WO2019109841A1 - 一种直流输电系统电压电流控制方法及装置 - Google Patents

一种直流输电系统电压电流控制方法及装置 Download PDF

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Publication number
WO2019109841A1
WO2019109841A1 PCT/CN2018/117937 CN2018117937W WO2019109841A1 WO 2019109841 A1 WO2019109841 A1 WO 2019109841A1 CN 2018117937 W CN2018117937 W CN 2018117937W WO 2019109841 A1 WO2019109841 A1 WO 2019109841A1
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Prior art keywords
voltage
current
reference value
control terminal
control
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PCT/CN2018/117937
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English (en)
French (fr)
Inventor
鲁江
卢宇
董云龙
王永平
田杰
汪楠楠
赵文强
胡兆庆
王柯
肖建民
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南京南瑞继保电气有限公司
南京南瑞继保工程技术有限公司
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Priority to KR1020207010629A priority Critical patent/KR102196898B1/ko
Priority to JP2020528167A priority patent/JP6817501B1/ja
Priority to RU2020113675A priority patent/RU2732191C1/ru
Priority to CA3080015A priority patent/CA3080015C/en
Priority to US16/767,922 priority patent/US11289905B2/en
Priority to EP18885604.1A priority patent/EP3681006B1/en
Publication of WO2019109841A1 publication Critical patent/WO2019109841A1/zh

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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J1/00Circuit arrangements for dc mains or dc distribution networks
    • H02J1/08Three-wire systems; Systems having more than three wires
    • H02J1/082Plural DC voltage, e.g. DC supply voltage with at least two different DC voltage levels
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J1/00Circuit arrangements for dc mains or dc distribution networks
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for ac mains or ac distribution networks
    • H02J3/36Arrangements for transfer of electric power between ac networks via a high-tension dc link
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for ac mains or ac distribution networks
    • H02J3/36Arrangements for transfer of electric power between ac networks via a high-tension dc link
    • H02J2003/365Reducing harmonics or oscillations in HVDC
    • 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
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/60Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

Definitions

  • the invention belongs to the technical field of direct current transmission, and particularly relates to a voltage and current control method for a direct current transmission system, and a voltage current control device for a direct current transmission system.
  • HVDC transmission systems can be divided into two types: conventional direct current transmission systems based on thyristor converter valves (LCC-HVDC) and flexible direct current transmission systems based on fully-regulated voltage source converter valves (VSC-HVDC).
  • LCC-HVDC thyristor converter valves
  • VSC-HVDC fully-regulated voltage source converter valves
  • the conventional DC transmission system has low cost, low loss and mature operation technology.
  • Most of the DC transmission systems currently in operation in the world are LCC-HVDC systems, but the conventional DC transmission system is prone to commutation failure and AC exchange on the inverter side.
  • the system has strong dependence, needs to absorb a large amount of reactive power, and has a large area of converter station.
  • the new generation of flexible DC transmission system has the ability to realize active power and reactive power decoupling control, and can be used to passive networks.
  • the control method of controlling the direct current of the rectifier station and controlling the direct current voltage of the inverter station is generally adopted, and the DC voltage control target generally controls the DC voltage at the outlet of the rectifier station to reach the rectification set by the operating personnel. Station DC voltage reference value. Due to the existence of DC line resistance, the line voltage drop will increase with the increase of DC current. Therefore, the inverter station needs to adjust the DC voltage output as the DC current changes to ensure that the DC voltage of the rectifier station is maintained at the set reference. Value level. In addition, when the AC system of the transmitting end where the rectifier station is located causes a large drop in the AC voltage, the rectifier station will lose control of the DC current. In this case, the inverter needs to maintain the DC current by controlling the DC voltage reduction. control.
  • the DC voltage outputted by the voltage source converter cannot be directly controlled according to the DC voltage reference value, and can only be indirectly controlled by changing the capacitance voltage of the voltage source converter or the sub-module voltage. And the DC voltage cannot be reduced by a large margin. Therefore, it is necessary to find a method for effectively controlling the DC voltage and DC current of a DC transmission system including a voltage source converter.
  • the object of the present invention is to provide a method and a device for controlling the voltage and current of a direct current transmission system to meet the operational needs of a direct current transmission system including a voltage source converter.
  • the technical solution adopted by the present invention is to provide a DC current transmission system voltage and current control method
  • the DC transmission system includes at least one DC pole
  • the DC pole includes a DC current control terminal and a DC voltage control terminal.
