PAPER ON FEEDER RECONFIGURATION FOR LOSS REDUCTION IN THREE PHASE DISTRIBUTION SYSTEM UNDER UNBALANCED LOADING CONDITION

Authored by: N. Rugthaicharoencheep and S. Sirisumrannukul

Unbalanced loading in electrical networks creates higher losses compared to balanced lines having the same loads. Reconfiguring the set up of the loads reduces the line losses not only to its phase conductors but also to the neutral wire for four-wire system.

ABSTRACT - This paper presents a method to find the optimal implementation of feeder reconfiguration in unbalanced loading of distribution systems with the objective of power loss reduction. The optimization problem is subjected to system constraints consisting of load-point voltage limits, radial configuration format, no load-point interruption and feeder capability limits.

The system power losses and bus voltages are solved by a three-phase power flow algorithm. The solution technique developed based on Tabu search is employed to search switch statuses for feeder reconfiguration under different unbalanced loading conditions.

The performance of the developed methodology is demonstrated by a radial distribution system with 69 buses, 7 laterals and 5 tie-lines (looping branches). The study results how that the optimal on/off patterns of the switches can be identified which give the minimum power loss while satisfying all the constraints.

CONCLUSION-A Tabu search-based optimization technique has presented in this paper to find the most appropriate topology of the distribution system under unbalanced loading conditions. With the presence of unbalanced distribution systems, three phase power flow analysis is required. The objective function of feeder reconfiguration is to minimize the total system active power loss.

The objective function is subjected to the threephase power flow equations, bus voltage limits, current transfer capability of feeders, radial configuration format, and no loadpoint interruption. A 69-bus distribution system is used to demonstrate the effectiveness of the proposed technique.

The study results with different unbalanced loading conditions show that the optimal on/off patterns of sectionalzing switches and tie switches can be identified to give the minimum power loss, introducing significant savings on the annual cost of energy loss in the system.

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