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PMU Holdover Performance Enhancement Using Double-Oven Controlled Oscillator

Phasor measurement units (PMUs) rely on high-precision timing signals obtained from global positioning system (GPS) to guarantee the accuracy of measurements. Unfortunately, GPS receivers inside the PMUs cannot lock to satellite signals frequently, leaving PMUs operating under a holdover condition with degraded accuracy. In this letter, a double-oven controlled oscillator (DOCO) is proposed to be utilized as a solution for PMU holdover reliability enhancement. It can generate timing signal within 1 μs drift to maintain measurement accuracy level for more than 1.5 h in holdover state. Experimental tests are conducted to verify the effectiveness of the DOCO as a reliable alternative time source for PMUs.