the following are a few DACS messages (already posted about this and other stuff related to this in a seperate topic on the engineering board) regarding a power system upgrade at the NPR NOC in Washington, DC
On Friday evening, 7/20/07, the primary UPS system at NPR is slated to be
replaced. This work, scheduled to start at 2215 ET, is necessary to replace an
aging 125 kVA unit that is nearing the end of its useful life. This
mission-critical unit feeds the AC circuits used in the NOC and in NPR Master
Control, among other places.
The plan is to shunt the power that is normally routed through the primary unit
through a backup UPS while the old primary unit is removed and the new primary
unit is placed into service. Because the current primary unit lacks an external
bypass switch, this power transfer must occur hot, which means that there is
the potential for an electrical short to occur, which would cut power to the
circuits fed by the primary UPS. This would cause ALL satellite transmissions
from the NOC to go down: the legacy channels, the ContentDepot streams, and
the ContentDepot satellite-delivered file transfer service. The ContentDepot
Portal would NOT be affected, as it is on a separate UPS system. This means
that files could still be uploaded to the Portal and downloaded via the http
option. The messaging system and WebDACS will also be unaffected by this work.
Special contractors have been hired to perform this work, contractors who have
done hot changeovers like this before. In addition, we have made arrangements
to utilize the backup legacy uplink in case of an outage to quickly restore
service on 4 channels: NPR Newscasts, the BBC World Service, Classical 24, and
the Beethoven Satellite Network.
There are two hours during this maintenance that are critical: between 2215 and
2315 ET on Friday night, 7/20, and between 0600 and 0700 on Saturday morning,
with the Friday evening hour being the most critical, in terms of the
probability of error. We have met with the contractors and the contract
engineers involved in the work, and they assure us that all precautions are
being taken to protect the health and safety of their workers, and, by
extension, the continuity of service.
Nonetheless, stations may wish to consider using programming from sources other
than the live satellite feeds during the two critical hours. For example, the
Beethoven Satellite Network has posted a one-hour evergreen episode that could
be downloaded and used instead of the live satellite feed. Likewise, there are
a number of file-based programs that will be transmitted over the legacy system
during the hours of this maintenance that could be downloaded from the
ContentDepot for local transmission instead of using the legacy feed.
Again, we expect this work to occur without any interruption in service. When
the work is completed and we have switched back to the new primary UPS, we will
send a notification to the system.
The electricians working on the upgrade to the UPS system at NPR Headquarters
have completed the first phase of the work, which was to re-route power around
the main UPS system to another, temporary UPS System. This was the most
dangerous part of the work as it had to be done while the circuits were still
"hot"; meaning that any mis-step could have affected the operation of the
Washington uplink.
The electricians' next step is to install the replacement main UPS into the
power system. This work is due to be completed before 0700 ET, when the new UPS
will be switched back into the circuit. This next step is much less dangerous
and is less likely to cause any downtime to the satellite transmission system.
We will send another note once the second phase has been completed and
operations are back to normal.
The electricians have completed their work and the new UPS has been switched
into the AC power feed to the NOC. There were no ill effects to any of the
Washington uplink systems, and all operations are back to normal.
The completion of this work means that the operation of the Washington uplink
(and, by extension, the ContentDepot streams and file delivery system) is now
further "hardened" as we have now replaced the aged UPS equipment which was
more prone to failure.
On Friday evening, 7/20/07, the primary UPS system at NPR is slated to be
replaced. This work, scheduled to start at 2215 ET, is necessary to replace an
aging 125 kVA unit that is nearing the end of its useful life. This
mission-critical unit feeds the AC circuits used in the NOC and in NPR Master
Control, among other places.
The plan is to shunt the power that is normally routed through the primary unit
through a backup UPS while the old primary unit is removed and the new primary
unit is placed into service. Because the current primary unit lacks an external
bypass switch, this power transfer must occur hot, which means that there is
the potential for an electrical short to occur, which would cut power to the
circuits fed by the primary UPS. This would cause ALL satellite transmissions
from the NOC to go down: the legacy channels, the ContentDepot streams, and
the ContentDepot satellite-delivered file transfer service. The ContentDepot
Portal would NOT be affected, as it is on a separate UPS system. This means
that files could still be uploaded to the Portal and downloaded via the http
option. The messaging system and WebDACS will also be unaffected by this work.
Special contractors have been hired to perform this work, contractors who have
done hot changeovers like this before. In addition, we have made arrangements
to utilize the backup legacy uplink in case of an outage to quickly restore
service on 4 channels: NPR Newscasts, the BBC World Service, Classical 24, and
the Beethoven Satellite Network.
There are two hours during this maintenance that are critical: between 2215 and
2315 ET on Friday night, 7/20, and between 0600 and 0700 on Saturday morning,
with the Friday evening hour being the most critical, in terms of the
probability of error. We have met with the contractors and the contract
engineers involved in the work, and they assure us that all precautions are
being taken to protect the health and safety of their workers, and, by
extension, the continuity of service.
Nonetheless, stations may wish to consider using programming from sources other
than the live satellite feeds during the two critical hours. For example, the
Beethoven Satellite Network has posted a one-hour evergreen episode that could
be downloaded and used instead of the live satellite feed. Likewise, there are
a number of file-based programs that will be transmitted over the legacy system
during the hours of this maintenance that could be downloaded from the
ContentDepot for local transmission instead of using the legacy feed.
Again, we expect this work to occur without any interruption in service. When
the work is completed and we have switched back to the new primary UPS, we will
send a notification to the system.
The electricians working on the upgrade to the UPS system at NPR Headquarters
have completed the first phase of the work, which was to re-route power around
the main UPS system to another, temporary UPS System. This was the most
dangerous part of the work as it had to be done while the circuits were still
"hot"; meaning that any mis-step could have affected the operation of the
Washington uplink.
The electricians' next step is to install the replacement main UPS into the
power system. This work is due to be completed before 0700 ET, when the new UPS
will be switched back into the circuit. This next step is much less dangerous
and is less likely to cause any downtime to the satellite transmission system.
We will send another note once the second phase has been completed and
operations are back to normal.
The electricians have completed their work and the new UPS has been switched
into the AC power feed to the NOC. There were no ill effects to any of the
Washington uplink systems, and all operations are back to normal.
The completion of this work means that the operation of the Washington uplink
(and, by extension, the ContentDepot streams and file delivery system) is now
further "hardened" as we have now replaced the aged UPS equipment which was
more prone to failure.