Voltage transformer operation state diagnosis method
阅读说明：本技术 一种电压互感器运行状态诊断方法 (Voltage transformer operation state diagnosis method ) 是由 谷斌 江晨玲 代尚林 梁嘉俊 刘华烨 郭乐欣 黄潇恺 樊新启 赖天德 王世祥 于 2020-06-29 设计创作，主要内容包括：本发明涉及一种电压互感器运行状态诊断方法及其系统,所述方法包括：周期性地对电压互感器输出的二次电压进行采样,以获得采样数据；根据所述采样数据计算A相、B相和C相的电压平均值；根据所述A相、B相和C相的电压平均值计算每两相之间的电压差值；根据所述A相、B相和C相的电压平均值以及所述每两相之间的电压差值计算每两相之间的电压偏差；根据所述每两相之间的电压偏差与预设偏差阈值的比较结果、以及预设判定逻辑判定电压互感器是否故障。本发明能够防止实际运行过程中,出现停电检查时电压互感器电气性能正常,运行中却发生故障的情况,避免影响电力设备安全稳定运行及电气工作人员安全。(The invention relates to a method and a system for diagnosing the operating state of a voltage transformer, wherein the method comprises the following steps: periodically sampling secondary voltage output by the voltage transformer to obtain sampling data; calculating the average voltage values of the A phase, the B phase and the C phase according to the sampling data; calculating the voltage difference value between each two phases according to the average voltage values of the A phase, the B phase and the C phase; calculating voltage deviation between each two phases according to the average voltage values of the A phase, the B phase and the C phase and the voltage difference value between each two phases; and judging whether the voltage transformer fails according to the comparison result of the voltage deviation between each two phases and a preset deviation threshold value and preset judgment logic. The invention can prevent the conditions that the electrical performance of the voltage transformer is normal and the voltage transformer breaks down in operation during power failure inspection in the actual operation process, and avoids influencing the safe and stable operation of power equipment and the safety of electrical workers.)
1. A method for diagnosing the operating state of a voltage transformer is characterized by comprising the following steps:
periodically sampling secondary voltage output by the voltage transformer to obtain sampling data;
calculating the average voltage values of the A phase, the B phase and the C phase according to the sampling data;
calculating the voltage difference value between each two phases according to the average voltage values of the A phase, the B phase and the C phase;
calculating voltage deviation between each two phases according to the average voltage values of the A phase, the B phase and the C phase and the voltage difference value between each two phases;
and judging whether the voltage transformer fails according to the comparison result of the voltage deviation between each two phases and a preset deviation threshold value and preset judgment logic.
2. The method for diagnosing an operating condition 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. The method for diagnosing the operating state of the voltage transformer according to claim 2, wherein the calculating of the average voltage values of the a-phase, the B-phase and the C-phase according to the sampling data specifically comprises:
calculating daily voltage average values of the A phase, the B phase and the C phase according to daily sampling data;
or, calculating the cycle voltage average value of the A phase, the B phase and the C phase according to the cycle sampling data;
alternatively, the average value of the monthly voltages of the A-phase, the B-phase and the C-phase is calculated from the monthly sampling data.
4. The method for diagnosing an operating condition of a voltage transformer according to claim 3, wherein the calculating a voltage difference value between each two phases based on the average values of the voltages of the A, B and C phases comprises:
and calculating the voltage difference value between each two phases according to the daily voltage average value, the weekly voltage average value or the monthly voltage average value of the phase A, the phase B and the phase C.
5. The method for diagnosing an operating condition of a voltage transformer according to claim 4, wherein the calculating of the voltage deviation between each two phases based on the average values of the voltages of the A, B and C phases and the voltage difference between each two phases comprises:
wherein, UAIs the average voltage value of phase A, UBIs the average voltage value of phase B, UCIs the average voltage value of the C phase, Δ UABIs the voltage difference between A, B phases, Δ UBCIs the voltage difference between B, C phases, Δ UCAIs the voltage difference between the C, A phases,
6. The method for diagnosing the operating status of the voltage transformer according to claim 5, wherein the determining whether the voltage transformer is faulty according to the comparison result of the voltage deviation between each two phases and a preset deviation threshold and a preset determination logic specifically comprises:
if only haveA, B two phases are abnormal, and phase C is normal;
if only haveB, C two phases are abnormal, phase A is normal;
if only have
if it is not
if it is notAnd is
if it is not
if it is notAnd isA, B, C three phases are abnormal.
