The electricity network in the South East of England has become more challenging to manage both for the transmission and distribution network operators due to increased distributed generation connection and increased power flows on transmission interconnectors to and from continental Europe. UK Power Networks (UKPN), the distribution network operator (DNO), has trialled for the first time online contingency analysis on a distribution network in Great Britain. The Kent Active System Management project aims to demonstrate the benefits of using a contingency analysis system for both operational and planning time frames. This study describes challenges and the recommended approach to overcome data exchange and data-quality challenges when developing a real-time power flow model from existing datasets. It provides a real-world example of dealing with data exchange and also highlights the need for transmission system operator/DNO coordination.