CN106130055A - The lever variable-power control system of HVDC transmission system and method thereof - Google Patents

Abstract

The present invention provides a kind of control system and the method for HVDC transmission system for being transmitted to the second AC network by power from the first AC network.This system includes voltage measurement parts and controller.Voltage measurement parts measure the first alternating voltage of described first AC network.Controller includes: computing module, calculates the difference between the first ac voltage measurement value and the first alternating voltage reference value；Rectifier inverter control module, regulates the DC voltage value of the rectifier inverter of described HVDC transmission system to regulate reactive power that described rectifier inverter absorbs/send and then reducing the difference between described first ac voltage measurement value and the first alternating voltage reference value based on described difference；Inverter control module, DC voltage value based on the rectifier inverter after regulation regulates the DC current values of described HVDC transmission system to keep the active power transmitted through described aerial line HVDC transmission system after the adjustment constant.

Description

The lever variable-power control system of HVDC transmission system and method thereof

Technical field

The present invention relates to the control system by HVDC transmission system through-put power between AC network and method, More particularly, it relates to the rectifier inverter of HVDC transmission system and the control system of inverter and method.

Background technology

Due to environment, increasing electric power from regenerative resource, such as wind energy.And in some countries, extremely Known to some, extensive Renewable Energy Resources distance power load is the remotest less.Therefore, Large Copacity becomes with long-distance transmissions For the outstanding feature of the Renewable Energy Development of these countries, such as, China and the U.S. etc..

For Large Copacity long distance power transmission, conventional high-tension HVDC Transmission Technology is one the most attractive transmission of electricity skill Art..This technology have employed line commutation inverter based on IGCT (line commutated converter, LCC) technology Complete the power conversion of AC-DC/DC-AC.Owing to IGCT can work under high current grade continuously, this This technology is made to be suitable to high capacity transmission, such as, the power transmission of more than 8GW.Compare with the ac transmission of equivalent capability, due to Transmission losses is little, and straight-flow system is more suitable for long distance power transmission.Therefore, to be suitable to above-mentioned Large Copacity remote for conventional high-tension DC techniques Wind-powered electricity generation transmission.One conventional high-tension straight-flow system mainly (is used for the friendship of AC network (the first AC network) by inverter Stream electricity is transformed to galvanic rectifier inverter and the inverter that DC power conversion is alternating current that will be transmitted), transmission The transformed galvanic aerial line obtained and or cable, converter power transformer, and wave filter, capacitor, the group such as reactor Become..Inverter and the second AC network connect, and the latter consumes the AC power from inverter output.

Large-scale wind power for non-islet operation transmits, and can use the D.C. high voltage transmission skill of the LCC of variable power control Art scheme, the wind power instantaneous value that i.e. DC electric power dynamic tracking is sent.HVDC by the LCC of variable power control Technology of transmission of electricity scheme is applied when fluctuating power transmits, so that the ac grid voltage connecting fluctuation power supply can be maintained at In the range of operation allowed, need to connect/disconnect alternating current filter and/or shnt capacitor continually, regulate transformation continually Device tap changer reduces the change of the reactive power caused by the fluctuation of active power.This will increase system maintenance cost and The reliability of reduction system.

Summary of the invention

According to an aspect of the present invention, it is provided that a kind of for power is passed to the second AC network from the first AC network The control system of defeated HVDC transmission system, including voltage measurement parts and controller.Voltage measurement parts are used for measuring First alternating voltage of described first AC network.Controller includes: computing module, for calculating the first ac voltage measurement value And the difference between the first alternating voltage reference value；Rectifier inverter control module, for regulating described height based on described difference The DC voltage value of the rectifier inverter of pressure DC transmission system is to regulate the idle merit that described rectifier inverter absorbs/sends Rate and then reduce the difference between described first ac voltage measurement value and the first alternating voltage reference value；With inverter control Molding block, regulates the unidirectional current of described HVDC transmission system for DC voltage value based on the rectifier inverter after regulation Flow valuve is to keep the active power transmitted through described aerial line HVDC transmission system after the adjustment constant.

According to another aspect of the present invention, it is provided that a kind of for by power from the first AC network to the second AC network The control method of the HVDC transmission system of transmission, including: measure the first alternating voltage of described first AC network；Calculate Difference between first ac voltage measurement value and the first alternating voltage reference value；Described HVDC is regulated based on described difference The DC voltage value of the rectifier inverter of transmission system so as to regulate reactive power that described rectifier inverter absorbs/send and then Reduce the difference between described first ac voltage measurement value and the first alternating voltage reference value；And based on the rectification after regulation The DC voltage value of inverter regulates the DC current values of described HVDC transmission system to keep after the adjustment The active power transmitted through the aerial line of described HVDC transmission system is constant.

