CN114264890B - Non-contact type electric parameter measurement and verification device and method for operating power equipment - Google Patents
Non-contact type electric parameter measurement and verification device and method for operating power equipment Download PDFInfo
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Abstract
The invention discloses a non-contact type electric parameter measurement verification device and method for operating electric equipment, wherein the non-contact type electric parameter measurement verification device comprises a voltage acquisition module, a current acquisition module, an AD conversion module and a signal processing module; the voltage acquisition module comprises a plurality of paths of voltage acquisition units, the current acquisition module comprises a current sensor coil, the current sensor coil and each path of voltage acquisition unit are used for acquiring tested power equipment, acquired information is respectively transmitted to the AD conversion module for conversion, the acquired signals are transmitted to the signal processing module, and the signal processing module is used for carrying out anomaly analysis on the tested equipment according to the information output by the AD conversion module. According to the invention, under the condition that the measuring device is not in direct contact with the electric power equipment, measurement verification of the electric parameters of the electrified electric power equipment can be realized based on non-contact acquisition of current and voltage.
Description
Technical Field
The invention relates to power equipment measurement, in particular to a non-contact type electric parameter measurement verification device and method for operating power equipment.
Background
When measuring high-voltage electricity, the probe of the frequent testing device is used for measuring the voltage by contacting with the tested equipment and then reducing the voltage internally, and the voltage dividing ratio is improved in some occasions by adopting a capacitance or resistance-capacitance coupling voltage dividing mode, but one end of the voltage dividing capacitor is required to be strictly grounded in the mode, so that a plurality of fields are inconvenient to combine, and the voltage dividing and electricity measuring mode is not provided with mounting conditions and does not meet the safety specification especially when being applied to the environment of continuous monitoring.
Some applications require an assessment of whether the line is live, but when the live detection device is not in contact with the line, no current is present in the line (such as an empty line), and once the detection device is connected, the voltage value is affected and potential safety hazards may be caused. Therefore, in order to evaluate whether the circuit is safe or not, the voltage signal can only be detected under the condition that the circuit has no current, so that a current path cannot be formed through a voltage division and grounding mode, otherwise, the magnitude of the measured voltage is influenced, and even the measured voltage cannot be captured.
In addition, the measurement of the current can be accomplished by a caliper or a through current transformer, but the current transformer does not have a voltage measurement function. If voltage measurement is required, a voltage measurement device is also required to cooperate, so that if two live working operations of current measurement and voltage measurement are required for the same test point, a plurality of problems can be caused when the two live working operations are performed separately, such as that the phases of voltage and current cannot be accurately obtained.
If a plurality of devices need to be tested in a live mode to work voltage, the devices also need to be tested independently one by one (each point needs to be respectively tested by voltage or current), and a plurality of potential safety hazards exist in each middle ring.
In most cases, it is also necessary to identify faults in the high voltage line, which is insufficient by means of 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 localization of the line.
In the aspect of discharge test of equipment, the high-grade voltage equipment adopts a partial discharge or temperature measurement mode at present, but the mode is low in sensitivity or needs to be contacted with ground current, so that personal hidden danger exists, and a solution is required to be provided for the problems of measurement, monitoring and fault diagnosis of the high-grade voltage equipment at present.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, and provides a non-contact type electric parameter measurement verification device and method for operating electric equipment, which can realize measurement verification of the electric parameters of the electrified electric equipment based on non-contact acquisition of current and voltage under the condition that a measurement device is not in direct contact with the electric equipment.
The aim of the invention is realized by the following technical scheme: the non-contact type electric parameter measurement and verification device for the operation power equipment comprises a voltage acquisition module, a current acquisition module, an AD conversion module and a signal processing module;
the voltage acquisition module comprises a plurality of paths of voltage acquisition units, the current acquisition module comprises a current sensor coil, the current sensor coil and each path of voltage acquisition unit are used for acquiring tested power equipment, acquired information is respectively transmitted to the AD conversion module for conversion, the acquired signals are transmitted to the signal processing module, and the signal processing module is used for carrying out anomaly analysis on the tested equipment according to the information output by the AD conversion module.
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 unit and the current sensor coil.
