Rolls-royce Corporation

Alstom Technology Limited

Schneider Electric Energy UK Ltd.

Graeme Burt

Stuart J Galloway

Patrick Norman

Adam Dysko

Ryan M Tumilty

A phase angle drift method for loss of mains/grid protection is disclosed. According to one aspect, an accumulated electrical phase angle drift derived from the difference between the current measured local frequency and the estimated frequency using historical data is compared to an angle threshold. An estimated grid frequency may be calculated based on the historical delay, and the window, over which the estimated frequency is calculated. An addition/subtraction of a phase angle offset value is calculated for a half cycle is performed when the frequency difference between the estimated frequency fand the measured frequency fis greater or equal to a first determined value.

Phase angle drift method for loss of mains/grid protection

A DC electrical power system has a power generator converter system, a positive supply rail extending from the converter system, a negative supply rail extending from the converter system, and a midpoint earthing arrangement operatively connecting to the supply rails. The earthing arrangement is connected to earth by a solid earth connection. The network further has a first protective device on one of the supply rails which in case of a fault is operable to interrupt current flowing on that rail, and a second protective device on the earthing arrangement which in case of a fault is operable to interrupt current flowing to earth through the solid earth connection.

DC electrical power system

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Johnstone, United Kingdom

Graeme Burt