CN102412544A - Power-uninterrupted ice melting and SVG-type reactive static compensation compound device and use method thereof - Google Patents

Abstract

The invention discloses a power-uninterrupted ice melting and SVG-type reactive static compensation compound device and a use method thereof. The device at least comprises two sets of converters, wherein the DC (direct current) sides of the two sets of converters share a set of DC capacitors to form a back-to-back conversion system, the AC (alternating current) side of the first set of converters is connected with the low-voltage side of a first converter transformer, the AC side of the second set of converters can be respectively connected with the low-voltage side of the first converter transformer or a second converter transformer through a switch disconnecting link, the high-voltage side of the first converter transformer is connected parallel to an alternating current bus of a transformer station, the high-voltage side of the second converter transformer is connected to a line to be subjected to ice melting in series through the switch disconnecting link, and the compound device is controlled by a comprehensive controller to operate. The use method of the compound device comprises a power-uninterrupted ice melting operating state and a reactive static compensation operating state, and the stability of a system can not be destroyed.

Description

The ice-melt that the do not have a power failure SVG type reactive static plerosis of holding concurrently attaches together and puts and method for using

Technical field

The present invention relates to a kind of electric device, particularly a kind of both having can be used for, can be used for electrical network is carried out the set composite and the method for using thereof of the idle static compensation of SVG type again to the power circuit ice-melt that do not have a power failure.

Background technology

Power circuit icing problem, in different all will the taking place of the annual degree in part provinces and regions, China south, especially that rare ice damage in 2008 brings major disaster to all electrical networks of economizing in south, and long-time, large-area power-cuts influences huge to national economy and people's lives.The electrical network icing also is the major issue that countries in the world generally are concerned about.

Retrieve the de-icing technology of international and domestic power circuit, commonly used is divided into two types: the one, when the occurrence of large-area icing, after the line out of service; Adopt artificial deicing or mechanical deicing, the de-icing work amount is big, and interruption duration is long; Economic loss is serious, and mechanical deicing's method does not have maturation.Second type is thermal ice-melting, and thermal ice-melting is divided into the power failure ice-melt again and does not have a power failure two types of ice-melts.

The common method of power failure ice-melt has following two kinds:

1, ac short circuit up-flow ice-melt.Desire DC ice-melting (like 110KV or 220KV circuit) with 2～3 and be connected in series through switch operation, the terminal man-made short-circuit of tandem link, first section directly adds AC power (like 10KV or 35KV) and carries out the short circuit ice-melt.This is a most frequently used method in the ice-melt practice of all provinces in south, and its advantage is not need special equipment, and the production scene is very practical.Shortcoming is that its short circuit power source voltage is non-adjustable, will the bar number of series circuit be calculated in advance, and selected difficulty is bigger to the electrical network impact during switching power supply, also needs adjust protection definite value and protection investing method temporarily.In relevant several transformer stations, all to vacate the serial connection that a bus is used for DC ice-melting, make power system operating mode more weak.The switch operation time is long, is difficult to tackle the ice-melt requirement of many circuits when simultaneously icing taking place.This method had both consumed meritorious in short circuit up-flow process, consumed a large amount of idlely again, and the reactive power consumption amount is approximately 4 times of meritorious consumption, and is very big to the line voltage influence, so that can't use at 500KV and above circuit.

2, utilize the SVC reactive static to mend device, circuit is carried out the direct-current short circuit ice-melt as deicing device.This is after that rare ice damage in 2008, the deicing device that development puts into operation.Behind circuit generation icing, circuit is stopped transport, the line end man-made short-circuit, earlier first section two add the direct voltage of mending device rectification output through SVC type reactive static on mutually, two of circuit is carried out the direct-current short circuit ice-melt mutually, again third phase is carried out ice-melt after the end.Its advantage is that the direct voltage of device output is adjustable, can be adapted to the circuit of any length and electric pressure.Ice-melt compares that consumption systems is not idle with ac short circuit.As ice-melt equipment, at ordinary times as idle static compensation arrangement, utilization rate of equipment and installations is high during icing.Shortcoming is once can only melt two phases, and the ice-melt time is long, and it is big that switch operation and manual work are provided with the short-circuit line workload, and will have a power failure and carry out.