Preferably, 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 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 verification method for operating an electrical device, comprising the steps of:
S1, measuring the power equipment to be measured to obtain working voltage amplitude and phase angle;
S2, calculating a power factor angle and active power, and 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, and performing verification according to the average electric field intensity, and judging whether the detected power equipment has the conditions of exceeding the standard of radiation quantity, abnormal voltage, electric leakage and discharge;
s4, calculating the average charge quantity, and accordingly checking to judge whether the tested power equipment has a fault or not.
Preferably, the step S1 includes:
s101, enabling each measuring electrode to face a tested power device, and setting equivalent capacitance formed between each measuring electrode and a reference electrode as C1, C2 … Ck; each equivalent capacitor outputs a voltage measurement signal;
s102, carrying out AD conversion on voltage signals output by equivalent capacitors C1 and C2 … Ck, and carrying out Fourier transformation to obtain a voltage sequence V1 and V2 … Vk; the phase angles of the voltage sequences corresponding to the equivalent capacitors C1, C2 … Ck are respectively The phase angle sequences are power frequency phases obtained by performing Fourier or wavelet transformation on each voltage sequence V1, V2 … Vk respectively, and 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:
with the capacitances C1, C2 … Ck as X-axis, X > =0, and the voltages V1, V2 … Vk as Y-axis, Y > =0, the calculation method includes any one of the following:
a1, according to C1, C2 … Ck and corresponding V1, V2 … Vk, designing a straight line y=kx+k0 with a slope k smaller than 0, and calculating corresponding k0 as a voltage amplitude; when the capacitance C1, C2, ck and k >2, generating a plurality of straight lines, obtaining a plurality of k0 values, taking the average value of the k0 values as the k0 value, or arbitrarily taking two capacitances 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. -kx, and calculating corresponding k, wherein the value A is the voltage amplitude;
s104, according to the phase angle of C1, C2 … Ck and the corresponding voltage sequence Calculating a voltage phase angle:
with the capacitor C1, C2 … Ck as X-axis, X > =0, with phase angle For the Y axis, the calculation mode comprises any one of the following:
b1, according to C1, C2 … Ck and corresponding phase angles Designing a straight line y=kx+k0 with a slope k smaller than 0, and calculating a corresponding k0 as a voltage phase angle;
Similarly, when the capacitances C1, C2, ck, k >2, a plurality of straight lines are generated, a plurality of k0 values are obtained, and an average value of the plurality of k0 values is taken as the 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 And carrying out an exponential function y=A.e -kx, and calculating corresponding k and A, wherein the A value is the voltage phase angle.
Preferably, the step S2 includes:
the current amplitude and the phase of the current output by the current sensor coil are respectively I, The voltage amplitude and the voltage phase angle calculated in the step S1 are V,/>, respectively
Then calculate:
Apparent power s=v×i;
The power factor angle is:
Active power:
During verification, the tested device is considered to be abnormal when the apparent power or the active power exceeds a set threshold value.
Preferably, the step S3 includes:
s301, setting the distances from a measuring electrode to a reference electrode, which correspond to equivalent capacitors C1 and C2 … Ck, as d1 and d2 … dk;
S302, calculating the electric field intensity Ei corresponding to the equivalent capacitance Ci as follows:
Ei＝Vi/di-E0
wherein E0 is the stray ambient electric field strength, i=1, 2, …, k;
S303, repeatedly executing the step S302 when i=1, 2, … and k to obtain electric field strength sequences E1, E2, … and Ek;
s304, calculating average electric field strength E:
E＝(E1+E2+…+Ek)/k。
in the verification process, when the average field intensity is higher than a threshold, the radiation quantity of the tested power equipment is considered to exceed the standard, the voltage is abnormal or the electric leakage and discharge phenomena occur.
Preferably, the step S4 includes:
calculating an average charge quantity Q=E×r/beta-Q0, wherein beta is a constant, beta=9.0× 9, Q0 is a stray environmental charge, and E is an average electric field intensity; 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 the design value is exceeded, the tested power equipment is considered to be discharged, or the tested power equipment is considered to be inclined and the electric field is not uniform.
