Analysis of Current Limiting Algorithm with Anti-Windup Control for Transient Stability of Grid-Forming Converters

Year 2023, Volume: 38 Issue: 3, 671 - 681, 18.10.2023

Özgür Çelik

https://doi.org/10.21605/cukurovaumfd.1377721

Abstract

In modern power grids, renewable energy sources (RESs) are integrated to the grid through voltage source converters (VSCs) with grid-forming capabilities. Grid forming VSCs’ weak overcurrent capability revealed the need for current limiting techniques under large disturbances like short-circuit faults. However, current saturation algorithms induce transient instabilities due to the AC voltage controller windup issue when the current is saturated. Therefore, analyzing the transient stability of the grid-forming units in case of fault conditions is crucial for ensuring the reliable and secure operation of the grid. This paper investigates the effects of the current limiting algorithm with anti-windup control to handle transient instabilities during fault conditions. An elaborated theoretical analysis of the presented system is performed by considering different case studies. The simulations are conducted by using Matlab/Simulink software to test the validity of the presented system. The obtained results highlight the advantages of an anti-windup controller during current saturation mode.

Keywords

VSCs, Grid-forming, Current saturation, Anti-windup, Power flow control

Şebeke-Şekillendirici Dönüştürücülerin Geçici Durum Kararlılığı için Anti-Windup Kontrollü Akım Sınırlama Algoritmasının Analizi

Abstract

Modern güç şebekelerinde, yenilenebilir enerji kaynakları (YEK'ler) şebeke oluşturma kabiliyetine sahip gerilim kaynağı dönüştürücüleri (VSC'ler) aracılığıyla şebekeye entegre edilmektedir. Şebeke oluşturan VSC'lerin düşük aşırı akım kapasitesi, kısa devre arızaları gibi büyük bozulmalar altında akım sınırlama tekniklerine olan ihtiyacı ortaya çıkarmıştır. Ancak, akım doyum algoritmaları, akım doyuma ulaştığında AC gerilim kontrolörünün windup sorunu nedeniyle geçici kararsızlıklara neden olur. Bu nedenle, arıza durumlarında şebeke oluşturan birimlerin geçici kararlılığının analiz edilmesi, şebekenin güvenilir ve emniyetli çalışmasını sağlamak için çok önemlidir. Bu makale, arıza koşulları sırasında geçici kararsızlıkların üstesinden gelmek için windup önleyici kontrollü akım sınırlama algoritmasının etkilerini araştırmaktadır. Sunulan sistemin ayrıntılı bir teorik analizi, farklı vaka çalışmaları dikkate alınarak gerçekleştirilmiştir. Simülasyonlar, sunulan sistemin geçerliliğini doğrulamak için Matlab/Simulink yazılımı kullanılarak gerçekleştirilmiştir. Elde edilen sonuçlar, akım doygunluk modu sırasında bir windup önleyici kontrolörün avantajlarını vurgulamaktadır.

Keywords

VSCs, Şebeke-şekillendirici, Akım doyum, Anti-windup, Güç akışı kontrolü

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