CN115663876B - Main loop parameter design method and system for hybrid cascade extra-high voltage direct current system - Google Patents

Main loop parameter design method and system for hybrid cascade extra-high voltage direct current system Download PDF

Info

Publication number
CN115663876B
CN115663876B CN202211307347.1A CN202211307347A CN115663876B CN 115663876 B CN115663876 B CN 115663876B CN 202211307347 A CN202211307347 A CN 202211307347A CN 115663876 B CN115663876 B CN 115663876B
Authority
CN
China
Prior art keywords
vsc
operating
voltage
range
power
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202211307347.1A
Other languages
Chinese (zh)
Other versions
CN115663876A (en
Inventor
郭铭群
赵峥
李明
李探
吴方劼
黄勇
张进
郑宽
张燕秉
卢亚军
肖鲲
薛英林
马玉龙
徐莹
田园园
蒲莹
熊凌飞
滕尚甫
苏国赟
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
State Grid Corp of China SGCC
State Grid Economic and Technological Research Institute
Original Assignee
State Grid Corp of China SGCC
State Grid Economic and Technological Research Institute
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by State Grid Corp of China SGCC, State Grid Economic and Technological Research Institute filed Critical State Grid Corp of China SGCC
Priority to CN202211307347.1A priority Critical patent/CN115663876B/en
Publication of CN115663876A publication Critical patent/CN115663876A/en
Application granted granted Critical
Publication of CN115663876B publication Critical patent/CN115663876B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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]

Landscapes

  • Supply And Distribution Of Alternating Current (AREA)
  • Control Of Electrical Variables (AREA)

Abstract

本发明涉及直流输电领域,提供一种混合级联特高压直流系统主回路参数设计方法及系统,包括:确定混合级联特高压直流系统的运行方式;确定受端VSC和LCC的基本控制方式、VSC和LCC电压分配方式及各VSC之间的电流分配方式,在得出的约束方程下构建混合级联系统的稳态数学模型;计算各运行方式下VSC的端口直流电压变化范围,并设计各运行方式下调制比范围;基于VSC的PQ运行区间的约束条件,求解VSC的PQ运行区间,并确定档位范围;确定该运行方式下混合级联特高压直流系统的最大运行功率;基于系统的最大运行功率和VSC无功功率,求解混合级联系统的稳态数学模型,获得该系统的稳态运行参数。

Figure 202211307347

The present invention relates to the field of direct current transmission, and provides a method and system for designing the main circuit parameters of a hybrid cascaded UHV DC system, including: determining the operation mode of the hybrid cascaded UHV DC system; determining the basic control mode of VSC and LCC at the receiving end, The voltage distribution mode between VSC and LCC and the current distribution mode between each VSC, construct the steady-state mathematical model of the hybrid cascaded system under the obtained constraint equation; calculate the DC voltage variation range of the VSC port under each operation mode, and design each Modulation ratio range in the operating mode; based on the constraints of the PQ operating range of the VSC, solve the PQ operating range of the VSC and determine the gear range; determine the maximum operating power of the hybrid cascaded UHVDC system in this operating mode; based on the system The maximum operating power and VSC reactive power are used to solve the steady-state mathematical model of the hybrid cascaded system to obtain the steady-state operating parameters of the system.

Figure 202211307347

Description

混合级联特高压直流系统主回路参数设计方法及系统Design method and system for main circuit parameters of hybrid cascaded UHVDC system

技术领域technical field

本发明是关于一种混合级联特高压直流系统主回路参数设计方法及系统,涉及直流输电领域。The invention relates to a method and system for designing parameters of a main circuit of a hybrid cascaded UHV direct current system, and relates to the field of direct current transmission.

背景技术Background technique

为了实现远距离大容量输电和多落点供电,解决受端多馈入短路比下降的难题,可采用混合级联特高压直流输电技术,即常规直流换流器和多个柔性直流换流器级联联接的技术方案,该技术结合了常规直流和柔性直流的优势,可以有效改善受端交流电网的稳定性,且可靠性高,运行方式灵活,具有广泛的应用前景,是构建未来能源互联网的关键技术。In order to realize long-distance large-capacity power transmission and multi-point power supply, and solve the problem of lower short-circuit ratio of multiple infeeds at the receiving end, hybrid cascaded UHVDC transmission technology can be used, that is, conventional DC converters and multiple flexible DC converters The technical solution of cascading connection, which combines the advantages of conventional DC and flexible DC, can effectively improve the stability of the AC power grid at the receiving end, has high reliability, flexible operation mode, and has broad application prospects. key technologies.

混合级联特高压直流系统主回路参数设计的目的是确定直流主设备关键参数,明确各种运行工况下的直流系统稳态运行参数,是混合级联直流系统构建的前提和基础,直接决定系统的暂稳态运行性能。The purpose of the parameter design of the main circuit of the hybrid cascaded UHV DC system is to determine the key parameters of the DC main equipment, and to clarify the steady-state operating parameters of the DC system under various operating conditions. Transient steady-state performance of the system.

现有技术中尚未涉及如何进行混合级联特高压直流输电主回路参数设计,完成混合级联系统的主设备参数的选型和稳态运行特性的获取等问题。The prior art has not involved how to design the main circuit parameters of the hybrid cascade UHVDC transmission, complete the selection of the main equipment parameters of the hybrid cascade system, and obtain the steady-state operating characteristics.

发明内容Contents of the invention

针对上述问题,本发明的目的是提供一种能够确定直流主设备参数和稳态运行参数的混合级联特高压直流系统主回路参数设计方法、系统、设备及介质。In view of the above problems, the object of the present invention is to provide a method, system, equipment and medium for designing the main circuit parameters of the hybrid cascaded UHV DC system capable of determining the parameters of the main DC equipment and the steady-state operating parameters.

为了解决上述技术问题,本发明采用的技术方案为:In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

第一方面,本发明提供的混合级联特高压直流系统主回路参数设计方法,包括:In the first aspect, the method for designing the main circuit parameters of the hybrid cascaded UHV DC system provided by the present invention includes:

确定混合级联特高压直流系统的运行方式;Determine the operation mode of the hybrid cascaded UHVDC system;

确定受端VSC和LCC的基本控制方式、VSC和LCC电压分配方式及各VSC之间的电流分配方式,在得出的约束方程下构建混合级联系统的稳态数学模型;Determine the basic control mode of VSC and LCC at the receiving end, the voltage distribution mode of VSC and LCC, and the current distribution mode between VSCs, and build a steady-state mathematical model of the hybrid cascaded system under the obtained constraint equations;

计算各运行方式下VSC的端口直流电压变化范围,并设计各运行方式下调制比范围;Calculate the DC voltage variation range of the VSC port under each operation mode, and design the modulation ratio range under each operation mode;

基于VSC的PQ运行区间的约束条件,求解VSC的PQ运行区间,并确定柔直换流变需配置的档位范围;Based on the constraints of the PQ operating range of the VSC, the PQ operating range of the VSC is solved, and the gear range that needs to be configured for the soft direct commutation rheology is determined;

确定该运行方式下混合级联特高压直流系统的最大运行功率;Determine the maximum operating power of the hybrid cascaded UHVDC system under this operating mode;

基于系统的最大运行功率和VSC无功功率,求解混合级联系统的稳态数学模型,获得该系统的稳态运行参数。Based on the maximum operating power of the system and VSC reactive power, the steady-state mathematical model of the hybrid cascaded system is solved to obtain the steady-state operating parameters of the system.

进一步地,VSC和LCC的电压分配方式,包括:Further, the voltage distribution method of VSC and LCC includes:

VSC和LCC按照等直流电压的方式分配,则对应约束方程为 U dcvsc= U dclccU dcvscU dclcc分别为VSC和LCC的端口直流电压; VSC and LCC are distributed according to equal DC voltage, and the corresponding constraint equation is U dcvsc = U dclcc , U dcvsc and U dclcc are the port DC voltages of VSC and LCC respectively;

VSC不考虑直流电压的波动,全部由LCC承担线路压降,则对应约束方程为 U dcvsc= U setvscU dcvsc为VSC的端口直流电压, U setvsc为设定值。 The VSC does not consider the fluctuation of the DC voltage, and the line voltage drop is all borne by the LCC. The corresponding constraint equation is U dcvsc = U setvsc , where U dcvsc is the DC voltage of the VSC port, and U setvsc is the set value.

进一步地,各VSC之间的电流分配方式,包括:Further, the current distribution method among the VSCs includes:

各VSC之间按照等电流的方式分配,则约束方程为: I vsc1= I vsc2=... I vscn= I dc/ nI vsc1,... I vscn分别为第1到n个VSC的直流电流, I dc为流入VSC阀组的总电流; The VSCs are distributed according to the method of equal current, then the constraint equation is: I vsc1 = I vsc2 =... I vscn = I dc / n , I vsc1 , ... I vscn are the 1st to nth VSCs respectively DC current, I dc is the total current flowing into the VSC valve group;

各VSC之间独立指定运行功率,则约束方程为: I vsc1= P vsc1/ U setvscI vsc2= P vsc2/ U setvsc... I vscn= I dc- I vsc1- I vsc2... I vsc(n-1)P vsc1P vsc2为VSC1和VSC2的有功功率。 The operating power is independently specified between each VSC, and the constraint equation is: I vsc1 = P vsc1 / U setvsc , I vsc2 = P vsc2 / U setvsc , ... I vscn = I dc - I vsc1 - I vsc2... I vsc(n-1) , P vsc1 and P vsc2 are the active powers of VSC1 and VSC2.

进一步地,各运行方式下调制比范围的确定方法,包括:Further, the method for determining the modulation ratio range in each operation mode includes:

按照线路电阻最大的原则,计算该运行方式下的柔直最小端口电压 U dcinitAccording to the principle of maximum line resistance, calculate the flexible minimum port voltage U dcinit in this operating mode;

遍历各种故障下需要VSC功率转带的工况,计算各工况下VSC功率转带后的端口电压,并确定各工况下的最小端口电压 U dcfinalTraverse the working conditions that require VSC power transfer under various faults, calculate the port voltage after VSC power transfer under each working condition, and determine the minimum port voltage U dcfinal under each working condition;

确定保证VSC输出电压不过调制的最大调制比 M absmax,计算各运行方式下的最大调制比 M maxM max= U dcfinal× M absmax/ U dcinitDetermine the maximum modulation ratio M absmax that ensures that the VSC output voltage is not modulated, and calculate the maximum modulation ratio M max in each operating mode, M max = U dcfinal × M absmax / U dcinit ;

按照能够满足系统谐波要求的电平数设计最小调制比 M minDesign the minimum modulation ratio M min according to the number of levels that can meet the harmonic requirements of the system.