Preferably, the method further comprises a measurement optimization step:
And after each measuring electrode is over against the measured power equipment, taking the electrode angle at the moment as a standard angle, adjusting the angle of the measuring electrode for a plurality of times on the premise that the difference between the angle and the standard angle is not more than plus or minus 15 degrees, measuring according to the steps S1-S4 after the standard angle and each adjustment respectively to obtain a plurality of groups of measuring data, and comparing the magnitude of the voltage amplitude in each group of measuring data, wherein one group of data with the largest voltage amplitude is taken as a final measuring result.
The beneficial effects of the invention are as follows:
(1) Simultaneously measuring voltage and current; the voltage and current can also be measured asynchronously alone or independently;
(2) The voltage measurement can be not grounded, and the influence on the load carrying capacity of the tested equipment is small; the induced voltage can also be measured;
(3) The voltage coupling of multiple electrodes is utilized to diagnose whether the instability exists in the voltage field of the tested high-voltage equipment, namely partial discharge or harmonic waves, so that the hidden danger of the tested equipment is remotely diagnosed in a non-contact mode;
(4) The device can be used for field short-time live measurement (without grounding, such as being matched with an insulating rod) and continuous monitoring (the testing device is not required to be grounded).
(5) With the condition of measuring the power factor, the line fault can be diagnosed by the power factor without a grounding terminal. If the power factor of the load end is smaller than 0.5, or the power factor of the load is rapidly identified by faults such as sudden change of capacity to sensitivity.
(6) The device for measuring the multiple different positions can finish the tests of voltage differences, current ratios, voltage ratios, fault positioning and the like of different equipment or different positions of the equipment in multiple areas under the condition of meeting the communication networking. The method is particularly suitable for verifying the transformer transformation ratio and the sensor voltage division ratio in the running electrified environment without contacting a high-voltage terminal.
(7) When a plurality of electric power equipment with different voltage classes and current densities are arranged on the site, the voltage class or the current density imaging or the discharging area imaging can be realized by combining a plurality of voltage acquisition units and current acquisition units into an array, and the voltage class and the current density can be rapidly distinguished or the electrified equipment and the power-off equipment can be distinguished.
(8) It is not clear how much the charged device is operating voltage, for verifying the operating voltage to prepare for the safety measures.
(9) It is not clear that the load of the charged equipment is too much, and the condition of the equipment for measurement cannot be accessed at will, and whether overload operation or short circuit fault occurs is diagnosed by remote measuring the load current.
Drawings
FIG. 1 is a schematic block diagram of an apparatus of the present invention;
FIG. 2 is a schematic diagram of embodiment 1;
FIG. 3 is a schematic diagram of embodiment 2;
FIG. 4 is a schematic diagram of the principle of example 3;
FIG. 5 is a diagram showing the relationship between the capacitor and the terminal voltage in embodiment 3.
Detailed Description
The technical solution of the present invention will be described in further detail with reference to the accompanying drawings, but the scope of the present invention is not limited to the following description.
As shown in FIG. 1, the non-contact type electric parameter measurement and verification device for the operation power equipment comprises a voltage acquisition module, a current acquisition module, an AD conversion module and a signal processing module;
the voltage acquisition module comprises a plurality of paths of voltage acquisition units, the current acquisition module comprises a current sensor coil, the current sensor coil and each path of voltage acquisition unit are used for acquiring tested power equipment, acquired information is respectively transmitted to the AD conversion module for conversion, the acquired signals are transmitted to the signal processing module, and the signal processing module is used for carrying out anomaly analysis on the tested equipment according to the information output by the AD conversion module.
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 unit and the current sensor coil.
In the embodiment of the application, the multipath voltage acquisition unit consists of one 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 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 an 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 as to facilitate the monitoring background to monitor or store.
S1, measuring the power equipment to be measured to obtain working voltage amplitude and phase angle;
S2, calculating a power factor angle and active power, and 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, and performing verification according to the average electric field intensity, and judging whether the detected power equipment has the conditions of exceeding the standard of radiation quantity, abnormal voltage, electric leakage and discharge;
s4, calculating the average charge quantity, and accordingly checking to judge whether the tested power equipment has a fault or not.
