CN105403776A - Test method of low voltage ride-through capability of frequency converter based on magnetic powder brake - Google Patents
Test method of low voltage ride-through capability of frequency converter based on magnetic powder brake Download PDFInfo
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- CN105403776A CN105403776A CN201510563179.6A CN201510563179A CN105403776A CN 105403776 A CN105403776 A CN 105403776A CN 201510563179 A CN201510563179 A CN 201510563179A CN 105403776 A CN105403776 A CN 105403776A
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Abstract
The invention discloses a test method of the low voltage ride-through capability of a frequency converter based on a magnetic powder brake. The magnetic powder brake is employed as the simulation load of a coal feeder motor and a powder feeder motor, the loads carried by the coal feeder motor and the powder feeder motor are constant-torque loads, the output brake torque of the magnetic powder brake and field current are in a good linear relation and are irrelevant to the rotating speed or the slip, and the constant torque characteristic is represented in the specific field current. The magnetic powder brake is employed as the simulation load of the coal feeder motor and the powder feeder motor so that the low voltage ride-through capability of the frequency converter in the similar practical operation condition can be tested.
Description
Technical field
The present invention relates to a kind of method of testing of the frequency converter low voltage ride-through capability based on magnetic powder brake.
Background technology
So-called frequency converter low voltage ride-through capability, refer to transient state that frequency converter and power supply object-based device external fault or disturbance cause, dynamically or long time power primary voltage is reduced in the low voltage crossing district of regulation time, can reliable power supply, ensure the safe operation of power supply object.At present, fuel-burning power plant all configures a large amount of subsidiary engine and is usually in underload and variable load operation state, by installing frequency conversion speed-adjusting system additional to subsidiary engine, effectively can improve energy-saving benefit.But; low pressure subsidiary engine is as feeder, machine supplying powder etc.; due to heavier loads; frequency conversion speed-adjusting system " wink stops " function is inapplicable; and do not possess automatic power frequency switching bypass, when there is Voltage Drop, frequency conversion system can be shut down in locking; cause the Important Auxiliary equipment such as feeder, machine supplying powder device to be shut down, and then cause power plant generation boiler shutdown, compressor emergency shutdown accident.
Can be found by several crash analyses of domestic generation; during electric network fault main protection dynamic by back-up protection excision fault or reclosing in permanent fault, start large-scale house-service equipment or the abnormal low-voltage of service power all can cause frequency converter electrical source of power low-voltage; boiler shutdown, compressor emergency shutdown accident that this type of Station Service Electrical-Energy Voltage Drop causes, have a strong impact on power plant, power network safety operation.In January, 2013; State Grid Corporation of China hereafter requires investigation power station auxiliary frequency converter low voltage ride-through capability; for the unit not meeting low voltage ride-through capability requirement; low voltage ride-through capability transformation should be carried out; and after transformation, complete low voltage ride-through capability test job; guarantee that unit possesses certain low voltage ride-through capability, ensure the safe and stable operation of unit.
The frequency converter low voltage ride-through capability method of testing that current each province adopts all adopts voltage sag generator analog inverter input voltage to fall, and records frequency converter AC-input voltage, ac output voltage and DC bus-bar voltage.This test job may cause frequency converter locking to shut down; carry out during general selection compressor emergency shutdown; between down period; feeder, machine supplying powder motor are difficult to band actual loading and run; current way allows feeder, machine supplying powder motor no-load run; i.e. motor idle running or only belt leather tape running, its low voltage ride-through capability test result only reflects result during no-load running, cannot reflect actual conditions during unit actual motion.Particularly carry out low voltage ride-through capability test after transformation, if only adopt the motor of no-load running as load, its test result is difficult to low voltage ride-through capability when guarantee unit normally runs.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of method of testing of the frequency converter low voltage ride-through capability based on magnetic powder brake.
The present invention is achieved through the following technical solutions.
