CN117833221A - Method and device for determining triggering time of event in power system - Google Patents
Method and device for determining triggering time of event in power system Download PDFInfo
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Abstract
The invention provides a method and a device for determining the triggering time of an event in a power system, wherein the method comprises the following steps: if the occurrence of an event is identified, acquiring sampling values of electrical parameters of the power system in the first M periods of the initial trigger time of the event, wherein the electrical parameters are one of current or voltage, and one period is equal to one cycle of the electrical parameters; determining an actual waveform of the electrical parameter in the first M periods according to the acquired sampling value of the electrical parameter; determining an upper limit envelope and a lower limit envelope of the electrical parameter over the first M cycles, the upper limit envelope and the lower limit envelope each determined based on fundamental waves and harmonics of the electrical parameter; and determining the final trigger time of the event according to the actual waveform, the upper limit envelope curve and the lower limit envelope curve.
Description
Technical Field
The invention relates to the field of power systems, in particular to a method and a device for determining trigger time of an event in a power system.
Background
The fault recorder is used for the power system, can automatically and accurately record the change of various electric quantities in the process before and after the fault event when the power system has the fault event, and has important functions of analyzing and processing the fault event, judging whether the protection is correctly operated and improving the safe operation level of the power system through analysis and comparison of the electric quantities.
When the fault recorder triggers fault recording, data before a fault event is acquired from the cache, the data after the fault event occurs and the data after the fault event is finished are stored as a complete recording, and the complete recording corresponds to a fault event. Therefore, the trigger time of the fault event needs to be determined very precisely, so that a complete record of the fault can be obtained.
Disclosure of Invention
In view of the above, the present invention proposes a method for determining a trigger time of an event in a power system, comprising:
if the occurrence of an event is identified, acquiring sampling values of electrical parameters of the power system in the first M periods of the initial trigger time of the event, wherein the electrical parameters are one of current or voltage, and one period is equal to one cycle of the electrical parameters;
determining an actual waveform of the electrical parameter in the first M periods according to the acquired sampling value of the electrical parameter;
determining an upper limit envelope and a lower limit envelope of the electrical parameter over the first M cycles, the upper limit envelope and the lower limit envelope each determined based on fundamental waves and harmonics of the electrical parameter;
and determining the final trigger time of the event according to the actual waveform, the upper limit envelope curve and the lower limit envelope curve.
According to the determination method as described above, optionally, determining the upper limit envelope and the lower limit envelope of the electrical parameter in the first M periods includes:
determining an upper and lower envelope of the electrical parameter for the first M cycles according to the following formula:
upper envelope = Ref (t) +delta,
lower envelope = Ref (t) -delta,
wherein F is 0 Is the effective value of the fundamental wave of the electrical parameter, f is the frequency of the power system, t is the sampling time, H n Is the effective value of the N-order harmonic of the electrical parameter, N is the highest harmonic that can be detected,the phase angle of the zero crossing point of the fundamental wave corresponding to the n-order harmonic wave is shown, and delta is a preset threshold value.
According to the determining method as described above, optionally, determining the final trigger time of the event according to the actual waveform, the upper limit envelope, and the lower limit envelope includes:
judging whether the actual waveform exceeds the range of the upper limit envelope curve and the lower limit envelope curve;
if the judging results are yes, updating the initial time when the actual waveform exceeds the range of the upper limit envelope curve and the lower limit envelope curve to the final trigger time of the event.
According to the determination method as described above, optionally, before acquiring the sampled values of the electrical parameter of the electrical power system in the first M periods of the trigger time of the event initiation, the method further includes:
determining the current fundamental wave phase angle of the electrical parameter;
if the current fundamental wave phase angle is between-180 DEG and 0 DEG, the M is 1.5;
if the current fundamental phase angle is between 0 ° and 180 °, then M is 1.
According to the determination method as described above, optionally, determining the current fundamental phase angle of the electrical parameter includes:
and determining the current fundamental wave phase angle of the electrical parameter according to the electrical parameter of the first Q periods of the initial trigger time of the event.
