CN106932648B - Three-phase overhead transmission line phase voltage method for self-calibrating based on shunt capacitance - Google Patents
Three-phase overhead transmission line phase voltage method for self-calibrating based on shunt capacitance Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
- G01R27/2605—Measuring capacitance
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0084—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring voltage only
Abstract
Route is considered as a bulky capacitor with the earth and divided to it, using air as dielectric by a kind of method for self-calibrating of three-phase overhead transmission line phase voltage using space principle of capacitive divider.Fully consider all kinds of stray capacitances between three-phase line, including capacitor caused by insulating layer, capacitor present in alternate conducting wire etc. establishes lumped parameter equivalent circuit.In top crown side parallel switched capacitances, stray capacitance by changing its capacitance to change top crown to conducting wire, different voltage values will be measured on sampling capacitance, to extrapolate each unknown stray capacitance size and voltage swing to be measured, realizes the self calibration of three-phase line phase voltage.The present invention is suitable for the requirement of distribution distributed devices, is better than existing voltage measurement scheme.
Description
Technical field
It is aerial applied to the three-phase based on shunt capacitance in overhead line distributed electrical pressure sensor that the present invention relates to a kind of
Transmission line of electricity phase voltage method for self-calibrating.
Background technique
With the continuous development of China's power industry level, the developing direction that strong smart grid becomes following is built.
China's distribution network line has a large capacity and a wide range wire length at present, and local environment is complicated, high failure rate, developing low-cost distributed monitoring dress
It sets, realizes to the real time on-line monitoring and fault location for matching Running State to realization power distribution network high-efficiency and economic operation with great
Meaning.
It is a difficult point to the accurate measurement of the distribution of distribution network overhead line phase voltage.Now widely used voltage sensor
Device mainly has electromagnetic potential transformer (referred to as PT), capacitance type potential transformer (referred to as CVT), optical voltage sensor
Deng.Optical voltage sensor stability problem not yet solves very well, high-precision processing technology and technique for sticking is needed, not yet in electricity
Large-scale application is obtained in power mutual inductor.The capacity of conventional electromagnetic voltage transformer is smaller, at high cost, insulation system is complicated,
There are ferromagnetic resonance phenomenon, there is the influences of the factors such as leakage inductance distribution capacity, is not suitable with the demand of nowadays power grid gradually.Capacitive battery
Pressure mutual inductor is mainly used in 330kV or more power grid, and volume is big, involves great expense, not easy to install, is unable to satisfy inexpensive distribution
The requirement of device.Therefore a kind of phase voltage measurement method suitable for distribution distributed devices is established, and is able to achieve three-phase line
The contactless self calibration of phase voltage is of great significance to the voltage measurement accuracy for improving distributed devices.
Summary of the invention
It is an object of the invention to propose that a kind of three-phase overhead transmission line suitable for minimizing distributed devices is mutually electric
The method for self-calibrating of pressure overcomes the shortcomings of existing PT, CVT, optical voltage sensor, has high measurement accuracy.
The present invention utilizes space principle of capacitive divider, and transmission line of electricity and the earth are considered as voltage two-stage, will have pole up and down
The plane-parallel capacitor of plate is placed in one as sampling capacitance, fully considers all kinds of stray capacitances between three-phase line, including
Capacitor caused by insulating layer, capacitor present in alternate conducting wire etc., establishes lumped parameter equivalent circuit.In the parallel connection of top crown side
Switching capacity changes top crown to the miscellaneous of conducting wire by changing its capacitance
Spurious capacitance value will measure different voltage values on sampling capacitance, big so as to extrapolate each unknown stray capacitance
Voltage swing small and to be measured.
