Service-based Reliability Analysis of Integrated Electricity-heat Systems Considering Thermal Dynamics

The essential task of integrated electricity-heat systems(IEHSs)is to provide customers with reliable electric and heating services.From the perspective of customers,it is reasonable to analyze the reliabilities of IEHSs based on the ability to provide energy services with a reasonable assurance of continuity and quality,which are termed as service-based reliabilities.Due to the thermal inertia existing in IEHSs,the heating service performances can present slow dynamic characteristics,which has a great impact on the service satisfaction of customers.The neglect of such thermal dynamics will bring about inaccurate service-based reliability measurement,which can lead to the inefficient dispatch decisions of system operators.Therefore,it is necessary to provide a tool which can analyze the servicebased reliabilities of IEHSs considering the impacts of thermal dynamics.This paper firstly models the energy service performance of IEHSs in contingency states.Specifically,the nodal energy supplies are obtained from the optimal power and heat flow model under both variable hydraulic and thermal conditions,in which the transmission-side thermal dynamics are formulated.On this basis,the energy service performances for customers are further determined with the formulation of demandside thermal dynamics.Moreover,a service-based reliability analysis framework for the IEHSs is proposed utilizing the timesequential Monte Carlo simulation(TSMCS)technique with the embedded decomposition algorithm.Furthermore,the indices for quantifying service-based reliabilities are defined based on the traditional reliability indices,where dynamic service performances and service satisfactions of customers are both considered.Numerical simulations are carried out with a test system to validate the effectiveness of the proposed framework.

Economical evaluation of large-scale photovoltaic systems using Universal Generating Function techniques

Solar energy plays an important role in the global energy framework for future.Comparing with conventional generation systems using fossil fuels,the cost structure of photovoltaic(PV)systems is different:the capital cost is higher while the operation cost is negligible.Reliabilities of the PV system can also influence the cost for producing electricity.Investors,planners and regulators require deep insight into the return and cost of a PV project.A reliability based economical assessment of largescale PV systems has been conducted utilizing Universal Generating Function(UGF)techniques.The reliability models of solar panel arrays,PV inverters and energy production units(EPUs)are represented as the corresponding UGFs.The expected energy production models for different PV system configurations have also been developed.The expected unit cost of electricity has been calculated to provide informative metrics for making optimal decisions.The proposed method has been applied to determine the PV system configuration which provides electricity for a water purification process.