CN114791573A - Method, device, equipment and medium for detecting fault of uncontrolled rectifier bridge port side - Google Patents
Method, device, equipment and medium for detecting fault of uncontrolled rectifier bridge port side Download PDFInfo
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Abstract
The application discloses a method, a device, equipment and a medium for detecting the fault of an uncontrolled rectifier bridge port side, wherein the method comprises the following steps: obtaining a line voltage measuring signal of an uncontrolled rectifier bridge, and constructing six-pulse wave rectification voltage of a direct current output side of the uncontrolled rectifier bridge under the condition of open circuit; obtaining an estimated bus voltage at the output side of the uncontrolled rectifier bridge according to the voltage; respectively extracting a first pulse amplitude and a second pulse amplitude of the estimated bus voltage and the actually-measured bus voltage under 300Hz, and extracting a third pulse amplitude of the six-pulse rectification voltage under 100 Hz; determining whether the bus capacitor on the output side of the uncontrolled rectifier bridge is aged or not according to the first pulsation amplitude and the second pulsation amplitude; and acquiring a direct-current component of the six-pulse rectification voltage, and determining whether the power grid voltage on the input side of the uncontrolled rectifier bridge has an unbalanced fault or not according to the direct-current component and the third pulse amplitude. By the method, the reliability of the fault detection result of the power grid voltage and the bus capacitor can be ensured on the premise of not increasing the hardware detection cost.
Description
Technical Field
The invention relates to the technical field of frequency converters, in particular to a method, a device, equipment and a medium for detecting a fault on an uncontrolled rectifier bridge port side.
Background
In the field of industrial three-phase frequency converter driving, an uncontrolled rectifier bridge is a standard rectification scheme. After the voltage of a power grid is rectified, the uncontrolled rectifier bridge can provide direct-current voltage for the inverter after being filtered by the bus capacitor. In the operation process of the uncontrolled rectifier bridge, when the voltage of a power grid is seriously unbalanced or a direct current bus capacitor is aged, the output response of the inverter is deteriorated, so that the safe and stable operation of the inverter is seriously influenced. Therefore, in practical applications, the two types of faults need to be detected and processed in real time.
In the prior art, for the unbalanced fault of the power grid voltage, a common hardware detection method is to compare effective values of three-phase line voltages by a hardware comparator to determine whether the power grid voltage is unbalanced, but the method not only increases the detection cost, but also makes the fault threshold difficult to adjust. Or the effective value of the three-phase line voltage is calculated through software to determine whether the power grid voltage has an unbalanced fault, however, the method cannot distinguish other loads (such as power frequency fans) connected in parallel at the input side of the uncontrolled rectifier bridge, and thus misjudgment of the detection result is caused. For the aging fault of the bus capacitor, a common hardware detection method is to determine the aging fault of the bus capacitor by detecting the ripple current of the bus, but this method needs to add an additional current sensor, which increases the detection cost of the bus capacitor. Or, the voltage and current signals of the bus are estimated online by software to judge whether the aging fault occurs in the bus capacitor, but the method not only needs a complex online parameter estimation algorithm, but also is easily influenced by the current measurement value.
Therefore, how to realize fault detection of the power grid voltage and the bus capacitor and ensure the reliability of a fault detection result on the premise of not increasing the hardware detection cost is a technical problem to be solved urgently by technical personnel in the field.
Disclosure of Invention
In view of the above, the present invention provides a method, an apparatus, a device, and a medium for detecting a fault at an uncontrolled rectifier bridge port side, so as to ensure reliability of a fault detection result of a grid voltage and a bus capacitor without increasing hardware detection cost. The specific scheme is as follows:
a method for detecting a fault on the port side of an uncontrolled rectifier bridge comprises the following steps:
obtaining a line voltage measuring signal of an uncontrolled rectifier bridge, and constructing a six-pulse wave rectified voltage of a direct current output side of the uncontrolled rectifier bridge under the condition of circuit breaking according to the line voltage measuring signal;
acquiring an estimated bus voltage of the direct current output side of the uncontrolled rectifier bridge according to the six-pulse wave rectified voltage;
respectively extracting the pulse amplitude of the estimated bus voltage and the actually-measured bus voltage under 300Hz to obtain a first pulse amplitude and a second pulse amplitude, and extracting the pulse amplitude of the six-pulse rectification voltage under 100Hz to obtain a third pulse amplitude;
determining whether the bus capacitor on the direct current output side of the uncontrolled rectifier bridge is aged or not according to the first pulsation amplitude and the second pulsation amplitude;
and acquiring a direct-current component of the six-pulse wave rectified voltage, and determining whether the power grid voltage on the input side of the uncontrolled rectifier bridge has an unbalanced fault or not according to the direct-current component and the third pulse amplitude.