进一步地,求解VSC的PQ运行区间,包括:Further, solve the PQ operating interval of VSC, including:

a、确定VSC的PQ运行区间的限制条件,包括VSC的端口直流电压变化范围、调制比范围、交流电压变化范围、桥臂电流限制、变压器容量限制;a. Determine the limiting conditions of the PQ operating range of the VSC, including the DC voltage range of the VSC port, the modulation ratio range, the AC voltage range, the bridge arm current limit, and the transformer capacity limit;

b、基于约束条件,求解PQ运行区间,PQ运行区间取不同直流电压和交流电压组合下的交集;b. Based on the constraint conditions, solve the PQ operation interval, and the PQ operation interval takes the intersection of different DC voltage and AC voltage combinations;

c、判断功率区间是否满足系统对功率交换的设定要求,如果是则确定PQ运行区间和VCS档位,如果为否,则进入d;c. Determine whether the power range satisfies the system’s setting requirements for power exchange. If so, determine the PQ operation range and VCS gear position. If not, go to d;

d、若发出无功不足或桥臂电流导致功率限制,则增加负档位配置;若吸收无功不足,则增加正档位配置,进入步骤b。d. If the output reactive power is insufficient or the bridge arm current causes power limitation, then increase the negative gear configuration; if the absorbed reactive power is insufficient, increase the positive gear configuration and go to step b.

进一步地,PQ运行区间按照所有档位下的PQ运行区间的并集设计,当单一档位无法满足系统需求时,逐渐增大档位的配置范围以增大PQ运行区间,直到档位配置满足该运行方式下系统对VSC交换能力需求,或增加档位无法再增大VSC和系统的交换功率时为止,即得到该运行方式下的PQ运行区间,各运行方式下求得的档位的并集即为VSC设计的档位。Furthermore, the PQ operating interval is designed according to the union of the PQ operating intervals under all gears. When a single gear cannot meet the system requirements, gradually increase the configuration range of the gear to increase the PQ operating interval until the gear configuration meets In this operation mode, the system needs VSC exchange capacity, or until the exchange power between VSC and system can no longer be increased by increasing the gear position, the PQ operation range in this operation mode is obtained, and the combination of the gear positions obtained in each operation mode The set is the gear designed for VSC.

进一步地,增大档位的配置范围的方法,包括:当桥臂电流限制导致吸收或发出有功功率或无功功率不足时,增加负档位配置,当调制比限制导致吸收无功功率不足时,增加正档位配置;当调制比限制导致发出无功功率不足时,增加负档位配置。Further, the method for increasing the configuration range of gears includes: when the limitation of the bridge arm current causes the absorption or emission of active power or reactive power to be insufficient, increasing the negative gear configuration, when the limitation of the modulation ratio causes the absorption of reactive power to be insufficient , increase the positive gear configuration; when the modulation ratio limitation results in insufficient reactive power, increase the negative gear configuration.

第二方面,本发明提供的一种混合级联特高压直流系统主回路参数设计系统,包括:In the second aspect, the present invention provides a hybrid cascaded UHV DC system main circuit parameter design system, including:

运行方式确定单元,被配置为确定混合级联特高压直流系统的运行方式;an operation mode determination unit configured to determine the operation mode of the hybrid cascaded UHVDC system;

模型构建单元,被配置为确定受端VSC和LCC的基本控制方式、VSC和LCC电压分配方式及各VSC之间的电流分配方式,在设定的约束方程下构建混合级联系统的稳态数学模型;The model construction unit is configured to determine the basic control mode of the VSC and LCC at the receiving end, the voltage distribution mode of the VSC and LCC, and the current distribution mode between each VSC, and construct the steady-state mathematics of the hybrid cascaded system under the set constraint equations Model;

参数确定单元,被配置为计算各运行方式下VSC的端口直流电压变化范围,并设计各运行方式下调制比范围;基于VSC的PQ运行区间的约束条件,求解VSC的PQ运行区间,并确定柔直换流变需配置的档位范围;确定该运行方式下混合级联特高压直流系统的最大运行功率;The parameter determination unit is configured to calculate the variation range of the VSC port DC voltage in each operation mode, and design the modulation ratio range in each operation mode; based on the constraint conditions of the PQ operation interval of the VSC, solve the PQ operation interval of the VSC, and determine the flexible The gear range that needs to be configured for the direct-conversion rheology; determine the maximum operating power of the hybrid cascaded UHV DC system under this operating mode;

模型计算单元,被配置为在基于系统运行功率和VSC无功功率,求解混合级联系统的稳态数学模型,获得该系统的稳态运行参数。The model calculation unit is configured to solve the steady-state mathematical model of the hybrid cascaded system based on the system operating power and the VSC reactive power, and obtain the steady-state operating parameters of the system.

第三方面,本发明提供的一种电子设备,包括计算机程序指令,其中,所述程序指令被处理器执行时用于实现所述的混合级联特高压直流系统主回路参数设计方法。In a third aspect, the present invention provides an electronic device, including computer program instructions, wherein, when the program instructions are executed by a processor, they are used to implement the method for designing the main circuit parameters of the hybrid cascaded UHV DC system.

第四方面,本发明提供的一种计算机可读存储介质,所述计算机可读存储介质上存储有计算机程序指令,其中,所述程序指令被处理器执行时用于实现所述的混合级联特高压直流系统主回路参数设计方法。In a fourth aspect, the present invention provides a computer-readable storage medium, where computer program instructions are stored on the computer-readable storage medium, wherein the program instructions are used to implement the hybrid cascading when executed by a processor Design method of main circuit parameters of UHV DC system.

本发明由于采取以上技术方案,其具有以下特点:The present invention has the following characteristics due to the adoption of the above technical scheme:

1、本发明通过构建混合级联系统的稳态数学模型,在确定的系统运行功率和VSC无功功率内,求解混合级联系统的稳态数学模型,获得该系统的稳态运行参数,因此,本发明提出的主回路设计方案能够保证单个柔性直流换流器退出后系统仍具有满功率运行能力,从而将混合级联系统的强迫能力不可用率从常规直流的0.5%降低至0.375%,有效提高了系统的可靠性。1. The present invention solves the steady-state mathematical model of the hybrid cascade system within the determined system operating power and VSC reactive power by constructing the steady-state mathematical model of the hybrid cascade system, and obtains the steady-state operating parameters of the system. Therefore , the main circuit design scheme proposed by the present invention can ensure that the system still has full power operation capability after the exit of a single flexible DC converter, thereby reducing the forced capacity unavailability rate of the hybrid cascaded system from 0.5% of conventional DC to 0.375%, Effectively improve the reliability of the system.

2、本发明首次提出不同运行方式调制比差别化设计方法,有效地解决混合级联系统由于VSC降压运行能力不足造成的功率转带受限问题。2. For the first time, the present invention proposes a differential design method for modulation ratios in different operating modes, which effectively solves the problem of limited power transfer in hybrid cascaded systems due to insufficient VSC step-down operating capability.

综上,本发明首次提出了混合级联直流系统的主回路设计方案,填补了现有技术空白,可以广泛应用于混合级联特高压直流系统主回路参数中。To sum up, the present invention proposes the design scheme of the main circuit of the hybrid cascaded DC system for the first time, which fills the gap in the prior art, and can be widely applied to the parameters of the main circuit of the hybrid cascaded UHV DC system.

附图说明Description of drawings

通过阅读下文优选实施方式的详细描述,各种其他的优点和益处对于本领域普通技术人员将变得清楚明了。附图仅用于示出优选实施方式的目的,而并不认为是对本发明的限制。在整个附图中,用相同的附图标记表示相同的部件。在附图中:Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiment. The drawings are only for the purpose of illustrating a preferred embodiment and are not to be considered as limiting the invention. Throughout the drawings, the same reference numerals are used to refer to the same parts. In the attached picture:

图1为本发明实施例的混合级联特高压直流主回路参数设计整体流程图。Fig. 1 is an overall flowchart of parameter design of a hybrid cascaded UHV DC main circuit according to an embodiment of the present invention.

图2为本发明实施例的混合级联特高压直流VSC调制比范围设计流程图。Fig. 2 is a flow chart of designing a modulation ratio range of a hybrid cascaded UHVDC VSC according to an embodiment of the present invention.

图3为本发明实施例的混合级联特高压直流VSC运行区间和档位设计流程图。Fig. 3 is a flow chart of the hybrid cascaded UHVDC VSC operating range and gear design according to the embodiment of the present invention.

图4为本发明实施例的混合级联特高压直流系统拓扑结构图。Fig. 4 is a topological structure diagram of a hybrid cascaded UHV DC system according to an embodiment of the present invention.

图5为本发明实施例的电子设备结构图。FIG. 5 is a structural diagram of an electronic device according to an embodiment of the present invention.

具体实施方式Detailed ways

应理解的是,文中使用的术语仅出于描述特定示例实施方式的目的,而无意于进行限制。除非上下文另外明确地指出,否则如文中使用的单数形式“一”、“一个”以及“所述”也可以表示包括复数形式。术语“包括”、“包含”、“含有”以及“具有”是包含性的,并且因此指明所陈述的特征、步骤、操作、元件和/或部件的存在,但并不排除存在或者添加一个或多个其它特征、步骤、操作、元件、部件、和/或它们的组合。文中描述的方法步骤、过程、以及操作不解释为必须要求它们以所描述或说明的特定顺序执行,除非明确指出执行顺序。还应当理解,可以使用另外或者替代的步骤。It should be understood that the terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may also be meant to include the plural forms unless the context clearly dictates otherwise. The terms "comprising", "comprising", "containing" and "having" are inclusive and thus indicate the presence of stated features, steps, operations, elements and/or parts but do not exclude the presence or addition of one or Various other features, steps, operations, elements, components, and/or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order described or illustrated, unless an order of performance is specifically indicated. It should also be understood that additional or alternative steps may be used.

为了便于描述,可以在文中使用空间相对关系术语来描述如图中示出的一个元件或者特征相对于另一元件或者特征的关系,这些相对关系术语例如为“内部”、“外部”、“内侧”、“外侧”、“下面”、“上面”等。这种空间相对关系术语意于包括除图中描绘的方位之外的在使用或者操作中装置的不同方位。For the convenience of description, spatial relative terms may be used herein to describe the relationship of one element or feature as shown in the figures with respect to another element or feature, such as "inner", "outer", "inner". ", "Outside", "Below", "Above", etc. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures.

