CN101046499A - Method of detecting triphase asymmetry failure in low voltage line and comprehensive protection module - Google Patents
Method of detecting triphase asymmetry failure in low voltage line and comprehensive protection module Download PDFInfo
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- CN101046499A CN101046499A CN 200710013315 CN200710013315A CN101046499A CN 101046499 A CN101046499 A CN 101046499A CN 200710013315 CN200710013315 CN 200710013315 CN 200710013315 A CN200710013315 A CN 200710013315A CN 101046499 A CN101046499 A CN 101046499A
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Abstract
The method of detecting triphase asymmetry failure in low voltage line includes zero sequence current time sequence identification and interphase time sequence identification. The comprehensive protection module for triphase asymmetry failure in low voltage line includes one zero sequence voltage signal processing circuit, one zero sequence current signal processing circuit, one asymmetry failure time sequence discriminator, one triphase voltage signal processing circuit and one triphase current signal processing circuit. The present invention can search failed line in 380 V and 660 V power network in high sensitivity and high accuracy, and realize the detection on and protection against phase failure and interphase short circuit.
Description
Technical field
The invention belongs to Power System Faults Detection and protective relaying device, be specifically related to the discriminating and the protection of three kinds of unbalanced faults such as electric leakage of low-voltage circuit single-phase earthing or short circuit, single-phase wire break (phase-deficient operation) and line to line fault.
Background technology
The neutral point of industrial and mining enterprises' low pressure (380V or 660V) electrical network has direct ground connection and earth-free dual mode.For example the colliery underground low-tension network all adopts the isolated neutral mode, and the ground low voltage electric network of general industrial and mining enterprises and rural power grids adopts the three-phase four-wire system mode of neutral-point solid ground more.This three-phase four-wire low-voltage electrical network will be undertaken the three-phase living load power supply of many low pressure asynchronous motors on the one hand, undertakes a large amount of single-phase load electricity consumptions such as office automation equipment, household electrical appliance and illumination simultaneously again.Because single-phase load is difficult to accomplish balanced configuration of three-phase and coordinated operation, causes many circuits of this class low voltage electric network serious three-phase current unbalance often to occur, and cause the bus imbalance of three-phase voltage.Thereby force the single-line to ground fault protection of low-voltage circuit or zero-sequence current protection to have to improve action setting valve (increasing threshold), reduce action sensitivity.The result is that (for example low-voltage overhead line one breaks mutually and drops on the rock when single-phase high resistance ground takes place circuit; on the branch or on the drying ground); because single-phase leakage current over the ground is less; do not reach the action setting valve of low-voltage circuit short-circuit protection or zero-sequence current protection and be failure to actuate for a long time; the result causes that the molten mutually part of power transformer medium voltage side fuse one blows; cause the power transformer phase-deficient operation; this again transformer mostly is the Y/Y0 wiring; thereby cause whole low voltage electric network phase-deficient operation; cause a large amount of asynchronous motors to burn simultaneously; this not only causes device damage and direct economic loss, and causes that relevant electricity consumer production link pauses and other adverse consequencess.Another consequence that singlephase earth fault is not got rid of for a long time is to cause two phase ground short circuit or alternate direct short-circuit.
The applicant has applied for patent of invention " small current grounding system single-phase grounding selecting method and apparatus " (publication number CN1453916A) according to " zero-sequence current (first-harmonic) time sequence logical discrimination then " of oneself invention in April, 2002; Apply for again utility model patent " small current grounding system single-phase grounding selecting device (patent No. ZL02237567.8) " June in the same year, applied for simultaneously again two utility model patents " single-phase earthing wire selector of resonance earthing system (patent No. ZL200520080013.0) " and " time sequence discrimination selective leakage protection unit for low-voltage power network of mines (patent No. ZL200520081430.7) " in January, 2005. The selection method of above-mentioned patent achievement all is to adopt " zero-sequence current sequential discrimination method ", and this line selection apparatus or protector all are made up of single-phase earthing sequential identification module and peripheral circuit.But these selection methods and device only are used for isolated neutral or the neutral point mesolow electrical network through arc suppression coil ( or zero-sequence reactor ) ground connection; Only detect and selective protection, can not be used as the detection and the protection of open phase fault, two-phase short-circuit fault as the single-phase earthing leak current fault.
