A. Gubina

University of Ljubljana, Faculty of Electrical Engineering, Faculty Member

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Michael Coulon

University of Sussex

Saif Ali

University of Baghdad

Dietmar Maringer

Peter Winker

Justus-Liebig-University Giessen

Alessandra Amendola

Tim Bollerslev

Craig Pirrong

University of Houston

Nadia Scordino

Martin Jermakyan

Rafał Weron

Wrocław University of Technology

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Papers by A. Gubina

Bid-based stochastic model for electricity prices: The impact of fundamental drivers on market dynamics

Energy Laboratory Publications MIT EL 00- …, 2000

The bid based model developed in this report is intended as a fundamental model for electricity p... more The bid based model developed in this report is intended as a fundamental model for electricity price dynamics, to be used in a wide range of applications. The emphasis was placed on incorporating the unique characteristics of electricity prices, including seasonality on multiple time scales, lack of load elasticity, stochastic supply outages, strong mean reversion, and stochastic growth of load and supply. Principal component analysis is applied in the model in order to capture intra-day dynamics, while at the same time greatly reducing the computational complexity. The model is calibrated on actual load and price data form the New England ISO. We also propose extensions of the model to deal with instances of multiple spot markets connected by transmission lines. Through simulations we illustrate how the model can be used to estimate the value of transmission rights in a two-market environment. It is also shown how the model can be used by a for-profit transmission provider in order to make optimal investment decisions in new transmission capacity. Finally, an extension of the model is proposed to simulate the interaction between technical innovation and long-term price dynamics in electricity markets. Index 1 PROBLEM OF INTEREST.

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Energy Based System Well-Being Analysis

2007 IEEE Power Engineering Society General Meeting, 2007

Determination of adequacy in small isolated power systems (SIPS) is important from technical as w... more Determination of adequacy in small isolated power systems (SIPS) is important from technical as well as economic point of view. In this paper, a novel energy-based system well- being analysis framework (EBSWBA) is presented, which overcomes the weaknesses of the SWBA and considers all important factors that influence system adequacy. The framework combines the advantages of SWBA and Energy-Not Served

Demand-side participation in system reserve provision in a stochastic market model with high wind penetration

2012 IEEE International Conference on Power System Technology (POWERCON), 2012

ABSTRACT The complexity and the cost of maintaining power system security using only supply-side ... more ABSTRACT The complexity and the cost of maintaining power system security using only supply-side mechanisms is likely to increase in the future, especially due to the increasing generation from the renewable energy sources. Advances in control and information technology offer a possibility for the demand to participate in the system reserve market. By providing reserve, consumers could maximize their benefits derived from electricity markets. We present a new approach to the stochastic modeling of the demand-side reserve provision in co-optimized electricity and reserve markets in the case of growing wind power production. The proposed stochastic market model was formulated as a linear two-stage mixed-integer stochastic program and accounts for the costs and benefits that consumers derive from participating in the reserve market. It is shown that the contribution of the consumers to the system reserve may be necessary for the in the high wind power production case. The proposed method was tested on IEEE Reliability Test System.

The generation capacity reserve forecasting in power system

2012 9th International Conference on the European Energy Market, 2012

The forecasting of generation capacity reserve through the use of well-being indices provides use... more The forecasting of generation capacity reserve through the use of well-being indices provides useful information for power system operator about power system security and for power traders about generation reserve pricing. Using this information, the system operator can take actions to provide sufficient generation capacity reserve to meet the required levels of the security parameters. In the paper we propose an efficient algorithm by which the probabilities of near-term well-being indices of generation capacity reserve can be identified. The proposed algorithm is based on the second order Markov chain and Monte Carlo simulation outcomes. Through the calculated distribution of probabilities of well-being indices of various generation capacity reserve levels the additional needs in reserve and their price can be analyzed and traded. The proposed approach is tested on the Bosnian power system.

Scheduling the Slovenian cascaded hydro system on the river Sava

IEEE Africon '11, 2011

ABSTRACT Short-term scheduling of a cascade of run-of-river hydro power plants is always a challe... more ABSTRACT Short-term scheduling of a cascade of run-of-river hydro power plants is always a challenge. In the paper, a quadratic programming approach is used to solve this problem for the hydro power plant chain on the Slovenian Sava River. The approach considers head-dependency and discharge ramping constraints and takes the nonlinear connection between the water discharge and, the head and the power generation. The model has been tested using measured data on hydro flows and the technical data on the Sava River power plants.

Provision of operating states for power system simulation via Monte Carlo approach

In the paper, we present a new method for provision of power system operating states, used in pow... more In the paper, we present a new method for provision of power system operating states, used in power flow analysis. Based on partial power system operation information, the method would yield a set of statistically valid initial operating states that is of manageable size. We investigate the viability and the performance impact of the initial power system operating states obtained using the proposed method on power system simulation results, comparing them to the results obtained using reference initial states, based on full system information. The method calculates initial states from statistically-determined parameters derived from historical power system operation data, employing Monte Carlo simulation. A method for heuristic calculation of the historical parameters is discussed and its results evaluated for Slovenian power system. Using thus computed- and the reference initial operating states, a power flow-based calculation of the reference control bands for secondary voltage co...

The Advanced Bidding Strategy for Power Generators Based on Reinforcement Learning

Energy Sources, Part B: Economics, Planning, and Policy, 2014

ABSTRACT Facing the competition in the maturing electricity markets, the power producers have to ... more ABSTRACT Facing the competition in the maturing electricity markets, the power producers have to devise innovative bidding strategies to maximize profits while balancing the costs. In this article a new method for supply bid design based on reinforcement learning of agents is proposed for a thermal power producer. Through their bidding strategies, the producers are following the composite objective function of maximizing profits while maintaining the utilization factor. The performance indicators, which include profit of each unit and its utilization factor, are presented in learning and non-learning scenarios for the Slovenian power system. The results show that the agents that use the reinforcement learning bidding strategy consistently outperform those that use simple non-learning bidding on the electricity market.

The security of electricity supply: The economic downturn's influence in Slovenia

Energy Sources, Part B: Economics, Planning and Policy, 2014

ABSTRACT In every country, one of the most important performance criteria for the electricity sec... more ABSTRACT In every country, one of the most important performance criteria for the electricity sector is the security of the electricity supply. In this article, the influence of the economic downturn on the national security of the electricity supply is analyzed, using the proposed methodology for an integrated assessment of the security of the electricity supply. It is composed of an integrated model, featuring the security of the electricity supply performance indices of the distinct dimensions of a power system. These distinct dimensions are assessed using the best practices available. An aggregated index for measuring the security of the electricity supply is constructed on the basis of three distinct dimensions: the security of the primary energy supply, the environmental performance, and the power system reliability. Using the proposed index, the security of the electricity supply for Slovenia is calculated, before and after the economic downturn, highlighting the key drivers and their influence on the security of the electricity supply.

Power system's security improvement through ANN-based decentralized secondary voltage control

Seminar on Neural Network Applications in Electrical Engineering, 2000

In the paper, issues of electrical power system (EPS) security are investigated. The EPS equipped... more In the paper, issues of electrical power system (EPS) security are investigated. The EPS equipped with a decentralized modular secondary voltage and reactive power control based on artificial neural networks (ANNs) is presented. Each generator is equipped with an automatic secondary voltage controller with ANNs that requires only local measurements for its operation. The ANNs were trained on optimal power

Demand-side system reserve provision in a stochastic market model

Energy Sources, Part B: Economics, Planning, and Policy, 2016

REserviceS D5.5. Ancillary services from wind and solar PV at transmission level - evaluation and conclusions of case studies

This report is part of REserviceS EU project on ancillary services from non-synchronous wind powe... more This report is part of REserviceS EU project on ancillary services from non-synchronous wind power and PV generation (variable generation, VG). In this report results from transmission level ancillary services from VG are summarized from work package 5 case studies: Ireland, Offshore, Iberia and Europe. The work is mainly focusing on frequency support services. Some transmission related voltage support cases have been summarized, but the main voltage related work is performed in WP6 of REserviceS project.