  • the DC voltage control terminal of the DC pole includes at least one voltage source converter, and the control method includes:
  • the DC voltage reference value U dcref required for controlling the DC voltage of the DC voltage control terminal is obtained, and the DC voltage measurement value U dV of the DC voltage control terminal voltage source converter is obtained;
  • the DC current measurement value I dc is compared with the DC current reference value I dcref , and then the DC current controller of the input voltage source converter performs closed-loop control, and the DC current controller Outputting a DC voltage reference value U dVref as a voltage source converter;
  • the DC voltage reference value U dVref of the voltage source converter As the bridge source voltage DC offset of the voltage source converter, and the DC voltage reference value U dVref of the voltage source converter is made to be different from the DC voltage measurement value U dV and then input to the DC voltage control of the input voltage source converter
  • the loop performs closed-loop control to control the DC voltage or DC current of the DC pole.
  • the DC voltage reference value required to control the DC voltage of the DC voltage control terminal is used as the upper limit of the DC source controller output of the voltage source converter.
  • the method for obtaining a DC current reference value of a DC-DC voltage control terminal includes subtracting a current deviation amount from a DC current reference value of the DC-pole DC current control terminal as a DC current reference value of the DC voltage control terminal.
  • the DC pole DC voltage control terminal contains two or more voltage source converters operating in series
  • one of the voltage source converters is selected as the master converter
  • the other converters are slave converters.
  • the DC voltage reference value of each slave converter is synchronously maintained with the DC voltage reference value of the master converter.
  • the DC voltage reference value U dcref required to control the DC voltage is controlled.
  • the DC voltage reference value U dVref is used as the inverter of each operating voltage source, wherein N is a positive integer.
  • the present invention also provides a DC current transmission system voltage and current control device, the DC transmission system includes at least one DC pole, the DC pole includes a DC current control terminal and a DC voltage control terminal, and the DC voltage control terminal of the DC pole includes At least one voltage source converter, the control device comprises: an acquisition unit, a DC voltage reference value calculation unit, and a DC voltage control unit, wherein:
  • the collecting unit is configured to obtain a DC voltage reference value U dcref required for controlling a DC voltage of a DC pole DC voltage control terminal according to a DC voltage control target of the DC pole, and a DC voltage measurement value U dV of the DC voltage control terminal voltage source converter DC current reference value I dcref and DC current measurement value I dc of the DC voltage control terminal;
  • the DC voltage reference value calculation unit is configured to calculate a DC voltage reference value U dVref of the DC source DC voltage control terminal voltage source converter; and when the DC pole DC voltage control terminal actually controls the DC voltage, the DC voltage is required to be controlled DC voltage reference U dcref converter as a voltage source a DC voltage reference value U dVref; when the DC electrode DC voltage control terminal actual control DC current, DC current measurement values I dc after the DC current reference value I dcref calculating the difference between the input
  • the DC current controller of the voltage source converter performs closed-loop control, and the output of the DC current controller is used as a DC voltage reference value U dVref of the voltage source converter;
  • the DC voltage control unit is configured to use a DC voltage reference value U dVref of the voltage source converter As the bridge source voltage DC offset of the voltage source converter, and the DC voltage reference value U dVref of the voltage source converter is made to be different from the DC voltage measurement value U dV and then input to the DC voltage control of the input voltage source converter
  • the loop performs closed-loop control to control the DC voltage or DC current of the DC pole.
  • the DC voltage reference value calculation unit further includes a DC current controller upper limit setting subunit, and the DC voltage reference value required for the DC voltage DC control terminal to control the DC voltage is used as an upper limit of the voltage source converter DC current controller output.
  • the method for obtaining the DC current reference value of the DC pole DC voltage control terminal by the collecting unit comprises: subtracting a current deviation amount from the DC current reference value of the DC pole DC current control terminal as a DC current reference value of the DC voltage control terminal.
  • the DC voltage DC voltage control terminal includes two or more voltage source converters that are operated in series, one of the voltage source converters is selected as the main control inverter, and the other The converters are slave-controlled converters, and the DC voltage reference values of the slave converters are kept in synchronization with the DC voltage reference value of the master converter.
  • the DC voltage reference value calculation unit when the DC voltage DC voltage control terminal includes two or more voltage source converters that are operated in series, if the DC voltage DC voltage control terminal actually controls the DC voltage, the DC voltage is controlled.
  • the DC voltage reference value U dcref required for the voltage is distributed according to the total number N of voltage source converters operating in series and is used as the DC voltage reference value U dVref of each operating voltage source converter, wherein N is a positive integer.
  • the invention provides a voltage and current control method and device for a direct current transmission system.
  • a voltage source converter of a DC voltage direct current voltage control terminal By adopting the proposed control strategy for a voltage source converter of a DC voltage direct current voltage control terminal, a DC voltage of a direct current transmission system including a voltage source converter can be realized. , effective control of DC current.