Summary of the invention
Purpose of the present invention, the one, on " zero-sequence current (first-harmonic) time sequence logical discrimination is then " basis, invent a kind of " any two phasor sequential discrimination methods " in order to solve the detection problem of open phase fault, two-phase short-circuit fault; The 2nd, according to " any two phasor time sequence logical discriminations "; on " mine low-voltage electricity grid sequential discriminating leakage selecting protector " basis, improve; invent a kind of " low-voltage circuit three-phase unbalanced fault comprehensive protection module ", be used for the identification and the protection of single-phase earthing, the phase failure, three kinds of unbalanced faults of line to line fault.
Unbalanced fault detection method of the present invention is: it comprises " zero-sequence current time sequence logical discrimination ", and its feature also comprises " the sequential discrimination methods of any two phasors ", and the step of this method is:
1, the high and low level that a sine wave signal shaping is drawn respectively accounts for 180 ° regular rectangular shape ripple and is defined as benchmark phasor JZ; Rule or non-regular rectangular shape ripple that the sine wave or the non-sinusoidal wave signal shaping of another and JZ same frequency is obtained are defined as ginseng phase demodulation amount CJ, and set the following rule of differentiating:
The rising edge of CJ must lag behind the rising edge of JZ and be ahead of the JZ negative edge, and must lag behind 0 °～180 ° of JZ negative edges of the negative edge of CJ if meet this rule, determine that then phasor CJ must lag behind phasor JZ; Otherwise this rule is invalid.
Differentiate rule design " any two phasor sequential Discr.s " according to this, this sequential Discr. can be a single-chip microcomputer that is provided with two phasor sequential evaluators, or a complex programmable logic device (CPLD) that is provided with " two phasor sequential discriminator circuits ".The sequential discriminator circuit that can comprise a plurality of different functions in sequential Discr..
2, the threephase current transformer TA Secondary Winding from the power network line is taken out three-phase current signal I
a, I
b, I
c, after the I/V conversion, be divided into three groups again through filtering respectively, one group obtains square wave I through shaping respectively
a, I
b, I
cSecond group obtains square wave I through phase shift, shaping respectively
Ay, I
By, I
CyThe 3rd group obtains square wave I through amplitude discrimination, shaping respectively
AF, I
BF, I
CF
Take out three-phase voltage U from voltage transformer (VT) TV Secondary Winding
Ab, U
Bc, U
CaSignal obtains square wave U through phase shift, shaping respectively
Aby, U
Bcy, U
Cay
3,, determine the method for attachment of " two phasor sequential discriminator circuits " input end JZ, CJ according to the line fault feature.In the time will detecting a certain phase in the three-phase line (as the A phase) broken string (phase-deficient operation), then set I
CyBe JZ, I
bBe CJ.In the time will detecting three-phase line certain line to line fault (as the ab line to line fault) fault takes place, then set I
ByBe JZ, I
aBe CJ.
For realizing said method, the present invention has also invented a kind of comprehensive protection module, and this module comprises: residual voltage signal processing circuit and zero sequence current signal I
0Treatment circuit is characterized in that also comprising unbalanced fault sequential Discr., three-phase voltage signal treatment circuit and three-phase current signal treatment circuit, wherein:
Unbalanced fault sequential Discr. can be a single-chip microcomputer that is provided with zero-sequence current sequential evaluator and two phasor sequential evaluators, also can be a complex programmable logic device (CPLD) that is provided with zero-sequence current sequential discriminator circuit and two phasor sequential discriminator circuits.
