Electric vehicles participation in load frequency control of an interconnected power system is not sustainable

Research output: Conference Papers (RGC: 31A, 31B, 32, 33)Abstractpeer-review

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Detail(s)

Original languageEnglish
Publication statusPublished - Dec 2021

Conference

Title6th AIEE Energy Symposium Current and Future Challenges to Energy Security
LocationOnline
PlaceItaly
CityMilan
Period14 - 17 December 2021

Abstract

Overview
Interconnected power systems (IPSs) are prevalent in modern-day high voltage power networks where two or more power system areas agree on power-sharing between them through tie-lines. In such IPSs, two operation modes are possible; 1). regular operation mode where each area should have the capacity to meet its electricity demands plus the scheduled interchange between the neighbouring areas as per the power-sharing agreement from its power generation systems; 2). emergency operation mode where a sudden loss of power generation would arise, creating imbalances and ultimately leading to frequency deviations. In emergency operation mode, the system operators in respective areas should regulate the load and generation to bring back the frequency to an equilibrium value. The process of bringing back the frequency to a nominal value is known as load frequency control (LFC). At this point, the required energy demands can immediately be drawn from all the neighbouring areas' reserve capacity to meet the power-sharing agreement. The reserve capacity is something that can be planned by adopting various systems; in literature, many have proposed options like EVs, renewables, and storage systems. Among these, EVs use as an auxiliary power source to mitigate the LFC seems more popular. There are already many studies showings how EVs participation is solving LFC better compared to its counterparts. However, most of these studies were limited to participation protocols, standards, performance. Well, EVs might address the LFC and enable the interconnected system's reliable and stable operation, but is it happening sustainably is a question? This has motivated us to investigate whether the EVs use in IPS for LFC is a sustainable option or not by viewing the EVs and the electric power system from a life cycle perspective.

System Design, Methods and Data Collection
The designed IPS is a two-area power system. It consists of fossil fuel-based thermal generators, solar power generators and EVs. Between the two areas, a high voltage direct current (HVDC) tie-line exists. The total load in area-1 is 800 MW and has three generators with a cumulative generation capacity of 1400 MW. Whereas in area-2, the total load is 2200 MW, and the generation is 1420 MW from two generators.
A mixed-method approach called RePLiCA that combines Resilience Performance and Life Cycle Analysis is applied (Kumar, 2021). Resilience performance is estimated based on a supply and demand variation followed by EV participation. For this, we applied four disruptive scenarios (5%, 10%, 15%, and 20%) to see the variation in frequency and power imbalances with 20% as the maximum allowable shock considering limitations with the physical infrastructure. A meta-heuristic optimization technique, i.e., particle swarm optimization (PSO) based on swarm intelligence, is chosen to set the LFC controller parameters. The life cycle analysis is conducted using the ReCiPe 2016 Midpoint (H) V1.02 method in SimaPro 8.2.20 to estimate the carbon dioxide (CO2) emissions possible from the participated EVs in LFC by taking 1 kWh of energy stored as a functional unit.

Results and Conclusions
The applied RePLiCA approach gave clear insights on EVs participation in IPS. The results include the power deviation (MW), load change (MWh), change in frequency (Hz), response time or settling time (sec), and carbon dioxide emissions (kgCO2 eq.). The observed power deviation and load change under four disruptive scenarios are varied between 40 to 160 MW and 62.75 to 251 MWh, respectively. The change in frequency in area-1 is 0.36 to 0.83 Hz and in area-2 is 0.28 0.72 Hz. The recovery time was observed to vary between 18.60 to 46.43 sec, which is acceptable under the secondary control. While analysing the environmental sustainability results, Ontario state in Canada energy mix is considered. According to the sustainability results, the participated EVs in the LFC of IPS under the four disruptive scenarios could emit approximately 4769 to 19076 kgCO2 eq.
Overall, the results of this study suggest that the EVs participation role in LFC is promising in enabling the interconnected system's reliable and stable operation, but it is not sustainable. At the same time, we also investigated the possibility of reducing the emissions released. However, we understood that this is only possible if EVs are charged with renewable sources or the national energy mix is free from fossil fuel energy.

Research Area(s)

  • interconnected power systems, load frequency control, Electric vehicle aggregator, Electric vehicle participation, EV as auxiliary power source, Particle swarm optimisation, frequency resilience, EV life cycle assessment, EV battery LCA

Bibliographic Note

Information for this record is supplemented by the author(s) concerned.

Citation Format(s)

Electric vehicles participation in load frequency control of an interconnected power system is not sustainable. / Nallapaneni, Manoj Kumar; Chopra, Shauhrat S.

2021. Abstract from 6th AIEE Energy Symposium Current and Future Challenges to Energy Security, Milan, Italy.

Research output: Conference Papers (RGC: 31A, 31B, 32, 33)Abstractpeer-review