In an embodiment of the present application, the step S1 includes:
s101, enabling each measuring electrode to face a tested power device, and setting equivalent capacitance formed between each measuring electrode and a reference electrode as C1, C2 … Ck; each equivalent capacitor outputs a voltage measurement signal;
s102, carrying out AD conversion on voltage signals output by equivalent capacitors C1 and C2 … Ck, and carrying out Fourier transformation to obtain a voltage sequence V1 and V2 … Vk; the phase angles of the voltage sequences corresponding to the equivalent capacitors C1, C2 … Ck are respectively The phase angle sequence is a power frequency phase sequence obtained by performing Fourier or wavelet transformation on each voltage sequence V1, V2 … Vk respectively, and 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:
with the capacitances C1, C2 … Ck as X-axis, X > =0, and the voltages V1, V2 … Vk as Y-axis, Y > =0, the calculation method includes any one of the following:
a1, according to C1, C2 … Ck and corresponding V1, V2 … Vk, designing a straight line y=kx+k0 with a slope k smaller than 0, and calculating corresponding k0 as a voltage amplitude; when the capacitance C1, C2, ck and k >2, generating a plurality of straight lines, obtaining a plurality of k0 values, taking the average value of the k0 values as the k0 value, or arbitrarily taking two capacitances 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. -kx, and calculating corresponding k, wherein the value A is the voltage amplitude;
s104, according to the phase angle of C1, C2 … Ck and the corresponding voltage sequence Calculating a voltage phase angle:
with the capacitor C1, C2 … Ck as X-axis, X > =0, with phase angle For the Y axis, the calculation mode comprises any one of the following:
b1, according to C1, C2 … Ck and corresponding phase angles Designing a straight line y=kx+k0 with a slope k smaller than 0, and calculating a corresponding k0 as a voltage phase angle;
Similarly, when the capacitances C1, C2, ck, k >2, a plurality of straight lines are generated, a plurality of k0 values are obtained, and an average value of the plurality of k0 values is taken as the 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 And carrying out an exponential function y=A.e -kx, and calculating corresponding k and A, wherein the A value is the voltage phase angle.
In an embodiment of the present application, the step S2 includes:
the current amplitude and the phase of the current output by the current sensor coil are respectively I, The voltage amplitude and the voltage phase angle calculated in the step S1 are V,/>, respectively
Then calculate:
Apparent power s=v×i;
The power factor angle is:
Active power:
During verification, the tested device is considered to be abnormal when the apparent power or the active power exceeds a set threshold value.
Preferably, the step S3 includes:
s301, setting the distances from a measuring electrode to a reference electrode, which correspond to equivalent capacitors C1 and C2 … Ck, as d1 and d2 … dk;
S302, calculating the electric field intensity Ei corresponding to the equivalent capacitance Ci as follows:
Ei＝Vi/di-E0
wherein E0 is the stray ambient electric field strength, i=1, 2, …, k;
S303, repeatedly executing the step S302 when i=1, 2, … and k to obtain electric field strength sequences E1, E2, … and Ek;
s304, calculating average electric field strength E:
E＝(E1+E2+…+Ek)/k。
in the verification process, when the average field intensity is higher than a threshold, the radiation quantity of the tested power equipment is considered to exceed the standard, the voltage is abnormal or the electric leakage and discharge phenomena occur.
In an embodiment of the present application, the step S4 includes:
calculating an average charge quantity Q=E×r/beta-Q0, wherein beta is a constant, beta=9.0× 9, Q0 is a stray environmental charge, and E is an average electric field intensity; 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 the design value is exceeded, the tested power equipment is considered to be discharged, or the tested power equipment is considered to be inclined and the electric field is not uniform.
Obviously, when the average electric field intensity E and the electric charge amount Q are considered to be known stable amounts, the effective distance r between the tester and the tested electric power equipment can also be calculated according to the equivalent transformation of the above relation.
In an embodiment of the application, the method further comprises a measurement optimization step:
And after each measuring electrode is over against the measured power equipment, taking the electrode angle at the moment as a standard angle, adjusting the angle of the measuring electrode for a plurality of times on the premise that the difference between the angle and the standard angle is not more than plus or minus 15 degrees, measuring according to the steps S1-S4 after the standard angle and each adjustment respectively to obtain a plurality of groups of measuring data, and comparing the magnitude of the voltage amplitude in each group of measuring data, wherein one group of data with the largest voltage amplitude is taken as a final measuring result.
The application is further illustrated by the following examples:
Example 1, as shown in fig. 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 opening shape, an opening hook shape or a plane shape. The opening direction is aligned with the tested line or the tested device, or is aligned with or close to the tested device after being designed into a plane;
for convenience of description, the combination of the voltage sensing unit and the current sensing unit is referred to as a composite sensor.
Let us say that the 110kV power outage line is voltage-measured and typically this power outage line has no voltage. However, other nearby non-power-off lines will couple high voltage to the power-off line when power is off, so that the power-off line may be charged instantaneously, and if a detection tool is absent, an maintainer may get an electric shock. If the voltage is measured directly through the meter, the induced voltage can be released quickly because the ground of the meter is grounded, so that the detected induced voltage can be inaccurate in quantity, and the voltage can not be detected, but when the meter is removed from the power-off line, the power-off line can quickly recover the coupled voltage, and the human body gets an electric shock. And the instrument is in the measuring process, personnel are stressed and can touch the circuit carelessly to get an electric shock. After the device is adopted, the composite sensor is supported by the insulating rod to be aligned with the tested line, then the voltage and current output of the device are collected or indicated at the top of the insulating rod, and after the voltage sensing unit detects the voltage, the voltage sensing unit immediately gives an audible and visual alarm to remind a worker that the line is electrified at the moment.
Example 2, as shown in fig. 3, the voltage and current sensing units are placed opposite to each other to form a composite sensor with a through or open-close type;
similar to embodiment 1, the composite sensor can suspend or sleeve a circuit, can monitor the power factor, the current, the voltage and the power of the circuit in real time under the condition that the circuit is continuously electrified after being matched with the acquisition and communication device, and is particularly suitable for realizing real-time monitoring on the power factor abnormality, electricity stealing, short circuit, discharge and the like of a region and rapidly distinguishing the position where a fault occurs by arranging a plurality of monitoring devices on the circuit.
When the line is in power failure, if coupling voltage crosstalk exists, the composite sensor is matched with the voltage indication early warning device, whether the line is electrified or not can be indicated in real time through sound and light, and maintenance personnel are reminded to keep away.
Because no equipment contacts with the ground terminal in the electrified and power-off processes, the load of the circuit is not affected, and safety accidents such as ground short circuit and discharge are not caused.
Example 3, as shown in fig. 4, voltage measurement of the line was achieved by the sensor of this patent. A voltage sensor comprising a plurality of parallel rectangular coupling electrodes is shown in the following figure; the voltage sensor of the sensor is composed of a plurality of circular electrodes, and a plurality of capacitors in the vertical direction are formed by the voltage sensor, wherein voltage values output by the capacitors are collected by an analog-digital converter, and the voltage value corresponds to voltage V1, voltage V2 and voltage V3 when more electrodes exist in the voltage sensor, and the voltage sensor is similar to the voltage sensor. Obviously, the C1 capacitance is the smallest, the corresponding V1 is the highest, V2 is next, and V3 is again.
Calculating the voltage of the tested line through the exponential function y=A×e -kx, wherein x is a capacitance value, y is a capacitance end voltage value, and solving the equation to obtain the values A and k. The A value is the voltage value of the tested line.
If the calculation equation is a straight line, the equation is y=kx+k0, the required calculation is K0, and the straight line equation is shown by a dotted line, and the straight line is consistent with an exponential curve, and belongs to attenuation characteristics increasing along with capacitance.
As shown in fig. 5, whatever the equation is taken, the final calculation is the y value at x=0 on the curve described by the corresponding equation, namely: and a tangent distance value of the y axis.
The embodiment can finish high-voltage circuit and high-voltage equipment working voltage measurement by a ground worker, and can finish very accurate measurement effect by increasing the number of capacitors C.
Example 4: the data of example 3 was further modified.
The composite sensor is also internally provided with an inclination or inclination measuring unit. When the composite sensor is not exactly parallel to the tested line, the angle between the composite sensor and the tested line is used forMake corrective realizations, i.e./>Is realized by means of the method.
If further precision improvement is required, a plurality of compound sensors can be arranged, each compound sensor has a different angle, and then the calculated voltage values are compared to obtain an optimal value.
Or under the cooperative work of the analog-digital converter and the micro-processing, the calculated voltage value is output in real time and displayed. Then, by slightly adjusting the relative positions of the compound sensor and the tested line, and then observing the displayed voltage value, the maximum value is taken as the actual working voltage value of the tested device in principle.
Example 5: and (3) carrying out discharge test by using manual carrying aiming at the tested equipment, and observing whether the tested equipment discharges or not through voltage waveform jitter between different capacitances (capacitance between a measuring electrode and a reference electrode) in the voltage sensor. Or the multipath voltage acquisition units are designed into a penetrating structure and are directly clamped or sleeved on tested equipment, such as transformer bushings, cables, circuits, insulators and other equipment parts which are convenient to clamp, the internal digital processing module is utilized for measurement, signals are transmitted out through the communication module, and the receiving equipment observes or further calculates and diagnoses the signals.
Example 6: and (5) operating transformer transformation ratio and error measurement.
The non-contact electric parameter measurement verification devices of two sets of operation electric power equipment are adopted to synchronously measure the high-voltage side and the low-voltage side of the voltage transformer, the measured data calculation ratio is used as a voltage ratio, and the voltage ratio error can be calculated if the measured data calculation ratio is compared with a standard voltage transformation ratio.
The voltage phase difference of the high voltage side and the low voltage side can be used to calculate the voltage angle difference of the voltage transformer.
The same method, two sets of devices synchronously measure the primary current and the secondary current of the current transformer, the measured current ratio is used as the current ratio, and if the measured current ratio is compared with the standard current-transformation ratio, the current ratio error can be calculated.
The primary current value can be used as the current value of the current transformer to be measured by means of a correction method of the voltage acquisition unit, i.e. by means of an exponential function y=a× -kx or a linear function y=kx+k0 of the voltage measurement, the target current value y being obtained when x is zero. The specific model is completely referenced to the curve calculated by the parameters acquired by the voltage acquisition unit, but the measured current value is taken as a point on an exponential function or a linear function, and then the numerical value at x=0 is found along the curve as the 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 telemetry can be realized, and whether the wiring error of the circuit causes great transformation ratio deviation is checked based on the transformation ratio telemetry value; and the metering error of the transformer can be calculated, and whether serious ratio error or angle difference exists or not can be found.
Example 7: regional voltage imaging measurements.
The imaging measurement units are arranged in an 8 x 8 array, i.e. 64 composite sensor compositions are used. Each composite sensor comprises the multipath voltage sensors and the current sensors.
The whole electrode adopts a miniature printing film design, and the current sensor adopts a PCB printing coil design, so that the miniature sensor can be designed, and the whole array volume is reduced.
The number of the multipath voltage sensors included in each array element is set to be 3, and the current sensors are set to be 1, namely each array element has 4 paths of signal output. The 8×8 array has 64×4=256 outputs in total.
Analog quantity output of the array sensor is respectively connected with an analog-to-digital converter (ADC) with 256 channels, and synchronous 256-channel signal rapid acquisition is completed under the high-speed control of an 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, then a regional imaging algorithm is generated through a mathematical algorithm, or the calculated voltage imaging map is combined with a video through a combination of a graphic sensor (such as a camera), so that imaging of regional voltage class is formed.
Through this patent based on array element measuring imaging spectrum mode, can reach following effect at least:
(1) The voltage differences of the device groups are distinguished, such as the highest voltage device being identified as red and the lowest voltage as gray. The voltage difference in the equipment group can be clearly observed, such as 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 reactive compensation equipment, the primary and secondary equipment of the transformer and the like can be clearly observed in a 500kV transformer substation.
(2) The equipment can be verified to be electrified or powered off in a non-contact mode.
If the transmission line signal is weak, the interference after power failure is possible, and the fault is short-circuited, but the line is still electrified, so that the current of the tested equipment can be observed to be larger by means of the current sensing unit of the power transmission line signal detection device, 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-a multi-path voltage and 1-path current measurement unit, but imaging with array elements is more intuitive and easier to find short-circuit fault areas for environments in which multiple charged devices are operating).
(3) Rapidly finding out imbalance of three-phase voltage or three-phase current; or quickly find out a phase fault of the three-phase line.
Obviously, this patent scheme has all played very practical, positive effect to the safety inspection and the trouble shooting of lifting substation, outdoor overhead line, the electrified equipment in factory.
