical closing target point of the phase selection device. This solves the problem that the parameter settings of the phase selection closing device are solidified and the parameter adaptive adjustment cannot be achieved.

Description

Technical Field

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

[0002] AC filter circuit breakers are key components of the AC filter field in converter stations of UHVDC transmission systems. They operate by switching the AC filter circuit breaker on and off to compensate for reactive power and filter harmonics on the AC side of the system. They also regulate the AC bus voltage to ensure power quality.

[0003] Typically, single-phase AC filters in DC system converter stations have large capacity. Improper filter switching timing can result in significant inrush current and overvoltage. To mitigate the impact of inrush current on the AC system caused by the AC filter circuit breaker (when the filter is switched on), AC filter circuit breakers are typically equipped with phase closing devices. This controls the closing phase of the circuit breaker, ensuring that the circuit breaker is switched on near the voltage zero crossing point, effectively reducing the inrush current.

[0004] Commutation failure is one of the most common faults in DC transmission systems. Its primary cause is a drop in the AC bus voltage on the inverter side caused by an AC system fault. Excessive phase selection and closing deviation in the AC filter circuit breaker increases the closing inrush current, distorting the AC bus voltage waveform and shifting the natural commutation point forward, resulting in a smaller turn-off angle γ and causing commutation failure. Commutation failure can lead to adverse consequences such as reduced DC transmission power, lower voltage, increased current, shortened converter valve life, and even a DC outage.

[0005] DC systems generally use commutation failure predictive control to prevent commutation failures caused by AC faults. The mechanism is as follows: The DC control system detects AC bus voltage distortion and triggers the commutation failure predictive control function, causing the inverter to trigger prematurely, increasing the turn-off angle γ. This prevents commutation failures caused by AC disturbances due to a drop in the turn-off angle γ.

[0006] However, different phase selection and closing deviations of the AC filter circuit breaker result in different closing inrush currents, causing varying degrees of distortion in the AC bus voltage waveform. Even if the commutation failure predictive control function is activated, a larger increase in the turn-off angle γ and a greater drop in the DC voltage will also increase the AC bus voltage. Once this threshold is exceeded, commutation failure cannot be avoided. Therefore, rationally adjusting the parameters of the phase selection and closing device to minimize the phase selection and closing deviation can effectively prevent commutation failure.

[0007] The main factors affecting phase selection control accuracy include: mechanical dispersion of the circuit breaker; and rate of decrease of dielectric strength (RDDS). Because the mechanical characteristics and dielectric strength decrease rate of the AC filter circuit breaker in the converter station gradually change over time, the parameters of existing phase selection and closing devices are not adjusted after setup and acceptance. After a period of operation, the parameters of the phase selection and closing device are generally only manually adjusted based on the mechanical characteristics during maintenance. This parameter setting of the phase selection and closing device is subject to lag and insufficient precision control, leading to phase selection and closing deviations and even commutation failures in the DC transmission system. Summary of the Invention

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

[0009] The present invention is achieved through the following technical solutions:

[0010] The present invention discloses a real-time control method for phase selection and closing of a circuit breaker, comprising the following steps:

[0011] S1. Obtain basic parameters, including the actual electrical closing phase of the circuit breaker phase selection closing, auxiliary breaker closing time under load, main breaker closing time, and auxiliary breaker closing time;

[0012] S2. Calculate the actual insulation strength drop rate of the circuit breaker during on-load phase-selective closing based on basic parameters;

[0013] S3. Determine whether the actual insulation strength drop rate of the circuit breaker on-load phase-selective closing meets the phase-selective closing operation requirements. If not, an alarm is issued and the process ends.

[0014] If the phase selection and closing operation requirements are met, start S4;

[0015] S4. Determine whether the mechanical dispersion of the circuit breaker meets the distribution range of the standard deviation of the closing time; if so, adjust the electrical closing target point of the phase selection device;

[0016] If the distribution range of the standard deviation is not met, start S5;

[0017] S5. Determine whether the mechanical dispersion of the circuit breaker meets the phase selection and closing limit requirements;

[0018] If the phase selection closing limit requirement range is not met, an alarm will be issued and the process will end;

[0019] If the phase selection closing limit requirement range is met, adjust the electrical closing target point of the phase selection device.

[0020] Furthermore, in S1, the actual electrical closing phase α of the circuit breaker phase selection closing operation is determined based on the waveform of the circuit breaker on-load phase selection closing operation;

[0021] From the phase selection device sending the phase selection closing command to the auxiliary breaker feedback closing signal, the auxiliary breaker closing time T under load is obtained. ECaux ;

[0022] The main break closing time and auxiliary break closing time are obtained by performing multiple closing characteristic tests of the circuit breaker under no-load conditions.

