C. Pisani

Dynamic Line Rating monitoring in WAMS: Challenges and practical solutions

The paper addresses the problem of Dynamic Line Rating (DLR) estimation for OverHead transmission Lines (OHLs) in the context of Wide Area Monitoring Systems (WAMSs). DLR is universally recognized by experts from academia and industry as one of the most viable solution for a reliable exploitation of the real power systems thermal loadability margins. In this domain, the large quantity of synchronized data acquired by WAMSs allows to design effective solution frameworks for DLR assessment. To address this issue, various technical challenges, and many open problems, mainly deriving by the non-idealities characterizing the real working domain, should be fixed. Armed with such a vision, this paper, starting from a comprehensive analysis of the role of synchronized data in OHL DLR estimation, proposes practical and viable solutions aimed at addressing some of the open problems in WAMS based DLR. Experimental findings obtained from in-field investigations on a real life OHL, are presented and discussed in order to prove the effectiveness of the proposed techniques.

An optimised methodology to predict the wind farms production

Renewable energy sources (RES), are widely recognized as an effective solution to face with the rapid depletion of oil resources and an interesting energy option to ensure the energy supplies security and the meeting of the targets imposed by the international regulatory frameworks devoted to contrast the global warming. Wind energy source is undoubtedly one of the primary energy source able to provide a significant contribution to the fulfillment of the load curve. Nonetheless, wind energy source is one of the most challenging to predict due to the (i) high level of uncertainty and randomness of the physical phenomenon, (ii) strong dependence on the site topography, (iii) high non-linearity of the involved processes. The massive penetration of wind farms in the existing electrical power systems hence sensibly affects the related secure operation. To provide a solution at the above issue, the present paper aims at the development of an advanced methodology for estimating the wind farms producibility and for characterizing locally the predictions of European Center for Medium-Range Weather Forecasts (ECMWF) model or equivalently the ones of the Consortium for Small-scale Modeling (COSMO). The ingredients which makes the developed methodology optimal are high resolution digital terrain models, proper lateral boundary conditions provided by COSMO-I2 model, optimized wind generation curves derived by the application of statistical identification techniques on wind speed-power. The research activities are included in a research project with the partnership of the Italian TSO, TERNA, and the Italian Center for Aereospatial Research, CIRA.

An advanced system for power supply and power quality improvement of isolated AC passive network

The paper presents an advanced solution for power supply and power quality improvement of isolated AC passive networks. The embedded system consists of a Self-Excited Induction Generator (SEIG) and a Static Var Compensator (SVC) specifically designed for the considered application domain. The SVC is composed by two legs and with an LC filter is linked to the three phase passive network. A proper SVC control strategy is devised and applied on a test system in order to verify its effectiveness in:(i) enhancing power quality, (ii) improving the power system stability as whole, (iii) minimizing the effects of unbalanced loads.

Conceptualization and Experimental Deployment of an Adaptive Synchronized Sensing System for Power Line Thermal Monitoring

Synchronized sensing offered by wide area measurement systems (WAMSs) enables advanced investigations on modern electrical power systems not performable before their advent. One of them is overhead lines (OHL) temperature monitoring, which can be implemented in WAMS industrial domains thanks to the availability of newly accessible sensing information provided by phasor measurement units (PMUs). To accomplish this task, a proper sensing-based integrated intellectualization is necessary in order to face with the major WAMS issues and challenges. In line with these considerations, this paper proposes an advanced computing framework for real-time conductor temperature monitoring of fully transposed OHLs that is able to overcome the aforementioned challenges and issues. The validity and effectiveness of the conceptualized solution is verified via field tests on an Italian transmission line currently in operation. The obtained outcomes led the Italian Transmission System Operator (TSO) to equip its own Energy Management System (EMS) with the deployed solution.

Stator current signature analysis for fault diagnosis in permanent magnet synchronous wind generators

Inter-turn short circuit faults are the most common stator winding faults in permanent magnet wind generators. Their early detection is vital to avoid subsequent damages which can led to catastrophic machine failures. To accomplish this task stator current signature analysis has been recently proposed for identifying inter-turn faults via a non-invasive, non-destructive and cost effective approach. Since no best stator current signature analysis approach is recognized as optimal, the paper takes in consideration the one able to offer the minimum severity degree which is Hilbert Huang Transform. To propose some improvements of the latter in stator current signature analysis, a real 60 kW-25 rpm permanent magnet wind generator is firstly designed via finite element based approach in FLUX® environment. Then SCSA in faulty conditions is performed via proprietary software highlighting how the introduced modifications could further enhance the signal processing algorithm performance.

A dynamic equivalencing preliminary study on ENTSO-E CESA power system

The paper deals with the issue of achieving a dynamic equivalent for large scale power systems with particular reference to the European Network of Transmission System Operators for Electricity (ENTSO-E) Continental Synchronous European Area (CESA). In this paper some essential aspects of the dynamic reduction process are deepened while others are faced according some practical considerations, in some cases derived from other studies in ENSTO-E community. Broadly speaking therefore, it deals with a preliminary study which leads to the deployment of a reduced order model able to describe the electromechanical phenomena occurring on the European Continental Synchronous network.