Preferably, the process of obtaining a line voltage measurement signal of the uncontrolled rectifier bridge and constructing a six-pulse wave rectified voltage of the dc output side of the uncontrolled rectifier bridge under the condition of the open circuit according to the line voltage measurement signal includes:
obtaining the line voltage measuring signal u of the uncontrolled rectifier bridge RS 、u ST And u TR And according to the first target model, the line voltage measuring signal u RS 、u ST And u TR Constructing the six-pulse wave rectification voltage of the direct current output side of the uncontrolled rectifier bridge under the condition of circuit breaking;
wherein the expression of the first target model is:
u rect ＝max(|u RS |,|u ST |,|u TR |)；
in the formula u rect Rectifying the voltage u for said six-pulse wave RS Is the voltage value between the R phase and the S phase on the uncontrolled rectifier bridge u ST Is the voltage value between S phase and T phase on the uncontrolled rectifier bridge u TR And the voltage value between the T phase and the R phase on the uncontrolled rectifier bridge is obtained.
Preferably, the process of obtaining the estimated bus voltage at the dc output side of the uncontrolled rectifier bridge according to the six-pulse wave rectified voltage includes:
acquiring the estimated bus voltage at the direct current output side of the uncontrolled rectifier bridge according to a second target model and the six-pulse wave rectified voltage;
wherein the expression of the second target model is:
in the formula (I), the compound is shown in the specification,
estimated bus voltage, u, at time t rect Rectifying the voltage, R, for said six-pulse wave dc And C dc Respectively an equivalent resistor and an equivalent capacitor at the direct current output side of the uncontrolled rectifier bridge.
Preferably, the process of respectively extracting the pulsation amplitudes of the estimated bus voltage and the actually measured bus voltage at 300Hz to obtain a first pulsation amplitude and a second pulsation amplitude includes:
extracting a harmonic signal of the estimated bus voltage under 300Hz by using a second-order Butterworth filter to obtain a first harmonic signal, and performing absolute value operation and low-pass filtering on the first harmonic signal to obtain a first pulsation amplitude;
and extracting a harmonic signal of the actually measured bus voltage under 300Hz by using the second-order Butterworth filter to obtain a second harmonic signal, and performing absolute value operation and low-pass filtering on the second harmonic signal to obtain the second pulsation amplitude.
Preferably, the determining whether the bus capacitance on the dc output side of the uncontrolled rectifier bridge is aged according to the first ripple amplitude and the second ripple amplitude includes:
and if the first pulsation amplitude and the second pulsation amplitude meet a preset judgment condition, judging that the bus capacitor on the direct current output side of the uncontrolled rectifier bridge is aged.
Preferably, the process of determining whether an unbalanced fault occurs in the grid voltage at the input side of the uncontrolled rectifier bridge according to the dc component and the third ripple amplitude includes:
performing per unit processing on the third pulsation amplitude by taking the direct current component as a reference value to obtain a target value;
and if the target value is greater than a preset threshold value and the duration of the target value greater than the preset threshold value is greater than a preset duration, judging that the power grid voltage on the input side of the uncontrolled rectifier bridge has an unbalanced fault.
Correspondingly, the invention also discloses a fault detection device at the port side of the uncontrolled rectifier bridge, which comprises the following components:
the voltage construction module is used for obtaining a line voltage measuring signal of the uncontrolled rectifier bridge and constructing six-pulse wave rectified voltage of the direct current output side of the uncontrolled rectifier bridge under the condition of circuit breaking according to the line voltage measuring signal;
the voltage estimation module is used for acquiring the estimated bus voltage of the direct current output side of the uncontrolled rectifier bridge according to the six-pulse wave rectified voltage;
the amplitude extraction module is used for respectively extracting the pulse amplitudes of the estimated bus voltage and the actually measured bus voltage under 300Hz to obtain a first pulse amplitude and a second pulse amplitude, and extracting the pulse amplitudes of the six-pulse rectification voltage under 100Hz to obtain a third pulse amplitude;
the first judging module is used for determining whether the bus capacitor on the direct current output side of the uncontrolled rectifier bridge is aged or not according to the first pulsation amplitude and the second pulsation amplitude;
and the second judgment module is used for acquiring the direct-current component of the six-pulse wave rectified voltage and determining whether the power grid voltage on the input side of the uncontrolled rectifier bridge has an unbalanced fault or not according to the direct-current component and the third pulse amplitude.
