CN114264890A - Non-contact type electrical parameter measurement and verification device and method for operating power equipment - Google Patents

Non-contact type electrical parameter measurement and verification device and method for operating power equipment Download PDF

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CN114264890A
CN114264890A CN202111580463.6A CN202111580463A CN114264890A CN 114264890 A CN114264890 A CN 114264890A CN 202111580463 A CN202111580463 A CN 202111580463A CN 114264890 A CN114264890 A CN 114264890A
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张建
尹娟
张方荣
高兴琼
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Gauss Electronics Technology Co ltd
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Abstract

The invention discloses a non-contact electrical parameter measurement and verification device and a non-contact electrical parameter measurement and verification method for operating power equipment, wherein the device comprises a voltage acquisition module, a current acquisition module, an AD conversion module and a signal processing module; the voltage acquisition module includes multichannel voltage acquisition unit, current acquisition module includes the current sensor coil, current sensor coil and each way voltage acquisition unit are used for gathering by survey electrical equipment to transmit the information of gathering respectively for AD conversion module and convert the back, give signal processing module with the signal transmission who obtains, signal processing module is used for carrying out abnormal analysis to equipment under test according to the information of AD conversion module output. The invention can realize measurement and verification of the electric parameters of the electrified electric equipment based on the non-contact acquisition of current and voltage under the condition that the measuring device is not in direct contact with the electric equipment.

Description

Non-contact type electrical parameter measurement and verification device and method for operating power equipment
Technical Field
The present invention relates to power equipment measurement, and more particularly to a non-contact electrical parameter measurement and verification device and method for operating power equipment.
Background
When measuring high-voltage electricity, the probe of the frequent testing device is in contact measurement with the tested equipment and then the voltage is measured through internal voltage reduction, and the voltage division ratio is improved in some occasions by adopting a mode of voltage division through capacitive coupling or capacitive coupling, but one end of a voltage division capacitor is strictly grounded in the mode, so that the frequent testing device is inconvenient in many occasions, especially applied to the environment of continuous monitoring, and the mode of voltage division and electricity measurement does not have installation conditions and also does not accord with safety specifications.
In some application occasions, it is required to evaluate whether a line is electrified, but no current (such as an idle line) exists in the line when a human body does not adopt an electrified detection device to contact the line, and once the monitoring device is connected, the current generation affects the voltage value and may cause a safety hazard. Therefore, in order to evaluate safety, the voltage signal can only be detected under the condition that the loop has no current, so that a current path cannot be formed by a voltage division and earthing mode, otherwise the numerical value of the measured voltage is influenced, and even the measured voltage cannot be captured.
In addition, measuring current can be accomplished by calipers or feedthrough current transformers, but current transformers do not have a voltage measurement function. If the voltage needs to be measured, a voltage measuring device needs to be matched, so that if the same test point needs two live-line work of current measurement and voltage measurement, a plurality of problems are caused when the test point is separated, and the phases of the voltage and the current cannot be accurately obtained.
If a plurality of devices need to be tested at the site with working voltage, the devices need to be tested independently (each point needs to be respectively tested with voltage or current), and a plurality of potential safety hazards exist in the middle section.
In most cases, it is also necessary to identify faults in the high-voltage line, which are insufficient depending on the voltage or current alone. It is necessary to monitor both voltage and current and calculate the power factor angle to achieve fault detection and fault location of the line.
In the aspect of discharge testing of equipment, partial discharge or temperature measurement is adopted for high-level voltage equipment at present, but the method is low in sensitivity or needs to contact with grounding current, so that personal hidden dangers exist, and therefore a solution is necessary to solve the problems in the aspects of measurement, monitoring and fault diagnosis of the current high-voltage equipment.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a non-contact type electrical parameter measurement and verification device and a non-contact type electrical parameter measurement and verification method for operating electrical equipment, which can realize measurement and verification of electrical parameters of electrified electrical equipment based on current and voltage non-contact acquisition under the condition that a measuring device is not in direct contact with the electrical equipment.
The purpose of the invention is realized by the following technical scheme: a non-contact electrical parameter measurement and verification device for operating power equipment comprises a voltage acquisition module, a current acquisition module, an AD conversion module and a signal processing module;
the voltage acquisition module includes multichannel voltage acquisition unit, current acquisition module includes the current sensor coil, current sensor coil and each way voltage acquisition unit are used for gathering by survey electrical equipment to transmit the information of gathering respectively for AD conversion module and convert the back, give signal processing module with the signal transmission who obtains, signal processing module is used for carrying out abnormal analysis to equipment under test according to the information of AD conversion module output.
Preferably, the AD conversion module includes a plurality of AD conversion channels, and the number of the AD conversion channels is greater than or equal to the total number of the voltage acquisition units and the current sensor coils.
