CN104795840A - System and method for improving low voltage ride through capability of wind power generation system - Google Patents

System and method for improving low voltage ride through capability of wind power generation system Download PDF

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Publication number
CN104795840A
CN104795840A CN201510203216.2A CN201510203216A CN104795840A CN 104795840 A CN104795840 A CN 104795840A CN 201510203216 A CN201510203216 A CN 201510203216A CN 104795840 A CN104795840 A CN 104795840A
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CN
China
Prior art keywords
wind generator
voltage
reactor
capability
control circuit
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Application number
CN201510203216.2A
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Chinese (zh)
Inventor
陈应纪
姜吉平
程法民
司君诚
李文杰
田野
西文藻
伦晓娟
王同晓
Original Assignee
国家电网公司
国网山东省电力公司东营供电公司
山东大学
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Application filed by 国家电网公司, 国网山东省电力公司东营供电公司, 山东大学 filed Critical 国家电网公司
Priority to CN201510203216.2A priority Critical patent/CN104795840A/en
Publication of CN104795840A publication Critical patent/CN104795840A/en

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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/70Wind energy
    • Y02E10/76Power conversion electric or electronic aspects

Abstract

The invention discloses a system and a method for improving low voltage ride through capability of a wind power generation system. The system comprises an electric reactor, the electric reactor is connected to a connection line of a grid connection bus of the wind power generation system and an electric system main electric network in series and is connected with a circuit breaker QF in parallel, the circuit breaker QF is controlled by a control circuit, and the control circuit acquires voltage values of the grid connection bus through a voltage transformer. The method includes that when the wind power generation system and the electric system main electric network work normally, the circuit breaker QF is closed; when a voltage value U3 of the grid connection bus is identical to a normal nominal voltage value Un, the control circuit does not send commands; when the voltage value U3 of the grid connection bus is lower than 0.8*Un, the control circuit sends a tripping command, and the circuit breaker QF is tripped off; when the voltage value U3 of the grid connection bus is higher than 0.8*Un, the control circuit sends a closing command, and the circuit breaker QF is closed. The system and the method have the advantages that addition of new control targets and circuits to a control system of a double-fed wind power generator is not needed, the low voltage ride through capability of the wind power generation system is improved, and the method is simple and reliable.

Description

A kind of system and method improving wind generator system low voltage ride-through capability
Technical field
The present invention relates to wind power generation field, particularly relate to a kind of system and method improving wind generator system low voltage ride-through capability.
Background technology
Wind power generation is clean energy resource, and in recent years, wind generator system is rapidly developed.Low voltage crossing, refer to when the grid-connected point voltage of wind-driven generator falls, wind-driven generator can keep low voltage crossing grid-connected, even provide certain reactive power to electrical network, support power system restoration, until power system restoration is normal, thus " passing through " this low-voltage time (region).Low voltage crossing still keeps the grid-connected specific operation function requirement of one when Voltage Drop appears in electrical network to grid-connected blower fan.Require that wind generator system has stronger low voltage crossing (LVRT) ability.CN103078349A, proposes various double-fed wind power generator system and low-voltage ride-through method etc. patent, these methods, is all to improve the control system of wind-driven generator self.Because the control system of wind-driven generator self will realize various control target, numerous target is difficult to realize in a set of control system harmonious, and control characteristic is difficult to realize optimizing.
Summary of the invention
Object of the present invention is exactly to solve the problem, propose a kind of system and method improving wind generator system low voltage ride-through capability, at and site the connect reactor of wind generator system with electric power system major network, do not need to increase new control objectives and circuit to double-fed wind power generator own control systems, improve the ability of wind generator system low voltage crossing, method is simple, reliable.
To achieve these goals, the present invention adopts following technical scheme:
A kind of system improving wind generator system low voltage ride-through capability, comprise reactor, one end of described reactor connects the output of wind generator system, the other end is by connecting the main electrical network of grid-connected bus access electric power system, described reactor is parallel with circuit breaker Q F, the controlled control circui of circuit breaker Q F, the output of described circuit breaker connection control circuit, the input of described control circuit connects the secondary side of voltage transformer, a grid-connected bus of side joint of described voltage transformer, control circuit obtains the magnitude of voltage of grid-connected bus by voltage transformer.
The reactance value Z2 of described reactor meets: Z1≤Z2 < 2Z1, wherein Z1 is the equivalent internal impedance value of wind generator system.
The equivalent internal impedance value Z1 of described wind generator system gets equivalent internal impedance value when wind generator system 1/3 wind-driven generator runs.
Improve a method for wind generator system low voltage ride-through capability, it is characterized in that, when wind generator system and the main electrical network of electric power system normally run, circuit breaker Q F closes;
When the magnitude of voltage U3 of grid-connected bus is normal rating voltage U n, control circuit does not send instructions;
During lower than load voltage value Un 0.5 times of the magnitude of voltage U3 of grid-connected bus, trip command sent out by control circuit, circuit breaker Q F tripping, and reactor puts into operation;
When the magnitude of voltage U3 of grid-connected bus is greater than 0.8*Un, close command sent out by control circuit, and circuit breaker Q F closes, and reactor does not work.
The reactance value Z2 of described reactor meets: Z1≤Z2 < 2Z1, wherein Z1 is the equivalent internal impedance value of wind generator system.
The equivalent internal impedance value Z1 of described wind generator system gets equivalent internal impedance value when wind generator system 1/3 wind-driven generator runs.
The invention has the beneficial effects as follows:
The present invention does not need to increase new control objectives and circuit to double-fed wind power generator own control systems, at and site the connect reactor of wind generator system with electric power system major network, improve the ability of wind generator system low voltage crossing, method is simple, reliable.
Accompanying drawing explanation
Fig. 1 represents structural representation of the present invention;
Wherein, 1. wind generator system, the 2. main electrical network of electric power system, 3. grid-connected bus, 4. reactor, 5. voltage transformer, 6. control circuit.
Embodiment:
Below in conjunction with accompanying drawing and embodiment, the present invention will be further described:
As shown in Figure 1, wind generator system 1 is grid-connected at grid-connected bus 3 place with the main electrical network of electric power system 2, wind generator system 1 is connected with grid-connected bus connecting line a reactor 4, a reactor 4 circuit breaker Q F in parallel, the controlled circuit 6 of circuit breaker Q F controls, and control circuit 6 obtains the magnitude of voltage of grid-connected bus 3 by voltage transformer 5.
When wind generator system 1 and the main electrical network 2 of electric power system normally run, circuit breaker Q F closes, and reactor 4 is effect not.When the magnitude of voltage U3 of grid-connected bus 3 is normal rating voltage U n, control circuit 6 does not send instructions.
The main electrical network 2 of electric power system is short-circuited fault, and the magnitude of voltage U3 of grid-connected bus 3 declines.During lower than load voltage value 0.5 times of control circuit 6 measures grid-connected bus 3 magnitude of voltage U3 by voltage transformer 5, control circuit 6 trip command, circuit breaker Q F tripping, reactor 4 puts into operation.
When the main electrical network 2 of electric power system is short-circuited fault, the magnitude of voltage U3 of grid-connected bus 3 declines.Wind generator system 1 provides short circuit current by connecting line to the main electrical network 2 of electric power system.If connecting line does not have series reactor 4, the voltage of wind generator system 1 is very low, and wind-driven generator has larger short circuit current to flow through, and wind-driven generator low voltage crossing is declined, and wind-driven generator likely trips, and departs from electrical network.
When the main electrical network 2 of electric power system is short-circuited fault, the magnitude of voltage U3 of grid-connected bus 3 declines.A reactor 4 if connecting line is connected, can limit wind-driven generator short circuit current, and the voltage of wind generator system 1 can be controlled in more than 0.5 times of load voltage value, and wind-driven generator can not trip, and can not depart from electrical network.Improve the ability of wind generator system low voltage crossing.
The short trouble occurred when electric power system main electrical network 2 is cut, and when the magnitude of voltage U3 of bus is greater than 0.8*Un, close command sent out by control circuit, and circuit breaker Q F closes.Wind generator system 1 and the main electrical network of electric power system 2 recover normal operation.
In order to ensure worst electric power system main electrical network 2 short trouble, the voltage of wind generator system 1 all ensures to control more than 0.5 times at load voltage value, and the reactance value Z2 of reactor 4 should be equal to or greater than the equivalent internal impedance value Z1 of wind generator system 1.During in order to ensure electric power system main electrical network 2 short trouble, when reactor 4 is series at connecting line, wind generator system 1 and the main electrical network 2 of electric power system have and contact more closely, and the reactance value of reactor 4 should be less than the equivalent internal impedance value 2 times of wind generator system 1, is namely less than 2*Z1.
Equivalent internal impedance value Z1 due to wind generator system 1 runs the change of quantity along with wind-driven generator in wind generator system 1 and changes, in theory, the equivalent internal impedance value Z1 of wind generator system 1 should get the equivalent internal impedance value under wind generator system 1 minimum operational mode.If only have a typhoon power generator to run under wind generator system 1 minimum operational mode, resistance value Z1 may be very large.Resistance value Z1 is by this value, and a kind of method improving wind generator system low voltage ride-through capability, at most of time, can not play optimum efficiency.When wind-driven generator operation quantity is less than 1/3, the short trouble that the main electrical network 2 of electric power system occurs, the impact of the ability of wind generator system low voltage crossing is less.So in order at most of time, a kind of method improving wind generator system low voltage ride-through capability can play optimum efficiency, in fact, resistance value Z1 gets equivalent internal impedance value when wind generator system 1/3 wind-driven generator runs.
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, those skilled in the art do not need to pay various amendment or distortion that creative work can make still within protection scope of the present invention.

Claims (6)

1. one kind is improved the system of wind generator system low voltage ride-through capability, it is characterized in that, comprise reactor, one end of described reactor connects the output of wind generator system, the other end is by connecting the main electrical network of grid-connected bus access electric power system, described reactor is parallel with circuit breaker Q F, the controlled control circui of circuit breaker Q F, the output of described circuit breaker connection control circuit, the input of described control circuit connects the secondary side of voltage transformer, a grid-connected bus of side joint of described voltage transformer, control circuit obtains the magnitude of voltage of grid-connected bus by voltage transformer.
2. a kind of system improving wind generator system low voltage ride-through capability as claimed in claim 1, is characterized in that, the reactance value Z2 of described reactor meets: Z1≤Z2 < 2Z1, wherein Z1 is the equivalent internal impedance value of wind generator system.
3. a kind of system improving wind generator system low voltage ride-through capability as claimed in claim 2, is characterized in that, the equivalent internal impedance value Z1 of described wind generator system gets equivalent internal impedance value when wind generator system 1/3 wind-driven generator runs.
4. based on the method improving wind generator system low voltage ride-through capability system as claimed in claim 1, it is characterized in that, when wind generator system and the main electrical network of electric power system normally run, circuit breaker Q F closes, and reactor does not work;
When the magnitude of voltage U3 of grid-connected bus is normal rating voltage U n, control circuit does not send instructions;
During lower than load voltage value Un 0.5 times of the magnitude of voltage U3 of grid-connected bus, trip command sent out by control circuit, circuit breaker Q F tripping, and reactor puts into operation;
When the magnitude of voltage U3 of grid-connected bus is greater than 0.8*Un, close command sent out by control circuit, and circuit breaker Q F closes, and reactor does not work.
5. a kind of method improving wind generator system low voltage ride-through capability as claimed in claim 4, is characterized in that, the reactance value Z2 of described reactor meets: Z1≤Z2 < 2Z1, wherein Z1 is the equivalent internal impedance value of wind generator system.
6. a kind of method improving wind generator system low voltage ride-through capability as claimed in claim 5, is characterized in that, the equivalent internal impedance value Z1 of described wind generator system gets equivalent internal impedance value when wind generator system 1/3 wind-driven generator runs.
CN201510203216.2A 2015-04-24 2015-04-24 System and method for improving low voltage ride through capability of wind power generation system CN104795840A (en)

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Application Number Priority Date Filing Date Title
CN201510203216.2A CN104795840A (en) 2015-04-24 2015-04-24 System and method for improving low voltage ride through capability of wind power generation system

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014110658A (en) * 2012-11-30 2014-06-12 Mitsubishi Heavy Ind Ltd Wind turbine and control method for the same, and wind turbine power generation system
CN104022529A (en) * 2014-06-16 2014-09-03 张建华 Doubly-fed wind generator low voltage ride through control method based on improved Crowbar
CN104283212A (en) * 2014-10-11 2015-01-14 广西大学 Double-fed wind power generation set physical simulation platform based on Compact RIO

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014110658A (en) * 2012-11-30 2014-06-12 Mitsubishi Heavy Ind Ltd Wind turbine and control method for the same, and wind turbine power generation system
CN104022529A (en) * 2014-06-16 2014-09-03 张建华 Doubly-fed wind generator low voltage ride through control method based on improved Crowbar
CN104283212A (en) * 2014-10-11 2015-01-14 广西大学 Double-fed wind power generation set physical simulation platform based on Compact RIO

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Application publication date: 20150722