  • FIG. 1 is a flow chart of a method for controlling voltage and current of a direct current transmission system provided by the present invention
  • FIG. 2 is a schematic diagram showing the principle of a control strategy of a DC source DC voltage control terminal voltage source converter according to the present invention
  • FIG. 3 is a schematic diagram of a topology of a voltage source converter operating in two or more series in series in the present invention
  • FIG. 4 is a structural block diagram of a voltage and current control device for a direct current transmission system provided by the present invention.
  • the invention provides a voltage and current control method for a direct current transmission system, and a voltage current control device for a direct current transmission system, which is used for realizing effective control of a direct current voltage and a direct current of a direct current transmission system including a voltage source converter, and satisfies the voltage containing The operation of the DC converter of the source converter is required.
  • the solution of the present invention is to provide a DC power transmission system voltage and current control method
  • the DC power transmission system includes at least one DC pole
  • the DC pole includes a DC current control terminal and a DC voltage control terminal
  • the DC voltage control terminal of the DC pole includes at least one voltage source converter
  • the control method is as shown in FIG. 1:
  • the DC voltage reference value U dcref required for controlling the DC voltage of the DC voltage control terminal is obtained, and the DC voltage measurement value U dV of the DC voltage control terminal voltage source converter is obtained;
  • the DC voltage control target of the DC pole is generally the DC voltage reference value of the rectifier station set by the operator.
  • the DC voltage reference value U dcref required to control the DC voltage is equal to the operator setting.
  • the rectifier station DC voltage reference value is subtracted from the DC line voltage drop.
  • the DC voltage control terminal of the DC pole is responsible for controlling the DC voltage under normal operating conditions; however, when the AC system of the transmitting end where the rectifier station is located causes a large drop in the AC voltage, the rectifier station will lose control of the DC current. At this time, the inverter station needs to reduce the DC voltage by control to maintain the control of the DC current.
  • the DC current measurement value I dc is compared with the DC current reference value I dcref , and then the DC current controller of the input voltage source converter performs closed-loop control, and the DC current controller Outputting a DC voltage reference value U dVref as a voltage source converter;
  • u vjref is the j-phase AC voltage reference wave.
  • the control of the voltage source converter is realized by controlling the voltage of the bridge arm of the upper and lower arms of each phase.
  • the bridge arm voltage includes two parts: the DC bias amount and the AC voltage reference wave.
  • the voltage source converter of the extreme DC voltage control terminal adopts the control strategy shown in Figure 2:
  • the DC voltage reference value U dVref of the voltage source converter As the DC offset of the voltage of the inverter source bridge voltage, and the DC voltage reference value U dVref of the voltage source converter is made to be different from the DC voltage measurement value U dV , the DC voltage of the input voltage source converter is controlled. Ring, DC voltage control The output of the outer loop is limited by the inner loop current limit to generate the d-axis current inner loop reference value i dref and input to the current source inner loop of the voltage source converter, and the current control inner loop output voltage source is commutated.
  • the AC voltage reference wave of the device; using the bridge arm voltage DC offset of the voltage source converter and the AC voltage reference wave to control the bridge arm voltage, the DC direct current voltage or the DC current can be controlled.
  • the DC voltage reference value required for controlling the DC voltage of the DC voltage control terminal is used as the voltage.
  • the upper limit of the source converter DC current controller output is used as the voltage.
  • the method for obtaining a DC current reference value of a DC-DC voltage control terminal includes subtracting a current deviation amount from a DC current reference value of the DC-pole DC current control terminal as a DC current reference value of the DC voltage control terminal.
  • the DC pole DC voltage control terminal comprises two or more voltage source converters operating in series, as shown in FIG. 3, in order to realize the operation equalization of each series voltage source converter, one of the voltage source commutation is selected.
  • the main control converter the other converters are slave converters, and the DC voltage reference values of the slave inverters are kept in synchronization with the DC voltage reference value of the main inverter;
  • the DC voltage control terminal actually controls the DC voltage the DC voltage reference value U dcref required to control the DC voltage is distributed according to the total number N of voltage source converters connected in series and is used as the converter of each operating voltage source.
  • DC voltage reference value U dVref where N is a positive integer.
