CN104518481A - Method for improving overvoltage protection sensitivity of generator-transformer unit - Google Patents
Method for improving overvoltage protection sensitivity of generator-transformer unit Download PDFInfo
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- CN104518481A CN104518481A CN201310459554.3A CN201310459554A CN104518481A CN 104518481 A CN104518481 A CN 104518481A CN 201310459554 A CN201310459554 A CN 201310459554A CN 104518481 A CN104518481 A CN 104518481A
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- protection
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- overvoltage
- overvoltage protection
- overexcitation
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Abstract
The invention provides a method for improving voltage protection sensitivity of generator-transformer unit. The method includes at least three steps: 1, decreasing a fixed action value of overvoltage protection to make sure overvoltage U of a wire of the generator-transformer unit is not greater than 1.2Un; 2, shortening delay time of overvoltage protection to make sure that the delay time t is (0.1-0.2)s; 3, setting overexcitation protection according to a set value of overvoltage protection, and using fixed time-lag overexcitation protection as backup for overvoltage protection and inverse time-lag overexcitation protection as backup for fixed time-lag protection. Under joint action of the three steps above, the problem that protection sensitivity is low when a generator stator experiences overvoltage can be effectively solved. Operation results show that after the steps are taken, the original features of overvoltage protection of the generator stator is unaffected, and the problem that stator overvoltage protection sensitivity is too low is thoroughly solved. Therefore, the problem that the high fixed value of stator overvoltage protection and excessive length of delay time cause worsened damaged condition of the generator-transformer unit is avoided.
Description
Technical field
The present invention relates to a kind of method improving the overvoltage protection action sensitivity of generator-transformer group wiring, belong to power system transformer substation resist technology field.
Background technology
For many years, once there is the fault of some overvoltage, overexcitation in the generator of transformer unit wiring, but overvoltage protection seldom has the record of correct operation.The incorrect operation of protection, and the behavior of delayed excision fault expands accident on the one hand, voltage protection does not play due effect on the other hand, adds unfavorable factor to accident analysis and process.Such as:
Rizhao power #3 unit, during no-load test, boosting has exceeded voltage margin, and be the rising that transformer characteristic limits voltage, generator voltage does not reach the setting value of overvoltage protection.
Xin Dian power plant #1 unit, when carrying out no-load test because the problem of static characteristic causes forced exciting action, there is overexcitation in unit, overprotection does not have action, crosses differential protection action chaser.
×× power plant unit, when carrying out short circuit test, switch trip when short circuit current reaches rated value, voltage raises, protection correct operation, but delay time
, oversize, a string equipment clean burn of generator transformer unit is ruined.The expansion of accident has not only increased the weight of power plant's loss, has also injured the safe operation of electrical network.
According to relay protection setting calculation directive/guide, the definite value that the overvoltage protection of generator transformer unit wiring unit generally adopts is as follows: voltage of adjusting,
; Delay time,
.This directive/guide is applicable to the unit of web frame on generator-circuit breaker, but is unsuitable for the unit of generator transformer unit wiring, because structure so is the rising that transformer characteristic limits voltage.This directive/guide applies to 2009 always, till the thinking of the test method of action sensitivity " improve generator super-voltage protection " finds application.
In electric power system, test the action behavior protected by fault is common thing; The present invention has tested the performance of voltage protection by fault together, thus proposes the illustration of protection improved though.
Summary of the invention
The present invention is directed to the problem that generator transformer unit wiring overvoltage fault protection insufficient sensitivity, responsiveness are too slow, provide one and can make the sensitive reaction of generator super-voltage protection, QA measure.
For achieving the above object, the invention provides following technical scheme.
Improve a method for transformer unit overvoltage protection sensitivity, it is characterized in that, at least comprise in following measures:
(1) reduce the action definite value of overvoltage protection, make the definite value of overvoltage protection
;
(2) shorten the delay time of overvoltage protection, make overvoltage protection delay time
;
(3) carry out adjusting of over-excitation protection according to the setting value of overvoltage protection, using the standby of overexcitation definite time protection as overvoltage protection, inverse time lag over-excitation protection is as the standby of definite time protection.Arrange as follows,
Overexcitation definite time protection setting value:
,
;
setting time is differential, gets
;
Inverse time lag over-excitation protection setting value:
,
.
