Scheduled Perturbation To Reduce Nondetection Zone For Low Gain Sandia Frequency Shift Method

Keywords

Distributed generation (DG); islanding detection; nondetection zone (NDZ); Sandia frequency shift (SFS)

Abstract

It is known that the choice of gain (K) in the Sandia frequency shift (SFS) scheme has direct impacts on the stability of a system with grid-connected distributed generations (DGs). In this paper, a scheduled perturbation technique is proposed to reduce the stability impact of K. In the proposed technique, chopping fraction (cf) is used to compensate for reduction in the value of K, where higher cf values are used to achieve zero nondetection zone (NDZ) under low gain SFS. It is shown by analysis that theoretical reduction of NDZ can be always achieved for a nonzero value of cf. Simulations for single- and multi-DGs systems are performed to verify the analytical analysis. It is shown that an appropriate design of scheduled signal duty cycle (d) is of critical importance to realize the proposed reduction in NDZ. While close synchronization of perturbation signals for multi-DG system is required, a delay of 0.33 s is shown to be tolerated for a two-DG system. Synchronization can be achieved either through locally synchronized timers or by limited communication among DGs. The proposed technique provides an attractive option for systems with high DG penetration by reducing the negative impact of K on stability.

Publication Date

11-1-2015

Publication Title

IEEE Transactions on Smart Grid

Volume

6

Issue

6

Number of Pages

3095-3103

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1109/TSG.2015.2423554

Socpus ID

84960336645 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84960336645

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