CN115102173A - A layered distributed control method for flexible diamond-type distribution flexible interconnected converters - Google Patents

A layered distributed control method for flexible diamond-type distribution flexible interconnected converters Download PDF

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CN115102173A
CN115102173A CN202111190569.5A CN202111190569A CN115102173A CN 115102173 A CN115102173 A CN 115102173A CN 202111190569 A CN202111190569 A CN 202111190569A CN 115102173 A CN115102173 A CN 115102173A
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power
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CN115102173B (en
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储琳琳
宗明
张宇俊
陈妍君
朱夏
周剑桥
施刚
张建文
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State Grid Shanghai Electric Power Co Ltd
Shanghai Jiao Tong University
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for AC mains or AC distribution networks
    • H02J3/04Circuit arrangements for AC mains or AC distribution networks for connecting networks of the same frequency but supplied from different sources
    • H02J3/06Controlling transfer of power between connected networks; Controlling sharing of load between connected networks
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for AC mains or AC distribution networks
    • H02J3/24Arrangements for preventing or reducing oscillations of power in networks
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for AC mains or AC distribution networks
    • H02J3/36Arrangements for transfer of electric power between AC networks via a high-tension DC link
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for AC mains or AC distribution networks
    • H02J3/38Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20The dispersed energy generation being of renewable origin

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Abstract

The invention discloses a layered distributed control method for a flexible diamond distribution flexible interconnection converter, which comprises the following steps: establishing a grid structure of a flexible interconnected power distribution network based on a power distribution interconnection converter; and constructing a layered distributed control strategy based on the grid structure and according to the structure and the principle of three-level control respectively, so as to realize the power flow control of the flexible interconnected power distribution network system. The invention realizes the multi-network coordination control and the optimized operation of the power distribution interconnection converter on the flexible interconnection power distribution network, can improve the voltage quality of a multi-region power distribution feeder line, reduce the line loss, optimize the operation level of the power distribution network, and can realize the seamless flexible switching between system-level control and local control.

Description

一种柔性钻石型配电柔性互联变换器分层分布式控制方法A layered distributed control method for flexible diamond-type distribution flexible interconnected converters

技术领域technical field

本发明涉及电力系统中电力电子技术、自动控制的技术领域,尤其涉及一种柔性钻石型配电柔性互联变换器分层分布式控制方法。The invention relates to the technical field of power electronic technology and automatic control in power systems, in particular to a layered distributed control method for flexible diamond-type distribution flexible interconnection converters.

背景技术Background technique

随着能源电力领域的革新和变化,传统配电网的局限性日益突出,所面临的挑战日益严峻。其中,主要问题包括:分布式可再生能源大规模并入电网,配电网功率双向流动,馈线间负载不平衡,节点电压越限;负荷种类多样化,传统配电网的结构和运行模式无法满足各种灵活负荷的需求;用户对于供电的可靠性和电能质量有着更高的要求。With the innovation and changes in the field of energy and power, the limitations of traditional distribution networks have become increasingly prominent, and the challenges they face are becoming increasingly severe. Among them, the main problems include: large-scale integration of distributed renewable energy into the power grid, bidirectional flow of power in the distribution network, unbalanced load between feeders, and node voltage exceeding the limit; diversified load types, the structure and operation mode of traditional distribution network cannot be Meet the needs of various flexible loads; users have higher requirements for the reliability of power supply and power quality.

在配电网中,线路电压低压越限经常存在和发生于城市配电网和其他地区配电网中,对电力系统的稳定运行和工业、商业、居民用电而言,都产生了严重影响。长久以来,学界及电力公司的关注点在于中高压系统的电能质量问题,而并未考虑配电网的电能质量问题。随着我国经济的发展,人民生活水平不断提高,对电能的需求越来越高。配电网的负荷越来越重、负荷类型越来越多、容量越来越大,因此,配电网的电压质量难以保证。In the distribution network, the line voltage low-voltage over-limit often exists and occurs in the urban distribution network and other regional distribution networks, which has a serious impact on the stable operation of the power system and the power consumption of industries, commerce, and residents. . For a long time, academic circles and power companies have focused on the power quality of medium and high voltage systems, but have not considered the power quality of distribution networks. With the development of my country's economy and the continuous improvement of people's living standards, the demand for electric energy is getting higher and higher. The load of the distribution network is getting heavier and heavier, the types of loads are increasing, and the capacity is increasing. Therefore, it is difficult to guarantee the voltage quality of the distribution network.

随着电力电子器件的发展,柔性直流配电技术不断完善。以电压源换流器为基础的柔性直流配电技术在中低压柔性互联配电技术中得到示范应用,形成了交直流混合的柔性互联化配电网,可以预见,未来的配电网中将会存在越来越多的分布式电源以及多种类型的负荷,对配电网的稳定运行来说,将会是一个挑战。With the development of power electronic devices, flexible DC power distribution technology has been continuously improved. The flexible DC power distribution technology based on voltage source converters has been demonstrated and applied in the medium and low voltage flexible interconnected power distribution technology, forming a flexible and interconnected power distribution network with a mix of AC and DC. There will be more and more distributed power sources and various types of loads, which will be a challenge to the stable operation of the distribution network.

发明内容SUMMARY OF THE INVENTION

本发明解决的技术问题是:配电网的负荷越来越重、负荷类型越来越多、容量越来越大,因此,配电网的电压质量难以保证,未来的配电网中将会存在越来越多的分布式电源以及多种类型的负荷,对配电网的稳定运行来说,将会是一个挑战。The technical problem solved by the invention is that the load of the distribution network is getting heavier, the types of loads are more and more, and the capacity is larger and larger. Therefore, the voltage quality of the distribution network is difficult to guarantee, and the future distribution network will There are more and more distributed power sources and various types of loads, which will be a challenge to the stable operation of the distribution network.

为解决上述技术问题,本发明提供如下技术方案:建立基于配电互联变换器的柔性互联化配电网的网架结构;基于所述网架结构并分别根据三个层级控制的结构及原理构建分层分布式控制策略,实现对柔性互联配电系统的潮流控制。In order to solve the above technical problems, the present invention provides the following technical solutions: establish a grid structure of a flexible interconnected distribution network based on distribution interconnection converters; The layered distributed control strategy realizes the power flow control of the flexible interconnected power distribution system.

作为优选,所述网架结构包括将各个多互联变换器配置在配电馈线末端,通过所述多互联变换器间的直流母线进行互联。Preferably, the grid structure includes arranging each multi-interconnected converter at the end of the power distribution feeder, and interconnecting the multi-interconnected converters through the DC bus.

作为优选,所述三个层级包括换流器、本地、系统级三个层面。Preferably, the three levels include converter level, local level, and system level.

