Load shedding (LS) is the last firewall and the most expensive control action against power system blackout. Conventional under frequency LS (UFLS) schemes determine the load drop locations independently of the event magnitude, being the location, frequency thresholds and stage time delays of LS relays pre-specified and constant values.

In the decentralised method proposed in this project the aforementioned settings are determined online based on voltage deviation from pre-disturbance value. It means that higher frequency thresholds are assigned to the loads that experience more voltage decay, which are typically located in the vicinity of disturbance location, leading to the need of curtailing less power and thus, to disconnect fewer users during the emergency shutdown. At the same time the proposed method is able to bring the voltage and frequency to the desired interval faster than the UFLS.

The proposed method simultaneously benefits from individual UFLS and under voltage LS (UVLS) features which operate in the power system without coordination.

The Market

The project is a mix of research/development and thus, the market analysis below is limited. Possible future commercialisation of the technology will be made exclusively by InoPower with a distribution of royalties between partners to be decided after the funding approval.

Target group and added value for consumers

The market for protective relays can be segmented into two basic categories on the basis of type and product. On the basis of type, the market can be divided in low, medium and high voltage devices. The medium and high voltage segments are usually preferred by utility and large industrial consumers. The market can also be segmented on the basis of product cate-gory as feeder, motor, transmission line and transformer protection systems. The market is often segmented on the basis of the product categories, in which the feeder protection sys-tem is estimated to dominate the market.

The current global protective relay market is expected to double by 2020. The most promi-nent reasons for this growth in the market are increasing investments in infrastructure, as well as in the number of retrofit projects.

The market revenues for protective relays are growing at a steady rate, where the power generation, transmission and distribution sectors accounts for the largest share of market revenues, followed by the industrial sector. Protection relays are typically not bought by resi-dential customers and this segment does not account for a significant share of the protective relay market. Load shedding accounts for large industrial financial losses, besides disruption in day life, leading in some cases to an increase in accidents and crime. The technology de-veloped in this project will reduce the amount of load shedding during emergency situations and minimize the costs associated with it. No economic evaluations have yet been made, but some of simulated cases in benchmark models show a reduction in the amount of load shed-ding around 30% when compared with traditional approaches.

This will be achieved at minimum cost, as the existing technology already has the required hardware and input signals, being only necessary to design and test the new algorithms. Moreover, some of the existing costs may even be reduced, as the proposed method has no communication requirements between different points.