If above 3 measures play a role jointly, the problem protecting delayed excision fault when stator overvoltage fault appears in generator just effectively can be solved, to reduce the degree of the damage of generator; Overvoltage protection band
time delay can escape the impact of transient process; Meanwhile, achieve the close fit of overvoltage protection and over-excitation protection, add reliability.Efficiently avoid that false protection, switch mis-jumping, signal are sent out by mistake, the series of problems of unit mistakenly stop thus.
Thus avoid equipment breakdown and expand the shock effect that electrical network is caused.Therefore, a kind of validity improving the method for generator super-voltage protection action sensitivity is confirmed.
The invention has the beneficial effects as follows; by the measure that the action definite value of reduction overvoltage protection, the delay time shortening overvoltage protection, reinforcement overvoltage protection coordinate with over-excitation protection; effectively can improve the sensitivity of overvoltage fault protection; shorten the action trip time of protection; avoid equipment breakdown to expand, thus avoid unnecessary loss.
Accompanying drawing explanation
Figure 1 shows that unit short circuit test primary system structure chart.
Figure 2 shows that transformer unit short circuit characteristic trial curve.
Figure 3 shows that transformer unit no-load characteristic test curve.
Figure 4 shows that generator numerical control system DCS records wave property curve.
Figure 5 shows that the characteristic of overvoltage protection and over-excitation protection.
Embodiment
Below in conjunction with accompanying drawing and embodiment, the invention will be further described.
For Rizhao power unit electrical test overexcitation; the present embodiment analyzes and solves the too slow example of generator transformer unit wiring overvoltage protection insufficient sensitivity, responsiveness; illustrate in the overvoltage protection of analysis generator-transformer group formula wiring system and over-excitation protection characteristic; determining overvoltage protection trip boundary, determine the indexs such as generator super-voltage protection operate time; and determining the reasonable coordination of generator super-voltage protection and over-excitation protection, set up the work that rational index system aspect is done.
At the scene to the operation conditions of generator-transformer system; generator super-voltage protection and over-excitation protection characteristic are checked; transformer problem of temperature rise is analyzed; the chromatogram of transformer oil is checked, determines the index of overvoltage protection operation voltage value and operate time.
In conjunction with the conclusion that other power plants draw, consider that stator ground fault protection need escape the factor of Effect of Transient Component, finally determine, (1) reduces the action definite value of overvoltage protection, the definite value of overvoltage protection
; (2) delay time of overvoltage protection is shortened, overvoltage protection delay time
; (3) carry out adjusting of over-excitation protection according to the setting value of overvoltage protection, using the standby of overexcitation definite time protection as overvoltage protection, inverse time lag over-excitation protection is as the standby of definite time protection.
The present invention also analyzes the meaning of research diverting coefficient, can determine the most serious impaired equipment, to take treatment measures when overvoltage, overexcitation appear in generator transformer unit system.From test data, the current distributing of generator transformer unit short circuit manner and the shunting difference of unloaded manner overexcitation very large.It will be clear that the overexcitation problem under analysis unloaded manner, foundation should be split into unloaded overexcitation; Analyze the overexcitation problem of mode of loading, should with reference to short circuit current diverting coefficient; Analyze the electric current cloth under short-circuit conditions, should be as the criterion with short circuit current diverting coefficient.
In Rizhao power #4 startup of unit process, because the winding of protection, measurement, excitation 57V is all connected into open-delta 33V side by generator outlet TV by mistake, the voltage that during generator boosting like this, meter meter etc. are experienced reduces
doubly, transformer unit overexcitation when causing unit unloaded pressure build-up test.One group of data of surveying at that time are: rated voltage U=20kV; Unloaded specified 1480 A of exciter current of generator IL=3823A(); Unloaded specified 130 V of exciting voltage UL=353V(); The unloaded specified 80A of dynamo current I=2392A(); Generator measurement voltage U=13.81kV, virtual voltage is then 13.81
kV=23.92kV, overexcitation multiple is 23.92kV/20kV=1.196, and voltage waveform is seriously saturated.Over-excitation protection does not have action, because over-excitation protection reflection U/F, and numerical value setting value not enough far away.After changing TV wiring, parameter is normal.