作为优选,所述换流器层面的控制原理包括,定义三相电压型PWM整流器作为交直流换流器,其经过坐标变换的数学模型为:Preferably, the control principle at the converter level includes defining a three-phase voltage-type PWM rectifier as an AC-DC converter, and its mathematical model after coordinate transformation is:

Figure RE-GDA0003490859290000021
Figure RE-GDA0003490859290000021

其中,ed,eq为交流电压源电压dq轴分量,id,iq为三相交流电流dq轴分量,电阻R与电感L是交流侧主电路中的电感与电阻,vdc为直流侧电压, sd,sq为开关函数的dq轴分量,C为直流电容,RL负载电阻;Among them, ed , e q are the dq -axis components of the AC voltage source voltage, id , i q are the dq -axis components of the three-phase AC current, the resistance R and the inductance L are the inductance and resistance in the main circuit of the AC side, and v dc is the direct current side voltage, s d , s q are the dq-axis components of the switching function, C is the DC capacitance, and R L is the load resistance;

定义所述交流侧电感L与直流侧电容C为:The AC side inductance L and the DC side capacitance C are defined as:

Figure RE-GDA0003490859290000022
Figure RE-GDA0003490859290000022

Figure RE-GDA0003490859290000023
Figure RE-GDA0003490859290000023

式中,Em为电网相电动势,Ts为开关周期,vdc为直流电压,Im为交流基波相电流,Δimax为电流最大允许脉动量,取20%Im,Timax为最大惯性时间常数,ΔPL,max为负载功率最大变化量,Δvdc,max为直流电压最大变化量,

Figure RE-GDA0003490859290000024
为限定直流电压上升时间,RLe为额定直流负载电阻,Idm为额定直流电流,vd0为直流电压稳态最低值,vde为直流电压额定值;In the formula, Em is the grid phase electromotive force, T s is the switching period, v dc is the DC voltage, Im is the AC fundamental phase current, Δi max is the maximum allowable current ripple, take 20% of I m , and T imax is the maximum Inertia time constant, ΔP L,max is the maximum variation of load power, Δv dc,max is the maximum variation of DC voltage,
Figure RE-GDA0003490859290000024
In order to limit the DC voltage rise time, R Le is the rated DC load resistance, I dm is the rated DC current, v d0 is the minimum steady-state value of the DC voltage, and v de is the rated value of the DC voltage;

在控制中引入PI控制器,将所述PI控制器的增益参数定义为:A PI controller is introduced into the control, and the gain parameter of the PI controller is defined as:

Figure RE-GDA0003490859290000031
Figure RE-GDA0003490859290000031

其中,Ts为PWM开关周期,KPWM为整流桥等效增益,与调制方式有关, KP、KI分别是PI调节器的比例环节和积分环节的增益系数;Among them, T s is the PWM switching period, K PWM is the equivalent gain of the rectifier bridge, which is related to the modulation method, and K P and K I are the gain coefficients of the proportional link and the integral link of the PI regulator, respectively;

将控制环的闭环传递函数简化为一个惯性环节:Simplify the closed-loop transfer function of the control loop to an inertial link:

Figure RE-GDA0003490859290000032
Figure RE-GDA0003490859290000032

作为优选,所述本地层面的控制原理包括一次调压控制和二次调压控制。Preferably, the control principles at the local level include primary voltage regulation control and secondary voltage regulation control.

作为优选,所述一次调压控制包括,Preferably, the primary voltage regulation control includes,

建立下垂方程,归一化方程及经过归一化后的下垂方程为:The sag equation is established, the normalized equation and the normalized sag equation are:

Figure RE-GDA0003490859290000033
Figure RE-GDA0003490859290000033

Figure RE-GDA0003490859290000034
Figure RE-GDA0003490859290000034

Pac1=P1+Pdc1 P ac1 =P 1 +P dc1

控制交流侧归一化电压与直流侧归一化电压相等,即:The normalized voltage of the control AC side is equal to the normalized voltage of the DC side, namely:

Figure RE-GDA0003490859290000035
Figure RE-GDA0003490859290000035

Figure RE-GDA0003490859290000036
Figure RE-GDA0003490859290000036

............

Figure RE-GDA0003490859290000037
Figure RE-GDA0003490859290000037

定义各条线路的直流归一化电压相等,为:It is defined that the DC normalized voltage of each line is equal, as:

Figure RE-GDA0003490859290000038
Figure RE-GDA0003490859290000038

联立以上式子,经过本地层面控制的一次调压后,可以得到:Combining the above formulas, after a voltage regulation controlled by the local level, we can get:

Figure RE-GDA0003490859290000041
Figure RE-GDA0003490859290000041

Figure RE-GDA0003490859290000042
Figure RE-GDA0003490859290000042

其中,N表示有N个配网柔性互联,Z1,…,Zn分别为第1,…,n个配网的线路阻抗,P1,…,Pn分别为第1,…,n个配网的负载功率,Vac1,…,Vacn分别为第1,…,n个配网的线路末端电压,Pc1,…,Pcn分别为第1,…,n个配网的交直流变换器传递的有功功率,Qc1,…,Qcn分别为第1,…,n个配网的交直流变换器传递的无功功率,Pdc为直流源或荷的功率。Among them, N represents that there are N flexible interconnections of distribution networks, Z 1 ,…,Z n are the line impedances of the first,…,n distribution networks, respectively, P 1 ,…,P n are the first,…,n respectively. The load power of the distribution network, V ac1 ,…,V acn are the line end voltages of the 1st,…,n distribution networks, respectively, P c1 ,…,P cn are the AC and DC voltages of the 1st,…,n distribution networks, respectively The active power delivered by the converter, Q c1 ,…,Q cn are the reactive power delivered by the AC/DC converters of the 1st,…,n distribution network respectively, and P dc is the power of the DC source or load.

作为优选,所述二次调压包括,在所述一次调压的基础上,定义有功功率与无功功率传输为给定值,即控制各馈线的功率传递为给定值

Figure RE-GDA0003490859290000043
则各线路的下垂方程变为:Preferably, the secondary voltage regulation includes, on the basis of the primary voltage regulation, defining the transmission of active power and reactive power as a given value, that is, controlling the power transmission of each feeder to a given value
Figure RE-GDA0003490859290000043
Then the droop equation of each line becomes:

Figure RE-GDA0003490859290000044
Figure RE-GDA0003490859290000044

Figure RE-GDA0003490859290000045
Figure RE-GDA0003490859290000045

............

Figure RE-GDA0003490859290000046
Figure RE-GDA0003490859290000046

稳态时,功率与电压方程满足:At steady state, the power and voltage equations satisfy:

Figure RE-GDA0003490859290000047
Figure RE-GDA0003490859290000047

系统满足:The system satisfies:

Figure RE-GDA0003490859290000048
Figure RE-GDA0003490859290000048

各线路经柔性互联后,定义各条线路的直流归一化电压相等,为:After each line is flexibly interconnected, the DC normalized voltage of each line is defined to be equal, which is:

Figure RE-GDA0003490859290000049
Figure RE-GDA0003490859290000049

联立以上式子,可以得到:Combining the above equations, we can get:

Figure RE-GDA00034908592900000410
Figure RE-GDA00034908592900000410

Figure RE-GDA00034908592900000411
Figure RE-GDA00034908592900000411

作为优选,所述系统层面的控制原理包括,根据系统采集的各节点的电压信息及功率信息,通过智能算法的检索,计算得到系统的最优运行状态。Preferably, the control principle at the system level includes, according to the voltage information and power information of each node collected by the system, through intelligent algorithm retrieval, calculating and obtaining the optimal operating state of the system.

作为优选,还包括,根据一般数学模型建立实际问题的数学模型,所述一般数学模型为:Preferably, it also includes establishing a mathematical model of the actual problem according to a general mathematical model, where the general mathematical model is:

minf=f(x,u)minf=f(x,u)

{s.t.g(x,u)=0{s.t.g(x,u)=0

h(x,u)≤0h(x,u)≤0

其中,f(x,u)是目标函数,g(x,u)和h(x,u)分别为等式约束和不等式约束,x、u分别为控制变量和状态变量。Among them, f(x, u) is the objective function, g(x, u) and h(x, u) are equality constraints and inequality constraints, respectively, and x and u are control variables and state variables, respectively.