The method of ice-melt of not having a power failure mainly contains following two kinds:

1, Adjustment System trend strengthens the method that DC ice-melting is loaded.Through circuit of scheduling excision, load transfer to a circuit of two circuits is made its ice-melt, or make whole load currents of heavy ice line end transformer station all pass through a circuit of heavy icing area.The method reaches for the less 110kV in cross section has certain feasibility with line; For the circuit of 220kV and above electric pressure, because conductor cross-section is big, the restriction of power system capacity and operational mode in addition; And all there is the system stability problem in all electric pressure circuits; Adopt the actual effect that increases the ice-melt of icing line load method of current to still need and further study, theoretic discussion at present is more, does not have the case of practical application.

2, the beginning seventies in last century; Baoji power supply administration is on the circuit of 110KV double bundle conductor; The geometrical clamp of the double bundle conductor of the part of path that icing be prone to take place throughout the year is replaced by insulating blanked clamper, and portion builds the ice-melt station in the line, adds ice-melt circulation for every phase double bundle conductor; Concurrent thermal effect stack realizes not having a power failure ice-melt with load current, and this is the ice-melting mode that do not have a power failure of present unique use.But, all to build an ice-melt station on every circuit, equipment has high input, and utilization rate of equipment and installations is low.The circuit middle part is built at the ice-melt station in, generally is the place deep in the mountains, and is difficult in maintenance.Using object must be double bundle conductor, and limitation is big, is difficult to generally apply.

In sum, the de-icing technology under the existing not power failure mode does not have general promotional value, and the power failure de-icing technology all will carry out under the power failure mode, and manual work articulates short-circuit line and power failure operation element amount is big, and the time is long, the more important thing is the reliable power supply that influences circuit.

Summary of the invention

Defective or deficiency to above-mentioned prior art existence; In order to realize the quick practical ice-melt that do not have a power failure, and improve usage ratio of equipment, the objective of the invention is to; Providing a kind of has the ice-melt that the do not have a power failure SVG type reactive static of holding concurrently and mends the set composite (hereinafter to be referred as set composite) and the method for using thereof of two kinds of functions; Use same set of device, when icing takes place, be used for, use as the idle static compensation arrangement of SVG type under the electrical network normal operation the power circuit ice-melt that do not have a power failure.

In order to realize above-mentioned task, the present invention takes following technical solution to be achieved:

A kind of ice-melt that do not have a power failure SVG type reactive static plerosis of holding concurrently attaches together and puts; It is characterized in that; Have two groups of converters at least, the shared one group of direct current capacitor of its DC side constitutes change of current system back-to-back, and the AC side of first group of converter is connected with the first converter transformer low-pressure side; The AC side of second group of converter can be connected with the low-pressure side of first converter transformer or second converter transformer respectively through switching disconnecting link; The high-pressure side of first converter transformer is connected to the ac bus of transformer station, and the high-pressure side of second converter transformer is serially connected with on the circuit of desiring ice-melt through switching disconnecting link, and set composite is by ICU control operation.

When the first converter AC side voltage was equal with substation bus bar voltage, first converter transformer saved.

The above-mentioned ice-melt that the do not have a power failure SVG type reactive static plerosis of holding concurrently attaches together the method for using of putting, and it is characterized in that, comprises following two kinds of operating states:

A) the ice-melt operating state that do not have a power failure: the AC side of first group of converter is connected with the low-pressure side of first converter transformer; The AC side of second group of converter is connected with the low-pressure side of second converter transformer; ICU is in reactive static according to first group of converter of sine pulse midth modification (SPWM) control and mends operating state, controls second group of converter and is in the ice-melt operating state;

B) reactive static is mended operating state: the AC side of two groups of converters in the set composite; All be connected in the low-pressure side of first converter transformer; ICU is in SVG type reactive static synchronously according to two groups of converters of sine pulse midth modification (SPWM) control and mends running status, and second converter transformer is in shut down condition.

