CN101340082B - Stator grounding protection method of additional electric source intermittent injection type power generator - Google Patents
Stator grounding protection method of additional electric source intermittent injection type power generator Download PDFInfo
- Publication number
- CN101340082B CN101340082B CN2008101161202A CN200810116120A CN101340082B CN 101340082 B CN101340082 B CN 101340082B CN 2008101161202 A CN2008101161202 A CN 2008101161202A CN 200810116120 A CN200810116120 A CN 200810116120A CN 101340082 B CN101340082 B CN 101340082B
- Authority
- CN
- China
- Prior art keywords
- generator
- distribution transformer
- voltage
- ground fault
- protection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000002347 injection Methods 0.000 title claims abstract description 16
- 239000007924 injection Substances 0.000 title claims abstract description 16
- 238000000034 method Methods 0.000 title claims abstract description 15
- 238000004804 winding Methods 0.000 claims description 11
- 230000007935 neutral effect Effects 0.000 claims description 8
- 238000005070 sampling Methods 0.000 claims description 6
- 238000006243 chemical reaction Methods 0.000 claims description 4
- 101100433727 Caenorhabditis elegans got-1.2 gene Proteins 0.000 claims description 2
- 101100489867 Mus musculus Got2 gene Proteins 0.000 claims description 2
- 238000004364 calculation method Methods 0.000 abstract description 5
- 230000007704 transition Effects 0.000 abstract description 4
- 230000002964 excitative effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 238000010205 computational analysis Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Images
Landscapes
- Control Of Eletrric Generators (AREA)
- Protection Of Generators And Motors (AREA)
Abstract
The invention relates to a ground protection method of a stator of an intermittent injection type generator with additional power supply, belongs to the technical field of the relay protection of the main equipment of a power system and is characterized in that before the injected power supply of 20Hz is injected into the generator, the frequency of the generator is firstly detected; nT data of a plurality of integral periods is saved; then the power supply of 20Hz is injected in the same period; and the injection is carried out alternatively and repeatedly so as to cause the power supply of 20Hz to be injected into the generator intermittently. nT is taken as a calculation interval; the increments of voltage and current that are secondarily measured are respectively calculated; signals of 20Hz are extracted from the increments of the voltage and current to eliminate the influences of signals of a generator body, and the ground transition resistance values of the generator are calculated. The method solves the problem that the stator ground protection with the additional power supply of 20Hz has to be locked in the on and off processes of the generator and enlarges the protection scope.
Description
Technical field
The invention belongs to the power system main equipment technical field of relay protection, relate in particular to a kind of intermittent injection type earthing protection method for stator of power generator of the 20Hz of adding power supply.
Background technology
According to statistics, in the body fault that the above generator of national 100MW in every year takes place, the stator grounding fault accounts for quite great proportion.The tendency that phase fault that the generator stator ground fault is even more serious often or shorted-turn fault take place, reliable and the sensitive action of stator ground fault protection can significantly reduce the occurrence probability of these catastrophe failures.If earth fault current is limited in the safety ground current range, generator stator core can be avoided damage, and the direct and indirect economic loss that is caused by fault also will significantly reduce.For 100MW and above generating set, not only require the stator ground fault protection of installing 100% protection zone, also require at stator winding during arbitrarily a bit through certain transition resistance ground connection, protection can sensitive action, to prevent the further expansion of earth fault.Therefore, stator ground fault protection is the important component part in the generator relaying protection system.
Past; generator mainly disposes zero-sequence fundamental voltage type and third harmonic voltage type stator ground fault protection; but because the former exists the protection dead band and the latter to have the deficiency of poor reliability; by contrast; the used signal of injected type stator ground protection adds; have the reliability height, highly sensitive and with characteristics such as abort situation is irrelevant; newly-built and with the protection of the high-rating generator built in generally adopted, inject wherein that 20Hz power supply formula stator ground fault protection is simple because of criterion, debugging convenient use more extensive.
At present newly-built and the high-rating generator of building adopted the neutral grounding mode of distribution transformer secondary side connecting resistance, the protection of installing additional power source type stator ground fault increases gradually.But inject the protection of 20Hz power-type generator stator ground at present; the influence that changed by generator frequency; in the start and stop process (particularly at pumped storage unit, gas turbine unit) of generator, can not realize whole process protection, during 10～40Hz, want latch-up protection.The another kind of stator ground fault protection that injects the 12.5Hz signal also only can be at generator realization defencive function during static and specified operation.