Preferably, the multi-path voltage acquisition unit consists of a reference electrode and a plurality of measuring electrodes; each measuring electrode and the reference electrode form an equivalent capacitor, and each equivalent capacitor is used as a path of voltage acquisition unit;
in each voltage acquisition unit, the voltage between the measurement electrode and the reference electrode is taken as the output of the voltage acquisition unit.
A non-contact electrical parameter measurement and verification method for operating electrical equipment comprises the following steps:
s1, measuring the to-be-measured electric equipment to obtain working voltage amplitude and phase angle;
s2, calculating a power factor angle and active power, checking according to the power factor angle and the active power, and judging whether the equipment is abnormal or not;
s3, calculating the average electric field intensity, checking according to the average electric field intensity, and judging whether the detected electric equipment has the conditions of overproof radiant quantity, abnormal voltage, electric leakage and discharge;
and S4, calculating the average electric charge amount, checking according to the average electric charge amount, and judging whether the tested electric equipment has a bad condition.
Preferably, the step S1 includes:
s101, enabling each measuring electrode to face a tested electric device, and setting equivalent capacitance formed between each measuring electrode and a reference electrode as C1 and C2 … Ck; each equivalent capacitor outputs a voltage measurement signal;
s102, performing AD conversion on voltage signals output by equivalent capacitors C1 and C2 … Ck, and performing Fourier transform to obtain voltage sequences V1 and V2 … Vk; the phase angles of the voltage sequences corresponding to the equivalent capacitors C1 and C2 … Ck are respectively
Figure BDA0003427008540000023
Figure BDA0003427008540000024
The phase angle sequence is a power frequency phase obtained by respectively carrying out Fourier transform or wavelet transform on each voltage sequence V1 and V2 … Vk, wherein the power frequency refers to the working power frequency of the tested equipment;
s103, calculating voltage amplitude according to C1, C2 … Ck and corresponding voltage sequences V1, V2 … Vk:
the calculation method includes any one of the following calculation methods, wherein the capacitance C1 and the capacitance C2 … Ck are used as an X axis, X > is 0, the voltage V1 and the voltage V2 … Vk are used as a Y axis, and Y > is 0:
a1, designing a straight line y with the gradient k less than 0 as kx + k0 according to C1 and C2 … Ck and corresponding V1 and V2 … Vk, and calculating corresponding k0 as a voltage amplitude; when the capacitors C1, C2 and Ck and k are greater than 2, generating a plurality of straight lines, obtaining a plurality of k0 values, taking the average value of the plurality of k0 values as a k0 value, or randomly taking two capacitors and corresponding voltages to determine a straight line for calculation;
a2, substituting C1, C2 … Ck and corresponding V1, V2 … Vk into an exponential function y ═ a × e-kxCalculating corresponding k and A, wherein the value A is the voltage amplitude;
s104. according to C1, C2 … Ck and corresponding voltage sequence phase angles
Figure BDA0003427008540000021
Calculating a voltage phase angle:
the capacitance C1, C2 … Ck is taken as X axis, X>0, by phase angle
Figure BDA0003427008540000022
For the Y-axis, the calculation method includes any one of the following:
b1, according to C1, C2 … Ck and corresponding phase angles
Figure BDA0003427008540000035
Designing a straight line y with the slope k smaller than 0 as kx + k0, and calculating corresponding k0 as a voltage phase angle;
similarly, when the capacitances C1, C2, Ck and k are greater than 2, a plurality of straight lines are generated, a plurality of k0 values are obtained, the average value of the k0 values is used as a k0 value, or two capacitances and corresponding phases are arbitrarily taken to determine a straight line for calculation;
b2, C1, C2 … Ck and corresponding phase angles
Figure BDA0003427008540000036
Carry-in exponential function y ═ a × e-kxAnd calculating corresponding k and A, wherein the value of A is the voltage phase angle.
Preferably, the step S2 includes:
the amplitude and phase of the current output by the current sensor coil are respectively set as I,
Figure BDA0003427008540000031
the voltage amplitude and the voltage phase angle calculated in step S1 are respectively V,
Figure BDA0003427008540000032
then calculate:
apparent power S ═ V × I;
the power factor angle is:
Figure BDA0003427008540000033
active power:
Figure BDA0003427008540000034
in the verification process, when the apparent power or the active power exceeds a set threshold value, the tested device is considered to be abnormal.
Preferably, the step S3 includes:
s301, setting the distances between the measuring electrodes corresponding to the equivalent capacitors C1 and C2 … Ck and the reference electrode as d1 and d2 … dk;
s302, calculating the electric field intensity Ei corresponding to the equivalent capacitance Ci as follows:
Ei=Vi/di-E0
where E0 is the stray environment electric field strength, i is 1,2, …, k;
s303, when i is 1,2, …, k, repeatedly executing step S302 to obtain an electric field strength sequence E1, E2, …, Ek;
s304, calculating the average electric field intensity E:
E=(E1+E2+…+Ek)/k。
in the verification process, when the average field intensity is higher than the threshold, the radiation quantity of the tested electric equipment exceeds the standard, the voltage is abnormal or the phenomena of electric leakage and electric discharge occur.