The invention has the beneficial effects as follows: in a transformer station, only be equipped with a cover set composite; Can be to the circuit of all the different electric pressures in the transformer station; Through the switch operation ice-melt that do not have a power failure successively, it is fast to cut throwing speed, and the ice-melt workload is little; Ice-melt in the time of both can having tackled part circuit generation icing, the ice-melt requirement in the time of also tackling large tracts of land generation icing.One covering device promptly can be used for the ice-melt to circuit, and as idle static compensation equipment, usage ratio of equipment is high under the electrical network normal condition.Especially SVG type reactive power compensation technology; It is existing up-to-date reactive power compensation technology; Both can send reactive power; Also can absorbing reactive power, can be from rated capacity perceptual idle to the rapid adjustment of carrying out continuously smooth the capacitive reactive power of rated capacity, become the new technology that substitutes the SVC reactive-load compensation equipment and begun popularization and application.On the basis of implementing the SVG application, add the ice-melt function, small investment, effect is big.System stability can not destroy when set composite was used for ice-melt.

Description of drawings

Fig. 1 is the key wiring diagram of set composite.HLQ1 and HLQ2 have been shared two groups of converters of one group of direct current capacitor, converter circuit of forming by the full control of GTO, IGBT, IGCT etc. in prior art power electronic device and reactor DK1, DK2, change of current resistance R 1 and R2 and filter LB composition.B1 and B2 are converter transformer, and K is for switching disconnecting link, and K1, K2, K3 are isolation switch, and MO is the bus of transformer station, and L is a circuit of transformer station, and DL is a line switching, and 1DL is the control switch of set composite.

Fig. 2 is the theory diagram of ICU in the set composite.

Fig. 3 is equivalent circuit diagram and the phasor diagram of set composite under the ice-melt operating state.

Fig. 4 is the access sketch map of set composite when in electric power system, being used for ice-melt.M1, M2, M0 represent three buses of first transformer station respectively among the figure; M3 and M4 represent the bus of second and the 3rd transformer station respectively; L1, L2, L3, L4 represent 4 circuits respectively; HLQ1, HLQ2 have been shared two groups of converters of one group of direct current capacitor, B1, B2 are converter transformer.

Below in conjunction with accompanying drawing and embodiment the present invention is done further detailed description.

Embodiment

Fig. 1 has described the ice-melt that the do not have a power failure SVG type reactive static plerosis of holding concurrently and has attached together the principle wiring of putting (hereinafter to be referred as set composite); The shared one group of direct current capacitor of DC side of two groups of converter HLQ1, HLQ2; The AC side of the 1st group of converter HLQ1 and the first converter transformer B1 are electrically connected on the bus M0 of transformer station, and the AC side of the 2nd group of converter HLQ2 is electrically connected with diverter switch K.When K is in position 1; Two groups of converter parallel runnings are in the low-pressure side of the first converter transformer B1; This moment, ICU ran on the idle static compensation work state of SVG type (SVG type reactive static benefit technology is prior art, so no longer detail) simultaneously according to two groups of converters of sine pulse midth modification of the prior art (SPWM) control.When K is in position 2; The second converter HLQ2 is connected in the low-pressure side of transformer B2; Through switch operation, break off K1, connect K2 and K3 the high-pressure side of the second converter transformer B2 is serially connected with the outlet of circuit L, ICU makes the 1st group of converter HLQ1 still work in the idle static compensation work state of SVG type; Make the 2nd group of converter HLQ2 be in the inversion operating state, set up a voltage source to the high-pressure side of the second converter transformer B2 and be serially connected with on the circuit with the line voltage distribution same frequency.The foundation in the second converter transformer B2 high side voltage source makes line current reach the ice-melt operating current to improve the meritorious and idle transmittability of circuit, and set composite is in the ice-melt operating state.

When carrying out the ice-melt operation, the high-pressure side of the second converter transformer B2 in the set composite must be serially connected with on the circuit in parallel circuit or the loop network.For not constituting the single supply circuit that looped network connects, can only improve the idle transmission of circuit on a small quantity and improve the voltage of load side, can not improve line current and reach ice melting current, so can't realize ice-melt the single supply circuit.