In order to improve protection sensitivity; eliminate the operation dead band; ensure the safe and stable operation of generator; the present invention proposes a kind of stator grounding protection method of additional electric source intermittent injection type power generator; eliminate the influence of generator signal that body produces, realize adding the full operating mode running protection of 20Hz power supply stator ground fault protection generator.
Summary of the invention
The object of the present invention is to provide a kind of stator grounding protection method of additional electric source intermittent injection type power generator.
Stator grounding protection method of additional electric source intermittent injection type power generator is characterized in that containing successively following steps:
Step (1) initialization:
Detect the running frequency of generator, and the time nT that uses when setting the voltage u that gathers the distribution transformer secondary side and current i according to detected running frequency, wherein, T is the cycle of operation of generator, n is a periodicity, determines in the following manner:
When the running frequency of generator was lower than 20Hz, n got 1～2,
When the running frequency of generator was higher than 20Hz, n got 2～5,
So that make the complete cycle that had both comprised several generator operation frequencies in the image data, comprise the complete cycle of at least one 20Hz again;
Step (2) is injected described generator neutral point to the 20Hz power supply via described distribution transformer secondary side winding;
Step (3) is gathered the voltage u of this distribution transformer secondary side with a voltage divider that is attempted by on the described distribution transformer secondary side winding, the current i of gathering this distribution transformer secondary side again with a current transformer that is serially connected on the described distribution transformer secondary side winding, sampling time is nT, sampled data the intermittence of a described collection inject that the stator ground fault protection device switches through low pass filter, variable connector successively and analog-to-digital conversion after, be input among the CPU and preserve;
After time, the 20Hz power supply signal in described generator injects identical sampling time nT is preserved the voltage u of the distribution transformer secondary side that measures and the value of current i to step (4) simultaneously through nT;
Step (5) repeating step (3) and step (4) realize that the 20Hz power supply intermittently injects described generator;
Step (6) is the counting period with sampling time nT, calculates the increment Delta u and the Δ i of described voltage u and current i sampled data respectively:
Δu＝u(t)-u(t-nT)，Δi＝i(t)-i(t-nT)；
Step (7) the calculating 20Hz voltage u and the increment Delta u of current i sampled data, the component among the Δ i
The stator winding that step (8) is calculated as follows described distribution transformer secondary side is admittance Y over the ground:
Step (9) is calculated as follows the ground fault resistance R that converts primary side
g:
The described CPU of step (10) according to set and the protection of storage comes respectively with high setting value of ground fault resistance and the low setting value of earth resistance and step (9) in the ground fault resistance R that obtains
gCompare:
As described ground fault resistance R
gWhen being lower than the high setting value of ground fault resistance that protection sets, send alarm signal;
As described ground fault resistance R
gBe lower than when protecting the earth resistance of setting to hang down setting value, send trip signal.
Computational analysis proves: the invention solves the existing 20Hz power supply stator ground fault protection that adds; in generator start and stop process, need locking to avoid malfunction; the problem that can not omnidistance put into operation; result of calculation is not subjected to the influence of generator body signal; eliminate protection operation dead band, enlarged protection range.
Description of drawings
Fig. 1 is the master section wiring schematic diagram of the embodiment of the invention.
Fig. 2 is the intermittent injection type stator ground fault protection device operation principle block diagram of the embodiment of the invention.
Fig. 3 is a T type equivalent electric circuit of considering the 20Hz intermittent injection type stator ground fault protection of distribution transformer parameter.
Fig. 4 is the flow chart of embodiment of the invention discontinuous injected type stator ground protection.
Fig. 5 is that generator starts when operating in 40Hz in the embodiment of the invention, and generator is through transition resistance generation earth fault, the grounding resistance of intermittent injection type stator ground fault protection, and wherein figure (a) be Δ u (t) curve, and figure (b) is Δ i (t) curve, and scheming (c) is R
g(t) curve.
Embodiment
Below in conjunction with accompanying drawing principle of the present invention and concrete execution mode are described once.
Device and existing microcomputer protective relay device that the present invention adopts are similar, are existing technology, as depicted in figs. 1 and 2.G represents generator among Fig. 1, and T represents main transformer, T
nExpression generator neutral point distribution transformer, R
nBe neutral point secondary side earth resistance, VD is the secondary side voltage divider, and CT is the intermediate current instrument transformer.In the present embodiment for add the 20Hz power supply intermittently injection device be to inject generator through the 20Hz band pass filter by generator neutral point distribution transformer secondary side, measure the voltage u and the current i of secondary side by voltage divider and intermediate current instrument transformer.
