scholarly journals Risk Analysis of the Power System Protection Delayed Triggers in Power Network Integrating Renewable Energy Sources in Fault Dynamic States

2020 ◽  
Author(s):  
Mateusz Szablicki ◽  
Piotr Rzepka ◽  
Adrian Halinka
Keyword(s):  
Power Systems ◽  
Power System ◽  
Renewable Energy Sources ◽  
Operation Time ◽  
Power Network ◽  
Renewable Generation ◽  
System Protection ◽  
Energy Needs ◽  
Digital Protection ◽  
Decision Algorithms

In the development of power systems it is indicated very often, that transformation of power systems should be carried out in accordance with the idea of energy democracy. This will develop energy communities, that are trying to meet energy needs by using local renewable generation sources. This may result with a temporary low load on the MV lines connecting the community grid and the power system. Such state may cause incorrect operation of power protection systems. This can cause an extended protection operation time, due to decision algorithms inactivity at low values of measurement currents. Therefore, the detailed MV lines overcurrent digital protection model and a dynamic model of the power network were developed. The simulation results are showing that the settings of the parameters activating the protection decision algorithms affect their operation time in dynamic conditions. The conclusion is that the development of the power protection automatics must be carried out in the same time (preferably in advance) with the change of the power system operation model. This is very important for future power systems with high penetration energy communities and renewable generation sources.

scholarly journals Simulation Verification of Overcurrent Protection Operation in Power Networks Integrating Renewable Energy Sources in Energy Communities

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2193
Author(s):  
Mateusz Szablicki ◽  
Piotr Rzepka ◽  
Adrian Halinka
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Renewable Energy Sources ◽  
Design Stage ◽  
Energy Sources ◽  
Power System Protection ◽  
System Protection ◽  
Energy Community ◽  
Digital Protection

This publication discusses the risks of further use of classical overcurrent protections in modern power systems. The increasing penetration of renewable energy sources has caused a lot of challenges, among other things, the development of energy communities that balance local generation and consumption. Usually the interconnection line between the energy community and power systems are only used to balance the shortage or overflow of energy. As a result, most of the time these connections can be low loaded. Such a state can cause incorrect operation of power system protection approached, because the current level values are smaller than the required activation level for the protections. This article presents the potential incorrect operation of digital power system protection with overcurrent function. The obtained simulation results clearly show that the correctness of protection operation is strongly dependent on the level load of lines and the parameters and structure of the protection decision algorithms. These problems occur during low load line periods because these were not taken into account during the classical digital protection design stage. In the future this can cause problems with the fulfillment of the basic protection requirements of stability, speed, sensitivity. This publication suggests extra problems for power system protection research.

scholarly journals Optimal Coordination of Aggregated Hydro-Storage with Residential Demand Response in Highly Renewable Generation Power System: The Case Study of Finland

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1037 ◽  
Author(s):  
Arslan Bashir ◽  
Matti Lehtonen
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Demand Response ◽  
Renewable Energy Sources ◽  
Renewable Generation ◽  
Generation Structure ◽  
Optimal Coordination ◽  
Residential Demand ◽  
Generation Power

Current energy policy-driven targets have led to increasing deployment of renewable energy sources in electrical grids. However, due to the limited flexibility of current power systems, the rapidly growing number of installations of renewable energy systems has resulted in rising levels of generation curtailments. This paper probes the benefits of simultaneously coordinating aggregated hydro-reservoir storage with residential demand response (DR) for mitigating both load and generation curtailments in highly renewable generation power systems. DR services are provided by electric water heaters, thermal storages, electric vehicles, and heating, ventilation and air-conditioning (HVAC) loads. Accordingly, an optimization model is presented to minimize the mismatch between demand and supply in the Finnish power system. The model considers proportions of base-load generation comprising nuclear, and combined heat and power (CHP) plants (both CHP-city and CHP-industry), as well as future penetration scenarios of solar and wind power that are constructed, reflecting the present generation structure in Finland. The findings show that DR coordinated with hydropower is an efficient curtailment mitigation tool given the uncertainty in renewable generation. A comprehensive sensitivity analysis is also carried out to depict how higher penetration can reduce carbon emissions from electricity co-generation in the near future.

scholarly journals Managing Distributed Flexibility under Uncertainty by Combining Deep Learning with Duality

