CN202975173U - Ground capacitance measuring instrument in transformer substation power distribution system - Google Patents
Ground capacitance measuring instrument in transformer substation power distribution system Download PDFInfo
- Publication number
- CN202975173U CN202975173U CN2012206102132U CN201220610213U CN202975173U CN 202975173 U CN202975173 U CN 202975173U CN 2012206102132 U CN2012206102132 U CN 2012206102132U CN 201220610213 U CN201220610213 U CN 201220610213U CN 202975173 U CN202975173 U CN 202975173U
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- signal
- ground capacitance
- bridge inverter
- master controller
- inverter circuit
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/08—Limitation or suppression of earth fault currents, e.g. Petersen coil
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- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
The utility model discloses a ground capacitance measuring instrument in a transformer substation power distribution system. The instrument comprises a signal acquisition device, a main controller and an H bridge inverter circuit, wherein the signal acquisition device is used to collect current and voltage signals in an arc suppression coil; the main controller possesses control, analysis and operation functions; the H bridge inverter circuit is used to provide a conversion current signal for a power grid. The signal acquisition device, the main controller and the H bridge inverter circuit are successively connected. An input terminal of the signal acquisition device and an output terminal of the H bridge inverter circuit are connected to a power grid arc suppression coil grounding device. Compared to a traditional single phase metal grounding method, by using the instrument of the utility model, a grounding fault does not need to be made on purpose and a system risk is avoided; aiming at a near resonant point operation mode in which a damping resistor is additionally installed and a far away resonant point operation mode in which the damping resistor is not additionally installed of the current arc suppression coil, two different measuring modes of a two-point method and a frequency conversion method are designed respectively. System ground capacitance measuring precision is guaranteed and negative effects are not brought to the system simultaneously.
Description
Technical field
The utility model relates to the ground capacitance measuring instrument in a kind of transformer station distribution system.
Background technology
When electrical network generation singlephase earth fault, the inductive current that adopts grounding through arc can utilize arc suppression coil to produce has compensated the earth point capacitance current, has reduced the fault phase voltage recovery rate, makes earth point electric arc automatic distinguishing.Therefore, accurate measuring systems ground capacitance value be the correct inductive current of arc suppression coil generation, thereby compensation of ground point capacitance current makes earth point electric arc automatic distinguishing, the essential condition that remaining ground current is less.The measurement of traditional capacitance electric current is mainly the Single Phase Metal earthing.This method can directly be measured the meritorious and idle component of offset current, active loss electric current and the aftercurrent of arc suppression coil, thereby draw capacitance current under the condition that arc suppression coil puts into operation.The problem that this method exists is, deliberately makes earth fault, increases system risk, if the earth fault of other phases occurs when measuring, can develop into very harmful phase fault, so this method is also inapplicable in practice.
The utility model content
For addressing the above problem, the purpose of this utility model is to provide a kind of ground capacitance surveying instrument that is applied in transformer station's distribution system, need not deliberately to make earth fault, avoids system risk.
The technical scheme that the invention for solving the technical problem adopts is:
Ground capacitance measuring instrument in a kind of transformer station distribution system, comprise signal pickup assembly for the electric current that gathers arc suppression coil and voltage signal, have and control and the master controller of analytic operation function, be used for providing to electrical network the H bridge inverter circuit of change of current signal, described signal pickup assembly, master controller, H bridge inverter circuit are connected successively, and the output terminal of the input end of wherein said signal pickup assembly, H bridge inverter circuit is connected in electric wire netting arc extinguishing coil earthing device.For present arc suppression coil the close tuning-points operational mode that installs damping resistance additional is arranged and do not add damping resistance away from the tuning-points operational mode, master controller of the present utility model can adopt respectively according to the operational mode of arc suppression coil two kinds of metering systems of two-point method and frequency variation method to measure ground capacitance.The utility model selects dsp chip as master controller, complete and detect and control algolithm, and produce the gating pulse PWM waveform that acts on the H bridge inverter circuit, and inject the sinusoidal ac signal of power frequency and frequency conversion to system, realize that respectively the ground capacitance of two-point method and frequency variation method is measured.
Further, described signal pickup assembly comprises sensor circuit for detection of voltage and current signal, is used for is the signal conditioning circuit of digital signal with analog-signal transitions, the output terminal of described sensor circuit is connected in the input end of signal conditioning circuit, the input end of described sensor circuit is connected in electric wire netting arc extinguishing coil earthing device, and the output terminal of described signal conditioning circuit is connected in master controller.Described sensor circuit comprises the voltage transformer (VT) summation current transformer, voltage, current signal for detection of arc suppression coil, described signal is transformed to simulating signal to calculate for data acquisition, control procedure, execution through signal processing circuit and shows and read or the digital signal of other purposes, through carrying out analytic operation in the input of the signal after D/A switch master controller.