混合级联特高压直流的主回路参数设计方法和以往常规直流和柔性直流工程存在很大差异,其运行能力受限于常规直流换流阀、柔性直流换流阀、柔性直流运行个数、系统故障穿越能力等多种因素,需要综合系统的暂稳态运行特性得出考虑不同柔直运行个数的上百种方式下的系统运行能力。另外,柔性直流首次呈现直流电压0.7~1pu的大范围波动,其功率运行区间的设计需重点考虑直流电压大范围波动的因素,难以实现单个有功功率-无功功率圆图(PQ圆图)适应各类运行方式。同时,柔性直流的调压开关配置也是主回路参数设计的重点,需和调制比联合设计以保证直流电压的大范围波动下的运行能力。The main circuit parameter design method of hybrid cascaded UHV DC is quite different from the conventional DC and flexible DC projects in the past, and its operating capacity is limited by the number of conventional DC converter valves, flexible DC converter valves, flexible DC Various factors, such as fault ride-through capability, need to integrate the transient steady-state operation characteristics of the system to obtain the system operation capability under hundreds of modes considering different numbers of flexible and direct operations. In addition, the flexible DC presents a large-scale fluctuation of DC voltage of 0.7~1pu for the first time, and the design of its power operation range needs to focus on the factors of large-scale fluctuations of DC voltage, and it is difficult to realize the adaptation of a single active power-reactive power circle diagram (PQ circle diagram). Various modes of operation. At the same time, the configuration of the voltage regulating switch of the flexible DC is also the focus of the parameter design of the main circuit, which needs to be designed in conjunction with the modulation ratio to ensure the operation ability under the large-scale fluctuation of the DC voltage.

基于上述设计思路,本实施例提出的混合级联特高压直流系统主回路参数设计方法,包括:确定混合级联特高压直流系统的运行方式;确定受端VSC和LCC的基本控制方式、VSC和LCC电压分配方式及各VSC之间的电流分配方式,在得出的约束方程下构建混合级联系统的稳态数学模型;计算各运行方式下VSC的端口直流电压变化范围,并设计各运行方式下调制比范围;基于VSC的PQ运行区间的约束条件,求解VSC的PQ运行区间,并确定柔直换流变需配置的档位范围;确定该运行方式下混合级联特高压直流系统的最大运行功率;在确定的系统运行功率和VSC无功功率内,求解混合级联系统的稳态数学模型,获得该系统的稳态运行参数。Based on the above design ideas, the design method for the main circuit parameters of the hybrid cascaded UHV DC system proposed in this embodiment includes: determining the operation mode of the hybrid cascaded UHV DC system; determining the basic control mode of the VSC and LCC at the receiving end, VSC and The LCC voltage distribution method and the current distribution method between each VSC, construct the steady-state mathematical model of the hybrid cascade system under the obtained constraint equation; calculate the DC voltage variation range of the VSC port under each operation mode, and design each operation mode Lower the modulation ratio range; based on the constraints of the PQ operating range of the VSC, solve the PQ operating range of the VSC, and determine the range of gears that need to be configured for the flexible DC converter; determine the maximum Operating power: within the determined system operating power and VSC reactive power, solve the steady-state mathematical model of the hybrid cascade system to obtain the steady-state operating parameters of the system.

下面将参照附图更详细地描述本发明的示例性实施方式。虽然附图中显示了本发明的示例性实施方式,然而应当理解,可以以各种形式实现本发明而不应被这里阐述的实施方式所限制。相反,提供这些实施方式是为了能够更透彻地理解本发明,并且能够将本发明的范围完整的传达给本领域的技术人员。Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided for more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

如图1所示,本实施例提供的混合级联特高压直流系统主回路参数设计方法,包括:As shown in Figure 1, the method for designing the main circuit parameters of the hybrid cascaded UHV DC system provided in this embodiment includes:

S1、根据系统需求和混合级联特高压直流的拓扑特点,确定混合级联特高压直流系统的运行方式。S1. Determine the operation mode of the hybrid cascaded UHV DC system according to the system requirements and the topology characteristics of the hybrid cascaded UHV DC system.

本实施例中,将混合级联特高压直流的运行方式进行分类,首先按照常规特高压直流的运行方式分类方法,考虑双极/单极大地/单极金属、双阀组/单阀组以及阀组的组合,其中,VSC(电压源换流器)阀组按照一体化考虑方法为45种,进一步考虑正、负极不同的VSC运行个数和运行的VSC阀,可以组合确定运行每小类下包含的运行方式。In this embodiment, the operation mode of hybrid cascaded UHV DC is classified. Firstly, according to the classification method of conventional UHV DC operation mode, bipolar/unipolar ground/unipolar metal, double valve group/single valve group and The combination of valve groups, among them, there are 45 types of VSC (voltage source converter) valve groups according to the integrated consideration method, further considering the number of VSC operating with different positive and negative poles and the operating VSC valves, it can be combined to determine the operation of each sub-category Included below are the modes of operation.

进一步地,由于VSC和LCC(电网换相换流器)潮流翻转时分别为电压不能翻转和电流不能翻转,因此由混合级联的拓扑特性决定了混合级联特高压直流不考虑功率反送。根据系统需要配置多个VSC之间的功率互济方式,即其中部分VSC运行于整流状态,部分VSC运行于逆变状态,逆变运行的VSC接收送端LCC和整流状态的VSC的功率。降压运行通过转为半压运行实现,避免通过常直和柔直不对称降压实现双阀组降压运行,一方面降低分接开关的配置和动作频次,大大降低了分接开关频繁动作造成的设备安全风险,一方面避免不对称降压时LCC退出造成的功率转带严重受限问题。Furthermore, since VSC and LCC (Line Commutated Converter) reverse the power flow, the voltage cannot be reversed and the current cannot be reversed respectively. Therefore, the topology characteristics of the hybrid cascade determines that the hybrid cascade UHV DC does not consider power feedback. Configure the power mutual aid mode between multiple VSCs according to system requirements, that is, some VSCs run in the rectification state, and some VSCs run in the inverter state. Step-down operation is realized by switching to half-pressure operation, avoiding double-valve group step-down operation through constant straight and soft straight asymmetric step-down. On the one hand, the configuration and action frequency of the tap changer are reduced, and the frequent action of the tap changer is greatly reduced. On the one hand, it avoids the severe limitation of the power transfer belt caused by the withdrawal of the LCC during the asymmetric step-down.

S2、根据混合级联的拓扑结构,确定受端VSC和LCC的基本控制方式、VSC和LCC电压分配方式及各VSC之间的电流分配方式,并列出约束方程,构建混合级联系统的稳态数学模型。S2. According to the topology structure of the hybrid cascade, determine the basic control mode of the VSC and LCC at the receiving end, the voltage distribution mode of the VSC and LCC, and the current distribution mode between each VSC, and list the constraint equations to build a stable hybrid cascade system. state mathematical model.

本实施例中,VSC和LCC的电压分配方式包括两种:In this embodiment, the voltage distribution methods of VSC and LCC include two types:

第一种方式:VSC和LCC按照等直流电压的方式分配,则对应约束方程为 U dcvsc= U dclccU dcvscU dclcc分别为VSC和LCC的端口直流电压; The first way: VSC and LCC are distributed according to equal DC voltage, then the corresponding constraint equation is U dcvsc = U dclcc , U dcvsc and U dclcc are the port DC voltages of VSC and LCC respectively;

第二种方式:VSC不考虑直流电压的波动,全部由LCC承担线路压降,则对应约束方程为 U dcvsc= U setvscU dcvsc为VSC的端口直流电压, U setvsc为设定值。 The second method: VSC does not consider the fluctuation of the DC voltage, and all the line voltage drops are borne by the LCC. The corresponding constraint equation is U dcvsc = U setvsc , U dcvsc is the DC voltage of the VSC port, and U setvsc is the set value.

其中,第一种方式下,VSC的端口电压波动幅度较大,VSC需配置较多档位。第二种方式下,LCC的端口电压波动为原来的2倍,LCC档位配置多,单极金属返回等电压降较大的方式下,档位调节到极限时,需增大关断角,换流阀无功增加,而且由于LCC和VSC电压不对称运行,若LCC故障退出,送、受端电压压差巨大,功率转带能力将严重受限。按照对系统友好的原则,VSC档位配置不受限时,采用第一种方式。Among them, in the first method, the port voltage of the VSC fluctuates greatly, and the VSC needs to be configured with more gears. In the second method, the port voltage fluctuation of the LCC is twice the original, and the LCC gear configuration is large, and the voltage drop of the unipolar metal return is large. When the gear is adjusted to the limit, the cut-off angle needs to be increased. The reactive power of the converter valve increases, and because the LCC and VSC voltages operate asymmetrically, if the LCC fails and exits, the voltage difference between the sending and receiving terminals will be huge, and the power transfer capability will be severely limited. According to the principle of being friendly to the system, when the VSC gear configuration is not limited, the first method is adopted.

本实施例中,各VSC之间的电流分配方式包括两种:In this embodiment, the current distribution methods among the VSCs include two types:

第一种方式为:各VSC之间按照等电流的方式分配,则约束方程为: I vsc1= I vsc2=... I vscn= I dc/ nI vsc1,... I vscn分别为第1到n个VSC的直流电流, I dc为流入VSC阀组的总电流; The first method is: all VSCs are distributed according to equal current, then the constraint equation is: I vsc1 = I vsc2 =... I vscn = I dc / n , I vsc1 , ... I vscn are respectively The direct current of 1 to n VSCs, I dc is the total current flowing into the VSC valve group;

第二种方式:各VSC之间独立指定运行功率,则约束方程为: I vsc1= P vsc1/ U setvscI vsc2= P vsc2/ U setvsc... I vscn= I dc- I vsc1- I vsc2... I vsc(n-1)P vsc1P vsc2为VSC1和VSC2的有功功率。 The second method: independently specify the operating power between each VSC, then the constraint equation is: I vsc1 = P vsc1 / U setvsc , I vsc2 = P vsc2 / U setvsc , ... I vscn = I dc - I vsc1 - I vsc2... I vsc(n-1) , P vsc1 and P vsc2 are the active powers of VSC1 and VSC2.

S3、按照最大线路电阻、最大运行电流和最小线路电阻、最小运行电流求解出各运行方式下VSC的端口直流电压变化范围,计算各运行方式下满足各种转带功率需要的VSC电压速降需求以及设计各运行方式下的调制比范围。S3. According to the maximum line resistance, maximum operating current, minimum line resistance, and minimum operating current, the DC voltage variation range of the VSC port is solved in each operating mode, and the VSC voltage drop requirements for various transfer power requirements are calculated in each operating mode. And design the modulation ratio range under each operation mode.

