分布式电源对配电网电压暂降的影响.pdf

摘要

I

摘 要

人类社会发展的脚步愈来愈快，对地球上各类自然能源如煤、石油等的消

耗日益增多。那么发掘新的可供人们使用的资源，并且将其运用到发电系统中

是现代社会的当务之急。分布式电源（DG）种类众多，在配电网中普遍应用的

是利用风能的风力发电和利用太阳能的光伏发电。在集中发电和大电网运行的

基础上，现代电力系统正逐步向含有分布式电源的新型电网发展。然而，随着

DG 对配电网渗透率不断提高，电网的电压质量不可避免的受到影响，需要引起

式供电系统电压—功率特性展开讨论。对于电压暂降问题，文章列举了三类常

用的电压暂降随机预估方法，并对比后选择蒙特卡罗模拟法。该方法需要建立

故障特征的随机模型，其作用是用来产生随机的故障信息，从而对实际电力系

统进行有效模拟。

文章采取仿真的形式来研究配电网的电压暂降问题以及 DG 接入配电网是

如何造成影响的。按照蒙特卡罗法在 PSCAD 软件中搭建模型，以一个 27 节点

的中压配电网为测试对象，并考虑 DG 在不同类型、容量、接入位置和控制方式

的情况下并网以及故障特征的随机模型，采取电压暂降评估指标即系统平均方

均根值变化频率进行评估。仿真结果表明通过合理调整 DG 在以上四个方面的配

置能够降低电压暂降的发生频次，这为 DG 在配电网中的配置优化和缓解配电网

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Abstract

In modern times, energy resources like coal, natural gas and petroleum are

suffering the crisis of being exhausted when the pace of human society and

technology runs at a high speed. Therefore it is necessary for us to explore and make

use of new resources and to render them as the material that can generate electricity.

Distributed generations or DGs now appear in various forms. And the most widely

used DGs can be summarized as the wind power generation and solar power

power system and figures out how DG affects the voltage quality. Then the models of

DG’s interconnection to the distribution network and two most widely used DGs are

built in this paper. The interconnection forms are synchronous motor, asynchronous

motor and inverter. The wind power generation model consists of two main blocks,

one is the wind speed function model and another is the wind turbine model. The

solar power generation model is made up of the dynamic mathematic interconnection

model and the control strategies of inverter.

After the analysis for DG’s interconnection, this paper proposes the voltage

quality problems and explains the voltage-power properties of distribution network

with DG. When comes into the stochastic evaluation of voltage sag, the paper

Finally this paper employs a simulation tool, namely PSCAD/EMTDC, to

conduct the research of voltage sag problem and DG’s influences. According to

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Monte Carlo method, a test system with 27 nodes is modeled in PSCAD. Then the

simulation process will allow for DG’s different configurations such as types, sizes,

positions and control strategies as well as the stochastic model of faults. The data that

is collected from the process will be calculated into SARFI, an index that can

evaluate the voltage sag. In the end, results show that the frequency of voltage sag

can be alleviated obviously by adjusting the four configurations of DG mentioned

above in right ways. This provides the theoretical references for optimizing the DG

configuration and mitigating the voltage sag in distribution network.

目录

IV

目 录

1.1 题目背景和意义 ............................................................................................ 1

1.2 分布式发电简介 ............................................................................................ 2

1.2.1 分布式电源的概念及特点 .................................................................................... 2

1.2.2 分布式发电的类型 ............................................................................................... 4

1.3 研究现状 ........................................................................................................ 7

1.3.1 国内外分布式发电现状........................................................................................ 7

1.3.2 分布式电源电压质量研究现状 ............................................................................. 8

2.1.3 逆变器型 ............................................................................................................. 16

2.2 风力发电建模 .............................................................................................. 17

2.2.1 风速数学模型 ..................................................................................................... 17

2.2.2 风力机概述 ......................................................................................................... 19

2.3 太阳能光伏发电建模 .................................................................................. 22

2.3.1 光伏并网动态数学模型...................................................................................... 22

2.3.2 光伏逆变器控制方式.......................................................................................... 25

2.4 本章小结 ...................................................................................................... 26

目录

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3.1 电压质量概述 .............................................................................................. 27

4.1 引言 .............................................................................................................. 34

4.2 电压暂降随机预估分析 .............................................................................. 35

4.2.1 电压暂降的随机预估方法 .................................................................................. 35

4.2.2 故障点法 ............................................................................................................. 35

4.2.3 临界距离法 ......................................................................................................... 36

4.2.5 蒙特卡罗模拟法 .................................................................................................. 37

4.3 故障特征随机模型 ...................................................................................... 37

4.4 电能质量指标 .............................................................................................. 39

4.5 本章小结 ...................................................................................................... 40

5.2.2 电压暂降评估流程 ............................................................................................. 46

5.3 仿真结果分析 .............................................................................................. 47

5.3.1 DG 并网方案 ........................................................................................................ 48

5.3.2 DG 类型的影响 .................................................................................................... 49

5.3.3 DG 容量大小的影响 ............................................................................................ 50

5.3.4 DG 控制方式的影响 ............................................................................................ 51