The three-phase current signal treatment circuit is that the threephase current transformer TA Secondary Winding from the circuit is taken out three-phase current signal I
a, I
b, I
c, be divided into three groups again through after the filtering respectively, one group of I that after shaping, photoelectricity are isolated, inserts " unbalanced fault sequential Discr. " more respectively
a, I
b, I
cThree input ends; Second group of I that after phase shift, shaping, photoelectricity are isolated, inserts " unbalanced fault sequential Discr. " respectively again
Ay, I
By, I
CyThree input ends; The 3rd group respectively again through amplitude discrimination, shaping, the light I every back access " unbalanced fault sequential Discr. "
AF, I
BF, I
CFThree input ends.
The three-phase voltage signal treatment circuit is to take out three-phase voltage signal U from voltage transformer (VT) TV Secondary Winding
Ab, U
Bc, U
CaAfter isolating, filtering, phase shift, shaping, photoelectricity receives the corresponding input end U of " unbalanced fault sequential Discr. " respectively
Aby, U
Bcy, U
Cay
Good effect of the present invention is:
1, will be based on zero sequence first-harmonic time sequence logical discrimination single-phase grounding selecting method and protective device then; from only being used for the not direct earthing electric network of neutral point; promote the use of the three-phase four-wire system electrical network of neutral-point solid ground; solved the single-phase sensitivity and high accuracy problem of 380V, 660V electrical network of neutral ground, had new practical value and promotion prospect through the high resistance grounding failure line selection.
2, on the basis of zero-sequence current (first-harmonic) sequential discrimination method; electric current in the three-phase system, voltage " the sequential discrimination methods of two phasors " have arbitrarily been invented; further realized the detection and the protection of unbalanced faults such as phase-deficient operation, line to line fault, range of application is broader.
3, " unbalanced fault comprehensive protection module " is though from the directly grounded three-phase four-wire low-voltage electrical network of neutral point actual conditions project verification research and development; but can be used for not directly grounded low voltage electric network of neutral point and even medium voltage network equally, have versatility at the mesolow electrical network.
4, single-phase earthing in the power circuit, open-phase running, three kinds of unbalanced fault probability of happening of line to line fault and, more than 95% of all fault general probabilitys on the line is busy the road; " unbalanced fault comprehensive protection module " makes that the fault detect more than 95% is only differentiated according to sequential logic with protection in the three-phase line; and do not need concrete calculation of parameter and adjust; thereby the detection of line fault and protection are greatly simplified, and operation maintenance is easier.
Description of drawings
Fig. 1 is " time sequence logical discrimination between any two phasors then " synoptic diagram in the inventive method;
Fig. 2 is the ultimate principle figure of " two phasor sequential discriminator circuits " in " unbalanced fault sequential Discr. ";
Fig. 3 is " unbalanced fault comprehensive protection module " principle of compositionality block scheme.
Embodiment
The time sequence logical discrimination setting situation then of any two phasors in the inventive method now is described in conjunction with Fig. 1, and the waveform sequential relationship of JZ shown in a, the b and CJ meets this rule among the figure, and the waveform sequential relationship of JZ shown in c, d, the e and CJ does not meet this rule.
The ultimate principle of two phasor sequential discriminator circuits now is described in conjunction with Fig. 2, and it is by two d type flip flop DC1, DC2, two not gate F1, F2, and one two Sheffer stroke gate YF, R-S latch RS and frequency division and delay switching circuit are formed.In Fig. 2, phasor JZ connects the D input end of DC1, connects the D input end of DC2 after the JZ negate; Phasor CJ connects the input end of clock of DC1, connects the input end of clock of DC2 after the CJ negate; After handling through frequency division, delay switching circuit, the JZ signal connects the R input end of DC1 and DC2; The output terminal Q of DC1 and DC2 connects two input ends of YF, the S end of the output termination RS of YF, and the R termination reset signal of RS, the output terminal of RS is exactly the sequential identification result, if high level shows that phasor CJ lags behind phasor JZ.