本发明的有益效果:本发明实现了配电互联变换器对于柔性互联化配电网的多网协调控制与优化运行,能够提高多区域配电馈线电压质量,减小线路损耗,优化配电网运行水平,并可实现系统级控制和本地控制的无缝灵活切换。Beneficial effects of the invention: the invention realizes the coordinated control and optimal operation of the distribution interconnection converter for the flexible interconnected distribution network, and can improve the voltage quality of the multi-region distribution feeder, reduce the line loss, and optimize the distribution network. Operation level, and can achieve seamless and flexible switching between system-level control and local control.

附图说明Description of drawings

图1为本发明一个实施例提供的一种柔性钻石型配电柔性互联变换器分层分布式控制方法的整体流程结构示意图;1 is a schematic diagram of the overall flow structure of a layered distributed control method for a flexible diamond-type power distribution flexible interconnection converter provided by an embodiment of the present invention;

图2为本发明一个实施例提供的一种柔性钻石型配电柔性互联变换器分层分布式控制方法的系统结构示意图;2 is a schematic diagram of the system structure of a layered distributed control method for a flexible diamond-type distribution flexible interconnection converter provided by an embodiment of the present invention;

图3为本发明一个实施例提供的一种柔性钻石型配电柔性互联变换器分层分布式控制方法的基于前馈解耦合的电流内环控制框图;3 is a block diagram of a current inner loop control based on feedforward decoupling of a layered distributed control method for a flexible diamond-type distribution flexible interconnection converter provided by an embodiment of the present invention;

图4为本发明一个实施例提供的一种柔性钻石型配电柔性互联变换器分层分布式控制方法的单个配网线路等效电路图;4 is an equivalent circuit diagram of a single distribution network line of a layered distributed control method for a flexible diamond-type distribution flexible interconnection converter provided by an embodiment of the present invention;

图5为本发明一个实施例提供的一种柔性钻石型配电柔性互联变换器分层分布式控制方法的本地层面控制的无通讯的一次调压控制框图;5 is a block diagram of a primary voltage regulation control without communication controlled by a local level of a layered distributed control method for a flexible diamond-type power distribution flexible interconnection converter provided by an embodiment of the present invention;

图6为本发明一个实施例提供的一种柔性钻石型配电柔性互联变换器分层分布式控制方法的柔性互联化配电网等效电路图;6 is an equivalent circuit diagram of a flexible interconnected distribution network of a layered distributed control method for a flexible diamond-type distribution flexible interconnected converter provided by an embodiment of the present invention;

图7为本发明一个实施例提供的一种柔性钻石型配电柔性互联变换器分层分布式控制方法的本地层面控制的无通讯的一次调压原理示意图;7 is a schematic diagram of the principle of primary voltage regulation without communication controlled at the local level of a layered distributed control method for a flexible diamond-type power distribution flexible interconnection converter provided by an embodiment of the present invention;

图8为本发明一个实施例提供的一种柔性钻石型配电柔性互联变换器分层分布式控制方法的本地层面控制的有通讯的二次调压控制框图;8 is a block diagram of a secondary voltage regulation control with communication controlled at a local level of a layered distributed control method for a flexible diamond-type distribution flexible interconnection converter provided by an embodiment of the present invention;

图9为本发明一个实施例提供的一种柔性钻石型配电柔性互联变换器分层分布式控制方法的本地层面控制的有通讯的二次调压原理示意图;9 is a schematic diagram of the principle of secondary voltage regulation with communication controlled at the local level of a layered distributed control method for a flexible diamond-type power distribution flexible interconnection converter provided by an embodiment of the present invention;

图10为本发明一个实施例提供的一种柔性钻石型配电柔性互联变换器分层分布式控制方法的系统层面控制的算法框图;10 is an algorithm block diagram of a system-level control of a layered distributed control method for a flexible diamond-type distribution flexible interconnection converter provided by an embodiment of the present invention;

图11为本发明一个实施例提供的一种柔性钻石型配电柔性互联变换器分层分布式控制方法的仿真算例电路图;11 is a circuit diagram of a simulation example of a layered distributed control method for a flexible diamond-type distribution flexible interconnection converter provided by an embodiment of the present invention;

图12为本发明一个实施例提供的一种柔性钻石型配电柔性互联变换器分层分布式控制方法的线路1、线路2的有功功率传递的仿真结果示意图;12 is a schematic diagram of a simulation result of the active power transfer of line 1 and line 2 of a layered distributed control method for a flexible diamond-type distribution flexible interconnection converter provided by an embodiment of the present invention;

图13为本发明一个实施例提供的一种柔性钻石型配电柔性互联变换器分层分布式控制方法的线路1、线路2的无功功率传递的仿真结果示意图;13 is a schematic diagram of a simulation result of the reactive power transfer of line 1 and line 2 of a layered distributed control method for a flexible diamond-type distribution flexible interconnection converter provided by an embodiment of the present invention;

图14为本发明一个实施例提供的一种柔性钻石型配电柔性互联变换器分层分布式控制方法的线路1各节点电压的仿真结果示意图。FIG. 14 is a schematic diagram of a simulation result of the voltage of each node of line 1 in a layered distributed control method for a flexible diamond-type distribution flexible interconnection converter provided by an embodiment of the present invention.

具体实施方式Detailed ways

为使本发明的上述目的、特征和优点能够更加明显易懂,下面结合说明书附图对本发明的具体实施方式做详细的说明,显然所描述的实施例是本发明的一部分实施例,而不是全部实施例。基于本发明中的实施例,本领域普通人员在没有做出创造性劳动前提下所获得的所有其他实施例,都应当属于本发明的保护的范围。In order to make the above objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Example. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

在下面的描述中阐述了很多具体细节以便于充分理解本发明,但是本发明还可以采用其他不同于在此描述的其它方式来实施,本领域技术人员可以在不违背本发明内涵的情况下做类似推广,因此本发明不受下面公开的具体实施例的限制。Many specific details are set forth in the following description to facilitate a full understanding of the present invention, but the present invention can also be implemented in other ways different from those described herein, and those skilled in the art can do so without departing from the connotation of the present invention. Similar promotion, therefore, the present invention is not limited by the specific embodiments disclosed below.

其次,此处所称的“一个实施例”或“实施例”是指可包含于本发明至少一个实现方式中的特定特征、结构或特性。在本说明书中不同地方出现的“在一个实施例中”并非均指同一个实施例,也不是单独的或选择性的与其他实施例互相排斥的实施例。Second, reference herein to "one embodiment" or "an embodiment" refers to a particular feature, structure, or characteristic that may be included in at least one implementation of the present invention. The appearances of "in one embodiment" in various places in this specification are not all referring to the same embodiment, nor are they separate or selectively mutually exclusive from other embodiments.

实施例1Example 1

参照图1-图10,为本发明的一个实施例,提供了一种柔性钻石型配电柔性互联变换器分层分布式控制方法,包括:1-10, which is an embodiment of the present invention, provides a layered distributed control method for a flexible diamond-type power distribution flexible interconnection converter, including:

S1:建立基于配电互联变换器的柔性互联化配电网的网架结构;需要说明的是:S1: Establish a grid structure of a flexible interconnected distribution network based on distribution interconnection converters; it should be noted that:

网架结构包括将各个多互联变换器配置在配电馈线末端,通过多互联变换器间的直流母线进行互联。The grid structure includes arranging each multi-interconnected converter at the end of the distribution feeder, and interconnected by the DC bus between the multi-interconnected converters.

三个层级包括换流器、本地、系统级三个层面。The three levels include converter, local and system level.