Technical solution of the invention is as follows:
A kind of three-phase overhead transmission line phase voltage method for self-calibrating based on shunt capacitance, it is characterized in that, this method
Include the following steps:
1) three distributed Voltage sensor surveying units are respectively placed in A, B, C tri- of three-phase overhead transmission line simultaneously
The output end of phase, the distributed Voltage sensor surveying unit is connected with computer, the distributed electrical pressure sensor
Measuring device is measured to one group of voltage measuring value UcA、UcB、UcC, and input computer and establish corresponding Calibration equation group (6):
Wherein, C11It is sampling capacitance top crown to the capacitor of this phase conductor；C12It is sampling capacitance to adjacent phase conductor capacitor；
C13Capacitor of the sampling capacitance to conducting wire, C between AC phasegFor the capacitor of sampling capacitance bottom crown over the ground, C is the appearance of sampling capacitance
Value；
2) in the sampling capacitance top crown of every phase distributed Voltage sensor surveying unit to the capacitor C11's of this phase conductor
Both ends are connected in parallel with a capacitor Ch, then it is equivalent to and changes C11For C '11=C11+Ch, measure to obtain one group of new voltage measuring value U 'cA,
U’cB,U’cC, it inputs computer and establishes another group of Calibration equation (7):
Wherein, C ' 11 is the equivalent sampling capacitor top crown after shunt capacitance Ch to the capacitor of this phase conductor；
3) in the sampling capacitance top crown of every phase distributed Voltage sensor surveying unit to the capacitor C11's of this phase conductor
Both ends are connected in parallel with a capacitor C againh, i.e. two capacitor C of the every both ends phase device C11 parallel connectionh,C″11=C11+2Ch, measured after in parallel
To third group voltage measuring value U "cA,U”cB,U”cC, and input computer and establish third group Calibration equation (8):
Wherein, C "11It is the equivalent sampling capacitor top crown after two capacitor Ch of parallel connection to the capacitor of this phase conductor；
4) (6) (7) (8) three groups of solving simultaneous equations are obtained C by computerg、C11、C12、C13、UA、UB、UC, that is, complete three
Phase overhead transmission line phase voltage self calibration.
The present invention due to use above technical scheme, fully consider all kinds of stray capacitances between three-phase line, including
Capacitor caused by insulating layer, capacitor present in alternate conducting wire etc., establishes lumped parameter equivalent circuit.In the parallel connection of top crown side
Switching capacity, the stray capacitance for changing top crown to conducting wire by changing its capacitance, will measure not on sampling capacitance
Same voltage value realizes three-phase line phase voltage so as to extrapolate each unknown stray capacitance size and voltage swing to be measured
Self calibration.
Detailed description of the invention
Fig. 1 is A phase device measurement equivalent circuit of the invention
Fig. 2 is B phase device of the invention, C phase device measurement equivalent circuit
Fig. 3 is parallel switched capacitances schematic diagram of the invention
Fig. 4 is the Optimization Solution convergence process schematic diagram of the embodiment of the present invention
Specific embodiment
It elaborates below in conjunction with drawings and examples to the present invention, but protection model of the invention should not be limited with this
It encloses.
Fig. 1, Fig. 2, Fig. 3 are first please referred to, Fig. 1 is A phase device measurement equivalent circuit of the invention, and Fig. 2 is B phase of the invention
Device, C phase device measure equivalent circuit, and Fig. 3 is parallel switched capacitances schematic diagram of the invention, as seen from the figure, the present invention is based on
The three-phase overhead transmission line phase voltage method for self-calibrating of shunt capacitance, this method include the following steps:
1) three distributed Voltage sensor surveying units are respectively placed in A, B, C tri- of three-phase overhead transmission line simultaneously
The output end of phase, the distributed Voltage sensor surveying unit is connected with computer, the distributed electrical pressure sensor
Measuring device is measured to one group of voltage measuring value UcA、UcB、UcC, and input computer and establish corresponding Calibration equation group (6):
Wherein, C11It is sampling capacitance top crown to the capacitor of this phase conductor；C12It is sampling capacitance to adjacent phase conductor capacitor；
C13Capacitor of the sampling capacitance to conducting wire, C between AC phasegFor the capacitor of sampling capacitance bottom crown over the ground, C is the appearance of sampling capacitance
Value；
2) in the sampling capacitance top crown of every phase distributed Voltage sensor surveying unit to the capacitor C of this phase conductor11Two
End is connected in parallel with a capacitor Ch, then it is equivalent to and changes C11For C '11=C11+Ch, measure to obtain one group of new voltage measuring value U 'cA,U’cB,
U’cC, it inputs computer and establishes another group of Calibration equation (7):
3) in the sampling capacitance top crown of every phase distributed Voltage sensor surveying unit to the capacitor C of this phase conductor11Two
End is connected in parallel with a capacitor C againh, i.e., every phase device C11Two capacitor C of both ends parallel connectionh,C″11=C11+2Ch, measure and obtain after in parallel
Third group voltage measuring value U "cA,U”cB,U”cC, and input computer and establish third group Calibration equation (8):
4) (6) (7) (8) three groups of solving simultaneous equations are obtained C by computerg、C11、C12、C13、UA、UB、UC, that is, complete three
Phase overhead transmission line phase voltage self calibration.
