CN111751777A - A method for diagnosing the running state of a voltage transformer - Google Patents

Abstract

The invention relates to a method and a system for diagnosing the running state of a voltage transformer. The method comprises: periodically sampling the secondary voltage output by the voltage transformer to obtain sampled data; The voltage average value of B-phase and C-phase; calculate the voltage difference between each two phases according to the voltage average value of A-phase, B-phase and C-phase; according to the A-phase, B-phase and C-phase voltage average value and the voltage difference between each two phases to calculate the voltage deviation between each two phases; according to the comparison result of the voltage deviation between each two phases and the preset deviation threshold, and the preset judgment logic to determine the voltage Whether the transformer is faulty. The invention can prevent the situation that the electrical performance of the voltage transformer is normal during the power failure inspection, but the fault occurs during the operation during the actual operation process, and avoids affecting the safe and stable operation of the power equipment and the safety of electrical workers.

Description

A method for diagnosing the running state of a voltage transformer

technical field

The invention relates to the technical field of voltage transformers, in particular to a method for diagnosing the running state of a voltage transformer.

Background technique

In order to transmit electrical energy over long distances and with high power, the power system needs to use high voltage for transmission. The above-mentioned voltage level is much higher than the human safety voltage of 36V, and also higher than the 220V of the daily electricity consumption of residents. Power equipment that transmits high voltage levels needs to perform monitoring and control such as real-time status monitoring, energy metering, etc., and it is necessary to convert high voltage into low voltage. The function of the voltage transformer is to convert the high voltage proportionally into a standard secondary voltage of 100V or lower for use by protection, metering, and instrumentation devices, so that high-voltage equipment can be monitored, controlled and protected. At the same time, the use of voltage transformers can isolate high voltages from electrical workers to ensure personal safety. Inaccurate secondary voltage output from the voltage transformer will lead to the following problems: 1. Errors in electric energy measurement, resulting in economic losses and disputes; 2. Errors in power system regulation, resulting in power equipment operating at higher than rated voltage or lower than rated voltage 3. The relay protection equipment malfunctions, causing the user to lose power, or the relay protection equipment refuses to operate, resulting in the failure of the power equipment to be removed and isolated in time, resulting in damage to the power equipment. Therefore, the operating state of the voltage transformer will directly affect the safe and stable operation of power equipment and the safety of electrical workers.

At present, the detection of voltage transformer operating status is mainly based on regular power outage inspections in accordance with maintenance procedures, and the inspection period is more than 3 years. "Power Equipment Maintenance Test Regulations" Q/CSG1206007-2017 stipulates the maintenance test of capacitive voltage transformers: 110kV and below shall be tested every 6 years, and 110kV and above shall be tested every 3 years, and the deviation of the capacitance value of each section shall be specified. It does not exceed -5%—+10% of the rated value. Only when the capacitance measurement value deviates from the factory value or the last measurement value by more than 2%, can the accuracy be measured.

In the process of realizing the present invention, the inventor found that the current voltage transformer power failure inspection has the following problems:

Although some voltage transformer faults and hidden dangers can be found in the power outage inspection. However, the development of voltage transformer faults presents exponential characteristics, that is, the development of faults is not linear, but develops slowly at the beginning. When the fault accumulates to a certain extent, the electrical insulation and electromagnetic transmission of the voltage transformer will directly deteriorated and can no longer function properly. In the early stage of failure, the electrical performance of the voltage transformer does not change much. Even if the power is cut off, the problem cannot be found, but it may have deteriorated before the next inspection cycle. At the same time, in order to consider the test error during the power failure inspection, the inspection standards have a certain fault tolerance margin, and this margin is usually larger than the electrical performance error of the initial fault of the voltage transformer. That is to say, the existing means and methods for regular power failure inspection cannot detect the fault of the voltage transformer in time. In the actual operation process, there are many situations where the electrical performance of the voltage transformer is normal during the power outage inspection, and the fault occurs during operation.