2021 ◽  
Author(s):  
Georgios Tsaousoglou ◽  
Katerina Mitropoulou ◽  
Konstantinos Steriotis ◽  
Nikolaos Paterakis ◽  
Pierre Pinson ◽  
...  
Keyword(s):  
Deep Learning ◽  
Power Systems ◽  
Renewable Energy Sources ◽  
Economic Dispatch ◽  
Multiple Sources ◽  
Arrival Times ◽  
Energy Needs ◽  
Markov Decision ◽  
Dual Variables ◽  
Economic Dispatch Problem

<div>In modern power systems, small distributed energy resources (DERs) are considered a valuable source of flexibility towards accommodating high penetration of Renewable Energy Sources (RES). In this paper we consider an economic dispatch problem for a community of DERs, where energy management decisions are made online and under uncertainty. We model multiple sources of uncertainty such as RES, wholesale electricity prices as well as the arrival times and energy needs of a set of Electric Vehicles. The economic dispatch problem is formulated as a multi-agent Markov Decision Process. The difficulties lie in the curse of dimensionality and in guaranteeing the satisfaction of constraints under uncertainty.</div><div>A novel method, that combines duality theory and deep learning, is proposed to tackle these challenges. In particular, a Neural Network (NN) is trained to return the optimal dual variables of the economic dispatch problem. By training the NN on the dual problem instead of the primal, the number of output neurons is dramatically reduced, which enhances the performance and reliability of the NN. Finally, by treating the resulting dual variables as prices, each distributed agent can self-schedule, which guarantees the satisfaction of its constraints. As a result, our simulations show that the proposed scheme performs reliably and efficiently.</div>

scholarly journals A Review of Virtual Inertia Techniques for Renewable Energy-Based Generators

2020 ◽  
Author(s):  
Ana Fernández-Guillamón ◽  
Emilio Gómez-Lázaro ◽  
Eduard Muljadi ◽  
Ángel Molina-Garcia
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Power Plants ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Extensive Discussion ◽  
Renewable Sources ◽  
Virtual Inertia ◽  
Alternative Sources

Over recent decades, the penetration of renewable energy sources (RES), especially photovoltaic and wind power plants, has been promoted in most countries. However, as these both alternative sources have power electronics at the grid interface (inverters), they are electrically decoupled from the grid. Subsequently, stability and reliability of power systems are compromised. Inertia in power systems has been traditionally determined by considering all the rotating masses directly connected to the grid. Thus, as the penetration of renewable units increases, the inertia of the power system decreases due to the reduction of directly connected rotating machines. As a consequence, power systems require a new set of strategies to include these renewable sources. In fact, ‘hidden inertia,’ ‘synthetic inertia’ and ‘virtual inertia’ are terms currently used to represent an artificial inertia created by inverter control strategies of such renewable sources. This chapter reviews the inertia concept and proposes a method to estimate the rotational inertia in different parts of the world. In addition, an extensive discussion on wind and photovoltaic power plants and their contribution to inertia and power system stability is presented.

scholarly journals Converter-driven Stability Analysis of Power Systems Integrated with Hybrid Renewable Energy Sources

2021 ◽  
Author(s):  
Jianqiang Luo ◽  
Yiqing Zou ◽  
Siqi Bu
Keyword(s):  
Renewable Energy ◽  
Stability Analysis ◽  
Power Systems ◽  
Power System ◽  
Dynamic Models ◽  
Renewable Energy Sources ◽  
Energy Sources ◽  
Power Electronic ◽  
Modal Interaction ◽  
Hybrid Renewable Energy

Various renewable energy sources such as wind power and photovoltaic (PV) have been increasingly integrated into the power system through power electronic converters in recent years. However, power electronic converter-driven stability issues under specific circumstances, for instance, modal resonances might deteriorate the dynamic performance of the power systems or even threaten the overall stability. In this paper, the integration impact of a hybrid renewable energy source (HRES) system on modal interaction and converter-driven stability is investigated in an IEEE 16-machine 68-bus power system. Firstly, an HRES system is introduced, which consists of full converter-based wind power generation (FCWG) and full converter-based photovoltaic generation (FCPV). The equivalent dynamic models of FCWG and FCPV are then established, followed by the linearized state-space modeling. On this basis, converter-driven stability analyses are performed to reveal the modal resonance mechanisms of the interconnected power systems and the modal interaction phenomenon. Additionally, time-domain simulations are conducted to verify effectiveness of dynamic models and support the converter-driven stability analysis results. To avoid detrimental modal resonances, an optimization strategy is further proposed by retuning the controller parameters of the HRES system. The overall results demonstrate the modal interaction effect between external AC power system and the HRES system and its various impacts on converter-driven stability.

