• modelling information-control systems of power systems and optimization research.

 

With rapid development of information and communication technologies (ICT), more control and protection automatic equipment, including intelligent electronic devices, is introduced into electric power systems (further EPS). EPS control algorithms are getting more complexity as they must ensure coordinated operation of all those devices for EPS to run in the scheduled mode and properly interact with other EPS. New approaches are undertaken, e.g. GPS (Global Positioning System)- based wide area protection system. It is endeavoured to process more information (telemetering data, telesignals) from different EPS points in real time in order to: 1) generate control solutions that adequately correspond to the EPS status and send the respective commands to remote EPS controllers; 2) select optimal setpoint of automated devices. Here the target is to achieve optimal ratio of the centralised and decentralised control. Flexible alternating current transmission systems (FACTS), i.e. power electronic controllers, are introduced to increase the transferring ability of the network and improve EPS stability. The enhanced control increases cost-effectiveness of EPS, reduces emergency risk, allows for disturbance localization in the national system and enables to avoid its spreading within interconnected system.

 

Calculations of load flows in IEEE 14 bus test system with FACTS controller in
branch 4–5

 

 

Laboratory of Systems Control and Automation carries out research and offers services in the following fields:

• evaluation and analysis of EPS parameters;

• mathematical modelling of EPS, power networks and control systems;

• investigation of advanced EPS control methods, new automatic control devices and ICT applications;

• investigation of EPS control issues and development of control algorithms (related to frequency, active and reactive power control, static and dynamic stability, loss reduction, power quality, emergency prevention, aspects of electricity market);

• EPS and network extension modelling and technical policy formulation;

• cost-effectiveness of power consumption, control and development of EPS and power networks;

• research and assessment of EPS reliability, security and risks;

• optimization of EPS operation under market conditions, development of competitive mechanisms of balancing, system operator and ancillary services;

• assessment of EPS control needs related to integrating into EPS wind power plants, other power plants on renewable energy sources, small-scale generators.

 

 

 

In 2008 Laboratory completed a three-year state-funded project Efficient use of National Balance Control Resources in Lithuanian and Baltic Power Systems. This project corresponded to research area Modelling of complex systems, development of technical measures of their management methods and control. During the project time, efficient use of national balancing resources was analysed aimed at developing effective methods for improvement of EPS operation states and optimal choice and control of generation reserves. Therefore the possibilities of smart control of available generation resources were investigated, including application of advanced approaches and methods (such as FUZZY logics) to provide better automated generation control.

 

Influence of EPS states on system reliability was analysed as well. Herein the causes of accidents, which cut electricity supply to large regions, and their prevention opportunities were gone through. It enables more thoroughly to assess a risk of scheduled EPS state and choose adequate risk reduction measures.

 

The effectiveness of parametric identification and spectrum analysis methods was investigated. It would enable to make more precisely and readily the estimates of EPS dynamic frequency characteristic parameters. Secondly, it assists in getting more information on probable frequency variation process during large emergencies. Finally, it can contribute to the selection of system structure ensuring enhanced system robustness against disturbances.

 

Since the magnitude of EPS imbalance depends on the scale of wind power generation in EPS, the needed reserve capacities have been found for different combinations of wind power generation and disturbances in EPS.

 

In 2008 researchers of the Laboratory performed a number of research projects for customers in the Republic of Lithuania. In accordance with the contract with SC Mažeikių Nafta, one of the largest oil refineries in Central Europe (10 million tons crude oil per year), the following projects were carried out:

 

• Analysis of legal conditions for the connection of new electric equipment of SC Mažeikių Nafta to power networks;

• Development and reconstruction plan of SC Mažeikių Nafta power network;

• Economic efficiency calculations for the development of SC Mažeikių Nafta power network.

 

During implementation of project Analysis of Legal Conditions for the Connection of New Electric Equipment of SC Mažeikių Nafta to Power Networks, the legal and technical opportunities of SC Mažeikių Nafta to connect new electric equipment to transmission networks were examined as well as consistency of legal acts of the Republic of Lithuania regulating the connections and their respect to the interests of a new customer. Recommendations of project experts on connection of new equipment to power networks were presented to SC Mažeikių Nafta.

 

During implementation of project Development and Reconstruction Plan of SC Mažeikių Nafta Power Network, several alternatives of development and reconstruction were proposed, their advantages and disadvantages analysed and preliminary economical comparisons of these alternatives carried out.

 

During implementation of project Economic Efficiency Calculations for the Development of SC Mažeikių Nafta Power Network, overall cost-effectiveness of development alternatives was determined taking into account not only capital investments, but also operation cost of “new network” and electricity losses.

 

In accordance with the contract with SC Lietuvos Energija, the part of project Investigation of Dynamic Regimes of Perspective Lithuanian Power System Scheme for 2025 was accomplished and the following interim results were presented:

 

• Scheme of Lithuanian Power System Development till the Year 2025;

• Development of Mathematical Model of Lithuanian Power System for 2010, 2015, 2025.

 

During implementation of project Scheme of Lithuanian Power System Development till the Year 2025, the perspective scheme of Lithuanian power system the year 2025 was developed. It contains options of deployment of new generation sources as well as options of development of 110–330 kV transmission network up to 2025, with full pictures for intermediate points 2010 and 2015. The options are based on forecasts for generating capacity needs and maximum loads in Lithuanian system.

 

During implementation of project Development of Mathematical Model of Lithuanian Power System for 2010, 2015, 2025, the numerical model of Lithuanian power system (110–330 kV transmission networks) was prepared to perform various electric calculations. The model reflects three time horizons of 2010, 2015 and 2025. New generators and network equipment were taken from the abovementioned project Scheme of Lithuanian Power System Development till the Year 2025 and introduced to the model. The model is designed for static, dynamic and short circuit calculations.

 

 

 

In accordance with the contract with JSC Šilutės Šilumos Tinklai, the project Expertise of Cogeneration Power Plant Connection to Power Networks was carried out. It has examined the fairness and validity of the connection-to-grid technical conditions (issued by the network operator), technical connection project and connection cost.

 

Researchers of the Laboratory participated in international projects. First of them, UNDERSTAND is part of European Commission programme Leonardo da Vinci. The objectives of the project was to identify the “intersystem” cooperation problems in crisis management process, to identify the education needs and to develop a package of attractive education programs for European electricity suppliers, transmission and distribution network operators as well as education institutions that prepare electrical engineers.

 

 

The second international project Bulk Electrical Energy Transport in Europe explains the specificities of power system operations and discusses the most advanced technologies and their advantages and disadvantages, reviews the issues related to operation and development of power systems and highlights the milestones in the development of power systems in the future ensuring:

 

• really functioning electricity market based on strong interconnections;

• extension of usage of renewable energy sources;

• high reliability of power supply.

 

Results of the project are dedicated to European institutions (e.g. European Commission), which are responsible for power sector. The project is co-ordinated by the European Academies Science Advisory Council, which is comprised of national science academies from 26 EU member states. This Council enables its members to undertake joint actions in submitting proposals to EU policy makers.

 

In 2008 results of research were published in 1 article in the journal indexed the list of ISI, 1 article in international journal. Researchers of the Laboratory presented 2 papers at international and 1 at Lithuanian conferences.