Fig. 2 is the specific implementation of embodiment discontinuous injected type stator ground protection device; voltage u and current i; through AC converter (V/V; I/V) these secondary voltages are become the small voltage signal with current conversion; through low pass filter filtering; CPLD complex programmable sequence controller control variable connector switches each road input variable and 16 A/D converters carry out the conversion of analog quantity and digital quantity; each digital quantity is input among the CPU (DSP TMS320C32) and finishes stator ground fault protection and exported by CPLD complex programmable sequence controller control switch amount according to result of calculation; post a letter or trip by the corresponding relays execution, provide fault message simultaneously.Wherein EEPROM is used for stored program and protection definite value, and SRAM and FLASH are used for intermediate variable that storage protection calculates and fault message etc.
When analyzing the equivalent electric circuit of additional power source type one-phase ground protection in the past, very I is ignoring to think the leakage impedance of distribution transformer, and excitatory impedance is very big thinks open circuit.In fact, the excitatory impedance of distribution transformer is not an infinity, and leakage reactance also can produce pressure drop, is the T type equivalent electric circuit of considering the distribution transformer parameter as Fig. 3.Wherein: R '
1, L '
1With R
2, L
2Be respectively the ohmic leakage and the leakage inductance of first and second side winding; R '
m, L '
mBe excitatory resistance and magnetizing inductance; Each parameter is the value of converting secondary side under the 20Hz, wherein R '
1=R
2=R
k/ 2, L '
1=L
2=L
k/ 2; R
k, L
kBe the ohmic leakage and the leakage inductance of distribution transformer.The parameter of distribution transformer can be recorded by unloaded and short circuit experiment.R
20Be the internal resistance that 20Hz injects power supply, u
20Be that 20Hz injects power supply, R '
gBe the generator earth fault transition resistance of converting the distribution transformer secondary side, u '
gBe the residual voltage that is produced by the body signal after the generator generation earth fault, the frequency of this voltage is the running frequency of generator.
When not considering the parameter influence of neutral ground device distribution transformer, the increment Delta u of the 20Hz voltage and current that is approximately primary side by the increment Delta u and the Δ i of secondary side 20Hz voltage and current
sWith Δ i
s, can calculate primary side ground fault resistance value by Δ u and Δ i.
When considering the parameter influence of neutral ground device distribution transformer, based on transformer T type equivalent electric circuit, the increment Delta u that can accurately calculate the 20Hz voltage and current of primary side by the increment Delta u and the Δ i of secondary side 20Hz voltage and current
sWith Δ i
s, by Δ u
sWith Δ i
sCan accurately calculate primary side ground fault resistance value.
The flow process of the intermittent injection type stator ground fault protection in the embodiment of the invention is as shown in Figure 4:
(1) at first detects the running frequency of generator, and preserve distribution transformer secondary voltage u and current i sampled data in some nT times complete cycle, wherein T is the cycle of operation of generator, the complete cycle that had both comprised several generator operation frequencies in the sampled data, comprise the complete cycle of at least one 20Hz again;
(2) after the time, inject the 20Hz power supply signal of identical time through nT, preserve corresponding distribution transformer secondary voltage u and current i sampled data simultaneously to generator;
(3) repeat (2), (3) process, realize that the 20Hz power supply intermittently injects generator;
(4) time interval nT that injects generator with the 20Hz power supply is the counting period, calculates the increment of distribution transformer secondary voltage u and current i sampled data respectively, i.e. Δ u=u (t)-u (t-nT), Δ i=i (t)-i (t-nT);
(5) calculate distribution transformer secondary voltage u and the increment Delta u of current i sampled data and the 20Hz component among the Δ i
With
(6) stator winding that calculates distribution transformer secondary side admittance Y and convert the ground fault resistance Rg of primary side over the ground:
When not considering the parameter influence of distribution transformer:
When considering the parameter influence of distribution transformer:
(7) computer according to set and the protection of storage with the ground fault resistance value of ground fault resistance high-set setting and low setting value and above-mentioned measuring and calculating relatively:
When being lower than the high setting value of earth resistance of protecting setting, the ground fault resistance value of above-mentioned measuring and calculating sends alarm signal;
When being lower than the low setting value of earth resistance that protection sets, the ground fault resistance value of above-mentioned measuring and calculating sends trip signal.
Work as the ground fault resistance value R that calculates in the present embodiment
gSend out alarm signal when being lower than the high setting value 5k Ω of protection, when the ground fault resistance value is lower than low setting value 500 Ω of protection, send out trip signal, obtain switching value output, carry out action by relay.
