Stochastic Real-time Power Dispatch with Large-scale Wind Power Integration and its Analytical solution

Abstract

Real-time power dispatch (RTD) can coordinate wind farms, automatic generation control (AGC) units and non AGC units. In RTD, the probable wind power forecast errors (WPFE) should be appropriately formulated to ensure system security with high probability and minimize operational cost. Previous studies and our onsite tests show that Cauchy distribution (CD) effectively fits the leptokurtic feature of small timescale WPFE distributions. In this paper, we propose a chance-constrained real time dispatch (CCRTD) model with the WPFE represented by CD. Since the CD is stable and has promising mathematical characteristics, the proposed CCRTD model can be analytically transformed to a convex optimization problem considering the dependence among wind farms outputs. Moreover, the proposed model incorporates an affine control strategy compatible with AGC systems. This strategy makes the CCRTD adaptively take into account both the additional power ramping requirement and power variation on transmission lines caused by WPFE in RTD stage. Numerical test results show that the proposed method is reliable and effective. Meanwhile it is very efficient and suitable for real-time application.