Preferably, the step S4 includes:
calculating an average charge amount Q ═ E × r ═ β -Q0, β is a constant, β ═ 9.0 × 109Q0 is the stray environment charge, E is the average electric field strength; r is the space linear distance between the measuring and verifying device and the tested charged equipment;
in the verification process, when the average historical charge quantity is exceeded or the threshold value such as a design value is exceeded, the electric device to be tested is considered to be discharged, or the electric device to be tested is considered to be inclined and the electric field is not uniform.
Preferably, the method further comprises a measurement optimization step:
after each measuring electrode is over against the tested electrical equipment, the electrode angle at the moment is taken as a standard angle, the angle of the measuring electrode is adjusted for multiple times on the premise that the difference between the electrode angle and the standard angle is not more than plus or minus 15 degrees, the measurement is respectively carried out according to the steps S1-S4 after the standard angle and each adjustment, multiple groups of measurement data are obtained, the magnitude of the voltage amplitude in each group of measurement data is compared, and one group of data with the maximum voltage amplitude is taken as a final measurement result.
The invention has the beneficial effects that:
(1) simultaneously measuring the voltage and the current; voltage and current can also be measured separately asynchronously or separately;
(2) the voltage measurement can be performed without grounding, and the influence on the load capacity of the tested equipment is small; induced voltages can also be measured;
(3) by utilizing the voltage coupling of multiple electrodes, whether the voltage field of the tested high-voltage equipment has instability, namely partial discharge or harmonic wave can be diagnosed, so that the hidden danger of the tested equipment can be remotely diagnosed in a non-contact manner;
(4) the device can be used for field short-time live measurement (without grounding, such as being matched on an insulating rod) and continuous monitoring (the testing device does not need grounding).
(5) The condition for measuring the power factor is provided, and the line fault can be diagnosed through the power factor without a grounding terminal. Faults such as the power factor at the load end being less than 0.5 or the power factor of the load suddenly changing from capacitive to inductive are quickly identified.
(6) Under the condition of meeting the communication networking conditions, the device for measuring a plurality of different positions can complete the tests of voltage difference, current ratio, voltage ratio, fault positioning and the like of different equipment or different positions of the equipment in a plurality of areas. The transformer is particularly suitable for verifying the transformer transformation ratio and the sensor voltage division ratio in an electrified operation environment without contacting a high-voltage end.
(7) When a plurality of power equipment with different voltage grades and current densities exist on the site, the regional voltage grade or current density imaging or discharging regional imaging can be realized by combining a plurality of voltage acquisition units and current acquisition units into an array, and the voltage grade and the current density can be quickly distinguished or electrified and power-off equipment and the like can be quickly distinguished.
(8) When it is unclear how much the operating voltage of the charged equipment is, the operating voltage is checked to prepare for safety measures.
(9) When the load of the charged equipment is not clear, the equipment cannot be randomly approached to the measuring condition, and whether overload operation or short-circuit fault occurs is diagnosed by telemetering the load current.
Drawings
FIG. 1 is a schematic block diagram of the apparatus of the present invention;
FIG. 2 is a schematic view of embodiment 1;
FIG. 3 is a schematic view of embodiment 2;
FIG. 4 is a schematic view of embodiment 3;
fig. 5 is a schematic diagram illustrating a relationship between a capacitor and a terminal voltage in embodiment 3.
Detailed Description
The technical solutions of the present invention are further described in detail below with reference to the accompanying drawings, but the scope of the present invention is not limited to the following.
As shown in fig. 1, a non-contact electrical parameter measurement and verification device for operating power equipment includes a voltage acquisition module, a current acquisition module, an AD conversion module, and a signal processing module;
the voltage acquisition module includes multichannel voltage acquisition unit, current acquisition module includes the current sensor coil, current sensor coil and each way voltage acquisition unit are used for gathering by survey electrical equipment to transmit the information of gathering respectively for AD conversion module and convert the back, give signal processing module with the signal transmission who obtains, signal processing module is used for carrying out abnormal analysis to equipment under test according to the information of AD conversion module output.
In an embodiment of the present application, the AD conversion module includes a plurality of AD conversion channels, and the number of the AD conversion channels is greater than or equal to the total number of the voltage acquisition units and the current sensor coils.
In the embodiment of the application, the multi-path voltage acquisition unit is composed of a reference electrode and a plurality of measuring electrodes; each measuring electrode and the reference electrode form an equivalent capacitor, and each equivalent capacitor is used as a path of voltage acquisition unit;
in each voltage acquisition unit, the voltage between the measurement electrode and the reference electrode is taken as the output of the voltage acquisition unit.
