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Precision timing for digital substations in power grid


l'Observatoire de Paris

Customers: Fingrid (Finland), Statnett (Norway) and Paris Oservatory (France)


The power transmission system is increasingly dependent on accurate timing for reliable operation and control. In particular, real-time streaming of data from networked Phasor Measurement Units (PMUs) for wide-area monitoring and automated control implies increasing reliance on accurate, available, and reliable microsecond-level timing. While it is true that GPS based clocks have sufficient accuracy to meet this requirement, they are vulnerable to accidental interference or intentional jamming or spoofing with false GPS signals.


VTT MIKES Metrology, together with Justervesenet (Norway) and Paris Obervatory (France) developed practical methods for using optical fibers to deliver precise time to substations, to be used in parallel with GPS timing. Statnett is currently implementing this dual solution on the Norwegian transmission system.


Using two independent timing sources increases the reliability of the control and measurement systems on substations, and of the power transmission system.