  • the invention also provides a voltage and current control device for a direct current transmission system, as shown in FIG. 4, which comprises an acquisition unit, a DC voltage reference value calculation unit, and a DC voltage control unit, wherein:
  • the collecting unit is configured to obtain a DC voltage reference value U dcref required for controlling a DC voltage of a DC pole DC voltage control terminal according to a DC voltage control target of the DC pole, and a DC voltage measurement value U dV of the DC voltage control terminal voltage source converter DC current reference value I dcref and DC current measurement value I dc of the DC voltage control terminal;
  • the DC voltage reference value calculation unit is configured to calculate a DC voltage reference value U dVref of the DC source DC voltage control terminal voltage source converter; and when the DC pole DC voltage control terminal actually controls the DC voltage, the DC voltage is required to be controlled DC voltage reference U dcref converter as a voltage source a DC voltage reference value U dVref; when the DC electrode DC voltage control terminal actual control DC current, DC current measurement values I dc after the DC current reference value I dcref calculating the difference between the input
  • the DC current controller of the voltage source converter performs closed-loop control, and the output of the DC current controller is used as a DC voltage reference value U dVref of the voltage source converter;
  • the DC voltage control unit is configured to use a DC voltage reference value U dVref of the voltage source converter As the bridge source voltage DC offset of the voltage source converter, and the DC voltage reference value U dVref of the voltage source converter is made to be different from the DC voltage measurement value U dV and then input to the DC voltage control of the input voltage source converter
  • the loop performs closed-loop control to control the DC voltage or DC current of the DC pole.
  • the DC voltage reference value calculation unit further includes a DC current controller upper limit setting subunit, and the DC voltage reference value required for the DC voltage DC control terminal to control the DC voltage is used as an upper limit of the voltage source converter DC current controller output.
  • the method for obtaining the DC current reference value of the DC pole DC voltage control terminal by the collecting unit includes subtracting a current deviation amount from the DC current reference value of the DC pole DC current control terminal as a DC current reference value of the DC voltage control terminal.
