ABB RELION 670 SERIES Manual page 111

1MRK 511 399-UEN B
670 series 2.2 IEC
Cyber security deployment guideline
UTC Coordinated Universal Time. A coordinated time scale,
maintained by the Bureau International des Poids et Mesures
(BIPM), which forms the basis of a coordinated dissemination
of standard frequencies and time signals. UTC is derived from
International Atomic Time (TAI) by the addition of a whole
number of "leap seconds" to synchronize it with Universal
Time 1 (UT1), thus allowing for the eccentricity of the Earth's
orbit, the rotational axis tilt (23.5 degrees), but still showing
the Earth's irregular rotation, on which UT1 is based. The
Coordinated Universal Time is expressed using a 24-hour
clock, and uses the Gregorian calendar. It is used for
aeroplane and ship navigation, where it is also sometimes
known by the military name, "Zulu time." "Zulu" in the
phonetic alphabet stands for "Z", which stands for longitude
zero.
VPN A Virtual Private Network (VPN) extends a private network
across public networks like the Internet. It enables a host
computer to send and receive data across shared or public
networks as if it were a private network with all the
functionality, security and management policies of the private
network.
Section 9
Glossary
105