In the embodiment of the application, the measuring device further comprises a communication module connected with the signal processing module, and the communication module is used for transmitting the measuring result to the monitoring background, so that the monitoring background can monitor or store the measuring result conveniently.
S1, measuring the to-be-measured electric equipment to obtain working voltage amplitude and phase angle;
s2, calculating a power factor angle and active power, checking according to the power factor angle and the active power, and judging whether the equipment is abnormal or not;
s3, calculating the average electric field intensity, checking according to the average electric field intensity, and judging whether the detected electric equipment has the conditions of overproof radiant quantity, abnormal voltage, electric leakage and discharge;
and S4, calculating the average electric charge amount, checking according to the average electric charge amount, and judging whether the tested electric equipment has a bad condition.
In an embodiment of the present application, the step S1 includes:
s101, enabling each measuring electrode to face a tested electric device, and setting equivalent capacitance formed between each measuring electrode and a reference electrode as C1 and C2 … Ck; each equivalent capacitor outputs a voltage measurement signal;
s102, performing AD conversion on voltage signals output by equivalent capacitors C1 and C2 … Ck, and performing Fourier transform to obtain voltage sequences V1 and V2 … Vk; the phase angles of the voltage sequences corresponding to the equivalent capacitors C1 and C2 … Ck are respectively
Figure BDA0003427008540000051
Figure BDA0003427008540000052
The phase angle sequence is a power frequency phase sequence obtained by respectively carrying out Fourier transform or wavelet transform on each voltage sequence V1 and V2 … Vk, wherein the power frequency refers to the working power frequency of the tested equipment;
s103, calculating voltage amplitude according to C1, C2 … Ck and corresponding voltage sequences V1, V2 … Vk:
the calculation method includes any one of the following calculation methods, wherein the capacitance C1 and the capacitance C2 … Ck are used as an X axis, X > is 0, the voltage V1 and the voltage V2 … Vk are used as a Y axis, and Y > is 0:
a1, designing a straight line y with the gradient k less than 0 as kx + k0 according to C1 and C2 … Ck and corresponding V1 and V2 … Vk, and calculating corresponding k0 as a voltage amplitude; when the capacitors C1, C2 and Ck and k are greater than 2, generating a plurality of straight lines, obtaining a plurality of k0 values, taking the average value of the plurality of k0 values as a k0 value, or randomly taking two capacitors and corresponding voltages to determine a straight line for calculation;
a2, substituting C1, C2 … Ck and corresponding V1, V2 … Vk into an exponential function y ═ a × e-kxCalculating corresponding k and A, wherein the value A is the voltage amplitude;
s104. according to C1, C2 … Ck and corresponding voltage sequence phase angles
Figure BDA0003427008540000065
Calculating a voltage phase angle:
the capacitance C1, C2 … Ck is taken as X axis, X>0, by phase angle
Figure BDA0003427008540000066
For the Y-axis, the calculation method includes any one of the following:
b1, according to C1, C2 … Ck and corresponding phase angles
Figure BDA0003427008540000067
Designing a straight line y with the slope k smaller than 0 as kx + k0, and calculating corresponding k0 as a voltage phase angle;
similarly, when the capacitances C1, C2, Ck and k are greater than 2, a plurality of straight lines are generated, a plurality of k0 values are obtained, the average value of the k0 values is used as a k0 value, or two capacitances and corresponding phases are arbitrarily taken to determine a straight line for calculation;
b2, C1, C2 … Ck and corresponding phase angles
Figure BDA0003427008540000068
Carry-in exponential function y ═ a × e-kxAnd calculating corresponding k and A, wherein the value of A is the voltage phase angle.
In an embodiment of the present application, the step S2 includes:
the amplitude and phase of the current output by the current sensor coil are respectively set as I,
Figure BDA0003427008540000061
the voltage amplitude and the voltage phase angle calculated in step S1 are respectively V,
Figure BDA0003427008540000062
then calculate:
apparent power S ═ V × I;
the power factor angle is:
Figure BDA0003427008540000063
active power:
Figure BDA0003427008540000064
in the verification process, when the apparent power or the active power exceeds a set threshold value, the tested device is considered to be abnormal.
Preferably, the step S3 includes:
s301, setting the distances between the measuring electrodes corresponding to the equivalent capacitors C1 and C2 … Ck and the reference electrode as d1 and d2 … dk;
s302, calculating the electric field intensity Ei corresponding to the equivalent capacitance Ci as follows:
Ei=Vi/di-E0
where E0 is the stray environment electric field strength, i is 1,2, …, k;
s303, when i is 1,2, …, k, repeatedly executing step S302 to obtain an electric field strength sequence E1, E2, …, Ek;
s304, calculating the average electric field intensity E:
E=(E1+E2+…+Ek)/k。
in the verification process, when the average field intensity is higher than the threshold, the radiation quantity of the tested electric equipment exceeds the standard, the voltage is abnormal or the phenomena of electric leakage and electric discharge occur.
