CN103869194A - New method for judging and measuring electrical power system resonance - Google Patents
New method for judging and measuring electrical power system resonance Download PDFInfo
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- CN103869194A CN103869194A CN201410110340.XA CN201410110340A CN103869194A CN 103869194 A CN103869194 A CN 103869194A CN 201410110340 A CN201410110340 A CN 201410110340A CN 103869194 A CN103869194 A CN 103869194A
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Abstract
The invention discloses a new method for judging and measuring electrical power system resonance. According to the electrical power system, a current sensor is additionally arranged between a primary neutral point of a complete insulating voltage transformer and the ground, a zero-sequence current flowing through the primary neutral point of the voltage transformer is received, a current signal of the current sensor is connected to a microcomputer detecting device through a secondary cable, the current in the current sensor is detected and analyzed, and accordingly the occurrence of resonance and the characteristic of the occurrence resonance are judged. The new method for judging and measuring the electrical power system resonance is provided for solving the problem that the resonance in the electrical power system in China at present is judged not in time and inaccurately. The new method provides a reliable basis for alarming and eliminating of resonance failures.
Description
Technical field
The present invention relates to judgement and the measuring technique of electric system resonance, one is arranged between neutral point of voltage transformer (VT) and ground specifically, the measurement of the zero-sequence current by a neutral point of convection current superpotential mutual inductor, the situation of judgement system generation resonance, for the control of resonance provides the method for basis for estimation accurately.
background technology
The intermediate voltage electric power system of China adopts neutral non-effective grounding mode mostly, this system has higher power supply reliability, but superpotential is relatively serious, particularly because of the nonlinear resonance of the saturated generation of voltage transformer (VT), common especially, not only amplitude is higher for it, and energy is very large, and can spread all over whole electrical network, destructiveness is very large, once superpotential occurs, often cause damage and the large-area power outage of electrical equipment.Record and the crash analysis of electrical production operation for many years show, in Medial & Low Voltage Power Network, Overvoltage great majority are all caused by resonance phenomena.
Resonance is in fault and singlephase earth fault, broken string, High-voltage Fuse Blow and Voltage Transformer Damages fault, from phenomenon, resemble in many points, in operational process, if judge unclearly, deal with improperly, processing time can be incured loss through delay, also, easily because judging the processing that makes the mistake by accident, make extremely to become accident, cause device damage.To resonance, judgement is all to determine according to the size of residual voltage at present, although this criterion is simple, cannot distinguish broken string, ground connection, fuse blows and mutual inductor self damage fault but exist, once there is erroneous judgement, not only affect the timely processing of fault, the processing of mistake also can cause larger accident, and consequence is serious.Adopt the criterion of residual voltage as resonance, for avoiding frequent erroneous judgement, need judgment threshold be arranged highlyer, its result causing is in the time that resonance just starts to occur, cannot detect, must wait resonance to develop into certain intensity time, then process, now resonance not only causes certain harm to system, and the resonance intractability of higher-strength is larger.The problems referred to above are urgently to be resolved hurrily.
Summary of the invention
The object of the invention is to exist for resonance judgement in the electric system of current China not in time, inaccurate problem, a kind of method that electric system resonance judgement is provided and measures, for warning and the elimination of resonance fault provide reliable foundation.
For addressing the above problem, technical scheme of the present invention is:
1. a new method for the judgement of electric system resonance and measurement, is characterized in that, the method comprises the following steps:
(1) add a current sensor at a kind of voltage transformer (VT) primary side of all insulation between over the ground, receive the zero-sequence current that flows through a neutral point of voltage transformer (VT);
(2) current signal by secondary cable, current sensor being received is connected to pc detecting instrument;
(3) pc detecting instrument carries out determination and analysis by the electric current in current sensor, thereby judges the generation of resonance and the character of resonance occurs; The job step of pc detecting instrument is: external communication signal access analog quantity converter plate, low-voltage simulation amount signal between analog quantity converter signal is converted to-5V ~+5V, this analog quantity is first carried out low-pass filtering and shaping after entering mainboard, is then converted to digital signal by AD; CPU calculates and analyzes digital signal, calculates current amplitude and power frequency, then goes out the character of resonance according to the size of zero-sequence current and frequency analysis, preserves fault partial data;
(4) calculating and analysis result are exported by liquid crystal display, communication module and three kinds of modes of alarm module.
