Abstract

Background: Integration of solar PV presents various challenges in the power system, one such challenge is the variation in operational characteristics of the distribution system.

Method: Solar PVs are installed at the distribution networks which are unbalanced in nature due to unequal distribution of load in each phase. The operational characteristics of distribution feeder alter with the increasing level of PV penetration, which includes variation in voltage level, power flow direction, change in reactive power and power factor. Such situation causes the distribution network operators (DNO) to face unprecedented challenge to maintain the quality of power. Therefore, there is a crucial need to recognize and quantify the technical impact that solar PV may have on the operation of unbalance distribution system to ensure the good quality and reliability of supply.

In this paper, an 11/0.433 kV realistic rural distribution feeder of Indian utility is modeled to investigate the impacts of PV integration on the operational characteristics. A reformulated 3-phase Newton- Raphson (N-R) power flow algorithm is used for the solar PV integrated unbalance distribution system.

Results: The results show that there are drastic changes in branch current loading, neutral current, power losses and power flow direction after solar PV integration. It is also observed that there is huge variation in bus voltage level, which is controlled by line voltage regulators.

Conclusion: Such investigations are necessary before PV integration to the distribution network, which would help the utility engineers for monitoring, energy management, and planning studies.

Keywords: Grid connected PV systems, integration, 3-phase Newton-Raphson (N-R), 3- phase unbalanced power flow, solar PV, penetration.

Graphical Abstract