Authors: Tahmina Hoque, Doug Arnold Increased use of alternate energy sources with intermittent production, makes balancing energy flows in power grids more complex.  This has led to an increased dependency on synchrophasor measurements of current and voltage throughout the network to detect energy flow instabilities before they lead to a cascade blackout.  Grid operators need to compare the measurements throughout the grid on the same timescale, The IEEE Standard for Synchrophasor Measurements for Power Systems (IEEE C37.118) establishes a time synchronization requirement of 1us to UTC for all phase measurement units.  This specification ensures that the contribution to measurement error remains significantly below 1% of the total vector error.  Typically, in substations UTC is derived from a GNSS receiver (or two) and distributed using PTP and IRIG-B. For resilience against GNSS failures, including those caused by jamming and detected spoofing attempts, holdover oscillators and alternative sources of time are desired.  One such source can be PTP from a nearby substation, which is unaffected by the GNSS disturbance due to distance.  Also, since power grid substations are typically connected to a telecom-like network, the use of a telecom profile for this purpose is an attractive option.  Time received in this fashion can be converted to power profile PTP using an inter-working function (IWF), as defined in ITU-T G.8275.    The IWF was created by the ITU for translating between different telecom PTP profiles, but the concept is adaptable to translating from the G.8275.2 telecom profile to the IEC 61850-9-3 power utility profile, for example.  Using the IWF approach the two profiles operate in different PTP domains, so the Grandmaster (GM) of the substation domain is combined with a timeReceiver in the telecom domain.  In this presentation, we will propose guidelines for proper PTP protocol translation, including how the power profile Grandmaster (GM) clock quality attributes are determined.