According to the determining method as described above, optionally, after determining the final trigger time of the event according to the actual waveform, the upper limit envelope, and the lower limit envelope, the method further includes:
and acquiring fault wave recording data corresponding to the event according to the final trigger time.
The invention also provides a device for determining the triggering time of an event in a power system, which comprises:
the first acquisition unit is used for acquiring sampling values of electrical parameters of the power system in the first M periods of the initial trigger time of the event if the event is identified, wherein the electrical parameters are one of current and voltage, and one period is equal to one cycle of the electrical parameters;
a first determining unit, configured to determine an actual waveform of the electrical parameter in the first M periods according to the acquired sampling value of the electrical parameter;
a second determining unit configured to determine an upper limit envelope and a lower limit envelope of the electrical parameter in the first M periods, each of the upper limit envelope and the lower limit envelope being determined based on fundamental waves and harmonics of the electrical parameter;
and the third determining unit is used for determining the final trigger time of the event according to the actual waveform, the upper limit envelope curve and the lower limit envelope curve.
According to the apparatus as described above, optionally, the second determining unit is configured to:
determining an upper and lower envelope of the electrical parameter for the first M cycles according to the following formula:
upper envelope = Ref (t) +delta,
lower envelope = Ref (t) -delta,
wherein F is 0 Is the effective value of the fundamental wave of the electrical parameter, f is the frequency of the power system, t is the sampling time, H n Is the effective value of the N-order harmonic of the electrical parameter, N is the highest harmonic that can be detected,corresponding to the n-th harmonicThe phase angle of the zero crossing point of the fundamental wave, delta is a preset threshold value.
According to the apparatus as described above, optionally, a fourth determining unit is further included, the fourth determining unit being configured to:
determining the current fundamental wave phase angle of the electrical parameter;
if the current fundamental wave phase angle is between-180 DEG and 0 DEG, the M is 1.5;
if the current fundamental phase angle is between 0 ° and 180 °, then M is 1.
The invention also provides a device for determining the triggering time of an event in a power system, which comprises:
at least one memory for storing instructions;
at least one processor for executing the method of determining the trigger moment of an event in a power system as described above according to the instructions stored by the memory.
The invention further provides a readable storage medium having stored therein machine readable instructions which, when executed by a machine, perform a method of determining a trigger time of an event in a power system according to any of the preceding claims.
According to the invention, the triggering time of the event is determined by the method of envelope comparison, so that quick positioning can be realized. In addition, in the process of acquiring the envelope curve, the harmonic waves are considered, so that the interference of the harmonic waves can be restrained, and the final determination result is more accurate.
Drawings
The above and other features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing in detail preferred embodiments thereof with reference to the attached drawings in which:
fig. 1A is a flowchart illustrating a method for determining a trigger time of an event in a power system according to an embodiment of the present invention.
Fig. 1B is a schematic diagram of waveforms of voltages without taking harmonic factors into consideration.
Fig. 2 is a flowchart of a method for determining a trigger time of an event in a power system according to another embodiment of the present invention.
Fig. 3A is a schematic diagram of an actual waveform, an upper limit envelope and a lower limit envelope according to an embodiment of the present invention.
Fig. 3B is a schematic diagram of an actual waveform, an upper limit envelope and a lower limit envelope according to another embodiment of the present invention.
Fig. 3C is a schematic diagram of an actual waveform, an upper limit envelope and a lower limit envelope according to another embodiment of the present invention.
Fig. 3D is a schematic diagram of an actual waveform, an upper limit envelope, and a lower limit envelope according to another embodiment of the present invention.
Fig. 4A is a schematic structural diagram of an apparatus for determining a trigger time of an event in a power system according to an embodiment of the present invention.
Fig. 4B is a schematic structural diagram of an apparatus for determining a trigger time of an event in a power system according to another embodiment of the present invention.
Detailed Description
The present invention will be further described in detail with reference to the following examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. Nouns and pronouns for humans in this patent application are not limited to a particular gender.
Example 1
The embodiment provides a method for determining a trigger time of an event in a power system, and an execution subject of the method is a device for determining the trigger time of the event in the power system, and the device can be integrated in a power quality device.
Fig. 1A is a flowchart of a method for determining a trigger time of an event in a power system according to the present embodiment. The method comprises the following steps:
step 101, if it is identified that an event occurs, a sampling value of an electrical parameter of the electrical power system in the first M periods of the initial trigger time of the event is obtained, where the electrical parameter is one of a current or a voltage, and one period is equal to one cycle of the electrical parameter.
For an electrical power system, it is an alternating current, so the waveform of the electrical parameter is a sine wave or a cosine wave, where the electrical parameter is a current or a voltage.
The event here may be a fault event, specifically a jump of the fundamental phase angle, a sudden change of the voltage amplitude, and more specifically an event capable of triggering a fault log. How to identify whether an event occurs belongs to the prior art, for example, whether an event occurs is determined in real time by adopting an RMS (Root mean Square value), and of course, the event can also be determined according to factors such as the variation amplitude of voltage and the variation amplitude of current, which are not described in detail.
After determining that the event occurs, a start time of the event is correspondingly determined, and at this time, the determined start time is an initial trigger time, and whether the initial trigger time needs to be adjusted is determined so as to be more consistent with a real trigger time of the event, and the trigger time after adjustment is a final trigger time in the following.
For example, as shown in fig. 1B, a schematic diagram of a waveform of a voltage is shown. The length of each monitoring window is a cycle, such as the p-th monitoring window, where the monitoring window is used for calculating a calculation window used when an event occurs, specifically, all electrical parameters in the monitoring window are used to determine whether the event occurs, for example, when the disturbance event is detected according to the detection method recommended by IEC61000-4-30, the electrical parameters in the whole cycle are needed to determine whether the disturbance event occurs. As an exemplary illustration, the present embodiment may determine whether a disturbance event occurs according to an RMS (Root mean Square) value of a voltage of a monitoring window, and when it is recognized that the disturbance event occurs, a start time of the monitoring window is a trigger time of the disturbance event, that is, an initial trigger time. In the prior art, there are many other methods for determining the trigger time of an event, which are not described herein.
Assuming that the trigger time of the event is the start time of the p-th monitoring window, under the condition that M is 1, acquiring a sampling value of voltage in the cycle before the p-th monitoring window, namely, a sampling value of voltage in the cycle from the point A to the point B; in the case where M is 1.5, it is necessary to acquire a sampling value of the voltage in the first 1.5 cycles of the p-th monitoring window, that is, a sampling value of the voltage in the cycle from point C to point B.
In this embodiment, the value of M may be determined according to the actual situation. For example, in the event that an event is identified, the current fundamental phase angle of the electrical parameter is determined. If the current fundamental phase angle is between-180 DEG and 0 DEG, M is 1.5; if the current fundamental phase angle is between 0 ° and 180 °, then M is 1. For example, if it is identified that an event occurs through the electrical parameters of the p-th monitoring window, the current fundamental wave phase angle is determined according to the electrical parameters of the first Q cycles of the p-th monitoring window, where Q is, for example, 10, if it is determined that the current fundamental wave phase angle is between-180 ° and 0 °, it is indicated that the delay of the initial trigger time of the determined event compared with the actual trigger time of the event is greater than half a cycle, and it is necessary to shift the additional half cycle forward, so that capturing the waveform distortion point, that is, the actual trigger time of the event is more beneficial, so that M is 1.5, that is, it is necessary to acquire the electrical parameters in 1.5 cycles before the initial trigger time; if the current fundamental wave phase angle is determined to be between 0 and 180 degrees, the delay of the initial trigger time of the judged event compared with the actual trigger time of the event is smaller than half a cycle, so that only one cycle is required to be shifted forwards, and M is 1.