Indicative RES-E targets for the year 2010 and their fulfillment in slovenia

AFRICON 2007, 2007

ABSTRACT To reduce the reliance on imported fossil energy sources and combat climate change, to f... more ABSTRACT To reduce the reliance on imported fossil energy sources and combat climate change, to foster domestic technology development and harmonize the national support policies for renewable energy sources (RES) in its Member States, the European Commission introduced the Directive 2001/77/EC, defining renewable portfolio standards for the Member States. The indicative target for Slovenia is the 33,6 % contribution of RES in total gross electrical energy consumed by 2010. In this study, we review the mid-term possibility of achieving the Slovenian objectives, considering factors crucial for forecasting hydropower production. It is apparent that in order to achieve the RES-support policy goals and to break the spell of their weather-dependency, the support schemes in Slovenia need to be re-assessed and appropriately amended.

Unified Approach to Reliability Assessment in an Isolated RES System

2006 International Conference on Probabilistic Methods Applied to Power Systems, 2006

Due to their unique characteristics, renewable energy sources (RES) are an ideal energy source fo... more Due to their unique characteristics, renewable energy sources (RES) are an ideal energy source for small isolated power systems (SIPS). At the same time, the reliability impacts of RES electricity supply should be carefully studied, especially in SIPS with significant RES installed capacity. One of the most potent methods for this purpose is System well-being analysis, accounting for deterministic and stochastic reliability factors. In the paper, we present a novel method for calculation of system well-being indices based on Contingency enumeration (CE) method. We also investigate the energy-oriented Energy not served (ENS) index and propose an improved method for its calculation. The indices are then used to analyze the impacts of different hybrid generation structures and RES penetration levels on supply reliability of the system. We investigate the suitability of different reliability assessment schemes and pertaining indices for reliability of hybrid energy sources in SIPS. The results show that due to the ability of the ENS index to measure the severity of the risky state, both types of indices are needed to satisfactorily observe the supply reliability, especially in hybrid-supplied SIPS. Index Terms-power system reliability; renewable energy sources; small isolated power systems; capacity reserve; system well-being analysis;

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Managing wind uncertainty and variability in the Irish power system

2009 IEEE Power & Energy Society General Meeting, 2009

This paper summarizes work that has been done to examine the impact of the uncertainty and variab... more This paper summarizes work that has been done to examine the impact of the uncertainty and variability of significant installed wind power on the Irish system. As more and more wind power is installed on the system, the operation of conventional plant on the system will be dramatically different. In this paper, three different aspects of the hour-to-hour operation of the Irish power system are examined. An innovative method to schedule the system is described, together with key results giving the effect of the uncertainty of wind on unit commitment of the system. The increased cycling of traditionally base-load units due to large amounts of wind power is quantified, and the steps to reduce this unwanted behavior are outlined. Finally, the use of intelligent decision tools based on sophisticated wind power forecasts for scheduling and provision of reserve is described.

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Decentralized secondary voltage control based on neural network and its effect on generator interaction

Proceedings of 8th Mediterranean Electrotechnical Conference on Industrial Applications in Power Systems, Computer Science and Telecommunications (MELECON 96), 1996

ABSTRACT

Intelligent coordinative voltage and reactive power control

International Journal of Electrical Power & Energy Systems, 2001

A novel local voltage control is proposed where each voltage controller of a generating unit is e... more A novel local voltage control is proposed where each voltage controller of a generating unit is equipped with additional coordinative voltage controller (CVC), which incorporates intelligent control into the power system. The controllers use artificial neural networks (ANN), trained on a large set of power system states. Optimal power flow (OPF) results serve as the optimal target in the ANN

ANN in local secondary voltage control concept

IJCNN'99. International Joint Conference on Neural Networks. Proceedings (Cat. No.99CH36339), 1999

ABSTRACT

An approach to secondary voltage control: a solution with local ANN controllers

MELECON '98. 9th Mediterranean Electrotechnical Conference. Proceedings (Cat. No.98CH36056), 1998

ABSTRACT

Cost-effective Primary Frequency Response at high Asynchronous Generation Levels

Restrained generation from wind and solar PV can provide a frequency response that is fast in com... more Restrained generation from wind and solar PV can provide a frequency response that is fast in comparison to conventional generation. However, the reduced inertia in a dispatch with little conventional generation can cause very fast initial drop in the frequency and it may be difficult to mitigate that with wind and solar PV alone. In the paper, we outline a method to compare frequency control strategies in such a system, present typical response characteristics of different options, and simulate some example cases for frequency co n ta in m e n t in th e I b er ia n p o w er sy s tem. T h e re su lts a r e demonstrative and additional analysis is required to draw more robust conclusions and to conclude on the costs and benefits of using wind and PV for frequency response.