本实施例中,求解出各运行方式下VSC的端口直流电压变化范围为[ U dcminU dcmax]。 In this embodiment, the variation range of the DC voltage at the port of the VSC in each operating mode is calculated to be [ U dcmin , U dcmax ].

本实施例中,如图2所示,各运行方式下的调制比范围的确定方法为:In this embodiment, as shown in Figure 2, the method for determining the modulation ratio range under each operating mode is:

按照线路电阻最大的原则,计算该运行方式下的柔直最小端口电压 U dcinitAccording to the principle of maximum line resistance, calculate the flexible minimum port voltage U dcinit in this operating mode;

遍历各种故障下需要VSC功率转带的工况,计算各工况下VSC功率转带后的端口电压,并确定各工况下的最小端口电压 U dcfinalTraverse the working conditions that require VSC power transfer under various faults, calculate the port voltage after VSC power transfer under each working condition, and determine the minimum port voltage U dcfinal under each working condition;

确定保证VSC输出电压不过调制的最大调制比 M absmax,计算各运行方式下的最大调制比 M maxM max= U dcfinal× M absmax/ U dcinit,其中, U dcfinal为转带功率造成压降最大的工况下的故障后直流电压, U dcinit为转带功率造成压降最大的工况下的故障前直流电压, M absmax为保证柔性直流输出电压不过调制的最大调制比,若采用三次谐波注入,一般取1.05~1.15之间。 Determine the maximum modulation ratio M absmax that ensures that the VSC output voltage is not modulated, and calculate the maximum modulation ratio M max in each operating mode, M max = U dcfinal × M absmax / U dcinit , where U dcfinal is the maximum voltage drop caused by the transfer power The post-fault DC voltage under the working condition, U dcinit is the pre-fault DC voltage under the working condition where the transfer power causes the largest voltage drop, and M absmax is the maximum modulation ratio to ensure that the flexible DC output voltage is not modulated. If the third harmonic Injection, generally between 1.05 and 1.15.

按照能够满足系统谐波要求的电平数设计最小调制比 M min,一般取0.7~0.85。 Design the minimum modulation ratio M min according to the number of levels that can meet the harmonic requirements of the system, generally 0.7~0.85.

进一步地,各运行方式可分别设计不同的调制比范围,为了简化控制保护策略,可将45种运行方式按照功率转带所需的调制比范围进一步分为2~3类,每类按照此类所有运行方式满足功率转带要求的调制比范围的交集确定统一的调制比范围。Furthermore, different modulation ratio ranges can be designed for each operation mode. In order to simplify the control and protection strategy, the 45 operation modes can be further divided into 2~3 categories according to the modulation ratio range required for power transfer. The intersection of the modulation ratio ranges of all operating modes satisfying the power transfer band requirement determines a unified modulation ratio range.

S4、基于确定的LCC和VSC的端口直流电压、直流电流,按照LCC和VSC的主设备参数选取方法,分别独立计算LCC和VSC的换流变额定电压、额定容量、短路阻抗等设备参数。S4. Based on the determined port DC voltage and DC current of LCC and VSC, according to the selection method of the main equipment parameters of LCC and VSC, independently calculate the equipment parameters such as rated voltage, rated capacity and short-circuit impedance of the converter transformer of LCC and VSC respectively.

S5、基于VSC的PQ运行区间的约束条件,求解VSC的PQ运行区间,并确定柔直换流变需配置的档位范围;S5. Based on the constraints of the PQ operating interval of the VSC, solve the PQ operating interval of the VSC, and determine the range of gears that need to be configured for the soft direct commutation rheology;

本实施例中,如图3所示,求解VSC的PQ运行区间,包括:In this embodiment, as shown in Figure 3, the PQ operating interval of the VSC is solved, including:

S51、确定VSC的PQ运行区间的限制条件,包括VSC的端口直流电压变化范围、调制比范围、交流电压变化范围、桥臂电流限制、变压器容量限制等约束条件;S51. Determine the constraints of the PQ operating range of the VSC, including constraints such as the VSC port DC voltage variation range, modulation ratio range, AC voltage variation range, bridge arm current limitation, and transformer capacity limitation;

S52、基于约束条件,求解PQ运行区间,PQ运行区间取不同直流电压和交流电压组合下的交集;S52. Solve the PQ operation interval based on the constraint conditions, and the PQ operation interval takes the intersection of different DC voltage and AC voltage combinations;

S53、判断功率区间是否满足系统对功率交换的设定要求,如果是则确定PQ运行区间和VCS档位,如果为否,则进入S54;S53. Determine whether the power range meets the system's setting requirements for power exchange, if yes, determine the PQ operation range and the VCS gear, if no, then enter S54;

S54、若发出无功不足或桥臂电流导致功率限制,则增加负档位配置;若吸收无功不足,则增加正档位配置,进入步骤S52。S54. If the reactive power generated is insufficient or the bridge arm current causes power limitation, increase the negative gear configuration; if the absorbed reactive power is insufficient, increase the positive gear configuration, and enter step S52.

进一步地,PQ运行区间按照所有档位下的PQ运行区间的并集设计,当单一档位无法满足系统需求时,逐渐增大档位的配置范围以增大PQ运行区间。直到档位配置满足该运行方式下系统对VSC交换能力需求,或增加档位无法再增大VSC和系统的交换功率时为止,即得到该运行方式下的PQ运行区间,各运行方式下求得的档位的并集即为VSC设计的档位。Furthermore, the PQ operating interval is designed according to the union of the PQ operating intervals under all gears. When a single gear cannot meet the system requirements, the configuration range of the gear is gradually increased to increase the PQ operating interval. Until the gear configuration meets the requirements of the system for VSC switching capacity in this operating mode, or the switching power between the VSC and the system can no longer be increased by increasing the gear, the PQ operating range in this operating mode can be obtained, and obtained in each operating mode The union of the gears is the gear designed by VSC.

进一步地,各运行方式可分别设计不同的PQ运行区间,为了简化控制保护策略,可将45种运行方式进一步分为2~3类,每类给出满足该类内所有运行方式的统一的PQ运行区间,各统一的PQ运行区间为该类所有运行方式PQ运行区间的交集。Furthermore, different PQ operation intervals can be designed for each operation mode. In order to simplify the control and protection strategy, the 45 operation modes can be further divided into 2~3 categories, and each category provides a unified PQ that satisfies all the operation modes in the category. Operation interval, each unified PQ operation interval is the intersection of PQ operation intervals of all operation modes of this type.

进一步地,增大档位的配置范围的方法是:当桥臂电流限制导致吸收或发出有功功率或无功功率不足时,增加负档位配置,当调制比限制导致吸收无功功率不足时,增加正档位配置;当调制比限制导致发出无功功率不足时,增加负档位配置。Further, the method of increasing the configuration range of gears is: when the limit of the bridge arm current causes insufficient active power or reactive power to be absorbed or emitted, increase the negative gear configuration; when the limitation of the modulation ratio results in insufficient absorbed reactive power, Add a positive gear configuration; when the modulation ratio limitation results in insufficient reactive power, add a negative gear configuration.

S6、根据PQ运行区间确定VSC对应的最大运行功率 P vscmax1,计算该最大运行功率下对应的整流侧最大运行功率,即系统最大运行功率 P max1,计算时按照最小线路电阻。 S6. Determine the maximum operating power P vscmax1 corresponding to the VSC according to the PQ operating interval, and calculate the maximum operating power of the rectification side corresponding to the maximum operating power, that is, the maximum operating power P max1 of the system, and calculate according to the minimum line resistance.

S7、基于PSCAD/EMTDC软件建立混合级联系统的电磁暂态仿真模型,仿真扫描计算各运行方式下满足交流故障穿越要求的系统最大运行功率为 P max2,计算时,先将系统功率设置为系统额定值,仿真计算交流系统故障时换流阀的过压和可控自恢复消能装置的能量,若不越限,则最大功率 P max2即系统的额定功率,否则逐步降低 P max2,直到能够满足换流阀过压和消能装置能量的要求为止。 S7. Based on the PSCAD/EMTDC software, establish the electromagnetic transient simulation model of the hybrid cascaded system. The maximum operating power of the system that meets the requirements of AC fault ride-through in each operating mode is simulated and scanned to be P max2 . When calculating, the system power is first set to Rated value, simulation calculation of the overvoltage of the converter valve and the energy of the controllable self-restoring energy dissipation device when the AC system fails, if the limit is not exceeded, the maximum power P max2 is the rated power of the system, otherwise, P max2 is gradually reduced until it can Until the overpressure of the converter valve and the energy requirements of the energy dissipation device are met.

本实施例中,在PSCAD/EMTDC软件建立详细的可控自恢复消能装置模型,满足交流系统故障穿越要求的原则是:模块电压不超过换流阀解锁运行的过压保护定值,桥臂电流不达到保护定值,消能装置能量在其最大设计能量之内。其中,消能装置避雷器为大特性和小特性时需分别开展仿真。In this embodiment, a detailed controllable self-restoring energy dissipation device model is established in PSCAD/EMTDC software, and the principle to meet the fault ride-through requirements of the AC system is: the voltage of the module does not exceed the overvoltage protection setting value for the unlocking operation of the converter valve, and the bridge arm If the current does not reach the protection setting value, the energy of the energy dissipation device is within its maximum design energy. Among them, the surge arrester of the energy dissipation device needs to be simulated separately when it has a large characteristic and a small characteristic.

S8、确定该运行方式下系统的最大运行功率 P max=max( P max1P max2)。若最大运行功率小于系统额定运行功率,需做功率限制处理,或者采用更大通流能力的IGBT器件、增加模块数、增大模块电容等方法进一步增大 P max1P max2,直到满足系统功率要求。 S8. Determine the maximum operating power P max =max( P max1 , P max2 ) of the system in this operating mode. If the maximum operating power is less than the rated operating power of the system, power limit processing is required, or methods such as using IGBT devices with greater current capacity, increasing the number of modules, and increasing the module capacitance to further increase P max1 and P max2 until the system power requirements are met .

S9、在最终确定的系统运行功率和VSC无功功率内,求解构建的混合级联系统的稳态数学模型,进行各运行方式下运行功率从0.1pu~1pu的运行特性计算,形成系统的稳态运行参数。S9. Within the final determined system operating power and VSC reactive power, solve the constructed steady-state mathematical model of the hybrid cascaded system, and calculate the operating characteristics of the operating power from 0.1pu to 1pu in each operating mode to form a stable system. State running parameters.

本实施例中,在各运行方式下,采用牛顿-拉夫逊法求解稳态数学模型。In this embodiment, under each operating mode, the Newton-Raphson method is used to solve the steady-state mathematical model.

