CN108627795B - Method and device for monitoring open circuit of voltage transformer in measuring circuit of power equipment - Google Patents
Method and device for monitoring open circuit of voltage transformer in measuring circuit of power equipment Download PDFInfo
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- CN108627795B CN108627795B CN201810691267.8A CN201810691267A CN108627795B CN 108627795 B CN108627795 B CN 108627795B CN 201810691267 A CN201810691267 A CN 201810691267A CN 108627795 B CN108627795 B CN 108627795B
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- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G01R35/02—Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating
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Abstract
When the voltage transformers in the measuring circuit of the power equipment are monitored to be broken, voltage signal values of each phase output by two groups of same voltage transformers which are connected in parallel with each other on an output line of the power equipment and located in the measuring circuit of the power equipment are collected, and if the absolute value of the difference value between the voltage signal values of the same phase is judged to exceed a preset threshold value, one of the two groups of voltage transformers is determined to be broken. In the embodiment of the invention, in the process of monitoring the open circuit of the voltage transformer in the measuring circuit of the power equipment, the current signal of the current transformer applied to the output line of the power equipment is not needed, and the acquisition and calculation complexity is reduced, so that the open circuit of the voltage transformer in the measuring circuit of the power equipment is monitored quickly and reliably.
Description
Technical Field
The invention relates to the technical field of power systems, in particular to a method and a device for monitoring the open circuit of a voltage transformer in a measuring circuit of power equipment.
Background
In order to ensure the normal operation of the power equipment such as a generator or a transformer, a measuring circuit is provided for the power equipment, and the operation state of the power equipment is monitored online. Fig. 1 is a schematic diagram of a measurement circuit structure of a power device in the prior art, which illustrates a single-phase output current-voltage line of the power device being monitored, wherein G is the power device, a current transformer 101 is connected in series and a voltage transformer 102 is connected in parallel to the output current-voltage line of G, so as to respectively reduce the collected voltage and current, and output the reduced voltage signal and current signal to a protection function unit 103. The protection function unit 103 monitors the operation state of the power equipment according to the voltage signal and the current signal, and performs corresponding relay protection and automatic control on the power equipment according to the monitored operation state of the power equipment. For the three-phase output current and voltage circuit of the power equipment, the monitoring process is similar to the unit output current and voltage circuit, and only three voltage transformers 102 need to be connected in parallel on the three-phase output current and voltage circuit respectively, and three current transformers 101 need to be connected in series on the three-phase output current and voltage circuit respectively, so that three-phase voltage and current are acquired, an electric signal and a current signal are obtained after voltage reduction and current reduction, and the electric signal and the current signal are output to the protection function unit 103 for monitoring.
During the monitoring of the power equipment using the measurement circuit shown in fig. 1, the voltage transformer 102 may be disconnected. The reason for this is that the fuses in series with the voltage transformer 102 are blown, the fuses are typically connected in series on the primary or secondary line of the voltage transformer 102, and the blown fuses may be blown on the primary line or blown on the secondary line. Once the voltage transformer 102 is disconnected, the voltage signal from the defective voltage transformer 102 cannot reflect the real operating state of the power equipment, which may cause the protection function unit 103 in the measurement circuit to misjudge the operating state of the power equipment, and erroneously control the power equipment to trip to protect the power equipment, which may result in loss of operating resources of the power equipment.
In order to overcome the above problem, the open circuit of the voltage transformer 102 in the measuring circuit is monitored, and the protection function unit 103 in the measuring circuit is locked according to the monitoring result, so that the voltage transformer 102 is determined to be open circuit, and the power equipment is not controlled to be tripped by mistake. Specifically, fig. 2 is a schematic diagram of a prior art measurement circuit with a function of monitoring disconnection of the voltage transformer 102. As shown in fig. 2, a monitoring and calculating unit 201 is further provided in the measuring circuit, and receives the voltage signal after voltage reduction by the voltage transformer 102 and the current signal after current reduction by the current transformer 101, and calculates whether the voltage transformer 102 is open-circuited according to the signals: if the voltage signal and the current signal are received by the protection function unit 103, the power equipment is not judged to have a fault according to the result, and the tripping of the power equipment is controlled by mistake.
Here, the basis for the judgment of whether the voltage transformer 102 is open-circuited by the monitoring calculation unit 201 is obtained based on the received voltage signal and current signal. Specifically, when the voltage transformer 102 on one-phase line or two-phase line on the three-phase voltage current line output by the power equipment is open-circuited, the judgment basis is that the current signal is balanced and the voltage signal is unbalanced, and the judgment basis of the voltage signal unbalance is determined according to the ratio between the positive sequence voltage signal and the negative sequence voltage signal; when the voltage transformers 102 on the three-phase voltage and current lines output by the power equipment are all in an open circuit state, the collected three-phase voltage signals are all jumped to a low value under the condition that the current signals are judged not to jump.