  • the DC voltage DC voltage control terminal includes two or more voltage source converters that are operated in series, one of the voltage source converters is selected as the main control inverter, and the other The converters are slave-controlled converters, and the DC voltage reference values of the slave converters are kept in synchronization with the DC voltage reference value of the master converter.
  • the DC voltage reference value calculation unit when the DC voltage DC voltage control terminal includes two or more voltage source converters that are operated in series, if the DC voltage DC voltage control terminal actually controls the DC voltage, the DC voltage is controlled.
  • the DC voltage reference value U dcref required for the voltage is distributed according to the total number N of voltage source converters operating in series and is used as the DC voltage reference value U dVref of each operating voltage source converter, wherein N is a positive integer.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)
  • Direct Current Feeding And Distribution (AREA)
  • Inverter Devices (AREA)
  • Rectifiers (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

本发明公开了一种直流输电系统电压电流控制方法,包括:根据直流输电系统直流极的直流电压控制端是否实际控制直流电压计算出直流电压控制端电压源换流器的直流电压参考值,采用计算得到的电压源换流器直流电压参考值的1/2作为电压源换流器的桥臂电压直流偏置量,并将电压源换流器的直流电压参考值与直流电压测量值做差后输入电压源换流器的直流电压控制外环进行闭环控制,实现对直流极直流电压或直流电流的控制。相应地,提供一种直流输电系统电压电流控制装置。本发明可以实现对含有电压源换流器的直流输电系统直流电压、直流电流的有效控制。

Description

一种直流输电系统电压电流控制方法及装置 技术领域
本发明属于直流输电技术领域,具体涉及一种直流输电系统电压电流控制方法,以及一种直流输电系统电压电流控制装置。
背景技术
高压直流输电系统可分为两种类型:基于晶闸管换流阀的常规直流输电系统(LCC-HVDC)和基于全控型电压源换流阀的柔性直流输电系统(VSC-HVDC)。常规直流输电系统成本低、损耗小、运行技术成熟,目前世界上正在运行的直流输电系统绝大部分都是LCC-HVDC系统,但常规直流输电系统存在逆变侧易发生换相失败、对交流系统的依赖性强、需吸收大量无功功率、换流站占地面积大等缺点;而新一代的柔性直流输电系统则具有能够实现有功功率及无功功率解耦控制、可以向无源网络供电、结构紧凑占地面积小、不存在换相失败问题等优点,但也存在成本较高的缺陷。因此,综合常规直流输电和柔性直流输电两者优点,一端换流站采用晶闸管换流阀、另一端换流站采用电压源换流阀的混合直流输电技术具有良好的工程应用前景。远期来看,随着电压源换流阀所用全控器件价格的降低,两端换流站均采用电压源换流阀的柔性直流输电技术也将会得到越来越广泛的应用。
对于直流输电系统,在正常运行状态下,一般采用整流站控制直流电流、逆变站控制直流电压的控制方式,直流电压控制目标一般为控制整流站出口处的直流电压达到运行人员设定的整流站直流电压参考值。由于直流线路电阻的存在,线路电压降会随着直流电流的增大而增大,因此逆变站需要随着直流电流的变化而调整直流电压输出以保证整流站直流电压维持在设定的参考值水平。此外,当整流站所在的送端交流系统发生故障引起交流电压出现较大幅度下降时,整流站将失去对直流电流的控制能力,这时需要逆变站通过控制直流电压降低来维持对直流电流的控制。
在现有的VSC-HVDC控制技术中,电压源换流器输出的直流电压不能根据直流电压参考值直接进行控制,仅能通过改变电压源换流器的电容电压或子模块电容电压来间接 控制,并且直流电压不能较大幅度的降低。因此有必要寻找一种可以实现对含有电压源换流器的直流输电系统直流电压、直流电流进行有效控制的方法。
发明内容
本发明的目的在于针对现有技术不足,提供一种直流输电系统电压电流控制方法及装置,满足含有电压源换流器的直流输电系统的运行需要。