In an embodiment of the present application, the step S4 includes:
calculating an average charge amount Q ═ E × r ═ β -Q0, β is a constant, β ═ 9.0 × 109Q0 is the stray environment charge, E is the average electric field strength; r is the space linear distance between the measuring and verifying device and the tested charged equipment;
in the verification process, when the average historical charge quantity is exceeded or the threshold value such as a design value is exceeded, the electric device to be tested is considered to be discharged, or the electric device to be tested is considered to be inclined and the electric field is not uniform.
Obviously, when the average electric field intensity E and the charge amount Q are considered to be known stable amounts, the effective distance r between the tester and the tested electric equipment can also be calculated according to the above relation equivalent transformation.
In an embodiment of the application, the method further comprises a measurement optimization step:
after each measuring electrode is over against the tested electrical equipment, the electrode angle at the moment is taken as a standard angle, the angle of the measuring electrode is adjusted for multiple times on the premise that the difference between the electrode angle and the standard angle is not more than plus or minus 15 degrees, the measurement is respectively carried out according to the steps S1-S4 after the standard angle and each adjustment, multiple groups of measurement data are obtained, the magnitude of the voltage amplitude in each group of measurement data is compared, and one group of data with the maximum voltage amplitude is taken as a final measurement result.
The present application is further illustrated by the following specific examples:
example 1, as shown in figure 2. The voltage electrode and the current coil respectively form a voltage sensing unit and a current sensing unit which are arranged in parallel, so that the voltage sensing unit and the current sensing unit are combined into an integrated device in an open shape, an open hook shape or a plane shape. The opening direction is aligned with the tested circuit or the tested device, or is aligned with or close to the tested device after being designed into a plane;
for convenience of explanation, the combination of the voltage sensing unit and the current sensing unit is referred to as a composite sensor.
If the voltage measurement is carried out on a 110kV power-off line, the power-off line has no voltage under the general condition. However, other nearby non-power-off lines can be coupled with high voltage to the power-off line during power outage, so that the power-off line can be electrified instantaneously, and a maintainer can get an electric shock if a detection tool is lacked. If direct through the instrument measurement, because the ground terminal ground connection of instrument can cause induced voltage to release fast, consequently the induced voltage of surveying can not be accurate in quantity in addition, still can not survey voltage, but when the instrument removed the power failure circuit after, the power failure circuit can resume the voltage that the coupling was come fast, leads to the human body to electrocute. Moreover, when the meter is used for measuring, people are nervous and can touch the line to get an electric shock carelessly. After adopting this device, utilize the insulator spindle to prop up the alignment with compound sensor and be surveyed the circuit, then gather or instruct at the insulator spindle top with the voltage current output of this patent device, after voltage sensing unit detects voltage, audible and visual alarm immediately reminds the staff that the circuit is electrified this moment.
Embodiment 2, as shown in fig. 3, the voltage and current sensing units are oppositely arranged to form a feed-through or open-close type composite sensor;
similar to embodiment 1, the composite sensor can be hung or sleeved on a line, and after the composite sensor is matched with a collection and communication device, the power factor, current, voltage and power of the line can be monitored in real time under the condition that the line is continuously electrified, so that the composite sensor is particularly suitable for monitoring the power factor abnormality, electricity stealing, short circuit, discharging and the like of a region of the line in real time by arranging a plurality of monitoring devices on the line, and can rapidly distinguish the position where a fault occurs.
When the circuit has a power failure, if coupling voltage crosstalk exists, the composite sensor is matched with the voltage indication early warning device, whether the circuit is electrified or not can be indicated through sound and light in real time, and a maintainer is reminded of keeping away.
Because no equipment contacts the ground end in the processes of electrification and power failure, the load of a line cannot be influenced, and safety accidents such as ground short circuit and discharge cannot be caused.
Example 3, as shown in fig. 4, voltage measurement of the line was achieved by the sensor of this patent. The voltage sensor is composed of a plurality of parallel rectangular coupling electrodes as shown in the following figure; for example, the analog-digital converter of the figure collects voltage values output by a plurality of capacitors, for example, the figure C1 corresponds to the voltage V1, the figure C2 corresponds to the voltage V2, the figure C3 corresponds to the voltage V3, and the like when more electrodes exist. Obviously, the C1 capacitance is the smallest, corresponding to V1 being the highest, V2 being the second, V3 being the second.
By said exponential function y ═ A × e-kxAnd calculating the voltage of the measured line, wherein x is a capacitance value and y is a voltage value of the capacitance in the equation, and solving the equation to obtain the values of A and k. The A value is the voltage value of the tested circuit.
If the calculation equation used is a straight line, which is consistent with the exponential curve and belongs to the attenuation characteristic with increasing capacitance, then the equation is y-kx + K0 and the value of K0 needs to be calculated.