The method for monitoring whether the mutual inductor in the measuring circuit is broken or not has the following defects:
the monitoring and calculating unit 201 needs to calculate according to a large amount of data including voltage signals and current signals, which requires about 1 measurement cycle, so that, because the calculation amount of the monitoring and calculating unit 201 is large, the current signals and the voltage signals of the transformer 102 are collected from the monitoring and calculating unit, the open circuit of the transformer 102 is determined through calculation, and then the time required for the locking protection function unit 103 is 20 milliseconds, which takes a long time.
Therefore, how to quickly monitor the open circuit of the voltage transformer in the measuring circuit of the power equipment is an urgent problem to be solved.
Disclosure of Invention
In view of the above, the present invention provides a method for monitoring disconnection of a voltage transformer in a measurement circuit of an electrical device, which quickly monitors disconnection of a voltage transformer in a measurement circuit of an electrical device.
The embodiment of the invention provides a device for monitoring the disconnection of a voltage transformer in a measuring circuit of power equipment.
The invention is realized by the following steps:
a method of monitoring a voltage transformer open circuit in a measurement circuit of an electrical device, an output line of the electrical device connecting two identical sets of voltage transformers, the two sets of voltage transformers being connected in parallel to each other and located in the measurement circuit of the electrical device, comprising: acquiring voltage signal values of each phase output by the two groups of voltage transformers; and if the absolute value of the difference value between the voltage signal values with the same phase exceeds a preset threshold value, determining that one of the two groups of voltage transformers is broken. The method does not relate to the signal value acquisition and calculation of a current transformer in the measuring circuit in the monitoring process, saves the time cost, and quickly realizes the monitoring of the open circuit of the voltage transformer in the measuring circuit of the power equipment.
The step of obtaining the corresponding voltage signal values output by the two groups of voltage transformers comprises the following steps: continuously acquiring voltage signal values of each phase output by the two groups of voltage transformers; if the absolute value of the difference value between the voltage signal values with the same phase exceeds a preset threshold value, the step of breaking one of the two groups of voltage transformers comprises the following steps: and if the times that the absolute value of the difference value of the voltage signal values with the same phase exceeds the preset threshold value is continuously judged to be larger than or equal to the preset times value, determining that one of the two groups of voltage transformers is broken. The judgment and comparison of a plurality of monitoring periods are adopted in the monitoring process, and when the judgment and comparison are the same, which one of the two groups of voltage transformers is broken is determined, so that the judgment is more accurate.
The preset threshold value is 8% of the rated voltage of the voltage transformer. Therefore, the preset threshold is set to be not 0 and is set according to the empirical value, so that the voltage signal values of the corresponding phases of the different voltage transformers are prevented from being acquired, and the open circuit misjudgment is avoided due to the inevitable difference caused by unstable voltage of the output line of the power equipment.
The power device is a three-phase four-wire output type device, the method further comprising: and comparing the two in-phase voltage signal values, and determining that the group of voltage transformers with smaller voltage signal values are voltage transformers with broken circuits, and the corresponding phase is the phase with the broken circuit. In this way it is possible to further determine exactly which phase of which of the two sets of said voltage transformers has been open-circuited.
The power device is a three-phase three-wire output type power device, the voltage signal value is a difference value of a line voltage between each two phases of the voltage transformer, and the method further comprises: and if the absolute value of the difference value between the two groups of voltage signal values in the same phase exceeds a preset threshold value, determining that one phase circuit shared by the two groups of voltage signal values in the same phase is broken.
After determining that one of the two groups of voltage transformers is disconnected, the method further comprises the following steps: and sending a blocking signal to a protection function unit in the measuring circuit, wherein the protection function unit is used for protecting the power equipment. Therefore, the protection function unit can be locked so that the protection function unit is not erroneously controlled to the electric power equipment.
An apparatus for monitoring the disconnection of voltage transformers in a measuring circuit of an electrical installation, the output line of which connects two identical sets of voltage transformers, which are connected in parallel to each other and included in the measuring circuit of the electrical installation, the apparatus comprising:
the receiving module is used for acquiring voltage signal values of each phase output by the two groups of voltage transformers; and the judging module is used for determining that one of the two groups of voltage transformers is broken if the absolute value of the difference value between the voltage signal values with the same phase exceeds a preset threshold value. Therefore, signal value collection and calculation of a current transformer in the measuring circuit are not involved in the monitoring process, time cost is saved, and disconnection of a voltage transformer in the measuring circuit of the power equipment is rapidly monitored.
The receiving module is specifically configured to: continuously acquiring voltage signal values of each phase output by the two groups of voltage transformers; the determination module is specifically configured to: and if the times that the absolute value of the difference value of the voltage signal values with the same phase exceeds the preset threshold value is continuously judged to be larger than or equal to the preset times value, determining that one of the two groups of voltage transformers is broken. Therefore, judgment and comparison of a plurality of monitoring periods are adopted in the monitoring process, and when the judgment and comparison are the same, which one of the two groups of voltage transformers is broken is determined, so that the judgment is more accurate.
The power device is a three-phase four-wire output type power device, and the determination module is further configured to: comparing the magnitude of the two in-phase voltage signal values, and determining that a group of voltage transformers with smaller voltage signal values are voltage transformers with broken circuits, and the corresponding phase is the phase with the broken circuit; in this way it is possible to further determine exactly which phase of which of the two sets of said voltage transformers has been open-circuited.
