A discussion on electricity prices, or the two sides of the coin

We examine how different pricing frameworks deal with non-convex features typical of day-ahead energy prices when the power system is hydro-dominated, like in Brazil. For the system operator, requirements of minimum generation translate into feasibility issues that are fundamental to carry the generated power through the network. When utilities are remunerated at a price depending on Lagrange multipliers computed for a system with fixed commitment, the corresponding values sometimes fail to capture a signal that recovers costs. Keeping in mind recent discussions for the Brazilian power system, we analyse mechanisms that provide a compromise between the needs of the generators and those of the system operator. After characterizing when a price supports a generation plan, we explain in simple terms dual prices and related concepts, such as minimal uplifts and bi-dual problems. We present a new pricing mechanism that guarantees cost recovery to all agents, without over-compensations. Instead of using Lagrange multipliers, the price is defined as the solution to an optimization problem. The behaviour of the new rule is compared to two other proposals in the literature on illustrative examples, including a small, yet representative, hydro-thermal system. This article is part of the theme issue ‘The mathematics of energy systems’.

Download Full-text

Preventing Large-Scale Emergencies in Modern Power Systems: AI Approach

Journal of Advanced Computational Intelligence and Intelligent Informatics ◽

10.20965/jaciii.2014.p0714 ◽

2014 ◽

Vol 18 (5) ◽

pp. 714-727 ◽

Cited By ~ 2

Author(s):

Michael Negnevitsky ◽

◽

Nikita V. Tomin ◽

Christian Rehtanz ◽

◽

...

Keyword(s):

Power Systems ◽

Power System ◽

Intelligent Systems ◽

Large Scale ◽

Energy Systems ◽

Critical Conditions ◽

Major Power ◽

System Operator ◽

Major Emergencies ◽

The University

In recent years, due to liberalization, power systems are being operated closer and closer to their limits. At the same time, they have increased in size and complexity. Both factors increase the risk of major power outages and blackouts. In emergency and abnormal conditions, a power system operator has to deal with large amounts of data. However, due to emotional and psychological stress, an operatormay not be able to respond to critical conditions adequately and make correct decisions promptly. Mistakes can damage very expensive power system equipment or worse lead to major emergencies and catastrophic situations. Intelligent systems can play an important role by alarming the operator and suggesting the necessary actions to be taken to deal with a given emergency. This paper outlines some experience obtained at the University of Tasmania, Australia, Energy Systems Institute, Russia and TU-Dortmund University, Germany in developing intelligent systems for preventing large-scale emergencies and blackouts in modern power systems.

Download Full-text

Bridging granularity gaps to decarbonize large‐scale energy systems—The case of power system planning

Energy Science & Engineering ◽

10.1002/ese3.891 ◽

2021 ◽

Author(s):

Karl‐Kiên Cao ◽

Jannik Haas ◽

Evelyn Sperber ◽

Shima Sasanpour ◽

Seyedfarzad Sarfarazi ◽

...

Keyword(s):

Power System ◽

Large Scale ◽

Energy Systems ◽

Power System Planning ◽

System Planning

Download Full-text

Co-Simulation Framework for Optimal Allocation and Power Management of DGs in Power Distribution Networks Based on Computational Intelligence Techniques

Electronics ◽

10.3390/electronics10141648 ◽

2021 ◽

Vol 10 (14) ◽

pp. 1648

Author(s):

Marinko Barukčić ◽

Toni Varga ◽

Vedrana Jerković Jerković Štil ◽

Tin Benšić

Keyword(s):

Power System ◽

Power Management ◽

Computational Intelligence ◽

Input Data ◽

Optimization Problem ◽

Optimal Allocation ◽

Distribution Networks ◽

Distributed Generations ◽

Data Resolution ◽

The Impact

The paper researches the impact of the input data resolution on the solution of optimal allocation and power management of controllable and non-controllable renewable energy sources distributed generation in the distribution power system. Computational intelligence techniques and co-simulation approach are used, aiming at more realistic system modeling and solving the complex optimization problem. The optimization problem considers the optimal allocation of all distributed generations and the optimal power control of controllable distributed generations. The co-simulation setup employs a tool for power system analysis and a metaheuristic optimizer to solve the optimization problem. Three different resolutions of input data (generation and load profiles) are used: hourly, daily, and monthly averages over one year. An artificial neural network is used to estimate the optimal output of controllable distributed generations and thus significantly decrease the dimensionality of the optimization problem. The proposed procedure is applied on a 13 node test feeder proposed by the Institute of Electrical and Electronics Engineers. The obtained results show a huge impact of the input data resolution on the optimal allocation of distributed generations. Applying the proposed approach, the energy losses are decreased by over 50–70% by the optimal allocation and control of distributed generations depending on the tested network.

