G. Artale, A. Cataliotti, G. Caravello, V. Cosentino, D. Di Cara, S. Guaiana, N. Panzavecchia, G. Tine

Abstract – This paper proposes a virtual tool for load flow analysis in energy distribution systems of micro-grids. The solution is based on a low-cost measurement architecture, which entails low-voltage power measurements in each secondary substation and a voltage measurement at the beginning of the medium voltage (MV) feeder. The proposed virtual tool periodically queries these instruments to acquire the measurements. Then, it implements a backward–forward load flow algorithm, to evaluate the power flow in each branch and the voltage at each node. The virtual tool performances are validated using power measurements acquired at the beginning of each MV feeder. The uncertainties on each calculated quantity are also evaluated starting from the uncertainties due to the used measurement instruments. Moreover, the influence of the line parameter uncertainties on the evaluated quantities is also considered. The validated tool is useful for the online analysis of power flows and also for planning purposes, as it allows verifying the influence of future distributed generator power injection. In fact, the tool is able to off-line perform the load flow calculation in differently distributed generation scenarios. The micro-grid of Favignana Island was used as a case study to test the developed virtual tool.

G. Artale, A. Cataliotti, G. Caravello, V. Cosentino, D. Di Cara, S. Guaiana, N. Panzavecchia, G. Tine

To promote regulation strategies and incentives for harmonic mitigation, simple tools are needed for
evaluating harmonic pollution levels at point of common coupling (PCC), as well as on the whole
grid. Starting from IEEE Std. 1459-2010 approach [1] and the common concept of power factor
correction, in [2] the authors have presented a preliminary study, aimed at investigating the possibility
of using power ratio parameters for harmonic emission assessment. Being the formulation of IEEE
Std. 1459 power quantities and related power ratio indicators very simple, the proposed indicators
measurement can be easily integrated in common measurement instruments, thus allowing easily the
assessment of harmonic emissions and related billing/incentives strategies implementation. In this
context, it is important to investigate the measurement uncertainty impact on the evaluation of
considered power ratios (both those defined in IEEE Std. 1459 and the new proposed ones) [2]. To
this aim, the measurement of the considered parameters has been implemented on a PC-based
sampling wattmeter. Starting from the instrumentation accuracies and the correlation analysis,
combined standard uncertainties of power ratio indicators have been evaluated and a comparison has
been made between IEEE Std. 1459 indicators and the newly proposed ones. This research has been
funded by PO FESR Sicilia 2014-2020, Action 1.1.5, Project n. O8000PA90246, Title “Smart grids
per le isole minori” (I-Sole), CUP: G99J1 8000540007.

Artale, G.; Caravello, G.; Cataliotti, A.; Cosentino, V.; Di Cara, D.; Guaiana, S.; Nguyen Quang, N.; Palmeri, M.; Panzavecchia, N.; Tinè, G.

This paper proposes a virtual tool for load flow analysis in energy distribution systems of micro-grids. The solution is based on a low-cost measurement architecture, which entails low-voltage power measurements in each secondary substation and a voltage measurement at the beginning of the medium voltage (MV) feeder. The proposed virtual tool periodically queries these instruments to acquire the measurements. Then, it implements a backward–forward load flow algorithm, to evaluate the power flow in each branch and the voltage at each node. The virtual tool performances are validated using power measurements acquired at the beginning of each MV feeder. The uncertainties on each calculated quantity are also evaluated starting from the uncertainties due to the used measurement instruments. Moreover, the influence of the line parameter uncertainties on the evaluated quantities is also considered. The validated tool is useful for the online analysis of power flows and also for planning purposes, as it allows verifying the influence of future distributed generator power injection. In fact, the tool is able to off-line perform the load flow calculation in differently distributed generation scenarios. The micro-grid of Favignana Island was used as a case study to test the developed virtual tool.

G. Artale, G. Caravello, A. Cataliotti, V. Cosentino, S. Guaiana, D. Di Cara, N. Panzavecchia, G. Tinè

Abstract — The study presented in this paper is aimed at analyzing the measurement uncertainty impact on the evaluation of some power ratio parameters for harmonic emissions assessment based on IEEE Std. 1459-2010 apparent power decomposition. In addition to power factors for line utilization and harmonic pollution levels evaluation defined in the Standard, the study covers also some new parameters, which have been introduced by the authors as IEEE Std. 1459- 2010 power quantities ratios. The measurement of the aforesaid parameters is implemented on a PC-based wattmeter, in order to investigate the measurement uncertainty impact on the evaluation of the power ratios. The obtained results show that, in comparison with IEEE Std. 1459-2010 indicator for harmonic pollution level, better results can be reached with the new power ratios, whose behavior is more similar to the traditional power factors.