Or the power equipment is of a three-phase three-wire output type, and the voltage signal value is the difference value of line voltages between every two phases of the voltage transformer; the determination module is further configured to: and if the absolute value of the difference value between the two groups of voltage signal values in the same phase exceeds a preset threshold value, determining that one phase circuit shared by the two groups of voltage signal values in the same phase is broken. In this way it is possible to further determine exactly which phase of the two sets of said voltage transformers has been disconnected.
And the sending module is used for sending a blocking signal to a protection function unit in the measuring circuit, and the protection function unit is used for protecting the power equipment. Therefore, the protection function unit can be locked so that the protection function unit is not erroneously controlled to the electric power equipment.
The device for monitoring the open circuit of the voltage transformer in the measuring circuit of the power equipment, wherein the output line of the power equipment is connected with two groups of same voltage transformers, the two groups of voltage transformers are mutually connected in parallel and are included in the measuring circuit of the power equipment, and the device comprises: at least one communication interface for communicating with two sets of said voltage transformers; at least one memory for storing voltage signal values; at least one processor, which is connected to the communication interface and the memory, and acquires the voltage signal values of each phase output by the two sets of voltage transformers through the communication interface and stores the voltage signal values in the memory, wherein the processor is used for executing the method for monitoring the open circuit of the voltage transformers in the measuring circuit of the power equipment. Therefore, signal value collection and calculation of a current transformer in the measuring circuit are not involved in the monitoring process, time cost is saved, and disconnection of a voltage transformer in the measuring circuit of the power equipment is rapidly monitored.
The device for monitoring the open circuit of the voltage transformer in the measuring circuit of the power equipment, wherein the output line of the power equipment is connected with two groups of same voltage transformers, the two groups of voltage transformers are mutually connected in parallel and are included in the measuring circuit of the power equipment, and the device is characterized by comprising: at least one memory for storing instructions; at least one processor configured to perform any of the above methods of monitoring disconnection of a voltage transformer in a measurement circuit of an electrical power device according to instructions stored in the memory. Therefore, signal value collection and calculation of a current transformer in the measuring circuit are not involved in the monitoring process, time cost is saved, and disconnection of a voltage transformer in the measuring circuit of the power equipment is rapidly monitored.
Readable storage media having stored therein machine readable instructions which, when executed by a machine, perform a method of monitoring for a voltage transformer discontinuity in a measurement circuit of an electrical power device according to any of the preceding claims. Therefore, signal value collection and calculation of a current transformer in the measuring circuit are not involved in the monitoring process, time cost is saved, and disconnection of a voltage transformer in the measuring circuit of the power equipment is rapidly monitored.
It can be seen from the above solutions that, in the embodiments of the present invention, when a voltage transformer in a measurement circuit of a power device is monitored to be open-circuited, voltage signal values of each phase output by two groups of identical voltage transformers that are connected in parallel to each other on an output line of the power device and located in the measurement circuit of the power device are collected, and if it is determined that an absolute value of a difference between voltage signal values of the same phase exceeds a preset threshold, it is determined that one of the two groups of voltage transformers is open-circuited. Furthermore, according to the judgment result, which one of the two groups of voltage transformers is disconnected can be determined. In the embodiment of the invention, in the process of monitoring the open circuit of the voltage transformer in the measuring circuit of the power equipment, the current signal of the current transformer applied to the output line of the power equipment is not needed, and the acquisition and calculation complexity is reduced, so that the open circuit of the voltage transformer in the measuring circuit of the power equipment is monitored quickly and reliably.
Drawings
The foregoing and other features and advantages of the invention will become more apparent to those skilled in the art to which the invention relates upon consideration of the following detailed description of a preferred embodiment of the invention with reference to the accompanying drawings, in which:
fig. 1 is a schematic diagram of a measurement circuit structure of an electrical device provided in the prior art;
fig. 2 is a schematic diagram of a measurement circuit provided in the prior art and having a function of monitoring disconnection of the voltage transformer 102;
fig. 3 is a flowchart of a method for monitoring disconnection of a voltage transformer in a measurement circuit of an electrical device according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of an apparatus for monitoring disconnection of a voltage transformer in a measurement circuit of an electrical device according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a system for monitoring disconnection of a voltage transformer in a measurement circuit of an electrical device according to an embodiment of the present invention.
Reference numerals
G-power equipment
101-current transformer
102-Voltage transformer
103-protection function unit
201-monitoring a computing Unit
401-receiving module
402-decision Module
501-monitoring voltage calculating unit
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail by referring to the following examples.
In order to quickly and reliably monitor the open circuit of the voltage transformers in the measuring circuit of the power equipment, when the open circuit of the voltage transformers in the measuring circuit of the power equipment is monitored, voltage signal values of each phase output by two groups of same voltage transformers which are connected in parallel with each other on an output line of the power equipment and located in the measuring circuit of the power equipment are collected, and if the absolute value of the difference value between the voltage signal values of the same phase is judged to exceed a preset threshold value, one of the two groups of voltage transformers is determined to be open circuit. Furthermore, according to the judgment result, which voltage transformer of the two groups of voltage transformers or which phase line is broken can be determined according to the line condition. In the embodiment of the invention, in the process of monitoring the open circuit of the voltage transformer in the measuring circuit of the power equipment, the current signal of the current transformer applied to the output line of the power equipment is not needed, and the acquisition and calculation complexity is reduced.