Correspondingly, the invention also discloses a fault detection device at the port side of the uncontrolled rectifier bridge, which comprises:
a memory for storing a computer program;
a processor for implementing the steps of a method for uncontrolled bridge port side fault detection as disclosed in the foregoing when executing said computer program.
Accordingly, the present invention also discloses a computer readable storage medium, on which a computer program is stored, which computer program, when being executed by a processor, implements the steps of the method for detecting a fault on the port side of an uncontrolled rectifier bridge as disclosed in the foregoing.
Therefore, in the invention, in order to detect the power grid voltage and the bus capacitor at the port side of the uncontrolled rectifier bridge, firstly, a line voltage measuring signal of the uncontrolled rectifier bridge is obtained, and a six-pulse wave rectified voltage of the direct current output side of the uncontrolled rectifier bridge under the condition of circuit breaking is constructed according to the line voltage measuring signal; then, obtaining an estimated bus voltage at the direct current output side of the uncontrolled rectifier bridge according to the six-pulse rectification voltage, respectively extracting the pulse amplitudes of the estimated bus voltage and the actually-measured bus voltage under 300Hz to obtain a first pulse amplitude and a second pulse amplitude, and extracting the pulse amplitudes of the six-pulse rectification voltage under 100Hz to obtain a third pulse amplitude; then, determining whether the bus capacitor on the direct current output side of the uncontrolled rectifier bridge is aged or not according to the first pulsation amplitude and the second pulsation amplitude; and finally, acquiring the direct-current component of the six-pulse wave rectified voltage, and determining whether the power grid voltage on the input side of the uncontrolled rectifier bridge has an unbalanced fault according to the direct-current component and the third pulse amplitude. Compared with the prior art, the method does not need to additionally add a hardware detection circuit, can judge whether the grid voltage and the bus capacitor at the port side of the uncontrolled rectifier bridge have faults or not only by some simple measurement signals and calculation transformation, and can not be interfered by other factors, so that the reliability of the fault detection result of the grid voltage and the bus capacitor can be ensured on the premise of not increasing the hardware detection cost. Correspondingly, the fault detection device, the equipment and the medium for the uncontrolled rectifier bridge port, which are provided by the invention, also have the beneficial effects.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a flowchart of a method for detecting a fault on an uncontrolled rectifier bridge port side according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an uncontrolled rectifier bridge;
FIG. 3 is a schematic diagram of extracting the amplitude of the pulsation in the estimated bus voltage and the measured bus voltage;
FIG. 4 is a block diagram of a fault detection device at the port side of an uncontrolled rectifier bridge according to an embodiment of the present invention;
fig. 5 is a structural diagram of a fault detection device on the port side of an uncontrolled rectifier bridge according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a flowchart of a method for detecting a fault at an uncontrolled rectifier bridge port side according to an embodiment of the present invention, where the method includes:
step S11: obtaining a line voltage measuring signal of the uncontrolled rectifier bridge, and constructing a six-pulse wave rectification voltage of the direct current output side of the uncontrolled rectifier bridge under the condition of circuit breaking according to the line voltage measuring signal;
step S12: acquiring an estimated bus voltage at the direct current output side of the uncontrolled rectifier bridge according to the six-pulse wave rectified voltage;
step S13: respectively extracting the pulsation amplitude of the estimated bus voltage and the pulsation amplitude of the actually measured bus voltage under 300Hz to obtain a first pulsation amplitude and a second pulsation amplitude, and extracting the pulsation amplitude of the six-pulse rectification voltage under 100Hz to obtain a third pulsation amplitude;
step S14: determining whether the bus capacitor on the direct current output side of the uncontrolled rectifier bridge is aged or not according to the first pulsation amplitude and the second pulsation amplitude;
step S15: and acquiring a direct-current component of the six-pulse-wave rectified voltage, and determining whether the power grid voltage on the input side of the uncontrolled rectifier bridge has an unbalanced fault or not according to the direct-current component and the third pulse amplitude.
In this embodiment, a method for detecting a fault at an uncontrolled rectifier bridge port side is provided, and the method is used to detect a grid voltage and a bus capacitor at the uncontrolled rectifier bridge port side, so that not only can reliability of a fault detection result of the grid voltage and the bus capacitor be ensured, but also hardware detection cost is not increased.