[0023] Furthermore, the actual insulation strength drop rate of the circuit breaker during on-load phase-selective closing is calculated based on the basic parameters, specifically:

[0024] First calculate the closing time difference between the main breaker and the auxiliary breaker. The calculation expression is:

[0025] △ Caux =T Caux -T Cmain ;

[0026] Among them, T Cmain Main breaker closing time, T Caux is the auxiliary breaker closing time, △ Caux The closing time difference between the main breaker and the auxiliary breaker;

[0027] Based on the auxiliary breaker closing time T under load ECaux , and the closing time difference between the main breaker and the auxiliary breaker △ Caux , calculate the closing time T of the circuit breaker with load ECmain , the expression is:

[0028] T ECmain =T ECaux -△ Caux ;

[0029] Actual electrical closing phase according to the circuit breaker phase selection closing And the closing time of the circuit breaker with load main break T ECmain , calculate the actual insulation strength drop rate of the circuit breaker with load phase selection closing , the expression is:

[0030] ;

[0031] ;

[0032] Among them, U P is the relative ground voltage peak; 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.

[0033] Furthermore, it is determined whether the actual insulation strength drop rate of the circuit breaker during on-load phase-selective closing meets the phase-selective closing operation requirements, specifically:

[0034] The average insulation strength drop rate RDDS is calculated by taking the actual insulation strength drop rate of multiple circuit breaker load phase selection closing ave ;

[0035] Determine the average insulation degradation rate RDDS ave Is it less than the insulation degradation rate critical value RDDS? CD , if RDDS ave <RDDS CD , it is determined that the insulation strength drop rate does not meet the phase selection and closing operation requirements; if RDDS ave ≥RDDS CD , it is determined that the insulation strength drop rate meets the phase selection and closing operation requirements.

[0036] Furthermore, S4 is specifically:

[0037] The standard deviation of the mechanical dispersion samples is obtained based on the main breaker closing time. ;

[0038] Determine the standard deviation of mechanical dispersion samples Is the closing time standard deviation within the distribution range? If so, the mechanical dispersion of the circuit breaker meets the project requirements, and the electrical closing target point of the phase selection device should be adjusted. If not, the mechanical dispersion of the circuit breaker does not meet the project requirements.

[0039] The distribution range of the standard deviation of the closing time is -1 1.

[0040] Furthermore, S5 is specifically:

[0041] Determine the standard deviation of mechanical dispersion samples Whether the phase selection and closing limit requirements are met;

[0042] The phase selection closing limit requirement range is ;

[0043] in, The angle at which the circuit breaker phase selection and closing deviates from the voltage zero crossing point when triggering the DC system commutation failure prediction alarm; is the angular frequency corresponding to the power frequency;

[0044] when or , it is determined that the mechanical dispersion of the circuit breaker does not meet the phase selection and closing limit requirements, triggering the phase change failure prediction alarm requirement;

[0045] Mechanical dispersion sample standard deviation If the phase selection closing limit requirement range is met, the mechanical dispersion of the circuit breaker meets the requirement of not triggering the phase change failure prediction alarm, and the electrical closing target point of the phase selection device is adjusted.

[0046] Furthermore, the calculation expression for adjusting the electrical closing target point of the phase selection device is:

[0047] ;

[0048] in, is the closing phase correction coefficient, ;sin() represents the sine function;

[0049] The value is adjusted in real time based on statistical data, and The confidence interval of the value is within the scope; Represents the electrical closing target point of the phase selection device.

[0050] The present invention also discloses a circuit breaker phase selection and closing real-time control system, comprising:

[0051] A data acquisition module is used to obtain basic parameters, including the actual electrical closing phase of the circuit breaker phase selection closing, the auxiliary break closing time under load, the main break closing time and the auxiliary break closing time;

[0052] The insulation strength degradation rate calculation module is used to calculate the actual insulation strength degradation rate of the circuit breaker on-load phase selection closing according to basic parameters;

[0053] The first judgment module is used to judge whether the actual insulation strength drop rate of the circuit breaker on-load phase-selective closing meets the phase-selective closing operation requirements. If it does not meet the phase-selective closing operation requirements, an alarm is issued and the process ends;

[0054] If the phase selection and closing operation requirements are met, the second judgment module is started;

[0055] The second judgment module is used 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, the adjustment module is started;

[0056] If the distribution range of the standard deviation is not met, the third judgment module is activated;

[0057] The third judgment module is used to judge whether the mechanical dispersion of the circuit breaker meets the phase selection closing limit requirement range;

[0058] If the phase selection closing limit requirement range is not met, an alarm will be issued and the process will end;

[0059] If the phase selection closing limit requirement range is met, the adjustment module is started;

[0060] The adjustment module is used to adjust the electrical closing target point of the phase selection device.

[0061] The present invention also discloses a computer device, comprising 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 circuit breaker phase selection and closing real-time control method is implemented.

[0062] The present invention also discloses a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the circuit breaker phase selection and closing real-time control method is implemented.

[0063] Compared with the prior art, the present invention has the following beneficial technical effects:

[0064] The present invention discloses a real-time control method for phase-selective closing of a circuit breaker. The method first accurately calculates the actual insulation strength drop rate of the circuit breaker during phase-selective closing based on basic parameters. When the operating requirements for phase-selective closing are met, the range of mechanical dispersion variation of the circuit breaker is calculated to determine whether the mechanical dispersion variation of the circuit breaker meets the standard deviation distribution range. If so, the electrical closing target point of the phase-selective device can be directly adjusted. If not, the method further determines whether the mechanical dispersion of the circuit breaker meets the phase-selective closing limit requirement range. If the mechanical dispersion of the circuit breaker does not meet the phase-selective closing limit requirement range, an alarm is issued. If the mechanical dispersion of the circuit breaker meets the phase-selective closing limit requirement range, the electrical closing target point of the phase-selective device can be adjusted to ensure that the mechanical dispersion of the circuit breaker deviates from the engineering requirement value without triggering a phase-change failure prediction alarm. The electrical closing target point of the phase-selective device is adjusted in real time as the actual insulation strength drop rate of phase-selective closing and the mechanical dispersion of the circuit breaker change. The method of the present invention is simple, reliable and highly practical, effectively improves the phase selection and closing control accuracy, eliminates the limitation of human factors in determining the optimal closing phase, and effectively suppresses the DC system commutation failure caused by AC voltage waveform distortion caused by phase selection and closing deviation.

[0065] Furthermore, in the process of judging whether the actual insulation strength reduction rate of the circuit breaker during on-load phase-selective closing meets the phase-selective closing operation requirements, a critical value of the insulation strength reduction rate is introduced, and the average value of the actual insulation reduction rate of the circuit breaker and the critical value of the insulation strength reduction rate are compared in real time to judge whether the actual insulation reduction rate of the circuit breaker meets the phase-selective closing requirements, thereby realizing a status assessment of the actual operating insulation reduction rate of the circuit breaker.

[0066] Furthermore, the present invention determines the phase selection closing limit requirement range based on the phase selection phase deviation angle when the commutation failure prediction alarm is triggered, controls the closing phase setting value of the phase selection closing device within the mechanical dispersion limit value range, and determines whether the mechanical dispersion sample standard deviation meets the phase selection closing limit requirement range. If so, the phase selection closing deviation is effectively controlled so that it does not trigger the commutation failure prediction alarm. If not, it is determined that the mechanical dispersion of the circuit breaker does not meet the phase selection closing limit requirement range, and the commutation failure prediction alarm requirement is triggered.

[0067] Furthermore, the present invention obtains the actual insulation strength decrease rate of the circuit breaker's on-load phase-selective closing according to the actual closing phase and mechanical closing time of the circuit breaker's phase-selective closing. According to the change in the insulation strength decrease rate and the dispersion of mechanical closing, a closing phase correction coefficient is introduced to adjust the closing phase setting value of the phase selection device in real time, thereby realizing precise control of the phase selection closing and reducing the phase selection closing deviation. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 This is a flow chart of a circuit breaker phase selection and closing real-time control method of the present invention;

[0069] Figure 2 This is a schematic diagram of a circuit breaker phase selection and closing real-time control system of the present invention;

[0070] Figure 3 To meet the slope requirement of insulation drop rate for phase selection and closing conditions;

[0071] Figure 4 The dispersion of the electrical closing target point is caused by the dispersion of the insulation drop rate;

[0072] Figure 5 The dispersion of electrical closing target points caused by mechanical dispersion;

[0073] Figure 6 The phase selection closing limit requirement range is determined based on the phase selection closing angle that triggers the phase commutation failure prediction alarm. DETAILED DESCRIPTION

[0074] In order to make the purpose, technical solutions and advantages of the present invention more clear, the following is a further detailed description with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. That is, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments.

[0075] The detailed description of the embodiment of the present invention provided in the following figures is not intended to limit the scope of the claimed invention, but merely represents a selected embodiment of the present invention. All other embodiments derived by those skilled in the art based on the figures and embodiments of the present invention without inventive effort shall fall within the scope of protection of the present invention.

[0076] Explanation of relevant technical terms:

[0077] AC filter circuit breaker: A circuit breaker that, in a high-voltage direct current transmission system, can carry and frequently open and close the rated current of the AC filter circuit and the reactive compensation capacitor circuit, close the inrush current of the back-to-back capacitor bank, and has the rated short-circuit current making and breaking capacity under specified operating conditions.

[0078] Phase selection closing: During the closing process of the circuit breaker, there are certain specific phases, so that if the circuit breaker is electrically closed at this moment, the closing transient process can achieve a smoother transition, reducing transient inrush current or overvoltage shock to improve system stability.

[0079] Commutation failure: In the converter, if the valve that has been shut down fails to restore its blocking capacity within a period of time under the action of reverse voltage, or the commutation process is not completed during the reverse voltage period, then when the valve voltage becomes positive, the valve being commutated will reverse its phase to the valve that was originally scheduled to be shut down. This situation is called commutation failure.

[0080] Closing inrush current: In a power system, when a capacitor is put into operation, a closing inrush current is generated at the moment of closing.

[0081] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0082] Example 1

[0083] like Figure 1 As shown, the present invention discloses a real-time control method for phase selection and closing, comprising the following steps:

[0084] S1. Obtain basic parameters, including the actual electrical closing phase of the circuit breaker phase selection closing, auxiliary breaker closing time under load, main breaker closing time, and auxiliary breaker closing time;

[0085] S2. Calculate the actual insulation strength drop rate of the circuit breaker during on-load phase-selective closing based on basic parameters;

[0086] S3. Determine whether the actual insulation strength drop rate of the circuit breaker on-load phase-selective closing meets the phase-selective closing operation requirements. If not, an alarm is issued and the process ends.

[0087] If the phase selection and closing operation requirements are met, start S4;

[0088] S4. Determine whether the mechanical dispersion of the circuit breaker meets the distribution range of the standard deviation of the closing time; if so, adjust the electrical closing target point of the phase selection device;

[0089] If the distribution range of the standard deviation is not met, start S5;

[0090] S5. Determine whether the mechanical dispersion of the circuit breaker meets the phase selection and closing limit requirements;

[0091] If the phase selection closing limit requirement range is not met, an alarm will be issued and the process will end;

[0092] If the phase selection closing limit requirement range is met, it means that the mechanical dispersion of the circuit breaker meets the requirement of not triggering the phase change failure prediction alarm, and the electrical closing target point of the phase selection device is adjusted.

[0093] The present invention accurately calculates the actual insulation strength decrease rate of the circuit breaker's on-load phase-selective closing based on the measured data of phase-selective closing, and counts the range of change of the circuit breaker's mechanical dispersion in real time. Then, logical judgment is made based on the changes of the two. Finally, it is judged in sequence whether the actual insulation strength decrease rate of the circuit breaker's on-load phase-selective closing meets the phase-selective closing operation requirements, 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 phase-change failure prediction alarm deviation requirements.

[0094] The relationship between the phase selection device and the circuit breaker:

[0095] Phase-selective opening and closing technology, also known as phase-controlled technology, is a technology in which a phase-selector device controls the opening and closing of circuit breakers, enabling the circuit breaker to close or open at a predetermined voltage or current phase, achieving a smooth transition of the opening and closing transient process, thereby reducing the impact of transient inrush current or overvoltage on equipment and systems and improving system stability.

[0096] Example 2

[0097] On the basis of Example 1, in S1, the circuit breaker performs multiple closing characteristic tests under no-load conditions to obtain the main breaker closing time T Cmain and auxiliary breaker closing time T Caux .

[0098] In multiple closing characteristic tests, the starting position, ending position and middle position of the auxiliary switch are selected to test their respective closing times, and the auxiliary contacts with relatively stable closing time difference between the main break and the auxiliary break are selected as the phase-selecting closing auxiliary contacts.

[0099] Auxiliary switches are typically linked to the circuit breaker's main contacts to reflect the breaker's open and closed states. The starting position generally refers to the auxiliary switch's initial state before the circuit breaker closes; the ending position is the final state after the closing action; and the intermediate position represents the intermediate transition states the auxiliary switch passes through during the closing process. Measuring the closing time at these three positions provides a more detailed understanding of the auxiliary switch's operation throughout the closing process, allowing analysis of whether the circuit breaker's closing characteristics meet requirements.

[0100] Determine the actual electrical closing phase of the circuit breaker phase selection closing operation from the circuit breaker load phase selection closing operation recording diagram .

[0101] From the phase selection device sending out the phase selection closing command to the phase selection closing auxiliary contact feeding back the closing signal, the auxiliary breaker closing time T under load is obtained. ECaux .

[0102] Example 3

[0103] Based on Example 2, S2 is specifically:

[0104] First calculate the closing time difference between the main breaker and the auxiliary breaker △ Caux , the expression is:

[0105] △ Caux =T Caux -T Cmain ;

[0106] Based on the auxiliary contact closing time T of the auxiliary break under load obtained in step 1 ECaux The closing time difference between the main breaker and the auxiliary breaker △ Caux , calculate the closing time T of the circuit breaker with load ECmain , the expression is:

[0107] T ECmain =T ECaux -△ Caux .

[0108] Actual electrical closing phase according to the circuit breaker phase selection closing And the closing time of the circuit breaker with load main break T ECmain , calculate the actual insulation strength drop rate of the circuit breaker with load phase selection closing , the expression is:

[0109] ;

[0110] ;

[0111] Among them, U P is the relative ground voltage peak value, in kV; Tpre is the pre-breakdown time, in ms; is the angular frequency corresponding to the power frequency, in rad / ms; is the maximum integer multiple of 1 / 2 power frequency cycle, T is the power frequency cycle; the actual electrical closing phase α of the circuit breaker phase selection closing is adjusted in real time according to the measured value; is the pre-breakdown time.

[0112] Record the actual insulation strength drop rate RDDS for each phase-selected closing of the circuit breaker under load real , compared with the insulation strength reduction rate RDDS real this time and the last insulation strength decrease rate RDDS real last time , the insulation strength decrease rate with a smaller value (smaller slope) is selected as the basis parameter for setting the electrical closing target phase of the phase selection device.

[0113] S3 is specifically: the actual insulation strength reduction rate RDDS of the circuit breaker with load phase selection closing for the past five times real , find its average value RDDS ave , such as RDDS ave <RDDS CD , it is determined that the insulation strength drop rate of the circuit breaker does not meet the circuit breaker phase selection and closing operation requirements, and the control system sends an alarm signal or message to the control and protection.

[0114] Among them, RDDS CD is the critical value of insulation degradation rate, RDDS CD .

[0115] If RDDS ave ≥RDDS CD , it is determined that the insulation strength drop rate meets the phase selection and closing operation requirements.

[0116] The method of the present invention introduces the critical value of the rate of decrease of dielectric strength RDDS CD , the actual insulation strength drop rate of the circuit breaker is evaluated. By selecting 5 times of circuit breaker on-load phase selection closing actual insulation strength drop rate RDDS real Calculate the average value and compare it with the average value of the insulation strength reduction rate RDDS ave and the critical value of dielectric strength reduction rate RDDS CD , give a judgment. When RDDS ave <RDDS CD When the circuit breaker RDDS does not meet the operation requirements, the system alarms and exits operation; when the RDDS ave ≥RDDS CD When the breaker RDDS changes, check and adjust the closing phase setting value of the phase selection device. The specific reasoning is as follows:

[0117] The slope of the circuit breaker RDDS must be greater than the critical point slope (peak value is U P The actual optimal closing time will lag behind the theoretical reference voltage zero crossing point. Figure 1 As shown in RDDS1, the arc begins at point B when it intersects the reference voltage. TD2 is the time interval from the voltage zero crossing to arc initiation, and TD3 is the pre-arcing time, which is the time interval from arc initiation at the break to final contact of the switch contacts. The actual closing time is Tc. In this case, the voltage at switch arc initiation is low, and the inrush current is minimal. Furthermore, because TD2 and TD3 are very small, even if RDDS1 deviates slightly, the closing time will not fluctuate significantly, ensuring good stability.

[0118] The slope of the circuit breaker RDDS is less than the critical point slope, which is affected by mechanical dispersion, e.g. Figure 3 As shown in RDDS2 in Figure 1, the RDDS curve may intersect the reference voltage at point A before the voltage reaches zero, initiating arcing. Because the voltage at this point is near its peak and the inrush current is large, it can easily cause AC voltage waveform distortion and lead to DC system commutation failure. Therefore, the circuit breaker's RDDS slope must be greater than the critical slope.

[0119] Example 4

[0120] On the basis of Example 3, S4 is specifically:

[0121] Record and count the main breaker closing time T Cmain , the conventional calculation method of mathematical statistics is used to obtain the average value of mechanical closing time and the standard deviation of mechanical dispersion samples. , according to the distribution range of the standard deviation of the closing time, the closing voltage phase of the phase selection device is adjusted.

[0122] The distribution range of the standard deviation of the closing time is -1 1. If it is within this distribution range, the mechanical dispersion of the circuit breaker meets the engineering requirements, and the electrical closing target point of the phase selection device can be directly adjusted; if >1 or <-1, the mechanical dispersion of the circuit breaker does not meet the engineering requirements.

[0123] Example 5

[0124] Based on Example 4, S5 is specifically:

[0125] When the mechanical dispersion of the circuit breaker does not meet the engineering requirements, in order to avoid the AC voltage distortion caused by the circuit breaker phase selection and closing deviation triggering the DC system commutation failure prediction alarm, it is necessary to use , that is, the mechanical dispersion of the circuit breaker without triggering the DC system commutation failure prediction alarm should meet the phase selection closing limit requirement range:

[0126] ;

[0127] in, The angle at which the circuit breaker phase selection and closing deviates from the voltage zero crossing point when triggering the DC system commutation failure prediction alarm.

[0128] When the mechanical dispersion of the circuit breaker or , it is determined that the mechanical dispersion does not meet the phase selection and closing operation requirements of the circuit breaker, and the control system sends an alarm signal or message to the control and protection, and triggers the DC system commutation failure prediction alarm.

[0129] According to the closing time T of the main disconnect port of the circuit breaker ECmain , the mechanical dispersion sample standard deviation σ and the phase deviation of the selected phase when the commutation failure prediction alarm is not triggered, we can get:

[0130] The time T when the mechanical closing target point of the phase selection device deviates from the voltage zero point shift for:

[0131] T shift =β ;

[0132] When the mechanical dispersion of the circuit breaker meets the requirement of not triggering the commutation failure prediction alarm, Calculate the electrical closing target point of the phase selection device , the calculation expression is:

[0133] ;

[0134] in, is the closing phase correction coefficient, ;sin() represents the sine function;

[0135] The value is adjusted in real time based on statistical data, but The confidence interval for the value cannot exceed scope;

[0136] Phase selection device electrical closing target point The adjustment is based on the smaller value of the slope of the insulation strength decrease rate determined in Example 3. , the actual electrical closing phase of the circuit breaker phase selection closing and the standard deviation of multiple consecutive mechanical dispersion samples Decisions are made and revised continuously according to changes.

[0137] In the present invention, the actual electrical closing phase of the circuit breaker is selected according to the phase of the circuit breaker. And the closing time of the circuit breaker with load main break TECmain , the actual insulation strength drop rate of the circuit breaker is obtained; according to the change of insulation strength drop rate and the change of mechanical closing dispersion, the closing phase correction coefficient is introduced to adjust the closing phase setting value of the phase selection device in real time, realizing precise control of phase selection closing and reducing phase selection closing deviation. The specific reasoning is as follows:

[0138] The statistical characteristics of dielectric breakdown have an important influence on the rate of dielectric strength degradation. The actual rate of dielectric strength degradation will show a certain degree of dispersion. Figure 4 As shown in Figure 1, the electrical closing target point of the phase selection device varies under different insulation strength drop rates. Real-time adjustment of the electrical closing target point of the phase selection device based on the change in the circuit breaker RDDS helps achieve precise control of phase selection and closing.

[0139] The mechanical dispersion of the circuit breaker will inevitably change during long-term operation due to the influence of control voltage, ambient temperature, mechanism oil pressure, air pressure, and action interval time. Figure 5 As shown in Figure 1, the electrical closing target points of phase selectors with different mechanical dispersions are also different. Adjusting the electrical closing target points of the phase selector in real time based on the changes in the mechanical dispersion of the circuit breaker helps achieve precise control of phase selection and closing.

[0140] The present invention determines the phase selection closing limit requirement range according to the phase selection related closing phase deviation angle when triggering the phase change failure prediction alarm, controls the closing phase setting value of the phase selection closing device within the phase selection closing limit requirement range, and effectively controls the phase selection closing deviation so that it will not trigger the phase change failure prediction alarm.

[0141] When the commutation failure prediction alarm is issued, the relevant phase deviation angle range is selected. The minimum deviation angle is used as the limit value of the control mechanical dispersion range. Figure 6 As shown, when or When the mechanical dispersion of the circuit breaker is very likely to trigger the phase change failure prediction alarm, the operation requirements are not met, the system alarms, and the operation is stopped; when When the phase selection device is closed, the closing target point is adjusted according to the change of the mechanical dispersion of the circuit breaker.