As shown in fig. 5, regardless of which equation is adopted, the final calculation is the value of y at x-0 on the curve described by the corresponding equation, that is: the y-axis tangent value.
This embodiment can be accomplished high voltage line by the staff who stands on ground, the operating voltage of high-voltage equipment measures to through the quantity that increases electric capacity C, can accomplish very accurate measurement.
Example 4: the data from example 3 were further modified.
The composite sensor is also provided with a gradient or inclination angle measuring unit. When the composite sensor is not strictly parallel to the measured line, the angle between the two is adjusted
Figure BDA0003427008540000081
Make a correction, i.e.
Figure BDA0003427008540000082
Is realized in the following manner.
If further accuracy improvement is required, a plurality of composite sensors can be arranged, each composite sensor has a different angle, and then the respective calculated voltage values are compared to obtain an optimal value.
Or under the cooperative work of the analog-to-digital converter and the microprocessor, outputting and displaying the calculated voltage value in real time. Then, by slightly adjusting the relative position of the composite sensor and the measured circuit and then observing the displayed voltage value, the maximum value is taken as the actual working voltage value of the measured device in principle.
Example 5: the device to be tested is aligned to carry out discharge test by manual work, and whether the device to be tested discharges or not is observed through voltage waveform jitter between different capacitances (capacitances between a measuring electrode and a reference electrode) in the voltage sensor. Or the multi-path voltage acquisition unit is designed into a feed-through structure and is directly clamped or sleeved on the tested equipment, typically equipment parts such as transformer bushings, cables, lines, insulators and the like which are convenient to clamp, an internal digital processing module is used for measuring, signals are transmitted out through a communication module, and the signals are observed or further calculated and diagnosed by receiving equipment.
Example 6: and (5) operating transformer transformation ratio and error measurement.
Two sets of non-contact electrical parameter measurement and verification devices for operating electrical equipment are adopted to synchronously measure the high-voltage side and the low-voltage side of the voltage transformer, the ratio of measured data is calculated to be used as a voltage ratio, and if the ratio is compared with a standard voltage transformation ratio, the error of the voltage ratio can also be calculated.
The voltage phase difference between the high-voltage side and the low-voltage side can be used for calculating the voltage angle difference of the voltage transformer.
In the same method, the two sets of devices synchronously measure the primary current and the secondary current of the current transformer, and the measured current ratio is used as a current ratio, and if the current ratio is compared with a standard current transformation ratio, the error of the current ratio can be calculated.
Wherein one timeThe magnitude of the current can be corrected by means of a voltage detection unit, i.e. by means of an exponential function y ═ a × e of the voltage measurement-kxOr a straight line function y is kx + k0, and the target current value y when x is zero is obtained as the current value of the current transformer to be measured. The specific model is completely referred to a curve calculated by parameters acquired by a voltage acquisition unit, only a measured current value is taken as a point on an exponential function or a linear function, and then a value at which x is 0 is found along the curve to be taken as a final current.
Also, the current phase difference of the high voltage side (primary side) and the low voltage side (secondary side) can be used to calculate the current angle difference of the current transformer.
Therefore, based on the scheme of the patent, the transformation ratio remote measurement can be realized, and whether the wiring error of the line causes the great transformation ratio deviation is checked based on the transformation ratio remote measurement value; and the metering error of the mutual inductor can be calculated, and whether serious ratio error or angular difference exists or not can be found.
Example 7: and (4) carrying out imaging measurement on the area voltage.
The imaging measurement units are arranged in an 8 x 8 array, that is, 64 composite sensors are adopted. Each composite sensor contains the multi-channel voltage sensor and the current sensor.
The whole electrode is designed by adopting a miniature printing film, and the current sensor is designed by adopting a PCB (printed Circuit Board) printing coil, so that the miniature sensor can be designed, and the volume of the whole array is reduced.
And the number of the multiple voltage sensors included in each array element is 3, and the number of the current sensors is 1, namely each array element has 4 signal outputs. The 8 × 8 array has 256 outputs, 64 × 4.
The analog quantity output of the array sensor is respectively connected to the ADC analog-to-digital converters of 256 channels, and synchronous 256-channel signal rapid acquisition is completed under the high-speed control of the FPGA programmable logic control device.
At the software end, one or more of the voltage value, the current value, the power factor and the voltage-current phase difference measured by each array element are automatically calculated, and then an area imaging algorithm is generated through a mathematical algorithm, or a calculated voltage imaging map is combined with a video by combining a graphic sensor (such as a camera) to form an image of the area voltage level.