In the method, firstly, a line voltage measuring signal of an uncontrolled rectifier bridge is obtained, and a six-pulse wave rectification voltage of the direct current output side of the uncontrolled rectifier bridge under the condition of circuit breaking is constructed according to the line voltage measuring signal of the uncontrolled rectifier bridge. After the six-pulse wave rectified voltage of the direct current output side of the uncontrolled rectifier bridge under the condition of circuit breaking is constructed, the six-pulse wave rectified voltage and the bus voltage of the direct current output side of the uncontrolled rectifier bridge are related on a circuit model, so that the estimated bus voltage of the direct current output side of the uncontrolled rectifier bridge can be obtained according to the six-pulse wave rectified voltage.
It can be understood that when the grid voltage at the input side of the uncontrolled rectifier bridge normally operates, the vector sum of the three-phase voltage at the input side of the uncontrolled rectifier bridge is 0, at this time, only a ripple amplitude of 300Hz exists in the six-pulse-wave rectified voltage and the bus voltage, and if the bus capacitor at the direct current output side of the uncontrolled rectifier bridge is not aged, the ripple amplitude of the bus voltage at 300Hz is estimated to keep a certain proportional relationship with the ripple amplitude of the bus voltage at 300Hz actually measured, so that whether the bus capacitor at the direct current output side of the uncontrolled rectifier bridge is aged can be judged according to the ripple amplitude of the estimated bus voltage and the actually measured bus voltage at 300 Hz.
Specifically, after the estimated bus voltage and the actually measured bus voltage are obtained, the ripple amplitudes of the estimated bus voltage and the actually measured bus voltage at 300Hz are respectively extracted to obtain a first ripple amplitude and a second ripple amplitude, and then whether the bus capacitor on the direct current output side of the uncontrolled rectifier bridge is aged or not is determined according to the first ripple amplitude and the second ripple amplitude.
If the grid voltage on the input side of the uncontrolled rectifier bridge has an unbalanced fault, the vector sum of the three-phase voltages on the input side of the uncontrolled rectifier bridge is no longer 0, and besides the ripple amplitude of 300Hz corresponding to the six-pulse wave rectified voltage, the ripple amplitude of 100Hz caused by the grid voltage unbalance exists in the bus voltage. Therefore, in practical applications, in order to detect whether an unbalanced fault occurs in the grid voltage at the input side of the uncontrolled rectifier bridge, it is further necessary to extract a ripple amplitude of the six-pulse rectified voltage at 100Hz, that is, to extract a third ripple amplitude of the six-pulse rectified voltage at 100 Hz.
After the third ripple amplitude of the six-pulse wave rectified voltage under 100Hz is obtained, whether the power grid voltage on the input side of the uncontrolled rectifier bridge has an unbalanced fault or not can be judged by comparing the third ripple amplitude of the six-pulse wave rectified voltage under 100Hz with the direct-current component of the six-pulse wave rectified voltage.
The method can judge whether the grid voltage and the bus capacitor at the port side of the uncontrolled rectifier bridge have faults or not only by simple measurement signals and calculation conversion without additionally adding a hardware detection circuit, and can not be interfered by other factors, so that the reliability of the fault detection results of the grid voltage and the bus capacitor can be ensured on the premise of not increasing the hardware detection cost.
Therefore, in the embodiment, in order to detect the power grid voltage and the bus capacitor at the port side of the uncontrolled rectifier bridge, firstly, a line voltage measurement signal of the uncontrolled rectifier bridge is obtained, and a six-pulse wave rectified voltage of the direct current output side of the uncontrolled rectifier bridge under the condition of circuit breaking is constructed according to the line voltage measurement signal; then, according to the six-pulse rectification voltage, obtaining an estimated bus voltage on the direct-current output side of the uncontrolled rectifier bridge, respectively extracting the pulse amplitude values of the estimated bus voltage and the actually measured bus voltage under 300Hz to obtain a first pulse amplitude value and a second pulse amplitude value, and extracting the pulse amplitude values of the six-pulse rectification voltage under 100Hz to obtain a third pulse amplitude value; then, determining whether the bus capacitor on the direct current output side of the uncontrolled rectifier bridge is aged or not according to the first pulsation amplitude and the second pulsation amplitude; and finally, acquiring the direct-current component of the six-pulse wave rectified voltage, and determining whether the power grid voltage on the input side of the uncontrolled rectifier bridge has an unbalanced fault according to the direct-current component and the third pulse amplitude. Compared with the prior art, the method does not need to additionally add a hardware detection circuit, can judge whether the grid voltage and the bus capacitor at the port side of the uncontrolled rectifier bridge have faults or not only by some simple measurement signals and calculation transformation, and can not be interfered by other factors, so that the reliability of the fault detection results of the grid voltage and the bus capacitor can be ensured on the premise of not increasing the hardware detection cost.