为了达成上述目的,本发明采用的技术方案是:提供一种直流输电系统电压电流控制方法,所述直流输电系统包含至少一个直流极,所述直流极包括直流电流控制端和直流电压控制端,所述直流极的直流电压控制端包含至少一个电压源换流器,所述控制方法包括:
根据直流极的直流电压控制目标获取直流电压控制端控制直流电压所需的直流电压参考值U dcref,并获取直流电压控制端电压源换流器的直流电压测量值U dV
获取直流极直流电压控制端的直流电流参考值I dcref和直流电流测量值I dc
当直流极直流电压控制端实际控制直流电压时,将控制直流电压所需的直流电压参考值U dcref作为电压源换流器的直流电压参考值U dVref
当直流极直流电压控制端实际控制直流电流时,将直流电流测量值I dc与直流电流参考值I dcref做差后输入电压源换流器的直流电流控制器进行闭环控制,直流电流控制器的输出作为电压源换流器的直流电压参考值U dVref
将电压源换流器的直流电压参考值U dVref
Figure PCTCN2018117937-appb-000001
作为电压源换流器的桥臂电压直流偏置量,并将电压源换流器的直流电压参考值U dVref与直流电压测量值U dV做差后输入电压源换流器的直流电压控制外环进行闭环控制,实现对直流极直流电压或直流电流的控制。
将直流极直流电压控制端控制直流电压所需的直流电压参考值作为电压源换流器直流电流控制器输出的上限。
所述获取直流极直流电压控制端直流电流参考值的方法包括,将直流极直流电流控制端的直流电流参考值减去一个电流偏差量作为直流电压控制端的直流电流参考值。
当直流极直流电压控制端包含两个或两个以上串联运行的电压源换流器时,选择其中一个电压源换流器作为主控换流器,其他换流器均为从控换流器,各从控换流器的直 流电压参考值同步保持与主控换流器的直流电压参考值相一致。
当直流极直流电压控制端包含两个或两个以上串联运行的电压源换流器时,如直流极直流电压控制端实际控制直流电压,则将控制直流电压所需的直流电压参考值U dcref按照串联运行的电压源换流器总个数N进行分配并作为各运行电压源换流器的直流电压参考值U dVref,其中
Figure PCTCN2018117937-appb-000002
N为正整数。
本发明还提供一种直流输电系统电压电流控制装置,所述直流输电系统包含至少一个直流极,所述直流极包括直流电流控制端和直流电压控制端,所述直流极的直流电压控制端包含至少一个电压源换流器,所述控制装置包括:采集单元、直流电压参考值计算单元、直流电压控制单元,其中:
所述采集单元用于根据直流极的直流电压控制目标获取直流极直流电压控制端控制直流电压所需的直流电压参考值U dcref、直流电压控制端电压源换流器的直流电压测量值U dV、直流电压控制端的直流电流参考值I dcref和直流电流测量值I dc
所述直流电压参考值计算单元用于计算直流极直流电压控制端电压源换流器的直流电压参考值U dVref;当直流极直流电压控制端实际控制直流电压时,将控制直流电压所需的直流电压参考值U dcref作为电压源换流器的直流电压参考值U dVref;当直流极直流电压控制端实际控制直流电流时,直流电流测量值I dc与直流电流参考值I dcref做差后输入电压源换流器的直流电流控制器进行闭环控制,直流电流控制器的输出作为电压源换流器的直流电压参考值U dVref
所述直流电压控制单元用于将电压源换流器的直流电压参考值U dVref
Figure PCTCN2018117937-appb-000003
作为电压源换流器的桥臂电压直流偏置量,并将电压源换流器的直流电压参考值U dVref与直流电压测量值U dV做差后输入电压源换流器的直流电压控制外环进行闭环控制,实现对直流极直流电压或直流电流的控制。
所述直流电压参考值计算单元还包括直流电流控制器上限设置子单元,将直流极直流电压控制端控制直流电压所需的直流电压参考值作为电压源换流器直流电流控制器输出的上限。
所述采集单元获取直流极直流电压控制端直流电流参考值的方法包括,将直流极直流电流控制端的直流电流参考值减去一个电流偏差量作为直流电压控制端的直流电流 参考值。
所述直流电压参考值计算单元中,当直流极直流电压控制端包含两个或两个以上串联运行的电压源换流器时,选择其中一个电压源换流器作为主控换流器,其他换流器均为从控换流器,各从控换流器的直流电压参考值同步保持与主控换流器的直流电压参考值相一致。
所述直流电压参考值计算单元中,当直流极直流电压控制端包含两个或两个以上串联运行的电压源换流器时,如直流极直流电压控制端实际控制直流电压,则将控制直流电压所需的直流电压参考值U dcref按照串联运行的电压源换流器总个数N进行分配并作为各运行电压源换流器的直流电压参考值U dVref,其中
Figure PCTCN2018117937-appb-000004
N为正整数。
本发明的有益效果是:
本发明提供一种直流输电系统电压电流控制方法及装置,通过对直流极直流电压控制端的电压源换流器采取所提出的控制策略,可以实现对含有电压源换流器的直流输电系统直流电压、直流电流的有效控制。
附图说明
图1是本发明提供的直流输电系统电压电流控制方法的流程图;
图2是本发明中直流极直流电压控制端电压源换流器的控制策略原理示意图;
图3是本发明中两个或两个以上串联运行的电压源换流器拓扑示意图;
图4是本发明提供的直流输电系统电压电流控制装置的结构框图。
具体实施方式
以下将结合附图及具体实施例,对本发明的技术方案进行详细说明。
本发明提供一种直流输电系统电压电流控制方法,以及一种直流输电系统电压电流控制装置,用于实现对含有电压源换流器的直流输电系统直流电压、直流电流的有效控制,满足含有电压源换流器的直流输电系统的运行需要。
为了达成上述目的,本发明的解决方案是提供一种直流输电系统电压电流控制方法,所述直流输电系统包含至少一个直流极,所述直流极包括直流电流控制端和直流电压控制端,所述直流极的直流电压控制端包含至少一个电压源换流器,所述控制方法如 图1所示:
根据直流极的直流电压控制目标获取直流电压控制端控制直流电压所需的直流电压参考值U dcref,并获取直流电压控制端电压源换流器的直流电压测量值U dV