下面通过具体实施例详细说明本发明提供的混合级联特高压直流系统主回路参数设计方法的应用。The application of the method for designing the parameters of the main circuit of the hybrid cascaded UHV DC system provided by the present invention will be described in detail below through specific embodiments.

如图4所示,混合级联特高压直流输电系统送端采用常规特高压直流拓扑,每极均由2个十二脉动常规直流换流器级联构成;受端采用混合级联特高压直流拓扑,每极均由高压端(即800kV~400kV)十二脉动常规直流换流器和低压端(400kV~中性线)多个(图中所示为3个)并联的柔性直流换流器级联而成,柔性直流换流器采用半桥型模块化多电平换流器,受端常规直流换流器和每个柔性直流换流器均馈入不同的交流母线。As shown in Figure 4, the sending end of the hybrid cascaded UHVDC transmission system adopts a conventional UHV DC topology, and each pole is composed of two twelve-pulse conventional DC converters cascaded; the receiving end adopts a hybrid cascaded UHVDC topology. Topology, each pole consists of a high-voltage side (ie 800kV~400kV) twelve-pulse conventional DC converter and a low-voltage side (400kV~neutral line) multiple (3 shown in the figure) parallel-connected flexible DC converters It is formed by cascading, and the flexible DC converter adopts a half-bridge modular multilevel converter, and the conventional DC converter at the receiving end and each flexible DC converter are fed into different AC buses.

下面以±800kV/8000MW、受端由单个LCC和3个VSC混合级联特高压直流输电系统的主回路参数设计为具体实施例,对本发明进一步详细说明。In the following, the present invention will be further described in detail by taking the design of the main circuit parameters of the ±800kV/8000MW UHVDC power transmission system mixed cascaded with a single LCC and 3 VSCs at the receiving end as a specific example.

1、首先根据系统需求和混合级联特高压直流的拓扑特点,确定混合级联特高压直流系统的运行方式。1. First, determine the operation mode of the hybrid cascaded UHVDC system according to the system requirements and the topology characteristics of the hybrid cascaded UHVDC system.

具体地,将混合级联特高压直流的运行方式按照常规特高压直流分为7大类、45小类,考虑正、负极不同的VSC运行个数为1个、2个或3个,组合确定运行每小类下包含的运行方式共计621种。Specifically, the operation mode of the hybrid cascaded UHVDC is divided into 7 categories and 45 subcategories according to the conventional UHVDC. Considering that the number of VSCs with different positive and negative poles is 1, 2 or 3, the combination is determined. There are a total of 621 operation modes included in each sub-category of operation.

2、根据混合级联的拓扑结构,确定受端VSC和LCC的基本控制方式、电压分配方式及电流分配方式,构建混合级联系统的稳态数学模型。2. According to the topology structure of the hybrid cascade, determine the basic control mode, voltage distribution mode and current distribution mode of the VSC and LCC at the receiving end, and build a steady-state mathematical model of the hybrid cascade system.

具体地,送端LCC采用定直流电流控制,受端LCC采用定直流电压控制,受端3个VSC中,1个采用定直流电压控制,2个采用定有功功率控制。Specifically, the LCC at the sending end adopts constant DC current control, and the LCC at the receiving end adopts constant DC voltage control. Among the three VSCs at the receiving end, one is controlled by constant DC voltage, and the other two are controlled by constant active power.

确定VSC和LCC的电压分配方式,例如采用高低压电压均衡的方式。Determine the voltage distribution method of VSC and LCC, for example, adopt the method of balancing high and low voltage voltages.

确定VSC之间的电流分配方式,例如按照3个VSC电流均分。Determine the current distribution mode among the VSCs, for example, divide the currents equally among the three VSCs.

进而得出约束方程为: I dc= I setU dcvsc= U dclcc= U setI vsc1= I vsc2= I vsc3,最后构建混合级联系统的稳态数学模型: Then the constraint equations are: I dc = I set , U dcvsc = U dclcc = U set , I vsc1 = I vsc2 = I vsc3 , and finally build a steady-state mathematical model of the hybrid cascaded system:

式中, U dRU dI为送端和受端LCC单个换流器的端间电压, R eq为直流回路的等效电阻, U di0RU di0I分别为整流侧和逆变侧每个6脉动换流器的理想空载直流电压, U di0NRU di0NI分别为整流侧和逆变侧每个6脉动换流器的理想空载直流电压额定值, α为整流侧触发角,γ为逆变侧关断角, d xRd xI分别为整流侧和逆变侧的电感压降标么值, d rRd rI分别为整流侧和逆变侧的电阻压降标么值, I dN为直流电流额定值, U T为一个6脉动换流器的固有压降, P vscnQ vscn为第n个VSC的有功功率和无功功率, M n为第n个VSC的调制比, U snU cn为第n个VSC的交流母线电压和换流器输出电压, X为VSC的交流母线和换流器之间的等值电抗, δn为第n个VSC的交流母线电压和换流器输出电压的相角差。 In the formula, UdR and UdI are the terminal voltage of a single LCC converter at the sending end and the receiving end, R eq is the equivalent resistance of the DC circuit, U di0R and U di0I are the rectification side and the inverter side each 6 The ideal no-load DC voltage of the pulse converter, U di0NR and U di0NI are the ideal no-load DC voltage ratings of each 6-pulse converter on the rectification side and the inverter side, respectively, α is the firing angle of the rectification side, and γ is the inverse The turn-off angle of the variable side, d xR and d xI are the nominal value of the inductance voltage drop on the rectifier side and the inverter side respectively, d rR and d rI are the standard value of the resistance voltage drop on the rectifier side and the inverter side respectively, I dN is the DC current rating, U T is the inherent voltage drop of a 6-pulse converter, P vscn and Q vscn are the active power and reactive power of the nth VSC, M n is the modulation ratio of the nth VSC, U sn and U cn are the AC bus voltage of the nth VSC and the output voltage of the converter, X is the equivalent reactance between the AC bus of the VSC and the converter, δ n is the AC bus voltage and the converter output voltage of the nth VSC The phase angle difference of the converter output voltage.

3、分别按照最大线路电阻、最大运行电流和最小线路电阻、最小运行电流求解出各运行方式下VSC的端口直流电压变化范围,并设计各运行方式下的最大调制比 M max,最小调制比 M min3. According to the maximum line resistance, maximum operating current, minimum line resistance, and minimum operating current, solve the DC voltage variation range of the VSC port in each operating mode, and design the maximum modulation ratio M max and the minimum modulation ratio M in each operating mode min .

本实施例中,按照额定电阻为10Ω,最大电阻为12Ω,最小线路电阻为8Ω,最大运行电流为5kA,最小短路电流为0.5kA。以单极金属返回运行为例,该方式下VSC的端口电压范围为[340,396]kV,该方式下,在各种转带工况下,柔直可能最大压降的工况是单阀组退出,此时VSC电压需由340kV降低至280kV。考虑保证不过调制的最大调制比为1.05,则进一步该方式下的最大调制比确定为0.86。In this embodiment, the rated resistance is 10Ω, the maximum resistance is 12Ω, the minimum line resistance is 8Ω, the maximum operating current is 5kA, and the minimum short-circuit current is 0.5kA. Taking the unipolar metal return operation as an example, the port voltage range of the VSC in this mode is [340, 396]kV. In this mode, under various rotating conditions, the working condition with the largest possible pressure drop is the single valve When the group exits, the VSC voltage needs to be reduced from 340kV to 280kV. Considering that the maximum modulation ratio that cannot be guaranteed to be modulated is 1.05, the maximum modulation ratio in this mode is further determined to be 0.86.

4、基于确定的LCC和VSC的端口直流电压、直流电流,按照LCC和VSC的主设备参数选取方法,分别独立计算LCC和VSC的换流变额定电压、额定容量、短路阻抗等设备参数。4. Based on the determined port DC voltage and DC current of LCC and VSC, according to the selection method of main equipment parameters of LCC and VSC, independently calculate the equipment parameters such as rated voltage, rated capacity and short-circuit impedance of LCC and VSC respectively.

本实施例中,额定工况下,送端LCC的端口直流电压为400kV,直流电流为5kA;受端LCC的端口直流电压为375kV,直流电流为5kA;受端VSC的端口直流电压为375kV,直流电流为5kA,按照传统方法计算出LCC和VSC的基本设备参数。In this embodiment, under rated working conditions, the port DC voltage of the sending end LCC is 400kV, and the DC current is 5kA; the port DC voltage of the receiving end LCC is 375kV, and the DC current is 5kA; the port DC voltage of the receiving end VSC is 375kV, The DC current is 5kA, and the basic equipment parameters of LCC and VSC are calculated according to the traditional method.

5、基于VSC的端口直流电压变化范围、调制比范围、交流电压变化范围、桥臂电流限制、变压器容量限制等约束,并求解VSC的PQ运行区间。5. Based on the constraints of VSC port DC voltage variation range, modulation ratio range, AC voltage variation range, bridge arm current limit, transformer capacity limit, etc., and solve the PQ operating range of VSC.

PQ运行区间按照所有档位下的PQ运行区间的并集设计,当单一档位无法满足系统需求时,逐渐增大档位的配置范围以增大PQ运行区间。直到档位配置满足该运行方式下系统对VSC交换能力需求,或增加档位无法再增大VSC和系统的交换功率时为止,即得到该运行方式下的PQ运行区间,各运行方式下求得的档位的并集即为VSC设计的档位。The PQ operating interval is designed according to the union of the PQ operating intervals under all gears. When a single gear cannot meet the system requirements, gradually increase the configuration range of the gear to increase the PQ operating interval. Until the gear configuration meets the requirements of the system for VSC switching capacity in this operating mode, or the switching power between the VSC and the system can no longer be increased by increasing the gear, the PQ operating range in this operating mode can be obtained, and obtained in each operating mode The union of the gears is the gear designed by VSC.

确定VSC的最大运行功率为:VSC阀组所在极为全压运行且电流与另一极电流对称时,单个VSC(单极)的最大运行功率为1000MW;VSC阀组所在极为全压运行且与另一极电流不对称或VSC阀组所在极为半压运行且与另一极电流对称时,单个VSC(单极)的最大运行功率为960MW;VSC阀组所在极为半压运行且与另一极不对称时,单个VSC(单极)的最大运行功率为800MW。VSC应设计的档位为+24,-6档。The maximum operating power of the VSC is determined as follows: when the VSC valve group operates at full pressure and the current is symmetrical to the current of the other pole, the maximum operating power of a single VSC (unipolar) is 1000MW; the VSC valve group operates at extremely full pressure and is connected to another pole. When the current in one pole is asymmetrical or the VSC valve group operates at half pressure and is symmetrical with the current of the other pole, the maximum operating power of a single VSC (unipolar) is 960MW; When symmetrical, the maximum operating power of a single VSC (unipolar) is 800MW. The gears that VSC should design are +24, -6 gears.