具体的,基于多互联变换器(VSC)的柔性互联化配电网的网架结构中,各个VSC将配置在配电馈线末端,通过VSC间的直流母线互联,可实现相邻馈线间柔性互联,该网架结构为多区域网间及馈线间提供了新的功率流通路径,可以实现配电网网间功率的灵活调节与互济互供。Specifically, in the grid structure of the flexible interconnected distribution network based on multiple interconnection converters (VSCs), each VSC will be configured at the end of the distribution feeder, and the DC bus interconnection between the VSCs can realize flexible interconnection between adjacent feeders , the grid structure provides a new power flow path between multi-area networks and feeders, and can realize flexible adjustment and mutual supply of power between distribution networks.

在柔性互联化配电网的网架结构下,各VSC需根据馈线节点电压、负荷信息进行协调控制,从而实现配电网网间潮流互动与灵活调节,为此,本发明提出一种多互联变换器的分层分布式控制策略,该分层分布式控制的核心在于控制各条馈线及各个配电子网所交互的功率,从而解决交流侧线路中存在的电压越限、线路损耗大、可再生能源消纳能力不足等诸多问题,分层分布式控制通过换流器、本地、系统级三个层面的控制,实现对柔性互联配电系统的潮流控制,优化配电网的运行水平。Under the grid structure of the flexible interconnected distribution network, each VSC needs to coordinate and control according to the voltage and load information of the feeder node, so as to realize the interaction and flexible adjustment of the power flow between the distribution networks. Therefore, the present invention proposes a multi-interconnection The layered distributed control strategy of the converter, the core of the layered distributed control is to control the power interacted by each feeder and each distribution network, so as to solve the problem of voltage over-limit, large line loss, and possible problems in the AC side line. Due to the lack of renewable energy absorbing capacity and many other problems, hierarchical distributed control realizes the power flow control of the flexible interconnected power distribution system and optimizes the operation level of the power distribution network through three levels of control: inverter, local, and system level.

S2:基于网架结构并分别根据三个层级控制的结构及原理构建分层分布式控制策略,实现对柔性互联配电系统的潮流控制;需要说明的是:S2: Based on the grid structure and according to the structure and principle of the three-level control, a layered distributed control strategy is constructed to realize the power flow control of the flexible interconnected power distribution system; it should be noted that:

首先,换流器层面的控制目的是将输入的电流信号处理变换输出 AC/DC变换器开关PWM调制波形,控制交流测电流、直流侧电压稳定,实现功率双向流动,控制交直流侧功率交换。换流器层面的控制的原理如下:First of all, the control purpose at the converter level is to process and transform the input current signal to output the AC/DC converter switch PWM modulation waveform, control the AC current measurement, the DC side voltage stability, realize the bidirectional power flow, and control the AC/DC side power exchange. The control principle at the converter level is as follows:

三相电压型PWM整流器因其谐波含量少、功率因数高、动态响应快等特点,而在配网中得到广泛应用,因此,选择三相电压型PWM整流器作为交直流换流器。其经过坐标变换的数学模型为:Three-phase voltage-type PWM rectifiers are widely used in distribution networks because of their low harmonic content, high power factor, and fast dynamic response. Therefore, three-phase voltage-type PWM rectifiers are selected as AC-DC converters. The mathematical model of its coordinate transformation is:

Figure RE-GDA0003490859290000081
Figure RE-GDA0003490859290000081

其中,ed,eq为交流电压源电压dq轴分量,id,iq为三相交流电流dq轴分量,电阻R与电感L是交流侧主电路中的电感与电阻,vdc为直流侧电压, sd,sq为开关函数的dq轴分量,C为直流电容,RL负载电阻;Among them, ed , e q are the dq -axis components of the AC voltage source voltage, id , i q are the dq -axis components of the three-phase AC current, the resistance R and the inductance L are the inductance and resistance in the main circuit of the AC side, and v dc is the direct current side voltage, s d , s q are the dq-axis components of the switching function, C is the DC capacitance, and R L is the load resistance;

为改善系统的运行性能,需要选择适当的交流侧电感与直流侧电容,定义交流侧电感L与直流侧电容C为:In order to improve the operating performance of the system, it is necessary to select the appropriate AC side inductance and DC side capacitance. The AC side inductance L and the DC side capacitance C are defined as:

Figure RE-GDA0003490859290000082
Figure RE-GDA0003490859290000082

Figure RE-GDA0003490859290000083
Figure RE-GDA0003490859290000083

式中,Em为电网相电动势,Ts为开关周期,vdc为直流电压,Im为交流基波相电流,Δimax为电流最大允许脉动量,取20%Im,Timax为最大惯性时间常数,ΔPL,max为负载功率最大变化量,Δvdc,max为直流电压最大变化量,

Figure RE-GDA0003490859290000086
为限定直流电压上升时间,RLe为额定直流负载电阻,Idm额定直流电流,vd0为直流电压稳态最低值,vde为直流电压额定值;In the formula, Em is the grid phase electromotive force, T s is the switching period, v dc is the DC voltage, Im is the AC fundamental phase current, Δi max is the maximum allowable current ripple, take 20% of I m , and T imax is the maximum Inertia time constant, ΔP L,max is the maximum variation of load power, Δv dc,max is the maximum variation of DC voltage,
Figure RE-GDA0003490859290000086
In order to limit the DC voltage rise time, R Le is the rated DC load resistance, I dm is the rated DC current, v d0 is the minimum steady-state value of the DC voltage, and v de is the rated value of the DC voltage;

可根据该数学模型建立基于前馈解耦合的电流内环控制,控制框图如图3所示;在控制中引入PI控制器,其参数设计将对系统的动态性能产生影响,将PI控制器的增益参数定义为:According to this mathematical model, the current inner loop control based on feedforward decoupling can be established, and the control block diagram is shown in Figure 3; the PI controller is introduced into the control, and its parameter design will have an impact on the dynamic performance of the system. The gain parameter is defined as:

Figure RE-GDA0003490859290000084
Figure RE-GDA0003490859290000084

其中,Ts为PWM开关周期,KPWM为整流桥等效增益,与调制方式有关, KP、KI分别是PI调节器的比例环节和积分环节的增益系数;Among them, T s is the PWM switching period, K PWM is the equivalent gain of the rectifier bridge, which is related to the modulation method, and K P and K I are the gain coefficients of the proportional link and the integral link of the PI regulator, respectively;

最终可将控制环的闭环传递函数简化为一个惯性环节:Finally, the closed-loop transfer function of the control loop can be simplified to an inertial link:

Figure RE-GDA0003490859290000085
Figure RE-GDA0003490859290000085

进一步的,本地层面的控制目的是在无通讯线路时仅根据本地电压信息控制馈线间的功率交互,改善线路末端电压质量问题,称为一次调压;以及在有通讯线路时,根据配电网各个节点的电压及功率信息,分析计算最优运行状态,并通过控制功率交互,使系统运行于该最优状态,称为二次调压。Further, the control purpose at the local level is to control the power interaction between feeders only according to the local voltage information when there is no communication line, so as to improve the voltage quality problem at the end of the line, which is called primary voltage regulation; and when there is a communication line, according to the distribution network. The voltage and power information of each node is used to analyze and calculate the optimal operating state, and by controlling the power interaction, the system can operate in the optimal state, which is called secondary voltage regulation.

