Unbalanced three-phase continuation power flow for distribution networks with distributed generation

Abstract

Continuation power flow is an important tool for assessing power system voltage stability. A continuation power flow method for distribution networks is proposed in view of unbalanced three-phase lines and loads in distribution networks with distributed generations (DG). The proposed method consists of tangent predictor and Newton corrector. A local geometric parameterization technique is utilized for the characteristics of the P-V curves of unbalanced three-phase systems. A doubleswitching logic is proposed for handling the capability constraints of DGs which modeled as PV and PQ buses. A scheme for identifying the type of bifurcation is also given. Simulation results on IEEE 33-bus distribution system show that the proposed method is effective in tracing the P-V curves of threephase distribution systems and computing the voltage stability critical point as well as identifying the type of bifurcation.

Distributed continuation power flow method for integrated transmission and active distribution network

“…The distribution grid carries out CPF computation by employing the local geometric parameterization to handle the special properties of three-phase P-V curves [17]. The extended power flow equations are formulated as…”

“…This is because the essential reason leads to the voltage collapse of an integrated power system is the load increase of the distribution grid and the Jacobin matrix of integrated system becomes singular due to the singularity of the submatrix of the distribution grid, which cannot be reflected in the traditional independent transmission CPF. Since the three phases of distribution system are unbalanced, the weakest phase is the main reason for the voltage collapse in unbalanced DNs and has an impact on the voltage stability of the integrated system [17]. Thus the traditional independent transmission CPF may bring inaccurate computational results.…”

“…The CPF method has been validated to be a good method to compute the load margins of both TPSs and DNs and it could consider the inequality constraints which describe the nonlinear characteristics of electrical components [10][11][12][13][14][15][16][17]. In [18] a distributed CPF method was presented to compute the available transfer capability (ATC) of interconnected power grid which is composed of many transmission sub-grids.…”

Fast Calculation Method for Continuous Power Flow of Microgrid Based on Levenberg-Marquardt Algorithm

“…The existing innovations in power flow calculation algorithms mainly rely on the continuous power flow calculation method [2], [3], [4], [5], [6], the trust-region method [7], [8] and the Levenberg-Marquardt (L-M) algorithm [9], [10].…”

Research of active load regulation method for distribution network considering distributed photovoltaic and electric vehicles

“…As an important component of smart grid, one of the goals of smart distribution network is to solve the operation problem of a large number of distributed generations (DGs) [1]. At present, with the development of renewable energy sources, distributed photovoltaic (PV) and electric vehicles (EVs) have been put into large‐scale application [2].…”