In additional power source intermittent injection type stator ground fault protection embodiment of the present invention; when starting, generator operates in 40Hz; when 1k Ω resistance generation earth fault; Fig. 5 is secondary voltage and the current increment that additional power source intermittent injection type stator ground fault protection of the present invention calculates; and the ground fault resistance value, result of calculation extremely approaches 1k Ω as can be seen, and result of calculation is not subjected to the influence of generator operation frequency; accuracy is very high, and the normal operation of protection is implemented alarm and protection to motor.
Claims (1)
1. stator grounding protection method of additional electric source intermittent injection type power generator is characterized in that it contains following steps successively:
Step (1) initialization:
Detect the running frequency of generator, and the time nT that uses when setting the voltage u that gathers the distribution transformer secondary side and current i according to detected running frequency, wherein, T is the cycle of operation of generator, n is a periodicity, determines in the following manner:
When the running frequency of generator was lower than 20Hz, n got 1～2,
When the running frequency of generator was higher than 20Hz, n got 2～5,
So that make the complete cycle that had both comprised several generator operation frequencies in the image data, comprise the complete cycle of at least one 20Hz again;
Step (2) is injected the 20Hz power supply neutral point of described generator via described distribution transformer secondary side winding;
Step (3) is gathered the voltage u of this distribution transformer secondary side with the voltage divider on the secondary side winding that is attempted by described distribution transformer, the current i of gathering this distribution transformer secondary side again with the current transformer on the secondary side winding that is serially connected in described distribution transformer, sampling time is nT, sampled data the intermittence of a described collection inject that the stator ground fault protection device switches through low pass filter, variable connector successively and analog-to-digital conversion after, be input among the CPU and preserve;
After time, the 20Hz power supply signal in described generator injects identical sampling time nT is preserved the voltage u of the distribution transformer secondary side that measures and the value of current i to step (4) simultaneously through nT;
Step (5) repeating step (3) and step (4) realize that the 20Hz power supply intermittently injects described generator;
Step (6) is the counting period with sampling time nT, calculates the increment Delta u and the Δ i of described voltage u and current i sampled data respectively:
Δu＝u(t)-u(t-nT)，Δi＝i(t)-i(t-nT)；
Step (7) the calculating 20Hz voltage u and the increment Delta u of current i sampled data, the component among the Δ i
The stator winding that step (8) is calculated as follows described distribution transformer secondary side is admittance Y over the ground:
Step (9) is calculated as follows the ground fault resistance R that converts primary side
g:
The described CPU of step (10) according to set and the protection of storage comes respectively with high setting value of ground fault resistance and the low setting value of earth resistance and step (9) in the ground fault resistance R that obtains
gCompare:
As described ground fault resistance R
gWhen being lower than the high setting value of ground fault resistance that protection sets, send alarm signal; As described ground fault resistance R
gBe lower than when protecting the earth resistance of setting to hang down setting value, send trip signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008101161202A CN101340082B (en) | 2008-07-04 | 2008-07-04 | Stator grounding protection method of additional electric source intermittent injection type power generator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008101161202A CN101340082B (en) | 2008-07-04 | 2008-07-04 | Stator grounding protection method of additional electric source intermittent injection type power generator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101340082A CN101340082A (en) | 2009-01-07 |
| CN101340082B true CN101340082B (en) | 2011-05-11 |
Family
ID=40214075
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2008101161202A Expired - Fee Related CN101340082B (en) | 2008-07-04 | 2008-07-04 | Stator grounding protection method of additional electric source intermittent injection type power generator |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101340082B (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101741063B (en) * | 2010-03-04 | 2012-05-23 | 国电南瑞科技股份有限公司 | Redundancy sampling calculation-based superposed square-wave voltage type rotor earth-fault protection method |
| EP2596373B1 (en) | 2010-07-19 | 2015-01-21 | ABB Technology AG | Device and method for detecting a ground fault |
| CN102170109A (en) * | 2010-12-29 | 2011-08-31 | 中国长江三峡集团公司 | Method for acquiring sample data window width for stator ground protection device |