Parametric Modeling and Optimal Control of a Combined Heating and Power System With Energy Storage

2020 ◽  
Author(s):  
Claudia Lucia De Pascalis ◽  
Stephanie Stockar
Keyword(s):  
Energy Storage ◽  
Power Systems ◽  
Power System ◽  
Energy Management ◽  
Renewable Energy Sources ◽  
Cost Effective ◽  
Parametric Modeling ◽  
Medium Size ◽  
Energy Management Strategy ◽  
Generation Cost

Abstract Cogeneration is a well-known and cost effective solution for generating power and heat within the same plant, leading to improved overall efficiency and reduced generation cost. Combined heating and power systems can facilitate the penetration of renewable energy sources in medium size applications through the integration of electric and thermal energy storage units. Due to the complexity of the plant as well as significantly variability in power demand and generation, the design and operation of such systems requires a systematic co-optimization of plant and controller for guaranteeing near optimal performance. In this scenario, this paper presents a physics-based parametric modeling approach for the characterization of the main components of a 1MW combined heating and power system that includes renewable sources, electric and thermal storage devices. To demonstrate the model flexibility and potential benefits achieved by an optimal sizing, the system energy management is optimized using Dynamic Programming. The operational costs for different configurations are compared showing that an optimization of the energy management strategy in conjunction with an improved system sizing lead to more than 6% of reduction in the operational cost.

scholarly journals Operational Planning and Bidding for District Heating Systems with Uncertain Renewable Energy Production

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3310 ◽  
Author(s):  
Ignacio Blanco ◽  
Daniela Guericke ◽  
Anders Andersen ◽  
Henrik Madsen
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Electricity Markets ◽  
Electricity Market ◽  
Renewable Energy Sources ◽  
District Heating ◽  
Operational Planning ◽  
Solution Approach ◽  
The Impact

In countries with an extended use of district heating (DH), the integrated operation of DH and power systems can increase the flexibility of the power system, achieving a higher integration of renewable energy sources (RES). DH operators can not only provide flexibility to the power system by acting on the electricity market, but also profit from the situation to lower the overall system cost. However, the operational planning and bidding includes several uncertain components at the time of planning: electricity prices as well as heat and power production from RES. In this publication, we propose a planning method based on stochastic programming that supports DH operators by scheduling the production and creating bids for the day-ahead and balancing electricity markets. We apply our solution approach to a real case study in Denmark and perform an extensive analysis of the production and trading behavior of the DH system. The analysis provides insights on system costs, how DH system can provide regulating power, and the impact of RES on the planning.

scholarly journals Optimal Sizing and Spatial Allocation of Storage Units in a High-Resolution Power System Model

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3365 ◽  
Author(s):  
Lukas Wienholt ◽  
Ulf Müller ◽  
Julian Bartels
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Power Transmission ◽  
Renewable Generation ◽  
Large Power ◽  
Transmission Grid ◽  
Storage Units

The paradigm shift of large power systems to renewable and decentralized generation raises the question of future transmission and flexibility requirements. In this work, the German power system is brought to focus through a power transmission grid model in a high spatial resolution considering the high voltage (110 kV) level. The fundamental questions of location, type, and size of future storage units are addressed through a linear optimal power flow using today’s power grid capacities and a generation portfolio allowing a 66% generation share of renewable energy. The results of the optimization indicate that for reaching a renewable energy generation share of 53% with this set-up, a few central storage units with a relatively low overall additional storage capacity of around 1.6 GW are required. By adding a constraint of achieving a renewable generation share of at least 66%, storage capacities increase to almost eight times the original capacity. A comparison with the German grid development plan, which provided the basis for the power generation data, showed that despite the non-consideration of transmission grid extension, moderate additional storage capacities lead to a feasible power system. However, the achievement of a comparable renewable generation share provokes a significant investment in additional storage capacities.

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