CN101256205A - Instrument for measuring and recording mutation current of neutral point earthing resistor - Google Patents
Instrument for measuring and recording mutation current of neutral point earthing resistor Download PDFInfo
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- CN101256205A CN101256205A CNA2007100377084A CN200710037708A CN101256205A CN 101256205 A CN101256205 A CN 101256205A CN A2007100377084 A CNA2007100377084 A CN A2007100377084A CN 200710037708 A CN200710037708 A CN 200710037708A CN 101256205 A CN101256205 A CN 101256205A
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Abstract
The invention provides a neutral resistance mutation circuit measuring and recording device, comprising a shell provided with an operation panel and a plurality of connection terminals, and a mutual inductor in the shell and connected with the corresponding connection terminal and a measuring and recording system in the shell and composed of a central processing unit and input module, output module, data storage device, signal sampling module, communication module and clock and load-loss memory module respectively connected with the central processing unit. The neutral resistance mutation circuit measuring and recording device can monitor the work condition of ground resistance and three-phase equilibrium of power utilization network and failure condition, therefore the ground resistance is ensured run at good state and record data to provide reference for fault analysis and play important action for normal operation and routine maintenance of ground resistance of transformer substation. At the same time the cost of measuring and recording device is low, so that the measuring and recording device can be widely mounted on the transformer substation of 35 kilovolt.
Description
Technical field
The present invention relates to a kind of electric current instrument for measuring and recording, relate in particular to the neutral resistance instrument for measuring and recording mutation current of a kind of central point through the distribution network system of resistance eutral grounding.
Technical background
In electric system, earthing mode mainly contains resistance eutral grounding, resonance grounding and earth-free these several earthing modes.Along with improving constantly of cable rate in the electrical network, system capacitive current increases gradually, and resistance earthing has obtained application more and more widely.The resistance quantity that neutral ground is used also increases thereupon, and operating mode how to control stake resistance becomes the problem that needs are paid attention to.
Along with the using and updating of stake resistance, to electric resistance of stainless, arrive combined type resistance cabinet from cast iron resistance again, but do not obtain paying attention to always for the operating mode control of stake resistance.Because stake resistance has only when single-phase earthing occurring in the electrical network at the normal system voltage that do not bear in service, just bears system voltage.Therefore it is generally acknowledged that stake resistance itself does not need to protect or monitor.The neutral resistance fault flows through the electric current of neutral resistance except quality of resistance own and structure problem, be the factor that the stake resistance operating mode is had the greatest impact.
Because the ground protection setting time in the system all was controlled in 4.5 seconds, the thermally-stabilised accounting of stake resistance is generally according to 10 seconds 1000 peaces.Stake resistance relevant criterion and type approval test at present all set up on this basis.Usually do not consider that ground current for a long time by stake resistance, not take monitoring measure at this situation.
It has been generally acknowledged that single-phase earthing in resistance grounded system, can start zero-sequence current or zero-sequence voltage protection, thereby therefore the excision fault can not exert an influence to stake resistance.But in actual conditions, because various situations may cause the ground connection of intermittent ground connection and big resistance transition resistance, for example the insulated conductor broken string causes intermittent ground connection easily, and cable splice ground connection in worker's well causes big resistance transition resistance ground connection easily.For big resistance transition resistance ground connection, because reaching, fault current numerical value protects the requirement of adjusting, may cause to protect and be failure to actuate; For intermittent ground connection, because twice clearance gap time is shorter, be not enough to start protection, also can cause to protect and be failure to actuate.These two kinds of earth faults all might cause neutral resistance for a long time by electric current, so that shorten the operation life of stake resistance, even produce the stake resistance fault.The stake resistance fault of Chan Shenging is huge for the influence of system in this case.Because in this case; protection action and signal alarm do not have only when fault further develops just to start protection action or signal alarm, and promptly might there be fault for a long time in system; and then the expansion fault, can cause tremendous influence to total system.
