Calculation Method of Unbalanced Line Loss in Low-Voltage Distribution Network Considering the Access Mode of Distributed Photovoltaic Generation

doi:10.12204/j.issn.1000-7229.2021.10.014

Abstract

Abstract:

The increasing number of household photovoltaic power generation systems has changed the power flow distribution of the distribution network, and at the same time has a significant impact on the line loss of the distribution network. In order to quantify the operating economy of distributed photovoltaic generation (DPG) connected to the three-phase four-wire low-voltage distribution network, this paper takes the three-phase unbalanced line loss as the research objective, and firstly establishes a balanced and unbalanced line loss calculation models suitable for low-voltage distribution network. By introducing three influencing factors of DPG access mode, location and capacity, the line loss variation model under different DPG access modes is established. A model for estimating the three-phase unbalanced line loss of the active low-voltage distribution network considering the DPG access mode is proposed. This method can be calculated by using both real-time current data and easily collected active power data. The accuracy and feasibility of this method is verified by taking typical parameters of low-voltage distribution network as an example, and the method can provide reference basis for line loss calculation of DPG single-phase and three-phase access to low-voltage distribution network.

Key words: low-voltage distribution network, three-phase unbalance, distributed photovoltaic generation, line loss

CLC Number:

TM76

LIU Keyan, JIA Dongli, WANG Weijia, GENG Guangfei, WEI Chenhao. Calculation Method of Unbalanced Line Loss in Low-Voltage Distribution Network Considering the Access Mode of Distributed Photovoltaic Generation[J]. ELECTRIC POWER CONSTRUCTION, 2021, 42(10): 129-138.

Figures/Tables 8

Fig.1 Variation of feeder current with uniform load distribution

Fig.2 Current distribution of balanced distribution line with DPG three-phase connected

Fig.3 Topology diagram of a low-voltage distribution network in a certain area

Fig.4 Line loss rate of distributed photovoltaic power connected to 380V unbalanced distribution network

Table 1 Comparison of line loss variation of balanced and unbalanced distribution network with DPG three-phase access

Table 2 Rate of line loss when DPG single-phase access node 2%

Table 3 Rate of line loss when DPG single-phase access node 5%

Table 4 Rate of line loss when DPG single-phase access node 8%

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