Fig. 2 is the ICU theory diagram in the set composite, is made up of measuring unit, control unit, signal output unit, protected location, demonstration and instruction input unit etc.Parameters such as the direct voltage of the busbar voltage of measuring unit collection transformer station, the electric current of DC ice-melting, set composite, output current.Control unit makes two groups of converters of output unit output Different control signal controlling work in reactive static and mends operating state or ice-melt operating state according to control command.Protected location set composite is protected and with the protection system coordinate operation of transformer station.Show and the instruction input unit shows the operating state and the relevant parameter of set composite, and artificial input control order.ICU may command set composite works in SVG type reactive static and mends operating state or ice-melt operating state, and the control method of two kinds of operating states is all used the work of existing sine pulse midth modification (SPWM) control converter.Different is that controlled target is different; When reactive static is mended operating state; ICU makes two groups of converters all according to the busbar voltage of transformer station height, or absorbs certain idlely or send certain reactive power, its objective is that to keep substation bus bar voltage steady; When the ice-melt operating state; ICU is controlled first group of converter and is worked in reactive static benefit state; This moment first converter the major control target be keep two groups of converters the terminal voltage of shared direct current capacitor constant; Make second group of converter to one of second group of converter B2 output and the circuit same frequency, variable alternating voltage; To change the outlet voltage of DC ice-melting, the balanced transmission that strengthens the meritorious and reactive power of circuit makes line current rise to ice melting current and is control purpose (ice melting current is all greater than the normal duty electric current).ICU can use existing techniques in realizing, and the present invention is not as the emphasis narrating content.

Fig. 3 is that set composite works on the circuit in the parallel circuit, and equivalent circuit diagram when being in the ice-melt operating state and vectogram are described in detail the ice-melt operation principle of set composite below in conjunction with Fig. 3.

Among Fig. 3, the impedance that two side systems are respectively and

DC ice-melting is X.The second converter transformer B2 high-pressure side injecting voltage is with phasor expression, and it can move arbitrarily in the disk that with

is end points.The power of being held that can get system according to Fig. 3 (a) is:

And the second converter transformer B2 high-pressure side is held power to be when not sealing in circuit:

When the second converter transformer B2 high-pressure side seals in circuit, suppose transmission system send the end and be respectively by the voltage of the terminal voltage and the second converter transformer B2 high-pressure side injected system:

The power that transmission system when

can obtain the second converter transformer B2 high-pressure side and seal in circuit is held is:

$P=\frac{U^2}{X}\sin \mathrm{\δ}+\frac{{\mathrm{UU}}_c}{X}\sin (\mathrm{\δ}+\mathrm{\ρ})$

$Q_r=\frac{U^2}{X}(1-\cos \mathrm{\δ})-\frac{{\mathrm{UU}}_c}{X}\cos (\mathrm{\δ}+\mathrm{\ρ})$

Equally, the power of being held in the time of can obtaining the second converter transformer B2 high-pressure side and do not seal in circuit is:

$P_0=\frac{U^2}{X}\sin \mathrm{\δ}$

$Q_{0r}=\frac{U^2}{X}(1-\cos \mathrm{\δ})$

The power that can obtain the set composite transmission from top formula does

$P_c=\frac{{\mathrm{UU}}_c}{X}\sin (\mathrm{\δ}+\mathrm{\ρ})$

$Q_c=-\frac{{\mathrm{UU}}_c}{X}\cos (\mathrm{\δ}+\mathrm{\ρ})$

Can see the power P of set composite transmission _cAnd Q _cOnly with

With

Analog value and ρ relevant, and irrelevant with the phase angle difference of system both sides voltage.The high-pressure side winding that is equivalent to the second converter transformer B2 has injected the adjustable voltage

of an amplitude and phase angle on the line through regulated, variation that promptly can the control circuit trend.

The ice-melt operating state of set composite: be exactly through regulating on high-tension side voltage of the second converter transformer B2 and phase place, change the meritorious transmission with load or burden without work of circuit, so that line current reaches ice melting current.And promoting the process that line current arrives the ice-melt operating current, is to realize through the mode that changes line outlet voltage, and the stable of circuit can not destroyed.

