Development of Electromagnetic Transient Simulation Models for Power Quality Analysis of Distribution Systems

Abstract

SUMMARY Due to the rapid spread of renewable energy power sources in recent years, voltage rise problems in distribution systems caused by reverse power flow from these renewable energy power sources especially from photovoltaic (PV) power generation systems are of great concern. To cope with this kind of problems, conventional voltage regulation devices such as load‐ratio transformers in the substation and step voltage regulators (SVRs) on the distribution line are basically used. If their voltage regulation capability is not sufficient, the power conditioning systems of PV power generation systems may be modified so as to supply reactive power and a static synchronous compensator (STATCOM) may be applied to the distribution system. Therefore, the coordination of these conventional and new voltage regulation devices is necessary for the design of smarter distribution systems, and electromagnetic transient (EMT) simulations of distribution systems with these devices have to be carried out to assess power quality. To this end, the authors have developed EMT simulation models of distribution substations, SVRs and distribution STATCOMs, and they are routinely used for power quality assessment studies. This paper presents these simulation models and a simulation example.

An electromagnetic transient simulation model of grid‐connected inverters for dynamic voltage analysis of distribution systems

“…Figure shows the circuit configuration, which includes a distribution substation with LRT, high‐voltage distribution lines, an SVR, and four PV power plants. Simulation models for the distribution substation, the high‐voltage distribution lines, and the SVR were the same as the models reported in the previous research . These models include control systems for the transformer's tap changer.…”

“…With the recent spread of distributed generators (such as photovoltaics [PV]) connected to power systems by inverters and introduction of power‐electronics‐based voltage compensators (such as static VAR compensator), there are concerns about mutual interference between such devices and existing voltage regulators. In some cases, that may lead to power quality issues . For example, there are reports on a malfunction of tap changers in automatic voltage regulators (step voltage regulator [SVR]) caused by PV power plants .…”

“…The dynamic voltage analysis has to be able to take into account the control characteristics of the existing voltage regulators and inverter‐based generators. For these purposes, electromagnetic transient (EMT) analysis is a useful tool that can exactly simulate the inverter's dynamic characteristics at the waveform level …”