Based on a method of testing for the frequency converter low voltage ride-through capability of magnetic powder brake, step comprises:
(1) arranging voltage sag generator is serially connected with between auxiliary bus bar and tested subsidiary engine frequency converter, tested subsidiary engine frequency converter exchanges and exports tested electric motor of auxiliary machine to, the output shaft that magnetic powder brake connects tested motor is set, circuit breaker Q 0, circuit breaker Q 1 are set between auxiliary bus bar and voltage sag generator, between voltage sag generator and tested subsidiary engine frequency converter, circuit breaker Q 2 is set, stored digital oscillograph is set, connects the AC-input voltage end of tested subsidiary engine frequency converter, ac output voltage end, DC+, DC-respectively;
(2) start stored digital oscillograph, select stored digital oscillograph passage and coupling scheme, voltage bound parameter are set;
(3) circuit breaker Q 0, the circuit breaker Q 1 of closed auxiliary bus bar, voltage sag generator is obtained electric, the display of voltage sag generator input voltage, three-phase pilot lamp is normal, according to voltage dip simulated condition, the voltage dip time is set, fall number of times temporarily, and select corresponding isolating switch to export according to falling magnitude of voltage temporarily;
(4) close circuit breaker Q2, check dight stores oscillograph AC-input voltage, the display of frequency changer direct current bus voltage is normal;
(5) according to tested subsidiary engine frequency converter on the spot or distant place control mode, arrange frequency converter initiation culture, and start frequency converter, check dight stores oscillograph DC bus-bar voltage, ac output voltage display is normal;
(6) progressively increase magnetic powder brake exciting curent, and monitor frequency converter AC input current, until input current is increased to input current when frequency converter normally runs with clamp table;
(7) storage record wave mode is started, click voltage sag generator panel obtains and falls button temporarily, according to the voltage dip number of times arranged in (3), temporarily fall the time and temporarily drawdown degree analog voltage fall temporarily, terminate and after recovering normal voltage, terminate to store and record wave mode falling temporarily;
(8) recorded the voltage dip of ripple record by storage during, the situation of change of tested subsidiary engine frequency changer direct current bus voltage, ac output voltage can judge whether tested subsidiary engine frequency converter possesses the low voltage ride-through capability of index request.
Further, voltage sag generator at least should be able to simulate following three kinds of operating modes: 1) stable state low voltage crossing district: converter power supply primary voltage amplitude is down to rated voltage 90% temporarily, duration 60s; 2) dynamic low voltage crossing district: converter power supply primary voltage amplitude is down to rated voltage 60% temporarily, duration 5s; 3) transient state low voltage crossing district: converter power supply primary voltage amplitude is down to rated voltage 20% temporarily, duration 0.5s.
Further, the retarding torque produced during electric motor of auxiliary machine actual motion is calculated by following formula:
T
M＝9500*P
M/n
M；
Wherein P
mfor motor output rating, n
mfor motor rated speed, motor and magnetic powder brake rotating ratio are n
m/ n
z=k, wherein n
zfor magnetic powder brake rotating speed, k value can ensure that it runs reliably and with long-term adjust higher than minimum speed according to magnetic powder brake rotating speed.
Further, can be similar to the retarding torque that magnetic powder brake should produce is:
T
Z＝k*T
M。
Magnetic powder brake torque, selection of speed are carried out exciting curent after selecting and are chosen:
Frequency converter input three-phase alternating current by actual measurement and when recording feeder actual motion, and when carrying out low voltage ride-through capability test, start after tested frequency converter makes frequency converter band magnetic powder brake normally run, progressively increase magnetic powder brake exciting curent, monitoring frequency converter input three-phase alternating current simultaneously, keeping when reaching actual motion value exciting curent constant.The retarding torque that magnetic powder brake produces under this exciting curent is identical with during actual motion.
Beneficial effect of the present invention:
Adopt magnetic powder brake as the fictitious load of feeder, machine supplying powder motor, because feeder, machine supplying powder motor institute bringing onto load are constant torque load, and the output retarding torque of magnetic powder brake and exciting current are good linear relation and have nothing to do with rotating speed or slippage, in constant torque characteristic under specific exciting current.Adopt magnetic powder brake as the fictitious load of feeder, machine supplying powder motor, can test out close to the frequency converter low voltage ride-through capability under practical operation situation.
Accompanying drawing explanation
Fig. 1 is test wiring diagram of the present invention.
Embodiment
According to drawings and embodiments the present invention is described in further detail below.