Neutral resistor since its operation characteristic promptly at the normal system voltage that do not bear in service, therefore for the judgement of neutral resistance health status, the prerun the when equipment that mainly depends on stops using as a servant.For the stake resistance under running status, except methods such as seeing, listen, look, smell by tour personnel employing, also require after singlephase earth fault occurring, stake resistance is carried out infrared imaging detect.These means are general to be that neutral resistor is not flowed through and carried out under the situation of electric current in system's normal condition only all, for not reaching the ground connection situation that starts setting valve, can't play effect.
Summary of the invention
The objective of the invention is provides a kind of neutral resistance instrument for measuring and recording mutation current for overcoming above shortcoming, this side record instrument can monitoring grounding resistance working condition and monitor three-phase equilibrium degree and each failure condition relatively of power utilization network, guarantee that stake resistance moves with good state, and can provide foundation for fault analysis by record data.
The technical scheme that realizes above-mentioned purpose is: a kind of neutral resistance instrument for measuring and recording mutation current, comprise that one is provided with the housing of guidance panel and some connection terminals, and be positioned at the mutual inductor that housing links to each other with corresponding wiring terminal, wherein, also be provided with one in the described housing and survey recording system, this survey recording system comprises a central processing unit, and the load module that links to each other with this central processing unit respectively, output module, data-carrier store, signal sampling module, communication module and clock and dead electricity memory module, wherein:
Described signal sampling module receives from the voltage of mutual inductor or current output signal as its input signal, then this signal is exported to central processing unit after treatment;
Described load module receives from the input signal on the guidance panel, exports it to central processing unit then;
Described output module receives from central processing unit output signal after treatment, and with its demonstration and warning.
Above-mentioned a kind of neutral resistance instrument for measuring and recording mutation current, wherein, described signal sampling module comprises a signal condition filtering submodule and the A/D conversion submodule that links to each other with this submodule, this signal condition filtering submodule is receiving inputted signal at first, exports central processing unit through nursing one's health filtered signal to by A/D conversion submodule.
Above-mentioned a kind of neutral resistance instrument for measuring and recording mutation current, wherein, described output module comprises output alarm submodule and the display sub-module that an output power is amplified submodule and is attached thereto, and output power is amplified submodule will export to output alarm submodule and display sub-module after the signal amplification after treatment from central processing unit.
Above-mentioned a kind of neutral resistance instrument for measuring and recording mutation current, wherein, described communication module comprises that a communication switches chooser module and some communication mode submodules that is attached thereto, communication switch the different communication mode submodule of the changeable selection of chooser module so that system works under different communication modes.
Above-mentioned a kind of neutral resistance instrument for measuring and recording mutation current, wherein, described communication mode submodule comprises RS485 communication mode submodule and/or RS232 communication mode submodule and/or GSM communication mode submodule and/or infrared communication pattern submodule.
Above-mentioned a kind of neutral resistance instrument for measuring and recording mutation current, wherein, described load module adopts the mode of keyboard input.
Above-mentioned a kind of neutral resistance instrument for measuring and recording mutation current, wherein, described mutual inductor is current transformer and voltage transformer (VT).
Above-mentioned a kind of neutral resistance instrument for measuring and recording mutation current wherein, also is provided with the connection terminal between the current input terminal of described current transformer and signal sampling module.
Above-mentioned a kind of neutral resistance instrument for measuring and recording mutation current, wherein, described mutual inductor adopts the amorphous alloy material coiling to form.
Above-mentioned a kind of neutral resistance instrument for measuring and recording mutation current, wherein, described data-carrier store adopts Serial E
2Prom memory.