SUMMARY OF THE INVENTION

The purpose of the present invention is to propose a method for diagnosing the running state of a voltage transformer, so as to solve the above-mentioned technical problem of the current power failure inspection of the voltage transformer.

To achieve the above purpose, an embodiment of the present invention proposes a method for diagnosing the operating state of a voltage transformer, including:

Periodically sample the secondary voltage output by the voltage transformer to obtain sampled data;

Calculate the average voltage of the A-phase, B-phase and C-phase according to the sampled data;

Calculate the voltage difference between each two phases according to the voltage average value of the A-phase, B-phase and C-phase;

Calculate the voltage deviation between each of the two phases according to the voltage average value of the A-phase, the B-phase and the C-phase and the voltage difference between the two phases;

Whether the voltage transformer is faulty is determined according to the comparison result between the voltage deviation between the two phases and the preset deviation threshold value and the preset judgment logic.

Preferably, the sampling data is one of daily sampling data, weekly sampling data, and monthly sampling data.

Preferably, the calculating the average voltage of the A-phase, B-phase and C-phase according to the sampled data specifically includes:

Calculate the daily average voltage of A-phase, B-phase and C-phase according to the daily sampling data;

Or, calculate the average value of the weekly voltage of phase A, phase B and phase C according to the weekly sampling data;

Alternatively, calculate the monthly average voltages of Phase A, Phase B, and Phase C based on monthly sampling data.

Preferably, the calculating the voltage difference between each two phases according to the average value of the voltages of the A-phase, B-phase and C-phase, specifically includes:

The voltage difference between each two phases is calculated according to the daily voltage average, the weekly voltage average or the monthly voltage average value of the A-phase, B-phase and C-phase.

Preferably, the calculating the voltage deviation between each two phases according to the average voltage of the A-phase, B-phase and C-phase and the voltage difference between the two phases, specifically includes:

为A、B相之间的电压偏差，

为B、C相之间的电压偏差，

为C、A相之间的电压偏差。Among them, U _A is the average voltage of phase A, U _B is the average voltage of phase B, U _C is the average voltage of phase C, _Δ U _AB is the voltage difference between phases A and B, and _Δ U _BC is The voltage difference between B and C phases, _Δ U _CA is the voltage difference between C and A phases,

is the voltage deviation between phases A and B,

is the voltage deviation between phases B and C,

is the voltage deviation between phases C and A.

Preferably, determining whether the voltage transformer is faulty according to the comparison result between the voltage deviation between the two phases and the preset deviation threshold value and the preset judgment logic specifically includes:

则A、B两相异常，C相正常；if only

Then the A and B phases are abnormal, and the C phase is normal;

则B、C两相异常，A相正常；if only

Then phase B and C are abnormal, and phase A is normal;

则A、C两相异常，B相正常；if only

Then phase A and C are abnormal, and phase B is normal;

且

则A相异常，B、C相正常；if

and

Phase A is abnormal, and phases B and C are normal;

且

则B相异常，A、C相正常；if

and

Phase B is abnormal, and phases A and C are normal;

且

则C相异常，A、B相正常；if

and

The C phase is abnormal, and the A and B phases are normal;

且

则A、B、C三相异常。if

and

Then the three phases of A, B, and C are abnormal.

Preferably, determining whether the voltage transformer is faulty according to the comparison result between the voltage deviation between the two phases and the preset deviation threshold value and the preset judgment logic specifically includes:

则A、B两相异常，C相正常；If there are multiple consecutive cycles, only

Then the A and B phases are abnormal, and the C phase is normal;

则B、C两相异常，A相正常；If there are multiple consecutive cycles, only

Then phase B and C are abnormal, and phase A is normal;

则A、C两相异常，B相正常；If there are multiple consecutive cycles, only

Then phase A and C are abnormal, and phase B is normal;

且

则A相异常，B、C相正常；If there are multiple consecutive cycles,

and

Phase A is abnormal, and phases B and C are normal;

且

则B相异常，A、C相正常；If there are multiple consecutive cycles,

and

Phase B is abnormal, and phases A and C are normal;

且

则C相异常，A、B相正常；If there are multiple consecutive cycles,

and

The C phase is abnormal, and the A and B phases are normal;

且

则A、B、C三相异常。If there are multiple consecutive cycles,

and

Then the three phases of A, B, and C are abnormal.

Preferably, the method further includes:

If it is determined that the voltage transformer is faulty according to the comparison result between the voltage deviation between each two phases and the preset deviation threshold and the preset decision logic, alarm information corresponding to the fault type is output, and the alarm information is stored.

In a second aspect, an embodiment of the present invention provides a system for diagnosing an operating state of a voltage transformer, which is used to implement the method of the foregoing embodiment, including:

The sampling unit is used to periodically sample the secondary voltage output by the voltage transformer to obtain sampling data;

an average value calculation unit, used for calculating the voltage average value of A-phase, B-phase and C-phase according to the sampled data;

a voltage difference calculation unit, configured to calculate the voltage difference between each two phases according to the average voltage of the A-phase, B-phase and C-phase;

a voltage deviation calculation unit, configured to calculate the voltage deviation between every two phases according to the voltage average value of the A-phase, the B-phase and the C-phase and the voltage difference between the two phases; and

The fault determination unit is configured to determine whether the voltage transformer is faulty according to the comparison result between the voltage deviation between the two phases and the preset deviation threshold value and the preset judgment logic.

Preferably, the system further includes:

an alarm unit, configured to output an alarm corresponding to the fault type if the fault determination unit determines that the voltage transformer is faulty according to the comparison result of the voltage deviation between the two phases and the preset deviation threshold value and the preset judgment logic information, and store the alarm information.

The above embodiment scheme has the following beneficial effects:

By periodically sampling the secondary voltage output by the voltage transformer to obtain sampling data, which can be daily sampling data, weekly sampling data or monthly sampling data, and calculating the voltage deviation between each two phases according to the sampling data , and finally determine whether the voltage transformer is faulty according to the comparison result between the voltage deviation between the two phases and a preset deviation threshold value and the preset judgment logic. Among them, the sampling of the secondary voltage output by the voltage transformer can be carried out without power failure, so as to realize the sampling and carry out the operation status diagnosis of the voltage transformer according to the sampled data, so as to prevent the voltage transformer electrical failure during the power failure inspection during the actual operation. The performance is normal, but the failure occurs during operation, so as to avoid affecting the safe and stable operation of power equipment and the safety of electrical workers.

Other features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or will be manifested by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the description, claims and drawings.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

FIG. 1 is a flowchart of a method for diagnosing an operating state of a voltage transformer according to an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of a capacitive voltage transformer in an embodiment of the present invention.

FIG. 3 is a frame diagram of a system for diagnosing an operating state of a voltage transformer according to an embodiment of the present invention.

Detailed ways

Various exemplary embodiments, features and aspects of the present invention will be described in detail below with reference to the accompanying drawings. The same reference numbers in the figures denote elements that have the same or similar functions. While various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

In addition, in order to better illustrate the present invention, numerous specific details are given in the following specific embodiments. It will be understood by those skilled in the art that the present invention may be practiced without certain specific details. In some instances, means well known to those skilled in the art have not been described in detail in order not to obscure the subject matter of the present invention.

As shown in FIG. 1 , an embodiment of the present invention provides a method for diagnosing an operating state of a voltage transformer, including:

Step S1, periodically sampling the secondary voltage output by the voltage transformer to obtain sampling data;

Step S2, calculate the voltage average value of A-phase, B-phase and C-phase according to the sampling data;

Step S3, calculating the voltage difference between each two phases according to the voltage average value of the A-phase, B-phase and C-phase;

Step S4, calculating the voltage deviation between each two phases according to the voltage average value of the A-phase, the B-phase and the C-phase and the voltage difference between the two phases;

Step S5: Determine whether the voltage transformer is faulty according to the comparison result between the voltage deviation between the two phases and the preset deviation threshold value and the preset judgment logic.