6、然后根据PQ运行区间确定的VSC对应的最大运行功率 P vscmax1,计算该最大运行功率下对应的整流侧最大运行功率,即系统最大运行功率 P max1,计算时按照最小线路电阻。 6. Then, according to the maximum operating power P vscmax1 corresponding to the VSC determined in the PQ operating interval, calculate the maximum operating power of the rectification side corresponding to the maximum operating power, that is, the maximum operating power P max1 of the system, and calculate according to the minimum line resistance.

本实施例中,当VSC运行个数为3个时,系统最大运行功率和常规直流相同;当VSC运行个数为2个时,大多数方式系统最大运行功率均和常规直流相同,仅一种情况受限,即含VSC的单极半压运行,此时系统最大运行功率为1730MW。In this embodiment, when the number of VSCs is 3, the maximum operating power of the system is the same as that of conventional DC; when the number of VSCs is 2, the maximum operating power of the system in most modes is the same as that of conventional DC, and only one The situation is limited, that is, unipolar half-voltage operation with VSC, and the maximum operating power of the system is 1730MW at this time.

7、建立混合级联系统的PSCAD仿真模型,仿真扫描计算各运行方式下满足交流故障穿越要求的系统最大运行功率为 P max2,该实施例中,通过优化配置消能装置的参数, P max2和常规直流工程一致。 7. Establish the PSCAD simulation model of the hybrid cascaded system, and simulate and scan the maximum operating power of the system that meets the AC fault ride-through requirements under each operating mode to be Pmax2 . In this embodiment, by optimizing the parameters of the energy dissipation device, Pmax2 and Regular DC works the same.

8、确定该运行方式下系统的最大运行功率 P max=max( P max1P max2)。对于受限的单极半压运行且VSC运行个数为2的方式,限制最大运行功率。 8. Determine the maximum operating power P max =max( P max1 , P max2 ) of the system in this operating mode. For the limited unipolar half-voltage operation and the number of VSCs is 2, the maximum operating power is limited.

9、在最终确定的系统运行功率和VSC无功功率内,求解构建的混合级联系统的稳态数学模型,进行各运行方式下运行功率从0.1pu~1pu的运行特性计算,形成系统的稳态运行参数。其中,表1和表2所示为该实施例中双极全压1+3运行方式下的稳态运行参数表。9. Within the final determined system operating power and VSC reactive power, solve the constructed steady-state mathematical model of the hybrid cascaded system, and calculate the operating characteristics of the operating power from 0.1pu to 1pu in each operating mode to form a stable system. State running parameters. Among them, Table 1 and Table 2 show the steady-state operation parameter table under the bipolar full-pressure 1+3 operation mode in this embodiment.

表1 常直部分Table 1 Normal straight part

表2 柔直部分Table 2 Soft straight part

实施例二:上述实施例一提供了混合级联特高压直流系统主回路参数设计方法,与之相对应地,本实施例提供一种混合级联特高压直流系统主回路参数设计系统。本实施例提供的系统可以实施实施例一的混合级联特高压直流系统主回路参数设计方法,该系统可以通过软件、硬件或软硬结合的方式来实现。为了描述的方便,描述本实施例时以功能分为各种单元分别描述。当然,在实施时可以把各单元的功能在同一个或多个软件和/或硬件中实现。例如,该系统可以包括集成的或分开的功能模块或功能单元来执行实施例一各方法中的对应步骤。由于本实施例的系统基本相似于方法实施例,所以本实施例描述过程比较简单,相关之处可以参见实施例一的部分说明即可,本发明提供的混合级联特高压直流系统主回路参数设计系统的实施例仅仅是示意性的。Embodiment 2: The first embodiment above provides a method for designing the parameters of the main circuit of the hybrid cascaded UHV DC system. Correspondingly, this embodiment provides a system for designing the parameters of the main circuit of the hybrid cascaded UHV DC system. The system provided in this embodiment can implement the method for designing the parameters of the main circuit of the hybrid cascaded UHV DC system in Embodiment 1, and the system can be realized by software, hardware, or a combination of software and hardware. For the convenience of description, when describing this embodiment, functions are divided into various units and described separately. Of course, the functions of each unit can be realized in one or more pieces of software and/or hardware during implementation. For example, the system may include integrated or separate functional modules or functional units to execute corresponding steps in the methods of the first embodiment. Since the system of this embodiment is basically similar to the method embodiment, the description process of this embodiment is relatively simple. For relevant points, please refer to the part of the description of Embodiment 1. The parameters of the main circuit of the hybrid cascaded UHV DC system provided by the present invention The embodiments of the design system are illustrative only.

具体地,本实施例提供的混合级联特高压直流系统主回路参数设计系统,包括:Specifically, the hybrid cascaded UHV DC system main circuit parameter design system provided in this embodiment includes:

运行方式确定单元,被配置为确定混合级联特高压直流系统的运行方式;an operation mode determination unit configured to determine the operation mode of the hybrid cascaded UHVDC system;

模型构建单元,被配置为确定受端VSC和LCC的基本控制方式、VSC和LCC电压分配方式及各VSC之间的电流分配方式,在设定的约束方程下构建混合级联系统的稳态数学模型;The model construction unit is configured to determine the basic control mode of the VSC and LCC at the receiving end, the voltage distribution mode of the VSC and LCC, and the current distribution mode between each VSC, and construct the steady-state mathematics of the hybrid cascaded system under the set constraint equations Model;

参数确定单元,被配置为计算各运行方式下VSC的端口直流电压变化范围,并设计各运行方式下调制比范围;基于VSC的PQ运行区间的约束条件,求解VSC的PQ运行区间,并确定柔直换流变需配置的档位范围;确定该运行方式下混合级联特高压直流系统的最大运行功率;The parameter determination unit is configured to calculate the variation range of the VSC port DC voltage in each operation mode, and design the modulation ratio range in each operation mode; based on the constraint conditions of the PQ operation interval of the VSC, solve the PQ operation interval of the VSC, and determine the flexible The gear range that needs to be configured for the direct-conversion rheology; determine the maximum operating power of the hybrid cascaded UHV DC system under this operating mode;

模型计算单元,被配置为在基于系统运行功率和VSC无功功率,求解混合级联系统的稳态数学模型,获得该系统的稳态运行参数。The model calculation unit is configured to solve the steady-state mathematical model of the hybrid cascaded system based on the system operating power and the VSC reactive power, and obtain the steady-state operating parameters of the system.

实施例三:本实施例提供一种与本实施例一所提供的混合级联特高压直流系统主回路参数设计方法对应的电子设备,电子设备可以是用于客户端的电子设备,例如手机、笔记本电脑、平板电脑、台式机电脑等,以执行实施例一的方法。Embodiment 3: This embodiment provides an electronic device corresponding to the method for designing the main circuit parameters of the hybrid cascaded UHV DC system provided in Embodiment 1. The electronic device can be an electronic device for the client, such as a mobile phone, a notebook Computers, tablet computers, desktop computers, etc., to execute the method of Embodiment 1.

如图5所示,电子设备包括处理器、存储器、通信接口和总线,处理器、存储器和通信接口通过总线连接,以完成相互间的通信。总线可以是工业标准体系结构(ISA,IndustryStandard Architecture)总线,外部设备互连(PCI,PeripheralComponent)总线或扩展工业标准体系结构(EISA,Extended Industry Standard Component)总线等等。存储器中存储有可在所述处理器上运行的计算机程序,所述处理器运行所述计算机程序时执行本实施例一所提供的混合级联特高压直流系统主回路参数设计方法。本领域技术人员可以理解,图5中示出的结构,仅仅是与本申请方案相关的部分结构的框图,并不构成对本申请方案所应用于其上的计算设备的限定,具体的计算设备可以包括比图中所示更多或更少的部件,或者组合某些部件,或者具有不同的部件布置。As shown in FIG. 5 , the electronic device includes a processor, a memory, a communication interface and a bus, and the processor, the memory and the communication interface are connected through the bus to complete mutual communication. The bus can be an Industry Standard Architecture (ISA, Industry Standard Architecture) bus, a Peripheral Component Interconnect (PCI, Peripheral Component) bus, or an Extended Industry Standard Architecture (EISA, Extended Industry Standard Component) bus, etc. A computer program that can run on the processor is stored in the memory, and when the processor runs the computer program, the method for designing the parameters of the main circuit of the hybrid cascaded UHV DC system provided in Embodiment 1 is executed. Those skilled in the art can understand that the structure shown in FIG. 5 is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computing device to which the solution of the application is applied. The specific computing device can be More or fewer components than shown in the figures may be included, or some components may be combined, or have a different arrangement of components.

在一些实现中,上述的存储器中的逻辑指令可以通过软件功能单元的形式实现并作为独立的产品销售或使用时,可以存储在一个计算机可读取存储介质中。基于这样的理解,本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的部分可以以软件产品的形式体现出来,该计算机软件产品存储在一个存储介质中,包括若干指令用以使得一台计算机设备(可以是个人计算机,服务器,或者网络设备等)执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括:U盘、移动硬盘、只读存储器(ROM,Read-Only Memory)、随机存取存储器(RAM,Random Access Memory)、光盘等各种可以存储程序代码的介质。In some implementations, the above logic instructions in the memory may be implemented in the form of software functional units and may be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including Several instructions are used to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage media include: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), CD-ROM and other media that can store program codes.

在另一些实现中,处理器可以为中央处理器(CPU)、数字信号处理器(DSP)等各种类型通用处理器,在此不做限定。In other implementations, the processor may be various types of general-purpose processors such as a central processing unit (CPU) and a digital signal processor (DSP), which are not limited herein.

实施例四:本实施例一的混合级联特高压直流系统主回路参数设计方法可被具体实现为一种计算机程序产品,计算机程序产品可以包括计算机可读存储介质,其上载有用于执行本实施例一所述的混合级联特高压直流系统主回路参数设计方法的计算机可读程序指令。Embodiment 4: The method for designing the main circuit parameters of the hybrid cascaded UHV DC system in Embodiment 1 can be embodied as a computer program product, and the computer program product can include a computer-readable storage medium, which is loaded with a Computer-readable program instructions of the method for designing the parameters of the main circuit of the hybrid cascaded UHV DC system described in Example 1.

计算机可读存储介质可以是保持和存储由指令执行设备使用的指令的有形设备。计算机可读存储介质例如可以是但不限于电存储设备、磁存储设备、光存储设备、电磁存储设备、半导体存储设备或者上述的任意组合。A computer readable storage medium may be a tangible device that holds and stores instructions for use by an instruction execution device. A computer readable storage medium may be, for example, but is not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any combination of the above.

本说明书中的各个实施例均采用递进的方式描述,各个实施例之间相同相似的部分互相参见即可,每个实施例重点说明的都是与其他实施例的不同之处。尤其,对于系统实施例而言,由于其基本相似于方法实施例,所以描述的比较简单,相关之处参见方法实施例的部分说明即可。在本说明书的描述中,参考术语“一个实施例”、“一些实现”等的描述意指结合该实施例或示例描述的具体特征、结构、材料或者特点包含于本说明书实施例的至少一个实施例或示例中。在本说明书中,对上述术语的示意性表述不必须针对的是相同的实施例或示例。而且,描述的具体特征、结构、材料或者特点可以在任一个或多个实施例或示例中以合适的方式结合。此外,在不相互矛盾的情况下,本领域的技术人员可以将本说明书中描述的不同实施例或示例以及不同实施例或示例的特征进行结合和组合。Each embodiment in this specification is described in a progressive manner, the same and similar parts of each embodiment can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and for relevant parts, refer to part of the description of the method embodiment. In the description of this specification, descriptions with reference to the terms "one embodiment", "some implementations" and the like mean that specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one implementation of the embodiments of this specification. example or examples. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

本申请是参照根据本申请实施例的方法、设备(系统)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每一流程和/或方框、以及流程图和/或方框图中的流程和/或方框的结合。可提供这些计算机程序指令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器,使得通过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。The present application is described with reference to flowcharts and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and combinations of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a Means for realizing the functions specified in one or more steps of the flowchart and/or one or more blocks of the block diagram.

这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方式工作的计算机可读存储器中,使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品,该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上,使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理,从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart flow or flows and/or block diagram block or blocks.

最后应说明的是:以上实施例仅用以说明本发明的技术方案,而非对其限制;尽管参照前述实施例对本发明进行了详细的说明,本领域的普通技术人员应当理解:其依然可以对前述各实施例所记载的技术方案进行修改,或者对其中部分技术特征进行等同替换;而这些修改或者替换,并不使相应技术方案的本质脱离本发明各实施例技术方案的精神和范围。Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (9)

1.一种混合级联特高压直流系统主回路参数设计方法,其特征在于,包括:1. A method for designing the main circuit parameters of a hybrid cascaded UHV DC system, characterized in that it comprises: 确定混合级联特高压直流系统的运行方式;Determine the operation mode of the hybrid cascaded UHVDC system; 确定受端VSC和LCC的基本控制方式、VSC和LCC电压分配方式及各VSC之间的电流分配方式,在得出的约束方程下构建混合级联系统的稳态数学模型;Determine the basic control mode of VSC and LCC at the receiving end, the voltage distribution mode of VSC and LCC, and the current distribution mode between VSCs, and build a steady-state mathematical model of the hybrid cascaded system under the obtained constraint equations; 计算各运行方式下VSC的端口直流电压变化范围,并设计各运行方式下调制比范围,其中,设计各运行方式下调制比范围为:Calculate the variation range of the VSC port DC voltage in each operating mode, and design the modulation ratio range in each operating mode, where the modulation ratio range in each operating mode is: 计算各运行方式下的最大调制比M max=U dcfinal×M absmax/U dcinitU dcfinal为转带功率造成压降最大的工况下的故障后直流电压,U dcinit为转带功率造成压降最大的工况下的故障前直流电压,M absmax为保证柔性直流输出电压不过调制的最大调制比;按照能够满足系统谐波要求的电平数设计最小调制比M minCalculate the maximum modulation ratio M max = U dcfinal × M absmax / U dcinit in each operating mode, U dcfinal is the post-fault DC voltage under the condition where the transfer power causes the largest voltage drop, and U dcinit is the voltage drop caused by the transfer power The DC voltage before the fault under the maximum working condition, M absmax is the maximum modulation ratio to ensure that the flexible DC output voltage is not modulated; the minimum modulation ratio M min is designed according to the level number that can meet the harmonic requirements of the system; 基于VSC的PQ运行区间的约束条件,求解VSC的PQ运行区间,并确定柔直换流变需配置的档位范围;Based on the constraints of the PQ operating range of the VSC, the PQ operating range of the VSC is solved, and the gear range that needs to be configured for the soft direct commutation rheology is determined; 确定该运行方式下混合级联特高压直流系统的最大运行功率;Determine the maximum operating power of the hybrid cascaded UHVDC system under this operating mode; 基于系统的最大运行功率和VSC无功功率,求解混合级联系统的稳态数学模型,获得该系统的稳态运行参数。Based on the maximum operating power of the system and VSC reactive power, the steady-state mathematical model of the hybrid cascaded system is solved to obtain the steady-state operating parameters of the system. 2.根据权利要求1所述的混合级联特高压直流系统主回路参数设计方法,其特征在于,VSC和LCC的电压分配方式,包括:2. The method for designing the main circuit parameters of the hybrid cascaded UHVDC system according to claim 1, wherein the voltage distribution method of VSC and LCC includes: VSC和LCC按照等直流电压的方式分配,则对应约束方程为U dcvsc=U dclccU dcvscU dclcc分别为VSC和LCC的端口直流电压;VSC and LCC are distributed according to equal DC voltage, and the corresponding constraint equation is U dcvsc = U dclcc , U dcvsc and U dclcc are the port DC voltages of VSC and LCC respectively; VSC不考虑直流电压的波动,全部由LCC承担线路压降,则对应约束方程为U dcvsc=U setvscU dcvsc为VSC的端口直流电压,U setvsc为设定值。The VSC does not consider the fluctuation of the DC voltage, and the line voltage drop is all borne by the LCC. The corresponding constraint equation is U dcvsc = U setvsc , where U dcvsc is the DC voltage of the VSC port, and U setvsc is the set value. 3.根据权利要求2所述的混合级联特高压直流系统主回路参数设计方法,其特征在于,各VSC之间的电流分配方式,包括:3. The method for designing the main circuit parameters of the hybrid cascaded UHVDC system according to claim 2, wherein the current distribution mode between each VSC includes: 各VSC之间按照等电流的方式分配,则约束方程为:I vsc1=I vsc2=...I vscn=I dc/nI vsc1,...I vscn分别为第1到n个VSC的直流电流,I dc为流入VSC阀组的总电流;The VSCs are distributed according to the method of equal current, then the constraint equation is: I vsc1 = I vsc2 =... I vscn = I dc / n , I vsc1 , ... I vscn are the 1st to nth VSCs respectively DC current, I dc is the total current flowing into the VSC valve group; 各VSC之间独立指定运行功率,则约束方程为:I vsc1=P vsc1/U setvscI vsc2=P vsc2/U setvscI vscn=P vscn/U setvscI vscn=I dc-I vsc1-I vsc2I vsc(n-1)P vsc1P vsc2P vscn为VSC1、 VSC2…VSCn的有功功率。The operating power is independently specified between each VSC, and the constraint equation is: I vsc1 = P vsc1 / U setvsc , I vsc2 = P vsc2 / U setvscI vscn = P vscn / U setvsc and I vscn = I dc - I vsc1 - I vsc2 ... I vsc (n-1) , P vsc1 , P vsc2 ... P vscn are active powers of VSC1, VSC2 ... VSCn. 4.根据权利要求1所述的混合级联特高压直流系统主回路参数设计方法,其特征在于,求解VSC的PQ运行区间,包括:4. The method for designing the main circuit parameters of the hybrid cascaded UHV DC system according to claim 1, wherein solving the PQ operating interval of the VSC includes: a、确定VSC的PQ运行区间的限制条件,包括VSC的端口直流电压变化范围、调制比范围、交流电压变化范围、桥臂电流限制和变压器容量限制;a. Determine the limiting conditions of the PQ operating range of the VSC, including the DC voltage range of the VSC port, the modulation ratio range, the AC voltage range, the bridge arm current limit and the transformer capacity limit; b、基于约束条件,求解PQ运行区间,PQ运行区间取不同直流电压和交流电压组合下的交集;b. Based on the constraint conditions, solve the PQ operation interval, and the PQ operation interval takes the intersection of different DC voltage and AC voltage combinations; c、判断功率区间是否满足系统对功率交换的设定要求,如果为是,则确定PQ运行区间和VCS档位,如果为否,则进入d;c. Judging whether the power range meets the system’s setting requirements for power exchange, if yes, then determine the PQ operation range and VCS gear, if no, then enter d; d、若发出无功不足或桥臂电流导致功率限制,则增加负档位配置;若吸收无功不足,则增加正档位配置,进入步骤b。d. If the output reactive power is insufficient or the bridge arm current causes power limitation, then increase the negative gear configuration; if the absorbed reactive power is insufficient, increase the positive gear configuration and go to step b. 5.根据权利要求1所述的混合级联特高压直流系统主回路参数设计方法,其特征在于,PQ运行区间按照所有档位下的PQ运行区间的并集设计,当单一档位无法满足系统需求时,逐渐增大档位的配置范围以增大PQ运行区间,直到档位配置满足该运行方式下系统对VSC交换能力需求,或增加档位无法再增大VSC和系统的交换功率时为止,即得到该运行方式下的PQ运行区间,各运行方式下求得的档位的并集即为VSC设计的档位。5. The method for designing the main circuit parameters of the hybrid cascaded UHVDC system according to claim 1, wherein the PQ operating interval is designed according to the union of the PQ operating intervals under all gears, and when a single gear cannot meet the requirements of the system When required, gradually increase the configuration range of gears to increase the PQ operating range until the gear configuration meets the system's demand for VSC switching capacity in this operating mode, or until the switching power of the VSC and the system can no longer be increased by increasing the gear , that is, the PQ operating interval under this operating mode is obtained, and the union of the gears obtained under each operating mode is the gear designed by the VSC. 6.根据权利要求4或5所述的混合级联特高压直流系统主回路参数设计方法,其特征在于,增大档位的配置范围的方法,包括:当桥臂电流限制导致吸收或发出有功功率或无功功率不足时,增加负档位配置;当调制比限制导致吸收无功功率不足时,增加正档位配置;当调制比限制导致发出无功功率不足时,增加负档位配置。6. The method for designing the parameters of the main circuit of the hybrid cascaded UHVDC system according to claim 4 or 5, wherein the method for increasing the configuration range of gear positions includes: when the current limitation of the bridge arm causes the absorption or emission of active power When the power or reactive power is insufficient, increase the negative gear configuration; when the modulation ratio limit results in insufficient absorbed reactive power, increase the positive gear configuration; when the modulation ratio limit results in insufficient outgoing reactive power, increase the negative gear configuration. 7.一种混合级联特高压直流系统主回路参数设计系统,其特征在于,包括:7. A hybrid cascaded UHV DC system main circuit parameter design system, characterized in that it includes: 运行方式确定单元,被配置为确定混合级联特高压直流系统的运行方式;an operation mode determination unit configured to determine the operation mode of the hybrid cascaded UHVDC system; 模型构建单元,被配置为确定受端VSC和LCC的基本控制方式、VSC和LCC电压分配方式及各VSC之间的电流分配方式,在设定的约束方程下构建混合级联系统的稳态数学模型;The model construction unit is configured to determine the basic control mode of the VSC and LCC at the receiving end, the voltage distribution mode of the VSC and LCC, and the current distribution mode between each VSC, and construct the steady-state mathematics of the hybrid cascaded system under the set constraint equations Model; 参数确定单元,被配置为计算各运行方式下VSC的端口直流电压变化范围,并设计各运行方式下调制比范围;基于VSC的PQ运行区间的约束条件,求解VSC的PQ运行区间,并确定柔直换流变需配置的档位范围;确定该运行方式下混合级联特高压直流系统的最大运行功率;其中,设计各运行方式下调制比范围为:计算各运行方式下的最大调制比M max=U dcfinal×M absmax/U dcinitU dcfinal为转带功率造成压降最大的工况下的故障后直流电压,U dcinit为转带功率造成压降最大的工况下的故障前直流电压,M absmax为保证柔性直流输出电压不过调制的最大调制比;按照能够满足系统谐波要求的电平数设计最小调制比M minThe parameter determination unit is configured to calculate the variation range of the VSC port DC voltage in each operation mode, and design the modulation ratio range in each operation mode; based on the constraint conditions of the PQ operation interval of the VSC, solve the PQ operation interval of the VSC, and determine the flexible The range of gears that need to be configured for direct-conversion rheology; determine the maximum operating power of the hybrid cascaded UHV DC system in this operating mode; among them, the design range of modulation ratios in each operating mode is: Calculate the maximum modulation ratio M in each operating mode max = U dcfinal × M absmax / U dcinit , U dcfinal is the post-fault DC voltage under the condition of the largest voltage drop caused by the rotating power, U dcinit is the pre-fault DC voltage under the operating condition of the largest voltage drop caused by the rotating power , M absmax is the maximum modulation ratio to ensure that the flexible DC output voltage is not modulated; the minimum modulation ratio M min is designed according to the number of levels that can meet the harmonic requirements of the system; 模型计算单元,被配置为基于系统的最大运行功率和VSC无功功率,求解混合级联系统的稳态数学模型,获得该系统的稳态运行参数。The model calculation unit is configured to solve the steady-state mathematical model of the hybrid cascaded system based on the maximum operating power of the system and the VSC reactive power, and obtain the steady-state operating parameters of the system. 8.一种电子设备,其特征在于,包括计算机程序指令,其中,所述程序指令被处理器执行时用于实现权利要求1~6任一项所述的混合级联特高压直流系统主回路参数设计方法。8. An electronic device, characterized in that it includes computer program instructions, wherein the program instructions are used to implement the main circuit of the hybrid cascaded UHV DC system according to any one of claims 1 to 6 when executed by a processor Parametric Design Method. 9.一种计算机可读存储介质,其特征在于,所述计算机可读存储介质上存储有计算机程序指令,其中,所述程序指令被处理器执行时用于实现如权利要求1~6任一项所述的混合级联特高压直流系统主回路参数设计方法。9. A computer-readable storage medium, wherein computer program instructions are stored on the computer-readable storage medium, wherein the program instructions are used to implement any one of claims 1-6 when executed by a processor. The design method of the main circuit parameters of the hybrid cascaded UHV DC system described in the item.
CN202211307347.1A 2022-10-25 2022-10-25 Main loop parameter design method and system for hybrid cascade extra-high voltage direct current system Active CN115663876B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202211307347.1A CN115663876B (en) 2022-10-25 2022-10-25 Main loop parameter design method and system for hybrid cascade extra-high voltage direct current system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211307347.1A CN115663876B (en) 2022-10-25 2022-10-25 Main loop parameter design method and system for hybrid cascade extra-high voltage direct current system