Based on technique scheme, can reduce between the first ac voltage measurement value and the first alternating voltage reference value Difference.Thus reduce the power sent due to the power generating equipment of such as new forms of energy, there is fluctuation to be brought within a period of time The instability of alternating voltage.This reduce undulatory property power supply, such as new forms of energy, the interference that grid stability is brought, improve The stability of the electrical network containing undulatory property power supply and reliability.

Preferably, if the first ac voltage measurement value calculated by described computing module and the first alternating voltage reference Difference between value is just, then increase by the first AC network to described rectification by the angle of ignition of the described rectifier inverter of increase The reactive power transmission of inverter；And if the first ac voltage measurement value calculated by described computing module with first hand over Difference between stream voltage reference value is negative, then reduce the first AC network by the angle of ignition of the described rectifier inverter of reduction Transmit to the reactive power of described rectifier inverter.Wherein it is possible to come by increasing/reduce the angle of ignition of described rectifier inverter Turn down/heighten the DC voltage value of described rectifier inverter, can come by increasing/reduce the flame-out angle of described inverter Heighten/turn down the DC current values of described inverter, so that by high-voltage direct current from the first AC network to the The active power of two AC network transmission keeps constant, but the reactive power exchange between the first AC network and high-voltage direct current Adjustable.

Accompanying drawing explanation

Fig. 1 illustrate according to an embodiment of the invention for by power from the first AC network to the second AC network The control system of the HVDC transmission system of transmission；

Fig. 2 illustrate the computing module of controller according to an embodiment of the invention, inverter control module and Rectifier inverter control module；With

Fig. 3 illustrates the computing module of controller according to another embodiment of the invention, inverter control module With rectifier inverter control module.

Detailed description of the invention

Fig. 1 illustrate according to an embodiment of the invention for by power from the first AC network to the second AC network The control system of the HVDC transmission system of transmission.

As it is shown in figure 1, control system 1 includes voltage measurement parts 10 and controller 11.Voltage measurement parts 10 are used for surveying First alternating voltage U of flow control one AC network_{AC_1a,}U_{AC_1b,}U_{AC_1c}.Voltage measurement parts 10 can use potential difference meter, its Electromagnetic principles is used to measure voltage.Voltage measurement parts 10 can measure the three-phase voltage of the first AC network, U* respectively_{AC_1a,} U*_{AC_1b,}U*_{AC_1c}。

Controller 11 can use a piece of or central processing unit of several large scale integrated circuit compositions, or by microcomputer The integrated one-chip microcomputer on a single die of major part of calculation machine.Functionally, controller 11 may include that meter Calculate module 110, inverter control module 111 and rectifier inverter control module 112.In HVDC transmission system, Inverter control module 111 can as determining current terminal to regulate the DC current values of described HVDC transmission system, And rectifier inverter control module 112 can be as determining voltage end to regulate the rectifier inverter of described HVDC transmission system DC voltage value.In order to realize above-mentioned regulation, such as inverter control module 111 can control the crystalline substance of inverter The flame-out angle of brake tube, and rectifier inverter control module 112 can control the angle of ignition of IGCT of rectifier inverter.In order to carry High first ac voltage measurement value U*_{AC_1a,}U*_{AC_1b,}U*_{AC_1c}Real-time reduce the measurement signal of voltage measurement parts 10 and control Signal transmission delay between device 11 processed, voltage measurement parts 10 and controller 11 may be arranged in rectification current conversion station.

As it is shown in figure 1, the inverter control module 111 of controller 11 and rectifier inverter control module 112 are respectively Associate with inverter and rectifier inverter, and the three-phase electricity that inverter control module 111 is to the first AC network Pressure measured value U*_{AC_1a,}U*_{AC_1b,}U*_{AC_1c}Respond.Additionally, inverter control module 111 and rectifier inverter control There is signal between module 112 to connect, thus rectifier inverter control module 112 can be to inverter control module 111 Output signal respond.

Fig. 2 illustrate the computing module of controller according to an embodiment of the invention, inverter control module and Rectifier inverter control module.As in figure 2 it is shown, be the instantaneous value of every phase as the first ac voltage measurement value controlling target U*_{AC_1a,}U*_{AC_1b,}U*_{AC_1c}.Need to calculate the root-mean-square value of every phase with formula (1a).Three-phase is calculated again mean square with formula (1b) Root.With the first alternating voltage reference value V_{AC_1a,}V_{AC_1b,}V_{AC_1c}Between difference export from the comparator of computing module 110.Example As, this difference can be expressed to use the root mean square form of three-phase:

$U_{Arms}=\sqrt{\frac{x_1^2+x_2^2+x_3^2+...+x_n^2}{N}}---\left(1a\right)$

$\left\{\begin{array}{c}{U}_{rms}=\frac{\sqrt{U_{AB}^2+U_{BC}^2+U_{CA}^2}}{3}\\ U_{AB}=U_{Arms}-U_{Brms}\\ U_{BC}=U_{Brms}-U_{Crms}\\ U_{CA}=U_{Crms}-U_{Arms}\end{array}\right.---\left(1b\right)$

Wherein, Urms is three-phase root-mean-square value, U_ArmsIt is the root-mean-square value of A cross streams voltage, U_BrmsIt is B cross streams voltage Root-mean-square value, U_CrmsIt it is the root-mean-square value of C cross streams voltage.Sampled point number in one cycle when N is to measure.x_nIt is each Measurement magnitude of voltage corresponding to sampled point.

Preferably, the output of this comparator is applied to the proportional and integral controller PI of computing module 110, and from calculating The signal of the proportional and integral controller output of module 110 is applied to inverter control module 111.From computing module 110 The signal of proportional and integral controller output can be transmitted to inverter control module by telecommunication.

Basic law according to HVDC transmission system:

$I_{DC}=\frac{U_{DCR}-U_{DCI}}{Z}---\left(2\right)$

Wherein, I_DCRepresent that HVDC transmission system flows through the DC current of aerial line, U_DCRRepresent the straight of rectifier inverter Stream voltage, U_DCIRepresenting the DC voltage of inverter, Z represents the impedance of the aerial line of HVDC transmission system.

As described above, the impedance Z of the aerial line of the HVDC transmission system in equation (2) is steady state value, inverse The controlled DC current I being made as determining the inverter/converter of current terminal of transform stream device control module 111_DC, rectifier inverter simultaneously The controlled DC voltage U being made as determining the rectification current transformer of voltage end of control module 110_DCR.Additionally, the direct current of inverter Voltage U_DCIFollow the DC voltage U of rectification current transformer_DCRChange and change.

Theory according to HVDC transmission system: (such as can be changed with external equipment by regulation AC network Stream device) between reactive power exchange affect and then control the ac voltage of AC network.Specifically, can be by increasing Add AC network and transmit the ac voltage reducing AC network to the reactive power of inverter, otherwise can be handed over by reduction Stream electrical network transmits the ac voltage improving AC network to the reactive power of inverter.Based on upper theory, if by calculating The first ac voltage measurement value U* that module 110 is calculated_{AC_1a,}U*_{AC_1b,}U*_{AC_1c}With the first alternating voltage reference value V_{AC_1a,} V_{AC_1b,}V_{AC_1c}Between difference be just, then increase reactive power from the first AC network to described rectifier inverter transmit, and If the first ac voltage measurement value U* calculated by computing module 110_{AC_1a,}U*_{AC_1b,}U*_{AC_1c}With the first alternating voltage ginseng Examine value V_{AC_1a,}V_{AC_1b,}V_{AC_1c}Between difference be negative, then reduce first AC network reactive power to described rectifier inverter Transmission.By above-mentioned closed loop control, the first ac voltage measurement value U* can be reduced_{AC_1a,}U*_{AC_1b,}U*_{AC_1c}With the first alternating current Pressure reference value V_{AC_1a,}V_{AC_1b,}V_{AC_1c}Between difference, preferably the alternating voltage of the first AC network can be adjusted to substantially First alternating voltage reference value V_{AC_1a,}V_{AC_1b,}V_{AC_1c}.Thus reduce the merit sent due to the power generating equipment of such as new forms of energy Rate, has the instability of the alternating voltage that fluctuation brought within a period of time.This reduce undulatory property power supply, such as new forms of energy, The interference bringing grid stability, improves stability and the reliability of electrical network containing undulatory property power supply.

By change Trigger Angle/flame-out angle (in the case of keeping DC voltage to be basically unchanged (the least tolerance interval), The exchange of reactive power between AC system and straight-flow system can be changed.And then play the effect of stable AC system voltage Really.Therefore, there is no need to rely on the alternating current filter of frequently regulation high-voltage direct current and shnt capacitor to regulate AC system And the reactive power exchange between straight-flow system, and then stablize AC system voltage.

In an embodiment of the present invention, if the first ac voltage measurement value U* calculated by computing module 110_{AC_1a,} U*_{AC_1b,}U*_{AC_1c}With the first alternating voltage reference value V_{AC_1a,}V_{AC_1b,}V_{AC_1c}Between difference be just, then rectifier inverter control Module 110 can turn down high-voltage dc transmission by sending the order of the angle of ignition α of the rectifier inverter of increase to rectifier inverter The DC voltage value U of the rectifier inverter of electricity system_DCR, and then increase idle to described rectifier inverter of the first AC network Power transmits；Further, inverter control module 111 can be by sending the inverter of reduction to inverter/converter Flame-out angle γ reduces DC current values I of inverter_DC.Whereas if the first friendship calculated by described computing module Stream voltage measuring value U*_{AC_1a,}U*_{AC_1b,}U*_{AC_1c}With the first alternating voltage reference value V_{AC_1a,}V_{AC_1b,}V_{AC_1c}Between difference be Negative, then rectifier inverter control module 110 can be by sending the life of the angle of ignition α of the rectifier inverter of reduction to rectifier inverter The DC voltage value U of the rectifier inverter of HVDC transmission system is turned down in order_DCR, and then reduce the first AC network to institute State the reactive power transmission of rectifier inverter；Further, inverter control module 111 can be by sending to inverter/converter The flame-out angle γ of the inverter increased heightens DC current values I of inverter_DC。

Fig. 3 illustrates the computing module of controller according to another embodiment of the invention, inverter control module With rectifier inverter control module.Being with the embodiment difference shown in Fig. 2 according to the embodiment shown in Fig. 3, the former is also Add rectification side converter power transformer and divide the regulation changing head.In order to expand the range of accommodation of HVDC transmission system and keep system System is in good running status, it is also possible to be aided with the regulation of converter power transformer voltage.Generally use on-load switching branch joint Device be adjusted.Relevant converter power transformer divides the technical scheme of the regulation changing head to refer to " direct current transportation ", and Zhejiang University is sent out Electricity teaching and research group direct current transportation scientific research group, February nineteen eighty-two the first edition.As it is shown on figure 3, inverter control module 111 is additionally based upon Converter power transformer tap uses zero load alternating voltage in rectifier inverter side to keep certain and regulates described HVDC transmission system DC current values I_DC.In the present embodiment, inverter control module 111 also includes adder, and it is to corresponding to rectification The flame-out angle γ * of the inverter of inverter side zero load alternating voltage and according to the inversion change of current obtained by the embodiment of Fig. 2 The flame-out angle fine adjustment value Δ γ of device makees addition, so that it is determined that flame-out angle reference value γ of inverter_ref.Reality except Fig. 2 Executing outside the stability that example can improve the first AC network, Fig. 3 embodiment can also reduce rectification side converter power transformer and divide and change head Action.Thus, improve the reliability of system, reduce system maintenance operating cost.

Preferably, inverter control module 111 can also include clipping unit, and it will ensure controlled high-voltage direct current DC voltage value is regulated in predetermined scope.This is so that this high-voltage direct current is controlling rectification current conversion station alternating voltage While, hvdc transmission line is lost also in tolerance interval.As it is shown on figure 3, the effect of ' max ' functional device is finally to put out The reference value at fire angle compares with 17 °, takes that bigger value, reduces the high-voltage direct current commutation brought owing to flame-out angle is too small Failed risk.

Although some preferred embodiment with reference to the present invention illustrate and describes the present invention, but those skilled in the art should When understanding, in the case of without departing substantially from the spirit and scope of the present invention as defined in appended claims, can be in form Above and in details, it is made a variety of changes.

Claims (12)

1. the control of the HVDC transmission system for power is transmitted to the second AC network from the first AC network System, including:

Voltage measurement parts, for measuring the first alternating voltage of described first AC network；With

Controller, including:

Computing module, for calculating the difference between the first ac voltage measurement value and the first alternating voltage reference value；

Rectifier inverter control module, for regulating the rectifier inverter of described HVDC transmission system based on described difference DC voltage value is to regulate reactive power that described rectifier inverter absorbs/send and then reducing described first alternating voltage and survey Difference between value and the first alternating voltage reference value；With

Inverter control module, regulates described HVDC for DC voltage value based on the rectifier inverter after regulation The DC current values of transmission system is to keep being transmitted through described aerial line HVDC transmission system after the adjustment Active power constant.