Specifically, the capacitive voltage transformer (CVT) is divided by a series capacitor, and then stepped down and isolated by an electromagnetic transformer, as a voltage transformer for meters, relay protection, etc. Compared with the electromagnetic voltage transformer, the capacitive voltage transformer can not only prevent the ferromagnetic resonance caused by the saturation of the iron core of the voltage transformer, but also has the advantages of high impact dielectric strength, simple manufacture, light weight, small size, low cost and operation. It is reliable, easy to maintain and can also be used as a coupling capacitor for high-frequency carrier communication. The main disadvantage is that its error characteristics are worse than that of electromagnetic voltage transformers, and the output capacity is small, and there are many factors that affect the error (such as temperature, frequency, etc.). At present, the accuracy of TYD-type capacitive voltage transformers manufactured in my country has been improved to 0.5 level, and it has been widely used in 110kV and above neutral point direct grounding systems.

Capacitive voltage transformers are mainly composed of capacitive voltage dividers and intermediate transformers. The capacitor voltage divider is composed of a porcelain sleeve and several series capacitors installed in it, and the porcelain sleeve is filled with insulating oil. The medium voltage transformer consists of a transformer, a compensation reactor, a surge arrester and a damping device installed in a sealed oil tank. Capacitive voltage transformer is essentially a capacitive voltage divider. In order to facilitate analysis, the capacitor string is divided into two parts: main capacitor C1 and voltage divider capacitor C2 (also called upper capacitor C1 and lower capacitor C2). Several capacitors are connected in series, as shown in Figure 2. T is the intermediate transformer, L is the compensating reactor, and BL is the protective arrester connected in parallel at both ends of the compensating reactor. Both the intermediate transformer T and the compensation reactor L are provided with taps, which are respectively used to adjust the amplitude error and phase error of the capacitive voltage transformer. 1a, 1n are the first set of secondary windings, mainly used for measurement; 2a, 2n are the second set of secondary windings, mainly used for protection; da, dn are the third set of secondary windings, and the third set of the other two phases The secondary windings are connected in series to measure the zero-sequence voltage. A fast saturation damper Z composed of reactance and resistance is also connected in parallel at both ends of the third winding. This is mainly because the nonlinear impedance and inherent capacitance of the capacitive voltage transformer sometimes cause iron in the capacitive voltage transformer. Magnetic resonance, thus damping the resonance with a damping device. Under normal circumstances, the damping device has a high impedance. When the ferromagnetic resonance causes overvoltage, before the intermediate transformer is affected, the reactor has been saturated and only the resistance load is left, so that the oscillation energy is quickly reduced.

Assuming that the voltage at the upper end of the capacitive voltage transformer is U, and the voltage at the primary side of the intermediate transformer is U', then:

U’=U×C1/(C1+C2)

In the formula, K=C1/(C1+C2) is the voltage division ratio. By changing the ratio of C1 and C2, different voltage division ratios can be obtained. When part of C1 is damaged, C1 will become larger and the voltage on the primary side of the intermediate transformer will increase; when part of C2 is damaged, C2 will become larger and the voltage on the primary side of the intermediate transformer will decrease. Therefore, the corresponding secondary side voltage will also change, and the magnitude of the change is closely related to C1 and C2.

Through the above analysis of the principle of the capacitive voltage transformer, it can be known that when the upper and lower capacitors of the capacitive voltage transformer have breakdown faults, intermediate transformer faults and secondary circuit faults, they can all affect the output secondary voltage. The function of the voltage transformer is to convert the primary voltage into a qualified secondary voltage. Therefore, the present application judges the operation state of the voltage transformer by monitoring the voltage on the secondary side, and judges whether there is a fault.

The sampling data is one of daily sampling data, weekly sampling data, monthly sampling data or annual sampling data.

Specifically, the secondary voltage of the voltage transformer also changes with the voltage of the primary system, and the change of the voltage of the primary system also has a certain randomness. Therefore, the reference standard selected for monitoring the secondary side voltage cannot be the rated voltage of the voltage transformer. At the same time, the primary system load also fluctuates with time, so the historical value cannot be simply selected as the reference standard. Because the power systems are all three-phase running at the same time, and the three-phase voltage transformers are basically the same manufacturer and put into operation at the same time. Therefore, the normal decay period of the three-phase voltage transformer is also the same. Although the load of the primary system fluctuates all the time, the three phases are roughly balanced for a long time. Therefore, the present application selects the daily history curve, weekly history curve, monthly history curve or year history curve of the three-phase voltage transformers of the same bus or interval as the basis for judging the operating state of the voltage transformers.

In step S1, a sampling period is set, for example, a secondary voltage value is collected every 5 minutes, the three-phase voltages are U _A1 , U _B1 , and U _C1 respectively, and the three-phase voltages in the next sampling period are U _A2 , U respectively _B2 , U _C2 , and so on, send all the sampled values to the memory for storage. The secondary voltage value of the three-phase voltage every day is the average value of all the voltages on that day, namely:

In the formula, U _At , U _Bt , and U _Ct , respectively, are the average voltage of the three-phase voltage per equivalent day, representing the voltage value of the day. Replacing the instantaneous sampling value with the average value can reduce the influence of factors such as sampling error and power system voltage fluctuation on the secondary voltage. U _Ai , U _Bi , and U _Ci represent the instantaneous sampling values of the three-phase voltage at each sampling time point of the day, that is, the instantaneous value of the three-phase voltage at a certain moment. n is the total number of voltage sampling points on the day, and the value can be calculated by the preset sampling period. For example, if the sampling period is 1 hour, n=24.

Wherein, the step S2 specifically includes:

Calculate the daily average voltage of A-phase, B-phase and C-phase according to the daily sampling data;

Or, calculate the average value of the weekly voltage of phase A, phase B and phase C according to the weekly sampling data;

Alternatively, calculate the monthly average voltages of Phase A, Phase B, and Phase C based on monthly sampling data.

Specifically, calculate the daily three-phase voltage value according to the above steps, and then use the daily voltage value to calculate the weekly voltage value. The calculation method of the weekly voltage value is the same as the daily voltage value. The voltages are averaged individually, namely:

In the formula, U _Az , U _Bz , U _Cz , respectively, are the average value of the three-phase voltage per equivalent cycle voltage, representing the current cycle voltage value. Replacing the instantaneous sampling value with the average value can reduce the influence of factors such as sampling error and power system voltage fluctuation on the secondary voltage. U _Ati , U _Bti , U _Cti represent the average voltage of the three-phase voltage on that day. n is the total number of voltage sampling points in the current week, the value n=7.

According to the above steps, and so on, the monthly and annual voltage values of the three-phase voltage can be obtained.

Wherein, the step S3 specifically includes:

The voltage difference between each two phases is calculated according to the daily voltage average, the weekly voltage average or the monthly voltage average value of the A-phase, B-phase and C-phase.

Specifically, the daily voltage value, weekly voltage value, monthly voltage value, and annual voltage value of the three-phase voltage are obtained through the above sampling and calculation methods. voltage difference. which is:

ΔU _AB =U _A -U _B

ΔU _BC =U _B -U _C

ΔU _CA =U _C -U _A

When different voltages are used, different voltage differences can be calculated. For example, when daily voltage values are used, daily voltage differences can be calculated, and weekly voltage differences can be calculated when weekly voltage values are used.

Wherein, the step S4 specifically includes:

为A、B相之间的电压偏差，

为B、C相之间的电压偏差，

为C、A相之间的电压偏差。Among them, U _A is the average voltage of phase A, U _B is the average voltage of phase B, U _C is the average voltage of phase C, _Δ U _AB is the voltage difference between phases A and B, and _Δ U _BC is The voltage difference between B and C phases, _Δ U _CA is the voltage difference between C and A phases,

is the voltage deviation between phases A and B,

is the voltage deviation between phases B and C,

is the voltage deviation between phases C and A.

Wherein, in one embodiment, the step S5 specifically includes:

则A、B两相异常，C相正常；if only

Then the A and B phases are abnormal, and the C phase is normal;

则B、C两相异常，A相正常；if only

Then phase B and C are abnormal, and phase A is normal;

则A、C两相异常，B相正常；if only

Then phase A and C are abnormal, and phase B is normal;

且

则A相异常，B、C相正常；if

and

Phase A is abnormal, and phases B and C are normal;

且

则B相异常，A、C相正常；if

and

Phase B is abnormal, and phases A and C are normal;

且

则C相异常，A、B相正常；if

and

The C phase is abnormal, and the A and B phases are normal;

且

则A、B、C三相异常。if

and

Then the three phases of A, B, and C are abnormal.

或

时判断出电压互感器二次电压存在异常。其中

为给定的电压偏差标准，该值随计算不同时间长度、不同电压等级的二次电压时不一样。例如在计算500kV电压互感器周电压偏差时

而计算500kV电压互感器月电压偏差时

Specifically, the calculated voltage deviation of each phase is compared with the given voltage deviation standard. When the calculated voltage deviation is greater than the given voltage deviation standard, it is judged that the secondary voltage of the voltage transformer is abnormal, that is,

or

When it is judged that the secondary voltage of the voltage transformer is abnormal. in

For a given voltage deviation standard, this value is different when calculating the secondary voltage of different time lengths and different voltage levels. For example, when calculating the cycle voltage deviation of a 500kV voltage transformer

When calculating the monthly voltage deviation of 500kV voltage transformer

则判断为A、B两相电压互感器异常。当三个电压偏差中，有两个电压偏差大于电压偏差标准时，则上述两个电压偏差所共同涉及相的电压互感器异常，即当只有

则判断为B两相电压互感器异常。It can be understood that when only one of the three voltage deviations is greater than the voltage deviation standard, it is judged that the two-phase voltage transformer involved in the voltage deviation is abnormal, that is, when only

Then it is judged that the two-phase voltage transformers of A and B are abnormal. When two of the three voltage deviations are greater than the voltage deviation standard, the voltage transformers of the phases commonly involved in the above two voltage deviations are abnormal, that is, when only

Then it is judged that the two-phase voltage transformer of B is abnormal.

Wherein, in another embodiment, the step S5 specifically includes:

则A、B两相异常，C相正常；If there are multiple consecutive cycles, only

Then the A and B phases are abnormal, and the C phase is normal;

则B、C两相异常，A相正常；If there are multiple consecutive cycles, only

Then phase B and C are abnormal, and phase A is normal;

则A、C两相异常，B相正常；If there are multiple consecutive cycles, only

Then phase A and C are abnormal, and phase B is normal;

且

则A相异常，B、C相正常；If there are multiple consecutive cycles,

and

Phase A is abnormal, and phases B and C are normal;

且

则B相异常，A、C相正常；If there are multiple consecutive cycles,

and

Phase B is abnormal, and phases A and C are normal;

且

则C相异常，A、B相正常；If there are multiple consecutive cycles,

and

The C phase is abnormal, and the A and B phases are normal;

且

则A、B、C三相异常。If there are multiple consecutive cycles,

and

Then the three phases of A, B, and C are abnormal.

Specifically, in this embodiment, in order to eliminate the interference of accidental factors, resulting in the occurrence of misjudgment, the voltage deviation comparison of multiple consecutive cycles can be used to judge, that is, the voltage deviation can be set to exceed the voltage in a certain cycle of 3 consecutive cycles. The deviation standard, the voltage deviation of a certain month for 2 consecutive months exceeds the voltage deviation standard, and the fault is determined.

In a specific embodiment, the method further includes:

If it is determined that the voltage transformer is faulty according to the comparison result between the voltage deviation between each two phases and the preset deviation threshold and the preset decision logic, alarm information corresponding to the fault type is output, and the alarm information is stored.

It can be understood that, in the above embodiment, due to the current detection methods and detection cycle limitations of voltage transformers, abnormality or even failure of voltage transformers cannot be found in time, and voltage transformers are very important electrical equipment in the power system. Safe and stable operation is related to the normal operation of the power system and electrical equipment. By monitoring the secondary output voltage of the voltage transformer in real time, and calculating the voltage difference and voltage deviation in different periods, the abnormality of the voltage transformer can be detected in time and reminded. Electrical operation and maintenance personnel deal with it in time to avoid major power accidents.

As can be seen from the description of the above embodiments, the present invention has the following advantages:

(1) The method can discriminate the operating state of the voltage transformer according to the secondary output voltage of the voltage transformer, can monitor in real time, and detect and give an alarm immediately after the abnormality of the voltage transformer occurs.

(2) This method can be widely used in various situations where three-phase voltage transformers are installed.

(3) This method does not require power outage of substation equipment when solving the problem of abnormal upper voltage transformers and failure to calculate when faults are found, which greatly reduces the difficulty of rectification and reduces the cost of rectification.

As shown in FIG. 3 , an embodiment of the present invention provides a system for diagnosing an operating state of a voltage transformer, which is used to implement the method of the foregoing embodiment, including:

The sampling unit 1 is used for periodically sampling the secondary voltage output by the voltage transformer to obtain sampling data;

an average value calculation unit 2, configured to calculate the voltage average value of A-phase, B-phase and C-phase according to the sampled data;

a voltage difference calculation unit 3, configured to calculate the voltage difference between each two phases according to the voltage average value of the A-phase, B-phase and C-phase;

a voltage deviation calculation unit 4, configured to calculate the voltage deviation between every two phases according to the voltage average value of the A-phase, the B-phase and the C-phase and the voltage difference between the two phases; and

The fault determination unit 5 is configured to determine whether the voltage transformer is faulty according to the comparison result between the voltage deviation between the two phases and the preset deviation threshold value and the preset judgment logic.

In a specific embodiment, the system further includes:

The alarm unit 6 is used for if the fault determination unit 5 determines that the voltage transformer is faulty according to the comparison result of the voltage deviation between the two phases and the preset deviation threshold and the preset determination logic, the alarm unit 6 outputs and The alarm information corresponding to the fault type is stored, and the alarm information is stored.

The system embodiments described above are only illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in One place, or it can be distributed over multiple network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution in this embodiment.

It should be noted that the system described in the foregoing embodiment corresponds to the method described in the foregoing embodiment. Therefore, the undescribed part of the system described in the foregoing embodiment can be obtained by referring to the content of the method described in the foregoing embodiment, which will not be repeated here.

Moreover, if the parking space line identification system described in the above embodiments is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium.

Specifically, the computer-readable storage medium may include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a removable hard disk, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium, etc.

Various embodiments of the present invention have been described above, and the foregoing descriptions are exemplary, not exhaustive, and not limiting of the disclosed embodiments. Numerous modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims (10)

1. A method for diagnosing the operating state of a voltage transformer, comprising: Periodically sample the secondary voltage output by the voltage transformer to obtain sampled data; Calculate the average voltage of the A-phase, B-phase and C-phase according to the sampled data; Calculate the voltage difference between each two phases according to the voltage average value of the A-phase, B-phase and C-phase; Calculate the voltage deviation between each of the two phases according to the voltage average value of the A-phase, the B-phase and the C-phase and the voltage difference between the two phases; Whether the voltage transformer is faulty is determined according to the comparison result of the voltage deviation between the two phases and the preset deviation threshold value and the preset judgment logic. 2 . The method for diagnosing the operating state of a voltage transformer according to claim 1 , wherein the sampling data is one of daily sampling data, weekly sampling data, and monthly sampling data. 3 . 3. The method for diagnosing the operating state of a voltage transformer according to claim 2, wherein the calculating the average voltage of the A-phase, the B-phase and the C-phase according to the sampled data specifically comprises: Calculate the daily average voltage of A-phase, B-phase and C-phase according to the daily sampling data; Or, calculate the average value of the weekly voltage of phase A, phase B and phase C according to the weekly sampling data; Alternatively, calculate the monthly average voltages of Phase A, Phase B, and Phase C based on monthly sampling data. 4. The method for diagnosing the operating state of a voltage transformer according to claim 3, wherein the voltage difference between each two phases is calculated according to the average value of the voltages of the A-phase, B-phase and C-phase, and the specific include: The voltage difference between each two phases is calculated according to the daily voltage average, the weekly voltage average or the monthly voltage average value of the A-phase, B-phase and C-phase. 5 . The method for diagnosing the operating state of a voltage transformer according to claim 4 , wherein the method is based on the average value of the voltages of the A-phase, the B-phase and the C-phase and the voltage difference between the two phases. 6 . Calculate the voltage deviation between each two phases, including:

Among them, U _A is the average voltage of phase A, U _B is the average voltage of phase B, U _C is the average voltage of phase C, ΔU _AB is the voltage difference between phases A and B, and ΔU _BC is the average voltage of phase B, The voltage difference between phases C, ΔU _CA is the voltage difference between phases C and A,

is the voltage deviation between phases A and B,

is the voltage deviation between phases B and C,

is the voltage deviation between phases C and A. 6 . The method for diagnosing the operating state of a voltage transformer according to claim 5 , wherein the voltage is determined according to a comparison result between the voltage deviation between each two phases and a preset deviation threshold, and a preset judgment logic. 7 . Whether the transformer is faulty, including: if only

Then the A and B phases are abnormal, and the C phase is normal; if only

Then phase B and C are abnormal, and phase A is normal; if only

Then phase A and C are abnormal, and phase B is normal; if

and

Phase A is abnormal, and phases B and C are normal; if

and

Phase B is abnormal, and phases A and C are normal; if

and

The C phase is abnormal, and the A and B phases are normal; if

and

Then the three phases of A, B, and C are abnormal. 7 . The method for diagnosing the operating state of a voltage transformer according to claim 6 , wherein the voltage is determined according to a comparison result between the voltage deviation between each two phases and a preset deviation threshold, and a preset judgment logic. 8 . Whether the transformer is faulty, including: If there are multiple consecutive cycles, only

Then the A and B phases are abnormal, and the C phase is normal; If there are multiple consecutive cycles, only

Then phase B and C are abnormal, and phase A is normal; If there are multiple consecutive cycles, only

Then phase A and C are abnormal, and phase B is normal; If there are multiple consecutive cycles,

and

Phase A is abnormal, and phases B and C are normal; If there are multiple consecutive cycles,

and

Phase B is abnormal, and phases A and C are normal; If there are multiple consecutive cycles,

and

The C phase is abnormal, and the A and B phases are normal; If there are multiple consecutive cycles,

and

Then the three phases of A, B, and C are abnormal. 8. The method for diagnosing the operating state of a voltage transformer according to claim 5, wherein the method further comprises: If it is determined that the voltage transformer is faulty according to the comparison result between the voltage deviation between each two phases and the preset deviation threshold and the preset decision logic, alarm information corresponding to the fault type is output, and the alarm information is stored. 9. A system for diagnosing the operating state of a voltage transformer, for implementing the method according to any one of claims 1-7, characterized in that, comprising: The sampling unit is used to periodically sample the secondary voltage output by the voltage transformer to obtain sampling data; an average value calculation unit, used for calculating the voltage average value of A-phase, B-phase and C-phase according to the sampled data; a voltage difference calculation unit, configured to calculate the voltage difference between each two phases according to the average voltage of the A-phase, B-phase and C-phase; a voltage deviation calculation unit, configured to calculate the voltage deviation between every two phases according to the voltage average value of the A-phase, the B-phase and the C-phase and the voltage difference between the two phases; and The fault determination unit is configured to determine whether the voltage transformer is faulty according to the comparison result between the voltage deviation between the two phases and the preset deviation threshold value and the preset judgment logic. 10. The system for diagnosing the operating state of a voltage transformer according to claim 9, wherein the system further comprises: an alarm unit, configured to output an alarm corresponding to the fault type if the fault determination unit determines that the voltage transformer is faulty according to the comparison result of the voltage deviation between the two phases and the preset deviation threshold value and the preset judgment logic information, and store the alarm information.

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