Publications (2)

Publication Number Publication Date
CN115663876A CN115663876A (en) 2023-01-31
CN115663876B true CN115663876B (en) 2023-05-16

Family

ID=84990639

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202211307347.1A Active CN115663876B (en) 2022-10-25 2022-10-25 Main loop parameter design method and system for hybrid cascade extra-high voltage direct current system

Country Status (1)

Country Link
CN (1) CN115663876B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117239717B (en) * 2023-08-17 2024-04-05 国家电网有限公司华东分部 Determination method of hybrid cascade multi-terminal DC transient overvoltage risk suppression strategy

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103701145A (en) * 2014-01-02 2014-04-02 浙江大学 Mixed MMC-based mixed direct current power transmission system
CN106655235A (en) * 2016-10-18 2017-05-10 南方电网科学研究院有限责任公司 Energy balance regulation and control method and system of hybrid multi-terminal direct current system
CN107104455A (en) * 2017-05-15 2017-08-29 云南电网有限责任公司 The quick system recovery method for starting LCC HVDC
CN107968422A (en) * 2016-10-20 2018-04-27 中国电力科学研究院 Phase locking method for improving stability of exchange power of VSC and weak alternating current power grid
CN113452062A (en) * 2021-07-06 2021-09-28 国网江苏省电力有限公司经济技术研究院 MMC-HVDC transmission capacity determination method and system

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103094929B (en) * 2012-09-28 2015-04-15 华北电力大学 Method for fast building alternating current and direct current hybrid system small disturbance state-space model
CN107026465B (en) * 2017-05-17 2019-12-27 华北电力大学 Method for calculating flexible direct current steady state operation area in hybrid double-feed-in direct current system
CN107171352B (en) * 2017-05-17 2020-07-10 华北电力大学 Calculation method of flexible DC steady-state operation range in parallel hybrid DC system
CN109066756B (en) * 2018-08-01 2022-01-18 华南理工大学 VSC-HVDC linear active disturbance rejection control method for improving system transient stability
CN110138000B (en) * 2019-06-11 2022-08-16 河海大学 Hybrid direct-current power transmission system control parameter optimization method based on robust multi-objective optimization algorithm
CN112103998B (en) * 2020-09-09 2021-10-22 中国南方电网有限责任公司超高压输电公司检修试验中心 Method and device for calculation and analysis of steady-state operating characteristics of LCC-MMC hybrid DC transmission system
CN112332436B (en) * 2020-10-20 2022-09-02 天津大学 Coordination control method suitable for receiving-end series-parallel LCC-VSC direct current system
CN113162093A (en) * 2020-12-11 2021-07-23 华北电力大学 Active commutation type current source converter fundamental frequency control strategy applied to high-voltage direct-current power transmission
CN113452060B (en) * 2021-06-09 2022-08-02 华中科技大学 Analysis method and system for stable operation interval of VSC-LCC cascaded hybrid DC system
CN114139364A (en) * 2021-11-25 2022-03-04 广东电网有限责任公司 An electromechanical-electromagnetic hybrid simulation method and device based on a hybrid DC system
CN114583741A (en) * 2022-03-11 2022-06-03 国网经济技术研究院有限公司 Hybrid cascade direct-current transmission power band transfer capability optimization control method and system
CN114614487B (en) * 2022-03-31 2025-03-18 重庆大学 Voltage security region assessment method for HVDC transmission system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103701145A (en) * 2014-01-02 2014-04-02 浙江大学 Mixed MMC-based mixed direct current power transmission system
CN106655235A (en) * 2016-10-18 2017-05-10 南方电网科学研究院有限责任公司 Energy balance regulation and control method and system of hybrid multi-terminal direct current system
CN107968422A (en) * 2016-10-20 2018-04-27 中国电力科学研究院 Phase locking method for improving stability of exchange power of VSC and weak alternating current power grid
CN107104455A (en) * 2017-05-15 2017-08-29 云南电网有限责任公司 The quick system recovery method for starting LCC HVDC
CN113452062A (en) * 2021-07-06 2021-09-28 国网江苏省电力有限公司经济技术研究院 MMC-HVDC transmission capacity determination method and system

Also Published As

Publication number Publication date
CN115663876A (en) 2023-01-31

Similar Documents

Publication Publication Date Title
CN112510715B (en) Multi-port alternating current power grid flexible interconnection device and control method and system thereof
CN106026154B (en) The modeling method of extra-high voltage direct-current layer-specific access transmission system
CN111668846A (en) A photovoltaic dual-mode self-adaptive cross-platform absorption method and system
CN107359638B (en) A Multi-Port DC-DC Transformer System Topology with Stepless Regulation of DC Voltage
CN107086803A (en) A Capacitor-Voltage Balance Control Strategy for Modular Multilevel Converter
CN205595798U (en) Modified compounding in parallel type unified power flow controller
CN106936150B (en) A Parameter Optimal Configuration Method for Modular Multilevel DC Transmission System
CN115663876B (en) Main loop parameter design method and system for hybrid cascade extra-high voltage direct current system
CN108964120A (en) Low pressure distributed photovoltaic access capacity optimal control method
CN106356880A (en) MMC converting system and fault-tolerant control method thereof
CN115441750A (en) A hybrid AC exchanger
CN108599227B (en) MMC direct-current voltage balance control method for forming direct-current converter station based on MMC cascade connection
CN106529101A (en) Quick electromagnetic transient simulation method and device for modular multi-level converter
CN115241921A (en) Offshore wind power flexible directing system and method based on active power dynamic balance coordination
CN103904927B (en) Additional direct-current voltage control method for modular multi-level current converter
CN107769216A (en) A kind of voltage modulated method for the access of weak AC network
CN114553020A (en) A capacitor multiplexing type modular multilevel converter and its control method
CN107578118B (en) Optimization method and device for switching strategy of filter of direct-current power transmission system
CN105680453B (en) Improved parallel hybrid unified power flow controller
CN119275842A (en) A method for designing main circuit parameters of transformerless multi-terminal flexible interconnection device
CN209105050U (en) A cascaded 24-pulse converter topology
CN112436508A (en) Solid-state transformer capable of continuously running under fault working condition and regulation and control method thereof
CN111313424A (en) A three-phase four-wire general power quality controller and its control method
CN109149981B (en) A Multi-objective Optimization Method Based on Genetic Algorithm Applicable to MMC
CN117498460A (en) Offshore wind power direct current sending-out system and control method

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant