CN105896584B - 一种电压源型换流器控制零序电压的方法 - Google Patents

一种电压源型换流器控制零序电压的方法 Download PDF

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CN105896584B
CN105896584B CN201610249955.XA CN201610249955A CN105896584B CN 105896584 B CN105896584 B CN 105896584B CN 201610249955 A CN201610249955 A CN 201610249955A CN 105896584 B CN105896584 B CN 105896584B
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CN105896584A (zh
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王柯
李钢
卢宇
董云龙
鲁江
胡兆庆
姜田贵
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NR Engineering Co Ltd
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Priority to EP17785430.4A priority patent/EP3416259B1/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
    • H02J2003/365—Reducing harmonics or oscillations in HVDC
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0048—Circuits or arrangements for reducing losses
    • H02M1/0054—Transistor switching losses
    • H02M1/0058—Transistor switching losses by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero
    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Rectifiers (AREA)
  • Inverter Devices (AREA)
  • Direct Current Feeding And Distribution (AREA)

Abstract

本发明提供一种电压源型换流器控制零序电压的方法，当发生交流系统接地故障时，通过检测换流器交流侧的零序电压或者直流侧的零序电压，当检测出的零序电压大于一定值V0ref时，可以提升换流器的直流侧电压到一定值Udc0，从而使换流器交流侧产生合适的参考波，与交流电压匹配，来控制故障站参考波的过调制，抑制直流电压的波动。

Description

一种电压源型换流器控制零序电压的方法
技术领域
本发明涉及电力系统柔性直流输电技术领域，具体涉及一种电压源换流器控制零序电压的方法及装置。
背景技术
柔性直流输电采用电压源型换流器，可以独立、快速控制系统的有功功率和无功功率，从而提高系统的稳定性，抑制系统频率和电压的波动，提高并网交流系统的稳态性能。
对于不接地、高阻或经消弧线圈阀侧接地换流站，若交流系统出现单相接地故障，则故障站将会产生零序电压，交流系统的非故障相电压有可能变为原来的√3倍。此时若保持直流电压不变，则产生的参考波可能达不到额定相电压的√3倍，发生过调制现象，且引起直流侧电压波动，并导致与直流电网相连的其他非故障换流站出现与故障站类似的零序电压。对柔性直流输电系统的安全运行产生不利的影响。
目前，Song Hong-Seok等人的“Dual current control scheme for PWMconverter under unbalance input voltage conditions”(IEEE Transcation onIndustial Electronics.1999,46(5):953-959)针对不对称故障，分别进行负序电压前馈和双序电流内环控制，但只能抑制负序电流。陈海荣博士论文“交流系统故障时VSC-HVDC系统的控制与保护策略研究”正负序不对称故障进行了详细的推导，在采用双序电流环的基础上，负序电流的参考值又分抑制交流侧负序和抑制直流侧二倍频，但这两个目标不能同时实现。以上推到计算只针对负序进行控制，而对于本站故障时零序电压传导到对站，抑制非故障站零序电压并未进行分析研究。
因而，有必要寻找一种电压源换流器控制零序电压的方法和相应装置，通过检测交流侧的零序电压，提升直流侧电压，产生合适的参考波，与交流电压匹配，来控制零序电压，抑制直流电压的波动，保证柔性直流输电系统的稳定安全运行。
发明内容
本发明的目的在于针对现有技术不足,提供一种电压源换流器控制零序电压的方法，通过检测交流侧或者直流侧的零序电压，提升直流侧电压，产生合适的参考波，与交流电压匹配，来控制故障站参考波的过调制，抑制直流电压的波动。保证柔性直流输电系统的稳定安全运行。
为了达成上述目的，本发明采用的技术方案是：
通过检测换流器交流侧的零序电压，当零序电压大于一定值V0ref时，可以提升换流器的直流侧电压到一定值Udc0，直流侧电压提升值满足关系式Udc0>2Um，其中Um为非故障相相电压峰值。从而使换流器交流侧产生合适的参考波，与交流电压匹配，来控制故障站参考波的过调制，抑制直流电压的波动。提升直流电压，有两种方法：通过提升子模块的电容电压到一定值Uc0，来实现提升换流器直流电压的目的；通过投入更多的冗余子模块，来实现提升换流器直流电压的目的。
采用上述方案后，本发明的有益效果为：
(1)本发明提供的电压源换流器控制零序电压的方法，可以控制故障站参考波的过调制，减小直流侧电压波动，使本站的故障对其他非故障站的不利影响降低到最小，保证柔性直流输电系统的稳定安全运行。
附图说明
图1电压源型换流器组成的直流系统示意图；
图2控制零序电压的示意图。
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。
本发明提供一种电压源型换流器控制零序电压的方法，当发生交流系统接地故障时，通过检测换流器交流侧的零序电压或者直流侧的零序电压，当检测出的零序电压大于一定值V0ref时，可以提升换流器的直流侧电压到一定值Udc0，直流侧电压提升值满足关系式Udc0>2Um，其中Um为非故障相相电压峰值，从而使换流器交流侧产生合适的参考波，与交流电压匹配，来控制故障站参考波的过调制，抑制直流电压的波动。
按照本发明中的权利要求1所述方法，对图1所示的电压源型换流器的零序电压控制进行说明：
(1)检测零序电压，当零序电压度大于一定值V0ref时，则认为出现故障，定直流电压控制站开始提升直流电压到Udc0，直流电压满足关系式Udc0>2Um，其中Um为电压源换流器交流侧非故障相的电压峰值，控制零序电压的示意图如图2所示；
(2)直流电压由额定值UdcN提升到Udc0，可通过把子模块电容电压由UcN提升到Uc0来实现，其中
(3)直流电压由额定值UdcN提升到Udc0，也可以通过投入的子模块个数由原来的nN个提升到n0个来实现，其中
(4)当定直流电压站把直流电压提升后，与其相连的非定直流电压站需要把子模块电容电压提升或者投入的子模块个数提升，提升数值如(2)和(3)。
作为具体实施例中的进一步优选方案，所述零序电压的计算可通过交流三相电压相加后除以3得到，也可以通过直流正负极电压相加除以2得到，零序电压故障定值V0ref的取值范围为0.1p.u.<V0ref<1.0p.u.，p.U.是标幺值(per unit)。
作为具体实施例中的进一步优选方案，当两个或两个以上换流器组成直流输电系统时，当某个换流站首先检测到零序电压后，通过站间通讯告知其他换流站，定直流电压站提升直流侧电压，直流侧电压提升值满足关系式Udc0>2Um，其中Um为故障站检测到的非故障相相电压峰值。定功率站的子模块电压或者投入的子模块个数匹配直流侧电压；
其中，子模块电压的定值为Uc0，其中，UcN为故障前的子模块电压，UdcN为故障前的直流电压；
投入的子模块个数为n0，其中，nN为故障前投入的子模块个数，UdcN为故障前的直流电压；
作为具体实施例中的进一步优选方案，换流器的子模块结构包括半桥MMC、全桥MMC或类全桥MMC结构。
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 (4)