具体的,本地层面的控制的原理如下:Specifically, the principle of control at the local level is as follows:

假设有N个配网柔性互联,Z1,…,Zn分别为第1,…,n个配网的线路阻抗, P1,…,Pn分别为第1,…,n个配网的负载功率,Vac1,…,Vacn分别为第1,…,n个配网的线路末端电压,Pc1,…,Pcn分别为第1,…,n个配网的交直流变换器传递的有功功率,Qc1,…,Qcn分别为第1,…,n个配网的交直流变换器传递的无功功率,Pdc为直流源/荷的功率,单个配电网的等效电路图如图4所示。Assuming that there are N flexible interconnection of distribution networks, Z 1 ,…,Z n are the line impedances of the 1st,…,n distribution networks, respectively, P 1 ,…,P n are the 1st,…,n distribution networks, respectively. Load power, V ac1 ,…,V acn are the line end voltages of the 1st,…,n distribution networks, respectively, P c1 ,…,P cn are the AC/DC converter transmissions of the 1st,…,n distribution networks, respectively The active power of , Q c1 ,…,Q cn are the reactive power transmitted by the AC-DC converters of the 1st,…,nth distribution network respectively, P dc is the power of the DC source/load, the equivalent of a single distribution network The circuit diagram is shown in Figure 4.

考虑系统在无通讯线路的状态,应用一次调压,经过分析,各配网传递的有功功率与线路末端电压满足自然下垂特性,因此可以建立下垂方程,归一化方程及经过归一化后的下垂方程为:Considering that the system is in the state of no communication line, a voltage regulation is applied. After analysis, the active power transmitted by each distribution network and the voltage at the end of the line meet the natural droop characteristics. Therefore, the droop equation, the normalized equation and the normalized droop equation can be established. The sag equation is:

Figure RE-GDA0003490859290000091
Figure RE-GDA0003490859290000091

Figure RE-GDA0003490859290000092
Figure RE-GDA0003490859290000092

Pac1=P1+Pdc1 P ac1 =P 1 +P dc1

本地层面控制无通讯的一次调压控制框图如图5所示,控制交流侧归一化电压与直流侧归一化电压相等,即:The block diagram of the primary voltage regulation control without communication at the local level is shown in Figure 5. The normalized voltage of the control AC side is equal to the normalized voltage of the DC side, namely:

Figure RE-GDA0003490859290000093
Figure RE-GDA0003490859290000093

Figure RE-GDA0003490859290000094
Figure RE-GDA0003490859290000094

............

Figure RE-GDA0003490859290000095
Figure RE-GDA0003490859290000095

各线路经柔性互联后,等效电路图如图6所示,定义各条线路的直流归一化电压相等,为:After each line is flexibly interconnected, the equivalent circuit diagram is shown in Figure 6. It is defined that the DC normalized voltage of each line is equal, which is:

Figure RE-GDA0003490859290000096
Figure RE-GDA0003490859290000096

联立以上式子,经过本地层面控制的一次调压后,可以得到:Combining the above formulas, after a voltage regulation controlled by the local level, we can get:

Figure RE-GDA0003490859290000097
Figure RE-GDA0003490859290000097

Figure RE-GDA0003490859290000098
Figure RE-GDA0003490859290000098

其中,控制原理如图7所示。Among them, the control principle is shown in Figure 7.

在系统无通讯线路时,采用本地层面控制一次调压;在配电网实际运行中,当线路阻抗一定时,线路的末端电压由线路的负载功率决定,负载功率较高,则线路末端电压降低较多;负载功率较低,线路末端电压降低较少;一次调压后的结果式表明,多条馈线柔性互联后,各条线路的交流侧归一化电压位于同一电压水平,各条线路的功率实现了互补互济。When there is no communication line in the system, the local level is used to control the primary voltage regulation; in the actual operation of the distribution network, when the line impedance is constant, the terminal voltage of the line is determined by the load power of the line. If the load power is higher, the voltage at the end of the line decreases. The load power is low, and the voltage at the end of the line decreases less; the result formula after one-time voltage regulation shows that after multiple feeders are flexibly interconnected, the AC side normalized voltage of each line is at the same voltage level, and the voltage of each line is at the same voltage level. The power is complementary to each other.

考虑系统在有通讯线路的状态,应用二次调压,在一次调压的基础上,定义有功功率与无功功率传输为给定值,即控制各馈线的功率传递为给定值

Figure RE-GDA0003490859290000101
则各线路的下垂方程变为:Considering the state of the system with communication lines, the secondary voltage regulation is applied. On the basis of the primary voltage regulation, the transmission of active power and reactive power is defined as a given value, that is, the power transmission of each feeder is controlled to a given value.
Figure RE-GDA0003490859290000101
Then the droop equation of each line becomes:

Figure RE-GDA0003490859290000102
Figure RE-GDA0003490859290000102

Figure RE-GDA0003490859290000103
Figure RE-GDA0003490859290000103

............

Figure RE-GDA0003490859290000104
Figure RE-GDA0003490859290000104

本地层面控制的有通讯的二次调压控制框图如图8所示,稳态时,功率与电压方程满足:The block diagram of the secondary voltage regulation control with communication controlled at the local level is shown in Figure 8. At steady state, the power and voltage equations satisfy:

Figure RE-GDA0003490859290000105
Figure RE-GDA0003490859290000105

系统满足:The system satisfies:

Figure RE-GDA0003490859290000106
Figure RE-GDA0003490859290000106

各线路经柔性互联后,等效电路图如图5所示,定义各条线路的直流归一化电压相等,为:After each line is flexibly interconnected, the equivalent circuit diagram is shown in Figure 5. It is defined that the DC normalized voltage of each line is equal, which is:

Figure RE-GDA0003490859290000107
Figure RE-GDA0003490859290000107

联立以上式子,可以得到:Combining the above equations, we can get:

Figure RE-GDA0003490859290000108
Figure RE-GDA0003490859290000108

Figure RE-GDA0003490859290000109
Figure RE-GDA0003490859290000109

其中,控制原理如图9所示。Among them, the control principle is shown in Figure 9.

在系统有通讯线路时,采用本地层面控制的二次调压,控制有功功率与无功功率交互为给定值,精确控制各馈线的功率传递,根据需求调整各条线路运行的状态,为分层分布式控制系统层面与本地层面的控制提供了接口。When there is a communication line in the system, the secondary voltage regulation controlled at the local level is used to control the interaction between active power and reactive power as a given value, accurately control the power transfer of each feeder, and adjust the operation status of each line according to the demand. Layer Distributed control system layer provides interface with local layer control.

最后,系统层面的控制目的是根据系统采集的各节点的电压信息及功率信息,通过智能算法的检索,计算得到系统的最优运行状态,从而统筹各区域的功率调度,需要考虑各个节点处的电压水平不越限,同时满足系统整体的功率损耗最小这两个问题,优化系统整体运行情况,提高系统整体运行的经济性。系统层面的控制的原理如下:Finally, the purpose of control at the system level is to obtain the optimal operating state of the system through intelligent algorithm retrieval based on the voltage information and power information of each node collected by the system, so as to coordinate the power scheduling of each area. The voltage level does not exceed the limit, and at the same time, it meets the two problems of the minimum power loss of the overall system, optimizes the overall operation of the system, and improves the economy of the overall operation of the system. The principle of system-level control is as follows:

本质上来说,系统层面的控制所解决的是一个最优潮流问题;电力系统的最优潮流问题是一个复杂的带约束的非线性规划问题,在特定的安全约束条件下,通过调节系统中可利用的控制手段,实现预定目标最优的系统稳定运行状态;它兼顾了安全性、经济型、可靠性等多个方面;其中,一般的数学模型可表示为:Essentially, the control at the system level solves an optimal power flow problem; the optimal power flow problem of a power system is a complex nonlinear programming problem with constraints. The control method used is used to achieve the optimal system stable operation state of the predetermined target; it takes into account many aspects such as safety, economy, reliability, etc. Among them, the general mathematical model can be expressed as:

minf=f(x,u)minf=f(x,u)

{s.t.g(x,u)=0{s.t.g(x,u)=0

h(x,u)≤0h(x,u)≤0

其中,f(x,u)是目标函数,g(x,u)和h(x,u)分别为等式约束和不等式约束,x、u分别为控制变量和状态变量。:Among them, f(x, u) is the objective function, g(x, u) and h(x, u) are equality constraints and inequality constraints, respectively, and x and u are control variables and state variables, respectively. :

从该数学模型来看,一般可以根据实际需求设置希望达到的目标函数,根据目标函数中的变量,考虑各方面的局限性,设计与之相适应的约束条件,从而建立起实际问题的数学模型。From the mathematical model, the desired objective function can generally be set according to the actual needs, and the constraints of various aspects can be considered according to the variables in the objective function, and the corresponding constraints can be designed, so as to establish a mathematical model of the actual problem. .

在系统层面的控制中,优化算法是控制的核心;对于所涉及的柔性互联系统的优化算法,解决的问题是在柔性互联系统中,控制配网间功率交互,实现系统整体全局优化;而这个问题的是多变量问题,而各变量间独立性较强,且各变量的单调性并不单一;因此,在进行系统优化时,会产生许多局部最优解,算法往往陷入局部最优区间;为此,选择模拟退火优化算法结合牛顿-拉夫逊潮流算法作为系统层面的控制算法;该算法的一大特点就是能够一定概率的跳出局部最优区间,适合多端柔性互联系统的优化算法;其算法框图如图10所示。In the control at the system level, the optimization algorithm is the core of the control; for the optimization algorithm of the flexible interconnected system involved, the problem to be solved is to control the power interaction between the distribution networks in the flexible interconnected system to achieve the overall global optimization of the system; and this The problem is a multi-variable problem, and the independence of each variable is strong, and the monotonicity of each variable is not single; therefore, when the system is optimized, many local optimal solutions will be generated, and the algorithm often falls into the local optimal interval; To this end, the simulated annealing optimization algorithm combined with the Newton-Raphson power flow algorithm is selected as the control algorithm at the system level; a major feature of this algorithm is that it can jump out of the local optimal interval with a certain probability, which is suitable for the optimization algorithm of multi-terminal flexible interconnected systems; its algorithm The block diagram is shown in Figure 10.

本发明基于柔性互联化配电网,建立分层分布式控制,改善柔性互联化配电网的运行;该方案一方面能够从系统整体的层面考虑,进行全局的运行优化控制;另一方面能够从局部的配电网层面考虑,仅通过本地的信息,进行局部电压质量的改善与功率平衡;并且能够在系统层面的控制与本地层面的控制之间灵活无缝切换,从而实现了对配电系统的灵活控制,减小了线路损耗,改善了配电馈线电压质量,提高了配电网运行的经济性与灵活性。Based on the flexible interconnected distribution network, the present invention establishes layered distributed control to improve the operation of the flexible interconnected distribution network; on the one hand, the scheme can be considered from the overall level of the system to carry out global operation optimization control; on the other hand, it can Considering the local distribution network level, local voltage quality improvement and power balance can be performed only through local information; and it can be flexibly and seamlessly switched between system-level control and local-level control, thus realizing the distribution of power distribution. The flexible control of the system reduces the line loss, improves the voltage quality of the distribution feeder, and improves the economy and flexibility of the operation of the distribution network.

实施例2Example 2

参照图11-14为本发明另一个实施例,为对本方法中采用的技术效果加以验证说明,本实施例采用具体实例对本发明方法进行测试,以科学论证的手段验证本方法所具有的真实效果。11-14 is another embodiment of the present invention, in order to verify and explain the technical effect adopted in this method, this embodiment adopts specific examples to test the method of the present invention, and verifies the real effect of this method by means of scientific demonstration .

为了验证柔性互联系统级运行优化控制对配电网系统整体运行的优化作用,本实施例设计了如下算例用于对比分析,算例由独立的两个配电网线路组成,每条馈线接有光伏并网及用户负荷,两条线路的线路阻抗不同,并经直流侧柔性互联,如图11所示。In order to verify the optimal effect of the flexible interconnected system-level operation optimization control on the overall operation of the distribution network system, the following example is designed for comparative analysis in this embodiment. The example consists of two independent distribution network lines, and each feeder is connected to With photovoltaic grid-connected and user load, the two lines have different line impedances and are flexibly interconnected through the DC side, as shown in Figure 11.

算例中线路1的三个节点的负荷分别为24+j18 KVA、-50kW、 24+j18 KVA,线路2的三个节点的负荷分别为20+j15 KVA、-30kW、 20+j15 KVA,线路1与线路2的额定电压为220V,归一化时,各配电网电压的上下限分别设置为额定电压的110%和90%,线路1的线路阻抗是线路2的两倍。In the calculation example, the loads of the three nodes of line 1 are 24+j18 KVA, -50kW, 24+j18 KVA, and the loads of the three nodes of line 2 are 20+j15 KVA, -30kW, 20+j15 KVA, respectively. The rated voltage of line 1 and line 2 is 220V. When normalized, the upper and lower limits of the voltage of each distribution network are set to 110% and 90% of the rated voltage, respectively. The line impedance of line 1 is twice that of line 2.

经过智能优化算法检索后,得到最佳工况,其输出结果如下:After retrieval by the intelligent optimization algorithm, the optimal working condition is obtained, and the output results are as follows:

线路1:Pc1=15960W,Qc1=-20000Var;Line 1: P c1 =15960W, Q c1 =-20000Var;

线路2:Pc2=-15960W,Qc2=-20000Var;Line 2: P c2 =-15960W, Q c2 =-20000Var;

线路损耗由14584W降低至5095W。Line loss is reduced from 14584W to 5095W.

通过仿真验证本发明的控制效果;仿真时序为:t=0s时,仿真启动,本地层面控制的有通讯二次调压按照接受系统层面控制的功率指令,线路 1、线路2均开启至本地层面控制的有通讯二次调压;t=1.5s时,模拟通讯线路中断,系统层面的控制关闭,本地层面的控制切换至无通讯的一次调压;t=2.5s,仿真结束。The control effect of the present invention is verified by simulation; the simulation sequence is: when t=0s, the simulation starts, the communication secondary voltage regulation controlled by the local level is based on the power command controlled by the system level, and both line 1 and line 2 are turned on to the local level. The control is the secondary voltage regulation of communication; when t=1.5s, the analog communication line is interrupted, the control at the system level is turned off, and the control at the local level is switched to the primary voltage regulation without communication; t=2.5s, the simulation ends.

仿真结果如图12-14所示;图12-14分别为线路1、线路2的有功功率、无功功率传递波形图、线路1、线路2中各节点的电压水平、线路1、线路2中换流器电流的dq轴分量。The simulation results are shown in Figure 12-14; Figure 12-14 is the active power and reactive power transfer waveforms of line 1 and line 2, the voltage levels of each node in line 1 and line 2, and the voltage levels of line 1 and line 2. dq-axis component of the inverter current.

分析仿真结果,如图12所示的仿真结果,0.5s~1.5s时,系统投入二次调压控制,线路1向直流侧传递16kW有功功率,线路2从直流侧吸收 16kW有功功率;1.5s时,馈线间通讯中断,系统从二次调压切换至一次调压;1.5s~2.5s时,系统不再接受系统层面控制输出的功率指令,而是根据线路末端的本地电压信息进行控制;此时,线路1向直流侧传递24kW有功功率,线路2从直流侧吸收24kW有功功率。Analyze the simulation results, as shown in Figure 12, when the system is put into secondary voltage regulation control from 0.5s to 1.5s, line 1 transmits 16kW active power to the DC side, and line 2 absorbs 16kW active power from the DC side; 1.5s When the communication between the feeders is interrupted, the system switches from the secondary voltage regulation to the primary voltage regulation; from 1.5s to 2.5s, the system no longer accepts the power command output by the system level control, but controls according to the local voltage information at the end of the line; At this time, line 1 transmits 24kW of active power to the DC side, and line 2 absorbs 24kW of active power from the DC side.

如图13所示的仿真结果,线路1与线路2的无功功率传递情况基本重合;0.5s~1.5s时,系统采用本地层面控制无通讯的二次调压,线路1、线路2吸收20kVar无功功率;1.5s时,系统从二次调压切换至一次调压; 1.5s~2.5s时,系统不再接受系统层面控制输出的功率指令,线路1与线路 2的无功功率稳定在0Var。The simulation results shown in Figure 13 show that the reactive power transfer conditions of line 1 and line 2 basically coincide; during 0.5s to 1.5s, the system uses the local level to control the secondary voltage regulation without communication, and line 1 and line 2 absorb 20kVar Reactive power; at 1.5s, the system switches from secondary voltage regulation to primary voltage regulation; at 1.5s to 2.5s, the system no longer accepts the power command from the system level control output, and the reactive power of line 1 and line 2 is stable at 0Var.

在图14所示的线路1各节点电压水平中:系统不加控制时,节点1、节点2、节点3的电压均未越限,但节点3的电压处于较低水平,且节点 1、节点2、节点3的电压都未达到额定电压水平;系统投入本地层面控制的无通讯一次调压时,相较于无控系统,各个节点的电压有一定的抬升,距离额定电压水平更近;系统接收系统层面控制的功率指令,投入本地层面控制的有通讯二次调压时,各个节点的电压水平有很大的提升,距离额定电压最近。尤其是节点3的电压,亦即线路1末端电压,具有明显的改善。In the voltage level of each node of line 1 shown in Figure 14: when the system is not controlled, the voltages of node 1, node 2 and node 3 are not over the limit, but the voltage of node 3 is at a low level, and the voltage of node 1, node 3 2. The voltage of node 3 has not reached the rated voltage level; when the system is put into the non-communication primary voltage regulation controlled by the local level, the voltage of each node has a certain rise compared with the non-controlled system, which is closer to the rated voltage level; the system When receiving the power command controlled by the system level and putting it into the communication secondary voltage regulation controlled by the local level, the voltage level of each node is greatly improved, and it is the closest to the rated voltage. In particular, the voltage at node 3, ie the voltage at the end of line 1, is significantly improved.

线路2各节点电压水平中:系统不加控制时,节点1、节点2的电压未越限,且与额定值的偏差较大,而节点3的电压低于0.9p.u.,处于低压越限,电压质量问题严重;系统投入本地层面控制的无通讯一次调压时,节点3的电压抬升了25.6V,且处于0.9p.u.~1.1p.u.范围内;并且各个节点的电压水平都有所改善;系统接收系统层面控制的功率指令投入本地层面控制的二次调压时,各个节点的电压水平与一次调压控制电压水平相近,同样解决了线路2末端电压质量问题,改善了整体的电压水平。In the voltage level of each node of line 2: when the system is not controlled, the voltage of node 1 and node 2 does not exceed the limit, and the deviation from the rated value is large, while the voltage of node 3 is lower than 0.9p.u. The quality problem is serious; when the system is put into the one-time voltage regulation without communication controlled by the local level, the voltage of node 3 is raised by 25.6V, and is in the range of 0.9p.u.~1.1p.u.; and the voltage level of each node has been improved; the system receiving system When the level-controlled power command is put into the local level-controlled secondary voltage regulation, the voltage level of each node is similar to the primary voltage regulation control voltage level, which also solves the voltage quality problem at the end of line 2 and improves the overall voltage level.

由上可知,在柔性互联化配电网中,分层分布式控制能够改善了配电网中,馈线负荷不均衡、线路末端电压质量低、线路损耗高等问题,提高了配电网的供电可靠性与运行灵活性。It can be seen from the above that in the flexible interconnected distribution network, hierarchical distributed control can improve the problems of unbalanced feeder load, low voltage quality at the end of the line, and high line loss in the distribution network, and improve the reliability of the power supply of the distribution network. performance and operational flexibility.

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限制,尽管参照较佳实施例对本发明进行了详细说明,本领域的普通技术人员应当理解,可以对本发明的技术方案进行修改或者等同替换,而不脱离本发明技术方案的精神和范围,其均应涵盖在本发明的权利要求范围当中。It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be Modifications or equivalent substitutions without departing from the spirit and scope of the technical solutions of the present invention should be included in the scope of the claims of the present invention.

Claims (9)

1.一种柔性钻石型配电柔性互联变换器分层分布式控制方法,其特性在于,包括:1. A layered distributed control method for a flexible diamond-type power distribution flexible interconnection converter, comprising: 建立基于配电互联变换器的柔性互联化配电网的网架结构;Establish the grid structure of the flexible interconnected distribution network based on the distribution interconnection converter; 基于所述网架结构并分别根据三个层级控制的结构及原理构建分层分布式控制策略,实现对柔性互联配电系统的潮流控制。Based on the grid structure and respectively according to the structure and principle of the three-level control, a layered distributed control strategy is constructed to realize the power flow control of the flexible interconnected power distribution system. 2.如权利要求1所述的柔性钻石型配电柔性互联变换器分层分布式控制方法,其特征在于:所述网架结构包括将各个多互联变换器配置在配电馈线末端,通过所述多互联变换器间的直流母线进行互联。2. The layered distributed control method for flexible diamond-type distribution flexible interconnected converters as claimed in claim 1, characterized in that: the grid structure comprises that each multi-interconnected converter is arranged at the end of the distribution feeder, The DC bus between the multi-interconnected converters is interconnected. 3.如权利要求1所述的柔性钻石型配电柔性互联变换器分层分布式控制方法,其特征在于:所述三个层级包括换流器、本地、系统级三个层面。3 . The layered and distributed control method for flexible diamond-type distribution flexible interconnection converters according to claim 1 , wherein the three levels include three levels of converter, local level, and system level. 4 . 4.如权利要求3所述的柔性钻石型配电柔性互联变换器分层分布式控制方法,其特征在于:所述换流器层面的控制原理包括,4. The layered distributed control method for flexible diamond-type power distribution flexible interconnection converters as claimed in claim 3, characterized in that: the control principle at the converter level comprises: 定义三相电压型PWM整流器作为交直流换流器,其经过坐标变换的数学模型为:Defining a three-phase voltage-type PWM rectifier as an AC-DC converter, its mathematical model after coordinate transformation is:
Figure FDA0003300815460000011
Figure FDA0003300815460000011
其中,ed,eq为交流电压源电压dq轴分量,id,iq为三相交流电流dq轴分量,电阻R与电感L是交流侧主电路中的电感与电阻,vdc为直流侧电压,sd,sq为开关函数的dq轴分量,C为直流电容,RL负载电阻;Among them, ed , e q are the dq -axis components of the AC voltage source voltage, id , i q are the dq -axis components of the three-phase AC current, the resistance R and the inductance L are the inductance and resistance in the main circuit of the AC side, and v dc is the direct current side voltage, s d , s q are the dq-axis components of the switching function, C is the DC capacitance, and R L is the load resistance; 定义所述交流侧电感L与直流侧电容C为:The AC side inductance L and the DC side capacitance C are defined as:
Figure FDA0003300815460000012
Figure FDA0003300815460000012
Figure FDA0003300815460000013
Figure FDA0003300815460000013
式中,Em为电网相电动势,Ts为开关周期,vdc为直流电压,Im为交流基波相电流,Δimax为电流最大允许脉动量,取20%Im,Timax为最大惯性时间常数,ΔPL,max为负载功率最大变化量,Δvdc,max为直流电压最大变化量,
Figure FDA0003300815460000021
为限定直流电压上升时间,RLe为额定直流负载电阻,Idm为额定直流电流,vd0为直流电压稳态最低值,vde为直流电压额定值;
In the formula, Em is the grid phase electromotive force, T s is the switching period, v dc is the DC voltage, Im is the AC fundamental phase current, Δi max is the maximum allowable current ripple, take 20% of I m , and T imax is the maximum Inertia time constant, ΔP L, max is the maximum variation of load power, Δv dc, max is the maximum variation of DC voltage,
Figure FDA0003300815460000021
In order to limit the DC voltage rise time, R Le is the rated DC load resistance, I dm is the rated DC current, v d0 is the steady-state minimum value of the DC voltage, and v de is the rated value of the DC voltage;
在控制中引入PI控制器,将所述PI控制器的增益参数定义为:A PI controller is introduced into the control, and the gain parameter of the PI controller is defined as:
Figure FDA0003300815460000022
Figure FDA0003300815460000022
其中,Ts为PWM开关周期,KPWM为整流桥等效增益,与调制方式有关,KP、KI分别是PI调节器的比例环节和积分环节的增益系数;Among them, T s is the PWM switching period, K PWM is the equivalent gain of the rectifier bridge, which is related to the modulation method, and K P and K I are the gain coefficients of the proportional link and the integral link of the PI regulator, respectively; 将控制环的闭环传递函数简化为一个惯性环节:Simplify the closed-loop transfer function of the control loop to an inertial link:
Figure FDA0003300815460000023
Figure FDA0003300815460000023
5.如权利要求3所述的柔性钻石型配电柔性互联变换器分层分布式控制方法,其特征在于:所述本地层面的控制原理包括一次调压控制和二次调压控制。5 . The layered and distributed control method for flexible diamond-type distribution flexible interconnection converters according to claim 3 , wherein the control principles at the local level include primary voltage regulation control and secondary voltage regulation control. 6 . 6.如权利要求5所述的柔性钻石型配电柔性互联变换器分层分布式控制方法,其特征在于:所述一次调压控制包括,6. The layered distributed control method for flexible diamond-type power distribution flexible interconnection converters according to claim 5, wherein the primary voltage regulation control comprises: 建立下垂方程,归一化方程及经过归一化后的下垂方程为::The sag equation is established, the normalized equation and the normalized sag equation are:
Figure FDA0003300815460000024
Figure FDA0003300815460000024
Figure FDA0003300815460000025
Figure FDA0003300815460000025
Pac1=P1+Pdc1 P ac1 =P 1 +P dc1 控制交流侧归一化电压与直流侧归一化电压相等,即:The normalized voltage of the control AC side is equal to the normalized voltage of the DC side, namely:
Figure FDA0003300815460000026
Figure FDA0003300815460000026
Figure FDA0003300815460000027
Figure FDA0003300815460000027
……...
Figure FDA0003300815460000028
Figure FDA0003300815460000028
定义各条线路的直流归一化电压相等,为:It is defined that the DC normalized voltage of each line is equal, as:
Figure FDA0003300815460000029
Figure FDA0003300815460000029
联立以上式子,经过本地层面控制的一次调压后,可以得到:Combining the above formulas, after a voltage regulation controlled by the local level, we can get:
Figure FDA0003300815460000031
Figure FDA0003300815460000031
Figure FDA0003300815460000032
Figure FDA0003300815460000032
其中,N表示有N个配网柔性互联,Z1,...,Zn分别为第1,...,n个配网的线路阻抗,P1,...,Pn分别为第1,...,n个配网的负载功率,Vac1,...,Vacn分别为第1,...,n个配网的线路末端电压,Pc1,...,Pcn分别为第1,...,n个配网的交直流变换器传递的有功功率,Qc1,...,Qcn分别为第1,...,n个配网的交直流变换器传递的无功功率,Pdc为直流源或荷的功率。Among them, N represents that there are N flexible interconnections of distribution networks, Z 1 , ..., Zn are the line impedances of the first, ..., n distribution networks, respectively, P 1 , ..., P n are 1 , . _ are the active power delivered by the AC-DC converters of the 1st, ..., n distribution networks, respectively, Q c1 , ..., Q cn are the AC-DC converters of the first, ..., n distribution networks, respectively Transmitted reactive power, P dc is the power of the DC source or load.
7.如权利要求5所述的柔性钻石型配电柔性互联变换器分层分布式控制方法,其特征在于:所述二次调压包括,7. The layered distributed control method for flexible diamond-type distribution flexible interconnection converters according to claim 5, wherein the secondary voltage regulation comprises: 在所述一次调压的基础上,定义有功功率与无功功率传输为给定值,即控制各馈线的功率传递为给定值
Figure FDA0003300815460000033
则各线路的下垂方程变为:
On the basis of the primary voltage regulation, the transmission of active power and reactive power is defined as a given value, that is, the power transmission of each feeder is controlled to a given value
Figure FDA0003300815460000033
Then the droop equation of each line becomes:
Figure FDA0003300815460000034
Figure FDA0003300815460000034
Figure FDA0003300815460000035
Figure FDA0003300815460000035
……...
Figure FDA0003300815460000036
Figure FDA0003300815460000036
稳态时,功率与电压方程满足:At steady state, the power and voltage equations satisfy:
Figure FDA0003300815460000037
Figure FDA0003300815460000037
系统满足:The system satisfies:
Figure FDA0003300815460000038
Figure FDA0003300815460000038
各线路经柔性互联后,定义各条线路的直流归一化电压相等,为:After each line is flexibly interconnected, the DC normalized voltage of each line is defined to be equal, which is:
Figure FDA0003300815460000039
Figure FDA0003300815460000039
联立以上式子,可以得到:Combining the above equations, we can get:
Figure FDA00033008154600000310
Figure FDA00033008154600000310
Figure FDA00033008154600000311
Figure FDA00033008154600000311
8.如权利要求3所述的柔性钻石型配电柔性互联变换器分层分布式控制方法,其特征在于:所述系统层面的控制原理包括,8. The layered distributed control method for flexible diamond-type distribution flexible interconnection converters as claimed in claim 3, wherein the control principle at the system level comprises: 根据系统采集的各节点的电压信息及功率信息,通过智能算法的检索,计算得到系统的最优运行状态。According to the voltage information and power information of each node collected by the system, the optimal operating state of the system is calculated through the retrieval of the intelligent algorithm. 9.如权利要求8所述的柔性钻石型配电柔性互联变换器分层分布式控制方法,其特征在于:还包括,9. The layered distributed control method for flexible diamond-type distribution flexible interconnection converters as claimed in claim 8, characterized in that: further comprising: 根据一般数学模型建立实际问题的数学模型,所述一般数学模型为:The mathematical model of the actual problem is established according to the general mathematical model, and the general mathematical model is: min f=f(x,u)min f=f(x, u) {s.t.g(x,u)=0{s.t.g(x, u) = 0 h(x,u)≤0h(x, u)≤0 其中,f(x,u)是目标函数,g(x,u)和h(x,u)分别为等式约束和不等式约束,x、u分别为控制变量和状态变量。Among them, f(x, u) is the objective function, g(x, u) and h(x, u) are equality constraints and inequality constraints, respectively, and x and u are control variables and state variables, respectively.
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