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The flexible demand influence on the joint energy and reserve markets

2012 IEEE Power and Energy Society General Meeting, 2012

ABSTRACT Advances in control and information technology in electric grids of the future offer new... more ABSTRACT Advances in control and information technology in electric grids of the future offer new possibilities in the markets for the consumers. Using their flexible demand, not only can they influence the prices in the energy market but can also participate in the system reserve market. In the paper we present a new approach to the stochastic modeling of the demand-side reserve provision in co-optimized day-ahead electricity and reserve markets, where the consumers has the opportunity to participate as a reserve provider. The consumer participates in both markets for the cost reduction and the benefits obtained in them. The approach features a new method for the price determination of the demand-side reserve provision. The approach has been tested on IEEE RTS. The results illustrate the influence of demand flexibility on the ability of the consumers to provide reserve and on their subsequent benefits, including the reduced security cost.

Bid-based stochastic model for electricity prices: The impact of fundamental drivers on market dynamics

Energy Laboratory Publications MIT EL 00- …, 2000

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Energy Based System Well-Being Analysis

2007 IEEE Power Engineering Society General Meeting, 2007

Demand-side participation in system reserve provision in a stochastic market model with high wind penetration

2012 IEEE International Conference on Power System Technology (POWERCON), 2012

The generation capacity reserve forecasting in power system

2012 9th International Conference on the European Energy Market, 2012

Scheduling the Slovenian cascaded hydro system on the river Sava

IEEE Africon '11, 2011

Provision of operating states for power system simulation via Monte Carlo approach

The Advanced Bidding Strategy for Power Generators Based on Reinforcement Learning

Energy Sources, Part B: Economics, Planning, and Policy, 2014

The security of electricity supply: The economic downturn's influence in Slovenia

Energy Sources, Part B: Economics, Planning and Policy, 2014

Power system's security improvement through ANN-based decentralized secondary voltage control

Seminar on Neural Network Applications in Electrical Engineering, 2000

Demand-side system reserve provision in a stochastic market model

Energy Sources, Part B: Economics, Planning, and Policy, 2016

REserviceS D5.5. Ancillary services from wind and solar PV at transmission level - evaluation and conclusions of case studies

Indicative RES-E targets for the year 2010 and their fulfillment in slovenia

AFRICON 2007, 2007

Unified Approach to Reliability Assessment in an Isolated RES System

2006 International Conference on Probabilistic Methods Applied to Power Systems, 2006

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Managing wind uncertainty and variability in the Irish power system

2009 IEEE Power & Energy Society General Meeting, 2009

Download

Decentralized secondary voltage control based on neural network and its effect on generator interaction

Proceedings of 8th Mediterranean Electrotechnical Conference on Industrial Applications in Power Systems, Computer Science and Telecommunications (MELECON 96), 1996

ABSTRACT

Intelligent coordinative voltage and reactive power control

International Journal of Electrical Power & Energy Systems, 2001

ANN in local secondary voltage control concept

IJCNN'99. International Joint Conference on Neural Networks. Proceedings (Cat. No.99CH36339), 1999

ABSTRACT

An approach to secondary voltage control: a solution with local ANN controllers

MELECON '98. 9th Mediterranean Electrotechnical Conference. Proceedings (Cat. No.98CH36056), 1998

ABSTRACT

Cost-effective Primary Frequency Response at high Asynchronous Generation Levels

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The flexible demand influence on the joint energy and reserve markets

2012 IEEE Power and Energy Society General Meeting, 2012

A. Gubina

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