Download Full-text

Position Tolerance Verification Using Simulated Gaging

15th Design Automation Conference: Volume 1 — Computer-Aided and Computational Design ◽

10.1115/detc1989-0036 ◽

1989 ◽

Author(s):

F. Etesami

Keyword(s):

Lagrange Multipliers ◽

Optimization Problem ◽

Coordinate Measuring Machines ◽

Vision Systems ◽

Dimensional Inspection ◽

Perfect Form ◽

Nominal Feature ◽

Manual Tasks ◽

Tolerance Verification

Abstract One of the routine manual tasks in dimensional inspection is the assembly verification of circular features by mechanical gaging. With the aid of coordinate measuring machines or vision systems, this task can be performed more efficiently through simulation or soft-gaging. A formulation is presented for interpretation of 2D position tolerance specifications. Simulated gages are constructed from datum features as a set of constraint relationships. The measure of perfect-form position-imperfection is determined as the distance between the measured and the nominal feature positions subject to datum constraint requirements. The derived formulation is applied to an example part with a hole-slot datum-priority-frame. This formulation results in a three-variable optimization problem which is solved by an Augmented Lagrange Multipliers technique. The extension of the formulation to 3D is also discussed, but without reference to a specific representation.

Download Full-text

Frequency and inertia response effects, capabilities, and possibilities in renewable energy sources

Recent Advances in Computer Science and Communications ◽

10.2174/2666255814666210121155533 ◽

2021 ◽

Vol 14 ◽

Author(s):

Jishu Mary Gomez ◽

Prabhakar Karthikeyan Shanmugam

Keyword(s):

Renewable Energy ◽

Power System ◽

Frequency Control ◽

Renewable Energy Sources ◽

Energy Systems ◽

Load Shedding ◽

System Stability ◽

Frequency Regulation ◽

Control Schemes ◽

Inertia Response

Background & Objectives: The global power system is in a state of continuous evolution, incorporating more and more renewable energy systems. The converter-based systems are void of inherent inertia control behavior and are unable to curb minor frequency deviations. The traditional power system, on the other hand, is made up majorly of synchronous generators that have their inertia and governor response for frequency control. For improved inertial and primary frequency response, the existing frequency control methods need to be modified and an additional power reserve is to be maintained mandatorily for this purpose. Energy self-sufficient renewable distributed generator systems can be made possible through optimum active power control techniques. Also, when major global blackouts were analyzed for causes, solutions, and precautions, load shedding techniques were found to be a useful tool to prevent frequency collapse due to power imbalances. The pre-existing load shedding techniques were designed for traditional power systems and were tuned to eliminate low inertia generators as the first step to system stability restoration. To incorporate emerging energy possibilities, the changes in the mixed power system must be addressed and new frequency control capabilities of these systems must be researched. Discussion: In this paper, the power reserve control schemes that enable frequency regulation in the widely incorporated solar photovoltaic and wind turbine generating systems are discussed. Techniques for Under Frequency Load Shedding (UFLS) that can be effectively implemented in renewable energy enabled micro-grid environment for frequency regulation are also briefly discussed. The paper intends to study frequency control schemes and technologies that promote the development of self- sustaining micro-grids. Conclusion: The area of renewable energy research is fast emerging with immense scope for future developments. The comprehensive literature study confirms the possibilities of frequency and inertia response enhancement through optimum energy conservation and control of distributed energy systems.