The scheme can be typically used for high-voltage lines, transformer substations, railway systems, energy storage stations, power stations and the like, can be used for rapidly identifying equipment with power and power failure, and can be used for rapidly identifying the equipment with different voltage levels.
For clarity of description, the above embodiments mainly use lines or cables, and in practice, the device of the present invention may be used for various kinds of live equipment, especially high voltage equipment, such as transformers, insulating bushings, GIS combined electrical appliances, transformers, insulators, lightning arresters, capacitors, switch cabinets, comprehensive field observations of multiple high voltage equipment, etc., and it preferably has a CT shape design with a through-core or open-close structure in terms of accurately measuring voltages, and multiple voltage measurement electrodes and current measurement coils are embedded in the CT inner ring, so as to facilitate shielding interference of other lines when measuring voltages and currents. In other occasions, the invention can be used for measurement and monitoring, and can also be used for checking equipment electrification, in particular for safety inspection, induction voltage early warning during maintenance and the like, and has good application value in the aspects of intelligent sensors, intelligent electric parameter measuring chips, high-precision and high-integration combined transformers, safety monitoring fields of circuits or power equipment, intelligent power equipment matched with precision sensors, voltage level imaging of substations or circuits, current density imaging sensors or test equipment.
Claims (8)
1. The utility model provides a non-contact electric parameter measurement verification device of operation power equipment 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 comprises a plurality of paths of voltage acquisition units, the current acquisition module comprises a current sensor coil, the current sensor coil and each path of voltage acquisition unit are used for acquiring tested power equipment, acquired information is respectively transmitted to the AD conversion module for conversion, the acquired signals are transmitted to the signal processing module, and the signal processing module is used for carrying out anomaly analysis on the tested equipment according to the information output by the AD conversion module;
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 voltage acquisition unit;
in each voltage acquisition unit, taking the voltage between the measuring electrode and the reference electrode as the output of the voltage acquisition unit;
The information acquisition, transmission and anomaly analysis processes of the tested power equipment are as follows:
setting the equivalent capacitance formed between each measuring electrode and the reference electrode as C1, C2 … Ck; each equivalent capacitor outputs a voltage measurement signal;
Performing AD conversion on voltage signals output by the equivalent capacitors C1 and C2 … Ck, and performing Fourier transformation to obtain a voltage sequence V1 and V2 … Vk;
The phase angles of the voltage sequences corresponding to the equivalent capacitors C1, C2 … Ck are respectively The phase angle sequences are power frequency phases obtained by performing Fourier or wavelet transformation on each voltage sequence V1, V2 … Vk respectively, and the power frequency refers to the working power frequency of the tested equipment;
from C1, C2 … Ck and the corresponding voltage sequences V1, V2 … Vk, the voltage amplitudes are calculated:
according to the phase angle of C1, C2 … Ck with the corresponding voltage sequence Calculating a voltage phase angle:
the current amplitude and the phase of the current output by the current sensor coil are respectively I, The voltage amplitude and the voltage phase angle calculated in the step S1 are V,/>, respectively
Then calculate:
Apparent power s=v×i;
The power factor angle is:
Active power:
During verification, the tested device is considered to be abnormal when the apparent power or the active power exceeds a set threshold value.
2. The non-contact electrical parameter measurement verification device for operating electrical equipment of claim 1, wherein: the AD conversion module comprises 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 unit and the current sensor coil.
3. A non-contact electrical parameter measurement and verification method for operating an electrical device, based on the measurement and verification device according to any one of claims 1 to 2, characterized in that: the method comprises the following steps:
S1, measuring the power equipment to be measured to obtain working voltage amplitude and phase angle;
S2, calculating a power factor angle and active power, and 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, and performing verification according to the average electric field intensity, and judging whether the detected power equipment has the conditions of exceeding the standard of radiation quantity, abnormal voltage, electric leakage and discharge;
s4, calculating the average charge quantity, and accordingly checking to judge whether the tested power equipment has a fault or not.