The circuit structure of an embodiment of comprehensive protection module of the present invention now is described with Fig. 3.Present embodiment is mainly used to guard low-voltage circuit three-phase unbalanced fault, and core devices is sequential Discr. VC1.
In the low-voltage circuit shown in the accompanying drawing 3 " three-phase unbalanced fault comprehensive protection module "; constitute the sequential Discr. by a slice programmable asic VC1 (ASIC), the sequential Discr. comprises the sequential discriminator circuit (the detailed circuit principle as shown in Figure 2) of a plurality of different functions.The input end of VC1 inserts three-phase voltage U respectively from CZ1
Ab, U
Bc, U
CaSignal wire, U
Ab, U
Bc, U
CaSignal wire respectively through filtering circuit, phase-shift circuit, shaping circuit, light every coupled circuit, electrically connect back output U
Aby, U
Bcy, U
CayInsert 28,29, No. 30 pins of sequential Discr. VC1 respectively; The input end of VC1 inserts bus U from CZ1
oSignal wire, U
oThe filtering circuit that signal line passes is total is divided into two branch roads then: first branch road passes through phase-shift circuit, amplitude discrimination and shaping circuit, light successively every coupled circuit, electrically connects back output U
OFSignal inserts No. 32 pins of sequential Discr. VC1; Second branch road is divided into two branch roads again behind total phase-shift circuit: first branch road passes through shaping circuit, light successively every coupled circuit, electrically connects back output U
OJ+Signal inserts No. 33 pins of sequential Discr. VC1, and second branch road passes through negate circuit, shaping circuit, light successively every coupled circuit, electrically connects back output U
OJ-Signal inserts No. 34 pins of sequential Discr. VC1; The input end of VC1 also inserts zero-sequence current I from socket CZ1
oSignal wire, I
oSignal wire every circuit, electrically connects No. 31 pins that sequential Discr. VC1 is inserted in the back through filtering circuit, phase-shift circuit, amplitude discrimination circuit, shaping circuit, light; The input end of VC1 also inserts three-phase current I from socket CZ1
a, I
b, I
cSignal wire, this I
a, I
b, I
cSignal wire is divided into four groups of branch roads respectively behind total filtering circuit: first group of branch road successively through phase-shift circuit, shaping circuit, light every circuit, electrically connect back output I
AF, I
BF, I
CF, insert 49,48, No. 47 pins of sequential Discr. VC1 respectively; Second group of branch road successively through shaping circuit, light every circuit, electrically connect back output I
a, I
b, I
c, insert 52,51, No. 50 pins of sequential Discr. VC1 respectively; The 3rd group of branch road successively through amplitude discrimination circuit, shaping circuit, light every circuit, electrically connect back output I
AF, I
BF, I
CF, insert 46,45, No. 38 pins of sequential Discr. VC1 respectively; The 4th group of branch road successively through than width of cloth circuit, shaping circuit, light every circuit, electrically connect back output I
Ag, I
Cg, insert 26, No. 27 pins of sequential Discr. VC1 respectively.58,59,60,68,69, No. 70 pins of the output pin of VC1 meet accessory power outlet CZ3 through No. 71 pins that driving circuit meets each pin of accessory power outlet CZ2 VC1 respectively through light behind circuit, driving circuit; 54,55,56,57, No. 80 pins of VC1 connect the corresponding pin of accessory power outlet CZ4 respectively behind photoelectric isolating circuit.
