Hybrid renewable energy systems (HRES) should be designed appropriately with an adequate combination of different renewable sources and various energy storage methods to overcome the problem of intermittency of renewable energy resources. A multi-criteria approach is proposed in this study to design an HRES including wind turbine, photovoltaic panels, fuel cell, electrolyser, hydrogen tank, and battery storage unit with an intermittent load. Three design criteria including loss of power supply probability, total energy loss (TEL), and the power difference between generation and storing capacity (as TELSUB) are taken into account in minimising the total cost of the system considering the interest rate and lifetime. The justifications and advantages of using these criteria are thoroughly discussed along with appropriate presentation of the results. The purpose of considering TEL and TELSUB is discussed thoroughly. The ɛ-constraint method is used to handle practical constraints of the proposed multi-criteria problem to construct a multi-objective fitness function. Shuffled frog leaping algorithm is implemented to achieve better optimal results. The proposed approach is implemented using real wind speed and solar irradiance data for a specific location with an intermittent load demand. The results verify performance of the proposed multicriteria design procedure.
With the rise of distributed energy resources and the increasing activation of flexibility resources by Distribution Systems Operators (DSOs), the Transmission System Operators (TSOs) need to co-ordinate their actions with those of the DSOs. This research uses a look-ahead multi-interval (LA-MI) framework for analyzing this coordination and explores two formulations. Firstly in the exogenous DSO model, a mixedinteger linear program is developed to reflect the pragmatic approach in many real situations whereby the TSO can only anticipate statistically the actions of the DSO. In the embedded DSO model, as a comparator, we propose a new organizational setup for the TSO-DSO operational coordination mechanism. In the resulting bilevel decomposition, a new method to calculate Benders cuts is developed and tested on a modified IEEE 118-bus test system as a transmission network and two modified IEEE 33bus test systems as distribution networks. The benefits of the LA-MI coordination framework are substantial in comparison with the current Look-Ahead Single-Interval (LA-SI) coordination framework widely used in Europe.transmission system at time t (M W/M V ar). P T S bct /Q T S bct Active/Reactive power flow from bus b to bus c in transmission system at time t (M W/M V ar). P DS ijbt /Q DS ijbt Active/Reactive power flow from bus i to bus j of a distribution system which is connected to bus b of a transmission system at time t (M W/M V ar). P DS g pt /Q DS g pt Active/reactive consumption for the embedded DSO model at point of common coupling at time t (M W/M V ar). (θ/v s ) (b/i)t Phase angle/Square of voltage magnitude at bus b/i in transmission/distribution systems at time t. β U P bt /β DW bt Binary variables that represent the state of up/down operating reserve activation at bus b and time t for the exogenous DSO activation model. It also represents the concept of implication in the inference dual theorem in the embedded DSO activation model. α U P ubt /α DW dbt Binary variables that represent the state of up/down EERs activation at bus (u/d) ∈ {N ub /N db } of distribution systems which is located at bus b of a transmission system at time t for the exogenous DSO activation model. It also represents the concept of implication in the inference dual theorem in the embedded DSO activation model. λ/Π/µ/δ Dual variables of equality constraints (1b)-(1e). D/Y Dual variables of complementary slackness conditions/Logical indicators. Γ Boundary for the determined Benders cuts in the LBBD model. g Binary variables that reflect combination of complicating variable. Ĝ Boolean variables for different combinations of complicating variables in LBBD. Abbreviations T SO/DSO Transmission/Distribution system operator. T S/DS Superscript for transmission/distribution system. DR/EER Demand response/Embedded energy resource. GDP Generalized disjunctive programming. LA − M I Look-ahead multi-interval.
The flexibility services available from embedded resources, being attractive to both the network operators and retailers, pose a problem of co-ordination and market design at the local level. This research considers how a Flexibility Market Operator (FMO) at the local level, analogous to market operators at the wholesale level, can improve the real-time operation of the power systems and efficiently manage the interests of the TSO, DSO, and Retailers. Using generalized disjunctive programming, a stochastic bilevel representation of the task is reformulated as a stochastic mixed-logical linear program (MLLP) with indicator constraints. An Inference-Dual-Based Decomposition (IDBD) Algorithm is developed with sub-problem relaxation to reduce the iterations. Using expected Shapley values, a new payoff mechanism is introduced to allocate the cost of service activations in a fair way. Finally, the performance and benefits of the proposed method are assessed via a case study application.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.