[0142] In summary, the present invention uses the closing time difference △ between the main break and the auxiliary break of the circuit breaker caux The actual electrical closing phase measured by the phase selector is used to determine the actual closing time of the circuit breaker and accurately calculate the actual dielectric strength drop rate during on-load phase-selective closing of the circuit breaker. A closing phase correction factor is introduced based on changes in mechanical dispersion. By adjusting the correction factor, the electrical closing target point of the phase selector can be corrected in real time. Simultaneously, logical judgment is performed on the actual dielectric strength drop rate during on-load phase-selective closing of the circuit breaker and the real-time statistical changes in the mechanical dispersion of the circuit breaker, providing an operational and maintenance basis for phase-selective closing of the AC filter circuit breaker in the converter station.

[0143] like Figure 2 As shown, the present invention also discloses a circuit breaker phase selection and closing real-time control system, comprising:

[0144] A data acquisition module is used to obtain basic parameters, including the actual electrical closing phase of the circuit breaker phase selection closing, the auxiliary break closing time under load, the main break closing time and the auxiliary break closing time;

[0145] The insulation strength degradation rate calculation module is used to calculate the actual insulation strength degradation rate of the circuit breaker on-load phase selection closing according to basic parameters;

[0146] The first judgment module is used to judge whether the actual insulation strength drop rate of the circuit breaker on-load phase-selective closing meets the phase-selective closing operation requirements. If it does not meet the phase-selective closing operation requirements, an alarm is issued and the process ends;

[0147] If the phase selection and closing operation requirements are met, the second judgment module is started;

[0148] The second judgment module is used 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, the adjustment module is started;

[0149] If the distribution range of the standard deviation is not met, the third judgment module is activated;

[0150] The third judgment module is used to judge whether the mechanical dispersion of the circuit breaker meets the phase selection closing limit requirement range;

[0151] If the phase selection closing limit requirement range is not met, an alarm will be issued and the process will end;

[0152] If the phase selection closing limit requirement range is met, the mechanical dispersion of the circuit breaker meets the requirement of not triggering the phase change failure prediction alarm, and the adjustment module is started;

[0153] The adjustment module is used to adjust the electrical closing target point of the phase selection device.

[0154] The present invention also discloses a computer device comprising 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 circuit breaker phase selection and closing real-time control method is implemented. The memory may include internal memory, such as a high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device. The processor, network interface, and memory are interconnected via an internal bus. The internal bus may be an industrial standard architecture bus, a peripheral component interconnect standard bus, an extended industrial standard architecture bus, etc. The bus may 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 operating instructions. The memory may include internal memory and non-volatile memory, and provides instructions and data to the processor.

[0155] The present invention also discloses a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the circuit breaker phase selection and closing real-time control method. 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 disk, magnetic disk, etc.

[0156] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, optical storage, etc.) containing computer-usable program code.

[0157] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0158] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0159] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0160] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A real-time control method for phase selection and closing of a circuit breaker, characterized in that: The following steps are involved: S1. Obtain basic parameters, including the actual electrical closing phase of the circuit breaker phase selection closing, auxiliary breaker closing time under load, main breaker closing time, and auxiliary breaker closing time; S2. Calculate the actual insulation strength drop rate of the circuit breaker during on-load phase-selective closing based on basic parameters; S3: Determine whether the actual insulation strength drop rate of the circuit breaker on-load phase-selective closing meets the phase-selective closing operation requirements. If not, an alarm is issued and the process ends. If it meets the phase-selective closing operation requirements, S4 is started. S4: Determine whether the mechanical dispersion of the circuit breaker meets the distribution range of the standard deviation of the closing time; if so, adjust the electrical closing target point of the phase selection device; if not, start S5; S5. Determine whether the mechanical dispersion of the circuit breaker meets the phase selection and closing limit requirements; If the phase selection closing limit requirement range is not met, an alarm will be issued and the process will end; If the phase selection closing limit requirement range is met, adjust the electrical closing target point of the phase selection device; In S1, the actual electrical closing phase of the circuit breaker phase selection closing operation is determined by the circuit breaker load phase selection closing operation recording diagram. ; From the phase selection device sending the phase selection closing command to the auxiliary breaker feedback closing signal, the auxiliary breaker closing time T under load is obtained. ECaux ; The main break closing time and auxiliary break closing time are obtained by performing multiple closing characteristic tests of the circuit breaker under no-load conditions; In S2, the actual insulation strength drop rate of the circuit breaker with load phase selection closing is calculated based on the basic parameters, specifically: First calculate the closing time difference between the main breaker and the auxiliary breaker. The calculation expression is: △ Caux =T Caux -T Cmain ; Among them, T Cmain Main breaker closing time, T Caux is the auxiliary breaker closing time, △ Caux The closing time difference between the main breaker and the auxiliary breaker; Based on the auxiliary breaker closing time T under load ECaux , and the closing time difference between the main breaker and the auxiliary breaker △ Caux , calculate the closing time T of the circuit breaker with load ECmain , the expression is: T ECmain =T ECaux -△ Caux ; Actual electrical closing phase according to the circuit breaker phase selection closing And the closing time of the circuit breaker with load main break T ECmain , calculate the actual insulation strength drop rate of the circuit breaker with load phase selection closing , the expression is: ； ； Among them, U P is the relative ground voltage peak; 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.