Fig. 4 adopts the application sketch map of set composite of the present invention in the transformer station of a double bus scheme.330KVM1,330KV M2 and 35KV M0 are three buses in first transformer station among the figure, and M1 and M2 are double bus scheme.M3 and M4 represent the bus of second and the 3rd transformer station respectively.Be connected with L2 by two parallel circuit L1 between first and second transformer station, circuit L3 and L4 are linked to be looped network with three transformer stations.The control switch 1DL of set composite runs on the bus of 35KV of first transformer station; When diverter switch K runs on position 1; Two groups of converter (HLQ1; HLQ2) all parallel running is in the first converter transformer B1 low-pressure side, and package unit works in reactive static and mends operating state, and the second converter transformer B2 is at shut down condition.When desire is carried out the ice-melt operation to a circuit (like L1); Only let circuit L1 run on the 330KV M1; Make other circuit (like L2 and L3) all run on M2, the bus connection switch DL0 that closes, the both sides disconnecting link of the high pressure lavatory winding of the second converter transformer B2 that closes makes second converter transformer B2 bridge joint M1 and the M2; This moment M1 and M2 equipotential, the high-pressure side of B2 does not have electric current and flows through.Diverter switch K in the set composite is run on position 2; Control the output of the second converter transformer B2 through ICU; The power that flows through the second converter transformer B2 high pressure winding is equated with circuit L1, and the electric current that flows through bus connection switch DLO this moment will be zero, break off bus connection switch DL0; The output of controlling the second converter transformer B2 again makes the electric current of circuit L1 reach ice melting current with the through-put power that strengthens circuit L1, gets into the ice-melt operating state.After ice-melt finishes; When the output of controlling the second converter transformer B2 makes circuit L1 through-put power be reduced to its normal transmission power; Flowing through the on high-tension side electric current of B2 this moment is zero; The bar coupler DL0 that closes cuts the on high-tension side both sides of second converter transformer B2 disconnecting link then, and set composite is out of service.In like manner can be successively to the three-line ice-melt that do not have a power failure respectively.

Fig. 4 is a kind of application form of set composite in transformer station's wiring of double-bus.Also can be used, when indivedual bus modes of connection cooperate with set composite is bad, also can adopt the method that installs special ice-melt bus additional according to different transformer station's wiring types.

What provide among Fig. 4 is single line schematic diagram, and the second converter transformer B2 low-pressure side winding is triangle wiring both, and yet star-like connection is not drawn among the figure.

The control switch 1DL of set composite can design it and run on 35KV or the 330KV bus.General idle static compensation equipment should run in the low-voltage distribution network, so adopted the scheme that connects on the 35KV bus in the present embodiment.In addition, when the voltage of low-voltage bus bar and converter AC side was identical, the first converter transformer B1 can save.

Claims (4)

1. the ice-melt that the do not have a power failure SVG type reactive static plerosis of holding concurrently attaches together and puts; It is characterized in that; Have two groups of converter (HLQ1 at least; HLQ2), the shared one group of direct current capacitor of its DC side constitutes change of current system back-to-back, and the AC side of first group of converter (HLQ1) is connected with first converter transformer (B1) low-pressure side; The AC side of second group of converter (HLQ2) can be connected with the low-pressure side of first converter transformer (B1) or second converter transformer (B2) respectively through switching disconnecting link (K); The high-pressure side of first converter transformer (B1) is connected to the ac bus of transformer station, and the high-pressure side of second converter transformer (B2) is serially connected with on the circuit of desiring ice-melt through switching disconnecting link, and set composite is by ICU control operation.

2. the SVG type reactive static plerosis of holding concurrently of the ice-melt that do not have a power failure described in claim 1 attaches together and puts, and it is characterized in that when first converter (HLQ1) AC side voltage equated with substation bus bar voltage, first converter transformer (B1) saved.

3. the described ice-melt that do not have a power failure of the claim 1 SVG type reactive static plerosis of holding concurrently attaches together the method for using of putting, and it is characterized in that, comprises following two kinds of operating states:

A) the ice-melt operating state that do not have a power failure: the AC side of first group of converter (HLQ1) is connected with the low-pressure side of first converter transformer (B1); The AC side of second group of converter (HLQ2) is connected with the low-pressure side of second converter transformer (B2); ICU is controlled first group of converter (HLQ1) according to the SPWM control technology and is in reactive static benefit running status, controls second group of converter (HLQ2) and is in the ice melting operation state;

B) reactive static is mended operating state: two groups of converter (HLQ1 in the set composite; HLQ2) AC side; All be connected in the low-pressure side of first converter transformer (B1); ICU is controlled two groups of converters according to the SPWM control technology, and (HLQ1 HLQ2) is in SVG type reactive static synchronously and mends running status, and second converter transformer (B2) is in shut down condition.

4. method as claimed in claim 3; It is characterized in that; The described ice-melt operating state that do not have a power failure; The high-pressure side of second converter transformer (B2) in the set composite is serially connected with on the circuit in parallel circuit or the looped network circuit, and for not constituting the single line that looped network connects, set composite can not be realized the ice-melt operation.

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