Step 102, determining the actual waveform of the electrical parameter in the first M periods according to the acquired sampling value of the electrical parameter.
The corresponding actual waveform can be obtained from the sampled value of the electrical parameter, for example, the actual waveform of the voltage is obtained from the sampled value of the voltage, and the actual waveform of the current is obtained from the sampled value of the current.
Step 103, determining an upper limit envelope and a lower limit envelope of the electrical parameter in the first M periods, wherein the upper limit envelope and the lower limit envelope are determined based on fundamental waves and harmonic waves of the electrical parameter.
The upper and lower envelopes of the electrical parameter are predicted from sampled values of the electrical parameter prior to the first M cycles. For example, the upper limit envelope and the lower limit envelope of the electrical parameter of the subsequent 10 cycles are determined using the sampled values of the electrical parameter of the 10 cycles, the period of determining the envelope may be determined according to actual needs, for example, the upper limit envelope and the lower limit envelope of the electrical parameter of the subsequent 10 cycles are determined every 1 cycle, so that the upper limit envelope and the lower limit envelope may be updated in real time. As shown in fig. 1A, assuming that m=1, the upper limit envelope and the lower limit envelope of the electrical parameter in the p-1 th monitoring window are determined, and in particular, the upper limit envelope and the lower limit envelope of the electrical parameter in the p-1 st monitoring window to the p-8 th monitoring window may be determined by using the electrical parameters of the p-11 th monitoring window to the p-2 th monitoring window.
In the present embodiment, the influence of harmonics is taken into consideration in determining both the upper limit envelope and the lower limit envelope. As an exemplary illustration, the steps specifically include:
the upper and lower envelopes of the electrical parameters for the first M cycles are determined according to the following formula:
upper envelope = Ref (t) +delta,
lower envelope = Ref (t) -delta,
wherein F is 0 Is the effective value of the fundamental wave of the electrical parameter, f is the frequency of the power system, t is the sampling time, H n Is the effective value of the N-order harmonic of the electrical parameter, N is the highest harmonic that can be detected,the phase angle of the zero crossing point of the fundamental wave corresponding to the n-order harmonic wave is shown, and delta is a preset threshold value. Where N is the highest harmonic that can be detected by the power quality device, which is related to the nature of the power quality device itself and will not be described in detail herein. Delta is, for example, a percentage of a reference value of an electrical parameter, for example, 15% of a reference value of a voltage, and may be specifically selected according to actual needs.
Wherein the fundamental wave isHarmonic wave of->In this way, the effects of harmonics can be avoided.
Step 102 and step 103 may be performed simultaneously, or may be performed sequentially, and step 103 may be performed before step 102, or may be performed after step 102, which is not limited in order.
And 104, determining the final trigger time of the event according to the actual waveform, the upper limit envelope curve and the lower limit envelope curve.
As an exemplary illustration, it is determined whether the actual waveform exceeds the ranges of the upper limit envelope and the lower limit envelope, and if so, the starting time of the actual waveform exceeding the ranges of the upper limit envelope and the lower limit envelope is updated as the final trigger time of the event. If it is determined from the actual waveform that it exceeds the upper or lower envelope at a certain time, the time is the final trigger time of the event. In this way, in the scene of the trigger time of the event, for example, fault recording, the whole recording corresponding to the fault can be obtained more completely.
According to the embodiment, the triggering time of the event is determined by the method of envelope comparison, so that quick positioning can be realized. In addition, in the process of acquiring the envelope curve, the harmonic waves are considered, so that the interference of the harmonic waves can be restrained, and the final determination result is more accurate.
Example two
The embodiment specifically supplements the method for determining the trigger time of the event in the power system according to the first embodiment.
Fig. 2 is a flowchart of a method for determining a trigger time of an event in a power system according to the present embodiment. The method for determining the triggering time of the event in the power system comprises the following steps:
step 200, if it is identified that an event occurs, determining a current fundamental phase angle of the electrical parameter.
If the current fundamental phase angle is between-180 DEG and 0 DEG, M is 1.5;
if the current fundamental phase angle is between 0 ° and 180 °, then M is 1.
Specifically, the current fundamental phase angle of the electrical parameter can be determined according to the electrical parameter of the first Q cycles of the trigger time of the event initiation.
Step 201, obtaining sampling values of electrical parameters of the electrical system in the first M periods of the initial trigger time of the event, wherein the electrical parameters are one of current or voltage, and one period is equal to one cycle of the electrical parameters.
The identification of whether an event has occurred may be performed in any manner known in the art, such as by the RMS value of the voltage, and is not described in detail.
This step corresponds to step 101 and is not described here.
Step 202, determining the actual waveform of the electrical parameter in the first M periods according to the acquired sampling value of the electrical parameter.
This step corresponds to step 102 and is not described in detail herein.
Step 203, determining an upper limit envelope and a lower limit envelope of the electrical parameter of the first M cycles according to the following formula:
upper envelope = Ref (t) +delta,
lower envelope = Ref (t) -delta,
wherein F is 0 Is the effective value of the fundamental wave of the electrical parameter, f is the frequency of the power system, t is the sampling time, H n Is the effective value of the N-order harmonic of the electrical parameter, N is the highest harmonic that can be detected,the phase angle of the zero crossing point of the fundamental wave corresponding to the n-order harmonic wave is shown, and delta is a preset threshold value.
This step is identical to step 103 and will not be described in detail herein.
Step 204, determining whether the actual waveform exceeds the range of the upper limit envelope and the lower limit envelope, if yes, executing step 205, otherwise executing step 206.
If there is a portion of the actual waveform that exceeds the upper limit envelope or exceeds the lower limit envelope, it may be determined whether the actual waveform exceeds the ranges of the upper limit envelope and the lower limit envelope.
Step 205, updating the starting time when the actual waveform exceeds the range of the upper limit envelope curve and the lower limit envelope curve to the final trigger time of the event.
Step 206, taking the original trigger time as the final trigger time of the event.
And then, the final trigger time can be adopted to supplement the fault record data corresponding to the event so as to enable the fault record data to be more complete.
Therefore, more accurate event triggering time can be provided for the user, and user experience is improved.
Example III
The embodiment further supplements the foregoing method for determining the trigger time of the event in the power system by using a specific example. In this embodiment, the electrical parameter is voltage, and the length of the monitoring window is equal to one full cycle.
Example one
As shown in fig. 3A, the actual waveform S, the upper limit envelope U and the lower limit envelope L are shown, the abscissa thereof is the sampling time, the unit is seconds (S), and the ordinate thereof is the ratio of the actual value of the voltage to the rated value of the voltage, which is the nominal value of the voltage of the power system. Assuming that a fault occurs according to the RMS value of the voltage in the p-th monitoring window, the initial trigger time of the event is the start time F of the p-th monitoring window, and the actual waveform, upper limit envelope and lower limit envelope of the p-th monitoring window are also shown in fig. 3A. In this embodiment, if Q is 10, the current fundamental phase angle is determined according to the voltage sampling value of the first 10 cycles of the nth monitoring window. Assuming that the current fundamental phase angle is 0 ° to 180 °, then M is 1.
And then, acquiring an actual waveform corresponding to the first 1 voltage cycle of the nth monitoring window, and acquiring an upper limit envelope curve and a lower limit envelope curve corresponding to the first 1 voltage cycle of the nth monitoring window. And comparing to determine that the actual waveform S exceeds the range of the upper limit envelope curve U and the lower limit envelope curve L at the moment E, and taking the moment E as the final trigger moment.
Fig. 3B shows a case where the actual waveform S in the first M periods does not exceed the ranges of the upper limit envelope U and the lower limit envelope L. At this time, the initial trigger time of the event is the final trigger time of the event.
Example two
As shown in fig. 3C, which shows a case where the voltage value exceeds 20% of the nominal voltage, the abscissa is time, the unit is seconds(s), and the ordinate is the ratio of the actual value of the voltage to the rated value of the voltage, which is the nominal value of the voltage of the power system. When an event is detected by adopting a transient wave mode, the position of the voltage amplitude change, namely the P1 position is the trigger time of the event and the P2 position is the termination time of the event can be rapidly determined by adopting the envelope comparison method.
Example three
As shown in fig. 3D, which shows the case of a fundamental phase jump, the abscissa is time, the unit is seconds(s), and the ordinate is the ratio of the actual value of the voltage to the nominal value of the voltage, which is the nominal value of the voltage of the power system. Under the condition that an event is detected by adopting a transient wave mode, the position of the voltage fundamental wave phase jump change, namely the P3 moment is the triggering moment of the fundamental wave phase jump, and the P4 position is the ending moment of the fundamental wave phase jump, can be rapidly determined by adopting the envelope comparison method.
From the above examples, it can be seen that by considering the envelope comparison method of harmonics, the trigger time of an event can be found quickly and accurately.
Example IV
The present embodiment provides a device for determining the trigger moment of an event in an electrical power system, which may be integrated in a power quality device.
As shown in fig. 4A, a schematic structural diagram of an apparatus for determining a trigger time of an event in a power system according to the present embodiment is shown. The means for determining the trigger moment of an event in the power system may be integrated in the power quality device comprising a first acquisition unit 401, a first determination unit 402, a second determination unit 403 and a third determination unit 404.
The first obtaining unit 401 is configured to obtain, if it is identified that an event occurs, a sampling value of an electrical parameter of the electrical system in the first M periods of the trigger time of the initial event, where the electrical parameter is one of a current or a voltage, and one period is equal to one cycle of the electrical parameter; the first determining unit 402 is configured to determine an actual waveform of the electrical parameter in the first M periods according to the acquired sampling value of the electrical parameter; the second determining unit 403 is configured to determine an upper limit envelope and a lower limit envelope of the electrical parameter in the first M periods, each of the upper limit envelope and the lower limit envelope being determined based on a fundamental wave and a harmonic wave of the electrical parameter; the third determining unit 404 is configured to determine a final trigger time of the event according to the actual waveform, the upper limit envelope, and the lower limit envelope.
Alternatively, the second determining unit 403 is configured to:
the upper and lower envelopes of the electrical parameters for the first M cycles are determined according to the following formula:
upper envelope = Ref (t) +delta,
lower envelope = Ref (t) -delta,
wherein F is 0 Is the effective value of the fundamental wave of the electrical parameter, f is the frequency of the power system, t is the sampling time, H n Is the effective value of the N-order harmonic of the electrical parameter, N is the highest harmonic that can be detected,fundamental wave crossing corresponding to n-order harmonic waveThe phase angle of the zero point, delta, is a preset threshold.
Optionally, as shown in fig. 4B, the present embodiment further includes a fourth determining unit 405, where the fourth determining unit 405 is configured to:
determining the current fundamental phase angle of the electrical parameter;
if the current fundamental phase angle is between-180 DEG and 0 DEG, M is 1.5;
if the current fundamental phase angle is between 0 ° and 180 °, then M is 1.
Alternatively, the fourth determining unit 405 is specifically configured to: and determining the current fundamental wave phase angle of the electrical parameters according to the electrical parameters of the first Q periods of the initial trigger time of the event.
Optionally, the third determining unit 404 is specifically configured to:
judging whether the actual waveform exceeds the range of the upper limit envelope curve and the lower limit envelope curve;
if the judgment results are yes, updating the initial time when the actual waveform exceeds the range of the upper limit envelope curve and the lower limit envelope curve to be the final trigger time of the event.
Optionally, as shown in fig. 4B, the present embodiment further includes a second acquiring unit 406, where the second acquiring unit 406 is configured to acquire, according to the final trigger time, the fault record data corresponding to the event.
The working method of each unit of this embodiment is the same as that of the previous embodiment, and will not be described here again.
According to the embodiment, the triggering time of the event is determined by the method of envelope comparison, so that quick positioning can be realized. In addition, in the process of acquiring the envelope curve, the harmonic waves are considered, so that the interference of the harmonic waves can be restrained, and the final determination result is more accurate.
The invention also provides a device for determining the triggering time of an event in a power system, which comprises at least one memory and at least one processor. The memory is used for storing instructions. The processor is configured to perform the method of determining the trigger time of an event in a power system described in any of the foregoing embodiments according to instructions stored in the memory.
Embodiments of the present invention also provide a readable storage medium. The readable storage medium has stored therein machine readable instructions which, when executed by a machine, perform the method of determining the trigger time of an event in a power system described in any of the previous embodiments.
The readable medium has stored thereon machine readable instructions which, when executed by a processor, cause the processor to perform any of the methods described above. In particular, a system or apparatus may be provided with a readable storage medium having stored thereon software program code implementing the functions of any of the above embodiments, and having a computer or processor of the system or apparatus read out and execute machine readable instructions stored in the readable storage medium.
In this case, the program code itself read from the readable medium may implement the functions of any of the above-described embodiments, and thus the machine-readable code and the readable storage medium storing the machine-readable code form part of the present invention.
Examples of readable storage media include floppy disks, hard disks, magneto-optical disks, optical disks (e.g., CD-ROMs, CD-R, CD-RWs, DVD-ROMs, DVD-RAMs, DVD-RWs, DVD+RWs), magnetic tapes, nonvolatile memory cards, and ROMs. Alternatively, the program code may be downloaded from a server computer or cloud by a communications network.
It will be appreciated by those skilled in the art that various changes and modifications can be made to the embodiments disclosed above without departing from the spirit of the invention. Accordingly, the scope of the invention should be limited only by the attached claims.
It should be noted that not all the steps and units in the above flowcharts and the system configuration diagrams are necessary, and some steps or units may be omitted according to actual needs. The execution sequence of the steps is not fixed and can be adjusted as required. The apparatus structures described in the above embodiments may be physical structures or logical structures, that is, some units may be implemented by the same physical entity, or some units may be implemented by multiple physical entities, or may be implemented jointly by some components in multiple independent devices.
In the above embodiments, the hardware unit may be mechanically or electrically implemented. For example, a hardware unit or processor may include permanently dedicated circuitry or logic (e.g., a dedicated processor, FPGA, or ASIC) to perform the corresponding operations. The hardware unit or processor may also include programmable logic or circuitry (e.g., a general purpose processor or other programmable processor) that may be temporarily configured by software to perform the corresponding operations. The particular implementation (mechanical, or dedicated permanent, or temporarily set) may be determined based on cost and time considerations.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.
Claims (11)
1. A method of determining a trigger time for an event in an electrical power system, comprising:
if the occurrence of an event is identified, acquiring sampling values of electrical parameters of the power system in the first M periods of the initial trigger time of the event, wherein the electrical parameters are one of current or voltage, and one period is equal to one cycle of the electrical parameters;
determining an actual waveform of the electrical parameter in the first M periods according to the acquired sampling value of the electrical parameter;
determining an upper limit envelope and a lower limit envelope of the electrical parameter over the first M cycles, the upper limit envelope and the lower limit envelope each determined based on fundamental waves and harmonics of the electrical parameter;
and determining the final trigger time of the event according to the actual waveform, the upper limit envelope curve and the lower limit envelope curve.
2. The determination method according to claim 1, wherein determining an upper limit envelope and a lower limit envelope of the electrical parameter in the first M periods includes:
determining an upper and lower envelope of the electrical parameter for the first M cycles according to the following formula:
upper envelope = Ref (t) +delta,
lower envelope = Ref (t) -delta,
wherein F is 0 Is the effective value of the fundamental wave of the electrical parameter, f is the frequency of the power system, t is the sampling time, H n Is the effective value of the N-order harmonic of the electrical parameter, N is the highest harmonic that can be detected,the phase angle of the zero crossing point of the fundamental wave corresponding to the n-order harmonic wave is shown, and delta is a preset threshold value.