Based on the above embodiment, this embodiment further describes and optimizes the technical solution, and as a preferred implementation, the above steps: the method comprises the following steps of obtaining a line voltage measuring signal of an uncontrolled rectifier bridge, and constructing a six-pulse wave rectified voltage process of a direct current output side of the uncontrolled rectifier bridge under the condition of circuit breaking according to the line voltage measuring signal, wherein the six-pulse wave rectified voltage process comprises the following steps:
obtaining a line voltage measurement signal u of an uncontrolled rectifier bridge RS 、u ST And u TR And according to the first target model, the line voltage measurement signal u RS 、u ST And u TR Constructing six-pulse wave rectification voltage of the direct current output side of the uncontrolled rectifier bridge under the condition of circuit breaking;
wherein the expression of the first target model is:
u rect ＝max(|u RS |,|u ST |,|u TR |)；
in the formula u rect For six-pulse rectified voltage u RS For the voltage value between the R-phase and the S-phase on an uncontrolled rectifier bridge, u ST For the voltage value between S-phase and T-phase on an uncontrolled rectifier bridge, u TR The voltage value between the T phase and the R phase on the uncontrolled rectifier bridge.
Referring to fig. 2, fig. 2 is a schematic diagram of an uncontrolled rectifier bridge. When constructing the six-pulse wave rectified voltage at the DC output side of the uncontrolled rectifier bridge, firstly, a line voltage measuring signal u of the uncontrolled rectifier bridge is obtained RS 、u ST And u TR Wherein u is RS For the voltage value between the R-phase and the S-phase on an uncontrolled rectifier bridge, u ST For the voltage value between S-phase and T-phase on an uncontrolled rectifier bridge, u TR The voltage value between the T phase and the R phase on the uncontrolled rectifier bridge is obtained; then, according to the first target model and the line voltage measuring signal u RS 、u ST And u TR To construct a six-pulse wave rectified voltage u under the condition of open circuit of the direct current output side of the uncontrolled rectifier bridge rect 。
As a preferred embodiment, the above steps: the process of obtaining the estimated bus voltage of the direct current output side of the uncontrolled rectifier bridge according to the six-pulse wave rectified voltage comprises the following steps:
acquiring an estimated bus voltage of the direct current output side of the uncontrolled rectifier bridge according to the second target model and the six-pulse wave rectified voltage;
wherein the expression of the second target model is:
in the formula (I), the compound is shown in the specification,
for estimation of time tMeasuring bus voltage u rect For a six-pulse wave rectified voltage, R dc And C dc Respectively an equivalent resistor and an equivalent capacitor at the direct current output side of the uncontrolled rectifier bridge.
It can be understood that, due to the influence of the tube voltage drop in the uncontrolled rectifier bridge and the parasitic resistance in the commutation loop, a certain deviation exists between the bus voltage at the dc output side of the uncontrolled rectifier bridge and the six-pulse-wave rectified voltage, so in practical application, the estimated bus voltage at the dc output side of the uncontrolled rectifier bridge can be equivalent to the low-pass filtering result of the six-pulse-wave rectified voltage. In particular, the voltage u may be rectified according to a second target model and a six-pulse wave rect To obtain the estimated bus voltage u of the DC output side of the uncontrolled rectifier bridge dc 。
Based on the above embodiment, this embodiment further describes and optimizes the technical solution, and as a preferred implementation, the above steps: the process of extracting the pulse amplitude of the estimated bus voltage and the actually measured bus voltage under 300Hz respectively to obtain a first pulse amplitude and a second pulse amplitude comprises the following steps:
extracting harmonic signals of the estimated bus voltage under 300Hz by using a second-order Butterworth filter to obtain first harmonic signals, and performing absolute value operation and low-pass filtering on the first harmonic signals to obtain first pulsation amplitude values;
and extracting a harmonic signal of the actually measured bus voltage under 300Hz by using a second-order Butterworth filter to obtain a second harmonic signal, and performing absolute value operation and low-pass filtering on the second harmonic signal to obtain a second pulsation amplitude.
Referring to fig. 3, fig. 3 is a schematic diagram of extracting the amplitude of the pulsation in the estimated bus voltage and the measured bus voltage. When extracting the pulsation amplitude of the estimated bus voltage at 300Hz, the cut-off frequency f of the second-order Butterworth filter can be firstly used h Set to 300Hz and cut-off frequency f of the low-pass filter c Is set to be far lower than f h The value of (c). Thus, when the pulsation amplitude of the estimated bus voltage under 300Hz is extracted, the harmonic signal of the estimated bus voltage under 300Hz can be extracted by utilizing a second-order Butterworth filter to obtain a first harmonic signalThen, absolute value operation and low-pass filtering are carried out on the first harmonic signal by using an absolute value function and a low-pass filter, and a first pulsation amplitude U of the estimated bus voltage under 300Hz can be extracted recth6 。
When extracting the pulsation amplitude of the actually measured bus voltage under 300Hz, the cut-off frequency f of the second-order Butterworth filter can be firstly detected h Set to 300Hz and cut-off frequency f of the low-pass filter c Is set to be far below f h The value of (c). Therefore, when the pulsation amplitude of the actual measured bus voltage under 300Hz is extracted, the harmonic signal of the actual measured bus voltage under 300Hz can be extracted by using the second-order Butterworth filter to obtain the second harmonic signal, and then the absolute value function and the low-pass filter are used for carrying out absolute value operation and low-pass filtering on the second harmonic signal, so that the second pulsation amplitude U of the actual measured bus voltage under 300Hz can be extracted dch6 。
Similarly, when extracting the ripple amplitude of the six-pulse rectified voltage at 100Hz, the cut-off frequency f of the second-order Butterworth filter can be firstly used h Set to 100Hz and cut-off frequency f of the low-pass filter c Is set to be far lower than f h The value of (c). Therefore, when the ripple amplitude of the six-pulse rectification voltage under 100Hz is extracted, the second-order Butterworth filter can be used for extracting the harmonic signal of the six-pulse rectification voltage under 100Hz to obtain a third harmonic signal, and then the third harmonic signal is subjected to absolute value operation and low-pass filtering to obtain a third ripple amplitude U of the six-pulse rectification voltage under 100Hz recth2 。
Based on the above embodiments, this embodiment further describes and optimizes the technical solution, and as a preferred implementation, the above steps: the method for determining whether the bus capacitor on the direct current output side of the uncontrolled rectifier bridge is aged or not according to the first ripple amplitude and the second ripple amplitude comprises the following steps:
and if the first pulsation amplitude and the second pulsation amplitude meet the preset judgment condition, judging that the bus capacitor on the direct current output side of the uncontrolled rectifier bridge is aged.
In practical application, whether the bus capacitor on the direct current output side of the uncontrolled rectifier bridge is aged or not can be judged through a preset judgment condition. Specifically, the expression of the preset judgment condition is as follows:
in the formula of U recth6 Is the amplitude of the second pulsation in the form of a second pulsation,
is a first pulsation amplitude.
I.e. when the second pulsation amplitude U is greater recth6 A first pulsation amplitude greater than 2 times
When the bus capacitor is aged, the bus capacitor on the direct current output side of the uncontrolled rectifier bridge is shown to be aged; if the second pulsation amplitude U recth6 A first pulsation amplitude less than or equal to 2 times
The bus capacitor on the direct current output side of the uncontrolled rectifier bridge is not aged.
Obviously, when the bus capacitor is judged to be aged through the mathematical model, the aging judgment result of the bus capacitor can be more accurate and reliable.
Based on the above embodiments, this embodiment further describes and optimizes the technical solution, and as a preferred implementation, the above steps: the process of determining whether the grid voltage at the input side of the uncontrolled rectifier bridge has an unbalanced fault according to the direct current component and the third pulsation amplitude comprises the following steps:
performing per unit processing on the third pulsation amplitude by taking the direct-current component as a reference value to obtain a target value;
and if the target value is greater than the preset threshold value and the duration of the target value greater than the preset threshold value is greater than the preset duration, judging that the power grid voltage on the input side of the uncontrolled rectifier bridge has an unbalanced fault.
When judging whether the power grid voltage at the input side of the uncontrolled rectifier bridge has an unbalanced fault, per-unit processing can be performed on a third pulse amplitude value of the six-pulse rectified voltage under 100Hz by taking a direct-current component of the six-pulse rectified voltage as a reference value to obtain a target value; and if the target value is greater than the preset threshold value and the duration of the target value being greater than the preset threshold value is greater than the preset duration, indicating that the grid voltage on the input side of the uncontrolled rectifier bridge has an unbalanced fault. And if the target value is smaller than the preset threshold value, or the target value is larger than the preset threshold value, but the duration of the target value larger than the preset threshold value is smaller than or equal to the preset duration, indicating that the power grid voltage at the input side of the uncontrolled rectifier bridge is still in a balanced state.
Referring to fig. 4, fig. 4 is a structural diagram of a fault detection apparatus at an uncontrolled rectifier bridge port side according to an embodiment of the present invention, where the apparatus includes:
the voltage construction module 21 is configured to obtain a line voltage measurement signal of the uncontrolled rectifier bridge, and construct a six-pulse wave rectified voltage of the uncontrolled rectifier bridge on the direct current output side under the condition of a circuit break according to the line voltage measurement signal;
the voltage estimation module 22 is used for acquiring an estimated bus voltage at the direct current output side of the uncontrolled rectifier bridge according to the six-pulse wave rectified voltage;
the amplitude extraction module 23 is configured to extract the pulsation amplitudes of the estimated bus voltage and the actually measured bus voltage at 300Hz respectively to obtain a first pulsation amplitude and a second pulsation amplitude, and extract the pulsation amplitudes of the six-pulse rectification voltage at 100Hz to obtain a third pulsation amplitude;
the first judging module 24 is configured to determine whether a bus capacitor on the dc output side of the uncontrolled rectifier bridge is aged according to the first ripple amplitude and the second ripple amplitude;
and the second judging module 25 is configured to obtain a direct-current component of the six-pulse rectified voltage, and determine whether an unbalanced fault occurs in the power grid voltage at the input side of the uncontrolled rectifier bridge according to the direct-current component and the third ripple amplitude.
The fault detection device on the port side of the uncontrolled rectifier bridge provided by the embodiment of the invention has the beneficial effects of the fault detection method on the port side of the uncontrolled rectifier bridge disclosed by the embodiment of the invention.
Referring to fig. 5, fig. 5 is a structural diagram of a fault detection device on an uncontrolled rectifier bridge port side according to an embodiment of the present invention, where the fault detection device includes:
a memory 31 for storing a computer program;
a processor 32 for implementing the steps of a method for detecting a fault on the port side of an uncontrolled rectifier bridge as disclosed in the foregoing when executing a computer program.
The fault detection equipment on the port side of the uncontrolled rectifier bridge provided by the embodiment of the invention has the beneficial effects of the fault detection method on the port side of the uncontrolled rectifier bridge.
Correspondingly, the embodiment of the present invention further discloses a computer readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the method for detecting a fault on the port side of an uncontrolled rectifier bridge as disclosed above are implemented.
The computer-readable storage medium provided by the embodiment of the invention has the beneficial effects of the method for detecting the fault of the port side of the uncontrolled rectifier bridge.
In the present specification, the embodiments are described in a progressive manner, and each embodiment focuses on differences from other embodiments, and the same or similar parts between the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The method, the device, the equipment and the medium for detecting the fault at the port side of the uncontrolled rectifier bridge provided by the invention are described in detail, a specific example is applied in the text to explain the principle and the implementation mode of the invention, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
Claims (9)
1. A method for detecting a fault on an uncontrolled rectifier bridge port side is characterized by comprising the following steps:
acquiring a line voltage measuring signal of an uncontrolled rectifier bridge, and constructing a six-pulse wave rectified voltage of a direct current output side of the uncontrolled rectifier bridge under a circuit breaking condition according to the line voltage measuring signal;
obtaining an estimated bus voltage of the direct current output side of the uncontrolled rectifier bridge according to the six-pulse wave rectified voltage;
respectively extracting the pulsation amplitude of the estimated bus voltage and the pulsation amplitude of the actually measured bus voltage under 300Hz to obtain a first pulsation amplitude and a second pulsation amplitude, and extracting the pulsation amplitude of the six-pulse rectification voltage under 100Hz to obtain a third pulsation amplitude;
determining whether the bus capacitor on the direct current output side of the uncontrolled rectifier bridge is aged or not according to the first pulsation amplitude and the second pulsation amplitude;
and acquiring a direct current component of the six-pulse wave rectified voltage, and determining whether the power grid voltage at the input side of the uncontrolled rectifier bridge has an unbalanced fault or not according to the direct current component and the third pulse amplitude.
2. The method for detecting faults according to claim 1, wherein the process of obtaining a line voltage measurement signal of the uncontrolled rectifier bridge and constructing a six-pulse wave rectified voltage of the direct current output side of the uncontrolled rectifier bridge in a circuit breaking situation according to the line voltage measurement signal comprises:
obtaining the line voltage measuring signal u of the uncontrolled rectifier bridge RS 、u ST And u TR And according to the first target model, the line voltage measuring signal u RS 、u ST And u TR Constructing the six-pulse wave rectification voltage of the direct current output side of the uncontrolled rectifier bridge under the condition of circuit breaking;
wherein the expression of the first target model is:
u rect ＝max(|u RS |,|u ST |,|u TR |)；
in the formula u rect Rectifying the voltage u for the six-pulse wave RS Is the voltage value between the R phase and the S phase on the uncontrolled rectifier bridge u ST Is the voltage value between S phase and T phase on the uncontrolled rectifier bridge u TR And the voltage value between the T phase and the R phase on the uncontrolled rectifier bridge is obtained.
