Anti-islanding protection in distributed generation with synchronous generators

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CIRED 2019 - 1730.pdf (1.05 MB)
Paper number
1730
Working Group Number
Conference name
CIRED 2019
Conference date
3-6 June 2019
Conference location
Madrid, Spain
Peer-reviewed
Yes
Short title
Convener
Authors
Kulis, Ivan Goran, Koncar-KET, Croatia
Boras, Miljenko, Koncar-KET, Croatia
Abstract
Anti-islanding protection methods are not always reliable due to the existence of non-detection zones (NDZ) in which active and reactive power production and consumption in the rest of the network (island) are close to or are in balance. This problem is especially noticeable when it comes to DG with synchronous generators (for e.g. small Hydro Power Plant (HPP) or Thermal Power Plant (TPP) with cogeneration).Usage of the rate of change of frequency (ROCOF, 81R) has been proven as the most reliable method for undesired island operation detection. But the ROCOF also has its sensitivity limits especially when it comes to synchronous generators which tend to keep their stability on the network. The problem is further enhanced in a week networks (networks with small SC power) where ROCOF can’t be set very sensitive because there are frequency changes even in parallel operation caused by disturbances during bad weather conditions or by load switching.In the article are shown different ROCOF methods and settings with their field test and operational results on small HPP and cogeneration TPP. The method which includes machine automatic voltage regulation (AVR) influence is also described. The intention is to reactive power set point should be periodically changed (≈200-400 ms) in small amount (few (tenths) kVAR). When PP operates in parallel with the network small changes in reactive power have a small (almost negligible) influence on voltage and current but upon islanding this influence rising and consequently cause bigger change of active power and frequency.
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Keywords
Publisher
AIM
Date
2019-06-03
Published in
CIRED 2019 Conference
Permanent link to this record
https://cired-repository.org/handle/20.500.12455/541
http://dx.doi.org/10.34890/768
ISSN
2032-9644
ISBN
978-2-9602415-0-1