Claims (3)
1, a kind of low-voltage circuit three-phase unbalanced fault detection method, it comprises the zero-sequence current time sequence logical discrimination, and its feature also comprises any two phasor sequential discrimination methods, and the concrete steps of this method are:
(1) the high and low level that a sine wave signal shaping is drawn respectively accounts for 180 ° regular rectangular shape ripple and is defined as benchmark phasor JZ; Rule or non-regular rectangular shape ripple that the sine wave or the non-sinusoidal wave signal shaping of another and JZ same frequency is obtained are defined as ginseng phase demodulation amount CJ, and set the following rule of differentiating:
The rising edge of CJ must lag behind the rising edge of JZ and be ahead of the JZ negative edge, and must lag behind 0 °～180 ° of JZ negative edges of the negative edge of CJ if meet this rule, determine that then phasor CJ must lag behind phasor JZ; Otherwise this rule is invalid;
Design any two phasor sequential Discr.s according to this discriminating rule;
(2) the threephase current transformer TA Secondary Winding from the power network line is taken out three-phase current signal I
a, I
b, I
c, after the I/V conversion, be divided into three groups again through filtering respectively, one group obtains square wave I through shaping respectively
a, I
b, Ic; Second group obtains square wave I through phase shift, shaping respectively
Ay, I
By, I
CyThe 3rd group obtains square wave I through amplitude discrimination, shaping respectively
AF, I
BF, I
CF
Take out three-phase voltage U from voltage transformer (VT) TV Secondary Winding
Ab, U
Bc, U
CaSignal obtains square wave U through phase shift, shaping respectively
Aby, U
Bcy, U
Cay
(3), determine the method for attachment of " two phasor sequential discriminator circuits " input end JZ, CJ according to the line fault feature.A certain when breaking mutually when detecting in the three-phase line, then set I
CyBe JZ, I
bBe CJ.In the time will detecting three-phase line certain two-phase short-circuit fault takes place, then set I
ByBe JZ, I
aBe CJ.
2, a kind of low-voltage circuit three-phase unbalanced fault comprehensive protection module; it comprises residual voltage signal processing circuit and zero sequence current signal treatment circuit; it is characterized in that also comprising unbalanced fault sequential Discr., three-phase voltage signal treatment circuit and three-phase current signal treatment circuit, wherein:
Described unbalanced fault sequential Discr. is a single-chip microcomputer that is provided with zero-sequence current sequential evaluator and two phasor sequential evaluators;
Described three-phase current signal treatment circuit is that the threephase current transformer TA Secondary Winding from the circuit is taken out three-phase current signal I
a, I
b, I
c, be divided into three groups again through after the filtering respectively, one group of I that after shaping, photoelectricity are isolated, inserts " unbalanced fault sequential Discr. " more respectively
a, I
b, I
cThree input ends; Second group of I that after phase shift, shaping, photoelectricity are isolated, inserts unbalanced fault sequential Discr. respectively again
Ay, I
By, I
CyThree input ends; The 3rd group respectively again through amplitude discrimination, shaping, the light I every back access " unbalanced fault sequential Discr. "
AF, I
BF, I
CFThree input ends;
Described three-phase voltage signal treatment circuit is to take out three-phase voltage signal U from voltage transformer (VT) TV Secondary Winding
Ab, U
Bc, U
CaAfter isolating, filtering, phase shift, shaping, photoelectricity receives the corresponding input end U of unbalanced fault sequential Discr. respectively
Aby, U
Bcy, U
Cay
3, low-voltage circuit three-phase unbalanced fault comprehensive protection module as claimed in claim 1; it is characterized in that described unbalanced fault sequential Discr. is a complex programmable logic device (CPLD) that is provided with zero-sequence current sequential discriminator circuit and two phasor sequential discriminator circuits.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB200710013315XA CN100552465C (en) | 2007-02-13 | 2007-02-13 | Three-phase asymmetric fault detection method and integrated protection module of low-voltage line |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB200710013315XA CN100552465C (en) | 2007-02-13 | 2007-02-13 | Three-phase asymmetric fault detection method and integrated protection module of low-voltage line |