2. A circuit breaker phase selection and closing real-time control method according to claim 1, characterized in that: In S3, it is determined whether the actual insulation strength drop rate of the circuit breaker on-load phase-selective closing meets the phase-selective closing operation requirements, specifically: The average insulation strength drop rate RDDS is calculated by taking the actual insulation strength drop rate of multiple circuit breaker load phase selection closing ave ; Determine the average insulation degradation rate RDDS ave Is it less than the insulation degradation rate critical value RDDS? CD , if RDDS ave <RDDS CD , it is determined that the insulation strength drop rate does not meet the phase selection and closing operation requirements; if RDDS ave ≥RDDS CD , it is determined that the insulation strength drop rate meets the phase selection and closing operation requirements.

3. A circuit breaker phase selection and closing real-time control method according to claim 1, characterized in that: S4 is specifically: The standard deviation of the mechanical dispersion samples is obtained based on the main breaker closing time. ; Determine the standard deviation of mechanical dispersion samples Is the closing time standard deviation within the distribution range? If so, the mechanical dispersion of the circuit breaker meets the engineering requirements, and the electrical closing target point of the phase selection device should be 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.

4. A circuit breaker phase selection and closing real-time control method according to claim 3, characterized in that: S5 is specifically: Determine the standard deviation of mechanical dispersion samples Whether the phase selection and closing limit requirements are met; The phase selection closing limit requirement range is ; in, The angle at which the circuit breaker phase selection and closing deviates from the voltage zero crossing point when triggering the DC system commutation failure prediction alarm; 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 phase selection and closing limit requirements, triggering the phase change failure prediction alarm requirement; If the standard deviation of the mechanical dispersion sample If the phase selection closing limit requirement range is met, the mechanical dispersion of the circuit breaker meets the requirement of not triggering the phase change failure prediction alarm, and the electrical closing target point of the phase selection device is adjusted.

5. A circuit breaker phase selection and closing real-time control method according to claim 4, characterized in that: The calculation expression for adjusting the electrical closing target point of the phase selection device is: ； in, is the closing phase correction coefficient, ; Represents the actual electrical closing phase of the circuit breaker phase selection closing; sin() represents the sine function; The value is adjusted in real time based on statistical data, and The confidence interval of the value is within the scope; Represents the electrical closing target point of the phase selection device.

6. A circuit breaker phase selection and closing real-time control system, which implements the circuit breaker phase selection and closing real-time control method according to any one of claims 1 to 5, characterized in that: include: A data acquisition module is used to obtain basic parameters, including the actual electrical closing phase of the circuit breaker phase selection closing, the auxiliary break closing time under load, the main break closing time and the auxiliary break closing time; The insulation strength degradation rate calculation module is used to calculate the actual insulation strength degradation rate of the circuit breaker on-load phase selection closing according to basic parameters; The first judgment module is used to judge whether the actual insulation strength drop rate of the circuit breaker on-load phase-selective closing meets the phase-selective closing operation requirements. If it does not meet the phase-selective closing operation requirements, an alarm is issued and the process ends; If the phase selection and closing operation requirements are met, the second judgment module is started; The second judgment module is used 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, the adjustment module is started; If the distribution range of the standard deviation is not met, the third judgment module is activated; The third judgment module is used to judge whether the mechanical dispersion of the circuit breaker meets the phase selection closing limit requirement range; If the phase selection closing limit requirement range is not met, an alarm will be issued and the process will end; If the phase selection closing limit requirement range is met, the adjustment module is started; The adjustment module is used to adjust the electrical closing target point of the phase selection device.

7. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the circuit breaker phase selection and closing real-time control method according to any one of claims 1 to 5 is implemented.

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the circuit breaker phase selection and closing real-time control method according to any one of claims 1 to 5 is implemented.

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