| WO2012113440A1 (en) | 2011-02-21 | 2012-08-30 | Abb Research Ltd | Method and device for enhancing the reliability of generator ground fault detection on a rotating electrical machine |
| CN103050943B (en) * | 2012-07-04 | 2014-12-03 | 南京南瑞继保电气有限公司 | Generator injection-type stator ground protection method applicable to single-point and dual-point grounding systems |
| CN103795032A (en) * | 2012-10-29 | 2014-05-14 | 北汽福田汽车股份有限公司 | Detection device and detection method of motor stalling |
| CN104917148B (en) * | 2014-03-12 | 2018-03-30 | 南京南瑞继保电气有限公司 | A kind of generator injected type stator ground protection method and protection device |
| CN104897968B (en) * | 2015-05-14 | 2017-08-08 | 武汉市康达电气有限公司 | Mesh grounding impedance detecting method based on paraphase method of addition |
| CN104852355A (en) * | 2015-05-27 | 2015-08-19 | 北京四方继保自动化股份有限公司 | Injection-type stator earth-fault protection method without being affected by generator winding |
| CN105514937A (en) * | 2015-12-31 | 2016-04-20 | 中国长江电力股份有限公司 | Method for off-line setting injection stator ground protection |
| CN107944077A (en) * | 2017-10-23 | 2018-04-20 | 国电南瑞科技股份有限公司 | Generator injected type stator ground protection test model and method |
| CN109164387A (en) * | 2018-09-30 | 2019-01-08 | 国电南瑞南京控制系统有限公司 | Generator unit stator winding Injection Current measurement method based on big small-range CT |
| CN109324232A (en) * | 2018-11-02 | 2019-02-12 | 许继电气股份有限公司 | A kind of ground resistance measuring circuit of stator ground fault protection |
| CN109617017B (en) * | 2018-12-14 | 2020-02-21 | 许继电气股份有限公司 | Generator stator grounding protection system, method and device |
| CN112234579B (en) * | 2020-10-28 | 2022-07-01 | 天生桥二级水力发电有限公司天生桥水力发电总厂 | Injection type stator grounding protection method and system of large hydraulic generator |
-
2008
- 2008-07-04 CN CN2008101161202A patent/CN101340082B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN101340082A (en) | 2009-01-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101340082B (en) | Stator grounding protection method of additional electric source intermittent injection type power generator | |
| CN101414744B (en) | Grounding protection method for stator of dual-frequency injection type power generator | |
| CN1333503C (en) | Protection and fault positioning method for generator stator winding single-phase earthing | |
| CN102253283B (en) | A kind of distributed micro-grid grid-connected island detection method based on Wavelet Packet Energy Spectrum | |
| CN101975911B (en) | Earth fault judging method for overhead line fault indicator | |
| CN103050933B (en) | Based on the large-sized battery energy-accumulating power station interface protection method of one-terminal current Sudden Changing Rate | |
| CN103412207A (en) | Photovoltaic grid connected inverter island detection method based on negative sequence current injection | |
| CN103245879A (en) | Small current neutral grounding fault location method based on direction of transient state reactive power | |
| CN103149494B (en) | Three-phase power grid voltage short-circuit fault diagnosis method | |
| CN103954925A (en) | Fault recorder dynamic testing method based on RTDS real-time simulation | |
| CN104218526A (en) | Generator injection-type stator grounding protection method using segmented phase angle compensation | |
| CN102608499A (en) | Low-current line selection device and control method for inhibiting unbalanced current by way of differential filtration | |
| CN110854810B (en) | One-point grounding protection method for rotor of large synchronous phase modulator | |
| CN102005741A (en) | Distribution network line single phase earthing fault diagnosis and isolation method and device | |
| CN101593972B (en) | Fault line selection method for resonant grounded power distribution system by pattern spectrum | |
| CN105445585A (en) | Fault diagnosis method and system for primary loop of power grid | |
| CN104577999A (en) | Bus protection method and system based on transient-state zero-sequence current characteristic | |
| CN101846717A (en) | Low-current ground fault line selection device | |
| CN114441891A (en) | Power distribution network single-phase earth fault line selection method based on current signal similarity | |
| CN103107536B (en) | State estimation method for offshore oilfield group power grid | |
| CN103884930A (en) | Full bridge uncontrolled rectifier fault diagnosis method based on insulation monitoring | |
| CN105866592A (en) | System and method for acquiring dynamic reactive power compensation response waveforms | |
| CN103116116A (en) | Judging method and device of over line stoppage property of same pole double-circuit line with paralleling reactor | |
| CN101534009B (en) | Analysis method for operating characteristics of power-frequency variable directional protection of AC-DC interconnected power grid | |
| CN103513088B (en) | Electric power system alternating current magnitude of current sampled data validation checking method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20110511 Termination date: 20190704 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |