﻿ 分布式电源接入对配电网稳态运行的影响 The Impact of Distributed Generation Access on Steady-State Operation of the Distribution Network

Smart Grid
Vol.05 No.04(2015), Article ID:15836,10 pages
10.12677/SG.2015.54021

The Impact of Distributed Generation Access on Steady-State Operation of the Distribution Network

Xu Zhang1, Hua Gao1, Lijuan Li1, Jianbo Liao2, Zhenkun Li2, Yang Fu2

1Grid Planning Research Center of Guizhou Power Grid Corporation, Guiyang Guizhou

2School of Electric Power Engineering, Shanghai University of Electric Power, Shanghai

Received: Jul. 16th, 2015; accepted: Aug. 8th, 2015; published: Aug. 11th, 2015

ABSTRACT

The gradual depletion of traditional energy and aggravation of environmental pollution makes distributed generation applications increasingly widespread. Distributed generation access has changed the structure of the distribution network and caused a series of effects on steady-state operation of the distribution network. This paper analyzes the power flow calculation of the distribution network including distributed generation and the treatments of various types of distributed generation are given. From three angles of capacity, access location and power factor, a detailed study about the impact of distributed generation access for distribution network voltage and network losses is implemented. Example simulation results show that the capacity of distributed generation shouldn’t be too large, access location should be selected in the center-rear of the feeder, power factor should be as high as possible and for the lag, which are conducive to the stability of distribution network voltage and reduce network losses.

Keywords:Distributed Generation, Distribution Network, Power Flow Calculation, Voltage Influence, Network Loss Influence

1贵州电网公司电网规划研究中心，贵州 贵阳

2上海电力学院电气工程学院，上海

1. 引言

2. 分布式发电及其对配电网的影响分析

2.1. 分布式发电技术

2.2. 分布式发电对配电网的影响

(1)

(2)

3. 含分布式电源配电网的潮流计算

3.1. PQ型DG的处理方法

PQ型DG输出的有功和无功功率为恒定值。只需当作负的负荷处理即可。此时等效节点为：

(3)

3.2. PQ(V)型DG的处理方法

PQ(V)型DG输出的有功功率为恒定值，输出的无功功率与节点电压有关。只需在每次迭代计算出节点电压后，更新DG输出的无功功率即可，其余与PQ型DG的处理方法相同。处理方法为：

(4)

(5)

3.3. PI型DG的处理方法

PI型DG输出的有功功率和电流为恒定值。类似的，在迭代得到节点电压V后，通过算式修正DG输出的无功功率，之后按照PQ型DG的来处理：

(6)

(7)

Table 1. Node type corresponding to various types of DG

3.4. PV型DG的处理方法

PV型DG输出的有功功率和电压为恒定值。传统的前推回代法无法保持节点电压为定值，因此对PV型DG需要进行特殊处理，不断更新DG无功功率以修正节点电压，在迭代得出各节点电压V后，修正方法为[11] ：

(8)

(9)

(10)

(11)

3.5. 计算流程

1) 设置系统支路阻抗、节点负荷等原始参数。

2) 设置DG参数。设各节点初始电压为额定电压；设置PQ型DG的P、Q值；设置PQ(V)型DG的P值，并计算Q值；设置PI型DG的P、I值，计算Q值；设置PV型DG的P、V值和Q初值，生成节点电抗矩阵X。

3) 计算各节点的负荷与DG的总注入电流。

4) 前推计算各支路电流。

5) 回代计算各节点电压。

6) 收敛判断。PV型DG节点以为收敛条件；其余节点以为收敛条件；也可以最大迭代次数为收敛条件。若所有节点均满足收敛条件，则得出潮流解，算法结束；否则进入7)。

7) 无功修正。由新迭代出的各节点电压，更新修正PQ(V)型DG、PI型DG、PV型DG的Q值。并判断PV型DG的Q值是否越限，若越上(下)限，则令Q值等于上(下)限，并将此PV型DG转换为PQ型DG，之后转入步骤3)。

4. 算例与分析

4.1. DG容量对配电网电压和网损的影响

Figure 1. Power flow calculation flow chart of distribution network with DG

Figure 2. IEEE 33 nodes distribution system

Table 2. The change of DG capacity

(a) 电压分布 (b) 系统平均电压偏差

Figure 3. System voltage level corresponding to different DG capacity

(a) 网损分布 (b) 系统总网损

Figure 4. System losses level corresponding to different DG capacity

4.2. DG位置对配电网电压和网损的影响

4.3. DG功率因数对配电网电压和网损的影响

Table 3. The change of DG access location

(a) 电压分布 (b) 系统平均电压偏差

Figure 5. System voltage level corresponding to different DG location

(a) 网损分布 (b) 系统总网损

Figure 6. System losses level corresponding to different DG location

Table 4. The change of DG power factor

(a) 电压分布 (b) 系统平均电压偏差

Figure 7. System voltage level corresponding to different DG power factor

(a) 网损分布 (b) 系统总网损

Figure 8. System losses level corresponding to different DG power factor

5. 结语

The Impact of Distributed Generation Access on Steady-State Operation of the Distribution Network[J]. 智能电网, 2015, 05(04): 172-181. http://dx.doi.org/10.12677/SG.2015.54021

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