7. The method for diagnosing the operating status of the voltage transformer according to claim 6, wherein the determining whether the voltage transformer is faulty according to the comparison result of the voltage deviation between each two phases and a preset deviation threshold and a preset determination logic specifically comprises:
if a plurality of cycles are continued, only
if a plurality of cycles are continued, onlyB, C two phases are abnormal, phase A is normal;
if a plurality of cycles are continued, only
if there are a plurality of cycles in succession,and isThen phase A is abnormal, and phase B, C is normal;
if there are a plurality of cycles in succession,and isThen phase B is abnormal, and phase A, C is normal;
if there are a plurality of cycles in succession,and is
if there are a plurality of cycles in succession,and isA, B, C three phases are abnormal.
8. The voltage transformer operating condition diagnostic method according to claim 5, characterized in that the method further comprises:
and if the voltage transformer fault is judged according to the comparison result of the voltage deviation between each two phases and a preset deviation threshold value and a preset judgment logic, outputting alarm information corresponding to the fault type, and storing the alarm information.
9. A voltage transformer operating condition diagnostic system for implementing the method of any one of claims 1-7, comprising:
the sampling unit is used for periodically sampling the secondary voltage output by the voltage transformer so as to obtain sampling data;
the average value calculating unit is used for calculating the average value of the voltage of the A phase, the B phase and the C phase according to the sampling data;
the voltage difference value calculating unit is used for calculating the voltage difference value between each two phases according to the average voltage values of the A phase, the B phase and the C phase;
the voltage deviation calculation unit is used for calculating the voltage deviation between each two phases according to the average voltage values of the A phase, the B phase and the C phase and the voltage difference value between each two phases; and
and the fault judging unit is used for judging whether the voltage transformer has faults or not according to the comparison result of the voltage deviation between each two phases and a preset deviation threshold value and preset judging logic.
10. The system for diagnosing an operational status of a voltage transformer according to claim 9, further comprising:
and the alarm unit is used for outputting alarm information corresponding to the fault type and storing the alarm information if the fault judgment unit judges the fault of the voltage transformer according to the comparison result of the voltage deviation between each two phases and a preset deviation threshold value and a preset judgment logic.
Technical Field
The invention relates to the technical field of voltage transformers, in particular to a method for diagnosing the operating state of a voltage transformer.
Background
In order to transmit electric energy in a long distance and high power, a power system needs to adopt high voltage to transmit the electric energy, and the voltage class of the transmitted electric energy is 10kV, 110kV, 220kV, 500kV or even 1000 kV. The voltage level is far higher than the human body safety voltage of 36V and is also higher than 220V of daily electricity consumption of residents. The power equipment transmitting high voltage level needs to be monitored and controlled in real time, such as state monitoring and electric energy metering, and high voltage needs to be converted into low voltage. The voltage transformer is used for converting high voltage into standard secondary voltage of 100V or lower level according to proportion relation for protection, metering and instrument devices to take, thus monitoring, controlling and protecting high voltage level equipment. Meanwhile, the voltage transformer can isolate high voltage from electrical workers, and personal safety of the workers is guaranteed. The inaccuracy of the secondary voltage output by the voltage transformer leads to the following problems: 1. the electric energy metering is wrong, so that economic loss and dispute are caused; 2. the power system is regulated and controlled wrongly, so that the power equipment operates at a voltage higher than or lower than the rated voltage, and the power equipment is damaged or has low efficiency; 3. the power equipment is damaged because a user has power failure due to misoperation of the relay protection equipment or the isolation cannot be cut off in time after the power equipment fails due to failure of the relay protection equipment. Therefore, the safety and the stability of the operation state of the voltage transformer directly influence the safe and stable operation of the power equipment and the safety of the electrical working personnel.