3. The method of determining according to claim 1, wherein determining the final trigger time of the event from the actual waveform, the upper limit envelope, and the lower limit envelope comprises:
judging whether the actual waveform exceeds the range of the upper limit envelope curve and the lower limit envelope curve;
if the judging results are yes, updating the initial time when the actual waveform exceeds the range of the upper limit envelope curve and the lower limit envelope curve to the final trigger time of the event.
4. The determination method according to claim 1, characterized by further comprising, before acquiring the sampled values of the electrical parameter of the electrical power system in the first M cycles of the trigger time of the event initiation:
determining the current fundamental wave phase angle of the electrical parameter;
if the current fundamental wave phase angle is between-180 DEG and 0 DEG, the M is 1.5;
if the current fundamental phase angle is between 0 ° and 180 °, then M is 1.
5. The method of determining of claim 4, wherein determining the current fundamental phase angle of the electrical parameter comprises:
and determining the current fundamental wave phase angle of the electrical parameter according to the electrical parameter of the first Q periods of the initial trigger time of the event.
6. The determining method according to any one of claims 1 to 5, characterized by further comprising, after determining a final trigger time of the event from the actual waveform, the upper limit envelope, and the lower limit envelope:
and acquiring fault wave recording data corresponding to the event according to the final trigger time.
7. An apparatus for determining a trigger time for an event in an electrical power system, comprising:
the first acquisition unit is used for acquiring sampling values of electrical parameters of the power system in the first M periods of the initial trigger time of the event if the event is identified, wherein the electrical parameters are one of current and voltage, and one period is equal to one cycle of the electrical parameters;
a first determining unit, configured to determine an actual waveform of the electrical parameter in the first M periods according to the acquired sampling value of the electrical parameter;
a second determining unit configured to determine an upper limit envelope and a lower limit envelope of the electrical parameter in the first M periods, each of the upper limit envelope and the lower limit envelope being determined based on fundamental waves and harmonics of the electrical parameter;
and the third determining unit is used for determining the final trigger time of the event according to the actual waveform, the upper limit envelope curve and the lower limit envelope curve.
8. The apparatus of claim 7, wherein the second determining unit is configured to:
determining an upper and lower envelope of the electrical parameter for the first M cycles according to the following formula:
upper envelope = Ref (t) +delta,
lower envelope = Ref (t) -delta,
wherein F is 0 Is the effective value of the fundamental wave of the electrical parameter, f is the frequency of the power system, t is the sampling time, H n Is the effective value of the N-order harmonic of the electrical parameter, N is the highest harmonic that can be detected,the phase angle of the zero crossing point of the fundamental wave corresponding to the n-order harmonic wave is shown, and delta is a preset threshold value.
9. The apparatus of claim 7, further comprising a fourth determination unit to:
determining the current fundamental wave phase angle of the electrical parameter;
if the current fundamental wave phase angle is between-180 DEG and 0 DEG, the M is 1.5;
if the current fundamental phase angle is between 0 ° and 180 °, then M is 1.
10. An apparatus for determining a trigger time for an event in an electrical power system, comprising:
at least one memory for storing instructions;
at least one processor for performing the method of determining the trigger moment of an event in a power system according to any one of claims 1-6 according to the instructions stored by the memory.
11. A readable storage medium having stored therein machine readable instructions which, when executed by a machine, perform the method of determining a trigger time of an event in a power system according to any of claims 1-6.
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| CN202311768736.9A CN117833221A (en) | 2023-12-21 | 2023-12-21 | Method and device for determining triggering time of event in power system |
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| CN202311768736.9A CN117833221A (en) | 2023-12-21 | 2023-12-21 | Method and device for determining triggering time of event in power system |
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