Distributed electrical current sensing for DC power networks

"The use of High-Voltage Direct Current (HVDC) power transmission has grown over recent decades as power electronics have enabled DC power to be converted easily to AC, which is a more usable form of electricity. Over the coming decade, demand for HVDC based power systems is expected to rise substantially due to growth in adoption of offshore power generation and an increasing desire to minimise transmission losses. Given this growth in the HVDC transmission market (primarily interconnectors and export cables for offshore generation), it is desirable to develop systems to improve the reliability of DC power transmission platforms.

Synaptec's instrumentation technology integrates optical fibre and piezoelectric technologies to facilitate novel distributed measurements of voltage and current along transmission lines using the pre-installed optical fibres. This offers unprecedented power system visibility for a low cost, enabling new control and protection functions to be implemented on complex circuits. However, present techniques that are successfully employed to measure AC current will not work for measurement of DC current, and new approaches and innovations are required to extend this platform to DC circuits.

In this project, NPL will conduct a literature review of DC current measurement techniques that may be appropriate to be used as part of Synaptec's wide area distributed sensor platform. The merits and drawbacks of potential methods will be compared and the results of this analysis will be used to establish if a suitable method can be realised. Selected methods will be reduced to practice in collaboration with Synaptec. The aim of the work will be to provide Synaptec with a potential solution that can be further developed into a prototype product.

Accessing the DC power transmission market would have significant impact on Synaptec's growth, and the success of this project will benefit the UK economy through development of new IP with the potential to improve the reliability and efficiency of clean power generation and transmission over long distances."