At present, the running state detection of the voltage transformer mainly comprises regular power failure detection according to maintenance regulations, and the detection period is more than 3 years. The overhaul test regulations of the capacitor voltage transformer in electric power equipment Q/CSG1206007-2017 specify: the detection is performed every 6 years at 110kV or less, every 3 years at 110kV or more, and each capacitance value deviation is specified not to exceed-5% -plus 10% of the rated value, and the precision measurement is performed only when the capacitance measurement value deviates more than 2% from the factory value or the last measurement value.
In the process of implementing the invention, the inventor finds that the following problems exist in the current voltage transformer power failure detection:
although partial voltage transformer faults and hidden dangers can be found in the power failure inspection. However, the development of the voltage transformer fault presents an exponential characteristic, that is, the development of the fault is not linear, but is slow at first, and when the fault is accumulated to a certain degree, the electrical insulation and the electromagnetic transmission of the voltage transformer are directly deteriorated after exceeding a critical point, so that the voltage transformer can not normally operate. The voltage transformer does not change much in electrical performance at the initial stage of a fault, and even if the voltage transformer is inspected in a power failure, the problem cannot be found, but the voltage transformer may be deteriorated before the next inspection period. Meanwhile, in order to consider the test error in the power failure inspection, the inspection standards have certain fault tolerance margin, and the margin is usually larger than the initial fault electrical performance error of the voltage transformer. That is, the existing means and method for checking the periodic power failure cannot find the fault of the voltage transformer in time. In the actual operation process, the electric performance of the voltage transformer is normal when a plurality of power failure checks occur, and a fault condition occurs in the operation.
Disclosure of Invention
The invention aims to provide a voltage transformer operation state diagnosis method to solve the technical problem of the current voltage transformer power failure detection.
In order to achieve the above object, an embodiment of the present invention provides a method for diagnosing an operating state of a voltage transformer, including:
periodically sampling secondary voltage output by the voltage transformer to obtain sampling data;
calculating the average voltage values of the A phase, the B phase and the C phase according to the sampling data;
calculating the voltage difference value between each two phases according to the average voltage values of the A phase, the B phase and the C phase;
calculating voltage deviation between each two phases according to the average voltage values of the A phase, the B phase and the C phase and the voltage difference value between each two phases;
and judging whether the voltage transformer fails according to the comparison result of the voltage deviation between each two phases and a preset deviation threshold value and 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 values of the a phase, the B phase and the C phase according to the sampling data specifically includes:
calculating daily voltage average values of the A phase, the B phase and the C phase according to daily sampling data;
or, calculating the cycle voltage average value of the A phase, the B phase and the C phase according to the cycle sampling data;
alternatively, the average value of the monthly voltages of the A-phase, the B-phase and the C-phase is calculated from the monthly sampling data.
Preferably, the calculating a voltage difference value between each two phases according to the average voltage value of the a phase, the B phase and the C phase specifically includes:
and calculating the voltage difference value between each two phases according to the daily voltage average value, the weekly voltage average value or the monthly voltage average value of the phase A, the phase B and the phase C.
Preferably, the calculating a voltage deviation between each two phases according to the average voltage values of the a, B and C phases and the voltage difference between each two phases specifically includes:
wherein, UAIs the average voltage value of phase A, UBIs the average voltage value of phase B, UCIs the average value of the voltage of the C phase,ΔUABis the voltage difference between the A, B phases,ΔUBCis the voltage difference between the B, C phases,ΔUCAis the voltage difference between the C, A phases,
Preferably, the determining whether the voltage transformer fails according to the comparison result between the voltage deviation between each two phases and a preset deviation threshold and a preset determination logic specifically includes:
if only haveA, B two phases are abnormal, and phase C is normal;
if only have
if only have
if it is not
if it is notAnd isThen phase B is abnormal, and phase A, C is normal;
if it is not
if it is notAnd isA, B, C three phases are abnormal.