2. control system as claimed in claim 1, wherein:

Described inverter control module is additionally based upon converter power transformer tap and uses rectifier inverter side zero load alternating voltage Keep certain DC current values regulating described HVDC transmission system.

3. control system as claimed in claim 1, wherein:

The DC voltage value of the rectifier inverter of described HVDC transmission system is regulated in predetermined scope.

4. the control system as described in claim 1 or 2 or 3,

If the difference between the first ac voltage measurement value calculated by described computing module and the first alternating voltage reference value Value for just, then increases by the first AC network and transmits to the reactive power of described rectifier inverter；And

If the difference between the first ac voltage measurement value calculated by described computing module and the first alternating voltage reference value Value is negative, then reduce described first AC network and transmit to the reactive power of described rectifier inverter.

5. control system as claimed in claim 4, wherein:

If the difference between the first ac voltage measurement value calculated by described computing module and the first alternating voltage reference value Value for just, then increases by first AC network nothing to described rectifier inverter by the angle of ignition of the described rectifier inverter of increase Merit power transmits；And

If the difference between the first ac voltage measurement value calculated by described computing module and the first alternating voltage reference value Value is negative, then reduce first AC network nothing to described rectifier inverter by the angle of ignition of the described rectifier inverter of reduction Merit power transmits.

6. control system as claimed in claim 5, wherein:

Can turn down/heighten the unidirectional current of described rectifier inverter by increasing/reduce the angle of ignition of described rectifier inverter Pressure value, can heighten by increasing/reduce the flame-out angle of described inverter/turn down the unidirectional current of described inverter Flow valuve, so that active power holding transmit to the second AC network from the first AC network by high-voltage direct current is not Become, but the reactive power exchange between the first AC network and high-voltage direct current is adjustable.

7. the control of the HVDC transmission system for power is transmitted to the second AC network from the first AC network Method, including:

Measure the first alternating voltage of described first AC network；

Calculate the difference between the first ac voltage measurement value and the first alternating voltage reference value；

The DC voltage value of the rectifier inverter of described HVDC transmission system is regulated so that regulation is described based on described difference Reactive power that rectifier inverter absorbs/sends and then reduce described first ac voltage measurement value and the first alternating voltage reference Difference between value；And

Based on regulation after rectifier inverter DC voltage value regulate described HVDC transmission system DC current values with Just keep the active power transmitted through the aerial line of described HVDC transmission system after the adjustment constant.

8. control method as claimed in claim 7, also includes:

Use zero load alternating voltage in rectifier inverter side to keep certain based on converter power transformer tap and regulate described HVDC The DC current values of transmission system.

9. control method as claimed in claim 7, wherein:

The DC voltage value of the rectifier inverter of described HVDC transmission system is regulated in predetermined scope.

10. the control method as described in claim 7 or 8 or 9, wherein:

If the difference between the first ac voltage measurement value calculated and the first alternating voltage reference value for just, then increases by the One AC network transmits to the reactive power of described rectifier inverter；And

If the difference between the first ac voltage measurement value calculated and the first alternating voltage reference value is negative, then reduce institute State the first AC network to transmit to the reactive power of described rectifier inverter.

11. control methods as claimed in claim 10, wherein:

If the difference between the first ac voltage measurement value calculated by described computing module and the first alternating voltage reference value Value for just, then increases by first AC network nothing to described rectifier inverter by the angle of ignition of the described rectifier inverter of increase Merit power transmits；And

If the difference between the first ac voltage measurement value calculated by described computing module and the first alternating voltage reference value Value is negative, then reduce first AC network nothing to described rectifier inverter by the angle of ignition of the described rectifier inverter of reduction Merit power transmits.

12. control methods as claimed in claim 11, wherein:

Can turn down/heighten the unidirectional current of described rectifier inverter by increasing/reduce the angle of ignition of described rectifier inverter Pressure value, can heighten by increasing/reduce the flame-out angle of described inverter/turn down the unidirectional current of described inverter Flow valuve, so that active power holding transmit to the second AC network from the first AC network by high-voltage direct current is not Become, but the reactive power exchange between the first AC network and high-voltage direct current is adjustable.