As improvement of the technical scheme, described master controller is connected with for the watchdog chip that guarantees system stable operation.Described watchdog chip is used for the running status of monitoring master controller chip, when the system crash situations such as the race of master controller chip generating program flies, endless loop, watchdog chip just it with pin that master controller chip reset pin is connected on send a reset signal, make the master controller chip reset.
As improvement of the technical scheme, also comprise liquid crystal keyboard for parameters, be used for the display measurement data display device, be used for printing measurement data printer, have the warning device of fault alarm function, described liquid crystal keyboard, display device, printer, warning device are connected with master controller respectively.Described liquid crystal keyboard, display device, printer, warning device have realized that the man-machine interface of system realizes monitoring, parameter setting, warning, demonstration and printing, and automaticity is high.
The beneficial effects of the utility model are: a kind of ground capacitance surveying instrument that is applied in transformer station's distribution system that the utility model adopts, compare traditional Single Phase Metal earthing, and need not deliberately to make earth fault, avoid system risk.And for present arc suppression coil the close tuning-points operational mode that installs damping resistance additional is arranged and do not add damping resistance away from the tuning-points operational mode, design respectively two kinds of different measuring modes of two-point method and frequency variation method.The utility model had both guaranteed system's ground capacitance measuring accuracy, can not bring negative effect to system simultaneously.
Description of drawings
The utility model is described in further detail below in conjunction with accompanying drawing and example.
Fig. 1 is fundamental diagram of the present utility model.
Fig. 2 is the topological diagram of the utility model primary structure.
Embodiment
See figures.1.and.2, ground capacitance measuring instrument in a kind of transformer station of the present utility model distribution system, comprise signal pickup assembly 1 for the electric current that gathers arc suppression coil and voltage signal, have and control and the master controller 2 of analytic operation function, be used for providing to electrical network the H bridge inverter circuit 3 of change of current signal, described signal pickup assembly 1, master controller 2, H bridge inverter circuit 3 are connected successively, and the output terminal of the input end of wherein said signal pickup assembly 1, H bridge inverter circuit 3 is connected in electric wire netting arc extinguishing coil earthing device 4.For present arc suppression coil the close tuning-points operational mode that installs damping resistance additional is arranged and do not add damping resistance away from the tuning-points operational mode, master controller 2 of the present utility model can adopt respectively according to the operational mode of arc suppression coil the different metering systems of two kinds of two-point method and frequency variation methods to measure ground capacitance.The utility model selects dsp chip as master controller 2, complete and detect and control algolithm, and produce the gating pulse PWM waveform that acts on H bridge inverter circuit 3, and inject the sinusoidal ac signal of power frequency and frequency conversion to system, realize that respectively the ground capacitance of two-point method and frequency variation method is measured.
Further, described signal pickup assembly 1 comprises sensor circuit 11 for detection of voltage and current signal, is used for is the signal conditioning circuit 12 of digital signal with analog-signal transitions, the output terminal of described sensor circuit 11 is connected in the input end of signal conditioning circuit 12, the input end of described sensor circuit 11 is connected in electric wire netting arc extinguishing coil earthing device 4, and the output terminal of described signal conditioning circuit 12 is connected in master controller 2.Described sensor circuit 11 comprises the voltage transformer (VT) summation current transformer, voltage, current signal for detection of arc suppression coil, described signal is transformed to simulating signal to calculate for data acquisition, control procedure, execution through signal processing circuit 12 and shows and read or the digital signal of other purposes, through carrying out analytic operation in the input of the signal after D/A switch master controller 2.
As improvement of the technical scheme, described master controller 2 is connected with for the watchdog chip 5 that guarantees system stable operation.Described watchdog chip 5 is used for the running status of monitoring master controller chip, when the system crash situations such as the race of master controller chip generating program flies, endless loop, watchdog chip 5 just it with pin that master controller chip reset pin is connected on send a reset signal, make the master controller chip reset.
As improvement of the technical scheme, also comprise liquid crystal keyboard 6 for parameters, be used for the display measurement data display device 7, be used for printing measurement data printer 8, have the warning device 9 of fault alarm function, described liquid crystal keyboard 6, display device 7, printer 8, warning device 9 are connected with master controller 2 respectively.Described liquid crystal keyboard 6, display device 7, printer 8, warning device 9 have realized that the man-machine interface of system realizes monitoring, parameter setting, warning, demonstration and printing, and automaticity is high.