One, phenomenon of the failure
On November 19th, 2008, Rizhao power #4 startup of unit, carries out in generator no-load test process, the generator voltage U=13.81kV detected; Dynamo current I=2392A; Exciting voltage UL=353V; Exciting current IL=3823A; The problem shown is as follows.
1, generator open-circuit excitation exceeds standard
Open-circuit excitation current rating should be 1480A, but actual current IL=3823A;
Off-load excitation voltage is specified should be 130 V, but actual exciting voltage UL=353V.
2, generator no-load current exceeds standard
Generator no-load current should be no more than 100A under normal circumstances, but actual generator electric current I=2392A, show obvious overexcitation symbol.
3, over-excitation protection does not have action
Over-excitation protection does not have action, manual operation demagnetization.
Definite identification is made to unit overexcitation, unit overexcitation and overvoltage protection are accomplished that correct use is the key point of problem.
Doubtful point is analyzed: series of parameters relation when overexcitation of the main transformer that (1) is in parallel, HV Auxiliary Transformer, desulfurization transformer and the extent of damage confirm; (2) protection problem during transformer overexcitation, crucial moment is by which kind of protection act.
Two, checking process
Comprise the inspection of unit primary equipment, the inspection of short circuit current diverting coefficient, open-circuit excitation current distributing coefficient checks, DCS records wave property inspection and electrical secondary system inspection.
1, the inspection of unit primary equipment
Because overexcitation phenomenon problem has appearred in unit, in order to confirm whether fault so causes the damage of equipment, carry out a series of inspection work.
(1) the insulation inspection of transformer
Carried out insulating checking to #4 main transformer, HV Auxiliary Transformer, desulfurization transformer, result is normal.
(2) the chromatogram inspection of transformer
And the chromatogram of above-mentioned transformer is checked, data see the following form.
2, the inspection of short circuit current diverting coefficient
The inspection that can complete short circuit current diverting coefficient is tested in conjunction with sending out variable resistance short-circuit characteristic.
Transformer unit system configuration is shown in Fig. 1, and in figure, G is generator, and T is main transformer, and T1 is HV Auxiliary Transformer, and T2 is desulfurization transformer, and 204 is 220kV side circuit breaker, and 601,602,603 is 6kV side circuit breaker.
(1) short-circuit characteristic test
Carry out the test of transformer unit short circuit characteristic, must close 204 switches, disconnects 601,602,603 switches, then manually increase magnetic, generator unit stator electric current is raised to about 21169A, and then demagnetize, and electric current is dropped to zero, admission generator short circuit characteristic
, short-circuit characteristic is shown in Fig. 2.
for exciter current of generator.
(2) short circuit current breadth coefficient test
Carry out the inspection of short circuit current diverting coefficient, must close 204,601,602,603 switches simultaneously, then manually increases magnetic, generator unit stator electric current is raised to 5169A, now HV Auxiliary Transformer primary current 635A, desulfurization primary side current of transformer 286A, main transformer primary current 4248A.
The calculating of short circuit current diverting coefficient:
Main transformer electric current
, diverting coefficient:
;
Station transformer electric current
, current coefficient:
;
Desulfurization transformer current
, current coefficient:
.
Above-mentioned electric current compares with rated value:
Dynamo current
with rated value
:
;
Main transformer electric current
with rated value
:
;
High factory time-dependent current
with rated value
:
;
Desulfurization time-dependent current
with rated value
:
.
3, open-circuit excitation current distributing coefficient checks
The inspection that can complete no-load current diverting coefficient is tested in conjunction with sending out variable resistance no-load characteristic.
Generatortransformer unit no-load test system is see Fig. 1.Carry out transformer unit no-load characteristic test and the inspection of no-load transformer current distributing coefficient, 204,601,602,603 switches all must be disconnected.Now main transformer, high factory become and desulfurization change, three parallel operation of transformers.
(1) no-load characteristic test
Generator voltage is risen to rated voltage 21kV from zero, then is down to zero, admission generator no-load characteristic
, no-load characteristic is shown in Fig. 3.Wherein
generator voltage is
exciting current.
(2) open-circuit excitation current distribution factor test
Manual increasing magnetic, is raised to 20kV by generator unit stator voltage, now generator unit stator electric current 220 A, main transformer primary current 55A, HV Auxiliary Transformer primary current 60A, desulfurization primary side current of transformer 105A.
