Probabilistic Energy Flow Calculation through the Nataf Transformation and Point Estimation

Qin Qin,Fang Fang,Li Li,Ma Ma

doi:10.3390/app9163291

Abstract

With the increasing capacity of renewable energy sources, uncertainties regarding renewable energy and other dynamic loads in integrated energy systems (IESs) are increasing. Thus, it is necessary to study the probabilistic energy flow (PEF) of IESs. However, existing PEF calculation methods such as the point estimate method (PEM) are computationally inefficient when there are many random variables and estimated points; moreover, relatively large errors can occur when the estimated points are outside their limits. Hence, this paper presents a calculation method that addresses these problems. Because there are correlations among the variables, the Nataf transformation is employed to control the correlation quickly and effectively. A model for an IES that is interconnected with natural gas and electricity systems and accounts for the uncertainties of wind plants, photovoltaic power plants, and dynamic gas loads is presented. Correlations between wind plants and photovoltaic power plants are handled using the Nataf transformation. Finally, a modified PEM is developed to solve the PEF. For situations in which the estimated points exceed their boundaries, the power transformation and equal constraint transformation methods are used. The results of time-domain simulations demonstrate the effectiveness of the proposed approach.

Highlights

The increasing demand for energy has resulted in increased concerns regarding energy sources, and the exploration of new energy supply modes has attracted considerable interest
For 5-point estimate method (PEM) and 7-PEM based on Zhao and Ono’s multipoint estimation method (MPEM), direct calculations will lead to an exponential growth in the computation cost; we developed a modified MPEM
A PEM based on the Nataf transformation for computing probabilistic energy flow (PEF) in an integrated energy systems (IESs) was proposed in this paper

Summary

Introduction

The increasing demand for energy has resulted in increased concerns regarding energy sources, and the exploration of new energy supply modes has attracted considerable interest. The concept of integrated energy systems (IESs) challenges that of traditional energy systems. Compared with traditional energy systems, these systems have significant advantages [2,3]. All types of energy are closely coupled, which makes them complementary and mutually beneficial, and they can realize cascade utilization and collaborative optimization of energy. Research on IESs is mostly focused on three aspects: energy flow analysis and calculation [4], multi-energy system optimization scheduling [2,3], and multi-energy system planning and multi-market games [5,6]

Objectives

Results

Discussion

Conclusion