2. the current sensor described in is zero sequence current mutual inductor or the Hall element of electromagnetic type.
Beneficial effect of the present invention:
The present invention judges resonance fault by detecting neutral point of voltage transformer (VT) current signal over the ground, have simple, reliable, failing to judge can avoid low earthquake intensity resonance time, also can avoid the interference of the faults such as system single-phase earthing, broken string, High-voltage Fuse Blow and Voltage Transformer Damages, be the accurate judgement of resonance fault and the convenient foundation of processing raising in time.
The present invention has principle science, method is simple and reliable, advantage with low cost.
Brief description of the drawings
Fig. 1 is the structural representation of electric system resonance judgement of the present invention and measurement mechanism.
Fig. 2 is pc detecting instrument hardware block diagram.
In figure: 1. current sensor LCK, 2. pc detecting instrument WLJ, 3. voltage transformer pt, 4. communication module, 5. liquid crystal display, 6. warning node, 7. G, 8. embedded main board, 9. analog quantity converter plate, 10. cable, 11. 4U cabinets, 12. CPU, 13. internal memories, 14.Flash storer, 15.AD, 16. back panel connectors, 17. demonstrations, 18. communications, 19. report to the police, 20. communications and alarm module.
Embodiment
Referring to Fig. 1, the invention provides one be arranged on voltage transformer (VT) neutral point over the ground between, detect to judge the method for resonance and resonance character by the zero-sequence current of convection current superpotential mutual inductor neutral point.
Described current sensor LCK1 is arranged between 3 neutral points of voltage transformer pt and ground G7, upper end is connected to 3 neutral points of voltage transformer pt, lower end ground connection, it can adopt electromagnetic current transducer, also can adopt Hall Element Current Sensor, the withstand voltage of this sensor must not be lower than AC5000V.
The job step of pc detecting instrument is:
Referring to Fig. 2, pc detecting instrument WLJ2 is made up of embedded main board 8, analog quantity converter plate 9, communication and alarm module 20, liquid crystal display 5 and power supply, contains communication module 4 and warning node 6 in communication and alarm module 20; All boards are installed in 4U cabinet 11, and mainboard is the core of device, include Flash storer 14, the AD15 employing chip of 12M, the RS485 serial ports of internal memory 13|, the 128M of 32 ARM, the 32M of dominant frequency 500MHz.Mainboard writes application program with compilation or C language.
The current signal of current sensor LCK1 accesses analog quantity converter plate 9A1 and A2 by cable 10, low-voltage simulation amount signal between converter signal is converted to-5V ~+5V, this analog quantity enters that embedded main board 8 is rear first carries out low-pass filtering and shaping, is then converted to digital signal by AD15.CPU12 calculates digital signal, calculate amplitude and the frequency of electric current, go out again the character of resonance according to the size of zero-sequence current amplitude and frequency analysis, preserve fault partial data, finally by calculatings and analysis result by liquid crystal display 5, communication module 4 and warning node 6 show respectively 17, communication 18 and warning 19.
Described mainboard is connected by back panel connector 16 with analog quantity converter plate 9, communication and alarm module 20 and liquid crystal display 5; By secondary cable 10, the current signal of continuous current sensor is connected to the analog quantity converter plate 9 of pc detecting instrument; By secondary cable 10, communication module 4 is connected to upper managing computer
The determination methods of resonance is:
When normal operation, electric current by a neutral point of voltage transformer (VT) is very little, general I0<3mA, in the time that system has resonance fault to occur, I0 will sharply increase, consider that voltage transformer (VT) has certain capability of overload, particularly short-time overload capacity is very large, for the reliability of assurance device, therefore we arrange in the time of I0>25mA, device is judged as resonance and occurs, at this moment I0 is calculated and analyzed, according to the amplitude of I0 and frequency, judge the earthquake intensity of occurred resonance and the character of resonance, but when I0>500mA, for high earthquake intensity resonance, need process immediately, survey numerical value according to real frequency, the fault that can accurately judge generation is high-frequency resonant, industrial frequency resonance or Subharmonic Resonance.Pick-up unit output alarm in the time that fault occurs, reminds staff to process, and records simultaneously and exports and calculate and analysis result, for accident treatment and analysis reference.