Unloaded overexcitation Calculation of the shunted current:
Main transformer coefficient:
;
Station transformer coefficient:
;
Desulfurization transformer coefficient:
.
According to above-mentioned diverting coefficient, as dynamo current 2392A,
Main transformer electric current:
;
Station transformer electric current:
;
Desulfurization transformer current:
.
According to diverting coefficient 55A/60A/105A, when the unloaded overexcitation of transformer unit, generator 2392A electric current enters desulfurization close to half and becomes, and the overexcitation that desulfurization becomes is the most serious.
4, DCS records wave property inspection
Generator numerical control system DCS records wave property curve and sees Fig. 4, as shown in Figure 4, and unloaded specified 1480 A of exciter current of generator IL=3823A(); Unloaded specified 130 V of exciting voltage UL=353V(); The unloaded specified 80A of dynamo current I=2392A(); Generator measurement voltage U=13.81kV, virtual voltage is then 13.81
kV=23.92kV, overexcitation multiple is 23.92kV/20kV=1.196, and voltage waveform is seriously saturated.
5, the inspection of electrical secondary system
Comprise the inspection of the checked excitatory relay protective scheme of over-excitation protection definite value, the inspection of TV secondary circuit.
(1) inspection of over-excitation protection definite value
Machine over-excitation protection check result sees the following form:
Specified time definite value is too low, and its characteristic is correct.
(2) inspection of over-excitation protection logic
Over-excitation protection action logic is correct, but control word input is 0, and that is over-excitation protection does not drop into.
(3) inspection of TV secondary circuit
Check and find, the winding of protection, measurement, excitation 57V is all connected into open-delta 33V side by generator outlet TV wiring by mistake, and the voltage that meter meter etc. are experienced when generator boosts reduces
doubly, transformer unit overexcitation when causing unit unloaded pressure build-up test, over-excitation protection does not but have action.
Three, case study
Due to TV wiring error cause token measure inaccurate, protection sampling is inaccurate, relay protective scheme arranges mistake and causes excitatory protection not drop into, transformer unit overexcitation when causing unit unloaded pressure build-up test; The reason of TV second loop return wiring mistake is TV cabinet terminal mark mistake; The reason that relay protective scheme arranges mistake is artificial factor, and conclusion is very clear and definite.What be worth analyzing is the series of problems of overexcitation.
1, the meaning of diverting coefficient is studied
The meaning of research diverting coefficient is can determine the most serious impaired equipment when overvoltage, overexcitation appear in generator transformer unit system, to take treatment measures.From test data, the current distributing of generator transformer unit short circuit manner and the shunting difference of unloaded manner overexcitation very large.It will be clear that the overexcitation problem under analysis unloaded manner, foundation should be split into unloaded overexcitation; Analyze the overexcitation problem of mode of loading, should with reference to short circuit current diverting coefficient; Analyze the current problems under short-circuit conditions, should be as the criterion with short circuit current diverting coefficient.
2, overexcitation is on the analysis of the impact of equipment:
Because generator overvoltage multiple is not high, therefore overexcitation can not be considered the impact of generator.The impact analysis of overexcitation to transformer is as follows.
(1) overexcitation of desulfurization change is the most serious
Difference is there is between the short circuit current diverting coefficient of transformer and open-circuit excitation diverting coefficient.
According to the conclusion that the short circuit current diverting coefficient of transformer draws be: the order Shi Gao factory that 3 transformers are saturated becomes (43%), desulfurization becomes (39%), main transformer (18%), and what that is damage at first is HV Auxiliary Transformer.
According to the conclusion that the open-circuit excitation diverting coefficient of transformer draws be: three parallel operation of transformers, main transformer, high factory become and desulfurization change, its diverting coefficient is 55A/60A/105A, and become so generator 2392A electric current enters desulfurization close to half, the overexcitation that desulfurization becomes is the most serious.
During the no-load test of generator-transformer, be only definite by the computational analysis of open-circuit excitation diverting coefficient, should take this as the standard.
(2) voltage relationship of both sides during transformer overexcitation
During transformer overexcitation, the voltage of both sides is still followed
; When boosting after transformer overexcitation, the voltage of both sides is then followed again
, so will note in advance to transformer degaussing.In above formula
for primary voltage of transformer,
for transformer secondary voltage,
for transformer secondary remanent magnetism voltage.