3. The method according to claim 2, wherein the step of obtaining the estimated bus voltage at the dc output side of the uncontrolled rectifier bridge according to the six-pulse rectified voltage comprises:
acquiring the estimated bus voltage at the direct current output side of the uncontrolled rectifier bridge according to a second target model and the six-pulse wave rectified voltage;
wherein the expression of the second target model is:
in the formula (I), the compound is shown in the specification,
estimated bus voltage, u, at time t rect Rectifying the voltage, R, for said six-pulse wave dc And C dc Respectively an equivalent resistor and an equivalent capacitor at the direct current output side of the uncontrolled rectifier bridge.
4. The method according to claim 1, wherein the step of extracting the ripple amplitudes of the estimated bus voltage and the measured bus voltage at 300Hz respectively to obtain a first ripple amplitude and a second ripple amplitude comprises:
extracting a harmonic signal of the estimated bus voltage under 300Hz by using a second-order Butterworth filter to obtain a first harmonic signal, and performing absolute value operation and low-pass filtering on the first harmonic signal to obtain a first pulsation amplitude;
and extracting a harmonic signal of the actually measured bus voltage under 300Hz by using the second-order Butterworth filter to obtain a second harmonic signal, and performing absolute value operation and low-pass filtering on the second harmonic signal to obtain the second pulsation amplitude.
5. The method of claim 1, wherein the step of determining whether the bus capacitance on the dc output side of the uncontrolled rectifier bridge is degraded according to the first ripple amplitude and the second ripple amplitude comprises:
and if the first pulsation amplitude and the second pulsation amplitude meet a preset judgment condition, judging that the bus capacitor on the direct current output side of the uncontrolled rectifier bridge is aged.
6. The method according to any one of claims 1 to 5, wherein the step of determining whether the grid voltage at the input side of the uncontrolled rectifier bridge has an unbalanced fault according to the DC component and the third ripple amplitude comprises:
performing per-unit processing on the third pulsation amplitude value by taking the direct-current component as a reference value to obtain a target value;
and if the target value is greater than a preset threshold value and the duration of the target value greater than the preset threshold value is greater than a preset duration, judging that the power grid voltage on the input side of the uncontrolled rectifier bridge has an unbalanced fault.
7. A device for detecting a fault on the port side of an uncontrolled rectifier bridge, comprising:
the voltage construction module is used for obtaining a line voltage measuring signal of the uncontrolled rectifier bridge and constructing six-pulse wave rectification voltage of the direct current output side of the uncontrolled rectifier bridge under the condition of circuit breaking according to the line voltage measuring signal;
the voltage estimation module is used for acquiring the estimated bus voltage of the direct-current output side of the uncontrolled rectifier bridge according to the six-pulse wave rectified voltage;
the amplitude extraction module is used for respectively extracting the pulse amplitudes of the estimated bus voltage and the actually measured bus voltage under 300Hz to obtain a first pulse amplitude and a second pulse amplitude, and extracting the pulse amplitudes of the six-pulse rectification voltage under 100Hz to obtain a third pulse amplitude;
the first judging module is used for determining whether the bus capacitor on the direct current output side of the uncontrolled rectifier bridge is aged or not according to the first pulsation amplitude and the second pulsation amplitude;
and the second judgment module is used for acquiring the direct-current component of the six-pulse wave rectified voltage and determining whether the power grid voltage on the input side of the uncontrolled rectifier bridge has an unbalanced fault or not according to the direct-current component and the third pulse amplitude.
8. A device for detecting a fault on the port side of an uncontrolled rectifier bridge, comprising:
a memory for storing a computer program;
processor for implementing the steps of a method for fault detection on the port side of an uncontrolled rectifier bridge according to any of claims 1 to 6 when executing said computer program.
9. A computer-readable storage medium, characterized in that the computer-readable storage medium has stored thereon a computer program which, when being executed by a processor, carries out the steps of a method for uncontrolled bridge port side fault detection according to any of the claims 1 to 6.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210318877.XA CN114791573A (en) | 2022-03-29 | 2022-03-29 | Method, device, equipment and medium for detecting fault of uncontrolled rectifier bridge port side |
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| CN202210318877.XA CN114791573A (en) | 2022-03-29 | 2022-03-29 | Method, device, equipment and medium for detecting fault of uncontrolled rectifier bridge port side |
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