The concrete course of work of the utility model is: judge that first arc suppression coil is near tuning-points or moves away from tuning-points, after selecting respectively two-point method and frequency variation method, then trigger H bridge inverter circuit 3 output current signals by master controller 2 PWM waveforms corresponding to output.
During two-point method measuring and calculating electric capacity, first gather amplitude and the phase place of neutral point voltage, electric current, obtain U1, I1, PhiU1, PhiI1.Then trigger H bridge inverter circuit 3, inject amplitude 5A, the electric current of 50Hz gathers amplitude and the phase place of neutral point voltage, electric current again after time-delay 1s, obtain U2, I2, PhiU2, PhiI2.Then calculate capacitor C and capacitive reactance X
CAs follows:
In formula, two phasors are subtracted each other with the cosine law and are calculated:
Under frequency modulation method pattern, current amplitude of H bridge inverter circuit 3 outputs is constant, frequency is at the signal of 10～50Hz with the continuous increase of fixed step size electric current, the relation of electric current and voltage signal when survey frequency changes, when current value amplitude maximum, voltage magnitude hour, respective frequencies is the resonance frequency of system, obtains the resonance angular frequency of system
, the capacitance C of system and capacitive reactance X
CAs follows:
In formula,
Be the electric system natural angular frequency
, L is the inductance value of arc suppression coil.
Select two-point method and frequency variation method different measuring mode, can better adapt to arc suppression coil the close tuning-points operational mode that installs damping resistance additional is arranged and do not add damping resistance away from the tuning-points operational mode.When damping resistance was arranged, the current signal amplitude was 5A, can guarantee to be subjected to the signal after the system damping rate decays can not have influence on measuring accuracy; When there is no damping resistance, the current signal amplitude is 0.5A, when tuning-points moves, can not cause higher resonance potential.Like this, during apparatus measures, both guarantee system's ground capacitance measuring accuracy, and can not bring negative effect to system simultaneously.
The above is preferred embodiment of the present utility model, and the utility model is not limited to above-mentioned embodiment, as long as it reaches technique effect of the present utility model with identical means, all should belong to protection domain of the present utility model.
Claims (4)
1. the ground capacitance measuring instrument in transformer station's distribution system, it is characterized in that: comprise signal pickup assembly (1) for the electric current that gathers arc suppression coil and voltage signal, have and control and the master controller (2) of analytic operation function, be used for providing to electrical network the H bridge inverter circuit (3) of change of current signal, described signal pickup assembly (1), master controller (2), H bridge inverter circuit (3) are connected successively, and the output terminal of the input end of wherein said signal pickup assembly (1), H bridge inverter circuit (3) is connected in electric wire netting arc extinguishing coil earthing device (4).
2. the ground capacitance measuring instrument in a kind of transformer station according to claim 1 distribution system, it is characterized in that: described signal pickup assembly (1) comprises the sensor circuit (11) for detection of voltage and current signal, being used for is the signal conditioning circuit (12) of digital signal with analog-signal transitions, the output terminal of described sensor circuit (11) is connected in the input end of signal conditioning circuit (12), the input end of described sensor circuit (11) is connected in electric wire netting arc extinguishing coil earthing device (4), the output terminal of described signal conditioning circuit (12) is connected in master controller (2).
3. the ground capacitance measuring instrument in a kind of transformer station according to claim 1 distribution system, it is characterized in that: described master controller (2) is connected with for the watchdog chip (5) that guarantees system stable operation.