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| Publication Number | Publication Date |
|---|---|
| CN101046499A true CN101046499A (en) | 2007-10-03 |
| CN100552465C CN100552465C (en) | 2009-10-21 |
Family
ID=38771263
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB200710013315XA Expired - Fee Related CN100552465C (en) | 2007-02-13 | 2007-02-13 | Three-phase asymmetric fault detection method and integrated protection module of low-voltage line |
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| CN (1) | CN100552465C (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102185295A (en) * | 2011-04-27 | 2011-09-14 | 江苏大学 | Selective short-circuited protection device and method for mine low-voltage power supply system |
| CN103261900A (en) * | 2010-11-05 | 2013-08-21 | 西门子公司 | Monitoring a power supply line supplied at one end for earth faults |
| WO2016008143A1 (en) * | 2014-07-17 | 2016-01-21 | Siemens Aktiengesellschaft | Broken conductor detection method and apparatus |
| CN105929257A (en) * | 2016-05-30 | 2016-09-07 | 重庆大学 | Fast three-phase rectification missing phase detection and normal phase tracking method |
| CN108108584A (en) * | 2017-11-14 | 2018-06-01 | 广东电网有限责任公司电力调度控制中心 | The short-circuit parameter acquisition methods and system of a kind of Three-phase Power Systems asymmetry equipment |
| CN109342944A (en) * | 2018-11-21 | 2019-02-15 | 深圳和而泰智能控制股份有限公司 | A kind of electric machines test method and apparatus |
| CN110098596A (en) * | 2017-12-28 | 2019-08-06 | 许继集团有限公司 | A kind of identification of reactor current transformer disconnection, differential protecting method and device |
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2007
- 2007-02-13 CN CNB200710013315XA patent/CN100552465C/en not_active Expired - Fee Related
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103261900A (en) * | 2010-11-05 | 2013-08-21 | 西门子公司 | Monitoring a power supply line supplied at one end for earth faults |
| CN103261900B (en) * | 2010-11-05 | 2015-08-05 | 西门子公司 | The method that the ground short circuit of the supply lines of the one-sided power supply of three phase supply net is monitored and electrical protection apparatus |
| CN102185295A (en) * | 2011-04-27 | 2011-09-14 | 江苏大学 | Selective short-circuited protection device and method for mine low-voltage power supply system |
| CN102185295B (en) * | 2011-04-27 | 2014-08-20 | 江苏大学 | Selective short-circuited protection device and method for mine low-voltage power supply system |
| US10365313B2 (en) | 2014-07-17 | 2019-07-30 | Siemens Aktiengesellschaft | Broken conductor detection method and apparatus |
| WO2016008143A1 (en) * | 2014-07-17 | 2016-01-21 | Siemens Aktiengesellschaft | Broken conductor detection method and apparatus |
| CN105929257A (en) * | 2016-05-30 | 2016-09-07 | 重庆大学 | Fast three-phase rectification missing phase detection and normal phase tracking method |
| CN105929257B (en) * | 2016-05-30 | 2018-09-21 | 重庆大学 | A kind of quick three phase rectifier pile defection and normal phase-tracking method |
| CN108108584A (en) * | 2017-11-14 | 2018-06-01 | 广东电网有限责任公司电力调度控制中心 | The short-circuit parameter acquisition methods and system of a kind of Three-phase Power Systems asymmetry equipment |
| CN108108584B (en) * | 2017-11-14 | 2022-05-03 | 广东电网有限责任公司电力调度控制中心 | Short-circuit parameter acquisition method and system for three-phase asymmetric equipment of power system |
| CN110098596A (en) * | 2017-12-28 | 2019-08-06 | 许继集团有限公司 | A kind of identification of reactor current transformer disconnection, differential protecting method and device |
| CN110098596B (en) * | 2017-12-28 | 2021-08-03 | 许继集团有限公司 | A kind of reactor current transformer disconnection identification, differential protection method and device |
| CN109342944A (en) * | 2018-11-21 | 2019-02-15 | 深圳和而泰智能控制股份有限公司 | A kind of electric machines test method and apparatus |
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