直流极的直流电压控制目标一般为运行人员设定的整流站直流电压参考值,对处于逆变站的直流电压控制端,其控制直流电压所需的直流电压参考值U dcref等于运行人员设定的整流站直流电压参考值减去直流线路的电压降。
获取直流极直流电压控制端的直流电流参考值I dcref和直流电流测量值I dc
直流极的直流电压控制端在正常运行情况下负责控制直流电压;但当整流站所在的送端交流系统发生故障引起交流电压出现较大幅度下降时,整流站将失去对直流电流的控制能力,这时需要逆变站通过控制降低直流电压来维持对直流电流的控制。
当直流极直流电压控制端实际控制直流电压时,将控制直流电压所需的直流电压参考值U dcref作为电压源换流器的直流电压参考值U dVref
当直流极直流电压控制端实际控制直流电流时,将直流电流测量值I dc与直流电流参考值I dcref做差后输入电压源换流器的直流电流控制器进行闭环控制,直流电流控制器的输出作为电压源换流器的直流电压参考值U dVref
对于电压源换流器,其运行特性如式(1)所示:
Figure PCTCN2018117937-appb-000005
其中,u pj和u nj分别为电压源换流器j(j=a,b,c)相上、下桥臂电压,
Figure PCTCN2018117937-appb-000006
为桥臂电压直流偏执量,u vjref为j相的交流电压参考波。
对电压源换流器的控制是通过控制各相上、下桥臂的桥臂电压来实现的,由式(1)可见,桥臂电压包含直流偏执量和交流电压参考波两部分,对直流极直流电压控制端的电压源换流器,采用如图2所示的控制策略:
将电压源换流器的直流电压参考值U dVref
Figure PCTCN2018117937-appb-000007
作为电压源换流器桥臂电压的直流偏置量,并将电压源换流器的直流电压参考值U dVref与直流电压测量值U dV做差后输入电压源换流器的直流电压控制外环,直流电压控制外环的输出经内环电流限值限幅后产生d 轴电流内环参考值i dref并输入电压源换流器的电流控制内环,电流控制内环输出电压源换流器的交流电压参考波;采用所述电压源换流器的桥臂电压直流偏置量和交流电压参考波对桥臂电压进行控制,可以实现对直流极直流电压或直流电流的控制。
为实现直流极直流电压控制端在实际控制直流电压和实际控制直流电流两种情况下直流电压参考值的自动平滑切换,将直流极直流电压控制端控制直流电压所需的直流电压参考值作为电压源换流器直流电流控制器输出的上限。
所述获取直流极直流电压控制端直流电流参考值的方法包括,将直流极直流电流控制端的直流电流参考值减去一个电流偏差量作为直流电压控制端的直流电流参考值。
当直流极直流电压控制端包含两个或两个以上串联运行的电压源换流器时,如图3所示,为实现各串联电压源换流器的运行均衡,选择其中一个电压源换流器作为主控换流器,其他换流器均为从控换流器,各从控换流器的直流电压参考值同步保持与主控换流器的直流电压参考值相一致;另外,当直流极直流电压控制端实际控制直流电压时,将控制直流电压所需的直流电压参考值U dcref按照串联运行的电压源换流器总个数N进行分配并作为各运行电压源换流器的直流电压参考值U dVref,其中
Figure PCTCN2018117937-appb-000008
N为正整数。
本发明还提供一种直流输电系统电压电流控制装置,如图4所示,其包括采集单元、直流电压参考值计算单元、直流电压控制单元,其中:
所述采集单元用于根据直流极的直流电压控制目标获取直流极直流电压控制端控制直流电压所需的直流电压参考值U dcref、直流电压控制端电压源换流器的直流电压测量值U dV、直流电压控制端的直流电流参考值I dcref和直流电流测量值I dc
所述直流电压参考值计算单元用于计算直流极直流电压控制端电压源换流器的直流电压参考值U dVref;当直流极直流电压控制端实际控制直流电压时,将控制直流电压所需的直流电压参考值U dcref作为电压源换流器的直流电压参考值U dVref;当直流极直流电压控制端实际控制直流电流时,直流电流测量值I dc与直流电流参考值I dcref做差后输入电压源换流器的直流电流控制器进行闭环控制,直流电流控制器的输出作为电压源换流器的直流电压参考值U dVref
所述直流电压控制单元用于将电压源换流器的直流电压参考值U dVref
Figure PCTCN2018117937-appb-000009
作为电压 源换流器的桥臂电压直流偏置量,并将电压源换流器的直流电压参考值U dVref与直流电压测量值U dV做差后输入电压源换流器的直流电压控制外环进行闭环控制,实现对直流极直流电压或直流电流的控制。
所述直流电压参考值计算单元还包括直流电流控制器上限设置子单元,将直流极直流电压控制端控制直流电压所需的直流电压参考值作为电压源换流器直流电流控制器输出的上限。
所述采集单元获取直流极直流电压控制端直流电流参考值的方法包括,将直流极直流电流控制端的直流电流参考值减去一个电流偏差量作为直流电压控制端的直流电流参考值。
所述直流电压参考值计算单元中,当直流极直流电压控制端包含两个或两个以上串联运行的电压源换流器时,选择其中一个电压源换流器作为主控换流器,其他换流器均为从控换流器,各从控换流器的直流电压参考值同步保持与主控换流器的直流电压参考值相一致。
所述直流电压参考值计算单元中,当直流极直流电压控制端包含两个或两个以上串联运行的电压源换流器时,如直流极直流电压控制端实际控制直流电压,则将控制直流电压所需的直流电压参考值U dcref按照串联运行的电压源换流器总个数N进行分配并作为各运行电压源换流器的直流电压参考值U dVref,其中
Figure PCTCN2018117937-appb-000010
N为正整数。
以上实施例仅为说明本发明的技术思想,不能以此限定本发明的保护范围,凡是按照本发明提出的技术思想,在技术方案基础上所做的任何改动,均落入本发明保护范围之内。

Claims (10)

