1. Brief Description of current status in ship electrical systems

1.1 Ship electric energy systems

Electric power plant onboard has always been a rather complicated power system, comprising DC and AC subsystems of several operating voltage and frequency levels, especially in sophisticated structures with electric propulsion. The aforementioned complicacy is worsened even further in the All Electric Ship (AES) systems, referring to full electric propulsion and extended electrification of all shipboard installations. On the other hand, similarly to continental grids, several steady- and transient-state phenomena, especially concerning power quality problems, emerge, and their consequences have to be thoroughly studied, analyzed and investigated.
The electric power grid of a ship can be regarded as a small scale, autonomous, industrial type compact power system, although several differences between a conventional continental grid and a shipboard installation can be identified. Some of the special features of ship installations are:

The power system is completely autonomous.

The total power installed per volume unit is large, especially in the electric propulsion applications.

Electric energy is often generated by Diesel generator sets, or by shaft generators which are coupled to the main propulsion engine. Often, the fuel used is the (less costly) Heavy Fuel Oil (HFO).

Referring to prime movers, their relative rotational inertia with respect to electric load demand is fairly small.

The largest amount of energy is demanded by electric motors (acting either as main propulsion or as drivers of auxiliary engines).

The electric power grid is composed of cables of small length (50m – 1000m).

Adopting insulated neutral, i.e. ‘unearthed’ or “IT” system is a common practice.

The metal ship hull is used as a means to provide “ideal earth” for Protective Earthing (PE).

A considerable number or electronic devices installed onboard (automation systems, controllers, navigation systems) are sensitive to power quality and EMI problems provoked, in particular, by the extensive use of power electronics. Hence, the power quality problems are of extreme importance, and have to be analyzed thoroughly.

Power Quality (PQ) problems onboard are of different significance, in comparison to the corresponding problems that occur in a continental power grid. In land, power quality problems may result in problematic production processes, while they may also affect the pricing relations (tariffs applied and penalties) between the utility and its clients. The latter is meaningless onboard, where the most important issue is the uniterruptible operation of the system, and its redundancy. A possible malfunction in a critical load may lead to a total loss of the whole vessel, resulting in possible human casualties and environmental pollution.

1.2 Electric Power Quality (PQ) problems in ship electric energy systems – Current status

In this section, a brief description is presented regarding the PQ problems occurring in these ship sub-systems that will be investigated in the proposed here DEFKALION project.

1.2.1 Shaft generator systems

Shaft generator (SG) systems have been exploited for long due to their appealing advantages, as lower cost of produced electricity, lower maintenance cost, and lower noise levels. However, the schemes currently used have certain disadvantages, as they comprise complicated configurations in order to achieve an identical performance to that of auxiliary generators. Thus, in most cases, a power electronic converter is connected downstream the generator, in order to match the output frequency of the generator with that of the rest of the electric grid. Moreover, currently, a companion synchronous motor is also connected, in order to provide the reactive power of the shaft generator system. This synchronous motor acts as a (rotating) capacitor, as it drives no load, but, still, it increases the total losses and the initial building cost. To our knowledge, no studies have been reported on an optimal exploitation of shaft generation systems via modern power converters, considering both the operational and environmental cost. Such studies should also take into account recent research on the propulsion Diesel Engines, which has elaborated operating scenarios for high efficiency and low emission rates.

1.2.2 Auxiliary Propulsion Systems – Thrusters

Electrically driven auxiliary propulsion systems (also referred to as thrusters), most often with controllable itch propellers, have been introduced in the aft or stern part of several ship types, increasing their maneuverability and collision avoidance capabilities. Thruster electric motors are of high power demand, of the order of 0.5 up to 2.5 ΜW, which increases considerably the electric power demand from the electric power generation set. Moreover, during start-up, the thruster motor -like any other motor- absorbs a high transient “inrush current” (varying, in general, between 4-7 times the rated current), so that its rotor starts rotating. The rotor’s inertia is increased by the submerged propeller; it is underlined that, up to now, no hydrodynamic study of the propeller torque demand during the transient starting state has been performed. Further, during the “inrush current” phenomenon, the thruster motor active and reactive power demands are high, too, while the corresponding “transient power factor” is fairly low, as the reactive power required is significantly higher than in steady-state. This high energy demand at a low power factor cannot be easily covered by the vessel’s generator sets, leading to their possible overloading or even tripping. In addition, as a result of the inrush current, large voltage drops take place in the entire power distribution network, introducing “symmetrical” voltage dips to all three-phases; first studies of this PQ phenomenon have been performed, to our knowledge, only by members of the DEFKALION Research Team (Prof. J. Prousalidis and co-workers).

1.2.3 Pod Propulsion systems

A pod is a propeller propulsion device installed externally to the ship’s hull. The pod system comprises a short propulsion shaft, on which the propulsion electric motor is mounted. In most cases, propulsion is achieved by means of fixed pitch propellers powered by an AC synchronous motor (conventional, permanent magnet, or high temperature superconductive) or asynchronous electric motor, fitted inside the pod. The loadings generated by the pod are extremely complicated; first theoretical hydrodynamic studies on the propeller torque demands during the transient starting state have been performed exclusively by members of the of the DEFKALION Research Team (Prof. G. Politis and co-workers). Due to the problem complexity, a large number of factors and parameters should be taken into consideration (the flow around the fin, the strut, as well as the helicoidal propeller slipstream at all azimuth angles). In addition, the interaction between the propeller and the pod body must be also taken into account. Further, if the forces and moments developed during pod operation are not accurately estimated, the induced loads to the pod bearings and the shaft will not be well assessed either, leading to premature ageing and, eventually, failure of most components, as has been reported recently by Lloyds Register of Shipping – LRS . In particular, amongst the highest failure indices are those of main electric motor parts:

stator windings and core

rotor windings

slip ring electric connectors

These high failure rates are attributed mainly to the high temperature development in windings, leading to excessive overheating stresses, indicating that the motors have not been properly selected according to the stressful conditions they are subject to operate in.

1.2.4 Ship earthing schemes

As it is well known, any earthing scheme is designed so that earth fault situations are faced with minimum adverse consequences. During the last three decades, there has been rather limited research work on the significance of ship electric “earthing” (or “grounding”) philosophies, esp. on the PQ-phenomena. The so-called “unearthed” or “IT” system predominating in all ship buildings is currently being reconsidered, due to the extensive ship electrification, comprising mainly complicated systems such as electric propulsion and power electronic converters operating in High Voltage. On the other hand, with the exception of the work by the team of Prof. Prousalidis, no quantitative analysis has been reported, e.g. a theoretical analysis with predictions of the voltage and current distribution during a fault occurrence (i.e. the injection of single-frequency high valued fault current) throughout the ship’s hull acting as the “earth” of the ship grid. This voltage and current distribution could be computed by analyzing via the Finite Element Method (or equivalent) the ship’s hull, the mesh of which is available by the marine structure design engineers (including any material discontinuities); this could be achieved by adopting the VFD-methodology developed by Prof. Meliopoulos (Visiting Researcher from abroad in the proposed “DEFKALION” project) for inland earthing grids comprising soil and copper mesh.

1.2.5 Protection schemes against lightning

Formerly, it was conceived that due to the metal nature of the ship hull, in case of a lightning strike, no problem could occur (e.g. induced overcurrents or overvoltage spikes). However, several problems (sparks, flashovers, induced currents to sensitive electronic equipment, failures etc) have been recorded, pointing to the need for a more in-depth analysis. The problems (caused by the the injection of multi-frequency high valued lightning current) are attributed to the hull structure made by steel and not copper (as e.g. the Faraday cage approach suggests), as well as several discontinuities, e.g. due to soldering. In USA, the PQ-problems are investigated via pure laboratory experimental approaches, i.e. by performing lightning strikes to ship metal models. It is emphasized that no theoretically based parallel method has been established, e.g. similar to that established for inland grids by Professor Meliopoulos (Visiting Researcher from abroad in the proposed “DEFKALION” project). As the steel ship structure is similar but not identical to the copper meshes of grounding grids applied in continental grids, the synergy of marine and structural design engineers (Professor Samouilides and co-workers) is required.

1.2.6 PQ monitoring and recording systems

Ship Power Management Systems (PMS’s) have significantly evolved in the last decades, with modern SCADA systems installed aboard, which enable the on-line monitoring, recording and control of all equipment and operations in the ship electric grid. However, up to now, this is limited only to the steady-state operation, monitoring the instants equipment is switched on and off; moreover, the power demands of each equipment are not monitored nor recorded. On the other hand, most failures occur during transient state, i.e. when PQ phenomena take place. Consequently, several failures of the electrical equipment cannot be analyzed and explained, as there is no PMS installed with integrated capabilities to monitor and record PQ events, and to assist the system operator in analyzing each operating condition and taking the proper courses of action. It is noted that development, integration within existing ship PMS’s and validation of such a system is cumbersome, esp. if it is based on voltage measuring sensors.

2. Progress beyond the state of the art – Novelties – Synergies – Visiting Researcher

The main novelty of the proposed “DEFKALION” project consists in the thorough investigation of electric Power Quality (PQ) issues occurring in ship systems, and in working out solutions from the energy saving and environmental friendliness point of view. To this end, an inter-disciplinary research plan is proposed, involving the scientific fields of marine engineering, naval architecture, energy systems optimization, and electric power engineering. This is accomplished via the inter-university and inter-departmental co-operation of researchers from two Technical Universities (the National Technical University of Athens, with the School of Naval Architecture & Marine Engineering (S-NAME/NTUA) and the School of Electrical and Computer Engineering (S-ECE/NTUA), as well as the Department of Electrical and Computer Engineering of the University of Patras (UoP) and three Technological Educational Institutes (TEI) of the periphery of Greece (Departments of Electrical Engineering of the TEI’s of Lamia, Larissa and of Kavala). Moreover, the Main Research Team is significantly enriched by the participation of the Visiting Researcher, Professor Athanassios (Sakis) Meliopoulos, of the Georgia Institute of Technology (GaTech), USA. The targets of this large scale project, which are enumerated next, are classified into two groups: main general goals and specific targets.

2.1 Main general goals of “DEFKALION” project

Establish a Centre of Excellence in PQ issues of ship electric energy systems.

In-depth interdisciplinary investigation of complex Power Quality (PQ) problems that influence ship operation, in the light of intense electrification of all ship systems.

Propose solutions for PQ problems, in the light of energy saving and environmental issues.

Design and implementation of a monitoring system for analysis and identification of PQ problems in naval power systems within the framework of improved energy efficiency and by the integration of this system with the existing on board power management tools (Power Management Systems – PMS or Electric Power Management and Control Systems – EPMACS).

Improve the quality of the education provided by Universities, considering the needs of the modern job market for Naval Architecture and Marine Engineering, especially Marine Electrical Engineering, as well as the recent developments and requirements in energy efficiency.

2.2 Specific targets of the proposed “DEFKALION” project

Study of the optimum shaft generator configuration/exploitation, considering fuel cost, fuel consumption, emission rates, optimum performance, production and operation cost.

Study of mitigation practices for PQ problems due to thruster starting and operation.

Study of mitigation practices for PQ problems due to pod operation, especially during maneuvering.

Study of PQ problems due to ship grounding practices.

Study of PQ problems due to lightning strikes directly or nearby ships.

By combining the above items, study and analysis of PQ phenomena during the different types of ship operation (maneuvering, mooring, disembarkation etc) as well as design of an integrated monitoring system for PQ.

3. Εxpected benefits at the local and international level

S-NAME/NTUA will establish a Centre of Excellence (CoE) with a focus on Marine Electrical Power Quality issues, in collaboration with S-ECE/NTUA and UoP. This will be complementary to the CoE already established in S-NAME/NTUA in the area of All Electric Ship (via the MARINELIVE project funded by EU, also co-ordinated by J. Prousalidis). It is noted that young professors from Technological Institutions of the periphery of Greece will participate in the proposed “DEFKALION” project, thus having the opportunity to acquire research experience and expertise in an important emerging research field. The proposed activities will thus be the asset for enhancing the research collaboration (among the beneficiary Institutions) on PQ issues of ship electric energy systems via other projects. The results of this research will be integrated mainly in the curricula of S-NAME/NTUA, which is the only Faculty in Greece dedicated to the education of future engineers of the maritime industry, which is a predominant sector of the Greek economy. The results of the proposed “DEFKALION” project will be directly addressable to the Greek maritime industry, offering tangible conclusive measures on attaining optimum efficiency in ship energy systems, in particular electric power ones. Further, the expertise gained in energy optimization will be implementable to existing ship buildings via retrofitting techniques, leading to minimized operation and maintenance costs. This is substantial for the so-called “unprofitable” liners, which are ships of obsolete technology and poor overall efficiency, subsidized by the Greek Government to connect the (numerous) farthest islands.

4. Work Description – Implementation

The proposed project “DEFKALION” builds on a previous project, already completed successfully, on the “Investigation of Power Quality phenomena in shipboard installations focusing on voltage deviation problems” (funded within the frame of the “PYTHAGORAS-II” funding scheme). “DEFKALION” aims at performing a thorough investigation and analysis of Pοwer Quality (PQ) phenomena during the different types of ship operation, as well as at designing an integrated monitoring system for PQ. The ultimate goal is a greener, safer, more reliable and more economic electrified ship. This target is well aligned, in a synergetic manner, with the “MARINELIVE” project funded by EU (contract No 264057, FP7-CAPACITIES-REGPOT-2010-1, Project Coordinator: John Prousalidis), within the frame of which a Centre of Excellence is formed in the scientific field of “All Electric Ship”.

4.1 WP1 – Project Management

The project activities are coordinated by the Project Coordinator (PC), who is responsible for the management, the proper execution and overall monitoring of the project’s technical and financial aspects. The Coordinator co-operates with the Research Committee of NTUA, which, in turn, co-operates with the corresponding services of the Ministry of Education. Thus, the PC resolves all the technical and financial issues emerging during the execution of the project (contracts, payments, procurements etc).
For the proper execution of the project, the Main Research Team (MRT) is coordinated by a Steering Committee (SC), comprising the PC and the Leaders of the Research Teams (it is noted that the PC is the leader of the first Research Team, too). The SC resolves all the technical problems encountered during the project execution. The Leaders of the Research Team are assigned the coordination of a Work-Package or a Task/Sub-Task, for which their Team is responsible. Hence, they are also responsible for timely releasing the corresponding Deliverables. In particular, the proper execution of a task/sub-task is shouldered by the Research Team to which it is assigned. The other members of the Research Team work to the project execution, following the guidelines of the PC and the head of the Research Team they belong to. They may be assigned to be responsible for the execution of a task (and hence for the coordination of the researchers involved), as well as the timely release of the Deliverables.
Finally, the External Research Team (ERT) co-operates with the members of the MRT. A researcher can be involved in many Work-Packages, co-operating with more than one Research Teams of the MRT.
The coordination of each Work-Package and task/sub-task builds on the good communication among the members of the research teams (exchange of views and research results, monitoring of Deliverables and task execution etc). In case of problems, these are resolved by the Steering Committee. All the members of the Steering Committee communicate with one another on a periodic basis (via telephone and e-mail, and via the official meetings which are foreseen in the budget section). The official communication language is Greek, with English being an alternative.

Deliverable(s) / Milestone(s) Month due
D.1.1.a: 1st Annual Report 12
D.1.1.b: 2nd Annual Report 24
D.1.1.c: 3rd Annual Report 36
D.1.2: Final Report 48
M.1.1: Project kick-off 1

4.2 WP2 – Investigation of PQ problems due to shaft generator operation

T2.1 . Data collection and software upgrade

Available data, which are essential for simulation studies for electric power generation systems in ships, PQ and shaft generator configurations, will be updated. This data (some of which will be collected from maritime enterprises collaborating with NTUA, e.g. from the Angelikoussis Maritime Group) comprise Deliverable 1 (D2.1). Upgrade will also be undertaken for the (already existing) simulation codes that will be used for the purposes of this project: PSCAD, PCOPERA and MOTORCAD (see also the budget section).

T2.2 Investigation of generation configurations and interfaces (electrical/ mechanical) in terms of PQ

Different configurations of electric power generation systems with shaft generators will be studied, including the electrical interface as well as the mechanical connection with the main engine. Due to the similarities of shaft generators with wind turbines, the advances in this area will be explored, exploiting the experience of the Researchers from the electrical engineering domain. Considering that configurations of motor-gen sets that can be used as propulsion motor in case of a failure of the main engine are already commercially available, the potential of enhancing these configurations as secondary propulsion schemes will be studied, too. In this framework, different converter topologies will be studied, taking into account different types and configurations of electric machines (doubly-fed induction, double-winding synchronous, etc., with 4-quadrant converters). PQ problems will be studied, especially voltage profile (reactive power control), harmonics and harmonic filters (passive or active) and switching techniques as well as reverse power and short circuits. Simulation software packages will be used as presented in T2.1.

T2.3 Shaft generator configurations

In the course this action, alternative configurations of shaft generators will be studied, considering the relevant technical and economical aspects under the light of environmental considerations (low emissions, energy savings). The aim of this task is the qualitative and quantitative analysis of the advantages and the disadvantages of these configurations. Important parameters to be considered in this analysis are:
- Effects on the quality and the cost of power onboard (generation cost, frequency, harmonics).
- Effects on main propulsion engine (performance, fuel consumption, emissions, cost of purchasing, operation and maintenance).
Additionally, a scenario of combined use of conventional generators with shaft generators will be studied. In this scenario, the main propulsion engine is set at the optimum operation point (depending on the vessel’s speed), and different alternatives are investigated for the excess power.

Deliverable(s) / Milestone(s)   [Month due]
D.2.1: Updated ship data and upgraded software [4]
D.2.2: Shaft generator alternative configurations  [12]
D.2.3: Power Quality of shaft generator systems and Environmental impact [18]
M.2.1: Procurement of upgraded software licences [4]
M.2.2: Complete exploitation plan of electrical sources  [13]

4.3 WP3 – Investigation of PQ problems due to thruster operation

T3.1 Data collection

Technical data of thruster configurations (electric motors and associated propellers) will be collected. These data are needed to perform accurate calculations for the next tasks.

T 3.2 Hydrodynamic study of the transient propeller torque demand

Transient propeller demand in power will be investigated for the different configurations realized when the propeller begins to turn into water. Hence, an accurate estimation of the demand on mechanic energy will be achieved. This estimation will be used to determine the electric motor requirements in terms of electric power supply. This novel approach will be the joint effort of naval-hydrodynamic and electrical engineers. In collaboration with maritime companies, typical operation scenarios will be determined for maneuvering conditions, including collision avoidance. These scenarios will be used for the calculation of the transient load demand of the thruster. A Computational Fluid Dynamics (CFD) code, based on the Boundary Element Method, developed by a MRT member (Prof. G. Politis) will be used and expanded for the purposes of the above described analysis.

T3.3 PQ analysis of thruster operation

Alternative configurations of motor and speed controllers will be studied considering the propeller and its tunnel. Depending on the type of the motor (induction, dc), the converter type (soft starter or chopper) will be investigated, in order to achieve normal starting up, without excessive inrush current. Considering the results of T3.2 for the propeller power demand, PQ parameters will be estimated (voltage dips, frequency dips, transient starting current, transient active and reactive power demand), using proper simulation software (PSCAD, MATLAB, MotorCAD, PCOPERA). Moreover, the estimated electric energy demand will be also used for assessing associated fuel demands and emission of the generator prime movers.

Deliverable(s) / Milestone(s) Month due
D.3.1: Data collection of thrusters 9
D.3.2: Thruster hydrodynamic loading 18
D.3.3: Power Quality during thruster starting-up 24
M.3.1: Propeller hydrodynamic loading 13

4.4 WP4 – Investigation of PQ problems due to pod operation
T4.1 Hydrodynamic study of energy demand of pod systems
Following an update of the azimuth propulsion mechanism data for the main configurations (electric motors, speed controllers, propellers), this task will focus on the determination of the mechanical energy demand and torque of the electric motor for a number of operating scenarios of pods. These scenarios will be used for the calculation of the load demand of the pod propulsor. Similarly to T3.2, this novel approach will be the joint effort of naval-hydrodynamic and electrical engineers.

T4.2 PQ analysis of pod operation

Using the results of T4.1, PQ analysis of the pod operation will be carried focusing on the simultaneous demand of active and reactive power. Simulation packages MATLAB and PSCAD will be used for this purpose. It is expected that the analysis will demonstrate when overloading takes place; the results will be used in the next task.

Τ4.3 Optimization of pod propulsor electric system in terms of PQ

In this activity, an optimization problem will be set up for the electric part of the pod system (electric motor, converter for speed control). Basic constraints of this problem are:
- For normal course, high performance and high power factor.
- For maneuvering, overloading should not lead to excessive stress that could cause damage.
- The design should meet the requirements for a pod propulsor (high power, low volume, easy access for maintenance etc).
- Low energy demand, leading to energy savings and low emissions of the generator prime movers.

Deliverable(s) / Milestone(s) Month Due
D.4.1: Pod hydrodynamic loading 27
D.4.2: Pod Motor loading profiles 36
D.4.3: Optimized design of electric driven pods 42
M.4.1: Optimized design of pod electric motor 37

4.5 WP5 – Analysis of impact of earthing (grounding) on PQ phenomena

T5.1 Investigation of the impact of grounding on PQ

Using symmetrical component analysis, the impact of the grounding will be analyzed in terms of voltage dip, voltage swell and fault current, especially for the single-phase short circuit case. The results will be used for comparative analysis of the different earthing methods. If necessary, the results will be compared with those of corresponding simulations via MATLAB and/or PSCAD.

T5.2 Electromagnetic analysis in short circuit conditions

The grounding network of the ship will be studied using methodologies that are used in continental power systems. Aim of this study is to improve the protection system operation in short circuit conditions, for the different types of grounding, taking into account the special characteristics of the naval systems. For the solution of the electromagnetic problem, an equivalent network will be developed. The approach will be based on the existing methodology for continental systems developed by a MRT member (Prof. Meliopoulos, Visiting Researcher from abroad), which analyzes the voltage distribution along and across the mesh of the “grounding” means. In the ship case studied in the course of the proposed “DEFKALION” project, the mesh of a ship’s steel hull will be used, exploiting the experience in marine structure design of naval architects (especially Prof. E. Samouilides). The background work for this task will be also used for WP6.

Deliverable(s) / Milestone(s) Month due
D.5.1: Solving the short-circuit electromagnetic problem 18
D5.2: Circuit representation of ship earthing grid in short-circuit 30

4.6 WP6 – Analysis of PQ phenomena due to lightning strikes

T6.1 Data collection

Regulations and standards will be collected regarding lightning striking ships, and the safety risks for humans and vessels. Historic data on lightning (the High Voltage Laboratory of UoP has been collecting such data for a long period), as well as data on the different types of lightning (on or nearby the ship) will be also collected, mainly based on the large database of both High Voltage Laboratories (of NTUA and of UoP) participating in the project.

T.6.2 Study of the interaction between lightning and the ship metal hull in the PQ framework

For the solution of the electromagnetic problem, an equivalent network will be developed. Similarly to WP5, the approach will be based on the existing methodology for continental systems developed by a research team member (Prof. Meliopoulos, Visiting Researcher from abroad), which analyzes the voltage distribution along and across the mesh of the “grounding” means. For the case of the ship that will be studied in the course of “DEFKALION”, the mesh of a ship’s steel hull will be used, exploiting the experience in marine structure design of naval architects (especially Prof. E. Samouilides). The main difference with the work in WP5 is that lightning is considered as an injected current containing a wide spectrum of frequencies, rather than an excitation of single frequency (case of a short circuit). Therefore, the following must be determined:
- The minimum allowed size of the finite elements, which should be lower than the lightning wavelength.
- The validity of the approximations in the wave propagation equation that are usually considered to reduce the complexity of the mathematical problem.
- It is also important to identify the points of discontinuity in the network (joints, changes in the material, etc) due to their impact on wave propagation.

Software PCOPERA will be used for the analysis of this complex problem. Network modeling will be done adopting the methodology of Prof. S. Meliopoulos to the ship case (i.e. steel construction with discontinuities instead of uniform copper construction).

T6.3 Test on a High Voltage Laboratory with a small scale ship model

The aim of these tests is the experimental investigation of the development and striking of a lightning impulse on the external side of the ship or near it. These tests will be carried out in the certified (according to ΕΝ ISO 17025:2005) High Voltage Laboratory of NTUA using small scale metal ship models in a water tank; a sufficient number of 3 metal ship models is prescribed (see the budget section).

Deliverable(s) / Milestone(s) Month due
D.6.1: Information on lightning strikes 24
D.6.2: Solving the lightning problem– circuit representation of ship earthing grid 29
D.6.3: Experiments on ship models 42
M.6.1: Electromagnetic problem in lightning strikes 29
M.6.2: Lightning laboratory tests performance 35

4.7 WP7 – PQ monitoring system

The results of the previous WPs will be used to build a knowledge-database for a PQ monitoring system for ship electric power systems. This monitoring system will be also able to incorporate information about the electric system (significant non-linear loads, harmonic filters, protection systems etc). Data mining (feature extraction) and signal processing methods will be used, in order to design a system that would monitor and evaluate the PQ parameters during operation. The above described system will be tested and validated using measurements taken from an onboard electric system over a long period of time. The combined analysis of measurements from different points in the electrical system will be also investigated especially for overvoltages and voltage dips.

T7.1 Design and installation of PQ measuring system

The PQ measurements are planned to be performed on a LNG carrier (the owner of which, Maran Gas Inc. of I. Angelikoussis Group, has expressed its strong interest for the entire project, see Appendix A), a modern ship building of specific interest for the Greek maritime industry and the Greek economy. An indicative plan of the points of installation of the PQ sensors on the electric circuit (single-line diagram) is presented in Appendix B.

T7.2 Design of monitoring system

The basic elements of this monitoring system will comprise the following:
1. Power Management System
2. Harmonic pollution monitoring
3. Protection system monitoring
4. Overvoltage monitoring

T7.3. Validation test of PQ monitoring system

The system will be integrated into the existing ship Power Management System, and tested onboard via the assistance of PQ measuring equipment that S-NAME/NTUA acquires. For this reason, trips to/and from the ship have been prescribed in the proposed budget.

Deliverable(s) / Milestone(s) Month Due
D.7.1: Power quality measuring system 30
D.7.2: Power quality monitoring system 45
D7.3: Testing results of monitoring system 48
M.7.1: Installation of PQ-measuring devices onboard 26
M.7.2: PQ-monitoring system tests 38

4.8 WP8 – Evaluation of the project – Propositions on resolving PQ problems in ships with extensive electrification

This Workpackage will evaluate the project results and summarize the methods for resolving PQ problems, as outlined in the other workpackages. The corresponding Deliverable will be a compendium for PQ issues on ship electric energy systems.

Deliverable(s) / Milestone(s) Month due
D.8.1: Power Quality for ship electric energy systems 48

4.9 WP 9 – Dissemination of Results

The results of the project will be disseminated to the international and national scientific and maritime community via a series of activities as listed below:

T9.1 Project Webpage (creation and update)

The project results will be published in a dedicated webpage, which will be kept updated on a continuous basis. The webpage will be hosted on the NTUA servers for free (in accordance with NTUA’s policy); any associated costs refer only to person-months.

T9.2.a Poster printing of Interim results

The main interim project results (up to month 18) will be summarized in color poster format, with the associated cost prescribed in the budget section. This printout of the interim results will be distributed during the corresponding dissemination events (see T9.4.a).

T9.2.b Poster printing of Final results

The main project results (up to month 36) will be summarized in poster format, the cost of which is prescribed in the budget section. This printout of the final results will be distributed during the corresponding dissemination events (see T9.4.b).

T9.3 Dissemination to the International Community

The project results will be presented to international scientific fora via papers which will either be presented in International conferences and/or published in peer-reviewed journals. There is an estimate for about 19 publications in conferences, 15 in Europe and 4 overseas. The publication cost to conferences is analyzed in the budget section. Further, it is estimated that the project outcome will include a minimum of 4 journal papers.

The most appropriate International Conferences are:
International Naval Exhibition and Conference-INEC, All Electric Ship Symposium-AES, Electric Ship Technology Symposium-ESTS (all organized biannually). Regarding the advanced issues of electric machines and power electronics, dedicated conferences are the International Conference of Electrical Machines-ICEM, the European Conference on Power Electronics and Applications-EPE and the Power Electronics Specialists Conference –PESC.
The following International journals are the most appropriate to publish the project results:
“The Journal of Marine Engineering & Technology” published by the Institute of Marine Engineering, Science and Technology-IMarEST, and the “Electrical Systems in Transportation” of Institute of Engineering Technology (The Coordinator, John Prousalidis, participates in the editorial Board of both magazines). Further appropriate journals are: IEEE Transactions on Power Electronics, IEEE Transactions on Industry Applications, IEEE Transactions on Magnetics, IET Proceedings – Electric Power Applications.

T9.4a Interim Dissemination to national community

The main interim project results (up to month 18) will be presented during a dedicated event to the national (academic and maritime) community. Posters of T.9.2.α are planned to be distributed on this occasion.

T9.4b Final Dissemination to national community

The main final project results (up to month 36) will be presented during a dedicated event to the national (academic and maritime) community. Posters of T.9.2.b are planned to be distributed on this occasion.

The most appropriate forum for both T9.4a and T.9b is that of the Hellenic Joint Branch of RINA/IMarEST (HJB) , in the Board of which the Project Coordinator participates, or alternatively that of SNAME /Greek section. (They both organize evening events every month, which address the entire Hellenic maritime community). The total estimated cost is prescribed in the budget section.

Deliverable(s) / Milestone(s) Month due
D.9.1: Project webpage 3,6
D.9.2.a: Interim Results Posters 24
D.9.2.b: Final Results Posters 48
D.9.3: Conference and Journal papers 48
D.9.4.a: 1st Dissemination Event 24
D.9.4.b: 2nd Dissemination Event 24
M.9.1: Project web-page 2
M.9.2: 1st Dissemination event 24
M.9.3: 2nd Dissemination event 48

5. Resources to be committed

5.1 Personnel

The Main Research Team is subdivided into four research teams (see also the attached files with the CV’s of the members of the Main Research Team)

1) The Marine Technology Team comprising the following academics:
-Assistant Professor John Prousalidis (Leader, Project-Coordinator S-NAME/NTUA)
-Lecturer Christos Papadopoulos (S-NAME/NTUA)
-Associate Professor Gerassimos Politis (S-NAME/NTUA)
-Professor Emmanouil Samouilides (S-NAME/NTUA)
2) The Energy Saving Team comprising the following academics:
-Professor Christos Frangopoulos (Leader, S-NAME/NTUA)
-Assistant Professor Lambros Kaiktsis (S-NAME/NTUA)
-Lecturer Marios Moschakis (Technological Institute of Larissa)
-Assistant Professor John Dermentzoglou (Technological Institute of Kavala)
3) The Electro-Mechanical Energy Conversion Team comprising the following academics
-Professor Emmanouil Tatakis (Leader, UoP)
-Professor Antonios Kladas (S-ECE,NTUA)
-Lecturer Nikolaos Papanikolaou (Technological Insititute of Lamia)
4) The Electric Overvoltage Team comprising the following academics
-Assistant Professor Eleftheria Pyrgioti (Leader, UoP)
-Professor Ioannis Stathopoulos (S-ECE, NTUA)
-Visiting Researcher- Professor Athanassios Meliopoulos (Georgia Institute of Technology, USA),(see also Appendix D)

This MRT is further extended via external collaborators, mostly specialised post-doc researchers and experienced PhD students

Dr Ioannis Hatzilau (Hellenic Naval Academy, Professor Emeritus)
Dr George Tsekouras (electrical, computer & civil engineer, PhD in electric power demand prediction, Lecturer at Hellenic Naval Academy)
Dr Emmanouil Styvaktakis (electrical engineer, PhD in Power Quality of electric energy systems)
Dr Fotis Kanellos (electrical engineer, PhD in efficient control of electric power systems, NTUA post-doc researcher)
Dr George Antonopoulos (electrical engineer, PhD in control of ship electric propulsion systems, NTUA post-doc researcher)
Dr Ioannis Gonos (electrical engineer, PhD in lightning protection systems)
Dr Vassiliki Kontargyri (electrical engineer, PhD in lightning protection systems)
Ms Fani Assimakopoulou (electrical engineer, PhD student in lightning protection systems)
Mr Elias Sofras (naval architect and marine engineer, PhD student in ship electric system Power Quality) (3.28)
Mr Andreas Skoufis (electrical and computer engineer, NTUA-graduate Student)
Mr Vassilios Tsarsitalidis (naval architect and marine engineer, PhD student in hydrodynamic propulsion systems)
Mr Haris Patsios (electrical engineer, PhD student in electric machinery and power electronics of electrified vehicles)
Mr Panagiotis Kakosimos (electrical engineer, PhD student in electric machinery and power electronics of electrified vehicles)
Mr Chris Boubalos (electronic engineer, specialty in data acquisition systems)
There will also be 4 extra researchers (1 specialized in naval architecture and marine engineering and 3 in electric power engineering) that will be recruited at the project kick-off.

The achievements and the collaboration with international Institutions of most members of the research team is presented in the dedicated “DEFKALION” directory of www.ntua.gr/marine_electrical.

The engagement of each researcher team to the different activities/work-packages fits best their specialty (corresponding to a research area as stipulated by the “Thalis” Call) and is figuratively shown in Appendix C. The salary fees of all researchers have been based upon the official Funding Guidelines of the Research Committee of NTUA and vary according to their experience.

5.2 Hardware and software

In the course of the proposed “DEFKALION” project, the equipment in terms of hardware and software of two Universities and four of their laboratories (High Voltage Labs of NTUA and of UoP, Electric Machines and Power Converters of NTUA and Electromechanical Conversion of Energy of UoP) will be exploited. Moreover, portable PQ-Measuring instruments, like Dranetz BMI PX-5/400, Fluke 434b, LEM2050 of S-NAME/NTUA will be utilized. The Laboratory lightning tests will be performed in the premises of the High Voltage Lab of NTUA (certified according to ΕΝ ISO 17025:2005). The PQ monitoring system will be developed using basic elements (sensors, accumulators, timers etc). Concerning simulation software, the already acquired codes PSCAD, MOTORCAD, FLUX3D, FEMM, PCOPERA, MATLAB will be exploited (PSCAD, PCOPERA and MOTORCAD will be upgraded to the latest version, see budget section).

6. Relevant Research

The project coordinator, professor John Prousalidis, as well as all members of the Research Team, have a long and well accredited experience in the research field they will be engaged in within the framework of “DEFKALION”. This experience is justified by the CV’s of all members of the “DEFKALION” Main Research Team, as well as by their key publications, see also http://www.ntua.gr/marine_electrical. It is noted that “DEFKALION” will continue and study in more depth issues of PQ in ships, which were initially considered in the course of a project funded by the “Pythagoras-II” funding scheme (75% by EU funds and 25% by National Resources) (also co-ordinated by Prof. Prousalidis). Moreover, the proposed research will be aligned with the activities of the “MARINELIVE” project, funded entirely by EU, which aims at establishing a Centre of Excellence to perform research in the scientific area of the “All Electric Ship -AES”. Moreover, members of the 1st Team, MT, have accredited experience in: (a) marine structure analysis (Prof. Samouilides), which is useful for WP5 and WP6; (b) in ship shaft systems (Dr Papadopoulos), useful for WP2; (c) pod and thruster transient hydrodynamic behavior (prof. Politis), useful for WP3 and WP4. Furthermore, all members of the 2nd Team, ES, have a long experience in investigating energy saving strategies and system optimized performance operation from the emissions point of view; this experience will be exploited in WP2, WP3, WP4 and WP7.
Further, all members of the 3rd Team, EMEC, have experience in electric vehicle propulsion, accompanied with experience in design of electric machines (Professor Kladas) or with design of power converters (Prof. Tatakis and Dr Papanikolaou), which is to be exploited in WP2 and WP3. Their experience in coupling wind turbine-generators (of variable speed) with the grid via power converters is to be exploited in WP2, as shaft generators systems have a variable speed, too.
Finally, members of the 4th Team, EO, have experience in studying inland grounding grids, and effects of lightning strikes, esp. in metal structures like wind turbines and communication antennas.