1.一种电压源型换流器控制零序电压的方法，其特征在于，当发生交流系统接地故障时，通过检测换流器交流侧的零序电压或者直流侧的零序电压，当检测出的零序电压大于定值V0ref时，提升换流器的直流侧电压到定值Udc0，直流侧电压提升值满足关系式Udc0>2Um，其中Um为非故障相相电压峰值，
直流侧电压的提升采用提高子模块电压的方法，提升子模块电压到定值Uc0，其中，UcN为故障前的子模块电压，UdcN为故障前的直流电压；
或者，采用提高投入子模块个数的方法，提升投入的子模块个数到定值n0，其中，nN为故障前投入的子模块个数，UdcN为故障前的直流电压，从而使换流器交流侧产生合适的参考波，与交流电压匹配，来控制故障站参考波的过调制，抑制直流电压的波动。
2.如权利要求1所述的一种电压源型换流器控制零序电压的方法，其特征在于，所述零序电压的计算可通过交流三相电压相加后除以3得到，或通过直流正负极电压相加除以2得到，零序电压故障定值V0ref的取值范围为0.1p.u.<V0ref<1.0p.u.，p.u.为一个标幺值。
3.如权利要求1所述的一种电压源型换流器控制零序电压的方法，其特征在于，当两个或两个以上换流器组成直流输电系统时，当某个换流器首先检测到零序电压后，通过站间通讯告知其他换流器，定直流电压站提升直流侧电压，直流侧电压提升值满足关系式Udc0>2Um，其中Um为故障站检测到的非故障相相电压峰值，当定直流电压站把直流电压提升后，与其相连的非定直流电压站提升子模块电容电压，或者，提升投入的子模块个数。
4.如权利要求1所述的一种电压源型换流器控制零序电压的方法，其特征在于，换流器的子模块结构包括半桥MMC、全桥MMC或类全桥MMC结构。
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PCT/CN2017/080998 WO2017181946A1 (zh) 2016-04-20 2017-04-19 一种电压源型换流器控制零序电压的方法
EP17785430.4A EP3416259B1 (en) 2016-04-20 2017-04-19 Method for controlling zero sequence voltage of voltage source converter
BR112018068741A BR112018068741A2 (pt) 2016-04-20 2017-04-19 método para controlar tensão de sequência zero de con-versor de fonte de tensão
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