(3) during overexcitation on the impact of iron core
In principle, can produce eddy current during transformer overexcitation in iron core, eddy current produces heat, temperature unshakable in one's determination is raised, during temperature exceeding standard, damages insulation, therefore the multiple of overexcitation and time, have strict requirement for each transformer, its index is relevant with material technology.Overexcitation allows the time to check in from curve according to multiple.
This time during overexcitation, temperature unshakable in one's determination raises 1 ° of C.
3, the calculating of transformer overexcitation multiple
Calculate by generator outlet voltage, overexcitation multiple is
;
Calculate by generator excitation voltage, overexcitation multiple is
;
Calculate by exciter current of generator, overexcitation multiple is
;
Above 3 kinds of algorithms 3 results, correct should be
, relevant case study should be taken this as the standard.
4, unit overexcitation and overvoltage problem analysis
Comprise the following aspects.
(1) unit overexcitation and overvoltage problem and the generator transformer unit mode of connection closely related
Unit overexcitation and overvoltage problem and generator transformer unit formula connected mode closely related, according to the no-load characteristic of generator transformer unit, voltage is greater than 1.05
time enter saturation region, then when increasing exciting current, voltage is not in obvious rising, and voltage max is less than 1.20
; Independent generator, according to the no-load characteristic of generator, voltage is greater than 1.30
time just enter saturation region.
(2) speed of boosting determines the problem of the saturated of transformer and system overvoltage
Boost at a slow speed, transformer is saturated in time, and system does not exist superpotential problem; Rapid pressure, transformer is unsaturated in time, and system exists superpotential problem.Such as, when transformer unit does short circuit test, there is the situation of open circuit when dynamo current arrives rated value just so.Unit short circuit test primary system structure is see Fig. 1.
(3) unit overexcitation and overvoltage problem
Unit overexcitation masks overvoltage, and during boosting, transformer enters saturation region at a slow speed, and system does not exist superpotential problem, but has occurred overexcitation problem.Therefore, the definite value of the generator super-voltage protection of the generator transformer unit mode of connection can not be greater than
.
5, the problem of tuning of overvoltage protection
Run and show with result of the test, if the system of generator transformer unit wiring, overvoltage protection adopts voltage of adjusting
; Delay time
setting value, then overvoltage protection performs practically no function.Adopt the overvoltage protection of this setting value only to carry out short circuit test at unit, switch trip when short circuit current is greater than certain numerical value, major loop disconnects; now because transformer does not reach capacity state; system voltage raises, the effect of overvoltage protection competence exertion, but delay time now should be
.Visible, the system of generator transformer unit wiring, adjust voltage and the delay time of overvoltage protection must be changed.
6, the problem of tuning of over-excitation protection
The setting principle of over-excitation protection is as follows.
Obviously, the setting value of over-excitation protection reality does more careful than this requirement.However, setting value still exists with the actual problem disconnected.
(1) there is dead band in anti-time limit characteristic high-set setting section
Anti-time limit characteristic, when generator frequency F value stabilization
section do not act on, now rely on low definite value action section to play a role.
(2) specified time and inverse time lag over-excitation protection mismate
Specified time and inverse time lag over-excitation protection, 1.3 time, delay time difference is larger.
(3) overvoltage protection and over-excitation protection mismate
The characteristic curve of generator transformer unit overvoltage protection and over-excitation protection is shown in Fig. 5.
Four, the precautionary measures
Comprise the treatment measures after the precautionary measures of overexcitation, overexcitation, improve the sensitivity of generator super-voltage protection action and realize the close fit of overvoltage protection and over-excitation protection.
1, the precautionary measures of overexcitation, comprise following two aspects.
(1) proper use of over-excitation protection
Before over-excitation protection is put into operation, must test in strict accordance with the regulation of inspection procedure, ensure that the performance index of protection reach the requirement of design.
(2) pinpoint the problems and process in time
In unit starting process of the test, when adjusting generator voltage, the indexs such as generator voltage, dynamo current, exciting voltage, exciting current should be paid close attention to, each defect that immediate analysis occurs with process, can not overuse equipment.
2, the treatment measures after overexcitation, comprise following two aspects.
(1) to transformer degaussing
Because when boosting after transformer overexcitation, the voltage of both sides is followed again
, so must to transformer degaussing before boosting again.There are following two kinds of demagnetizing methods:
Short circuit degaussing method: namely adopt the method for transformer unit short circuit test to carry out degaussing;
Leave standstill degaussing method: namely adopt standing method, transformer is left standstill more than 24 hours, allows its remanent magnetism is very long decays to 0.
(2) transformer oil sample is checked
See the result that oil sample checks, the numerical value of total hydrocarbon can not exceed standard, otherwise Inspection and analysis it.
3, improve the sensitivity of generator super-voltage protection action, comprise following two aspects.
(1) the action definite value of overvoltage protection is reduced
Reduce the definite value of the overvoltage protection of generator transformer unit wiring, make
.
(2) delay time of overvoltage protection is shortened
Voltage protection delay time is compressed, makes
.
4, the close fit of overvoltage protection and over-excitation protection is realized.Overvoltage protection and over-excitation protection are carried out close fit, can solve the transformer unit mode of connection, voltage is limited and protects QA contradiction.Owing to no longer there is high voltage, therefore, over-excitation protection is made good use of, with to make good use of overvoltage protection equally important.The characteristic of overvoltage protection and over-excitation protection is shown in Fig. 2.
Basic ideas are, according to the setting value of overvoltage protection, carry out adjusting of over-excitation protection, and using the standby of overexcitation definite time protection as overvoltage protection, inverse time lag over-excitation protection is as the standby of definite time protection.Arrange as follows:
Overexcitation definite time protection setting value:
,
;
setting time is differential, gets
;
Inverse time lag over-excitation protection setting value:
,
.
By reference to the accompanying drawings the specific embodiment of the present invention is described although above-mentioned; but not limiting the scope of the invention; one of ordinary skill in the art should be understood that; on the basis of technical scheme of the present invention, the various amendment that those skilled in the art do not need creative work to make or distortion are in protection scope of the present invention.
Claims (2)
1. improve a method for transformer unit overvoltage protection sensitivity, it is characterized in that: at least comprise in following measures:
(1) the action definite value of overvoltage protection is reduced;
Result of the test shows, the overvoltage of generator transformer unit wiring
,
for voltage of adjusting, the definite value of protection therefore must be reduced;
(2) delay time of overvoltage protection is shortened;
Operating experience for many years shows, overvoltage protection protects very reliably, does not have the record of misoperation, therefore can shorten its delay time, make delay time in normal operation
,
for setting time;
(3) coordinating of overvoltage protection and over-excitation protection is strengthened;
Basic ideas are, the setting value according to overvoltage protection carries out adjusting of over-excitation protection, and using the standby of overexcitation definite time protection as overvoltage protection, inverse time lag over-excitation protection, as the standby of definite time protection, arranges as follows,
Overexcitation definite time protection setting value:
,
;
setting time is differential, gets
;
Inverse time lag over-excitation protection setting value:
,
.
2. a kind of method improving the sensitivity of transformer unit overvoltage protection as claimed in claim 1, is characterized in that: take above three measures simultaneously.
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|---|---|---|---|
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030102848A1 (en) * | 2001-11-30 | 2003-06-05 | Mitsubishi Denki Kabushiki Kaisha | Excitation controller for synchronous machine |
| CN101707353A (en) * | 2009-12-02 | 2010-05-12 | 南京南瑞继保电气有限公司 | Inverse time lag over excitation protection method of generator and transformer |
| CN201608682U (en) * | 2009-12-14 | 2010-10-13 | 天水电气传动研究所有限责任公司 | Digital voltage regulator of synchronous generator |
-
2013
- 2013-10-08 CN CN201310459554.3A patent/CN104518481A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030102848A1 (en) * | 2001-11-30 | 2003-06-05 | Mitsubishi Denki Kabushiki Kaisha | Excitation controller for synchronous machine |
| CN101707353A (en) * | 2009-12-02 | 2010-05-12 | 南京南瑞继保电气有限公司 | Inverse time lag over excitation protection method of generator and transformer |
| CN201608682U (en) * | 2009-12-14 | 2010-10-13 | 天水电气传动研究所有限责任公司 | Digital voltage regulator of synchronous generator |
Non-Patent Citations (1)
| Title |
|---|
| 吴跨宇等: ""基于空载误强励灭磁对发电机过电压保护整定的研究"", 《电力系统保护与控制》 * |
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