Risk Assessment for 11kV Unsecured Rings in Distribution Utilities in UAE Based on Probabilistic Approach

AlAhmad, Omar; Abdel-Galil, T.K.

doi:10.1109/icrega50506.2021.9388299

Cited by 3 publications

(2 citation statements)

References 8 publications

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“…The chart in Fig. 3 represents the loading percentages of the rings based on the N-1 firm capacity to comply with DoE regulations [5]. In general, the selected rings have different loadings (lightly to fully) loaded for each ring type.…”

Section: Selected Ringsmentioning

confidence: 99%

“…Furthermore, any fault that occurs at any 11 kV cable will be detected by a DC powered numerical overcurrent and earth fault protection device, which sends signal to the respective CB at the feeder heads X or Y based on the feeding source for the fault isolation. However, it's well known that the failure rate of the cables is much higher where the average failure cable rate in the region during last 5-years is 1.62 failure/100 km/year [5]. So, it's more likely to have frequent load disturbance from one side of the ring up to the NOP at any 11 kV fault.…”

Section: Introductionmentioning

confidence: 99%

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Parallel Operation for 11 kV Ring System with Normally Open Point at Distribution Networks in AADC

AlAhmad,

AlDahmi,

Rayees

2024

J. Phys.: Conf. Ser.

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Currently, Al Ain Distribution Company (AADC) 11 kV distribution circuits are electrically split by Normal Open Points (NOP)s. NOPs can be closed for load restoration in case of planned or unplanned outages. Also, changing the NOP locations helps in load shifting to achieve network optimization between adjacently located 33/11 kV primary substations. This paper discusses a new operation mode in medium voltage distribution power network of AADC at Al Ain area in the United Arab Emirates by introducing closed loops of parallel 11 kV feeders from different busbars or substations. This operation mode is intended to end the continuous debate of optimal NOP locations in addition to expected reduction in the required time for load restoration in case of failures at distribution (11/0.4 kV) substations. A detailed case study is performed to explore the achieved benefits and enhancements on load balancing, voltage profile, and power factor in medium voltage networks. On the other hand, the impact on load flow, protection scheme, and loading violation are evaluated. Furthermore, the proposed model is in line with the regulations of the Department of Energy (DoE), regulatory body in Abu Dhabi Emirate, and should fully comply with Electricity Distribution Code (EDC) of Security of Supply Standards. Accordingly, while the current used operation mode is still valid, it is found that closed loops arrangement can be only allowed for rings from same 33/11 kV substations feeding from same source with considerable protection limitations. Moreover, it was concluded that closed loops from different 33/11 kV Substations will result in load flow problems.

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Section: Selected Ringsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%