The principle of the present invention is as follows:
Since overhead transmission line is three-phase arrangement, distributed Voltage sensor surveying unit (hereinafter referred to as measuring device) is
Every phase is separately disposed, therefore every phase measuring device will be by remaining two-phase line influence when utilization space capacitance partial pressure measurement.With A
For phase, measurement equivalent circuit is as shown in Figure 1.It is calculated to simplify, wherein making following hypothesis: ABC three-phase voltage amplitude exists
To stablize constant in time of measuring, line conductor specification is identical, and phase spacing is identical, and the sampling capacitance of every phase measuring device is identical,
Distribution capacity is also identical over the ground.Wherein, C11It is sampling capacitance top crown to the capacitor of this phase conductor；C12It is sampling capacitance to neighbour
Phase conductor capacitor；C13Capacitor of the sampling capacitance to conducting wire between AC phase.Similarly, the equivalent circuit that B, C two-phase device measure is such as
Fig. 2
By taking Fig. 1 as an example, enabling 1 voltage of node is U, can be obtained by circuit theory:
Consider that sampling capacitance C can choose very big, reaches F grades of μ, it is believed that CgOver the ground for sampling capacitance bottom crown
Capacitor, then C+Cg≈ C, so
The then relationship of the voltage on sampling capacitance C and each phase voltage are as follows:
Wherein, UA,UB,UCThere is phase difference, it is assumed that phase difference perseverance is 120 ° between three-phase, then
UA=UA sin(ωt)UB=UB sin(ωt+240°)UC=UC sin(ωt+120°)
Above formula is substituted into, and carry out sinusoidal expansion to obtain:
Consider that calibration only need to calibrate amplitude or virtual value, then sinusoidal quantity can be omitted in above formula, retains amplitude, can obtain:
This is fundamental equation based on calibration, and similar equation can be obtained by being substituted into BC two-phase equivalent circuit in Fig. 2, therefore
Being extended to three-phase, can to obtain Calibration equation as follows:
Wherein, C11It is sampling capacitance top crown to the capacitor of this phase conductor, is mainly caused by insulating layer, C12For sampling electricity
Hold to adjacent phase conductor capacitor, C13Sampling capacitance is mainly caused the capacitor of conducting wire by air and insulating layer between AC phase；UA,
UB,UCFor three-phase voltage amplitude；CgFor the distribution capacity of sampling capacitance over the ground.Above 7 amounts are unknown quantity, need to calibrate and acquire.
C is the capacitance of sampling capacitance, is known quantity.UcA、UcB、UcCVoltage magnitude respectively is obtained measured by three-phase installation sampling capacitance,
For known quantity.
