A kind of series compensation device and its capacity optimization method
Technical field
The present invention relates to electric and electronic technical field, and in particular to a kind of series compensation device and its capacity optimization method.
Background technology
Series compensation device is the visual plant for improving transmission system transmission capacity and improving transmission line parameter:It is long away from
The influence of inductance in transmission line of electricity can be offset by series capacitor in transmission line of electricity, so that shorten equivalent electrical distance,
The ability to transmit electricity and voltage stability of raising system;Transmission line of electricity can be increased by current-limiting reactor in heavily loaded transmission line of electricity
Equivalent reactance, so as to by power flow transfer to other transmission lines of electricity, solves the problems, such as transmission line of electricity heavy duty or even overloads.
The method referred to as fixed series compensation of line build-out is carried out by series capacitor or current-limiting reactor, it has control letter
The characteristics of list, good economy performance, but the compensation capacity of the method is unable to flexible modulation, and the mismatch of parameter may cause system to be shaken
Swing.Conventional Thyristor Controlled Seriescompensation is mainly made up of reactor, capacitor and half control switching device, it is possible to achieve seal in capacitive reactance
Control, but there is a problem of that insulating requirements are high, response speed not enough fast, cost is high.The synchronization for being constituted using full-controlled device at present
Voltage controller mainly includes THE UPFC (Unified Power Flow Controller, UPFC) and static
Synchronous series compensator (Static Synchronous Series Compensator, SSSC).
The operation principle of THE UPFC and SSSC is:
Because line current grade higher when being applied to transmission system, the series side or SSSC devices of UPFC are typically
It is linked into system by series transformer:The series side or SSSC of UPFC are equivalent to a synchronous AC power, when injection
Controllable voltage pressure drop opposite in phase or identical with line reactance, can play a part of similar series electrical perhaps inductance, specifically
For:
Fig. 1 is the relation schematic diagram of offset voltage and compensation electric current, as illustrated, when the series side or SSSC of UPFC are felt
Property compensation when, as injecting voltage amplitude increases, the increase of device equivalent reactance, circuit active power reduces therewith:Work as transverter
The injecting voltage of inductive compensation amount hour transverter is minimum Umin, and the electric current for passing through transverter is maximum Imax;When changing
The injecting voltage of transverter is maximum U when stream device inductive compensation amount is bigmax, and the electric current for passing through transverter is minimum value Imin。
To sum up need to meet the injecting voltage of transverter simultaneously when transverter capacity is designed and flow through the electric current of transverter, i.e. transverter
Maximum capacity need to meet S=UmaxImax, then cause cost to increase, it is unfavorable for construction and transformation in large scale electric network.
The content of the invention
In order to overcome the defect of prior art, the invention provides a kind of series compensation device and its capacity optimization method.
In a first aspect, the technical scheme of series compensation device is in the present invention:
Described device includes coupling transformer and transverter;
The first side winding series connection of the coupling transformer is accessed in circuit to be compensated, secondary side winding and the transverter
It is in parallel;
The first side winding and/or secondary side winding are provided with multiple taps, for changing the coupling transformer
Voltage change ratio.
The present invention further provides preferred embodiment be:
The first side winding and/or secondary side winding are provided with load ratio bridging switch;
The load ratio bridging switch, the tap is connect for being adjusted under the conditions of not powering off, and changes the coupling transformer
Voltage change ratio.
The present invention further provides preferred embodiment be:
When the tap increases specifically for the equivalent impedance when the series compensation device carries out inductive compensation,
Increase voltage change ratio;When the equivalent impedance reduces, reduce the voltage change ratio.
The present invention further provides preferred embodiment be:
The transverter is voltage source converter.
The present invention further provides preferred embodiment be:
Described device is further included:Disconnecting switch, the equipment for measuring electric current and/or voltage, and/or, for protecting
The equipment for protecting the coupling transformer and/or the transverter.
The present invention further provides preferred embodiment be:
The equipment for protecting the coupling transformer and/or the transverter specially portable protective gaps are lightning-arrest
Device.
Second aspect, the technical scheme of the capacity optimization method of series compensation device is in the present invention:
Described device includes coupling transformer and transverter;The first side winding series connection of the coupling transformer is accessed to be waited to mend
Repay in circuit, secondary side winding is in parallel with the transverter;It is respectively provided with the first side winding and/or secondary side winding many
Individual tap;
The capacity optimization method includes:
The equivalent impedance that the series compensation device is obtained when carrying out inductive compensation to the circuit to be compensated;
The voltage change ratio of the coupling transformer is adjusted according to the equivalent impedance.
The present invention further provides preferred embodiment be:
The voltage change ratio according to equivalent impedance regulation coupling transformer includes:
When the equivalent impedance increases, increase the voltage change ratio;
When the equivalent impedance reduces, reduce the voltage change ratio.
The present invention further provides preferred embodiment be:
Shown in the voltage change ratio k such as following formulas (1):
Wherein, UNet sideAnd UValve sideIt is the primary side magnitude of voltage and secondary side magnitude of voltage of the difference coupling transformer.
The present invention further provides preferred embodiment be:
Shown in the regulation principle such as following formula (2) of the voltage change ratio:
S1=S2 (2)
Wherein, S1And S2Transverter capacity before and after respectively described equiva lent impedance value changes;
Shown in transverter capacity such as following formula (3) before the equivalent impedance conversion:
S1=U1I1 (3)
Wherein, U1It is the terminal voltage of the transverter before equiva lent impedance value changes, I1To flow through institute before equiva lent impedance value changes
State the electric current of transverter;
Shown in transverter capacity such as following formula (4) after the equiva lent impedance value changes:
S2=U2I2 (4)
Wherein, U2It is the terminal voltage of the transverter after equiva lent impedance value changes, I2To flow through institute after equiva lent impedance value changes
State the electric current of transverter.
Compared with immediate prior art, the beneficial effects of the invention are as follows:
1st, a kind of series compensation device that the present invention is provided, in may be mounted at transmission line of electricity or distribution line, in perception
Compensating impedance can connect tap after changing by adjusting, and the voltage change ratio for changing coupling transformer changes the end electricity of transverter
Pressure so that the capacity of transverter remains constant before and after the inductive compensation impedance that series compensation device is exported changes;
2nd, the capacity optimization method of a kind of series compensation device that the present invention is provided, by dynamic regulation coupling transformer
Voltage change ratio, the terminal voltage maximum that can prevent transverter and the current maxima for flowing through transverter occur simultaneously, keep changing
Stream device capacity maintains steady state always, saves the capacity of transverter, and then reduce being manufactured into for series compensation device
This.
Brief description of the drawings
Fig. 1:The relation schematic diagram of offset voltage and compensation electric current;
Fig. 2:A kind of series compensation device topology schematic diagram in the present embodiment;
Fig. 3:The relation schematic diagram of the voltage change ratio of coupling transformer and inductive compensation electric current in the embodiment of the present invention;
Wherein, 11:The first system;12:Second system;13:Transmission line of electricity;21:Coupling transformer;22:Transverter.
Specific embodiment
To make the purpose, technical scheme and advantage of the embodiment of the present invention clearer, below in conjunction with the embodiment of the present invention
In accompanying drawing, the technical scheme in the embodiment of the present invention is clearly and completely illustrated, it is clear that described embodiment is
A part of embodiment of the present invention, rather than whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art
The every other embodiment obtained under the premise of creative work is not made, belongs to the scope of protection of the invention.
Below in conjunction with the accompanying drawings, a kind of series compensation device provided in an embodiment of the present invention is illustrated.
Fig. 2 is a kind of series compensation device topological structure schematic diagram in the present embodiment, as illustrated, being connected in the present embodiment
Compensation device is arranged between the first system 11 and second system 12, mainly includes coupling transformer 21 and transverter 22.Wherein,
The first side winding series connection of coupling transformer 21 is accessed in circuit 13 to be compensated, and secondary side winding is with transverter 22 simultaneously
Connection.Multiple taps, the voltage change ratio for changing coupling transformer are set in first side winding and/or secondary side winding.This
When tap increases specifically for the equivalent impedance when series compensation device carries out inductive compensation in embodiment, increase voltage
No-load voltage ratio;When the equivalent impedance reduces, reduce the voltage change ratio.Meanwhile, transverter 22 can use voltage source converter
Device.
During series compensation device may be mounted at transmission line of electricity or distribution line in the present embodiment, sent out in inductive compensation impedance
Tap can be connect by adjusting after changing, the voltage change ratio for changing coupling transformer changes the terminal voltage of transverter so that change
The capacity for flowing device remains constant before and after the inductive compensation impedance that series compensation device is exported changes.
Further, series compensation device also includes following structures in the present embodiment.
Series compensation device also includes load ratio bridging switch in the present embodiment, and the load ratio bridging switch can be arranged on once
On the winding of side, it is also possible to be arranged in secondary side winding, the tap for adjusting the tap or Secondary Winding that connect first side winding
Head, changes the voltage change ratio of coupling transformer.
By configuring load ratio bridging switch in the present embodiment, it is possible to achieve coupling transformer is not powering off the bar of normal operation
Change voltage change ratio under part, so as to ensure series compensation device reliability service, improve the stability of system.
Further, series compensation device can also include following structures in the present embodiment.
When series compensation device is applied to different transmission lines of electricity or distribution line in the present embodiment, can be according to actual line
Road connected mode increases corresponding disconnecting switch, the equipment for measuring electric current and/or voltage, and/or, for protecting the coupling
The equipment for closing transformer and/or the transverter.Wherein, it is specially for the equipment for protecting coupling transformer and/or transverter
Portable protective gaps or arrester.
Below in conjunction with the accompanying drawings, a kind of capacity optimization method of series compensation device provided in an embodiment of the present invention is said
It is bright.
Series compensation device includes coupling transformer 21 and transverter 22, wherein the one of coupling transformer 21 in the present embodiment
Secondary side windings in series is accessed in circuit to be compensated, and secondary side winding is in parallel with transverter 22.Meanwhile, capacity optimization in the present embodiment
Method is applied to the series compensation device worked under inductive compensation state, can specifically implement as steps described below.
1st, equivalent impedance when series compensation device carries out inductive compensation is obtained.
2nd, the voltage change ratio of coupling transformer is adjusted according to equivalent impedance.
In the present embodiment shown in voltage change ratio such as following formula (1):
Wherein, UNet sideAnd UValve sideIt is the primary side magnitude of voltage and secondary side magnitude of voltage of difference coupling transformer.
Fig. 3 is the relation schematic diagram of the voltage change ratio with inductive compensation electric current of coupling transformer in the embodiment of the present invention, such as
Shown in figure, the voltage change ratio of coupling transformer and the negatively correlated relation of inductive compensation electric current in the present embodiment, specially:When equivalent
Transverter both end voltage increase when impedance value increases, now adjusts voltage change ratio increase so that the terminal voltage of transverter reduces, and enters
And the transverter capacity before and after equivalent impedance can be controlled to change remains constant;Flowed through when equivalent impedance reduces and changed
The electric current increase of device is flowed, voltage change ratio is now adjusted and is reduced, reduce the electric current for flowing through transverter, and then equivalent resistance can be controlled
Transverter capacity before and after anti-value changes remains constant.
Shown in the regulation principle such as following formula (2) of the voltage change ratio that coupling transformer is adjusted in the present embodiment:
S1=S2 (2)
Wherein, S1And S2Transverter capacity respectively before and after equiva lent impedance value changes.
Shown in transverter capacity such as following formula (3) before equiva lent impedance value changes:
S1=U1I1 (3)
Wherein, U1It is the terminal voltage of transverter before equiva lent impedance value changes, I1Changed to be flowed through before equiva lent impedance value changes
Flow the electric current of device.
Shown in transverter capacity such as following formula (4) after equiva lent impedance value changes:
S2=U2I2 (4)
Wherein, U2It is the terminal voltage of transverter after equiva lent impedance value changes, I2Changed to be flowed through after equiva lent impedance value changes
Flow the electric current of device.
By the voltage change ratio of dynamic regulation coupling transformer in the present embodiment, the terminal voltage of transverter can be prevented maximum
The current maxima for being worth and flowing through transverter occurs simultaneously, keeps transverter capacity to maintain steady state always, saves and changes
The capacity of device is flowed, and then reduces the manufacturing cost of series compensation device.
Obviously, those skilled in the art can carry out various changes and modification without deviating from essence of the invention to the present invention
God and scope.So, if these modifications of the invention and modification belong to the scope of the claims in the present invention and its equivalent technologies
Within, then the present invention is also intended to comprising these changes and modification.