The invention has the beneficial effects as follows: a kind of neutral resistance instrument for measuring and recording mutation current of the present invention is by the current sample (also can sample to residual voltage) to the neutral resistor of flowing through, the duty of monitoring grounding resistance, each failure condition relatively, guarantee that stake resistance moves with good state, start the instrument for measuring and recording record data by zero-sequence current (also can pass through residual voltage), help catching the abnormal conditions with analytic system, the normal operation and the daily servicing of substation grounding resistance played vital role.Because this side record instrument price is comparatively cheap, can generally be installed in 35 kv substations simultaneously.
Description of drawings
Fig. 1 is the system chart of a kind of neutral resistance instrument for measuring and recording mutation current of the present invention.
Embodiment
Below in conjunction with accompanying drawing a kind of neutral resistance instrument for measuring and recording mutation current of the present invention is described further.
See also Fig. 1, there is shown a kind of neutral resistance instrument for measuring and recording mutation current of the present invention, it comprises a housing (not shown) that is provided with guidance panel and some connection terminals, be positioned at one of mutual inductor (not shown) that housing links to each other with corresponding wiring terminal and housing (not shown) surveys recording system.
Survey recording system comprise a high-speed computation, crystal oscillator frequency reaches the central processing unit 1 of 22MHZ, and load module 3, output module 5, data-carrier store 4, signal sampling module 2, communication module 7 and the clock and the dead electricity memory module 6 that link to each other with this central processing unit 1 respectively, wherein:
Data-carrier store 4 adopts Serial E 2PROM storeies (can online electricity wiping the storer with electronically written), and reliability height, power consumption are little, need not backup battery, also can keep data during dead electricity;
Clock and dead electricity memory module 6 have adopted a SD2001CPI chip, it provides clock signal and synchronizing signal as system, this chip can provide high-precision calendar and time and timer clock and interruption pulse, the RAM storer (random access memory) of some energy loss protecting data;
Mutual inductor in the present embodiment adopts the amorphous alloy material coiling to form, comprise current transformer (not shown) and voltage transformer (VT) (not shown), the precision and the linearity of signal have been guaranteed, especially be apparent that under the situation of little current signal, guaranteed the measuring accuracy in the gamut scope equally.Between the current input terminal of current transformer and signal sampling module 2, also be provided with connection terminal (not shown), make things convenient for the maintenance and the replacing of instrument for measuring and recording.
When ground current is monitored, to the residual voltage of central point earthed system, also monitor, so that in case when the unusual or fault of ground connection takes place, can be by to electric current, the analysis-by-synthesis of voltage draws the correct judgement to failure exception.
Total system runs up under the coordination of clock sync signal, and current signal is sampled with the speed of 4000 point/seconds incessantly, has guaranteed the seizure to abnormal signal, and the signal of sampling is enough to the squiggle that structure is drawn electric current.But for the also conserve storage that saves time, only the maximal value of alternating current is carried out correction calculation and storage in the present embodiment, storage data institute can the structure picture be the envelope of abnormal current, these data can be made analysis and the judgement to abnormal current fully.For the control system cost, also in order to improve the reliability of system, so the survey recording system in the present embodiment has adopted single central processing unit mode.This instrument for measuring and recording need not any potentiometer or adjustable element, has avoided changing the error that causes because of the numerical value of adjustable element, and the calibration of instrument and setting work are all finished by surveying recording system.
Above embodiment is only for the usefulness that the present invention is described, but not limiting the scope of the invention.Relevant those skilled in the art under the situation that does not break away from the spirit and scope of the present invention, can also make various conversion or modification, and the technical scheme that all are equal to also should belong within the category of the present invention's protection, is limited by each claim.
Claims (10)
1. neutral resistance instrument for measuring and recording mutation current, comprise that one is provided with the housing of guidance panel and some connection terminals, and be positioned at the mutual inductor that housing links to each other with corresponding wiring terminal, it is characterized in that: also be provided with one in the described housing and survey recording system, this survey recording system comprises a central processing unit, and the load module that links to each other with this central processing unit respectively, output module, data-carrier store, signal sampling module, communication module and clock and dead electricity memory module, wherein:
Described signal sampling module receives from the voltage of mutual inductor or current output signal as its input signal, then this signal is exported to central processing unit after treatment;
Described load module receives from the input signal on the guidance panel, exports it to central processing unit then;
Described output module receives from central processing unit output signal after treatment, and with its demonstration and warning.
2. a kind of neutral resistance instrument for measuring and recording mutation current according to claim 1, it is characterized in that: described signal sampling module comprises a signal condition filtering submodule and the A/D conversion submodule that links to each other with this submodule, this signal condition filtering submodule is receiving inputted signal at first, exports central processing unit through nursing one's health filtered signal to by A/D conversion submodule.
3. a kind of neutral resistance instrument for measuring and recording mutation current according to claim 1, it is characterized in that: described output module comprises output alarm submodule and the display sub-module that an output power is amplified submodule and is attached thereto, and output power is amplified submodule will export to output alarm submodule and display sub-module after the signal amplification after treatment from central processing unit.
4. a kind of neutral resistance instrument for measuring and recording mutation current according to claim 1, it is characterized in that: described communication module comprises that a communication switches chooser module and some communication mode submodules that is attached thereto, communication switch the different communication mode submodule of the changeable selection of chooser module so that system works under different communication modes.
5. a kind of neutral resistance instrument for measuring and recording mutation current according to claim 4 is characterized in that: described communication mode submodule comprises RS485 communication mode submodule and/or RS232 communication mode submodule and/or GSM communication mode submodule and/or infrared communication pattern submodule.
6. a kind of neutral resistance instrument for measuring and recording mutation current according to claim 1 is characterized in that: described load module adopts the mode of keyboard input.
7. a kind of neutral resistance instrument for measuring and recording mutation current according to claim 1 is characterized in that: described mutual inductor is current transformer and voltage transformer (VT).
8. a kind of neutral resistance instrument for measuring and recording mutation current according to claim 7 is characterized in that: also be provided with the connection terminal between the current input terminal of described current transformer and signal sampling module.
9. a kind of neutral resistance instrument for measuring and recording mutation current according to claim 1 is characterized in that: described mutual inductor adopts the amorphous alloy material coiling to form.
10. a kind of neutral resistance instrument for measuring and recording mutation current according to claim 1 is characterized in that: described data-carrier store adopts Serial E
2Prom memory.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007100377084A CN101256205A (en) | 2007-02-27 | 2007-02-27 | Instrument for measuring and recording mutation current of neutral point earthing resistor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007100377084A CN101256205A (en) | 2007-02-27 | 2007-02-27 | Instrument for measuring and recording mutation current of neutral point earthing resistor |
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| CN101256205A true CN101256205A (en) | 2008-09-03 |
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| Application Number | Title | Priority Date | Filing Date |
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| CNA2007100377084A Pending CN101256205A (en) | 2007-02-27 | 2007-02-27 | Instrument for measuring and recording mutation current of neutral point earthing resistor |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103823152A (en) * | 2014-03-11 | 2014-05-28 | 国家电网公司 | Direct-current grounding detection device |
| CN104198877A (en) * | 2014-09-26 | 2014-12-10 | 国家电网公司 | Portable multipoint grounding detector |
| CN104635108A (en) * | 2014-12-24 | 2015-05-20 | 国家电网公司 | Current abrupt change display method and device |
-
2007
- 2007-02-27 CN CNA2007100377084A patent/CN101256205A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103823152A (en) * | 2014-03-11 | 2014-05-28 | 国家电网公司 | Direct-current grounding detection device |
| CN104198877A (en) * | 2014-09-26 | 2014-12-10 | 国家电网公司 | Portable multipoint grounding detector |
| CN104635108A (en) * | 2014-12-24 | 2015-05-20 | 国家电网公司 | Current abrupt change display method and device |
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Application publication date: 20080903 |