A commercial/industrial photovoltaic system is usually mounted either on the rooftop of a building or on the ground and typically features a capacity between 20 to 1000 kW. Nowadays, following the decreasing investment cost to set up a photovoltaic system and environmental concerns, the market of Building-Integrated Photovoltaics using solar panels as outer layer to generate electricity, is growing steadily. Main issues in commercial/industrial applications are the following:
- Reverse Power Flow
Usually an electric power grid is not designed to manage two way power flows at the distribution level. They are designed as a radial system with the energy flowing one way and over long distances, from a large centralized generator down to many customer loads at the end of the distribution network. Recently, as distributed solar photovoltaic generation on rooftops is more and more widespread, reverse power flows could go back up to substations and transformers, causing significant challenges to the grid. This has effects on protection coordination and voltage regulators
- Ramp rates
As power generation in photovoltaic system rely on sun exposure, rapid fluctuations of the power coming from the photovoltaic system could cause undesirable levels of voltage variability in the distribution feeder. This voltage variability reduces the stability of the grid due to transient imbalance between load and generation. The consequence is that voltage and frequency could exceed set limits because the centralized generators cannot ramp fast enough to match the variability of the photovoltaic systems, causing frequency mismatch overall the grid and leading sometime to blackouts.
The ABB product range includes circuit breakers, switch disconnectors, fuse disconnectors, residual current-operated circuit-breakers, grid connection relays, surge arresters, voltage & current sensors and remote switching contactors all specially designed to prevent and manage this kind of problems.