  1. 一种直流输电系统电压电流控制方法,所述直流输电系统包含至少一个直流极,所述直流极包括直流电流控制端和直流电压控制端,所述直流极的直流电压控制端包含至少一个电压源换流器,其特征在于,所述控制方法包括:
    根据直流极的直流电压控制目标获取直流电压控制端控制直流电压所需的直流电压参考值U dcref,并获取直流电压控制端电压源换流器的直流电压测量值U dV
    获取直流极直流电压控制端的直流电流参考值I dcref和直流电流测量值I dc
    当直流极直流电压控制端实际控制直流电压时,将控制直流电压所需的直流电压参考值U dcref作为电压源换流器的直流电压参考值U dVref
    当直流极直流电压控制端实际控制直流电流时,将直流电流测量值I dc与直流电流参考值I dcref做差后输入电压源换流器的直流电流控制器进行闭环控制,直流电流控制器的输出作为电压源换流器的直流电压参考值U dVref
    将电压源换流器的直流电压参考值U dVref
    Figure PCTCN2018117937-appb-100001
    作为电压源换流器的桥臂电压直流偏置量,并将电压源换流器的直流电压参考值U dVref与直流电压测量值U dV做差后输入电压源换流器的直流电压控制外环进行闭环控制,实现对直流极直流电压或直流电流的控制。
  2. 如权利要求1所述的一种直流输电系统电压电流控制方法,其特征在于:
    将直流极直流电压控制端控制直流电压所需的直流电压参考值作为电压源换流器直流电流控制器输出的上限。
  3. 如权利要求1所述的一种直流输电系统电压电流控制方法,其特征在于:
    所述获取直流极直流电压控制端直流电流参考值的方法包括,将直流极直流电流控制端的直流电流参考值减去一个电流偏差量作为直流电压控制端的直流电流参考值。
  4. 如权利要求1所述的一种直流输电系统电压电流控制方法,其特征在于:
    当直流极直流电压控制端包含两个或两个以上串联运行的电压源换流器时,选择其中一个电压源换流器作为主控换流器,其他换流器均为从控换流器,各从控换流器的直流电压参考值同步保持与主控换流器的直流电压参考值相一致。
  5. 如权利要求1所述的一种直流输电系统电压电流控制方法,其特征在于:
    当直流极直流电压控制端包含两个或两个以上串联运行的电压源换流器时,如直流极直流电压控制端实际控制直流电压,则将控制直流电压所需的直流电压参考值U dcref按照串联运行的电压源换流器总个数N进行分配并作为各运行电压源换流器的直流电压参考值U dVref,其中
    Figure PCTCN2018117937-appb-100002
    N为正整数。
  6. 一种直流输电系统电压电流控制装置,所述直流输电系统包含至少一个直流极,所述直流极包括直流电流控制端和直流电压控制端,所述直流极的直流电压控制端包含至少一个电压源换流器,其特征在于,所述控制装置包括:采集单元、直流电压参考值计算单元、直流电压控制单元,其中:
    所述采集单元用于根据直流极的直流电压控制目标获取直流极直流电压控制端控制直流电压所需的直流电压参考值U dcref、直流电压控制端电压源换流器的直流电压测量值U dV、直流电压控制端的直流电流参考值I dcref和直流电流测量值I dc
    所述直流电压参考值计算单元用于计算直流极直流电压控制端电压源换流器的直流电压参考值U dVref;当直流极直流电压控制端实际控制直流电压时,将控制直流电压所需的直流电压参考值U dcref作为电压源换流器的直流电压参考值U dVref;当直流极直流电压控制端实际控制直流电流时,直流电流测量值I dc与直流电流参考值I dcref做差后输入电压源换流器的直流电流控制器进行闭环控制,直流电流控制器的输出作为电压源换流器的直流电压参考值U dVref
    所述直流电压控制单元用于将电压源换流器的直流电压参考值U dVref
    Figure PCTCN2018117937-appb-100003
    作为电压源换流器的桥臂电压直流偏置量,并将电压源换流器的直流电压参考值U dVref与直流电压测量值U dV做差后输入电压源换流器的直流电压控制外环进行闭环控制,实现对直流极直流电压或直流电流的控制。
  7. 如权利要求6所述的一种直流输电系统电压电流控制装置,其特征在于:
    所述直流电压参考值计算单元还包括直流电流控制器上限设置子单元,将直流极直流电压控制端控制直流电压所需的直流电压参考值作为电压源换流器直流电流控制器输出的上限。
  8. 如权利要求6所述的一种直流输电系统电压电流控制装置,其特征在于:
    所述采集单元获取直流极直流电压控制端直流电流参考值的方法包括,将直流极直 流电流控制端的直流电流参考值减去一个电流偏差量作为直流电压控制端的直流电流参考值。
  9. 如权利要求6所述的一种直流输电系统电压电流控制装置,其特征在于:所述直流电压参考值计算单元中,当直流极直流电压控制端包含两个或两个以上串联运行的电压源换流器时,选择其中一个电压源换流器作为主控换流器,其他换流器均为从控换流器,各从控换流器的直流电压参考值同步保持与主控换流器的直流电压参考值相一致。
  10. 如权利要求6所述的一种直流输电系统电压电流控制装置,其特征在于:所述直流电压参考值计算单元中,当直流极直流电压控制端包含两个或两个以上串联运行的电压源换流器时,如直流极直流电压控制端实际控制直流电压,则将控制直流电压所需的直流电压参考值U dcref按照串联运行的电压源换流器总个数N进行分配并作为各运行电压源换流器的直流电压参考值U dVref,其中
    Figure PCTCN2018117937-appb-100004
    N为正整数。
PCT/CN2018/117937 2017-12-07 2018-11-28 一种直流输电系统电压电流控制方法及装置 WO2019109841A1 (zh)

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