As shown in Figure 1, voltage sag generator is serially connected with between auxiliary bus bar and tested frequency converter system testing wiring diagram, and tested frequency converter exchanges and exports tested electric motor of auxiliary machine to, and magnetic powder brake connects the output shaft of tested motor.Because magnetic powder brake maximum permissible speed is generally lower than tested electric motor of auxiliary machine rotor speed, on motor and magnetic powder brake, belt pulley can be installed, and by belt, motor different for rotating speed be connected with magnetic powder brake.
Because test needs, this measuring technology needs voltage sag generator simulation plant busbar voltage to fall, according to " large turbine-generator set one class subsidiary engine frequency converter high-low voltage crossing technology specification ", voltage sag generator at least should be able to simulate following three kinds of operating modes: 1) stable state low voltage crossing district: converter power supply primary voltage amplitude is down to rated voltage 90% temporarily, duration 60s; 2) dynamic low voltage crossing district: converter power supply primary voltage amplitude is down to rated voltage 60% temporarily, duration 5s; 3) transient state low voltage crossing district: converter power supply primary voltage amplitude is down to rated voltage 20% temporarily, duration 0.5s.Voltage sag generator normally exports as specified auxiliary bus bar voltage, and output LOW voltage when falling temporarily, recovers specified station-service voltage after setting-up time.
Stored digital oscillograph passes through and connects frequency converter AC-input voltage, ac output voltage and DC bus-bar voltage test and record tested subsidiary engine frequency converter working condition, can determine whether tested subsidiary engine frequency converter possesses low voltage ride-through capability by the voltage waveform of record.、
Because the magnetic powder brake of continuous working runs under the slippage condition being in 100%, the slip power of magnetic powder brake can be approximately the output power of motor, the selection of magnetic powder brake according to allowable sliding power and motor speed, and can retain certain nargin.
Motor institute bringing onto load is constant torque load, therefore the retarding torque produced during electric motor of auxiliary machine actual motion calculates by following formula:
T
M＝9500*P
M/n
M
Wherein P
mfor motor output rating (unit is kW), n
mfor motor rated speed (unit is rpm).Because motor is connected by belt with magnetic powder brake, motor and magnetic powder brake rotating ratio are n
m/ n
z=k, wherein n
zfor magnetic powder brake rotating speed, k value can suitably adjust, and the target of adjustment is higher than minimum speed, magnetic powder brake rotating speed ensures that it runs reliably and with long-term.
Can be similar to the retarding torque that magnetic powder brake should produce is:
T
Z＝k*T
M
By consulting magnetic powder brake retarding torque and exciting curent relation can determine the exciting curent that magnetic powder brake should apply.
According to magnetic powder brake exciting current and the relation exporting retarding torque, progressively increase magnetic powder brake exciting curent, make it export the retarding torque produced when retarding torque reaches feeder actual motion.Frequency converter input three-phase alternating current is recorded when feeder normally runs by actual measurement when practical operation, when tested frequency converter starts, progressively increase magnetic powder brake exciting curent, monitoring frequency converter input three-phase alternating current simultaneously, keeping when reaching actual motion value exciting curent constant.
Testing procedure and method
1) wiring connection is carried out by system shown in Figure 1 test pattern.
2) start stored digital oscillograph, select stored digital oscillograph passage and the parameter such as coupling scheme, voltage bound is set.
3) closed auxiliary bus bar circuit breaker Q 0, Q1, make voltage sag generator obtain electric, and the display of voltage sag generator input voltage, three-phase pilot lamp is normal.According to different voltage dip simulated conditions, the voltage dip time is set, falls number of times temporarily, and select corresponding isolating switch to export according to falling magnitude of voltage temporarily.
4) close circuit breaker Q2, check dight stores oscillograph AC-input voltage, the display of frequency changer direct current bus voltage is normal.
5) according to frequency converter on the spot or distant place control mode, arrange frequency converter initiation culture, and start frequency converter, check dight stores oscillograph DC bus-bar voltage, ac output voltage display is normal.
6) progressively increase magnetic powder brake exciting curent, and monitor frequency converter AC input current, until input current is increased to input current when frequency converter normally runs with clamp table.
7) storage record wave mode is started, click voltage sag generator panel obtains and falls button temporarily, according to step 3) in arrange voltage dip number of times, temporarily fall the time and temporarily drawdown degree analog voltage fall temporarily, terminate and after recovering normal voltage, terminate to store and record wave mode falling temporarily.
8) recorded the voltage dip of ripple record by storage during, the situation of change of frequency changer direct current bus voltage, ac output voltage can judge whether tested frequency converter possesses the low voltage ride-through capability of index request.
Above-described embodiment, only for technical conceive of the present invention and feature are described, its object is to allow the personage being familiar with this art can understand content of the present invention and be implemented, can not limit the scope of the invention with this.All equivalences done according to Spirit Essence of the present invention change or modify, and all should be encompassed in protection scope of the present invention.
Claims (5)
1., based on a method of testing for the frequency converter low voltage ride-through capability of magnetic powder brake, it is characterized in that, step comprises:
(1) arranging voltage sag generator is serially connected with between auxiliary bus bar and tested subsidiary engine frequency converter, tested subsidiary engine frequency converter exchanges and exports tested electric motor of auxiliary machine to, the output shaft that magnetic powder brake connects tested motor is set, circuit breaker Q 0, circuit breaker Q 1 are set between auxiliary bus bar and voltage sag generator, between voltage sag generator and tested subsidiary engine frequency converter, circuit breaker Q 2 is set, stored digital oscillograph is set, connects the AC-input voltage end of tested subsidiary engine frequency converter, ac output voltage end, DC+, DC-respectively;
(2) start stored digital oscillograph, select stored digital oscillograph passage and coupling scheme, voltage bound parameter are set;
(3) circuit breaker Q 0, the circuit breaker Q 1 of closed auxiliary bus bar, voltage sag generator is obtained electric, the display of voltage sag generator input voltage, three-phase pilot lamp is normal, according to voltage dip simulated condition, the voltage dip time is set, fall number of times temporarily, and select corresponding isolating switch to export according to falling magnitude of voltage temporarily;
(4) close circuit breaker Q2, check dight stores oscillograph AC-input voltage, the display of frequency changer direct current bus voltage is normal;
(5) according to tested subsidiary engine frequency converter on the spot or distant place control mode, arrange frequency converter initiation culture, and start frequency converter, check dight stores oscillograph DC bus-bar voltage, ac output voltage display is normal;
(6) progressively increase magnetic powder brake exciting curent, and monitor frequency converter AC input current, until input current is increased to input current when frequency converter normally runs with clamp table;
(7) storage record wave mode is started, click voltage sag generator panel obtains and falls button temporarily, according to the voltage dip number of times arranged in (3), temporarily fall the time and temporarily drawdown degree analog voltage fall temporarily, terminate and after recovering normal voltage, terminate to store and record wave mode falling temporarily;
(8) recorded the voltage dip of ripple record by storage during, the situation of change of tested subsidiary engine frequency changer direct current bus voltage, ac output voltage can judge whether tested subsidiary engine frequency converter possesses the low voltage ride-through capability of index request.
2. the method for testing of the frequency converter low voltage ride-through capability based on magnetic powder brake according to claim 1, it is characterized in that, voltage sag generator at least should be able to simulate following three kinds of operating modes: 1) stable state low voltage crossing district: converter power supply primary voltage amplitude is down to rated voltage 90% temporarily, duration 60s; 2) dynamic low voltage crossing district: converter power supply primary voltage amplitude is down to rated voltage 60% temporarily, duration 5s; 3) transient state low voltage crossing district: converter power supply primary voltage amplitude is down to rated voltage 20% temporarily, duration 0.5s.
3. the method for testing of the frequency converter low voltage ride-through capability based on magnetic powder brake according to claim 1, is characterized in that, magnetic powder brake torque, selection of speed are as follows:
The retarding torque produced during electric motor of auxiliary machine actual motion is calculated by following formula:
T
M＝9500*P
M/n
M；
Wherein P
mfor motor output rating, n
mfor motor rated speed, motor and magnetic powder brake rotating ratio are n
m/ n
z=k, wherein n
zfor magnetic powder brake rotating speed, k value can ensure that it runs reliably and with long-term adjust higher than minimum speed according to magnetic powder brake rotating speed.
4. the method for testing of the frequency converter low voltage ride-through capability based on magnetic powder brake according to claim 3, is characterized in that, can be similar to the retarding torque that magnetic powder brake should produce to be:
T
Z＝k*T
M。
5. the method for testing of the frequency converter low voltage ride-through capability based on magnetic powder brake according to claim 3, is characterized in that, magnetic powder brake torque, selection of speed are carried out exciting curent after selecting and chosen:
Frequency converter input three-phase alternating current by actual measurement and when recording feeder actual motion, and when carrying out low voltage ride-through capability test, start after tested frequency converter makes frequency converter band magnetic powder brake normally run, progressively increase magnetic powder brake exciting curent, monitoring frequency converter input three-phase alternating current simultaneously, keeping when reaching actual motion value exciting curent constant.The retarding torque that magnetic powder brake produces under this exciting curent is identical with during actual motion.
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| CN201510563179.6A CN105403776A (en) | 2015-09-07 | 2015-09-07 | Test method of low voltage ride-through capability of frequency converter based on magnetic powder brake |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105720885A (en) * | 2016-04-13 | 2016-06-29 | 上海发电设备成套设计研究院 | Method for achieving low-voltage ride through of high-voltage frequency converter |
| CN106093776A (en) * | 2016-07-25 | 2016-11-09 | 国网江西省电力科学研究院 | A kind of simulated machine load characteristic low voltage test system based on converter |
| CN107340444A (en) * | 2017-07-31 | 2017-11-10 | 国网上海市电力公司 | A kind of voltage ride-through test system and method |
| CN107422202A (en) * | 2017-06-21 | 2017-12-01 | 上海赛璞乐电力科技有限公司 | A kind of 3000kVA grades large-capacity transducer low voltage crossing pilot system |
| CN108306574A (en) * | 2018-01-30 | 2018-07-20 | 国网河南省电力公司电力科学研究院 | A kind of frequency converter safety operation area computational methods |
| CN108594034A (en) * | 2018-03-02 | 2018-09-28 | 深圳供电局有限公司 | A kind of voltage dip monitoring device and method suitable for frequency converter |
| CN112649729A (en) * | 2020-11-26 | 2021-04-13 | 天地（常州）自动化股份有限公司 | Test system and test method for comprehensively evaluating control performance of frequency converter |
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105720885A (en) * | 2016-04-13 | 2016-06-29 | 上海发电设备成套设计研究院 | Method for achieving low-voltage ride through of high-voltage frequency converter |
| CN105720885B (en) * | 2016-04-13 | 2018-07-27 | 上海发电设备成套设计研究院 | A method of realizing high-voltage frequency converter low voltage crossing |
| CN106093776A (en) * | 2016-07-25 | 2016-11-09 | 国网江西省电力科学研究院 | A kind of simulated machine load characteristic low voltage test system based on converter |
| CN106093776B (en) * | 2016-07-25 | 2023-06-16 | 国网江西省电力科学研究院 | Frequency converter-based low-voltage test system for load characteristics of analog motor |
| CN107422202A (en) * | 2017-06-21 | 2017-12-01 | 上海赛璞乐电力科技有限公司 | A kind of 3000kVA grades large-capacity transducer low voltage crossing pilot system |
| CN107340444A (en) * | 2017-07-31 | 2017-11-10 | 国网上海市电力公司 | A kind of voltage ride-through test system and method |
| CN107340444B (en) * | 2017-07-31 | 2023-08-01 | 国网上海市电力公司 | Voltage ride-through test system and method |
| CN108306574A (en) * | 2018-01-30 | 2018-07-20 | 国网河南省电力公司电力科学研究院 | A kind of frequency converter safety operation area computational methods |
| CN108594034A (en) * | 2018-03-02 | 2018-09-28 | 深圳供电局有限公司 | A kind of voltage dip monitoring device and method suitable for frequency converter |
| CN112649729A (en) * | 2020-11-26 | 2021-04-13 | 天地（常州）自动化股份有限公司 | Test system and test method for comprehensively evaluating control performance of frequency converter |
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Application publication date: 20160316 |