Preferably, the determining whether the voltage transformer fails according to the comparison result between the voltage deviation between each two phases and a preset deviation threshold and a preset determination logic specifically includes:
if a plurality of cycles are continued, only
if a plurality of cycles are continued, only
if a plurality of cycles are continued, only
if there are a plurality of cycles in succession,
if there are a plurality of cycles in succession,
if there are a plurality of cycles in succession,and isThen phase C is abnormal, and phase A, B is normal;
if there are a plurality of cycles in succession,
Preferably, the method further comprises:
and if the voltage transformer fault is judged according to the comparison result of the voltage deviation between each two phases and a preset deviation threshold value and a preset judgment logic, outputting alarm information corresponding to the fault type, and storing the alarm information.
In a second aspect, an embodiment of the present invention provides a voltage transformer operating state diagnostic system, configured to implement the method in the foregoing embodiment, where the method includes:
the sampling unit is used for periodically sampling the secondary voltage output by the voltage transformer so as to obtain sampling data;
the average value calculating unit is used for calculating the average value of the voltage of the A phase, the B phase and the C phase according to the sampling data;
the voltage difference value calculating unit is used for calculating the voltage difference value between each two phases according to the average voltage values of the A phase, the B phase and the C phase;
the voltage deviation calculation unit is used for calculating the voltage deviation between each two phases according to the average voltage values of the A phase, the B phase and the C phase and the voltage difference value between each two phases; and
and the fault judging unit is used for judging whether the voltage transformer has faults or not according to the comparison result of the voltage deviation between each two phases and a preset deviation threshold value and preset judging logic.
Preferably, the system further comprises:
and the alarm unit is used for outputting alarm information corresponding to the fault type and storing the alarm information if the fault judgment unit judges the fault of the voltage transformer according to the comparison result of the voltage deviation between each two phases and a preset deviation threshold value and a preset judgment logic.
The above embodiment scheme has the following beneficial effects:
the secondary voltage output by the voltage transformer is periodically sampled to obtain sampling data, wherein the sampling data can be daily sampling data, weekly sampling data or monthly sampling data, voltage deviation between every two phases is calculated according to the sampling data, and whether the voltage transformer fails or not is finally judged according to a comparison result of the voltage deviation between every two phases and a preset deviation threshold value and preset judgment logic. The sampling of the secondary voltage output by the voltage transformer can be carried out under the condition of no power failure, the sampling is realized, the running state diagnosis of the voltage transformer is carried out according to the sampling data, the electric performance of the voltage transformer is normal when the power failure inspection occurs in the actual running process, the fault condition is generated in the running process, and the influence on the safe and stable running of power equipment and the safety of electric workers is avoided.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
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 description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the 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 diagram of a capacitor voltage transformer according to an embodiment of the present invention.
Fig. 3 is a block diagram of an operational status diagnostic system for a voltage transformer according to an embodiment of the present invention.
Detailed Description
Various exemplary embodiments, features and aspects of the present invention will be described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers can indicate functionally identical or similar elements. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.
In addition, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present invention. It will be understood by those skilled in the art that the present invention may be practiced without some of these specific details. In some instances, well known means have not been described in detail so as not to obscure 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, calculating the average voltage values of the A phase, the B phase and the C phase according to the sampling data;
step S3, calculating the voltage difference value between each two phases according to the average voltage value of the A phase, the B phase and the C phase;
step S4, calculating voltage deviation between each two phases according to the average voltage values of the A phase, the B phase and the C phase and the voltage difference value between each two phases;
and step S5, judging whether the voltage transformer has faults or not according to the comparison result of the voltage deviation between each two phases and a preset deviation threshold value and preset judgment logic.
Specifically, a Capacitor Voltage Transformer (CVT) is a voltage transformer that is divided by a series capacitor, and then stepped down and isolated by an electromagnetic transformer, and is used as a meter, a relay protection, and the like. Compared with an electromagnetic voltage transformer, the capacitor voltage transformer can prevent ferromagnetic resonance caused by saturation of an iron core of the voltage transformer, and has the advantages of high impact insulation strength, simplicity in manufacture, light weight, small size, low cost, reliability in operation, convenience in maintenance, capability of being used as a coupling capacitor for high-frequency carrier communication and the like. The main disadvantages are that the error characteristics are worse than that of the electromagnetic voltage transformer, and the output capacity is smaller, and the factors influencing the error (such as temperature, frequency and the like) are more. The accuracy of the TYD capacitive voltage transformer manufactured in China at present is improved to 0.5 level, and the TYD capacitive voltage transformer is widely applied to a direct neutral grounding system of 110kV or more.
The capacitor voltage transformer mainly comprises a capacitive voltage divider and an intermediate transformer. The capacitive voltage divider consists of a porcelain bushing and a plurality of series capacitors arranged in the porcelain bushing, and the porcelain bushing is filled with insulating oil. The medium voltage transformer consists of transformer, compensating reactor, lightning arrester and damper inside sealed oil tank. The capacitor type voltage transformer is essentially a capacitive voltage divider, and for convenience of analysis, the capacitor string is divided into two parts (also called as an upper capacitor C1 and a lower capacitor C2) of a main capacitor C1 and a voltage dividing capacitor C2, and each part is composed of a plurality of capacitors connected in series, as shown in fig. 2. T is an intermediate transformer, L is a compensation reactor, and BL is a protective lightning arrester connected in parallel at two ends of the compensation reactor. The intermediate transformer T and the compensation reactor L are provided with taps respectively used for adjusting the amplitude error and the phase error of the capacitor voltage transformer. 1a and 1n are a first group of secondary windings and are mainly used for measurement; 2a and 2n are a second group of secondary windings and are mainly used for protection; da. And dn is a third group of secondary windings which are connected with the other two groups of secondary windings in series and used for measuring zero sequence voltage. A fast saturation damper Z consisting of a reactance and a resistance is also connected in parallel across the third winding, mainly because the nonlinear impedance and the inherent capacitance of the capacitor voltage transformer sometimes cause ferromagnetic resonance in the capacitor voltage transformer, thus damping the resonance with a damping device. Under normal conditions, the damping device has high impedance, when ferromagnetic resonance causes overvoltage, and before the intermediate transformer is influenced, the reactor is saturated and only the residual resistance load is carried, so that the oscillation energy is reduced quickly.
Assuming that the voltage at the upper end of the capacitor 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 partial pressure ratio, and different partial pressure ratios can be obtained by changing the ratio of C1 to C2. When the part C1 is broken, C1 will become large and the intermediate transformer primary voltage will rise; when the section C2 breaks down, C2 will become larger and the intermediate transformer primary voltage will decrease. The corresponding secondary side voltage will also follow the change and the magnitude of the change is closely related to C1, C2.
Through the principle analysis of the capacitor voltage transformer, the output secondary voltage of the capacitor voltage transformer can be influenced when breakdown faults, intermediate transformer faults and secondary circuit faults occur to the upper and lower capacitors of the capacitor voltage transformer. The function of the voltage transformer is to convert the primary voltage into a qualified secondary voltage. Therefore, the operation state of the voltage transformer is judged by monitoring the secondary side voltage, and whether the voltage transformer has a fault or not is judged.
Wherein 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 along with the primary system voltage, and the primary system voltage changes at certain randomness. Therefore, the reference standard selected for monitoring the secondary side voltage cannot be the rated voltage of the voltage transformer. Meanwhile, the primary system load fluctuates with time, and thus the historical value cannot be simply selected as the reference standard. Because the power system operates three phases simultaneously, and the three-phase voltage transformers are basically put into operation at the same time by the same manufacturer. Therefore, the normal attenuation periods of the three-phase voltage transformer are consistent. The primary system load, although fluctuating all the time, is approximately balanced for a longer period of time. Therefore, the method selects the calendar history curve, the week history curve, the month history curve or the year history curve of the three-phase voltage transformer with the same bus or at intervals to judge the operating state of the voltage transformer.
In step S1, a sampling period is set, for example, a secondary voltage value is collected every 5 minutes, and the three-phase voltages are respectively UA1、UB1、UC1The three-phase voltage is U in the next sampling periodA2、UB2、UC2And in the same way, all sampling values are sent to a memory for storage. The secondary voltage value of every day three-phase voltage is the average value of all voltages on the day, namely:
in the formula of UAt、UBt、UCtThe average value of the three-phase voltage every equivalent day represents the voltage value of the day. The average value is used for replacing the instantaneous sampling value to reduce sampling error, voltage fluctuation of the power system and other factors to secondaryThe voltage influence. U shapeAi、UBi、UCiAnd the instantaneous sampling value represents the instantaneous sampling value of each sampling time point of the three-phase voltage at the current day, namely the instantaneous value of the three-phase voltage at a certain moment. n is the total number of voltage samples on the day, and this value can be calculated by a preset sampling period, for example, if the sampling period is 1 hour, then n is 24.
Wherein, the step S2 specifically includes:
calculating daily voltage average values of the A phase, the B phase and the C phase according to daily sampling data;
or, calculating the cycle voltage average value of the A phase, the B phase and the C phase according to the cycle sampling data;
alternatively, the average value of the monthly voltages of the A-phase, the B-phase and the C-phase is calculated from the monthly sampling data.
Specifically, the daily three-phase voltage values are calculated according to the above steps, then the daily voltage values are used to calculate the weekly voltage values, and the weekly voltage value calculation method and the daily voltage values are the same as the daily voltage values, namely, the average values of the phase voltages in the current week are respectively calculated, namely:
in the formula of UAz、UBz、UCzThe average value of the three-phase voltage per equivalent cycle respectively represents the current cycle voltage value. The average value is used for replacing the instantaneous sampling value, so that the influence of sampling errors, power system voltage fluctuation and other factors on the secondary voltage can be reduced. U shapeAti、UBti、UCtiRepresenting the daily voltage average value of the three-phase voltage. n is the total number of voltage sampling points in the current cycle, and the value n is 7.
According to the steps and by analogy, the voltage values of the three-phase voltage in each month and each year can be obtained.
Wherein, the step S3 specifically includes:
and calculating the voltage difference value between each two phases according to the daily voltage average value, the weekly voltage average value or the monthly voltage average value of the phase A, the phase B and the phase C.
Specifically, the daily voltage value, the weekly voltage value, the monthly voltage value and the annual voltage value of the three-phase voltages are obtained through the sampling and calculating method, and then the voltage values need to be further calculated to calculate the voltage difference value between the phase voltages. Namely:
ΔUAB＝UA-UB
ΔUBC＝UB-UC
ΔUCA＝UC-UA
when different voltages are used, different voltage difference values can be calculated, for example, when a daily voltage value is used, a daily voltage difference value can be calculated, and when a weekly voltage value is used, a weekly voltage difference value can be calculated.
Wherein, the step S4 specifically includes:
wherein, UAIs the average voltage value of phase A, UBIs the average voltage value of phase B, UCIs the average value of the voltage of the C phase,ΔUABis the voltage difference between the A, B phases,ΔUBCis the voltage difference between the B, C phases,ΔUCAis the voltage difference between the C, A phases,
In an embodiment, the step S5 specifically includes:
if only haveA, B two phases are abnormal, and phase C is normal;
if only haveB, C two phases are abnormal, phase A is normal;
if only haveA, C two phases are abnormal and B phase is normal;
if it is not
if it is notAnd is
if it is notAnd isThen phase C is abnormal, and phase A, B is normal;
if it is not
Specifically, the calculated deviation of each phase voltage is compared with a given voltage deviation standard, and when the calculated voltage deviation is larger than the given voltage deviation standard, the secondary voltage of the voltage transformer is judged to be abnormal, namely the secondary voltage of the voltage transformer is judged to be abnormalOr
It can be understood that, when only one of the three voltage deviations is greater than the voltage deviation standard, it is determined that the two-phase voltage transformer related to the voltage deviation is abnormal, that is, when only one of the three voltage deviations is greater than the voltage deviation standardThe two-phase voltage transformer is judged to be abnormal A, B. When two of the three voltage deviations are larger than the standard voltage deviation, the two voltage deviations are determinedThe voltage transformer of the phase concerned by the voltage deviation is abnormal, i.e. when only
In another embodiment, the step S5 specifically includes:
if a plurality of cycles are continued, only
if a plurality of cycles are continued, onlyB, C two phases are abnormal, phase A is normal;
if a plurality of cycles are continued, onlyA, C two phases are abnormal and B phase is normal;
if there are a plurality of cycles in succession,
if there are a plurality of cycles in succession,and isThen phase B is abnormal, and phase A, C is normal;
if there are a plurality of cycles in succession,and isThen phase C is abnormal, and phase A, B is normal;
if there are a plurality of cycles in succession,
Specifically, in the present embodiment, in order to eliminate the accidental interference and cause the occurrence of the erroneous determination, the voltage deviation comparison of a plurality of consecutive cycles may be used to determine that the voltage deviation exceeds the voltage deviation standard for a certain week of consecutive 3 weeks, and the voltage deviation exceeds the voltage deviation standard for a certain month of consecutive 2 months, so as to determine the fault.