A kind of three-phase overhead transmission line phase voltage method for self-calibrating, its feature is as follows:
Calibration process is total to 7 unknown numerical quantities of demand, therefore required Calibration equation number should at least 7, according to equation group (6)
Obtained in Calibration equation number it is very few, equation number need to be increased.By the structure of analysis equation group (6) it may be concluded that changing
The value size of the capacitance known quantity C of sampling capacitance not can increase new effective equation number, need to change the size ability of unknown quantity
Increase new effective equation.C is given using shunt capacitance method according to the above thinking11Switching capacity known to parallel connection one, thus increase
New effective equation.In its schematic diagram such as Fig. 3, Fig. 3, in the switching capacity of the top crown side parallel connection known dimensions of sampling capacitance,
To change original C11, increase new effective equation.It can specifically realize as follows:
It is step 1, not in parallel, obtain one group of measured value UcA,UcB,UcC, it is (6) that this, which corresponds to Calibration equation,；
Step 2, every phase device C11 both ends be connected in parallel with a capacitor Ch, then it is equivalent to and changes C11Are as follows: C '11=C11+Ch, string
One group of new measured value U ' can be obtained after connectioncA,U’cB,U’cC, substitute into the Calibration equation (7) that can be obtained in equation (6) newly:
Two capacitor C of both ends parallel connection of step 3, every phase device C11h,C″11=C11+2Ch, can be obtained after in parallel one group it is new
Measured value U "cA,U”cB,U”cC, substitute into the Calibration equation (8) that can be obtained in equation (6) newly:
Therefore, (8) three groups of (6) (7) totally 9 equations can be obtained, wherein 7 unknown quantitys, need to only be solved by mathematical algorithm
Calibration is completed out.
To verify effectiveness of the invention, simulation model, three-phase measuring device peace have been built in software according to the present invention
Loaded on horizontally arranged three-phase line, line voltage distribution grade is 10kv.By known parameters by following value setting:
UcA=10.11 × 10-5kv UcB=10.12 × 10-5kv UcC=10.13 × 10-5kv
Uc′A=10.14 × 10-5kv U′cB=10.15 × 10-5kv U′cC=10.16 × 10-5kv
U″cA=10.17 × 10-5kv U″cB=10.18 × 10-5kv U″cC=10.19 × 10-5kv
C=100000pF=0.1 μ F
Ch=10pF
Using 9 Calibration equations of PSO PSO Algorithm.The tool box PSOt is added, pso_Trelea_ is called
Vectorized majorized function, number of parameters are set as n=7, and maximum particle rapidity takes the 10%:Max_V of parameter variation range
=0.1* (range (:, 2)-range (:, 1))
Optimum results are as follows:
| Unknown parameter | Numerical value |
| Cg | 0.653719923158255pF |
| C11 | 19.78549600195538pF |
| C12 | 13.147895102110086pF |
| C13 | 11.786300773633149pF |
| UA | 7.885691037742135kV |
| UB | 8.291756019856758kV |
| UC | 8.138569781222148kV |
Objective function convergence process is as shown in figure 4, solution procedure energy fast convergence.
In conclusion method for self-calibrating of the present invention can accurately solve unknown capacitance parameter and line voltage distribution, three-phase is realized
The self calibration of route phase voltage, effectively improves measurement accuracy.