4. the ground capacitance measuring instrument in a kind of transformer station according to claim 1 distribution system, it is characterized in that: also comprise liquid crystal keyboard (6) for parameters, be used for the display measurement data display device (7), be used for printing measurement data printer (8), have the warning device (9) of fault alarm function, described liquid crystal keyboard (6), display device (7), printer (8), warning device (9) are connected with master controller (2) respectively.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012206102132U CN202975173U (en) | 2012-11-16 | 2012-11-16 | Ground capacitance measuring instrument in transformer substation power distribution system |
| CN201210462322.9A CN102981061B (en) | 2012-11-16 | 2012-11-16 | Direct-to-ground capacitance measuring instrument in a kind of transformer station distribution system |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012206102132U CN202975173U (en) | 2012-11-16 | 2012-11-16 | Ground capacitance measuring instrument in transformer substation power distribution system |
| CN201210462322.9A CN102981061B (en) | 2012-11-16 | 2012-11-16 | Direct-to-ground capacitance measuring instrument in a kind of transformer station distribution system |
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| CN202975173U true CN202975173U (en) | 2013-06-05 |
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| CN201210462322.9A Expired - Fee Related CN102981061B (en) | 2012-11-16 | 2012-11-16 | Direct-to-ground capacitance measuring instrument in a kind of transformer station distribution system |
| CN2012206102132U Expired - Fee Related CN202975173U (en) | 2012-11-16 | 2012-11-16 | Ground capacitance measuring instrument in transformer substation power distribution system |
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| CN201210462322.9A Expired - Fee Related CN102981061B (en) | 2012-11-16 | 2012-11-16 | Direct-to-ground capacitance measuring instrument in a kind of transformer station distribution system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102981061A (en) * | 2012-11-16 | 2013-03-20 | 广东中钰科技有限公司 | Direct earth capacitance gauge in converting station power distribution system |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103280793B (en) * | 2013-04-17 | 2016-04-27 | 河北旭辉电气股份有限公司 | Based on the electrical network earthing compensation device of arc suppression transformer |
| CN103675469B (en) * | 2013-12-31 | 2016-04-13 | 西安兴汇电力科技有限公司 | A kind of high-tension line distributed capacitance measurement mechanism and measuring method thereof |
| CN104917169B (en) * | 2015-07-10 | 2017-07-18 | 山东大学 | Capacitive current measuring method for neutral by arc extinction coil grounding system |
| CN111289802B (en) * | 2020-01-10 | 2023-05-30 | 中国石油大学(华东) | Method for measuring capacitance current to ground of resonant grounding system |
| CN113341246B (en) * | 2021-05-24 | 2024-02-06 | 国网陕西省电力公司西安供电公司 | Arc suppression coil testing device and method based on capacitance calibration |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP3094246B2 (en) * | 1991-08-30 | 2000-10-03 | 豊 西村 | Capacitance measurement method |
| AT402770B (en) * | 1995-04-25 | 1997-08-25 | Haefely Trench Austria Gmbh | METHOD FOR MONITORING A THREE-PHASE NETWORK FOR A CHANGE IN THE TUNING COOLER |
| JP2002082724A (en) * | 2000-09-06 | 2002-03-22 | Meidensha Corp | Load inductance measuring method and semiconductor electric power converting device |
| CN1216294C (en) * | 2002-07-03 | 2005-08-24 | 广州智光电气有限公司 | Method for testing single phase grounding current of electric power network |
| CN100507583C (en) * | 2007-03-16 | 2009-07-01 | 长沙理工大学 | Distribution network earth insulation parameter measuring and controlling method |
| CN101937024A (en) * | 2010-08-04 | 2011-01-05 | 济南奥诺数控设备有限公司 | Capacitance measurement method and measurement device for power distribution network with neutral point grounded through arc suppression coil |
| CN102004191A (en) * | 2010-09-29 | 2011-04-06 | 思源电气股份有限公司 | Method for calculating line capacitance in arc suppression coil parallel running system |
| CN102981061B (en) * | 2012-11-16 | 2016-05-18 | 广东中钰科技股份有限公司 | Direct-to-ground capacitance measuring instrument in a kind of transformer station distribution system |
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2012
- 2012-11-16 CN CN201210462322.9A patent/CN102981061B/en not_active Expired - Fee Related
- 2012-11-16 CN CN2012206102132U patent/CN202975173U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102981061A (en) * | 2012-11-16 | 2013-03-20 | 广东中钰科技有限公司 | Direct earth capacitance gauge in converting station power distribution system |
| CN102981061B (en) * | 2012-11-16 | 2016-05-18 | 广东中钰科技股份有限公司 | Direct-to-ground capacitance measuring instrument in a kind of transformer station distribution system |
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| Publication number | Publication date |
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| CN102981061A (en) | 2013-03-20 |
| CN102981061B (en) | 2016-05-18 |
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Legal Events
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee |
Owner name: GUANGDONG ZHONGYU TECHNOLOGY CO., LTD. Free format text: FORMER NAME: ZHONGYU SCIENCE + TECHNOLOGY CO., LTD., GUANGDONG |
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| CP03 | Change of name, title or address |
Address after: 511495 Guangdong city of Guangzhou province Panyu District zhongcunzhen Pingshan Village (office building No. 2) Patentee after: GUANGDONG ZHONGYU TECHNOLOGY CO., LTD. Address before: A street in Guangdong city of Guangzhou province Panyu District 511495 cliff Street Xinghong Patentee before: Zhongyu Science & Technology Co., Ltd., Guangdong |
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130605 Termination date: 20171116 |
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| CF01 | Termination of patent right due to non-payment of annual fee |