Through this patent based on array element measuring formation of image atlas mode, can reach following effect at least:
(1) the voltage differences of the device groups are distinguished, for example, the highest voltage device is marked red and the lowest voltage is marked gray. The voltage difference in the equipment group can be observed clearly, for example, the voltage difference between the high-voltage side and the low-voltage side of the transformer, the voltage difference between the high-voltage line and the low-voltage line, the voltage difference between the reactive compensation equipment and the primary and secondary equipment of the transformer and the like can be observed clearly in a 500kV transformer substation.
(2) The equipment can be verified to be charged or power-off in a non-contact mode.
If the signal of the power transmission line is weak, the interference after power failure can be caused, or the fault short circuit can be caused, but the line is still electrified, so that the current sensing unit can observe that the current of the equipment to be tested is larger, and the equipment still belongs to electrified equipment and is not suitable for direct contact. (this effect is of course also applicable to a single measurement unit, i.e. a measurement module comprising one array element-multiple voltage and 1-current measurement units, but for an environment where multiple live devices are operating, imaging with array elements is more intuitive and it is easier to find short-circuit fault areas).
(3) Rapidly finding out the unbalance of three-phase voltage or three-phase current; or quickly find a phase fault of the three-phase line.
Obviously, this patent scheme has all played very practical, positive effect to promoting transformer substation, outdoor overhead line, the safety inspection and the troubleshooting of factory live equipment.
The scheme can be typically used for high-voltage lines, substations, railway systems, energy storage stations, power stations and the like, can quickly identify electrified and power-off equipment, and can quickly identify electrified equipment with different voltage grades.
For clarity of description, the above embodiments mainly refer to lines or cables, and actually, the device of the present invention may be used for various live equipment, especially for high voltage equipment, such as transformers, insulation sleeves, GIS combined electrical appliances, transformers, insulators, lightning arresters, capacitors, switch cabinets, site comprehensive observation of multiple high voltage equipment, etc., it is preferable that it has a CT-shaped design with a through or open-close structure in terms of accurately measuring voltage, and multiple voltage measuring electrodes and current measuring coils are embedded in a CT inner ring, so as to shield interference of other lines when measuring voltage and current. In other occasions, the invention can be used for measurement and monitoring, and can also be used for checking the electrification of equipment, especially for safety inspection, induced voltage early warning during maintenance and the like, and has good application value in the fields of safety monitoring of intelligent sensors, intelligent electrical parameter measuring chips, high-precision and high-integration combined transformers, lines or power equipment, intelligent power equipment matched with precision sensors, voltage grade imaging of substations or lines, current density imaging sensors or testing equipment.

Claims (9)

1. The utility model provides an operation power equipment non-contact electrical parameter measures and verifies device which characterized in that: the device comprises a voltage acquisition module, a current acquisition module, an AD conversion module and a signal processing module;
the voltage acquisition module includes multichannel voltage acquisition unit, current acquisition module includes the current sensor coil, current sensor coil and each way voltage acquisition unit are used for gathering by survey electrical equipment to transmit the information of gathering respectively for AD conversion module and convert the back, give signal processing module with the signal transmission who obtains, signal processing module is used for carrying out abnormal analysis to equipment under test according to the information of AD conversion module output.
2. The device of claim 1, wherein the device comprises: the AD conversion module comprises a plurality of AD conversion channels, and the number of the AD conversion channels is larger than or equal to the total number of the voltage acquisition units and the current sensor coils.
3. The device of claim 1, wherein the device comprises: the multi-path voltage acquisition unit consists of a reference electrode and a plurality of measuring electrodes; each measuring electrode and the reference electrode form an equivalent capacitor, and each equivalent capacitor is used as a path of voltage acquisition unit;
in each voltage acquisition unit, the voltage between the measurement electrode and the reference electrode is taken as the output of the voltage acquisition unit.
4. A non-contact electrical parameter measurement and verification method for operating electrical equipment, based on the measurement and verification device of any one of claims 1 to 3, characterized in that: the method comprises the following steps:
s1, measuring the to-be-measured electric equipment to obtain working voltage amplitude and phase angle;
s2, calculating a power factor angle and active power, checking according to the power factor angle and the active power, and judging whether the equipment is abnormal or not;
s3, calculating the average electric field intensity, checking according to the average electric field intensity, and judging whether the detected electric equipment has the conditions of overproof radiant quantity, abnormal voltage, electric leakage and discharge;
and S4, calculating the average electric charge amount, checking according to the average electric charge amount, and judging whether the tested electric equipment has a bad condition.
5. The method of claim 4, wherein the method comprises: the step S1 includes:
s101, enabling each measuring electrode to face a tested electric device, and setting equivalent capacitance formed between each measuring electrode and a reference electrode as C1 and C2 … Ck; each equivalent capacitor outputs a voltage measurement signal;
s102, performing AD conversion on voltage signals output by equivalent capacitors C1 and C2 … Ck, and performing Fourier transform to obtain voltage sequences V1 and V2 … Vk;
the phase angles of the voltage sequences corresponding to the equivalent capacitors C1 and C2 … Ck are respectively
Figure FDA0003427008530000011
In which the phase angle sequence is byRespectively carrying out Fourier or wavelet transformation on each voltage sequence V1 and V2 … Vk to obtain a power frequency phase, wherein the power frequency refers to the working power supply frequency of the tested equipment;
s103, calculating voltage amplitude according to C1, C2 … Ck and corresponding voltage sequences V1, V2 … Vk:
the calculation method includes any one of the following calculation methods, wherein the capacitance C1 and the capacitance C2 … Ck are used as an X axis, X > is 0, the voltage V1 and the voltage V2 … Vk are used as a Y axis, and Y > is 0:
a1, designing a straight line y with the gradient k less than 0 as kx + k0 according to C1 and C2 … Ck and corresponding V1 and V2 … Vk, and calculating corresponding k0 as a voltage amplitude;
when the capacitors C1, C2 and Ck and k are greater than 2, generating a plurality of straight lines, obtaining a plurality of k0 values, taking the average value of the plurality of k0 values as a k0 value, or randomly taking two capacitors and corresponding voltages to determine a straight line for calculation;
a2, substituting C1, C2 … Ck and corresponding V1, V2 … Vk into an exponential function y ═ a × e-kxCalculating corresponding k and A, wherein the value A is the voltage amplitude;
s104. according to C1, C2 … Ck and corresponding voltage sequence phase angles
Figure FDA0003427008530000021
Calculating a voltage phase angle:
the capacitance C1, C2 … Ck is taken as X axis, X>0, by phase angle
Figure FDA0003427008530000022
For the Y-axis, the calculation method includes any one of the following:
b1, according to C1, C2 … Ck and corresponding phase angles
Figure FDA0003427008530000023
Designing a straight line y with the slope k smaller than 0 as kx + k0, and calculating corresponding k0 as a voltage phase angle;
similarly, when the capacitances C1, C2, Ck and k are greater than 2, a plurality of straight lines are generated, a plurality of k0 values are obtained, the average value of the k0 values is used as a k0 value, or two capacitances and corresponding phases are arbitrarily taken to determine a straight line for calculation;
b2, C1, C2 … Ck and corresponding phase angles
Figure FDA0003427008530000024
Carry-in exponential function y ═ a × e-kxAnd calculating corresponding k and A, wherein the value of A is the voltage phase angle.
6. The method of claim 4, wherein the method comprises: the step S2 includes:
the amplitude and phase of the current output by the current sensor coil are respectively set as I,
Figure FDA0003427008530000025
the voltage amplitude and the voltage phase angle calculated in step S1 are respectively V,
Figure FDA0003427008530000026
then calculate:
apparent power S ═ V × I;
the power factor angle is:
Figure FDA0003427008530000027
active power:
Figure FDA0003427008530000028
in the verification process, when the apparent power or the active power exceeds a set threshold value, the tested device is considered to be abnormal.
7. The method of claim 4, wherein the method comprises: the step S3 includes:
s301, setting the distances between the measuring electrodes corresponding to the equivalent capacitors C1 and C2 … Ck and the reference electrode as d1 and d2 … dk;
s302, calculating the electric field intensity Ei corresponding to the equivalent capacitance Ci as follows:
Ei=Vi/di-E0
where E0 is the stray environment electric field strength, i is 1,2, …, k;
s303, when i is 1,2, …, k, repeatedly executing step S302 to obtain an electric field strength sequence E1, E2, …, Ek;
s304, calculating the average electric field intensity E:
E=(E1+E2+…+Ek)/k
in the verification process, when the average field intensity is higher than the threshold, the radiation quantity of the tested electric equipment exceeds the standard, the voltage is abnormal or the phenomena of electric leakage and electric discharge occur.
8. The method of claim 4, wherein the method comprises: the step S4 includes:
calculating an average charge amount Q ═ E × r ═ β -Q0, β is a constant, β ═ 9.0 × 109Q0 is the stray environment charge, E is the average electric field strength; r is the space linear distance between the measuring and verifying device and the tested charged equipment;
in the verification process, when the average historical charge quantity is exceeded or the threshold value such as a design value is exceeded, the electric device to be tested is considered to be discharged, or the electric device to be tested is considered to be inclined and the electric field is not uniform.
9. The method of claim 4, wherein the method comprises: the method further comprises a measurement optimization step:
after each measuring electrode is over against the tested electrical equipment, the electrode angle at the moment is taken as a standard angle, the angle of the measuring electrode is adjusted for multiple times on the premise that the difference between the electrode angle and the standard angle is not more than plus or minus 15 degrees, the measurement is respectively carried out according to the steps S1-S4 after the standard angle and each adjustment, multiple groups of measurement data are obtained, the magnitude of the voltage amplitude in each group of measurement data is compared, and one group of data with the maximum voltage amplitude is taken as a final measurement result.
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