In an electric power system, for many electric power devices, such as generators and transformers, usually, more than two sets of voltage transformers are connected in parallel to a voltage current line (output line for short) output by the electric power devices. The two groups of voltage transformers are the same voltage transformer and are connected in parallel and are positioned in a measuring circuit of the power equipment.
Fig. 3 is a flowchart of a method for monitoring disconnection of a transformer in a measurement circuit of an electrical device according to an embodiment of the present invention, and the apparatus for monitoring disconnection of a transformer in a measurement circuit of an electrical device includes the following specific steps:
and 301, acquiring voltage signal values of each phase output by the two groups of voltage transformers.
For example, as shown in fig. 5, the output circuit has three phases, i.e., a phase, B phase and C phase, and the three-phase lines corresponding to the voltage transformers are connected to the three phases of the output circuit respectively. In this embodiment, the device can continuously obtain the voltage signal values of the phases output by the two groups of voltage transformers, and perform subsequent real-time analysis.
For a three-phase four-wire output type electric power apparatus, a voltage signal value of each phase can be obtained by measuring a voltage of a line on one phase thereof; for a three-phase three-wire output type electric power device, the voltage signal value of each phase can be obtained by measuring the difference in line voltage between the two phases.
For example, if the voltage signal value output by one of the two voltage transformers corresponding to a is V1, and the voltage signal value output by the other line corresponding to a is V2, the absolute value | V1-V2| is greater than the preset threshold, and it is determined that one of the two voltage transformers is shorted.
According to the invention, the signal value acquisition and calculation of the current transformer in the measuring circuit are not involved in the monitoring process, the time cost is saved, and the open circuit of the voltage transformer in the measuring circuit of the power equipment is rapidly monitored.
Optionally, after step 302 of the method, the method further includes: and sending a blocking signal to a protection function unit in the measuring circuit, wherein the protection function unit is used for protecting the power equipment. Therefore, the power equipment can not be judged to be out of order by the locking protection functional unit according to the voltage signal output by the voltage transformer and the current signal output by the current transformer on the voltage and current output line of the power equipment, namely, the situation that the power equipment is controlled by mistake, such as the power equipment is controlled by mistake to be tripped by the voltage signal fault caused by the fact that the voltage transformer is broken is avoided. In the method, the method further comprises: according to the locking signal, one of the two groups of voltage transformers can be known and determined to be broken, manual maintenance is carried out, and after the maintenance, the locking of the protection function unit is opened, so that the whole measuring circuit continues to work normally.
In this process, in particular:
step 301 specifically includes: continuously acquiring voltage signal values of each phase output by the two groups of voltage transformers; specifically, the initial voltage signal values of the phases output by the two groups of voltage transformers in each measurement period can be continuously acquired. After the initial voltage signal value is subjected to analog-to-digital conversion, sampling values are obtained from the initial voltage signal value and are used as final voltage signal values of all phases output by the two groups of voltage transformers continuously;
step 302 may specifically preset a threshold value including:
and if the times that the absolute value of the difference value of the voltage signal values with the same phase exceeds the preset threshold value is continuously judged to be larger than or equal to the preset times value, determining that one of the two groups of voltage transformers is disconnected. For example, the preset value is 3 times.
Because the voltage signal value adopted in the judgment is the sampling value of the processed voltage signal, the time required for judging the open circuit of the voltage transformer and then reaching the locking protection functional unit is 5 milliseconds, and the time is greatly shortened. Therefore, the current signal of the current transformer applied to the output line of the power equipment is not needed, the comprehensive calculation based on the voltage signal and the current signal is not needed during calculation, the voltage signal and the current signal are not needed to be subjected to analog-to-digital conversion, and complex calculation of calculation modes such as Fourier transform and the like is not needed, and the method is simple and quick to implement.
In the method, the setting of the preset threshold is determined according to specific experiments, and the preset threshold cannot be too small to avoid misjudgment. Generally set to about 8% of the rated voltage of the transformer.
In the method, further, the method further comprises: after step 302, according to the determination result, it can also be determined which voltage transformer on the phase current line is disconnected. More specifically, it can be further determined which voltage transformer on which phase line of the power equipment output is open-circuited.
The method provided by the embodiment of the invention is suitable for three-phase three-wire output type power equipment; it is also applicable to three-phase four-wire output type electric power equipment. In which, for three-phase three-wire output type power equipment, the voltage signal value is taken as the difference in line voltage between two phase lines, e.g. VABRepresenting the difference in voltage signal values between the a and B phases. For a three-phase four-wire output type of electrical equipment, the voltage signal values are taken of the line voltages on each phase wire.
As a specific example of the three-phase four-wire output type electric power equipment, whether the voltage transformer is open-circuited is determined as follows.
Taking an a-phase output line of the power equipment as an example, in-phase voltage signals of two groups of voltage transformers are respectively called an a-phase voltage signal of a first voltage transformer and an a-phase voltage signal of a second voltage transformer.
If the absolute value of the difference value between the A-phase voltage signal of the first voltage transformer and the A-phase voltage signal of the second voltage transformer is larger than a preset threshold value, and the A-phase voltage signal of the first voltage transformer is smaller than the A-phase voltage signal of the second voltage transformer, the A-phase of the first voltage transformer is disconnected;
and if the absolute value of the difference value between the A-phase voltage signal of the first voltage transformer and the A-phase voltage signal of the second voltage transformer is greater than the preset threshold value, and the A-phase voltage signal of the first voltage transformer is greater than the A-phase voltage signal of the second voltage transformer, the A-phase of the second voltage transformer is disconnected.
The method is characterized in that a voltage signal value output by a line corresponding to the first voltage transformer and A is V1, a voltage signal value output by a line corresponding to the second voltage transformer and A is V2, if | V1-V2| is greater than a preset threshold value and V1 is less than V2, the first transformer is determined to be disconnected, and if | V1-V2| is greater than the preset threshold value and V1 is greater than V2, the second transformer is determined to be disconnected.
That is, for a three-phase four-wire output type power apparatus, the method further includes: and comparing the two in-phase voltage signal values, and determining that a group of voltage transformers with smaller voltage signal values are voltage transformers with broken circuits, and the corresponding phase is the phase with the broken circuit. The purpose of comparing the magnitudes of the voltage signal values is to determine a group of voltage transformers with smaller voltage signal values. This step may be performed after determining that the absolute value of the difference between the voltage signal values having the same phase exceeds a preset threshold.
For the three-phase three-wire output type power equipment, the open circuit judgment of the voltage transformer is as follows.
Taking an a-phase output line of the power equipment as an example, voltage signal values between two phases of two groups of voltage transformers are respectively called an inter-phase voltage signal value of a first voltage transformer and an inter-phase voltage signal value of a second voltage transformer, and are determined according to table one:
watch 1
As can be seen from table one, for a three-phase three-wire output type of power device, the method includes: and if the absolute value of the difference value between the two groups of voltage signal values in the same phase exceeds a preset threshold value, determining that one phase circuit shared by the two groups of voltage signal values in the same phase is broken. This step may be performed after determining that the absolute value of the difference between the voltage signal values having the same phase exceeds a preset threshold.
Specifically, for example, in table one, when absolute values of differences between voltage signal values of the AB phase and the BC phase of the first voltage transformer and the AB phase and the BC phase of the second voltage transformer are both greater than a preset threshold, the B phase line shared by the first voltage transformer and the second voltage transformer is disconnected. The difference between the first set of in-phase voltage signal values may specifically be a difference between a voltage signal value corresponding to AB of the first voltage transformer and a voltage signal value corresponding to AB of the second voltage transformer; the difference between the second set of in-phase voltages may specifically be a voltage signal value corresponding to the first voltage transformer BC and a voltage signal value corresponding to the second voltage transformer BC. For example, it may be determined whether a difference between voltage signal values of the same phase is greater than a preset threshold, and if so, it may be determined whether the number of the satisfied conditions is two, and if so, it may be determined that the common phase is open-circuited.
The interphase voltage signal value of the first voltage transformer corresponding to AB on the output line of the power equipment is expressed by a formula V1ABThe interphase voltage signal value of the second voltage transformer corresponding to AB on the output line of the power equipment is V2ABThe inter-phase voltage signal value of the first mutual inductor corresponding to BC on the output line of the power equipment is V1BCThe interphase voltage signal value of the second voltage transformer corresponding to BC on the output line of the power equipment is V2BCIf | V1AB-V2AB| V > Preset threshold and | V1BC-V2BC| > Preset thresholdAnd determining that the B phase is broken.
Here, the preset threshold is determined by a specific experiment and cannot be set too small so as not to generate a false judgment. Generally set to about 8% of the rated voltage of the transformer.
Therefore, the method provided by the embodiment of the invention can determine which phase circuit output by the electric power equipment is broken and perform subsequent processing.
According to the scheme, the embodiment of the invention does not need to be connected with any load circuit in series when the voltage transformer in the measuring circuit of the power equipment is monitored to be in an open circuit, and the circuit structure is simple.
Fig. 4 is a schematic structural diagram of an apparatus for monitoring disconnection of a voltage transformer in a measurement circuit of an electrical device according to an embodiment of the present invention, as shown in the figure, an output line of the electrical device is connected to two groups of identical voltage transformers 102, and the two groups of voltage transformers 102 are connected in parallel and included in the measurement circuit of the electrical device. Alternatively, the apparatus may be connected to the secondary lines of the two sets of voltage transformers 102, respectively.
The device includes:
a receiving module 401, configured to obtain voltage signal values of each phase output by the two groups of voltage transformers 102;
a determining module 402, configured to determine that one of the two sets of voltage transformers 102 is open-circuited if it is determined that the absolute value of the difference between the voltage signal values with the same phase exceeds a preset threshold.
The structure can be used for collecting and calculating the signal value of the current transformer in the measuring circuit in the monitoring process, so that the time cost is saved, and the open circuit of the voltage transformer in the measuring circuit of the power equipment can be rapidly monitored.
In this structure, the receiving module 401 is specifically configured to: continuously acquiring voltage signal values of each phase output by the two groups of voltage transformers; the determining module 402 is specifically configured to: and if the times that the absolute value of the difference value of the voltage signal values with the same phase exceeds the preset threshold value is continuously judged to be larger than or equal to the preset times value, determining that one of the two groups of voltage transformers is disconnected. Therefore, judgment and comparison of a plurality of monitoring periods are adopted in the monitoring process, and when the judgment and comparison are the same, which one of the two groups of voltage transformers is determined to be broken, so that the judgment is more accurate.
In this configuration, the power device is a three-phase four-wire output type power device, and the determination module 402 is further configured to: and comparing the two in-phase voltage signal values, and determining that the group of voltage transformers 102 with smaller voltage signal values are voltage transformers with broken circuits, and the corresponding phase is the phase with the broken circuit. In this way, it is possible to further accurately determine which phase of which one of the two groups of voltage transformers has the disconnection.
Or in this structure, the electric power equipment is a three-phase three-wire output type electric power equipment, and the voltage signal value is an absolute value of a difference value of line voltages between each two phases of the voltage transformer 102; the determination module 402 is further configured to: and if the absolute value of the difference value between the two groups of voltage signal values in the same phase exceeds a preset threshold value, determining that one phase circuit shared by the two groups of voltage signal values in the same phase is broken. In this way, it is possible to further accurately determine which phase of the two sets of voltage transformers has been disconnected.
In this configuration, a sending module 501 is configured to send a blocking signal to a protection function unit in the measurement circuit, where the protection function unit is configured to protect the power equipment.
The operation methods and corresponding advantageous effects of the above modules are the same as those of the foregoing embodiments, and are not described herein again.
Fig. 5 is a schematic structural diagram of a system for monitoring disconnection of a voltage transformer in a measurement circuit of an electrical device according to an embodiment of the present invention, as shown in the figure, the system includes: a measuring circuit of the power equipment and a monitoring voltage calculating unit 501, the output line of the power equipment is connected with two groups of same voltage transformers 102, the two groups of voltage transformers 102 are mutually connected in parallel and are included in the measuring circuit of the power equipment, the monitoring voltage calculating unit 501 can be respectively connected with the secondary lines of the two groups of voltage transformers 102, wherein,
the monitoring voltage calculation unit 501 obtains voltage signal values of each phase output by the two groups of voltage transformers 102; if the absolute value of the difference between the voltage signal values with the same phase is judged to exceed a preset threshold, it is determined that one of the two groups of voltage transformers 102 is open-circuited.
By adopting the system, the signal value acquisition and calculation of the current transformer in the measuring circuit are not involved in the monitoring process, the time cost is saved, and the open circuit of the voltage transformer in the measuring circuit of the power equipment is rapidly monitored.
In the system, the monitoring voltage calculating unit 501 is specifically configured to: continuously acquiring voltage signal values of each phase output by the two groups of voltage transformers; and if the times that the absolute value of the difference value of the voltage signal values with the same phase exceeds the preset threshold value is continuously judged to be larger than or equal to the preset times value, determining that one of the two groups of voltage transformers is disconnected. Therefore, judgment and comparison of a plurality of monitoring periods are adopted in the monitoring process, and when the judgment and comparison are the same, which one of the two groups of voltage transformers is determined to be broken, so that the judgment is more accurate.
In the system, the power equipment is a three-phase four-wire output type power equipment, the monitoring voltage calculation unit 501 is further configured to compare the magnitudes of two in-phase voltage signal values, and determine that a group of voltage transformers 102 with smaller voltage signal values is a voltage transformer with an open circuit, and the corresponding phase is the phase with the open circuit. In this way, it is possible to further accurately determine which phase of which one of the two groups of voltage transformers has the disconnection.
Alternatively, in the system, the power device is a three-phase three-wire output type power device, and the voltage signal value is an absolute value of a difference in line voltage between each two phases of the voltage transformer 102; the monitoring voltage calculating unit 501 is further configured to determine that a common phase line in corresponding phases of the two groups of in-phase voltage signal values is disconnected if an absolute value of a difference between the two groups of in-phase voltage signal values exceeds a preset threshold. In this way, it is possible to further accurately determine which phase of the two sets of voltage transformers has been disconnected.
In the system, the measurement circuit of the power equipment further includes a protection function unit 103, wherein the monitoring voltage calculation unit 501 is further configured to send a blocking signal to the protection function unit 103; the protection function unit 103 is configured to perform locking after receiving the locking signal. Therefore, the protection function unit 103 can be locked, and the protection function unit does not determine the state of the electric power equipment according to the voltage signal directly received from the voltage transformer and the current signal received from the current transformer, and the electric power equipment cannot be controlled by mistake.
The embodiment of the invention also provides a device for monitoring the disconnection of the voltage transformer in the measuring circuit of the power equipment. The device for measuring the disconnection of a voltage transformer in a circuit comprises at least one communication interface, at least one memory and at least one processor.
Wherein, at least one communication interface 601 is used for communicating with two groups of voltage transformers; at least one memory for storing voltage signal values; at least one processor 603 is connected to the communication interface 601 and the memory 602, and is configured to obtain voltage signal values of each phase output by two sets of voltage transformers through the communication interface, and store the voltage signal values in the memory, where the processor is configured to execute the method for monitoring disconnection of the voltage transformers in the measurement circuit of the power equipment according to any of the foregoing embodiments. The memory 602 may be provided in the processor 603 or may be provided separately.
Therefore, signal value collection and calculation of a current transformer in the measuring circuit are not involved in the monitoring process, time cost is saved, and disconnection of a voltage transformer in the measuring circuit of the power equipment is rapidly monitored.
The embodiment of the invention also provides a device for monitoring the disconnection of the voltage transformer in the measuring circuit of the power equipment. The apparatus for measuring the opening of a voltage transformer in a circuit includes at least one memory and at least one processor. Wherein the memory is to store instructions. The processor is configured to execute the method for monitoring disconnection of a voltage transformer in a measurement circuit of an electrical power device according to any one of the embodiments described above 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 monitoring for a potential transformer open circuit in a measurement circuit of an electrical power device as described in any of the embodiments above.
The readable medium has stored thereon machine readable instructions which, when executed by a processor, cause the processor to perform any of the methods previously described. In particular, a system or apparatus may be provided which is provided with a readable storage medium on which software program code implementing the functionality of any of the embodiments described above is stored and which causes a computer or processor of the system or apparatus to read and execute machine-readable instructions stored in the readable storage medium.
In this case, the program code itself read from the readable medium can realize 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 the readable storage medium 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 from the cloud via a communications network.
It will be understood by those skilled in the art that various changes and modifications may be made in the above-disclosed embodiments without departing from the spirit of the invention. Accordingly, the scope of the invention should be determined from the following claims.
It should be noted that not all steps, modules or units in the above flows and system structure diagrams are necessary, and some steps, modules or units may be omitted according to actual needs. The execution order 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 or modules may be implemented by the same physical entity, or some units or modules may be implemented by multiple physical entities, or some components in multiple independent devices may be implemented together.
In the above embodiments, the hardware unit or the hardware module may be implemented mechanically or electrically. For example, a hardware unit, hardware module, or processor may include permanent dedicated circuitry or logic (e.g., dedicated processor, FPGA or ASIC) to perform the corresponding operations. A hardware unit, hardware module, 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 specific implementation (mechanical, or dedicated permanent, or temporarily set) may be determined based on cost and time considerations.
While the invention has been shown and described in detail in the drawings and in the preferred embodiments, it is not intended to limit the invention to the embodiments disclosed, and it will be apparent to those skilled in the art that various combinations of the code auditing means in the various embodiments described above may be used to obtain further embodiments of the invention, which are also within the scope of the invention.
Claims (10)
1. The method for monitoring the open circuit of the voltage transformer in the measuring circuit of the power equipment is characterized in that the output line of the power equipment is connected with two groups of same voltage transformers, the two groups of voltage transformers are mutually connected in parallel and are positioned in the measuring circuit of the power equipment, and the method comprises the following steps:
acquiring voltage signal values of each phase output by the two groups of voltage transformers;
if the absolute value of the difference value between the voltage signal values with the same phase exceeds a preset threshold value, determining that one of the two groups of voltage transformers is broken and determining the phase with the broken circuit;
the power equipment is a three-phase four-wire output type power equipment, and the determining of the phase with the broken circuit comprises the following steps:
comparing the magnitude of the two in-phase voltage signal values, and determining that a group of voltage transformers with smaller voltage signal values are voltage transformers with broken circuits, and the corresponding phase is the phase with the broken circuit; or
The power equipment is a three-phase three-wire output type power equipment, the voltage signal value is the difference value of line voltage between each two phases of the voltage transformer, and the phase which is determined to be broken comprises the following steps:
and if the absolute value of the difference value between the two groups of voltage signal values in the same phase exceeds a preset threshold value, determining that one phase circuit shared by the two groups of voltage signal values in the same phase is broken.
2. The method of claim 1, wherein obtaining respective corresponding voltage signal values output by two of the sets of voltage transformers comprises:
continuously acquiring voltage signal values of each phase output by the two groups of voltage transformers;
if the absolute value of the difference value between the voltage signal values with the same phase exceeds a preset threshold value, the step of breaking one of the two groups of voltage transformers comprises the following steps:
and if the times that the absolute value of the difference value of the voltage signal values with the same phase exceeds the preset threshold value is continuously judged to be larger than or equal to the preset times value, determining that one of the two groups of voltage transformers is broken.
3. The method of claim 1, wherein the preset threshold is 8% of a rated voltage of the voltage transformer.
4. The method of any of claims 1-3, after determining that one of the two sets of voltage transformers is open, further comprising:
and sending a blocking signal to a protection function unit in the measuring circuit, wherein the protection function unit is used for protecting the power equipment.