In a specific embodiment, the method further comprises:
and if the voltage transformer fault is judged according to the comparison result of the voltage deviation between each two phases and a preset deviation threshold value and a preset judgment logic, outputting alarm information corresponding to the fault type, and storing the alarm information.
It can be understood that, in the above embodiments, due to the limitation of the current detection means and detection period of the voltage transformer, the voltage transformer cannot be found in time when abnormal or even fault exists, and the voltage transformer is used as a very important electrical device in the power system, and the healthy, safe and stable operation of the voltage transformer is related to whether the power system and the electrical device can normally operate, and the voltage difference and the voltage deviation in different periods can be found in time by monitoring the secondary output voltage of the voltage transformer in real time, so that the voltage transformer can be reminded of timely handling by electrical operation and maintenance personnel, and a large power accident can be avoided.
As can be seen from the above description of the embodiments, the present invention has the following advantages:
(1) the method can judge the running state of the voltage transformer according to the secondary output voltage of the voltage transformer, can monitor in real time, and finds and alarms at the first time after the voltage transformer is abnormal.
(2) The method can be widely applied to various conditions with three-phase voltage transformers.
(3) The method solves the problems that the upper voltage transformer is abnormal, and the fault finding is not calculated, does not need power failure of substation equipment, greatly reduces the rectification difficulty, and also reduces the rectification cost.
As shown in fig. 3, an embodiment of the present invention provides a voltage transformer operating state diagnostic system, which is configured to implement the method in the foregoing embodiment, and includes:
the sampling unit 1 is used for periodically sampling secondary voltage output by the voltage transformer to obtain sampling data;
an average value calculating unit 2, configured to calculate voltage average values of the a phase, the B phase, and the C phase according to the sampling data;
the voltage difference value calculating unit 3 is used for calculating the voltage difference value between each two phases according to the average voltage values of the A phase, the B phase and the C phase;
a voltage deviation calculation unit 4, configured to calculate a voltage deviation between each two phases according to the average voltage values of the a, B, and C phases and the voltage difference between each two phases; and
and the fault determination unit 5 is used for determining whether the voltage transformer has a fault according to a comparison result of the voltage deviation between each two phases and a preset deviation threshold value and preset determination logic.
In a specific embodiment, the system further comprises:
and the alarm unit 6 is configured to, if the fault determination unit 5 determines that the voltage transformer has a fault according to the comparison result between the voltage deviation between each two phases and the preset deviation threshold and the preset determination logic, output alarm information corresponding to the fault type by the alarm unit 6, and store the alarm information.
The above-described system embodiments are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.
It should be noted that the system described in the foregoing embodiment corresponds to the method described in the foregoing embodiment, and therefore, portions of the system described in the foregoing embodiment that are not described in detail can be obtained by referring to the content of the method described in the foregoing embodiment, and details are not described here.
Moreover, the lane identification system according to the above-mentioned embodiment may be stored in a computer-readable storage medium if it is implemented in the form of a software functional unit and sold or used as an independent product.
Specifically, the computer-readable storage medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, etc.
Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many 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 is chosen in order to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
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