4. A non-contact electrical parameter measurement verification method for operating electrical equipment according to claim 3, wherein: the step S1 includes:
s101, enabling each measuring electrode to face a tested power device, and setting equivalent capacitance formed between each measuring electrode and a reference electrode as C1, C2 … Ck; each equivalent capacitor outputs a voltage measurement signal;
s102, carrying out AD conversion on voltage signals output by equivalent capacitors C1 and C2 … Ck, and carrying out Fourier transformation to obtain a voltage sequence V1 and V2 … Vk;
The phase angles of the voltage sequences corresponding to the equivalent capacitors C1, C2 … Ck are respectively The phase angle sequences are power frequency phases obtained by performing Fourier or wavelet transformation on each voltage sequence V1, V2 … Vk respectively, and 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:
with the capacitances C1, C2 … Ck as X-axis, X > =0, and the voltages V1, V2 … Vk as Y-axis, Y > =0, the calculation method includes any one of the following:
A1, according to C1, C2 … Ck and corresponding V1, V2 … Vk, designing a straight line y=kx+k0 with a slope k smaller than 0, and calculating corresponding k0 as a voltage amplitude;
When the capacitance C1, C2, ck and k >2, generating a plurality of straight lines, obtaining a plurality of k0 values, taking the average value of the k0 values as the k0 value, or arbitrarily taking two capacitances 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. -kx, and calculating corresponding k, wherein the value A is the voltage amplitude;
s104, according to the phase angle of C1, C2 … Ck and the corresponding voltage sequence Calculating a voltage phase angle:
with the capacitor C1, C2 … Ck as X-axis, X > =0, with phase angle For the Y axis, the calculation mode comprises any one of the following:
b1, according to C1, C2 … Ck and corresponding phase angles Designing a straight line y=kx+k0 with a slope k smaller than 0, and calculating a corresponding k0 as a voltage phase angle;
Similarly, when the capacitances C1, C2, ck, k >2, a plurality of straight lines are generated, a plurality of k0 values are obtained, and an average value of the plurality of k0 values is taken as the 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 And carrying out an exponential function y=A.e -kx, and calculating corresponding k and A, wherein the A value is the voltage phase angle.
5. A non-contact electrical parameter measurement verification method for operating electrical equipment according to claim 3, wherein: the step S2 includes:
the current amplitude and the phase of the current output by the current sensor coil are respectively I, The voltage amplitude and the voltage phase angle calculated in the step S1 are V,/>, respectively
Then calculate:
Apparent power s=v×i;
The power factor angle is:
Active power:
During verification, the tested device is considered to be abnormal when the apparent power or the active power exceeds a set threshold value.
6. A non-contact electrical parameter measurement verification method for operating electrical equipment according to claim 3, wherein: the step S3 includes:
s301, setting the distances from a measuring electrode to a reference electrode, which correspond to equivalent capacitors C1 and C2 … Ck, as d1 and d2 … dk;
S302, calculating the electric field intensity Ei corresponding to the equivalent capacitance Ci as follows:
Ei＝Vi/di-E0
wherein E0 is the stray ambient electric field strength, i=1, 2, …, k;
S303, repeatedly executing the step S302 when i=1, 2, … and k to obtain electric field strength sequences E1, E2, … and Ek;
s304, calculating average electric field strength E:
E＝(E1+E2+…+Ek)/k
in the verification process, when the average field intensity is higher than a threshold, the radiation quantity of the tested power equipment is considered to exceed the standard, the voltage is abnormal or the electric leakage and discharge phenomena occur.
7. A non-contact electrical parameter measurement verification method for operating electrical equipment according to claim 3, wherein: the step S4 includes:
calculating an average charge quantity Q=E×r/beta-Q0, wherein beta is a constant, beta=9.0× 9, Q0 is a stray environmental charge, and E is an average electric field intensity; 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 the design value is exceeded, the tested power equipment is considered to be discharged, or the tested power equipment is considered to be inclined and the electric field is not uniform.
8. A non-contact electrical parameter measurement verification method for operating electrical equipment according to claim 3, wherein: the method further comprises a measurement optimization step:
After each measuring electrode is opposite to the measured power equipment, the angle of the electrode at the moment is used as a standard angle, the angle of the measuring electrode is adjusted for multiple times on the premise that the difference between the angle and the standard angle is not more than plus or minus 15 degrees, and after the standard angle and each adjustment,
Measuring according to steps S1-S4 to obtain multiple groups of measurement data, comparing the voltage amplitude in each group of measurement data,
The set of data with the largest voltage step is taken as the final measurement result.
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