5. Device for monitoring the breaking of voltage transformers in a measuring circuit of an electrical apparatus, the output line of which connects two identical sets of voltage transformers (102), the two sets of voltage transformers (102) being connected in parallel to each other and being included in the measuring circuit of the electrical apparatus, characterized in that the device comprises:
a receiving module (401) for acquiring voltage signal values of each phase output by the two groups of voltage transformers (102);
a decision module (402) for determining that one of the two sets of voltage transformers (102) is open-circuited and determining the phase in which the open-circuit occurs if it is determined that the absolute value of the difference between the voltage signal values having the same phase exceeds a preset threshold;
the power device is of the three-phase four-wire output type, the decision module (402) being further configured to: comparing the magnitude of the two in-phase voltage signal values, and determining that a group of voltage transformers (102) with smaller voltage signal values are voltage transformers with broken circuits, and the corresponding phase is the phase with the broken circuit; or
The power equipment is of a three-phase three-wire output type, and the voltage signal value is the difference value of line voltage between each two phases of the voltage transformer (102); the determination module (402) is further configured to: and if the absolute value of the difference value between the two groups of voltage signal values in the same phase exceeds a preset threshold value, determining that one phase circuit shared by the two groups of voltage signal values in the same phase is broken.
6. The apparatus of claim 5,
the receiving module (401) is specifically configured to: continuously acquiring voltage signal values of each phase output by the two groups of voltage transformers;
the determination module (402) is specifically configured to: and if the times that the absolute value of the difference value of the voltage signal values with the same phase exceeds the preset threshold value is continuously judged to be larger than or equal to the preset times value, determining that one of the two groups of voltage transformers is broken.
7. The apparatus of claim 5 or 6, further comprising:
and the sending module (501) is used for sending a blocking signal to a protection function unit in the measuring circuit, and the protection function unit is used for protecting the power equipment.
8. Device for monitoring the disconnection of voltage transformers in a measuring circuit of an electrical apparatus, the output line of which is connected to two identical sets of voltage transformers (102), the two sets of voltage transformers (102) being connected in parallel to each other and being included in the measuring circuit of the electrical apparatus, characterized in that it comprises:
at least one communication interface for communicating with two sets of said voltage transformers;
at least one memory for storing voltage signal values;
at least one processor, connected to the communication interface and the memory, for acquiring voltage signal values of each phase output by the two sets of voltage transformers through the communication interface and storing the voltage signal values in the memory, wherein the processor is configured to execute the method for monitoring the open circuit of the voltage transformers in the measurement circuit of the power equipment according to any one of claims 1 to 4.
9. Device for monitoring the disconnection of voltage transformers in a measuring circuit of an electrical apparatus, the output line of which is connected to two identical sets of voltage transformers (102), the two sets of voltage transformers (102) being connected in parallel to each other and being included in the measuring circuit of the electrical apparatus, characterized in that it comprises:
at least one memory for storing instructions;
at least one processor configured to execute the method of monitoring for a voltage transformer break in a measurement circuit of an electrical power device according to any one of claims 1-4 in accordance with instructions stored in the memory.
10. Readable storage medium, in which machine readable instructions are stored, which when executed by a machine, perform a method of monitoring a voltage transformer break in a measurement circuit of an electrical power device according to any one of claims 1-4.
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| CN201810691267.8A CN108627795B (en) | 2018-06-28 | 2018-06-28 | Method and device for monitoring open circuit of voltage transformer in measuring circuit of power equipment |
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| CN111751777B (en) * | 2020-06-29 | 2024-03-01 | 深圳供电局有限公司 | Voltage transformer running state diagnosis method |
| CN112285634B (en) * | 2020-12-18 | 2021-03-23 | 华中科技大学 | Method for identifying abnormal measurement error of high-voltage transformer in double-bus structure |
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| JPS5890183A (en) * | 1981-11-25 | 1983-05-28 | Fuji Electric Co Ltd | Detecting system for fault of circuit of transformer for meters |
| JPH08154336A (en) * | 1994-11-29 | 1996-06-11 | Kawasaki Steel Corp | Open-circuit detector for instrument current transformer secondary side |
| CN101620262B (en) * | 2009-06-29 | 2011-08-31 | 江苏省电力公司苏州供电公司 | Fault monitoring method of operating capacitive voltage transformer |
| CN102508191B (en) * | 2011-12-23 | 2015-04-01 | 中国北车集团大连机车车辆有限公司 | Device and method for detecting fault of high voltage transformer of electric locomotive |
| CN102879630A (en) * | 2012-09-17 | 2013-01-16 | 浙江省电力公司电力科学研究院 | Capacitive voltage transformer failure monitoring instrument |
| JP6335040B2 (en) * | 2014-06-20 | 2018-05-30 | 株式会社東芝 | Vehicle control device |
| CN104035001B (en) * | 2014-06-25 | 2016-03-16 | 国家电网公司 | A kind of detection method of voltage transformer disconnection |
| CN206945855U (en) * | 2017-07-04 | 2018-01-30 | 上海纳信实业有限公司 | A kind of excitation system voltage transformer fault detection module |
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