Claims (1)
1. a kind of three-phase overhead transmission line phase voltage method for self-calibrating based on shunt capacitance, which is characterized in that this method packet
Include the following steps:
1) three distributed Voltage sensor surveying units are respectively placed in A, B, C three-phase of three-phase overhead transmission line simultaneously,
The output end of the distributed Voltage sensor surveying unit is connected with background computer, the distributed electrical pressure sensor
Measuring device is measured to one group of voltage measuring value UcA、UcB、UcC, and input computer and establish corresponding first group of Calibration equation group
(6):
Wherein, C11It is sampling capacitance top crown to the capacitor of this phase conductor；C12It is sampling capacitance to adjacent phase conductor capacitor；C13For
Capacitor of the sampling capacitance to conducting wire, C between AC phasegFor the capacitor of sampling capacitance bottom crown over the ground, C is the capacitor of sampling capacitance
Value；
2) in the sampling capacitance top crown of every phase distributed Voltage sensor surveying unit to the capacitor C of this phase conductor11Both ends are simultaneously
Join a capacitor Ch, then it is equivalent to and changes C11For C '11=C11+Ch, measure and obtain one group of new voltage measuring value U 'cA,U’cB,
U’cC, it inputs computer and establishes second group of Calibration equation (7):
Wherein, C '11It is the equivalent sampling capacitor top crown after shunt capacitance Ch to the capacitor of this phase conductor；
3) in the sampling capacitance top crown of every phase distributed Voltage sensor surveying unit to the capacitor C of this phase conductor11Both ends exist
C is connected in parallel with a capacitor on the basis of step 2) againh, i.e., every phase device C11Two capacitor C of both ends parallel connectionh, C "11=C11+2Ch, and
Measurement obtains third group voltage measuring value U " after connectioncA,U”cB,U”cC, and input computer and establish third group Calibration equation (8):
Wherein, C "11It is the equivalent sampling capacitor top crown after two capacitor Ch of parallel connection to the capacitor of this phase conductor；
4) computer is square by first group of Calibration equation group (6), second group of Calibration equation group (7) and third group Calibration equation group (8)
Cheng Lianli is solved using optimization algorithm, obtains Cg、C11、C12、C13、UA、UB、UC, that is, complete three-phase overhead transmission line phase voltage
Self calibration.
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| CN109582071B (en) * | 2017-09-29 | 2020-10-27 | 北京金风科创风电设备有限公司 | Bus voltage calibration method and apparatus, and computer-readable storage medium |
| CN110221237A (en) * | 2019-06-27 | 2019-09-10 | 广东工业大学 | A kind of capacitance type potential transformer harmonic voltage measurement method and apparatus |
| CN114296020B (en) * | 2021-11-23 | 2024-04-16 | 国网河北省电力有限公司电力科学研究院 | Fault simulation device and simulation method for capacitive voltage transformer |
| CN115267301B (en) | 2022-09-30 | 2023-01-20 | 南方电网数字电网研究院有限公司 | Voltage measuring method, voltage measuring device, computer equipment and storage medium |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7123032B2 (en) * | 2003-12-04 | 2006-10-17 | Fieldmetrics, Inc. | Voltage sensor and dielectric material |
| CN102116807A (en) * | 2010-12-29 | 2011-07-06 | 重庆大学 | Three-dimensional power frequency electric field measurement method and device capable of correcting distortion of electric field |
| EP2684105A1 (en) * | 2011-03-09 | 2014-01-15 | Petra Solar Inc. | Distributed control of dynamic reactive power |
| CN204992783U (en) * | 2015-10-05 | 2016-01-20 | 程文硕 | Distributing type electric power monitored control system |
| CN204992780U (en) * | 2015-10-05 | 2016-01-20 | 赵欣 | Distributing type electric power detecting system |
| CN205004756U (en) * | 2015-05-27 | 2016-01-27 | 周皓 | Control device of three -phase photovoltaic grid -connected inverter |
-
2017
- 2017-02-28 CN CN201710114039.XA patent/CN106932648B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7123032B2 (en) * | 2003-12-04 | 2006-10-17 | Fieldmetrics, Inc. | Voltage sensor and dielectric material |
| CN102116807A (en) * | 2010-12-29 | 2011-07-06 | 重庆大学 | Three-dimensional power frequency electric field measurement method and device capable of correcting distortion of electric field |
| EP2684105A1 (en) * | 2011-03-09 | 2014-01-15 | Petra Solar Inc. | Distributed control of dynamic reactive power |
| CN205004756U (en) * | 2015-05-27 | 2016-01-27 | 周皓 | Control device of three -phase photovoltaic grid -connected inverter |
| CN204992783U (en) * | 2015-10-05 | 2016-01-20 | 程文硕 | Distributing type electric power monitored control system |
| CN204992780U (en) * | 2015-10-05 | 2016-01-20 | 赵欣 | Distributing type electric power detecting system |
Non-Patent Citations (1)
| Title |
|---|
| "基于电容分压法的配网线路智能电压传感器";谢潇磊;《仪器仪表学报》;20160531;第37卷(第5期);1000-1008 |
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