Load-shedding strategy using a zero-sequence power supply scheme for distribution networks in a modern home or building

Abstract

In this paper, a novel load-shedding technology based on the zero-sequence power supply (ZPS) principle is proposed. The principle is simple to understand, and is based on the symmetric composition method. This technology can rapidly shed loads (three-phase loads and some single-phase loads), which helps in reducing economic losses and equipment costs in the event of a shortage of electricity. The ZPS scheme is based on the selection of one of the three source lines (A-, B-, or C-phase), and then the power is fed to single-phase loads connected between any phases-to-neutral lines. In other words, three-phase and single-phase loads connected between any two-phase lines on the demand side will automatically be shed. In addition, this paper proposes a three-phase distribution transformer with a delta-connected neutral-grounded structure (DNGS). The distribution transformer with a DNGS can provide multi-voltage solutions to supply and meet a variety of loads during the normal power supply (NPS), in order to reduce the additional investment, as well as to simplify design and planning for the distribution networks of a home or building. It can also continuously supply electricity for single-phase loads between phase-to-neutral lines during the ZPS. The proposed method and obtained results are of value to system managers, engineers, and operators, especially the load shedding during power shortages in the distribution networks of a modern home or building.