ABSTRACT:
In
this paper, transient response of the microgrid caused due to unintended
switching events and faults have been investigated in distributed generation
(DG) system. The proposed technique is based on two new criteria; i) transient
index value (TIV) and ii) positive sequence superimposed current angle at PCC.
The proposed method utilizes three phase voltage signals at DG end to compute
the TIV. The performance of the proposed integrated approach has been evaluated
on a sample test system and a practical distribution network consisting of
combined heat and power plant, wind turbine generators, and photovoltaic
system. The simulation results demonstrate that the proposed technique exhibits
high reliability and leads to faster detection of islanding condition as
compared to the existing passive islanding detection methods not only for zero
active and reactive power mismatch conditions, but also for transient events
caused due to nonlinear loads.
1. Distributed generation
2. Islanding condition
3. Least square approach
4. Power mismatch
5. Voltage signal
CONCLUSION:
In
this paper, two criterion-based approach using TIV derived from three phase
voltages and sign of PSSC angle was proposed for islanding detection. For the
detection of islanding event in microgrid system, the voltage from DG end and
current signal injected to PCC are accessed. The detection methodology has been
tested for different critical conditions such as low active and reactive power
mismatch and results obtained were accurate and reliable. Also, the method is
not prone to false detection even during severe non-islanding conditions such
as capacitor switching, fault conditions, switching of large block of load and
opening of DG end breakers. The presence of nonlinear load has no effect on the
detection using proposed algorithm. With the proposed approach, the
non-detection zone had reduced and hence the reliability of the operation was
assured. Because of faster detection capacity (less than one cycle) and simple
computational procedure, more reliable and secured way to detect islanding
phenomenon is possible in the digital platform using the proposed integrated
technique.
REFERENCES:
[1] IEEE Standard 929-2000: ‘IEEE standard for Interconnecting Distributed Resources with Electric Power Systems’, 2003.
[2] M. A. Redfern, O. Usta, and G. Fielding, “Protection against loss of utility grid supply for a dispersed storage and generation unit”, IEEE Trans Power Del., vol. 8, no. 3, pp. 948-954, Jul. 1993.
[3] W. Wang, J. Kliber, G. Zhang, W. Xu, B. Howell, and T. Palladino, “A power line signaling based scheme for anti-islanding protection of distributed generators-part II: field test results”, IEEE Trans. Power Del. ,vol. 22, no. 3, pp. 1767-1772, Jul. 2007.
[4] W. Xu, G. Zhang, C. Li, W. Wang, G. Wang, and J. Kliber, “A power line signaling based technique for anti-islanding protection of distributed generators-part 1: scheme and analysis,” IEEE Trans. Power Del., vol. 22, no. 3, pp. 1758-1766, Jul. 2007.
[5] P. Gupta, R. S. Bhatia, and D. K. Jain, “Active ROCOF relay for islanding detection,” IEEE Trans. Power Del., vol. 32, no. 1, pp. 420-429, Feb.2017.