Claims (2)
1. a new method for the judgement of electric system resonance and measurement, is characterized in that, the method comprises the following steps:
(1) between neutral point of the voltage transformer (VT) of a kind of all insulation of electric system and ground, add a current sensor, receive the zero-sequence current that flows through a neutral point of voltage transformer (VT);
(2) current signal by secondary cable, current sensor being received is connected to pc detecting instrument;
(3) pc detecting instrument carries out determination and analysis by the electric current in current sensor, thereby judges the generation of resonance and the character of resonance occurs; The job step of pc detecting instrument is: external communication signal access analog quantity converter plate, low-voltage simulation amount signal between analog quantity converter signal is converted to-5V ~+5V, this analog quantity is first carried out low-pass filtering and shaping after entering mainboard, is then converted to digital signal by AD; CPU calculates and analyzes digital signal, calculates current amplitude and power frequency, then goes out the character of resonance according to the size of zero-sequence current and frequency analysis, preserves fault partial data;
(4) calculating and analysis result are exported by liquid crystal display, communication module and three kinds of modes of alarm module.
2. the new method of a kind of electric system resonance judgement according to claim 1 and measurement, is characterized in that the zero sequence current mutual inductor that described current sensor is electromagnetic type or Hall element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410110340.XA CN103869194A (en) | 2014-03-24 | 2014-03-24 | New method for judging and measuring electrical power system resonance |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201410110340.XA CN103869194A (en) | 2014-03-24 | 2014-03-24 | New method for judging and measuring electrical power system resonance |
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| CN103869194A true CN103869194A (en) | 2014-06-18 |
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| CN201410110340.XA Pending CN103869194A (en) | 2014-03-24 | 2014-03-24 | New method for judging and measuring electrical power system resonance |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108169630A (en) * | 2018-03-08 | 2018-06-15 | 云南电网有限责任公司电力科学研究院 | A kind of device and method of neutral point ungrounded electric network resonance on-line monitoring |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62206466A (en) * | 1986-03-07 | 1987-09-10 | Toshiba Corp | Transformer for capacitor type instrument |
| CN200993669Y (en) * | 2005-11-17 | 2007-12-19 | 济南富吉电气有限公司 | Small-current earthing wire-selecting positioning device capable of eliminating PT harmonic vibration |
| CN101588064A (en) * | 2009-07-06 | 2009-11-25 | 曲娜 | Intelligent neutral point harmonic elimination apparatus |
| CN103414155A (en) * | 2013-08-21 | 2013-11-27 | 安徽泰隆电气有限公司 | Neutral point installation electronic type rapid harmonic-vibration eliminating device |
-
2014
- 2014-03-24 CN CN201410110340.XA patent/CN103869194A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62206466A (en) * | 1986-03-07 | 1987-09-10 | Toshiba Corp | Transformer for capacitor type instrument |
| CN200993669Y (en) * | 2005-11-17 | 2007-12-19 | 济南富吉电气有限公司 | Small-current earthing wire-selecting positioning device capable of eliminating PT harmonic vibration |
| CN101588064A (en) * | 2009-07-06 | 2009-11-25 | 曲娜 | Intelligent neutral point harmonic elimination apparatus |
| CN103414155A (en) * | 2013-08-21 | 2013-11-27 | 安徽泰隆电气有限公司 | Neutral point installation electronic type rapid harmonic-vibration eliminating device |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108169630A (en) * | 2018-03-08 | 2018-06-15 | 云南电网有限责任公司电力科学研究院 | A kind of device and method of neutral point ungrounded electric network resonance on-line monitoring |
| CN108169630B (en) * | 2018-03-08 | 2023-10-20 | 云南电网有限责任公司电力科学研究院 | Device and method for on-line monitoring resonance of neutral point ungrounded power grid |
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Application publication date: 20140618 |