Download Full-text

Cyber-Physical Energy Systems Approach for Engineering Power System State Estimation in Smart Grids

Soft Computing Applications - Advances in Intelligent Systems and Computing ◽

10.1007/978-3-319-62521-8_11 ◽

2017 ◽

pp. 118-132

Author(s):

Seshadhri Srinivasan ◽

Øystein Hov Holhjem ◽

Giancarlo Marafioti ◽

Geir Mathisen ◽

Alessio Maffei ◽

...

Keyword(s):

Power System ◽

State Estimation ◽

Smart Grids ◽

Systems Approach ◽

Energy Systems ◽

System State ◽

Power System State Estimation ◽

Physical Energy

Download Full-text

A Hybrid PV-Battery/Supercapacitor System and a Basic Active Power Control Proposal in MATLAB/Simulink

Electronics ◽

10.3390/electronics9010129 ◽

2020 ◽

Vol 9 (1) ◽

pp. 129 ◽

Cited By ~ 4

Author(s):

Mustafa Ergin Şahin ◽

Frede Blaabjerg

Keyword(s):

Renewable Energy ◽

Power Control ◽

Hybrid System ◽

Storage System ◽

Energy Systems ◽

Energy Generation ◽

Active Power ◽

Active Power Control ◽

Matlab Simulink ◽

Two Sides

An increase in the integration of renewable energy generation worldwide brings along some challenges to energy systems. Energy systems need to be regulated following grid codes for the grid stability and efficiency of renewable energy utilization. The main problems that are on the active side can be caused by excessive power generation or unregulated energy generation, such as a partially cloudy day. The main problems on the load side can be caused by excessive or unregulated energy demand or nonlinear loads which deteriorate the power quality of the energy networks. This study focuses on the energy generation side as active power control. In this study, the benefits of supercapacitor use in a hybrid storage system are investigated and analyzed. A hybrid system in which photovoltaic powered and stored the energy in battery and supercapacitor are proposed in this study to solving the main problems in two sides. The supercapacitor model, photovoltaic model, and the proposed hybrid system are designed in MATLAB/Simulink for 6 kW rated power. Also, a new topology is proposed to increase the energy storage with supercapacitors for a passive storage system. The instantaneous peak currents energy is aimed to store in supercapacitors temporarily with this topology. The main advantages of this topology are voltage stabilization in two sides by the supercapacitors and a limitation of the battery load, which directly results in longer battery life and decreases the system cost. The simulation results are investigated for this topology.

Download Full-text

Towards 100% renewable energy systems: Uncapping power system flexibility

Energy Policy ◽

10.1016/j.enpol.2016.01.025 ◽

2016 ◽

Vol 92 ◽

pp. 69-82 ◽

Cited By ~ 85

Author(s):

G. Papaefthymiou ◽

Ken Dragoon

Keyword(s):

Renewable Energy ◽

Power System ◽

Energy Systems ◽

Renewable Energy Systems ◽

Power System Flexibility

Download Full-text

PSS with SVC Damping Controllers Coordinated Design and Real-Time Implementation in Multi-Machine Power System Using Advanced Adaptive PSO

International Journal of Emerging Electric Power Systems ◽

10.1515/ijeeps-2013-0049 ◽

2013 ◽

Vol 14 (5) ◽

pp. 487-498

Author(s):

Rajendraprasad Narne ◽

P.C. Panda

Keyword(s):

Power System ◽

Real Time ◽

Optimization Problem ◽

Test System ◽

Swarm Optimization ◽

Damping Controllers ◽

Control Schemes ◽

Controller Performance ◽

Adaptive Pso ◽

System Stabilizer

Abstract This article proposed coordinated tuning and real-time implementation of power system stabilizer (PSS) with static var compensator (SVC) in multi-machine power system. The design of proposed coordinated damping controller is formulated as an optimization problem, and the controller gains are optimized instantaneously using advanced adaptive particle swarm optimization. Here, PSS with SVC installed in multi-machine system is examined. The coordinated tuning among the damping controllers is performed on the non-linear power system dynamic model. Finally, the proposed coordinated controller performance is discussed with time-domain simulations. Different loading conditions are employed on the test system to test the robustness of proposed coordinate controller, and the simulation results are compared with four different control schemes. To validate the proposed controller, the test power system is also implemented on real-time (OPAL-RT) simulator, and acceptable results are reported for its verifications.

Download Full-text