Techno-Economic Reactive Power Compensation of MV/LV Distribution Transformers

The paper presents the method of reactive power compensation of MV/LV distribution transformers. Given the small participation of reactive load in the total peak power and energy losses in transformers, it is necessary to analyse the financial profitability of each investment in compensation in detail. This work precisely follows this idea. A developed mathematical model in this work allows the determination of optimal power of shunt capacitor and years of investment profitability, taking in consideration annual maintenance costs. For the valuation of revenue due to power loss reduction, investment and maintenance costs in the battery lifetime period, the actualization (net present value) method is used. Two discount rates are imposed in the model in order to illustrate their influence on the optimal power shunt capacitor choice and the investment payback period. The analysis is performed for transformers that are embedded in air and free-standing cement substations of city type. The paper also proposes an optimal shunt capacitor’s power and typical power of MV/LV transformers, where the basic compensation is economically profitable.